| 1. |
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| 2. |
- Abbasi, Rasha, et al.
(författare)
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IceCube search for neutrinos from GRB 221009A
- 2023
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Ingår i: Proceedings of 38th International Cosmic Ray Conference (ICRC 2023). - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- GRB 221009A is the brightest Gamma Ray Burst (GRB) ever observed. The observed extremelyhigh flux of high and very-high-energy photons provide a unique opportunity to probe the predictedneutrino counterpart to the electromagnetic emission. We have used a variety of methods to searchfor neutrinos in coincidence with the GRB over several time windows during the precursor, promptand afterglow phases of the GRB. MeV scale neutrinos are studied using photo-multiplier ratescalers which are normally used to search for galactic core-collapse supernovae neutrinos. GeVneutrinos are searched starting with DeepCore triggers. These events don’t have directionallocalization, but instead can indicate an excess in the rate of events. 10 GeV - 1 TeV and >TeVneutrinos are searched using traditional neutrino point source methods which take into accountthe direction and time of events with DeepCore and the entire IceCube detector respectively. The>TeV results include both a fast-response analysis conducted by IceCube in real-time with timewindows of T0 − 1 to T0 + 2 hours and T0 ± 1 day around the time of GRB 221009A, as well asan offline analysis with 3 new time windows up to a time window of T0 − 1 to T0 + 14 days, thelongest time period we consider. The combination of observations by IceCube covers 9 ordersof magnitude in neutrino energy, from MeV to PeV, placing upper limits across the range forpredicted neutrino emission.
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| 3. |
- Jansson, Andreas, et al.
(författare)
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Range-based radar model structure selection
- 2021
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Ingår i: 28th European Signal Processing Conference, EUSIPCO 2020 - Proceedings. - 2219-5491. - 9789082797053 ; 2021-January, s. 2269-2273
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Konferensbidrag (refereegranskat)abstract
- In this work, we study under which circumstances it is appropriate to use simplified models for range determination using radar. Typically, pulsed radar systems result in the backscattered, demodulated, and matched signal having a chirp signal structure, with the frequency rate being related to the range to the reflecting target and the relative velocity of the transmitter and reflector. Far from the target, and at low relative velocities, one may achieve preferable location estimates by neglecting the frequency rate, treating the received signal as being purely sinusoidal, whereas at close range, neglecting the frequency rate notably reduces the achievable performance. Using misspecified estimation theory, we derive a lower bound of the achievable performance when neglecting the true signal structure, and show at which ranges one model is preferable to the other. Numerical results from a mm-wave radar system illustrate the results.
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| 4. |
- Jansson, Andreas, et al.
(författare)
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Robust Localization of Close-Range Radar Reflections
- 2023
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Ingår i: Conference Record of the 57th Asilomar Conference on Signals, Systems and Computers, ACSSC 2023. - 9798350325744 ; , s. 549-553
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Konferensbidrag (refereegranskat)abstract
- In order to allow for a computationally efficient estimation of radar reflections, one commonly assumes the reflecting target to be in the far-field of the sensing array, such that the impinging wavefront is modeled as a linear phase-shift along the array. This works well in most radar scenarios, but causes significant performance degradation for close-range radar systems, wherein the curvature of the impinging wavefront may not be neglected. In this work, we examine how the used far-field assumption limits the resulting performance, illustrating how the (misspecified) Cramér-Rao lower bound (CRLB), taking the model mismatch into account, significantly devi-ates from the true CRLB for close-range targets. We further introduce a robust estimator that allows for the waveform cur-vature, showing that this computationally efficient estimator allows for superior performance for close-range reflectors.
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| 5. |
- Kirchhof, Paulus, et al.
(författare)
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Comprehensive risk reduction in patients with atrial fibrillation : emerging diagnostic and therapeutic options - a report from the 3rd Atrial Fibrillation Competence NETwork/European Heart Rhythm Association consensus conference
- 2012
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Ingår i: Europace. - : Oxford University Press (OUP). - 1099-5129 .- 1532-2092. ; 14:1, s. 8-27
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Forskningsöversikt (refereegranskat)abstract
- While management of atrial fibrillation (AF) patients is improved by guideline-conform application of anticoagulant therapy, rate control, rhythm control, and therapy of accompanying heart disease, the morbidity and mortality associated with AF remain unacceptably high. This paper describes the proceedings of the 3rd Atrial Fibrillation NETwork (AFNET)/European Heart Rhythm Association (EHRA) consensus conference that convened over 60 scientists and representatives from industry to jointly discuss emerging therapeutic and diagnostic improvements to achieve better management of AF patients. The paper covers four chapters: (i) risk factors and risk markers for AF; (ii) pathophysiological classification of AF; (iii) relevance of monitored AF duration for AF-related outcomes; and (iv) perspectives and needs for implementing better antithrombotic therapy. Relevant published literature for each section is covered, and suggestions for the improvement of management in each area are put forward. Combined, the propositions formulate a perspective to implement comprehensive management in AF.
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| 8. |
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| 9. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 10. |
- Ahlberg, Patrik, et al.
(författare)
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Defect formation in graphene during low-energy ion bombardment
- 2016
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Ingår i: APL Materials. - : AIP Publishing. - 2166-532X. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar+ ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV's up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Aidemark, Lars-Göran, et al.
(författare)
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The importance of balanced scorecards in hospitals
- 2010
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Ingår i: Performance measurement and management control. - : Emerald Group Publishing Limited. - 9781849507240 ; , s. 363-385
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Al-Adili, Ali, et al.
(författare)
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Analysis of prompt fission neutrons in U-235(nth,f) and fission fragment distributions for the thermal neutron induced fission of U-234
- 2016
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Ingår i: CNR*15 - 5th International Workshop On Compound-Nuclear Reactions And Related Topics. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- This paper presents the ongoing analysis of two fission experiments. Both projects are part of the collaboration between the nuclear reactions group at Uppsala and the JRC-IRMM. The first experiment deals with the prompt fission neutron multiplicity in the thermal neutron induced fission of U-235(n,f). The second, on the fission fragment properties in the thermal fission of U-234(n,f). The prompt fission neutron multiplicity has been measured at the JRC-IRMM using two liquid scintillators in coincidence with an ionization chamber. The first experimental campaign focused on U-235(nth,f) whereas a second experimental campaign is foreseen later for the same reaction at 5.5 MeV. The goal is to investigate how the so-called saw-tooth shape changes as a function of fragment mass and excitation energy. Some harsh experimental conditions were experienced due to the large radiation background. The solution to this will be discussed along with preliminary results. In addition, the analysis of thermal neutron induced fission of U-234(n,f) will be discussed. Currently analysis of data is ongoing, originally taken at the ILL reactor. The experiment is of particular interest since no measurement exist of the mass and energy distributions for this system at thermal energies. One main problem encountered during analysis was the huge background of U-235(nth, f). Despite the negligible isotopic traces in the sample, the cross section difference is enormous. Solution to this parasitic background will be highlighted.
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| 16. |
- Al-Adili, Ali, et al.
(författare)
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Fission Activities of the Nuclear Reactions Group in Uppsala
- 2015
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Ingår i: Scientific Workshop on Nuclear Fission Dynamics and the Emission of Prompt Neutrons and Gamma Rays, THEORY-3. - : Elsevier BV. ; , s. 145-149
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Konferensbidrag (refereegranskat)abstract
- This paper highlights some of the main activities related to fission of the nuclear reactions group at Uppsala University. The group is involved for instance in fission yield experiments at the IGISOL facility, cross-section measurements at the NFS facility, as well as fission dynamics studies at the IRMM JRC-EC. Moreover, work is ongoing on the Total Monte Carlo (TMC) methodology and on including the GEF fission code into the TALYS nuclear reaction code. Selected results from these projects are discussed.
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| 17. |
- Al-Adili, Ali, et al.
(författare)
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Ion counting efficiencies at the IGISOL facility
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.
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| 18. |
- Al-Adili, Ali, et al.
(författare)
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Neutron-multiplicity experiments for enhanced fission modelling
- 2017
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 9782759890200
-
Konferensbidrag (refereegranskat)abstract
- The nuclear de-excitation process of fission fragments (FF) provides fundamental information for the understanding of nuclear fission and nuclear structure in neutron-rich isotopes. The variation of the prompt-neutron multiplicity, ν(A), as a function of the incident neutron energy (En) is one of many open questions. It leads to significantly different treatments in various fission models and implies that experimental data are analyzed based on contradicting assumptions. One critical question is whether the additional excitation energy (Eexc) is manifested through an increase of ν(A) for all fragments or for the heavy ones only. A systematic investigation of ν(A) as a function of En has been initiated. Correlations between prompt-fission neutrons and fission fragments are obtained by using liquid scintillators in conjunction with a Frisch-grid ionization chamber. The proof-of-principle has been achieved on the reaction 235U(nth,f) at the Van De Graff (VdG) accelerator of the JRC-Geel using a fully digital data acquisition system. Neutrons from 252Cf(sf) were measured separately to quantify the neutron-scattering component due to surrounding shielding material and to determine the intrinsic detector efficiency. Prelimenary results on ν(A) and spectrum in correlation with FF properties are presented.
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| 19. |
- Al-Adili, Ali, et al.
(författare)
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Prompt fission neutron yields in thermal fission of U-235 and spontaneous fission of Cf-252
- 2020
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Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 102:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: The sharing of excitation energy between the fission fragments is one of the key issues in studying nuclear fission. One way to address this is by studying prompt-fission neutron multiplicities as a function of other fission observables such as the mass, (nu) over bar (A). These are vital benchmark data for both fission and nuclear deexcitation models, putting constrains on the fragment excitation energy and hence on the competing prompt neutron/gamma-ray emission. Despite numerous detailed studies, recent measurements done at JRC-Geel with the SCINTIA array in the epithermal region show surprisingly strong discrepancies to earlier thermal fission data and the Wahl systematics. Purpose: The purpose was to perform measurements of the prompt-fission neutron multiplicity, as a function of fragment mass and total kinetic energy (TKE), in U-235(n(th), f) and Cf-252(sf), to verify and extend the SCINTIA results. Another goal was to validate the analysis methods, and prepare for planned investigations at excitation energies up to 5.5 MeV. Methods: The experiments were conducted at the former 7 MV Van de Graaff facility in JRC-Geel, using a Twin Frisch-Grid Ionization Chamber and two liquid scintillation detectors. A neutron beam with an average energy of 0.5 MeV was produced via the Li-7(p,n) reaction. The neutrons were thermalized by a 12 cm thick block of paraffin. Digital data acquisition systems were utilized. Comprehensive simulations were performed to verify the methodology and to investigate the role of the mass and energy resolution on measured (nu) over bar (A) and (nu) over bar (TKE) values. The simulation results also revealed that the partial derivative(nu) over bar/partial derivative A and partial derivative(TKE) over bar/partial derivative(nu) over bar are affected by the mass and energy resolution. However, the effect is small for the estimated resolutions of this work. Detailed Fluka simulations were performed to calculate the fraction of thermal neutron-induced fission, which was estimated to be about 98%. Results: The experimental results on (nu) over bar (A) are in good agreement with earlier data for Cf-252(sf). For U-235(n(th), f), the (nu) over bar (A) data is very similar to the data obtained with SCINTIA, and therefore we verify these disclosed discrepancies to earlier thermal data and to the Wahl evaluation. The experimental results on (nu) over bar (TKE) are also in agreement with the data at epithermal energies. For Cf-252(sf) a slope value of partial derivative(TKE) over bar/partial derivative(nu) over bar = (-12.9 f 0.2) MeV/n was obtained. For U-235(n(th), f) the value is (-12.0 +/- 0.1) MeV/n. Finally, the neutron spectrum in the center-of-mass system was derived and plotted as a function of fragment mass. Conclusions: This work clearly proves the lack of accurate correlation between fission fragment and neutron data even in the best-studied reactions. The new results highlight the need of a new evaluation of the prompt-fission multiplicity for U-225(n(th), f).
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| 20. |
- Al-Adili, Ali, et al.
(författare)
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Simulations of the fission-product stopping efficiency in IGISOL
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 51:59, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- At the Jyväskylä Ion Guide Isotope Separator On-Line (IGISOL) facility, independent fission yields are measured employing the Penning-trap technique. Fission products are produced, e.g. by impinging protons on a uranium target, and are stopped in a gas-filled chamber. The products are collected by a flow of He gas and guided through a mass separator to a Penning trap, where their masses are identified. This work investigates how fission-product properties, such as mass and energy, affect the ion stopping efficiency in the gas cell. The study was performed using the Geant4 toolkit and the SRIM code. The main results show a nearly mass-independent ion stopping with regard to the wide spread of ion masses and energies, with a proper choice of uranium target thickness. Although small variations were observed, in the order of 5%, the results are within the systematic uncertainties of the simulations. To optimize the stopping efficiency while reducing the systematic errors, different experimental parameters were varied; for instance material thicknesses and He gas pressure. Different parameters influence the mass dependence and could alter the mass dependencies in the ion stopping efficiency.
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| 21. |
- Al-Adili, Ali, et al.
(författare)
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Studying fission neutrons with 2E-2v and 2E
- 2018
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Ingår i: SCIENTIFIC WORKSHOP ON NUCLEAR FISSION DYNAMICS AND THE EMISSION OF PROMPT NEUTRONS AND GAMMA RAYS (THEORY-4). - : EDP Sciences. - 9782759890316
-
Konferensbidrag (refereegranskat)abstract
- This work aims at measuring prompt-fission neutrons at different excitation energies of the nucleus. Two independent techniques, the 2E-2v and the 2E techniques, are used to map the characteristics of the mass-dependent prompt fission neutron multiplicity, 7(A), when the excitation energy is increased. The VERDI 2E-2v spectrometer is being developed at JRC-GEEL. The Fission Fragment (FF) energies are measured using two arrays of 16 silicon (Si) detectors each. The FFs velocities are obtained by time-of-flight, measured between micro-channel plates (MCP) and Si detectors. With MCPs placed on both sides of the fission source, VERDI allows for independent timing measurements for both fragments. Cf-252(sf) was measured and the present results revealed particular features of the 2E-2v technique. Dedicated simulations were also performed using the GEF code to study important aspects of the 2E-2v technique. Our simulations show that prompt neutron emission has a non-negligible impact on the deduced fragment data and affects also the shape of 17(A). Geometrical constraints lead to a total-kinetic energy-dependent detection efficiency. The 2E technique utilizes an ionization chamber together with two liquid scintillator detectors. Two measurements have been performed, one of Cf-252(sf) and another one of thermal-neutron induced fission in U-235(n,f). Results from Cf-252(sf) are reported here.
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| 22. |
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| 23. |
- Alexandersson, Anna, et al.
(författare)
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Digitalization of bookkeeping in small organization: The case of Sweden
- 2023. - 1
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Ingår i: Handbook in big data analysis in accounting and auditing. - Singapore : Springer Nature Singapore. - 9789811944598 - 9789811944604 ; , s. 133-162
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Bokkapitel (refereegranskat)abstract
- Bookkeeping and accounting is a prevalent feature of small organizations, which has changed face quite substantially with the advent of personal computers and, later, the Internet. The emergence of digitalized accounting procedures has taken place in a nexus of different types of actors (e.g., software developers, accountancy firms and the businesses themselves), regulatory frameworks (e.g., bookkeeping laws and accounting standards) and technical frameworks (e.g., standards for software interactions with banks and tax authorities). Altogether, this has made the paths taken in this process to be largely national. In general, this process of digitalization is largely undocumented and untheorized in research despite its profound impact on practice. Against this backdrop, this chapter has a descriptive and forward-looking approach, documenting the case of how Swedish bookkeeping practices of small organizations became digitalized, which can work as a reference case for comparisons with other national contexts.
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| 24. |
- Alexandersson, Anna, et al.
(författare)
-
Digitalization of Bookkeeping in Small Organizations : The Case of Sweden
- 2023
-
Ingår i: Handbook of Big Data and Analytics in Accounting and Auditing. - Singapore : Springer. - 9789811944604 - 9789811944598 - 9789811944628 ; , s. 133-162
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Bookkeeping and accounting is a prevalent feature of small organizations, which has changed face quite substantially with the advent of personal computers and, later, the Internet. The emergence of digitalized accounting procedures has taken place in a nexus of different types of actors (e.g., software developers, accountancy firms and the businesses themselves), regulatory frameworks (e.g., bookkeeping laws and accounting standards) and technical frameworks (e.g., standards for software interactions with banks and tax authorities). Altogether, this has made the paths taken in this process to be largely national. In general, this process of digitalization is largely undocumented and untheorized in research despite its profound impact on practice. Against this backdrop, this chapter has a descriptive and forward-looking approach, documenting the case of how Swedish bookkeeping practices of small organizations became digitalized, which can work as a reference case for comparisons with other national contexts.
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Alrutz, Marie, et al.
(författare)
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Projektledning
- 2013
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Bok (populärvet., debatt m.m.)abstract
- Projektledning är ett yrke med egen certifiering. Det pågår en spännande utveckling inom området och det blir allt viktigare att hålla sig ajour med utvecklingen.Det övergripande målet med den här handboken är att vara en ständigt aktuell heltäckande bok om projektarbete. Innehållsmässigt täcker den både frågor som har med struktur och styrning att göra och frågor om ledning av människor och mänskliga processer i grupp. Kompetens inom projekt byggs av både kunskap och erfarenhet. Vi följer kontinuerligt aktuell forskning inom dessa områden och bjuder in intressanta forskare att medverka som författare. Vi skildrar verkliga projekt och låter erfarenheterna få plats, både de bästa erfarenheterna och de utmaningar som man tagit sig igenom.Handboken är levande och det innebär att artiklar tas bort för att ge plats för nya, i takt med att den uppdateras fortlöpande.
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| 29. |
- Alsanius, Beatrix, et al.
(författare)
-
Terroir Bjäre : en fallstudie
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vin är en relativ ny gröda i Sverige, i och med att den är beroende av en lång växtsäsong. Bjärehalvön (Båstads kommun) är känd för sin tidiga växtsäsong (t.ex. för odling av färskpotatis) och det bidrog till att idén att provodla vitvin där. Bröddarp som ligger 3 km ifrån halvöns västra kust föddes. Fyra lokaler (försöksytor, parceller) valdes och tre typer av markskötsel (öppen jord, marktäckning med folie, marktäckning med sten) testades under etableringsfasen i syfte att förbättra platsens förutsättningar. Det långsiktiga ursprungliga målet med försöksupplägget var att studera påverkan av olika markbehandlingar på druvmognaden och –kvaliteten. Fyra vitvinssorter (Ortega, Pinot gris, Siegerrebe och Solaris) provodlades. I föreliggande rapport redovisas olika definitioner för terroir. Platsens klimatiska förutsättningar (solens instrålningsvinkel, globalstrålning, lufttemperatur, graddagar, heliotermiskt och niktotermiskt index, nederbörd, marktemperatur) analyserades. Med undantag av marktemperaturen baserades de flesta klimatiska parametrar på en tioårsperiod, från 2004-2013. Utöver detta studerades dynamiken i halten organisk substans och kvävemineralisering. Vinplantornas tillväxt och utveckling samt förmåga att motstå kyla under vintern registrerades. Däremot går föreliggande observationsförsök inte in på frågor relaterade till markens vattenförhållande – detta på grund av forskningsfinansiella överväganden. En grov skattning avminimikraven för odling av vin är enligt Müller et al. (20) • Årsmedeltemperatur ≥ 9 °C • Vegetationstidens längd (period mellan sista vårfrost till första höstfrost) > 180 dagar • Medeltemperatur under vegetationsperioden (april-oktober) ≥ 13 °C • Medeltemperatur under årets varmaste månad ≥ 18 °C • Graddagar under vegetationsperioden > 1000 • Minst 1300 soltimmar med minst 200000 J cm-2 • lägsta vintertemperatur <-20 °C. Dessa hörnsten i skattningen tar inte hänsyn till samtliga biotiska och abiotiska faktorer och samspelen dem emellan. Detta är mycket viktigt att hålla i åtanke. Vår analys visar att årsmedeltemperaturen ≥ 9 °C enbart uppnåddes enbart under tre av tio år under perioden 2004-2013. Zenitvinkeln var som högst 57°. Vegetationsperiodens längd översteg nästan alltid 180 dagar med god marginal och medeltemperaturen under perioden april-oktober var 13.35 °C. Däremot uppnåddes enbart under sex av tio år en medeltemperatur ≥ 18 °C under årets varmaste månad (juli respektive augusti). Endast år 2006 klättrade antalet graddagar > 1000. Däremot låg den heliotermiska indexen vid gränsen av odlingslämplighet för vin (HI: 1502 ± 156), och den niktotermiska indexen, d.v.s. genomsnitt av lägsta nattemperatur under september månad (CI) på 11.6 ± 1.02 °C. Antal solskenstimmar under månaderna april till oktober låg i genomsnitt >1300, men vi har inget underlag vad gäller strålningsintensiteten. Därför kan detta krav inte avgöras. Relationen mellan solskenstimmar och graddagar är en viktig avkastningsbildande parameter; och antalet solskenstimmar var alltid större än antalet graddagar. Lägsta vintertemperatur under -20 °C registrerades vid inget tillfälle. Under observationsperioden var det nästan aldrig vindstilla; den dominanta vindhastigheten låg på 5-10 m s-1. Vinden blåste främst ur sydlig, sydvästlig och västlig riktning. Marktäckning påverkade inte marktemperaturen. På så sätt fastställdes inte heller några skillnader vad gäller dynamiken i organisk substans eller halten mineraliserat kväve (ammonium, nitrat), då prover togs i två markdjup (0-30 cm; 30-60 cm). Siegerrebe och Solaris visade den starkaste respektive svagaste tillväxten under första etableringsåret. Solaris acklimatiserade sig däremot bäst till kalla betingelser och visade starkaste härdighet. För Solaris noterades också den största stamdiametern efter andra odlingsåret, medan stamdiametern hos Siegerrebe var klenast. Att döma utifrån stamdiametern var vinsorternas tillväxt bäst på på yta 3.
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| 30. |
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| 31. |
- Andersson, Anders, et al.
(författare)
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A transcriptional timetable of autumn senescence
- 2004
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 5:4, s. R24-
-
Tidskriftsartikel (refereegranskat)abstract
- Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.
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| 32. |
- Andersson, Anders, 1983-, et al.
(författare)
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Co-simulation architecture with pedestrian, vehicle, and traffic simulators
- 2021
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Ingår i: Actes (IFSTTAR). - : Driving Simulation Association. ; , s. 181-184
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Konferensbidrag (refereegranskat)abstract
- Automated and connected traffic systems with cooperative functionality need effective testing. One way to enable such testing is to represent the current traffic environment by co-simulating different simulators using a communication layer between the simulators for cooperative functionality. With this approach, this paper presents a platform with its included simulators (vehicle, pedestrian, and traffic simulators), the used run-time infrastructure (RTI) for co-simulation, and the connection to the Unreal Engine based visual system for the simulators. The architecture was tested with two vehicle simulators (one autonomous bus and a truck), one pedestrian simulator, and one traffic simulator connected using a cloud-based service for the RTI.
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| 33. |
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| 34. |
- Askenmalm, Fredrika
(författare)
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Hur mjölk i tanken blir kronor på banken : Bondförnuftets rationalitet
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lantbrukare har under senare år ofta hörts framföra klagomål om att den administrativa bördan blivit allt tyngre vad gäller rapportering och ansökningar som ska göras till olika myndigheter. Tidigare forskning framställer det som att den administrativa bördan skulle kunna utsträckas till att också gälla redovisning, så som bokföring, kalkylering och budgetering. Detta då det beskrivs som att lantbrukare varken förstår eller använder redovisning för att sköta sitt lantbruk. Tidigare forskning tycks dock bortse från att lantbrukare ofta tillämpar en annan form av logik än den som förutsätts gälla inom redovisningsforskning. Det verkar också förutsättas att lantbrukarna ska kunna förstå och använda den redovisningsterminologi som finns inom forskningsvärlden trots att lantbrukarna ofta saknar utbildning inom redovisning. Mot denna bakgrund undersöker denna avhandling hur lantbrukare förstår och använder redovisning.Avhandlingen bygger på det grundläggande teoretiska perspektivet att se redovisning som ett språk för att på detta sätt förklara lantbrukarnas förståelse av redovisning. Avhandlingen bygger vidare på familjeföretagsforskning, speciellt socioemotional wealth (SEW), och beslutsteori för att förklara lantbrukarnas användning av redovisningsinformation.Den empiriska studien är inspirerad av grundad teori. Det empiriska materialet utgörs främst av intervjuer med mjölkbönder i Jönköpings län. Även intervjuer med rådgivare och bankmän och vissa sekundärdata har utgjort underlag för avhandlingen.Resultatet av undersökningen visar att lantbrukare har större kunskaper vad gäller redovisning än vad tidigare forskning indikerat. Delvis kan detta förklaras av att lantbrukare använder en annan terminologi än vad som vanligtvis används inom redovisningsforskning när de beskriver redovisning. Mjölkföretag drivs vanligen som familjeföretag och denna avhandling visar på en mycket stark familjeförankring i dessa företag. Det innebär att mjölkföretag ibland (speciellt vad gäller fastigheten) prioriterar annat än finansiella mål, vilket ofta kopplas samman med en intuitiv beslutsstil. Inom redovisning förutsätts generellt att finansiella mål är eftersträvansvärda. Lantbrukarnas sätt att se på redovisning påverkar också hur den används. Även om de förstår och använder redovisning är det inte säkert att den används på det mest vinstmaximerande sättet. I stället kan SEW vara det som prioriteras. Användning av redovisning anpassas efter den situation lantbrukaren befinner sig i. Vissa delar av redovisningen ses och förstås som speglingar av verkligheten eller som framåtriktade ledtrådar. När lantbrukare förstår redovisningen på så vis, uppfattas den som användbar för beslutsfattande. Andra delar av redovisningen ses som regelföljande, eller ibland till och med som helt frikopplad från själva verksamheten. Detta gäller framför allt redovisning till Skatteverket och Jordbruksverket. Dessa redovisningar används inte för beslut, men de är ändå rationellt utformade för att uppnå bästa möjliga utfall (skatteutjämning eller jordbruksstöd).
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| 35. |
- Attauabi, Mohamed, et al.
(författare)
-
Influence of Genetics, Immunity and the Microbiome on the Prognosis of Inflammatory Bowel Disease (IBD Prognosis Study) : the protocol for a Copenhagen IBD Inception Cohort Study
- 2022
-
Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:6, s. e055779-e055779
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Inflammatory bowel diseases (IBD), encompassing Crohn's disease and ulcerative colitis, are chronic, inflammatory diseases of the gastrointestinal tract. We have initiated a Danish population-based inception cohort study aiming to investigate the underlying mechanisms for the heterogeneous course of IBD, including need for, and response to, treatment.Methods and analysis: IBD Prognosis Study is a prospective, population-based inception cohort study of unselected, newly diagnosed adult, adolescent and paediatric patients with IBD within the uptake area of Hvidovre University Hospital and Herlev University Hospital, Denmark, which covers approximately 1 050 000 inhabitants (~20% of the Danish population). The diagnosis of IBD will be according to the Porto diagnostic criteria in paediatric and adolescent patients or the Copenhagen diagnostic criteria in adult patients. All patients will be followed prospectively with regular clinical examinations including ileocolonoscopies, MRI of the small intestine, validated patient-reported measures and objective examinations with intestinal ultrasound. In addition, intestinal biopsies from ileocolonoscopies, stool, rectal swabs, saliva samples, swabs of the oral cavity and blood samples will be collected systematically for the analysis of biomarkers, microbiome and genetic profiles. Environmental factors and quality of life will be assessed using questionnaires and, when available, automatic registration of purchase data. The occurrence and course of extraintestinal manifestations will be evaluated by rheumatologists, dermatologists and dentists, and assessed by MR cholangiopancreatography, MR of the spine and sacroiliac joints, ultrasonography of peripheral joints and entheses, clinical oral examination, as well as panoramic radiograph of the jaws. Fibroscans and dual-energy X-ray absorptiometry scans will be performed to monitor occurrence and course of chronic liver diseases, osteopenia and osteoporosis.Ethics and dissemination: This study has been approved by Ethics Committee of the Capital Region of Denmark (approval number: H-20065831). Study results will be disseminated through publication in international scientific journals and presentation at (inter)national conferences.
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| 36. |
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| 37. |
- Babst, Benjamin A, et al.
(författare)
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Local and systemic transcriptome responses to herbivory and jasmonic acid in Populus
- 2009
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Ingår i: The Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 5:3, s. 459-474
-
Tidskriftsartikel (refereegranskat)abstract
- We used DNA microarrays to examine local and systemic transcriptional responses to herbivory by gypsy moth larvae (GM) and exogenous jasmonic acid (JAtrt) in leaves of Populus nigra L. to identify candidate signaling and defense genes and also to examine primary metabolism, as might relate to tolerance of damage. GM and JAtrt altered expression of over 800 genes, most of which have putative roles in defense signaling, secondary metabolism, and primary metabolism. Additionally, numerous uncharacterized genes responded to herbivory, providing a rich resource for future studies. There was limited overlap (14%) between the responses to GM and JAtrt. GM did, however, result in strong upregulation of genes involved not only in JA biosynthesis but also abscisic acid biosynthesis and other signaling pathways. GM induced known resistance transcripts, including polyphenolic biosynthetic genes, proteinase inhibitors, and amino acid deaminases. According to GOStats pathway level analysis, GM altered primary metabolism, including aromatic amino acid biosynthesis, fatty acid β-oxidation, and carbohydrate and organic acid metabolism. These alterations may be related to increased demands for substrate for secondary metabolites or may serve a tolerance-related role. Responses were more intense locally in treated leaves than in untreated (systemic) leaves and systemic responses were mostly a subset of the genes induced locally. A stronger local response might be needed to cope with localized stresses and wound healing. Since Populus in general and this clone in particular are known for their systemic induced resistance, genes induced both locally and systemically may be the highest quality candidates for resistance.
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| 38. |
- Beer, Netta, et al.
(författare)
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A qualitative study on caretakers' perceived need of bed-nets after reduced malaria transmission in Zanzibar, Tanzania
- 2012
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Ingår i: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 12, s. 606-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The elimination of malaria in Zanzibar is highly dependent on sustained effective coverage of bed-nets to avoid malaria resurgence. The Health Belief Model (HBM) framework was used to explore the perceptions of malaria and bed-net use after a noticeable reduction in malaria incidence. Methods: Nineteen in-depth interviews were conducted with female and male caretakers of children under five in North A district, Zanzibar. Deductive content analysis was used to identify meaning units that were condensed, coded and assigned to pre-determined elements of the HBM. Results: Awareness of malaria among caretakers was high but the illness was now seen as easily curable and uncommon. In addition to the perceived advantage of providing protection against malaria, bed-nets were also thought to be useful for avoiding mosquito nuisance, especially during the rainy season when the malaria and mosquito burden is high. The discomfort of sleeping under a net during the hot season was the main barrier that interrupted consistent bed-net usage. The main cue to using a bed-net was high mosquito density, and children were prioritized when it came to bed-net usage. Caretakers had high perceived self-efficacy and did not find it difficult to use bed-nets. Indoor Residual Spraying (IRS), which was recognized as an additional means of mosquito prevention, was not identified as an alternative for bed-nets. A barrier to net ownership was the increasingly high cost of bed-nets. Conclusions: Despite the reduction in malaria incidence and the resulting low malaria risk perceptions among caretakers, the benefit of bed-nets as the most proficient protection against mosquito bites upholds their use. This, in combination with the perceived high self-efficacy of caretakers, supports bed-net usage, while seasonality interrupts consistent use. High effective coverage of bed-nets could be further improved by reinforcing the benefits of bed-nets, addressing the seasonal heat barrier by using nets with larger mesh sizes and ensuring high bed-net ownership rates through sustainable and affordable delivery mechanisms.
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| 39. |
- Bergstrom, Jens, et al.
(författare)
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Very High Cycle Fatigue of Two Ductile Iron Grades
- 2016
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 87:5, s. 614-621
-
Tidskriftsartikel (refereegranskat)abstract
- Two ductile iron grades, EN-GJS-600-3 a ferritic-pearlitic grade, and EN-GJS-600-10 a silicon strengthened ferritic nodular iron grade, are studied in the very high cycle fatigue range using a 20kHz ultrasonic test equipment. Fatigue strengths and SN-curves are achieved, and fracture surfaces and microstructures are investigated. The ferritic grade with higher ductility displays a lower fatigue strength at 10(8) load cycles than the ferritic-pearlitic grade, 142 and 167MPa, respectively. Examination of fracture surfaces shows that fatigue failures are controlled by micropores in both of the ductile iron grades, while the graphite nodule distributions do not seem to influence the difference in fatigue strengths. Prediction of the fatigue strengths, using a model for ductile iron proposed by Endo and Yanase, indicates a large potential for improvement in particular for the ferritic grade.
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| 40. |
- Bergwall, Andreas, 1972-, et al.
(författare)
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Teachers’ characterizations of challenging introductory and enrichment tasks
- 2022
-
Ingår i: CERME 12. - : European Society for Research in Mathematics Education.
-
Konferensbidrag (refereegranskat)abstract
- Developing tasks for use in mixed-ability classrooms presents teachers with several dilemmas. By making one such dilemma an explicit object of inquiry, this study aims to capture characteristics for challenging tasks suitable for introduction or enrichment. It is based on eight teachers’ collaborative and retrospective analysis of challenging tasks developed in a combined research and school development project. Among the results are the observation that introductory tasks should have an easy entry level and not require pre-knowledge of the upcoming concept, while an enrichment task should require relatively deep conceptual pre-knowledge. It is suggested that attention to seemingly contradictory features of introductory and enrichment tasks can fuel collaborative learning processes so that they include several important aspects of tasks aimed at challenging all students. Teachers’ verbalization of task characteristics is one outcome of such a process.
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| 41. |
- Bernardy, Jean-Philippe, 1978, et al.
(författare)
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A comparison of C++ concepts and Haskell type classes
- 2008
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Ingår i: ACM SIGPLAN Workshop on Generic Programming 2008. Victoria, Canada, 20th September 2008. - 9781605580609 ; , s. 37-48
-
Konferensbidrag (refereegranskat)abstract
- Earlier studies have introduced a list of high-level evaluation criteria to assess how well a language supports generic programming. Since each language that meets all criteria is considered generic, those criteria are not fine-grained enough to differentiate between two languages for generic programming.We refine these criteria into a taxonomy that capturesdifferences between type classes in Haskell and concepts inC++, and discuss which differences are incidental and whichones are due to other language features. The taxonomy allows for an improved understanding of language support for generic programming, and the comparison is useful for the ongoing discussions among language designers and users of both languages.
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Bylesjö, Max, et al.
(författare)
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Integrated analysis of transcript, protein and metabolite data to study lignin biosynthesis in hybrid aspen
- 2009
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 8:1, s. 199-210
-
Tidskriftsartikel (refereegranskat)abstract
- Tree biotechnology will soon reach a mature state where it will influence the overall supply of fiber, energy and wood products. We are now ready to make the transition from identifying candidate genes, controlling important biological processes, to discovering the detailed molecular function of these genes on a broader, more holistic, systems biology level. In this paper, a strategy is outlined for informative data generation and integrated modeling of systematic changes in transcript, protein and metabolite profiles measured from hybrid aspen samples. The aim is to study characteristics of common changes in relation to genotype-specific perturbations affecting the lignin biosynthesis and growth. We show that a considerable part of the systematic effects in the system can be tracked across all platforms and that the approach has a high potential value in functional characterization of candidate genes.
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| 46. |
- Bylesjö, Max, et al.
(författare)
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MASQOT : a method for cDNA microarray spot quality control.
- 2005
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 6, s. 250-
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundcDNA microarray technology has emerged as a major player in the parallel detection of biomolecules, but still suffers from fundamental technical problems. Identifying and removing unreliable data is crucial to prevent the risk of receiving illusive analysis results. Visual assessment of spot quality is still a common procedure, despite the time-consuming work of manually inspecting spots in the range of hundreds of thousands or more.ResultsA novel methodology for cDNA microarray spot quality control is outlined. Multivariate discriminant analysis was used to assess spot quality based on existing and novel descriptors. The presented methodology displays high reproducibility and was found superior in identifying unreliable data compared to other evaluated methodologies.ConclusionThe proposed methodology for cDNA microarray spot quality control generates non-discrete values of spot quality which can be utilized as weights in subsequent analysis procedures as well as to discard spots of undesired quality using the suggested threshold values. The MASQOT approach provides a consistent assessment of spot quality and can be considered an alternative to the labor-intensive manual quality assessment process.
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| 47. |
- Bylesjö, Max, et al.
(författare)
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MASQOT-GUI : spot quality assessment for the two-channel microarray platform
- 2006
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 22:20, s. 2554-2555
-
Tidskriftsartikel (refereegranskat)abstract
- MASQOT-GUI provides an open-source, platform-independent software pipeline for two-channel microarray spot quality control. This includes gridding, segmentation, quantification, quality assessment and data visualization. It hosts a set of independent applications, with interactions between the tools as well as import and export support for external software. The implementation of automated multivariate quality control assessment, which is a unique feature of MASQOT-GUI, is based on the previously documented and evaluated MASQOT methodology. Further abilities of the application are outlined and illustrated. AVAILABILITY: MASQOT-GUI is Java-based and licensed under the GNU LGPL. Source code and installation files are available for download at http://masqot-gui.sourceforge.net/
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| 48. |
- Bylesjö, Max, et al.
(författare)
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Orthogonal projections to latent structures as a strategy for microarray data normalization
- 2007
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 8:207
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundDuring generation of microarray data, various forms of systematic biases are frequently introduced which limits accuracy and precision of the results. In order to properly estimate biological effects, these biases must be identified and discarded.ResultsWe introduce a normalization strategy for multi-channel microarray data based on orthogonal projections to latent structures (OPLS); a multivariate regression method. The effect of applying the normalization methodology on single-channel Affymetrix data as well as dual-channel cDNA data is illustrated. We provide a parallel comparison to a wide range of commonly employed normalization methods with diverse properties and strengths based on sensitivity and specificity from external (spike-in) controls. On the illustrated data sets, the OPLS normalization strategy exhibits leading average true negative and true positive rates in comparison to other evaluated methods.ConclusionsThe OPLS methodology identifies joint variation within biological samples to enable the removal of sources of variation that are non-correlated (orthogonal) to the within-sample variation. This ensures that structured variation related to the underlying biological samples is separated from the remaining, bias-related sources of systematic variation. As a consequence, the methodology does not require any explicit knowledge regarding the presence or characteristics of certain biases. Furthermore, there is no underlying assumption that the majority of elements should be non-differentially expressed, making it applicable to specialized boutique arrays.
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| 49. |
- Cámara, Fernando, 1967-, et al.
(författare)
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Zinkgruvanite, Ba4Mn2+4Fe3+2(Si2O7)2(SO4)2O2(OH)2, a new ericssonite-group mineral from the Zinkgruvan Zn-Pb-Ag-Cu deposit, Askersund, Örebro County, Sweden.
- 2021
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Ingår i: European journal of mineralogy. - : Nicolaus Copernicus University Press. - 0935-1221 .- 1617-4011. ; 33:6, s. 659-673
-
Tidskriftsartikel (refereegranskat)abstract
- Zinkgruvanite, ideally Ba4Mn2+4Fe3+2(Si2O7)2(SO4)2O2(OH)2, is a new member of the ericssonite group, found in Ba-rich drill core samples from a sphalerite+galena- and diopside-rich metatuffite succession from the Zinkgruvan mine, Örebro county, Sweden. Zinkgruvanite is associated with massive baryte, barytocalcite, diopside and minor witherite, cerchiaraite-(Al) and sulfide minerals. It occurs as subhedral to euhedral flattened and elongated crystals up to 4 mm. It is almost black, semi-opaque with a dark brown streak. The luster is vitreous to sub-adamantine on crystal faces, resinous on fractures. The mineral is brittle with an uneven fracture. VHN100 = 539 and HMohs ~4½. In thin fragments, it is reddish-black, translucent and optically biaxial (+), 2Vz > 70°. Pleochroism is strong, deep brown-red (E ⊥ {001} cleavage) to olive-pale brown. Chemical point analyses by WDS-EPMA together with iron valencies determined from Mössbauer spectroscopy, yielded the empirical formula (based on 26 O+OH+F+Cl anions): (Ba4.02Na0.03)Σ4.05(Mn1.79Fe2+1.56Fe3+0.42Mg0.14Ca0.10Ni0.01Zn0.01)Σ4.03 (Fe3+1.74Ti0.20Al0.06)Σ2.00Si4(S1.61Si0.32P0.07)Σ1.99O24(OH1.63Cl0.29F0.08)Σ2.00. The mineral is triclinic, space group P–1, with unit-cell parameters a = 5.3982(1) Å, b = 7.0237(1) Å, c = 14.8108(4) Å, α = 98.256(2)º, β = 93.379(2)º, γ = 89.985(2)º and V = 554.75(2) Å3 for Z = 1. The eight strongest X-ray powder diffraction lines are [d Å (I%; hkl)]: 3.508 (70; 103), 2.980(70; 11–4), 2.814 (68; 1–22), 2.777 (70; 121), 2.699 (714; 200), 2.680 (68; 20–1), 2.125 (100; 124, 204), 2.107 (96; –221). The crystal structure (R1 = 0.0379 for 3204 reflections) is an array of TS (titanium silicate) blocks alternating with intermediate blocks. The TS blocks consist of HOH sheets (H = heteropolyhedral, O = octahedral) parallel to (001). In the O sheet, the Mn2+-dominant MO(1,2,3) sites give ideally Mn2+4 pfu. In the H sheet, the Fe3+-dominant MH sites and AP(1) sites give ideally Fe3+2Ba2 pfu. In the intermediate block, SO4 oxyanions and eleven coordinated Ba atoms give ideally 2 × SO4Ba pfu. Zinkgruvanite is related to ericssonite and ferro-ericssonite in having the same topology and type of linkage of layers in the TS block. Zinkgruvanite is also closely compositionally related to yoshimuraite, Ba4Mn4Ti2(Si2O7)2(PO4)2O2(OH)2, via the coupled heterovalent substitution 2 Ti4+ + 2 (PO4)3- →2 Fe3+ + 2 (SO4)2-, but presents a different type of linkage. The new mineral probably formed during a late stage of regional metamorphism of a Ba-enriched, syngenetic protolith, involving locally generated oxidized fluids of high salinity.
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| 50. |
- Cheng, Xiaoxiao, et al.
(författare)
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Structure and Interactions of the Human Programmed Cell Death 1 Receptor
- 2013
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 288:17, s. 11771-11785
-
Tidskriftsartikel (refereegranskat)abstract
- PD-1, a receptor expressed by T cells, B cells, and monocytes, is a potent regulator of immune responses and a promising therapeutic target. The structure and interactions of human PD-1 are, however, incompletely characterized. We present the solution nuclear magnetic resonance (NMR)-based structure of the human PD-1 extracellular region and detailed analyses of its interactions with its ligands, PD-L1 and PD-L2. PD-1 has typical immunoglobulin superfamily topology but differs at the edge of the GFCC' sheet, which is flexible and completely lacks a C '' strand. Changes in PD-1 backbone NMR signals induced by ligand binding suggest that, whereas binding is centered on the GFCC' sheet, PD-1 is engaged by its two ligands differently and in ways incompletely explained by crystal structures of mouse PD-1.ligand complexes. The affinities of these interactions and that of PD-L1 with the costimulatory protein B7-1, measured using surface plasmon resonance, are significantly weaker than expected. The 3-4-fold greater affinity of PD-L2 versus PD-L1 for human PD-1 is principally due to the 3-fold smaller dissociation rate for PD-L2 binding. Isothermal titration calorimetry revealed that the PD-1/PD-L1 interaction is entropically driven, whereas PD-1/PD-L2 binding has a large enthalpic component. Mathematical simulations based on the biophysical data and quantitative expression data suggest an unexpectedly limited contribution of PD-L2 to PD-1 ligation during interactions of activated T cells with antigen-presenting cells. These findings provide a rigorous structural and biophysical framework for interpreting the important functions of PD-1 and reveal that potent inhibitory signaling can be initiated by weakly interacting receptors.
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