Optimal cooling strategies for magnetically trapped atomic Fermi-Bose mixtures

We discuss cooling efficiency for different-species Fermi-Bose mixtures in magnetic traps. A better heat capacity matching between the two atomic species is achieved by a proper choice of the Bose cooler and the magnetically trappable hyperfine states of the mixture. When a partial spatial overlap between the two species is also taken into account, the deepest Fermi degeneracy is obtained for an optimal value of the trapping frequency ratio. This can be achieved by assisting the magnetic trap with a deconfining light beam, as shown in the case of fermionic 6Li mixed with 23Na, 87Rb, and 133Cs, with optimal conditions found for the not yet explored 6Li-87Rb mixture.Comment: 5 pages, 3 figures, to appear in Physical Review

A new approach for predicting drought-related vegetation stress: Integrating satellite, climate, and biophysical data over the U.S. central plains

Droughts are normal climate episodes, yet they are among the most expensive natural disasters in the world. Knowledge about the timing, severity, and pattern of droughts on the landscape can be incorporated into effective planning and decisionmaking. In this study, we present a data mining approach to modeling vegetation stress due to drought and mapping its spatial extent during the growing season. Rule-based regression tree models were generated that identify relationships between satellite-derived vegetation conditions, climatic drought indices, and biophysical data, including land-cover type, available soil water capacity, percent of irrigated farm land, and ecological type. The data mining method builds numerical rule-based models that find relationships among the input variables. Because the models can be applied iteratively with input data from previous time periods, the method enables to provide predictions of vegetation conditions farther into the growing season based on earlier conditions. Visualizing the model outputs as mapped information (called VegPredict) provides a means to evaluate the model. We present prototype maps for the 2002 drought year for Nebraska and South Dakota and discuss potential uses for these maps

Thermodynamical Approaches to Efficient Sympathetic Cooling in Ultracold Fermi-Bose Atomic Mixtures

We discuss the cooling efficiency of ultracold Fermi-Bose mixtures in species-selective traps using a thermodynamical approach. The dynamics of evaporative cooling trajectories is analyzed in the specific case of bichromatic optical dipole traps also taking into account the effect of partial spatial overlap between the Fermi gas and the thermal component of the Bose gas. We show that large trapping frequency ratios between the Fermi and the Bose species allow for the achievement of a deeper Fermi degeneracy, consolidating in a thermodynamic setting earlier arguments based on more restrictive assumptions. In particular, we confirm that the minimum temperature of the mixture is obtained at the crossover between boson and fermion heat capacities, and that below such a temperature sympathetic cooling vanishes. When the effect of partial overlap is taken into account, optimal sympathetic cooling of the Fermi species may be achieved by properly tuning the relative trapping strength of the two species in a time-dependent fashion. Alternatively, the dimensionality of the trap in the final stage of cooling can be changed by increasing the confinement strength, which also results in a crossover of the heat capacities at deeper Fermi degeneracies. This technique may be extended to Fermi-Bose degenerate mixtures in optical lattices

Opening a networked learning dialogue on postdigital citizen science and humanities

Citizen science, or community science, is generally defined as the involvement of citizens in the collection and analysis of data in collaboration with professional scientists or ecologists. Citizen science initiatives have become more common as technological innovations have increased ways that individuals can participate, enabled larger scale projects and more volunteers to be engaged. Citizen humanities could be said to be a form of citizen science where investigation concerns human values and embedded, diverse, and culturally sensitive knowledge. The development of digital technologies has led to both the field of digital humanities and to new ways to involve citizens in the activities of cultural heritage institutions and academic research. These broad understandings of citizen science and citizen humanities are drawn from disciplinary distinctions concerning how we treat ‘the sciences’ or ‘the humanities’. This is primarily an English language distinction which is much less clear-cut in other languages and cultures, including the ways in which metaphors are adopted as explanatory tools but also carry tacit beliefs and assumptions. In postdigital society it is increasingly hard to separate people’s lives and diverse positionalities from scientific, technological, cultural, linguistic, and political economic changes as these converge to affect communities and individuals. Networked learning is a field that has always shown an active interest in convergences, contribution, and community along with a desire to avoid determinism when examining relationships between learning, technology, and social change. In this paper we draw on this critical networked learning ‘tone’ to explore the activities of citizen science and citizen humanities as they appear to operate as separate fields of research within postdigital society. We argue that discussing the postdigital context surrounding these fields contributes valuable perspectives of knowledge socialism, peer production, collegiality, collaboration, and collective intelligence to help fill certain gaps to meet challenges of the future through community and citizen research. Cross-sector projects that bridge citizen, social, or natural sciences and citizen humanities in diverse locations also need to be community led. This empowers communities not only to acquire new technology enabled capabilities as appropriate to their needs, but also to participate as citizens and activists in the wider political discourse. Therefore, in opening a critically reflexive and relational networked learning dialogue we can locate and occupy important gaps as we grow our understanding of ‘postdigital citizen science’ and ‘postdigital citizen humanities’ as dialectically intertwined fields of cross-sector community research

An Analysis of the CAP Reform

The Treaty of Rome, which established the European Economic Community in 1957, defined the objectives of the Common Agricultural Policy (CAP). These objectives, contained in Article 39, follow: 1) Increase agricultural productivity by promoting technical progress and by ensuring rational development of agricultural production and optimum use of the production factors, particularly labor. 2) Ensure a fair standard of living for the agricultural community, in particular by increasing the individual earning of the persons engaged in agriculture. 3) Stabilize markets. 4) Assure the availability of supplies. 5) Ensure that supplies reach consumers at reasonable prices. The objectives of the CAP have been met, mostly through price policies that traditionally have been tied to production. The result of these policies is that production of many agricultural commodities has increased beyond levels necessary to meet CAP objectives and excess supplies have accumulated, been exported with subsidies, or both, at great expense to the European Community

The Vegetation Drought Response Index (VegDRI): A New Integrated Approach for Monitoring Drought Stress in Vegetation

The development of new tools that provide timely, detailed-spatial-resolution drought information is essential for improving drought preparedness and response. This paper presents a new method for monitoring drought-induced vegetation stress called the Vegetation Drought Response Index (VegDRI). VegDRI integrates traditional climate-based drought indicators and satellite-derived vegetation index metrics with other biophysical information to produce a 1 km map of drought conditions that can be produced in near-real time. The initial VegDRI map results for a 2002 case study conducted across seven states in the north-central United States illustrates the utility of VegDRI for improved large-area drought monitoring

The Vegetation Outlook (VegOut): A New Method for Predicting Vegetation Seasonal Greenness

The vegetation outlook (VegOut) is a geospatial tool for predicting general vegetation condition patterns across large areas. VegOut predicts a standardized seasonal greenness (SSG) measure, which represents a general indicator of relative vegetation health. VegOut predicts SSG values at multiple time steps (two to six weeks into the future) based on the analysis of “historical patterns” (i.e., patterns at each 1 km grid cell and time of the year) of satellite, climate, and oceanic data over an 18-year period (1989 to 2006). The model underlying VegOut capitalizes on historical climate–vegetation interactions and ocean–climate teleconnections (such as El Niño and the Southern Oscillation, ENSO) expressed over the 18-year data record and also considers several environmental characteristics (e.g., land use/cover type and soils) that influence vegetation’s response to weather conditions to produce 1 km maps that depict future general vegetation conditions. VegOut provides regional level vegetation monitoring capabilities with local-scale information (e.g., county to sub-county level) that can complement more traditional remote sensing–based approaches that monitor “current” vegetation conditions. In this paper, the VegOut approach is discussed and a case study over the central United States for selected periods of the 2008 growing season is presented to demonstrate the potential of this new tool for assessing and predicting vegetation conditions

Implications of a GATT Agreement for World Commodity Markets, 1993-98: An Analysis of the Dunkel Text on Agriculture

The Food and Agricultural Policy Research Institute (FAPRI) received a request in mid-February to analyze the proposed changes to agriculture and agricultural trade made by Arthur Dunkel. These changes essentially fall into three areas. 1) Export Competition. Subsidies are subject to reduction in two ways. Expenditures are to be reduced by 36 percent and quantities exported with the benefit of subsidies are to be reduced by 24 percent from 1986-90 average levels. 2) Internal Support. Using a world reference price based on the 1986-88 average levels, internal supports as measured by an aggregate measure of support (AMS) are to be reduced by 20 percent from 1986 levels. Credit will be given for support reductions made since 1986. 3) Market Access. Import restrictions are to be converted to tariffs and reduced across the board by a simple average of 36 percent. Tariffs on individual commodities are to be reduced by at least 15 percent. Where import barriers are in place, either minimum access of 3 percent of domestic consumption in 1993, rising to 5 percent in 1999, or minimum access of 1986-88 average import levels is to be provided, whichever is greater

Assessing the Vegetation Condition Impacts of the 2011 Drought across the U.S. Southern Great Plains Using the Vegetation Drought Response Index (VegDRI)

The vegetation drought response index (VegDRI), which combines traditional climate- and satellite-based approaches for assessing vegetation conditions, offers new insights into assessing the impacts of drought from local to regional scales. In 2011, the U.S. southern Great Plains, which includes Texas, Oklahoma, and New Mexico, was plagued by moderate to extreme drought that was intensified by an extended period of recordbreaking heat. The 2011 drought presented an ideal case study to evaluate the performance of VegDRI in characterizing developing drought conditions. Assessment of the spatiotemporal drought patterns represented in the VegDRI maps showed that the severity and patterns of the drought across the region corresponded well to the record warm temperatures and much-below-normal precipitation reported by the National Climatic Data Center and the sectoral drought impacts documented by the Drought Impact Reporter (DIR). VegDRI values and maps also showed the evolution of the drought signal before the Las Conchas Fire (the largest fire in New Mexico’s history). Reports in the DIR indicated that the 2011 drought had major adverse impacts on most rangeland and pastures in Texas and Oklahoma, resulting in total direct losses of more than $12 billion associated with crop, livestock, and timber production. These severe impacts on vegetation were depicted by the VegDRI at subcounty, state, and regional levels. This study indicates that the VegDRI maps can be used with traditional drought indicators and other in situ measures to help producers and government officials with various management decisions, such as justifying disaster assistance, assessing fire risk, and identifying locations to move livestock for grazing