3,088 research outputs found
Effects of temperature on the biology of the northern shrimp, Pandalus borealis, in the Gulf of Maine
Length-frequency data collected from inshore and offshore locations in the Gulf of Maine in 1966-1968 indicated that ovigerous female northern shrimp (Pandalus borealis) first appeared offshore in August and September and migrated
inshore in the fall and winter. Once eggs hatched, surviving females returned offshore. Juveniles and males migrated offshore during their first two years of life. Sex transition occurred in both inshore and oll'shore waters, but most males changed sex offshore during their third and fourth years. Most shrimp changed sex and matured as females for the first time in their fourth year. Smaller females and females exposed to colder bottom temperatures spawned first. The incidence of egg parasitism peaked in January and was higher for shrimp exposed to warmer bottom temperatures. Accelerated growth at higher temperatures appeared to result in earlier or more rapid sex transition. Males and non-ovigerous females were observed to make diurnal vertical migrations, but were not found in near-
surface waters where the temperature exceeded 6°C. Ovigerous females fed more heavily on benthic molluscs in inshore waters in the winter, presumably because the egg masses they were carrying prevented them from migrating vertically at night.
Northern shrimp were more abundant in the southwestern region of the Gulf of Maine where bottom temperatures remain low throughout the year. Bottom trawl catch rates were highest in Jeffreys Basin where bottom temperatures were lower than at any other sampling location. Catch rates throughout the study area were inversely related to bottom temperature and reached a maximum at 3°C.
An increase of 40% in fecundity between 1973 and 1979 was associated with a decline of 2-3°C in April-July offshore bottom temperatures. Furthermore, a decrease in mean fecundity per 25 mm female between 1965 and 1970 was linearly related to reduced landings between 1969 and 1974. It is hypothesized that temperature-induced changes in fecundity and, possibly, in the extent of egg mortality
due to parasitism, may provide a mechanism which could partially account for changes in the size of the Gulf of Maine northern shrimp population during the last thirty years. (PDF file contains 28 pages.
Rhapso : automatic stitching of mass segments from fourier transform ion cyclotron resonance mass spectra
Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) provides the resolution and mass accuracy needed to analyze complex mixtures such as crude oil. When mixtures contain many different components, a competitive effect within the ICR cell takes place that hampers the detection of a potentially large fraction of the components. Recently, a new data collection technique, which consists of acquiring several spectra of small mass ranges and assembling a complete spectrum afterward, enabled the observation of a record number of peaks with greater accuracy compared to broadband methods. There is a need for statistical methods to combine and preprocess segmented acquisition data. A particular challenge of quadrupole isolation is that near the window edges there is a drop in intensity, hampering the stitching of consecutive windows. We developed an algorithm called Rhapso to stitch peak lists corresponding to multiple different m/z regions from crude oil samples. Rhapso corrects potential edge effects to enable the use of smaller windows and reduce the required overlap between windows, corrects mass shifts between windows, and generates a single peak list for the full spectrum. Relative to a stitching performed manually, Rhapso increased the data processing speed and avoided potential human errors, simplifying the subsequent chemical analysis of the sample. Relative to a broadband spectrum, the stitched output showed an over 2-fold increase in assigned peaks and reduced mass error by a factor of 2. Rhapso is expected to enable routine use of this spectral stitching method for ultracomplex samples, giving a more detailed characterization of existing samples and enabling the characterization of samples that were previously too complex to analyze
Monitoring live fuel moisture using soil moisture and remote sensing proxies
Live fuel moisture (LFM) is an important fuel property controlling fuel ignition and fire propagation. LFM varies seasonally, and is controlled by precipitation, soil moisture, evapotranspiration, and plant physiology. LFM is typically sampled manually in the field, which leads to sparse measurements in space and time. Use of LFM proxies could reduce the need for field sampling while potentially improving spatial and temporal sampling density. This study compares soil moisture and remote sensing data to field-sampled LFM for Gambel oak (Quercus gambelii Nutt) and big sagebrush (Artemisia tridentata Nutt) in northern Utah. Bivariate linear regression models were constructed between LFM and four independent variables. Soil moisture was more strongly correlated with LFM than remote sensing measurements, and produced the lowest mean absolute error (MAE) in predicted LFM values at most of the sites. When sites were pooled, canopy water content (CWC) had stronger correlations with LFM than normalized difference vegetation index (NDVI) or normalized difference water index (NDWI). MAE values for all proxies were frequently above 20 % LFM at individual sites. Despite this relatively large error, remote sensing and soil moisture data may still be useful for improving understanding of spatial and temporal trends in LFM
Sevier County Agriculture Profile
This publication includes a report that gives agricultural facts and statistics pertaining to Sevier County
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Inhibition of PP2A by hesperetin may contribute to Akt and ERK1/2 activation status in cortical neurons
Flavonoids and their metabolites are well reported to modulate the activation/phosphorylation of various cellular kinases, such as ERK1/2 and JNK, although the mechanism by which they do so is unclear. In this study, we investigated the impact of flavanones on the activation of PI3K/Akt and ERK1/2 and determine whether this is mediated, in part, by the inhibition of phosphatases. Primary cortical neurons were exposed to physiological concentrations of hesperetin and the phosphorylation status of the kinases PI3K/Akt and ERK1/2 and the phosphatases PP2A and PTEN were assessed by immunoblotting after 30 min. Exposure to 100-300 nM hesperetin led to significant increases in the phosphorylation of ERK1/2 and Akt and significant decreases in PP2A levels and enzyme activity. Using in silico docking, hesperetin was found to fit into the active site of PP2A interacting within the hydrophobic cage of the catalytic unit. These data suggest a potential mechanism by which flavanones may lead to increased activation of ERK1/2 and Akt, commonly observed in cell models. Their interaction with and inhibition of cellular phosphatases counteract normal physiological regulation of signaling pathway activation thus facilitating and/or maintaining the activation status of ERK1/2 and Akt, important regulators of brain functions
Public perceptions of drinking water: A postal survey of residents with private water supplies
Background: In Canada, the legal responsibility for the condition of private water supplies,
including private wells and cisterns, rests with their owners. However, there are reports that
Canadians test these water supplies intermittently and that treatment of such water is uncommon.
An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An
understanding of the perceptions and needs of Canadians served by private water supplies is
essential, as it would enable public health professionals to better target public education and
drinking water policy. The purpose of this study was to investigate the public perceptions of private
water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public
education and outreach strategies within the population.
Methods: A cross-sectional postal survey of 246 residences with private water supplies was
conducted in May 2004. Questions pertained to the perceptions of water quality and alternative
water sources, water testing behaviours and the self-identified need for further information.
Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and
13% of respondents, respectively. Although respondents rated their water quality highly, 80% also
had concerns with its safety. The most common concerns pertained to bacterial and chemical
contamination of their water supply and its potential negative effect on health. Approximately 56%
and 61% of respondents used in-home treatment devices and bottled water within their homes,
respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared
to regular tap water. Testing of private water supplies was performed infrequently: 8% of
respondents tested at a frequency that meets current provincial guidelines. Two-thirds of
respondents wanted more information on various topics related to private water supplies. Flyers
and newspapers were the two media reported most likely to be used.
Conclusion: Although respondents rated their water quality highly, the majority had concerns
regarding the water from their private supply, and the use of bottled water and water treatment
devices was extensive. The results of this study suggest important lines of inquiry and provide
support and input for public education programs, particularly those related to private water testing,
in this population
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Potential health effects of Champagne wine consumption
Epidemiological studies have suggested an inverse correlation between red wine consumption and the incidence of cardiovascular and neurodegenerative disorders. Although white wines are generally low in polyphenol content as compared to red wines, champagne has been shown to contain relatively high amounts of phenolic acids that may exert protective cellular actions in vivo. In this study, we have investigated the potential cardioprotective and neuroprotective effects of champagne. Our data suggest that a daily moderate consumption of champagne may improve vascular performance via the delivery of phenolic constituents capable of improving NO bioavailability and the
modulation of metalloproteinase. Moreover, champagne intervention significantly increased spatial working memory in aged animals, whilst no improvement was observed in the presence of alcohol. Together, these data indicate that polyphenols present in champagne may induce cardioprotective and neuroprotective effects, delaying the onset of degenerative disorders
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