A Cognitive Apprenticeship Approach for Teaching Abstract and Complex Skills in an Online Learning Environment

Undergraduate courses such as mathematics, science, and computer programming require high levels of decision making, concentration, and cognitive demand. Researchers in the field of instructional design are interested in effective instructional strategies that can aid practitioners in teaching such abstract and complex skills. One example of an instructional strategy that has proven effective in teaching these skills is cognitive apprenticeship (CA). While CA has been applied to courses such as mathematics and computer programming in face-to-face and blended learning environments, there is little evidence of the advantages of applying CA in a fully online computer programming course. Specifically, the introductory programming course, CS1, is the first contact that undergraduate computer science students have with their chosen major. Historically, drop-out rates for CS1 have been high and thus strategies for effective teaching of this course have served as an important topic in the research literature. The goal was to design and validate internally an online CS1 course that incorporates CA strategies. A two-phase design and development research method was used to guide the construction and internal validation of a fully online CS1 course. Phase one resulted in the design and development of the course guide. An expert-review process using the Delphi technique was implemented in phase two to validate the design with regard to its effectiveness, efficiency, and appeal. Three rounds of review by the panel resulted in consensus. Results from the expert-review confirmed the application of CA as an effective, efficient, and appealing instructional strategy to use when designing an online CS1 course. Future research should focus on external validation of the design by implementing the course to evaluate its effectiveness, efficiency, and appeal among stakeholders. In addition, it is hoped that the course guide can be used to help practitioners design and implement a fully online CS1 course that uses CA strategies

Bacterial outer membrane vesicles and vaccine applications

Vaccines based on outer membrane vesicles (OMV) were developed more than 20 years ago against Neisseria meningitidis serogroup B. These nano-sized structures exhibit remarkable potential for immunomodulation of immune responses and delivery of “self” meningococcal antigens or unrelated antigens incorporated into the vesicle structure. This paper reviews different applications in OMV Research and Development (R&D) and provides examples of OMV developed and evaluated at the Finlay Institute in Cuba. A Good Manufacturing Practice (GMP) process was developed at the Finlay Institute to produce OMV from N. meningitidis serogroup B (dOMVB) using detergent extraction. Subsequently, OMV from N. meningitidis, serogroup A (dOMVA), serogroup W (dOMVW) and serogroup X (dOMVX) were obtained using this process. More recently, the extraction process has also been applied effectively for obtaining OMV on a research scale from Vibrio cholerae (dOMVC), Bordetella pertussis (dOMVBP), Mycobacterium smegmatis (dOMVSM) and BCG (dOMVBCG). The immunogenicity of the OMV have been evaluated for specific antibody induction, and together with functional bactericidal and challenge assays in mice have shown their protective potential. dOMVB has been evaluated with non-self neisserial antigens, including with a herpes virus type 2 glycoprotein, ovalbumin and allergens. In conclusion, OMV are proving to be more versatile than first conceived and remain an important technology for development of vaccine candidates. - See more at: http://journal.frontiersin.org/Journal/10.3389/fimmu.2014.00121/abstract#sthash.MwqUyZQ1.dpu

Prevalence and mapping of hepatitis C infections among men who have sex with men in New York City

Emerging sexually transmitted hepatitis C virus (HCV) epidemics among men who have sex with men (MSM) have been reported worldwide, with higher HCV infection rates among those who are HIV-infected. This study aims to determine prevalence of recent and chronic HCV infections among community-recruited MSM in New York City (NYC), map HCV infections by home, social, and sexual neighborhoods, and identify clusters of genetically linked HCV variants using phylogenetic analysis. The NYC M2M study recruited MSM via modified time-space, venue-based sampling and internet/mobile app-based recruitment during 2010–13. Participants completed a Google Earth map on neighborhoods of where they lived, socialized, and had sex in the last 3 months, an ACASI questionnaire, and a sexual network inventory about their sex partners. The men received HIV testing and provided serum samples. Testing on stored serum samples included HCV antibody and RNA viral load, HCV antibody avidity assay (avidity index 40 years, adjusted odds ratio (aOR) 3.56 (95% CI 1.57, 8.08), HIV-positive serostatus, aOR 3.18 (95% CI 1.40, 7.22), any sexually transmitted infection (STI) in the last 3 months, aOR 2.81 (95% CI 1.11, 7.13), and injection drug use (IDU) ever, aOR 4.34 (95% CI 1.69, 11.17). Mapping of HCV infections differed slightly by home, social, and sexual neighborhoods. Based on phylogenetic analysis from 12 HCV RNA-positive samples, no evidence of a clustered HCV epidemic was found. Overall HCV seroprevalence was 2.8% among community-recruited MSM in NYC, with higher prevalence among HIV-positive MSM compared to HIV-negative MSM. Only two participants were found to have recent HCV infection, with no evidence of a clustered HCV epidemic based on phylogenetic analysis. Our results support testing of HCV infection among HIV-negative MSM if they report having a recent STI and IDU in the past rather than universal HCV testing in all HIV-negative MSM

Prevalence and mapping of hepatitis C infections among men who have sex with men in New York City

Emerging sexually transmitted hepatitis C virus (HCV) epidemics among men who have sex with men (MSM) have been reported worldwide, with higher HCV infection rates among those who are HIV-infected. This study aims to determine prevalence of recent and chronic HCV infections among community-recruited MSM in New York City (NYC), map HCV infections by home, social, and sexual neighborhoods, and identify clusters of genetically linked HCV variants using phylogenetic analysis. The NYC M2M study recruited MSM via modified time-space, venue-based sampling and internet/mobile app-based recruitment during 2010–13. Participants completed a Google Earth map on neighborhoods of where they lived, socialized, and had sex in the last 3 months, an ACASI questionnaire, and a sexual network inventory about their sex partners. The men received HIV testing and provided serum samples. Testing on stored serum samples included HCV antibody and RNA viral load, HCV antibody avidity assay (avidity index 40 years, adjusted odds ratio (aOR) 3.56 (95% CI 1.57, 8.08), HIV-positive serostatus, aOR 3.18 (95% CI 1.40, 7.22), any sexually transmitted infection (STI) in the last 3 months, aOR 2.81 (95% CI 1.11, 7.13), and injection drug use (IDU) ever, aOR 4.34 (95% CI 1.69, 11.17). Mapping of HCV infections differed slightly by home, social, and sexual neighborhoods. Based on phylogenetic analysis from 12 HCV RNA-positive samples, no evidence of a clustered HCV epidemic was found. Overall HCV seroprevalence was 2.8% among community-recruited MSM in NYC, with higher prevalence among HIV-positive MSM compared to HIV-negative MSM. Only two participants were found to have recent HCV infection, with no evidence of a clustered HCV epidemic based on phylogenetic analysis. Our results support testing of HCV infection among HIV-negative MSM if they report having a recent STI and IDU in the past rather than universal HCV testing in all HIV-negative MSM

Obtención de una película a base de almidón hidroxipropilado producida por extrusión soplado

El problema de la difícil degradación de los plásticos convencionales y su acumulación en el medio ambiente, ha conducido a investigadores a buscar materiales alternos, en el presente trabajo se buscó la obtención de películas elaboradas a base de almidón de yuca hidroxipropilado de la variedad CM 7137, el cual fue sometido a un proceso de plastificación con glicerina para posteriormente unirse con una mezcla binaria de ácido poliláctico (PLA) y policaprolactona (PCL) para obtener la película o mezcla ternaria de TPS, PLA y PCL a través de la técnica de extrusión. Para determinar las condiciones óptimas para la obtención de las películas se empleó un diseño experimental factorial 23, con 3 réplicas. Los resultados obtenidos se sometieron a la metodología de superficie de respuesta donde las variables de entrada fueron perfil de temperatura de la extrusión soplado, porcentaje de capsaicina y porcentaje de mezcla binaria, la variable de respuesta fue la elongación, en porcentaje. Las condiciones óptimas encontradas fueron 25% de mezcla binaria, perfil de temperatura de 140/145/155/150°C, y 0,5% de capsaicina, la cual de manera preliminar mostró un efecto antimicrobiano. Se observó que el material obtenido presentó mejores propiedades que las encontradas para películas a base de almidón nativo.

Evaluación de propiedades mecánicas, ópticas y de barrera en películas activas de almidón de yuca

Películas obtenidas a partir de almidón de yuca de la variedad CM 7138 -7, nativo y modificado por hidroxipropilación, fueron sometidas a evaluaciones mecánicas, ópticas y de barrera, durante periodos de tiempo de 0, 30, 60, 90 y 120 días determinando el efecto del tiempo de almacenamiento  sobre la modificación química realizada. Las películas fueron obtenidas por extrusión soplado por medio de un extrusor de tornillo simple. El material se obtuvo en tres etapas: la primera etapa fue la producción de Almidón Termoplástico (TPS) con 75% de almidón, 24,5% de glicerol y 0,5% de capsaicina; en la segunda etapa, se realizó la Mezcla Binaria (MB) con 68,63% de Ácido Poliláctico (PLA), 29,41% de Policaprolactona (PCL), 1,96% de anhídrido maleico y 1% de colorante y, por último se realizó la extrusión soplado de la mezcla ternaria, compuesta por 75% de TPS y 25% MB. Los cambios de algunas propiedades con respecto al tiempo, fueron más evidentes en las películas a base de almidón nativo presentando una diferencia significativa, debido al proceso de retrogradación y posiblemente a que no se formó una fase homogénea en el material y por lo tanto los componentes se distribuyeron en fases distintas y separadas. 

Homogeneizacion reiterada de un problema de contorno unidimensional

The asymptotic homogenization method is applied to homogenize a one-dimensional family of elliptic boundary value problems with periodic and rapidly oscillating coefficients which depend on two fast variables. The homogenized problem, the local problems and the corresponding effective coefficient are obtained. A necessary and sufficient condition for constructing an asymptotic solution with periodic terms is demonstrated. Based on a Maximum Principle the proximity between the solutions of the homogenized and original problems is proved. Some numerical computations are used to illustrate the mathematical justificationEl metodo de homogeneizacion asintotica es aplicado para homogeneizar una familia unidimensional de problemas elıpticos, con coeficientes periodicos y rapidamente oscilantes que dependen de dos variables rapidas. El problema homogeneizado, los problemas locales y los correspondientes coeficientes efectivos son obtenidos. Una condicion necesaria y suficiente para la construccion de una solucion asintotica con terminos periodicos es demostrada. Basados en el principio del maximo, se demuestra la proximidad entre la soluci´on del problema homogeneizado y la del problema original. Se propone un ejemplo numerico para ilustrar la justificacion matematica

Effect of refrigeration on post-harvest flowers

Cut flowers have a very limited life after they have been cut off from the mother plant, as survival on their own reserves is generally low due to the special morphological and physiological characteristics of their tissues. The use of refrigeration for storage of flower cuttings is very important because it reduces water loss, senescence, infections caused by bacteria and fungi, thus extending the shelf-life of flowers during the storage period. Therefore, the aim of the present work is to show differences between requirements of various species of flowers during refrigerated storage.Keywords: Cooling, post-harvest, conservation, flowers, cold injur

COVID-19 Convalescent Plasma Therapy Decreases Inflammatory Cytokines: A Randomized Controlled Trial

This study examined the role that cytokines may have played in the beneficial outcomes found when outpatient individuals infected with SARS-CoV-2 were transfused with COVID-19 convalescent plasma (CCP) early in their infection. We found that the pro-inflammatory cytokine IL-6 decreased significantly faster in patients treated early with CCP. Participants with COVID-19 treated with CCP later in the infection did not have the same effect. This decrease in IL-6 levels after early CCP treatment suggests a possible role of inflammation in COVID-19 progression. The evidence of IL-6 involvement brings insight into the possible mechanisms involved in CCP treatment mitigating SARS-CoV-2 severity

Dynamics of Inflammatory Responses After SARS-CoV-2 Infection by Vaccination Status in the USA: A Prospective Cohort Study

BACKGROUND: Cytokines and chemokines play a critical role in the response to infection and vaccination. We aimed to assess the longitudinal association of COVID-19 vaccination with cytokine and chemokine concentrations and trajectories among people with SARS-CoV-2 infection. METHODS: In this longitudinal, prospective cohort study, blood samples were used from participants enrolled in a multi-centre randomised trial assessing the efficacy of convalescent plasma therapy for ambulatory COVID-19. The trial was conducted in 23 outpatient sites in the USA. In this study, participants (aged ≥18 years) were restricted to those with COVID-19 before vaccination or with breakthrough infections who had blood samples and symptom data collected at screening (pre-transfusion), day 14, and day 90 visits. Associations between COVID-19 vaccination status and concentrations of 21 cytokines and chemokines (measured using multiplexed sandwich immunoassays) were examined using multivariate linear mixed-effects regression models, adjusted for age, sex, BMI, hypertension, diabetes, trial group, and COVID-19 waves (pre-alpha or alpha and delta). FINDINGS: Between June 29, 2020, and Sept 30, 2021, 882 participants recently infected with SARS-CoV-2 were enrolled, of whom 506 (57%) were female and 376 (43%) were male. 688 (78%) of 882 participants were unvaccinated, 55 (6%) were partly vaccinated, and 139 (16%) were fully vaccinated at baseline. After adjusting for confounders, geometric mean concentrations of interleukin (IL)-2RA, IL-7, IL-8, IL-15, IL-29 (interferon-λ), inducible protein-10, monocyte chemoattractant protein-1, and tumour necrosis factor-α were significantly lower among the fully vaccinated group than in the unvaccinated group at screening. On day 90, fully vaccinated participants had approximately 20% lower geometric mean concentrations of IL-7, IL-8, and vascular endothelial growth factor-A than unvaccinated participants. Cytokine and chemokine concentrations decreased over time in the fully and partly vaccinated groups and unvaccinated group. Log INTERPRETATION: Initially and during recovery from symptomatic COVID-19, fully vaccinated participants had lower concentrations of inflammatory markers than unvaccinated participants suggesting vaccination is associated with short-term and long-term reduction in inflammation, which could in part explain the reduced disease severity and mortality in vaccinated individuals. FUNDING: US Department of Defense, National Institutes of Health, Bloomberg Philanthropies, State of Maryland, Mental Wellness Foundation, Moriah Fund, Octapharma, HealthNetwork Foundation, and the Shear Family Foundation