Integrating the inputs that shape pancreatic islet hormone release.

The pancreatic islet is a complex mini organ composed of a variety of endocrine cells and their support cells, which together tightly control blood glucose homeostasis. Changes in glucose concentration are commonly regarded as the chief signal controlling insulin-secreting beta cells, glucagon-secreting alpha cells and somatostatin-secreting delta cells. However, each of these cell types is highly responsive to a multitude of endocrine, paracrine, nutritional and neural inputs, which collectively shape the final endocrine output of the islet. Here, we review the principal inputs for each islet-cell type and the physiological circumstances in which these signals arise, through the prism of the insights generated by the transcriptomes of each of the major endocrine-cell types. A comprehensive integration of the factors that influence blood glucose homeostasis is essential to successfully improve therapeutic strategies for better diabetes management

The conundrum of conservation agriculture and livelihoods in Southern Africa

Low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in Southern Africa. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved livelihoods and environmental protection, better than the unsustainable traditional systems of slash and burn practices. In this paper, we present the results of a meta-analysis of over 40 academic publications to review conservation agriculture’s role in influencing desired livelihood outcomes in Southern Africa. We conclude that the effectiveness of conservation agriculture towards better livelihood outcomes in Southern Africa remains debatable, especially when supportive government policies are lacking

Constructing Consequences for Noncompliance: The Case of Academic Laboratories

We examine academic research laboratories as examples of intractable governance sites. These spaces often elude regulatory warnings and rules because of the professional status of faculty members, the opacity of scientific work to outsiders, and loose coupling of policy and practice in organizations. We describe one university’s efforts to create a system for managing laboratory health, safety, and environmental hazards, thereby constraining conventional faculty habit to ignore administrative and legal procedures. We demonstrate the specific struggles safety managers face in creating system responsiveness, that is, feedback to re-channel noncompliant laboratory practices. We show how faculty members are buffered from the consequences of their activities, thus impeding the goals of responsibility and accountability. We conclude by asking where such pockets of intractability reside in other organizations and whether the surrounding buffer, if there is one, may nonetheless paradoxically create an effective margin of safety.National Science Foundation (U.S.) (Grant 0216815)National Science Foundation (U.S.) (Grant 0518118)National Science Foundation (U.S.) (Grant 0535870

Explaining the Selection of Routines for Change during Organizational Search

We examine how organizations select some routines to be changed, but not others, during organizational search. Selection is a critical step that links an exogenous trigger for change, change in individual routines, and larger processes of organizational adaptation. Drawing on participant observation of an initiative to improve perioperative efficiency in seven Ontario hospitals, we find that organizational roles shape selection by influencing both politics and frames in organizational search. Roles shape politics by defining the role-specific goals of the people who have authority to change a routine. Organizations will not select a routine for change unless at least some elites—people with role-based authority—frame the existing routine as negatively affecting their role-specific goals. Roles also shape individuals’ frames. Because people are only partially exposed to interdependencies between routines in their dayto-day work, they may not be fully aware of the diverse impact that an existing routine can have on their goals. Proponents for change can use strategic framing to focus attention on interdependencies between routines to get elites to better see how an existing routine negatively affects their goals. They can also change elites’ goals by using strategic framing to focus attention on new and broader goals that the change in routine would promote

Effects of land cover on ecosystem services in Tanzania: A spatial assessment of soil organic carbon

AbstractThe multiple ecosystem services provided by healthy soil are well known and include soil carbon sequestration to mitigate climate change, a medium for plant and agricultural production and regulating the hydrologic cycle. Despite the wide recognition of the importance of these services, drivers of soil organic carbon (SOC) dynamics across various land uses in East Africa are poorly understood. The objectives of this study were threefold: to quantify SOC stocks across Tanzania; assess the effect of land cover and erosion on SOC; and investigate the relationship between inherent and dynamic soil properties under diverse land uses. The Land Degradation Surveillance Framework (LDSF) was used to assess the variability of ecological metrics at different spatial scales. SOC was quantified within and between different land cover types (forest, woodland, shrubland, grassland and cropland) in Tanzania. A total of 2052 soil samples from 1082–1000m2 plots were collected from seven 100-km2 sentinel sites in 2010. Composite soil samples were collected at each plot from two depths (0–20 and 20–50cm) and cumulative soil mass samples were collected to 100cm. Soil samples were analyzed using a combination of traditional analytical laboratory methods and mid-infrared spectroscopy (MIR). Model performance of MIR spectral predictions for carbon was good, with an R2 of >0.95 and RMSEP of 4.3gkg−1, when using an independent validation datasets. Woodland and cropland were the most frequently occurring vegetation structure types in the sampled sites, with 388 and 246 plots, respectively. Average topsoil OC (and range) was 12.4 (1.5–81.4) gCkg−1 (n=1082) and average subsoil OC (and range) was 7.3 (0.64–53.8) gCkg−1 (n=970) for the seven sites. Forested plots had the highest mean topsoil organic carbon concentrations (17.3gCkg−1) followed by cropland (13.3gCkg−1), for all sites included in the study, but with high levels of variability between sites. Soil mass at 30cm was measured and these data were used to calculate carbon stocks for the different land cover types. An approach based on remote sensing was explored for the mapping of SOC stocks at 30cm for Tanzania using Moderate Resolution Imaging Spectroradiometer (MODIS) imagery from 2012. Results indicate that the use of image reflectance for the mapping of SOC stocks has promising potential, with R2 values ranging from 0.77 to 0.81 and RMSEP values from 0.90 to 1.03kgm−2 for the three validation datasets. There is high utility of these maps for strategic land management interventions that prioritize ecosystem services

Urocortin 3 marks mature human primary and embryonic stem cell-derived pancreatic alpha and beta cells.

The peptide hormone Urocortin 3 (Ucn 3) is abundantly and exclusively expressed in mouse pancreatic beta cells where it regulates insulin secretion. Here we demonstrate that Ucn 3 first appears at embryonic day (E) 17.5 and, from approximately postnatal day (p) 7 and onwards throughout adult life, becomes a unifying and exclusive feature of mouse beta cells. These observations identify Ucn 3 as a potential beta cell maturation marker. To determine whether Ucn 3 is similarly restricted to beta cells in humans, we conducted comprehensive immunohistochemistry and gene expression experiments on macaque and human pancreas and sorted primary human islet cells. This revealed that Ucn 3 is not restricted to the beta cell lineage in primates, but is also expressed in alpha cells. To substantiate these findings, we analyzed human embryonic stem cell (hESC)-derived pancreatic endoderm that differentiates into mature endocrine cells upon engraftment in mice. Ucn 3 expression in hESC-derived grafts increased robustly upon differentiation into mature endocrine cells and localized to both alpha and beta cells. Collectively, these observations confirm that Ucn 3 is expressed in adult beta cells in both mouse and human and appears late in beta cell differentiation. Expression of Pdx1, Nkx6.1 and PC1/3 in hESC-derived Ucn 3(+) beta cells supports this. However, the expression of Ucn 3 in primary and hESC-derived alpha cells demonstrates that human Ucn 3 is not exclusive to the beta cell lineage but is a general marker for both the alpha and beta cell lineages. Ucn 3(+) hESC-derived alpha cells do not express Nkx6.1, Pdx1 or PC1/3 in agreement with the presence of a separate population of Ucn 3(+) alpha cells. Our study highlights important species differences in Ucn 3 expression, which have implications for its utility as a marker to identify mature beta cells in (re)programming strategies

The pursuit of organizational change : becoming and being an agent for change

Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, 2008."June 2008."Includes bibliographical references (leaves 138-148).This dissertation addresses two questions: How do employees become mobilized to initiate and drive change in organizations? How do managers draw on external and internal resources in introducing and sustaining change projects? I answer these questions using business process redesign (BPR) as a case of organizational change. To answer the first question I analyze the experiences of 57 employees selected to participate on one of seven change teams. I identify the amalgam of experiences through which employees, although not necessarily successful in changing their own organization, develop a commitment to working for change across organizations. In answering the second question, I consider how managers use the resources provided by promoters of BPR and the resources and circumstances of the firm. Drawing on data from the introduction of organizational change projects in five organizations and career interviews with 30 managers who began working on organizational change projects in the early 1990s, I find that the actors' relationships to the larger industry of BPR practitioners change with experience. Actors decouple themselves from the prescriptions, language, and tools provided by the BPR community and increasingly draw on their own experiences and local resources. There is one important exception. Organizational actors continue at relationship with the BPR community that allows them to sustain their ideological commitment to the principles of BPR. In answering the questions set out above, I reconnect isolated cases of organizational change with environmental forces and actors. I move between the experiences and struggles of organizational actors and the supports and possibilities offered up by actors in the economy-wide BPR industry. In creating this connection between organizational change and the environment, I reconceptualize change projects as more than a means of changing an organization.(cont.) They are sites of cultural production and reproduction. Whether or not organizations change, BPR projects have the potential to change people and produce actors who continue to reproduce BPR across organizations.by Ruthanne Huising.Ph.D

Diagnostic trials: a field guide

The Diagnostic Trials, conducted in Kenya, Malawi, Mali, Nigeria, and Tanzania, constitute a major part of Africa Soil Information Service agronomic activities. This guide provides a standard tool that is part of a structured approach for the diagnosis of soil health related constraints to crop production. It is intended for use by national and international agricultural research systems, development partners and extension services to ensure standard procedures in data collection that will feed to an Africa-wide database of diagnostic trials, allowing an increase in data density over time and an improvement of the reliability in the assessment of soil constraints and inferences

Soil quality assessment and management plans for IITA research farms, Nigeria: IITA Ibadan campus, Ikenne and Kano (Minjibir) stations

This document contains a summary of the observations and results of the IITA research farms soil assessment. This report also includes the proposed soil management plans for each of the research farms. The field observation data, soil and water laboratory results are presented in the Appendix