| 1. |
- Aad, G, et al.
(author)
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- 2015
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swepub:Mat__t
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| 2. |
- Schael, S, et al.
(author)
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Precision electroweak measurements on the Z resonance
- 2006
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Research review (peer-reviewed)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 3. |
- Schael, S., et al.
(author)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Research review (peer-reviewed)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Buchanan, E. M., et al.
(author)
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The Psychological Science Accelerator's COVID-19 rapid-response dataset
- 2023
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In: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 10:1
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Journal article (peer-reviewed)abstract
- In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data.
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| 6. |
- Olalde, I., et al.
(author)
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The Beaker phenomenon and the genomic transformation of northwest Europe
- 2018
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 555:7695, s. 190-196
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Journal article (peer-reviewed)abstract
- From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Vinko, S. M., et al.
(author)
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Electronic Structure of an XUV Photogenerated Solid-Density Aluminum Plasma
- 2010
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 104:22, s. 225001-
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Journal article (peer-reviewed)abstract
- By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.
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| 11. |
- Allentoft, M. E., et al.
(author)
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Population genomics of Bronze Age Eurasia
- 2015
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 522:7555
-
Journal article (peer-reviewed)abstract
- The Bronze Age of Eurasia (around 3000-1000 BC) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought.
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| 12. |
- Nelson, A. J., et al.
(author)
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Soft x-ray free electron laser microfocus for exploring matter under extreme conditions
- 2009
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In: Optics Express. - 1094-4087. ; 17:20, s. 18271-18278
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Journal article (peer-reviewed)abstract
- We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) -PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of <= 1 mu m. Observations were correlated with simulations of best focus to provide further relevant information.
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| 13. |
- Gaffney, K J, et al.
(author)
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Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb
- 2005
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 95:12
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Journal article (peer-reviewed)abstract
- The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotropy indicates that the initially generated fluid differs significantly from the equilibrium liquid.
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| 14. |
- Hajkova, V., et al.
(author)
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X-ray laser-induced ablation of lead compounds
- 2011
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In: DAMAGE TO VUV, EUV, AND X-RAY OPTICS III. - : SPIE.
-
Conference paper (peer-reviewed)abstract
- The recent commissioning of a X-ray free-electron laser triggered an extensive research in the area of X-ray ablation of high-Z, high-density materials. Such compounds should be used to shorten an effective attenuation length for obtaining clean ablation imprints required for the focused beam analysis. Compounds of lead (Z=82) represent the materials of first choice. In this contribution, single-shot ablation thresholds are reported for PbWO(4) and PbI(2) exposed to ultra-short pulses of extreme ultraviolet radiation and X-rays at FLASH and LCLS facilities, respectively. Interestingly, the threshold reaches only 0.11 J/cm(2) at 1.55 nm in lead tungstate although a value of 0.4 J/cm(2) is expected according to the wavelength dependence of an attenuation length and the threshold value determined in the XUV spectral region, i.e., 79 mJ/cm(2) at a FEL wavelength of 13.5 nm. Mechanisms of ablation processes are discussed to explain this discrepancy. Lead iodide shows at 1.55 nm significantly lower ablation threshold than tungstate although an attenuation length of the radiation is in both materials quite the same. Lower thermal and radiation stability of PbI(2) is responsible for this finding.
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| 15. |
- Thomas, H., et al.
(author)
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Explosions of Xenon Clusters in Ultraintense Femtosecond X-Ray Pulses from the LCLS Free Electron Laser
- 2012
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 108:13
-
Journal article (peer-reviewed)abstract
- Explosions of large Xe clusters (< N > similar to 11 000) irradiated by femtosecond pulses of 850 eV x-ray photons focused to an intensity of up to 1017 W/cm(2) from the Linac Coherent Light Source were investigated experimentally. Measurements of ion charge-state distributions and energy spectra exhibit strong evidence for the formation of a Xe nanoplasma in the intense x-ray pulse. This x-ray produced Xe nanoplasma is accompanied by a three-body recombination and hydrodynamic expansion. These experimental results appear to be consistent with a model in which a spherically exploding nanoplasma is formed inside the Xe cluster and where the plasma temperature is determined by photoionization heating.
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| 16. |
- Barty, A., et al.
(author)
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Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements
- 2012
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In: Nature Photonics. - 1749-4885 .- 1749-4893. ; 6:1, s. 35-40
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Journal article (peer-reviewed)abstract
- X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis1. For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been predicted that pulses as short as 10 fs may be required to acquire atomic-resolution structural information1, 2, 3, 4. Here, we describe a mechanism unique to ultrafast, ultra-intense X-ray experiments that allows structural information to be collected from crystalline samples using high radiation doses without the requirement for the pulse to terminate before the onset of sample damage. Instead, the diffracted X-rays are gated by a rapid loss of crystalline periodicity, producing apparent pulse lengths significantly shorter than the duration of the incident pulse. The shortest apparent pulse lengths occur at the highest resolution, and our measurements indicate that current X-ray free-electron laser technology5 should enable structural determination from submicrometre protein crystals with atomic resolution.
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| 17. |
- Lindenberg, AM, et al.
(author)
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Atomic-scale visualization of inertial dynamics
- 2005
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In: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 308:5720, s. 392-395
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Journal article (peer-reviewed)abstract
- The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.
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| 18. |
- Patterson, Nick, et al.
(author)
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Large-scale migration into Britain during the Middle to Late Bronze Age
- 2022
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; , s. 588-594
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Journal article (peer-reviewed)abstract
- Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000 and 875 BC, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain's independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period.
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| 19. |
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| 20. |
- Vinko, S. M., et al.
(author)
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Time-Resolved XUV Opacity Measurements of Warm Dense Aluminum
- 2020
-
In: Physical Review Letters. - : American Physical Society. - 1079-7114 .- 0031-9007. ; 124:22
-
Journal article (peer-reviewed)abstract
- The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order of the Fermi energy. Plasma heating and opacity enhancement are observed on ultrafast timescales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm dense matter.
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| 21. |
- Andreasson, Jakob, et al.
(author)
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Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser
- 2011
-
In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1539-3755 .- 1550-2376. ; 83:1, s. 016403-
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Journal article (peer-reviewed)abstract
- Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 1017 W/cm2 were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 1016 W/cm2. This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.
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| 22. |
- Aquila, A., et al.
(author)
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The linac coherent light source single particle imaging road map
- 2015
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In: Structural Dynamics. - : AIP Publishing. - 2329-7778. ; 2:4
-
Journal article (peer-reviewed)abstract
- Intense femtosecond x-ray pulses from free-electron laser sources allow the imag-ing of individual particles in a single shot. Early experiments at the Linac CoherentLight Source (LCLS) have led to rapid progress in the field and, so far, coherentdiffractive images have been recorded from biological specimens, aerosols, andquantum systems with a few-tens-of-nanometers resolution. In March 2014, LCLSheld a workshop to discuss the scientific and technical challenges for reaching theultimate goal of atomic resolution with single-shot coherent diffractive imaging. This paper summarizes the workshop findings and presents the roadmap towardreaching atomic resolution, 3D imaging at free-electron laser sources.
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| 23. |
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| 24. |
- Carneiro, Clarissa F. D., et al.
(author)
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Comparing quality of reporting between preprints and peer-reviewed articles in the biomedical literature
- 2020
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In: RESEARCH INTEGRITY AND PEER REVIEW. - : BMC. - 2058-8615. ; 5:1
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Journal article (peer-reviewed)abstract
- Background Preprint usage is growing rapidly in the life sciences; however, questions remain on the relative quality of preprints when compared to published articles. An objective dimension of quality that is readily measurable is completeness of reporting, as transparency can improve the reader's ability to independently interpret data and reproduce findings. Methods In this observational study, we initially compared independent samples of articles published in bioRxiv and in PubMed-indexed journals in 2016 using a quality of reporting questionnaire. After that, we performed paired comparisons between preprints from bioRxiv to their own peer-reviewed versions in journals. Results Peer-reviewed articles had, on average, higher quality of reporting than preprints, although the difference was small, with absolute differences of 5.0% [95% CI 1.4, 8.6] and 4.7% [95% CI 2.4, 7.0] of reported items in the independent samples and paired sample comparison, respectively. There were larger differences favoring peer-reviewed articles in subjective ratings of how clearly titles and abstracts presented the main findings and how easy it was to locate relevant reporting information. Changes in reporting from preprints to peer-reviewed versions did not correlate with the impact factor of the publication venue or with the time lag from bioRxiv to journal publication. Conclusions Our results suggest that, on average, publication in a peer-reviewed journal is associated with improvement in quality of reporting. They also show that quality of reporting in preprints in the life sciences is within a similar range as that of peer-reviewed articles, albeit slightly lower on average, supporting the idea that preprints should be considered valid scientific contributions.
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| 25. |
- Chalupsky, J., et al.
(author)
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Characteristics of focused soft X-ray free-electron laser beam determined by ablation of organic molecular solids
- 2007
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In: Optics Express. - 1094-4087. ; 15:10, s. 6036-6043
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Journal article (peer-reviewed)abstract
- A linear accelerator based source of coherent radiation, FLASH (Free-electron LASer in Hamburg) provides ultra-intense femtosecond radiation pulses at wavelengths from the extreme ultraviolet (XUV; lambda< 100nm) to the soft X-ray (SXR; lambda<30nm) spectral regions. 25-fs pulses of 32-nm FLASH radiation were used to determine the ablation parameters of PMMA - poly ( methyl methacrylate). Under these irradiation conditions the attenuation length and ablation threshold were found to be (56.9 +/- 7.5) nm and similar to 2 mJ center dot cm(-2), respectively. For a second wavelength of 21.7 nm, the PMMA ablation was utilized to image the transverse intensity distribution within the focused beam at mu m resolution by a method developed here.
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| 26. |
- Chalupsky, J, et al.
(author)
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Non-thermal desorption/ablation of molecular solids induced by ultra-short soft x-ray pulses
- 2009
-
In: Optics Express. - 1094-4087. ; 17:1, s. 208-217
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Journal article (peer-reviewed)abstract
- We report the first observation of single-shot soft x-ray laser induced desorption occurring below the ablation threshold in a thin layer of poly ( methyl methacrylate) - PMMA. Irradiated by the focused beam from the Free-electron LASer in Hamburg ( FLASH) at 21.7nm, the samples have been investigated by atomic-force microscope (AFM) enabling the visualization of mild surface modifications caused by the desorption. A model describing non-thermal desorption and ablation has been developed and used to analyze single-shot imprints in PMMA. An intermediate regime of materials removal has been found, confirming model predictions. We also report below-threshold multiple-shot desorption of PMMA induced by high-order harmonics (HOH) at 32nm. Short-time exposure imprints provide sufficient information about transverse beam profile in HOH's tight focus whereas long-time exposed PMMA exhibits radiation-initiated surface hardening making the beam profile measurement infeasible. (C) 2008 Optical Society of America
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| 27. |
- Fritz, D. M., et al.
(author)
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Ultrafast bond softening in bismuth : Mapping a solid's interatomic potential with X-rays
- 2007
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 315:5812, s. 633-636
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Journal article (peer-reviewed)abstract
- Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high excitation densities, the interatomic forces that bind solids and determine many of their properties can be substantially altered. Here, we present the detailed mapping of the carrier density-dependent interatomic potential of bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques that use a high-brightness linear electron accelerator-based x-ray source with pulse-by-pulse timing reconstruction for femtosecond resolution, allowing quantitative characterization of the interatomic potential energy surface of the highly excited solid.
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| 28. |
- Gabrysch, Markus, et al.
(author)
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Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses
- 2008
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:6
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Journal article (peer-reviewed)abstract
- Secondary electron cascades were measured in high purity single-crystalline chemical vapor deposition (CVD) diamond, following exposure to ultrashort hard x-ray pulses (140 fs full width at half maximum, 8.9 keV energy) from the Sub-Picosecond Pulse Source at the Stanford Linear Accelerator Center. We report measurements of the pair creation energy and of drift mobility of carriers in two CVD diamond crystals. This was done for the first time using femtosecond x-ray excitation. Values for the average pair creation energy were found to be 12.17 +/- 0.57 and 11.81 +/- 0.59 eV for the two crystals, respectively. These values are in good agreement with recent theoretical predictions. The average drift mobility of carriers, obtained by the best fit to device simulations, was mu(h)= 2750 cm(2)/V s for holes and was mu(e)= 2760 cm(2) / V s for electrons. These mobility values represent lower bounds for charge mobilities due to possible polarization of the samples. The results demonstrate outstanding electric properties and the enormous potential of diamond in ultrafast x-ray detectors.
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| 29. |
- Gordon, E.H.J., Sjögren, T., Löfqvist, M., Richter, C.D., Allen, J.W.A., Higham, C.W., Hajdu, J., Fülöp, V., Ferguson, S.J.
(author)
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Structure and Kinetic Properties of Paracoccus pantotrophus Cytochrome cd1 Nitrite Reductase with the d1 Heme Active Site Ligand Tyrosine 25 Replaced by Serine.
- 2003
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In: J. Biol. Chem.. ; 278, s. 11773-11781
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Journal article (peer-reviewed)
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| 30. |
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| 31. |
- Hajdu, Flora, et al.
(author)
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Cash transfers for sustainable rural livelihoods? Examining the long-term productive effects of the Child Support Grant in South Africa
- 2020
-
In: World Development Perspectives. - : Elsevier BV. - 2452-2929 .- 2468-0532. ; 19
-
Journal article (peer-reviewed)abstract
- Cash transfers have received increased scholarly and policy attention, as a means of reducing poverty in the global South. While cash transfers are primarily intended to prevent impoverishment and deprivation, several studies suggest they can have 'productive' impacts, contributing to building sustainable livelihoods. However, pilot projects of unconditional cash transfers have often been too brief or too recent to determine how small, but regular, transfers can improve rural livelihoods over time. This paper explores potential long-term productive effects of cash transfers on rural household's livelihoods. This is done through revisiting, after 14 years, all (273) households in two South African villages included in an extensive livelihood and asset survey in 2002. That survey predated the phasing in of the Child Support Grant (CSG), targeted at impoverished children. When re-surveyed in 2016, some households had cumulatively received significant, while others little or no CSG income. Multivariate regression analysis shows how households that received more CGS income were more likely to invest in productive assets (e.g. small ploughs), and engage in poultry, staple crop and vegetable production. We also found a statistically significant correlation between CSG incomes and growing a larger variety of crops, in an environment generally marked by deagrarianization. However, correlations between receiving more CSG and employment or engagement in informal small-scale trade were not significant. We use data from interviews and observations to explain these processes further. Compared with the paucity of outcomes from other concurrent and costly development interventions in the focal villages, cash transfers have improved livelihoods and living conditions significantly. However, the structural and contextual factors that cause and reproduce poverty remain unaltered, limiting the effects of comparatively small cash transfers. While we show that the cash transfers generate productive livelihood-enhancing effects, they remain insufficient to lift most households out of poverty without further structural changes and developmental interventions. © 2020 The Authors
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| 32. |
- Hajdu, J, et al.
(author)
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Analyzing protein functions in four dimensions
- 2000
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In: NATURE STRUCTURAL BIOLOGY. - : NATURE AMERICA INC. ; 7:11, s. 1006-1012
-
Review (other academic/artistic)abstract
- Time-resolved structural studies on biomolecular function are coming of age. Focus has shifted from studies on 'systems of opportunities' to a more problem-oriented approach, addressing significant questions in biology and chemistry. An important step in
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| 33. |
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| 34. |
- Iwan, Bianca S, et al.
(author)
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TOF-OFF : A method for determining focal positions in tightly focused free-electron laser experiments by measurement of ejected ions
- 2011
-
In: High Energy Density Physics. - : Elsevier BV. - 1574-1818. ; 7:4, s. 336-342
-
Journal article (peer-reviewed)abstract
- Pulse intensities greater than 1017 Watt/cm2 were reached at the FLASH soft X-ray laser in Hamburg, Germany, using an off-axis parabolic mirror to focus 15 fs pulses of 5–70 μJ energy at 13.5 nm wavelength to a micron-sized spot. We describe the interaction of such pulses with niobium and vanadium targets and their deuterides. The beam produced craters in the solid targets, and we measured the kinetic energy of ions ejected from these craters. Ions with several keV kinetic energy were observed from craters approaching 5 μm in depth when the sample was at best focus. We also observed the onset of saturation in both ion acceleration and ablation with pulse intensities exceeding 1016 W/cm2, when the highest detected ion energies and the crater depths tend to saturate with increasing intensity. A general difficulty in working with micron and sub-micron focusing optics is finding the exact focus of the beam inside a vacuum chamber. Here we propose a direct method to measure the focal position to a resolution better than the Rayleigh length. The method is based on the correlation between the energies of ejected ions and the physical dimensions of the craters. We find that the focus position can be quickly determined from the ion time-of-flight (TOF) data as the target is scanned through the expected focal region. The method does not require external access to the sample or venting the vacuum chamber. Profile fitting employed to analyze the TOF data can extend resolution beyond the actual scanning step size.
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| 35. |
- Jones, Benedict C, et al.
(author)
-
To which world regions does the valence-dominance model of social perception apply?
- 2021
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In: Nature Human Behaviour. - : Springer Science and Business Media LLC. - 2397-3374. ; 5:1, s. 159-169
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Journal article (peer-reviewed)abstract
- Over the past 10 years, Oosterhof and Todorov's valence-dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear whether these findings apply to other regions. We addressed this question by replicating Oosterhof and Todorov's methodology across 11 world regions, 41 countries and 11,570 participants. When we used Oosterhof and Todorov's original analysis strategy, the valence-dominance model generalized across regions. When we used an alternative methodology to allow for correlated dimensions, we observed much less generalization. Collectively, these results suggest that, while the valence-dominance model generalizes very well across regions when dimensions are forced to be orthogonal, regional differences are revealed when we use different extraction methods and correlate and rotate the dimension reduction solution. PROTOCOL REGISTRATION: The stage 1 protocol for this Registered Report was accepted in principle on 5 November 2018. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.7611443.v1 .
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- Lloyd, MD, et al.
(author)
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Studies on the active site of deacetoxycephalosporin C synthase
- 1999
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In: JOURNAL OF MOLECULAR BIOLOGY. - : ACADEMIC PRESS LTD. - 0022-2836. ; 287:5, s. 943-960
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Journal article (peer-reviewed)abstract
- The Fe(II) and 2-oxogolutarate-dependent dioxygenase deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus was expressed at ca 25% of total soluble protein in Escherichia coli and purified by an efficient large-scale procedure. Purified
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- Sjogren, T, et al.
(author)
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The structure of an alternative form of Paracoccus pantotrophus cytochrome cd(1) nitrite reductase
- 2001
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In: JOURNAL OF BIOLOGICAL CHEMISTRY. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 0021-9258. ; 276:31, s. 29450-29455
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Journal article (peer-reviewed)abstract
- Cytochrome ed(1) nitrite reductase is a bifunctional enzyme, which can catalyze the I-electron reduction of nitrite to nitric oxide and the 4-electron reduction of dioxygen to water. Here we describe the structure of reduced nitrite reductase, crystallize
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- Sokolowski-Tinten, Klaus, et al.
(author)
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Short-pulse Laser Induced Transient Structure Formation and Ablation Studied with Time-resolved Coherent XUV-scattering
- 2010
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In: INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010. - : AIP. ; , s. 373-379
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Conference paper (peer-reviewed)abstract
- The structural dynamics of short-pulse laser irradiated surfaces and nano-structures has been studied with nm spatial and ultrafast temporal resolution by means of single-shot coherent XUV-scattering techniques. The experiments allowed us to time-resolve the formation of laser-induced periodic surface structures, and to follow the expansion and disintegration of nano-objects during laser ablation.
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- Valegard, K, et al.
(author)
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Structure of a cephalosporin synthase
- 1998
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In: NATURE. - : MACMILLAN MAGAZINES LTD. - 0028-0836. ; 394:6695, s. 805-809
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Journal article (peer-reviewed)abstract
- Penicillins and cephalosporins are among the most widely used therapeutic agents. These antibiotics are produced from fermentation-derived materials as their chemical synthesis is not commercially viable. Unconventional steps in their biosynthesis are cat
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