Quantitative methods to determine the student workload: II. Statistical models for the microcurricular performance indicators.

Previously, we observed that the student workload follows an inverse relation with the learning rate (an application of the kinematic notion of speed contextualized to the learning process). Motivated by this finding, we propose a quantitative estimation of the learning rate using a different source of information: the historical records of final grades of a given course. According to empirical data analyzed in other similar studies, the distribution functions of final grades exhibit a regular pattern: a Gaussian behavior for the approval region and a homogeneous distribution for the failed one. This fact is combined with the incidence of student elimination-desertion rules for introducing two simple agent-based models. Our analysis is complemented by revisiting the performance indicators typically employed to characterize the student promotion and progression. We discuss some other performance indicators to characterize the learning advancement of students: the group learning rate and the learning curve. We compare the results of Monte Carlo simulations with empirical data, observing a good agreement in the behavior of performance indicators derived from these sources. This analysis suggests an adaptive method for the readjustment of the student workload (the number of academic credits) considering the group learning rates during a follow-up period, which resembles the readjustment of prices of goods (and services) in correspondence with the evolution of supply and demand.

Quantitative methods to determine the student workload. I. Empirical study based on digital platforms.

We present a quantitative study of an online course developed during COVID19 sanitary emergency in Chile. We reconstruct the teaching-learning process considering the activity logs on digital platforms in order to answer the question of How do our students study? The results from the analysis evidence the complex adaptive character of the academic environment, which exhibits regularities similar to those found in financial markets (e.g., distributions of the daily time devoted to learning activities follow patterns like Pareto's or Zipf's law). Our empirical results illustrate (i) the relevance of economic notions in the understanding of the teaching-learning processes and (ii) the reliability of quantitative methods based on digital platforms to conduct experimental studies in this framework. We introduce in the present work a series of indicators to characterize the performance of professors, students' follow-up of the course, and their learning progress by crossing information with the results of assessments. In this context, the learning rate appears as a key statistical descriptor for the allocation of the student workload.

Preparation and in vitro evaluation of PLA/biphasic calcium phosphate filaments used for fused deposition modelling of scaffolds.

Ceramic materials such as calcium phosphates (CaPs) with a composition similar to the mineral phase of bones and polymeric polylactic acid (PLA) are potential candidates for the manufacturing of scaffolds to act as bone substitutes and for tissue engineering applications, due to their bioresorbability and biocompatibility. Variables such as porosity, topography, morphology, and mechanical properties play an essential role in the scaffolds response. In this paper, a polymer/ceramic composite filament of 1.7 mm in diameter based on PLA and biphasic calcium phosphates (BCPs) was obtained by hot-melt extrusion in a single screw extruder. The particles of BCP were obtained by solution-combustion synthesis, and the PLA used was commercial grade. The BCPs ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopy (TEM), and Brunauer, Emmett, and Teller (BET). It was possible to confirm that the main inorganic phases were hydroxyapatite (HAP) and tricalcium phosphate (TCP) with grain sizes below 100 nm and with high porosity. The Filaments obtained are a bit fragile but were able to be used in fused deposition modelling (FDM) using low-cost commercial printers. The filaments were characterized by SEM and energy dispersive X-ray (EDX). The in-vitro tests of filaments showed deposition of apatite phases on their surface, non-cytotoxic behavior, adequate cell proliferation and cell adhesion.

Fluctuations in measured radioactive decay rates inside a modified Faraday cage: Correlations with space weather.

For several years, reports have been published about fluctuations in measured radioactive decay time-series and in some instances linked to astrophysical as well as classical environmental influences. Anomalous behaviors of radioactive decay measurement and measurement of capacitance inside and outside a modified Faraday cage were documented by our group in previous work. In the present report, we present an in-depth analysis of our measurement with regard to possible correlations with space weather, i.e. the geomagnetic activity (GMA) and cosmic-ray activity (CRA). Our analysis revealed that the decay and capacitance time-series are statistically significantly correlated with GMA and CRA when specific conditions are met. The conditions are explained in detail and an outlook is given on how to further investigate this important finding. Our discovery is relevant for all researchers investigating radioactive decay measurements since they point out that the space weather condition during the measurement is relevant for partially explaining the observed variability.

Peculiarities of the obese patient with cancer: a national consensus statement by the Spanish Society for the Study of Obesity and the Spanish Society of Medical Oncology.

The relationship between obesity and cancer is clear and is present at all times during course of the disease. The importance of obesity in increasing the risk of developing cancer is well known, and some of the most prevalent tumours (breast, colorectal, and prostate) are directly related to this risk increase. However, there is less information available on the role that obesity plays when the patient has already been diagnosed with cancer. Certain data demonstrate that in some types of cancer, obese patients tolerate the treatments more poorly. Obesity is also known to have an impact on the prognosis, favouring lower survival rates or the appearance of secondary tumours. In this consensus statement, we will analyse the scientific evidence on the role that obesity plays in patients already diagnosed with cancer, and the available data on how obesity control can improve the quality of daily life for the cancer patient.

Entornos virtuales en la enseñanza superior de enfermería. Nuestra Experiencia / Blended learning in postgraduate education for nurses. Our experience

El objetivo de este estudio fue implementar los entornos virtuales (blended learning) en la enseñanza superior de enfermería y describir la adherencia de los alumnos de la cátedra de administración en enfermería a las nuevas estrategias didácticas. Material y Método: trabajo retrospectivo, descriptivo y observacional. Se reviso la base del Centro de innovación tecnología y pedagogía de la UBA (CITEP) de 210 alumnos inscriptos en la cátedra de administración en enfermería distribuidos en 3 comisiones desde marzo a diciembre del 2015. Se describieron los datos sociodemográficos, las experiencias previas en entornos virtuales, articulación de los contenidos (áulicos con los virtuales) y la Organización de la enseñanza. Resultados: La población estudiada 210 usuarios estuvo representada por sexo femenino 80% y 20% masculino. La Edad media fue de 28 años con un rango entre 20-48 años, la edad no constituyó una variable asociada a la no adherencia de los entornos virtuales en un 96% de los usuarios. El 55% n: 114 de los alumnos manifestó trabajar, el trabajo asociado a ámbitos de la salud estuvo presente en un 21% y el 33% manifestó trabajar en ámbitos fuera de la salud. El 63% de los usuarios tuvo alguna experiencia previa con los entornos virtuales durante el desarrollo de la carrera de Enfermería. El 86% de la población en estudio N:(180) refirió que la articulación de los contenidos áulicos con los virtuales les resulto practico N: (136) y muy práctico N: (44). El 90% N: (189) de los usuarios refirió que los contenido ofrecidos por los docentes en la plataforma virtual fueron útiles y muy útiles. El 63% N: (132) de la población incorporó el uso de la plataforma blended learning como herramienta pedagógica para el desarrollo del proceso enseñanza aprendizaje. El 83% de los alumnos recomendaron el espacio virtual a sus compañeros. Se observa el beneficio de las Estrategias didácticas innovadoras en la enseñanza superior de enfermería a través de los espacios virtuales blended learning (AU)

The aim of this study was to develop an online learning environment (blended learning) in postgraduate education for nurses and to describe adherence to the new teaching strategies of the pupils of the course of management in nursing. Materials and Methods: A retrospective, descriptive, observational study was conducted. The data base of the Center for Innovative Technology and Educational Sciences of the University of Buenos Aires (CITEP) of 210 pupils enrolled in the course of management in nursing distributed over 3 classes from March to December 2015 was reviewed. Sociodemographic data, previous experience with online education, content coordination (between face-to-face classroom practices and computer-mediated activities), and the organization of education were evaluated. Results: The study population consisted of 210 pupils of whom 80% were female and 20% male. Mean age was 28 years with a range from 20 to 48 years. The variable of age was not associated with nonadherence to the on-line education in 96% of the users. Overall, 55% N: 114 of the pupils reported to be currently working; 21% was working in health-care-related areas, and 33% was working in areas not related to health care. Of all users, 63% had some previous experience with on-line education during their nursing studies. Of the study population 86% N:(180) considered the content coordination between classroom practices and on-line activities practical N: (136) and very practical N: (44).Overall, 90% N: (189)of the users reported the contents offered by the teachers in the on-line platform to be useful and very useful; 63% N: (132) of the population incorporated the blended learning platform as an educational tool for the development of the learning process. Of all pupils, 83% recommended the on-line education to their colleagues. A clear benefit of the innovating teaching strategies in post-graduate courses in nursing through on-line blended learning was observed (AU)

Deformidad de pie en paciente diabético. Fractura-luxación de Lisfranc: a propósito de un caso / Foot deformity in a diabetic patient. Lisfranc fracture-dislocation: a case report

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Efficacy of Lysophosphatidylcholine in Combination with Antimicrobial Agents against Acinetobacter baumannii in Experimental Murine Peritoneal Sepsis and Pneumonia Models.

Immune response stimulation to prevent infection progression may be an adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC) is an immunomodulator involved in immune cell recruitment and activation. In this study, we aimed to evaluate the efficacy of LPC in combination with colistin, tigecycline, or imipenem in experimental murine models of peritoneal sepsis and pneumonia. We used Acinetobacter baumannii strain Ab9, which is susceptible to colistin, tigecycline, and imipenem, and multidrug-resistant strain Ab186, which is susceptible to colistin and resistant to tigecycline and imipenem. Pharmacokinetic and pharmacodynamic parameters for colistin, tigecycline, and imipenem and the 100% minimal lethal dose (MLD100) were determined for both strains. The therapeutic efficacies of LPC, colistin (60 mg/kg of body weight/day), tigecycline (10 mg/kg/day), and imipenem (180 mg/kg/day), alone or in combination, were assessed against Ab9 and Ab186 at the MLD100 in murine peritoneal sepsis and pneumonia models. The levels of pro- and anti-inflammatory cytokines, i.e., tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA) for the same experimental models after inoculating mice with the MLD of both strains. LPC in combination with colistin, tigecycline, or imipenem markedly enhanced the bacterial clearance of Ab9 and Ab186 from the spleen and lungs and reduced bacteremia and mouse mortality rates (P < 0.05) compared with those for colistin, tigecycline, and imipenem monotherapies. Moreover, at 4 h post-bacterial infection, Ab9 induced higher TNF-α and lower IL-10 levels than those with Ab186 (4 µg/ml versus 3 µg/ml [P < 0.05] and 2 µg/ml versus 3.4 µg/ml [P < 0.05], respectively). LPC treatment combined with colistin, tigecycline, or imipenem modestly reduced the severity of infection by A. baumannii strains with different resistance phenotypes compared to LPC monotherapy in both experimental models.

Linkage and association analysis of ADHD endophenotypes in extended and multigenerational pedigrees from a genetic isolate.

Attention-deficit/hyperactivity disorder (ADHD) is a heritable, chronic, neurodevelopmental disorder with serious long-term repercussions. Despite being one of the most common cognitive disorders, the clinical diagnosis of ADHD is based on subjective assessments of perceived behaviors. Endophenotypes (neurobiological markers that cosegregate and are associated with an illness) are thought to provide a more powerful and objective framework for revealing the underlying neurobiology than syndromic psychiatric classification. Here, we present the results of applying genetic linkage and association analyses to neuropsychological endophenotypes using microsatellite and single nucleotide polymorphisms. We found several new genetic regions linked and/or associated with these endophenotypes, and others previously associated to ADHD, for example, loci harbored in the LPHN3, FGF1, POLR2A, CHRNA4 and ANKFY1 genes. These findings, when compared with those linked and/or associated to ADHD, suggest that these endophenotypes lie on shared pathways. The genetic information provided by this study offers a novel and complementary method of assessing the genetic causes underpinning the susceptibility to behavioral conditions and may offer new insights on the neurobiology of the disorder.

Obesity as a risk factor in cancer: A national consensus of the Spanish Society for the Study of Obesity and the Spanish Society of Medical Oncology.

In the last few years, many prospective studies have demonstrated a clear association between obesity and cancers of the colon and rectum, breast in post-menopausal women, endometrium, kidney, oesophagus and pancreas. Obesity is also associated with a high risk of recurrence and cancer-related death. The pathophysiology of obesity involves various changes that may be implicated in the relationship between obesity and cancer, such as excess inflammatory cytokines and chronic inflammation, hyperinsulinaemia, insulin resistance, and raised leptin and oestrogens. The Spanish Society for the Study of Obesity and the Spanish Society of Medical Oncology have signed a cooperation agreement to work together towards reducing the impact of obesity in cancer. Preventing obesity prevents cancer.

Extended canonical Monte Carlo methods: Improving accuracy of microcanonical calculations using a reweighting technique.

Velazquez and Curilef [J. Stat. Mech. (2010); J. Stat. Mech. (2010)] have proposed a methodology to extend Monte Carlo algorithms that are based on canonical ensemble. According to our previous study, their proposal allows us to overcome slow sampling problems in systems that undergo any type of temperature-driven phase transition. After a comprehensive review about ideas and connections of this framework, we discuss the application of a reweighting technique to improve the accuracy of microcanonical calculations, specifically, the well-known multihistograms method of Ferrenberg and Swendsen [Phys. Rev. Lett. 63, 1195 (1989)]. As an example of application, we reconsider the study of the four-state Potts model on the square lattice L×L with periodic boundary conditions. This analysis allows us to detect the existence of a very small latent heat per site qL during the occurrence of temperature-driven phase transition of this model, whose size dependence seems to follow a power law qL(L)∝(1/L)z with exponent z≃0.26±0.02. Discussed is the compatibility of these results with the continuous character of temperature-driven phase transition when L→+∞.

Perfil biológico y social de la población trasplantada en el hospital Garrahan por hepatitis fulminante y su relación con la evolución postrasplante / Biological and social profile of patients who underwent liver transplantation because of acute liver failure at the Garrahan Hospital

El objetivo de este estudio fue describir el perfil biológico y social del paciente pediátrico con trasplante hepático por insuficiencia hepática aguda (IHA) y la evolución postrasplante. Material y Método: trabajo retrospectivo, descriptivo y observacional, se revisaron la base de datos de 142 pacientes trasplantados por IHA desde 1992 al 2008. Se describieron los datos demográficos y sociales, indicaciones de trasplante, tipo de injerto utilizado, compatibilidad del grupo ABO, evolución pos trasplante (resultados primarios), complicaciones del trasplante y sobrevida. Resultados: El 51% de los casos de IHA fue asociado a la hepatitis infecciosa por virus A (HAV) y el 41% correspondió a las IHA indeterminadas. El 85% de la población trasplantada (120 casos) recibió un donante de tipo cadavérico (DC) y la compatibilidad de grupo ABO fue del 85%. Las complicaciones más frecuentes fueron: biliares 33 casos, infecciones bacterianas 20 casos y vasculares 13 casos. El rechazo agudo estuvo presente en 72 casos mientras que el rechazo crónico se diagnosticó en 7 casos. La sobrevida de la IHA al año del postrasplante fue del 80% y a los 5 y 10 años fue del 77%. La conciencia de enfermedad reflejada en el cumplimiento de las consignas médicos sociales estuvo presente en un 86,25%. El 70% de los padres de los niños trasplantados eran biológicos y el 52% de la población provino del área centro (Buenos Aires, Córdoba, Entre Ríos, y Santa Fe). La cobertura estuvo a cargo del estado en el 45% de la muestra (AU)

The aim of this study was to describe the social and biological profile of pediatric patients who undergo liver transplantation because of acute liver failure (ALF) and post-transplant outcome. Material and Methods: A retrospective, descriptive, and observational study was conducted. The database of 142 patients who underwent liver transplantation because of ALF between 1992 and 2008 was reviewed. Demographic and social features, indication for transplantation, type of graft used, ABO group compatibility, post-transplant outcome (primary results), complications of the transplantation and survival were evaluated. Results: ALF was associated with infectious hepatitis A (HAV) in 51% of the cases and with indeterminate ALF in 41%. Overall, 85% of the transplanted patients (120 cases) received a deceased donor (DD) organ and ABO group compatibility was 85%. Most common complications were: biliary in 33 cases, bacterial infections in 20 cases, and vascular in 13 cases. Acute rejection was observed in 72 cases while chronic rejection was diagnosed in seven cases. Oneyear post-transplant survival after ALF was 80%, while 5- and 10-year survival was 77%. Disease awareness expressed in compliance with medical and social indications was observed in 86%. Seventy percent of the parents of transplanted children were there biological parents and 52% of the population came from the central area of the country (Buenos Aires, Córdoba, Entre Ríos, y Santa Fe). Forty-five percent of the sample had public health care coverage (AU)

The effect of orally administered probiotic Lactobacillus reuteri-containing tablets in peri-implant mucositis: a double-blind randomized controlled trial.

BACKGROUND AND OBJECTIVES: Probiotics create a biofilm and protect the oral tissues against the action of periodontal pathogenic bacteria. The aim of this study was to evaluate the effects of the oral probiotic Lactobacillus reuteri Prodentis upon the peri-implant health of edentulous patients with dental implants and peri-implant mucositis, establishing comparisons vs implants without peri-implant disease. MATERIAL AND METHODS: A double-blind, placebo-controlled, prospective cross-over study was made. The patients were all edentulous and were divided into two groups, (A) no peri-implant disease, and (B) peri-implant mucositis affecting one or more implants. Patients with peri-implantitis were excluded. The dosage was one tablet every 24 h over 30 d. All patients in both groups initially received the oral probiotic Lactobacillus reuteri Prodentis, followed by placebo. Patients started with probiotic treatment during 30 d, followed by a 6 mo washout period and the administration of placebo for the same period. The following parameters were studied: crevicular fluid volume, modified plaque index, probing depth, modified gingival index, and concentrations of interleukin 1ß, interleukin 6 and interleukin 8. RESULTS: A total of 77 implants were evaluated in 34 patients. Group A involved 22 patients with 54 implants without peri-implant alterations, and group B, 12 patients with mucositis affecting one or more implants (23 implants). After treatment with the probiotic, both the patients with mucositis and the patients without peri-implant disease showed improvements in the clinical parameters, with reductions in cytokine levels. In contrast, no such changes were observed with placebo. CONCLUSIONS: After treatment with the probiotic Lactobacillus reuteri in patients with implants presenting mucositis, the clinical parameters improved, and the cytokine levels decreased - in contraposition to the observations in the placebo group. Probiotic administration may be regarded as a good alternative for both the treatment of peri-implant mucositis and its prevention, as it also improved clinical parameters in the healthy individuals. Further studies involving larger patient series are needed regarding the effects of probiotics upon peri-implant health.

Comparison of haematopoietic stem cell engraftment through the retro-orbital venous sinus and the lateral vein: alternative routes for bone marrow transplantation in mice.

Bone marrow transplantation in mice is performed by intravenous administration of haematopoietic repopulating cells, usually via the lateral tail vein. This technique can be technically challenging to carry out and may cause distress to the mice. The retro-orbital sinus is a large area where there is a confluence of several vessels that provides an alternative route for intravenous access. Retro-orbital injection, although aesthetically unpleasant, can be performed rapidly without requiring mechanical restriction or heat-induced vasodilation. In addition, this technique can be easily learned by novice manipulators. This route of administration has been reported for use in bone marrow transplantation but there is no comparison of retro-orbital and tail vein injections reported for this specific purpose, although both routes have been compared for many other applications. Here, we provide for the first time a comprehensive comparison between tail vein and retro-orbital injections for two different bone marrow transplant scenarios in P3B and B6D2F1 mice. In both cases, no significant differences regarding donor engraftment were observed between mice transplanted using each of the techniques. Haematological counts and leukocyte subpopulation distribution were practically identical between both animal groups. Moreover, donor engraftment levels were less homogenous when cells were transplanted by tail vein injection, probably due to a higher risk of failure associated with this technique. All these data suggest that retro-orbital injection is a compelling alternative to conventional tail vein injection for bone marrow transplant in mice, providing similar and more homogenous haematopoietic reconstitution.

Hemorragia severa secundaria a fractura osteoporótica de la pelvis: a propósito de un caso / Severe haemorrhage secondary to an osteoporotic pelvic fracture: Presentation of a case

La fractura osteoporótica de pelvis del anciano por baja energía es un proceso muy frecuente. Habitualmente son fracturas estables, no suelen suponer un riesgo vital y, únicamente precisan de tratamiento conservador. La estructura ósea pélvica tiene relación de proximidad con importantes estructuras vasculares. La Corona Mortis, de localización en el retropubis, posee un importante valor anastomótico ya que constituye una comunicación entre el sistema de los vasos ilíacos internos y externos. Presentamos a una mujer de 87 a˜nos, que tras una caída casual fue diagnosticada de fractura osteoporótica de las ramas pubianas izquierdas asociada a la lesión de la Corona Mortis, lo que provocó un grave cuadro de inestabilidad hemodinámica. Tras una angiografía con embolización supraselectiva del vaso lesionado y a la transfusión de varios hemoderivados la paciente evolucionó satisfactoriamente siendo dada de alta a los pocos días (AU)

Low-energy osteoporotic pelvic fractures in the elderly are a very common problem. They are usually stable fractures, non-life threatening and only require conservative treatment. The pelvic bone structure is closely related to important vascular structures. The Corona Mortis, located in the retropubis, has an important anastomotic value as it serves as communication between the internal and external iliac vessels. The case is presented of an 87 year-old woman, who, after a casual fall, was diagnosed with an osteoporotic fracture of the left pubic rami associated to a lesion of the Corona Mortis, which led to a severe picture of haemodynamic instability. After angiography with supra-selective embolisation of the lesioned vessel, and the transfusion of several haemoderivatives, the patient progressed satisfactorily, and was discharged after a few days (AU)

[Severe haemorrhage secondary to an osteoporotic pelvic fracture: presentation of a case]. / Hemorragia severa secundaria a fractura osteoporótica de la pelvis: a propósito de un caso.

Low-energy osteoporotic pelvic fractures in the elderly are a very common problem. They are usually stable fractures, non-life threatening and only require conservative treatment. The pelvic bone structure is closely related to important vascular structures. The Corona Mortis, located in the retropubis, has an important anastomotic value as it serves as communication between the internal and external iliac vessels. The case is presented of an 87 year-old woman, who, after a casual fall, was diagnosed with an osteoporotic fracture of the left pubic rami associated to a lesion of the Corona Mortis, which led to a severe picture of haemodynamic instability. After angiography with supra-selective embolisation of the lesioned vessel, and the transfusion of several haemoderivatives, the patient progressed satisfactorily, and was discharged after a few days.