1,003 research outputs found

    Left Ventricular Apical Aneurysm in a Cat With Primary Cardiomyopathy

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    Abstract A 13-year-old female Persian cat died suddenly after severe respiratory distress. At necropsy, the changes were compatible with congestive heart failure. The heart was enlarged with a flabby and puckered sac-like aneurysm at the apex of the left ventricle. The apical zone showed a thin muscular wall arising from the free wall of the left ventricle connected to a bulged saccular area through a wide communication. Microscopically, the wall of the aneurysm was composed of fibrous connective tissue with neovascularization and sparse atrophied myocardial cells at the margins. A few isolated cardiomyocytes in the lesion stained positively for desmin, and the inner lining of the aneurysm had immunoreactivity to von Willebrand factor and CD31.Mature fibrous connective tissue was interspersed with degenerated and disorganized cardiomyocytes elsewhere in the myocardium, and many small myocardial arteries were tortuous and thickened. In this case of sudden death, the diagnosis was primary cardiomyopathy, with formation of a left ventricular apical aneurysm within an area of marked myocardial fibrosis and cardiomyocyte atrophy. Keywords left ventricle, apical aneurysm, cats, cardiomyopathy, heart failure, diverticulu

    Bovine diseases causing neurological signs and death in Mexican feedlots

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    Abstract The number of large feedlot operations, similar to that of USA and Canada, has notably increased in Mexico in the last three decades. Clinical and laboratory diagnoses of neurological diseases in feedlot cattle are crucial in Mexico and Central America because of the high incidence of bovine paralytic rabies (BPR). Because of its zoonotic potential, BPR must be promptly diagnosed and differentiated from other bovine neurological diseases such as thrombotic meningoencephalitis (TME), polioencephalomalacia (PEM) and botulism. More recently, BPR and botulism have been diagnosed with increasing frequency in Mexican feedlots. Neither BPR nor botulism has relevant gross lesions, thus post-mortem diagnosis without laboratory support is impossible. Herein, we describe five outbreaks of neurological diseases in Mexican feedlots in which BPR, botulism and PEM were diagnosed either independently or in combination. A diagram illustrating the most conspicuous pathologic findings and ancillary laboratory test required to confirm the diagnoses of these neurological diseases in feedlot cattle is proposed

    sSLAM: Speeded-Up Visual SLAM Mixing Artificial Markers and Temporary Keypoints

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    Environment landmarks are generally employed by visual SLAM (vSLAM) methods in the form of keypoints. However, these landmarks are unstable over time because they belong to areas that tend to change, e.g., shadows or moving objects. To solve this, some other authors have proposed the combination of keypoints and artificial markers distributed in the environment so as to facilitate the tracking process in the long run. Artificial markers are special elements (similar to beacons) that can be permanently placed in the environment to facilitate tracking. In any case, these systems keep a set of keypoints that is not likely to be reused, thus unnecessarily increasing the computing time required for tracking. This paper proposes a novel visual SLAM approach that efficiently combines keypoints and artificial markers, allowing for a substantial reduction in the computing time and memory required without noticeably degrading the tracking accuracy. In the first stage, our system creates a map of the environment using both keypoints and artificial markers, but once the map is created, the keypoints are removed and only the markers are kept. Thus, our map stores only long-lasting features of the environment (i.e., the markers). Then, for localization purposes, our algorithm uses the marker information along with temporary keypoints created just in the time of tracking, which are removed after a while. Since our algorithm keeps only a small subset of recent keypoints, it is faster than the state-of-the-art vSLAM approaches. The experimental results show that our proposed sSLAM compares favorably with ORB-SLAM2, ORB-SLAM3, OpenVSLAM and UcoSLAM in terms of speed, without statistically significant differences in accuracy.This research was funded by the project PID2019-103871GB-I00 of the Spanish Ministry of Economy, Industry and Competitiveness, FEDER, Project 1380047-F UCOFEDER-2021 of Andalusia and by the European Union–NextGeneration EU for requalification of Spanish University System 2021–2023

    sSLAM: Speeded-Up Visual SLAM Mixing Artificial Markers and Temporary Keypoints

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    Environment landmarks are generally employed by visual SLAM (vSLAM) methods in the form of keypoints. However, these landmarks are unstable over time because they belong to areas that tend to change, e.g., shadows or moving objects. To solve this, some other authors have proposed the combination of keypoints and artificial markers distributed in the environment so as to facilitate the tracking process in the long run. Artificial markers are special elements (similar to beacons) that can be permanently placed in the environment to facilitate tracking. In any case, these systems keep a set of keypoints that is not likely to be reused, thus unnecessarily increasing the computing time required for tracking. This paper proposes a novel visual SLAM approach that efficiently combines keypoints and artificial markers, allowing for a substantial reduction in the computing time and memory required without noticeably degrading the tracking accuracy. In the first stage, our system creates a map of the environment using both keypoints and artificial markers, but once the map is created, the keypoints are removed and only the markers are kept. Thus, our map stores only long-lasting features of the environment (i.e., the markers). Then, for localization purposes, our algorithm uses the marker information along with temporary keypoints created just in the time of tracking, which are removed after a while. Since our algorithm keeps only a small subset of recent keypoints, it is faster than the state-of-the-art vSLAM approaches. The experimental results show that our proposed sSLAM compares favorably with ORB-SLAM2, ORB-SLAM3, OpenVSLAM and UcoSLAM in terms of speed, without statistically significant differences in accuracy

    Protocolo de manejo de hernia inguinal en el servicio de cirugía general del hospital Dr. Teodoro Maldonado Carbo, Guayaquil

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    Se propone un protocolo de manejo para la patología herniaria en el Servicio de Cirugía General del Hospital Dr. Teodoro Maldonado Carbo de Guayaquil, cuyo propósito es unificar criterios para el manejo de esta patología tan frecuente en nuestro medio; siendo el objetivo principal disminuir las recurrencias, que fluctúan entre 4 y 6% según las estadísticas mundiales; independientemente de las variables atribuibles al equipo quirúrgico y evaluación exacta de cada caso.Como conclusiones podemos mencionar que la causa principal de recidiva es la tensión en la línea de sutura y que la técnica de Shouldice es la apropiada cuando existe defecto de la pared posterior. Este artículo resume una propuesta para el manejo de esta patología muy frecuente como resultado de la experiencia en este servicio

    Non-Linear Multivariate Dependence between the Mexican Stock Market Index and the Exchange Rate: Efficiency Hypothesis and Political Cycle in Mexico (1994-2012)

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    Este trabajo utiliza una extensión multivariante de la prueba no paramétrica de no linealidad de Hinich (1991) con el objetivo de investigar si existe una relación no lineal entre el índice de la Bolsa Mexicana de Valores (IPC) y el tipo de cambio peso/dólar medida a través de la correlación cruzada y la bicorrelación cruzada en el periodo 1994-2012 durante tres subperíodos de administración presidencial. Este método divide la muestra en ventanas y proporciona información sobre la dependencia no lineal. El principal hallazgo es que no se detectan ventanas de correlación cruzada significativas. No obstante se observan ventanas de tiempo con una bicorrelación cruzada significativa, lo que sugiere una relación no lineal y bidireccional entre las series. Este trabajo concluye que para los tres subperíodos de administración presidencial ambas series mantienen la misma relación no lineal y bidireccional para cualquier cambio en el gobierno con ventanas significativas concentradas al principio del período presidencial sin importar el partido gobernante. Por último es importante destacar que los períodos no lineales bidireccionales se concentraron a mediados del último período presidencial mexicano, lo que indica que los factores financieros externos y económicos globales afectaron esta relación.This paper uses a multivariate extension of the non-parametric nonlinearity test from Hinich (1991) with the objective of investigating whether there is a nonlinear relation between the index of The Mexican Stock Exchange (IPC) and the peso/dollar exchange rate measured through the Cross-correlation and cross-correlation in the period 1994-2012 for three sub-periods of presidential administration. This method divides the sample into windows and provides information on nonlinear dependency. The main finding is that no significant cross-correlation windows are detected. However, time windows are observed with a significant cross bicorrelation, which suggests a non-linear and bidirectional relationship between the series. This paper concludes that for the three sub-periods of presidential administration both series maintain the same nonlinear and bidirectional relation for any change in the government with significant windows concentrated at the beginning of the presidential period regardless of the ruling party. Finally, It is important to note that the non-linear bidirectional periods were concentrated in the middle of the last Mexican presidential period, indicating that global external and economic financial factors affected this relationship.

    The BRISA process as a path for efficient copper recovery from waste PCBs

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    In the present work, a two-stage biohydrometallurgical process for copper extraction from waste PCBs is developed. The main goal of this study is to check whether to separate the chemical leaching of copper with ferric iron from the regeneration of the leaching agent by bacterial oxidation of the ferrous iron is an efficient route for copper recovery from waste PCBs. To test this proposal, large waste PCBs pieces were retained in a stirred tank reactor (STR) in contact with a leaching liquor circulating at a high flow rate between this STR and a bioreactor. The kinetics of leaching of large PCB pieces, when ferric iron is added in excess over the stoichiometric requirements, is limited by the rate of mass transfer of the leaching agent. A heterogeneous kinetic model was proposed to fit the experimental data. It was also found that by increasing the ferric iron concentration the leaching rate was increased. Process separation has proven to be a promising configuration in which the productivity of the bioreactor has fulfilled the leaching agent demand and 90% of copper extraction was achieved in 48 h for large waste PCBs

    Copper recovery from unground printed circuit board by biogenic ferric at high solid/liquid ratio

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    In this work, the recovery of Cu from large waste printed circuit board (PCB) pieces by biogenic ferric sulphate at high solid to liquid ratio was studied. PCB parts were packed in a column and biogenic ferric was constantly recirculated. A high oxidation reduction potential (ORP) decrease was observed in ferric leaching due to ferric ion consumption; this drop caused a slower copper dissolution kinetics. After 25 days, 62.2% of copper was leached from PCBs column. PCBs column was connected to a flooded packed-bed (FPB) bioreactor to study the biological regeneration of ferric ion consumed in chemical reaction. The bioreactor connection enabled working at a constant ORP (700 mV vs. Ag/AgCl) during the whole test time. The improvement of oxidising conditions hugely increased copper dissolution rate, reaching 90% of copper recovery after 25 days. The FPB bioreactor operated continuously without showing inhibition problems and generating a leaching liquor with a high and constant ORP. The novel proposed configuration consists of a chemical reactor, where large PCBs pieces are piled at a high solid load, connected to a FPB bioreactor that regenerates the spent ferric ion enabling the leaching without reagents consumption, is a simple, inexpensive, low energy consumption, eco-friendly and effective system to recover copper from PCBs

    Newborn infants' hair cortisol levels reflect chronic maternal stress during pregnancy

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    Cortisol obtained from hair samples represents a retrospective biomarker of chronic stress experienced by the subject in previous months. Although hair cortisol levels have been used to study the relationship between maternal and neonatal stress levels in primates, this has not yet been performed in humans using a longitudinal design and focusing specifically on this association. Therefore, the objective of this study was to determine whether a relationship existed between maternal psychological stress and hair cortisol levels during pregnancy and postpartum, and neonatal hair cortisol levels. The sample consisted of 80 pregnant women and their 80 newborn infants. We conducted a longitudinal assessment of hair cortisol levels, psychological stress, anxiety, and depression in the three trimesters of pregnancy and postpartum. After childbirth, neonatal hair cortisol levels were also measured. We found that maternal hair cortisol levels in the first trimester negatively predicted neonatal hair cortisol levels. Perceived stress in the third trimester of pregnancy also predicted lower neonatal cortisol, whereas pregnancyspecific stress in the same trimester had a positive relation with neonatal cortisol. Cortisol is essential for embryonic and fetal development; consequently, if fetal synthesis of cortisol is affected by high maternal cortisol levels, such development could be impaired.This work was supported by the I+D Project "PSI2015-63494-P" of the Spanish Ministry of Science and Innovation co-supported by funds/ European Regional Development Fund (ERDF) - a way to build Europe (MIPR). Besides, Mr. Borja Romero-Gonzalez has been awarded with an individual research grant (Spanish Ministry of Economy, Industry and Competitiveness, FPI Program, reference number BES-2016-077619
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