Phase Diagram of Multilayer Magnetic Structures

Multilayer "ferromagnet-layered antiferromagnet" (Fe/Cr) structures frustrated due to the roughness of layer interfaces are studied by numerical modeling methods. The "thickness-roughness" phase diagrams for the case of thin ferromagnetic film on the surface of bulk antiferromagnet and for two ferromagnetic layers separated by an antiferromagnetic interlayer are obtained and the order parameter distributions for all phases are found. The phase transitions nature in such systems is considered. The range of applicability for the "magnetic proximity model" proposed by Slonczewski is evaluated.Comment: 8 pages, 8 figure

Aprovechamiento de jagueyes para el cultivo en jaula de mojarra lora (Oreochromis nilcrícus) e hibrido de mojarra (Oreochromis bornorum macho x Oreochrómis niloticus hembra) en el municipio de Aracataca, Magdalena.

El presente trabajo se realizó en la zona norte del municipio de Ara cataca, Magdalena, durante los meses de Octubre de 1987 a Abril de 1988. Se estudió la posibilidad técnica de cultivar Mójarra Lora (Oreochromis niloticus) e Híbrido de Mojarra (Oreochromis hornorum macho x Oreochro mis niloticus hembra) en jagüeyes a diferentes densidades de siembra, fueron ensayadas densidades de 50 y.100 ind/m 3 (jaulas 1 y 3, respectivamente) y Mojarra Lora 75 y 125 ind/m 3 (jaulas 2 y 4, respectivamente). Se les administró alimento concentrado comercial con 20% de proteína. Durante los 45 días Iniciales se le administró alimento en polvo en un 5% con base en el peso total de la población; luego fue disminuida la ración a la mitad y en forma de pelet. A los 75 días se les suministró el 1,5% y a partir de los 105 días se le aumentó la ración al 2,5% del peso total de la población, hasta la culminación de la investigación. Los resultados del análisis bíoestadístico reportó mejor crecimiento en los Híbridos de Mojarra que en la Mojarra Lora. No hubo significancia estadística entre las densidades 50 y 100 ind/m3; tampoco la hubo entre las densidades 75 y 125 ind/m3, por ello se recomienda mejor sembrar 100 ind/m (Híbridos de Mojarra). El costo total por kg de pescado producido fue de $823,35 en la jaula 1;$1.227,07 en la jaula 2; $587,81 en la jaula 3 y$988,92 en la jaula 4. Por lo tanto es más económico sembrar peces a una densidad de 100 ind/m3 (Híbridos de Mojarra). A los 165 días finalizó el periodo de experimentación de crecimiento de los Híbridos de Mojarra; pero debido al bajo peso presentado por la Mojarra Lora se determinó dejar 30 días más el ensayo disminuyendo las densidades a 20, 40, 60, 80 y 100 ind/jaula, obteniéndose al final Pesos promedios de 119,6 g; 116,3 g; 121,7 g; 125 g y 126,3 g en las densidades, respectivas. Se realizó el control de calidad de agua del jagüey, determinándose oxígeno, pH, dureza total, amonio, nitrito, nitrato, fosfato, temperaturá y plancton encontrándose dentro de los valores aceptados para cultivo de peces

Energy savings measures in compressed air systems

Compressed air is one of the most widely used application energies in the industry, such as good transportability, safety, purity, cleanliness, storage capacity and ease of use. In many countries, compressed air systems account for approximately 10% of the industry’s total electricity consumption. Despite all its advantages, compressed air is expensive, only between 10% and 30% of the energy consumed reaches the point of final use. Energy is lost as heat, leaks, pressure drop, misuse, among others. Energy efficiency measures such as: reducing compressor pressure, lowering air inlet temperature, adequate storage capacity, recovering residual heat from the air compressor and reducing leakage, can produce energy savings between 20% and 60%, with an average return on investment lower than 2 years. This paper analyzes the main energy efficiency measures that can be applied in the CASs, the potential energy savings, implementation costs and return rate of each of them are being calculated giving a necessary tool for companies in their objectives to reduce greenhouse gas emissions and energy consumption

Single-cell RNA sequencing reveals cancer stem-like cells and dynamics in tumor microenvironment during cholangiocarcinoma progression

Cholangiocarcinoma is a malignancy of the bile ducts that is driven by activities of cancer stem-like cells and characterized by a heterogeneous tumor microenvironment. To better understand the transcriptional profiles of cancer stem-like cells and dynamics in the tumor microenvironment during the progression of cholangiocarcinoma, we performed single-cell RNA analysis on cells collected from three different timepoints of tumorigenesis in a YAP/AKT mouse model. Bulk RNA sequencing data from TCGA (The Cancer Genome Atlas program) and ICGC cohorts were used to verify and support the finding. In vitro and in vivo experiments were performed to assess the stemness of cancer stem-like cells. We identified Tm4sf1high malignant cells as cancer stem-like cells. Across timepoints of cholangiocarcinoma formation in YAP/AKT mice, we found dynamic change in cancer stem-like cell/stromal/immune cell composition. Nevertheless, the dynamic interaction among cancer stem-like cells, immune cells, and stromal cells at different timepoints was elaborated. Collectively, these data serve as a useful resource for better understanding cancer stem-like cell and malignant cell heterogeneity, stromal cell remodeling, and immune cell reprogramming. It also sheds new light on transcriptomic dynamics during cholangiocarcinoma progression at single-cell resolution

The impact of healthy pregnancy on features of heart rate variability and pulse wave morphology derived from wrist-worn photoplethysmography

Due to the association between dysfunctional maternal autonomic regulation and pregnancy complications, tracking non-invasive features of autonomic regulation derived from wrist-worn photoplethysmography (PPG) measurements may allow for the early detection of deteriorations in maternal health. However, even though a plethora of these features-specifically, features describing heart rate variability (HRV) and the morphology of the PPG waveform (morphological features)-exist in the literature, it is unclear which of these may be valuable for tracking maternal health. As an initial step towards clarity, we compute comprehensive sets of HRV and morphological features from nighttime PPG measurements. From these, using logistic regression and stepwise forward feature elimination, we identify the features that best differentiate healthy pregnant women from non-pregnant women, since these likely capture physiological adaptations necessary for sustaining healthy pregnancy. Overall, morphological features were more valuable for discriminating between pregnant and non-pregnant women than HRV features (area under the receiver operating characteristics curve of 0.825 and 0.74, respectively), with the systolic pulse wave deterioration being the most valuable single feature, followed by mean heart rate (HR). Additionally, we stratified the analysis by sleep stages and found that using features calculated only from periods of deep sleep enhanced the differences between the two groups. In conclusion, we postulate that in addition to HRV features, morphological features may also be useful in tracking maternal health and suggest specific features to be included in future research concerning maternal health.</p

The impact of healthy pregnancy on features of heart rate variability and pulse wave morphology derived from wrist-worn photoplethysmography

Due to the association between dysfunctional maternal autonomic regulation and pregnancy complications, tracking non-invasive features of autonomic regulation derived from wrist-worn photoplethysmography (PPG) measurements may allow for the early detection of deteriorations in maternal health. However, even though a plethora of these features-specifically, features describing heart rate variability (HRV) and the morphology of the PPG waveform (morphological features)-exist in the literature, it is unclear which of these may be valuable for tracking maternal health. As an initial step towards clarity, we compute comprehensive sets of HRV and morphological features from nighttime PPG measurements. From these, using logistic regression and stepwise forward feature elimination, we identify the features that best differentiate healthy pregnant women from non-pregnant women, since these likely capture physiological adaptations necessary for sustaining healthy pregnancy. Overall, morphological features were more valuable for discriminating between pregnant and non-pregnant women than HRV features (area under the receiver operating characteristics curve of 0.825 and 0.74, respectively), with the systolic pulse wave deterioration being the most valuable single feature, followed by mean heart rate (HR). Additionally, we stratified the analysis by sleep stages and found that using features calculated only from periods of deep sleep enhanced the differences between the two groups. In conclusion, we postulate that in addition to HRV features, morphological features may also be useful in tracking maternal health and suggest specific features to be included in future research concerning maternal health.</p

Efecto de la capacidad visoespacial en el rendimiento académico de estudiantes de anatomía médica

Visuospatial ability is associated with clinical skills in medical education, as it predicts the academic performance of anatomy students. Objective: To determine whether visuospatial processing generates changes in the teaching of medical anatomy and predicts academic performance in that subject. Methods: 140 students were evaluated at the beginning of the semester and before final exams with the Rey Complex Figure Test (CRFT).&nbsp; Student's t-tests were performed to contrast pre- and post-test differences, Cohen's d to measure effect size, and linear regression to evaluate prediction with final grades. Results: Mean age 20.22 years (SD=1.12), mean grade point average 4.96 (SD=1.20). Seventy percent of the students passed the course. The t-test reports significant differences of TFCR (Memory recall: t=-17.383; p&lt;0.001; Delayed recall: t=-16.547, p&lt;0.001) with a medium effect size (d=0.59 and d=0.56), respectively. The scores obtained in the post-test on the TFCR deferred recall task explained up to 90% of the students' academic performance. Conclusions: The instrument's deferred memory predicted academic performance and anatomy learning improved students' visuospatial function performance.La capacidad visoespacial se asocia con habilidades clínicas en la educación médica, ya que predice el desempeño académico de los estudiantes de anatomía. Objetivo: Determinar si el procesamiento visoespacial genera cambios en la enseñanza de la anatomía médica y predice el desempeño académico en esa asignatura. Método: 140 estudiantes evaluados al inicio de semestre y antes de exámenes finales con el Test de la Figura Compleja de Rey.  Se realizaron análisis t de Student para contrastar las diferencias pre y pos-test, d de Cohen para medir el tamaño de efecto y regresión lineal para evaluar la predicción con las notas finales. Resultados: Edad promedio 20.22 años (DE=1.12), media de calificaciones 4.96 (DE=1.20). El 70% de los estudiantes aprobó la asignatura. La prueba t reporta diferencias significativas del TFCR (Evocación de Memoria: t=-17.383; p&lt;0.001; Evocación diferida: t=-16.547, p&lt;0.001) con un tamaño del efecto mediano (d=0.59 y d=0.56), respectivamente. Las puntuaciones obtenidas en el post-test en la tarea de memoria diferida del TFCR, explicaron hasta en un 90% el desempeño académico de los estudiantes. Conclusiones: La memoria diferida del instrumento predijo el rendimiento académico y el aprendizaje de anatomía mejoró el desempeño en la función visoespacial de los estudiantes