An intelligent tutoring system for supporting active learning: A case study on predictive parsing learning.

The way in which people learn and institutions teach is changing due to the ever-increasing impact of technology. People access the Internet anywhere, anytime and request online training. This has brought about the creation of numerous online learning platforms which offer comprehensive and effective educational solutions which are 100% online. These platforms benefit from intelligent tutoring systems that help and guide students through the learning process, emulating the behavior of a human tutor. However, these systems give the student little freedom to experiment with the knowledge of the subject, that is, they do not allow him/her to propose and carry out tasks on his/her own initiative. They are very restricted systems in term of what the student can do, as the tasks are defined in advance. An intelligent tutoring system is proposed in this paper to encourage students to learn through experimentation, proposing tasks on their own initiative, which involves putting into use all the skills, abilities tools and knowledge needed to successfully solve them. This system has been designed developed and applied for learning predictive parsing techniques and has been used by Computer Science students during four academic courses to evaluate its suitability for improving the student's learning process.

Effects of long-term exposure to an extremely low frequency magnetic field (15 µT) on selected blood coagulation variables in OF1 mice.

The long-term exposure of OF1 mice to an extremely low frequency magnetic field (ELF-MF; 50 Hz, 15 µT [rms]) has been associated with the appearance of leukaemia. Neoplasms are usually accompanied by changes in haemostatic processes but reports on changes in blood coagulation following exposure to an ELF-MF are scarce and rather fragmentary. The aim of the present work was to determine whether any global or partial coagulation variables are modified after such long-term exposure. A parental generation of six week-old OF1 mice was exposed to an artificial ELF-MF for 14 weeks. Mating was then allowed, and the resulting filial generation raised until the age of 31-35 weeks within the same ELF-MF. Control animals were subjected only to the magnetic field of the Earth. Whole blood samples were extracted from the anesthetised filial generation of mice by cardiac puncture. White blood cells (WBC) were counted, the activated partial thromboplastin time (APTT) and prothrombin time (PT) determined, and plasma fibrinogen, reptilase time (RT), and factor VIII activity examined. The similarity between the results for the present control animals and those recorded in the literature for human blood render OF1 mice a suitable study model. The differences in the studied coagulation variables were largely owed simply to sex. However, the females showed a very significant shortening of the PT time associated with ELF-MF exposure. Exposure also caused significant increases in the female APTT and RT values, and in general reduced the differences between the sexes.

Pregnancy rates in hair sheep after Ovsynch synchronization and a combined intracervical fixed-time artificial insemination and 10-day mating period.

AIM: This study aimed to evaluate the pregnancy rates in hair ewes using an Ovsynch synchronization protocol under a breeding system that combines fixed-time insemination plus a 10-day mating period as an alternative. MATERIALS AND METHODS: Through an experimental study (n=27), ewes were randomly located into one of three treatments: (1) Pre-synch (n=9): Prostaglandin F2α (PGF2α)+Gonadotropin-releasing hormone (GnRH)+PGF2α+GnRH; (2) Ovsynch (n=9): GnRH+PGF2α+GnRH; and (3) control: Ewes bred by natural mating (NM) (n=9). Ewes were fixed-time inseminated (fixed-time artificial insemination [FTAI]) with fresh semen, collected just before the insemination time through vaginoscopy at 16 h after the second GnRH (gonadorelin) injection. Each experimental group was placed separately during 15 days and, after this time, fertile rams were allowed back with ewes for a 10-day mating period. Control group ewes remained with the rest of the herd suitable for breeding and were bred under NM. Pregnancy diagnosis was performed by ultrasound at 28-, 56-, and 84-day post-breeding to differentiate between FTAI and NM pregnancies. Total (FTAI±NM) pregnancy rates at 56-day post-breeding were used to compared Pre-synch, Ovsynch, and control. For this purpose, two-tailed proportions comparison z-test was used with a 95% confidence level, for testing as the null hypothesis whether two proportions were equal. RESULTS: Pregnancy rates were higher in control ewes (66.4%) than FTAI (46.6%). When pregnancy rates after a 10-day mating period (40%) were added, the final rate (86.6%) was significantly (p<0.05) higher in Ovsynch-based protocols. The pregnancy rate was significantly lower in FTAI ewes compared to FTAI +10-day mating group (p<0.05). The overall pregnancy rate was 88.0, 85.7, and 67.0 (p>0.05) for Pre-synch, Ovsynch, and control ewes, respectively. CONCLUSION: These results provide evidence on the benefits of combined FTAI protocols for improving the reproductive efficiency of sheep.

A rotary and reciprocating scintillator based fast-ion loss detector for the MAST-U tokamak.

The design and unique feature of the first fast-ion loss detector (FILD) for the Mega Amp Spherical Tokamak - Upgrade (MAST-U) is presented here. The MAST-U FILD head is mounted on an axially and angularly actuated mechanism that makes it possible to independently adapt the orientation [0°, 90°] and radial position [1.40 m, 1.60 m] of the FILD head, i.e., its collimator, thus maximizing the detector velocity-space coverage in a broad range of plasma scenarios with different q95. The 3D geometry of the detector has been optimized to detect fast-ion losses from the neutral beam injectors. Orbit simulations are used to calculate the strike map and predict the expected signals. The results show a velocity-space range of [4 cm, 13 cm] in gyroradius and [30°, 85°] in pitch angle, covering the entire neutral beam ion energy range. The optical system will provide direct sight of the scintillator and simultaneous detection with two cameras, giving high spatial and temporal resolution. The MAST-U FILD will shed light on the dominant fast-ion transport mechanisms in one of the world's two largest spherical tokamaks through absolute measurements of fast-ion losses.

Cell-sized lipid vesicles for cell-cell synaptic therapies.

Cell-sized lipid vesicles (CLVs) have shown great promise for therapeutic and artificial cell applications, but their fragility and short shelf life has hindered widespread adoption and commercial viability. We present a method to circumvent the storage limitations of CLVs such as giant unilamellar vesicles (GUVs) and single-compartment multisomes (SCMs) by storing them in a double emulsion precursor form. The double emulsions can be stored for at least 8 months and readily converted into either GUVs or SCMs at any time. In this study, we investigate the interfacial parameters responsible for this morphological change, and we also demonstrate the therapeutic potential of CLVs by utilizing them to present a transmembrane protein, neuroligin-2, to pancreatic ß-cells, forming cell-cell synapses that stimulate insulin secretion and cellular growth.

A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors.

A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.

Effects of a low-fat diet with antioxidant supplementation on biochemicalmarkers of multiple sclerosis long-term care residents / Efecto de una dieta baja en grasas con suplementación de antioxidantes en los marcadores bioquímicos de residentes de larga estancia con esclerosis múltiple

Introduction: Multiple sclerosis (MS) treatment options are primarily limited to immunomodulatory therapies in MS non-progressive forms. Nutrition intervention studies suggest that diet may be considered as a complementary treatment to control disease progression. Therefore, dietary intervention may help to improve wellness and ameliorate symptoms of MS patients. Objectives: To assess the effect of a low-fat diet with antioxidant supplementation on biochemical markers of institutionalized patients with progressive forms of multiple sclerosis. Methods: A randomized prospective placebo-controlled study involving 9 participants, 5 of them assigned to the intervention group (low-fat diet and antioxidant supplementation) and the other 4 to the placebo group (low-fat diet). The effect of the dietary intervention, involving diet modification and antioxidant supplementation, was examined for 42 days by measuring anthropometric, biochemical parameters and oxidative stress markers in blood at baseline (day 0), intermediate (day 15) and end (day 42) stages of the treatment. Results: The intervention group obtained C reactive protein levels significantly lower than those observed in the corresponding placebo group at the end of the study. Oxidative stress and inflammatory markers isoprostane 8-iso-PGF2α and interleukine IL-6 values also diminished after dietary intervention in the intervention group. Catalase activity increased significantly in the intervention group prior antioxidant supplementation. No significant differences were observed in other oxida-tive stress markers. Conclusions: The results suggest that diet and dietary supplements are involved in cell metabolism modulation and MS-related inflammatory processes. Consequently, low fat diets and antioxidant supplements may be used as complementary therapies for treatment of multiple sclerosis (AU)

Introducción: Las posibilidades de tratamiento de la esclerosis múltiple (EM) se encuentran limitadas principalmente a terapias con inmumoduladores en las formas no progresivas de EM. Los estudios de intervención nutricional sugieren que la dieta puede considerarse como un tratamiento alternativo para controlar la progresión de la enfermedad. Por esta razón, las intervenciones en la dieta pueden ayudar a mejorar el bienestar y mejorar los síntomas de los pacientes con EM. Objetivos: Valorar el efecto de una dieta pobre en grasas con suplementación de antioxidantes en los marcadores bioquímicos de pacientes institucionalizados que presentan formas progresivas de EM. Métodos: Se realizó un estudio prospectivo aleatorizado controlado por placebo con 9 participantes, 5 de los cuales se asignan al grupo de intervención (dieta baja en grasas y suplementación antioxidante) y los 4 restantes al grupo placebo (dieta baja en grasas). Se evaluó el efecto de la intervención dietética que supone modificación de la dieta e introducción de antioxidantes durante 42 días mediante valoraciones de parámetros antropométricos y bioquímicos y marcadores del estrés oxidativo en sangre y orina en las etapas inicial (día 0), intermedia (día 15) y final (día 42) del tratamiento. Resultados: Se obtuvieron niveles de proteína C reactiva significativamente inferiores en el grupo de intervención con respecto al grupo placebo al final del estudio. Los marcadores de estrés oxidativo e inflamación: isoprostanos 8-iso-PGF2α e interleucina IL-6 también disminuyeron en el grupo de intervención después de la intervención dietética. La actividad de la enzima catalasa aumentó de forma significativa en el grupo de intervención antes de la suplementación con antioxidantes. No se observaron diferencias significativas en otros marcadores de estrés oxidativo. Conclusiones: Los resultados obtenidos sugieren que la dieta y los suplementos dietéticos están involucrados en la modulación del metabolismo celular y los procesos de inflamación de la EM. En consecuencia, las dietas bajas en grasas y los suplementos antioxidantes podrían ser utilizados como terapias alternativas en el tratamiento de la EM (AU)

Effects of a low-fat diet with antioxidant supplementation on biochemical markers of multiple sclerosis long-term care residents.

INTRODUCTION: Multiple sclerosis (MS) treatment options are primarily limited to immunomodulatory therapies in MS non-progressive forms. Nutrition intervention studies suggest that diet may be considered as a complementary treatment to control disease progression. Therefore, dietary intervention may help to improve wellness and ameliorate symptoms of MS patients. OBJECTIVES: To assess the effect of a low-fat diet with antioxidant supplementation on biochemical markers of institutionalized patients with progressive forms of multiple sclerosis. METHODS: A randomized prospective placebo-controlled study involving 9 participants, 5 of them assigned to the intervention group (low-fat diet and antioxidant supplementation) and the other 4 to the placebo group (low-fat diet). The effect of the dietary intervention, involving diet modification and antioxidant supplementation, was examined for 42 days by measuring anthropometric, biochemical parameters and oxidative stress markers in blood at baseline (day 0), intermediate (day 15) and end (day 42) stages of the treatment. RESULTS: The intervention group obtained C reactive protein levels significantly lower than those observed in the corresponding placebo group at the end of the study. Oxidative stress and inflammatory markers isoprostane 8-iso-PGF2α and interleukine IL-6 values also diminished after dietary intervention in the intervention group. Catalase activity increased significantly in the intervention group prior antioxidant supplementation. No significant differences were observed in other oxidative stress markers. CONCLUSIONS: The results suggest that diet and dietary supplements are involved in cell metabolism modulation and MS-related inflammatory processes. Consequently, low fat diets and antioxidant supplements may be used as complementary therapies for treatment of multiple sclerosis.

Introducción: Las posibilidades de tratamiento de la esclerosis múltiple (EM) se encuentran limitadas principalmente a terapias con inmumoduladores en las formas no progresivas de EM. Los estudios de intervención nutricional sugieren que la dieta puede considerarse como un tratamiento alternativo para controlar la progresión de la enfermedad. Por esta razón, las intervenciones en la dieta pueden ayudar a mejorar el bienestar y mejorar los síntomas de los pacientes con EM. Objetivos: Valorar el efecto de una dieta pobre en grasas con suplementación de antioxidantes en los marcadores bioquímicos de pacientes institucionalizados que presentan formas progresivas de EM. Métodos: Se realizó un estudio prospectivo aleatorizado controlado por placebo con 9 participantes, 5 de los cuales se asignan al grupo de intervención (dieta baja en grasas y suplementación antioxidante) y los 4 restantes al grupo placebo (dieta baja en grasas). Se evaluó el efecto de la intervención dietética que supone modificación de la dieta e introducción de antioxidantes durante 42 días mediante valoraciones de parámetros antropométricos y bioquímicos y marcadores del estrés oxidativo en sangre y orina en las etapas inicial (día 0), intermedia (día 15) y final (día 42) del tratamiento. Resultados: Se obtuvieron niveles de proteína C reactiva significativamente inferiores en el grupo de intervención con respecto al grupo placebo al final del estudio. Los marcadores de estrés oxidativo e inflamación: isoprostanos 8-iso-PGF2e interleucina IL-6 también disminuyeron en el grupo de intervención después de la intervención dietética. La actividad de la enzima catalasa aumentó de forma significativa en el grupo de intervención antes de la suplementación con antioxidantes. No se observaron diferencias significativas en otros marcadores de estrés oxidativo. Conclusiones: Los resultados obtenidos sugieren que la dieta y los suplementos dietéticos están involucrados en la modulación del metabolismo celular y los procesos de inflamación de la EM. En consecuencia, las dietas bajas en grasas y los suplementos antioxidantes podrían ser utilizados como terapias alternativas en el tratamiento de la EM.

Growth variations in OF1 mice following chronic exposure of parental and filial generations to a 15 µT, 50 Hz magnetic field.

The growth of a first filial generation (F1) of OF1 mice was studied following chronic exposure of their mothers and themselves to a magnetic field of 15 µT (rms) and 50 Hz. The parental generation (F0) remained for 98 days in this field, after that time they were mated, went through pregnancy, birth, lactation, and the weaning of their offspring in this field. The latter remained exposed to this field until reaching adulthood (220 days). Control animals were treated in the same way but were exposed only to the Earth's magnetic field. The growth data for the offspring were analyzed using a generalization of Koop's equation. Using this model, four phases were identified: lactation growth acceleration, post-weaning growth acceleration, growth stabilization, and a stationary phase. Exposure to the artificial magnetic field was associated with a marked increase in maximum growth rate in the exposed animals during the post-weaning growth acceleration phase, and with a reduction in mass gain in the F1 mice (especially in males) during the third of these phases. In addition, the growth stabilization phase was more extended in exposed females and shorter in exposed males than in the control animals. Furthermore, statistically significant differences were seen between the mean body masses of exposed and control F1 males from 49-123 days. Exposure to the artificial magnetic field might have been associated with the stimulated growth rate seen over the noticeably shortened second and third growth phases (leaving these animals lighter by the stationary phase compared to controls) and a possible acceleration of aging. Both processes could be responsible for the stationary phase being reached at an earlier age, especially in males.

An analysis of postnatal growth in OF1 mice within an interval of 1-220 days of age.

The body weight growth of OF1 mice, both females and males, from day of birth to 220 days old is studied herein. After comparison of different theoretical models, an extension of Koops's multiphasic functions, the tetraphasic, is proposed as the best choice in so wide a time interval in mouse development. This function has allowed us to take into account different aspects of growth. Coefficients and phases of this function are characterized. The end of the first phase was established at 17 days of age. The second phase finished at 35 days of age in females and at 39 days in males. This difference increased during the third phase: the end of it was at 173 days of age in males, and at 160 days in females. The end of the fourth phase in OF1 mice would be produced after 220 days of age. Inflexion points in every four phases, in females and males, are situated. The biggest weight increase occurred in the second phase in both sexes, specially in males (1.26 g per day). Biological meanings of every phase are also discussed. The short lifetime of rodents have allowed us to study a great number of growth phases in a short period of time. Thus the present analysis could be a good starting point for the study of growth curves in other species of mammals.

Electrostatic recognition between enzyme and inhibitor: interaction between papain and leupeptin.

Electrostatic forces are involved in a wide variety of molecular interactions that are of biological interest, including, among others, DNA-Protein interactions, protein folding, and the interactions between enzymes and their substrates and inhibitors. In this work, the interaction between papain and an inhibitor, leupeptin, is analyzed from the point of view of their electrostatic interaction. The computations enable one to suggest that negatively charged amino acids located in the region of the active site are responsible for creating an environment that enables efficient binding of the inhibitor. This binding occurs despite the fact that the net global charge of both molecules is positive; an explanation for this apparent contradiction is proposed.

An unusual complication of appendicitis in childhood.

Mesenteric venous thrombosis has not been reported after an appendicectomy in the pediatric literature. We report on a special and very unusual complication in a girl who presented mesenteric venous thrombosis (MVT) following an appendicectomy for gangrenous appendicitis. The early diagnosis of this entity is vital in order to start the anticoagulation treatment which could allow preservation of bowel viability. The therapy should be continued for a long time to decrease the risk of relapse.

Mutational analysis of influenza A virus nucleoprotein: identification of mutations that affect RNA replication.

The influenza A virus nucleoprotein (NP) is a multifunctional polypeptide which plays a pivotal role in virus replication. To get information on the domains and specific residues involved in the different NP activities, we describe here the preparation and characterization of 20 influenza A virus mutant NPs. The mutations, mostly single-amino-acid substitutions, were introduced in a cDNA copy of the A/Victoria/3/75 NP gene and, in most cases, affected residues located in regions that were highly conserved across the NPs of influenza A, B, and C viruses. The mutant NPs were characterized (i) in vivo (cell culture) by analyzing their intracellular localization and their functionality in replication, transcription, and expression of model RNA templates; and (ii) in vitro by analyzing their RNA-binding and sedimentation properties. The results obtained allowed us to identify both a mutant protein that accumulated in the cytoplasm and mutations that altered the functionality and/or the oligomerization state of the NP polypeptide. Among the mutations that reduced the NP capability to express chloramphenicol acetyltransferase protein from a model viral RNA (vRNA) template, some displayed a temperature-sensitive phenotype. Interestingly, four mutant NPs, which showed a reduced functionality in synthesizing cRNA molecules from a vRNA template, were fully competent to reconstitute complementary ribonucleoproteins (cRNPs) capable of synthesizing vRNAs, which in turn yielded mRNA molecules. Based on the phenotype of these mutants and on previously published observations, it is proposed that these mutant NPs have a reduced capability to interact with the polymerase complex and that this NP-polymerase interaction is responsible for making vRNPs switch from mRNA to cRNA synthesis.

Mesenteric venous thrombosis after appendicectomy in a child: clinical case and review of the literature.

Mesenteric venous thrombosis (MVT) after appendicectomy has not been reported in the pediatric literature. This complication is associated with significant morbidity and mortality rates in adults. The report of this case attempts to analyze the features found in an appendicectomized child documented by radiological examination and surgery before and after starting heparin therapy. Anticoagulation treatment should be started as soon as possible and continued for a long time to decrease the risk of relapse.

Electrostatics of the phospholipase-membrane interaction.

The electrostatic interaction of the Phospholipase A2 (PLA2)-membrane complex in the presence and absence of calcium is analysed by the computation of the electrostatic profiles of the components and the complex. The electrostatic potential was computed by using of the program MOLPOT that implement the boundary element method to solve the electrostatic problem. It considers a closed surface in three dimensions that contains the macromolecule that follows as close as possible the macromolecule shape. The results show that the presence of calcium ions contributes to the stability of the complex and at the same time creates a favourable electrostatic potential pattern that may be favourable for the lipolysis of the membrane components.

[Adrenocortical tumors in children]. / Tumores adrenocorticales en niños.

Adrenocortical tumors are uncommon in childhood. The incidence of these tumors is about 0.3-0.4% of all the solid tumors in childhood. Because of its low incidence, there are no established protocols or uniform histological classification. Most of these endocrine tumors are hormone producing, causing virilization, Cushing's syndrome, feminization, hiperaldosteronism or hipoglicemy. Only a few of these do not produce hormones. The treatment is always surgical. The efficacy of another treatments (chemotherapy or radiotherapy) has not been demonstrated in infancy. It prognosis depends on the age and the resectability.

Nuevas perspectivas en la actitud quirurgica ante el niño quemado / Surgical management of burned children: new perspectives

Desde el año 1970 en que Janzekovic preconizo el tratamiento quirurgico precoz de los niños con quemaduras darmicas profundas, podemos afirmar que stas se han convertido en una de las indicaciones quirurgicas por excelencia. En esta patologia, el incremento en las tasas de supervivencia la mejoria en los resultados van estrachamente unidos a una rapida ex resis de los tejidos lesionados y su sustitucion precoz por una cobertura cutanea definitiva. Se presenta la experiencia en el tratamiento quirurgico del niño quemado haciendo hincapi en le manejo de sustitutos temporales del pi (apositos biosintaticos y homoinjertos cutaneos) y coberturas definitivas (autoinjerto y cultivo de queratinocitos)

Nuevas perspectivas en la actitud quirurgica ante el niño quemado / Surgical management of burned children: new perspectives

Desde el año 1970 en que Janzekovic preconizo el tratamiento quirurgico precoz de los niños con quemaduras darmicas profundas, podemos afirmar que stas se han convertido en una de las indicaciones quirurgicas por excelencia. En esta patologia, el incremento en las tasas de supervivencia la mejoria en los resultados van estrachamente unidos a una rapida ex resis de los tejidos lesionados y su sustitucion precoz por una cobertura cutanea definitiva. Se presenta la experiencia en el tratamiento quirurgico del niño quemado haciendo hincapi en le manejo de sustitutos temporales del pi (apositos biosintaticos y homoinjertos cutaneos) y coberturas definitivas (autoinjerto y cultivo de queratinocitos)