Manejo en vivero de cinco especies arbóreas nativas de regeneración natural para repoblación en el bosque de Huayropungo, Comunidad de Palo Blanco, Provincia del Carchi

El estudio sobre “Manejo en vivero, cinco especies arbóreas nativas producto de la regeneración natural, con fines de reforestación”. Se efectuó con el propósito de conocer el comportamiento de la regeneración natural de las cinco especies en vivero, con fin de dar un aporte en el campo de manejo de los recursos naturales renovables. Se trabajó en base a los siguientes objetivos: Inventariar la Flora Nativa en el área de estudio: Establecer el vivero forestal volante para el manejo de las cinco especies, determinar la adaptación y crecimiento de las especies: Alnus acuminata (Aliso), Myrciantes ropaloides (Arrayán), Miconia theazans (Colca), Oreopanax ecuadorense (Pumamaqui) y Ocotea infrasoveolata (Yalte) Elaborar un Plan de Manejo Comunitario Participativo de las Especies con fines de repoblación en el bosque de montaña de Huayropungo. La regeneración natural se recolectó en el bosque Huayorpungo y el vivero temporal se estableció en los terrenos comunales de Palo Blanco, perteneciente a la provincia del Carchi, cantón Mira parroquia La Concepción a una altitud de 3285 m.s.n.m. temperatura media anual 9,25º C. precipitación media anual 792,5 mm. La investigación tuvo una duración de 12 meses, se aplicó el diseño Irrestricto al azar con diez tratamientos y diez repeticiones. Las variables evaluadas fueron sobrevivencia, circunferencia basal y altura total. Los resultados fueron sometidos al análisis de variancia y Prueba Tuckey al 95%. Finalizado el ensayo la menor sobrevivencia, 90% obtuvieron los tratamientos colca con 35% de sombra y yalte con 35 % de sombra, los demás tratamientos tuvieron el 100%. El mayor crecimiento promedio acumulado en circunferencia basal tuvo el tratamiento arrayán con 35 % de sombra (T3) con 0,81 cm. seguido del aliso con 35 % de sombra (T1) con 0,78 cm. Los de menor crecimiento en circunferencia basal fueron los tratamientos puma maqui con 75 % de sombra (T10) con 0,66 cm. y al final el yalte con 75 % de sombra (T8) con 0,62 cm. El mayor crecimiento en altura total promedio lo tuvieron los tratamientos puma maqui con 35 % de sombra (T9) con 17,7 cm. seguido del yalte con 35 % de sombra (T7) con 17,2 cm. Al final de la investigación el tratamiento que tuvo el menor crecimiento fue colca con 35 % de sombra (T5) con 14, 8 cm. Las bajas precipitaciones, temperaturas y fuerte vientos influyeron en la sobrevivencia de las especies estudiadas. El porcentaje de sombra aplicado a las especies, no influyó en el crecimiento de las plantas. Existió una influencia positiva de las técnicas de manejo a las plantas, en el crecimiento promedio, de la circunferencia basal, como en altura total. Se recomienda aplicar todas las técnicas silviculturales en el manejo de las plantas producto de la regeneración natural, seleccionar las plantas producto de la regeneración natural, que cumplan con las características de vigorosidad, grosor, altura y sanidad, para que su respuesta al manejo silvicultural sea el adecuado

Evolutionary Plasticity of Habenular Asymmetry with a Conserved Efferent Connectivity Pattern

The vertebrate habenulae (Hb) is an evolutionary conserved dorsal diencephalic nuclear complex that relays information from limbic and striatal forebrain regions to the ventral midbrain. One key feature of this bilateral nucleus is the presence of left-right differences in size, cytoarchitecture, connectivity, neurochemistry and/or gene expression. In teleosts, habenular asymmetry has been associated with preferential innervation of left-right habenular efferents into dorso-ventral domains of the midbrain interpeduncular nucleus (IPN). However, the degree of conservation of this trait and its relation to the structural asymmetries of the Hb are currently unknown. To address these questions, we performed the first systematic comparative analysis of structural and connectional asymmetries of the Hb in teleosts. We found striking inter-species variability in the overall shape and cytoarchitecture of the Hb, and in the frequency, strength and to a lesser degree, laterality of habenular volume at the population level. Directional asymmetry of the Hb was either to the left in D. rerio, E. bicolor, O. latipes, P. reticulata, B. splendens, or to the right in F. gardneri females. In contrast, asymmetry was absent in P. scalare and F. gardneri males at the population level, although in these species the Hb displayed volumetric asymmetries at the individual level. Inter-species variability was more pronounced across orders than within a single order, and coexisted with an overall conserved laterotopic representation of left-right habenular efferents into dorso-ventral domains of the IPN. These results suggest that the circuit design involving the Hb of teleosts promotes structural flexibility depending on developmental, cognitive and/or behavioural pressures, without affecting the main midbrain connectivity output, thus unveiling a key conserved role of this connectivity trait in the function of the circuit. We propose that ontogenic plasticity in habenular morphogenesis underlies the observed inter-species variations in habenular asymmetric morphology

A computational framework for testing hypotheses of the minimal mechanical requirements for cell aggregation using early annual killifish embryogenesis as a model

Introduction: Deciphering the biological and physical requirements for the outset of multicellularity is limited to few experimental models. The early embryonic development of annual killifish represents an almost unique opportunity to investigate de novo cellular aggregation in a vertebrate model. As an adaptation to seasonal drought, annual killifish employs a unique developmental pattern in which embryogenesis occurs only after undifferentiated embryonic cells have completed epiboly and dispersed in low density on the egg surface. Therefore, the first stage of embryogenesis requires the congregation of embryonic cells at one pole of the egg to form a single aggregate that later gives rise to the embryo proper. This unique process presents an opportunity to dissect the self-organizing principles involved in early organization of embryonic stem cells. Indeed, the physical and biological processes required to form the aggregate of embryonic cells are currently unknown.Methods: Here, we developed an in silico, agent-based biophysical model that allows testing how cell-specific and environmental properties could determine the aggregation dynamics of early Killifish embryogenesis. In a forward engineering approach, we then proceeded to test two hypotheses for cell aggregation (cell-autonomous and a simple taxis model) as a proof of concept of modeling feasibility. In a first approach (cell autonomous system), we considered how intrinsic biophysical properties of the cells such as motility, polarity, density, and the interplay between cell adhesion and contact inhibition of locomotion drive cell aggregation into self-organized clusters. Second, we included guidance of cell migration through a simple taxis mechanism to resemble the activity of an organizing center found in several developmental models.Results: Our numerical simulations showed that random migration combined with low cell-cell adhesion is sufficient to maintain cells in dispersion and that aggregation can indeed arise spontaneously under a limited set of conditions, but, without environmental guidance, the dynamics and resulting structures do not recapitulate in vivo observations.Discussion: Thus, an environmental guidance cue seems to be required for correct execution of early aggregation in early killifish development. However, the nature of this cue (e.g., chemical or mechanical) can only be determined experimentally. Our model provides a predictive tool that could be used to better characterize the process and, importantly, to design informed experimental strategies

Mice Lacking Thyroid Hormone Receptor β Show Enhanced Apoptosis and Delayed Liver Commitment for Proliferation after Partial Hepatectomy

This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: The role of thyroid hormones and their receptors (TR) during liver regeneration after partial hepatectomy (PH) was studied using genetic and pharmacologic approaches. Roles in liver regeneration have been suggested for T3, but there is no clear evidence distinguishing the contribution of increased amounts of T3 from the modulation by unoccupied TRs. [Methodology/Principal Findings]: Mice lacking TR alpha 1/TR beta or TR beta alone fully regenerated liver mass after PH, but showed delayed commitment to the initial round of hepatocyte proliferation and transient but intense apoptosis at 48h post-PH, affecting similar to 30% of the remaining hepatocytes. Pharmacologically induced hypothyroidism yielded similar results. Loss of TR activity was associated with enhanced nitrosative stress in the liver remnant, due to an increase in the activity of the nitric oxide synthase (NOS) 2 and 3, caused by a transient decrease in the concentration of asymmetric dimethylarginine (ADMA), a potent NOS inhibitor. This decrease in the ADMA levels was due to the presence of a higher activity of dimethylarginineaminohydrolase-1 (DDAH-1) in the regenerating liver of animals lacking TR alpha 1/TR beta or TR beta. DDAH-1 expression and activity was paralleled by the activity of FXR, a transcription factor involved in liver regeneration and up-regulated in the absence of TR. [Conclusions/Significance]: We report that TRs are not required for liver regeneration; however, hypothyroid mice and TR beta-or TR alpha 1/TR beta-deficient mice exhibit a delay in the restoration of liver mass, suggesting a specific role for TRb in liver regeneration. Altered regenerative responses are related with a delay in the expression of cyclins D1 and E, and the occurrence of liver apoptosis in the absence of activated TRb that can be prevented by administration of NOS inhibitors. Taken together, these results indicate that TRb contributes significantly to the rapid initial round of hepatocyte proliferation following PH, and improves the survival of the regenerating liver at later times.This work was supported by grants BFU2008-02161, BFU2007-62402, SAF2007-60511, and SAF2007-60551 from MICINN; S-BIO-0283/2006 from Comunidad de Madrid and FIS-RECAVA RD06/0014/0025 to L.B.; and PI05.0050, PI080070, and the Fundacion Mutua Madrileña to S.H. RECAVA and Ciberehd are funded by the Instituto de Salud Carlos III. R. L-F. is supported by a fellowship from Instituto de Salud Carlos III. The CNIC is supported by the Spanish Ministry of Science and Innovation and the Pro-CNIC Foundation.Peer reviewe

An outbreak of hantavirus pulmonary syndrome, Chile, 1997

Fil: Toro, Jorge. Ministry of Health; Chile.Fil: Vega, Jeanette D. Pan American Health Organization; Chile.Fil: Khan, Ali S. Centers for Disease Control and Prevention; Estados Unidos.Fil: Mills, James N. Centers for Disease Control and Prevention; Estados Unidos.Fil: Padula, Paula. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Terry, William. Centers for Disease Control and Prevention; Estados Unidos.Fil: Yadón, Zaida. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Valderrama, Rosa. Aysen Region XI Health Service; Chile.Fil: Ellis, Barbara A. Centers for Disease Control and Prevention; Estados Unidos.Fil: Pavletic, Carlos. Ministry of Health; Chile.Fil: Cerda, Rodrigo. Pan American Health Organization; Chile.Fil: Zaki, Sherif. Centers for Disease Control and Prevention; Estados Unidos.Fil: Wun-Ju, Shieh. Centers for Disease Control and Prevention; Estados Unidos.Fil: Meyer, Richard. Centers for Disease Control and Prevention; Estados Unidos.Fil: Tapia, Mauricio. Coyhaique Regional Hospital; Chile.Fil: Mansilla, Carlos. Coyhaique Regional Hospital; Chile.Fil: Baro, Michel. Llanchipal Health Services; Chile.Fil: Vergara, Jose A. Llanchipal Health Services; Chile.Fil: Concha, Marisol. Ministry of Health; Chile.Fil: Calderón, Gladys. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas Dr. Julio Maiztegui; Argentina.Fil: Enria, Delia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas Dr. Julio Maiztegui; Argentina.Fil: Peters, C.J. Centers for Disease Control and Prevention; Estados Unidos.Fil: Ksiazek, Thomas G. Centers for Disease Control and Prevention; Estados Unidos.An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area

An outbreak of hantavirus pulmonary syndrome, Chile, 1997

Fil: Toro, Jorge. Ministry of Health; Chile.Fil: Vega, Jeanette D. Pan American Health Organization; Chile.Fil: Khan, Ali S. Centers for Disease Control and Prevention; Estados Unidos.Fil: Mills, James N. Centers for Disease Control and Prevention; Estados Unidos.Fil: Padula, Paula. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Terry, William. Centers for Disease Control and Prevention; Estados Unidos.Fil: Yadón, Zaida. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Valderrama, Rosa. Aysen Region XI Health Service; Chile.Fil: Ellis, Barbara A. Centers for Disease Control and Prevention; Estados Unidos.Fil: Pavletic, Carlos. Ministry of Health; Chile.Fil: Cerda, Rodrigo. Pan American Health Organization; Chile.Fil: Zaki, Sherif. Centers for Disease Control and Prevention; Estados Unidos.Fil: Wun-Ju, Shieh. Centers for Disease Control and Prevention; Estados Unidos.Fil: Meyer, Richard. Centers for Disease Control and Prevention; Estados Unidos.Fil: Tapia, Mauricio. Coyhaique Regional Hospital; Chile.Fil: Mansilla, Carlos. Coyhaique Regional Hospital; Chile.Fil: Baro, Michel. Llanchipal Health Services; Chile.Fil: Vergara, Jose A. Llanchipal Health Services; Chile.Fil: Concha, Marisol. Ministry of Health; Chile.Fil: Calderón, Gladys. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas Dr. Julio Maiztegui; Argentina.Fil: Enria, Delia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas Dr. Julio Maiztegui; Argentina.Fil: Peters, C.J. Centers for Disease Control and Prevention; Estados Unidos.Fil: Ksiazek, Thomas G. Centers for Disease Control and Prevention; Estados Unidos.An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area

Salud de los trabajadores

Actividad física y su relación con los factores de riesgo cardiovascular de carteros chilenosAnálisis de resultados: riesgos psicosociales en el trabajo Suceso-Istas 21 en Cesfam QuellónAusentismo laboral por enfermedades oftalmológicas, Chile 2009Brote de diarreas por norovirus, posterremoto-tsunami, Constitución, Región del MauleCalidad de vida en profesionales de la salud pública chilenaCaracterización del reposo laboral en personal del SSMN durante el primer semestre de 2010Concentración de nicotina en pelo en trabajadores no fumadores expuestos a humo de tabaco ambientalCondiciones de trabajo y bienestar/malestar docente en profesores de enseñanza media de SantiagoDisfunción auditiva inducida por exposición a xilenoErgonomía aplicada al estudio del síndrome de dolor lumbar en el trabajoEstimación de la frecuencia de factores de riesgo cardiovascular en trabajadores de una empresa mineraExposición a plaguicidas inhibidores de la acetilcolinesterasa en Colombia, 2006-2009Factores de riesgo y daños de salud en conductores de una empresa peruana de transporte terrestre, 2009Las consecuencias de la cultura en salud y seguridad ocupacional en una empresa mineraPercepción de cambios en la práctica médica y estrategias de afrontamientoPercepción de la calidad de vida en la Universidad del BiobíoPesos máximos aceptables para tareas de levantamiento manual de carga en población laboral femeninaRiesgo coronario en trabajadores mineros según la función de Framingham adaptada para la población chilenaTrastornos emocionales y riesgo cardiovascular en trabajadores de la salu

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection