533 research outputs found
Optimization of a Polydimethylsiloxane Based Passive Sampler of Common Household Volatile Organic Compounds
Dangerous volatile organic compounds, or VOCs, can accumulate as indoor air pollution within homes causing health problems in the habitants. In order to determine the concentration of VOCs in such areas a field-deployable sampler is necessary. The focus of this work has been to develop an inexpensive, reusable, sensitive fielddeployable passive sampler for monitoring VOCs in indoor air. We have devised a sampler that uses polydimethylsiloxane (PDMS), which is a common inexpensive, nonpolar adsorbent. The sampler is comprised of an aluminum bottle coated with the PDMS. In operation, the coated portion is exposed to the air to be sampled. The bottle is then screwed into the top portion which keeps the material sealed-in. The sample from the aluminum bottle is then transferred to the GC for analysis using a Gas Phase Sampling Device (GSPID). In this work, sample equilibration time (in the bottle), GSPID gas flow rate and the sample loop filling timeswere optimized. Solutions containing toluene, ethylbenzene, and o-xylene were used as representatives for common household VOCs. Butanone was used as an internal standard in order to control reproducibility
Making the Most of Existing Resources: An Online Rubric Database in University-wide Writing Program Assessment
When creating an assessment plan to measure writing outcomes for a university-wide writing across the curriculum (WAC) program, administrators considered multi-layered evaluation methods for benchmarking and measuring internal growth of students. Although assessment plans must address these needs, the actual assessment practices must be flexible, accessible to faculty, and feasible--based on existing technological structures and data systems at an institution. The writing assessment that is provided addresses all of these elements and is offered as a model for other programs.
For this particular study, the internal aspect of the assessment plan that tracks growth of students over time is the centerpiece of the system. This online WAC rubric measures five distinct components of writing: Focus, Content, Organization, Style, and Language Conventions. Technical nuances of measuring longitudinal growth per individual student as well as the essential variables in data collection for future long-term meaningful analysis were considered when creating the online system. Data collected and analyzed through the system are shared. This online rubric, adaptable at other institutions, is offered as a method to balance the tension of large-scale accountability with course-specific writing assessment
Parent-of-origin effects in SOX2 anophthalmia syndrome
PURPOSE: Sex determining region Y (SRY)-box 2 (SOX2) anophthalmia syndrome is an autosomal dominant disorder manifesting as severe developmental eye malformations associated with brain, esophageal, genital, and kidney abnormalities. The syndrome is usually caused by de novo mutations or deletions in the transcription factor SOX2. To investigate any potential parental susceptibility factors, we set out to determine the parent of origin of the mutations or deletions, and following this, to determine if birth order or parental age were significant factors, as well as whether mutation susceptibility was related to any sequence variants in cis with the mutant allele. METHODS: We analyzed 23 cases of de novo disease to determine the parental origin of SOX2 mutations and deletions using informative single nucleotide polymorphisms and a molecular haplotyping approach. We examined parental ages for SOX2 mutation and deletion cases, compared these with the general population, and adjusted for birth order. RESULTS: Although the majority of subjects had mutations or deletions that arose in the paternal germline (5/7 mutation and 5/8 deletion cases), there was no significant paternal bias for new mutations (binomial test, p=0.16) or deletions (binomial test, p=0.22). For both mutation and deletion cases, there was no significant association between any single nucleotide polymorphism allele and the mutant chromosome (p>0.05). Parents of the subjects with mutations were on average older at the birth of the affected child than the general population by 3.8 years (p=0.05) for mothers and 3.3 years (p=0.66) for fathers. Parents of the subjects with deletions were on average younger than the general population by 3.0 years (p=0.17) for mothers and 2.1 years (p=0.19) for fathers. Combining these data, the difference in pattern of parental age between the subjects with deletions and mutations was evident, with a difference of 6.5 years for mothers (p=0.05) and 5.0 years for fathers (p=0.22), with the mothers and fathers of subjects with mutations being older than the mothers and fathers of subjects with deletions. We observed that 14 of the 23 (61%) affected children were the first-born child to their mother, with 10/15 of the mutation cases (66%) and 4/8 deletion cases (50%) being first born. This is in comparison to 35% of births with isolated congenital anomalies overall who are first born (p=0.008). CONCLUSIONS: Sporadic SOX2 mutations and deletions arose in both the male and female germlines. In keeping with several genetic disorders, we found that SOX2 mutations were associated with older parental age and the difference was statistically significant for mothers (p=0.05), whereas, although not statistically significant, SOX2 deletion cases had younger parents. With the current sample size, there was no evidence that sequence variants in cis surrounding SOX2 confer susceptibility to either mutations or deletions
DNA sequence to a million doses of COVID-19 therapeutic antibody in 9 months – Making the seemingly impossible, possible
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Negative selection of CD4+CD8+ thymocytes by T cell receptor-induced apoptosis requires a costimulatory signal that can be provided by CD28
Shift in recreational fishing catches as a function of an extreme cold event
There is an increasing recognition that the influence of extreme climate events (ECE) can be more significant in structuring ecosystem dynamics than the gradual effects of climate change. Still, our understanding of the effects of climate extremes on ecosystem services such as marine fisheries lags behind those of effects of gradual change. The significance of ECEs depends on the severity of the disturbance event and the resilience of a fish community. South Florida experienced an extreme cold spell in 2010 that provided the opportunity to study recreational fisheries resilience to ECEs. Our main goal was to examine how recreational fishing catch structures responded to the cold spell, and illustrate any spatial-specific recovery trajectory dynamics after extreme ecological responses. To address this, we implemented multivariate and nonlinear statistics on fishing guide reports for 20 recreational species. A significant shift in the catch structure occurred after the event, suggesting a high sensitivity of fish populations and fisheries in the region to ECEs. All fishing regions considered were affected, but the trajectory of the response and recovery varied across study areas. While some fish species experienced an expected decline (due to mortality), other species manifested an increase in catch. Of the main seven species considered in nonlinear models, three experienced a decline (bonefish, snook, goliath grouper), two experienced an increase (red drum, gray snapper), and the two had various weak trends (tarpon, spotted seatrout). Three years after the event, the catch structure has not returned to the original state, indicating a possible state shift, whose stability needs to be determined in future tracking of affected populations. Future work should also address the extent to which harvest may interfere with resilience to ECEs. Our work highlights the need to account for rare environmental forcing induced by ECEs to ensure the ecological and economical sustainability of key services such as recreational fisheries
Reduced plant water status under sub-ambient pCO2 limits plant productivity in the wild progenitors of C3 and C4 cereals.
BACKGROUND AND AIMS: The reduction of plant productivity by low atmospheric CO2 partial pressure (pCO2) during the last glacial period is proposed as a limiting factor for the establishment of agriculture. Supporting this hypothesis, previous work has shown that glacial pCO2 limits biomass in the wild progenitors of C3 and C4 founder crops, in part due to the direct effects of glacial pCO2 on photosynthesis. Here, we investigate the indirect role of pCO2 mediated via water status, hypothesizing that faster soil water depletion at glacial (18 Pa) compared to post-glacial (27 Pa) pCO2, due to greater stomatal conductance, feeds back to limit photosynthesis during drying cycles. METHODS: We grew four wild progenitors of C3 and C4 crops at glacial and post-glacial pCO2 and investigated physiological changes in gas exchange, canopy transpiration, soil water content and water potential between regular watering events. Growth parameters including leaf area were measured. KEY RESULTS: Initial transpiration rates were higher at glacial pCO2 due to greater stomatal conductance. However, stomatal conductance declined more rapidly over the soil drying cycle in glacial pCO2 and was associated with decreased intercellular pCO2 and lower photosynthesis. Soil water content was similar between pCO2 levels as larger leaf areas at post-glacial pCO2 offset the slower depletion of water. Instead the feedback could be linked to reduced plant water status. Particularly in the C4 plants, soil-leaf water potential gradients were greater at 18 Pa compared with 27 Pa pCO2, suggesting an increased ratio of leaf evaporative demand to supply. CONCLUSIONS: Reduced plant water status appeared to cause a negative feedback on stomatal aperture in plants at glacial pCO2, thereby reducing photosynthesis. The effects were stronger in C4 species, providing a mechanism for reduced biomass at 18 Pa. These results have added significance when set against the drier climate of the glacial period
Is the personal always political? Education and political knowledge strengthen the relationship between openness and conservatism
Abstract. Research demonstrates that the negative relationship between Openness to Experience and conservatism is heightened among the informed. We extend this literature using national survey data (Study 1; N = 13,203) and data from students (Study 2; N = 311). As predicted, education – a correlate of political sophistication – strengthened the negative relationship between Openness and conservatism (Study 1). Study 2 employed a knowledge-based measure of political sophistication to show that the Openness × Political Sophistication interaction was restricted to the Openness aspect of Openness. These studies demonstrate that knowledge helps people align their ideology with their personality, but that the Openness × Political Sophistication interaction is specific to one aspect of Openness – nuances that are overlooked in the literature. </jats:p
Sightings of Southern Resident killer whales in the Salish Sea 1976-2014
Southern Resident Killer Whales (SRKWs) or orcas, Orcinus orca, are resident year round in the Salish Sea, the inland waterways of Washington State and Southern British Columbia. The Whale Museum (TWM) has been collecting opportunistic sightings reports on SRKWs since 1976 with a goal of providing managers and regulatory agencies with reliable spatial data on SRKWs. Information in this database comes from five identified killer whale sighting sources and is systematically evaluated for accuracy before integration into the data set. To date, TWM sighting database has documented a total of 83,428 SRKW sightings in the Salish Sea. Sightings are concentrated in a few key hot spots with an overall pattern of consistent presence in the Central Salish Sea during the summer months and an increasing presence in Puget Sound Proper during the fall and early winter months. A notable shift in SRKW presence in Puget Sound in the late nineties was possibly driven by increased foraging on fall chum salmon after a group of L pod whales became trapped in Dyes Inlet in 1997. The Whale Museum’s dataset highlights the importance of long-term monitoring and shows how opportunistic datasets can be valuable tools for illuminating long-term spatial and temporal patterns
The 2011 Outburst of Recurrent Nova T Pyx: X-ray Observations Expose the White Dwarf Mass and Ejection Dynamics
The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and
became the subject of an intensive multi-wavelength observational campaign. We
analyze data from the Swift and Suzaku satellites to produce a detailed X-ray
light curve augmented by epochs of spectral information. X-ray observations
yield mostly non-detections in the first four months of outburst, but both a
super-soft and hard X-ray component rise rapidly after Day 115. The super-soft
X-ray component, attributable to the photosphere of the nuclear-burning white
dwarf, is relatively cool (~45 eV) and implies that the white dwarf in T Pyx is
significantly below the Chandrasekhar mass (~1 M_sun). The late turn-on time of
the super-soft component yields a large nova ejecta mass (>~10^-5 M_sun),
consistent with estimates at other wavelengths. The hard X-ray component is
well fit by a ~1 keV thermal plasma, and is attributed to shocks internal to
the 2011 nova ejecta. The presence of a strong oxygen line in this thermal
plasma on Day 194 requires a significantly super-solar abundance of oxygen and
implies that the ejecta are polluted by white dwarf material. The X-ray light
curve can be explained by a dual-phase ejection, with a significant delay
between the first and second ejection phases, and the second ejection finally
released two months after outburst. A delayed ejection is consistent with
optical and radio observations of T Pyx, but the physical mechanism producing
such a delay remains a mystery.Comment: Re-submitted to ApJ after revision
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