734 research outputs found
A user’s manual for finite difference synthetic seismogram codes on the CYBER 205 and CRAY XMP-12
Over the past eight years, a software package has been developed to solve
the elastic wave equation by the method of finite differences (Hunt et al.,
1983; Stephen, 1983; Stephen, 1984a; Stephen, 1984b; Nicoletis, 1981). The
elastic wave equation can be solved in two dimensions for point sources in
cylindrical coordinates or line sources in rectangular coordinates.
Compressional and shear velocity and density are allowed to vary both
vertically and radially.
Since the code is very computationally intensive for realistic size
models, it has been implemented on two Class VI super computers: the Cyber 205
at Purdue University and the Cray XMP-l2 at the Naval Research Laboratory.
This technical report is a user's manual for running the code on these
machines. It is assumed that the reader is already familiar with running the
code on the VAX ll-780 (Hunt et al., 1983).Funding was provided by the National Science Foundation under grant Nos. OCE-811 7571 and OCE-8409155; and by the Office of
Naval Research under contract No. N00014-85-C-001NR
FINDIF : a software package to create synthetic seismograms by finite differences
In order to study seismic wave propagation through laterally varying
sea floor structures, a software package has been created to generate synthetic
seismograms by finite differences. The elastic wave equation can be
solved in two dimensions either for point sources in cylindrical coordinates
or for line sources in rectangular coordinates. Vertical and radial variations
of the elastic parameters are allowed.
The package includes four programs. Input to the system consists of a
short file containing parameter values to describe the model. The first program
is used to initialize the system for the particular model being used.
The source arrays and velocity matrices are each computed by a separate program.
The final program, which actually carries out the finite difference
calculations, includes six subroutines to implement different options based on
alternative finite difference formulations. Two different kinds of output
files are created by this program: one or more snap-shot files, and one time
series file, which will usually include more than one series.Funding was provided by the Office of Naval Research
under Contract N00014-79-C-0071; NR 083-004
Chromosomal integration of an avian oncogenic herpesvirus reveals telomeric preferences and evidence for lymphoma clonality
Abstract Background Herpesviruses are a major health concern for numerous organisms, including humans, causing both acute and chronic infections recurrent over an individual's lifespan. Marek's disease virus (MDV) is a highly contagious herpesvirus which causes a neoplastic condition in chicken populations. Several vertebrate-infecting herpesviruses have been shown to exist in an integrated state during latent periods of infection. However the status of MDV during latency has been a topic of debate. Results Here we employed high-resolution multi-color fluorescence in situ hybridization (FISH) to show integration of MDV at the telomeres of chicken chromosomes. Cytogenomic mapping of the chromosomal integrations allowed us to examine the clonal relationships among lymphomas within individuals, whereas analysis of tumors from multiple individuals indicated the potential for chromosomal preferences. Conclusions Our data highlight that substantive genome-level interactions between the virus and host exist, and merit consideration for their potential impact and role in key aspects of herpesvirus pathobiology including infection, latency, cellular transformation, latency-breaks and viral evolution
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Multiple Health Behavior Changes in a Cancer Prevention Intervention for Construction Workers, 2001-2003
Introduction: Few multiple behavior change interventions have addressed tobacco use in conjunction with fruit and vegetable consumption, particularly among high-risk blue-collar workers. Tools for Health, a cancer prevention intervention for construction laborers, was effective in achieving behavior change for smoking cessation and fruit and vegetable consumption separately. This study examines whether addressing smoking and fruit and vegetable consumption was successful in achieving positive change for both behaviors. We also explored possible explanations for the relationship between behavior changes in these 2 behavioral domains. Methods: We retrospectively analyzed data from a randomized controlled trial testing a smoking cessation and fruit and vegetable consumption intervention for construction workers. We used survey data from 300 intervention participants to answer our primary research question: Did participants who reported being smokers at baseline successfully quit smoking and increase their fruit and vegetable consumption by the end of the intervention? We used qualitative data from 16 small group discussions to help interpret these results. Results: Tools for Health participants achieved substantial levels of smoking cessation and increased their fruit and vegetable consumption, concurrently, during the course of the intervention. Conclusion: This study provides evidence that pairing smoking cessation with increasing fruit and vegetable consumption can be successful in a multiple behavior change intervention designed for high-risk blue-collar workers. Further, our findings provide potential directions for examining why this pairing might be complementary
An acoustic navigation system
This report describes a system for underwater acoustic
navigation developed, and in use, at the Woods Hole Oceanographic
Institution. It includes a brief discussion of the electronic
components, operation, mathematical analysis, and available computer
programs. There is a series of supplementary Technical Memoranda
containing more information on various aspects of the system. We believe that this kind of documentation is more
flexible and better meets the needs of potential users than including
all technical details in one large volume. These are not final or
definitive reports; acoustic navigation capabilities will continue
to evolve at W.H.O.I. for some time.
Acoustic navigation provides a method of tracking a ship, and an
underwater vehicle or instrument package (‘fish’), in the deep ocean.
Acoustic devices attached to the ship and fish measure the length of
time it takes a sound pulse to travel to acoustic transponders moored
on the ocean floor. If the transponder positions and the average
speed of sound are known, the ship or fish position can be found.Prepared for the Office of Naval Research
under Contracts N00014-71-C0284; NR 293-008
N00014-70-C0205; NR 263-103 and the National
Science Foundation/International Decade of
Ocean Exploration Grant GX-36024 and the
Applied Physics Laboratory of The Johns
Hopkins University Contract 372111
Only Yes Means Yes: Sexual Coercion in Rural Adolescent Relationships
Purpose
Sexual consent is important to healthy relationships; however, sexual coercion is common. We examine modifiable risk and protective factors for sexual coercion among high school students in a rural community.
Methods
We surveyed 10th graders (N = 442) in a rural, Midwestern, low-to-middle income county before receiving an evidence-based sex education program. Sexual coercion was a single item, “has anyone you were dating or going out with forced you to do sexual things that you did not want to do?” We examined associations between sexual coercion and demographics, risk behaviors, sexual self-efficacy, controlling relationship behaviors, parent communication, and adverse childhood experiences.
Results
Approximately 22% of females and 8% of males reported experiencing sexual coercion at least once in their lifetime. Gender differences emerged in associated risk and protective factors, including sexual sex efficacy, controlling relationship behaviors, parent–adolescent communication about sex, and adverse childhood experiences.
Conclusions
Sexual coercion is common among adolescents in rural communities. Prevention interventions should target modifiable risk and protective factors
Effects of climate change and anthropogenic modification on a disturbance-dependent species in a large riverine system
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 8 (2017): e01653, doi:10.1002/ecs2.1653.Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the persistence of metapopulations of early-successional species under both suppressed disturbance regimes and disturbance regimes where climate change has further altered disturbance frequency or scope.Nebraska Environmental Trust
Nebraska State Wildlife Grant Program;
Nebraska Wildlife Conservation Fund;
U.S. Army Corps of Engineers;
U.S. Fish and Wildlife Service (USFWS);
USFWS North Atlantic Landscape Conservation Cooperative;
Virginia Tec
Effects of climate change and anthropogenic modification on a disturbance-dependent species in a large riverine system
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 8 (2017): e01653, doi:10.1002/ecs2.1653.Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the persistence of metapopulations of early-successional species under both suppressed disturbance regimes and disturbance regimes where climate change has further altered disturbance frequency or scope.Nebraska Environmental Trust
Nebraska State Wildlife Grant Program;
Nebraska Wildlife Conservation Fund;
U.S. Army Corps of Engineers;
U.S. Fish and Wildlife Service (USFWS);
USFWS North Atlantic Landscape Conservation Cooperative;
Virginia Tec
Effects of climate change and anthropogenic modification on a disturbance-dependent species in a large riverine system
Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the persistence of metapopulations of early-successional species under both suppressed disturbance regimes and disturbance regimes where climate change has further altered disturbance frequency or scope
Ecosystem-bedrock interaction changes nutrient compartmentalization during early oxidative weathering
Ecosystem-bedrock interactions power the biogeochemical cycles of Earth's
shallow crust, supporting life, stimulating substrate transformation, and
spurring evolutionary innovation. While oxidative processes have dominated half
of terrestrial history, the relative contribution of the biosphere and its
chemical fingerprints on Earth's developing regolith are still poorly
constrained. Here, we report results from a two-year incipient weathering
experiment. We found that the mass release and compartmentalization of major
elements during weathering of granite, rhyolite, schist and basalt was
rock-specific and regulated by ecosystem components.
A tight interplay between physiological needs of different biota, mineral
dissolution rates, and substrate nutrient availability resulted in intricate
elemental distribution patterns. Biota accelerated CO2 mineralization over
abiotic controls as ecosystem complexity increased, and significantly modified
stoichiometry of mobilized elements. Microbial and fungal components inhibited
element leaching (23.4% and 7%), while plants increased leaching and biomass
retention by 63.4%. All biota left comparable biosignatures in the dissolved
weathering products. Nevertheless, the magnitude and allocation of weathered
fractions under abiotic and biotic treatments provide quantitative evidence for
the role of major biosphere components in the evolution of upper continental
crust, presenting critical information for large-scale biogeochemical models
and for the search for stable in situ biosignatures beyond Earth.Comment: 41 pages (MS, SI and Data), 16 figures (MS and SI), 6 tables (SI and
Data). Journal article manuscrip
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