687 research outputs found
European Collaboration in Ocean Cores Science: roots, highlights, off-springs and vision
July 4th, 1947, exactly 75 years after the legendary cruise of H.M.S. Challenger and at a time when ocean science seemed to definitively shift to the shores of Massachusetts and California, the Swedish 5-masted schooner and school-ship Albatross set sail from Göteborg for a 15-months ambitious voyage of circumnavigation of the world oceans. Staffed with cadets and scientists and headed by Hans Pettersson, the Albatross had on board a revolutionary tool: Kullenbergâs piston corer, a 30m-long device which had already allowed the recovery of a 20m-long sediment core. Previously, the Meteor had recovered cores of a maximal length of 0.90m (1925), while in the thirties C.S. Piggot of the Carnegie Institution had âshotâ cores up to 3m length in the North-Atlantic with a gun-like device. Sedimentological, geochemical, mineralogical, micropalaeontological analyses and radio-active dating would be carried out not only in Swedish institutes, but also in Vienna, Göttingen, Hanover, Wageningen, Ghent, Paris, London and La Jolla, in the true spirit of the data exploitation scheme which had shaped the success of the cruise of the Challenger. The stage was set for palaeo-environmental research on long sediment cores, archives of past climate and oceans.In the mid-sixties, ocean cores science takes a giant leap with the Deep Sea Drilling Program (DSDP). 20 years after the Albatross, in the fall of 1968, the Glomar Challenger sails from Dakar for the South Atlantic to verify the hypothesis of seafloor spreading and plate tectonics. Europe would join the Ocean Drilling Program (ODP), which set sail in 1984, subsequent to the International Phase of Ocean Drilling (IPOD, 1975-1983). For the first time, the European Science Foundation moves in, providing to numerous smaller European partners a platform of participation in ODP through ECOD, the European Consortium for Ocean Drilling.Some 50 years after the Albatross, the âCalypsoâ piston corer on board of R/V Marion Dufresne would set the record of piston coring length, with an unrivaled core of over 64m length. The IMAGES programme would boost palaeoclimate research worldwide.At the turn of the century, ECORD - an off-spring of ECOD which had left the parental house - took the lead of the Mission Specific Platform (MSP) scheme in the Integrated Ocean Drilling Program (IODP), pushing frontiers of ocean drilling to extreme environments such as the poles and coral reefs. While not directly involved in the operational aspects, ESF soon took a prominent place in the supporting science, not the least through the EUROCORES programme and research networks.At the onset of the 21st century, while IODP and the international ocean drilling and coring community define a new strategy for post-2013 ocean coring science, Europe moves in with a new revolutionary tool, the MeBo (Meeresboden BohrgerĂ€t), a remotely operated seabed drilling tool capable of drilling and coring from a variety of large vessels. EUROFLEETS provides new opportunities for coordinated naval operations for ocean science. And in parallel, Europe develops the plans for an ambitious drilling platform for the Arctic: Aurora Borealis.Any lucid vision on the future of Ocean Cores Science, which plays a key role in the unraveling of the dynamics of our planet, will build upon the lessons of the past, reflect upon the strengths and weaknesses of the present, and ride upon the excitement of Europeâs young generation, driver of the future
Towards a novel carbon device for the treatment of sepsis
Sepsis is a systemic inflammatory response to infection in which the balance of pro- andanti-inflammatory mediators, which normally isolate and eliminate infection, is disrupted[1]. Gram negative sepsis is initiated by bacterial endotoxin release which activatesmacrophages and circulating monocytes to release TNF and IL-1ÎČ followed by IL-6 andother inflammatory cytokines [2]. As the disease progresses, an unregulatedinflammatory response results in, tissue injury, haematological dysfunction and organdysfunction. Severe sepsis, involving organ hypoperfusion may be further complicatedby hypotension that is unresponsive to adequate fluid replacement, resulting in septicshock and finally death [3].Despite improvements in anti-microbial and supportive therapies, sepsis remains asignificant cause of morbidity and mortality in ICUs worldwide [4]. The complexity ofprocesses mediating the progression of sepsis suggests that an extracorporeal devicecombining blood filtration with adsorption of a wide range of toxins, and inflammatorymediators offers the most comprehensive treatment strategy. However, no such deviceexists at present. A novel, uncoated, polymer pyrolysed synthetic carbon device isproposed which combines the superior adsorption properties of uncoated activatedcarbons with the capacity to manipulate porous structure for controlled adsorption oftarget plasma proteins and polypeptides [5]. Preliminary haemocompatibility andadsorptive capacity was assessed using a carbon matrix prototype
Berezin Quantization of Gauged WZW and Coset Models
Gauged WZW and coset models are known to be useful to prove holomorphic
factorization of the partition function of WZW and coset models. In this note
we show that these gauged models can be also important to quantize the theory
in the context of the Berezin formalism. For gauged coset models Berezin
quantization procedure also admits a further holomorphic factorization in the
complex structure of the moduli space.Comment: 15+1 pages, no figures, revte
A cross-sectional study of peripartum blood transfusion in the Eastern Cape, South Africa
Background. Obstetric haemorrhage (OH) remains a major contributor to maternal morbidity and mortality. Blood transfusion is critical in OH management; yet, data on peripartum transfusion are lacking. A pilot study reported high rates of peripartum transfusion in a sample of South African (SA) hospitals, which was independently associated with HIV status.Objectives. To assess the incidence of peripartum transfusion in a sample of Eastern Cape, SA hospitals to evaluate generalisability of preceding study findings.Methods. Hospital chart reviews were conducted of all deliveries at three large regional hospitals from February to June 2013. Additional clinical data were collected for patients who sustained OH and/or were transfused.Results. A total of 7 234 women were enrolled in the study; 1 988 (27.5%) were HIV-positive. Of the 767 HIV-positive women with a CD4 count <350 cells/ÎŒL, 86.0% were on full antiretroviral therapy and 9.9% received drugs for prevention of mother-to-child transmission. The overall transfusion rate was 3.2%, with significant variability by hospital: Frere Hospital (1.5%), Dora Nginza Hospital (3.8%) and Cecilia Makiwane Hospital (4.6%). The number of red blood cell units per transfused patient and per delivery varied significantly by hospital. Bivariate analysis showed significant association between transfusion and HIV status. In a multivariate analysis, controlling for OH, age, mode of delivery, gestational age, parity and birthweight, this association (odds ratio 1.45; 95% confidence interval 0.78 - 2.71) was no longer significant.Conclusion. These findings confirm high rates of peripartum transfusion in SA. While this can be possibly ascribed to variability in practice and patient profile, variation in care and improvement in HIV treatment should be considered
Socioeconomic status, mental wellbeing and transition to secondary school: analysis of the School Health Research Network/Health Behaviour in School-aged Children survey in Wales
Young peopleâs wellbeing is often lowest where they assume a relatively low position within their schoolâs socioeconomic hierarchy, for example, among poorer children attending more affluent schools. Transition to secondary school is a period during which young people typically enter an environment which is more socio-economically diverse than their primary school. Young people joining a school with a higher socioeconomic status intake relative to their primary school may assume a relatively lowered position within their schoolsâ socioeconomic hierarchy, experiencing a detriment to their wellbeing as a consequence. This paper draws on data from 45,055 pupils in Years 7 and 8, from 193 secondary schools in Wales, who completed the 2017 Student Health Research Network (SHRN) Student Health and Wellbeing (SHW) Survey. Pupils reported which primary school they previously attended, and survey data on wellbeing were linked to publicly available data on the Free School Meal entitlement of schools attended. In cross-classified linear mixed-effects models, with primary and secondary school as levels, mental wellbeing varied significantly according to both primary and secondary school attended. A higher school-level deprivation was associated with worse mental wellbeing in both cases. Mental wellbeing was significantly predicted by the relative affluence of a childâs primary and secondary school, with movement to a secondary school of higher overall socioeconomic status associated with lowered wellbeing. These findings highlight transition to secondary school as a key point in which socioeconomic inequality in wellbeing ma
Fisheries interactions of Delphinus delphis in the north-east Atlantic with an emphasis on Galicia, north-west Spain.
Bycatch from interactions with fisherie
s remains the biggest global threat to marine
mammals. Galicia, north
-
west Spain, is one of the worldâs main fishing regions and a high
level of cetacean
-
fisheries interactions has been reported from on
-
board observers, interviews
with fisheries stakeholde
rs and analysis of stranded and by
-
caught carcasses.
Delphinus
delphis
is the most abundant cetacean in the area and since 1990 necropsies of over 1800
stranded and by
-
caught
Delphinus
have been conducted. Life history data (age, maturity, and
pregnancy ra
te data) from stranded and by
-
caught cetaceans can be used to construct life
tables and to estimate overall mortality and fisheries mortality rates. Age and maturity were
determined from stranded and by
-
caught
Delphinus
between 1990 and 2009. Males and
fem
ales reach sexual maturity at 8.5 and 7.5 years of age, respectively, and no temporal
difference in age at sexual maturity was observed. Results indicate 13% annual mortality in
the
Delphinus delphis
north
-
east Atlantic population and necropsy data suggest
s that 60% of
mortality (i.e. 7.2% annual mortality) is attributable to fisheries interactions, predominantly
from pair trawls and gillnets. By
-
caught
Delphinus
were found to die significantly younger
than non
-
by
-
caught animals (p=<0.001) although no sex
-
r
elated difference in bycatch rate
was observed (p=0.051). The estimated annual mortality due to fisheries interactions greatly
exceeds the 2% limit set by ASCOBANS and the IWC and high bycatch rates are also
reported for other countries e.g. the UK, France
and Portugal. Although
Delphinus delphis
in
the north
-
east Atlantic is one continuous population, the high level of bycatch occurring in
parts of the range is most likely unsustainable and will be discussed. There is a need to carry
out on
-
board monitorin
g, notably in the north
-
west Iberian Peninsula (Galicia and Portugal),
to incorporate cetacean bycatch into fisheries advice and, above all, to start introducing
mitigation measures
Reichenbach's Common Cause Principle in Algebraic Quantum Field Theory with Locally Finite Degrees of Freedom
In the paper it will be shown that Reichenbach's Weak Common Cause Principle
is not valid in algebraic quantum field theory with locally finite degrees of
freedom in general. Namely, for any pair of projections A and B supported in
spacelike separated double cones O(a) and O(b), respectively, a correlating
state can be given for which there is no nontrivial common cause (system)
located in the union of the backward light cones of O(a) and O(b) and commuting
with the both A and B. Since noncommuting common cause solutions are presented
in these states the abandonment of commutativity can modulate this result:
noncommutative Common Cause Principles might survive in these models
Categorical formulation of quantum algebras
We describe how dagger-Frobenius monoids give the correct categorical
description of certain kinds of finite-dimensional 'quantum algebras'. We
develop the concept of an involution monoid, and use it to construct a
correspondence between finite-dimensional C*-algebras and certain types of
dagger-Frobenius monoids in the category of Hilbert spaces. Using this
technology, we recast the spectral theorems for commutative C*-algebras and for
normal operators into an explicitly categorical language, and we examine the
case that the results of measurements do not form finite sets, but rather
objects in a finite Boolean topos. We describe the relevance of these results
for topological quantum field theory.Comment: 34 pages, to appear in Communications in Mathematical Physic
Prevalence of gambling behaviours and their associations with socioemotional harm among 11 to 16 year olds in Wales: findings from the School Health Research Network survey
Background:
Gambling opportunities are increasingly available and acceptable to many adolescents. Adolescent problem gambling has been associated with poor outcomes, such as lower reported physical and mental health. While much research has focussed on âproblemâ gambling, analysing the distribution and determinants of experimentation with gambling is important in order to understand its normalization and population level consequences. This study describes the distribution of inequalities and socioemotional harms associated with adolescent gambling.
Methods:
Data were drawn from a subsample of students (N = 37 363) who completed gambling questions as part of the 2017 School Health Research Network Student Health and Wellbeing Survey, representing 193 secondary schools in Wales. Using imputations, we estimated a series of single-predictor and multi-predictor regressions for count of gambling behaviours, any gambling in the past 12 months and socioemotional harms of gambling.
Results:
Approximately two-fifths (41.0%) of respondents reported gambling in the past 12 months, of whom 16.2% reported feeling bad as a result of their own gambling. We found significant sex differences in gambling, with boys gambling more frequently than girls. Adolescents from more affluent families reported a higher count of gambling behaviours and socioemotional harms, although paradoxically, increasing affluence was also associated with lower prevalence of gambling in the last year. Non-White British ethnicities and students who felt less connected to school were more likely to engage in gambling and experience socioemotional harms.
Conclusions:
Our findings provide important new insights regarding risk factors in adolescence associated with gambling behaviours and socioemotional harms
Plasma scale length effects on protons generated in ultra-intense laserâplasmas
The energy spectra of protons generated by ultra-intense (1020 W cmâ2) laser interactions with a preformed plasma of scale length measured by shadowgraphy are presented. The effects of the preformed plasma on the proton beam temperature and the number of protons are evaluated. Two-dimensional EPOCH particle-in-cell code simulations of the proton spectra are found to be in agreement with measurements over a range of experimental parameter
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