Fast Computation of Smith Forms of Sparse Matrices Over Local Rings

We present algorithms to compute the Smith Normal Form of matrices over two families of local rings. The algorithms use the \emph{black-box} model which is suitable for sparse and structured matrices. The algorithms depend on a number of tools, such as matrix rank computation over finite fields, for which the best-known time- and memory-efficient algorithms are probabilistic. For an \nxn matrix $A$ over the ring \Fzfe, where $f^e$ is a power of an irreducible polynomial f \in \Fz of degree $d$, our algorithm requires \bigO(\eta de^2n) operations in \F, where our black-box is assumed to require \bigO(\eta) operations in \F to compute a matrix-vector product by a vector over \Fzfe (and $\eta$ is assumed greater than \Pden). The algorithm only requires additional storage for \bigO(\Pden) elements of \F. In particular, if \eta=\softO(\Pden), then our algorithm requires only \softO(n^2d^2e^3) operations in \F, which is an improvement on known dense methods for small $d$ and $e$. For the ring \ZZ/p^e\ZZ, where $p$ is a prime, we give an algorithm which is time- and memory-efficient when the number of nontrivial invariant factors is small. We describe a method for dimension reduction while preserving the invariant factors. The time complexity is essentially linear in $\mu n r e \log p,$ where $\mu$ is the number of operations in \ZZ/p\ZZ to evaluate the black-box (assumed greater than $n$) and $r$ is the total number of non-zero invariant factors. To avoid the practical cost of conditioning, we give a Monte Carlo certificate, which at low cost, provides either a high probability of success or a proof of failure. The quest for a time- and memory-efficient solution without restrictions on the number of nontrivial invariant factors remains open. We offer a conjecture which may contribute toward that end.Comment: Preliminary version to appear at ISSAC 201

A general approach for hysteresis-free, operationally stable metal halide perovskite field-effect transistors.

Despite sustained research, application of lead halide perovskites in field-effect transistors (FETs) has substantial concerns in terms of operational instabilities and hysteresis effects which are linked to its ionic nature. Here, we investigate the mechanism behind these instabilities and demonstrate an effective route to suppress them to realize high-performance perovskite FETs with low hysteresis, high threshold voltage stability (ΔVt 1 cm2/V·s at room temperature. We show that multiple cation incorporation using strain-relieving cations like Cs and cations such as Rb, which act as passivation/crystallization modifying agents, is an effective strategy for reducing vacancy concentration and ion migration in perovskite FETs. Furthermore, we demonstrate that treatment of perovskite films with positive azeotrope solvents that act as Lewis bases (acids) enables a further reduction in defect density and substantial improvement in performance and stability of n-type (p-type) perovskite devices

Watershed Classification Predicts Streamflow Regime and Organic Carbon Dynamics in the Northeast Pacific Coastal Temperate Rainforest

Watershed classification has long been a key tool in the hydrological sciences, but few studies have been extended to biogeochemistry. We developed a combined hydro-biogeochemical classification for watersheds draining to the coastal margin of the Northeast Pacific coastal temperate rainforest (1,443,062 km2), including 2,695 small coastal rivers (SCR) and 10 large continental watersheds. We used cluster analysis to group SCR watersheds into 12 types, based on watershed properties. The most important variables for distinguishing SCR watershed types were evapotranspiration, slope, snowfall, and total precipitation. We used both streamflow and dissolved organic carbon (DOC) measurements from rivers (n = 104 and 90 watersheds respectively) to validate the classification. Watershed types corresponded with broad differences in streamflow regime, mean annual runoff, DOC seasonality, and mean DOC concentration. These links between watershed type and river conditions enabled the first region-wide empirical characterization of river hydrobiogeochemistry at the land-sea margin, spanning extensive ungauged and unsampled areas. We found very high annual runoff (mean > 3,000 mm, n = 10) in three watershed types totaling 59,024 km2 and ranging from heavily glacierized mountain watersheds with high flow in summer to a rain-fed mountain watershed type with high flow in fall-winter. DOC hotspots (mean > 4 mg L−1, n = 14) were found in three other watershed types (48,557 km2) with perhumid rainforest climates and less-mountainous topography. We described four patterns of DOC seasonality linked to watershed hydrology, with fall-flushing being widespread. Hydro-biogeochemical watershed classification may be useful for other complex regions with sparse observation networks.Author Contributions: Conceptualization: Ian J. W. Giesbrecht, Suzanne E. Tank, Gordon W. Frazer, Eran Hood, David E. Butman, David V. D’Amore, Allison Bidlack, Ken P. Lertzman Data curation: Ian J. W. Giesbrecht, Santiago G. Gonzalez Arriola, David Hutchinson Formal analysis: Ian J. W. Giesbrecht, Gordon W. Frazer, Santiago G. Gonzalez ArriolaYe

Low particulate carbon to nitrogen ratios in marine surface waters of the Arctic

During the Canada Three Oceans and Joint Ocean Ice Study projects in the summers of 2007 and 2008, we measured particulate organic carbon to nitrogen ratios (POC:PON) throughout the euphotic zone in subarctic and arctic waters. Depth-integrated values averaged 2.65 (±0.19) in the Beaufort Sea and Canada Basin (BS-CB domain), and were much lower than both the Redfield ratio (6.6) and the average ratios (3.9 to 5.6) measured across other arctic-subarctic domains. Average uptake ratios of C and N (ρC:ρN) were also lower (0.87±0.14) in BS-CB than in the other four domains (2.10 to 3.51). Decreasing POC:PON ratios were associated with low concentrations of phytoplankton C, reduced abundance of biogenic silica (bSiO2), a smaller relative contribution of the >5 µm fraction to total chlorophyll a and a larger relative contribution of small flagellates (<8 µm) to phytoplankton C. In the subsurface chlorophyll a maximum (SCM) within the BS-CB domain, phytoplankton C represented only ~13% of POC, and therefore low POC:PON may be influenced by the presence of heterotrophic microbes. These ratios are supported by data obtained during other arctic programs in 2006, 2008 and 2009. Previous work has suggested a link between freshening of surface waters and increasing dominance of picophytoplankton and bacterioplankton in the Canada Basin, and the low POC:PON ratios measured during this study may be a consequence of this shift. Our results have ramifications for the conversion between C- and N-based estimates of primary productivity, and for biogeochemical modeling of marine arctic waters.Facultad de Ciencias Naturales y Muse

Psychological side effects of immune therapies: symptoms and pathomechanism

Immunotherapies revolutionised the treatment of several disorders but show specific side-effect profiles which frequently involve psychological symptoms. Long term interferon-alpha (IFN-alpha) therapy can cause wide-ranging psychiatric side-effects from fatigue, insomnia, anxiety to full-blown depression. This treatment-emergent depression shares several symptoms with major depressive disorder (MDD) with a predominance of somatic/neurovegetative symptoms, and can be treated with antidepressants. However, this experience directed research to inflammatory mechanisms in MDD. MDD has been confirmed as a heterogeneous disorder with a subgroup of patients suffering from low-grade chronic inflammation and frequently resistant to traditional antidepressant treatment. Thus future research should develop strategies to identify those MDD patients who could benefit from drugs acting through inflammatory pathways

Wheelchair service provision education for healthcare professional students, healthcare personnel and educators across low- to high-resourced settings: a scoping review

Purpose This review aimed to collate and summarize available research literature about wheelchair service provision education available to healthcare professional students, healthcare personnel and educators across low- to high-resourced settings. Methods The Joanna Briggs Institute methodological steps for scoping reviews were followed. Included studies were mainly sourced from Medline, Embase, CINAHL, Scopus, Academic Search Complete and ProQuest. Independent title, abstract and full-text screening with defined inclusion and exclusion criteria was performed. All screening and extraction were performed independently by two authors. A thematic approach was used to synthesize results. Data extracted from included studies were charted according to a template that we created. The study quality was also appraised. Results A total of 25 articles were included (11, 36% from high-income settings) with 12 (48%) observational studies and 13 (52%) experimental studies. The literature addressed three main topics: (1) assessing wheelchair service provision knowledge, (2) implementing training interventions using in-person, online and/or hybrid learning approaches and (3) describing current wheelchair service provision education globally. The most frequently reported training programs used were the Wheelchair Skills Program and the World Health Organization Wheelchair Service Training Package – Basic Level. Conclusion Limited information has been published about the integration of wheelchair content into the curricula of professional rehabilitation programs. Efforts to build international partnerships, improve the quality and currency of training programs and build resources that can assist educators in the integration of wheelchair-related content into professional rehabilitation programs should be prioritized. Implications for Rehabilitation This is the first review that examined and synthesized the current state of wheelchair service provision education for rehabilitation students and personnel across low- to high-income countries. Findings from this review indicate that there is limited information about the integration of wheelchair-related content into professional rehabilitation programs. Efforts to build international partnerships, standardize wheelchair service provision content and evaluation and integrate training into professional rehabilitation programs worldwide should be prioritized

An Intervention to Reduce HIV Risk Behavior of Substance-Using Men Who Have Sex with Men: A Two-Group Randomized Trial with a Nonrandomized Third Group

In a randomized trial of a behavioral intervention among substance-using men who have sex with men, aimed at reducing sexual risk behavior, Mansergh and colleagues fail to find evidence of a reduction in risk from the intervention

Drug education in victorian schools (DEVS): the study protocol for a harm reduction focused school drug education trial

<p>Abstract</p> <p>Background</p> <p>This study seeks to extend earlier Australian school drug education research by developing and measuring the effectiveness of a comprehensive, evidence-based, harm reduction focused school drug education program for junior secondary students aged 13 to 15 years. The intervention draws on the recent literature as to the common elements in effective school curriculum. It seeks to incorporate the social influence of parents through home activities. It also emphasises the use of appropriate pedagogy in the delivery of classroom lessons.</p> <p>Methods/Design</p> <p>A cluster randomised school drug education trial will be conducted with 1746 junior high school students in 21 Victorian secondary schools over a period of three years. Both the schools and students have actively consented to participate in the study. The education program comprises ten lessons in year eight (13-14 year olds) and eight in year nine (14-15 year olds) that address issues around the use of alcohol, tobacco, cannabis and other illicit drugs. Control students will receive the drug education normally provided in their schools. Students will be tested at baseline, at the end of each intervention year and also at the end of year ten. A self completion questionnaire will be used to collect information on knowledge, patterns and context of use, attitudes and harms experienced in relation to alcohol, tobacco, cannabis and other illicit drug use. Multi-level modelling will be the method of analysis because it can best accommodate hierarchically structured data. All analyses will be conducted on an Intent-to-Treat basis. In addition, focus groups will be conducted with teachers and students in five of the 14 intervention schools, subsequent to delivery of the year eight and nine programs. This will provide qualitative data about the effectiveness of the lessons and the relevance of the materials.</p> <p>Discussion</p> <p>The benefits of this drug education study derive both from the knowledge gained by trialling an optimum combination of innovative, harm reduction approaches with a large, student sample, and the resultant product. The research will provide better understanding of what benefits can be achieved by harm reduction education. It will also produce an intervention, dealing with both licit and illicit drug use that has been thoroughly evaluated in terms of its efficacy, and informed by teacher and student feedback. This makes available to schools a comprehensive drug education package with prevention characteristics and useability that are well understood.</p> <p>Trial registration</p> <p>Australia and New Zealand Clinical Trials Register (ANZCTR): <a href="http://www.anzctr.org.au/ACTRN12612000079842.aspx">ACTRN12612000079842</a></p

Dissociated control as a signature of typological variability in high hypnotic suggestibility

This study tested the prediction that dissociative tendencies modulate the impact of a hypnotic induction on cognitive control in different subtypes of highly suggestible individuals. Low suggestible (LS), low dissociative highly suggestible (LDHS), and high dissociative highly suggestible (HDHS) participants completed the Stroop colornaming task in control and hypnosis conditions. The magnitude of conflict adaptation (faster response times on incongruent trials preceded by an incongruent than those preceded by a congruent trial) was used as a measure of cognitive control. LS and LDHS participants displayed marginally superior up-regulation of cognitive control following a hypnotic induction, whereas HDHS participants’ performance declined. These findings indicate that dissociative tendencies modulate the influence of a hypnotic induction on cognitive control in high hypnotic suggestibility and suggest that HS individuals are comprised of distinct subtypes with dissimilar cognitive profiles