465 research outputs found
The Geology, Geochemistry and Ecology of a Shallow Water Submarine Hydrothermal Vent Bahía Concepción, Baja California Sur, México
I studied a shallow water (O-13m water depths) hydrothermal vent in Bahía Concepción, Baja California Sur, México. Investigations using side-scan sonar and SCUBA suggested that the submarine hydrothermal activity is mainly controlled by a NW-SE trending onshore-offshore fault. Compared to seawater, vent fluids are enriched in Ca, Mn, HC03, SiO2, B, As, Li, Fe, Rb, and Sr, and depleted in Na, Cl, Mg, and S04, with calculated end-member temperatures up to 220°C. The vent gas is primarily nitrogen, carbon dioxide, and methane, and the geochemistry of the gas suggests that it may be derived from the thermal alteration of algal matter. The submarine hydrothermal activity is negatively affecting abundances and diversity of infaunal assemblages. The carbon and nitrogen stable isotope ratios of some of the animals feeding around the vent, particularly the sea cucumber Holothuria inhabilis, were significantly different than those from the same species collected away from venting activity
Is It Science Yet?: Intelligent Design Creationism and the Constitution
On several occasions during the last eighty years, states have attempted to either prohibit the teaching of evolution in public school science classes or counter the teaching of evolution with mandatory references to the religious doctrine of creationism. The Supreme Court struck down examples of the first two generations of these statutes, holding that they violated the Establishment Clause of the First Amendment. A third generation of creationist legislation is now being proposed. Under this new generation of creationism legislation, science teachers would present so-called “intelligent design” theory as an alternative to evolution. Intelligent design theory asserts that a supernatural intelligence intervened in the natural world to dictate the nature and ordering of all biological species, which do not evolve from lower-to higher-order beings. This article considers whether these intelligent design creationism proposals can survive constitutional scrutiny. The authors analyze the religious, philosophical, and scientific details of intelligent design theory, and assess these details in light of the constitutional doctrine developed by the Court in its previous creationism decisions. The Article discusses several factors that pose problems for intelligent design theory, including the absence of objective scientific support for intelligent design, evidence of strong links between intelligent design and religious doctrine, the use of intelligent design to limit the dissemination of scientific theories that are perceived as contradicting religious teachings, and the fact that the irreducible core of intelligent design theory is what the Court has called the “manifestly religious concept of a God or Supreme Being. Based on these details, the authors conclude that intelligent design theory cannot survive scrutiny under the constitutional framework used by the Court to invalidate earlier creationism mandates
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Georeferencing the MacConnell Aerial Photo Collection
In the 1950s, Professor William P. MacConnell from the University of Massachusetts Forestry Department began working with his students to map the land cover in Massachusetts via the state’s earliest aerial photography program. These individual photographs are now part of the Special Collections and University Archives at the University of Massachusetts Amherst Libraries, and although they have been digitized and made available online, they have not yet been georeferenced.
In Spring 2021, our team (Alex and Matthew) began manually georeferencing the photos in ArcMap 10.8 software onto USGS 2019 color orthoimagery of Massachusetts available from MassGIS. Ideal ground control points include building corners, intersections, and any other distinctive features that have not resulted in much change between the historic and contemporary aerial photos. Some challenges we have faced include varying angles in which the photos were taken, cliffs that offset height in parts of the photo, or photos with a heavily forested area that makes georeferencing difficult to pinpoint ground control points.
The goal of the project is to georeference the approximately 4,800 individual photos from the 1951-52 series, which spans the entire state of Massachusetts, in order to make them available to the general public as downloadable GeoTIFFs. This result will allow anyone to access the photos and use them to analyze land-use changes in Massachusetts spanning the last 70 years. Manual georeferencing has come with its own challenges when encountering heavily forested aerial photos or aerial photos dominated by mostly urban areas. We find that future research into the potential automation of the georeferencing process would help alleviate the challenges associated with manual georeferencing
Transit times and mean ages for nonautonomous and autonomous compartmental systems
We develop a theory for transit times and mean ages for nonautonomous
compartmental systems. Using the McKendrick-von F\"orster equation, we show
that the mean ages of mass in a compartmental system satisfy a linear
nonautonomous ordinary differential equation that is exponentially stable. We
then define a nonautonomous version of transit time as the mean age of mass
leaving the compartmental system at a particular time and show that our
nonautonomous theory generalises the autonomous case. We apply these results to
study a nine-dimensional nonautonomous compartmental system modeling the
terrestrial carbon cycle, which is a modification of the Carnegie-Ames-Stanford
approach (CASA) model, and we demonstrate that the nonautonomous versions of
transit time and mean age differ significantly from the autonomous quantities
when calculated for that model
Cannibalism and infectious disease: Friends or foes?
© 2017 by The University of Chicago. Cannibalism occurs in a majority of both carnivorous and noncarnivorous animal taxa from invertebrates to mammals. Similarly, infectious parasites are ubiquitous in nature. Thus, interactions between cannibalism and disease occur regularly. While some adaptive benefits of cannibalism are clear, the prevailing view is that the risk of parasite transmission due to cannibalism would increase disease spread and, thus, limit the evolutionary extent of cannibalism throughout the animal kingdom. In contrast, surprisingly little attention has been paid to the other half of the interaction between cannibalism and disease, that is, how cannibalism affects parasites. Here we examine the interaction between cannibalism and parasites and show howadvances across independent lines of research suggest that cannibalism can also reduce the prevalence of parasites and, thus, infection risk for cannibals. Cannibalism does this by both directly killing parasites in infected victims and by reducing the number of susceptible hosts, often enhanced by the stage-structured nature of cannibalism and infection. While the well-established view that disease should limit cannibalism has held sway, we present theory and examples from a synthesis of the literature showing how cannibalism may also limit disease and highlight key areas where conceptual and empirical work is needed to resolve this debate
Technology ready use of single layer graphene as a transparent electrode for hybrid photovoltaic devices
Graphene has been used recently as a replacement for indium tin oxide (ITO)
for the transparent electrode of an organic photovoltaic device. Due to its
limited supply, ITO is considered as a limiting factor for the
commercialization of organic solar cells. We explored the use of large-area
graphene grown on copper by chemical vapor deposition (CVD) and then
transferred to a glass substrate as an alternative transparent electrode. The
transferred film was shown by scanning Raman spectroscopy measurements to
consist of >90% single layer graphene. Optical spectroscopy measurements showed
that the layer-transferred graphene has an optical absorbance of 1.23% at a
wavelength of 532 nm. We fabricated organic hybrid solar cells utilizing this
material as an electrode and compared their performance with ITO devices
fabricated using the same procedure. We demonstrated power conversion
efficiency up to 3.98%, higher than that of the ITO device (3.86%), showing
that layer-transferred graphene promises to be a high quality, low-cost,
flexible material for transparent electrodes in solar cell technology.Comment: 6 pages, 3 figure
Determining the Genetic Architecture of Reproductive Stage Drought Tolerance in Wheat Using a Correlated Trait and Correlated Marker Effect Model
Water stress during reproductive growth is a major yield constraint for wheat (Triticum aestivum L). We previously established a controlled environment drought tolerance phenotyping method targeting the young microspore stage of pollen development. This method eliminates stress avoidance based on flowering time. We substituted soil drought treatments by a reproducible osmotic stress treatment using hydroponics and NaCl as osmolyte. Salt exclusion in hexaploid wheat avoids salt toxicity, causing osmotic stress. A Cranbrook x Halberd doubled haploid (DH) population was phenotyped by scoring spike grain numbers of unstressed (SGNCon) and osmotically stressed (SGNTrt) plants. Grain number data were analyzed using a linear mixed model (LMM) that included genetic correlations between the SGNCon and SGNTrt traits. Viewing this as a genetic regression of SGNTrt on SGNCon allowed derivation of a stress tolerance trait (SGNTol). Importantly, and by definition of the trait, the genetic effects for SGNTol are statistically independent of those for SGNCon. Thus they represent non-pleiotropic effects associated with the stress treatment that are independent of the control treatment. QTL mapping was conducted using a whole genome approach in which the LMM included all traits and all markers simultaneously. The marker effects within chromosomes were assumed to follow a spatial correlation model. This resulted in smooth marker profiles that could be used to identify positions of putative QTL. The most influential QTL were located on chromosome 5A for SGNTol (126cM; contributed by Halberd), 5A for SGNCon (141cM; Cranbrook) and 2A for SGNTrt (116cM; Cranbrook). Sensitive and tolerant population tail lines all showed matching soil drought tolerance phenotypes, confirming that osmotic stress is a valid surrogate screening method
The psychiatric risk gene transcription factor 4 (TCF4) regulates neurodevelopmental pathways associated with schizophrenia, autism, and intellectual disability
Background Common genetic variants in and around the gene encoding transcription factor 4 (TCF4) are associated with an increased risk of schizophrenia. Conversely, rare damaging TCF4 mutations cause Pitt–Hopkins syndrome and have also been found in individuals with intellectual disability (ID) and autism spectrum disorder (ASD). Methods Chromatin immunoprecipitation and next generation sequencing were used to identify the genomic targets of TCF4. These data were integrated with expression, epigenetic and disease gene sets using a range of computational tools. Results We identify 10604 TCF4 binding sites in the genome that were assigned to 5437 genes. De novo motif enrichment found that most TCF4 binding sites contained at least one E-box (5′-CAtcTG). Approximately 77% of TCF4 binding sites overlapped with the H3K27ac histone modification for active enhancers. Enrichment analysis on the set of TCF4 targets identified numerous, highly significant functional clusters for pathways including nervous system development, ion transport and signal transduction, and co-expression modules for genes associated with synaptic function and brain development. Importantly, we found that genes harboring de novo mutations in schizophrenia (P = 5.3 × 10−7), ASD (P = 2.5 × 10−4), and ID (P = 7.6 × 10−3) were also enriched among TCF4 targets. TCF4 binding sites were also found at other schizophrenia risk loci including the nicotinic acetylcholine receptor cluster, CHRNA5/CHRNA3/CHRNB4 and SETD1A. Conclusions These data demonstrate that TCF4 binding sites are found in a large number of neuronal genes that include many genetic risk factors for common neurodevelopmental disorders
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