103 research outputs found
Best performance JPA implementation choice
No full textBakalaura darbā tiek apskatīts ORM, kas ir ORM un kādu problēmu tas risina. Tiek apskatīts JPA, kā viens no ORM realizācijas slāņiem. Apskatītas JPA implementācijas, kas atbalsta pēdējo JPA 2.2 versiju, kādas JPA anotācijas izstrādātājs izmanto Java kodā, datubāzes atbalstam. Tiek veikta divu JPA implementāciju, EclipseLink un Hibernate, veiktspējas salīdzinājums. Praktiskajā darbā tiek apskatīts JPA implementāciju veiktspējas un izmantotās atmiņas salīdzinājums, kopā ar Java nemainīgo vaicājumu valodu (JPQL) pielietošanu. Tiek apskatīti atmiņas trūkumu risinājuma iespējas. Darba autors rekomendē izmantot Hibernate implementāciju un tikai izņēmuma gadījumā, kad vajag strādāt ar vienu tabulas lietotni, tad izmantot EclipseLinkThe bachelor's thesis examines what is ORM and what problem it solves. JPA is considered as one of the layers of ORM implementation. Thesis examines also JPA implementations that support the latest version of JPA - 2.2, which JPA annotations developer uses in Java code. Practical part consists of performance comparison of two JPA implementations EclipseLink and Hibernate. The practical part deals with the comparison of performance and memory usage of JPA implementations as well as usage of Java Persistence Query Language (JPQL). This part also includes possibilities of solving memory issues caused by JPA implementations. The author of the paper recommends using Hibernate implementation in all cases except one case when you need to work with one table applications where it is considered to use EclipseLink
Confirmed Malaria Cases Among Children Under Five with Fever and History of Fever Rural Western Tanzania.
No full textThe World Health Organization recommends that malaria treatment should begin with parasitological diagnosis. This will help to control misuse of anti-malarial drugs in areas with low transmission. The present study was conducted to assess the prevalence of parasitologically confirmed malaria among children under five years of age presenting with fever or history of fever in rural western Tanzania. A finger prick blood sample was obtained from each child, and thin and thick blood smears were prepared, stained with 10% Giemsa and examined under the light microscope. A structured questionnaire was used to collect each patient's demographic information, reasons for coming to the health center; and a physical examination was carried out on all patients. Fever was defined as axillary temperature ≥ 37.5°C. A total of 300 children with fever or a history of fever (1 or 2 weeks) were recruited, in which 54.3% (163/300, 95%CI, 48.7-59.9) were boys. A total of 76 (76/300, 25.3%, 95%CI, 22.8 - 27.8) of the children had fever. Based on a parasitological diagnosis of malaria, only 12% (36/300, 95%CI, 8.3-15.7) of the children had P. falciparum infection. Of the children with P. falciparum infection, 52.7% (19/36, 95%CI, 47.1-58.3) had fever and the remaining had no fever. The geometrical mean of the parasites was 708.62 (95%CI, 477.96-1050.62) parasites/μl and 25% (9/36, 95%CI, 10.9 -- 39.1) of the children with positive P. falciparum had ≥ 1001 parasites/μl. On Univariate (OR = 2.13, 95%CI, 1.02-4.43, P = 0.044) and multivariate (OR = 2.15, 95%CI, 1.03-4.49) analysis, only children above one year of age were associated with malaria infections. Only a small proportion of the children under the age of five with fever had malaria, and with a proportion of children having non-malaria fever. Improvement of malaria diagnostic and other causes of febrile illness may provide effective measure in management of febrile illness in malaria endemic areas
Challenges in malaria control in sub-Saharan Africa: the vaccine perspective
No full textUdgivelsesdato: 2008-OctMalaria is a life-threatening disease of public health importance, especially in sub-Saharan Africa. It is estimated that about 500 million cases of malaria occur annually and among these 1 million die annually. Children below five years and pregnant women are the most vulnerable groups. Several malaria control measures have been applied such as environmental improvements, use of insecticide impregnated nets, residual indoor spraying, early case detection and treatment with effective antimalarial drugs. However, the adaptation of vector and parasite has so far limited the effect of these interventions. The emergence of resistance against drugs and insecticides requires in response a steady stream of new interventions. Up to the beginning of this millennium, most sub-Saharan African countries have been using chloroquine (CQ) as the first-line antimalarial drug, which had to be replaced with sulphadoxine-pyrimethamine (SP) after resistant parasites had rendered CQ ineffective. Currently the first line treatment of malaria consists of combination therapy which includes an artemisinin derivative. The current approach appears robust but history has taught us to be alert and to expect resistance to emerge. There is a pressing need to develop and deploy complimentary strategies. Adding a protective vaccine to the existing control tools for malaria holds great promise yet no malaria vaccine has ever been licensed despite a large number of attempts. The complexity of malaria parasites and the ability of the parasite to suppress and evade immune responses are formidable challenges. Fortunately, there are several promising antimalarial vaccine candidates in the development pipeline. The most promising vaccine candidate is RTSS which is currently tested in various countries in sub-Saharan Africa, including two sites in Tanzania. There is a hope that malaria vaccines could be developed and deployed in malaria endemic communities. This article highlights the challenges of developing and deploying malaria vaccines
Immunophoretic rapid diagnostic tests as a source of immunoglobulins for estimating malaria sero-prevalence and transmission intensity.
No full textBACKGROUND: Sero-epidemiological methods are being developed as a tool for rapid assessment of malaria transmission intensity. Simple blood collection methods for use in field settings will make this more feasible. This paper describes validation of such a method, by analysing immunoglobulins from blood retained within immunophoretic rapid diagnostic tests (RDTs) for Plasmodium falciparum. RDTs are now widely used for the diagnosis of malaria and estimation of parasite rates, and this method represents a further use for these devices in malaria control. METHODS: Immunoglobulins eluted from RDTs, designed to detect parasite histidine rich protein-2 (HRP-2), were analysed by indirect ELISA for IgG recognizing the P. falciparum blood stage antigens merozoite surface protein-1(19) (MSP-1(19)) and apical membrane antigen-1 (AMA-1). Optimal storage conditions for RDTs were evaluated by comparing antibody responses from RDTs stored in dry or humid conditions at 4 degrees C or at ambient temperature (with or without air-conditioning) for 7, 31 or 70 days. Antibody levels estimated using 3,700 RDT samples from attendees at health facilities in North-eastern Tanzania were compared with contemporaneously collected filter paper blood spots (FPBS) and used to estimate seroconversion rates. RESULTS: Storage of RDTs at 4 degrees C was optimal for immunoglobulin recovery but short-term storage at ambient temperatures did not substantially affect anti-malarial IgG levels. Results from RDTs were comparable with those from FPBSs, for both antigens. RDT-generated titres tended to be slightly higher than those generated from FPBSs, possibly due to greater recovery of immunoglobulins from RDTs compared to filter paper. Importantly, however, RDT-based seroconversion rates, and hence serological estimates of malaria transmission intensity, agreed closely with those from FPBSs. CONCLUSION: RDTs represent a practical option for collecting blood for sero-epidemiological surveys, with potential cost and logistical advantages over filter paper and other blood collection methods. RDT-based seroepidemiology can be incorporated into routine monitoring of malaria endemicity, providing information to supplement parasite prevalence rates and generating rapid, robust assessment of malaria transmission intensity at minimal extra cost
Change in Composition of the Anopheles Gambiae Complex and its Possible Implications for the Transmission of Malaria and Lymphatic Filariasis in North-Eastern Tanzania.
No full textA dramatic decline in the incidence of malaria due to Plasmodium falciparum infection in coastal East Africa has recently been reported to be paralleled (or even preceded) by an equally dramatic decline in malaria vector density, despite absence of organized vector control. As part of investigations into possible causes for the change in vector population density, the present study analysed the Anopheles gambiae s.l. sibling species composition in north-eastern Tanzania. The study was in two parts. The first compared current species complex composition in freshly caught An. gambiae s.l. complex from three villages to the composition reported from previous studies carried out 2-4 decades ago in the same villages. The second took advantage of a sample of archived dried An. gambiae s.l. complex specimens collected regularly from a fourth study village since 2005. Both fresh and archived dried specimens were identified to sibling species of the An. gambiae s.l. complex by PCR. The same specimens were moreover examined for Plasmodium falciparum and Wuchereria bancrofti infection by PCR. As in earlier studies, An. gambiae s.s., Anopheles merus and Anopheles arabiensis were identified as sibling species found in the area. However, both study parts indicated a marked change in sibling species composition over time. From being by far the most abundant in the past An. gambiae s.s. was now the most rare, whereas An. arabiensis had changed from being the most rare to the most common. P. falciparum infection was rarely detected in the examined specimens (and only in An. arabiensis) whereas W. bancrofti infection was prevalent and detected in all three sibling species. The study indicates that a major shift in An. gambiae s.l. sibling species composition has taken place in the study area in recent years. Combined with the earlier reported decline in overall malaria vector density, the study suggests that this decline has been most marked for An. gambiae s.s., and least for An. arabiensis, leading to current predominance of the latter. Due to differences in biology and vectorial capacity of the An. gambiae s.l. complex the change in sibling species composition will have important implications for the epidemiology and control of malaria and lymphatic filariasis in the study area
Analysis of Erythrocyte Invasion Mechanisms of Plasmodium falciparum Clinical Isolates Across 3 Malaria-Endemic Areas in Ghana.
No full textBACKGROUND: Plasmodium falciparum invades human erythrocytes by using an array of ligands that interact with several receptors, including sialic acid (SA), complement receptor 1 (CR1), and basigin. We hypothesized that in malaria-endemic areas, parasites vary invasion pathways under immune pressure. Therefore, invasion mechanisms of clinical isolates collected from 3 zones of Ghana with different levels of endemicity (from lowest to highest, Accra, Navrongo, and Kintampo) were compared using standardized methods. METHODS: Blood samples were collected from children aged 2-14 years in whom malaria was diagnosed, and erythrocyte invasion phenotypes were determined using the enzymes neuraminidase, chymotrypsin, and trypsin, which differentially cleave receptors from the erythrocyte surface. In addition, antibodies against CR1 and basigin were used to determine the contributions of these receptors to invasion. Gene expression levels of P. falciparum invasion ligands were also examined. RESULTS: The parasites generally expressed SA-independent invasion phenotypes across the malaria-endemic areas, with parasites from Kintampo showing the highest invasion rates in neuraminidase-treated erythrocytes. CR1 was a major mediator of SA-independent invasion, while basigin was essential for both SA-dependent and SA-independent invasion mechanisms. Furthermore, expression of the basigin ligand PfRh5 was the best predictor of donor parasitemia. CONCLUSIONS: Erythrocyte invasion phenotypes expressed by P. falciparum are influenced by endemicity levels, and the PfRh5-basigin pathway is a potential vaccine target
Fabrication and characteriation of Josephson parametric amplifiers
No full textIn this thesis, a we have designed and fabricated a Josephson Parametric Amplifier (JPA) using a new double-angle evaporation method without a Dolan bridge. We have found and resolved several issues in the fabrication procedure, but it requires further tuning before being fully functional. We have also simulated the behaviour of a general parametric amplifier with an additional Duffing non-linear term, and found that this term appears to limit the oscillation amplitude. We have attempted to characterize Josephson junctions fabricated with the new double-angle evaporation procedure, but without much success. Using a different fabrication method, a JPA was made and successfully characterized. The maximum measured gain is 16 dB, with a bandwidth of 1 MHz. The noise temperature is comparable to the cryostat temperature of 250 mK, but it was not characterized accurately
Event triggered non-cooperative game theory for demand side management in smart grids
No full textOver the past decade, a new concept for the power grid called the smart grid emerged, to enable two way energy transport and communication. With this new smart grid architecture many opportunities for control methods arise. While this can improve the efficiency of the power grid, all these methods require communication, which is a limited resource. In this thesis I focus on one particular concept of the smart grid called demand side management. One of the possible ways to apply demand side management is by use of game theory. By molding the game into a specific kind of game called potential game, similarities between the convergence of these potential games and the methods used in event triggered control, which is a method to reduce communication in networked control systems, can be observed. By using these similarities the principles of event triggered control can be applied to potential games. This way I create an event triggered potential game, which reduces the amount of communication required to reach the Nash equilibrium. To accomplish this I design two algorithms for event triggered potential games. One in which the decision on whether or not to communicate is made in a centralized way and one in which this occurs in a decentralized way, where all players decide for themselves when to communicate.Mechanical Engineering | Systems and Contro
Efficacy of RTS,S malaria vaccines: individual-participant pooled analysis of phase 2 data.
No full textBACKGROUND: The efficacy of RTS,S/AS01 as a vaccine for malaria is being tested in a phase 3 clinical trial. Early results show significant, albeit partial, protection against clinical malaria and severe malaria. To ascertain variations in vaccine efficacy according to covariates such as transmission intensity, choice of adjuvant, age at vaccination, and bednet use, we did an individual-participant pooled analysis of phase 2 clinical data. METHODS: We analysed data from 11 different sites in Africa, including 4453 participants. We measured heterogeneity in vaccine efficacy by estimating the interactions between covariates and vaccination in pooled multivariable Cox regression and Poisson regression analyses. Endpoints for measurement of vaccine efficacy were infection, clinical malaria, severe malaria, and death. We defined transmission intensity levels according to the estimated local parasite prevalence in children aged 2-10 years (PrP₂₋₁₀), ranging from 5% to 80%. Choice of adjuvant was either AS01 or AS02. FINDINGS: Vaccine efficacy against all episodes of clinical malaria varied by transmission intensity (p=0·001). At low transmission (PrP₂₋₁₀ 10%) vaccine efficacy was 60% (95% CI 54 to 67), at moderate transmission (PrP₂₋₁₀ 20%) it was 41% (21 to 57), and at high transmission (PrP₂₋₁₀ 70%) the efficacy was 4% (-10 to 22). Vaccine efficacy also varied by adjuvant choice (p<0·0001)--eg, at low transmission (PrP₂₋₁₀ 10%), efficacy varied from 60% (95% CI 54 to 67) for AS01 to 47% (14 to 75) for AS02. Variations in efficacy by age at vaccination were of borderline significance (p=0·038), and bednet use and sex were not significant covariates. Vaccine efficacy (pooled across adjuvant choice and transmission intensity) varied significantly (p<0·0001) according to time since vaccination, from 36% efficacy (95% CI 24 to 45) at time of vaccination to 0% (-38 to 38) after 3 years. INTERPRETATION: Vaccine efficacy against clinical disease was of limited duration and was not detectable 3 years after vaccination. Furthermore, efficacy fell with increasing transmission intensity. Outcomes after vaccination cannot be gauged accurately on the basis of one pooled efficacy figure. However, predictions of public-health outcomes of vaccination will need to take account of variations in efficacy by transmission intensity and by time since vaccination. FUNDING: Medical Research Council (UK); Bill & Melinda Gates Foundation Vaccine Modelling Initiative; Wellcome Trust
Overview modelling gas production-induced seismicity mechanisms
No full textSeveral studies have been carried out at Delft University of Technology in order to analyse seismicity that might be related to gas production. An overview will be given in this paper. Models show that the sensitivity for fault activation due to differential compaction evidently depends on the fault-reservoir geometry. This behaviour is supported by several subsequent case studies of fault behaviour in producing gas reservoirs. Examples of such reservoirs, presented in this paper, are Eleveld and Bergermeer in the Netherlands. A comprehensive study about an anticline-shaped reservoir concluded also in activation of a normal fault at reservoir level as dominant mechanism. In another study, the effects of gas storage on the relationship between pore pressure variations and fault slip are investigated. The results from this numerical modelling are that during the initial production phase, fault slip might occur locally, due to compaction of the reservoir, and that no significant amounts of additional slip occur when the reservoir is subjected to alternating injection/extraction periods.Old - CITG Section Engineering Geolog
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