684 research outputs found
Remote sensing in the coastal and marine environment. Proceedings of the US North Atlantic Regional Workshop
Presentations were grouped in the following categories: (1) a technical orientation of Earth resources remote sensing including data sources and processing; (2) a review of the present status of remote sensing technology applicable to the coastal and marine environment; (3) a description of data and information needs of selected coastal and marine activities; and (4) an outline of plans for marine monitoring systems for the east coast and a concept for an east coast remote sensing facility. Also discussed were user needs and remote sensing potentials in the areas of coastal processes and management, commercial and recreational fisheries, and marine physical processes
Prescribed Fire and Oak Sapling Physiology, Demography and Folivore Damage in an Ozark Woodland
Proceedings from the 2014 Central Hardwood Forest Conference in Carbondale, IL. The published proceedings include 27 papers and 47 abstracts pertaining to research conducted on biofuels and bioenergy, forest biometrics, forest ecology and physiology, forest economics, forest health including invasive species, forest soils and hydrology, geographic information systems, harvesting and utilization, silviculture, and wildlife management
The Value of Comparative Animal Research : Krogh’s Principle Facilitates Scientific Discoveries
There are no conflicts of interest to declare. This paper developed from the 2016 Early Career Impact Award from the Federation of Associations in Behavioral & Brain Sciences to TJS. TJS has received funding from The Leverhulme Trust. FJPE is in receipt of funding from the BBSRC (BB/M001555/1). The National Institutes of Health has funded RDF (NS 034950, NS093277, NIMH 087930), AGO (HD079573, IOS-1354760) and AMK (HD081959). BAA is an Arnold O. Beckman postdoctoral fellow.Peer reviewedPostprin
Missing physics in stick-slip dynamics of a model for peeling of an adhesive tape
It is now known that the equations of motion for the contact point during
peeling of an adhesive tape mounted on a roll introduced earlier are singular
and do not support dynamical jumps across the two stable branches of the peel
force function. By including the kinetic energy of the tape in the Lagrangian,
we derive equations of motion that support stick-slip jumps as a natural
consequence of the inherent dynamics. In the low mass limit, these equations
reproduce solutions obtained using a differential-algebraic algorithm
introduced for the earlier equations. Our analysis also shows that mass of the
ribbon has a strong influence on the nature of the dynamics.Comment: Accepted for publication in Phys. Rev. E (Rapid Communication
Tidal circulation and flushing characteristics of the Nauset Marsh System : report to the Town of Orleans
Various interested bodies (i.e., National Park Servce, Cape Cod Commssion, and the
Town of Orleans) charged with management of the Nauset Marsh system on Cape Cod, MA,
commissioned a study of the estuarine circulation within the Nauset system. Recent signficant
morphological changes in the system have changed mixing processes and residence times for the
embayment. This study specifically addressed the differing water circulation and residence times
arising from a migrating single inlet (dominant condition) and dual inlet (1992-1996) situations.
These residence times are to be used by the Cape Cod Commission to identify nitrogen-sensitive
sub-embayments based on various assumptions of build-out and nutrient loading. The Nauset
Marsh system has experienced considerable development in recent years; proper management of
this resource area requires knowledge of the consequences of such development.
Application of field observations of bathymetry, sea surface elevation, temperature,
salinity and currents, leads to better understanding the physics of the system. These data,
analyzed in various forms, served as input data for a numerical, two-dimensional circulation
model of the embayment. The circulation model provided flow and discharge data with which the
residence times were calculated. Bathymetric measurements defined the volumes of the various
sub-embayments to be used in the calculation of residence times.
Residence times were calculated for six sub-embayments of the system, defined on the
basis of their common hydrodynamic and morphologic characteristics. Two scenarios were
evaluated: one for the present single-inlet system, which is near typical for most system states,
and one for a dual inlet system such as existed for a period of time from 1992 through 1996.
Residence times were evaluated for twelve cases, to demonstrate the range of residence
times that can be defined based on varing assumptions. For instance, residence times can be
defined on the basis of mean low water volumes or mean water levels, the latter being the more
conservative (yielding a longer residence time). In addition, residence times depend on whether
spring tides, neap tides, or average tidal conditions are used. We provide data on all three
conditions: the neap tidal case is the most conservative in the sense of providing a longer
residence time. This case can serve as the basis for flushing if conservatism is desired. Finally,
residence time can be defined based on the amount of time it takes for water to renew itself with
water from adjacent sub-embayments, or more conservatively assuming renewal from the
offshore waters (which are presumed to be cleaner).
Based on these various inputs, assumptions and calculations, residence times for Salt and
Mill ponds under conditions of a single inlet are the longest of the various sub-embayments.
Town Cove is still relatively quickly renewed, though not as fast as the main channels serving the
system.
Flow pattern under dual-inlet condition does seem to be partioned well, with the
northern inlet serving the northern part of the system and the southern inlet serving the southern
part of the system, with litte hydrodynamc communication between the two divisions. This
new hydrodynamc behavior results in shorter residence times under dual inlets than under a
single inlet.
Calculations indicate that the slowest flushing occurs in Mill and Salt ponds. The main
body of the embayment, consisting of narrow channels between well-flushed salt marsh and tidal
flats, flushes rapidly. Two-dimensional calculations show that Town Cove also flushes
relatively rapidly, on average. However, its greater depth and occasional temperature
stratification create conditions which might accumulate nutrients in bottom sediments, which,
when released, can cause decrease in water quality (such as plankton blooms). A more
sophisticated low-trophic level ecosystem model combined with vertical hydrodynamic structure
could clarfy the dynamics of this process.
This study provides a defensible basis for evaluating nutrient loading and potential
eutrophication arising from development in the watershed around Nauset embayment. However,
since morphological changes occur on a rapid basis in this area, the issue of residence time should
be re-examined periodically. For instance, rapid onshore migration of the southern barrier beach
is threatening closure of the south chanel, a condition which could adversely affect water quality
in Nauset Harbor in the near futue. A process should be established to examine the sensitivity
of residence times for rapidly changing morphology.Funding was provided by the Town of Orleans, the National Park Service
and the Andrew W. Mellon Foundation
Extraterrestrial Amino Acids in the Almahata Sitta Meteorite
Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, R-amino-n-butyric acid (beta-ABA), 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L approximately 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha-aminoisobutyric acid (alpha-AIB), 4-amino-2- methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and alpha-AIB in Almahata Sitta are 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures
AMINO ACID ANALYSES OF THE ANTARCTIC CM2 METEORITES ALH 83100 AND LEW 90500 USING LIQUID CHROMATOGRAPHY-TIME OF FLIGHT-MASS SPECTROMETRY
The investigation of organic compounds in primitive carbonaceous meteorites provides a record of the chemical processes that occurred in the early solar system. In particular, amino acids have been shown to be potential indicators in tracing the nature of carbonaceous chondrite parent bodies [ 13. The delivery of amino acids by carbonaceous chondrites to the early Earth could have been any important source of the Earth's prebiotic organic inventory [2]. Over 80 different amino acids have been detected in the Murchison CM2 meteorite, most of them completely non-existent in the terrestrial biosphere [3]. We have optimized a new liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) technique coupled with OPAMAC derivatization in order to detect amino acids in meteorite extracts by UV fluorescence and exact mass simultaneously. The detection limit of the LC-ToF-MS instrument for amino acids is at least 3 orders of magnitude lower than traditional GC-MS techniques. Here we report on the first analyses of amino acids and their enantiomeric abundances in the CM2 carbonaceous meteorites ALH 83100, LEW 90500, and Murchison using this new LC-ToF-MS instrument configuration. Amino acid analyses of any kind for the CM meteorite ALH 83100 have not previously been reported
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Ice damage in loblolly pine: Understanding the factors that influence susceptibility.
Abstract: Winter ice storms frequently occur in the southeastern United States and can severely damage softwood plantations. In January 2004, a severe storm deposited approximately 2 cm of ice on an intensively managed 4-year-old loblolly pine (Pinus taeda L.) plantation in South Carolina. Existing irrigation and fertilization treatments presented an opportunity to examine the effects of resource amendments on initial ice damage and subsequent recovery. Fertilized treatments showed more individual stem breakage, whereas non fertilized treatments showed more stem bending; however, the proportion of undamaged trees did not differ between treatments. Irrigation did not influence the type of damage. Trees that experienced breakage during the storm were taller with larger diameter and taper and leaf, branch, and crown biomass compared with unbroken trees. One growing season after ice damage, relative height increases were significantly greater for trees experiencing stem breakage compared with unbroken trees; however, relative diameter increases were significantly lower for these trees. Relative diameter increases for broken trees were smaller for fertilized treatments compared with nonfertilized treatments. A reduction in wood strength was ruled out as the cause of greater breakage in fertilized trees; rather, fertilized trees had reached an intermediate diameter range known to be susceptible to breakage under ice loading
Neuroinflammatory Gene Expression Alterations in Anterior Cingulate Cortical White and Gray Matter of Males With Autism Spectrum Disorder
Evidence for putative pathophysiological mechanisms of autism spectrum disorder (ASD), including peripheral inflammation, blood–brain barrier disruption, white matter alterations, and abnormal synaptic overgrowth, indicate a possible involvement of neuroinflammation in the disorder. Neuroinflammation plays a role in the development and maintenance of the dendritic spines involved in glutamatergic and GABAergic neurotransmission, and also influences blood–brain permeability. Cytokines released from microglia can impact the length, location or organization of dendritic spines on excitatory and inhibitory cells as well as recruit and impact glial cell function around the neurons. In this study, gene expression levels of anti- and pro-inflammatory signaling molecules, as well as oligodendrocyte and astrocyte marker proteins, were measured in both gray and white matter tissue in the anterior cingulate cortex from ASD and age-matched typically developing (TD) control brain donors, ranging from ages 4 to 37 years. Expression levels of the pro-inflammatory gene, HLA-DR, were significantly reduced in gray matter and expression levels of the anti-inflammatory gene MRC1 were significantly elevated in white matter from ASD donors as compared to TD donors, but neither retained statistical significance after correction for multiple comparisons. Modest trends toward differences in expression levels were also observed for the pro-inflammatory (CD68, IL1β) and anti-inflammatory genes (IGF1, IGF1R) comparing ASD donors to TD donors. The direction of gene expression changes comparing ASD to TD donors did not reveal consistent findings implicating an elevated pro- or anti-inflammatory state in ASD. However, altered expression of pro- and anti-inflammatory gene expression indicates some involvement of neuroinflammation in ASD.
Lay Summary: The anterior cingulate cortex is an integral brain region in modulating social behaviors including nonverbal communication. The study found that inflammatory gene expression levels were altered in this brain region. We hypothesize that the inflammatory changes in this area could impact neuronal function. The finding has future implications in using these molecular markers to identify potential environmental exposures and distinct cell differences in autism
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