1,281 research outputs found
Alligator Diet in Relation to Alligator Mortality on Lake Griffin, FL
Alligator mississippiensis (American Alligators) demonstrated low hatchrate
success and increased adult mortality on Lake Griffin, FL, between 1998 and
2003. Dying Lake Griffin alligators with symptoms of poor motor coordination were
reported to show specific neurological impairment and brain lesions. Similar lesions
were documented in salmonines that consumed clupeids with high thiaminase levels.
Therefore, we investigated the diet of Lake Griffin alligators and compared it with
alligator diets from two lakes that exhibited relatively low levels of unexplained
alligator mortality to see if consumption of Dorosoma cepedianum (gizzard shad)
could be correlated with patterns of mortality. Shad in both lakes Griffin and Apopka
had high levels of thiaminase and Lake Apopka alligators were consuming greater
amounts of shad relative to Lake Griffin without showing mortality rates similar to
Lake Griffin alligators. Therefore, a relationship between shad consumption alone
and alligator mortality is not supported
Beyond Marine Reserves: Exploring the Approach of Selecting Areas where Fishing Is Permitted, Rather than Prohibited
Background:\ud
Marine populations have been declining at a worrying rate, due in large part to fishing pressures. The challenge is to secure a future for marine life while minimizing impacts on fishers and fishing communities.\ud
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Methods and Principal Findings:\ud
Rather than selecting areas where fishing is banned – as is usually the case with spatial management – we assess the concept of designating areas where fishing is permitted. We use spatial catch statistics for thirteen commercial fisheries on Canada’s west coast to determine the minimum area that would be needed to maintain a pre-ascribed target percentage of current catches. We found that small reductions in fisheries yields, if strategically allocated, could result in large unfished areas that are representative of biophysical regions and habitat types, and have the potential to achieve remarkable conservation gains.\ud
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Conclusions:\ud
Our approach of selecting fishing areas instead of reserves could help redirect debate about the relative values that society places on conservation and extraction, in a framework that could gain much by losing little. Our ideas are intended to promote discussions about the current status quo in fisheries management, rather than providing a definitive solution
A URANIUM ATLAS IN ASCII FORMAT, 20000 - 27000 cm−1
This work was motivated by difficulties encountered while trying to calibrate laser excitation spectra, taken in short (1 {cm}) scans around
438 nm, by matching optogalvanic transitions from a Uranium-Argon hollow cathode lamp to peaks listed in a widely circulated `informal report' on the Uranium spectrum
(11000~--25900 {cm}) from Los Alamos, published in 1980\footnote{An atlas of uranium emission intensities in a hollow cathode discharge; Palmer, Keller \& Engleman, Los Alamos report LA 8251-MS, (1980)}. Short pieces of excitation spectra often fell between secure calibration lines, because many of the
weaker features had been excluded from the printed linelist. To remedy this, we have re-recorded emission from a commercial Uranium hollow-cathode lamp
19800~--~27400 {cm} on a Fourier transform spectrometer, at an instrumental resolution of at 0.04 {cm}. The wavenumber scale was fine-tuned to match earlier reference data\footnote{Comparing the emission spectra of U and Th hollow cathode lamps, and a new U line list; Sarmiento , A \& A, \underline{618}, A118, (2018)}\footnote{Uranium and iodine standards measured by means of Fourier-transform spectroscopy; Gerstenkorn, , A \& A, \underline{58}, 255-66, (1977)} to within 0.003 {cm}. This spectrum (together with its peak list) is proposed in ascii format\footnote{A uranium atlas, from 365 to 505 nm; Ross J Mol Spectrosc (accepted) 2020} as a possible aid to calibration of laser excitation spectra in the blue, violet and near UV. It extends the spectrum reported by Sarmiento and co-workers that focused on calibration of astronomical spectrographs in the near IR and visible
PROBING THE ZEEMAN EFFECT IN LOW-Ω F4∆← X 4∆ TRANSITIONS IN FeH
This work targets laboratory studies of the Zeeman effects in selected transitions of the FeH radical, observed in the atmospheres of dwarf stars.
The \emph{F}\emph{X} electronic system falls around 1 m, and matches observation windows of the high-resolution spectropolarimeters
SPIRou (brought into service in 2019) and ESPaDOnS mounted at the Canada-France-Hawaii Telescope. Many field-free line positions have already been reported for this radical from laboratory studies, notably from high-temperature sources\footnote{Line intensities and molecular opacities of the FeH \emph{F}^4\Delta_{i}\leftarrow \emph{X}~^4\Delta_i transition; Dulick ; Astrophys. J., \underline{594}, 651-63, (2003)}\footnote{The near-Infrared Spectrum of the FeH Molecule; Phillips ; Astrophys. J. Supp. Ser., 65, 721-78, (1987)}.
Our earlier work with a sputter source\footnote{Determination of Land\'e factors in the state of FeH by laser excitation spectroscopy; Crozet ; J. Mol. Spectrosc., \underline{303}, 46-53, (2014)} yielded information on magnetic response for just a few transitions between the two lowest spin components of the and states.
We report here some preliminary results obtained from FeH formed in reaction between hydrogen atoms (generated in a microwave discharge of H in argon) and traces of iron pentacarbonyl vapour, at pressures around 1 Torr. This source\footnote{Detection of the free radicals FeH, CoH and NiH by far IR laser magnetic resonance; Beaton ; J. Chem. Phys. \underline{89}, 4446-48, (1988)} seems to produce more population in the \emph{X}~^4\Delta_{3/2} and \emph{X}~^4\Delta_{1/2} components of the ground state. Laser excitation of [1-0] transitions, with lock-in detection of fluorescence in the [1-1] band to eliminate laser scatter, has allowed some Zeeman-broadened profiles to be measured
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Up and away: ontogenic transference as a pathway for aerial dispersal of microplastics
Microplastics (MPs) are ubiquitous pollutants found in marine, freshwater and terrestrial ecosystems. With so many MPs in aquatic systems it is inevitable that they will be ingested by aquatic organisms, and be transferred up through the food chain. However, to date, no study has considered whether MPs can be transmitted by means of ontogenic transference i.e. between life stages that utilise different habitats. Here, we determine whether fluorescent polystyrene beads could transfer between Culex mosquito life stages and, particularly, could move into the flying adult stage. We show for the first time that MPs can be transferred ontogenically from a feeding (larva) into a non-feeding (pupa) life stage and subsequently into the adult terrestrial life stage. However, transference is dependent on particle size, with smaller 2 µm MPs transferring readily into pupae and adult stages, whilst 15 µm MPs transferred at a significantly reduced rate. Microplastics appear to accumulate in the Malpighian tubule renal excretion system. The transfer of MPs to the adults represents a potential aerial pathway to contamination of new environments. Thus, any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems
Ex-vivo perfusion bioassay : an excellent technique to measure the bioactivity of inhalable insulin coated microcrystals
Purpose: To measure the bioactivity of inhalable insulin coated microcrystals using a perfusion bioassay that measures its vasodilatory effect on smooth muscle arterial tissue. Methods: The bioactivity of an insulin protein coated microcrystal (PCMC), a potential candidate for pulmonary drug delivery and commercial insulin was determined on a Danish Myo Tech P110 pressure myograph system. 12 week old Mesenteric resistance arteries from Male Wistar rats were isolated and immersed in a physiological salt solution (PSS) and attached to 2 opposing hollow glass micro-cannula (outer diameter 80 microns). The PSS was gradually warmed to 37°C (at a pressure less than 5mm Hg) for 1hr. Subsequently the pressure was increased up to 40mm Hg over a period 15 minutes and equilibrated for a further 15 minutes after gassing with 95%O2 / 5%CO2 to achieve a pH of 7.4 at 37°C. After normalisation by two washes of 123mM KCl and exposure to 1-10mM noradrenaline the arteries were exposed intraluminally to each insulin preparation by gradual infusion directly into the lumen via a fetal microcannulae inserted to the tip of the glass mounting cannula, at a constant pressure. Results: The preliminary results (full cummulative response curve yet to be determined) demonstrate insulin mediated relaxation to noradrenaline preconstriction. The level of constriction drops from 100% to 42% as the concentration of insulin increases from -11 to -9 Log M for the PCMC compared with a drop from 100 % to 65% for the commercial insulin preparation. However the more potent vasodilatory effect found for the insulin PCMC is more likely to be a result of variance introduced in each dilution step than a real increase in potency. Conclusion: The perfusion bioassay technique provides an excellent method of measuring insulin bioactivity and indicates the insulin loaded on the microcrystal support is fully active
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Elevated plasma levels of TIMP-3 are associated with a higher risk of acute respiratory distress syndrome and death following severe isolated traumatic brain injury.
BackgroundComplications after injury, such as acute respiratory distress syndrome (ARDS), are common after traumatic brain injury (TBI) and associated with poor clinical outcomes. The mechanisms driving non-neurologic organ dysfunction after TBI are not well understood. Tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) is a regulator of matrix metalloproteinase activity, inflammation, and vascular permeability, and hence has plausibility as a biomarker for the systemic response to TBI.MethodsIn a retrospective study of 182 patients with severe isolated TBI, we measured TIMP-3 in plasma obtained on emergency department arrival. We used non-parametric tests and logistic regression analyses to test the association of TIMP-3 with the incidence of ARDS within 8 days of admission and in-hospital mortality.ResultsTIMP-3 was significantly higher among subjects who developed ARDS compared with those who did not (median 2810 pg/mL vs. 2260 pg/mL, p=0.008), and significantly higher among subjects who died than among those who survived to discharge (median 2960 pg/mL vs. 2080 pg/mL, p<0.001). In an unadjusted logistic regression model, for each SD increase in plasma TIMP-3, the odds of ARDS increased significantly, OR 1.5 (95% CI 1.1 to 2.1). This association was only attenuated in multivariate models, OR 1.4 (95% CI 1.0 to 2.0). In an unadjusted logistic regression model, for each SD increase in plasma TIMP-3, the odds of death increased significantly, OR 1.7 (95% CI 1.2 to 2.3). The magnitude of this association was greater in a multivariate model adjusted for markers of injury severity, OR 1.9 (95% CI 1.2 to 2.8).DiscussionTIMP-3 may play an important role in the biology of the systemic response to brain injury in humans. Along with clinical and demographic data, early measurements of plasma biomarkers such as TIMP-3 may help identify patients at higher risk of ARDS and death after severe isolated TBI.Level of evidenceIII
Prevalence and causes of prescribing errors: the prescribing outcomes for trainee doctors engaged in clinical training (PROTECT) study
Objectives
Study objectives were to investigate the prevalence and causes of prescribing errors amongst foundation doctors (i.e. junior doctors in their first (F1) or second (F2) year of post-graduate training), describe their knowledge and experience of prescribing errors, and explore their self-efficacy (i.e. confidence) in prescribing.
Method
A three-part mixed-methods design was used, comprising: prospective observational study; semi-structured interviews and cross-sectional survey. All doctors prescribing in eight purposively selected hospitals in Scotland participated. All foundation doctors throughout Scotland participated in the survey. The number of prescribing errors per patient, doctor, ward and hospital, perceived causes of errors and a measure of doctors' self-efficacy were established.
Results
4710 patient charts and 44,726 prescribed medicines were reviewed. There were 3364 errors, affecting 1700 (36.1%) charts (overall error rate: 7.5%; F1:7.4%; F2:8.6%; consultants:6.3%). Higher error rates were associated with : teaching hospitals (p<0.001), surgical (p = <0.001) or mixed wards (0.008) rather thanmedical ward, higher patient turnover wards (p<0.001), a greater number of prescribed medicines (p<0.001) and the months December and June (p<0.001). One hundred errors were discussed in 40 interviews. Error causation was multi-factorial; work environment and team factors were particularly noted. Of 548 completed questionnaires (national response rate of 35.4%), 508 (92.7% of respondents) reported errors, most of which (328 (64.6%) did not reach the patient. Pressure from other staff, workload and interruptions were cited as the main causes of errors. Foundation year 2 doctors reported greater confidence than year 1 doctors in deciding the most appropriate medication regimen.
Conclusions
Prescribing errors are frequent and of complex causation. Foundation doctors made more errors than other doctors, but undertook the majority of prescribing, making them a key target for intervention. Contributing causes included work environment, team, task, individual and patient factors. Further work is needed to develop and assess interventions that address these.</p
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Calanoid copepods: an overlooked tool in the control of disease vector mosquitoes
Biological control can assist in the management of disease vector mosquitoes. However, we urgently require the identification of novel and effective agents to aid population management strategies. Quantifying interactions strengths between consumers and resources is central to our understanding of trophic stability, and is relevant within the biological control context. Previously, pPredatory biocontrol of disease vector mosquito species has previously focused extensively on cyclopoid copepods, but prey size refuge effects have been identified as a hindrance to their predatory efficacy. Calanoid copepods have yet to be comprehensively examined in the context of mosquito control, despite their high prevalence, diversity and distribution. Here, we apply functional responses (FRs; resource use as a function of resource density) to examine interaction strengthspredation efficiencies of a recently described ephemeral pond specialist species, the freshwater calanoid copepod Lovenula raynerae Suárez-Morales, Wasserman & Dalu 2015, using different size classes of larvae of the disease vector complex Culex pipiens as prey. Lovenula raynerae effectively consumed C. pipiens larvae across their ontogeny. A potentially population destabilising Type II FR was exhibited towards both early and late instar mosquitoes, indicative of a lack of prey refuge across ontogenetic stages. Attack rates were greatest and handling times lowest for early instar larvae compared to late instar larvae. These traits contrast to other copepods, commonly applied in biocontrol, which are only able to handle early instars, and in much smaller numbers. We thus advocate that calanoid copepods can exert particularly marked predatory impact on lower trophic groups, and that their use in disease vector mosquito control strategies should be further explored
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Assessing multiple predator, diurnal and search area effects on predatory impacts by ephemeral wetland specialist copepods
Predator-prey interaction strengths can be highly context-dependent. In particular, multiple predator effects (MPEs), variations in predator sex and physical habitat characteristics may affect prey consumption rates and thus the persistence of lower trophic groups. Ephemeral wetlands are transient ecosystems and predatory copepods are often numerically dominant. We examine the interaction strengths of a specialist copepod Paradiaptomus lamellatus towards mosquito prey in the presence of conspecifics using a functional response (FR) approach. Further, we examine sex variability in predation rates of P. lamellatus under circadian and surface area variations. Then, we assess the influence of a co-occurring heterospecific predatory copepod, Lovernula raynerae, on total predation rates. We demonstrate MPEs affecting consumption, with negative non-trophic interaction strength and thus antagonism displayed between conspecific predatory units of P. lamellatus. This antagonism was present irrespective of prey density. Furthermore, we show differences between sexes in interaction strengths, with female P. lamellatus significantly more voracious than males, irrespective of time of day and experimental arena surface area. Predation rates by P. lamellatus were significantly lower than the heterospecific calanoid copepod L. raynerae, whilst heterospecific copepod groups exhibited the greatest predatory impact. Our results provide insights into the predation dynamics by specialist copepods, wherein species diversity and sex affect interaction strengths. In turn, this may influence population-level persistence of lower trophic groups under shifting copepod predator composition
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