65 research outputs found
Hoki (Macruronus novaezelandiae) Diet Variability and Associated Middle-Depth Demersal Fish Species Depth Distribution in the Ecosystem on the Chatham Rise, New Zealand.
Fisheries management in New Zealand is mostly on a single species basis. Globally there is a shift towards multispecies or ecosystem based fisheries management. For this to happen an understanding of how the ecosystem is organised and functions is needed. Trophic food web and diet studies have been used effectively to begin to understand the
functioning of marine ecosystems. Who eats whom, however, is not the full extent of ecosystem function. Understanding of species distribution patterns, of both predators and prey species are also needed to begin to understand the full function of the marine ecosystem. The first part of this study investigated the diet of hoki (Macruronus novaezelandiae) over the Chatham Rise, New Zealand, between 200-800m. It characterised the diet of hoki as well as investigated potential sources of diet variability. Hoki diet was found to
consist largely of mesopelagic teleosts, mainly of the family Myctophidae, natant decapods and euphausids, suggesting a pelagic feeding strategy, as other studies have also found. Differences were found in diet composition between this study and other studies on hoki diet, potentially suggesting differences in prey distribution between study
areas. Differences in diet were found between fish from different depths and different sized fish from the same depth. No consistent pattern of diet differences was found between the different areas studied, suggesting that the patterns found may be aliasing depth and size patterns as well as reflecting differences in hoki size class distribution. The distribution of hoki was not homogeneous over the study area, with small fish found mainly in the western part of the study area in shallower water, while large fish were predominately found at greater depths over the whole study area. The second part of this study looked at the overall species distribution of 30 demersal fish species over the Chatham Rise, specifically examining for evidence of the mid-domain effect. The study also investigated body-size depth trends between these species, and split by class Osteichthyes and Chondrichthyes. The mid-domain effect predicts species richness, and thus distribution, is due to geometric constraints with the greatest species
richness to be found at the centre of a geographically constrained domain. The overall
species distribution was found to be explained by the mid-domain effect. The distribution pattern of larger individuals being found in deeper water, with smaller individuals found in shallower water has often been seen in marine systems. We found no interspecific pattern for body-size depth distribution with the entire species assemblage, nor when the assemblage was split by class into Osteichthyes and Chondrichthyes, which supports our findings of the mid-domain effect. At a species level patterns of positive, negative and no trend were found with body-size depth relationships. At a community level species distribution over the studied depth range was largely explained by the geometric constraints of the mid-domain effect, while at a species level distribution over depth was
often a reflection of body size. Some species had large individuals deep while other species had small. Overall this supports the hypothesis that competition or adaptation works more strongly at a population or species level, than on the overall community who's species distribution can more often be attributed to random chance. This study begins to explain predator species distribution over the Chatham Rise and looks at the diet of one dominant species in the Chatham Rise ecosystem. This provides some of the basic knowledge needed for fisheries management to move towards a more
ecosystem based approach. Further research should include investigation into prey species distribution and abundance to clarify some of the questions raised in the diet part of this study about the cause of diet variability and whether it was related to either prey abundance or patchy prey distribution. Research into the diet of other fish would be useful to ascertain which species compete with hoki for food and would provide fisheries managers with a list of species that may be affected indirectly through changes in hoki quota of abundance
Diet of Two Large Sympatric Teleosts, the Ling (Genypterus blacodes) and Hake (Merluccius australis)
Ling and hake are tertiary consumers, and as a result both may have an important structuring role in marine communities. The diets of 2064 ling and 913 hake from Chatham Rise, New Zealand, were determined from examination of stomach contents. Ling was a benthic generalist, and hake a demersal piscivore. The diet of ling was characterised by benthic crustaceans, mainly Munida gracilis and Metanephrops challengeri, and demersal fishes, mainly Macrourids and scavenged offal from fishing vessels. The diet of hake was characterised by teleost fishes, mainly macrourids and merlucciids. Multivariate analyses using distance-based linear models found the most important predictors of diet variability were depth, fish length, and vessel type (whether the sample was collected from a commercial or research vessel) for ling, and fish length and vessel type for hake. There was no interspecific predation between ling and hake, and resource competition was largely restricted to macrourid prey, although the dominant macrourid species predated by ling and hake were different. Cluster analysis of average diet of intraspecific groups of ling and hake confirmed the persistent diet separation. Although size is a central factor in determining ecological processes, similar sized ling and hake had distinctly different foraging ecology, and therefore could influence the ecosystem in different ways, and be unequally affected by ecosystem fluctuations
Dipeptidyl peptidase-1 inhibition in patients hospitalised with COVID-19:a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial
This study was funded by an investigator-initiated research grant from Insmed (Bridgewater, NJ, USA). The authors acknowledge the funding and logistical support from the UK National Institute for Health and Care Research.Background: Neutrophil serine proteases are involved in the pathogenesis of COVID-19 and increased serine protease activity has been reported in severe and fatal infection. We investigated whether brensocatib, an inhibitor of dipeptidyl peptidase-1 (DPP-1; an enzyme responsible for the activation of neutrophil serine proteases), would improve outcomes in patients hospitalised with COVID-19. Methods: In a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial, across 14 hospitals in the UK, patients aged 16 years and older who were hospitalised with COVID-19 and had at least one risk factor for severe disease were randomly assigned 1:1, within 96 h of hospital admission, to once-daily brensocatib 25 mg or placebo orally for 28 days. Patients were randomly assigned via a central web-based randomisation system (TruST). Randomisation was stratified by site and age (65 years or ≥65 years), and within each stratum, blocks were of random sizes of two, four, or six patients. Participants in both groups continued to receive other therapies required to manage their condition. Participants, study staff, and investigators were masked to the study assignment. The primary outcome was the 7-point WHO ordinal scale for clinical status at day 29 after random assignment. The intention-to-treat population included all patients who were randomly assigned and met the enrolment criteria. The safety population included all participants who received at least one dose of study medication. This study was registered with the ISRCTN registry, ISRCTN30564012. Findings: Between June 5, 2020, and Jan 25, 2021, 406 patients were randomly assigned to brensocatib or placebo; 192 (47·3%) to the brensocatib group and 214 (52·7%) to the placebo group. Two participants were excluded after being randomly assigned in the brensocatib group (214 patients included in the placebo group and 190 included in the brensocatib group in the intention-to-treat population). Primary outcome data was unavailable for six patients (three in the brensocatib group and three in the placebo group). Patients in the brensocatib group had worse clinical status at day 29 after being randomly assigned than those in the placebo group (adjusted odds ratio 0·72 [95% CI 0·57-0·92]). Prespecified subgroup analyses of the primary outcome supported the primary results. 185 participants reported at least one adverse event; 99 (46%) in the placebo group and 86 (45%) in the brensocatib group. The most common adverse events were gastrointestinal disorders and infections. One death in the placebo group was judged as possibly related to study drug. Interpretation: Brensocatib treatment did not improve clinical status at day 29 in patients hospitalised with COVID-19.Publisher PDFPeer reviewe
A hybrid architecture (CO-CONNECT) to facilitate rapid discovery and access to data across the United Kingdom in response to the COVID-19 pandemic: development study
Final Targeting Strategy for the SDSS-IV APOGEE-2N Survey
APOGEE-2 is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with
the goal of producing a chemo-dynamical mapping of the Milky Way Galaxy. The
targeting for APOGEE-2 is complex and has evolved with time. In this paper, we
present the updates and additions to the initial targeting strategy for
APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two
implementation modes: (i) "Ancillary Science Programs" competitively awarded to
SDSS-IV PIs through proposal calls in 2015 and 2017 for the pursuit of new
scientific avenues outside the main survey, and (ii) an effective 1.5-year
expansion of the survey, known as the Bright Time Extension, made possible
through accrued efficiency gains over the first years of the APOGEE-2N project.
For the 23 distinct ancillary programs, we provide descriptions of the
scientific aims, target selection, and how to identify these targets within the
APOGEE-2 sample. The Bright Time Extension permitted changes to the main survey
strategy, the inclusion of new programs in response to scientific discoveries
or to exploit major new datasets not available at the outset of the survey
design, and expansions of existing programs to enhance their scientific success
and reach. After describing the motivations, implementation, and assessment of
these programs, we also leave a summary of lessons learned from nearly a decade
of APOGEE-1 and APOGEE-2 survey operations. A companion paper, Santana et al.
(submitted), provides a complementary presentation of targeting modifications
relevant to APOGEE-2 operations in the Southern Hemisphere.Comment: 59 pages; 11 Figures; 7 Tables; 2 Appendices; Submitted to Journal
and Under Review; Posting to accompany papers using the SDSS-IV/APOGEE-2 Data
Release 17 scheduled for December 202
Cerebral microbleeds and intracranial haemorrhage risk in patients anticoagulated for atrial fibrillation after acute ischaemic stroke or transient ischaemic attack (CROMIS-2):a multicentre observational cohort study
Background:
Cerebral microbleeds are a potential neuroimaging biomarker of cerebral small vessel diseases that are prone to intracranial bleeding. We aimed to determine whether presence of cerebral microbleeds can identify patients at high risk of symptomatic intracranial haemorrhage when anticoagulated for atrial fibrillation after recent ischaemic stroke or transient ischaemic attack.
Methods:
Our observational, multicentre, prospective inception cohort study recruited adults aged 18 years or older from 79 hospitals in the UK and one in the Netherlands with atrial fibrillation and recent acute ischaemic stroke or transient ischaemic attack, treated with a vitamin K antagonist or direct oral anticoagulant, and followed up for 24 months using general practitioner and patient postal questionnaires, telephone interviews, hospital visits, and National Health Service digital data on hospital admissions or death. We excluded patients if they could not undergo MRI, had a definite contraindication to anticoagulation, or had previously received therapeutic anticoagulation. The primary outcome was symptomatic intracranial haemorrhage occurring at any time before the final follow-up at 24 months. The log-rank test was used to compare rates of intracranial haemorrhage between those with and without cerebral microbleeds. We developed two prediction models using Cox regression: first, including all predictors associated with intracranial haemorrhage at the 20% level in univariable analysis; and second, including cerebral microbleed presence and HAS-BLED score. We then compared these with the HAS-BLED score alone. This study is registered with ClinicalTrials.gov, number NCT02513316.
Findings:
Between Aug 4, 2011, and July 31, 2015, we recruited 1490 participants of whom follow-up data were available for 1447 (97%), over a mean period of 850 days (SD 373; 3366 patient-years). The symptomatic intracranial haemorrhage rate in patients with cerebral microbleeds was 9·8 per 1000 patient-years (95% CI 4·0–20·3) compared with 2·6 per 1000 patient-years (95% CI 1·1–5·4) in those without cerebral microbleeds (adjusted hazard ratio 3·67, 95% CI 1·27–10·60). Compared with the HAS-BLED score alone (C-index 0·41, 95% CI 0·29–0·53), models including cerebral microbleeds and HAS-BLED (0·66, 0·53–0·80) and cerebral microbleeds, diabetes, anticoagulant type, and HAS-BLED (0·74, 0·60–0·88) predicted symptomatic intracranial haemorrhage significantly better (difference in C-index 0·25, 95% CI 0·07–0·43, p=0·0065; and 0·33, 0·14–0·51, p=0·00059, respectively).
Interpretation:
In patients with atrial fibrillation anticoagulated after recent ischaemic stroke or transient ischaemic attack, cerebral microbleed presence is independently associated with symptomatic intracranial haemorrhage risk and could be used to inform anticoagulation decisions. Large-scale collaborative observational cohort analyses are needed to refine and validate intracranial haemorrhage risk scores incorporating cerebral microbleeds to identify patients at risk of net harm from oral anticoagulation.
Funding:
The Stroke Association and the British Heart Foundation
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Dipeptidyl peptidase-1 inhibition in patients hospitalised with COVID-19: a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial
Background
Neutrophil serine proteases are involved in the pathogenesis of COVID-19 and increased serine protease activity has been reported in severe and fatal infection. We investigated whether brensocatib, an inhibitor of dipeptidyl peptidase-1 (DPP-1; an enzyme responsible for the activation of neutrophil serine proteases), would improve outcomes in patients hospitalised with COVID-19.
Methods
In a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial, across 14 hospitals in the UK, patients aged 16 years and older who were hospitalised with COVID-19 and had at least one risk factor for severe disease were randomly assigned 1:1, within 96 h of hospital admission, to once-daily brensocatib 25 mg or placebo orally for 28 days. Patients were randomly assigned via a central web-based randomisation system (TruST). Randomisation was stratified by site and age (65 years or ≥65 years), and within each stratum, blocks were of random sizes of two, four, or six patients. Participants in both groups continued to receive other therapies required to manage their condition. Participants, study staff, and investigators were masked to the study assignment. The primary outcome was the 7-point WHO ordinal scale for clinical status at day 29 after random assignment. The intention-to-treat population included all patients who were randomly assigned and met the enrolment criteria. The safety population included all participants who received at least one dose of study medication. This study was registered with the ISRCTN registry, ISRCTN30564012.
Findings
Between June 5, 2020, and Jan 25, 2021, 406 patients were randomly assigned to brensocatib or placebo; 192 (47·3%) to the brensocatib group and 214 (52·7%) to the placebo group. Two participants were excluded after being randomly assigned in the brensocatib group (214 patients included in the placebo group and 190 included in the brensocatib group in the intention-to-treat population). Primary outcome data was unavailable for six patients (three in the brensocatib group and three in the placebo group). Patients in the brensocatib group had worse clinical status at day 29 after being randomly assigned than those in the placebo group (adjusted odds ratio 0·72 [95% CI 0·57–0·92]). Prespecified subgroup analyses of the primary outcome supported the primary results. 185 participants reported at least one adverse event; 99 (46%) in the placebo group and 86 (45%) in the brensocatib group. The most common adverse events were gastrointestinal disorders and infections. One death in the placebo group was judged as possibly related to study drug.
Interpretation
Brensocatib treatment did not improve clinical status at day 29 in patients hospitalised with COVID-19
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