Institutional fields as linked arenas: Inter-field resource dependence, institutional work and institutional change

Theories of institutional change have paid limited attention to the ways in which relations between institutional fields might facilitate or hinder institutional change. I introduce inter-field resource dependence as an important condition explaining institutional change between fields. Building on resource dependence theory, I conceptualize two dimensions of inter-field resource dependence: mutual dependence and power imbalance. I argue that these two dimensions have opposite effects on the likelihood of institutional change between fields. Mutual dependence between two fields increases the chances of institutional change by inducing actors in both the fields to work at creating new shared institutions in order to regulate their mutual dependence. Power imbalance between two fields decreases the chances of institutional change by inducing actors in the dominant field to work at maintaining existing institutions in order to preserve their power. Thus, different types of inter-field resource dependence motivate actors to undertake different forms of institutional work, which in turn shape the likelihood of institutional change between fields. Developing this core argument, I theorize that whether the institutional change occurring between two fields is radical or incremental is a function of the type of resource dependence linking the two fields; for example, when power imbalance is high, institutional change is unlikely but when it occurs it tends to be radical

Perceived institutional support and small venture performance: The mediating role of entrepreneurial persistence

YesThis article examines the entrepreneurial persistence of opportunity-motivated entrepreneurs in Ghana. Specifically, it develops a theoretical model focusing on the relationships among perceived institutional support, entrepreneurial persistence and small venture performance, including how entrepreneurial networks condition the relationship between institutional support and entrepreneurial persistence. Using time-lagged data from 373 opportunity-motivated entrepreneurs leading small ventures in Ghana, we find broad support for our hypotheses. The insights from our study provide an integrative understanding of the relationships among perceived institutional support, entrepreneurial persistence and venture performance in an adverse environment. Theoretical and practical implications are discussed

Oxygen uptake and denitrification in soil aggregates

A mathematical model of oxygen uptake by bacteria in agricultural soils is presented with the goal of predicting anaerobic regions in which denitrification occurs. In an environment with a plentiful supply of oxygen, microorganisms consume oxygen through normal respiration. When the local oxygen concentration falls below a threshold level, denitrification may take place leading to the release of nitrous oxide, a potent agent for global warming. A two-dimensional model is presented in which one or more circular soil aggregates are located at a distance below the ground-level at which the prevailing oxygen concentration is prescribed. The level of denitrification is estimated by computing the area of any anaerobic cores which may develop in the interior of the aggregates. The oxygen distribution throughout the model soil is calculated first for an aggregated soil for which the ratio of the oxygen diffusivities between an aggregate and its surround is small via an asymptotic analysis. Second, the case of a non-aggregated soil featuring one or more microbial hotspots, for which the diffusion ratio is arbitrary, is examined numerically using the boundary-element method. Calculations with multiple aggregates demonstrate a sheltering effect whereby some aggregates receive less oxygen than their neighbours. In the case of an infinite regular triangular network representing an aggregated soil, it is shown that there is an optimal inter-aggregate spacing which minimises the total anaerobic core area

The development and piloting of the graduate assessment of preparedness for practice (GAPP) questionnaire

Introduction Most new dental graduates in the UK begin their professional career following a year in dental foundation training (DFT). There has been little investigation of how prepared they feel for independent general dental practice across all four domains of the General Dental Council’s curriculum ‘Preparing for practice’. This paper describes the development of the Graduate Assessment of Preparedness for Practice (GAPP) questionnaire to address this. Methodology The GAPP questionnaire was developed and piloted using a cohort of educational supervisors (ESs) and foundation dentists (FDs). The questionnaire comprised three parts, the first of which collected respondent demographic data. The second was based on Preparing for practice and was used to develop 34 ‘competence areas’ and required a tick-box response on a 7‑category Likert Scale. The third comprised free text questions in order to further explore the subject’s responses. Results Pilot feedback was positive, the statements were felt to be clear and unambiguous, allowing them sufficient scope to state their position. The pilot study informed small cosmetic changes to the GAPP questionnaire and inclusion of a ‘comments’ column for respondents to qualify their responses. The pilot results indicated that both FDs and their ESs felt that at ten months of DFT, the FDs were very well prepared for independent general dental practice. Discussion The paper describes the important considerations relating to the reliability and validity of the GAPP questionnaire. Conclusions GAPP appears to be a suitable questionnaire to measure preparedness of new graduates with a degree of reliability and validity. The instrument is designed to be simple to complete and provides a useful analytical instrument for both self-assessment of competence and for wider use within dental education

An affordable, quality-assured community-based system for high-resolution entomological surveillance of vector mosquitoes that reflects human malaria infection risk patterns.

ABSTRACT: BACKGROUND: More sensitive and scalable entomological surveillance tools are required to monitor low levels of transmission that are increasingly common across the tropics, particularly where vector control has been successful. A large-scale larviciding programme in urban Dar es Salaam, Tanzania is supported by a community-based (CB) system for trapping adult mosquito densities to monitor programme performance. Methodology An intensive and extensive CB system for routine, longitudinal, programmatic surveillance of malaria vectors and other mosquitoes using the Ifakara Tent Trap (ITT-C) was developed in Urban Dar es Salaam, Tanzania, and validated by comparison with quality assurance (QA) surveys using either ITT-C or human landing catches (HLC), as well as a cross-sectional survey of malaria parasite prevalence in the same housing compounds. RESULTS: Community-based ITT-C had much lower sensitivity per person-night of sampling than HLC (Relative Rate (RR) [95% Confidence Interval (CI)] = 0.079 [0.051, 0.121], P < 0.001 for Anopheles gambiae s.l. and 0.153 [0.137, 0.171], P < 0.001 for Culicines) but only moderately differed from QA surveys with the same trap (0.536 [0.406,0.617], P = 0.001 and 0.747 [0.677,0.824], P < 0.001, for An. gambiae or Culex respectively). Despite the poor sensitivity of the ITT per night of sampling, when CB-ITT was compared with QA-HLC, it proved at least comparably sensitive in absolute terms (171 versus 169 primary vectors caught) and cost-effective (153US$versus 187US$ per An. gambiae caught) because it allowed more spatially extensive and temporally intensive sampling (4284 versus 335 trap nights distributed over 615 versus 240 locations with a mean number of samples per year of 143 versus 141). Despite the very low vectors densities (Annual estimate of about 170 An gambiae s.l bites per person per year), CB-ITT was the only entomological predictor of parasite infection risk (Odds Ratio [95% CI] = 4.43[3.027,7. 454] per An. gambiae or Anopheles funestus caught per night, P =0.0373). Discussion and conclusion CB trapping approaches could be improved with more sensitive traps, but already offer a practical, safe and affordable system for routine programmatic mosquito surveillance and clusters could be distributed across entire countries by adapting the sample submission and quality assurance procedures accordingly

The Environment of the Malnourished Child

capítulo de libro -- Universidad de Costa Rica, 1976The study of the relation of man to his environment in developing countries emphasizes the inevitable need for societies to recognize the true causes of infection, malnutrition, and poverty. The need is for improvement in the quality of human life in less developed nations, a recommendation easy to prescribe but difficult to accomplish. Although our pool of knowledge is incomplete, it is adequate to suggest ways to diminish infection, increase food production, utilize food more efficiently, improve education, and provide systems of justice to protect the classes most in need. The physical environment in tropical and subtropical regions, and the socioeconomic characteristics of the population inhabiting such regions, favor maintenance and transmission of a variety of viruses, bacteria, and parasites that make agricultural progress and social development difficult, and that contribute to poor fetal growth, nutrient wastage, and deficient postnatal physical growth. accounting for most of the childhood morbidity and mortality. In this regard. infections contribute indirectly to the overall food problem in a similar fashion as pests do in terms of food losses and spoilage. The overall effect could be comparable or greater than that resulting from an inadequate capacity to produce or to purchase the food needed. Thus, my objective has been to stress, within the whole environment, the importance of infection and the need to diminish it. Waysto control and prevent infection are readily known. They have to do with education of the population to improve personal and environmental hygiene. Economic investment is necessary to improve housing and water supply sYstems, waste disposal, and such preventive measures as immunization programs. Although such measures may appear expensive when first implemented, they have long-lasting effects and many require minimal expenditure once they are established. Large segments of the population stand to benefit, and other development interventions can then be introduced. However, these measures should not be implemented singly. They should be accompanied by community development, family planning, social legislation-in other words, the holistic approach to health and welfare. To do otherwise may aggravate the problem by stimulating demographic growth, perpetuating malnutrition and infection, and maintaining underdevelopmentUniversidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Characterization of immunoglobulin G antibodies to Plasmodium falciparum sporozoite surface antigen MB2 in malaria exposed individuals

<p>Abstract</p> <p>Background</p> <p>MB2 protein is a sporozoite surface antigen on the human malaria parasite <it>Plasmodium falciparum</it>. MB2 was identified by screening a <it>P. falciparum </it>sporozoite cDNA expression library using immune sera from a protected donor immunized via the bites of <it>P. falciparum</it>-infected irradiated mosquitoes. It is not known whether natural exposure to <it>P. falciparum </it>also induces the anti-MB2 response and if this response differs from that in protected individuals immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes. The anti-MB2 antibody response may be part of a robust protective response against the sporozoite.</p> <p>Methods</p> <p>Fragments of polypeptide regions of MB2 were constructed as recombinant fusions sandwiched between glutathione S-transferase and a hexa histidine tag for bacterial expression. The hexa histidine tag affinity purified proteins were used to immunize rabbits and the polyclonal sera evaluated in an <it>in vitro </it>inhibition of sporozoite invasion assay. The proteins were also used in immunoblots with sera from a limited number of donors immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes and plasma and serum obtained from naturally exposed individuals in Kenya.</p> <p>Results</p> <p>Rabbit polyclonal antibodies targeting the non-repeat region of the basic domain of MB2 inhibited sporozoites entry into HepG2-A16 cells <it>in vitro</it>. Analysis of serum from five human volunteers that were immunized via the bites of <it>P. falciparum </it>infected irradiated mosquitoes that developed immunity and were completely protected against subsequent challenge with non-irradiated parasite also had detectable levels of antibody against MB2 basic domain. In contrast, in three volunteers not protected, anti-MB2 antibodies were below the level of detection. Sera from protected volunteers preferentially recognized a non-repeat region of the basic domain of MB2, whereas plasma from naturally-infected individuals also had antibodies that recognize regions of MB2 that contain a repeat motif in immunoblots. Sequence analysis of eleven field isolates and four laboratory strains showed that these antigenic regions of the basic domain of the <it>MB2 </it>gene are highly conserved in parasites obtained from different parts of the world. Moreover, anti-MB2 antibodies also were detected in the plasma of 83% of the individuals living in a malaria endemic area of Kenya (n = 41).</p> <p>Conclusion</p> <p>A preliminary analysis of the human humoral response against MB2 indicates that it may be an additional highly conserved target for immune intervention at the pre-erythrocytic stage of <it>P. falciparum </it>life cycle.</p

Immunological mechanisms underlying protection mediated by RTS,S: a review of the available data

The RTS,S/AS candidate malaria vaccine has demonstrated efficacy against a variety of endpoints in Phase IIa and Phase IIb trials over more than a decade. A multi-country phase III trial of RTS,S/AS01 is now underway with submission as early as 2012, if vaccine safety and efficacy are confirmed. The immunologic basis for how the vaccine protects against both infection and disease remains uncertain. It is, therefore, timely to review the information currently available about the vaccine with regard to how it impacts the human-Plasmodium falciparum host-pathogen relationship. In this article, what is known about mechanisms involved in partial protection against malaria induced by RTS,S is reviewed

Taming trilogues: the EU's law-making process in a comparative perspective.

Trilogues have become the modus operandi of EU decision-making. They are an informal but institutionalised mechanism providing for in camera discussions of legislative texts between the three main EU decision-making institutions, with a view to securing legislative compromises. Trilogues present risks to an organ of parliamentary representation through their potential to depoliticise conflict and by reducing the accountability and transparency of the decision-making process. We examine how the European Parliament (EP) has responded to trilogues and what this response tells us about the development of the EP as an institutionalised organ of representative democracy. We compare these with arrangements for bicameral conflict resolution in the United States, where similar issues are presented by informal mechanisms of decision-making. We assess the institutionalisation of trilogues from a democratic perspective, highlighting achievements and future challenges, and the value of these findings for the ongoing reflection on the EP as a normal parliament and the role of informal institutions in EU law-making