Computing relaxations for the three-dimensional stable matching problem with cyclic preferences.

Constraint programming has proven to be a successful framework for determining whether a given instance of the three-dimensional stable matching problem with cyclic preferences (3dsm-cyc) admits a solution. If such an instance is satisfiable, constraint models can even compute its optimal solution for several different objective functions. On the other hand, the only existing output for unsatisfiable 3dsm-cyc instances is a simple declaration of impossibility. In this paper, we explore four ways to adapt constraint models designed for 3dsm-cyc to the maximum relaxation version of the problem, that is, the computation of the smallest part of an instance whose modification leads to satisfiability. We also extend our models to support the presence of costs on elements in the instance, and to return the relaxation with lowest total cost for each of the four types of relaxation. Empirical results reveal that our relaxation models are efficient, as in most cases, they show little overhead compared to the satisfaction version.

Atlas of Nervous System Vascular Malformations: A Systematic Review.

Vascular malformations are frequent in the head and neck region, affecting the nervous system. The wide range of therapeutic approaches demand the correct anatomical, morphological, and functional characterization of these lesions supported by imaging. Using a systematic search protocol in PubMed, Google Scholar, Ebsco, Redalyc, and SciELO, the authors extracted clinical studies, review articles, book chapters, and case reports that provided information about vascular cerebral malformations, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 385,614 articles were grouped; using the inclusion and exclusion criteria, three of the authors independently selected 51 articles about five vascular cerebral malformations: venous malformation, brain capillary telangiectasia, brain cavernous angiomas, arteriovenous malformation, and leptomeningeal angiomatosis as part of Sturge-Weber syndrome. We described the next topics-"definition", "etiology", "pathophysiology", and "treatment"-with a focus on the relationship with the imaging approach. We concluded that the correct anatomical, morphological, and functional characterization of cerebral vascular malformations by means of various imaging studies is highly relevant in determining the therapeutic approach, and that new lines of therapeutic approaches continue to depend on the imaging evaluation of these lesions.

A collection of Constraint Programming models for the three-dimensional stable matching problem with cyclic preferences.

We introduce five constraint models for the 3-dimensional stable matching problem with cyclic preferences and study their relative performances under diverse configurations. While several constraint models have been proposed for variants of the two-dimensional stable matching problem, we are the first to present constraint models for a higher number of dimensions. We show for all five models how to capture two different stability notions, namely weak and strong stability. Additionally, we translate some well-known fairness notions (i.e. sex-equal, minimum regret, egalitarian) into 3-dimensional matchings, and present how to capture them in each model. Our tests cover dozens of problem sizes and four different instance generation methods. We explore two levels of commitment in our models: one where we have an individual variable for each agent (individual commitment), and another one where the determination of a variable involves pairing the three agents at once (group commitment). Our experiments show that the suitability of the commitment depends on the type of stability we are dealing with, and that the choice of the search heuristic can help improve performance. Our experiments not only brought light to the role that learning and restarts can play in solving this kind of problems, but also allowed us to discover that in some cases combining strong and weak stability leads to reduced runtimes for the latter.

Modelo de los clientes que compran productos farmacéuticos / Model of customers buying pharmaceuticals

Entre el año 2010 y 2012 se realizó una investigación doctoral en la cual el autor combinó su experiencia académica en el análisis del comportamiento en la conducta de los consumidores, con su experiencia como consultor e investigador privado de la industria farmacéutica. Demostró que hasta ese momento no existía un modelo o perfil que permitiera conocer al comprador de medicamentos en las farmacias. El autor logró obtener el modelo o perfil analizando las conductas de los compradores de medicamentos que visitan las farmacias, razón por la cual la investigación doctoral se ha considerado pionera a nivel mundial, dado que no existían en ese momento antecedentes en esa específica área del conocimiento, ni del lado de la administración, ni del lado farmacéutico, con lo cual la tesis se ha convertido en el complemento que le faltaba al Marketing farmacéutico, que a la fecha sigue enfocado a la visita diaria de los representantes a hospitales, clínicas, regentes y consultorios particulares. La investigación determinó que la automedicación es un concepto usado por las personas de forma indulgente. El trabajo destaca cómo con la teoría de las expectativas racionales no solo se confirma su aspecto teórico y su ausencia en los compradores de medicinas, lo cual el autor resume en la máxima si racionaliza la compra en términos económicos, no lo hace en términos de salud. la misma teoría puede vincular siete patologías médicas con la automedicación.

Between 2010 and 2012 a doctoral research was carried out in which the author combined his academic experience in the analysis of behavior in consumer behavior, with his experience as a consultant and private investigator of the pharmaceutical industry. He showed that until that moment there was no model or profile that allowed knowing the buyer of medicines in pharmacies. The author managed to obtain the model or profile by analyzing the behavior of drug buyers who visit pharmacies, which is why doctoral research has been considered a pioneer worldwide, given that there were no antecedents in that specific area of knowledge at that time. , neither on the side of the administration, nor on the pharmaceutical side, whereupon the thesis has become the complement that Pharmaceutical Marketing lacked, which to date remains focused on the daily visit of representatives to hospitals, clinics, regents and private offices. The investigation determined that self-medication is a concept used by people in an indulgent way. The work highlights how the theory of rational expectations not only confirms its theoretical aspect and its absence in the buyers of medicines, which the author summarizes in the maximum if it rationalizes the purchase in economic terms, it does not do it in terms of health . The same theory can link seven medical pathologies with self-medication.

Skipped versus consecutive pedicle screw constructs for correction of Lenke 1 curves.

PURPOSE: Thoracic pedicle screws provide superior curve correction to hook and wire constructs in adolescent idiopathic scoliosis, while increasing cost. The number of implants required for best correction and outcome has not yet been determined. METHODS: We retrospectively reviewed pre- and post-operative radiographs and self-reported outcome measures in an age- and curve-matched cohort of 40 patients with Lenke I AIS who underwent selective fusions between T3/4 and L1. Twenty patients were treated with thoracic pedicle screws at every level bilaterally (CON) and 20 patients with screws at every level on the concave side and skipped levels on the convex side of the curve (SKP). All patients had a minimum 2-year follow-up. Radiographs were assessed for coronal and sagittal curvatures, as well as thoracic torsion and vertebral rotation. Health-related quality of life was assessed using the SRS-22 instrument. Instrumentation cost data were collected for each case. RESULTS: Postoperative follow-up averaged 28 months for the CON group and 29 months for the SKP group. No statistically significant differences were found between groups with respect to age and pre- and post-operative radiographic parameters. Both constructs provided acceptable correction of the main thoracic curves (66.9 vs. 66.6 %, CON group and SKP group, respectively; p = 0.92), and spontaneous correction of the proximal thoracic (41.5 vs. 41.1 %; p = 0.92) and thoracolumbar/lumbar curves (54.8 vs. 54.3 %; p = 0.92). No significant difference was found in postoperative SRS-22 scores (96 vs. 94.3; p = 0.34). The CON group cost for instrumentation was significantly higher than the SKP group ($19,500 vs. $13,300; p = 0.002). There was no statistically significant difference in operating room times between groups. CONCLUSION: Both construct types provide excellent coronal correction and sagittal balance, with no significant differences in radiographic findings or clinical outcomes. A significant decrease in cost was found with use of skipped screw constructs.

Unsupervised markerless 3-DOF motion tracking in real time using a single low-budget camera.

Motion tracking is a critical task in many computer vision applications. Existing motion tracking techniques require either a great amount of knowledge on the target object or specific hardware. These requirements discourage the wide spread of commercial applications based on motion tracking. In this paper, we present a novel three degrees of freedom motion tracking system that needs no knowledge on the target object and that only requires a single low-budget camera that can be found installed in most computers and smartphones. Our system estimates, in real time, the three-dimensional position of a nonmodeled unmarked object that may be nonrigid, nonconvex, partially occluded, self-occluded, or motion blurred, given that it is opaque, evenly colored, enough contrasting with the background in each frame, and that it does not rotate. Our system is also able to determine the most relevant object to track in the screen. Our proposal does not impose additional constraints, therefore it allows a market-wide implementation of applications that require the estimation of the three position degrees of freedom of an object.

The morbidity and mortality associated with kidney disease in an HIV-infected cohort in Puerto Rico.

INTRODUCTION: Nephropathy in HIV-infected patients has been associated with progression to AIDS and death. The virus, several comorbid conditions and certain medications may contribute to the development and progression of kidney disease. METHODS: This study analyzed data collected from HIV-infected persons enrolled in a HIV registry in Puerto Rico during January 1998 through September 2006. Demographic factors, clinical manifestations, laboratory findings at enrollment, and antiretroviral therapy (ART) prescriptions were compared between patients with and without kidney disease. Death status and cause of death by December 2006 were also evaluated and compared. RESULTS: The study included 1,283 subjects, 69.0% male, 39.7% injecting drug users, 19.5% hepatitis C infected, 6.5% with diabetes mellitus (DM-2), 11.6% had hypertension (HTN) and 9.0% had kidney disease. Patients with kidney disease had significantly higher (P < .05) HIV viral load mean (273,499 vs. 202,858 copies/mL), CD4 T-cell count < 200 (57.0% vs. 44.4%), underweight (22.9% vs. 10.9%), DM-2 (13.9% vs. 5.8%), HTN (27.8% vs 10.0%) and mortality (15.9 vs 5.7 deaths per 100 years of follow-up) than those without it. Cox proportional hazard analysis showed that patients with kidney disease had a higher mortality risk (2.1) after controlling for age, sex, HIV risk factor, ART prescription in the last year and HIV disease duration. CONCLUSIONS: This study demonstrated a substantial disparity in mortality for Puerto Rican HIV-infected patients with nephropathy. Kidney disease preventive strategies that include aggressive control of HIV-infection and chronic medical conditions, such as hypertension and diabetes, are recommend as an approach to reduce this health disparity.

Nacimiento anómalo de la arteria coronaria izquierda en un tronco común en el seno de Valsalva derecho / Birth of the anomalous left coronary artery in a common trunk within Valsalva right

Se presenta el caso de una paciente de 36 años con antecedente de valvulotomía a los 14 años por estenosis pulmonar congénita, consultó por dolor torácico punzante y disnea de pequeños esfuerzos de 6 meses de evolución. La coronariografía mostró la arteria coronaria izquierda originándose de un tronco común con la arteria coronaria derecha y una lesión obstructiva severa en el origen de la arteria descendente anterior. La paciente fue referida para revascularización quirúrgica.

El enfoque del paciente ictérico / The approach of the jaundice patient

Se presenta una revisión actualizada del metabolismo de la bilirrubina, las causas de la hiperbilirrubenemia, la clasificación implícita de las mismas y el abordaje del paciente con enfermedad hepatobiliar e ictericia según se maneja en nuestro medio en forma óptima de acuerdo a los recursos disponibles. Descriptores: Ictericia, hepatopatía, enfermedad biliar