441 research outputs found
Allometric scaling of thermal infrared emitted from UK cities and its relation to urban form
As a result of differences in heat absorption and release between urban and rural landscapes, cities develop a climate different from their surroundings. The rise in global average surface temperature and high rates of urbanization, make it important to understand the energy balance of cities, including whether any energy-balance-related patterns emerge as a function of city size. In this study, images from the Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite instrument, covering the period between 2000 and 2017, were sampled to examine the seasonal (winter and summer) night-time clear-sky upwelling long-wave energy for 35 UK cities. Total (area-summed) emitted energy per overpass per city is shown to correlate closely (R2 â„ 0.79) with population on a log-log âallometryâ plot. The production of emitted energy from the larger cities is smaller than would be produced from a constellation of smaller cities housing the same population. The mean allometry slope over all overpasses sampled is 0.84±0.06, implying an âeconomy (or parsimony) of scaleâ (i.e., a less-than-proportional increase) of about 21% (i.e. 100(2-100.84log(2))) for each doubling of city population. City area shows a very similar economy of scale, so that the scaling of night-time emitted energy with urban area is close to linear (1.0±0.05). This linearity with area indicates that the urban forms used in UK cities to accommodate people more efficiently per unit area as the urban population grows, do not have a large effect on the thermal output per unit area in each city. Although often appearing superficially very different, UK cities appear to be similar in terms of the components of urban form that dictate thermal properties. The difference between the scaling of the heat source and literature reports of the scaling of urban-rural air (or surface) temperature difference is very marked, suggesting that the other factors affecting the temperature difference act to decrease strongly its scaling with population
Hyphal Orientation of Candida albicans Is Regulated by a Calcium-Dependent Mechanism
SummaryEukaryotic cells from fungal hyphae to neurites that grow by polarized extension must coordinate cell growth and cell orientation to enable them to exhibit growth tropisms and to respond to relevant environmental cues. Such cells generally maintain a tip-high Ca2+ cytoplasmic gradient, which is correlated with their ability to exhibit polarized tip growth and to respond to growth-directing extracellular signals [1â5]. In yeast and other fungi, the polarisome, exocyst, Arp2/3, and Spitzenkörper protein complexes collectively orchestrate tip growth and cell polarity, but it is not clear whether these molecular complexes also regulate cell orientation or whether they are influenced by cytoplasmic Ca2+ gradients. Hyphae of the human pathogenic fungus Candida albicans reorient their growth axis in response to underlying surface topography (thigmotropism) [6] and imposed electric fields (galvanotropism) [7]. The establishment and maintenance of directional growth in relation to these environmental cues was Ca2+ dependent. Tropisms were attenuated in media containing low Ca2+, or calcium-channel blockers, and in mutants where calcium channels or elements of the calcium signaling pathway were deleted. Therefore galvanotropism and thigmotropism may both be mediated by localized Ca2+ influx at sites of polarized growth via Ca2+ channels that are activated by appropriate environmental signals
Cheater, cheater, pumpkin eater: The dark triad, attitudes towards doping, and cheating behavior among athletes
We examined the relationships between the Dark Triad personality traits (Machiavellianism, narcissism, and psychopathy), attitudes towards doping, and cheating behavior among athletes. One-hundred and sixty-four athletes completed a questionnaire that assessed the Dark Triad and their attitudes towards doping. Following this, athletes completed a matrix solving task within a specific time limit. Participants were told they would receive a financial reward for the total number matrices they could solve, but only 13 of the 20 matrices were solvable. This provided the incentive and an opportunity for the athletes to cheat. All three Dark Triad personality traits correlated positively with attitudes towards doping and cheating behavior. In regression analyses, psychopathy emerged as a significant positive predictor of attitudes towards doping, and narcissism emerged as a significant positive predictor of cheating behavior. Attitudes towards doping correlated positively with cheating behavior. The Dark Triad appears to be important in relation to both attitudes towards doping and cheating behavior among athletes. In addition, our findings illustrate that favorable attitudes towards doping were linked with actual cheating among athletes. National Anti-Doping Organizations, sports federations, and coaches could assess athletesâ Dark Triad scores and attitudes towards doping in order to identify who may be more likely to cheat
Coulomb Gauge QCD, Confinement, and the Constituent Representation
Quark confinement and the genesis of the constituent quark model are examined
in nonperturbative QCD in Coulomb gauge. We employ a self-consistent method to
construct a quasiparticle basis and to determine the quasiparticle interaction.
The results agree remarkably well with lattice computations. They also
illustrate the mechanism by which confinement and constituent quarks emerge,
provide support for the Gribov-Zwanziger confinement scenario, clarify several
perplexing issues in the constituent quark model, and permit the construction
of an improved model of low energy QCD.Comment: 43 pages, 14 figures, revtex, uses psfig.st
Railway infrastructure asset management: the whole-system life cost analysis
Delivering the railway infrastructure whose functionality is sustainable and uncompromised in terms of safety and availability under ever decreasing budget constraints is a great challenge. The successful accomplishment of this task relies on the effective management of individual assets within a wider whole system perspective. This is a highly complex decision-making task where mathematical models are required to enable well-informed choices. In this study, a novel modelling framework is proposed for performing the whole system lifecycle cost analysis. The framework is based on two models: railway network performance and costs. Using the former model investigations of the effects of decisions can be carried out for the individual asset and the whole system. A Petri net modelling technique is used to construct the model. A form of Monte Carlo simulation is then used to obtain model results. The infrastructure performance model is then integrated with the cost model to perform the lifecycle cost analysis. A superstructure example is presented to demonstrate the application of the approach. The results show that taking into account interdependencies among the intervention activities greatly influences, not only the performance of the infrastructure, but also its lifecycle costs and thus should be included in the cost analysis
Magnetic fields in supernova remnants and pulsar-wind nebulae
We review the observations of supernova remnants (SNRs) and pulsar-wind
nebulae (PWNe) that give information on the strength and orientation of
magnetic fields. Radio polarimetry gives the degree of order of magnetic
fields, and the orientation of the ordered component. Many young shell
supernova remnants show evidence for synchrotron X-ray emission. The spatial
analysis of this emission suggests that magnetic fields are amplified by one to
two orders of magnitude in strong shocks. Detection of several remnants in TeV
gamma rays implies a lower limit on the magnetic-field strength (or a
measurement, if the emission process is inverse-Compton upscattering of cosmic
microwave background photons). Upper limits to GeV emission similarly provide
lower limits on magnetic-field strengths. In the historical shell remnants,
lower limits on B range from 25 to 1000 microGauss. Two remnants show
variability of synchrotron X-ray emission with a timescale of years. If this
timescale is the electron-acceleration or radiative loss timescale, magnetic
fields of order 1 mG are also implied. In pulsar-wind nebulae, equipartition
arguments and dynamical modeling can be used to infer magnetic-field strengths
anywhere from about 5 microGauss to 1 mG. Polarized fractions are considerably
higher than in SNRs, ranging to 50 or 60% in some cases; magnetic-field
geometries often suggest a toroidal structure around the pulsar, but this is
not universal. Viewing-angle effects undoubtedly play a role. MHD models of
radio emission in shell SNRs show that different orientations of upstream
magnetic field, and different assumptions about electron acceleration, predict
different radio morphology. In the remnant of SN 1006, such comparisons imply a
magnetic-field orientation connecting the bright limbs, with a non-negligible
gradient of its strength across the remnant.Comment: 20 pages, 24 figures; to be published in SpSciRev. Minor wording
change in Abstrac
Rapid assessment of antibiotic susceptibility using a fully 3D-printed impedance- based biosensor
The sustained misuse and overuse of antibacterial agents is accelerating the emergence of antimicrobial resistance (AMR), which is becoming one of the major threats to public health. Abuse of antibiotics drives spontaneous evolution, bacterial mutation, and exchange of resistant genes through lateral gene transfer. Mitigating the worldwide impact of AMR requires enhanced antibiotic stewardship through faster diagnostic testing. In this work, we aim to tackle this issue via development of a fully 3D-printed electrochemical, gel-modified biosensor for rapid bacterial growth monitoring. By using electrochemical impedance spectroscopy, we have successfully identified growth profiles and confirmed antibiotic susceptibility of two ESKAPE pathogens, Escherichia coli and Pseudomonas aeruginosa, following overnight culture it was possible to determine antibiotic sensitivity in 90 min, altogether faster than the 24â48 h current gold standard of culture-based antimicrobial susceptibility testing with significant scope for optimisation. Results show a clear distinction between growth profiles in the presence and absence of amoxicillin, gentamicin, and fosfomycin, therefore demonstrating a rapid, cost-efficient platform for phenotypic antibiotic susceptibility testing within clinically relevant concentration ranges for conditions such as urinary tract infections and pneumonia
Current Results and Future Research Priorities in Late Effects after Hematopoietic Stem Cell Transplantation for Children with Sickle Cell Disease and Thalassemia: A Consensus Statement from the Second Pediatric Blood and Marrow Transplant Consortium International Conference on Late Effects after Pediatric Hematopoietic Stem Cell Transplantation
Transplantation and immunomodulatio
Reguladores vegetais no enraizamento e desenvolvimento de gemas de cana-de-açĂșcar tratadas termicamente
Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability
The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-PTSD) combined genome-wide case-control molecular genetic data across 11 multiethnic studies to quantify PTSD heritability, to examine potential shared genetic risk with schizophrenia, bipolar disorder, and major depressive disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we report a molecular genetics-based heritability estimate (h 2 SNP) for European-American females of 29% that is similar to h 2 SNP for schizophrenia and is substantially higher than h 2 SNP in European-American males (estimate not distinguishable from zero). We found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder. No single-nucleotide polymorphisms (SNPs) exceeded genome-wide significance in the transethnic (overall) meta-analysis and we do not replicate previously reported associations. Still, SNP-level summary statistics made available here afford the best-available molecular genetic index of PTSD - for both European- and African-American individuals - and can be used in polygenic risk prediction and genetic correlation studies of diverse phenotypes. Publication of summary statistics for 1/410 000 African Americans contributes to the broader goal of increased ancestral diversity in genomic data resources. In sum, the results demonstrate genetic influences on the development of PTSD, identify shared genetic risk between PTSD and other psychiatric disorders and highlight the importance of multiethnic/racial samples. As has been the case with schizophrenia and other complex genetic disorders, larger sample sizes are needed to identify specific risk loci
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