Single-crystal X-ray structure analysis of the superionic conductor Li10GeP2S12

Tetragonal Li10GeP2S12 (LGPS) is the best solid Li ion conductor known to date. So far, the structure of the electrolyte was only determined from powder diffraction and Rietveld refinement. Here, we present the first single-crystal structure analysis of the tetragonal LGPS structure. The reported structure is largely verified. However, an additional Li position is clearly identified which might have a significant impact on the Li ion dynamics. All Li positions are partially occupied - a prerequisite for Li superionic conductors - and form a network of interconnected Li diffusion pathways. Therefore, we suggest that Li diffusion in this record solid electrolyte is less anisotropic than previously claimed

The Security of Self-Differencing Avalanche Photodiodes for Quantum Key Distribution

Quantum key distribution (QKD) allows two users to communicate with information theoretic security by encoding information on single photons. This security is based on the laws of physics and as such can never be broken in theory. However, in practice, components do not always behave according to their theoretical models and these deviations can be exploited by an eavesdropper. In recent years, exposing loopholes in QKD systems, known as quantum hacking, has attracted significant attention. The components most susceptible to being hacked are the single-photon detectors, often avalanche photodiodes (APDs), as they are directly exposed to the optical channel. Whilst measurement-device-independent QKD removes detector vulnerability from the system, secure key rates with this technique can be much lower than point-to-point links. As such, mitigating attacks on QKD systems is a pressing challenge in QKD. In this thesis, the focus is on a special class of detectors, self-differencing APDs (SD-APDs), which have facilitated state-of-the art demonstrations of QKD. The susceptibility of SD-APDs to blinding attacks, the most explored and successful attack to date, was investigated and it was shown that by following best practice for their operation, such an attack would be unsuccessful. We have also proposed and developed a countermeasure such that the onus for appropriate operation could be removed from the user. We have also explored an arguably more dangerous attack, in the form of the after-gate attack. We have shown that delayed detection events, ordinarily considered detrimental in QKD, can provide inherent protection against this attack. Finally, backflashes in GHz-gated APDs were investigated for the first time and it was shown that threat they pose to QKD security is negligible. These results highlight the inherent protection to a number of attacks that self-differencing APDs possess. We stress that the findings presented in this thesis are also applicable to other types of fast-gated InGaAs APDs that don't possess self-differencing circuitry.EPSRC ICASE Award with Toshib

Medical students’ personal experiences, religion, and spirituality explain their (dis)comfort with a patient’s religious needs

Background: Physicians often avoid discussing patients’ religious and spiritual concerns, even though most patients (i.e., 50-94%) want integrated care.  To address this gap, medical students interviewed a Standardized Patient (SP) who was upset because the daughter did not confront her fiancée about converting to Orthodox Judaism.  Students reflected on how their own religion and spirituality affected engaging with their patient. Methods: With a 97% response rate, 231 first-year medical students responded to open-ended questions about their patient encounter.  For this quantitative content analysis, we used inductive reasoning, identifying three themes:  (1) impact of students’ own religion on their comfort, (2) change in comfort, and (3) their learning. We used deductive reasoning to compare qualitative results from half of the students who began the curriculum with a questionnaire about their own spirituality with the other students completing afterwards. Results: Most students said being religious positively influenced their comfort, whether they were also Orthodox Jewish or from a different religion. Among uncomfortable students (6.5%), some attributed this to not being religious. Some students (4.8%) grew more comfortable discussing the religious issue, and 18.2% became uncomfortable due to lacking knowledge of Orthodox Judaism and the awkwardness of the topic.  Students who had completed the questionnaire beforehand gave more comments about connecting with their patients than students who completed the questionnaire afterwards (X2=11.047, p<.001). Conclusions: Students’ own religion influenced their comfort with discussing religious concerns, with some feeling more connected and others becoming uncomfortable. This finding helps inform medical educators about teaching mind-body-spirit care

Exercise and the Timing of Snack Choice: Healthy Snack Choice is Reduced in the Post-Exercise State

Acute exercise can induce either a compensatory increase in food intake or a reduction in food intake, which results from appetite suppression in the post-exercise state. The timing of food choice—choosing for immediate or later consumption—has been found to influence the healthfulness of foods consumed. To examine both of these effects, we tested in our study whether the timing of food choice interacts with exposure to exercise to impact food choices such that choices would differ when made prior to or following an exercise bout. Visitors to a university recreational center were equipped with an accelerometer prior to their habitual workout regime, masking the true study purpose. As a reward, participants were presented with a snack for consumption after workout completion. Participants made their snack choice from either an apple or chocolate brownie after being pseudo-randomly assigned to choose prior to (“before”) or following workout completion (“after”). Complete data were available for 256 participants (54.7% male, 22.1 ± 3.1 years, 24.7 ± 3.7 kg/m2) who exercised 65.3 ± 22.5 min/session. When compared with “before,” the choice of an apple decreased (73.7% vs. 54.6%) and the choices of brownie (13.9% vs. 20.2%) or no snack (12.4% vs. 25.2%) increased in the “after” condition (X2 = 26.578, p \u3c 0.001). Our results provide support for both compensatory eating and exercise-induced anorexia. More importantly, our findings suggest that the choice of food for post-exercise consumption can be altered through a simple behavioral intervention

Aspirin Dosing for the Prevention and Treatment of Ischemic Stroke: An Indication-Specific Review of the Literature

OBJECTIVE: To evaluate the efficacy of aspirin for the treatment and prevention of ischemic stroke and identify the minimum dose proven to be effective for each indication. DATA SOURCES: PubMed and MEDLINE searches (January 2009–January 2010) were performed to identify primary literature, using search terms including aspirin, stroke prevention, acute ischemic stroke, acetylsalicylic acid, atrial fibrillation, myocardial infarction, and carotid endarterectomy. Additionally, reference citations from publications identified were reviewed. STUDY SELECTION AND DATA EXTRACTION: Articles published in English were evaluated and relevant primary literature evaluating the efficacy of aspirin in the prevention of stroke was included in this review. DATA SYNTHESIS: Antiplatelet therapy is the benchmark for the prevention of ischemic stroke. Aspirin has been proven to prevent ischemic stroke in a variety of settings. Despite the frequency at which aspirin continues to be prescribed in patients at risk of ischemic stroke, there remains confusion in clinical practice as to what minimum dose is required in various at-risk patients. A thorough review of the primary literature suggests that low-dose (50–81 mg daily) aspirin is insufficient for some indications. Acute ischemic stroke treatment requires 160–325 mg, while atrial fibrillation and carotid arterial disease require daily doses of 325 and 81–325 mg, respectively. CONCLUSIONS: Available evidence suggests that aspirin dosing must be individualized according to indication. Recommendations provided by national guidelines at times recommend lower doses of aspirin than have been proven effective. Higher doses are indicated for stroke prevention in atrial fibrillation (325mg) and acute ischemic stroke patients (160–325 mg). Aspirin has not yet been proven effective for primary prevention of strokes in men, and a minimum dose for these patients cannot be determined from the available data

Rewriting History: Repurposing Domain-Specific CGRAs

Coarse-grained reconfigurable arrays (CGRAs) are domain-specific devices promising both the flexibility of FPGAs and the performance of ASICs. However, with restricted domains comes a danger: designing chips that cannot accelerate enough current and future software to justify the hardware cost. We introduce FlexC, the first flexible CGRA compiler, which allows CGRAs to be adapted to operations they do not natively support. FlexC uses dataflow rewriting, replacing unsupported regions of code with equivalent operations that are supported by the CGRA. We use equality saturation, a technique enabling efficient exploration of a large space of rewrite rules, to effectively search through the program-space for supported programs. We applied FlexC to over 2,000 loop kernels, compiling to four different research CGRAs and 300 generated CGRAs and demonstrate a 2.2$\times$ increase in the number of loop kernels accelerated leading to 3$\times$ speedup compared to an Arm A5 CPU on kernels that would otherwise be unsupported by the accelerator

Exercise and the Timing of Snack Choice: Healthy Snack Choice is Reduced in the Post-Exercise State

Acute exercise can induce either a compensatory increase in food intake or a reduction in food intake, which results from appetite suppression in the post-exercise state. The timing of food choice—choosing for immediate or later consumption—has been found to influence the healthfulness of foods consumed. To examine both of these effects, we tested in our study whether the timing of food choice interacts with exposure to exercise to impact food choices such that choices would differ when made prior to or following an exercise bout. Visitors to a university recreational center were equipped with an accelerometer prior to their habitual workout regime, masking the true study purpose. As a reward, participants were presented with a snack for consumption after workout completion. Participants made their snack choice from either an apple or chocolate brownie after being pseudo-randomly assigned to choose prior to (“before”) or following workout completion (“after”). Complete data were available for 256 participants (54.7% male, 22.1 ± 3.1 years, 24.7 ± 3.7 kg/m2) who exercised 65.3 ± 22.5 min/session. When compared with “before,” the choice of an apple decreased (73.7% vs. 54.6%) and the choices of brownie (13.9% vs. 20.2%) or no snack (12.4% vs. 25.2%) increased in the “after” condition (X2 = 26.578, p \u3c 0.001). Our results provide support for both compensatory eating and exercise-induced anorexia. More importantly, our findings suggest that the choice of food for post-exercise consumption can be altered through a simple behavioral intervention

Best-Practice Criteria for Practical Security of Self-Differencing Avalanche Photodiode Detectors in Quantum Key Distribution

Fast-gated avalanche photodiodes (APDs) are the most commonly used single photon detectors for high-bit-rate quantum key distribution (QKD). Their robustness against external attacks is crucial to the overall security of a QKD system, or even an entire QKD network. We investigate the behavior of a gigahertz-gated, self-differencing (In,Ga)As APD under strong illumination, a tactic Eve often uses to bring detectors under her control. Our experiment and modeling reveal that the negative feedback by the photocurrent safeguards the detector from being blinded through reducing its avalanche probability and/or strengthening the capacitive response. Based on this finding, we propose a set of best-practice criteria for designing and operating fast-gated APD detectors to ensure their practical security in QKD

Optimismus trotz steigender Gewalt: Afghanistan nach dem ISAF-Abzug

Am 22. Juni 2015 griffen Taliban das afghanische Parlament in Kabul an und attackierten damit erneut eine staatliche Einrichtung im Zentrum der politischen Macht. Sechs Monate nach dem Ende des 13-jährigen NATO-Kampfeinsatzes nehmen im Westen Befürchtungen vor einer weiteren Eskalation der Gewalt und einer Machtzunahme der Taliban zu. Seit dem Ende des ISAF-Truppenabzugs kommt es vermehrt zu direkten Kämpfen zwischen afghanischen nationalen Sicherheitskräften und den Taliban. Die objektive Sicherheitssituation für die Bevölkerung hat sich verschlechtert. Dennoch bewerten viele Menschen im Norden des Landes die Folgen des Truppenabzugs Ende 2014/Anfang 2015 optimistischer als noch im Jahr 2012. Die Anzahl der Gewaltopfer ist seit dem Jahr 2012 landesweit deutlich angestiegen und hat mit 3.699 zivilen Toten und 6.849 Verletzten im Jahr 2014 einen neuen Höchststand erreicht. Die Zunahme direkter gewaltsamer Auseinandersetzungen zwischen staatlichen Sicherheitskräften, lokalen Milizen und den Taliban erhöhen die Gefahr eines neuen Bürgerkriegs in Afghanistan. Ungeachtet dieser Entwicklung zeigen Meinungsumfragen aus dem Norden des Landes aus dem Jahr 2012 und von Ende 2014 bzw. Anfang 2015, dass die Befragten mögliche Sicherheitsrisiken des ISAF-Truppenabzugs inzwischen deutlich geringer einschätzen als noch im Jahr 2012. Die Wahlen und die Regierungsbildung im Jahr 2014, die stärkere Präsenz der afghanischen Sicherheitskräfte und die anhaltende internationale Unterstützung des Landes könnten für die positiveren Einschätzungen der Jahre 2014/2015 verantwortlich sein. Die jüngste Taliban-Offensive seit April 2015 verdeutlicht aber auch die Volatilität der Sicherheitslage. Es besteht das Risiko, dass diese Entwicklungen die vorsichtig optimistische Stimmung in der Bevölkerung wieder zunichte machen