Algebraic Identities and Query Optimization In a Parametric Model For Relational Temporal Databases

This paper presents algebraic identities and algebraic query optimization for a parametric model for temporal databases. The parametric model has several features not present in the classical model. In this model a key is explicitly designated with a relation and an operator is available to change the key. The algebra for the parametric model is three-sorted; it includes relational expressions that evaluate to relations, domain expressions that evaluate to time domains, and boolean expressions that evaluate to TRUE or FALSE. The identities in the parametric model are classified as weak identities and strong identities. Weak identities in this model are largely counterparts of the identities in classical relational databases. Rather than establishing weak identities from scratch, a meta inference mechanism, introduced in the paper, allows weak identities to be induced from their classical counterpart. On the other hand, the strong identities will be established from scratch. An algorithm for algebraic optimization to transform a query to an equivalent query that will execute more efficiently is presented

Clinical Findings and Pro-Inflammatory Cytokines in Dengue Patients in Western India: A Facility-Based Study

BACKGROUND: Descriptions of dengue immunopathogenesis have largely relied on data from South-east Asia and America, while India is poorly represented. This study characterizes dengue cases from Pune, Western India, with respect to clinical profile and pro-inflammatory cytokines. METHODOLOGY/PRINCIPAL FINDINGS: In 2005, 372 clinically suspected dengue cases were tested by MAC-ELISA and RT-PCR for dengue virus (DENV) aetiology. The clinical profile was recorded at the hospital. Circulating levels of IFN-gamma, TNF-alpha, IL-6, and IL-8 were assessed by ELISA and secondary infections were defined by IgM to IgG ratio. Statistical analysis was carried out using the SPSS 11.0 version. Of the 372 individuals, 221 were confirmed to be dengue cases. Three serotypes, DENV-1, 2 and 3 were co-circulating and one case of dual infection was identified. Of 221 cases, 159 presented with Dengue fever (DF) and 62 with Dengue hemorrhagic fever (DHF) of which six had severe DHF and one died of shock. There was a strong association of rash, abdominal pain and conjunctival congestion with DHF. Levels of IFN-gamma were higher in DF whereas IL-6 and IL-8 were higher in DHF cases (p<0.05). The mean levels of the three cytokines were higher in secondary compared to primary infections. Levels of IFN-gamma and IL-8 were higher in early samples collected 2-5 days after onset than late samples collected 6-15 days after onset. IFN-gamma showed significant decreasing time trend (p = 0.005) and IL-8 levels showed increasing trend towards significance in DHF cases (interaction p = 0.059). There was a significant association of IL-8 levels with thrombocytopenia and both IFN-gamma and IL-8 were positively associated with alanine transaminase levels. CONCLUSIONS/SIGNIFICANCE: Rash, abdominal pain and conjunctival congestion could be prognostic symptoms for DHF. High levels of IL-6 and IL-8 were shown to associate with DHF. The time trend of IFN-gamma and IL-8 levels had greater significance than absolute values in DHF pathogenesis

Large-Fiber Dysfunction in Diabetic Peripheral Neuropathy Is Predicted by Cardiovascular Risk Factors

OBJECTIVE Diabetic large–nerve fiber dysfunction, as measured by vibration perception threshold (VPT), predicts foot ulceration, amputation, and mortality. Thus, determination of modifiable risk factors is of great clinical importance. RESEARCH DESIGN AND METHODS We assessed 1,407 patients with type 1 diabetes and a normal VPT participating in the EURODIAB Prospective Complications Study, at baseline mean ± SD age of 32.7 ± 10.2 years with diabetes duration of 14.7 ± 9.3 years and follow-up of 7.3 ± 0.6 years. VPT was measured using biothesiometry on the right big toe and medial malleolus. An abnormal result was defined as >2 SD from the predicted mean for the patient s age. RESULTS An abnormal VPT was associated with an increased incidence of gangrene, amputation, foot ulceration, leg bypass or angioplasty, and mortality (P ≤ 0.02). The incidence of abnormal VPT was 24% over the 7.3-year follow-up. Duration of diabetes and A1C significantly influenced the incidence of abnormal VPT (P < 0.0001). After correction for these, established risk factors for cardiovascular disease (CVD), including male sex (P = 0.0004), hypertension (P < 0.0001), total cholesterol (P = 0.002), LDL cholesterol (P = 0.01), smoking (P < 0.0001), weight (P < 0.0001), and diabetes complications (retinopathy [P = 0.0001], nephropathy [P = 0.01], and autonomic neuropathy [P = 0.001]), were all found to be significant risk factors. A previous history of CVD doubled the incidence of abnormal VPT. CONCLUSIONS This prospective study indicates that cardiovascular risk factors predict development of large-fiber dysfunction, which may account for the high mortality rate in patients with an abnormal VPT, and emphasizes the importance of early determination of VPT to detect subclinical neuropathy and to address cardiovascular risk factors