A Short Wavelength GigaHertz Clocked Fiber-Optic Quantum Key Distribution System

A quantum key distribution system has been developed, using standard telecommunications optical fiber, which is capable of operating at clock rates of greater than 1 GHz. The quantum key distribution system implements a polarization encoded version of the B92 protocol. The system employs vertical-cavity surface-emitting lasers with emission wavelengths of 850 nm as weak coherent light sources, and silicon single photon avalanche diodes as the single photon detectors. A distributed feedback laser of emission wavelength 1.3 micro-metres, and a linear gain germanium avalanche photodiode was used to optically synchronize individual photons over the standard telecommunications fiber. The quantum key distribution system exhibited a quantum bit error rate of 1.4%, and an estimated net bit rate greater than 100,000 bits-per-second for a 4.2 km transmission range. For a 10 km fiber range a quantum bit error rate of 2.1%, and estimated net bit rate of greater than 7,000 bits-per-second was achieved.Comment: Pre-press versio

Iowa Farm and Rural Life Poll: 2011 Summary Report

The Iowa Farm and Rural Life Poll is an annual survey that collects and disseminates information on issues of importance to rural communities across Iowa and the Midwest. Conducted every year since its establishment in 1982, the Farm Poll is the longest-running survey of its kind in the nation. Iowa State University Extension and Outreach, the Iowa Agriculture and Home Economics Experiment Station, the Iowa Department of Agriculture and Land Stewardship, and the Iowa Agricultural Statistics Service are all partners in the Farm Poll effort. The information gathered through the Farm Poll informs the development and improvement of research and extension programs and is used by local, state, and national leaders in their decision-making processes. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the Farm Poll.https://lib.dr.iastate.edu/extension_communities_pubs/1021/thumbnail.jp

Iowa Farm and Rural Life Poll: 2012 Summary Report

The Iowa Farm and Rural Life Poll is an annual survey of Iowa farm families that collects and disseminates information on issues of importance to rural communities across Iowa and the Midwest. Conducted every year since its establishment in 1982, this is the Farm Poll’s 30th year. It is the longest-running survey of its kind in the nation. Iowa State University Extension and Outreach (ISUEO), the Iowa Agriculture and Home Economics Experiment Station, the Iowa Department of Agriculture and Land Stewardship (IDALS), and the Iowa Agricultural Statistics Service are active partners in the Farm Poll. The information gathered through the Farm Poll is used to inform the development and improvement of research and extension programs and is used by local, state, and national leaders in their decision-making processes. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the Farm Poll.https://lib.dr.iastate.edu/extension_communities_pubs/1022/thumbnail.jp

The Role of Farm Families in Local Community Philanthropy

Historically rural community development was rooted in self-help and collaborative efforts. Often organized on informal bases, these social actions and behaviors fell into the general rubric of “being a good neighbor.” Lacking access to political capital and external resources, residents of many small communities discovered that if something was going to get done, they had to do it themselves. Cooperative community action such as building schools, churches, stringing early electrical lines, and other public goods were rooted in a common belief that neighbors helping each other was the only viable way to make community improvements. These shared values of helping each other were manifested in citizens investing in their own community for local development. One of the hallmarks of rural communities was doing it their own way and not accepting outside resources with strings attached.https://lib.dr.iastate.edu/extension_communities_pubs/1023/thumbnail.jp

Assessing and presenting summaries of evidence in Cochrane Reviews

Cochrane Reviews are intended to help providers, practitioners and patients make informed decisions about health care. The goal of the Cochrane Applicability and Recommendation Methods Group (ARMG) is to develop approaches, strategies and guidance that facilitate the uptake of information from Cochrane Reviews and their use by a wide audience with specific focus on developers of recommendations and on healthcare decision makers. This paper is part of a series highlighting developments in systematic review methodology in the 20 years since the establishment of The Cochrane Collaboration, and its aim is to present current work and highlight future developments in assessing and presenting summaries of evidence, with special focus on Summary of Findings (SoF) tables and Plain Language Summaries. A SoF table provides a concise and transparent summary of the key findings of a review in a tabular format. Several studies have shown that SoF tables improve accessibility and understanding of Cochrane Reviews. The ARMG and GRADE Working Group are working on further development of the SoF tables, for example by evaluating the degree of acceptable flexibility beyond standard presentation of SoF tables, developing SoF tables for diagnostic test accuracy reviews and interactive SoF tables (iSoF). The plain language summary (PLS) is the other main building block for dissemination of review results to end-users. The PLS aims to summarize the results of a review in such a way that health care consumers can readily understand them. Current efforts include the development of a standardized language to describe statistical results, based on effect size and quality of supporting evidence. Producing high quality PLS and SoF tables and making them compatible and linked would make it easier to produce dissemination products targeting different audiences (for example, providers, health policy makers, guideline developers). Current issues of debate include optimal presentation formats of SoF tables, the training required to produce SoF tables, and the extent to which the authors of Cochrane Reviews should provide explicit guidance to target audiences of patients, clinicians and policy-makers

The eastern boundary of the Gulf Stream recirculation

A meridionally aligned thermocline front near 60W in the subtropical North Atlantic is revealed by the 1992 Trident data set. The front separates saltier thermocline water to the east from less salty water to the west. The eastern water is subjected to excess evaporation of the subtropics, while the western water is fed by lower salinity Gulf Stream water, which derives water from the wet tropical Atlantic. It is suggested that the front marks the eastern edge of the Gulf Stream recirculation cell, hence refer to it as the recirculation front. The surface layer displays a fan-like T/S scatter above the 18°C Subtropical Mode Water, with the fresher surface water located west of the recirculation front, and a subsurface salinity maximum to the east. In the lower thermocline (8 to 12°C) there is a step-like salinity increase of about 0.04 toward the east as measured along isotherms, producing two modes in the T/S scatter. At the intermediate water level (approximately in the 4 to 8°C range) the extent of the low salinity Antarctic Intermediate Water and salty Mediterranean outflow water are also reflected in the position of the recirculation front. That the front marks the easternmost extent of the Gulf Stream recirculation is supported by the potential vorticity, which reveals a region of high homogeneous values within the recirculation cell. East of the front, the potential vorticity field is sloped along isopycnals indicating the meridional flow of the Sverdrup interior. Mapping of the recirculation front using archived data reveals that it extends deep into the subtropical convergence zone (STCZ), a region whose fronts have all been previously attributed to Ekman convergence

Iowa Farm and Rural Life Poll: 2007 Summary Report

Iowa farm families have both hopes and concerns associated with changes unfolding across the state, especially those related to the rapid development of the “bioeconomy.” The increasing focus on renewable fuels, especially ethanol and biodiesel, brings both great expectations for grain prices and economic growth as well as worries about impacts on the environment and the structure of agriculture. The 2007 Iowa Farm and Rural Life Poll asked questions about these issues and related topics such as land use and future farm plans. The poll was created in 1982 by Iowa State University Extension, the Iowa Agriculture and Home Economics Experiment Station, and the Iowa Department of Agriculture and Land Stewardship. It partners Extension and research programs with the needs of farm families. Data collected on issues of importance to the farming community provide input to local, state, and national leaders in their decision making process. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the poll.https://lib.dr.iastate.edu/extension_communities_pubs/1015/thumbnail.jp

Iowa Farm and Rural Life Poll: 2008 Summary Report

Established in 1982, the Iowa Farm and Rural Life Poll is conducted through a partnership between Iowa State University Extension, the Iowa Agriculture and Home Economics Experiment Station, and the Iowa Department of Agriculture and Land Stewardship. Generally known as “The Farm Poll,” this annual survey effort collects and disseminates information on issues of importance to rural communities across Iowa and the Midwest. The Farm Poll serves to inform the development and improvement of extension and research programs and is used by local, state, and national leaders in their decisionmaking processes. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the poll.https://lib.dr.iastate.edu/extension_communities_pubs/1017/thumbnail.jp

Bose-Einstein transition temperature in a dilute repulsive gas

We discuss certain specific features of the calculation of the critical temperature of a dilute repulsive Bose gas. Interactions modify the critical temperature in two different ways. First, for gases in traps, temperature shifts are introduced by a change of the density profile, arising itself from a modification of the equation of state of the gas (reduced compressibility); these shifts can be calculated simply within mean field theory. Second, even in the absence of a trapping potential (homogeneous gas in a box), temperature shifts are introduced by the interactions; they arise from the correlations introduced in the gas, and thus lie inherently beyond mean field theory - in fact, their evaluation requires more elaborate, non-perturbative, calculations. One illustration of this non-perturbative character is provided by the solution of self-consistent equations, which relate together non-linearly the various energy shifts of the single particle levels k. These equations predict that repulsive interactions shift the critical temperature (at constant density) by an amount which is positive, and simply proportional to the scattering length a; nevertheless, the numerical coefficient is difficult to compute. Physically, the increase of the temperature can be interpreted in terms of the reduced density fluctuations introduced by the repulsive interactions, which facilitate the propagation of large exchange cycles across the sample.Comment: two minor corrections, two refs adde