Muskrats as a bellwether of a drying delta.

Wetlands worldwide are under threat from anthropogenic impacts. In large protected North American areas such as Yellowstone and Wood Buffalo National Parks, aquatic habitats are disappearing and wetland-dependent fauna are in decline. Here we investigate population dynamics of an indicator species in Canada's Peace-Athabasca Delta ("the delta"), a World Heritage Site.

A coupled human-natural system analysis of freshwater security under climate and population change.

Limited water availability, population growth, and climate change have resulted in freshwater crises in many countries. Jordan's situation is emblematic, compounded by conflict-induced population shocks. Integrating knowledge across hydrology, climatology, agriculture, political science, geography, and economics, we present the Jordan Water Model, a nationwide coupled human-natural-engineered systems model that is used to evaluate Jordan's freshwater security under climate and socioeconomic changes.

Controlling Arsenic Mobilization during Managed Aquifer Recharge: The Role of Sediment Heterogeneity.

Managed aquifer recharge (MAR) enhances freshwater security and augments local groundwater supplies. However, geochemical and hydrological shifts during MAR can release toxic, geogenic contaminants from sediments to groundwater, threatening the viability of MAR as a water management strategy. Using reactive transport modeling coupled with aquifer analyses and measured water chemistry, we investigate the causal mechanisms of arsenic release during MAR via injection in the Orange County Groundwater Basin.

Broad approaches to cholera control in Asia: Water, sanitation and handwashing.

Cholera has been eliminated as a public health problem in high-income countries that have implemented sanitation system separating the community's fecal waste from their drinking water and food supply. These expensive, highly-engineered systems, first developed in London over 150 years ago, have not reached low-income high-risk communities across Asia. Barriers to their implementation in communities at highest risk for cholera include the high capital and operating costs for this technological approach, limited capacity and perverse incentives of local governments, and a decreasing availability of water.

Increasing drought in Jordan: Climate change and cascading Syrian land-use impacts on reducing transboundary flow.

In countries where severe drought is an anticipated effect of climate change and in those that heavily depend on upstream nations for fresh water, the effect of drier conditions and consequent changes in the transboundary streamflow regime induced by anthropogenic interventions and disasters leads to uncertainty in regional water security. As a case in point, we analyze Jordan's surface water resources and agricultural water demand through 2100, considering the combined impacts of climate change and land-use change driven by the Syrian conflict. We use bias-corrected regional climate simulations as input to high-resolution hydrologic models to assess three drought types: meteorological (rainfall decrease), agricultural (soil moisture deficit), and hydrologic (streamflow decline) under future scenarios.

Impact of the Syrian refugee crisis on land use and transboundary freshwater resources.

Since 2013, hundreds of thousands of refugees have migrated southward to Jordan to escape the Syrian civil war that began in mid-2011. Evaluating impacts of conflict and migration on land use and transboundary water resources in an active war zone remains a challenge. However, spatial and statistical analyses of satellite imagery for the recent period of Syrian refugee mass migration provide evidence of rapid changes in land use, water use, and water management in the Yarmouk-Jordan river watershed shared by Syria, Jordan, and Israel.

Arsenic in the multi-aquifer system of the Mekong Delta, Vietnam: analysis of large-scale spatial trends and controlling factors.

Groundwater exploitation is rising in the Mekong Delta, Vietnam, potentially exacerbating arsenic contamination from natural sources. We investigate trends and controls on contamination patterns throughout the Delta's multi-aquifer system as observed in a spatially exhaustive data set of arsenic measured in >40,000 wells, 10.5% of which exceed the WHO drinking water standard for arsenic (10 μg/L).

Hydrological controls on methylmercury distribution and flux in a tidal marsh.

The San Francisco Estuary, California, contains mercury (Hg) contamination originating from historical regional gold and Hg mining operations. We measured hydrological and geochemical variables in a tidal marsh of the Palo Alto Baylands Nature Preserve to determine the sources, location, and magnitude of hydrological fluxes of methylmercury (MeHg), a bioavailable Hg species of ecological and health concern. Based on measured concentrations and detailed finite-element simulation of coupled surface water and saturated-unsaturated groundwater flow, we found pore water MeHg was concentrated in unsaturated pockets that persisted over tidal cycles.

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence.

Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km(2)) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene-Miocene-age aquifers, where nearly 900 wells at depths of 200-500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988.

Peak oil demand: the role of fuel efficiency and alternative fuels in a global oil production decline.

Some argue that peak conventional oil production is imminent due to physical resource scarcity. We examine the alternative possibility of reduced oil use due to improved efficiency and oil substitution. Our model uses historical relationships to project future demand for (a) transport services, (b) all liquid fuels, and (c) substitution with alternative energy carriers, including electricity.

Earthquake triggering and large-scale geologic storage of carbon dioxide.

Despite its enormous cost, large-scale carbon capture and storage (CCS) is considered a viable strategy for significantly reducing CO(2) emissions associated with coal-based electrical power generation and other industrial sources of CO(2) [Intergovernmental Panel on Climate Change (2005) IPCC Special Report on Carbon Dioxide Capture and Storage. Prepared by Working Group III of the Intergovernmental Panel on Climate Change, eds Metz B, et al. (Cambridge Univ Press, Cambridge, UK); Szulczewski ML, et al.

Russell body gastritis in an HIV positive patient: case report and review of literature.

Russell body gastritis is characterized by accumulation of plasma cells, filled with Russell bodies, in the gastric mucosa. Twelve cases have been reported in the English language medical literature. Its association with Helicobacter pylori gastritis or immunosuppression is known.

Lessons learned from 25 years of research at the MADE site.

Field studies at well-instrumented research sites have provided extensive data sets and important insights essential for development and testing of transport theories and mathematical models. This paper provides an overview of over 25 years of research and lessons learned at one of such field research sites on the Columbus Air Force Base in Mississippi, commonly known as the Macrodispersion Experiment (MADE) site. Since the mid-1980s, field data from the MADE site have been used extensively by researchers around the world to explore complex contaminant transport phenomena in highly heterogeneous porous media.

Investigation of small-scale preferential flow with a forced-gradient tracer test.

A new tracer experiment (referred to as MADE-5) was conducted at the well-known Macrodispersion Experiment (MADE) site to investigate the influence of small-scale mass-transfer and dispersion processes on well-to-well transport. The test was performed under dipole forced-gradient flow conditions and concentrations were monitored in an extraction well and in two multilevel sampler (MLS) wells located at 6, 1.5, and 3.

Processes controlling the thermal regime of saltmarsh channel beds.

Spatially and temporally continuous temperature measurements were collected over 32 h using a fiber-optic distributed temperature sensing (DTS) system deployed along 330 m of two intertidal saltmarsh channel beds in northern California. Measured temperature gradients imparted ecosystem-scale structure to the saltmarsh tidal channel thermal regime, which was punctuated by potential warm and cold refugia. Anomalous bed temperatures of 2-4 degrees C occurred throughout the 1.

Quantifying stream-aquifer interactions through the analysis of remotely sensed thermographic profiles and in situ temperature histories.

The interaction between surface and subsurface waters through hyporheic exchange and baseflow is critical to maintaining ecological health in streams. During warm periods, groundwater-surface water interactions have two primary effects on stream temperature: (1) cool groundwater discharging as baseflow lowers stream temperature and (2) hyporheic exchange buffers diurnal stream temperature variations. We demonstrate, for the first time, how high-resolution, remotely sensed forward-looking infrared (FLIR) images and instream temperature data can be used to quantify detailed spatial patterns of groundwater discharge to a 1.

Effective permeability of porous media containing branching channel networks.

We study the effective permeability of two-dimensional binary systems characterized by a network of branching channels embedded in a uniform matrix material. Channels are assigned a higher permeability than the surrounding matrix and, therefore, serve as preferential pathways for fluid migration. The channel networks are constructed using a nonlooping invasion percolation model.

Field evaluation of in situ source reduction of trichloroethylene in groundwater using bioenhanced in-well vapor stripping.

Two technologies in combination, cometabolic bioremediation and in-well vapor stripping, were applied to reduce trichloroethylene (TCE) concentrations in groundwater at a contaminant source area without the need to pump contaminated groundwater to the surface for treatment. The vapor-stripping well reduced source TCE concentrations (as high as 6-9 mg/L) by over 95%. Effluent from the well then flowed to two bioremediation wells, where additional reductions of approximately 60% were achieved.

Transcriptional responses of human epidermal keratinocytes to Oncostatin-M.

Oncostatin-M (OsM) plays an important role in inflammatory and oncogenic processes in skin, including psoriasis and Kaposi sarcoma. However, the molecular responses to OsM in keratinocytes have not been explored in depth. Here we show the results of transcriptional profiling in OsM-treated primary human epidermal keratinocytes, using high-density DNA microarrays.

Gastric toxoplasmosis as the presentation of acquired immunodeficiency syndrome.

We report a case of a 39-year-old West African man with unknown human immunodeficiency virus status diagnosed with gastric toxoplasmosis as the presenting manifestation of acquired immunodeficiency syndrome. Toxoplasma gondii is common in severely immunosuppressed patients and most frequently involves the central nervous system, followed by the eye, myocardium and skeletal muscle, lungs, bone marrow, and peripheral blood. For unclear reasons, gastrointestinal involvement is exceedingly rare and occurs in the context of severe immunosuppression and disseminated disease.

Analysis of solute transport in flow fields influenced by preferential flowpaths at the decimeter scale.

Several recent studies at the Macrodispersion Experiment (MADE) site in Columbus, Mississippi, have indicated that the relative preferential flowpaths and flow barriers resulting from decimeter-scale aquifer heterogeneities appear to have a dominant effect on plume-scale solute transport. Numerical experiments are thus conducted in this study to explore the key characteristics of solute transport in two-dimensional flow fields influenced by decimeter-scale preferential flowpaths. A hypothetical but geologically plausible network of 10 cm wide channels of high hydraulic conductivity is used to represent the relative preferential flowpaths embedded in an otherwise homogeneous aquifer.