348 research outputs found
Geodatabase Development to Support Hyperspectral Imagery Exploitation
Geodatabase development for coastal studies conducted by the Naval Research Laboratory (NRL) is essential to support the exploitation of hyperspectral imagery (HSI). NRL has found that the remote sensing and mapping science community benefits from coastal classifications that group coastal types based on similar features. Selected features in project geodatabases relate to significant biological and physical forces that shape the coast. The project geodatabases help researchers understand factors that are necessary for imagery post processing, especially those features having a high degree of temporal and spatial variability. NRL project geodatabases include a hierarchy of environmental factors that extend from shallow water bottom types and beach composition to inland soil and vegetation characteristics. These geodatabases developed by NRL allow researchers to compare features among coast types. The project geodatabases may also be used to enhance littoral data archives that are sparse. This paper highlights geodatabase development for recent remote sensing experiments in barrier island, coral, and mangrove coast types
Orbital dependent nucleonic pairing in the lightest known isotopes of tin
By studying the 109Xe-->105Te-->101Sn superallowed alpha-decay chain, we
observe low-lying states in 101Sn, the one-neutron system outside doubly magic
100Sn. We find that the spins of the ground state (J = 7=2) and first excited
state (J = 5=2) in 101Sn are reversed with respect to the traditional level
ordering postulated for 103Sn and the heavier tin isotopes. Through simple
arguments and state-of-the-art shell model calculations we explain this
unexpected switch in terms of a transition from the single-particle regime to
the collective mode in which orbital-dependent pairing correlations, dominate.Comment: 5 pages 3 figure
Quantum key distribution with 1.25 Gbps clock synchronization
We have demonstrated the exchange of sifted quantum cryptographic key over a
730 meter free-space link at rates of up to 1.0 Mbps, two orders of magnitude
faster than previously reported results. A classical channel at 1550 nm
operates in parallel with a quantum channel at 845 nm. Clock recovery
techniques on the classical channel at 1.25 Gbps enable quantum transmission at
up to the clock rate. System performance is currently limited by the timing
resolution of our silicon avalanche photodiode detectors. With improved
detector resolution, our technique will yield another order of magnitude
increase in performance, with existing technology.Comment: 6 pages, 3 figures, 99 kB .pdf documen
Solitary waves in the Nonlinear Dirac Equation
In the present work, we consider the existence, stability, and dynamics of
solitary waves in the nonlinear Dirac equation. We start by introducing the
Soler model of self-interacting spinors, and discuss its localized waveforms in
one, two, and three spatial dimensions and the equations they satisfy. We
present the associated explicit solutions in one dimension and numerically
obtain their analogues in higher dimensions. The stability is subsequently
discussed from a theoretical perspective and then complemented with numerical
computations. Finally, the dynamics of the solutions is explored and compared
to its non-relativistic analogue, which is the nonlinear Schr{\"o}dinger
equation. A few special topics are also explored, including the discrete
variant of the nonlinear Dirac equation and its solitary wave properties, as
well as the PT-symmetric variant of the model
Relative validity of the Planetary Health Diet Index by comparison with usual nutrient intakes, plasma food consumption biomarkers, and adherence to the Mediterranean diet among European adolescents: the HELENA study
Purpose
The EAT-Lancet Commission proposed an evidence-based global reference diet to improve human health within planetary boundaries. Recently, the Planetary Health Diet Index (PHDI) was developed based on the EAT-Lancet recommendations and validated among Brazilian adults. However, the relative validity of the PHDI in adolescents has yet to be assessed. Thus, we aimed to evaluate the relative validity of the PHDI in European adolescents.
Methods
We used cross-sectional data from 1804 adolescents (12.5–17.5 years) enrolled in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. The PHDI (0–150 points) was calculated based on dietary intake data from two non-consecutive 24-h dietary recalls. Associations between the PHDI and usual nutrient intakes, plasma food consumption biomarkers, and adherence to the Mediterranean diet were evaluated using multivariable-adjusted mixed-effects linear regression models.
Results
Higher PHDI score was associated with greater intakes of nutrients predominantly from plant-source foods, such as vegetable protein, vitamin E, and folate and with lower intake of nutrients predominately from animal-source foods, such as total and saturated fat, cholesterol, and animal protein. Furthermore, a higher PHDI score was also positively associated with plasma β-carotene, vitamin C, vitamin D, folate, and ferritin concentrations, while negatively associated with trans-fatty acids concentration. Moreover, higher PHDI was related to a greater adherence to the Mediterranean dietary pattern.
Conclusions
The PHDI showed good relative validity among adolescents in the HELENA study. Hence, future research should assess adherence to the PHDI and long-term health outcomes
Beta-strength and anti-neutrino spectra from total absorption spectroscopy of a decay chain \u3csup\u3e142\u3c/sup\u3eCs→\u3csup\u3e142\u3c/sup\u3e Ba →\u3csup\u3e142\u3c/sup\u3eLa
Beta decays of mass A = 142 isobaric chain starting from 142Cs have been investigated by means of Modular Total Absorption Spectrometer (MTAS) and on-line mass separation at Oak Ridge National Laboratory. The beta strength distribution derived for 142Cs decay from MTAS spectra is showing significant differences in β-feeding pattern when compared to the values listed at nuclear databases. MTAS results are shifting the associated anti-neutrino energy spectrum towards lower energies. A decay pattern deduced for 142Ba is similar to earlier reported results
Single-molecule experiments in biological physics: methods and applications
I review single-molecule experiments (SME) in biological physics. Recent
technological developments have provided the tools to design and build
scientific instruments of high enough sensitivity and precision to manipulate
and visualize individual molecules and measure microscopic forces. Using SME it
is possible to: manipulate molecules one at a time and measure distributions
describing molecular properties; characterize the kinetics of biomolecular
reactions and; detect molecular intermediates. SME provide the additional
information about thermodynamics and kinetics of biomolecular processes. This
complements information obtained in traditional bulk assays. In SME it is also
possible to measure small energies and detect large Brownian deviations in
biomolecular reactions, thereby offering new methods and systems to scrutinize
the basic foundations of statistical mechanics. This review is written at a
very introductory level emphasizing the importance of SME to scientists
interested in knowing the common playground of ideas and the interdisciplinary
topics accessible by these techniques. The review discusses SME from an
experimental perspective, first exposing the most common experimental
methodologies and later presenting various molecular systems where such
techniques have been applied. I briefly discuss experimental techniques such as
atomic-force microscopy (AFM), laser optical tweezers (LOT), magnetic tweezers
(MT), biomembrane force probe (BFP) and single-molecule fluorescence (SMF). I
then present several applications of SME to the study of nucleic acids (DNA,
RNA and DNA condensation), proteins (protein-protein interactions, protein
folding and molecular motors). Finally, I discuss applications of SME to the
study of the nonequilibrium thermodynamics of small systems and the
experimental verification of fluctuation theorems. I conclude with a discussion
of open questions and future perspectives.Comment: Latex, 60 pages, 12 figures, Topical Review for J. Phys. C (Cond.
Matt
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Nature and mental health: An ecosystem service perspective
A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so
Genetic analysis of male reproductive success in relation to density in the zebrafish, Danio rerio
BACKGROUND: We used behavioural and genetic data to investigate the effects of density on male reproductive success in the zebrafish, Danio rerio. Based on previous measurements of aggression and courtship behaviour by territorial males, we predicted that they would sire more offspring than non-territorial males. RESULTS: Microsatellite analysis of paternity showed that at low densities territorial males had higher reproductive success than non-territorial males. However, at high density territorial males were no more successful than non-territorials and the sex difference in the opportunity for sexual selection, based on the parameter I(mates), was low. CONCLUSION: Male zebrafish exhibit two distinct mating tactics; territoriality and active pursuit of females. Male reproductive success is density dependent and the opportunity for sexual selection appears to be weak in this species
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