1,780 research outputs found
Standing Balance Stability and the Effects of Light Touch in Adults With Profound Loss of Vision-An Exploratory Study
Purpose: We evaluated the postural stability of adults with inherited profound vision loss and examined the effects of touch on their balance control. Methods: A total of 11 severely-sight impaired patients (mean [SD] age, 51.6 [5.3] years) and 11 control subjects (mean age, 49.7 [5.3] years) participated. Postural stability was measured using a force-balance platform eyes open/closed on a firm/foam surface under 3 test conditions: no touch, light touch, and unrestricted touch (UT), where "touch" involved placing their index finger on a rigid table. Average magnitude of center of foot pressure displacement was calculated. A somatosensory ratio (SR) was used to evaluate the somatosensory contribution to balance. A repeated measures ANOVA was used to investigate the effects of touch on standing balance. Results: Patients had a significantly increased SR compared to control subjects (mean [SD] SR controls = 1.2 [0.2], patients = 1.9 [0.5]; P < 0.01). There was a significant effect of touch, vision, and surface on balance control ("touch" F = 68.1, P < 0.01; "vision" F = 20.1, P < 0.01; "surface" F = 200.8, P < 0.01). Light touch attenuated sway in patients and controls. The effects were greater in controls when their vision was removed, and greater in patients when their somatosensory system was disrupted. Light touch was as effective as UT in attenuating sway. Conclusions: The results of this exploratory study suggest that patients with severe sight impairment show an increased somatosensory contribution to balance control compared to their normally sighted counterparts. Light touch significantly reduces sway amplitude in severely sight impaired adults when standing on the foam surface, that is, when the somatosensory system is perturbed
Modeling microevolution in a changing environment: The evolving quasispecies and the Diluted Champion Process
Several pathogens use evolvability as a survival strategy against acquired
immunity of the host. Despite their high variability in time, some of them
exhibit quite low variability within the population at any given time, a
somehow paradoxical behavior often called the evolving quasispecies. In this
paper we introduce a simplified model of an evolving viral population in which
the effects of the acquired immunity of the host are represented by the
decrease of the fitness of the corresponding viral strains, depending on the
frequency of the strain in the viral population. The model exhibits evolving
quasispecies behavior in a certain range of its parameters, ans suggests how
punctuated evolution can be induced by a simple feedback mechanism.Comment: 15 pages, 12 figures. Figures redrawn, some additional clarifications
in the text. To appear in Journal of Statistical Mechanics: Theory and
Experimen
Oakleaf: an S locus-linked mutation of Primula vulgaris that affects leaf and flower development
âąIn Primula vulgaris outcrossing is promoted through reciprocal herkogamy with insect-mediated cross-pollination between pin and thrum form flowers. Development of heteromorphic flowers is coordinated by genes at the S locus. To underpin construction of a genetic map facilitating isolation of these S locus genes, we have characterised Oakleaf, a novel S locus-linked mutant phenotype. âąWe combine phenotypic observation of flower and leaf development, with classical genetic analysis and next-generation sequencing to address the molecular basis of Oakleaf. âąOakleaf is a dominant mutation that affects both leaf and flower development; plants produce distinctive lobed leaves, with occasional ectopic meristems on the veins. This phenotype is reminiscent of overexpression of Class I KNOX-homeodomain transcription factors. We describe the structure and expression of all eight P. vulgaris PvKNOX genes in both wild-type and Oakleaf plants, and present comparative transcriptome analysis of leaves and flowers from Oakleaf and wild-type plants. âąOakleaf provides a new phenotypic marker for genetic analysis of the Primula S locus. We show that none of the Class I PvKNOX genes are strongly upregulated in Oakleaf leaves and flowers, and identify cohorts of 507 upregulated and 314 downregulated genes in the Oakleaf mutant
Integration of genetic and physical maps of the Primula vulgaris S locus and localization by chromosome in situ hybridization
âąHeteromorphic flower development in Primula is controlled by the S locus. The S locus genes, which control anther position, pistil length and pollen size in pin and thrum flowers, have not yet been characterized. We have integrated S-linked genes, marker sequences and mutant phenotypes to create a map of the P. vulgaris S locus region that will facilitate the identification of key S locus genes. We have generated, sequenced and annotated BAC sequences spanning the S locus, and identified its chromosomal location. âąWe have employed a combination of classical genetics and three-point crosses with molecular genetic analysis of recombinants to generate the map. We have characterized this region by Illumina sequencing and bioinformatic analysis, together with chromosome in situ hybridization. âąWe present an integrated genetic and physical map across the P. vulgaris S locus flanked by phenotypic and DNA sequence markers. BAC contigs encompass a 1.5-Mb genomic region with 1 Mb of sequence containing 82 S-linked genes anchored to overlapping BACs. The S locus is located close to the centromere of the largest metacentric chromosome pair. âąThese data will facilitate the identification of the genes that orchestrate heterostyly in Primula and enable evolutionary analyses of the S locus
Factors Affecting a Recently Purchased Handgunâs Risk for Use in Crime under Circumstances That Suggest Gun Trafficking
While many handguns are used in crime each year in the USA, most are not. We conducted this study to identify factors present at the time of a handgunâs most recent retail sale that were associated with its subsequent use in crime under circumstances suggesting that the handgun had been traffickedâpurchased with the intent of diverting it to criminal use. Handguns acquired in multiple-gun purchases were of particular interest. Using data for 180,321 handguns purchased from federally licensed retailers in California in 1996, we studied attributes of the handguns, the retailers selling them, the purchasers, and the sales transactions. Our outcome measure was a handgunâs recovery by a police agency, followed by a gun ownership trace, conducted by the Bureau of Alcohol, Tobacco, Firearms and Explosives, that determined (a) that the recovery had occurred within 3Â years of the handgunâs most recent purchase from a licensed retailer and (b) that the person who possessed the gun when it was recovered by police was not its most recent purchaser. Altogether, 722 handguns were recovered and had trace results that met the additional criteria. Handguns acquired in multiple-gun, same-day transactions were more likely to be traced than were single-purchase handguns (odds ratio [OR] 1.33, 95% confidence intervals [CI] 1.08 to 1.63). This was not the case for multiple-purchase handguns defined more broadly as multiple handguns purchased by one individual over any 30-day period as used in âone-gun-a-monthâ laws. Bivariate regressions indicated increased risk of a handgun being traced when it sold new for $150 or less (OR 4.28, 95% CI 3.59 to 5.11) or had been purchased by a woman (OR 2.02, 95% CI 1.62 to 2.52). Handguns sold by retailers who also had a relatively high proportion (â„2%) of purchases denied because the prospective purchasers were prohibited from owning firearms were more likely to be traced than were those sold by other retailers (OR 4.09, 95% CI 3.39 to 4.94). These findings persisted in multivariate analyses. Our findings suggest specific strategies for intervention to prevent gun violence
Effects of Policies Designed to Keep Firearms from High-Risk Individuals
This article summarizes and critiques available evidence from studies published between 1999 and August 2014 on the effects of policies designed to keep firearms from high-risk individuals in the United States. Some prohibitions for high-risk individuals (e.g., those under domestic violence restraining orders, violent misdemeanants) and procedures for checking for more types of prohibiting conditions are associated with lower rates of violence. Certain laws intended to prevent prohibited persons from accessing firearms -- rigorous permit-to-purchase, comprehensive background checks, strong regulation and oversight of gun dealers, and requiring gun owners to promptly report lost or stolen firearms -- are negatively associated with the diversion of guns to criminals. Future research is needed to examine whether these laws curtail nonlethal gun violence and whether the effects of expanding prohibiting conditions for firearm possession are modified by the presence of policies to prevent diversion
EPR detection and characterisation of a paramagnetic Mo(III) dihydride intermediate involved in electrocatalytic hydrogen evolution
EPR spectroscopy and theoretical data show that the slow heterogeneous electron-transfer kinetics associated with the reduction of an 18-electron Mo(IV) acetato dihydride are a consequence of an η2âη1 rearrangement of the carboxylate ligand which gives a unique paramagnetic 17-electron Mo(III) dihydride
Recommended from our members
Salmonella flagellin activates NAIP/NLRC4 and canonical NLRP3 inflammasomes in human macrophages
Infection of human macrophages with Salmonella enterica serovar Typhimurium (S. Typhimurium) leads to inflammasome activation. Inflammasomes are multi-protein complexes facilitating caspaseâ1 activation and subsequent gasdermin D-mediated cell death and interleukinâ1ÎČ and interleukinâ18 cytokine release. The NAIP/NLRC4 inflammasome is activated by multiple bacterial protein ligands including flagellin from the flagellum and the needle protein PrgI from the S. Typhimurium type III secretion system. Here we show that transfected ultrapure flagellin from S. Typhimurium induced cell death and cytokine secretion in THPâ1 cells and primary human monocyte-derived macrophages (hMDM). In THPâ1 cells, NAIP/NLRC4 and NLRP3 played redundant roles in inflammasome activation during infection with S. Typhimurium. Knock-out of NAIP or NLRC4 in THPâ1 cells revealed that flagellin, but not PrgI, now activated the NLRP3 inflammasome through a ROS- and/or cathepsin-dependent mechanism that was independent of caspaseâ4/5 activity. In conclusion, our data suggest that NLRP3 can be activated by flagellin to act as a âsafety netâ to maintain inflammasome activation under conditions of suboptimal NAIP/NLRC4 activation, as observed in THPâ1 cells, possibly explaining the redundant role of NLRP3 and NAIP/NLRC4 during S. Typhimurium infection.Wellcome Trus
Recruited macrophages that colonize the post-inflammatory peritoneal niche convert into functionally divergent resident cells
Inflammation generally leads to recruitment of monocyte-derived macrophages. What regulates the fate of these cells and to what extent they can assume the identity and function of resident macrophages is unclear. Here, we show that macrophages elicited into the peritoneal cavity during mild inflammation persist long-term but are retained in an immature transitory state of differentiation due to the presence of enduring resident macrophages. By contrast, severe inflammation results in ablation of resident macrophages and a protracted phase wherein the cavity is incapable of sustaining a resident phenotype, yet ultimately elicited cells acquire a mature resident identity. These macrophages also have transcriptionally and functionally divergent features that result from inflammation-driven alterations to the peritoneal cavity micro-environment and, to a lesser extent, effects of origin and time-of-residency. Hence, rather than being predetermined, the fate of inflammation-elicited peritoneal macrophages seems to be regulated by the environment
Constraints on CDM cosmology from galaxy power spectrum, CMB and SNIa evolution
We examine the constraints that can be obtained on standard cold dark matter
models from the most currently used data set: CMB anisotropies, type Ia
supernovae and the SDSS luminous red galaxies. We also examine how these
constraints are widened when the equation of state parameter and the
curvature parameter are left as free parameters. For the
CDM model, our 'vanilla' model, cosmological parameters are tightly
constrained and consistent with current estimates from various methods. When
the dark energy parameter is free we find that the constraints remain
mostly unchanged, i.e. changes are smaller than the 1 sigma uncertainties.
Similarly, relaxing the assumption of a flat universe leads to nearly identical
constraints on the dark energy density parameter of the universe
, baryon density of the universe , the optical
depth , the index of the power spectrum of primordial fluctuations ,
with most one sigma uncertainties better than 5%. More significant changes
appear on other parameters: while preferred values are almost unchanged,
uncertainties for the physical dark matter density , Hubble
constant and are typically twice as large. We found that
different methodological approaches on large scale structure estimates lead to
appreciable differences in preferred values and uncertainty widths. We also
found that possible evolution in SNIa intrinsic luminosity does not alter these
constraints by much, except for , for which the uncertainty is twice as
large. At the same time, this possible evolution is severely constrained. We
conclude that systematic uncertainties for some estimated quantities are
similar or larger than statistical ones.Comment: Revised version, 9 pages, 8 figures, accepted for publication in A&
- âŠ