Heroin type, injecting behavior, and HIV transmission. A simulation model of HIV incidence and prevalence.

Background and aimsUsing mathematical modeling to illustrate and predict how different heroin source-forms: "black tar" (BTH) and powder heroin (PH) can affect HIV transmission in the context of contrasting injecting practices. By quantifying HIV risk by these two heroin source-types we show how each affects the incidence and prevalence of HIV over time. From 1997 to 2010 PH reaching the United States was manufactured overwhelmingly by Colombian suppliers and distributed in the eastern states of the United States. Recently Mexican cartels that supply the western U.S. states have started to produce PH too, replacing Colombian distribution to the east. This raises the possibility that BTH in the western U.S. may be replaced by PH in the future.DesignWe used an agent-based model to evaluate the impact of use of different heroin formulations in high- and low-risk populations of persons who inject drugs (PWID) who use different types of syringes (high vs. low dead space) and injecting practices. We obtained model parameters from peer-reviewed publications and ethnographic research.ResultsHeating of BTH, additional syringe rinsing, and subcutaneous injection can substantially decrease the risk of HIV transmission. Simulation analysis shows that HIV transmission risk may be strongly affected by the type of heroin used. We reproduced historic differences in HIV prevalence and incidence. The protective effect of BTH is much stronger in high-risk compared with low-risk populations. Simulation of future outbreaks show that when PH replaces BTH we expect a long-term overall increase in HIV prevalence. In a population of PWID with mixed low- and high-risk clusters we find that local HIV outbreaks can occur even when the overall prevalence and incidence are low. The results are dependent on evidence-supported assumptions.ConclusionsThe results support harm-reduction measures focused on a reduction in syringe sharing and promoting protective measures of syringe rinsing and drug solution heating

Moment tensor inversions of icequakes on Gornergletscher, Switzerland

We have determined seismic source mechanisms for shallow and intermediate-depth icequake clusters recorded on the glacier Gornergletscher, Switzerland, during the summers of 2004 and 2006. The selected seismic events are part of a large data set of over 80,000 seismic events acquired with a dense seismic network deployed in order to study the yearly rapid drainage of Gornersee lake, a nearby ice-marginal lake. Using simple frequency and distance scaling and Green’s functions for a homogeneous half-space, we calculated moment tensor solutions for icequakes with M_w-1.5 using a full-waveform inversion method usually applied to moderate seismic events (M_w>4) recorded at local to regional distances (≈50–700 km). Inversions from typical shallow events are shown to represent tensile crack openings. This explains well the dominating Rayleigh waves and compressive first motions observed at all recording seismograms. As these characteristics can be observed in most icequake signals, we believe that the vast majority of icequakes recorded in the 2 yr is due to tensile faulting, most likely caused by surface crevasse openings. We also identified a shallow cluster with somewhat atypical waveforms in that they show less dominant Rayleigh waves and quadrantal radiation patterns of first motions. Their moment tensors are dominated by a large double-couple component, which is strong evidence for shear faulting. Although less than a dozen such icequakes have been identified, this is a substantial result as it shows that shear faulting in glacier ice is generally possible even in the absence of extreme flow changes such as during glacier surges. A third source of icequakes was located at 100 m depth. These sources can be represented by tensile crack openings. Because of the high-hydrostatic pressure within the ice at these depths, these events are most likely related to the presence of water lenses that reduce the effective stress to allow for tensile faulting

Atmospheric correction for MASTER image data using localized modelled and observed meteorology and trace gases

Atmospheric correction for remote sensing-based studies typically does not use information from spatio-temporally resolved meteorological models. We assessed the effect of using observations and mesoscale weather and chemical transport models on multispectral retrievals of land and ocean properties. We performed two atmospheric corrections on image data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS)/Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) airborne simulator over Monterey Bay, California. One correction used local atmospheric profiles of meteorology and trace gases at overpass and the other used the 1976 US Standard default atmospheric profile in the MODTRAN4 radiative transfer model.We found only minor impacts from atmospheric correction in the Fluorescence Line Height index of ocean chlorophyll, but substantive differences in retrievals of surface temperature and the Normalized Difference Vegetation Index. Improvements in sea surface temperature retrieval were validated by in situ measurements. Results indicate that spatio-temporally specific atmospheric correction factors from mesoscale models can improve retrievals of surface properties from remotely sensed image data

High-resolution global maps of tidal flat ecosystems from 1984 to 2019

Assessments of the status of tidal flats, one of the most extensive coastal ecosystems, have been hampered by a lack of data on their global distribution and change. Here we present globally consistent, spatially-explicit data of the occurrence of tidal flats, defined as sand, rock or mud flats that undergo regular tidal inundation. More than 1.3 million Landsat images were processed to 54 composite metrics for twelve 3-year periods, spanning four decades (1984–1986 to 2017–2019). The composite metrics were used as predictor variables in a machine-learning classification trained with more than 10,000 globally distributed training samples. We assessed accuracy of the classification with 1,348 stratified random samples across the mapped area, which indicated overall map accuracies of 82.2% (80.0–84.3%, 95% confidence interval) and 86.1% (84.2–86.8%, 95% CI) for version 1.1 and 1.2 of the data, respectively. We expect these maps will provide a means to measure and monitor a range of processes that are affecting coastal ecosystems, including the impacts of human population growth and sea level rise

Cold plasma sanitation system

Cold plasma is a relatively new nonthermal food processing method to perform antimicrobial treatment on the surface of foods. The main antimicrobial action is due to reactive chemical species and UV light generated by the cold plasma ionization process. There are a number of different plasma sanitation systems due to various possible electrode configurations (geometry, number, location) and operating conditions. A considerable amount of research and development has occurred in recent years on systems that operate at atmospheric pressures and relatively low temperatures. Our objective was to create a cold plasma sanitation system that could batch sanitize 25 to 50 lbs. of pecans for at least two minutes at a time. The system was be designed to be both hygienic (cleanable) and compatible with current equipment. It was designed to be resistant to oxidation as well. Additionally, the distance between the pecans and the electrodes had to be adjustable to investigate optimum pathogen reduction. Finally, the system utilized trays vertically stacked next to each other in order to create vertical columns. Gravity was used to dump the pecans into the top of these columns, and after they have been processed they are released from the bottom of the system. Testing was performed at the OSU Biosystems & Agricultural Engineering Lab and at the OSU Food and Agricultural Products Center

Engagement with care, substance use, and adherence to therapy in HIV/AIDS

Engagement with care for those living with HIV is aimed at establishing a strong relationship between patients and their health care provider and is often associated with greater adherence to therapy and treatment (Flickinger, Saha, Moore, and Beach, 2013). Substance use behaviors are linked with lower rates of engagement with care and medication adherence (Horvath, Carrico, Simoni, Boyer, Amico, and Petroli, 2013). This study is a secondary data analysis using a cross-sectional design from a larger randomized controlled trial (n = 775) that investigated the efficacy of a self-care symptom management manual for participants living with HIV. Participants were recruited from countries of Africa and the US. This study provides evidence that substance use is linked with lower self-reported engagement with care and adherence to therapy. Data on substance use and engagement are presented. Clinical implications of the study address the importance of utilizing health care system and policy factors to improve engagement with care

Earthquakes in Switzerland and surrounding regions during 2010

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2010. During this period, 407 earthquakes and 85 quarry blasts were detected and located in the region under consideration. With a total of only 19 events with ML≥2.5, the seismic activity in the year 2010 was below the average over the previous 35years. The two most noteworthy earthquakes were the ML3.4 Barrhorn event near Sankt Niklaus (VS) and the ML 3.0 event of Feldkirch, both of which produced shaking of intensity I

Earthquakes in Switzerland and surrounding regions during 2011

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2011. During this period, 522 earthquakes and 92 quarry blasts were detected and located in the region under consideration. With a total of only 10 events with M L≥2.5, the seismic activity in the year 2011 was far below the average over the previous 36years. Most noteworthy were the earthquake sequence of Sierre (VS) in January, with two events of M L 3.3 and 3.2, the M L 3.3 earthquake at a depth of 31km below Bregenz, and the M L 3.1 event near Delémont. The two strongest events near Sierre produced shaking of intensity I