264 research outputs found
Defect spectroscopy of single ZnO microwires
The point defects of single ZnO microwires grown by carbothermal reduction were studied by microphotoluminescence, photoresistance excitation spectra, and resistance as a function of the temperature. We found the deep level defect density profile along the microwire showing that the concentration of defects decreases from the base to the tip of the microwires and this effect correlates with a band gap narrowing. The results show a characteristic deep defect levels inside the gap at 0.88 eV from the top of the VB. The resistance as a function of the temperature shows defect levels next to the bottom of the CB at 110 meV and a mean defect concentration of 4 1018 cm3 . This combination of techniques allows us to study the band gap values and defects states inside the gap in single ZnO microwires and opens the possibility to be used as a defect spectroscopy method.Fil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferreyra, J. M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Zapata, C.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Barzola Quiquia, J.. University of Leipzig; AlemaniaFil: Iikawa, F.. Instituto de Física “Gleb Wataghin"; BrasilFil: Esquinazi, P.. University of Leipzig; AlemaniaFil: Huleani, S. P.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: de Lima, M. M.. Universidad de Valencia; EspañaFil: Cantarero, A.. Universidad de Valencia; Españ
Students’ Factors Affecting Undergraduates’ Perceptions of their Teaching and Learning Process within ECTS Experience
Introduction: In the present study, we investigated the potential factors that influenced the level of students satisfaction with the teaching–learning process (TLP), from the perspective of students participating in the European Credit Transfer System (ECTS) experience. Method: A total of 1490 students from the Universities of Almería and Granada (Spain) participated in an evaluation of their class discipline area. They completed the new revised protocol for evaluating the ECTS experience. Analyses of variance were carried out, taking the following factors as independent variables: student's grade average, year in school, study discipline, credit load in terms of ECTS credits assigned to a subject, the e-learning approach. Perception of the TLP was used as the dependent variable. Results: The data analyses showed variability of the degree of statistically significance among the factors that influenced students’ perceptions of the TLP. These factors included: Student's grade average (in favor of high performers), year in school (in favor of earlier years), ECTS load (in favor of subjects with a medium load of credits), and e-learning (in favor of its use). These research findings provided evidence to explore the delineation of a potential profile of factors that trigger a favorable perception of the TLP. Discussion and Conclusion: The present findings certainly have implications to deepen our understanding of the core beliefs, commitment, and the experience in shaping the implementation of the European Higher Education Area through the ECTS
One, Two, Three ... An Explosive Outflow in IRAS 123266245 revealed by ALMA
In the last years there has been a substantial increase in the number of the
reported massive and luminous star-forming regions with related explosive
outflows thanks to the superb sensitivity and angular resolution provided by
the new radio, infrared, and optical facilities. Here, we report one more
explosive outflow related with the massive and bright star-forming region IRAS
123266245 using Band 6 sensitive and high angular resolution (0.2)
Atacama Large Millimeter/Submillimeter Array (ALMA) observations. We find over
10 molecular and collimated well-defined streamers, with Hubble-Lemaitre like
expansion motions, and pointing right to the center of a dusty and molecular
shell (reported for the first time here) localized in the northern part of the
UCHII region known as G301.1A. The estimated kinematic age, and energy for the
explosion are 700 yrs, and 10 erg, respectively. Taking into
account the recently reported explosive outflows together with IRAS
123266245, we estimate an event rate of once every 90 yr in our Galaxy,
similar to the formation rate of massive stars.Comment: Accepted to The Astrophysical Journal Letter
Changes in toxin content, biomass and pigments of the dinoflagellate Alexandrium minutum during nitrogen refeeding and growth into nitrogen or phosphorus stress
Two strains oi the paralytic shellfish toxin (PST) producing dinoflagellate Alexandrium
minutum Halim (highly toxic ALl V and weakly toxic AL2V) were grown in batch culture with either
nitrate or phosphate as the limiting nutrient. In comparison with cells of the strain AL1V, cells of AL2V
grew at a similar C-specific Tale, had a higher C/N ratio, and lower ratios of chl a/chl C2and chl a/peridinin.
Neither chlorophylls flor carotenoids could be used to estimate C-biomass, N-biomass or toxin
content for this organismo The toxin profile for both strains was dominated (up to 95 %) by the gonyautoxin
GTX4, with smaller proportions of GTX1, GTX2 and GTX3. The Tale of toxin synthesis for both
strains was greatest 1 to 2 d after the N-refeeding of N-deprived cells, with the net Tale of toxin syn-
.thesis exceeding that of C-biomass and cell division by a factor of up to 4. Toxin synthesis was not
enhanced by short-term P-stress. N-stress alone led to a decrease in toxin cell-I, but P-stress followed
by N-stress did not result in such a decline, implicating phosphorus in the regulation of toxin metabolism.
Although arginine is a majar precursor for PST synthesis, taurine, glycine, glutamine, and cell N
showed similar relations to that observed for arginine with respect to toxin contento Furthermore, the
mole ratio of arginine/toxin could vary by a factor of up to 5 between AL1V and AL2V at peak values
of toxin cell-1, and by more than 5 within a strain when growing under different conditions. These
observations suggest that the relationship between free arginine content and toxin content is complex.
No explanation for the higher toxin content of AL1V is apparent, except that AL1V has a higher
N-content per cell and this may be conducive to a higher Tale of synthesis of the N-rich toxins.Publicado
Procesos deposicionales y antrópicos en el registro holoceno de la Cova de Can Sadurní (Begues, Barcelona, España): aportaciones microestratigráficas
[spa] El estudio geoarqueológico y microestratigráfico de la secuencia de la Cova de Can Sadurní (Begues, Barcelona) ofrece una variabilidad de procesos deposicionales de tipo detrítico y antrópico que en determinadas etapas se alternan y repercuten en los procesos diagenéticos localizados. La secuencia cultural del yacimiento va desde el Epipaleolítico hasta época Romana bajo imperial con algunas interrupciones cronoculturales. Durante el Epipaleolítico y Mesolítico los aportes solifluidales son los responsables de la sedimentación. A partir del Neolítico, movimientos de masa y procesos coluvionales son los dominantes. Se distinguen flujos densos principalmente durante el Neolítico antiguo cardial y postcardial inicial; también se localizan pero con menor extensión durante el Neolítico medio postcardial, Neolítico final/Calcolítico y en el Bronce inicial. Los aportes coluvionales no laminados aparecen en el resto de la secuencia. Estos episodios se alternan con fases de estabilidad en el medio en el que la tasa de sedimentación detrítica es menor o casi inexistente y es reemplazada por los aportes procedentes de las actividades de estabulación localizados in situ durante el Neolítico epicardial y postcardial inicial; aunque ya se constaten evidencias desde el Neolítico antiguo cardial. Asociados a estos contextos, los procesos hidromórficos se acentúan dando lugar a la formación de vivianita, fosfato de hierro, propia de lugares reductores con un gran contenido orgánico.[eng] Depositional and anthropic processes in the Holocene record of the Can Sadurní cave (Begues, Barcelona, Spain): microstratigraphic contributions ABSTRACT The geoarchaeological and microstratigraphic study of the Can Sadurní cave sequence (Begues, Barcelona) reveals the presence of detrital and anthropogenic depositional processes, alternating at certain stages. These influenced the location of the diagenetic processes. The cultural sequence of the site ranges from Epipaleolithic to Late Roman Empire, with some chronocultural interruptions. During the Epipaleolithic and Mesolithic, solifluction processes were responsible for sedimentation. From the Neolithic, mass wasting and colluvial processes were dominant. Dense flows are distinguished mainly during the Cardial Early Neolithic and Early Postcardial. This type of contribution is also present to a lesser extent during the Postcardial Middle Neolithic, Late Neolithic/Chalcolithic and Early Bronze Age. Non-laminated colluvial inputs appear in the rest of the sequence. These episodes alternate with periods of stability, in which the rate of detrital sedimentation is lower or almost non-existent. This is replaced by the presence of in situ stabling areas during the Epicardial and Early Postcardial Neolithic, although evidence is detected from the Cardial Early Neolithic. Associated with these contexts, hydromorphic processes are accentuated leading to the formation of vivianite -an iron phosphate mineral- typical of a reducing medium with high organic matter
A Mathematical Description of the Bone Marrow Dynamics during CAR T-Cell Therapy in B-Cell Childhood Acute Lymphoblastic Leukemia
Chimeric Antigen Receptor (CAR) T-cell therapy has demonstrated high rates of response in recurrent B-cell Acute Lymphoblastic Leukemia in children and young adults. Despite this success, a fraction of patients' experience relapse after treatment. Relapse is often preceded by recovery of healthy B cells, which suggests loss or dysfunction of CAR T-cells in bone marrow. This site is harder to access, and thus is not monitored as frequently as peripheral blood. Understanding the interplay between B cells, leukemic cells, and CAR T-cells in bone marrow is paramount in ascertaining the causes of lack of response. In this paper, we put forward a mathematical model representing the interaction between constantly renewing B cells, CAR T-cells, and leukemic cells in the bone marrow. Our model accounts for the maturation dynamics of B cells and incorporates effector and memory CAR T-cells. The model provides a plausible description of the dynamics of the various cellular compartments in bone marrow after CAR T infusion. After exploration of the parameter space, we found that the dynamics of CAR T product and disease were independent of the dose injected, initial B-cell load, and leukemia burden. We also show theoretically the importance of CAR T product attributes in determining therapy outcome, and have studied a variety of possible response scenarios, including second dosage schemes. We conclude by setting out ideas for the refinement of the model.This work was partially supported by the Fundacion Espanola para la Ciencia y la Tecnologia (UCA PR214), the Asociacion Pablo Ugarte (APU, Spain), Junta de Comunidades de Castilla-La Mancha (SBPLY/17/180501/000154), Ministry of Science and Technology, Spain (PID2019110895RB-I00), and Inversion Territorial Integrada de la Provincia de Cadiz (ITI-0038-2019)
Personal Self-Regulation, Learning Approaches, Resilience and Test Anxiety in Psychology Students
La autorregulación personal se ha conceptuado como una meta-habilidad, de orden meta-motivacional y meta-afectivo. Esta investigación pretendió establecer las relaciones de asociación e interdependencia con otras variables motivacionales-afectivas relevantes. Participaron un total de 121 alumnos de 2º y 4º curso de Psicología, de la Universidad de Almería (España). Se realizaron análisis correlacionales bivariados de Pearson, ANOVAs y MANOVAs. Los resultados mostraron una relación significativa de
ferencial entre la autorregulación personal y cada tipo de enfoque de aprendizaje, positiva con la tenacidad y con control resiliente, y negativa con la preocupación. Se evidencia el valor de esta construcción psicoeducativa presagio de las variables estudiadas.Personal self-regulation has been conceptualized as meta-hability, a meta-motivational and meta-affective variable. The objective of this investigation was to establish association and interdependence relationships with other important motivational-affective variables. There were 121 participants in the study, all of them students from the second and fourth year of the Psychology degree program at the University of Almería (Spain). Pearson bivariate correlational analyses, ANOVAs and MANOVAs were car
ried out. Self-regulation was shown to have a signifi cant relationship with each type of learning approach, positive with tenacity and with resilient control, and a negative relationship with worry. Personal self-regulation is shown to have value as a presage psychological construct within the study of motivational-affective variables in Education
Catching the Butterfly and the Homunculus of n Carinae with ALMA
The nature and origin of the molecular gas component located in the circumstellar vicinity of n Carinae are still far from being completely understood. Here, we present Atacama Large Millimeter/submillimeter Array CO(3-2) observations with a high angular resolution (∼0.″15) and a great sensitivity that are employed to reveal the origin of this component in n Carinae. These observations reveal much higher velocity (-300 to +270 km s-1) blue- and redshifted molecular thermal emission than previously reported, which we associate with the lobes of the Homunculus Nebula, and which delineates very well the innermost contours of the red- and blueshifted lobes likely due to limb brightening. The inner contour of the redshifted emission was proposed to be a disrupted torus, but here we reveal that it is at least part of the molecular emission originating from the lobes and/or the expanding equatorial skirt. On the other hand, closer to systemic velocities (±100 km s-1), the CO molecular gas traces an inner butterfly-shaped structure that is also revealed at near-IR and mid-IR wavelengths as the region in which the shielded dust resides. The location and kinematics of the molecular component indicate that this material has formed after the different eruptions of n Carinae.Fil: Zapata, Luis A.. Universidad Nacional Autónoma de México; MéxicoFil: Loinard, Laurent. Universidad Nacional Autónoma de México; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Toalá, Jesús A.. Universidad Nacional Autónoma de México; MéxicoFil: González, Ricardo F.. Universidad Nacional Autónoma de México; MéxicoFil: Rodríguez, Luis F.. Universidad Nacional Autónoma de México; MéxicoFil: Gull, Theodore R.. No especifíca;Fil: Morris, Patrick W.. No especifíca;Fil: Menten, Karl M.. Max Planck Institute For Radio Astronomy; AlemaniaFil: Kamiński, Tomasz. Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences; Poloni
Effect of sugammadex on processed EEG parameters in patients undergoing robot-assisted radical prostatectomy
Background: Sugammadex has been associated with increases in the bispectral index (BIS). We evaluated the effects of
sugammadex administration on quantitative electroencephalographic (EEG) and electromyographic (EMG) measures.
Methods: We performed a prospective observational study of adult male patients undergoing robot-assisted radical
prostatectomy. All patients received a sevoflurane-based general anaesthetic and a continuous infusion of rocuronium,
which was reversed with 2 mg kg1 of sugammadex i.v. BIS, EEG, and EMG measures were captured with the BIS Vista™
monitor.
Results: Twenty-five patients were included in this study. Compared with baseline, BIS increased at 4e6 min (b coefficient: 3.63; 95% confidence interval [CI]: 2.22e5.04; P<0.001), spectral edge frequency 95 (SEF95) increased at 2e4 min (b
coefficient: 0.29; 95% CI: 0.05e0.52; P¼0.016) and 4e6 min (b coefficient: 0.71; 95% CI: 0.47e0.94; P<0.001), and EMG
increased at 4e6 min (b coefficient: 1.91; 95% CI: 1.00e2.81; P<0.001) after sugammadex administration. Compared with
baseline, increased beta power was observed at 2e4 min (b coefficient: 93; 95% CI: 1e185; P¼0.046) and 4e6 min (b coefficient: 208; 95% CI: 116e300; P<0.001), and decreased delta power was observed at 4e6 min (b coefficient: 526.72; 95%
CI: 778 to 276; P<0.001) after sugammadex administration. Neither SEF95 nor frequency band data analysis adjusted
for EMG showed substantial differences. None of the patients showed clinical signs of awakening.
Conclusions: After neuromuscular block reversal with 2 mg kg1 sugammadex, BIS, SEF95, EMG, and beta power showed
small but statistically significant increases over time, while delta power decreased
- …