2,614 research outputs found
The Real Snowbirds of South Florida: Using Citizen Science to Assess the Ranges of South Florida\u27s Overwintering Birdsh
The overwintering ranges of North American bird populations are shifting and the winter ranges of south Florida’s landbirds remain understudied. Expert-drawn range maps used for scientific studies and environmental public policy could therefore be depicting inaccurate ranges for many migratory birds. This study used citizen science data from eBird (2001–2017) to evaluate patterns in overwintering avian species richness and identify discrepanciesin expert-drawn species range maps for overwintering passerines in south Florida. Most of Florida’s overwintering bird species were sighted in south Florida. Of the species observed there between 2001 and 2017, 66% had range map discrepancies. Fifteen target species were examined in the present study and fourteen of them were sighted in south Florida throughout the winter. None of these were depicted on range maps as overwinterers. These results showed that current expert-drawn range maps likely misrepresent the current winter ranges of passerine species in south Florida
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Evaluating and optimizing oral formulations of live bacterial vaccines using a gastro-small intestine model
Gastrointestinal (GI) models that mimic physiological conditions in vitro are important tools for developing and optimizing biopharmaceutical formulations. Oral administration of live attenuated bacterial vaccines (LBV) can safely and effectively promote mucosal immunity but new formulations are required that provide controlled release of optimal numbers of viable bacterial cells, which must survive gastrointestinal transit overcoming various antimicrobial barriers. Here, we use a gastro-small intestine gut model of human GI conditions to study the survival and release kinetics of two oral LBV formulations: the licensed typhoid fever vaccine Vivotif comprising enteric coated capsules; and an experimental formulation of the model vaccine Salmonella Typhimurium SL3261 dried directly onto cast enteric polymer films and laminated to form a polymer film laminate (PFL). Neither formulation released significant numbers of viable cells when tested in the complete gastro-small intestine model. The poor performance in delivering viable cells could be attributed to a combination of acid and bile toxicity plus incomplete release of cells for Vivotif capsules, and to bile toxicity alone for PFL. To achieve effective protection from intestinal bile in addition to effective acid resistance, bile adsorbent resins were incorporated into the PFL to produce a new formulation, termed BR-PFL. Efficient and complete release of 4.4x107 live cells per dose was achieved from BR-PFL at distal intestinal pH, with release kinetics controlled by the composition of the enteric polymer film, and no loss in viability observed in any stage of the GI model. Use of this in vitro GI model thereby allowed rational design of an oral LBV formulation to maximize viable cell release
Mixed Quantum/Classical Approach for Description of Molecular Collisions in Astrophysical Environments
An efficient and accurate mixed quantum/classical theory approach for computational treatment of inelastic scattering is extended to describe collision of an atom with a general asymmetric-top rotor polyatomic molecule. Quantum mechanics, employed to describe transitions between the internal states of the molecule, and classical mechanics, employed for description of scattering of the atom, are used in a self-consistent manner. Such calculations for rotational excitation of HCOOCH3 in collisions with He produce accurate results at scattering energies above 15 cm–1, although resonances near threshold, below 5 cm–1, cannot be reproduced. Importantly, the method remains computationally affordable at high scattering energies (here up to 1000 cm–1), which enables calculations for larger molecules and at higher collision energies than was possible previously with the standard full-quantum approach. Theoretical prediction of inelastic cross sections for a number of complex organic molecules observed in space becomes feasible using this new computational tool
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The APOE ε4 allele is associated with a reduction in FEV1/FVC in women: A cross-sectional analysis of the Long Life Family Study
Introduction
Murine studies have shown that apolipoprotein E modulates pulmonary function during development, aging, and allergen-induced airway disease. It is not known whether the polymorphic human APOE gene influences pulmonary function.
Objectives
We assessed whether an association exists between the polymorphic human APOE ε2, ε3, and ε4 alleles and pulmonary function among participants in the Long Life Family Study.
Methods
Data from 4,468 Caucasian subjects who had genotyping performed for the APOE ε2, ε3, and ε4 alleles were analyzed, with and without stratification by sex. Statistical models were fitted considering the effects of the ε2 allele, defined as ε2/2 or ε2/3 genotypes, and the ε4 allele, defined as ε3/4 or ε4/4 genotypes, which were compared to the ε3/3 genotype.
Results
The mean FEV1/FVC ratio (the forced expiratory volume in one second divided by the forced vital capacity) was lower among women with the ε4 allele as compared to women with the ε3/3 genotype or the ε2 allele. Carriage of the APOE ε4 allele was associated with FEV1/FVC, which implied lower values. Further analysis showed that the association primarily reflected women without lung disease who were older than 70 years. The association was not mediated by lipid levels, smoking status, body mass index, or cardiovascular disease.
Conclusions
This study for the first time identifies that the APOE gene is associated with modified lung physiology in women. This suggests that a link may exist between the APOE ε4 allele, female sex, and a reduction in the FEV1/FVC ratio in older individuals
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A laminated polymer film formulation for enteric delivery of live vaccine and probiotic bacteria
Live bacterial cells (LBC) are administered orally as attenuated vaccines, to deliver biopharmaceutical agents, and as probiotics to improve gastrointestinal health. However, LBC present unique formulation challenges and must survive gastrointestinal antimicrobial defenses including gastric acid after administration. We present a simple new formulation concept, termed Polymer Film Laminate (PFL). LBC are ambient dried onto cast acid-resistant enteric polymer films that are then laminated together to produce a solid oral dosage form. LBC of a model live bacterial vaccine and a probiotic were dried directly onto a cast film of enteric polymer. The effectiveness at protecting dried cells in a simulated gastric fluid (pH 2.0) depended on the composition of enteric polymer film used, with a blend of ethylcellulose plus Eudragit L100 55 providing greater protection from acid than Eudragit alone. However, although PFL made from blended polymers films completely released low molecular weight dye into intestinal conditions (pH 7.0), they failed to release LBC. In contrast, PFL made from Eudragit alone successfully protected dried probiotic or vaccine LBC from simulated gastric fluid for 2h, and subsequently released all viable cells within 60min of transfer into simulated intestinal fluid. Release kinetics could be controlled by modifying the lamination method
Hydration interactions: aqueous solvent effects in electric double layers
A model for ionic solutions with an attractive short-range pair interaction
between the ions is presented. The short-range interaction is accounted for by
adding a quadratic non-local term to the Poisson-Boltzmann free energy. The
model is used to study solvent effects in a planar electric double layer. The
counter-ion density is found to increase near the charged surface, as compared
with the Poisson-Boltzmann theory, and to decrease at larger distances. The ion
density profile is studied analytically in the case where the ion distribution
near the plate is dominated only by counter-ions. Further away from the plate
the density distribution can be described using a Poisson-Boltzmann theory with
an effective surface charge that is smaller than the actual one.Comment: 11 Figures in 13 files + LaTex file. 20 pages. Accepted to Phys. Rev.
E. Corrected typos and reference
Examining the quality and management of non-geometric building information modelling data at project hand-over
Through the exponential global increase of Building Information Modelling (BIM) adoption across the Construction industry, and the emergence of inter-connected, strategic and data-rich solutions; such as Big Data, the Internet of Things and Smart Cities, the importance associated with activities and decisions reliant on exact data input, transaction, analysis, and resulting actions becomes exponentially magnified. The supply of inaccurate BIM data may negatively impact on systems and processes that require fully assured data of appropriate quality/veracity, to support informed decision making, deliver functionality, facilitate services, or direct strategic actions within the built environment. This preliminary research intends to provide a catalyst for discussion, analysis and information retrieval relating to Building Information Modelling (BIM) processes where non-geometric data errors may; or are predicted to occur within a project environment. This may result in the delivery of data that cannot be described as representing truth or of good quality, and therefore of little value or use to the data user. The wider aspects of this research investigates specifically non-geometric data veracity & associated dimensions of data quality; in order to discover and explore future solutions to resolve current industry data quality assessment challenges. This paper provides feedback from the research focusing on the current state, presenting existing industry challenges and proposes further research areas based on initial findings
Black Holes in the Early Universe
The existence of massive black holes was postulated in the sixties, when the
first quasars were discovered. In the late nineties their reality was proven
beyond doubt, in the Milky way and a handful nearby galaxies. Since then,
enormous theoretical and observational efforts have been made to understand the
astrophysics of massive black holes. We have discovered that some of the most
massive black holes known, weighing billions of solar masses, powered luminous
quasars within the first billion years of the Universe. The first massive black
holes must therefore have formed around the time the first stars and galaxies
formed. Dynamical evidence also indicates that black holes with masses of
millions to billions of solar masses ordinarily dwell in the centers of today's
galaxies. Massive black holes populate galaxy centers today, and shone as
quasars in the past; the quiescent black holes that we detect now in nearby
bulges are the dormant remnants of this fiery past. In this review we report on
basic, but critical, questions regarding the cosmological significance of
massive black holes. What physical mechanisms lead to the formation of the
first massive black holes? How massive were the initial massive black hole
seeds? When and where did they form? How is the growth of black holes linked to
that of their host galaxy? Answers to most of these questions are work in
progress, in the spirit of these Reports on Progress in Physics.Comment: Reports on Progress in Physics, in pres
Twenty five years after KLS: A celebration of non-equilibrium statistical mechanics
When Lenz proposed a simple model for phase transitions in magnetism, he
couldn't have imagined that the "Ising model" was to become a jewel in field of
equilibrium statistical mechanics. Its role spans the spectrum, from a good
pedagogical example to a universality class in critical phenomena. A quarter
century ago, Katz, Lebowitz and Spohn found a similar treasure. By introducing
a seemingly trivial modification to the Ising lattice gas, they took it into
the vast realms of non-equilibrium statistical mechanics. An abundant variety
of unexpected behavior emerged and caught many of us by surprise. We present a
brief review of some of the new insights garnered and some of the outstanding
puzzles, as well as speculate on the model's role in the future of
non-equilibrium statistical physics.Comment: 3 figures. Proceedings of 100th Statistical Mechanics Meeting,
Rutgers, NJ (December, 2008
Angular Momentum and the Formation of Stars and Black Holes
The formation of compact objects like stars and black holes is strongly
constrained by the requirement that nearly all of the initial angular momentum
of the diffuse material from which they form must be removed or redistributed
during the formation process. The mechanisms that may be involved and their
implications are discussed for (1) low-mass stars, most of which probably form
in binary or multiple systems; (2) massive stars, which typically form in
clusters; and (3) supermassive black holes that form in galactic nuclei. It is
suggested that in all cases, gravitational interactions with other stars or
mass concentrations in a forming system play an important role in
redistributing angular momentum and thereby enabling the formation of a compact
object. If this is true, the formation of stars and black holes must be a more
complex, dynamic, and chaotic process than in standard models. The
gravitational interactions that redistribute angular momentum tend to couple
the mass of a forming object to the mass of the system, and this may have
important implications for mass ratios in binaries, the upper stellar IMF in
clusters, and the masses of supermassive black holes in galaxies.Comment: Accepted by Reports on Progress in Physic
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