2,176 research outputs found

    On Projective Representations of Finitely Generated Groups

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    For a finitely generated group G, we construct a representation group of G explicitly. Along the way, we describe the structure of the 2-cocycles of G. We also prove a characterization of monomial projective representations of finitely generated nilpotent groups and a characterization of polycyclic groups whose projective representations are finite dimensional.Comment: 22 page

    Eff ects of a parenting intervention to address maternal psychological wellbeing and child development and growth in rural Uganda: a community-based, cluster-randomised trial

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    Background Parenting interventions have been implemented to improve the compromised developmental potential among 39% of children younger than 5 years living in low-income and middle-income countries. Maternal wellbeing is important for child development, especially in children younger than 3 years who are vulnerable and dependent on their mothers for nutrition and stimulation. We assessed an integrated, community-based parenting intervention that targeted both child development and maternal wellbeing in rural Uganda. Methods In this community-based, cluster randomised trial, we assessed the eff ectiveness of a manualised, parenting intervention in Lira, Uganda. We selected and randomly assigned 12 parishes (1:1) to either parenting intervention or control (inclusion on a waitlist with a brief message on nutrition) groups using a computergenerated list of random numbers. Within each parish, we selected two to three eligible communities that had a parish offi ce or a primary school in which a preschool could be established, more than 75 households with children younger than 6 years, and at least 15 socially disadvantaged families (ie, maternal education of primary school level or lower) with at least one child younger than 36 months. Participants within communities were mother–child dyads, where the child was 12–36 months of age at enrolment, and the mother had low maternal education. In the parenting intervention group, participants attended 12 fortnightly peer-led group sessions focusing on child care and maternal wellbeing. The primary outcomes were cognitive and receptive language development, as measured with the Bayley Scales of Infant Development, 3rd edn. Secondary outcomes included self-reported maternal depressive symptoms, using the Center for Epidemiologic Studies Depression Scale, and child growth. Theoreticallyrelevant parenting practices, including the Home Observation for Measurement of the Environment inventory, and mother-care variables, such as perceived spousal support, were also assessed as potential mediators. Baseline assessments were done in January, 2013, and endline assessments were done in November, 2013, 3 months after completion of the programme. Ethics approval was received from Mbarara and McGill universities. This trial is registered with ClinicalTrials.gov, NCT01906606. Findings Between December, 2012, and January, 2013, 13 communities (194 dyads) were randomly assigned to receive intervention, and 12 communities (154 dyads) were assigned to a waitlist control. 319 dyads completed baseline measures (171 in the intervention group and 148 in the control group), and 291 dyads completed endline measures (160 in the intervention group and 131 in the control group). At endline, children in the intervention group had signifi cantly higher cognitive scores (58∙90 vs 55∙65, eff ect size 0∙36, 95% CI 0∙12–0∙59) and receptive language scores (23∙86 vs 22∙40, 0∙27, 0∙03–0∙50) than did children in the control group. Mothers in the intervention group reported signifi cantly fewer depressive symptoms (15∙36 vs 18∙61, –0∙391, –0∙62 to –0∙16) than did mothers in the control group. However, no diff erences were found in child growth between groups. Interpretation The 12 session integrated parenting intervention delivered by non-professional community members improved child development and maternal wellbeing in rural Uganda. Because this intervention was largely managed and implemented by a local organisation, using local community members and minimal resources, such a programme has the potential to be replicated and scaled up in other low-resource, village-based settings

    Effect of discrete time observations on synchronization in Chua model and applications to data assimilation

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    Recent studies show indication of the effectiveness of synchronization as a data assimilation tool for small or meso-scale forecast when less number of variables are observed frequently. Our main aim here is to understand the effects of changing observational frequency and observational noise on synchronization and prediction in a low dimensional chaotic system, namely the Chua circuit model. We perform {\it identical twin experiments} in order to study synchronization using discrete-in-time observations generated from independent model run and coupled unidirectionally to the model through xx, yy and zz separately. We observe synchrony in a finite range of coupling constant when coupling the x and y variables of the Chua model but not when coupling the z variable. This range of coupling constant decreases with increasing levels of noise in the observations. The Chua system does not show synchrony when the time gap between observations is greater than about one-seventh of the Lyapunov time. Finally, we also note that prediction errors are much larger when noisy observations are used than when using observations without noise.Comment: synchronization, Data assimilation, Chua model, 8 pages, 11 figure

    Reducing Chemical Exposures at Home: Opportunities For Action.

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    Indoor environments can influence human environmental chemical exposures and, ultimately, public health. Furniture, electronics, personal care and cleaning products, floor coverings and other consumer products contain chemicals that can end up in the indoor air and settled dust. Consumer product chemicals such as phthalates, phenols, flame retardants and per- and polyfluorinated alkyl substances are widely detected in the US general population, including vulnerable populations, and are associated with adverse health effects such as reproductive and endocrine toxicity. We discuss the implications of our recent meta-analysis describing the patterns of chemical exposures and the ubiquity of multiple chemicals in indoor environments. To reduce the likelihood of exposures to these toxic chemicals, we then discuss approaches for exposure mitigation: targeting individual behaviour change, household maintenance and purchasing decisions, consumer advocacy and corporate responsibility in consumer markets, and regulatory action via state/federal policies. There is a need to further develop evidence-based strategies for chemical exposure reduction in each of these areas, given the multi-factorial nature of the problem. Further identifying those at greatest risk; understanding the individual, household and community factors that influence indoor chemical exposures; and developing options for mitigation may substantially improve individuals’ exposures and health

    Predictability of soil moisture and river flows over France for the spring season

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    Sources of spring predictability of the hydrological system over France were studied on a seasonal time scale over the 1960–2005 period. Two random sampling experiments were set up in order to test the relative importance of the land surface initial state and the atmospheric forcing. The experiments were based on the SAFRAN-ISBA-MODCOU hydrometeorological suite which computed soil moisture and river flow forecasts over a 8-km grid and more than 880 river-gauging stations. Results showed that the predictability of hydrological variables primarily depended on the seasonal atmospheric forcing (mostly temperature and total precipitation) over most plains, whereas it mainly depended on snow cover over high mountains. However, the Seine catchment area was an exception as the skill mainly came from the initial state of its large and complex aquifers. Seasonal meteorological hindcasts with the Météo-France ARPEGE climate model were then used to force the ISBA-MODCOU hydrological model and obtain seasonal hydrological forecasts from 1960 to 2005 for the entire March-April-May period. Scores from this seasonal hydrological forecasting suite could thus be compared with the random atmospheric experiment. Soil moisture and river flow skill scores clearly showed the added value in seasonal meteorological forecasts in the north of France, contrary to the Mediterranean area where values worsened

    Electrochemical and thermal detection of allergenic substance lysozyme with molecularly imprinted nanoparticles

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    Lysozyme (LYZ) is a small cationic protein which is widely used for medical treatment and in the food industry to act as an anti-bacterial agent; however, it can trigger allergic reactions. In this study, high-affinity molecularly imprinted nanoparticles (nanoMIPs) were synthesized for LYZ using a solid-phase approach. The produced nanoMIPs were electrografted to screen-printed electrodes (SPEs), disposable electrodes with high commercial potential, to enable electrochemical and thermal sensing. Electrochemical impedance spectroscopy (EIS) facilitated fast measurement (5–10 min) and is able to determine trace levels of LYZ (pM) and can discriminate between LYZ and structurally similar proteins (bovine serum albumin, troponin-I). In tandem, thermal analysis was conducted with the heat transfer method (HTM), which is based on monitoring the heat transfer resistance at the solid–liquid interface of the functionalized SPE. HTM as detection technique guaranteed trace-level (fM) detection of LYZ but needed longer analysis time compared to EIS measurement (30 min vs 5–10 min). Considering the versatility of the nanoMIPs which can be adapted to virtually any target of interest, these low-cost point-of-care sensors hold great potential to improve food safety

    Liver Enzyme Abnormalities and Associated Risk Factors in HIV Patients on Efavirenz-Based HAART with or without Tuberculosis Co-Infection in Tanzania.

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    To investigate the timing, incidence, clinical presentation, pharmacokinetics and pharmacogenetic predictors for antiretroviral and anti-tuberculosis drug induced liver injury (DILI) in HIV patients with or without TB co-infection. A total of 473 treatment naïve HIV patients (253 HIV only and 220 with HIV-TB co-infection) were enrolled prospectively. Plasma efavirenz concentration and CYP2B6*6, CYP3A5*3, *6 and *7, ABCB1 3435C/T and SLCO1B1 genotypes were determined. Demographic, clinical and laboratory data were collected at baseline and up to 48 weeks of antiretroviral therapy. DILI case definition was according to Council for International Organizations of Medical Sciences (CIOMS). Incidence of DILI and identification of predictors was evaluated using Cox Proportional Hazards Model. The overall incidence of DILI was 7.8% (8.3 per 1000 person-week), being non-significantly higher among patients receiving concomitant anti-TB and HAART (10.0%, 10.7 per 1000 person-week) than those receiving HAART alone (5.9%, 6.3 per 1000 person-week). Frequency of CYP2B6*6 allele (p = 0.03) and CYP2B6*6/*6 genotype (p = 0.06) was significantly higher in patients with DILI than those without. Multivariate cox regression model indicated that CYP2B6*6/*6 genotype and anti-HCV IgG antibody positive as significant predictors of DILI. Median time to DILI was 2 weeks after HAART initiation and no DILI onset was observed after 12 weeks. No severe DILI was seen and the gain in CD4 was similar in patients with or without DILI. Antiretroviral and anti-tuberculosis DILI does occur in our setting, presenting early following HAART initiation. DILI seen is mild, transient and may not require treatment interruption. There is good tolerance to HAART and anti-TB with similar immunological outcomes. Genetic make-up mainly CYP2B6 genotype influences the development of efavirenz based HAART liver injury in Tanzanians

    Chemoenzymatic surface decoration of Nisin-shelled nanoemulsions: novel targeted drug-nanocarriers for cancer applications

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    Nisin, a peptide used as a natural food preservative, is employed in this work for the development of a novel nanocarrier system. Stable and uniform nisin-shelled nanoemulsions (NSNE) with a diameter of 100 ± 20 nm were successfully prepared using 20 kHz flow-through ultrasonication technique. The NSNE showed limited toxicity, high bactericidal activity and high drug loading capacity (EE 65 % w/w). In addition, the nisin shell was exploited for the site-specific attachment of a recombinantly produced cancer targeting ligand (αHER2LPETG IgG). Employing a unique two phases (bio-click) approach which involved both Sortase A mediated Azide Bioconjugation (SMAB) and Strain Promoted Azide Alkyne Cycloaddition (SPAAC) reactions, targeted NSNE (NSNEDOX-αHER2 IgG) were successfully assembled and loaded with the chemotherapeutic drug Doxorubicin (DOX). Finally, NSNEDOX-αHER2 IgG showed cancer-specific binding and augmented cytotoxicity to HER2 expressing tumour cells

    Di-μ-chlorido-bis­{[2-({[2-(2-pyrid­yl)eth­yl](2-pyridylmeth­yl)amino}meth­yl)phenol]zinc(II)} bis­(perchlorate) dihydrate

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    The title compound, [Zn2Cl2(C20H21N3O)2](ClO4)2·2H2O, consists of a dinuclear ZnII cationic complex, two disordered perchlorate anions and two water mol­ecules as solvate. The [Zn2(μ-Cl)2(HL)2]2+ cation [HL is 2-({[2-(2-pyrid­yl)eth­yl](2-pyridylmeth­yl)amino}meth­yl)phenol] has a centrosymmetric structure with the ZnII ions in a distorted octa­hedral environment surrounded by an N3OCl2 donor set. HL acts as a tetra­dentate ligand through three N atoms from one amine group and two pyridyl arms and one O atom from the phenolic arm. The three N-donor sites of the HL ligand are arranged in meridional fashion, with the pyridine rings coordinated in trans positions with respect to each other. Consequently, the amine and phenol groups are trans to the asymmetric di-μ-chlorido exogenous bridges. A polymeric chain is formed along [010] by C(12)R 4 2(8) inter­molecular hydrogen bonding. The perchlorate anion is disordered and was modelled by two sites in a 0.345 (18):0.655 (18) ratio. Water–perchlorate O—H⋯O inter­actions form cyclic structures, while phenol–water O—H⋯O inter­actions generate an infinite chain. In addition, weak inter­molecular C—H⋯π(Ph) inter­actions between pyridine donor and phenol acceptor groups of neighboring cations build a two-dimensional polymeric structure parallel to (110)
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