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Endocrinological research on wild animals inhabiting remote areas has been hampered by the need to store plasma samples at subzero temperatures. In an attempt to remedy this logistical issue, we here investigate the use of ethanol as an alternative to freezing for the preservation of steroid and indoleamine hormones in avian plasma. Known quantities of the steroids 5alpha-dihydrotestosterone (DHT), testosterone, 17beta-estradiol, corticosterone, and the indoleamine melatonin were added to a stripped pool of chicken plasma. Samples were either immediately frozen at -40 degrees C, or treated with pure ethanol. Ethanol-treated samples were either immediately frozen, or-to simulate storage conditions at various field locations-left sitting at room temperature for one to two months, or incubated at 36 degrees C for one month before all treatment groups were frozen at -40 degrees C. All samples were then analyzed by radioimmunoassay. For DHT and estradiol there were no differences among treatment groups suggesting that ethanol-treatment is as effective as immediate freezing in preserving plasma steroid concentrations. For testosterone, corticosterone and melatonin ethanol-treated samples differed significantly from immediately frozen samples suggesting that caution is needed when comparing absolute concentrations of hormones between samples preserved in different ways. However, differences among ethanol-treated samples in general were small, demonstrating the feasibility of this preservation method in the field at remote locations.

Endocrinological research on wild animals inhabiting remote areas has been hampered by the need to store plasma samples at subzero temperatures. In an attempt to remedy this logistical issue, we here investigate the use of ethanol as an alternative to freezing for the preservation of steroid and indoleamine hormones in avian plasma. Known quantities of the steroids 5alpha-dihydrotestosterone (DHT), testosterone, 17beta-estradiol, corticosterone, and the indoleamine melatonin were added to a stripped pool of chicken plasma. Samples were either immediately frozen at -40 degrees C, or treated with pure ethanol. Ethanol-treated samples were either immediately frozen, or-to simulate storage conditions at various field locations-left sitting at room temperature for one to two months, or incubated at 36 degrees C for one month before all treatment groups were frozen at -40 degrees C. All samples were then analyzed by radioimmunoassay. For DHT and estradiol there were no differences among treatment groups suggesting that ethanol-treatment is as effective as immediate freezing in preserving plasma steroid concentrations. For testosterone, corticosterone and melatonin ethanol-treated samples differed significantly from immediately frozen samples suggesting that caution is needed when comparing absolute concentrations of hormones between samples preserved in different ways. However, differences among ethanol-treated samples in general were small, demonstrating the feasibility of this preservation method in the field at remote locations.

Monolayer tungsten sulfide (WS 2 ), a desirable transition metal chalcogenide semiconductor material for the next generation of promising electronics and optoelectronics applications, has attracted great attention. However, the lack of understanding of the underlying growth mechanism in the chemical vapor deposition process inhibits the precise dimension control of WS 2 and its practical applications. Herein, we discovered that H 2 played an important role in the growth of WS 2 when tungsten trioxide (WO 3 ) was used as W precursor. It was found that a prereduction of WO 3 prior to the WS 2 growth is necessary, and the time to introduce H 2 into the growth system is crucial. The intermediate product of volatile W 18 O 49 contributed to the formation of single-crystal WS 2 only when the H 2 was introduced after the growth temperature reached 850 °C. The Gibbs free energy of the involved reactions was examined, and an intermediate-driven growth mechanism was proposed. The photodetector fabricated from the monolayer WS 2 exhibited a fast response speed and stable performance. A better understanding of the growth mechanism of WS 2 and the photodetector application demonstrated in this work offer guidelines for the study of other 2D materials.

Monolayer tungsten sulfide (WS 2 ), a desirable transition metal chalcogenide semiconductor material for the next generation of promising electronics and optoelectronics applications, has attracted great attention. However, the lack of understanding of the underlying growth mechanism in the chemical vapor deposition process inhibits the precise dimension control of WS 2 and its practical applications. Herein, we discovered that H 2 played an important role in the growth of WS 2 when tungsten trioxide (WO 3 ) was used as W precursor. It was found that a prereduction of WO 3 prior to the WS 2 growth is necessary, and the time to introduce H 2 into the growth system is crucial. The intermediate product of volatile W 18 O 49 contributed to the formation of single-crystal WS 2 only when the H 2 was introduced after the growth temperature reached 850 °C. The Gibbs free energy of the involved reactions was examined, and an intermediate-driven growth mechanism was proposed. The photodetector fabricated from the monolayer WS 2 exhibited a fast response speed and stable performance. A better understanding of the growth mechanism of WS 2 and the photodetector application demonstrated in this work offer guidelines for the study of other 2D materials.

Most of the world’s mountain glaciers have been retreating for more than a century in response to climate change. Glacier retreat is evident on all continents, and the rate of retreat has accelerated during recent decades. Accurate, spatially explicit information on the position of glacier margins over time is useful for analyzing patterns of glacier retreat and measuring reductions in glacier surface area. This information is also essential for evaluating how mountain ecosystems are evolving due to climate warming and the attendant glacier retreat. Here, we present a non-comprehensive spatially explicit dataset showing multiple positions of glacier fronts since the Little Ice Age (LIA) maxima, including many data from the pre-satellite era. The dataset is based on multiple historical archival records including topographical maps; repeated photographs, paintings, and aerial or satellite images with a supplement of geochronology; and own field data. We provide ESRI shapefiles showing 728 past positions of 94 glacier fronts from all continents, except Antarctica, covering the period between the Little Ice Age maxima and the present. On average, the time series span the past 190 years. From 2 to 46 past positions per glacier are depicted (on average: 7.8).

Most of the world’s mountain glaciers have been retreating for more than a century in response to climate change. Glacier retreat is evident on all continents, and the rate of retreat has accelerated during recent decades. Accurate, spatially explicit information on the position of glacier margins over time is useful for analyzing patterns of glacier retreat and measuring reductions in glacier surface area. This information is also essential for evaluating how mountain ecosystems are evolving due to climate warming and the attendant glacier retreat. Here, we present a non-comprehensive spatially explicit dataset showing multiple positions of glacier fronts since the Little Ice Age (LIA) maxima, including many data from the pre-satellite era. The dataset is based on multiple historical archival records including topographical maps; repeated photographs, paintings, and aerial or satellite images with a supplement of geochronology; and own field data. We provide ESRI shapefiles showing 728 past positions of 94 glacier fronts from all continents, except Antarctica, covering the period between the Little Ice Age maxima and the present. On average, the time series span the past 190 years. From 2 to 46 past positions per glacier are depicted (on average: 7.8).