How patterns of injecting drug use evolve in a cohort of people who inject drugs

This research found an overall movement away from street based drug purchasing and drug use, towards more activity in private settings, which has important implications for the harms experienced by people who inject drugs. Foreword This paper investigates the frequency of intravenous drug use in a cohort of people who inject drugs, and the decline in use over time. It provides an important indication of the effectiveness of current interventions at reducing the consumption of illicit drugs. Comparisons are made between the injection frequency of participants on or off Opioids Substitution Therapy (OST), and according to the settings in which drugs are most frequently purchased and used (eg street, house). This research found an overall movement away from street based drug purchasing and drug use, towards more activity in private settings. This has important implications for the harms experienced by people who inject drugs. Intravenous drug use was persistent, with only slow declines observed in the frequency of the cohort’s overall use. Lower injection frequency was associated with use in private rather than public locations as well as the uptake of OST. Additional work is needed to understand how this change in setting is affected by and also affects current interventions, and whether it can be used to help further reduce injecting drug use

Who suggests drinking less? Demographic and national differences in informal social controls on drinking

Objective: The purpose of this study was to examine variation in reports of pressuring others to drink less, as a form of informal social control of drinking, across countries and different types of relationship to the respondent. Method: A cross-sectional survey was administered to 19,945 respondents ages 18-69 years in 14 countries included in the data set of the Gender, Alcohol and Culture: An International Study (GENACIS). Outcome variables were respondents' reports of pressuring others to drink less (yes/no) across a variety of relationships (their partners, other family members, workmates, or friends). Multilevel, multivariable logistic regression analysis was carried out on each outcome variable. The fixed-effects components included the Level 1 (individual) covariates of respondent age, gender, drinking status, and education level as well as the Level 2 (country level) covariates of percentage female drinkers and purchasing power parity. The random-effects components included country and current drinking status. Results: Respondents most frequently reported pressuring male friends to drink less (18%), followed by male family members (other than partners, 15%), partners (15%), work colleagues (12%), female friends (9%), female family members (other than partners, 6%), and children (5%). There was marked variation across countries, with pressuring frequently reported in Uganda, Costa Rica, and Nicaragua across most relationship types. Multivariable logistic regression revealed consistent effects of gender, with women more likely than men to report pressuring others to drink less across most relationship types. The patterns in relation to education status and age were less consistent and varied across relationship type. Conclusions: Informal social control of drinking varies dramatically according to whom is most likely to pressure whom to drink less as well as the country in which people live

Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic

The Beta Triangle, a region of the oligotrophic subtropical eastern North Atlantic Ocean, is notorious for its enigmatic oxygen, carbon, and nitrogen balances, in which nutrient supply is said to explain only a fraction of production necessary for estimated carbon export. Rates of dissolved organic carbon accumulation and dissolved organic nitrogen utilization in surface water and an assessment of oxygen utilized, organic matter consumed, and nitrate and phosphate regenerated in subsurface water, show that conventional production estimates miss substantial shares of biotic production. The shallow export of total organic carbon, predominantly dissolved (DOC), by subduction is responsible for about 50–70% of apparent oxygen utilization in subsurface water between the base of the surface layer at ca. 140 m and ca. 195 m depth, but it is insignificant below. Additionally, there is an estimated accumulation of 1.0 to 1.75 mol DOC m−2 a−1 in surface water. Including DOC dynamics in its carbon balance reveals the surface of this ultra-oligotrophic part of the ocean to be net autotrophic. Increasing subsurface values of excess nitrogen (DINxs) imply the export of nitrogen from surface water stemming from production not exclusively fuelled by new nitrate supplied from below. Total organic nitrogen (almost exclusively dissolved, DON) is consumed in the surface layer at a rate estimated at 0.13 to 0.23 mol m−2 a−1. There is no variation in dissolved organic phosphorus (DOP) in the same direction. DON utilization thus contributes to the pronounced subsurface DINxs signature. DOC export and accumulation are important in the carbon balance in surface and near-surface water. DON utilization and, probably, N2 fixation contribute significant amounts to the nitrogen supply of surface water. These processes can close part of the enigmatic carbon and nitrogen balances in the Beta Triangle. There are, however, no comparable processes which can explain the equally enigmatic situation concerning phosphorus supply in this area

Initiation to heroin injecting among heroin users in Sydney, Australia: cross sectional survey

BACKGROUND: Heroin injection is associated with health and social problems including hepatitis C virus (HCV) transmission. Few studies have examined the circumstances surrounding initiation to heroin injecting, especially current users initiating others. The current study aimed to examine the age of first heroin use and injection; administration route of first heroin use; relationship to initiator; the initiation of others among a group of heroin users; and to examine these factors in relation to HCV status and risk. METHOD: Heroin users in Sydney were recruited through needle and syringe programs, a methadone clinic and snowballing. Participants were interviewed about their own initiation to heroin use, blood-borne virus risk and knowledge, and whether they had initiated others to heroin injecting. Information on HCV status was collected via self-report. Data was analysed using univariate and multivariate statistical techniques for Normally distributed continuous and categorical data. RESULTS: The study recruited 399 heroin users, with a mean age of 31 years, 63% were male, 77% reported heroin as their primary drug and 59% were HCV positive (self-report). Mean age at first heroin use and injection was 19 and 21 years, respectively. The majority of heroin users commenced heroin use via injecting (65%), younger users (<25 years, 25–30 years) were less likely than older users (>30 years) to commence heroin use parenterally. Participants were initiated to injection mainly by friends (63%). Thirty-seven percent reported initiating others to heroin injection, but few factors were related to this behaviour. Those with longer heroin using careers were more likely to report initiating others to heroin injection, but were no more likely to have done so in the preceding 12 months. Participants who had initiated others were more likely to have shared injecting equipment (12 vs 23%), but were no more likely to be HCV positive (self-report) than those who did not. CONCLUSION: Interventions to prevent heroin users initiating others to injecting are necessary. Peer groups may be well positioned to implement such interventions

A new perspective on environmental controls of marine nitrogen fixation

Growing slowly, marine N2 fixers are generally expected to be competitive only where nitrogen (N) supply is low relative to that of phosphorus (P) with respect to the cellular N:P ratio (R) of non-fixing phytoplankton. This is at odds with observed high N2 fixation rates in the oligotrophic North Atlantic where the ratio of nutrients supplied to the surface is elevated in N relative to the average R (16:1). In this study, we investigate several mechanisms to solve this puzzle: iron limitation, phosphorus enhancement by preferential remineralization or stoichiometric diversity of phytoplankton, and dissolved organic phosphorus (DOP) utilization. Combining resource competition theory and a global coupled ecosystem-circulation model we find that the additional N and energy investments required for exo-enzymatic break-down of DOP gives N2 fixers a competitive advantage in oligotrophic P-starved regions. Accounting for this mechanism expands the ecological niche of N2-fixers also to regions where the nutrient supply is high in N relative to R, yielding, in our model, a pattern consistent with the observed high N2-fixation rates in the oligotrophic North Atlantic