321 research outputs found
Using Fundamental Measure Theory to Treat the Correlation Function of the Inhomogeneous Hard-Sphere Fluid
We investigate the value of the correlation function of an inhomogeneous
hard-sphere fluid at contact. This quantity plays a critical role in
Statistical Associating Fluid Theory (SAFT), which is the basis of a number of
recently developed classical density functionals. We define two averaged values
for the correlation function at contact, and derive formulas for each of them
from the White Bear version of the Fundamental Measure Theory functional, using
an assumption of thermodynamic consistency. We test these formulas, as well as
two existing formulas against Monte Carlo simulations, and find excellent
agreement between the Monte Carlo data and one of our averaged correlation
functions
Privacy, anonymity, visibility: dilemmas in tech use by marginalised communities
Making All Voices Count Research ReportThis paper synthesises reflections and learnings from two studies, in Kenya and South Africa, about how marginalised communities – lesbian, gay, bisexual, trans and queer (LGBTQ) people in Nairobi, Kenya, and economically marginalised housing and urban development rights activists in Johannesburg, South Africa – use technologies commonly applied in transparency and accountability work, and the limits of their use of these technologies.Omidyar NetworkSIDADFIDUSAI
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Theoretical Prediction of Disrupted Min Oscillation in Flattened Escherichia coli
The dynamics of the Min-protein system help Escherichia coli regulate the process of cell division by identifying the center of the cell. While this system exhibits robust bipolar oscillations in wild-type cell shapes, recent experiments have shown that when the cells are mechanically deformed into wide, flattened out, irregular shapes, the spatial regularity of these oscillations breaks down. We employ widely used stochastic and deterministic models of the Min system to simulate cells with flattened shapes. The deterministic model predicts strong bipolar oscillations, in contradiction with the experimentally observed behavior, while the stochastic model, which is based on the same reaction-diffusion equations, predicts more spatially irregular oscillations. We further report simulations of flattened but more symmetric shapes, which suggest that the flattening and lateral expansion may contribute as much to the irregular oscillation behavior as the asymmetry of the cell shapes
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Improved association in a classical density functional theory for water
We present a modification to our recently published statistical associating fluid theory-based classical
density functional theory for water. We have recently developed and tested a functional for the
averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate
at interfaces than earlier approximations. We now incorporate this improved functional into the
association term of our free energy functional for water, improving its description of hydrogen bonding.
We examine the effect of this improvement by studying two hard solutes (a hard hydrophobic
rod and a hard sphere) and a Lennard-Jones approximation of a krypton atom solute. The improved
functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen
bonds broken in the vicinity of the hard solutes. We find an improvement of the partial radial
distribution for a krypton atom in water when compared with experiment
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Using fundamental measure theory to treat the correlation function of the inhomogeneous hard-sphere fluid
We investigate the value of the correlation function of an inhomogeneous hard-sphere fluid at contact. This quantity plays a critical role in statistical associating fluid theory, which is the basis of a number of recently developed classical density functionals. We define two averaged values for the correlation function at contact and derive formulas for each of them from the White Bear version of the fundamental measure theory functional, using an assumption of thermodynamic consistency. We test these formulas, as well as two existing formulas, against Monte Carlo simulations and find excellent agreement between the Monte Carlo data and one of our averaged correlation functions
Open video data sharing in developmental and behavioural science
Video recording is a widely used method for documenting infant and child
behaviours in research and clinical practice. Video data has rarely been shared
due to ethical concerns of confidentiality, although the need of shared
large-scaled datasets remains increasing. This demand is even more imperative
when data-driven computer-based approaches are involved, such as screening
tools to complement clinical assessments. To share data while abiding by
privacy protection rules, a critical question arises whether efforts at data
de-identification reduce data utility? We addressed this question by showcasing
the Prechtl's general movements assessment (GMA), an established and globally
practised video-based diagnostic tool in early infancy for detecting
neurological deficits, such as cerebral palsy. To date, no shared
expert-annotated large data repositories for infant movement analyses exist.
Such datasets would massively benefit training and recalibration of human
assessors and the development of computer-based approaches. In the current
study, sequences from a prospective longitudinal infant cohort with a total of
19451 available general movements video snippets were randomly selected for
human clinical reasoning and computer-based analysis. We demonstrated for the
first time that pseudonymisation by face-blurring video recordings is a viable
approach. The video redaction did not affect classification accuracy for either
human assessors or computer vision methods, suggesting an adequate and
easy-to-apply solution for sharing movement video data. We call for further
explorations into efficient and privacy rule-conforming approaches for
deidentifying video data in scientific and clinical fields beyond movement
assessments. These approaches shall enable sharing and merging stand-alone
video datasets into large data pools to advance science and public health
Photon-Photon and Electron-Photon Colliders with Energies Below a TeV
We investigate the potential for detecting and studying Higgs bosons in and collisions at future linear colliders with energies below a TeV. Our study incorporates realistic spectra based on available laser technology, and NLC and CLIC acceleration techniques. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson based on a devoted low energy machine with GeV; b) the heavy MSSM Higgs bosons; and c) charged Higgs bosons in collisions.We investigate the potential for detecting and studying Higgs bosons in and collisions at future linear colliders with energies below a TeV. Our study incorporates realistic spectra based on available laser technology, and NLC and CLIC acceleration techniques. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson based on a devoted low energy machine with GeV; b) the heavy MSSM Higgs bosons; and c) charged Higgs bosons in collisions
Environmentally enriched male mink gain more copulations than stereotypic, barren-reared competitors
Wild carnivores in zoos, conservation breeding centres, and farms commonly live in relatively small, unstimulating enclosures. Under these captive conditions, in a range of species including giant pandas, black-footed ferrets, and European mink, male reproductive abilities are often poor. Such problems have long been hypothesized to be caused by these animals' housing conditions. We show for the first time that rearing under welfare-improving (i.e., highly valued and stress-reducing) environmental enrichments enhances male carnivores' copulatory performance: in mate choice competitions, enriched male American mink (Neovison vison) mated more often than non-enriched males. We screened for several potential mediators of this effect. First was physiological stress and its impact on reproductive physiology; second, stress-mediated changes in morphology and variables related to immunocompetence that could influence male attractiveness; and third, behavioural changes likely to affect social competence, particularly autistic-like excessive routine and repetition ('perseveration') as is reflected in the stereotypies common in captive animals. Consistent with physiological stress, excreted steroid metabolites revealed that non-enriched males had higher cortisol levels and lower androgen levels than enriched conspecifics. Their os penises (bacula) also tended to be less developed. Consistent with reduced attractiveness, non-enriched males were lighter, with comparatively small spleens and a trend to greater fluctuating asymmetry. Consistent with impaired social competence, non-enriched males performed more stereotypic behaviour (e. g., pacing) in their home cages. Of all these effects, the only significant predictor of copulation number was stereotypy (a trend suggesting that low bodyweights may also be influential): highly stereotypic males gained the fewest copulations. The neurophysiological changes underlying stereotypy thus handicap males sexually. We hypothesise that such males are abnormally perseverative when interacting with females. Investigating similar problems in other taxa would be worthwhile, since many vertebrates, wild and domestic, live in conditions that cause stereotypic behaviour and/or impair neurological development
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