Transient Random Walks in Random Environment on a Galton-Watson Tree

We consider a transient random walk $(X_n)$ in random environment on a Galton--Watson tree. Under fairly general assumptions, we give a sharp and explicit criterion for the asymptotic speed to be positive. As a consequence, situations with zero speed are revealed to occur. In such cases, we prove that $X_n$ is of order of magnitude $n^{\Lambda}$, with $\Lambda \in (0,1)$. We also show that the linearly edge reinforced random walk on a regular tree always has a positive asymptotic speed, which improves a recent result of Collevecchio \cite{Col06}

Plasmodium transmission blocking activities of Vernonia amygdalina extracts and isolated compounds

BACKGROUND: Medicinal plants are a validated source for discovery of new leads and standardized herbal medicines. The aim of this study was to assess the activity of Vernonia amygdalina leaf extracts and isolated compounds against gametocytes and sporogonic stages of Plasmodium berghei and to validate the findings on field isolates of Plasmodium falciparum. METHODS: Aqueous (Ver-H2O) and ethanolic (Ver-EtOH) leaf extracts were tested in vivo for activity against sexual and asexual blood stage P. berghei parasites. In vivo transmission blocking effects of Ver-EtOH and Ver-H2O were estimated by assessing P. berghei oocyst prevalence and density in Anopheles stephensi mosquitoes. Activity targeting early sporogonic stages (ESS), namely gametes, zygotes and ookinetes was assessed in vitro using P. berghei CTRPp.GFP strain. Bioassay guided fractionation was performed to characterize V. amygdalina fractions and molecules for anti-ESS activity. Fractions active against ESS of the murine parasite were tested for ex vivo transmission blocking activity on P. falciparum field isolates. Cytotoxic effects of extracts and isolated compounds vernolide and vernodalol were evaluated on the human cell lines HCT116 and EA.hy926. RESULTS: Ver-H2O reduced the P. berghei macrogametocyte density in mice by about 50% and Ver-EtOH reduced P. berghei oocyst prevalence and density by 27 and 90%, respectively, in An. stephensi mosquitoes. Ver-EtOH inhibited almost completely (>90%) ESS development in vitro at 50 μg/mL. At this concentration, four fractions obtained from the ethylacetate phase of the methanol extract displayed inhibitory activity >90% against ESS. Three tested fractions were also found active against field isolates of the human parasite P. falciparum, reducing oocyst prevalence in Anopheles coluzzii mosquitoes to one-half and oocyst density to one-fourth of controls. The molecules and fractions displayed considerable cytotoxicity on the two tested cell-lines. CONCLUSIONS: Vernonia amygdalina leaves contain molecules affecting multiple stages of Plasmodium, evidencing its potential for drug discovery. Chemical modification of the identified hit molecules, in particular vernodalol, could generate a library of druggable sesquiterpene lactones. The development of a multistage phytomedicine designed as preventive treatment to complement existing malaria control tools appears a challenging but feasible goal

Sector-specific development and policy vulnerability in the Philippines

Ministry of Education, Singapore under its Academic Research Funding Tier

Interventions for female drug-using offenders

Key results: We identified nine trials of female drug-using offenders. Three studies included evaluations of therapeutic communities in comparison to: i) an alternative sentencing option; ii) a substance misuse educational cognitive skills programme; and iii) gender-responsive substance abuse treatment for women in prison in comparison to standard therapeutic communities. Two studies evaluated community-based management; one compared to standard probation and the other compared to standard parole supervision. Two studies evaluated a cognitive behavioural programme versus treatment as usual and combined cognitive behavioural treatment and acceptance and commitment therapy versus waiting list control. One study of a pharmacological intervention in comparison to a placebo or treatment as usual. One study compared interpersonal psychotherapy to an attention matched control psychoeducational control. Overall, the findings suggest that any psychosocial treatment in comparison to treatment as usual had an impact on reducing subsequent reincarceration, but not rearrest or drug misuse. We found individual treatment interventions had differing effects. We identified too few studies to evaluate whether the treatment setting (for example, court or community) had an impact on the success of such programmes. Promising results highlight the use of psychosocial treatments in the reduction of reincarceration. No information is provided on the cost and cost-effectiveness of these studies. In conclusion, high quality research is required to evaluate the effectiveness of different treatment options for female drug-using offenders. Further information on the processes involved in the engagement of women mandated to substance abuse programmes, together with evaluations of cost-effectiveness research, will enable policy makers to make informed choices about commissioning the use of adapted programmes specifically targeted at female offenders

Pharmacological interventions for drug-using offenders.

BACKGROUND: The review represents one in a family of four reviews focusing on a range of different interventions for drug-using offenders. This specific review considers pharmacological interventions aimed at reducing drug use or criminal activity, or both, for illicit drug-using offenders. OBJECTIVES: To assess the effectiveness of pharmacological interventions for drug-using offenders in reducing criminal activity or drug use, or both. SEARCH METHODS: We searched Fourteen electronic bibliographic databases up to May 2014 and five additional Web resources (between 2004 and November 2011). We contacted experts in the field for further information. SELECTION CRITERIA: We included randomised controlled trials assessing the efficacy of any pharmacological intervention a component of which is designed to reduce, eliminate or prevent relapse of drug use or criminal activity, or both, in drug-using offenders. We also report data on the cost and cost-effectiveness of interventions. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures as expected by Cochrane. MAIN RESULTS: Fourteen trials with 2647 participants met the inclusion criteria. The interventions included in this review report on agonistic pharmacological interventions (buprenorphine, methadone and naltrexone) compared to no intervention, other non-pharmacological treatments (e.g. counselling) and other pharmacological drugs. The methodological trial quality was poorly described, and most studies were rated as 'unclear' by the reviewers. The biggest threats to risk of bias were generated through blinding (performance and detection bias) and incomplete outcome data (attrition bias). Studies could not be combined all together because the comparisons were too different. Only subgroup analysis for type of pharmacological treatment were done. When compared to non-pharmacological, we found low quality evidence that agonist treatments are not effective in reducing drug use or criminal activity, objective results (biological) (two studies, 237 participants (RR 0.72 (95% CI 0.51 to 1.00); subjective (self-report), (three studies, 317 participants (RR 0.61 95% CI 0.31 to 1.18); self-report drug use (three studies, 510 participants (SMD: -0.62 (95% CI -0.85 to -0.39). We found low quality of evidence that antagonist treatment was not effective in reducing drug use (one study, 63 participants (RR 0.69, 95% CI 0.28 to 1.70) but we found moderate quality of evidence that they significantly reduced criminal activity (two studies, 114 participants, (RR 0.40, 95% CI 0.21 to 0.74).Findings on the effects of individual pharmacological interventions on drug use and criminal activity showed mixed results. In the comparison of methadone to buprenorphine, diamorphine and naltrexone, no significant differences were displayed for either treatment for self report dichotomous drug use (two studies, 370 participants (RR 1.04, 95% CI 0.69 to 1.55), continuous measures of drug use (one study, 81 participants, (mean difference (MD) 0.70, 95% CI -5.33 to 6.73); or criminal activity (one study, 116 participants, (RR 1.25, 95% CI 0.83 to 1.88) between methadone and buprenorphine. Similar results were found for comparisons with diamorphine with no significant differences between the drugs for self report dichotomous drug use for arrest (one study, 825 participants, (RR 1.25, 95% CI 1.03 to 1.51) or naltrexone for dichotomous measures of reincarceration (one study, 44 participants, (RR 1.10, 95% CI 0.37 to 3.26), and continuous outcome measure of crime, (MD -0.50, 95% CI -8.04 to 7.04) or self report drug use (MD 4.60, 95% CI -3.54 to 12.74). AUTHORS' CONCLUSIONS: When compared to non-pharmacological treatment, agonist treatments did not seem effective in reducing drug use or criminal activity. Antagonist treatments were not effective in reducing drug use but significantly reduced criminal activity. When comparing the drugs to one another we found no significant differences between the drug comparisons (methadone versus buprenorphine, diamorphine and naltrexone) on any of the outcome measures. Caution should be taken when interpreting these findings, as the conclusions are based on a small number of trials, and generalisation of these study findings should be limited mainly to male adult offenders. Additionally, many studies were rated at high risk of bias