13,350 research outputs found
Violation of the London Law and Onsager-Feynman quantization in multicomponent superconductors
Non-classical response to rotation is a hallmark of quantum ordered states
such as superconductors and superfluids. The rotational responses of all
currently known single-component "super" states of matter (superconductors,
superfluids and supersolids) are largely described by two fundamental
principles and fall into two categories according to whether the systems are
composed of charged or neutral particles: the London law relating the angular
velocity to a subsequently established magnetic field and the Onsager-Feynman
quantization of superfluid velocity. These laws are theoretically shown to be
violated in a two-component superconductor such as the projected liquid
metallic states of hydrogen and deuterium at high pressures. The rotational
responses of liquid metallic hydrogen or deuterium identify them as a new class
of dissipationless states; they also directly point to a particular
experimental route for verification of their existence.Comment: Nature Physics in print. This is an early version of the paper. The
final version will be posted 6 months after its publication Nature Physics,
according to the journal polic
A global assessment of the impact of climate change on water scarcity
This paper presents a global scale assessment of the impact of climate change on water scarcity. Patterns of climate change from 21 Global Climate Models (GCMs) under four SRES scenarios are applied to a global hydrological model to estimate water resources across 1339 watersheds. The Water Crowding Index (WCI) and the Water Stress Index (WSI) are used to calculate exposure to increases and decreases in global water scarcity due to climate change. 1.6 (WCI) and 2.4 (WSI) billion people are estimated to be currently living within watersheds exposed to water scarcity. Using the WCI, by 2050 under the A1B scenario, 0.5 to 3.1 billion people are exposed to an increase in water scarcity due to climate change (range across 21 GCMs). This represents a higher upper-estimate than previous assessments because scenarios are constructed from a wider range of GCMs. A substantial proportion of the uncertainty in the global-scale effect of climate change on water scarcity is due to uncertainty in the estimates for South Asia and East Asia. Sensitivity to the WCI and WSI thresholds that define water scarcity can be comparable to the sensitivity to climate change pattern. More of the world will see an increase in exposure to water scarcity than a decrease due to climate change but this is not consistent across all climate change patterns. Additionally, investigation of the effects of a set of prescribed global mean temperature change scenarios show rapid increases in water scarcity due to climate change across many regions of the globe, up to 2°C, followed by stabilisation to 4°C
Heterogeneity in clinical features and disease severity in ataxia-associated SYNE1 mutations
The autosomal recessive spinocerebellar ataxias are an exciting field of study, with a growing number of causal genes and an expanding phenotypic spectrum. SYNE1 was originally discovered in 2007 as the causal gene underlying autosomal recessive spinocerebellar ataxia 1, a disease clinically thought to manifest with mainly pure cerebellar ataxia. Since the original report SYNE1 mutations have also been identified in families with motor neuronopathy and arthrogryposis but few families have been screened as the gene is very large at 146 exons in length. We screened 196 recessive and sporadic ataxia patients for mutations in SYNE1 using next generation sequencing in order to assess its frequency and extend the clinicogenetic spectrum. We identified four novel truncating mutations spread throughout the SYNE1 gene from three families living in London that originated from England, Turkey and Sri Lanka. The phenotype was mainly pure cerebellar ataxia in two families, cognitive decline was present in all three families, axonal neuropathy in one family and marked spasticity in the Turkish family, with a range of disease severities. Searching for genotype-phenotype correlations in the SYNE1 gene, defects located near the 3' prime end of the gene are more frequently associated with motor neuron or neuromuscular involvement so far. Our data indicate SYNE1 mutations are not an uncommon cause of recessive ataxia with or without additional clinical features in patients from various ethnicities. The use of next generation sequencing allows the rapid analysis of large genes and will likely reveal more SYNE1 associated cases and further expand genotype-phenotype correlations
Splitting It Up: The spduration Split-Population Duration Regression Package for Time-Varying Covariates
We present an implementation of split-population duration regression in the spduration
(Beger et al., 2017) package for R that allows for time-varying covariates. The statistical model accounts
for units that are immune to a certain outcome and are not part of the duration process the researcher
is primarily interested in. We provide insights for when immune units exist, that can significantly
increase the predictive performance compared to standard duration models. The package includes
estimation and several post-estimation methods for split-populationWeibull and log-logistic models.
We provide an empirical application to data on military coups
Non-randomised comparison of acute and long-term outcomes of robotic versus manual ventricular tachycardia ablation in a single centre ischemic cohort.
Firewall? or Wall on Fire? A Unified Framework of Conflict Contagion and the Role of Ethnic Exclusion
While some borders are real firewalls against conflicts, others appear like tinder just waiting for the smallest spark. Only recently has research focused on the transnational perspective of conflict and current research has focused mostly on isolated aspects of this phenomenon. In this article, we provide a unified framework for conflict contagion that takes into account receiver, sender, dyad, and network effects. This is a novel perspective on conflict contagion, and our empirical results suggest that distinguishing between sender and receiver effects allows for a better understanding of spillover effects. We provide insights that especially excluded ethnic groups impact the risk of countries sending and receiving conflicts from its neighbors
Experimental observation of moving intrinsic localized modes in germanium
Deep level transient spectroscopy shows that defects created by alpha
irradiation of germanium are annealed by low energy plasma ions up to a depth
of several thousand lattice units. The plasma ions have energies of 2-8eV and
therefore can deliver energies of the order of a few eV to the germanium atoms.
The most abundant defect is identified as the E-center, a complex of the dopant
antimony and a vacancy with and annealing energy of 1.3eV as determined by our
measurements. The inductively coupled plasma has a very low density and a very
low flux of ions. This implies that the ion impacts are almost isolated both in
time and at the surface of the semiconductor. We conclude that energy of the
order of an eV is able to travel a large distance in germanium in a localized
way and is delivered to the defects effectively. The most likely candidates are
vibrational nonlinear wave packets known as intrinsic localized modes, which
exist for a limited range of energies. This property is coherent with the fact
that more energetic ions are less efficient at producing the annealing effect.Comment: 20 pages, 10 figure
Strategi Pengembangan Agribisnis Peternakan Ayam Petelur di Kabupaten Tabanan
Agribusiness is one sector which is based on farm business or the other fields that support it. Activity in the agribusiness sector includs any one or all of the chain along production, processing and marketing including poultry farm. This study aims to determine how the layer farmers profile, strategic internal factors (strengths and weaknesses) and external (opportunities and challenges) affecting farm poultry as well as the development of alternative strategies and what strategies are feasible priority. Respondents were termined using a proportional random sampling of layer farmers in Tabanan regency. Internal and external factors evaluated by the IFE matrix and EFE matrix. Alternative defined strategy with IE matrix and SWOT matrix, and for the determination of strategic priorities determined by matrix QSPM. The results showed that the internal factors are a major force in the development of poultry farm is a hereditary business and the availability of means of transport. Externally, the main factor being the availability of market opportunities and short distribution and population growth. Factors are the main challenges and the fluctuating price of chicken diseases. Main strategy (grand strategy) for poultry farm agribusiness development is market penetration and product development. Market penetration strategy is a strategy used to increase market share of the product or service through marketing efforts greater. Product development strategy is a strategy that aims to make companies that partnered to increase sales by improving or modifying existing products now. Alternative strategy is to increase market share to achieve the position of market leader through a policy of local governments and related enterprises, control and surveillance of pests or diseases of livestock farm in order to be sustainable, the capital guarantee and optimize field officers, and optimize working capital and increase ability in the development of an efficient agribusiness. Strategic priorities poultry farm agribusiness development is a strategy to achieve increased market share market leader position through policies of local governments and related companies
- …
