Compact Brillouin devices through hybrid integration on Silicon

A range of unique capabilities in optical and microwave signal processing have been demonstrated using stimulated Brillouin scattering. The desire to harness Brillouin scattering in mass manufacturable integrated circuits has led to a focus on silicon-based material platforms. Remarkable progress in silicon-based Brillouin waveguides has been made, but results have been hindered by nonlinear losses present at telecommunications wavelengths. Here, we report a new approach to surpass this issue through the integration of a high Brillouin gain material, As2S3, onto a silicon chip. We fabricated a compact spiral device, within a silicon circuit, achieving an order of magnitude improvement in Brillouin amplification. To establish the flexibility of this approach, we fabricated a ring resonator with free spectral range precisely matched to the Brillouin shift, enabling the first demonstration of Brillouin lasing in a silicon integrated circuit. Combining active photonic components with the SBS devices shown here will enable the creation of compact, mass manufacturable optical circuits with enhanced functionality

Large Fermi-energy shift and suppression of trivial surface states in NbP Weyl semimetal thin films

Weyl semimetals, a class of 3D topological materials, exhibit a unique electronic structure featuring linear band crossings and disjoint surface states (Fermi-arcs). While first demonstrations of topologically driven phenomena have been realized in bulk crystals, efficient routes to control the electronic structure have remained largely unexplored. Here, a dramatic modification of the electronic structure in epitaxially grown NbP Weyl semimetal thin films is reported, using in situ surface engineering and chemical doping strategies that do not alter the NbP lattice structure and symmetry, retaining its topological nature. Through the preparation of a dangling-bond-free, P-terminated surface which manifests in a surface reconstruction, all the well-known trivial surface states of NbP are fully suppressed, resulting in a purely topological Fermi-arc dispersion. In addition, a substantial Fermi-energy shift from -0.2 to 0.3 eV across the Weyl points is achieved by surface chemical doping, unlocking access to the hitherto unexplored n-type region of the Weyl spectrum. These findings constitute a milestone toward surface-state and Fermi-level engineering of topological bands in Weyl semimetals, and, while there are still challenges in minimizing doping-driven disorder and grain boundary density in the films, they do represent a major advance to realize device heterostructures based on Weyl physics

Seroprevalence of Neospora caninum infection in cattle from Pereira, Colombia

There are over 25.6 million cattle heads in Colombia being the fourth-highest herd in Latin America. This study aimed to describe the seroprevalence of Neospora caninum in cattle from 25 rural farms at Pereira municipality, Risaralda Department, which has a total bovine population of 43,508 animals. A cross-sectional observational study was performed in beef and dairy herds during 2017–2018. A total of 325 animals in 25 herds, with 13 animals per herd, were sampled. A commercial competitive ELISA (cELISA) kit was used to detect N. caninum antibodies. Associated risk factors were analyzed in two different levels: individual animals and herds. For all the independent variables, chi-square (χ2) and Fisher tests were used to assess associations and significance. The overall estimated seropositivity was 20.6% (95%CI 16.2%–25.0%). The seroprevalence by herds was 92.0% ranging from 0.0% to 46.2%. Noteworthy, beef herds had significantly (p = 0.0107) higher seropositivity (50% of them above 35% of seropositivity) compared with those for milk purposes (4.8%) (OR = 20.0; 95%CI 1.2–331.0). Other risk factors were not significantly (p ≥ 0.05) associated with N. caninum seropositivity. Bovine neosporosis may be associated with abortions in both beef and dairy Colombian farms. More studies about the epidemiology, associated factors and consequences, as well as on tools for better diagnosis of bovine abortion, including histopathology and other ancillary tests, should be performed.Fil: Idarraga Bedoya, Samuel E.. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Álvarez Chica, Jaime. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Bonilla Aldana, D. Katterine. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; ColombiaFil: Moore, Dadin Prando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Rodríguez Morales, Alfonso J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; Colombi

Realization of epitaxial NbP and TaP Weyl semimetal thin films

Weyl semimetals (WSMs) exhibit an electronic structure governed by linear band dispersions and degenerate (Weyl) points that lead to exotic physical phenomena. While WSMs were established in bulk monopnictide compounds several years ago, the growth of thin films remains a challenge. Here, we report the bottom-up synthesis of single-crystalline NbP and TaP thin films, 9 to 70 nm thick, by means of molecular beam epitaxy. The as-grown epitaxial films feature a phosphorus-rich stoichiometry, a tensile-strained unit cell, and a homogeneous surface termination, unlike their bulk crystal counterparts. These properties result in an electronic structure governed by topological surface states as directly observed using in situ momentum photoemission microscopy, along with a Fermi-level shift of -0.2 eV with respect to the intrinsic chemical potential. Although the Fermi energy of the as-grown samples is still far from the Weyl points, carrier mobilities close to 103 cm2/(V s) have been measured at room temperature in patterned Hall-bar devices. The ability to grow thin films of Weyl semimetals that can be tailored by doping or strain, is an important step toward the fabrication of functional WSM-based devices and heterostructures

Conditions of work and dermatitis in workers exposed to chemical risks by cement

This research was carried out in order to identify the working conditions in workers exposed to cement in a cement factory in the city of Cartagena. Through different tools it was possible to carry out the diagnosis of the working conditions and to identify the hazards to which the workers of the company are exposed when being in direct contact with the cement; in this way it was possible to know that the dermatitis that were manifesting the workers has its direct relation with this chemical and therefore to be able to establish those measures tending to ensure the complete state of health of the workers. The type of research carried out is descriptive-qualitative, the applied methodology used as a closed questions survey tool, it was obtained as a result that 70% of the respondents did not use personal protection elements when handling cement, so can say that there is a considerable number of people exposed, which increases the likelihood that they may suffer contact dermatitis, through this the different preventive measures for working and health conditions among the employees of the cement company were raised

Ciclo de vida, hábitos y morfometría de Metamasius hemipterus olivier y Rhynchophorus palmarum L. (Coleoptera: Curculionidae) en caña de azúcar (Saccharum officinarum L.).

Palma-Elaeis guineensi

Factibilidad agronómica y entomológica de la siembra intercalada caña de azúcar (Saccharum officinarum L.) y fríjol (Phaseolus vulgaris L.).

Fríjol-Phaseolus vulgarisCaña de azúcar-Saccharum officinaru

Technical and clinical evaluation of a closed loop TIVA system with SEDLineTM spectral density monitoring: Multicentric prospective cohort study

Introduction: Closed loop total intravenous anesthesia is a technique in which the patient’s hemodynamic and anesthetic depth variables are monitored, and based on this information, a computer controls the infusion rate of drugs to keep them within pre-established clinical parameters. Objective: To describe the technical and clinical performance of a closed loop system for total intravenous anesthesia with propofol and remifentanil, using the SEDLineTM monitor Design: Multicentric prospective cohort study Setting: Surgery room Patients: ASA I-II undergoing elective surgery Measurements: The authors designed a closed loop system that implements a control algorithm based on anesthetic depth monitoring and the Patient State Index (PSITM) of the SEDLine monitor for propofol, and on hemodynamic variables for remifentanil. The measurement of clinical performance was made based on the percentage of PSITM maintenance time in the range 20–50. Precision analysis was evaluated by measuring median performance error (MDPE) can be defined as the median difference between actual and desired values, which refers to the degree of precision in which the controller is able to maintain the control variable within the objective set by the anesthesiologist; it represents the direction (over-prediction or underprediction) of performance error (PE) rather than size of errors, which is represented by MDAPE, median absolute percentage error, Wobble index, which is used for measuring the intrasubject variability in performance error. Results: Data were obtained from 93 patients in three healthcare centers. The percentage of PSITM maintenance time in the 20–50 range was 92% (80.7–97.0). MDPE was 10.7 (− 11.0–18.0), MDAPE 21.0 (14.2– 26.8) and wobble 10.7 (7.0–16.9). No adverse surgical or anesthetic events were found