1,122 research outputs found
Tracking environmental trends in the Great Bay Estuarine System: An examination of water quality and nuisance macroalgal blooms
Monitoring macroalgae populations is an effective means of detecting long term water quality changes in estuarine systems. To investigate the environmental status of New Hampshire\u27s Great Bay National Estuarine Research Reserve, this study assessed the abundance/distribution of macrophytes, particularly Gracilaria and Ulva species, relative to eutrophication patterns; compared historical (1970s-1990s) and current algal biomass/cover at several sites; and compared Ulva and Gracilaria tissue N/P content to ambient and historical levels. Nitrogen and phosphorus testing revealed that the estuarine system has become eutrophic, and Ulva and Gracilaria biomass/cover have increased significantly. The percent cover of Ulva species, at seasonal maxima, was over 90 times the value recorded in the 1970s at Lubberland Creek, and exceeded 50% cover at all sites in the upper estuary. Gracilaria cover was greater than 25% at Depot Road in the upper estuary, whereas the historical measure was 1%. Sequencing of ITS2, rbcL, and CO1 revealed the presence of previously undetected Ulva and Gracilaria species, including Gracilaria vermiculophylla (Ohmi) Papenfuss, an invasive species of Asian origin. Gracilaria vermiculophylla has surpassed G. tikvahiae as the dominant Gracilaria species in the Great Bay Estuarine System.
Field collections, evaluations of historical herbarium specimens, and molecular investigations (including CO1 gene sequencing) of Gracilaria vermiculophylla were used to document its present distribution and approximate dates of introduction within New England. It was found at 18 of 24 Northwest Atlantic sites with existing native Gracilaria tikvahiae populations. Presently G. vermiculophylla is recorded from Stamford, CT to Greenland, NH. Molecular screening of historical herbarium specimens revealed that G. vermiculophylla was collected from five sites in Massachusetts during 2000, while it was first collected in the middle of the Great Bay Estuarine System (Dover Point, NH) during 2003. In Rhode Island, initial specimens were documented during 2007, while those in Connecticut were first confirmed during 2010. As G. vermiculophylla has gone primarily undetected in New England since at least 2000, this highlights the difficulty of documenting the arrival and spread of an invasive species that closely resembles a native congener. Hence, DNA sequencing is critical to clarifying the introduction and expansion of such non-native seaweeds
Tracking environmental trends in the Great Bay Estuarine System through comparisons of historical and present-day green and red algal community structure and nutrient content
Monitoring macroalgae populations is an effective means of detecting long term water quality changes in estuarine systems. To investigate the environmental status of New Hampshireâs Great Bay National Estuarine Research Reserve, this study assessed the abundance/distribution of macrophytes, particularly Gracilaria and Ulva species, relative to eutrophication patterns; compared historical (1970s-1990s) and current algal biomass/cover at several sites; and compared Ulva and Gracilaria tissue N/P content to ambient and historical levels. Ulva and Gracilaria biomass/cover have increased significantly at several sites. Cover by Ulva species, at seasonal maxima, was over 90 times the value recorded in the 1970s at Lubberland Creek, and exceeded 50% at all sites in the upper estuary. Gracilaria cover was greater than 25% at Depot Road in the upper estuary, whereas the historical measure was 1%. Sequencing of ITS2, rbcL and CO1 revealed the presence of previously undetected Ulva and Gracilaria species, including Gracilaria vermiculophylla (Ohmi) Papenfuss, an invasive species of Asian origin. Gracilaria vermiculophylla has exceeded G. tikvahiae as the dominant Gracilaria species in Great Bay. Historical voucher specimen screening suggests G. vermiculophylla was introduced as recently as 2003. Nitrogen and phosphorus levels are elevated in the estuary. We should expect continued seasonal nuisance algal blooms
Ecology, distribution, quantification, and impact of introduced, Asian Porphyra yezoensis f yezoensis Ueda and Porphyra yezoensis f narawaensis A Miura in the Northwestern Atlantic
Invasive species pose a threat to the balance of intertidal ecosystems. Recently, two forms of the non-native species, Porphyra yezoensis Ueda, were found at multiple sites between New York and Downcast Maine. A 2007 New England survey confirmed the presence of P. yezoensis f. yezoensis at nine sites, including two beyond its reported distribution. Porphyra yezoensis f narawaensis A. Miura was found at four sites in Long Island Sound. To assess the ecological impact of f. yezoensis and f. narawaensis on Northwest Atlantic macroalgal communities, monthly density and biomass data were gathered in 2008 from seven southern New England sites along 20 m transect lines. P. yezoensis f. yezoensis was not detected at two historic sites. The f. narawaensis has expanded to Cape Cod. Fucoid algae epiphytized by P. yezoensis demonstrated no stature reduction. A Porphyra species of cryptic origins, P. spp. \u27stamfordensis,\u27 may be competing with P. yezoensis
Test of Information Theory on the Boltzmann Equation
We examine information theory using the steady-state Boltzmann equation. In a
nonequilibrium steady-state system under steady heat conduction, the
thermodynamic quantities from information theory are calculated and compared
with those from the steady-state Boltzmann equation. We have found that
information theory is inconsistent with the steady-state Boltzmann equation.Comment: 12 page
The Structure of Urinary Catheter Encrusting Bacterial Biofilms
A major complication of long-term urethral catheterization is catheter blockage by encrustation. We have examined 20 encrusted catheters and in each case crystal formation was associated with the presence of bacterial biofilms on the luminal surfaces. Scanning electron microscopy and X-ray microanalysis indicated the presence of struvite and hydroxyapatite in the biofilms. Urease producing bacteria were colonizing 16 of the catheters. Proteus mirabilis was the commonest species being recovered from ten of the catheters. These results support the hypothesis that catheter encrustation has a similar etiology to that of infection-induced urinary stones and confirm that the important target for any attempt to control catheter encrustations is Pr. mirabilis
Shock tunnel studies of scramjet phenomena, supplement 6
Reports by the staff of the University of Queensland on various research studies related to the advancement of scramjet technology are presented. These reports document the tests conducted in the reflected shock tunnel T4 and supporting research facilities that have been used to study the injection, mixing, and combustion of hydrogen fuel in generic scramjets at flow conditions typical of hypersonic flight. In addition, topics include the development of instrumentation and measurement technology, such as combustor wall shear and stream composition in pulse facilities, and numerical studies and analyses of the scramjet combustor process and the test facility operation
Gene expression profiling of the short-term adaptive response to acute caloric restriction in liver and adipose tissues of pigs differing in feed efficiency
Residual feed intake (RFI) is a measure of feed efficiency, in which low RFI denotes improved feed efficiency. Caloric restriction (CR) is associated with feed efficiency in livestock species and to human health benefits, such as longevity and cancer prevention. We have developed pig lines that differ in RFI, and we are interested in identifying the genes and pathways that underlie feed efficiency. Prepubertal Yorkshire gilts with low RFI (n = 10) or high RFI (n = 10) were fed ad libitum or fed at restricted intake of 80% of maintenance energy requirements for 8 days. We measured serum metabolites and hormones and generated transcriptional profiles of liver and subcutaneous adipose tissue on these animals. Overall, 6,114 genes in fat and 305 genes in liver were differentially expressed (DE) in response to CR, and 311 genes in fat and 147 genes in liver were DE due to RFI differences. Pathway analyses of CR-induced DE genes indicated a dramatic switch to a conservation mode of energy usage by down-regulating lipogenesis and steroidogenesis in both liver and fat. Interestingly, CR altered expression of genes in immune and cell cycle/apoptotic pathways in fat, which may explain part of the CR-driven lifespan enhancement. In silico analysis of transcription factors revealed ESR1 as a putative regulator of the adaptive response to CR, as several targets of ESR1 in our DE fat genes were annotated as cell cycle/apoptosis genes. The lipid metabolic pathway was overrepresented by down-regulated genes due to both CR and low RFI. We propose a common energy conservation mechanism, which may be controlled by PPARA, PPARG, and/or CREB in both CR and feed-efficient pigs
Some thoughts about nonequilibrium temperature
The main objective of this paper is to show that, within the present
framework of the kinetic theoretical approach to irreversible thermodynamics,
there is no evidence that provides a basis to modify the ordinary Fourier
equation relating the heat flux in a non-equilibrium steady state to the
gradient of the local equilibrium temperature. This fact is supported, among
other arguments, through the kinetic foundations of generalized hydrodynamics.
Some attempts have been recently proposed asserting that, in the presence of
non-linearities of the state variables, such a temperature should be replaced
by the non-equilibrium temperature as defined in Extended Irreversible
Thermodynamics. In the approximations used for such a temperature there is so
far no evidence that sustains this proposal.Comment: 13 pages, TeX, no figures, to appear in Mol. Phy
Prevention of Mycobacterium avium Subspecies paratuberculosis (MAP) Infection in Balb/c mice by Feeding Lactobacillus acidophilus Strain NP-51Âź
The immune responses of 390 BALB/c mice fed the probiotic Lactobacillus acidophilus strain NP51 Âź and infected with Mycobacterium avium subspecies paratuberculosis (MAP) were evaluated in a 6-month trial. Mice were randomized to nine treatment groups that fed either viable- or heat-killed NP51 and inoculated with either viable- or heatkilled MAP or sterile phosphate-buffered saline. Feeding the NP51 resulted in higher numbers of T lymphocytes in the spleen including the CD8 + cytotoxic T lymphocytes. In addition, feeding the NP51 lowered the number of immune suppressive T regulatory cells CD4 + CD25 + and CD8 + CD25 + cells in the spleen. Additionally, feeding the NP51 resulted in higher concentration of interferon-gamma in the supernatant of splenocytes cultured in vitro. These results suggest that feeding the NP51 to BALB/c mice might prevent the progression of MAP infection in mice
Nonequilibrium corrections in the pressure tensor due to an energy flux
The physical interpretation of the nonequilibrium corrections in the pressure
tensor for radiation submitted to an energy flux obtained in some previous
works is revisited. Such pressure tensor is shown to describe a moving
equilibrium system but not a real nonequilibrium situation.Comment: 4 pages, REVTeX, Brief Report to appear in PRE Dec 9
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