Carbon Concentration Dependence of the Superconducting Transition Temperature and Structure of MgCxNi3

The crystal structure of the superconductor MgCxNi3 is reported as a function of carbon concentration determined by powder neutron diffraction. The single-phase perovskite structure was found in only a narrow range of carbon content, 0.88 < x < 1.0. The superconducting transition temperature was found to decrease systematically with decreasing carbon concentration. The introduction of carbon vacancies has a significant effect on the positions of the Ni atoms. No evidence for long range magnetic ordering was seen by neutron diffraction for carbon stoichiometries within the perovskite phase stability range.Comment: 4 figure

Health-care sector and complementary medicine: practitioners’ experiences of delivering acupuncture in the public and private sectors

AIM: The aim was to identify similarities and differences between private practice and the National Health Service (NHS) in practitioners' experiences of delivering acupuncture to treat pain. We wished to identify differences that could affect patients' experiences and inform our understanding of how trials conducted in private clinics relate to NHS clinical practice. BACKGROUND: Acupuncture is commonly used in primary care for lower back pain and is recommended in the National Institute for Health and Clinical Excellence's guidelines. Previous studies have identified differences in patients' accounts of receiving acupuncture in the NHS and in the private sector. The major recent UK trial of acupuncture for back pain was conducted in the private sector. METHODS: Semi-structured qualitative interviews were conducted with 16 acupuncturists who had experience of working in the private sector (n = 7), in the NHS (n =3), and in both the sectors (n = 6). The interviews lasted between 24 and 77 min (median=49 min) and explored acupuncturists' experiences of treating patients in pain. Inductive thematic analysis was used to identify similarities and differences across private practice and the NHS.FINDINGS: The perceived effectiveness of acupuncture was described consistently and participants felt they did (or would) deliver acupuncture similarly in NHS and in private practice. In both the sectors, patients sought acupuncture as a last resort and acupuncturist-patient relationships were deemed important. Acupuncture availability differed across sectors: in the NHS it was constrained by Trust policies and in the private sector by patients' financial resources. There were greater opportunities for autonomous practice in the private sector and regulation was important for different reasons in each sector. In general, NHS practitioners had Western-focussed training and also used conventional medical techniques, whereas private practitioners were more likely to have Traditional Chinese training and to practise other complementary therapies in addition to acupuncture. Future studies should examine the impact of these differences on patients' clinical outcomes

Examining issues influencing green building technologies adoption : the United States green building experts' perspectives

Green building (GB) has been viewed as an effective means to implement environmental, economic, and social sustainability in the construction industry. For the adoption of GB technologies (GBTs) to continue to succeed and gain popularity, a better understanding of the key issues influencing its progress is crucial. While numerous studies have examined the issues influencing green innovations adoption in general, few have specifically done so in the context of GBTs. This study aims to investigate the underpinnings of GBTs adoption in the following areas: (1) the critical barriers inhibiting the adoption of GBTs, (2) major drivers for adopting GBTs, and (3) important strategies to promote GBTs adoption. To achieve these objectives, a questionnaire survey was carried out with 33 GB experts from the United States. Ranking analysis was used to identify the significant issues associated with GBTs adoption. Resistance to change, a lack of knowledge and awareness, and higher cost have been the most critical barriers. The major drivers for adopting GBTs are greater energy- and water-efficiency, and company image and reputation. The analysis results also indicate that the most important strategies to promote the adoption of GBTs are financial and further market-based incentives, availability of better information on cost and benefits of GBTs, and green labelling and information dissemination. The findings provide a valuable reference for industry practitioners and researchers to deepen their understanding of the major issues that influence GB decision-making, and for policy makers aiming at promoting the adoption of GBTs in the construction industry to develop suitable policies and incentives. This study contributes to expanding the body of knowledge about the influences that hinder and those that foster GBTs implementation

Effect of Boron substitution on the superconductivity of non-oxide perovskite MgCNi3

We report synthesis, structural and magnetic (DC and AC) properties of Boron substituted MgCNi3 superconductor. A series of polycrystalline bulk samples Mg1.2C1.6-xBxNi3 (x = 0.0, 0.08 and 0.16) is synthesized through standard solid-state reaction route, which are found to crystallize in cubic perovskite structure with space group Pm3m. Rietveld analysis of observed XRD data show that lattice parameters expand from a = 3.8106 (4) {\AA} for pure, to 3.8164 (2) {\AA} and 3.8173 (5) {\AA} for 5% and 10% Boron substituted samples respectively. DC magnetization exhibited superconducting transition (Tc) at around 7.3 K for pure sample, and the same decreases slightly with Boron substitution. The lower critical field (Hc1) at 2 K is around 150 Oe for pure sample, which increases slightly with Boron substitution. For pure sample the upper critical field (Hc2) being determined from AC susceptibility measurements is 11.6 kOe and 91.70 kOe with 50% and 90% diamagnetism criteria respectively, which decreases to 5.57 kOe and 42.5 kOe respectively for 10% Boron substituted sample. 10% Boron substitution at Carbon site has decreased both the Hc2 and Tc. On the other hand lower critical field (Hc1) at 2 K is slightly increased from around 150 Oe for pure sample, to 200 Oe for 10% Boron substituted sample. Seemingly, the Carbon site Boron substitution induced disorder though has increased slightly the Hc1 but with simultaneous decrease in superconducting transition temperature (Tc) and upper critical field (Hc2). The high relative proportion of Ni in studied MgCNi3 suggests that magnetic interactions are important and non-oxide perovskite structure make it interesting.Comment: 13 Pages Text + Figures: comments/suggestions ([email protected]

Variable Selection with False Discovery Control

Technological advances that allow routine identification of high-dimensional risk factors have led to high demand for statistical techniques that enable full utilization of these rich sources of information for genome-wide association studies (GWAS). Variable selection for censored outcome data as well as control of false discoveries (i.e. inclusion of irrelevant variables) in the presence of high-dimensional predictors present serious challenges. In the context of survival analysis with high-dimensional covariates, this paper develops a computationally feasible method for building general risk prediction models, while controlling false discoveries. We have proposed a high-dimensional variable selection method by incorporating stability selection to control false discovery. Comparisons between the proposed method and the commonly used univariate and Lasso approaches for variable selection reveal that the proposed method yields fewer false discoveries. The proposed method is applied to study the associations of 2,339 common single-nucleotide polymorphisms (SNPs) with overall survival among cutaneous melanoma (CM) patients. The results have confirmed that BRCA2 pathway SNPs are likely to be associated with overall survival, as reported by previous literature. Moreover, we have identified several new Fanconi anemia (FA) pathway SNPs that are likely to modulate survival of CM patients

Unrecognised Outbreak: Human parainfluenza virus infections in a pediatric oncology unit. A new diagnostic PCR and virus monitoring system may allow early detection of future outbreaks.

Background: Human parainfluenza viruses (HPIVs) are significant causes of both upper and lower respiratory tract infections with type 3 (HPIV3) causing the most severe disease in the immunocompromised cohorts.  The objective of this study was to analyse the epidemiological nature of a cluster of cases of HPIV3 in a pediatric oncology unit of a major teaching hospital. Methods: In order to determine whether the activity observed represented a deviation from the norm, seasonal trends of HPIV3 in the surrounding geographical area as well as on the ward in question were analysed.  The genetic link between cases was established by the phylogenetic analysis of the non-coding hypervariable region between the M (Matrix) and F (fusion) genes of HPIV3. The 15 cases involved and 15 unrelated cases were sequenced.  Transmission routes were subsequently inferred and visualized using Konstanz Information Miner (KNIME) 3.3.2. Results: Of the 15 cases identified, 14 were attributed to a point source outbreak. Two out of 14 outbreak cases were found to differ by a single mutation A182C. The outbreak strain was also seen in 1 out of 15 unrelated cases, indicating that it was introduced from the community. Transmission modeling was not able to link all the cases and establish a conclusive chain of transmission. No staff were tested during the outbreak period. No deaths occurred as a result of the outbreak. Conclusion: A point source outbreak of HPIV3 was recognized post factum on an oncology pediatric unit in a major teaching hospital. This raised concern about the possibility of a future more serious outbreak. Weaknesses in existing systems were identified and a new dedicated respiratory virus monitoring system introduced.  Pediatric oncology units require sophisticated systems for early identification of potentially life-threatening viral outbreaks

Influence of Carbon Concentration on the Superconductivity in MgCxNi3

The influence of carbon concentration on the superconductivity (SC) in MgC$_{x}$Ni$_3$ has been investigated by measuring the low temperature specific heat combined with first principles electronic structure calculation. It is found that the specific heat coefficient $\gamma_n=C_{en}/T$ of the superconducting sample ($x\approx1$) in normal state is twice that of the non-superconducting one ($x\approx 0.85$). The comparison of measured $\gamma_n$ and the calculated electronic density of states (DOS) shows that the effective mass renormalization changes remarkably as the carbon concentration changes. The large mass renormalization for the superconducting sample and the low $T_{c}$(7K) indicate that more than one kind of boson mediated electron-electron interactions exist in MgC$_{x}$Ni$_3$.Comment: 4 pages, 4 figure

Detecting the direction of a signal on high-dimensional spheres: Non-null and Le Cam optimality results

We consider one of the most important problems in directional statistics, namely the problem of testing the null hypothesis that the spike direction $\theta$ of a Fisher-von Mises-Langevin distribution on the $p$-dimensional unit hypersphere is equal to a given direction $\theta_0$. After a reduction through invariance arguments, we derive local asymptotic normality (LAN) results in a general high-dimensional framework where the dimension $p_n$ goes to infinity at an arbitrary rate with the sample size $n$, and where the concentration $\kappa_n$ behaves in a completely free way with $n$, which offers a spectrum of problems ranging from arbitrarily easy to arbitrarily challenging ones. We identify various asymptotic regimes, depending on the convergence/divergence properties of $(\kappa_n)$, that yield different contiguity rates and different limiting experiments. In each regime, we derive Le Cam optimal tests under specified $\kappa_n$ and we compute, from the Le Cam third lemma, asymptotic powers of the classical Watson test under contiguous alternatives. We further establish LAN results with respect to both spike direction and concentration, which allows us to discuss optimality also under unspecified $\kappa_n$. To investigate the non-null behavior of the Watson test outside the parametric framework above, we derive its local asymptotic powers through martingale CLTs in the broader, semiparametric, model of rotationally symmetric distributions. A Monte Carlo study shows that the finite-sample behaviors of the various tests remarkably agree with our asymptotic results.Comment: 47 pages, 4 figure

Field demonstration of a cost-optimized solar powered electrodialysis reversal desalination system in rural India

This study provides experimental validation of a previously published optimal design theory for photovoltaic (PV)-powered electrodialysis reversal (EDR) desalination systems. The prior work describes the co-optimization of PV and EDR subsystems, and flexible operation to accommodate daily and annual solar irradiance variability, significantly reducing water cost. This study presents the fabrication of a PV-EDR pilot system designed using the co-optimization theory and field testing results from the rural village of Chelluru, India. Testing in the field enabled observation and evaluation of real-world factors on system performance, resulting in updates to the previous theory to include unaccounted factors that affect costs, including: filling and draining of water tanks, salt and water accumulation in tanks from prior batches, unexpected energy losses due to locally purchased converters, and scaling in the ED stack. Therefore, water cost in the PV-EDR pilot system was updated from previous estimates based on field performance. The estimated capital cost and lifetime cost of the Chelluru system are 34% and 45% lower, respectively, than the corresponding costs if the PV-EDR system was designed using conventional design practice. The theory and experimental insights presented in this paper will enable desalination engineers to better design and optimize PV-EDR systems

Voltage- and flow-controlled electrodialysis batch operation : flexible and optimized brackish water desalination

Electrodialysis (ED) desalination has been demonstrated to be more energy-efficient, provide higher-recovery, and be lower-cost for producing drinking water from saline groundwater compared to reverse osmosis. These benefits of ED could translate into cost-effective, renewable-powered desalination solutions. However, the challenge of using a variable power source (e.g. solar) with traditional steady-state ED operation requires batteries to reshape the power source to match the desalination load; these batteries often contribute to a large fraction of the produced water cost. In this study, we propose a time-variant voltage- and flow-controlled ED operation that can enable highly flexible desalination from variable power sources, including renewables, with negligible batteries, potentially leading to reduced water costs compared to what existing technology can provide. A model-based controller is presented which varies applied ED stack voltage and pumping flow rate to match power consumption to a variable source while maximizing desalination rate throughout an ED batch. The utility of the controller was demonstrated with a pilot-scale system tested with brackish groundwater, which operated as expected under varying fixed power levels and a real solar irradiance profile. The pilot system achieved a production rate up to 45% higher than that of an equivalently sized traditional steady-state ED system