Energy Dissipation and Regularity for a Coupled Navier-Stokes and Q-Tensor System

We study a complex non-newtonian fluid that models the flow of nematic liquid crystals. The fluid is described by a system that couples a forced Navier-Stokes system with a parabolic-type system. We prove the existence of global weak solutions in dimensions two and three. We show the existence of a Lyapunov functional for the smooth solutions of the coupled system and use the cancellations that allow its existence to prove higher global regularity, in dimension two. We also show the weak-strong uniqueness in dimension two

Quantum tunneling on graphs

We explore the tunneling behavior of a quantum particle on a finite graph, in the presence of an asymptotically large potential. Surprisingly the behavior is governed by the local symmetry of the graph around the wells.Comment: 18 page

High-resolution UV spectrum of the benzene—N2 van der Waals complex

The rotationally resolved spectrum of the 610 band of the S1 ← S0 electronic transition of the benzene—N2 van der Waals complex has been recorded and 119 transitions assigned. The C6H6·N2 complex, produced in a pulsed molecular beam, was detected by mass-selected two-photon two-colour ionization employing a high-resolution (ΔνUV = 100 MHz, fwhm) pulsed-amplified cw laser for the resonant intermediate excitation. The observed rotational structure is that of a rigid symmetric top with weaker additional rotational transitions most likely arising from the free internal rotation of the N2 in the plane parallel to the benzene ring. The N2 is located parallel to the benzene ring at a distance of 3.50 Å; this decreases by 45 mÅ in the excited electronic state

Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass

In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ~20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ~10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94 GeV^{+55%}_{-33%} for background-free data sets).Comment: 27 pages, 22 eps figures; v2: revised version for publication, references added and update

Longitudinal study of short‐term corticosteroid use by working‐age adults with diabetes mellitus: Risks and mitigating factors

BackgroundThis study assessed the frequency of short‐term oral corticosteroid use in adults with diabetes, examined the incidence of fractures, venous thromboembolism (VTE), and hospitalization for sepsis after corticosteroid use, and evaluated whether preventative medications mitigated adverse events.MethodsA longitudinal study (2012–14) was conducted of 1 548 945 adults (aged 18–64 years) who received healthcare coverage through a large national health insurer. Incidence rate ratios (IRR) were calculated using conditional Poisson regression.ResultsShort‐term oral corticosteroids were used by 23.9%, 20.8%, and 20.9% of adults with type 2 diabetes, type 1 diabetes, and no diabetes, respectively, during the 3‐year period (P < 0.001). Baseline risks of fracture, VTE, and sepsis were greater for individuals with than without diabetes (P < 0.001). The combined effect of having diabetes and using corticosteroids was greater than the sum of the individual effects (synergy indices of 1.17, 1.23, 1.30 for fracture, VTE, and sepsis, respectively). The IRR for VTE in the 5–30 days after corticosteroid use was 3.62 (95% confidence interval [CI] 2.41–5.45). Fractures increased in the 5–30 days after corticosteroid use (IRR 2.06; 95% CI 1.52, 2.80), but concomitant use of ergocalciferol mitigated this risk (IRR 1.13; 95% CI 0.12, 11.07). The risk of hospitalization for sepsis was elevated with corticosteroid use (IRR 3.79; 95% CI 2.05, 7.01), but was mitigated by the concomitant use of statins.ConclusionsShort‐term oral corticosteroid use is common in adults with diabetes and is associated with an elevated, but low, risk of adverse events. The findings suggest that preventative medications may mitigate risk.摘要背景这项研究在成年糖尿病患者中评估了短期使用口服糖皮质激素的频率,  调查了使用糖皮质激素后骨折与静脉血栓栓塞(venous thromboembolism, VTE)的发生率以及脓毒症的住院率,  并且评估了预防性用药是否会减少不良事件。方法这是一项在1548945名具有大型国家健康保险公司医疗保险的成年(年龄为18‐64岁)患者中进行的纵向研究(2012‐14)。使用有条件的Poisson回归分析来计算发病率比(incidence rate ratios, IRR)。结果在这3年期间,  短期使用口服糖皮质激素治疗的2型糖尿病、1型糖尿病以及非糖尿病成年患者的比例分别为23.9%、20.8%与20.9%(P < 0.001)。与非糖尿病患者相比,  糖尿病患者基线时的骨折、VTE以及脓毒症的风险都更高(P < 0.001)。患糖尿病以及使用糖皮质激素的联合效应大于个体效应之和(骨折、VTE以及脓毒症的协同指数分别为1.17、1.23、1.30)。使用糖皮质激素后的5‐30日内发生VTE的IRR为3.62(95%置信区间[CI]为2.41‐5.45)。使用糖皮质激素后的5‐30日内发生骨折的风险增加(IRR为2.06;95% CI为1.52, 2.80),  但同时使用麦角骨化醇治疗可以减少这种风险(IRR为1.13;95% CI为0.12, 11.07)。使用糖皮质激素后脓毒症的住院风险也增加了(IRR为3.79;95% CI为2.05, 7.01),  但是同时使用他汀类药物治疗可以减少这种风险。结论成年糖尿病患者短期使用口服糖皮质激素治疗很常见并且与不良事件风险轻度升高有关。这项研究结果表明预防性用药可以减少这种风险。HighlightsAdults with diabetes mellitus have a greater risk of fracture, venous thromboembolism, and sepsis than those without diabetes; the use of corticosteroids, even for short durations, increases this risk.Vitamin D mitigated the risk of fracture in patients with diabetes who used corticosteroids, and statins decreased the likelihood of hospitalization for sepsis in corticosteroid users with diabetes.Corticosteroids should be used with caution in patients with diabetes and mitigating factors should be considered.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144644/1/jdb12631.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144644/2/jdb12631_am.pd

RHESSI Results -- Time For a Rethink?

Hard X-rays and gamma-rays are the most direct signatures of energetic electrons and ions in the sun's atmosphere which is optically thin at these energies and their radiation involves no coherent processes. Being collisional they are complementary to gyro-radiation in probing atmospheric density as opposed to magnetic field and the electrons are primarily 10--100 keV in energy, complementing the (>100 keV) electrons likely responsible for microwave bursts. The pioneering results of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are raising the first new major questions concerning solar energetic particles in many years. Some highlights of these results are discussed -- primarily around RHESSI topics on which the authors have had direct research involvement -- particularly when they are raising the need for re-thinking of entrenched ideas. Results and issues are broadly divided into discoveries in the spatial, temporal and spectral domains, with the main emphasis on flare hard X-rays/fast electrons but touching also on gamma-rays/ions, non-flare emissions, and the relationship to radio bursts.Comment: Proceedings CESRA Workshop 2004: "The High Energy Solar Corona: Waves, Eruptions, Particles", Lecture Notes in Physics, 2006 (accepted

Teachers' classroom feedback: still trying to get it right

This article examines feedback traditionally given by teachers in schools. Such feedback tends to focus on children's acquisition and retrieval of externally prescribed knowledge which is then assessed against mandated tests. It suggests that, from a sociocultural learning perspective, feedback directed towards such objectives may limit children's social development. In this article, I draw on observation and interview data gathered from a group of 27 9- to 10-year olds in a UK primary school. These data illustrate the children's perceived need to conform to, rather than negotiate, the teacher's feedback comments. They highlight the children's sense that the teacher's feedback relates to school learning but not to their own interests. The article also includes alternative examples of feedback which draw on children's own inquiries and which relate to the social contexts within which, and for whom, they act. It concludes by suggesting that instead of looking for the right answer to the question of what makes teachers' feedback effective in our current classrooms, a more productive question might be how a negotiation can be opened up among teachers and learners themselves, about how teachers' feedback could support children's learning most appropriately

Hybrid meson decay from the lattice

We discuss the allowed decays of a hybrid meson in the heavy quark limit. We deduce that an important decay will be into a heavy quark non-hybrid state and a light quark meson, in other words, the de-excitation of an excited gluonic string by emission of a light quark-antiquark pair. We discuss the study of hadronic decays from the lattice in the heavy quark limit and apply this approach to explore the transitions from a spin-exotic hybrid to $\chi_b \eta$ and $\chi_b S$ where $S$ is a scalar meson. We obtain a signal for the transition emitting a scalar meson and we discuss the phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure

Necrotising Fasciitis of the Lower Limb caused by Community-Acquired Methicillin-Resistant Staphylococcus aureus

Necrotising fasciitis caused by Community-Acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a new entity. Although it is recognised worldwide, there have been no reported cases to date in Malaysia. We report a case of necrotising fasciitis of the left lower limb in an otherwise healthy 20-year-old man. He presented with septic shock and despite the paucity of clinical signs in the limb, the infection was aggressive. Methicillin-Resistant Staphylococcus aureus (MRSA) was isolated from the deep fascia of the leg. Panton-Valentine leucocidin gene (PVL), which is a stable genetic marker for CA-MRSA strain, was positive in this case. This case of community acquired MRSA necrotising fasciitis is of concern and may herald the emergence of this resistant organism in Malaysia. Vigilant surveillance and microbiological monitoring is needed to follow this CAMRSA trend