X-type and Y-type junction stability in domain wall networks

We develop an analytic formalism that allows one to quantify the stability properties of X-type and Y-type junctions in domain wall networks in two dimensions. A similar approach might be applicable to more general defect systems involving junctions that appear in a range of physical situations, for example, in the context of F- and D-type strings in string theory. We apply this formalism to a particular field theory, Carter's pentavac model, where the strength of the symmetry breaking is governed by the parameter $|\epsilon|< 1$. We find that for low values of the symmetry breaking parameter X-type junctions will be stable, whereas for higher values an X-type junction will separate into two Y-type junctions. The critical angle separating the two regimes is given by \alpha_c = 293^{\circ}\sqrt{|\epsilon|} and this is confirmed using simple numerical experiments. We go on to simulate the pentavac model from random initial conditions and we find that the dominant junction is of \ytype for |\epsilon| \geq 0.02 and is of \xtype for |\epsilon| \leq 0.02$. We also find that for small$\epsilon$the evolution of the number of domain walls$\qsubrm{N}{dw}$in Minkowski space does not follow the standard$\propto t^{-1}$scaling law with the deviation from the standard lore being more pronounced as$\epsilon$is decreased. The presence of dissipation appears to restore the$t^{-1}$ lore.Comment: 24 pages, 13 figures; typos fixe

Diets of leaf litter-associated invertebrates in three tropical streams

Shredders play a major ecological role in temperate streams, but their numerical importance is highly variable within the tropics. Detailed studies on the diets of tropical stream invertebrates are advisable to be able to better describe and understand this variation. Here, we examined the diets of invertebrates collected from the leaf litter of three tropical streams in Colombia, using gut content analysis. Fine and coarse particulate organic matter were the main food resources for invertebrates, which could be divided into four main dietary groups: predators, shredders, specialist collectors and generalist collectors. While the specialist collectors were the most numerically abundant group (54%), shredder biomass accounted for 63% of total invertebrate biomass, suggesting that shredders play a significant ecological role in the study streams. We describe the diets of 12 out of 47 taxa that were previously unknown, which indicates that knowledge about the feeding ecology of tropical stream invertebrates is still incipient. © 2012 EDP Sciences.Peer Reviewe

Frequent expansion of Plasmodium vivax Duffy Binding Protein in Ethiopia and its epidemiological significance.

Plasmodium vivax invasion of human erythrocytes depends on the Duffy Binding Protein (PvDBP) which interacts with the Duffy antigen. PvDBP copy number has been recently shown to vary between P. vivax isolates in Sub-Saharan Africa. However, the extent of PvDBP copy number variation, the type of PvDBP multiplications, as well as its significance across broad samples are still unclear. We determined the prevalence and type of PvDBP duplications, as well as PvDBP copy number variation among 178 Ethiopian P. vivax isolates using a PCR-based diagnostic method, a novel quantitative real-time PCR assay and whole genome sequencing. For the 145 symptomatic samples, PvDBP duplications were detected in 95 isolates, of which 81 had the Cambodian and 14 Malagasy-type PvDBP duplications. PvDBP varied from 1 to &gt;4 copies. Isolates with multiple PvDBP copies were found to be higher in symptomatic than asymptomatic infections. For the 33 asymptomatic samples, PvDBP was detected with two copies in two of the isolates, and both were the Cambodian-type PvDBP duplication. PvDBP copy number in Duffy-negative heterozygotes was not significantly different from that in Duffy-positives, providing no support for the hypothesis that increased copy number is a specific association with Duffy-negativity, although the number of Duffy-negatives was small and further sampling is required to test this association thoroughly

Informationの多変数解析への応用について

The Paleocene–Eocene Thermal Maximum (PETM), at ca. 55.8 Ma, is one of the most studied instances of past greenhouse gas-induced global warming. As such, it provides a rich opportunity to examine the impact of such global change on local climates. The effects of increased continental and sea surface temperatures on local precipitation and humidity during the PETM remain poorly constrained and studies reveal complex, regional differences; whilst some localities appear to experience a net increase in humidity, others exhibit the opposite. Crucially, there are few records of hydrological change from tropical regions. Recent onshore drilling expeditions in Tanzania have yielded expanded sedimentary sections, deposited in a marine environment, that span much of the Late Cretaceous and Paleogene and show exceptionally good preservation of both calcareous microfossils and organic matter. The PETM interval has previously been constrained by both biostratigraphy and carbon isotopic records and spans ca. 7 m of section. Lipid distributions, including various terrestrial, marine and bacterial biomarkers and their hydrogen isotopic compositions, as well as mineralogy, were used to examine East African vegetation and hydrological responses to the global change occurring at the PETM. Although total organic carbon contents decrease, the concentrations of both higher plant (n-alkanes, n-alkanoic acids) and soil bacterial (glycerol dialkyl glycerol tetraethers) biomarkers increase dramatically at the onset of the PETM negative carbon isotope excursion (CIE), suggesting an increased discharge of fluvial sedimentary organic matter. Similarly, mineralogical indicators of terrestrial input – including Ti/Al and Si/Al ratios, quartz contents and, notably, the proportion of kaolinite – also increase at the onset of the CIE. However, higher plant leaf wax n-alkanes (C27, C29 and C31) become more deuterium-enriched throughout the same interval, suggesting a more arid and/or hotter, rather than a more humid, environment. This evidence collectively suggests an East African early PETM climate characterised by overall hot and arid conditions punctuated by intense, perhaps seasonal, precipitation events. These data match observations from other locations at mid-latitudes, suggesting that the humid climate often suggested for the PETM was not globally widespread

Risk of cardiovascular disease and total mortality in adults with type 1 diabetes: Scottish registry linkage study

&lt;p&gt;Background: Randomized controlled trials have shown the importance of tight glucose control in type 1 diabetes (T1DM), but few recent studies have evaluated the risk of cardiovascular disease (CVD) and all-cause mortality among adults with T1DM. We evaluated these risks in adults with T1DM compared with the non-diabetic population in a nationwide study from Scotland and examined control of CVD risk factors in those with T1DM.&lt;/p&gt; &lt;p&gt;Methods and Findings: The Scottish Care Information-Diabetes Collaboration database was used to identify all people registered with T1DM and aged ≥20 years in 2005–2007 and to provide risk factor data. Major CVD events and deaths were obtained from the national hospital admissions database and death register. The age-adjusted incidence rate ratio (IRR) for CVD and mortality in T1DM (n = 21,789) versus the non-diabetic population (3.96 million) was estimated using Poisson regression. The age-adjusted IRR for first CVD event associated with T1DM versus the non-diabetic population was higher in women (3.0: 95% CI 2.4–3.8, p&#60;0.001) than men (2.3: 2.0–2.7, p&#60;0.001) while the IRR for all-cause mortality associated with T1DM was comparable at 2.6 (2.2–3.0, p&#60;0.001) in men and 2.7 (2.2–3.4, p&#60;0.001) in women. Between 2005–2007, among individuals with T1DM, 34 of 123 deaths among 10,173 who were &#60;40 years and 37 of 907 deaths among 12,739 who were ≥40 years had an underlying cause of death of coma or diabetic ketoacidosis. Among individuals 60–69 years, approximately three extra deaths per 100 per year occurred among men with T1DM (28.51/1,000 person years at risk), and two per 100 per year for women (17.99/1,000 person years at risk). 28% of those with T1DM were current smokers, 13% achieved target HbA1c of &#60;7% and 37% had very poor (≥9%) glycaemic control. Among those aged ≥40, 37% had blood pressures above even conservative targets (≥140/90 mmHg) and 39% of those ≥40 years were not on a statin. Although many of these risk factors were comparable to those previously reported in other developed countries, CVD and mortality rates may not be generalizable to other countries. Limitations included lack of information on the specific insulin therapy used.&lt;/p&gt; &lt;p&gt;Conclusions: Although the relative risks for CVD and total mortality associated with T1DM in this population have declined relative to earlier studies, T1DM continues to be associated with higher CVD and death rates than the non-diabetic population. Risk factor management should be improved to further reduce risk but better treatment approaches for achieving good glycaemic control are badly needed.&lt;/p&gt

CMB observations from the CBI and VSA: A comparison of coincident maps and parameter estimation methods

We present coincident observations of the Cosmic Microwave Background (CMB) from the Very Small Array (VSA) and Cosmic Background Imager (CBI) telescopes. The consistency of the full datasets is tested in the map plane and the Fourier plane, prior to the usual compression of CMB data into flat bandpowers. Of the three mosaics observed by each group, two are found to be in excellent agreement. In the third mosaic, there is a 2 sigma discrepancy between the correlation of the data and the level expected from Monte Carlo simulations. This is shown to be consistent with increased phase calibration errors on VSA data during summer observations. We also consider the parameter estimation method of each group. The key difference is the use of the variance window function in place of the bandpower window function, an approximation used by the VSA group. A re-evaluation of the VSA parameter estimates, using bandpower windows, shows that the two methods yield consistent results.Comment: 10 pages, 6 figures. Final version. Accepted for publication in MNRA

Be outraged: there are alternatives

Pushed to extremes, austerity is bad economics, bad arithmetic, and ignores the lessons of history. We, an international group of economists and social scientists, are outraged at the narrow range of austerity policies which are bringing so many people around the world to their knees, especially in Europe. Austerity and cutbacks are reducing growth and worsening poverty. In our professional opinions, there are alternatives – for Britain, Europe and all countries that currently imagine that government cutbacks are the only way out of debt. The low-growth, no-growth trap means that the share of debt in GNP falls ever more slowly, if at all. It may even rise – as it has in some countries

Polarization and relaxation of radon

Investigations of the polarization and relaxation of $^{209}$Rn by spin exchange with laser optically pumped rubidium are reported. On the order of one million atoms per shot were collected in coated and uncoated glass cells. Gamma-ray anisotropies were measured as a signal of the alignment (second order moment of the polarization) resulting from the combination of polarization and quadrupole relaxation at the cell walls. The temperature dependence over the range 130$^\circ$C to 220$^\circ$C shows the anisotropies increasing with increasing temperature as the ratio of the spin exchange polarization rate to the wall relaxation rate increases faster than the rubidium polarization decreases. Polarization relaxation rates for coated and uncoated cells are presented. In addition, improved limits on the multipole mixing ratios of some of the main gamma-ray transitions have been extracted. These results are promising for electric dipole moment measurements of octupole-deformed $^{223}$Rn and other isotopes, provided sufficient quantities of the rare isotopes can be produced.Comment: 4 pages, 4 figure