100,776 research outputs found
Dose-response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato.
No full textBACKGROUND: Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. METHODS: Dose-response and standardized field tests were implemented following standard procedures of the World Health Organization's Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. RESULTS: Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77% of eggs laid by females exposed to 0.018 ppm ai failed to hatch, whilst 98% of eggs laid by females exposed to 0.09 ppm ai did not hatch. CONCLUSION: Anopheles gambiae s.s. and An. arabiensis are highly susceptible to Sumilarv®0.5G at very low dosages. The persistence of this granule formulation in treated habitats under standardized field conditions and its sub-lethal impact, reducing the number of viable eggs from adults emerging from treated ponds, enhances its potential as malaria vector control tool. These unique properties warrant further field testing to determine its suitability for inclusion in malaria vector control programmes
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Ecology and Epidemiology of Integrated Malaria Vector Management in Dar es Salaam, Tanzania
No full textMalaria remains one of the major contributors to the global burden of disease with approximately 70% of the clinical malaria attacks occurring in sub-Saharan Africa. Sub- Saharan Africa has the highest risk as ideal climatic conditions for transmission coincide with occurrence of some of the most efficient malaria vectors, namely Anopheles gambiae s.s., Anopheles arabiensis and Anopheles funestus.. Even though it is estimated that by the year 2030 more than 50% of the African population will live in towns and cities, relatively little is known about urban malaria epidemiology, larval ecology and adult mosquito behaviour. Although integrated malaria control programs including environmental management and larviciding have proven successful before the Global Eradication Campaign started in 1955, they were neglected after the invention of DDT. Lately interest into these control measures has revived but it remains to be determined whether they are feasible and cost-effective in urban Africa. The overall goal of the research presented in this thesis was to enhance current understanding of urban malaria epidemiology and ecology and to take an in-depth look at the effectiveness of larviciding with Bacillus thuringiensis (Bti) in the context of the Urban Malaria Control Program (UMCP) in Dar es Salaam, Tanzania. Our findings are based on data derived from the first 3 years of the UMCP, where data collection started in March 2004. The project area includes 5 wards in each of the 3 municipalities which consist of 67 mitaa covering an area of 55 km2 in which 611,871 people lived during the population census of 2002. Achieving the UMCPs objectives fundamentally relies on three component activities: 1) Mapping and surveillance of potential Anopheles breeding sites, 2) Monitoring of adult mosquito densities, and 3) Household surveys with questionnaires and blood smears testing for malaria parasite infection. In the third year of the UMCP, beginning in March 2006, the routine application of the microbial larvicides Bti in open habitats and Bs in closed habitats was initiated in 3 of the 15 wards in the study area, adding to existing interventions such as bednets, house screening, ceiling boards, repellents, spray and coils. At the same time a detailed survey of mosquito biting behaviour, human behaviour and domestic protection measures was conducted in 12 Ten Cell Units (TCU), the smallest subunit of local government in Tanzania, which presented the highest An. gambiae s.l. densities during the early period of the UMCP surveillance system. Human landing catch (HLC) was conducted in 216 houses on an hourly basis indoors and outdoors from 6 pm till 7 am and residents were interviewed about their sleeping behaviour, where they spend their evenings and what kind of preventive measures against malaria they use. Personal protection of an insecticide treated net (ITN) was evaluated using an extension of a recently developed mathematical model. Overall An. gambiae s.l. exhibited a classical hourly biting pattern. In contrast one of the complex’s component sibling species, namely An. arabiensis, had an early biting peak before 10 pm. Both sibling species, namely An. gambiae s.s. and An. arabiensis, as well as An. funestus and An. coustani were highly exophagic. This behaviour led to a reduced personal protection against exposure to An. gambiae s.s. by ITNs which conferred 59% reduction of exposure in Dar es Salaam compared to 70% in rural Tanzania. An. arabiensis is a vector of only modest importance in Dar es Salaam which is fortunate because ITNs only conferred 38% protection against exposure to this species of mosquito. ITNs conferred slightly less protection against exposure to malaria vectors in good quality houses. This is mainly because people living in good houses tend to spend more time indoors before they go to bed. An. gambiae s.l. is the most important vector in Dar es Salaam , responsible for an EIR (entomological inoculation rate) of 1.00 infectious bites per person per year whereas An. funestus has an EIR of 0.13. Surprisingly, An. coustani also acts as a notable vector in Dar es Salaam with an EIR of 0.20 infectious bites per person per year. Malaria transmission is seasonal with two peaks of malaria prevalence during and after the two rainy seasons. Malaria prevalence was only related to EIR in children under 5 years of age, with a classical ageprevalence distribution similar to most of rural Africa. Malaria prevalence steadily declined from 2004 onwards as the use of window screenings, ceiling boards and more effective drugs like amodiaquine and artemisin-based drugs increased. ITNs (prevalence reduction estimate 20%, 95% CI 0%-36%; P=0.060; year 1) and ceiling boards (prevalence reduction estimate 22%, 95% CI 3%-38%; P=0.026; year 2) conferred modest personal protection and reduced malaria prevalence by approximately one fifth. By comparison, a much greater reduction (prevalence reduction estimate 50%, 95% CI 20%-64%; P=0.002) of malaria prevalence was achieved by larviciding with Bti. This was mainly achieved through major reductions of An. gambiae during July and August when most of the sporozoite infected mosquitoes were caught, combined with all-year-round suppression of the secondary vectors, namely An. funestus and An. coustani. This major achievement was only possible through the novel surveillance and staff management procedures developed by the UMCP to enable effective community based implementation in a decentralized manner. Standards of the surveillance improved greatly after the onset of the program with realized reaction times to vector surveillance at observations being one day, week and month at ward, municipality and city level, respectively. These results of changing biting behaviour of the main malaria vectors in urban settings and the therefore lower but still useful personal protection offered by ITNs call for additional complementary vector control methods such as environmental management or larviciding. The UMCP demonstrated that major reductions in malaria prevalence can be achieved through routine application of microbial larvicides with its new practical management and surveillance system. As these represent the early results of the program, we expect substantial improvement with time and investment. Here we demonstrated for the first time since before the Global Eradication Campaign era, a success story of a malaria control program integrating larviciding, which could be easily adapted by other African cities as a cost-effective option for malaria prevention
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
Measuring industry-science links through inventor-author relations: A profiling method
No full textIn this pilot study we examine the performance of text-based profiling in recovering a set of validated inventor-author links. In a first step we match patents and publications solely based on their similarity in content. Next, we compare inventor and author names on the highest ranked matches for the occurrence of name matches. Finally, we compare these candidate matches with the names listed in a validated set of inventor-author names. Our text-based profile methodology performs significantly better than a random matching of patents and publications, suggesting that text-based profiling is a valuable complementary tool to the name searches used in previous studies.innovation; industry-science links; text-based profiling;
Wave turbulence of a rotating array of quantized vortices in the T → 0 temperature limit
No full textThe dynamics of quantized vortices in the zero temperature limit is currently of great interest, particularly in the case of the Fermi superfluid He-B. Here we study wave turbulence, generated by the librating motion of a rotating cylindrical container filled with He-B, in the limit of vanishing viscous forces at temperatures . The polarization of the quantized vortices with respect to the axis of rotation is measured using non-invasive NMR techniques. We observe a decrease of the polarization when the librating motion is started, and a two-stage relaxation process when the modulation of the rotation velocity is stopped. The first relaxation process is associated with the dissipation of large-scale flow stored in inertial waves and the solid body rotation of the vortex array. From the decay of these energy reservoirs we determine the rate of energy dissipation of large-scale flow. The later second process is related to the relaxation of Kelvin waves on individual vortices. This process is monitored by the recovery of the polarization. The existence of a Kelvin wave cascade at the lowest temperatures is currently a central open question. We supply some evidence for the cascade
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
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