1,117 research outputs found
The Structure and Evolution of Stars: Introductory Remarks
In this introductory chapter of the Special Issue entitled ‘The Structure and Evolution of Stars’, we highlight the recent major progress made in our understanding of the physics that governs stellar interiors. In so doing, we combine insight from observations, 1D evolutionary modelling and 2D + 3D rotating (magneto)hydrodynamical simulations. Therefore, a complete and compelling picture of the necessary ingredients in state-of-the-art stellar structure theory and areas in which improvementsstillneedtobemadearecontextualised. Additionally, the over-arching perspective linking all the themes of subsequent chapters is presented
7 Scoping review of homonymous hemianopia in childhood
Cerebral visual impairment (CVI) encompasses a heterogeneous group of disorders and a spectrum of types of visual impairments. Research is needed to characterise the different forms of CVI and identify the specific needs of these groups to inform individualised patient care. Homonymous hemianopia (HH) is a definable visual field defect that affect some children with CVI. As part of a new research programme, we conducted a scoping review of the literature on HH in children and young people to map current knowledge and identify evidence gaps.We used the PRISMA extension for Scoping Reviews methodology. Multiple online databases were searched using terms associated with 'homonymous hemianopia' and 'children'. This yielded 1588 papers which were screened by two reviewers. Of these 1001 were excluded at abstract screen and a further 415 excluded after full text review, with full text unavailable for 15. Data were extracted and charted from 157 studies and additional grey literature.Interim analysis shows reported studies are predominantly from high income countries with a paucity of higher-level evidence, and a preponderance of case reports. Most papers reported causative pathology and diagnosis of HH. There was minimal attention to or evidence relating to intervention. Child-specific grey literature on HH was limited.This review collates the current evidence-base for HH in children. It demonstrates the important evidence-gap relating to intervention in these cases that would help inform more individualised care. Similar scoping reviews may be prove useful in assessing the evidence relating to other definable groups within the CVI umbrella
Hepatic artery thrombosis following pediatric liver transplantation: Assessment of blood flow measurement in allografts
The purpose of this study was to define parameters which could be predictive of hepatic artery thrombosis, which continues to be a major complicating factor in pediatric liver transplantation. The hepatic blood flow of 14 pediatric liver patients (15 grafts) who weighted less than 15 kg was measured electromagnetically during orthotopic liver transplantation. The results of blood flow determination and the clinical data in 7 patients (8 grafts) who developed hepatic artery thrombosis were compared with those of 7 control patients. All patients with a hepatic arterial flow of less than 60 ml/min developed hepatic artery thrombosis (4/8 vs. 0/7; p < 0.05), and the patients with hepatic artery thrombosis exhibited higher total hepatic and portal vein flow per 100 gram of liver tissue (262 vs. 136 ml/min; p < 0.001 and 222 vs. 80 ml/min; p < 0.025, respectively) as well as longer cold preservation time (384 vs. 326 min; p < 0.025). The results of our study suggest that hepatic arterial flows of less than 60 ml/min are critical for the development of hepatic artery thrombosis, and that portal venous overflow and increased preservation times may contribute to the development of hepatic artery thrombosis
OKT3 and viral disease in pediatric liver transplant recipients
Seventy-four consecutive pediatric liver transplant recipients were reviewed to assess the effect of the monoclonal anti-T-lymphocyte antibody OKT3 on subsequent viral infection (9 patients were excluded due to postoperative demise during the 1st week). Twenty-two patients received OKT3 in addition to standard cyclosporine-prednisone immunosuppression for either steroid-resistant acute rejection (18) or to facilitate reduction of cyclosporine due to severe renal impairment (4). Invasive infections were diagnosed by histology or culture in tissue biopsies or bronchoalveolar lavage specimens. The overall incidence of viral infection was 58%, half of which was due to cytomegalovirus (CMV). Invasive viral disease was associated with increased mortality (37% vs. 3% p = 0.001). Viral-related deaths were due to CMV (5), disseminated adenovirus (3), disseminated enterovirus (1) and respiratory syncytial viral pneumonia (1). The use of OKT3 was associated with increased viral disease (59% vs. 33% p = 0.04) and invasive primary CMV disease (58% vs. 19% p = 0.04). Trends were observed toward increased overall viral infection (73% vs. 51% p = 0.08), primary CMV infection (58% vs. 25% p = 0.08) and overall mortality (27% vs. 9% p = 0.08) following OKT3 therapy. We conclude that pediatric liver transplant recipients who require OKT3 therapy may be at increased risk for invasive viral disease and especially invasive primary CMV disease
(Wild)fire is not an ecosystem service
In their paper entitled “Wildfires as an ecosystem
service”, Pausas and Keeley (2019)
summarize the benefits generated by – as
well as the evolutionary and socioecological
importance of – wildfires for humankind.
Although we recognize the importance of
wildfires in such a context, we argue that
presenting wildfire per se as an ecosystem
service is conceptually incorrect and can be
misleading for policy makers and resource
managers. Throughout their paper, the
authors repeatedly refer to (wild)fire as a
potential provider of multiple ecosystem
services (and not as an ecosystem service
itself, as indicated in their article’s title). We
believe that this is more than a dispute over
semantics, for such a contradiction could
lead to misperceptions about the definition
of the term “
ecosystem services”, which is
especially concerning in light of its real-world
applications to fire management.ÂS received support from the Portuguese
Foundation for Science and Technology
(FCT) through PhD grant SFRH/BD/
132838/2017, funded by the Ministry
of Science, Technology and Higher
Education, and by the European Social
Fund–Operational Program Human
Capital within the 2014–2020 EU
Strategic Framework. AR is funded by
Xunta de Galicia (post-doctoral
fellowship
ED481B2016/084-0).
This research
was developed as part of the project
FirESmart (PCIF/MOG/0083/2017), which
received funding from the FCT. The
authors declare that they have no conflicts
of interest.info:eu-repo/semantics/publishedVersio
The Ctf18 RFC-like complex positions yeast telomeres but does not specify their replication time
Peer reviewedPreprin
DEP and AFO Regulate Reproductive Habit in Rice
Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho), degenerative palea (dep), and abnormal floral organs (afo). Genetic analysis of them indicated that the stable pseudovivipary mutant pho was a double mutant containing both a Mendelian mutation in DEP and a non-Mendelian mutation in AFO. Further map-based cloning and microarray analysis revealed that dep mutant was caused by a genetic alteration in OsMADS15 while afo was caused by an epigenetic mutation in OsMADS1. Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice. For the first time, our results reveal two regulators for sexual and asexual reproduction modes in flowering plants. In addition, our findings also make it possible to manipulate the reproductive strategy of plants, at least in rice
Methods for biogeochemical studies of sea ice: The state of the art, caveats, and recommendations
AbstractOver the past two decades, with recognition that the ocean’s sea-ice cover is neither insensitive to climate change nor a barrier to light and matter, research in sea-ice biogeochemistry has accelerated significantly, bringing together a multi-disciplinary community from a variety of fields. This disciplinary diversity has contributed a wide range of methodological techniques and approaches to sea-ice studies, complicating comparisons of the results and the development of conceptual and numerical models to describe the important biogeochemical processes occurring in sea ice. Almost all chemical elements, compounds, and biogeochemical processes relevant to Earth system science are measured in sea ice, with published methods available for determining biomass, pigments, net community production, primary production, bacterial activity, macronutrients, numerous natural and anthropogenic organic compounds, trace elements, reactive and inert gases, sulfur species, the carbon dioxide system parameters, stable isotopes, and water-ice-atmosphere fluxes of gases, liquids, and solids. For most of these measurements, multiple sampling and processing techniques are available, but to date there has been little intercomparison or intercalibration between methods. In addition, researchers collect different types of ancillary data and document their samples differently, further confounding comparisons between studies. These problems are compounded by the heterogeneity of sea ice, in which even adjacent cores can have dramatically different biogeochemical compositions. We recommend that, in future investigations, researchers design their programs based on nested sampling patterns, collect a core suite of ancillary measurements, and employ a standard approach for sample identification and documentation. In addition, intercalibration exercises are most critically needed for measurements of biomass, primary production, nutrients, dissolved and particulate organic matter (including exopolymers), the CO2 system, air-ice gas fluxes, and aerosol production. We also encourage the development of in situ probes robust enough for long-term deployment in sea ice, particularly for biological parameters, the CO2 system, and other gases.This manuscript is a product of SCOR working group 140 on Biogeochemical Exchange Processes at Sea-Ice Interfaces
(BEPSII); we thank BEPSII chairs Jacqueline Stefels and Nadja Steiner and SCOR executive director Ed Urban for their
practical and moral support of this endeavour. This manuscript was first conceived at an EU COST Action 735 workshop
held in Amsterdam in April 2011; in addition to COST 735, we thank the other participants of the “methods” break-out
group at that meeting, namely Gerhard Dieckmann, Christoph Garbe, and Claire Hughes. Our editors, Steve Ackley and
Jody Deming, and our reviewers, Mats Granskog and two anonymous reviewers, provided invaluable advice that not only
identified and helped fill in some gaps, but also suggested additional ways to make what is by nature a rather dry subject
(methods) at least a bit more interesting and accessible. We also thank the librarians at the Institute of Ocean Sciences for
their unflagging efforts to track down the more obscure references we required. Finally, and most importantly, we thank
everyone who has braved the unknown and made the new measurements that have helped build sea-ice biogeochemistry
into the robust and exciting field it has become.This is the final published article, originally published in Elementa: Science of the Anthropocene, 3: 000038, doi: 10.12952/journal.elementa.00003
Recommended from our members
Wellbeing, mental health knowledge and caregiving experiences of siblings of people with psychosis, compared to their peers and parents: An exploratory study
Purpose
The wellbeing and caregiving experiences of family carers supporting people with psychosis has garnered increasing interest. Evidence indicates that the burden of caregiving can adversely impact on parents’ wellbeing, few studies have investigated whether this is also the case for siblings, who often take on caregiving responsibilities. This exploratory study investigated the wellbeing, mental health knowledge, and appraisals of caregiving in siblings of individuals with psychosis.
Method
Using a cross-sectional design, 90 siblings completed three validated questionnaires: Warwick–Edinburgh Mental Wellbeing Scale (WEMWBS), Mental Health Knowledge Schedule (MAKS), and Experience of Caregiving Inventory (ECI). Data obtained were compared to general population norms and parent-carers’ scores. Multi-variable regression analyses were conducted to examine relationships between questionnaire scores and demographic characteristics including age, sex, birth order, marital status, accommodation and educational level.
Results
Siblings, especially sisters, had significantly poorer mental wellbeing, compared to normative scores. Conversely, they had better mental health knowledge. Siblings and parent-carers had comparable high levels of negative appraisals of caregiving experiences, but siblings reported more satisfaction with personal experiences and relationships. Education level was a significant predictor for better mental health knowledge; there were no other relationships between siblings’ demographic factors and outcomes.
Conclusion
Study findings suggest that siblings have overlapping as well as distinct needs, compared to parent-carers. Further research is required to better understand siblings’ experiences so as to inform development of targeted interventions that enhance wellbeing and caregiving capacity
Variant -and individual dependent nature of persistent Anaplasma phagocytophilum infection
<p>Abstract</p> <p>Background</p> <p><it>Anaplasma phagocytophilum </it>is the causative agent of tick-borne fever in ruminants and human granulocytotropic anaplasmosis (HGA). The bacterium is able to survive for several months in immune-competent sheep by modifying important cellular and humoral defence mechanisms. Little is known about how different strains of <it>A. phagocytophilum </it>propagate in their natural hosts during persistent infection.</p> <p>Methods</p> <p>Two groups of five lambs were infected with each of two <it>16S </it>rRNA gene variants of <it>A. phagocytophilum</it>, i.e. <it>16S </it>variant 1 which is identical to GenBank no <ext-link ext-link-id="M73220" ext-link-type="gen">M73220</ext-link> and <it>16S </it>variant 2 which is identical to GenBank no <ext-link ext-link-id="AF336220" ext-link-type="gen">AF336220</ext-link>, respectively. The lambs were infected intravenously and followed by blood sampling for six months. <it>A. phagocytophilum </it>infection in the peripheral blood was detected by absolute quantitative real-time PCR.</p> <p>Results</p> <p>Both <it>16S </it>rRNA gene variants of <it>A. phagocytophilum </it>established persistent infection for at least six months and showed cyclic bacteraemias, but variant 1 introduced more frequent periods of bacteraemia and higher number of organisms than <it>16S </it>rRNA gene variant 2 in the peripheral blood.</p> <p>Conclusion</p> <p>Organisms were available from blood more or less constantly during the persistent infection and there were individual differences in cyclic activity of <it>A. phagocytophilum </it>in the infected animals. Two <it>16S </it>rRNA gene variants of <it>A. phagocytophilum </it>show differences in cyclic activity during persistent infection in lambs.</p
- …