747 research outputs found
Laboratory Thermal Expansion Measuring Techniques Applied To Bituminous Concrete : Informational Report
Consumptive water usage of evaporative pads
Dairy Research, 2006 is known as Dairy Day, 2006Consumptive water usage by evaporative pads was measured during 7 days of a 3-week period at a Kansas (KS) dairy and a 2-day pe-riod at a North Dakota (ND) dairy. Water me-ters were installed between the water hydrants, and evaporative pads at each dairy, and were monitored. Data were recorded every 30 min-utes during 5 hr at the KS site and every 15 minutes during 1 to 2.5 hr at the ND site. Ra-tio of pad area to cow equaled 4.8 and 4.5 ft2 per cow at the KS and ND sites, respectively. Airflow rates through the pads were 1.2, 2.1, and 3.2 mph at the ND dairy and 3.3 mph at the KS dairy. During the study period in KS, the temperature humidity index ranged from 78 to 86 and water usage varied from 0.7 to 4.7 gallon per minute. Average pad efficiency equaled 62%. Water usage averaged 0.3 gal-lons per hr per ft2 of pad when airflow rate was 3.3 to 3.6 mph. At the ND dairy, the wa-ter usage averaged 0.1, 0.3, and 0.38 gallon per hr per ft2 of pad for the low, medium, and high airflow rates, respectively. The tempera-ture humidity index equaled 65, 72.5, and 71 for the low, medium, and high airflow study periods. Pad efficiency averaged 93, 86, and 81% from the low to high airflow rates. Simi-lar to pad efficiencies at the KS site, efficiency increased as the outdoor air temperature de-creased.
(Key Words: Coolin
Dynamics of mycorrhizae during development of riparian forests along an unregulated river
In this study, we explore two mycorrhizal groups during development of riparian soils along a freely‐flowing river. We provide the first documentation of a shift in abundance between arbuscular mycorrhizae and ectomycorrhizae during floodplain succession. We used a chronosequence spanning 0–70 yr along a river in northwestern Montana, USA, to test the hypothesis that abundance of arbuscular mycorrhizal fungi (AMF) is greatest in early stages of soil development, and abundance of ectomycorrhizal fungi (ECMF) is greatest later in floodplain succession. We also measured the AMF‐mediated process of formation of soil aggregates during site development. AMF colonization of the dominant tree (black cottonwood, Populus trichocarpa) remained low (<5%), while AMF colonization of understory species was high (45–90%), across the chronosequence. Mycorrhizal inoculum potential (MIP) and hyphal length of AMF in soil peaked within the first 13 yr of succession and then declined. No single variable significantly correlated with AMF abundance, but AMF tended to decline as litter and soil organic matter increased. Density of ectomycorrhizal root tips in soil increased linearly throughout the chronosequence, and ectomycorrhizal colonization of cottonwood roots increased rapidly in early stages of succession. These patterns suggest that ECMF are not limited by dispersal, but rather influenced by abundance of host plants. Formation of water stable aggregates increased rapidly during the first third of the chronosequence, which was the period of greatest AMF abundance in the soil. The peak in AMF infectivity and hyphal length during early succession suggests that regular flooding and establishment of new sites promotes AMF abundance in this ecosystem. Regulation of rivers that eliminates creation of new sites may reduce contributions of AMF to riparian areas
Climate, Hydrologic Disturbance, and Succession: Drivers of Floodplain Pattern
Floodplains are among the world\u27s most threatened ecosystems due to the pervasiveness of dams, levee systems, and other modi. cations to rivers. Few unaltered floodplains remain where we may examine their dynamics over decadal time scales. Our study provides a detailed examination of landscape change over a 60-year period ( 1945 - 2004) on the Nyack floodplain of the Middle Fork of the Flathead River, a free-flowing, gravel-bed river in northwest Montana, USA. We used historical aerial photographs and airborne and satellite imagery to delineate habitats ( i.e., mature forest, regenerative forest, water, cobble) within the. oodplain. We related changes in the distribution and size of these habitats to hydrologic disturbance and regional climate. Results show a relationship between changes in. oodplain habitats and annual flood magnitude, as well as between hydrology and the cooling and warming phases of the Pacific Decadal Oscillation (PDO). Large magnitude floods and greater frequency of moderate floods were associated with the cooling phases of the PDO, resulting in a floodplain environment dominated by extensive restructuring and regeneration of floodplain habitats. Conversely, warming phases of the PDO corresponded with decreases in magnitude, duration, and frequency of critical flows, creating a floodplain environment dominated by late successional vegetation and low levels of physical restructuring. Over the 60-year time series, habitat change was widespread throughout the floodplain, though the relative abundances of the habitats did not change greatly. We conclude that the long- and short-term interactions of climate, floods, and plant succession produce a shifting habitat mosaic that is a fundamental attribute of natural. oodplain ecosystems
The role of the global cryosphere in the fate of organic contaminants
The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate. Given the complexity of contaminant interactions with the cryosphere and limitations on resources and research capacity, interdisciplinary research and extended collaborations are essential to close identified knowledge gaps and to improve our understanding of contaminant fate under a changing climate
RGS4 RNA secondary structure mediates Staufen2 RNP assembly in Neurons
RNA‐binding proteins (RBPs) act as posttranscriptional regulators controlling the fate of target mRNAs. Unraveling how RNAs are recognized by RBPs and in turn are assembled into neuronal RNA granules is therefore key to understanding the underlying mechanism. While RNA sequence elements have been extensively characterized, the functional impact of RNA secondary structures is only recently being explored. Here, we show that Staufen2 binds complex, long‐ranged RNA hairpins in the 3′‐untranslated region (UTR) of its targets. These structures are involved in the assembly of Staufen2 into RNA granules. Furthermore, we provide direct evidence that a defined Rgs4 RNA duplex regulates Staufen2‐dependent RNA localization to distal dendrites. Importantly, disrupting the RNA hairpin impairs the observed effects. Finally, we show that these secondary structures differently affect protein expression in neurons. In conclusion, our data reveal the importance of RNA secondary structure in regulating RNA granule assembly, localization and even-tually translation. It is therefore tempting to speculate that secondary structures represent an important code for cells to control the intracellular fate of their mRNAs
Temporospatial shifts in Sandhill Crane staging in the Central Platte River Valley in response to climatic variation and habitat change
Over 80% of the Mid-Continent Sandhill Crane (Antigone canadensis) Population (MCP), estimated at over 660,000 individuals, stops in the Central Platte River Valley (CPRV) during spring migration from mid-February through mid-April. Research suggests that the MCP may be shifting its distribution spatially and temporally within the CPRV. From 2002 to 2017, we conducted weekly aerial surveys of Sandhill Cranes staging in the CPRV to examine temporal and spatial trends in their abundance and distribution. Then, we used winter temperature and drought severity measures from key wintering and early migratory stopover locations to assess the impacts of weather patterns on annual migration chronology in the CPRV. We also evaluated channel width and land cover characteristics using aerial imagery from 1938, 1998, and 2016 to assess the relationship between habitat change and the spatial distribution of the MCP in the CPRV. We used generalized linear models, cumulative link models, and Akaike’s information criterion corrected for small sample sizes (AICc) to compare temporal and spatial models. Temperatures and drought conditions at wintering and migration locations that are heavily used by Greater Sandhill Cranes (A. c. tabida) best predicted migration chronology of the MCP to the CPRV. The spatial distribution of roosting Sandhill Cranes from 2015 to 2017 was best predicted by the proportion of width reduction in the main channel since 1938 (rather than its width in 2016) and the proportion of land cover as prairie-meadow habitat within 800 m of the Platte River. Our data suggest that Sandhill Cranes advanced their migration by an average of just over 1 day per year from 2002 to 2017, and that they continued to shift eastward, concentrating at eastern reaches of the CPRV. Climate change, land use change, and habitat loss have all likely contributed to Sandhill Cranes coming earlier and staying longer in fewer reaches of the CPRV, increasing their site use intensity. These historically unprecedented densities may present a disease risk to Sandhill Cranes and other waterbirds, including Whooping Cranes (Grus americana). Our models suggest that conservation actions may be maintaining Sandhill Crane densities in areas that would otherwise be declining in use. We suggest that management actions intended to mitigate trends in the distribution of Sandhill Cranes, including wet meadow restoration, may similarly benefit prairie- and braided river–endemic species of concern.
Más del 80% de la población de grullas canadienses (Antigone canadensis), de la zona central del continente (MCP por sus siglas en inglés), estimada en más de 660,000, descansa en el valle central del Río Platte (CPRV por sus siglas en inglés) durante su migración de primavera, desde mediados de febrero hasta mediados de abril. Diversos estudios indican que su distribución espacial y temporal podría estar cambiando dentro del CPRV. Desde el año 2002 hasta el 2017 realizamos sondeos aéreos semanales de grullas canadienses en el CPRV para estudiar las tendencias temporales y espaciales relacionadas a su abundancia y distribución. Usamos mediciones de temperatura durante el invierno y de la severidad de la sequía de lugares claves de invernada y de sitios de descanso durante su migración temprana para evaluar el impacto de los patrones climáticos en la cronología migratoria anual del CPRV. También analizamos la amplitud del canal y las características de la cubierta terrestre usando imágenes aéreas de 1938, 1998 y 2016 con el fin de evaluar la relación entre el cambio de hábitat y la distribución espacial de la MCP en el CPRV. Utilizamos modelos lineales generalizados, modelos de enlace acumulativo y el criterio de información de Akaike adecuados a muestras pequeñas (AICc), para comparar modelos temporales y espaciales. Las condiciones climáticas y de sequía en los sitios de invernada y migración más usados por la grulla canadiense mayor (A. c. tabida) predijeron mejor la cronología migratoria de la MCP en el CPRV. La reducción de la amplitud del canal principal desde 1938, junto con el porcentaje de cubierta terrestre como hábitat de pradera dentro de los 800 m del río Platte, fue el mejor predictor de la distribución espacial de la grulla canadiense desde el año 2015 hasta el 2017. Nuestros estudios indican que las grullas canadienses adelantaron su migración en un promedio poco más de un día por año entre el 2002 y el 2017 y que continuaron desplazándose hacia el este, concentrándose en los extremos orientales del CPRV. El cambio climático, el cambio de uso del suelo y la pérdida del hábitat probablemente contribuyeron a la migración temprana de esta especie y a su permanencia más prolongada en algunos sectores del CPRV, aumentando la intensidad del uso del sitio. Estas densidades sin precedentes podrían presentar un riesgo de enfermedad para la grulla canadiense y otras aves acuáticas, incluidas las grullas trompeteras (Grus americana). Nuestros modelos indican que las medidas actuales de conservación podrían ser la causa de preservación de la densidad poblacional de la grulla canadiense en áreas en las que, de otra forma, su presencia estaría disminuyendo. Sugerimos que las medidas de control destinadas a mitigar la tendencia de distribución de la grulla canadiense, incluyendo la restauración de los prados húmedos, pueden beneficiar de igual manera a las especies endémicas, praderas y ríos trenzados de nuestro interés
Animation by Computer. a Tool for Understanding the Dynamical Behaviour of Ancient Machines
The datasets in this article are associated with the research article \u27Assessing biological and environmental effects of a total solar eclipse with passive multimodal technologies\u27 (Brinley Buckley et al., 2018). We documented biotic and abiotic changed during a total solar eclipse on 21 August 2017, in south-central Nebraska, USA, with a multimodel suite of tools, including time-lapse camera systems, data loggers, and sound recording devices. Time-lapse images were used to approximate changes in light, data loggers were used to record temperature and humidity, and sound recordings were used to calculate acoustic indices characterizing variation in the soundscape, as well as to manually identify and estimate avian vocalization activity
Molecular and genetic analysis of iron uptake proteins in the Brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius. Front
Market analysis for cultured proteins in low- and lower-middle income countries.
The global burden of malnutrition is unacceptably high.10 Worldwide, an estimated 22% of children under the age of five were stunted and 8% were wasted in 2018.11 Low-quality diets lacking in essential vitamins, minerals, proteins, and other nutrients are a key contributor to this burden.12 Animal-source foods—such as meat, poultry, fish, eggs, and dairy—are important components of a diverse diet and provide high-quality proteins and other essential nutrients that promote optimal growth and development.13,14,15,16,17As populations and incomes grow, the global demand for animal-source foods is projected to increase substantially, particularly in many low- and lower-middle income countries (LMICs).18,19 However, cost is currently a significant barrier to animal-source food consumption. In addition, meeting this growing demand for animal-source foods will require rapid increases in livestock production, which has significant environmental impacts, requiring considerable land, water, chemical, and energy inputs.10,17,18 Global food production is responsible for roughly one-quarter of all greenhouse gas emissions, most of which (up to 80%) are related to livestock.20,21 Livestock production is also a contributor to water pollution, deforestation, land degradation, overfishing, and antimicrobial resistance.20,22,23 Given these challenges, this report aims to assess the market for potentially more sustainable alternative proteins and their potential for use in LMIC settings. The report focuses on proteins derived from fermentation-based cellular agriculture, called cultured proteins, given their potential near-term time to market and their potential impact in LMIC populations. Most cultured protein manufacturers are developing proteins that are present in animal-source milk and eggs
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