3,350 research outputs found
Hyperacute motion detection by the lateral eyes of jumping spider
Jumping spiders (Salticidae) are renowned for their high performing visual system. In addition to their prominent forward-facing telescope-like principal eyes, salticids possess two or three pairs of secondary eyes used for wide-angle motion detection. Salticids orient towards relevant sources of motion detected by the secondary eyes, enabling them to inspect the stimulus with their spatially acute principal eyes. The anteriormost pair of secondary eyes, the anterior lateral (AL) eyes, also faces forward and has higher spatial acuity than the other, laterally-facing, secondary eyes. We used small computer-generated targets to elicit orienting saccades from tethered jumping spiders in order to examine the perceptual limits of the AL eyes. We describe the contrast thresholds of male and female spiders, investigate the reaction time between stimulus appearance and initiation of orientation, as well as the minimum distance a stimulus must travel before eliciting a saccade. Our results show that female spiders react to lower contrast stimuli than males and demonstrate that the secondary eyes can detect stimulus displacements considerably smaller than the inter-receptor angle. © 2012 Elsevier Ltd
Tests of the Gravitational Inverse-Square Law
We review recent experimental tests of the gravitational inverse-square law
and the wide variety of theoretical considerations that suggest the law may
break down in experimentally accessible regions.Comment: 81 pages, 10 figures, submitted by permission of the Annual Review of
Nuclear and Particle Science. Final version of this material is scheduled to
appear in the Annual Review of Nuclear and Particle Science Vol. 53, to be
published in December 2003 by Annual Reviews, http://AnnualReviews.or
Christ Stilling the Tempest
Fear was in the tossing bark
When stormy winds grew loud
And waves came rolling high and dark,
And the tall mast was bow\u27d
And men stood breathless in their dread
And baffeled in their skill
But ONE was there, who rose and said
To the wild sea Be still!
To the wild sea Be still!
And the wind ceased it ceased that word
Pass\u27d the gloomy sky
The troubled billows knew their Lord
And sank beneath his eye.
And Slumber settled on the deep,
And silence on the blast
As when the righteous fall asleep,
When death\u27s fierce throes are past
When death\u27s fierce throes are past
Thou that didst rule the angry hour,
And tame the tempests mood
Oh! send they Spirit forth in pow\u27r
O\u27er our dark souls to brood!
Thou that didst bow the billows pride
Thy mandates to fulfil
So speak to passion\u27s raging tide
Speak and say Peace, be still
Peace, be stil
NUTRItion and CLIMate (NUTRICLIM): investigating the relationship between climate variables and childhood malnutrition through agriculture, an exploratory study in Burkina Faso
Malnutrition remains a leading cause of death in children in low- and middle-income countries; this will be aggravated by climate change. Annually, 6.9 million deaths of children under 5 were attributable directly or indirectly to malnutrition. Although these figures have recently decreased, evidence shows that a world with a medium climate (local warming up to 3–4 °C) will create an additional 25.2 million malnourished children. This proof of concept study explores the relationships between childhood malnutrition (more specifically stunting), regional agricultural yields, and climate variable through the use of remote sensing (RS) satellite imaging along with algorithms to predict the effect of climate variability on agricultural yields and on malnutrition of children under 5. The success of this proof of purpose study, NUTRItion and CLIMate (NUTRICLIM), should encourage researchers to apply both concept and tools to study of the link between weather variability, crop yield, and malnutrition on a larger scale. It would also allow for linking such micro-level data to climate models and address the challenge of projecting the additional impact of childhood malnutrition from climate change to various policy relevant time horizons
Flavor in Minimal Conformal Technicolor
We construct a complete, realistic, and natural UV completion of minimal
conformal technicolor that explains the origin of quark and lepton masses and
mixing angles. As in "bosonic technicolor", we embed conformal technicolor in a
supersymmetric theory, with supersymmetry broken at a high scale. The exchange
of heavy scalar doublets generates higher-dimension interactions between
technifermions and quarks and leptons that give rise to quark and lepton masses
at the TeV scale. Obtaining a sufficiently large top quark mass requires strong
dynamics at the supersymmetry breaking scale in both the top and technicolor
sectors. This is natural if the theory above the supersymmetry breaking also
has strong conformal dynamics. We present two models in which the strong top
dynamics is realized in different ways. In both models, constraints from
flavor-changing effects can be easily satisfied. The effective theory below the
supersymmetry breaking scale is minimal conformal technicolor with an
additional light technicolor gaugino. We argue that this light gaugino is a
general consequence of conformal technicolor embedded into a supersymmetric
theory. If the gaugino has mass below the TeV scale it will give rise to an
additional pseudo Nambu-Goldstone boson that is observable at the LHC.Comment: 37 pages; references adde
A Catalog of Reference Genomes from the Human Microbiome
The human microbiome refers to the community of microorganisms including prokaryotes, viruses
and microbial eukaryotes that populate the human body. The National Institutes of Health launched
an initiative that focuses describing the diversity of microbial species associated with health and
disease. The first phase of this initiative includes the sequencing of hundreds of microbial reference
genomes, coupled to metagenomic sequencing from multiple body sites. Here we present results
from an initial reference genome sequencing of 178 microbial genomes. From 547,968 predicted
polypeptides that correspond to the gene complement of these strains “novel” polypeptides that had
both unmasked sequence length > 100 amino acids and no BLASTP match to any non-reference
entry in the nr subset were defined. This analysis resulted in a set of 30,867 polypeptides, of which
29,987 (~97%) were unique. In addition, this set of microbial genomes allows for ~ 40% of random
sequences from the microbiome of the gastrointestinal tract to be associated with organisms based
on the match criteria used. Insights into pan-genome analysis suggest that we are still far from
saturating microbial species genetic datasets. In addition, the associated metrics and standards used
by the group for quality assurance are presented
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Impacts of elevated atmospheric CO₂ on nutrient content of important food crops.
One of the many ways that climate change may affect human health is by altering the nutrient content of food crops. However, previous attempts to study the effects of increased atmospheric CO2 on crop nutrition have been limited by small sample sizes and/or artificial growing conditions. Here we present data from a meta-analysis of the nutritional contents of the edible portions of 41 cultivars of six major crop species grown using free-air CO2 enrichment (FACE) technology to expose crops to ambient and elevated CO2 concentrations in otherwise normal field cultivation conditions. This data, collected across three continents, represents over ten times more data on the nutrient content of crops grown in FACE experiments than was previously available. We expect it to be deeply useful to future studies, such as efforts to understand the impacts of elevated atmospheric CO2 on crop macro- and micronutrient concentrations, or attempts to alleviate harmful effects of these changes for the billions of people who depend on these crops for essential nutrients
FCNC Effects in a Minimal Theory of Fermion Masses
As a minimal theory of fermion masses we extend the SM by heavy vectorlike
fermions, with flavor-anarchical Yukawa couplings, that mix with chiral
fermions such that small SM Yukawa couplings arise from small mixing angles.
This model can be regarded as an effective description of the fermionic sector
of a large class of existing flavor models and thus might serve as a useful
reference frame for a further understanding of flavor hierarchies in the SM.
Already such a minimal framework gives rise to FCNC effects through exchange of
massive SM bosons whose couplings to the light fermions get modified by the
mixing. We derive general formulae for these corrections and discuss the bounds
on the heavy fermion masses. Particularly stringent bounds, in a few TeV range,
come from the corrections to the Z couplings.Comment: 19 pages, 1 figur
Efficacy and safety of enzyme replacement therapy with BMN 110 (elosulfase alfa) for Morquio A syndrome (mucopolysaccharidosis IVA): a phase 3 randomised placebo-controlled study.
ObjectiveTo assess the efficacy and safety of enzyme replacement therapy (ERT) with BMN 110 (elosulfase alfa) in patients with Morquio A syndrome (mucopolysaccharidosis IVA).MethodsPatients with Morquio A aged ≥5 years (N = 176) were randomised (1:1:1) to receive elosulfase alfa 2.0 mg/kg/every other week (qow), elosulfase alfa 2.0 mg/kg/week (weekly) or placebo for 24 weeks in this phase 3, double-blind, randomised study. The primary efficacy measure was 6-min walk test (6MWT) distance. Secondary efficacy measures were 3-min stair climb test (3MSCT) followed by change in urine keratan sulfate (KS). Various exploratory measures included respiratory function tests. Patient safety was also evaluated.ResultsAt week 24, the estimated mean effect on the 6MWT versus placebo was 22.5 m (95 % CI 4.0, 40.9; P = 0.017) for weekly and 0.5 m (95 % CI -17.8, 18.9; P = 0.954) for qow. The estimated mean effect on 3MSCT was 1.1 stairs/min (95 % CI -2.1, 4.4; P = 0.494) for weekly and -0.5 stairs/min (95 % CI -3.7, 2.8; P = 0.778) for qow. Normalised urine KS was reduced at 24 weeks in both regimens. In the weekly dose group, 22.4 % of patients had adverse events leading to an infusion interruption/discontinuation requiring medical intervention (only 1.3 % of all infusions in this group) over 6 months. No adverse events led to permanent treatment discontinuation.ConclusionsElosulfase alfa improved endurance as measured by the 6MWT in the weekly but not qow dose group, did not improve endurance on the 3MSCT, reduced urine KS, and had an acceptable safety profile
Murine model for Fusarium oxysporum invasive fusariosis reveals organ-specific structures for dissemination and long-term persistence
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