Greenland Ice Sheet and rising sea level in a worst-case climate change scenario

Models that simulate sheet flow in the Greenland Ice Sheet balance forces at gridpoints in the map plan, which allows only a slow response to changes in climate forcing. A holistic approach to modeling allows a rapid response that takes place in ice streams. Holistic modeling results are presented that lengthen and lower the profiles of Greenland ice streams. This occurs because surface meltwater from greenhouse" warming reaches the bed through crevasses, and thereby increases basal water pressure. Thinning is then controlled primarily by increased basal water pressure that lengthens ice streams. If thinning caused by this process is both rapid and simultaneous for the major Greenland ice streams, the resulting iceberg outbursts might trigger an episode of rapid climate change

PROFITABILITY OF VARIABLE RATE PHOSPHORUS IN A TWO CROP ROTATION

In the Midwest, the adoption of precision farming technologies began in the early 1990s. Research has produced profiles of early adopters, evaluated adoption trends and has identified factors that influence the adoption and profitability of precision farming. Importantly, this information is available to producers, who are interested in precision farming issues. In addition, the Midwest regional agricultural industry, strong promoters of precision farming technologies, has gained the confidence of farmers who now rely on them heavily for information on farming technologies. Precision farming in Arkansas, however, is still in its infancy. Adoption levels lag far behind those in the Midwest. Two reasons for this lag have been offered. First, some suggest that much of what is believed about the technologies in the state is based on hearsay or the results of small single farm case study analyses. Because these beliefs have not been rigorously substantiated with extensive empirical evidence it has not been possible to truly assess the status of adoption, to predict potential adoption trends, or to adequately advise farmers in a decision to include precision farming in their farm management plan. Second, others suggest that agricultural industry has not taken an active role in the promotion and sale of precision farming equipment and services. Without local availability, all the research in the world will not lead to adoption of technology in the state. The objective of this paper is to provide critical information to Arkansas agricultural producers, industry and extension with answers regarding 1) the current status of precision farming 2) the amount, source and effectiveness of precision farming promotion and 3) the potential future of precision farming in Arkansas. In the Spring of 1999, three groups, early adopters of precision farming technologies (EA), Cooperative Extension Service personnel (CES) and agricultural industry personnel (AI), were surveyed to ascertain the realities and perceptions of precision farming in Arkansas. The surveys included questions related to characteristics of early adopters, factors encouraging and hindering adoption, and the roles of CES and AI in the promotion of precision farming within Arkansas. The survey response rate was over 60 percent. To build profiles of Arkansas EA to compare responses regarding sources of precision farming information across all three groups three statistical tools were used to test hypotheses regarding factors which influence adoption. The surveys revealed that Arkansas EA are young, educated, computer using, experienced farmers controlling relatively large farms predominantly devoted to rice and soybean. These farmers currently employ yield and soil mapping, as well as VRT and GIS technologies in their operations. While many reasons (such as decreased costs, improved yields, and improved management capabilities) have been cited as factors that can encourage adoption, there are still any number of reasons why many Arkansas farmers have not yet adopted these technologies, including, technical difficulties, expense and unproven profitability. In addition, AI representatives see themselves as promoters of precision farming technologies in Arkansas while EA have cited instances of a lack of available equipment and also stated that they turn to CES rather than AI for farming information because they believe this is an unbiased source of information. The authors conclude that both reasons offered for the lag in adoption are likely and hope that these insights provide both the CES and AI representatives with information to help them focus their research and outreach activities so that more Arkansas producers can make informed decisions about precision farming.Crop Production/Industries,

Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep

A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27 families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since 1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. Atotal of 155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging between 0% and 48% (P<0.01). Significantly different infection frequencies with T. gondii were also observed for different families and ranged between 0% and 100% (P<0.01). Although the actual cause of each abortion was not verified, a highly significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection in the same families (P<0.01). The data presented here raise further questions regarding the significance of congenital transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods in the future. Key words: Toxoplasma gondii, ovine, toxoplasmosis, congenital, transmission, pedigree, sheep

High levels of congenital transmission of toxoplasma gondii in longitudinal and cross-sectional studies on sheep farms provides evidence of vertical transmission in ovine hosts

Recent research suggests that vertical transmission may play an important role in sustaining Toxoplasma gondii infection in some species. We report here that congenital transmission occurs at consistently high levels in pedigree Charollais and outbred sheep flocks sampled over a 3-year period. Overall rates of transmission per pregnancy determined by PCR based diagnosis, were consistent over time in a commercial sheep flock (69%) and in sympatric (60%) and allopatric (41%) populations of Charollais sheep. The result of this was that 53·7% of lambs were acquiring an infection prior to birth: 46·4% of live lambs and 90·0% of dead lambs (in agreement with the association made between T. gondii and abortion). No significant differences were observed between lamb sexes. Although we cannot distinguish between congenital transmission occurring due to primary infection at pregnancy or reactivation of chronic infection during pregnancy, our observations of consistently high levels of congenital transmission over successive lambings favour the latter

What really makes students like a web site? What are the implications for designing web-based language learning sites?

Faced with reduced numbers choosing to study foreign languages (as in England and Wales), strategies to create and maintain student interest need to be explored. One such strategy is to create âtasterâ courses in languages, for potential university applicants. The findings presented arise from exploratory research, undertaken to inform the design of a selection of web-based taster courses for less widely taught languages. 687 school students, aged 14-18, were asked to identify a web site that they liked and to state their main reason for liking it. They were invited to include recreational sites and told that their answers could help with web design for the taster courses. To explore the reasons, two focus groups were conducted and student feedback on the developing taster course site was collected. Students nominated search engines and academic sites, sites dedicated to hobbies, enthusiasms, youth culture and shopping. They liked them for their visual attributes, usability, interactivity, support for schoolwork and for their cultural and heritage associations, as well as their content and functionality. They emerged as sensitive readers of web content, visually aware and with clear views on how text should be presented. These findings informed design of the taster course site. They are broadly in line with existing design guidelines but add to our knowledge about school studentsâ use of the web and about designing web-based learning materials. They may also be relevant to web design at other levels, for example for undergraduates

The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations

Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4·4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18·9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues

Science, Technology, Engineering, and Mathematics Student Persistence at a HBCU Community College

The problem addressed in this basic qualitative study was the persistence of science, technology, engineering, and mathematics (STEM) students at a historically Black community college (HBCC) in the southern United States. This problem is important because understanding the key successes and challenges STEM students face may enable faculty and administrators to support low-persisting students through degree completion. The purpose of this study was to explore the perceptions of STEM students at a HBCC regarding their persistence toward degree completion. Astin’s theory of involvement and Reasons and Terenzini’s synthesis of persistence were used as the conceptual framework for this study. The research questions were designed to develop an understanding of what students perceived as the keys to their success and the challenges that influenced their persistence. Eight, third-semester STEM students enrolled during the fall of 2021 and spring of 2022 volunteered to participate in the study. Data were collected using audio recorded, semistructured interviews and were analyzed thematically applying manual coding strategies to develop emergent themes. Participants perceived an engaging and supportive environment, specific course and content alignment, being academically determined, having adequate resources, and culture and opportunity as keys to their success towards degree attainment. The implications for positive social change include the potential for increased empowerment of HBCC students and how they will be represented in STEM fields after graduation, with added ability to promote social awareness and contribute to their communities

Science, Technology, Engineering, and Mathematics Student Persistence at a HBCU Community College

The problem addressed in this basic qualitative study was the persistence of science, technology, engineering, and mathematics (STEM) students at a historically Black community college (HBCC) in the southern United States. This problem is important because understanding the key successes and challenges STEM students face may enable faculty and administrators to support low-persisting students through degree completion. The purpose of this study was to explore the perceptions of STEM students at a HBCC regarding their persistence toward degree completion. Astin’s theory of involvement and Reasons and Terenzini’s synthesis of persistence were used as the conceptual framework for this study. The research questions were designed to develop an understanding of what students perceived as the keys to their success and the challenges that influenced their persistence. Eight, third-semester STEM students enrolled during the fall of 2021 and spring of 2022 volunteered to participate in the study. Data were collected using audio recorded, semistructured interviews and were analyzed thematically applying manual coding strategies to develop emergent themes. Participants perceived an engaging and supportive environment, specific course and content alignment, being academically determined, having adequate resources, and culture and opportunity as keys to their success towards degree attainment. The implications for positive social change include the potential for increased empowerment of HBCC students and how they will be represented in STEM fields after graduation, with added ability to promote social awareness and contribute to their communities