HIV And The Need For A Voluntarist Approach

After a decade of fighting AIDS, the public health community has come to recognize that strategies to combat the infection must be premised on voluntarism and not on coercion. Attempts to combat AIDS with coercive public health strategies stem from a desire to force AIDS into an ill-fitting traditional disease-response framework, overlooking the differences between HIV and other sexually transmitted diseases, including the limitations in available treatment modalities for HIV. A return to such a cramped, narrowly-medicalized view of the AIDS epidemic has enormous social implications and a coercive strategy would frustrate efforts to stem the spread of the disease. Further, such strategies would hamper the willingness of those in need of medical care and education to benefit from existing programs. This essay explores some of the possible explanations for the apparent erosion of the voluntarist consensus and calls for a return to such a voluntarist approach through effective health care and education efforts

HIV And The Need For A Voluntarist Approach

After a decade of fighting AIDS, the public health community has come to recognize that strategies to combat the infection must be premised on voluntarism and not on coercion. Attempts to combat AIDS with coercive public health strategies stem from a desire to force AIDS into an ill-fitting traditional disease-response framework, overlooking the differences between HIV and other sexually transmitted diseases, including the limitations in available treatment modalities for HIV. A return to such a cramped, narrowly-medicalized view of the AIDS epidemic has enormous social implications and a coercive strategy would frustrate efforts to stem the spread of the disease. Further, such strategies would hamper the willingness of those in need of medical care and education to benefit from existing programs. This essay explores some of the possible explanations for the apparent erosion of the voluntarist consensus and calls for a return to such a voluntarist approach through effective health care and education efforts

What do we need for robust and quantitative health impact assessment?

Health impact assessment (HIA) aims to make the health consequences of decisions explicit. Decision-makers need to know that the conclusions of HIA are robust. Quantified estimates of potential health impacts may be more influential but there are a number of concerns. First, not everything that can be quantified is important. Second, not everything that is being quantified at present should be, if this cannot be done robustly. Finally, not everything that is important can be quantified; rigorous qualitative HIA will still be needed for a thorough assessment. This paper presents the first published attempt to provide practical guidance on what is required to perform robust, quantitative HIA. Initial steps include profiling the affected populations, obtaining evidence from for postulated impacts, and determining how differences in subgoups' exposures and suscepibilities affect impacts. Using epidemiological evidence for HIA is different from carrying out a new study. Key steps in quantifying impacts are mapping the causal pathway, selecting appropriate outcome measures and selecting or developing a statistical model. Evidence from different sources is needed. For many health impacts, evidence of an effect may be scarce and estimates of the size and nature of the relationship may be inadequate. Assumptions and uncertainties must therefore be explicit. Modelled data can sometimes be tested against empirical data but sensitivity analyses are crucial. When scientific problems occur, discontinuing the study is not an option, as HIA is usually intended to inform real decisions. Both qualitative and quantitative elements of HIA must be performed robustly to be of value

Radiative Energetics of Mineral Dust Aerosols from Ground-Based Measurements

Airborne dust aerosols worldwide contribute a significant part to air quality problems and, to some extent, regional climatic issues (e.g., radiative forcing, hydrological cycle, and primary biological productivity in oceans). Evaluating the direct solar radiative effect of dust aerosols is relatively straightforward due in part to the relatively large SIN ratio in broadband irradiance measurements. The longwave (LW) impact, on the other hand, is rather difficult to ascertain since the measured dust signal level (approx.10 W/sq m) is on the same order as the instrumental uncertainties. Although the magnitude of the LW impact is much smaller than that of the shortwave (SW), it can still have a noticeable influence on the energy distribution of Earth-atmosphere system, particularly due to the strong light-absorptive properties commonly found in many terrestrial minerals. The current effort is part of an ongoing research study to perform a global assessment of dust direct aerosol radiative effects (DARE) during major field deployments of key dust source regions worldwide. In this work we present results stemming from two previous field deployments: the 2006 NASA African Monsoon Multidisciplinary Activities and the 2008 Asian Monsoon Years, both utilizing NASA Goddard's mobile ground-based facility. The former study focused on transported Saharan dust at Sal (16.73degN, 22.93degW), Cape Verde along the west coast of Africa while the latter focused on Asian dust at Zhangye (39.082degN, 100.276degE), China near the source between the Taklimakan and Gobi deserts. Due to the compelling variability in spatial and temporal scale of dust properties during field experiments, a deterministic I-D radiative transfer model constrained by local measurements (i.e., spectral photometry/interferometry and lidar for physical/microphysical, mineralogy, and single-scattering properties) is employed to evaluate dust's local instantaneous SW/LW DARE both at the surface and at the top of the atmosphere along with heating rate profiles for cloud-free atmospheres. In both dust cases the efficiency in the L W DARE is investigated and its significance is compared relative to that of diurnally SW

Dissolved organic matter in the global ocean: A primer

Marine dissolved organic matter (DOM) holds ~660 billion metric tons of carbon, making it one of Earth’s major carbon reservoirs that is exchangeable with the atmosphere on annual to millennial time scales. The global ocean scale dynamics of the pool have become better illuminated over the past few decades, and those are very briefly described here. What is still far from understood is the dynamical control on this pool at the molecular level; in the case of this Special Issue, the role of microgels is poorly known. This manuscript provides the global context of a large pool of marine DOM upon which those missing insights can be built

Development of White Spruce Tree Islands in the Shrub Zone of the Forest-tundra

The growth of four white spruce (Picea glauca) clonal islands ranging in age from ca. 98 years to more than 400 years was investigated in the shrub zone of the forest-tundra east of Churchill, Manitoba, Canada. The elongation of 20 similar-aged stems in each of the three youngest islands was monitored during 1988 and 1989, along with ground and air temperatures. Stems in the younger islands showed a more flexible response to both daily and annual variation in temperature. Younger islands showed faster recovery from frost events during elongation and longer periods of elongation in cooler years. Early spring warming that caused snowmelt to occur before the growing season appeared to result in moisture stress later in the period of elongation. In stems of spruce shrub, the branches are concentrated near ground level because growth is slow and adventitious buds develop on the stem after repeated loss of stem terminals through snow abrasion. In young trees, shading and increased moisture from trapped snow coincide with feather moss establishment and a deep active layer, resulting in higher ground temperatures and faster tree growth. It is during this early period of development that a tree may be best able to develop an erect stem. In later development, the lowest branches of trees become appressed, grow roots, and become second-order stems, and this process continues outward from the central stem. In older tree islands, peat accumulation and needle abrasion can lead to conditions less favourable for growth and maintenance of needles. Consequently, the canopy may thin, which reduces its ability to trap snow. When snow cover is reduced, lichen-heath establishes and permafrost intrudes into the mound. Subsequent growth of the secondary stems on the mound may be too slow to enable successful development of an erect stem. Thus, island development is largely dependent on changing ground temperatures, which become colder as peat accumulates and frost heaving elevates the mound. Warm spring and summer conditions appear to lead to unfavourable conditions for tree islands.On a étudié la croissance de quatre îlots de clones d'épinettes blanches (Picea glauca) dont l'âge allait d'environ 98 à plus de 400 ans, situés dans la zone de végétation arbustive de la toundra forestière, à l'est de Churchill (Manitoba) au Canada. En 1988 et 1989, on a surveillé l'élongation de vingt tiges du même âge dans chacun des trois plus jeunes îlots ainsi que la température du sol et celle de l'air. Les tiges des plus jeunes îlots réagissaient avec plus de souplesse aux variations de température quotidienne comme annuelle. Les îlots les plus jeunes affichaient une aptitude à la réparation plus rapide suite à des périodes de gel durant l'élongation, ainsi que des périodes d'élongation plus longues durant les années plus fraîches. Un réchauffement printanier précoce provoquant la fonte des neiges avant la saison de croissance semblait résulter en une tension hydrique plus tard durant la période d'élongation. Sur les troncs d'épinettes arbustives, les branches sont concentrées près du niveau du sol en raison de la lenteur de la croissance et du développement de bourgeons adventifs sur le tronc après la perte répétée des terminaisons de tiges causée par l'abrasion nivale. Chez les jeunes arbres, l'ombrage et l'augmentation d'humidité provenant de la neige emprisonnée coïncident avec l'établissement d'hypnacées et une épaisse couche active, ce qui résulte en des températures au sol plus élevées et une croissance des arbres plus rapide. C'est durant cette phase initiale de développement qu'un arbre se révèle capable de développer un tronc droit. Au cours de la croissance ultérieure, les branches les plus basses deviennent appressées, prennent racine, devenant troncs secondaires, et le processus se poursuit en rayonnant à partir du tronc central. Dans les îlots d'arbres plus vieux, l'accumulation de tourbe et l'abrasion des aiguilles peuvent aboutir à des conditions moins favorables pour la croissance et le maintien des aiguilles. Il en résulte que le houppier peut s'éclaircir, ce qui réduit sa capacité à emprisonner la neige. Quand le couvert nival est réduit, il s'établit une bruyère à lichens et le pergélisol pénètre dans le monticule. Il peut arriver que la croissance ultérieure des tiges secondaires sur le monticule soit trop lente pour permettre le développement d'un tronc droit. Le développement d'un îlot est donc en grande partie dépendant de la variabilité de la température au sol, qui baisse à mesure que s'accumule la tourbe et que le gonflement dû au gel soulève le monticule. Il semble qu'un printemps chaud et la saison estivale résultent en des conditions défavorables pour les îlots arbustifs

Mechanisms controlling vertical variability of subsurface chlorophyll maxima in a mode-water eddy

An intense subsurface chlorophyll enhancement was found repeatedly within the core of a mode-water eddy during a 2-month period. Two controls on chlorophyll concentrations in this deep chlorophyll maximum (DCM) layer are noted: chlorophyll concentration is controlled by nutrients at low nutrient concentrations and by light when nutrients are saturating. To synthesize these results, a simple one-dimensional nutrient-phytoplankton model is developed by including the effects of phytoplankton self-shading for light attenuation, depth-dependent phytoplankton specific loss, and density-associated nutrient fluctuation in the deep layer. The model is parameterized using eddy data including not only vertical diffusivity, sinking velocity, and chlorophyll-to-carbon ratios, but also rates of phytoplankton growth and nutrient regeneration. Our results suggest that the observed DCM variability is controlled by nutrient-light interaction leading to a change of phytoplankton physiology and hence vertical enrichment of chlorophyll within the core of the stratified eddy. Further theoretical analyses indicate that variation of nutrient and light availability in the DCM layer of the eddy core is largely driven by change of the vertical nutrient fluxes as a result of isopycnal motions in the deep layer, which is also subject to influences by processes including vertical mixing, particle sinking, and nutrient regeneration

Respiratory hospital admission risk near large composting facilities

AbstractBackgroundLarge-scale composting can release bioaerosols in elevated quantities, but there are few studies of health effects on nearby communities.MethodsA cross-sectional ecological small area design was used to examine risk of respiratory hospital admissions within 2500m of all 148 English large-scale composting facilities in 2008–10. Statistical analyses used a random intercept Poisson regression model at Census Output Area (COA) level (mean population 310). Models were adjusted for age, sex, deprivation and tobacco sales.ResultsAnalysing 34,963 respiratory hospital admissions in 4656 COAs within 250–2500m of a site, there were no significant trends using pre-defined distance bands of >250–750m, >750–1500m and >1500–2500m. Using a continuous measure of distance, there was a small non-statistically significant (p=0.054) association with total respiratory admissions corresponding to a 1.5% (95% CI: 0.0–2.9%) decrease in risk if moving from 251m to 501m. There were no significant associations for subgroups of respiratory infections, asthma or chronic obstructive pulmonary disease.ConclusionThis national study does not provide evidence for increased risks of respiratory hospital admissions in those living beyond 250m of an outdoor composting area perimeter. Further work using better measures of exposure and exploring associations with symptoms and disease prevalence, especially in vulnerable groups, is recommended to support regulatory approaches

Organic nitrogen in aerosols and precipitation at Barbados and Miami: Implications regarding sources, transport and deposition to the western subtropical North Atlantic

The deposition of anthropogenic nitrogen (N) species is believed to have a significant impact on the oligotrophic North Atlantic, but the magnitude of ecological effects remains uncertain because the deposition of water soluble organic N (WSON) is poorly quantified. Here we present measurements of water soluble inorganic N (WSIN) and WSON in aerosol and rain at two subtropical North Atlantic time series sites: Barbados and Miami. WSON total deposition rates ranged from 17.9 mmol m−2 yr−1 to 49.6 mmol m−2 yr−1, contributing on average only 6–14% of total N deposition, less than half the poorly constrained global average which is typically cited as 30%. On an event basis, biomass burning and dust events yielded the largest concentrations of WSON. However, biomass burning was relatively infrequent and highly variable in composition, and much of the organic N associated with dust appeared to be externally adsorbed from pollution sources. Conversely, in Miami pollution made relatively small contributions of WSON on an event basis, but impacts were relatively frequent, making pollution one of the largest sources of WSON during the year. The largest contributor to WSON was volatile basic organic N (VBON) species, which were present at concentrations 1–2 times higher than particulate WSON. Despite VBON inputs, samples associated with pollution-source trajectories yielded much more inorganic N than WSON. Consequently, we would expect that in the future as anthropogenic N emissions increase, inorganic nitrogen will remain the dominant form of N that is deposited to the western North Atlantic