RECTANGULAR INVERTIBLE MATRICES

En el presente trabajo, se estudian condiciones de invertibilidad de matrices rectangulares sobre R vía relaciones de congruencia en N, estipulando que anillos tienen número de base invariante. Let n be a positive integer and R a ring with identity element, In this paper, invertibility condition of rectangular matrices over R are studied via congruence relations in N stipulating that rings have invariant basis number

Coral reef degradation at an atoll of the Western Colombian Caribbean

Coral reef decline is an issue of concern around the globe. Remote and uninhabited coral areas are not exempt from facing changes in species composition and functionality due to global drivers. Quitasueño is a remote atoll within the Seaflower Biosphere Reserve, in the Southwestern Caribbean Sea. To evaluate the current status of the coral reefs in Quitasueño we sampled 120 stations through Rapid Ecological Assessment and evaluated four stations through Planar Point Intercept to compare the current percent cover of benthic groups with previous studies in the area. We found pronounced changes in coral and macroalgae covers in time, and great conspicuousness of multiple conditions of deterioration along Quitasueño, including diseases, coral predation, and aggression and invasion of coral colonies by macroalgae and sponges. The reef ecosystem seems to be facing a phase shift, in which the benthic cover previously dominated by hard corals is currently dominated by fleshy macroalgae. It is essential to evaluate the possible drivers of the extent of degradation of Quitasueño to understand the process of deterioration and mitigate the impacts

Descriptive analysis of histological types in women undergoing post mastectomy breast reconstruction

Background: Breast cancer is a pathological entity that widely compromises the life and quality of life of affected women; in addition to the great affectation to the current health services. Therefore, maintaining an accurate and complete cancer registry program is one of the most important factors in implementing national cancer control programs and evaluating the results of screening, diagnosis, and treatment. Among the current limitations in the studies, there is a gap in the study of the population undergoing breast reconstruction. Methods: A retrospective study was carried out at hospital general de México “Dr. Eduardo Licéaga” with the information from the clinical records of the period 2019-2020. Patients undergoing breast reconstruction after mastectomy with histological report were included. Through non-probabilistic sampling, a population of 138 women was formed. For data analysis, frequencies and percentages were calculated for the qualitative variables; while for the quantitative variables, mean and standard deviation were calculated. Results: 138 women who underwent breast reconstruction were included, the mean age was 49.9±10.85 years, the mean BMI was 26.80±4.62 kg/m2, the secondary educational level predominated (34.8%), radiotherapy was applied to 34.1%, reconstruction was late in 75.4%, the most frequent reconstruction technique was TRAM flap (44.2%), the histological type of invasive ductal carcinoma predominated (68.1%). Conclusions: In women undergoing post-mastectomy breast reconstruction, the histological type of invasive ductal carcinoma predominates.

Bacterias benéficas del suelo para proteger y recuperar áreas naturales protegidas

Se les llama Áreas Naturales Protegidas (ANP) donde los ambientes originales no han sido significativamente alterados. En este trabajo se busca aprovechar los recursos biotecnológicos de las ANP con rizobacterias para conservación del área y producción vegetal nativa o alimenticia. El uso de las rizobacterias en plantas de importancia agronómica ha resultado en una alternativa importante a los sistemas de producción con consumo alto de fertilizantes al reducir la contaminación de suelo y agua, sin embargo, trabajos en plantas de importancia forestal o para recuperación y conservación de ANP son muy escasos. En este trabajo se aislaron rizobacterias con capacidad para promoción de crecimiento vegetal. Las rizobacterias aisladas mejoran el porcentaje de germinación de semilla de varios tipos de plantas de importancia forestal, alimenticia y ornamental. Los resultados indican el potencial biotecnológico de las cepas aisladas de suelo de un entorno natural poco perturbado para mejorar la protección y producción vegetal

Motivation gaps and implementation traps:the paradoxical and time-varying effects of family ownership on firm absorptive capacity

We present a theoretical framework of family ownership as a driver of the heterogeneity (between‐firm differences) and variability (within‐firm differences over time) of absorptive capacity (AC). Building on our analysis of the multiple dimensions of family owner influence on firm behavior and the mechanisms that can shape the firm willingness and ability to acquire, assimilate, transform, and exploit external knowledge, we introduce the concepts of motivation gap and implementation gap to explain why, paradoxically, family ownership can cause both upward and downward divergences in AC. Our contingency framework identifies conditions under which the positive and negative effects of family ownership on AC are likely to prevail and adds a temporal perspective suggesting that AC varies depending on the duration of family ownership and ownership succession

Evaluación del impacto social de la Licenciatura en Educación Especial en dos subregiones de Antioquia, Colombia

This research paper presents the results of the evaluation of the social impact of the Special Education undergraduate program, of the University of Antioquia’s Education Faculty, in the East and Southwest subregions of the Antioquia department (Colombia). The main objective was to evaluate the impact of the Program among the graduates and other audiences. The methodology was carried out under a qualitative design, in the evaluative research modality, Social Programs impact type of evaluation. The results of the research were structured under the following categories: Assessment of the quality of the Program, the role of the Special Educator, significant experiences and their impact, and location and working conditions of the graduates. Finally, it poses recommendations to various academic units of the University.Keywords: special education, evaluation, social impact, graduates, occupational performance, assessment.En el presente artículo se dan a conocer los resultados de la evaluación del impacto social del programa de Licenciatura en Educación Especial, Facultad de Educación de la Universidad de Antioquia, en las subregiones de Oriente y Suroeste del departamento de Antioquia (Colombia), cuyo objetivo principal fue evaluar el impacto del Programa desde los egresados y otras audiencias. La metodología se llevó a cabo bajo un diseño cualitativo, modalidad de investigación evaluativa, tipo de evaluación de impacto de programas sociales. Los resultados se estructuraron bajo las categorías: valoración de la calidad del Programa, rol del educador especial, experiencias significativas y su impacto, y ubicación y condiciones laborales de los egresados y egresadas. Finalmente, se plantean recomendaciones a diferentes unidades académicas de la Universidad

Detailed characterization of multiple myeloma circulating tumor cells shows unique phenotypic, cytogenetic, functional, and circadian distribution profile

[EN]Circulating myeloma tumor cells (CTCs) as defined by the presence of peripheral blood (PB) clonal plasma cells (PCs) are a powerful prognostic marker in multiple myeloma (MM). However, the biological features of CTCs and their pathophysiological role in MM remains unexplored. Here, we investigate the phenotypic, cytogenetic, and functional characteristics as well as the circadian distribution of CTCs vs paired bone marrow (BM) clonal PCs from MM patients. Our results show that CTCs typically represent a unique subpopulation of all BM clonal PCs, characterized by downregulation (P < .05) of integrins (CD11a/CD11c/CD29/CD49d/CD49e), adhesion (CD33/CD56/CD117/CD138), and activation molecules (CD28/CD38/CD81). Fluorescence in situ hybridization analysis of fluorescence-activated cell sorter-sorted CTCs also unraveled different cytogenetic profiles vs paired BM clonal PCs. Moreover, CTCs were mostly quiescent and associated with higher clonogenic potential when cocultured with BM stromal cells. Most interestingly, CTCs showed a circadian distribution which fluctuates in a similar pattern to that of CD34(+) cells, and opposite to stromal cell-derived factor 1 plasma levels and corresponding surface expression of CXC chemokine receptor 4 on clonal PCs, suggesting that in MM, CTCs may egress to PB to colonize/metastasize other sites in the BM during the patients' resting period

Consenso mexicano sobre dolor torácico no cardiaco

Introducción: Dolor torácico no cardíaco (DTNC) se define como un síndrome clínico caracte-rizado por dolor retroesternal semejante a la angina de pecho, pero de origen no cardiaco ygenerado por enfermedades esofágicas, osteomusculares, pulmonares o psiquiátricas.Objetivo: Presentar una revisión consensuada basada en evidencias sobre definición, epidemio-logía, fisiopatología, diagnóstico y opciones terapéuticas para pacientes con DTNC.Métodos: Tres coordinadores generales realizaron una revisión bibliográfica de todas las publi-caciones en inglés y espa˜nol sobre el tema y elaboraron 38 enunciados iniciales divididosen tres categorías principales: 1) definiciones, epidemiología y fisiopatología; 2) diagnóstico,y 3) tratamiento. Los enunciados fueron votados (3 rondas) utilizando el sistema Delphi, y losque alcanzaron un acuerdo > 75% fueron considerados y calificados de acuerdo con el sistemaGRADE. Resultados y conclusiones: El consenso final incluyó 29 enunciados Todo paciente que debutacon dolor torácico debe ser inicialmente evaluado por un cardiólogo. La causa más común deDTNC es la enfermedad por reflujo gastroesofágico (ERGE). Como abordaje inicial, si no existensíntomas de alarma, se puede dar una prueba terapéutica con inhibidor de bomba de pro-tones (IBP) por 2-4 semanas. Si hay disfagia o síntomas de alarma, se recomienda hacer unaendoscopia. La manometría de alta resolución es el mejor método para descartar trastornosmotores espásticos y acalasia. La pHmetría ayuda a demostrar exposición esofágica anormal alácido. El tratamiento debe ser dirigido al mecanismo fisiopatológico, y puede incluir IBP, neu-romoduladores y/o relajantes de músculo liso, intervención psicológica y/o terapia cognitiva,y ocasionalmente cirugía o terapia endoscópica. ABSTRACT Introduction: Non-cardiac chest pain is defined as a clinical syndrome characterized by retros-ternal pain similar to that of angina pectoris, but of non-cardiac origin and produced byesophageal, musculoskeletal, pulmonary, or psychiatric diseases.Aim: To present a consensus review based on evidence regarding the definition, epidemiology,pathophysiology, and diagnosis of non-cardiac chest pain, as well as the therapeutic options forthose patients. Methods: Three general coordinators carried out a literature review of all articles published inEnglish and Spanish on the theme and formulated 38 initial statements, dividing them into 3 maincategories: (i) definitions, epidemiology, and pathophysiology; (ii) diagnosis, and (iii) treatment.The statements underwent 3 rounds of voting, utilizing the Delphi system. The final statementswere those that reached > 75% agreement, and they were rated utilizing the GRADE system.Results and conclusions: The final consensus included 29 statements. All patients presentingwith chest pain should initially be evaluated by a cardiologist. The most common cause ofnon-cardiac chest pain is gastroesophageal reflux disease. If there are no alarm symptoms, the initial approach should be a therapeutic trial with a proton pump inhibitor for 2-4 weeks. Ifdysphagia or alarm symptoms are present, endoscopy is recommended. High-resolution mano-metry is the best method for ruling out spastic motor disorders and achalasia and pH monitoringaids in demonstrating abnormal esophageal acid exposure. Treatment should be directed at thepathophysiologic mechanism. It can include proton pump inhibitors, neuromodulators and/orsmooth muscle relaxants, psychologic intervention and/or cognitive therapy, and occasionallysurgery or endoscopic therapy