A comparative study of parameterized and full thermal-convection models in the interpretation of heat flow from cratons and mobile belts

Heat flow from Archean cratons worldwide is typically lower than from younger mobile belts surrounding them. The contrast in heat flow between cratons and mobile belts has been attributed in previous studies to the greater thermal resistance of thicker lithosphere beneath the cratons which impedes the flow of mantle heat through the cratons and forces more mantle heat to escape through thinner mobile belt lithosphere. This interpretation is based on thermal models which employ a parameterized convection algorithm to calculate heat transfer in the sublithospheric mantle. We test this interpretation by comparing thermal models constructed using the parameterized convection scheme with models developed using an algorithm for full thermal convection. We show that thermal models constructed using the two different convection algorithms yield similar surface heat flow and thermal structure to moderate depths within the lithosphere. Therefore, we conclude that the interpretation of the heat-flow observations in terms of thicker lithosphere under Archean cratons than under mobile belts is robust in the sense that surface heat flow is not sensitive to the details of heat transfer within the convecting mantle and how deep mantle heat is delivered to the base of the lithosphere.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74756/1/j.1365-246X.1993.tb04665.x.pd

Perceived, anticipated and experienced stigma: exploring manifestations and implications for young people's sexual and reproductive health and access to care in North-Western Tanzania

This work was conducted under the HPP, a five-year cooperative agreement supported by United States Agency for International Development [grant number AID-OAA-A-10-00067]

Disentangling HIV and AIDS Stigma in Ethiopia,Tanzania and Zambia

The International Center for Research on Women (ICRW), in partnership with organizations in Ethiopia, Tanzania, and Zambia, led a study of HIV and AIDS-related stigma and discrimination in these three countries. This project, conducted from April 2001 to September 2003, unraveled the complexities around stigma by investigating the causes, manifestations and consequences of HIV and AIDS-related stigma and discrimination in sub-Saharan Africa. It then uses this analysis to suggest program interventions. Structured text analysis of 730 qualitative transcripts (650 interviews and 80 focus group discussions) and quantitative analysis of 400 survey respondents from rural and urban areas in these countries revealed the following main insights about the causes, context, experience and consequences of stigma: The main causes of stigma relate to incomplete knowledge, fears of death and disease, sexual norms and a lack of recognition of stigma. Insufficient and inaccurate knowledge combines with fears of death and disease to perpetuate beliefs in casual transmission and, thereby, avoidance of those with HIV. The knowledge that HIV can be transmitted sexually combines with an association of HIV with socially “improper” sex, such that people with HIV are stigmatized for their perceived immoral behavior. Finally, people often do not recognize that their words or actions are stigmatizing. Socio-economic status, age and gender all influence the experience of stigma. The poor are blamed less for their infection than the rich, yet they face greater stigma because they have fewer resources to hide an HIV-positive status. Youth are blamed in all three countries for spreading HIV through what is perceived as their highly risky sexual behavior. While both men and women are stigmatized for breaking sexual norms, gender-based power results in women being blamed more easily. At the same time, the consequences of HIV infection, disclosure, stigma and the burden of care are higher for women than for men. People living with HIV and AIDS face physical and social isolation from family, friends, and community; gossip, name-calling and voyeurism; and a loss of rights, decision-making power and access to resources and livelihoods. People with HIV internalize these experiences and consequently feel guilty, ashamed and inferior. They may, as a result, isolate themselves and lose hope. Those associated with people with HIV and AIDS, especially family members, friends and caregivers, face many of these same experiences in the form of secondary stigma. People living with HIV and AIDS and their families develop various strategies to cope with stigma. Decisions around disclosure depend on whether or not disclosing would help to cope (through care) or make the situation worse (through added stigma). Some cope by participating in networks of people with HIV and actively working in the field of HIV or by confronting stigma in their communities. Others look for alternative explanations for HIV besides sexual transmission and seek comfort, often turning to religion to do so. Stigma impedes various programmatic efforts. Testing, disclosure, prevention and care and support for people with HIV are advocated, but are impeded by stigma. Testing and disclosure are recognized as difficult because of stigma, and prevention is hampered because preventive methods such as condom use or discussing safe sex are considered indications of HIV infection or immoral behaviors and are thus stigmatized. Available care and support are accompanied by judgmental attitudes and isolating behavior, which can result in people with HIV delaying care until absolutely necessary. There are also many positive aspects of the way people deal with HIV and stigma. People express good intentions to not stigmatize those with HIV. Many recognize that their limited knowledge has a role in perpetuating stigma and are keen to learn more. Families, religious organizations and communities provide care, empathy and support for people with HIV and AIDS. Finally, people with HIV themselves overcome the stigma they face to challenge stigmatizing social norms. Our study points to five critical elements that programs aiming to tackle stigma need to address: Create greater recognition of stigma and discrimination. Foster in-depth, applied knowledge about all aspects of HIV and AIDS through a participatory and interactive process. Provide safe spaces to discuss the values and beliefs about sex, morality and death that underlie stigma. Find common language to talk about stigma. Ensure a central, contextually-appropriate and ethically-responsible role for people with HIV and AIDS While all individuals and groups have a role in reducing stigma, policymakers and programmers can start with certain key groups that our study suggests are a priority: Families caring for people living with HIV and AIDS: programs can help families both to cope with the burden of care and also to recognize and modify their own stigmatizing behavior. NGOs and other community-based organizations: NGOs can train their own staff to recognize and deal with stigma, incorporate ways to reduce stigma in all activities, and critically examine their communication methods and materials. Religious and faith-based organizations: these can be supportive of people living with HIV and AIDS in their role as religious leaders and can incorporate ways to reduce stigma in their community service activitie

Mantle Transition Zone Structure beneath Kenya and Tanzania: More Evidence for a Deep-Seated Thermal Upwelling in the Mantle

Here we investigate the thermal structure of the mantle beneath the eastern Branch of the East African Rift system in Kenya and Tanzania. We focus on the structure of the mantle transition zone, as delineated by stacking of receiver functions. The top of the transition zone (the 410 km discontinuity) displays distinctive topography, and is systematically depressed beneath the rift in Kenya and northern Tanzania and adjacent volcanic fields. This depression is indicative of a localized ∼350 °C thermal anomaly. In contrast, the bottom of the transition zone (the 660 km discontinuity) is everywhere depressed. This region-wide depression is best explained as a Ps conversion from the majorite—perovskite transition of anomalously warm mantle. We interpret this structure of the transition zone as resulting from the ponding of a mantle plume (possibly the deep-mantle African Superplume) at the base of the transition zone, which then drives localized thermal upwellings that disrupt the top of the transition zone and extend to shallow mantle depths beneath the rift in Kenya and northern Tanzania

Seasonal and spatial variations in the ocean-coupled ambient wavefield of the Ross Ice Shelf

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Baker, M. G., Aster, R. C., Anthony, R. E., Chaput, J., Wiens, D. A., Nyblade, A., Bromirski, P. D., Gerstoft, P., & Stephen, R. A. Seasonal and spatial variations in the ocean-coupled ambient wavefield of the Ross Ice Shelf. Journal of Glaciology, 65(254), (2019): 912-925, doi:10.1017/jog.2019.64.The Ross Ice Shelf (RIS) is host to a broadband, multimode seismic wavefield that is excited in response to atmospheric, oceanic and solid Earth source processes. A 34-station broadband seismographic network installed on the RIS from late 2014 through early 2017 produced continuous vibrational observations of Earth's largest ice shelf at both floating and grounded locations. We characterize temporal and spatial variations in broadband ambient wavefield power, with a focus on period bands associated with primary (10–20 s) and secondary (5–10 s) microseism signals, and an oceanic source process near the ice front (0.4–4.0 s). Horizontal component signals on floating stations overwhelmingly reflect oceanic excitations year-round due to near-complete isolation from solid Earth shear waves. The spectrum at all periods is shown to be strongly modulated by the concentration of sea ice near the ice shelf front. Contiguous and extensive sea ice damps ocean wave coupling sufficiently so that wintertime background levels can approach or surpass those of land-sited stations in Antarctica.This research was supported by NSF grants PLR-1142518, 1141916, 1142126, 1246151 and 1246416. JC was additionally supported by Yates funds in the Colorado State University Department of Mathematics. PDB also received support from the California Department of Parks and Recreation, Division of Boating and Waterways under contract 11-106-107. We thank Reinhard Flick and Patrick Shore for their support during field work, Tom Bolmer in locating stations and preparing maps, and the US Antarctic Program for logistical support. The seismic instruments were provided by the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech. Data collected are available through the IRIS Data Management Center under RIS and DRIS network code XH. The PSD-PDFs presented in this study were processed with the IRIS Noise Tool Kit (Bahavar and others, 2013). The facilities of the IRIS Consortium are supported by the National Science Foundation under Cooperative Agreement EAR-1261681 and the DOE National Nuclear Security Administration. The authors appreciate the support of the University of Wisconsin-Madison Automatic Weather Station Program for the data set, data display and information; funded under NSF grant number ANT-1543305. The Ross Ice Shelf profiles were generated using the Antarctic Mapping Tools (Greene and others, 2017). Regional maps were generated with the Generic Mapping Tools (Wessel and Smith, 1998). Topography and bathymetry data for all maps in this study were sourced from the National Geophysical Data Center ETOPO1 Global Relief Model (doi:10.7289/V5C8276M). We thank two anonymous reviewers for suggestions on the scope and organization of this paper

Burden and outcome of HIV infection and other morbidities in health care workers attending an Occupational Health Program at the Provincial Hospital of Tete, Mozambique.

Objectives  To investigate the burden and outcome of HIV infection and other morbidities amongst a Mozambican hospital staff. Methods  Within an occupational health service set up in April 2008 in the provincial hospital of Tete, Mozambique, we offered to all staff members an initial clinical, laboratory and radiological screening and followed them up prospectively until April 2010. Results  A total of 47.5% of 423 health workers attended the program. The cohort (female-to-male ratio: 2.2; mean age: 39 years) consisted mostly of auxiliary staff (43%) and nurses (29.8%). At initial screening, 71% were asymptomatic. HIV infection (28.4%) and tuberculosis (TB) (21%) were the main reported antecedent illnesses. Laboratory screening revealed anaemia (haemoglobin level <10 mg/dl) in 9% participants, abnormal liver enzymes in 23.9% and a reactive non-treponemal syphilis test in 5%. Of 145 performed chest X-rays, 13% showed abnormalities. All 113 health workers not recently tested for HIV were screened, and 31 were newly diagnosed with HIV infection (resulting in an overall HIV prevalence of 43.8%). Nine cases of TB were diagnosed at screening/during follow-up. In April 2010, all but one of the participants were alive. All HIV-infected health workers under antiretroviral therapy were actively followed-up. Conclusion  Serious conditions were frequently diagnosed in health workers, in particular HIV infection. Mid-term outcome was favourable within this program. Creation of screening and care services dedicated to caregivers should be of highest priority in similar African settings

Upper Mantle Earth Structure in Africa From Full-Wave Ambient Noise Tomography

Our understanding of the tectonic development of the African continent and the interplay between its geological provinces is hindered by unevenly distributed seismic instrumentation. In order to better understand the continent, we used long-period ambient noise full-waveform tomography on data collected from 186 broadband seismic stations throughout Africa and surrounding regions to better image the upper mantle structure. We extracted empirical Green\u27s functions from ambient seismic noise using a frequency-time normalization method and retrieved coherent signal at periods of 7–340 s. We simulated wave propagation through a heterogeneous Earth using a spherical finite-difference approach to obtain synthetic waveforms, measured the misfit as phase delay between the data and synthetics, calculated numerical sensitivity kernels using the scattering integral approach, and iteratively inverted for structure. The resulting images of isotropic, shear wave speed for the continent reveal segmented, low-velocity upper mantle beneath the highly magmatic northern and eastern sections of the East African Rift System (EARS). In the southern and western sections, high-velocity upper mantle dominates, and distinct, low-velocity anomalies are restricted to regions of current volcanism. At deeper depths, the southern and western EARS transition to low velocities. In addition to the EARS, several low-velocity anomalies are scattered through the shallow upper mantle beneath Angola and North Africa, and some of these low-velocity anomalies may be connected to a deeper feature. Distinct upper mantle high-velocity anomalies are imaged throughout the continent and suggest multiple cratonic roots within the Congo region and possible cratonic roots within the Sahara Metacraton

Velocity structure and lithospheric age of the Gamburtsev Subglacial Mountains

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月16日（水） 国立国語研究

Drug-related stigma and access to care among people who inject drugs in Vietnam.

Introduction and aimsThere are considerable challenges faced by people with a history of injecting drug use (PWID) in Vietnam, including drug-related stigma and lack of access to healthcare. Seeking and utilising healthcare, as well as harm reduction programs for PWID, are often hampered by drug-related stigma. This study aimed to examine the impacts of drug-related stigma on access to care and utilisation of harm reduction programs among PWID in Vietnam.Design and methodsA cross-sectional study was conducted in two provinces in Vietnam, Phú Thọ and Vinh Phúc. The study participants completed the survey by using Audio Computer-Assisted Self-Interview between late 2014 and early 2015. Linear multiple regression models and logistic regression models were used to assess the relationship among drug-related stigma, access to care and utilisation of harm reduction programs, including methadone maintenance treatment (MMT) and needle exchange programs (NEP).ResultsA total of 900 PWID participated in this study. Drug-related stigma was significantly associated with lower level of access to care, but not with utilisation of MMT or NEP. Older age was positively associated with higher levels of access to care. Levels of education were positively correlated with access to care, as well as utilisation of MMT and NEP.Discussion and conclusionsThis study underscores the need for future interventions to reduce drug-related stigma in society and in health-care settings to improve PWID's utilisation of care services. Special attention should be paid to younger PWID and those with lower levels of education