The use of correspondence analysis in building loglinear models

Data collected in the biomedical and social sciences by means of questionnaires is in most instances qualitative in nature. Such data, typically set out in the form of (multi-dimensional) contingency tables, is usually subjected to hypothesis testing in order to assess the interrelationships between the questions. Prior to undertaking confirmatory procedures, we argue that exploratory techniques should be used to gain a "feel" for the data. Correspondence Analysis (an exploratory data analysis procedure) and Log-linear Model building (a confirmatory data analysis procedure) are discussed before an investigation is undertaken to ascertain whether they can be used in conjunction. We found that correspondence analysis : (i) detects questions that are "strictly" independent/unrelated, (ii) detects pairwise relationships between questions (2-factor interactions) and thus can be used to suggest a splitting of large data sets into two or more subsets of questions that are independent, each of which can be analysed separately, and (iii) cannot be used to select log-linear models in general because it does not detect higher order interactions

Performance Evaluation with Stochastic Discount Factors

We study the use of stochastic discount factor (SDF) models in evaluating the investment performance of portfolio managers. By constructing artificial mutual funds with known levels of investment ability, we evaluate a large set of SDF models. We find that the measures of performance are not highly sensitive to the SDF model, and that most of the models have a mild negative bias when performance is neutral. We use the models to evaluate a sample of U.S. equity mutual funds. Adjusting for the observed bias, we find that the average mutual fund has enough ability to cover its transactions costs. Extreme funds are more likely to have good rather than poor risk adjusted performance. Our analysis also reveals a number of implementation issues relevant to other applications of SDF models.

Turmeric and black pepper spices decrease lipid peroxidation in meat patties during cooking.

Spices are rich in natural antioxidants and have been shown to be potent inhibitors of lipid peroxidation during cooking of meat. Turmeric contains unique conjugated curcuminoids with strong antioxidant activity. Piperine, one of the main constituents of black pepper, is known to increase the bioavailability of curcuminoids in mouse and human studies when consumed with turmeric. We investigated whether adding black pepper to turmeric powder may further inhibit lipid peroxidation when added to meat patties prior to cooking. The addition of black pepper to turmeric significantly decreased the lipid peroxidation in hamburger meat. When investigating the antioxidant activity of the main chemical markers, we determined that piperine did not exhibit any antioxidant activity. Therefore, we conclude that other black pepper ingredients are responsible for the increased antioxidant activity of combining black pepper with turmeric powder

Limitations of MTT and MTS-Based Assays for Measurement of Antiproliferative Activity of Green Tea Polyphenols

The chemopreventive effect of green tea polyphenols, such as (-)-epigallocatechin-3-gallate (EGCG), has been well demonstrated in cell culture studies. However, a wide range of IC(50) concentrations has been observed in published studies of the anti-proliferative activity of EGCG from different laboratories. Although the susceptibility to EGCG treatment is largely dependent on cancer cell type, the particular cell viability and proliferation assays utilized may significantly influence quantitative results reported in the literature.We compared five widely used methods to measure cell proliferation and viability after EGCG treatment using LNCaP prostate cancer cells and MCF-7 breast cancer cells. Both methods using dyes to quantify adenosine triphosphate (ATP) and deoxynucleic acid (DNA) showed accuracy in the measurement of viable cells when compared to trypan blue assay and results showed good linear correlation (r = 0.95). However, the use of MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) as indicators of metabolically active mitochondria overestimated the number of viable cells by comparison with the ATP, DNA, or trypan blue determinations. As a result, the observed IC(50) concentration of EGCG was 2-fold higher using MTT and MTS compared to dyes quantifying ATP and DNA. In contrast, when cells were treated with apigenin MTT and MTS assays showed consistent results with ATP, DNA, or trypan blue assays.These results demonstrate that MTT and MTS -based assays will provide an underestimation of the anti-proliferative effect of EGCG, and suggest the importance of careful evaluation of the method for in vitro assessment of cell viability and proliferation depending on the chemical nature of botanical supplements

COMPARISON OF ANGIOTENSIN RECEPTOR BLOCKER ALONE AND IN COMBINATION WITH VITAMIN D ANALOGUE IN REDUCING PROTEINURIA IN DIABETIC NEPHROPATHY PATIENTS

Objective: This study was designed to determine the synergistic effect of vitamin D analog added to angiotensin receptor blocker in reducing proteinuria in diabetic nephropathy patients. Methods: A randomized, open label, prospective, parallel assignment, comparative study included 50 patients with diabetic nephropathy who had a spot protein to creatinine ratio (PCR) of 100 - 1000 mg/g creatinine. Patients were randomized to receive treatment with either telmisartan 40 mg or calcitriol 0.25 mcg for a period of 12 weeks. The primary end point was the difference in the spot urinary PCR between the groups at 12 weeks. The secondary endpoints are change in Blood Pressure (BP), serum creatinine and glomerular filtration rate (GFR). Results: The primary end point of the study was reduced by 43.2% with telmisartan and 77.049% with telmisartan and calcitriol treatment (P= 0.0001) during 12 week periods. In the secondary end points, there were no significant differences. Conclusion: Hence, this study concludes that treatment with both calcitriol and telmisartan offers synergistic renoprotection

Runaway blue main-sequence stars at high Galactic latitudes. Target selection with Gaia and spectroscopic identification

Motivated by the historical identification of runaway main-sequence (MS) stars of early spectral type at high Galactic latitudes, we test the capability of Gaia at identifying new such stars. We have selected ~2300 sources with Gaia magnitudes of GBP - GRP < 0.05, compatible with the colors of low-extinction MS stars earlier than mid-A spectral type, and obtained low-resolution optical spectroscopy for 48 such stars. By performing detailed photometric and spectroscopic analyses, we derive their atmospheric and physical parameters (effective temperature, surface gravity, radial velocity, interstellar reddening, spectrophotometric distance, mass, radius, luminosity, and age). The comparison between spectrophotometric and parallax-based distances enables us to disentangle the MS candidates from older blue horizontal branch (BHB) candidates. We identify 12 runaway MS candidates, with masses between 2 and 6 Msun. Their trajectories are traced back to the Galactic disc to identify their most recent Galactic plane crossings and the corresponding flight times. All 12 candidates are ejected from the Galactic disc within 2 to 16.5 kpc from the Galactic center and possess flight times that are shorter than their evolutionary ages, compatible with a runaway hypothesis. Three MS candidates have ejection velocities exceeding 450 km/s, thus, appear to challenge the canonical ejection scenarios for late B-type stars. The fastest star of our sample also has a non-negligible Galactic escape probability if its MS nature can be confirmed. We identify 27 BHB candidates, and the two hottest stars in our sample are rare late O and early B type stars of low mass evolving towards the white dwarf cooling sequence.Comment: Accepted for publication in A&A; abbreviated abstract; 16 pages, 13 figures, 5 table

Diseño de un programa de mantenimiento productivo total TPM para vehículos livianos en general del taller mecánico automotriz Tecnicamp

Definir la situación actual del taller “Tecnicamp” en relación a los tiempos, movimientos, actividades y cumplimiento con respecto a los servicios de mantenimiento que presta, así elaborar el plan de mantenimiento independiente como base para la aplicación del tpm mediante la propuesta de implementación de los pilares del tpm y el sistema de las 5s

Perfil clínico y radiológico en pacientes con diagnóstico de neumonía entre las edades de 3 meses a 5 años que consultaron en Unidad de Emergencia de HNNBB de Enero a Diciembre 2016.

Neumonía es la inflamación del parénquima pulmonar mejor caracterizada por sintomatología respiratoria, con presencia de fiebre, escalofríos, tos y expectoración. Para algunos investigadores, la prueba diagnóstica considerada como 'gold standard' actual lo constituye la radiografía convencional de tórax, pues posee una alta especificidad así como alta sensibilidad, por otro lado ciertos investigadores han evidenciado que los hallazgos radiológicos no pueden determinar etiología y por lo tanto no pueden orientar manejo. Estudios reportan que en los pacientes en que se solicitó una radiografía de tórax por sospecha de neumonía se produjeron cambios en el diagnóstico hasta en un 20% de los casos y en el manejo hasta en un 30% de los casos. El presente trabajo de investigación describe el perfil clínico y radiológico en niños con diagnóstico de neumonía entre las edades de 3 meses a 5 años, que consultaron en unidad de emergencia de HNNBB de enero a diciembre del 2016, se evaluaron patrones radiológicos encontrados y abordaje

Vitamin D receptor gene polymorphisms and prognosis of breast cancer among African-American and Hispanic women.

BackgroundVitamin D plays a role in cancer development and acts through the vitamin D receptor (VDR). Although African-Americans have the lowest levels of serum vitamin D, there is a dearth of information on VDR gene polymorphisms and breast cancer among African-Americans and Hispanics. This study examines whether VDR gene polymorphisms are associated with breast cancer in these cohorts.MethodsBlood was collected from 232 breast cancer patients (Cases) and 349 non-cancer subjects (Controls). Genotyping for four polymorphic variants of VDR (FokI, BsmI, TaqI and ApaI) was performed using the PCR-RFLP method.ResultsAn increased association of the VDR-Fok1 f allele with breast cancer was observed in African-Americans (OR = 1.9, p = 0.07). Furthermore, the FbTA, FbtA and fbtA haplotypes were associated with breast cancer among African-Americans (p&lt;0.05). Latinas were more likely to have the VDR-ApaI alleles (Aa or aa) (p = 0.008). The VDR-ApaI aa genotype was significantly associated with poorly-differentiated breast tumors (p = 0.04) in combined Cases. Kaplan-Meier survival analysis showed decreased 5-year disease-free-survival (DFS) in breast cancer patients who had the VDR-Fok1 FF genotype (p&lt;0.05). The Cox regression with multivariate analysis revealed the independent predictor value of the VDR-FokI polymorphism for DFS. The other three variants of VDR (BsmI, TaqI and ApaI) were not associated with disease outcome.ConclusionsVDR haplotypes are associated with breast cancer in African-Americans, but not in Hispanic/Latinas. The VDR-FokI FF genotype is linked with poor prognosis in African-American women with breast cancer