2,061 research outputs found

    Otolith Age Validation and Microchemical Investigation of the Northern Stock f Atlantic Black Sea Bass (Centropristis Striata)

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    Black sea bass (Centropristis striata) is a demersal marine species that supports extensive commercial and recreational fisheries along the Atlantic coast. A recent expansion into the Gulf of Maine raises questions about this species’ movement and population dynamics in the region. Additionally, the 2016 catch-at-age stock assessment model for the northern stock incorporated a population split at the Hudson Canyon. Though this model better accounts for differences in populations, several issues remain. First, validation of the otolith ageing technique for this stock is incomplete; and, second, the origin of fish that moved into the northern ranges of the Gulf of Maine (GOM) remains unclear. Error stemming from inaccurate age determinations can have serious effects on age-structured calculations (e.g. growth rate) leading to stock assessments that do not correctly reflect the population. In this study, I validated the black sea bass otolith ageing method using marginal increment analysis and young-of-year annulus measurements. Samples spanned the spatial distribution and age range of the northern stock. Results indicated black sea bass otoliths complete an annual increment, one translucent and one opaque band, in the late spring or early summer. Additionally, the first annulus was validated, an important step in verifying total age that is not present in the current literature for this species. The natal origin of black sea bass caught in the northern ranges of the GOM was assessed by otolith core trace element and stable isotope microchemistry. Analysis of spawning adult otoliths identified unique chemical fingerprints for the regions north and south of the Hudson Canyon: Southern New England (SNE) and the Mid-Atlantic Bight (MAB), respectively. Black sea bass caught in Maine waters were assigned to a spawning region by matching chemical fingerprints. Overall, 87% were assigned to SNE and 13% to MAB. This project helps to improve the accuracy and precision of black sea bass otolith ageing practices by validating the method used by agencies and organizations across its distribution. Additionally, this project confirms hypotheses that SNE spawned fish moved north, and further elucidates population composition of the GOM, an area where little is known about this species

    Optical Fiber-Based Sensing of Strain and Temperature at High Temperature

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    In-line intensity-based and Fabry-Perot silica optical fiber sensors have been developed to measure strain and temperature at temperatures up to 1500°F. The intensity-based sensor is an air gap splice in which the gap spacing changes as the length of the sensor housing changes. Two silica multimode optical fibers are placed in a hollow silica tube so their ends are separated by an initial gap spacing. As the sensor is strained, the gap spacing varies, resulting in a predictable change in output intensity. The Fabry-Perot sensor uses both single-mode and multimode fibers which are axially aligned inside a similar hollow core fiber. The four percent reflections which occur at both the glass-air interface at the end of the input singlemode fiber and at the air-glass interface at the surface of the multimode fiber differ in phase by an amount proportional to the separation between the two fiber ends. As the sensor is strained, the separation distance between these fiber ends changes, and the output signal intensity varies due to the interference between the reflected signals

    Evaluation of Alcohol Preference and Drinking in msP Rats Bearing a Crhr1 Promoter Polymorphism

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    Alcoholism is a pervasive societal problem, yet available pharmacotherapies fail to treat most sufferers. The type 1 corticotropin-releasing factor (CRF1) receptor has received much attention for its putative role in the progression to alcohol dependence, although at present its success in clinical trials has been limited. Two single-nucleotide polymorphisms in the rat Crhr1 promoter have been identified in the Marchigian substrain of Sardinian alcohol-preferring (msP) rats. Unlike other Wistar-derived alcohol-preferring lines, nondependent msP rats reduce their alcohol self-administration in response to CRF1 antagonists and show increased brain CRF1 expression. The current study tested the hypotheses that the A alleles in the Crhr1 promoter polymorphisms are: (1) unique to msP (vs. CRF1 antagonist-insensitive) alcohol-preferring lines and (2) associate with greater alcohol preference or intake. Two related polymorphisms were observed in which both loci on a given chromosome were either mutant variant (A) or wild-type (G) alleles within the distal Crhr1 promoter of 17/25 msP rats (68%), as compared to 0/23 Indiana P rats, 0/20 Sardinian alcohol-preferring rats bred at Scripps (Scr:sP) and 0/21 outbred Wistar rats. Alcohol consumption in msP rats did not differ according to the presence of Crhr1 A alleles, but greater alcohol preference (98%) was observed in A allele homozygous msP rats (AA) compared to msP rats with wild-type (GG, 91%) or heterozygous (GA, 91%) genotypes. The greater alcohol preference reflected decreased water intake, accompanied by reduced total calories consumed by AA rats. The data show that msP rats differentially possess mutant A variant alleles in the polymorphic promoter region of the Crhr1 gene that may differentially regulate consumption

    Amelioration of bleomycin-induced lung fibrosis in hamsters by dietary supplementation with taurine and niacin: biochemical mechanisms.

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    Interstitial pulmonary fibrosis induced by intratracheal instillation of bleomycin (BL) involves an excess production of reactive oxygen species, unavailability of adequate levels of NAD and ATP to repair the injured pulmonary epithelium, and an overexuberant lung collagen reactivity followed by deposition of highly cross-linked mature collagen fibrils resistant to enzymatic degradation. In the present study, we have demonstrated that dietary supplementation with taurine and niacin offered almost complete protection against the lung fibrosis in a multidose BL hamster model. The mechanisms for the protective effect of taurine and niacin are multifaceted. These include the ability of taurine to scavenge HOCl and stabilize the biomembrane; niacin's ability to replenish the BL-induced depletion of NAD and ATP; and the combined effect of taurine and niacin to suppress all aspects of BL-induced increases in the lung collagen reactivity, a hallmark of interstitial pulmonary fibrosis. It was concluded from the data presented at this Conference that the combined treatment with taurine and niacin, which offers a multipronged approach, will have great therapeutic potential in the intervention of the development of chemically induced interstitial lung fibrosis in animals and humans

    Human Urocortin 2, a Corticotropin-Releasing Factor (CRF) 2

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    Assessing Internet addiction using the parsimonious Internet addiction components model - a preliminary study [forthcoming]

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    Internet usage has grown exponentially over the last decade. Research indicates that excessive Internet use can lead to symptoms associated with addiction. To date, assessment of potential Internet addiction has varied regarding populations studied and instruments used, making reliable prevalence estimations difficult. To overcome the present problems a preliminary study was conducted testing a parsimonious Internet addiction components model based on Griffiths’ addiction components (2005), including salience, mood modification, tolerance, withdrawal, conflict, and relapse. Two validated measures of Internet addiction were used (Compulsive Internet Use Scale [CIUS], Meerkerk et al., 2009, and Assessment for Internet and Computer Game Addiction Scale [AICA-S], Beutel et al., 2010) in two independent samples (ns = 3,105 and 2,257). The fit of the model was analysed using Confirmatory Factor Analysis. Results indicate that the Internet addiction components model fits the data in both samples well. The two sample/two instrument approach provides converging evidence concerning the degree to which the components model can organize the self-reported behavioural components of Internet addiction. Recommendations for future research include a more detailed assessment of tolerance as addiction component

    Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton

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    Members of the mammalian family Felidae (extant and extinct cats) are grossly phenotypically similar, but display a 300-fold range in body size, from less than 1 kg to more than 300 kg. In addition to differences in body mass, felid species show dietary and locomotory specializations that correlate to skull and limb osteological measurements, such as shape or cross-sectional area. However, ecological correlates to the axial skeleton are yet untested. Here, we build on previous studies of the biomechanical and morphological evolution of the felid appendicular skeleton by conducting a quantitative analysis of morphology and allometry in the presacral vertebral column across extant cats. Our results demonstrate that vertebral columns of arboreal, scansorial and terrestrial felids significantly differ in morphology, specifically in the lumbar region, while no distinction based on dietary specialization was found. Body size significantly influences vertebral morphology, with clear regionalization of allometry along the vertebral column, suggesting that anterior (cervicals and thoracics) and posterior (lumbar) vertebrae may be independently subjected to distinct selection pressures

    The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles

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    The body masses of cats (Mammalia, Carnivora, Felidae) span a ~300‐fold range from the smallest to largest species. Despite this range, felid musculoskeletal anatomy remains remarkably conservative, including the maintenance of a crouched limb posture at unusually large sizes. The forelimbs in felids are important for body support and other aspects of locomotion, as well as climbing and prey capture, with the assistance of the vertebral (and hindlimb) muscles. Here, we examine the scaling of the anterior postcranial musculature across felids to assess scaling patterns between different species spanning the range of felid body sizes. The muscle architecture (lengths and masses of the muscle‐tendon unit components) for the forelimb, cervical and thoracic muscles was quantified to analyse how the muscles scale with body mass. Our results demonstrate that physiological cross‐sectional areas of the forelimb muscles scale positively with increasing body mass (i.e. becoming relatively larger). Many significantly allometric variables pertain to shoulder support, whereas the rest of the limb muscles become relatively weaker in larger felid species. However, when phylogenetic relationships were corrected for, most of these significant relationships disappeared, leaving no significantly allometric muscle metrics. The majority of cervical and thoracic muscle metrics are not significantly allometric, despite there being many allometric skeletal elements in these regions. When forelimb muscle data were considered in isolation or in combination with those of the vertebral muscles in principal components analyses and MANOVAs, there was no significant discrimination among species by either size or locomotory mode. Our results support the inference that larger felid species have relatively weaker anterior postcranial musculature compared with smaller species, due to an absence of significant positive allometry of forelimb or vertebral muscle architecture. This difference in strength is consistent with behavioural changes in larger felids, such as a reduction of maximal speed and other aspects of locomotor abilities
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