Covariance Estimation from Compressive Data Partitions using a Projected Gradient-based Algorithm

Covariance matrix estimation techniques require high acquisition costs that challenge the sampling systems' storing and transmission capabilities. For this reason, various acquisition approaches have been developed to simultaneously sense and compress the relevant information of the signal using random projections. However, estimating the covariance matrix from the random projections is an ill-posed problem that requires further information about the data, such as sparsity, low rank, or stationary behavior. Furthermore, this approach fails using high compression ratios. Therefore, this paper proposes an algorithm based on the projected gradient method to recover a low-rank or Toeplitz approximation of the covariance matrix. The proposed algorithm divides the data into subsets projected onto different subspaces, assuming that each subset contains an approximation of the signal statistics, improving the inverse problem's condition. The error induced by this assumption is analytically derived along with the convergence guarantees of the proposed method. Extensive simulations show that the proposed algorithm can effectively recover the covariance matrix of hyperspectral images with high compression ratios (8-15% approx) in noisy scenarios. Additionally, simulations and theoretical results show that filtering the gradient reduces the estimator's error recovering up to twice the number of eigenvectors.Comment: submitted to IEEE Transactions on Image Processin

Sexual and Reproductive Health for Young Adults in Colombia: Teleconsultation Using Mobile Devices

Background: Sexual risk behaviors associated with poor information on sexuality have contributed to major public health problems in the area of sexual and reproductive health in teenagers and young adults in Colombia. Objective: To report our experience with the use of DoctorChat Mobile to provide sexual education and information among university students in Bogota, Colombia, and knowledge about the sexual risk factors detected among them. Methods: A mobile app that allows patients to ask about sexual and reproductive health issues was developed. Sexual and reproductive risk behaviors in a sample of young adults were measured before and after the use of the app through the validated survey Family Health International (FHI) Behavioral Surveillance Survey (BSS) for Use With Adults Between 15 and 49 Years. A nonprobabilistic convenience recruitment was undertaken through the study´s webpage. After completing the first survey, participants were allowed to download and use the app for a 6-month period (intervention), followed by completion of the same survey once again. For the inferential analysis, data was divided into 3 groups (dichotomous data, discrete quantitative data, and ordinal data) to compare the results of the questions between the first and the second survey. The study was carried out with a sample of university students between 18 and 29 years with access to mobile phones. Participation in the study was voluntary and anonymous. Results: A total of 257 subjects met the selection criteria. The preintervention survey was answered by 232 subjects, and 127 of them fully answered the postintervention survey. In total, 54.3% (69/127) of the subjects completed the survey but did not use the app, leaving an effective population of 58 subjects for analysis. Of these subjects, 53% (31/58) were women and 47% (27/58) were men. The mean age was 21 years, ranging between 18 and 29 years. The differences between the answers from both surveys were not statistically significant. The main sexual risk behaviors identified in the population were homosexual intercourse, nonuse of condoms, sexual intercourse with nonregular and commercial partners, the use of psychoactive substances, and lack of knowledge on symptoms of sexually transmitted diseases and HIV transmission. Conclusions: Although there were no differences between the pre- and postintervention results, the study revealed different risk behaviors among the participating subjects. These findings highlight the importance of promoting high-impact educational strategies on this matter and the importance of providing teenagers and young adults with easily accessible tools with reliable health information, regardless of their socioeconomic status

Resistencia antimicrobiana en cepas de Pseudomonas aeruginosa aisladas de aguas termales de la provincia del Chimborazo, Ecuador

Introducción. La  intervención humana en los manantiales de aguas termales ha traído su contaminación microbiológica y química. El uso indiscriminado de los antimicrobianos, han desembocado en la contaminación de diversos ambientes acuáticos con estas sustancias y con bacterias resistentes a las mismas. Objetivo. Conocer la resistencia antimicrobiana en cepas de Pseudomonas aeruginosa aisladas de aguas termales de la región del Chimborazo, Ecuador. Métodos. Se analizaron 12 muestras de agua termal procedentes de baños de la Provincia del Chimborazo. Las muestras consistieron de un volumen de 0,5 litro de agua  de cada manantial.  El aislamiento de Pseudomonas aeruginosa se realizó por la técnica de filtración en membrana, utilizando filtros de acetato de celulosa de 0,45 μm de poro, un volumen de muestra de 100 ml y el agar Cetrimide. Las cepas aisladas se identificaron siguiendo los esquemas de MacFadden (2004) y Barrow y Feltham (1993), complementados con las pruebas bioquímicas de las galerías APHI (Biomerieux). El perfil de resistencia a los antibióticos se determinó por el método de difusión de Kirby y Bauer (1966) interpretándose según el CLSI (2014). Resultados. Se identificaron 15 cepas de Pseudomonas aeruginosa.  Todas las cepas fueron  resistentes a los antibióticos Ampicilina y Ampicilina-Sulbactam, y siete fueron multiresistentes a cinco antibióticos  (Ampicilina, Ampicilina-Sulbactam, Amikacina, Ceftazidime, Cefepime y Ciprofloxacina). Conclusiones. Los resultados  nos señalan la necesidad de realizar estudios del resistoma de los ecosistemas de las aguas termales, para determinar la presencia de genes de resistencias en las bacterias autóctonas

Evaluation of different bowel preparations for small bowel capsule endoscopy: a prospective, randomized, controlled study

To obtain an adequate view of the whole small intestine during capsule endoscopy (CE) a clear liquid diet and overnight fasting is recommended. However, intestinal content can hamper vision in spite of these measures. Our aim was to evaluate tolerance and degree of intestinal cleanliness during CE following three types of bowel preparation. PATIENTS AND METHODS: This was a prospective, multicenter, randomized, controlled study. Two-hundred ninety-one patients underwent one of the following preparations: 4 L of clear liquids (CL) (group A; 92 patients); 90 mL of aqueous sodium phosphate (group B; 89 patients); or 4 L of a polyethylene glycol electrolyte solution (group C; 92 patients). The degree of cleanliness of the small bowel was classified by blinded examiners according to four categories (excellent, good, fair or poor). The degree of patient satisfaction, gastric and small bowel transit times, and diagnostic yield were measured. RESULTS: The degree of cleanliness did not differ significantly between the groups (P = 0.496). Interobserver concordance was fair (k = 0.38). No significant differences were detected between the diagnostic yields of the CE (P = 0.601). Gastric transit time was 35.7 +/- 3.7 min (group A), 46.1 +/- 8.6 min (group B) and 34.6 +/- 5.0 min (group C) (P = 0.417). Small-intestinal transit time was 276.9 +/- 10.7 min (group A), 249.7 +/- 13.1 min (group B) and 245.6 +/- 11.6 min (group C) (P = 0.120). CL was the best tolerated preparation. Compliance with the bowel preparation regimen was lowest in group C (P = 0.008). CONCLUSIONS: A clear liquid diet and overnight fasting is sufficient to achieve an adequate level of cleanliness and is better tolerated by patients than other forms of preparation

Overexpression of cathepsin f, matrix metalloproteinases 11 and 12 in cervical cancer

BACKGROUND: Cervical carcinoma (CC) is one of the most common cancers among women worldwide and the first cause of death among the Mexican female population. CC progression shows a continuum of neoplastic transitions until invasion. Matrix metalloproteinases (MMPs) and cathepsins play a central role on the enhancement of tumor-induced angiogenesis, cell migration, proliferation, apoptosis and connective tissue degradation. MMPs -2 and -9 expression has been widely studied in cervical cancer. Nevertheless, no other metalloproteinases or cathepsins have been yet related with the progression and/or invasion of this type of cancer. METHODS: Three HPV18 CC cell lines, two HPV16 CC cell lines and three HPV16 tumor CC tissues were compared with three morphologically normal, HPV negative, cervical specimens by cDNA arrays. Overexpression of selected genes was confirmed by end point semiquantitative reverse transcription-PCR with densitometry. In situ hybridization and protein expression of selected genes was further studied by means of two tissue microarrays, one consisting of 10 HSIL and 15 CC and the other one of 15 normal cervical and 10 LSIL tissues. RESULTS: TIMP1, Integrins alpha 1 and 4, cadherin 2 and 11, Cathepsins F, B L2, MMP 9, 10 11 and 12 were upregulated and Cathepsin S, L, H and C, Cadherins 3 and 4, TIMP3, MMP 13, Elastase 2 and Integrin beta 8 were found to be downregulated by cDNA arrays. Endpoint RT-PCR with densitometry gave consistent results with the cDNA array findings for all three genes selected for study (CTSF, MMP11 and MMP12). In situ hybridization of all three genes confirmed overexpression in all the HSIL and CC. Two of the selected proteins were detected in LSIL, HSIL and CC by immunohistochemistry. CONCLUSION: Novel undetected CC promoting genes have been identified. Increased transcription of these genes may result in overexpression of proteins, such as CTSF, MMP11 and MMP12 which could contribute to the pathogenesis of CC

Immunogenic Profiling in Mice of a HIV/AIDS Vaccine Candidate (MVA-B) Expressing Four HIV-1 Antigens and Potentiation by Specific Gene Deletions

BACKGROUND: The immune parameters of HIV/AIDS vaccine candidates that might be relevant in protection against HIV-1 infection are still undefined. The highly attenuated poxvirus strain MVA is one of the most promising vectors to be use as HIV-1 vaccine. We have previously described a recombinant MVA expressing HIV-1 Env, Gag, Pol and Nef antigens from clade B (referred as MVA-B), that induced HIV-1-specific immune responses in different animal models and gene signatures in human dendritic cells (DCs) with immunoregulatory function. METHODOLOGY/PRINCIPAL FINDINGS: In an effort to characterize in more detail the immunogenic profile of MVA-B and to improve its immunogenicity we have generated a new vector lacking two genes (A41L and B16R), known to counteract host immune responses by blocking the action of CC-chemokines and of interleukin 1beta, respectively (referred as MVA-B DeltaA41L/DeltaB16R). A DNA prime/MVA boost immunization protocol was used to compare the adaptive and memory HIV-1 specific immune responses induced in mice by the parental MVA-B and by the double deletion mutant MVA-B DeltaA41L/DeltaB16R. Flow cytometry analysis revealed that both vectors triggered HIV-1-specific CD4(+) and CD8(+) T cells, with the CD8(+) T-cell compartment responsible for >91.9% of the total HIV-1 responses in both immunization groups. However, MVA-B DeltaA41L/DeltaB16R enhanced the magnitude and polyfunctionality of the HIV-1-specific CD4(+) and CD8(+) T-cell immune responses. HIV-1-specific CD4(+) T-cell responses were polyfunctional and preferentially Env-specific in both immunization groups. Significantly, while MVA-B induced preferentially Env-specific CD8(+) T-cell responses, MVA-B DeltaA41L/DeltaB16R induced more GPN-specific CD8(+) T-cell responses, with an enhanced polyfunctional pattern. Both vectors were capable of producing similar levels of antibodies against Env. CONCLUSIONS/SIGNIFICANCE: These findings revealed that MVA-B and MVA-B DeltaA41L/DeltaB16R induced in mice robust, polyfunctional and durable T-cell responses to HIV-1 antigens, but the double deletion mutant showed enhanced magnitude and quality of HIV-1 adaptive and memory responses. Our observations are relevant in the immune evaluation of MVA-B and on improvements of MVA vectors as HIV-1 vaccines

Propuesta metodológica para potencializar las capacidades perceptivo-motrices más preponderantes en el estilo upperbody en la práctica deportiva Freestyle football en sujetos de 13 a 17 años

La siguiente investigación plantea una propuesta metodológica para el entrenamiento adecuado de las capacidades perceptivo motrices implícitas en el estilo upperbody de la práctica deportiva Freestyle Football en la etapa de 13 a 17 años

Propuesta metodológica para potencializar las capacidades perceptivo-motrices más preponderantes en el estilo upperbody en la práctica deportiva Freestyle football en sujetos de 13 a 17 años

La siguiente investigación plantea una propuesta metodológica para el entrenamiento adecuado de las capacidades perceptivo motrices implícitas en el estilo upperbody de la práctica deportiva Freestyle Football en la etapa de 13 a 17 años