266 research outputs found
Trap Tree and Interception Trap Techniques for Management of Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) in Nursery Production Get access Arrow
The majority of wood-boring ambrosia beetles are strongly attracted to ethanol, a behavior which could be exploited for management within ornamental nurseries. A series of experiments was conducted to determine if ethanol-based interception techniques could reduce ambrosia beetle pest pressure. In two experiments, trap trees injected with a high dose of ethanol were positioned either adjacent or 10–15 m from trees injected with a low dose of ethanol (simulating a mildly stressed tree) to determine if the high-dose trap trees could draw beetle attacks away from immediately adjacent stressed nursery trees. The high-ethanol-dose trees sustained considerably higher attacks than the low-dose trees; however, distance between the low- and high-dose trees did not significantly alter attack rates on the low-dose trees. In a third experiment, 60-m length trap lines with varying densities of ethanol-baited traps were deployed along a forest edge to determine if immigrating beetles could be intercepted before reaching sentinel traps or artificially stressed sentinel trees located 10 m further in-field. Intercept trap densities of 2 or 4 traps per trap line were associated with fewer attacks on sentinel trees compared to no traps, but 7 or 13 traps had no impact. None of the tested intercept trap densities resulted in significantly fewer beetles reaching the sentinel traps. The evaluated ethanol-based interception techniques showed limited promise for reducing ambrosia beetle pressure on nursery trees. An interception effect might be enhanced by applying a repellent compound to nursery trees in a push–pull strategy
Rethinking Sudan Studies: A Post-2011 Manifesto
Abstract
This essay appraises “Sudan Studies” following the 2011 secession of South Sudan. It asks two questions. First, what has Sudan Studies been as a colonial and postcolonial field of academic inquiry and how should or must it change? Second, should we continue to write about a single arena of Sudan Studies now that Sudan has split apart? The authors advance a “manifesto” for Sudan Studies by urging scholars to map out more intellectual terrain by attending to non-elite actors and women; grass-roots and local history; the environment and the arts; oral sources; and interdisciplinary studies of culture, politics, and society. They propose that scholars can transcend the changing boundaries of the nation-state, and recognize connections forged through past and present migrations and contacts, by studying the Sudan as a zone rather than a fixed country. Finally, in their introduction to this bilingual special issue, they highlight the increasing relevance of French scholarship to the endeavor of rethinking Sudan Studies.
Résumé
Cet essai évalue la situation des « études soudanaises » après la sécession du Soudan du Sud. Il pose deux questions. La première : En quoi ont consisté les études soudanaises en tant que domaine colonial et postcolonial de recherche universitaire et dans quelle mesure doivent-elles changer, si tant est qu\u27elles doivent changer ? La seconde : Devrions-nous continuer à baser nos écrits sur un domaine unique d\u27études soudanaises maintenant que le Soudan est divisé ? Les auteurs proposent un « manifeste » pour les études soudanaises en exhortant les experts à cartographier un terrain intellectuel élargi en s\u27intéressant aux acteurs ne faisant pas partie des élites et des femmes ; à l\u27histoire de la base populaire et locale ; à l\u27environnement et à l\u27art ; aux sources orales ; et aux études interdisciplinaires portant sur la culture, la politique et la société. Ils avancent que les chercheurs peuvent aller au-delà des frontières en mutation de l\u27État-nation et reconnaitre les connexions établies grâce aux migrations et aux contacts passés et présents en étudiant le Soudan comme zone plutôt que comme un pays fixe. Enfin, dans leur introduction à ce numéro bilingue spécial, ils mettent en relief la pertinence croissance des travaux universitaires français dans le cadre de l\u27initiative visant à repenser les études soudanaises
Gene Knock-Outs of Inositol 1,4,5-Trisphosphate Receptors Types 1 and 2 Result in Perturbation of Cardiogenesis
Rs in cardiogenesis remain unclear.Rs mimicked the phenotype of the AV valve defect that result from the inhibition of calcineurin, and it could be rescued by constitutively active calcineurin.Rs in cardiogenesis in part through the regulation of calcineurin-NFAT signaling
Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy
Background
A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets.
Methods
Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis.
Results
A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001).
Conclusion
We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
Distribution of Mycobacterium ulcerans in Buruli Ulcer Endemic and Non-Endemic Aquatic Sites in Ghana
Mycobacterium ulcerans, the causative agent of Buruli ulcer, is an emerging environmental bacterium in Australia and West Africa. The primary risk factor associated with Buruli ulcer is proximity to slow moving water. Environmental constraints for disease are shown by the absence of infection in arid regions of infected countries. A particularly mysterious aspect of Buruli ulcer is the fact that endemic and non-endemic villages may be only a few kilometers apart within the same watershed. Recent studies suggest that aquatic invertebrate species may serve as reservoirs for M. ulcerans, although transmission pathways remain unknown. Systematic studies of the distribution of M. ulcerans in the environment using standard ecological methods have not been reported. Here we present results from the first study based on random sampling of endemic and non-endemic sites. In this study PCR-based methods, along with biofilm collections, have been used to map the presence of M. ulcerans within 26 aquatic sites in Ghana. Results suggest that M. ulcerans is present in both endemic and non-endemic sites and that variable number tandem repeat (VNTR) profiling can be used to follow chains of transmission from the environment to humans. Our results suggesting that the distribution of M. ulcerans is far broader than the distribution of human disease is characteristic of environmental pathogens. These findings imply that focal demography, along with patterns of human water contact, may play a major role in transmission of Buruli ulcer
Juxtaposing a cultural reading of landscape with institutional boundaries: the case of the Masebe Nature Reserve, South Africa
The article explores theoretically the juxtaposition of local stories about landscape with institutional arrangements and exclusionary practices around a conservation area in South Africa. The Masebe Nature Reserve is used as a case study. The article argues that the institutional arrangements in which the nature reserve is currently positioned are too static, and consequently exclusionary, in their demarcation of boundaries. This stifles local communities’ sense of belonging to these landscapes. Hence, they strongly resent and feel alienated by the nature reserve. Their opposition and alienation often manifests in poaching. The empirical material is based on how local people living adjacent to the Masebe Nature Reserve have historically named and interpreted the area’s impressive sandstone mountains, in the process creating a sense of belonging. Juxtaposing this mostly tranquil cultural reading of the landscape to the institutional practices of boundary demarcation gives the analysis an immediate critical edge regarding issues of social justic
Improved Protective Efficacy of a Species-Specific DNA Vaccine Encoding Mycolyl-Transferase Ag85A from Mycobacterium ulcerans by Homologous Protein Boosting
Vaccination with plasmid DNA encoding Ag85A from M. bovis BCG can partially protect C57BL/6 mice against a subsequent footpad challenge with M. ulcerans. Unfortunately, this cross-reactive protection is insufficient to completely control the infection. Although genes encoding Ag85A from M. bovis BCG (identical to genes from M. tuberculosis) and from M. ulcerans are highly conserved, minor sequence differences exist, and use of the specific gene of M. ulcerans could possibly result in a more potent vaccine. Here we report on a comparison of immunogenicity and protective efficacy in C57BL/6 mice of Ag85A from M. tuberculosis and M. ulcerans, administered as a plasmid DNA vaccine, as a recombinant protein vaccine in adjuvant or as a combined DNA prime-protein boost vaccine. All three vaccination formulations induced cross-reactive humoral and cell-mediated immune responses, although species-specific Th1 type T cell epitopes could be identified in both the NH2-terminal region and the COOH-terminal region of the antigens. This partial species-specificity was reflected in a higher—albeit not sustained—protective efficacy of the M. ulcerans than of the M. tuberculosis vaccine, particularly when administered using the DNA prime-protein boost protocol
Glucocorticoids in T cell apoptosis and function
Glucocorticoids (GCs) are a class of steroid hormones which regulate a variety of essential biological functions. The profound anti-inflammatory and immunosuppressive activity of synthetic GCs, combined with their power to induce lymphocyte apoptosis place them among the most commonly prescribed drugs worldwide. Endogenous GCs also exert a wide range of immunomodulatory activities, including the control of T cell homeostasis. Most, if not all of these effects are mediated through the glucocorticoid receptor, a member of the nuclear receptor superfamily. However, the signaling pathways and their cell type specificity remain poorly defined. In this review, we summarize our present knowledge on GC action, the mechanisms employed to induce apoptosis and the currently discussed models of how they may participate in thymocyte development. Although our knowledge in this field has substantially increased during recent years, we are still far from a comprehensive picture of the role that GCs play in T lymphocytes
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