Plague outbreaks in prairie-dog colonies associated with El Niño climatic events

The SGS-LTER research site was established in 1980 by researchers at Colorado State University as part of a network of long-term research sites within the US LTER Network, supported by the National Science Foundation. Scientists within the Natural Resource Ecology Lab, Department of Forest and Rangeland Stewardship, Department of Soil and Crop Sciences, and Biology Department at CSU, California State Fullerton, USDA Agricultural Research Service, University of Northern Colorado, and the University of Wyoming, among others, have contributed to our understanding of the structure and functions of the shortgrass steppe and other diverse ecosystems across the network while maintaining a common mission and sharing expertise, data and infrastructure.Plague (Yersinia pestis) was introduced to the western U.S. in the mid-20th century and is a significant threat to the persistence of black-tailed prairie dog (Cynomys ludovicianus) populations. The social, colonial habits of prairie dogs make them particularly susceptible to plague, and many flea species, including known carriers of plague, are associated with prairie dogs or their extensive burrow systems. Mortality during plague epizootics, or outbreaks, is nearly 100% (Cully and Williams 2001; J. Mammal. 82:894), resulting in the extinction of entire colonies. In northern Colorado, prairie dogs exist in metapopulations (Roach et al. 2001, J. Mammal. 82:946), in which colonies naturally isolated by topography, soils and vegetation are connected by dispersal. Dispersal of either infected prairie dogs or plague-resistant reservoir species is hypothesized to spread plague among colonies. Plague outbreaks therefore may disrupt the dynamics of prairie-dog metapopulations and affect regional persistence. In the context of a century of past eradication efforts that have drastically reduced prairie-dog numbers, and increasing agricultural and urban development, plague represents a relatively new and unique threat to prairie dogs and the species that are closely associated with them. Poster presented at the 6th SGS Symposium held on 1/10/03

Shortgrass Steppe LTER VI: examining ecosystem persistence and responses to global change, 2010-2014 proposal

Includes bibliographical references.The SGS-LTER research site was established in 1980 by researchers at Colorado State University as part of a network of long-term research sites within the US LTER Network, supported by the National Science Foundation. Scientists within the Natural Resource Ecology Lab, Department of Forest and Rangeland Stewardship, Department of Soil and Crop Sciences, and Biology Department at CSU, California State Fullerton, USDA Agricultural Research Service, University of Northern Colorado, and the University of Wyoming, among others, have contributed to our understanding of the structure and functions of the shortgrass steppe and other diverse ecosystems across the network while maintaining a common mission and sharing expertise, data and infrastructure.The Shortgrass Steppe Long-term Ecological Research (SGS-LTER) program focuses on how grassland ecosystems function and persist or change in the face of global change. Our conceptual framework asserts that climate, physiography, grazing, fire and landuse, operating over different spatial and temporal scales, are the dominant determinants of the structure, function, and persistence of the SGS. Using the shortgrass steppe (SGS) ecosystem of the North American Great Plains as a model, we seek to (1) identify the ecological attributes of grasslands that historically have resulted in their persistence and (2) understand these attributes in ways that will allow us to identify area of vulnerability and better forecast the future of grasslands in the face of global change. Given its geographic extent and history, the SGS encapsulates many of the features of a system driven by social-ecological interactions and the vulnerabilities of semiarid grasslands to global change. Our overarching question is: How will structure and function of the SGS respond to expected changes in climate, management, and land-use, and what will be the consequences

Mapping the potential yield of upland rice in Rondonia State.

The rice farming has a high socioeconomical importance for Brazilian population, and represents since the 1970?s, it is the main crop for agricultural borders opening. Aiming characterize the potential yield and to define the regions most favorable for growth upland rice, it was simulated the potential grain yield (PGY), potential evapotranspiration (ETP) and maximum transpiration (TRC) by anoriented process crop model. The simulations were based on cultivar BRSPrimavera, considering eight planting dates (Nov 1st, 10th, 20th, Dec 1st, 10th, 20th, 30th and Jan 9th), for 33 years of data weather (1980-2013), in seven locations at Rondônia state: Ariquemes, Cacoal, Guajara-Mirim, Ji-Paraná, Machadinho do Oeste, Porto Velho and Vilhena. The upland rice crop cycle ranged from 95 days from emergence (DAE) in Ariquemes to 99 DAE in Machadinho do Oeste. The PGY, ETP and TRC data set were spatialized for the region. Rondônia showed an average and standard deviation potential yield of 4393 and 477 kg ha-1. The average ETP was 584,8 mm/cycle, with variance of 1259.9 mm/cycle. Maximum and minimum values of ETP was found for Guajara-Mirim and Vilhena, planting dates of Nov 1st and Jan 9th, respectively. The spatialization of results demonstrated a trend of PGY reduction as the sowing date is delayed. The highest potential yield were found at Vilhena (4952.7 kg/ha) and Ariquemes (4461.4 kg/ha)

Irrigation efficiency simulation for common bean during dry season, in the municipality of Goiânia, Goiás.

Goiás State is considered the major common beans producer in the autumn/winter season. In this season, the common beans production is fully irrigated by Center Pivot. However, due to the water scarcity water, the water dispute among human consumption, power generation, industries and agriculture is increasing. Then, it is important to optimize their consumption in the agriculture. Crop models are excellent tools for that and were used in this study to simulate the irrigation efficiency during the winter season for two cultivars, Pérola and BRS Radiante. Five planting dates from April to August and five irrigation amounts (10, 15, 20, 25 and 30 mm) applied when the soil water content reaches 50% of field capacity (CC) were considered. For cultivar Pérola, longer cycle, the best irrigation efficiency was obtained at the end of planting season, in the month of August, for the fixed irrigation amounts of 20 and 25 mm respectively. In the other hand, for the short cycle cultivar, BRS Radiante, the best irrigation efficiency was obtained only at the begin of planting date season, April

An Early Neolithic enclosure at the site of Vlaho, Pelagonia

[EN] Recent study of Vlaho in Pelagonia confirms that it is the earliest known Neolithic settlement in North Macedonia. Multidisciplinary research of the architecture and material reveals a complex enclosure site dating to the seventh millennium BC, with dozens of ditches, daub buildings, white painted pottery and domesticated plants and animals

The Influence of Sylvatic Plague on North American Wildlife at the Landscape Level, with Special Emphasis on Black-footed Ferret and Prairie Dog Conservation

Prairie-dogs are distributed over a large part of the Great Plains and Rocky Mountain regions. Their colonies often number thousands of individuals, and their destruction of grasses and other forage plants makes them of considerable economic importance. Drastic measures are frequently necessary to prevent the destruction of crops of grain and hay. The Biological Survey is exterminating these rodents in national forests and in the public domain. The information in this report, in regards to the several species and their distribution, as indicated by maps, will aid materially in efforts, national or state, to control or exterminate them, said Henry W. Henshaw in 1915 (Hollister 1916)

Classic flea-borne transmission does not drive plague epizootics in prairie dogs

We lack a clear understanding of the enzootic maintenance of the bacterium (Yersinia pestis) that causes plague and the sporadic epizootics that occur in its natural rodent hosts. A key to elucidating these epidemiological dynamics is determining the dominant transmission routes of plague. Plague can be acquired from the bites of infectious fleas (which is generally considered to occur via a blocked flea vector), inhalation of infectious respiratory droplets, or contact with a short-term infectious reservoir. We present results from a plague modeling approach that includes transmission from all three sources of infection simultaneously and uses sensitivity analysis to determine their relative importance. Our model is completely parameterized by using data from the literature and our own field studies of plague in the black-tailed prairie dog (Cynomys ludovicianus). Results of the model are qualitatively and quantitatively consistent with independent data from our field sites. Although infectious fleas might be an important source of infection and transmission via blocked fleas is a dominant paradigm in the literature, our model clearly predicts that this form of transmission cannot drive epizootics in prairie dogs. Rather, a short-term reservoir is required for epizootic dynamics. Several short-term reservoirs have the potential to affect the prairie dog system. Our model predictions of the residence time of the shortterm reservoir suggest that other small mammals, infectious prairie dog carcasses, fleas that transmit plague without blockage of the digestive tract, or some combination of these three are the most likely of the candidate infectious reservoirs. disease modeling ͉ disease reservoir ͉ Yersinia pestis ͉ Cynomys ludovicianu

The Kaon-Photoproduction Of Nucleons In The Quark Model

In this paper, we develop a general framework to study the meson-photoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the Chew-Goldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, $\gamma p\to K^+ \Lambda$, $\gamma p\to K^+ \Sigma^0$, and $\gamma p\to K^0\Sigma^+$, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches.Comment: 25 pages, 9 postscript figures can be obtained from the author

Potential of the three-Terminal heterojunction bipolar transistor solar cell for space applications

Multi-Terminal multi-junction solar cells (MJSC) offer higher efficiency potential than series connected (two-Terminal) ones. In addition, for terrestrial applications, the efficiency of multi-Terminal solar cells is less sensitive to solar spectral variations than the two-Terminal series-connected one. In space, generally, cells are always illuminated with AM0 spectrum and no impact is expected from spectral variations. Still, in space, the multi-Terminal approach offers some advantages in comparison with the series-connected architecture approach derived from a higher end of life (EOL) efficiency. In this work we review the potential of multi-Terminal solar cells for achieving extended EOL efficiencies with emphasis in the potential of the three-Terminal heterojunction bipolar transistor solar cell, a novel multi-Terminal MJSC architecture with a simplified structure not requiring, for example, tunnel junctions