Temporal and spatial stability of Anopheles gambiae larval habitat distribution in Western Kenya highlands.

BACKGROUND: Localized mosquito larval habitat management and the use of larvicides have been proposed as important control tools in integrated malaria vector management programs. In order to optimize the utility of these tools, detailed knowledge of the spatial distribution patterns of mosquito larval habitats is crucial. However, the spatial and temporal changes of habitat distribution patterns under different climatic conditions are rarely quantified and their implications to larval control are unknown. RESULTS: Using larval habitat data collected in western Kenya highlands during both dry and rainy seasons of 2003-2005, this study analyzed the seasonal and inter-annual changes in the spatial patterns in mosquito larval habitat distributions. We found that the spatial patterns of larval habitats had significant temporal variability both seasonally and inter-annually. CONCLUSIONS: The pattern of larval habitats is extremely important to the epidemiology of malaria because it results in spatial heterogeneity in the adult mosquito population and, subsequently, the spatial distribution of clinical malaria cases. Results from this study suggest that larval habitat management activities need to consider the dynamic nature of malaria vector habitats

A study of the distribution and abundance of the adult malaria vector in western Kenya highlands

<p>Abstract</p> <p>Background</p> <p>A sharp rise in the malaria mortality rate has been observed recently in western Kenya. Malaria is transmitted by mosquito vectors. Malaria control strategies can be more successful if the distribution and abundance of mosquito vectors is predicted. However, how mosquito vectors are distributed in space remain poor understood, and this question is rarely studied using spatial methods. This study aims to provide a better understanding of the distribution and abundance of mosquito vectors. To achieve this objective, spatial and non-spatial methods were employed. The data on the distribution of adult mosquitoes, and mosquito breeding habitats in a study area in western Kenya, and environmental variables were analyzed.</p> <p>Results</p> <p>The models developed using spatial methods outperformed the models developed using non-spatial methods. Houses close to locations where mosquito breeding habitats were repeatedly observed had more abundant adult female mosquitoes. Distance to high-order streams was identified as an effective predictor for the distribution of adult mosquitoes.</p> <p>Conclusion</p> <p>The spatial method is more effective in modeling the distribution of adult mosquitoes than the non-spatial method. The results of this study can be used to facilitate decision-making related to mosquito surveillance and malaria prevention.</p

Technical note—On the relation between several discrete choice models

In this paper, we study the relationship between several well known classes of discrete choice models, i.e., the random utility model (RUM), the representative agent model (RAM), and the semiparametric choice model (SCM). Using a welfare-based model as an intermediate, we show that the RAM and the SCM are equivalent. Furthermore, we show that both models as well as the welfare-based model strictly subsume the RUM when there are three or more alternatives, while the four are equivalent when there are only two alternatives. Thus, this paper presents a complete picture of the relationship between these choice models. </jats:p

Recognition of the symplectic simple group PSp4(p) PSp_4(p) by the order and degree prime-power graph

Let $G$ be a finite group, $\operatorname{cd}(G)$ the set of all irreducible character degrees of $G$, and $\rho(G)$ the set of all prime divisors of integers in $\operatorname{cd}(G)$. For a prime $p$ and a positive integer $n$, let $n_p$ denote the $p$-part of $n$. The degree prime-power graph of $G$ is a graph whose vertex set is $V(G) = \left\{p^{e_p(G)} \mid p \in \rho(G)\right\}$, where $p^{e_p(G)} = \max \left\{n_p \mid n \in \operatorname{cd}(G)\right\}$, and there is an edge between distinct numbers $x, y \in V(G)$ if $x y$ divides some integer in $\operatorname{cd}(G)$. The authors have previously shown that some non-abelian simple groups can be uniquely determined by their orders and degree prime-power graphs. In this paper, the authors build on this work and demonstrate that the symplectic simple group $PSp_4(p)$ can be uniquely identified by its order and degree prime-power graph

Variation of Anxiety and Depression During a 3-Year Period as Well as Their Risk Factors and Prognostic Value in Postoperative Bladder Cancer Patients

BackgroundAnxiety and depression are commonly recognized and prognostically relevant in cancer patients. The aim of this study was to explore the 3-year longitudinal changes in anxiety and depression, their risk factors, and prognostic value in patients with bladder cancer.MethodsHospital Anxiety and Depression Scale for anxiety (HADS-A) and depression (HADS-D) scores of 120 postoperative bladder cancer patients and 100 healthy controls (HCs) were assessed. Additionally, the HADS-A and HADS-D scores of bladder cancer patients were determined at 1 year, 2 years, and 3 years post surgery.ResultsHADS-A score (7.7 ± 3.0 vs. 4.8 ± 2.6), anxiety rate (38.3% vs. 9.0%), HADS-D score (7.7 ± 3.3 vs. 4.3 ± 2.6), depression rate (40.0% vs. 11.0%), as well as anxiety degree and depression degree, were all increased in bladder cancer patients compared with HCs (all P &lt; 0.001). Besides, the HADS-A score gradually increased from baseline to 3 years (P = 0.004), while the anxiety rate, HADS-D score, and depression rate did not change significantly (all P &gt; 0.050). Gender, tumor size, marriage status, hypertension, diversity, and lymph node (LN) metastasis were associated with anxiety or depression in patients with bladder cancer (all P &lt; 0.050). Anxiety was associated with shortened overall survival (OS) (P = 0.024) but did not link with disease-free survival (DFS) (P = 0.201); depression was not correlated with either DFS or OS (both P &gt; 0.050).ConclusionThe prevalence and severity of anxiety and depression are high in patients with bladder cancer, which are influenced by gender, tumor features, marriage status, and hypertension; in addition, their correlation with survival is relatively weak

Genomic sequence and analysis of a vaccinia virus isolate from a patient with a smallpox vaccine-related complication

BACKGROUND: Vaccinia virus (VACV)-DUKE was isolated from a lesion on a 54 year old female who presented to a doctor at the Duke University Medical Center. She was diagnosed with progressive vaccinia and treated with vaccinia immune globulin. The availability of the VACV-DUKE genome sequence permits a first time genomic comparison of a VACV isolate associated with a smallpox vaccine complication with the sequence of culture-derived clonal isolates of the Dryvax vaccine. RESULTS: This study showed that VACV-DUKE is most similar to VACV-ACAM2000 and CLONE3, two VACV clones isolated from the Dryvax(® )vaccine stock confirming VACV-DUKE as an isolate from Dryvax(®). However, VACV-DUKE is unique because it is, to date, the only Dryvax(® )clone isolated from a patient experiencing a vaccine-associated complication. The 199,960 bp VACV-DUKE genome encodes 225 open reading frames, including 178 intact genes and 47 gene fragments. Between VACV-DUKE and the other Dryvax(® )isolates, the major genomic differences are in fragmentation of the ankyrin-like, and kelch-like genes, presence of a full-length Interferon-α/β receptor gene, and the absence of a duplication of 12 ORFs in the inverted terminal repeat. Excluding this region, the DNA sequence of VACV-DUKE differs from the other two Dryvax(® )isolates by less than 0.4%. DNA sequencing also indicated that there was little heterogeneity in the sample, supporting the hypothesis that virus from an individual lesion is clonal in origin despite the fact that the vaccine is a mixed population. CONCLUSION: Virus in lesions that result from progressive vaccinia following vaccination with Dryvax are likely clonal in origin. The genomic sequence of VACV-DUKE is overall very similar to that of Dryvax(® )cell culture-derived clonal isolates. Furthermore, with the sequences of multiple clones from Dryvax(® )we can begin to appreciate the diversity of the viral population in the smallpox vaccine

Landscape determinants and remote sensing of anopheline mosquito larval habitats in the western Kenya highlands

BACKGROUND: In the past two decades the east African highlands have experienced several major malaria epidemics. Currently there is a renewed interest in exploring the possibility of anopheline larval control through environmental management or larvicide as an additional means of reducing malaria transmission in Africa. This study examined the landscape determinants of anopheline mosquito larval habitats and usefulness of remote sensing in identifying these habitats in western Kenya highlands. METHODS: Panchromatic aerial photos, Ikonos and Landsat Thematic Mapper 7 satellite images were acquired for a study area in Kakamega, western Kenya. Supervised classification of land-use and land-cover and visual identification of aquatic habitats were conducted. Ground survey of all aquatic habitats was conducted in the dry and rainy seasons in 2003. All habitats positive for anopheline larvae were identified. The retrieved data from the remote sensors were compared to the ground results on aquatic habitats and land-use. The probability of finding aquatic habitats and habitats with Anopheles larvae were modelled based on the digital elevation model and land-use types. RESULTS: The misclassification rate of land-cover types was 10.8% based on Ikonos imagery, 22.6% for panchromatic aerial photos and 39.2% for Landsat TM 7 imagery. The Ikonos image identified 40.6% of aquatic habitats, aerial photos identified 10.6%, and Landsate TM 7 image identified 0%. Computer models based on topographic features and land-cover information obtained from the Ikonos image yielded a misclassification rate of 20.3–22.7% for aquatic habitats, and 18.1–25.1% for anopheline-positive larval habitats. CONCLUSION: One-metre spatial resolution Ikonos images combined with computer modelling based on topographic land-cover features are useful tools for identification of anopheline larval habitats, and they can be used to assist to malaria vector control in western Kenya highlands