Disorder and interactions in quantum Hall ferromagnets: effects of disorder in Skyrmion physics

We present a Hartree-Fock study of the competition between disorder and interactions in quantum Hall ferromagnets near $\nu=1$. We find that the ground state at $\nu=1$ evolves with increasing interaction strength from a quasi-metallic paramagnet, to a partially spin-polarized ferromagnetic Anderson insulator, and to a fully spin-polarized ferromagnet with a charge gap. Away from $\nu=1$, the ground state evolves from a conventional Anderson insulator, to a conventional quasiparticle glass, and finally to a ferromagnetic Skyrmion quasiparticle glass. These different regimes can be measured in low-temperature transport and NMR experiments. We present calculations for the NMR spectra in different disorder regimes.Comment: 3 pages, 3 figures, proceedings for EP2DS-14, Prague 200

In silico analysis of sequenced strains of Clostridium difficile reveals a related set of conjugative transposons carrying a variety of accessory genes

The human gut pathogen Clostridium difficile contains many conjugative transposons that have an array of accessory genes. In the current study, recently sequenced genomes were analyzed to identify new putative conjugative transposons. Eleven new elements in 5 C. difficile strains were identified and all had a similar structure to the previously described elements CTn1, CTn5 and CTn7 in C. difficile strain 630. Each element identified did however contain a new set of accessory genes compared with those previously reported; including those predicted to encode ABC transporters, a toxin/antitoxin system and multiple antibiotic resistance genes

Screening versus routine practice in detection of atrial fibrillation in patients aged 65 or over: Screening versus routine practice in detection cluster randomised controlled trial

Objectives : To assess whether screening improves the detection of atrial fibrillation (cluster randomisation) and to compare systematic and opportunistic screening. Design : Multicentred cluster randomised controlled trial, with subsidiary trial embedded within the intervention arm. Setting : 50 primary care centres in England, with further individual randomisation of patients in the intervention practices. Participants : 14,802 patients aged 65 or over in 25 intervention and 25 control practices. Interventions : Patients in intervention practices were randomly allocated to systematic screening (invitation for electrocardiography) or opportunistic screening (pulse taking and invitation for electrocardiography if the pulse was irregular). Screening took place over 12 months in each practice from October 2001 to February 2003. No active screening took place in control practices. Main outcome measure : Newly identified atrial fibrillation. Results : The detection rate of new cases of atrial fibrillation was 1.63% a year in the intervention practices and 1.04% in control practices (difference 0.59%, 95% confidence interval 0.20% to 0.98%). Systematic and opportunistic screening detected similar numbers of new cases (1.62% v 1.64%, difference 0.02%, −0.5% to 0.5%). Conclusion : Active screening for atrial fibrillation detects additional cases over current practice. The preferred method of screening in patients aged 65 or over in primary care is opportunistic pulse taking with follow-up electrocardiography. Trial registration Current Controlled Trials ISRCTN19633732

Decreased Haemodynamic Response and Decoupling of Cortical Gamma Band Activity and Tissue Oxygen Perfusion after Striatal Interleukin-1 Injection.

Background: Neurovascular coupling describes the mechanism by which the energy and oxygen demand arising from neuronal activity is met by an increase in regional blood flow; known as the haemodynamic response. Interleukin 1 (IL-1) is a pro-inflammatory cytokine and an important mediator of neuronal injury, though mechanisms through which IL-1 exerts its effects in the brain are not fully understood. In this study we set out to investigate if increased cerebral levels of IL-1 have a negative effect on neurovascular coupling in the cortex in response to sensory stimulation. Methods: We used two approaches to measure the neuronal activity and haemodynamic changes in the anaesthetised rat barrel somatosensory cortex in response to mechanical whisker stimulation, before and for 6 h after intrastriatal injection of interleukin-1β or vehicle. First, we used two dimensional optical imaging spectroscopy (2D-OIS) to measure the size of the functional haemodynamic response, indicated by changes of oxyhaemoglobin (HbO2) and total haemoglobin (HbT) concentration. In the same animals immunostaining of immunoglobulin G and SJC-positive extravasated neutrophils was used to confirm the pro-inflammatory effects of IL-1β. Second, to examine the functional coupling between neuronal activity and the haemodynamic response, we used a ‘Clark-style’ electrode combined with a single sharp electrode to simultaneously record local tissue oxygenation (pO2) in layer IV/V of the stimulated barrel cortex and multi-unit activity (MUA) together with local field potentials (LFPs) respectively. Results: 2D-OIS data revealed that the size of the haemodynamic response to mechanical whisker stimulation declined over the 6 h following IL-1β injection whereas the vehicle group remained stable, significant differences being seen after 5 h. Moreover, the size of the transient increases of neuronal LFP activity in response to whisker stimulation decreased after IL-1β injection, significant changes compared to vehicle being seen for gamma-band activity after 1 h and beta-bandactivity after 3 h. The amplitude of the functional pO2 response similarly decreased after 3 h post IL-1β injection, whereas IL-1β had no significant effect on the peak of whisker-stimulation-induced MUA. The stimulation-evoked increases in gamma power and pO2 correlated significantly throughout the 6 h in the vehicle group, but such a correlation was not observed in the IL-1β-injected group. Conclusions: We conclude that intrastriatal IL-1β decouples cortical neuronal activity from its haemodynamic response. This finding may have implications for neurological conditions where IL-1β plays a part, especially those involving reductions in cerebral blood flow (such as stroke)

Anomalous mid-twentieth century atmospheric circulation change over the South Atlantic compared to the last 6000 years

Determining the timing and impact of anthropogenic climate change in data-sparse regions is a considerable challenge. Arguably, nowhere is this more difficult than the Antarctic Peninsula and the subantarctic South Atlantic where observational records are relatively short but where high rates of warming have been experienced since records began. Here we interrogate recently developed monthly-resolved observational datasets from the Falkland Islands and South Georgia, and extend the records back using climate-sensitive peat growth over the past 6000 years. Investigating the subantarctic climate data with ERA-Interim and Twentieth Century Reanalysis, we find that a stepped increase in precipitation across the 1940s is related to a change in synoptic atmospheric circulation: a westward migration of quasi-permanent positive pressure anomalies in the South Atlantic has brought the subantarctic islands under the increased influence of meridional airflow associated with the Amundsen Sea Low. Analysis of three comprehensively multi-dated (using 14C and 137Cs) peat sequences across the two islands demonstrates unprecedented growth rates since the mid-twentieth century relative to the last 6000 years. Comparison to observational and reconstructed sea surface temperatures suggests this change is linked to a warming tropical Pacific Ocean. Our results imply 'modern' South Atlantic atmospheric circulation has not been under this configuration for millennia

Association between statin use after diagnosis of esophageal cancer and survival: a population-based cohort study

Background & Aims: Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors), commonly prescribed to prevent cardiovascular disease, promote apoptosis and limit proliferation of esophageal cancer cell lines. We investigated whether statin use following diagnosis of esophageal cancer is associated with reduced esophageal cancer-specific and all-cause mortality.  Methods: We identified a cohort of 4445 men and women in the United Kingdom diagnosed with esophageal cancer from January 2000 through November 2009 using the General Practice Research Database. The National Cancer Registry and Office of National Statistics datasets respectively established the histologic subtype and cancer-specific mortality. Cox proportional hazard regression analysis with time-dependent exposures estimated the association between statin use after diagnosis and esophageal cancer-specific and all-cause mortality.  Results: The median survival time of the entire cohort was 9.2 months (inter-quartile range [IQR], 3.7–23.2 months). Among subjects who used statins after diagnosis of esophageal cancer, the median survival time was 14.9 months (IQR, 7.1–52.3) compared to 8.1 months for non-users (IQR, 3.3–20). In the entire cohort, statin use after diagnosis was associated with a decreased risk of esophageal cancer-specific mortality (adjusted hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.44–0.86) and all-cause mortality (HR, 0.67; 95% CI, 0.58–0.77). In patients with esophageal adenocarcinoma, statin use after diagnosis was associated with decreased risk of esophageal cancer-specific mortality (HR, 0.61; 95% CI 0.38–0.96) and all-cause mortality (HR, 0.63; 95% 0.43–0.92). This effect was not observed in patients with esophageal squamous cell carcinoma. There was no evidence for effect modification of these associations with statin use before cancer diagnosis.  Conclusions: In a large population-based cohort, statin use after diagnosis of esophageal adenocarcinoma, but not esophageal squamous cell carcinoma, was associated with reduced esophageal cancer-specific and all-cause mortality

Flow characteristics of Newtonian and non-Newtonian fluids in a vessel stirred by a 60° pitched blade impeller

Mean and rms velocity characteristics of two Newtonian flows at Reynolds numbers of 12,800 (glycerin solution) and 48,000 (water) and of a non-Newtonian flow (0.2% CMC solution, at a power number similar to the Newtonian glycerin flow) in a mixing vessel stirred by a 60° pitched blade impeller have been measured by laser Doppler velocimetry (LDV). The velocity measurements, resolved over 360° and 1.08° of impeller rotation, showed that the mean flow of the two power number matched glycerin and CMC flows were similar to within 3% of the impeller tip velocity and the turbulence intensities generally lower in the CMC flow by up to 5% of the tip velocity. The calculated mean flow quantities showed similar discharge coefficient and pumping efficiency in all three flows and similar strain rate between the two power number matched glycerin and CMC flows; the strain rate of the higher Reynolds number Newtonian flow was found to be slightly higher. The energy balance around the impeller indicated that the CMC flow dissipated up to 9% more of the total input power and converted 7% less into the turbulence compared to the glycerin flow with the same power input which could lead to less effective mixing processes where the micro-mixing is important

The complex and spatially diverse patterns of hydrological droughts across Europe

This study presents a new data set of gauged streamflow (N = 3,224) for Europe spanning the period 1962–2017. The Monthly Streamflow of Europe Dataset (MSED) is freely available at http://msed.csic.es/. Based on this data set, changes in the characteristics of hydrological drought (i.e., frequency, duration, and severity) were assessed for different regions of Europe. Due to the density of the database, it is possible to delimit spatial patterns in hydrological droughts trend with the greatest detail available to date. Results reveal bidirectional changes in monthly streamflow, with negative changes predominating over central and southern Europe, while positive trends dominate over northern Europe. Temporally, two dominant patterns were noted. The first pattern corresponds to a consistent downward trend in all months, evident for southern Europe. A second pattern was noted over central and northern Europe and western France, with a predominant negative trend during warm months and a positive trend in cold months. For hydrological drought events, results suggest a positive trend toward more frequent and severe droughts in southern and central Europe and conversely a negative trend over northern Europe. This study emphasizes that hydrological droughts show complex spatial patterns across Europe over the past six decades, implying that hydrological drought behavior in Europe has a regional character. Accordingly it is challenging to adopt “efficient” strategies and policies to monitor and mitigate drought impacts at the continental level

The New Political History

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66569/2/10.1177_000276427702100204.pd