Arash Sharifi

Geochemical fingerprinting of trans-Atlantic African dust based on radiogenic Sr-Nd-Hf isotopes and rare earth element anomalies

Mineral dust is an important component of Earth’s climate system and biogeochemical cycles on a global scale. In order to understand the relationship between climate processes in the source areas and the properties of aerosols at distant receptor sites, we must be able to identify the source provenance of dust. Here we present a multiproxy study that characterizes the temporal variability in the geochemical composition of long-range African dust (LRAD) collected between 2003 and 2011 in the trade winds on the Caribbean island of Barbados. We find systematic differences between Sr-Nd-Hf isotopic composition and rare earth element anomalies of individual dust events and evidence of seasonal shifts in dust source activity and transport. These results indicate that coherent geochemical source signatures of LRAD can be preserved even after transport across thousands of kilometers. We investigated the possibility of identifying the potential source areas through comparisons with literature data. However, these data are almost entirely based on measurements of soil and sediment samples; this could lead to biases because of soil-aerosol particle size and composition differences. Nonetheless, our data suggest that many samples are linked to sources in Mali and sub-Saharan regions. Radiogenic Nd-Hf composition of aerosols can potentially be a useful proxy to study the proximity of mineral dust sources to depositional sites. In order to establish firmer links between LRAD and dust source areas, however, we require much more data on the geochemical composition of aerosols from potential source areas in North Africa.

Climate Change and Respiratory Infections

The rate of global warming has accelerated over the past 50 years. Increasing surface temperature is melting glaciers and raising the sea level. More flooding, droughts, hurricanes, and heat waves are being reported. Accelerated changes in climate are already affecting human health, in part by altering the epidemiology of climate-sensitive pathogens. In particular, climate change may alter the incidence and severity of respiratory infections by affecting vectors and host immune responses. Certain respiratory infections, such as avian influenza and coccidioidomycosis, are occurring in locations previously unaffected, apparently because of global warming. Young children and older adults appear to be particularly vulnerable to rapid fluctuations in ambient temperature. For example, an increase in the incidence in childhood pneumonia in Australia has been associated with sharp temperature drops from one day to the next. Extreme weather events, such as heat waves, floods, major storms, drought, and wildfires, are also believed to change the incidence of respiratory infections. An outbreak of aspergillosis among Japanese survivors of the 2011 tsunami is one such well-documented example. Changes in temperature, precipitation, relative humidity, and air pollution influence viral activity and transmission. For example, in early 2000, an outbreak of Hantavirus respiratory disease was linked to a local increase in the rodent population, which in turn was attributed to a two- to threefold increase in rainfall before the outbreak. Climate-sensitive respiratory pathogens present challenges to respiratory health that may be far greater in the foreseeable future.

A Patient-Based Analysis of the Geographic Distribution of Mycobacterium avium complex, Mycobacterium abscessus, and Mycobacterium kansasii Infections in the United States

1. Patient data collection: The harmonized approach to data collection from the eight ICUs of the study by Hawkins et al allowed us to identify comanagement methods as a significant differentiating factor. Hospital size was not predictive. Generally speaking, current electronic systems and integration expertise allow the transfer of data through electronic interfaces and routinely simplify access to many forms of clinical information. Investment in these technologies and the proper training of critical care professionals may have prevented differences of electronic data transfer from being a detectable distinguishing factor for length of stay (LOS) outcomes in the study. 2. Authority to intervene: One of the important findings of the study by Hawkins et al is that it provides new information about how alternative approaches under the administrative control of the sponsoring or subscribing institutions affect outcomes and how costs compare in terms of LOS outcomes. 3. Collaboration between telemedicine and bedside ICUs: We strongly agree with the authors regarding the importance of collaborative relationships among ICU providers. We also agree that having staff work on both sides of the camera helps to promote these relationships. The use of two-way telemedicine systems that provide frequent communications, and which include patients who have the capacity to participate, is another effective way to form and develop these relationships. We respectfully point out that large comparative studies that included acuityadjusted outcomes have not identified the size of the ICU telemedicine program or number of supported ICUs as associated with meaningful differences of outcomes. Some studies have noted cost benefits to rural hospitals from reduced transfers and keeping patients closer to their homes. 4. Standardized practice evolution: We agree that the benefits associated with standardizing care can be difficult to achieve. The sharing and benchmarking of data and the reporting solutions that are part of larger programs have provided powerful tools for encouraging the adoption of standard best practices and measuring the impact of these changes on critical care outcomes.

Lung health in era of climate change and dust storms

&NA; Dust storms are strong winds which lead to particle exposure over extensive areas. These storms influence air quality on both a local and global scale which lead to both short and long‐term effects. The frequency of dust storms has been on the rise during the last decade. Forecasts suggest that their incidence will increase as a response to the effects of climate change and anthropogenic activities. Elderly people, young children, and individuals with chronic cardiopulmonary diseases are at the greatest risk for health effects of dust storms. A wide variety of infectious and non‐infectious diseases have been associated with dust exposure. Influenza A virus, pulmonary coccidioidomycosis, bacterial pneumonia, and meningococcal meningitis are a few examples of dust‐related infectious diseases. Among non‐infectious diseases, chronic obstructive pulmonary disease, asthma, sarcoidosis and pulmonary fibrosis have been associated with dust contact. Here, we review two molecular mechanisms of dust induced lung disease for asthma and sarcoidosis. We can also then further understand the mechanisms by which dust particles disturb airway epithelial and immune cells. HighlightsDust storms provide a vital role on Earth.The health impact of dust storms is principally determined by the particle size.The immune system plays a vital role in dust exposure.Association between dust and sarcoidosis has been proposed.Prevention and reduction of particle exposure is of paramount importance.

The Vanishing of Urmia Lake: A Geolimnological Perspective on the Hydrological Imbalance of the World’s Second Largest Hypersaline Lake

Urmia Lake was the second largest hypersaline lake in the world and the largest terminal lake in West Asia prior to catastrophically losing about 90% of its surface area over the last few decades as a consequence of anthropogenic disruptions. Urmia Lake fills in a tectonic depression in northwest Iran and draws water from an average catchment area of 52,000 km2 with 13 perennial and seasonal tributaries. The salinity of the lake varies from 140 to more than 220 g L−1 and is a function of the imbalance between water inflow and evaporation. Urmia Lake’s water supply has diminished significantly over the last three decades, leading to a drastic reduction in the lake’s surface area and has driven the salinity upwards of 380 g L−1. Through geochemical profiles of water and sediment samples from Urmia Lake, we examine the role of regional geology in the lake’s water chemistry and sedimentary evolution. Grain-size analysis of the siliciclastic fractions from core top samples reveals that the majority of the Urmia Lake bottom sediments consist of silt and clay-silt particles. This distribution transitions to sand and silty sand in the NW part of the lake, where felsic intrusive and metamorphic rocks are present. This distribution pattern, which is also manifested as changes in the lithogenic, conservative elements and the chemical index of alteration (CIA), is attributed to weathering resistance of heavy minerals. The distribution pattern of conservative elements (e.g., Ti, Zr, Si, Al), as well as redox-sensitive and mobile elements (e.g., Fe, K, Rb, Sr), in the clastic fraction of the lake’s sediments signifies the role of regional geology in defining the chemical signature of the Urmia Lake sediment. In addition, the total organic matter content shows significant correlation with the distribution pattern of clay in the sediment, potentially indicating stabilization of organic matter on fine-grained particles. The concentrations of selected heavy metals (Ni, Cr, V, and Hg) in the surficial sediments indicate that the middle and southeastern part of the lake were moderately contaminated with mercury at the time of the analysis. A significant finding is that prior to the catastrophic loss of water accelerated in the last three decades, the Urmia Lake brine was classified as Na + K-Cl-Mg-SO4 during the 1977–1997 period. The ionic signature of the Urmia brine has drastically shifted to Na + K-SO4-Mg-Cl by 2010 followed by a doubling of the total dissolved solid (TDS) content.