142 research outputs found
Developing fencing policies in dryland ecosystems
The daily energy requirements of animals are determined by a combination of physical and physiological factors, but food availability may challenge the capacity to meet nutritional needs. Western gorillas (Gorilla gorilla) are an interesting model for investigating this topic because they are folivore-frugivores that adjust their diet and activities to seasonal variation in fruit availability. Observations of one habituated group of western gorillas in Bai-Hokou, Central African Republic (December 2004-December 2005) were used to examine seasonal variation in diet quality and nutritional intake. We tested if during the high fruit season the food consumed by western gorillas was higher in quality (higher in energy, sugar, fat but lower in fibre and antifeedants) than during the low fruit season. Food consumed during the high fruit season was higher in digestible energy, but not any other macronutrients. Second, we investigated whether the gorillas increased their daily intake of carbohydrates, metabolizable energy (KCal/g OM), or other nutrients during the high fruit season. Intake of dry matter, fibers, fat, protein and the majority of minerals and phenols decreased with increased frugivory and there was some indication of seasonal variation in intake of energy (KCal/g OM), tannins, protein/fiber ratio, and iron. Intake of non-structural carbohydrates and sugars was not influenced by fruit availability. Gorillas are probably able to extract large quantities of energy via fermentation since they rely on proteinaceous leaves during the low fruit season. Macronutrients and micronutrients, but not digestible energy, may be limited for them during times of low fruit availability because they are hind-gut fermenters. We discuss the advantages of seasonal frugivores having large dietary breath and flexibility, significant characteristics to consider in the conservation strategies of endangered species
From bits to bites: Advancement of the Germinate platform to support prebreeding informatics for crop wild relatives
Management and distribution of experimental data from prebreeding projects
is important to ensure uptake of germplasm into breeding and research programs.
Being able to access and share this data in standard formats is essential.
The adoption of a common informatics platform for crops that may have limited
resources brings economies of scale, allowing common informatics components
to be used across multiple species. The close integration of such a platform with
commonly used breeding software, visualization, and analysis tools reduces the
barrier for entry to researchers and provides a common framework to facilitate
collaborations and data sharing. This work presents significant updates to the
Germinate platform and highlights its value in distributing prebreeding data for
14 crops as part of the project βAdapting Agriculture to Climate Change: Collecting,
Protecting and Preparing Crop Wild Relativesβ (hereafter Crop Trust Crop
Wild Relatives project) led by the Crop Trust (https://www.cwrdiversity.org). The
addition of data on these species compliments data already publicly available in
Germinate. We present a suite of updated Germinate features using examples
from these crop species and their wild relatives. The use of Germinate within the
Crop TrustCropWildRelatives project demonstrates the usefulness of the system
and the benefits a shared informatics platform provides. These data resources
provide a foundation on which breeding and research communities can develop
additional online resources for their crops, harness new data as it becomes available,
and benefit collectively from future developments of the Germinate platform
Photometric and Spectroscopic Studies of Massive Binaries in the Large Magellanic Cloud. I. Introduction and Orbits for Two Detached Systems: Evidence for a Mass Discrepancy?
The stellar mass-luminosity relation is poorly constrained by observations
for high mass stars. We describe our program to find eclipsing massive binaries
in the Magellanic Clouds using photometry of regions rich in massive stars, and
our spectroscopic follow-up to obtain radial velocities and orbits. Our
photometric campaign identified 48 early-type periodic variables, of which only
15 (31%) were found as part of the microlensing surveys. Spectroscopy is now
complete for 17 of these systems, and in this paper we present analysis of the
first two, LMC 172231 and ST2-28, simple detached systems of late-type O dwarfs
of relatively modest masses. Our orbit analysis yields very precise masses (2%)
and we use tomography to separate the components and determine effective
temperatures by model fitting, necessary for determining accurate (0.05-0.07
dex) bolometric luminosities in combination with the light-curve analysis. Our
approach allows more precise comparisons with evolutionary theory than
previously possible. To our considerable surprise, we find a small, but
significant, systematic discrepancy: all of the stars are slightly
under-massive, by typically 11% (or over-luminous by 0.2 dex) compared to that
predicted by the evolutionary models. We examine our approach for systematic
problems, but find no satisfactory explanation. The discrepancy is in the same
sense as the long-discussed and elusive discrepancy between the masses measured
from stellar atmosphere analysis with the stellar evolutionary models, and
might suggest that either increased rotation or convective overshooting is
needed in the models. Additional systems will be discussed in future papers of
this series, and will hopefully confirm or refute this trend.Comment: Accepted by the Astrophysical Journa
Aqueous hydroxylation mediated synthesis of crystalline calcium uranate particles
Metal uranates(VI) are solubility limiting U(VI) phases under high pH conditions and may act as suitable long-term wasteforms. The precipitation and thermal phase development mechanisms of calcium uranate particles formed via aqueous hydroxylation reactions are studied in order to address the lack of aqueous synthesis methods currently available. Hydrous Ca-deficient uranate particles formed from aqueous solutions saturated in U(VI) oligomers were found to thermally decompose via several weight-loss steps between 100 and 800 Β°C. Crystalline calcium uranate (Ca2U3O11) is initially formed at 700 Β°C via dehydration and dehydroxylation-olation reactions under redox-neutral conditions. This initial phase decomposes to biphasic CaUO4-UO2 particles at 800 Β°C via a reductive pathway
Enabling the Development and Deployment of Next Generation Point-of-Care Diagnostics
<p>Enabling the Development and Deployment of Next Generation Point-of-Care Diagnostics</p
Distinct populations of inflammatory fibroblasts and myofibroblasts in pancreatic cancer
Pancreatic stellate cells (PSCs) differentiate into cancer-associated fibroblasts (CAFs) that produce desmoplastic stroma, thereby modulating disease progression and therapeutic response in pancreatic ductal adenocarcinoma (PDA). However, it is unknown whether CAFs uniformly carry out these tasks or if subtypes of CAFs with distinct phenotypes in PDA exist. We identified a CAF subpopulation with elevated expression of alpha-smooth muscle actin (alphaSMA) located immediately adjacent to neoplastic cells in mouse and human PDA tissue. We recapitulated this finding in co-cultures of murine PSCs and PDA organoids, and demonstrated that organoid-activated CAFs produced desmoplastic stroma. The co-cultures showed cooperative interactions and revealed another distinct subpopulation of CAFs, located more distantly from neoplastic cells, which lacked elevated alphaSMA expression and instead secreted IL6 and additional inflammatory mediators. These findings were corroborated in mouse and human PDA tissue, providing direct evidence for CAF heterogeneity in PDA tumor biology with implications for disease etiology and therapeutic development
Recovery of a US Endangered Fish
BACKGROUND: More fish have been afforded US Endangered Species Act protection than any other vertebrate taxonomic group, and none has been designated as recovered. Shortnose sturgeon (Acipenser brevirostrum) occupy large rivers and estuaries along the Atlantic coast of North America, and the species has been protected by the US Endangered Species Act since its enactment. METHODOLOGY/PRINCIPAL FINDINGS: Data on the shortnose sturgeon in the Hudson River (New York to Albany, NY, USA) were obtained from a 1970s population study, a population and fish distribution study we conducted in the late 1990s, and a fish monitoring program during the 1980s and 1990s. Population estimates indicate a late 1990s abundance of about 60,000 fish, dominated by adults. The Hudson River population has increased by more than 400% since the 1970s, appears healthy, and has attributes typical for a long-lived species. Our population estimates exceed the government and scientific population recovery criteria by more than 500%, we found a positive trend in population abundance, and key habitats have remained intact despite heavy human river use. CONCLUSIONS/SIGNIFICANCE: Scientists and legislators have called for changes in the US Endangered Species Act, the Act is being debated in the US Congress, and the Act has been characterized as failing to recover species. Recovery of the Hudson River population of shortnose sturgeon suggests the combination of species and habitat protection with patience can yield successful species recovery, even near one of the world's largest human population centers
Mycobacterium tuberculosis Lineage Influences Innate Immune Response and Virulence and Is Associated with Distinct Cell Envelope Lipid Profiles
The six major genetic lineages of Mycobacterium tuberculosis are strongly associated with specific geographical regions, but their relevance to bacterial virulence and the clinical consequences of infection are unclear. Previously, we found that in Vietnam, East Asian/Beijing and Indo-Oceanic strains were significantly more likely to cause disseminated tuberculosis with meningitis than those from the Euro-American lineage. To investigate this observation we characterised 7 East Asian/Beijing, 5 Indo-Oceanic and 6 Euro-American Vietnamese strains in bone-marrow-derived macrophages, dendritic cells and mice. East Asian/Beijing and Indo-Oceanic strains induced significantly more TNF-Ξ± and IL-1Ξ² from macrophages than the Euro-American strains, and East Asian/Beijing strains were detectable earlier in the blood of infected mice and grew faster in the lungs. We hypothesised that these differences were induced by lineage-specific variation in cell envelope lipids. Whole lipid extracts from East Asian/Beijing and Indo-Oceanic strains induced higher concentrations of TNF-Ξ± from macrophages than Euro-American lipids. The lipid extracts were fractionated and compared by thin layer chromatography to reveal a distinct pattern of lineage-associated profiles. A phthiotriol dimycocerosate was exclusively produced by East Asian/Beijing strains, but not the phenolic glycolipid previously associated with the hyper-virulent phenotype of some isolates of this lineage. All Indo-Oceanic strains produced a unique unidentified lipid, shown to be a phenolphthiocerol dimycocerosate dependent upon an intact pks15/1 for its production. This was described by Goren as the βattenuation indictor lipidβ more than 40 years ago, due to its association with less virulent strains from southern India. Mutation of pks15/1 in a representative Indo-Oceanic strain prevented phenolphthiocerol dimycocerosate synthesis, but did not alter macrophage cytokine induction. Our findings suggest that the early interactions between M. tuberculosis and host are determined by the lineage of the infecting strain; but we were unable to show these differences are driven by lineage-specific cell-surface expressed lipids
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