Integrated intensity measurements in crystal structure analysis

Some fundamental aspects of the photographic process are described and the relationship between exposure time and density is discussed. A review of some of the techniques employed in the measurement of the intensities of X-ray reflections is given. Among the techniques reviewed are; the visual method of estimation, the application of photometric techniques In the measurement of peak and integrated intensities and the application of counters in the direct monitoring of the X-ray beam. The Joyce-Loebl integrating microdensitometer is described, its function and operation discussed. The Instrument has a linear response up to about 1.5 D and the linear response of ILFORD INDUSTRIAL G, a double coated X-ray film, extends to 0.7 D. Ideally the I.D.V. corresponding to the limiting density of 0.7 D should be about 250 units, corresponding to a circular spot of about 0.3 mm diameter. Such a spot would be accommodated with X and Y sweeps of 3. Very large spots should be avoided because of the loss of recording sensitivity at high X sweep values and very small spots should be avoided because of their very narrow I.D.V. range. A limitation on the use of the instrument is caused by the disparity in linear response between the instrument itself and the double coated film normally used. It is recommended that double coated film be replaced with single coated film for the purposes of the intensity record. The advantage of such a move would be a wider and more accurately measured recording range. The intensity record used in the crystal structure analysis of 2-thioamidopyridine has been obtained by means of the Joyce-Loebl integrating microdensitometer. The bond lengths and angles obtained from the analysis show good agreement with similar bond lengths and angles in related molecules. It is concluded that the integrating microdensitometer provides a reliable intensity measurement and suggestions are made which should enable maximum accuracy to be obtained from the instrument in the future

Demographic and Management Factors Affecting the Adoption and Perceived Yield Benefit of Winter Cover Crops in the Southeast

The inclusion of cover crops in cropping systems brings direct and indirect costs and benefits. Farmers will adopt and utilize cover crops as long as the perceived benefit of using them is positive. This paper examines the demographic and management factors affecting the adoption and perceived benefit (in terms of improved crop yield) of using winter annual cover crops. A double selectivity model of cover crop adoption and perceived yield gain was estimated using survey data of Alabama farmers examining cover crop use and management. Results may help in understanding factors shaping farmers’ perceptions, adoption, and retention of cover crops.adoption, conservation, cover crops, double selectivity model, perceived yield gain, tobit model, Environmental Economics and Policy, Farm Management, Q12, Q15, Q55,

ADOPTION OF BEST MANAGEMENT PRACTICES IN STOCKER CATTLE PRODUCTION

This study identifies current production and management practices of Oklahoma stocker cattle producers and analyzes factors affecting the adoption of best management practices (BMPs) using chi-square analysis. Results reveal that factors influencing the adoption of BMPs are operation size, dependency upon income from the operation, and specialization in stocker production.cattle, stockers, management, production, Livestock Production/Industries,

Demographic Influences on Nonadoption of Calf Management and Marketing Practices for Cow-Calf Operations

Though research indicates that many calf management and marketing practices are available to add value for the cow-calf producer, a high percentage of producers are still nonadopters of such practices. Little information identifies nonadopters in the beef cattle industry, limiting efforts to provide educational support. This study uses a binomial logit model and primary survey data to examine the demographic influence on producers’ nonadoption of commonly recommended value-added management and marketing practices specific to feeder calves in the cow-calf segment

Rectangular Hierarchical Cartograms for Socio-Economic Data

We present rectangular hierarchical cartograms for mapping socio-economic data. These density-normalising cartograms size spatial units by population, increasing the ease with which data for densely populated areas can be visually resolved compared to more conventional cartographic projections. Their hierarchical nature enables the study of spatial granularity in spatial hierarchies, hierarchical categorical data and multivariate data through false hierarchies. They are space-filling representations that make efficient use of space and their rectangular nature (which aims to be as square as possible) improves the ability to compare the sizes (therefore population) of geographical units. We demonstrate these cartograms by mapping the Office for National Statistics Output Area Classification (OAC) by unit postcode (1.52 million in Great Britain) through the postcode hierarchy, using these to explore spatial variation. We provide rich and detailed spatial summaries of socio-economic characteristics of population as types of treemap, exploring the effects of reconfiguring them to study spatial and non-spatial aspects of the OAC classification

Emulating IPCC AR4 atmosphere-ocean and carbon cycle models for projecting global-mean, hemispheric and land/ocean temperatures: MAGICC 6.0

International audienceCurrent scientific knowledge on the future response of the climate system to human-induced perturbations is comprehensively captured by various model intercomparison efforts. In the preparation of the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), intercomparisons were organized for atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models, named "CMIP3" and "C4MIP", respectively. Despite their tremendous value for the scientific community and policy makers alike, there are some difficulties in interpreting the results. For example, key radiative forcings have not been considered or standardized in the majority of AOGCMs integrations and carbon cycle runs. Furthermore, the AOGCM analysis of plausible emission pathways was restricted to only three SRES scenarios. This study attempts to address these issues. We present an updated version of MAGICC, the simple carbon cycle-climate model used in past IPCC Assessment Reports with enhanced representation of time-varying climate sensitivities, carbon cycle feedbacks, aerosol forcings and ocean heat uptake characteristics. This new version of MAGICC (6.0) is successfully calibrated against the higher complexity AOGCM and carbon cycle models. Parameterizations of MAGICC 6.0 are provided. Previous MAGICC versions and emulations shown in IPCC AR4 (WG1, Fig. 10.26, page 803) yielded, in average, a 10% larger global-mean temperature increase over the 21st century compared to the AOGCMs. The reasons for this difference are discussed. The emulations presented here using MAGICC 6.0 match the mean AOGCM responses to within 2.2% for the SRES scenarios. This enhanced emulation skill is due to: the comparison on a "like-with-like" basis using AOGCM-specific subsets of forcings, a new calibration procedure, as well as the fact that the updated simple climate model can now successfully emulate some of the climate-state dependent effective climate sensitivities of AOGCMs. The mean diagnosed effective climate sensitivities of the AOGCMs is 2.88°C, about 0.33°C cooler than the reported slab ocean climate sensitivities. Finally, we examine the combined climate system and carbon cycle emulations for the complete range of IPCC SRES emission scenarios and some lower mitigation pathways

Demographic Factors Affecting the Adoption of Multiple Value-Added Practices by Oklahoma Cow-Calf Producers

The utilization of marketing programs to enhance feeder calf value has been met with modest success in Oklahoma. Value-added programs are continually promoted as avenues for improving cow-calf profitability, but producer adoption of value-added practices lags in spite of research showing the value of these practices. Identifying producer characteristics that increase their likelihood to adopt value-added practices is critical to developing successful outreach efforts. Results from a survey of Oklahoma producers on value-added practice adoption indicate that multiple demographic variables influence a producer’s likelihood of practice adoption. For Extension specialists, results can help in targeting likely adopters and developing methods to overcome barriers to adoption by producers less likely to adopt.Beef producers, value-added practices, practice adoption, negative binomial regression, Poisson regression, Farm Management, Livestock Production/Industries, Q12, Q16,

Determinants of Feedlot Cattle Death Loss Rates

Death loss in feedlot cattle can have significant impacts on feedlot profitability. Not only does death loss result in foregone revenue, but the operation still incurs the costs to date associated with those animals. This study uses pen-level feedlot data from a private feed-lot in the Southern Great Plains. Both company- owned and customer retained ownership cattle are included in the data set. A Tobit model is used to analyze pen characteristics’ influence on death loss in feedlot cattle, including cattle characteristics, source characteristics, management characteristics, and treatment incidence. Results imply that several pen characteristics impact death loss and that cattle source, in terms of both cattle source geographic location and market source type, has a significant influence on death loss rate

Sexual selection in mushroom-forming basidiomycetes

We expect that sexual selection may play an important role in the evolution of mushroom-forming basidiomycete fungi. Although these fungi do not have separate sexes, they do play female and male roles: the acceptance and the donation of a nucleus, respectively. The primary mycelium (monokaryon) of basidiomycete fungi, growing from a germinating sexual spore, is hermaphroditic, but it loses female function upon the acceptance of a second nucleus. The resulting dikaryon with two different nuclei in each cell retains a male potential as both nuclei can fertilize receptive mycelia. We tested the occurrence of sexual selection in the model species of mushroom-forming basidiomycetes, Schizophyllum commune, by pairing monokaryons with fully compatible dikaryons. In most pairings, we found a strong bias for one of the two nuclei although both were compatible with the monokaryon when paired alone. This shows that sexual selection can occur in mushroom-forming basidiomycetes. Since the winning nucleus of a dikaryon occasionally varied depending on the receiving monokaryon, we infer that sexual selection can operate through choosiness of the receiving individual (analogous to female choice). However, in other cases the same nucleus won, irrespective of the receiving monokaryon, suggesting that competition between the two nuclei of the donating mycelium (analogous to male–male competition) might also play a role