77 research outputs found
Growth rings show limited evidence for ungulates' potential to suppress shrubs across the Arctic
Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5 degrees C-9 degrees C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates' potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions
Location of studies and evidence of effects of herbivory on Arctic vegetation: a systematic map
Herbivores modify the structure and function of tundra ecosystems. Understanding their impacts is necessary to assess the responses of these ecosystems to ongoing environmental changes. However, the effects of herbivores on plants and ecosystem structure and function vary across the Arctic. Strong spatial variation in herbivore effects implies that the results of individual studies on herbivory depend on local conditions, i.e., their ecological context. An important first step in assessing whether generalizable conclusions can be produced is to identify the existing studies and assess how well they cover the underlying environmental conditions across the Arctic. This systematic map aims to identify the ecological contexts in which herbivore impacts on vegetation have been studied in the Arctic. Specifically, the primary question of the systematic map was: “What evidence exists on the effects of herbivores on Arctic vegetation?”
Facilitating knowledge exchange between health-care sectors, organisations and professions: A longitudinal mixed-methods study of boundary-spanning processes and their impact on health-care quality
Background: Relatively little is known about how people and groups who function in boundary-spanning positions between different sectors, organisations and professions contribute to improved quality of health care and clinical outcomes.
Objectives: To explore whether or not boundary-spanning processes stimulate the creation and exchange of knowledge between sectors, organisations and professions and whether or not this leads, through better integration of services, to improvements in the quality of care.
Design: A 2-year longitudinal nested case study design using mixed methods.
Setting: An inner-city area in England (‘Coxford’) comprising 26 general practices in ‘Westpark’ and a comparative sample of 57 practices.
Participants: Health-care and non-health-care practitioners representing the range of staff participating in the Westpark Initiative (WI) and patients.
Interventions: The WI sought to improve services through facilitating knowledge exchange and collaboration between general practitioners, community services, voluntary groups and acute specialists during the period late 2009 to early 2012. We investigated the impact of the four WI boundary-spanning teams on services and the processes through which they produced their effects.
Main outcome measures: (1) Quality-of-care indicators during the period 2008–11; (2) diabetes admissions data from April 2006 to December 2011, adjusted for deprivation scores; and (3) referrals to psychological therapies from January 2010 to March 2012.
Data sources: Data sources included 42 semistructured staff interviews, 361 hours of non-participant observation, 36 online diaries, 103 respondents to a staff survey, two patient focus groups and a secondary analyses of local and national data sets.
Results: The four teams varied in their ability to, first, exchange knowledge across boundaries and, second, implement changes to improve the integration of services. The study setting experienced conditions of flux and uncertainty in which known horizontal and vertical structures underwent considerable change and the WI did not run its course as originally planned. Although knowledge exchanges did occur across sectoral, organisational and professional boundaries, in the case of child and family health services, early efforts to improve the integration of services were not sustained. In the case of dementia, team leadership and membership were undermined by external reorganisations. The anxiety and depression in black and minority ethnic populations team succeeded in reaching its self-defined goal of increasing referrals from Westpark practices to the local well-being service. From October to December 2010 onwards, referrals have been generally higher in the six practices with a link worker than in those without, but the performance of Westpark and Coxford practices did not differ significantly on three national quality indicators. General practices in a WI diabetes ‘cluster’ performed better on three of 17 Quality and Outcomes Framework (QOF) indicators than practices in the remainder of Westpark and in the wider Coxford primary care trust. Surprisingly, practices in Westpark, but not in the diabetes cluster, performed better on one indicator. No statistically significant differences were found on the remaining 13 QOF indicators. The time profiles differed significantly between the three groups for elective and emergency admissions and bed-days.
Conclusions: Boundary spanning is a potential solution to the challenge of integrating health-care services and we explored how such processes perform in an ‘extreme case’ context of uncertainty. Although the WI may have been a necessary intervention to enable knowledge exchange across a range of boundaries, it was not alone sufficient. Even in the face of substantial challenges, one of the four teams was able to adapt and build resilience. Implications for future boundary-spanning interventions are identified. Future research should evaluate the direct, measurable and sustained impact of boundary-spanning processes on patient care outcomes (and experiences), as well as further empirically based critiques and reconceptualisations of the socialisation→externalisation→combination→internalisation (SECI) model, so that the implications can be translated into practical ideas developed in partnership with NHS managers.
Funding: The National Institute for Health Research Health Services and Delivery Research programme
Base-Pair Resolution DNA Methylation Sequencing Reveals Profoundly Divergent Epigenetic Landscapes in Acute Myeloid Leukemia
We have developed an enhanced form of reduced representation bisulfite sequencing with extended genomic coverage, which resulted in greater capture of DNA methylation information of regions lying outside of traditional CpG islands. Applying this method to primary human bone marrow specimens from patients with Acute Myelogeneous Leukemia (AML), we demonstrated that genetically distinct AML subtypes display diametrically opposed DNA methylation patterns. As compared to normal controls, we observed widespread hypermethylation in IDH mutant AMLs, preferentially targeting promoter regions and CpG islands neighboring the transcription start sites of genes. In contrast, AMLs harboring translocations affecting the MLL gene displayed extensive loss of methylation of an almost mutually exclusive set of CpGs, which instead affected introns and distal intergenic CpG islands and shores. When analyzed in conjunction with gene expression profiles, it became apparent that these specific patterns of DNA methylation result in differing roles in gene expression regulation. However, despite this subtype-specific DNA methylation patterning, a much smaller set of CpG sites are consistently affected in both AML subtypes. Most CpG sites in this common core of aberrantly methylated CpGs were hypermethylated in both AML subtypes. Therefore, aberrant DNA methylation patterns in AML do not occur in a stereotypical manner but rather are highly specific and associated with specific driving genetic lesions
Triple-A syndrome with prominent ophthalmic features and a novel mutation in the AAAS gene: a case report.
Triple-A syndrome (Allgrove syndrome) is an autosomal recessive disorder characterized by adrenal insufficiency, alacrima, achalasia, and - occasionally - autonomic instability. Mutations have been found in the AAAS gene on 12q13
Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic
Global warming has pronounced effects on tundra vegetation, and rising mean temperatures
increase plant growth potential across the Arctic biome. Herbivores may counteract the warming
impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional
climatic conditions. To study how ungulates interact with temperature to influence growth of
tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites,
comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates
suppressing shrub radial growth was only observed at intermediate summer temperatures
(6.5 ◦C–9 ◦C), and even at these temperatures the effect was not strong. Multiple factors, including
forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling
effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly
explaining the weakness of observed ungulate effects. Earlier local studies have shown that
ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate
that ungulates’ potential to suppress shrub radial growth is not always evident, and may be limited
to certain climatic conditions.Research Council of Norwayhttp://iopscience.iop.org/1748-9326dm2022Mammal Research InstituteZoology and Entomolog
Developing common protocols to measure tundra herbivory across spatial scales
Understanding and predicting large-scale ecological responses to global environmental change requires comparative studies across geographic scales with coordinated efforts and standardized methodologies. We designed, applied and assessed standardized protocols to measure tundra herbivory at three spatial scales: plot, site (habitat), and study area (landscape). The plot and site-level protocols were tested in the field during summers 2014-2015 at eleven sites, nine of them comprising warming experimental plots included in the International Tundra Experiment (ITEX). The study area protocols were assessed during 2014-2018 at 24 study areas across the Arctic. Our protocols provide comparable and easy-to-implement methods for assessing the intensity of invertebrate herbivory within ITEX plots and for characterizing vertebrate herbivore communities at larger spatial scales. We discuss methodological constraints and make recommendations for how these protocols can be used and how sampling effort can be optimized to obtain comparable estimates of herbivory, both at ITEX sites and at large landscape scales. The application of these protocols across the tundra biome will allow characterizing and comparing herbivore communities across tundra sites and at ecologically relevant spatial scales, providing an important step towards a better understanding of tundra ecosystem responses to large-scale environmental change.CGB was funded by the Estonian Research Council (grant IUT 20-28), and
the European Regional Development Fund (Centre of Excellence EcolChange). JDMS was supported by the Research
Council of Norway (262064). OG and LB were supported by the French Polar Institute (program “1036
Interactions”) and PRC CNRS Russie 396 (program “ICCVAT”). DSH, NL, MAG, JB and JDR were supported by the
Natural Sciences and Engineering Research Council (Canada). NL, MAG, JB and JDR were supported by the Polar
Continental Shelf Program. NL was supported by the Canada Research Chair program and the Canada Foundation
for Innovation. NL and JB were supported by Environment Canada and Polar Knowledge Canada. NL and MAG were
supported by the Government of Nunavut, the Igloolik Community, and Université de Moncton. NL, MAG and JB
were supported by the Northern Scientific Training Program. JMA was funded by Carl Tryggers stiftelse för
vetenskaplig forskning and Qatar Petroleum (QUEX-CAS-QP-RD-18_19). IHM-S was funded by the UK Natural
Environmental Research Council Shrub Tundra (NE/M016323/1) grant. ISJ was funded by the University of Iceland
Research Fund. Fieldwork in Yamal peninsula (Erkuta, Sabetta and Belyi) for DE, NS and AS was supported by the
Russian Foundation for Basic Research (No: 18-05-60261 and No: 18-54-15013), Fram Centre project YaES (No:
362259), the Russian Center of Development of the Arctic, and the “Yamal-LNG” company. Fieldwork in Utqiaġvik
was supported by the U.S. Fish and Wildlife Service. Fieldwork in Svalbard was supported by the Norwegian
Research Council (AFG No: 246080/E10), the Norwegian Polar Institute, Climate-ecological Observatory for Arctic
Tundra – COAT, the Svalbard Environmental protection fund (project number 15/20), and the University Centre in
Svalbard (UNIS) and the AB-338/AB-838 students of 2018. Sampling at Billefjorden was supported by GACR 17-
20839S
High Speed Balancing Procedures
LectureThe paper describes elastic balancing procedures and experimental results for turbomachine rotors. The commonly known criteria of static and dynamic balancing no longer apply in this case. The rotating elements are balanced at full speed in their contract bearings. Dynamic bearing forces are measured with respect to direction and magnitude. Balancing weights are attached to the rotor in several planes and the thermally caused deflections, nonsynchronous vibrations and natural frequencies of bearing supports have to be accounted for. The rotor sensitivity can be determined by attachment of test unbalances. Dynamic bearing forces and shaft vibrations are measured and the shock excitations and log decrement calculations yield the stability limits
Beginning in Archaeology. Kathleen M. Kenyon. Sections on American Archaeology by Saul S. and Gladys D. Weinberg. Revised edition, Phoenix House and Frederick A. Praeger, London and New York, 1953. 217 pp., frontis., 14 figs., 11 pls. 7.50. - Still Digging. Sir Mortimer Wheeler. Dutton, New York, 1956. 236 pp., 15 pls. $4.00.
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