| 1. |
- Abbasi, R., et al.
(författare)
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Characterization of the astrophysical diffuse neutrino flux using starting track events in IceCube
- 2024
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Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 2470-0010 .- 2470-0029. ; 110:2
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Tidskriftsartikel (refereegranskat)abstract
- A measurement of the diffuse astrophysical neutrino spectrum is presented using IceCube data collected from 2011-2022 (10.3 years). We developed novel detection techniques to search for events with a contained vertex and exiting track induced by muon neutrinos undergoing a charged-current interaction. Searching for these starting track events allows us to not only more effectively reject atmospheric muons but also atmospheric neutrino backgrounds in the southern sky, opening a new window to the sub-100 TeV astrophysical neutrino sky. The event selection is constructed using a dynamic starting track veto and machine learning algorithms. We use this data to measure the astrophysical diffuse flux as a single power law flux (SPL) with a best-fit spectral index of γ=2.58-0.09+0.10 and per-flavor normalization of φper-flavorAstro=1.68-0.22+0.19×10-18×GeV-1 cm-2 s-1 sr-1 (at 100 TeV). The sensitive energy range for this dataset is 3-550 TeV under the SPL assumption. This data was also used to measure the flux under a broken power law, however we did not find any evidence of a low energy cutoff.
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| 2. |
- Abbasi, R., et al.
(författare)
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Improved modeling of in-ice particle showers for IceCube event reconstruction
- 2024
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 19:6
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Tidskriftsartikel (refereegranskat)abstract
- The IceCube Neutrino Observatory relies on an array of photomultiplier tubes to detect Cherenkov light produced by charged particles in the South Pole ice. IceCube data analyses depend on an in-depth characterization of the glacial ice, and on novel approaches in event reconstruction that utilize fast approximations of photoelectron yields. Here, a more accurate model is derived for event reconstruction that better captures our current knowledge of ice optical properties. When evaluated on a Monte Carlo simulation set, the median angular resolution for in-ice particle showers improves by over a factor of three compared to a reconstruction based on a simplified model of the ice. The most substantial improvement is obtained when including effects of birefringence due to the polycrystalline structure of the ice. When evaluated on data classified as particle showers in the high-energy starting events sample, a significantly improved description of the events is observed.
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| 3. |
- Abbasi, R., et al.
(författare)
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Citizen science for IceCube: Name that Neutrino
- 2024
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Ingår i: European Physical Journal Plus. - 2190-5444. ; 139:6
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Tidskriftsartikel (refereegranskat)abstract
- Name that Neutrino is a citizen science project where volunteers aid in classification of events for the IceCube Neutrino Observatory, an immense particle detector at the geographic South Pole. From March 2023 to September 2023, volunteers did classifications of videos produced from simulated data of both neutrino signal and background interactions. Name that Neutrino obtained more than 128,000 classifications by over 1800 registered volunteers that were compared to results obtained by a deep neural network machine-learning algorithm. Possible improvements for both Name that Neutrino and the deep neural network are discussed.
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| 4. |
- Abbasi, R., et al.
(författare)
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Search for Continuous and Transient Neutrino Emission Associated with IceCube's Highest-energy Tracks: An 11 yr Analysis
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 964:1
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Tidskriftsartikel (refereegranskat)abstract
- IceCube alert events are neutrinos with a moderate-to-high probability of having astrophysical origin. In this study, we analyze 11 yr of IceCube data and investigate 122 alert events and a selection of high-energy tracks detected between 2009 and the end of 2021. This high-energy event selection (alert events + high-energy tracks) has an average probability of >= 0.5 of being of astrophysical origin. We search for additional continuous and transient neutrino emission within the high-energy events' error regions. We find no evidence for significant continuous neutrino emission from any of the alert event directions. The only locally significant neutrino emission is the transient emission associated with the blazar TXS 0506+056, with a local significance of 3 sigma, which confirms previous IceCube studies. When correcting for 122 test positions, the global p-value is 0.156 and compatible with the background hypothesis. We constrain the total continuous flux emitted from all 122 test positions at 100 TeV to be below 1.2 x 10-15 (TeV cm2 s)-1 at 90% confidence assuming an E -2 spectrum. This corresponds to 4.5% of IceCube's astrophysical diffuse flux. Overall, we find no indication that alert events in general are linked to lower-energetic continuous or transient neutrino emission.
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| 5. |
- Abbasi, R., et al.
(författare)
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Search for decoherence from quantum gravity with atmospheric neutrinos
- 2024
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Ingår i: Nature Physics. - 1745-2481 .- 1745-2473. ; 20:6, s. 913-920
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Tidskriftsartikel (refereegranskat)abstract
- Neutrino oscillations at the highest energies and longest baselines can be used to study the structure of spacetime and test the fundamental principles of quantum mechanics. If the metric of spacetime has a quantum mechanical description, its fluctuations at the Planck scale are expected to introduce non-unitary effects that are inconsistent with the standard unitary time evolution of quantum mechanics. Neutrinos interacting with such fluctuations would lose their quantum coherence, deviating from the expected oscillatory flavour composition at long distances and high energies. Here we use atmospheric neutrinos detected by the IceCube South Pole Neutrino Observatory in the energy range of 0.5-10.0 TeV to search for coherence loss in neutrino propagation. We find no evidence of anomalous neutrino decoherence and determine limits on neutrino-quantum gravity interactions. The constraint on the effective decoherence strength parameter within an energy-independent decoherence model improves on previous limits by a factor of 30. For decoherence effects scaling as E2, our limits are advanced by more than six orders of magnitude beyond past measurements compared with the state of the art. Interactions of atmospheric neutrinos with quantum-gravity-induced fluctuations of the metric of spacetime would lead to decoherence. The IceCube Collaboration constrains such interactions with atmospheric neutrinos.
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| 6. |
- Abbasi, R., et al.
(författare)
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Search for 10-1000 GeV Neutrinos from Gamma-Ray Bursts with IceCube
- 2024
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Ingår i: Astrophysical Journal. - : Institute of Physics (IOP). - 1538-4357 .- 0004-637X. ; 964:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a search for 10-1000 GeV neutrinos from 2268 gamma-ray bursts (GRBs) over 8 yr of IceCube-DeepCore data. This work probes burst physics below the photosphere where electromagnetic radiation cannot escape. Neutrinos of tens of giga electronvolts are predicted in sub-photospheric collision of free-streaming neutrons with bulk-jet protons. In a first analysis, we searched for the most significant neutrino-GRB coincidence using six overlapping time windows centered on the prompt phase of each GRB. In a second analysis, we conducted a search for a group of GRBs, each individually too weak to be detectable, but potentially significant when combined. No evidence of neutrino emission is found for either analysis. The most significant neutrino coincidence is for Fermi-GBM GRB bn 140807500, with a p-value of 0.097 corrected for all trials. The binomial test used to search for a group of GRBs had a p-value of 0.65 after all trial corrections. The binomial test found a group consisting only of GRB bn 140807500 and no additional GRBs. The neutrino limits of this work complement those obtained by IceCube at tera electronvolt to peta electronvolt energies. We compare our findings for the large set of GRBs as well as GRB 221009A to the sub-photospheric neutron-proton collision model and find that GRB 221009A provides the most constraining limit on baryon loading. For a jet Lorentz factor of 300 (800), the baryon loading on GRB 221009A is lower than 3.85 (2.13) at a 90% confidence level.
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| 7. |
- Abazajian, Kevork, et al.
(författare)
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CMB-S4 : Forecasting Constraints on Primordial Gravitational Waves
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 926:1
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Tidskriftsartikel (refereegranskat)abstract
- CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2–3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5σ, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Espinosa, Lisa, et al.
(författare)
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Reading others' social appraisals after viewing an aversive film online impacts mood but not intrusive memories
- 2023
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Ingår i: Journal of Anxiety Disorders. - : Elsevier. - 0887-6185 .- 1873-7897. ; 99
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to aversive footage online can affect our well-being, but to what extent does reading others' appraisals of this content modulate our affective responses? In a pre-registered online study (N = 170), we used a digital trauma film paradigm as an analogue for the naturalistic exposure to aversive visual content online. We investigated whether online social reappraisal about the film influenced acute affective responses and subsequent intrusive memories. First, we examined whether the digital trauma film paradigm induced similar affective responses as in-lab experiments (within-subjects; change in negative mood and intrusive memories of the film during seven days). Participants reported a negative mood change and experienced intrusive memories of the film, extending findings from in-lab experiments. Next, we tested a social reappraisal manipulation that provides written comments from (fictitious) previous participants (between-subjects; reading positive, negative, or no comments) modulated participants' affective responses. As predicted, relative to controls and negative comments, reading positive comments decreased negative mood. However, reading negative comments did not increase negative mood. Contrary to predictions, the social reappraisal manipulation did not modulate the number of intrusive memories. Findings suggest the benefit of positive social reappraisal for mitigating negative mood, but not intrusive memories following aversive film content online.
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| 14. |
- Knitza, J, et al.
(författare)
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Toward Earlier Diagnosis Using Combined eHealth Tools in Rheumatology: The Joint Pain Assessment Scoring Tool (JPAST) Project
- 2020
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Ingår i: JMIR mHealth and uHealth. - : JMIR Publications Inc.. - 2291-5222. ; 8:5, s. e17507-
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Tidskriftsartikel (refereegranskat)abstract
- Outcomes of patients with inflammatory rheumatic diseases have significantly improved over the last three decades, mainly due to therapeutic innovations, more timely treatment, and a recognition of the need to monitor response to treatment and to titrate treatments accordingly. Diagnostic delay remains a major challenge for all stakeholders. The combination of electronic health (eHealth) and serologic and genetic markers holds great promise to improve the current management of patients with inflammatory rheumatic diseases by speeding up access to appropriate care. The Joint Pain Assessment Scoring Tool (JPAST) project, funded by the European Union (EU) European Institute of Innovation and Technology (EIT) Health program, is a unique European project aiming to enable and accelerate personalized precision medicine for early treatment in rheumatology, ultimately also enabling prevention. The aim of the project is to facilitate these goals while at the same time, reducing cost for society and patients.
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| 15. |
- McKinley, A. W., et al.
(författare)
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DNA Sequence and Ancillary Ligand Modulate the Biexponential Emission Decay of Intercalated [Ru(L)2dppz]2+ Enantiomers
- 2012
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Ingår i: Chemistry - A European Journal. - : Wiley. - 1521-3765 .- 0947-6539. ; 18:47, s. 15142-15150
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Tidskriftsartikel (refereegranskat)abstract
- The bi-exponential emission decay of [Ru(L)2dppz]2+ (L=N,N'-diimine ligand) bound to DNA has been studied as a function of polynucleotide sequence, enantiomer, and nature of L (phenanthroline vs. bipyridine). The lifetimes (ti) and pre-exponential factors (ai) depend on all three parameters. With [poly(dA-dT)]2, the variation of ai with [Nu]/[Ru] has little dependence on L for ?-[Ru(L)2dppz]2+ but a substantial dependence for ?-[Ru(L)2dppz]2+. With [poly(dG-dC)]2, by contrast, the ?-enantiomer ai values depend strongly on the nature of L, whereas those of the ?-enantiomer are relatively unaffected. DNA-bound linked dimers show similar photophysical behaviour. The lifetimes are identified with two geometries of minor-groove intercalated [Ru(L)2dppz]2+, resulting in differential water access to the phenazine nitrogen atoms. Interplay of cooperative and anti-cooperative binding resulting from complexcomplex and complexDNA interactions is responsible for the observed variations of ai with binding ratio. [Ru(phen)2dppz]2+ emission is quenched by guanosine in DMF, which may further rationalise the shorter lifetimes observed with guanine-rich DNA.
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| 16. |
- McKinley, A. W., et al.
(författare)
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Environmental effects on the photophysics of transition metal complexes with dipyrido 2,3-a:3 ',2 '-c phenazine (dppz) and related ligands
- 2011
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Ingår i: Coordination Chemistry Reviews. - : Elsevier BV. - 0010-8545. ; 255:21-22, s. 2676-2692
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Tidskriftsartikel (refereegranskat)abstract
- This review primarily covers studies of ruthenium(II) complexes with the dppz (dipyrido[2,3-a:3',2'-c]phenazine) ligand; in solution, in polymers and surfactant/lipid media, and when bound to DNA. Related studies with other transition metals, and with extended ligands that can form bimetallic as well as monometallic complexes are discussed. The review focuses on photophysics of these complexes with particular attention devoted to the nature of the excited states that give rise to emission, their dependence on solvent environment, and the behavior of the complexes as luminescent probes for DNA.
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| 17. |
- McKinley, A. W., et al.
(författare)
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Sensitivity of Ru(phen)(2)dppz (2+) light switch emission to ionic strength, temperature, and DNA sequence and conformation
- 2013
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 42:11, s. 4081-4090
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Tidskriftsartikel (refereegranskat)abstract
- The luminescence of DNA-bound [Ru(phen)(2)dppz](2+) is shown to be highly sensitive to environmental conditions such as ionic strength, temperature, and the sequence and secondary structure of the nucleic acid, although not to bulky DNA substituents in the major groove. Each enantiomer has two characteristic lifetimes with any polynucleotide and their relative amplitudes vary as a function of binding ratio. For [poly(dA-dT)](2) as a model sequence, the longer lifetime for Delta-[Ru(phen)(2)dppz](2+) has been assigned to canted intercalation of the complex and the shorter lifetime is ascribed to symmetric intercalation. At a fixed binding ratio, the longer lifetime amplitude increases with increasing ionic strength, without significant change in lifetimes. Increasing temperature has a similar effect, but also affects lifetimes. In general, emission is strongest with AT-rich polynucleotides and with higher-order secondary structures, with intensity increasing as single-stranded
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| 18. |
- Ratilainen, Tommi, 1970, et al.
(författare)
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Thermodynamics of sequence-specific binding of PNA to DNA
- 2000
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 39:26, s. 7781-7791
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Tidskriftsartikel (refereegranskat)abstract
- For further characterization of the hybridization properties of peptide nucleic acids (PNAs), the thermodynamics of hybridization of mixed sequence PNA-DNA duplexes have been studied. We have characterized the binding of PNA to DNA in terms of binding affinity (perfectly matched duplexes) and sequence specificity of binding (singly mismatched duplexes) using mainly absorption hypochromicity melting curves and isothermal titration calorimetry. For perfectly sequence-matched duplexes of varying lengths (6-20 bp), the average free energy of binding (Delta G degrees) was determined to be -6.5 +/- 0.3 kT mol(-1) bp(-1), corresponding to a microscopic binding constant of about 14 M-1 bp(-1). A variety of single mismatches were introduced in 9- and 12-mer PNA-DNA duplexes. Melting temperatures (T-m) of 9- and 12-mer PNA-DNA duplexes with a single mismatch dropped typically 15-20 degrees C relative to that of the perfectly matched sequence with a corresponding free energy penalty of about 15 kT mol(-1) bp(-1). The average cost of a single mismatch is therefore estimated to be on the order of or larger than the gain of two matched base pairs, resulting in an apparent binding constant of only 0.02 M-1 per mismatch. The impact of a mismatch was found to be dependent on the neighboring base pairs. To a first approximation, increasing the stability of the surrounding region, i.e., the distribution of A.T and G.C base pairs, decreases the effect of the introduced mismatch.
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