Predators on marine fish farms in Tasmania

Marine aquaculture of the salmonids atlantic salmon (Salrno salar) and rainbow trout (Salmo gairdneri) is a rapidly growing industry in Tasmania. There is considerable damage to the fish on these farms by avian and mammalian predators. The mode by which these predators attack the fish on the farms allows for practical methods to reduce the loss of fish. Physically excluding predators from the fish is ultimately the only way to prevent this loss entirely. A total of six predators that interact with the farms are described and the necessity for the protection methods to be incorporated into the design of the farms prior to farm development is emphasised

Bathymetric terrain model of the Atlantic margin for marine geological investigations.

Bathymetric terrain models of seafloor morphology are an important component of marine geological investigations. Advances in acquisition and processing technologies of bathymetric data have facilitated the creation of high-resolution bathymetric surfaces that approach the resolution of similar surfaces available for onshore investigations. These bathymetric terrain models provide a detailed representation of the Earth’s subaqueous surface and, when combined with other geophysical and geological datasets, allow for interpretation of modern and ancient geological processes. The purpose of the bathymetric terrain model presented in this report is to provide a high-quality bathymetric surface of the Atlantic margin of the United States that can be used to augment current and future marine geological investigations. The input data for this bathymetric terrain model, covering almost 305,000 square kilometers, were acquired by several sources, including the U.S. Geological Survey, the National Oceanic and Atmospheric Administration National Geophysical Data Center and the Ocean Exploration Program, the University of New Hampshire, and the Woods Hole Oceanographic Institution. These data have been edited using hydrographic data processing software to maximize the quality, usability, and cartographic presentation of the combined terrain model

Optical Properties of AgCl, AgBr, T1C1, and T1Br under Hydrostatic Pressure

The pressure shifts of the optical absorption edges in four thallium and silver halides at 10°K were determined to be, in units of 10−6 eV/atm, -1.5 (AgCl), -1.9 (AgBr), -18 (TlCl), and -16 (TlBr). The pressure shifts of the first exciton peaks in thin evaporated films of these salts were measured at 80°K. In the same units these are 6.2 (AgCl), 6.4 and 5.6 (AgBr doublet), -13.9 (TlCl), and -13.4 (TlBr). The similarity of the pressure coefficients of the absorption edge in the two silver halides is evidence that the same indirect transition is responsible for the edge in both salts, presumably L3′→Γ1. The deformation potentials for the first direct exciton in the silver halides are approximately the same as those for the corresponding transitions in KBr and KI. The similarity of the pressure coefficients of the absorption edge and exciton peaks in the thallium salts is evidence that the absorption edge in these salts is the tail of the first direct exciton peak. The anomalous red shift upon cooling of the absorption edge and exciton peak in the thallium halides is shown to be the effect of thermal contraction

Photochemical Conversion of F Centers to M Centers in KCl, KBr, and CsBr

The mechanism for the formation of M centers from F centers upon irradiation in the F band is discussed. The evidence favoring F2+ (or M+) centers as intermediate states is shown to be less convincing than formerly believed. Measurements of the activation energy of the reaction rate have been made for F-to-M photoconversion in additively colored KCl (0.35 eV), KBr (0.39 eV), and CsBr (∼0.1 eV). The activation volumes for F-to-M conversion in KCl and CsBr have been measured. They are much smaller than those estimated for free anion diffusion. The same mechanism for F-to-M conversion seems to obtain in these three salts

Luminescence of F Centers in Alkali Halides under Hydrostatic Pressure

F-center luminescence spectra have been measured at 78°K in NaCl, KCl, KBr, KI, RbCl, and CsBr under hydrostatic pressure to 3.5 kbar. From a comparison between the shift of the emission peak with pressure and the shift with temperature, it is concluded that most of the latter arises from the electron-lattice interaction and not from thermal expansion. This is the opposite of the conclusion for F-center absorption, for which thermal expansion dominates the temperature coefficient of the peak energy. The halfwidth of the function W(E), the probability per unit time of emitting a photon with energy between E and E+dE, does not vary with pressure in NaCl, KCl, and RbCl, but the half-width of the shape function, E−3W(E), changes with pressure. This is interpreted as meaning that for F-center emission, it is more suitable to make the Condon approximation on the momentum operator than on the position operator. Lifetime measurements in KCl under pressure at 15 and 78°K give the pressure derivative of the thermal ionozation energy of the relaxed excited state of the F center in KCl, + 19×10−6 eV bar−1. The pressure coefficients of a few K- and L-band peaks have been determined. These provide additional evidence that the final states in the L-band transitions are not similar to those for F- and K-band transitions. The K band in RbCl changes shape with pressure. The FA-band splitting has been found to increase with pressure in KCl:Na. The F-center emission in KBr under pressure has been found to have two components, and the excitation spectrum has two peaks, the F band and a peak very close to the K′band previously found in absorption at much higher pressures. Emission data at 12°K on diverse samples of additively colored KBr strongly suggest that there are two components to the normal F-center luminescence in KBr with no applied pressure

Developmental differences in the control of action selection by social information

Our everyday actions are often performed in the context of a social interaction. We previously showed that, in adults, selecting an action on the basis of either social or symbolic cues was associated with activations in the fronto-parietal cognitive control network, whereas the presence and use of social versus symbolic cues was in addition associated with activations in the temporal and medial prefrontal cortex (MPFC) social brain network. Here we investigated developmental changes in these two networks. Fourteen adults (21–30 years of age) and 14 adolescents (11–16 years) followed instructions to move objects in a set of shelves. Interpretation of the instructions was conditional on the point of view of a visible “director” or the meaning of a symbolic cue (Director Present vs. Director Absent) and the number of potential referent objects in the shelves (3-object vs. 1-object). 3-object trials elicited increased fronto-parietal and temporal activations, with greater left lateral prefrontal cortex and parietal activations in adults than adolescents. Social versus symbolic information led to activations in superior dorsal MPFC, precuneus, and along the superior/middle temporal sulci. Both dorsal MPFC and left temporal clusters exhibited a Director × Object interaction, with greater activation when participants needed to consider the directors' viewpoints. This effect differed with age in dorsal MPFC. Adolescents showed greater activation whenever social information was present, whereas adults showed greater activation only when the directors' viewpoints were relevant to task performance. This study thus shows developmental differences in domain-general and domain-specific PFC activations associated with action selection in a social interaction context

Attenuated Cerebral Vasodilatory Capacity in Response to Hypercapnia in Young Obese Individuals

Obese individuals are at a greater risk for the development of a variety of cardio and cerebral vascular diseases including hypertension, atherosclerosis, coronary artery disease and stroke. Furthermore, obesity is associated with cognitive impairment and is a risk factor for dementia and Alzheimer’s disease. The exact mechanisms of this elevated risk are not fully characterized; however, impaired microvascular function is believed to be a contributor. This study tested the hypothesis that the cerebral vasodilatory capacity in response to hypercapnia is reduced in obese individuals relative to age and sex matched lean counterparts. Cerebral blood velocity (CBFV) was measured using transcranial Doppler before and during rebreathing-induced hypercapnia in obese (Obese, n=14) and lean (Lean, n=14) subjects. Cerebral vascular conductance (CVCI) was calculated as CBFV / mean arterial pressure (MAP), and a four parameter logistic regression was applied for sigmoidal curve fitting of the relationship between % change in CVCI and end-tidal CO2 tension (PETCO2). The magnitude of hypercapnia (Δ PETCO2) during rebreathing was similar between groups (Obese 14 ± 3 mmHg vs. Lean: 15 ± 2 mmHg; P = 0.13). The maximum increase in CVCI (Obese: 155 ± 17% vs. Lean: 176 ± 23%; P \u3c 0.05) and the total range of change in CVCI (Obese: 50 ± 15% vs. Lean: 75 ± 22%; P \u3c 0.01) during rebreathing were reduced in the obese relative to the lean individuals. These data indicate that cerebral vasodilatory capacity in response to changes in PETCO2 during hypercapnia is attenuated in obese individuals compared with lean individuals

Epidemiology, Microbiology, and Clinical Outcomes Among Patients With Intravenous Drug Use-Associated Infective Endocarditis in New Brunswick

Background: Within the context of Canada’s opioid crisis, medical complications associated with intravenous drug use (IVDU) are increasing. Infective endocarditis (IE) is a serious complication of IVDU, and understanding the characteristics of these patients could aid health systems, clinicians, and patients in the optimization of treatment and prevention of IVDU-IE. / Methods: At a tertiary care hospital in southern New Brunswick, we conducted a retrospective chart review to identify patients with IVDU-IE admitted between January 1, 2013, and December 31, 2017. We collected data related to the epidemiology, microbiology, clinical manifestations, echocardiography, complications during hospital admission, and outcomes. / Results: Forty-two cases of IVDU-IE met inclusion criteria. The rate of IVDU-IE increased from 2.28 per 100,000 population in 2014 to 4.00 in 2017, which, although not statistically significant, reflects patterns in other jurisdictions. Most patients (72.4%) were male, and the mean age was 38.3 (±11.5) years. Most patients (79.3%) injected opioids. The most common clinical sign was fever (90.5%), and Staphylococcus aureus (61.9%) was the most common microorganism. The tricuspid valve was most commonly infected (58.5%), 50% of cases had heart failure as a complication during admission, and 45.2% of cases required valve replacement or repair. The 2-year survival rate after admission for initial IVDU-IE episode was 62.0% (95% confidence interval: 36.5-79.7). / Conclusion: IVDU-IE is common in New Brunswick and may be increasing. Despite the relatively young age of this patient population, IVDU-IE is associated with significant morbidity and mortality. Expanding effective harm reduction and addiction treatment strategies for this cohort is recommended. // Contexte: Dans le contexte de la crise des opioïdes au Canada, les complications médicales liées à l'utilisation de drogues par voie intraveineuse (UDIV) sont en augmentation. L'endocardite infectieuse (EI) est une complication grave de l'UDIV, et la compréhension des caractéristiques de ces patients pourrait aider les systèmes de santé, les cliniciens et les patients à optimiser le traitement et la prévention de l’EI liée à l’UDIV (EI-UDIV). / Méthodes: Dans un hôpital de soins tertiaires du sud du Nouveau-Brunswick, nous avons effectué un examen rétrospectif des dossiers afin d'identifier les patients atteints de l’EI-UDIV admis entre le 1er janvier 2013 et le 31 décembre 2017. Nous avons recueilli des données relatives à l'épidémiologie, la microbiologie, les manifestations cliniques, l'échocardiographie, les complications lors de l'admission à l'hôpital et les bilans. / Résultats: Quarante-deux cas d'EI-UDIV ont répondu aux critères d'inclusion. Le taux d'EI-UDIV est passé de 2,28 pour 100 000 habitants en 2014 à 4,00 en 2017, ce qui, bien que non significatif statistiquement, reflète les tendances observées dans d'autres juridictions. La plupart des patients (72,4 %) étaient des hommes, et l'âge moyen était de 38,3 ans (±11,5). La plupart des patients (79,3 %) s'injectaient des opioïdes. Le signe clinique le plus fréquent était la fièvre (90,5 %), et le Staphylococcus aureus (61,9 %) était le micro-organisme le plus couramment observé. La valve tricuspide était le plus souvent infectée (58,5 %), 50 % des cas avaient une insuffisance cardiaque en tant que complication lors de l'admission, et 45,2 % des cas ont nécessité un remplacement ou une réparation de la valve. Le taux de survie à deux ans après l'admission pour l'épisode initial d'EI-UDIV était de 62,0 % (intervalle de confiance à 95 % : 36,5-79,7). / Conclusion: L'EI-UDIV est fréquent au Nouveau-Brunswick et pourrait être en augmentation. Malgré l'âge relativement jeune de cette population de patients, l'UDIV-IE est associée à une morbidité et une mortalité importantes. Il est recommandé d'étendre les stratégies efficaces de réduction des risques et de traitement des dépendances pour cette cohorte