Heavy Carriers and Non-Drude Optical Conductivity in MnSi

Optical properties of the weakly helimagnetic metal MnSi have been determined in the photon energy range from 2 meV to 4.5 eV using the combination of grazing incidence reflectance at 80 degrees (2 meV to 0.8 eV) and ellipsometry (0.8 to 4.5 eV). As the sample is cooled below 100 K the effective mass becomes strongly frequency dependent at low frequencies, while the scattering rate developes a linear frequency dependence. The complex optical conductivity can be described by the phenomenological relation \sigma(\omega,T) \propto (\Gamma(T)+i\omega)^{-1/2} used for cuprates and ruthenates.Comment: 5 pages, ReVTeX 4, 5 figures in eps forma

Towards causal benchmarking of bias in face analysis algorithms

Measuring algorithmic bias is crucial both to assess algorithmic fairness, and to guide the improvement of algorithms. Current methods to measure algorithmic bias in computer vision, which are based on observational datasets, are inadequate for this task because they conflate algorithmic bias with dataset bias. To address this problem we develop an experimental method for measuring algorithmic bias of face analysis algorithms, which manipulates directly the attributes of interest, e.g., gender and skin tone, in order to reveal causal links between attribute variation and performance change. Our proposed method is based on generating synthetic ``transects'' of matched sample images that are designed to differ along specific attributes while leaving other attributes constant. A crucial aspect of our approach is relying on the perception of human observers, both to guide manipulations, and to measure algorithmic bias. Besides allowing the measurement of algorithmic bias, synthetic transects have other advantages with respect to observational datasets: they sample attributes more evenly allowing for more straightforward bias analysis on minority and intersectional groups, they enable prediction of bias in new scenarios, they greatly reduce ethical and legal challenges, and they are economical and fast to obtain, helping make bias testing affordable and widely available. We validate our method by comparing it to a study that employs the traditional observational method for analyzing bias in gender classification algorithms. The two methods reach different conclusions. While the observational method reports gender and skin color biases, the experimental method reveals biases due to gender, hair length, age, and facial hair

Responsible Innovation in Business

This chapter introduces responsible innovation in a business context. The first part explains the basic terms that constitute responsible innovation from a busi-ness perspective. The second part presents tangible business practices that opera-tionalise responsible innovation and introduces two good practice examples that hint at the variety of ways in which responsible innovation can be implemented in companies

A real-time, quantitative PCR method using hydrolysis probes for the monitoring of Plasmodium falciparum load in experimentally infected human volunteers

Background: The accurate quantification of Plasmodium falciparum parasite numbers by PCR is an important tool for monitoring growth kinetics in subjects infected and subsequently treated with anti-malarial agents

General Practice and Pandemic Influenza: A Framework for Planning and Comparison of Plans in Five Countries

BACKGROUND: Although primary health care, and in particular, general practice will be at the frontline in the response to pandemic influenza, there are no frameworks to guide systematic planning for this task or to appraise available plans for their relevance to general practice. We aimed to develop a framework that will facilitate planning for general practice, and used it to appraise pandemic plans from Australia, England, USA, New Zealand and Canada. METHODOLOGY/PRINCIPAL FINDINGS: We adapted the Haddon matrix to develop the framework, populating its cells through a multi-method study that incorporated the peer-reviewed and grey literature, interviews with general practitioners, practice nurses and senior decision-makers, and desktop simulation exercises. We used the framework to analyse 89 publicly-available jurisdictional plans at similar managerial levels in the five countries. The framework identifies four functional domains: clinical care for influenza and other needs, public health responsibilities, the internal environment and the macro-environment of general practice. No plan addressed all four domains. Most plans either ignored or were sketchy about non-influenza clinical needs, and about the contribution of general practice to public health beyond surveillance. Collaborations between general practices were addressed in few plans, and inter-relationships with the broader health system, even less frequently. CONCLUSIONS: This is the first study to provide a framework to guide general practice planning for pandemic influenza. The framework helped identify critical shortcomings in available plans. Engaging general practice effectively in planning is challenging, particularly where governance structures for primary health care are weak. We identify implications for practice and for research

A Mathematical model for Astrocytes mediated LTP at Single Hippocampal Synapses

Many contemporary studies have shown that astrocytes play a significant role in modulating both short and long form of synaptic plasticity. There are very few experimental models which elucidate the role of astrocyte over Long-term Potentiation (LTP). Recently, Perea & Araque (2007) demonstrated a role of astrocytes in induction of LTP at single hippocampal synapses. They suggested a purely pre-synaptic basis for induction of this N-methyl-D- Aspartate (NMDA) Receptor-independent LTP. Also, the mechanisms underlying this pre-synaptic induction were not investigated. Here, in this article, we propose a mathematical model for astrocyte modulated LTP which successfully emulates the experimental findings of Perea & Araque (2007). Our study suggests the role of retrograde messengers, possibly Nitric Oxide (NO), for this pre-synaptically modulated LTP.Comment: 51 pages, 15 figures, Journal of Computational Neuroscience (to appear

A distal region of the human TGM1 promoter is required for expression in transgenic mice and cultured keratinocytes

BACKGROUND: TGM1(transglutaminase 1) is an enzyme that crosslinks the cornified envelope of mature keratinocytes. Appropriate expression of the TGM1 gene is crucial for proper keratinocyte function as inactivating mutations lead to the debilitating skin disease, lamellar ichthyosis. TGM1 is also expressed in squamous metaplasia, a consequence in some epithelia of vitamin A deficiency or toxic insult that can lead to neoplasia. An understanding of the regulation of this gene in normal and abnormal differentiation states may contribute to better disease diagnosis and treatment. METHODS: In vivo requirements for expression of the TGM1 gene were studied by fusing various lengths of promoter DNA to a reporter and injecting the DNA into mouse embryos to generate transgenic animals. Expression of the reporter was ascertained by Western blotting and immunohistochemistry. Further delineation of a transcriptionally important distal region was determined by transfections of progressively shortened or mutated promoter DNA into cultured keratinocytes. RESULTS: In vivo analysis of a reporter transgene driven by the TGM1 promoter revealed that 1.6 kilobases, but not 1.1 kilobases, of DNA was sufficient to confer tissue-specific and cell layer-specific expression. This same region was responsible for reporter expression in tissues undergoing squamous metaplasia as a response to vitamin A deprivation. Mutation of a distal promoter AP1 site or proximal promoter CRE site, both identified as important transcriptional elements in transfection assays, did not prevent appropriate expression. Further searching for transcriptional elements using electrophoretic mobility shift (EMSA) and transfection assays in cultured keratinocytes identified two Sp1 elements in a transcriptionally active region between -1.6 and -1.4 kilobases. While mutation of either Sp1 site or the AP1 site singly had only a small effect, mutation of all three sites eliminated nearly all the transcriptional activity. CONCLUSIONS: A distal region of the TGM1 gene promoter, containing AP1 and Sp1 binding sites, is evolutionarily conserved and responsible for high level expression in transgenic mice and in transfected keratinocyte cultures

Stochastic Gravity: Theory and Applications

Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel.In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime: we compute the two-point correlation functions for the linearized Einstein tensor and for the metric perturbations. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit

Bacteraemia among severely malnourished children infected and uninfected with the human immunodeficiency virus-1 in Kampala, Uganda

BACKGROUND: To establish the magnitude of bacteraemia in severely malnourished children, and describe the types of bacteria and antimicrobial sensitivity by HIV status. METHOD: Isolates were recovered from 76 blood specimens. Antibiotic susceptibility tests were performed using commercial antibiotic disks and demographic and clinical findings were recorded. RESULTS: Of the 450 children 63% were male; median age 17.0 months (inter quartile range, IQR 12–24) and 57% had oedema. 151 (36.7 %) of 411 tested HIV-positive; 76 (17.1%) of 445 blood specimens grew bacterial isolates; 58% were Gram negative – S. typhimurium (27.6%) and S. enteriditis (11.8%). Staph. aureus (26.3%) and Strep. pneumoniae (13.2%) were the main Gram positive organisms. There was no difference in the risk of bacteraemia by HIV status, age < 24 months, male sex, or oedema, except for oral thrush (OR 2.3 CI 1.0–5.1) and hypoalbuminaemia (OR 3.5 CI 1.0–12.1). Isolates from severely immuno-suppressed children (CD4% <15%) were more likely to grow Salmonella enteriditis (OR 5.4; CI 1.6 – 17.4). The isolates were susceptible (≥ 80%) to ciprofloxacin, ceftriaxone and gentamicin; with low susceptibility to chlorampenicol, ampicillin (< 50%) and co-trimoxazole (<25%). Suspicion of bacteraemia had 95.9% sensitivity and 99.2% specificity. Among bacteraemic children, mortality was higher (43.5% vs 20.5%) in the HIV-positive; OR 3.0 (95%CI 1.0, 8.6). CONCLUSION: Bacteraemia affects 1 in every 6 severely malnourished children and carries high mortality especially among the HIV-positive. Given the high level of resistance to common antibiotics, there is need for clinical trials to determine the best combinations of antibiotics for management of bacteraemia in severely malnourished children