The HIV Anticaptory Saving Motive: An Empirical Analysis in South Africa

This paper studies the effect of the HIV/AIDS epidemic on saving behaviour. Two important characteristics of HIV result in opposing forces on savings: mortality increases, which reduces savings, and long-term illness risk increases, which enhances savings. We use a two period life-cycle model with uncertain lifetime including perceived HIV contamination risk to illustrate both the opposing effects of the HIV epidemic on individual savings and test the predictions of our model with data obtained from an economic experiment with real monetary incentives performed in South Africa. The empirical results show that increased mortality decreases the amount of savings and that having a high perception of HIV contamination risk increases savings. The latter effect confirms the HIV anticipatory saving hypothesis.HIV/AIDS;saving behavior;illness risk;mortality;life-cycle model;time preferences

HIV/AIDS Contamination Risk, Savings and the Welfare Effects of Diagnostic Testing

This paper models the effect of a HIV/AIDS epidemic on saving behavior and studies the welfare effects of testing for HIV. The model specifies a utility function that includes both regular consumption, and medical expenditures. Medical expenditures generate more utility if individuals are HIV infected, but they are only able to purchase the optimal medical consumption after being tested HIV positive. The paper describes different effects on aggregate savings according to different stages of the epidemic. We show that the HIV epidemic decreases savings if especially young individuals are (perceived to be) affected by the virus, but may increase savings if individuals perceive a sizable probability of getting infected later in life. By the same token, the welfare effects of testing young individuals differs greatly from the welfare effects of testing older individuals, the reason being that the savings responses to testing differ according to whether old or young individuals are tested.saving behavior;perceived risk;HIV/AIDS;HIV testing;mortality;life-cycle model

Scaling gridded river networks for macroscale hydrology: Development, analysis, and control of error

A simple and robust river network scaling algorithm (NSA) is presented to rescale fine‐resolution networks to any coarser resolution. The algorithm was tested over the Danube River basin and the European continent. Coarse‐resolution networks, at 2.5, 5, 10, and 30 min resolutions, were derived from higher‐resolution gridded networks using NSA and geomorphometric attributes, such as river order, shape index, and width function. These parameters were calculated and compared at each resolution. Simple scaling relationships were found to predict decreasing river lengths with coarser‐resolution data. This relationship can be used to correct river length as a function of grid resolution. The length‐corrected width functions of the major river basins in Europe were compared at different resolutions to assess river network performance. The discretization error in representing basin area and river lengths at coarser resolutions were analyzed, and simple relationships were found to calculate the minimum number of grid cells needed to maintain the catchment area and length within a desired level of accuracy. This relationship among geomorphological characteristics, such as shape index and width function (derived from gridded networks at different resolutions), suggests that a minimum of 200–300 grid cells is necessary to maintain the geomorphological characteristics of the river networks with sufficient accuracy

Widespread decline in hydrological monitoring threatens Pan‐Arctic Research

Operational river discharge monitoring is declining in both North America and Eurasia. This problem is especially severe in the Far East of Siberia and the province of Ontario, where 73% and 67% of river gauges were closed between 1986 and 1999, respectively. These reductions will greatly affect our ability to study variations in and alterations to the pan‐Arctic hydrological cycle

Global system of rivers: Its role in organizing continental land mass and defining land‐to‐ocean linkages

The spatial organization of the Earth\u27s land mass is analyzed using a simulated topological network (STN‐30p) representing potential flow pathways across the entire nonglacierized surface of the globe at 30‐min (longitude × latitude) spatial resolution. We discuss a semiautomated procedure to develop this topology combining digital elevation models and manual network editing. STN‐30p was verified against several independent sources including map products and drainage basin statistics, although we found substantial inconsistency within the extant literature itself. A broad suite of diagnostics is offered that quantitatively describes individual grid cells, river segments, and complete drainage systems spanning orders 1 through 6 based on the Strahler classification scheme. Continental and global‐scale summaries of key STN‐30p attributes are given. Summaries are also presented which distinguish basins that potentially deliver discharge to an ocean (exorheic) from those that potentially empty into an internal receiving body (endorheic). A total of 59,122 individual grid cells constitutes the global nonglacierized land mass. At 30‐min spatial resolution, the cells are organized into 33,251 distinct river segments which define 6152 drainage basins. A global total of 133.1 × 106 km2 bear STN‐SOp flow paths with a total length of 3.24 × 106 km. The organization of river networks has an important role in linking land mass to ocean. From a continental perspective, low‐order river segments (orders 1‐3) drain the largest fraction of land (90%) and thus constitute a primary source area for runoff and constituents. From an oceanic perspective, however, the small number (n=101) of large drainage systems (orders 4‐6) predominates; draining 65% of global land area and subsuming a large fraction of the otherwise spatially remote low‐order rivers. Along river corridors, only 10% of land mass is within 100 km of a coastline, 25% is within 250 km, and 50% is within 750 km. The global mean distance to river mouth is 1050 km with individual continental values from 460 to 1340 km. The Mediterranean/Black Sea and Arctic Ocean are the most land‐dominated of all oceans with land:ocean area ratios of 4.4 and 1.2, respectively; remaining oceans show ratios from 0.55 to 0.13. We discuss limitations of the STN‐30p together with its potential role in future global change studies. STN‐30p is geographically linked to several hundred river discharge and chemistry monitoring stations to provide a framework for calibrating and validating macroscale hydrology and biogeochemical flux models

HIV/AIDS, Risk and Intertemporal Choice.

Her experimental data also show that unprotected sexual behavior appears to be partly an economic decision explicable by individual risk and time preferences. Therefore education on prevention methods alone is not sufficient to prevent the further spread of HIV. Informing individuals on both the actual infection risk and the actual economic costs, e.g. the reduced future consumption possibilities, will further reduce unprotected sexual behavior and stimulate anticipatory savings. The latter will increase the coping possibilities of individuals that do contract the virus, improving social welfare in the countries hardest hit.

Assessment of contemporary Arctic river runoff based on observational discharge records

We describe the contemporary hydrography of the pan‐Arctic land area draining into the Arctic Ocean, northern Bering Sea, and Hudson Bay on the basis of observational records of river discharge and computed runoff. The Regional Arctic Hydrographic Network data set, R‐ArcticNET, is presented, which is based on 3754 recording stations drawn from Russian, Canadian, European, and U.S. archives. R‐ArcticNET represents the single largest data compendium of observed discharge in the Arctic. Approximately 73% of the nonglaciated area of the pan‐Arctic is monitored by at least one river discharge gage giving a mean gage density of 168 gages per 106 km2. Average annual runoff is 212 mm yr−1 with approximately 60% of the river discharge occurring from April to July. Gridded runoff surfaces are generated for the gaged portion of the pan‐Arctic region to investigate global change signals. Siberia and Alaska showed increases in winter runoff during the 1980s relative to the 1960s and 1970s during annual and seasonal periods. These changes are consistent with observations of change in the climatology of the region. Western Canada experienced decreased spring and summer runoff

Additions to the Vascular Plant Type Collection of the Ohio State University Herbarium

Author Institution: Department of Botany, The Ohio State UniversityFifty-three type specimens of vascular plants are reported as additions to the type collection of The Ohio State University Herbarium, bringing the total number to 276. These include both recent acquisitions and newly recognized type material already in the collection. For each specimen, the name of the taxon, collection data, kind of type specimen, and source are provided