785 research outputs found
Human and bovine viruses in the Milwaukee River watershed: Hydrologically relevant representation and relations with environmental variables
AbstractTo examine the occurrence, hydrologic variability, and seasonal variability of human and bovine viruses in surface water, three stream locations were monitored in the Milwaukee River watershed in Wisconsin, USA, from February 2007 through June 2008. Monitoring sites included an urban subwatershed, a rural subwatershed, and the Milwaukee River at the mouth. To collect samples that characterize variability throughout changing hydrologic periods, a process control system was developed for unattended, large-volume (56–2800L) filtration over extended durations. This system provided flow-weighted mean concentrations during runoff and extended (24-h) low-flow periods. Human viruses and bovine viruses were detected by real-time qPCR in 49% and 41% of samples (n=63), respectively. All human viruses analyzed were detected at least once including adenovirus (40% of samples), GI norovirus (10%), enterovirus (8%), rotavirus (6%), GII norovirus (1.6%) and hepatitis A virus (1.6%). Three of seven bovine viruses analyzed were detected including bovine polyomavirus (32%), bovine rotavirus (19%), and bovine viral diarrhea virus type 1 (5%). Human viruses were present in 63% of runoff samples resulting from precipitation and snowmelt, and 20% of low-flow samples. Maximum human virus concentrations exceeded 300genomiccopies/L. Bovine viruses were present in 46% of runoff samples resulting from precipitation and snowmelt and 14% of low-flow samples. The maximum bovine virus concentration was 11genomiccopies/L. Statistical modeling indicated that stream flow, precipitation, and season explained the variability of human viruses in the watershed, and hydrologic condition (runoff event or low-flow) and season explained the variability of the sum of human and bovine viruses; however, no model was identified that could explain the variability of bovine viruses alone. Understanding the factors that affect virus fate and transport in rivers will aid watershed management for minimizing human exposure and disease transmission
Correlated double-electron additions at the edge of a two-dimensional electronic system
We create laterally large and low disorder quantum well based quantum dots to
study single electron additions to two dimensional electron systems (2DES).
Electrons tunnel into these dots across an AlGaAs tunnel barrier from a single
electrode. Using single-electron capacitance spectroscopy in a dilution
refrigerator, we identify capacitance peaks for the addition of the first
electron to a dot and record subsequent peaks in the addition spectrum up to
occupancies of thousands of electrons. Here, we report two remarkable phenomena
that occur in the filling factor range to while selectively
probing electron additions to the edge states of the dot: (1) Coulomb blockade
peaks arise from the entrance of two electrons rather than one; (2) at and near
filling factor 5/2 and at fixed gate voltage, these double-height peaks appear
uniformly with a periodicity of . At other filling factors in the range
to , the mean periodicity for the twice-height electron peaks
remains , but the twice-height peaks are instead further bunched into
pairs of double-height peaks, with pairs spaced apart. The unusual
two-electron Coulomb blockade peaks suggest a novel pair tunneling effect that
involves electron correlations that arise in the quantum dot, with spectra at
identical to those previously only seen in superconducting dots.Comment: Added discussion to "bunching phenomena" section in supplemen
Bostonia. Volume 11
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Bostonia. Volume 4
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Tohoku-Hiroshima-Nagoya planetary spectra library: A method for characterizing planets in the visible to near infrared
There has not been a comprehensive framework for comparing spectral data from
different planets.Such a framework is needed for the study of extrasolar
planets and objects within the solar system. We have undertaken observations to
compile a library of planet spectra for all planets, some moons, and some dwarf
planets in the solar system to study their general spectroscopic and
photometric natures. During May and November of 2008, we acquired spectra for
the planets using TRISPEC, which is capable of simultaneous three-band
spectroscopy in a wide wavelength range of 0.45 - 2.5 microns with low
resolving power (lambda-over-Delta-lambda is 140 - 360). Patterns emerge from
comparing the spectra. Analyzing their general spectroscopic and photometric
natures, we show that it is possible to distinguish between gas planets, soil
planets and ice planets. These methods can be applied to extrasolar
observations using low resolution spectrography or broad-band filters. The
present planet spectral library is the first library to contain observational
spectra for all of the solar system planets, based on simultaneous observations
in visible and near infrared wavelengths. This library will be a useful
reference for analyzing extrasolar planet spectra, and for calibrating
planetary data sets.Comment: 11 pages, 6 figures, Accepted on 28/08/2009 to appear in Section 10.
Planets and planetary systems of Astronomy and Astrophysic
Natural selection. II. Developmental variability and evolutionary rate
In classical evolutionary theory, genetic variation provides the source of
heritable phenotypic variation on which natural selection acts. Against this
classical view, several theories have emphasized that developmental variability
and learning enhance nonheritable phenotypic variation, which in turn can
accelerate evolutionary response. In this paper, I show how developmental
variability alters evolutionary dynamics by smoothing the landscape that
relates genotype to fitness. In a fitness landscape with multiple peaks and
valleys, developmental variability can smooth the landscape to provide a
directly increasing path of fitness to the highest peak. Developmental
variability also allows initial survival of a genotype in response to novel or
extreme environmental challenge, providing an opportunity for subsequent
adaptation. This initial survival advantage arises from the way in which
developmental variability smooths and broadens the fitness landscape.
Ultimately, the synergism between developmental processes and genetic variation
sets evolutionary rate
Moving word learning to a novel space: A dynamic systems view of referent selection and retention
Theories of cognitive development must address both the issue of how children bring their knowledge to bear on behavior in-the-moment, and how knowledge changes over time. We argue that seeking answers to these questions requires an appreciation of the dynamic nature of the developing system in its full, reciprocal complexity. We illustrate this dynamic complexity with results from two lines of research on early word learning. The first demonstrates how the child’s active engagement with objects and people supports referent selection via memories for what objects were previously seen in a cued location. The second set of results highlights changes in the role of novelty and attentional processes in referent selection and retention as children’s knowledge of words and objects grows. Together this work suggests understanding systems for perception, action, attention, and memory and their complex interaction is critical to understand word learning. We review recent literature that highlights the complex interactions between these processes in cognitive development and point to critical issues for future work
Boron-Based Inhibitors of the NLRP3 Inflammasome.
NLRP3 is a receptor important for host responses to infection, yet is also known to contribute to devastating diseases such as Alzheimer's disease, diabetes, atherosclerosis, and others, making inhibitors for NLRP3 sought after. One of the inhibitors currently in use is 2-aminoethoxy diphenylborinate (2APB). Unfortunately, in addition to inhibiting NLRP3, 2APB also displays non-selective effects on cellular Ca2+ homeostasis. Here, we use 2APB as a chemical scaffold to build a series of inhibitors, the NBC series, which inhibit the NLRP3 inflammasome in vitro and in vivo without affecting Ca2+ homeostasis. The core chemical insight of this work is that the oxazaborine ring is a critical feature of the NBC series, and the main biological insight the use of NBC inhibitors led to was that NLRP3 inflammasome activation was independent of Ca2+. The NBC compounds represent useful tools to dissect NLRP3 function, and may lead to oxazaborine ring-containing therapeutics
Prevalence of childhood disability and the characteristics and circumstances of disabled children in the UK : secondary analysis of the Family Resources Survey
Background: Robust data on the prevalence of childhood disability and the circumstances and characteristics of
disabled children is crucial to understanding the relationship between impairment and social disadvantage. It is also
crucial for public policy development aimed at reducing the prevalence of childhood disability and providing
appropriate and timely service provision. This paper reports prevalence rates for childhood disability in the United
Kingdom (UK) and describes the social and household circumstances of disabled children, comparing these where
appropriate to those of non-disabled children.
Methods: Data were generated from secondary analysis of the Family Resources Survey, a national UK cross-sectional
survey, (2004/5) which had data on 16,012 children aged 0-18 years. Children were defined as disabled if they met the
Disability Discrimination Act (DDA) definition (1995 and 2005). Frequency distributions and cross-tabulations were run
to establish prevalence estimates, and describe the circumstances of disabled children. To establish the association
between individual social and material factors and childhood disability when other factors were controlled for, logistic
regression models were fitted on the dependent variable 'DDA defined disability'.
Results: 7.3% (CI 6.9, 7.7) of UK children were reported by as disabled according to the DDA definition. Patterns of
disability differed between sexes with boys having a higher rate overall and more likely than girls to experience
difficulties with physical coordination; memory, concentration and learning; communication. Disabled children lived in
different personal situations from their non-disabled counterparts, and were more likely to live with low-income,
deprivation, debt and poor housing. This was particularly the case for disabled children from black/minority ethnic/
mixed parentage groups and lone-parent households. Childhood disability was associated with lone parenthood and
parental disability and these associations persisted when social disadvantage was controlled for.
Conclusion: These analyses suggest that UK disabled children experience higher levels of poverty and personal and
social disadvantage than other children. Further research is required to establish accurate prevalence estimates of
childhood disability among different black and minority ethnic groups and to understand the associations between
childhood disability and lone parenthood and the higher rates of sibling and parental disability in households with
disabled children
Accumulation of anthocyanins in tomato skin extends shelf life
Shelf life is one of the most important traits for the tomato (Solanum lycopersicum) industry. Two key factors, post-harvest over-ripening and susceptibility to post-harvest pathogen infection, determine tomato shelf life.
Anthocyanins accumulate in the skin of Aft/Aft atv/atv tomatoes, the result of introgressing alleles affecting anthocyanin biosynthesis in fruit from two wild relatives of tomato, which results in extended fruit shelf life. Compared with ordinary, anthocyanin-less tomatoes, the fruits of Aft/Aft atv/atv keep longer during storage and are less susceptible to Botrytis cinerea, a major tomato pathogen, post-harvest.
Using genetically modified tomatoes over-producing anthocyanins, we confirmed that skin-specific accumulation of anthocyanins in tomato is sufficient to reduce the susceptibility of fruit to Botrytis cinerea.
Our data indicate that accumulation of anthocyanins in tomato fruit, achieved either by traditional breeding or genetic engineering can be an effective way to extend tomato shelf life
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