Theory of spin and lattice wave dynamics excited by focused laser pulses

We develop a theory of the spin wave dynamics excited by ultrafast focused laser pulses in a magnetic film. We take into account both volume and surface spin wave modes in the presence of applied, dipolar and magnetic anisotropy fields and include the dependence on laser spot exposure size and magnetic damping. We show that the sound waves generated by local heating by an ultrafast focused laser pulse can excite a wide spectrum of spin waves (on top of a dominant magnon-phonon contribution). Good agreement with recent experiments supports the validity of the model.Comment: 7 pages, 5 figure

Group Judgment and Decision Making in Auditing: Research in the Time of COVID-19 and Beyond

The COVID-19 pandemic has fundamentally changed how auditors work and interact with team members and others in the financial reporting process. In particular, there has been a move away from face-to-face interactions to the use of virtual teams, with strong indications many of these changes will remain post-pandemic. We examine the impacts of the pandemic on group judgment and decision making (JDM) research in auditing by reviewing research on auditor interactions with respect to the review process (including coaching), fraud brainstorming, consultations within audit firms, and parties outside the audit firm such as client management and the audit committee. Through the pandemic lens and for each auditor interaction, we consider new research questions for audit JDM researchers to investigate and new ways of addressing existing research questions given these fundamental changes. We also identify potential impacts on research methods used to address these questions during the pandemic and beyond

Diversity of felodipine solvates: Structure and physicochemical properties

Solvates of the calcium-channel blocking agent felodipine with three structurally related common organic solvents, acetone (ATN), dimethyl sulfoxide (DMSO) and acetophenone (APN), are described. A relationship between the felodipine packing arrangement in all known solvates and the van der Waals volume of the solvent molecule is established. Intermolecular interaction energies in the crystals are examined using the PIXEL approach in order to rationalize the difference between alternative molecule packing arrangements. DSC studies show that the desolvation onset temperatures of the solvates are closely comparable, despite the large difference in the boiling points of the solvent molecules. The enthalpies of formation derived from the calorimetric data for the solvates are also found to be similar, despite the difference in the van der Waals volume of the solvent molecules.This work was supported by a grant from the President of the Russian Federation no. МК- 67.2014.3 and Russian Foundation for Basic Research (project № 14-03-31001).This is the accepted manuscript. The final version is available at http://pubs.rsc.org/en/Content/ArticleLanding/2015/CE/C5CE00350D#!divAbstract

Bone mineral as a drug-seeking moiety and a waste dump

Bone is a dynamic tissue with a quarter of the trabecular and a fifth of the cortical bone being replaced continuously each year in a complex process that continues throughout an individual’s lifetime. Bone has an important role in homeostasis of minerals with non-stoichiometric hydroxyapatite bone mineral forming the inorganic phase of bone. Due to its crystal structure and chemistry, hydroxyapatite (HA) and related apatites have a remarkable ability to bind molecules. This review article describes the accretion of trace elements in bone mineral giving a historical perspective. Implanted HA particles of synthetic origin have proved to be an efficient recruiting moiety for systemically circulating drugs which can locally biomodulate the material and lead to a therapeutic effect. Bone mineral and apatite however also act as a waste dump for trace elements and drugs, which significantly affects the environment and human health

Quantification of the severity of hypoxic-ischemic brain injury in a neonatal preclinical model using measurements of cytochrome-c-oxidase from a miniature broadband-near-infrared spectroscopy system

We describe the development of a miniaturized broadband near-infrared spectroscopy system (bNIRS), which measures changes in cerebral tissue oxyhemoglobin (  [  HbO₂ ]  ) and deoxyhemoglobin ([HHb]) plus tissue metabolism via changes in the oxidation state of cytochrome-c-oxidase ([oxCCO]). The system is based on a small light source and a customized mini-spectrometer. We assessed the instrument in a preclinical study in 27 newborn piglets undergoing transient cerebral hypoxia-ischemia (HI). We aimed to quantify the recovery of the HI insult and estimate the severity of the injury. The recovery in brain oxygenation (Δ  [  HbDiff  ]    =  Δ  [  HbO₂  ]    −  Δ  [  HHb  ]  ), blood volume (Δ  [  HbT  ]    =  Δ  [  HbO₂  ]    +  Δ  [  HHb  ]  ), and metabolism (Δ  [  oxCCO  ]  ) for up to 30 min after the end of HI were quantified in percentages using the recovery fraction (RF) algorithm, which quantifies the recovery of a signal with respect to baseline. The receiver operating characteristic analysis was performed on bNIRS-RF measurements compared to proton (H1) magnetic resonance spectroscopic (MRS)-derived thalamic lactate/N-acetylaspartate (Lac/NAA) measured at 24-h post HI insult; Lac/NAA peak area ratio is an accurate surrogate marker of neurodevelopmental outcome in babies with neonatal HI encephalopathy. The Δ  [  oxCCO  ]  -RF cut-off threshold of 79% within 30 min of HI predicted injury severity based on Lac/NAA with high sensitivity (100%) and specificity (93%). A significant difference in thalamic Lac/NAA was noticed (p  <  0.0001) between the two groups based on this cut-off threshold of 79% Δ  [  oxCCO  ]  -RF. The severe injury group (n  =  13) had ∼30  %   smaller recovery in Δ  [  HbDiff  ]  -RF (p  =  0.0001) and no significant difference was observed in Δ  [  HbT  ]  -RF between groups. At 48 h post HI, significantly higher P31-MRS-measured inorganic phosphate/exchangeable phosphate pool (epp) (p  =  0.01) and reduced phosphocreatine/epp (p  =  0.003) were observed in the severe injury group indicating persistent cerebral energy depletion. Based on these results, the bNIRS measurement of the oxCCO recovery fraction offers a noninvasive real-time biomarker of brain injury severity within 30 min following HI insult

Clostridium difficile ribotypes in Austria: a multicenter, hospital-based survey

A prospective, noninterventional survey was conducted among Clostridium difficile positive patients identified in the time period of July until October 2012 in 18 hospitals distributed across all nine Austrian provinces. Participating hospitals were asked to send stool samples or isolates from ten successive patients with C.difficile infection to the National Clostridium difficile Reference Laboratory at the Austrian Agency for Health and Food Safety for PCR-ribotyping and in vitro susceptibility testing. A total of 171 eligible patients were identified, including 73 patients with toxin-positive stool specimens and 98 patients from which C. difficile isolates were provided. Of the 159 patients with known age, 127 (74.3 %) were 65 years or older, the median age was 76 years (range: 9–97 years), and the male to female ratio 2.2. Among these patients, 73 % had health care-associated and 20 % community-acquired C. difficile infection (indeterminable 7 %). The all-cause, 30-day mortality was 8.8 % (15/171). Stool samples yielded 46 different PCR-ribotypes, of which ribotypes 027 (20 %), 014 (15.8 %), 053 (10.5 %), 078 (5.3 %), and 002 (4.7 %) were the five most prevalent. Ribotype 027 was found only in the provinces Vienna, Burgenland, and Lower Austria. Severe outcome of C. difficile infection was found to be associated with ribotype 053 (prevalence ratio: 3.04; 95 % CI: 1.24, 7.44), not with the so-called hypervirulent ribotypes 027 and 078. All 027 and 053 isolates exhibited in vitro resistance against moxifloxacin. Fluoroquinolone use in the health care setting must be considered as a factor favoring the spread of these fluoroquinolone resistant C. difficile clones

The Beta Ansatz: A Tale of Two Complex Structures

Brane tilings, sometimes called dimer models, are a class of bipartite graphs on a torus which encode the gauge theory data of four-dimensional SCFTs dual to D3-branes probing toric Calabi-Yau threefolds. An efficient way of encoding this information exploits the theory of dessin d’enfants, expressing the structure in terms of a permutation triple, which is in turn related to a Belyi pair, namely a holomorphic map from a torus to a P1 with three marked points. The procedure of a-maximization, in the context of isoradial embeddings of the dimer, also associates a complex structure to the torus, determined by the R-charges in the SCFT, which can be compared with the Belyi complex structure. Algorithms for the explicit construction of the Belyi pairs are described in detail. In the case of orbifolds, these algorithms are related to the construction of covers of elliptic curves, which exploits the properties of Weierstraß elliptic functions. We present a counter example to a previous conjecture identifying the complex structure of the Belyi curve to the complex structure associated with R-charges

Risk stratification by pre-operative cardiopulmonary exercise testing improves outcomes following elective abdominal aortic aneurysm surgery : a cohort study

Background: In 2009, the NHS evidence adoption center and National Institute for Health and Care Excellence (NICE) published a review of the use of endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs). They recommended the development of a risk-assessment tool to help identify AAA patients with greater or lesser risk of operative mortality and to contribute to mortality prediction. A low anaerobic threshold (AT), which is a reliable, objective measure of pre-operative cardiorespiratory fitness, as determined by pre-operative cardiopulmonary exercise testing (CPET) is associated with poor surgical outcomes for major abdominal surgery. We aimed to assess the impact of a CPET-based risk-stratification strategy upon perioperative mortality, length of stay and non-operative costs for elective (open and endovascular) infra-renal AAA patients. Methods: A retrospective cohort study was undertaken. Pre-operative CPET-based selection for elective surgical intervention was introduced in 2007. An anonymized cohort of 230 consecutive infra-renal AAA patients (2007 to 2011) was studied. A historical control group of 128 consecutive infra-renal AAA patients (2003 to 2007) was identified for comparison. Comparative analysis of demographic and outcome data for CPET-pass (AT ≥ 11 ml/kg/min), CPET-fail (AT < 11 ml/kg/min) and CPET-submaximal (no AT generated) subgroups with control subjects was performed. Primary outcomes included 30-day mortality, survival and length of stay (LOS); secondary outcomes were non-operative inpatient costs. Results: Of 230 subjects, 188 underwent CPET: CPET-pass n = 131, CPET-fail n = 35 and CPET-submaximal n = 22. When compared to the controls, CPET-pass patients exhibited reduced median total LOS (10 vs 13 days for open surgery, n = 74, P < 0.01 and 4 vs 6 days for EVAR, n = 29, P < 0.05), intensive therapy unit requirement (3 vs 4 days for open repair only, P < 0.001), non-operative costs (£5,387 vs £9,634 for open repair, P < 0.001) and perioperative mortality (2.7% vs 12.6% (odds ratio: 0.19) for open repair only, P < 0.05). CPET-stratified (open/endovascular) patients exhibited a mid-term survival benefit (P < 0.05). Conclusion: In this retrospective cohort study, a pre-operative AT > 11 ml/kg/min was associated with reduced perioperative mortality (open cases only), LOS, survival and inpatient costs (open and endovascular repair) for elective infra-renal AAA surgery

Excitation of unidirectional exchange spin waves by a nanoscale magnetic grating

Magnon spintronics is a prosperous field that promises beyond-CMOS technology based on elementary excitations of the magnetic order that act as information carriers for future computational architectures. Unidirectional propagation of spin waves is key to the realization of magnonic logic devices. However, previous efforts to enhance the Damon-Eshbach-type nonreciprocity did not realize (let alone control) purely unidirectional propagation. Here we experimentally demonstrate excitations of unidirectional exchange spin waves by a nanoscale magnetic grating consisting of Co nanowires fabricated on an ultrathin yttrium iron garnet film. We explain and model the nearly perfect unidirectional excitation by the chirality of the magneto-dipolar interactions between the Kittel mode of the nanowires and the exchange spin waves of the film. Reversal of the magnetic configurations of film and nanowire array from parallel to antiparallel changes the direction of the excited spin waves. Our results raise the prospect of a chiral magnonic logic without the need for fragile surface states