Degeneracy Algorithm for Random Magnets

It has been known for a long time that the ground state problem of random magnets, e.g. random field Ising model (RFIM), can be mapped onto the max-flow/min-cut problem of transportation networks. I build on this approach, relying on the concept of residual graph, and design an algorithm that I prove to be exact for finding all the minimum cuts, i.e. the ground state degeneracy of these systems. I demonstrate that this algorithm is also relevant for the study of the ground state properties of the dilute Ising antiferromagnet in a constant field (DAFF) and interfaces in random bond magnets.Comment: 17 pages(Revtex), 8 Postscript figures(5color) to appear in Phys. Rev. E 58, December 1st (1998

Microsatellite markers for the Arctic copepod Calanus glacialis and cross-amplification with C. finmarchicus

Calanus glacialis is a major component of Arctic zooplankton and a keystone species in Arctic marine ecosystems. Due to the observed climate warming, its numbers are being reduced to the advantage of a sibling Atlantic species Calanus finmarchicus. We developed and characterized the first set of microsatellite markers in this species to investigate its population genetic structure and dispersal capabilities. Nine polymorphic loci displayed an average of 7.3 alleles (range between 2 and 13) and the levels of expected heterozygosity ranged from 0.039 to 0.806. These provide a valuable tool to understand present connectivity patterns across Arctic regions, look for signatures of past climate effects and predict the response to future climate-driven environmental changes. Additionally, due to the cross-amplification with C. finmarchicus, the markers can be used to discriminate between these sibling species.National Science Centre, Poland [2011/03/B/NZ8/02876]; FCT, Portugal [PTDC/MAR/72630/2006]; EU FP7 Project ATP [226248]; European Community (ASSEMBLE-MARINE) [227799]info:eu-repo/semantics/publishedVersio

Postglacial expansion of the arctic keystone copepod calanus glacialis

Calanus glacialis, a major contributor to zooplankton biomass in the Arctic shelf seas, is a key link between primary production and higher trophic levels that may be sensitive to climate warming. The aim of this study was to explore genetic variation in contemporary populations of this species to infer possible changes during the Quaternary period, and to assess its population structure in both space and time. Calanus glacialis was sampled in the fjords of Spitsbergen (Hornsund and Kongsfjorden) in 2003, 2004, 2006, 2009 and 2012. The sequence of a mitochondrial marker, belonging to the ND5 gene, selected for the study was 1249 base pairs long and distinguished 75 unique haplotypes among 140 individuals that formed three main clades. There was no detectable pattern in the distribution of haplotypes by geographic distance or over time. Interestingly, a Bayesian skyline plot suggested that a 1000-fold increase in population size occurred approximately 10,000 years before present, suggesting a species expansion after the Last Glacial Maximum.GAME from the National Science Centre, the Polish Ministry of Science and Higher Education Iuventus Plus [IP2014 050573]; FCT-PT [CCMAR/Multi/04326/2013]; [2011/03/B/NZ8/02876

Spatiotemporal maintenance of flora in the Himalaya biodiversity hotspot:Current knowledge and future perspectives

Mountain ecosystems support a significant one‐third of all terrestrial biodiversity, but our understanding of the spatiotemporal maintenance of this high biodiversity remains poor, or at best controversial. The Himalaya hosts a complex mountain ecosystem with high topographic and climatic heterogeneity and harbors one of the world's richest floras. The high species endemism, together with increasing anthropogenic threats, has qualified the Himalaya as one of the most significant global biodiversity hotspots. The topographic and climatic complexity of the Himalaya makes it an ideal natural laboratory for studying the mechanisms of floral exchange, diversification, and spatiotemporal distributions. Here, we review literature pertaining to the Himalaya in order to generate a concise synthesis of the origin, distribution, and climate change responses of the Himalayan flora. We found that the Himalaya supports a rich biodiversity and that the Hengduan Mountains supplied the majority of the Himalayan floral elements, which subsequently diversified from the late Miocene onward, to create today's relatively high endemicity in the Himalaya. Further, we uncover links between this Miocene diversification and the joint effect of geological and climatic upheavals in the Himalaya. There is marked variance regarding species dispersal, elevational gradients, and impact of climate change among plant species in the Himalaya, and our review highlights some of the general trends and recent advances on these aspects. Finally, we provide some recommendations for conservation planning and future research. Our work could be useful in guiding future research in this important ecosystem and will also provide new insights into the maintenance mechanisms underpinning other mountain systems

A realist evaluation of the role of communities of practice in changing healthcare practice

<p>Abstract</p> <p>Background</p> <p>Healthcare organisations seeking to manage knowledge and improve organisational performance are increasingly investing in communities of practice (CoPs). Such investments are being made in the absence of empirical evidence demonstrating the impact of CoPs in improving the delivery of healthcare. A realist evaluation is proposed to address this knowledge gap. Underpinned by the principle that outcomes are determined by the context in which an intervention is implemented, a realist evaluation is well suited to understand the role of CoPs in improving healthcare practice. By applying a realist approach, this study will explore the following questions: What outcomes do CoPs achieve in healthcare? Do these outcomes translate into improved practice in healthcare? What are the contexts and mechanisms by which CoPs improve healthcare?</p> <p>Methods</p> <p>The realist evaluation will be conducted by developing, testing, and refining theories on how, why, and when CoPs improve healthcare practice. When collecting data, context will be defined as the setting in which the CoP operates; mechanisms will be the factors and resources that the community offers to influence a change in behaviour or action; and outcomes will be defined as a change in behaviour or work practice that occurs as a result of accessing resources provided by the CoP.</p> <p>Discussion</p> <p>Realist evaluation is being used increasingly to study social interventions where context plays an important role in determining outcomes. This study further enhances the value of realist evaluations by incorporating a social network analysis component to quantify the structural context associated with CoPs. By identifying key mechanisms and contexts that optimise the effectiveness of CoPs, this study will contribute to creating a framework that will guide future establishment and evaluation of CoPs in healthcare.</p

Biomarkers of cardiovascular risk across phenotypes of osteoarthritis

Abstract: Background: The objective of this study was to explore the associations between ultrasonographic and radiographic joint scores and levels of arterial CVD risk markers in patients with osteoarthritis (OA). Secondly, to compare the levels of arterial CVD risk markers between OA phenotypes and controls. Method: The “Musculoskeletal pain in Ullensaker” Study (MUST) invited residents of Ullensaker municipality with self-reported OA to a medical examination. OA was defined according to the American College of Rheumatology (ACR) criteria and phenotyped based on joint distribution. Joints of the hands, hips and knees were examined by ultrasonography and conventional radiography, and scored for osteosteophytes. Hands were also scored for inflammation by grey scale (GS) synovitis and power Doppler (PD) signal. Control populations were a cohort of inhabitants of Oslo (OCP), and for external validation, a UK community-based register (UKPC). Pulse pressure augmentation index (AIx) and pulse wave velocity (PWV) were measured using the Sphygmocor apparatus (Atcor®). Ankel-brachial index (ABI) was estimated in a subset of patients. In separate adjusted regression models we explored the associations between ultrasonography and radiograph joint scores and AIx, PWV and ABI. CVD risk markers were also compared between phenotypes of OA and controls in adjusted analyses. Results: Three hundred and sixty six persons with OA were included (mean age (range); 63.0 (42.0–75.0)), (females (%); 264 (72)). Of these, 155 (42.3%) had isolated hand OA, 111 (30.3%) had isolated lower limb OA and 100 (27.3%) had generalized OA. 108 persons were included in the OCP and 963 persons in the UKPC; (mean age (range); OCP: 57.2 (40.4–70.4), UKPC: 63.9 (40.0–75.0), females (%); OCP: 47 (43.5), UKPC: 543 (56.4%). Hand osteophytes were associated with AIx while GS and PD scores were not related to CVD risk markers. All OA phenotypes had higher levels of AIx compared to OCP in adjusted analyses. External validation against UKPC confirmed these findings. Conclusions: Hand osteophytes might be related to higher risk of CVD. People with OA had higher augmented central pressure compared to controls. Words 330