Concurrent Segmentation and Localization for Tracking of Surgical Instruments

Real-time instrument tracking is a crucial requirement for various computer-assisted interventions. In order to overcome problems such as specular reflections and motion blur, we propose a novel method that takes advantage of the interdependency between localization and segmentation of the surgical tool. In particular, we reformulate the 2D instrument pose estimation as heatmap regression and thereby enable a concurrent, robust and near real-time regression of both tasks via deep learning. As demonstrated by our experimental results, this modeling leads to a significantly improved performance than directly regressing the tool position and allows our method to outperform the state of the art on a Retinal Microsurgery benchmark and the MICCAI EndoVis Challenge 2015.Comment: I. Laina and N. Rieke contributed equally to this work. Accepted to MICCAI 201

Glomus candidum, a new species of arbuscular mycorrhizal fungi from North American grassland

ENGLISH A new species of arbuscular mycorrhizal fungi, Glomus candidum is described. The species produces spores singly in the soil. Spores are white to very pale yellow, usually globose to subglobose, 87-157 μm diam. Spore wall consists of two adherent layers. The outer layer is hyaline, mucilaginous, and stains very pale pink in Melzer's reagent. This layer can be observed in young spores and often degrades at maturity. The inner layer is hyaline and laminated, but occasionally the innermost group of laminae are pigmented a pale yellow to give the impression of two separated layers. SPANISH Se describe una nueva especie de hongo formador de micorrizas arbusculares, Glomus candidum. La especie produce esporas libres en el suelo. Las esporas son blancas a amarillo muy pálido, usualmente globosas a subglobosas, 87-157 μm de diámetro. La pared de la espora consiste en dos capas adherentes. La capa externa a menudo se degrada con la madurez, es hialina, mucilaginosa, y se tiñe, sólo en las esporas jóvenes, de rosado muy pálido en reactivo de Melzer. La capa interna es hialina y laminada, pero a veces el grupo más interno de láminas aparece pigmentado de amarillo claro dando la impresión de dos capas separadas

Aislamiento de cocaína y benzoilecgonina en muestras de orina por extracciones líquido-líquido y en fase sólida y confirmación por Cromatografía líquida de alta resolución (HPLC)

El consumo ilícito de cocaína se ha incrementado extraordinariamente en los últimos años, por lo que resulta indispensable el desarrollo de metodologías seguras, rápidas y eficientes para su detección. En este trabajo se desarrollo una técnica de HPLC de fase reversa con detector de UV para identificar y cuantificar a la cocaína y la benzoilecgonina, con resultados satisfactorios en los parámetros del control de calidad.Se realizó un estudio de recobrado para el aislamiento de la cocaína y la benzoilecgonina en orina con extracciones liquido liquido y en fase sólida con tres tipos de columnas comerciales (Bond Elut Certify, Extrelut 3 y Supelclean LC-18). Las fracciones obtenidas con la extracción líquido-líquido resultaron muy contaminados, con porcentajes de recobrados bajos (45% y 28% para la cocaína y la benzoilecgonina, respectivamente. En las extracciones en fase sólida para la cocaína resultaron muy eficientes las columnas Supelclean LC-18 (87-102 %) y Extrelut 3 (70-102 %), mientras que para el aislamiento de la benzoilecgonina resultaron más eficiente las columnas Extrelut 3 (86-101 %) y Supelclean LC-18 (73-89%). Las columnas Bond Elut Certify resultaron poco eficientes para el aislamiento de la cocaína (53-79%) y con un recobrado aún mas bajo para su metabolito (2-21% %)

Image Compositing for Segmentation of Surgical Tools Without Manual Annotations

Producing manual, pixel-accurate, image segmentation labels is tedious and time-consuming. This is often a rate-limiting factor when large amounts of labeled images are required, such as for training deep convolutional networks for instrument-background segmentation in surgical scenes. No large datasets comparable to industry standards in the computer vision community are available for this task. To circumvent this problem, we propose to automate the creation of a realistic training dataset by exploiting techniques stemming from special effects and harnessing them to target training performance rather than visual appeal. Foreground data is captured by placing sample surgical instruments over a chroma key (a.k.a. green screen) in a controlled environment, thereby making extraction of the relevant image segment straightforward. Multiple lighting conditions and viewpoints can be captured and introduced in the simulation by moving the instruments and camera and modulating the light source. Background data is captured by collecting videos that do not contain instruments. In the absence of pre-existing instrument-free background videos, minimal labeling effort is required, just to select frames that do not contain surgical instruments from videos of surgical interventions freely available online. We compare different methods to blend instruments over tissue and propose a novel data augmentation approach that takes advantage of the plurality of options. We show that by training a vanilla U-Net on semi-synthetic data only and applying a simple post-processing, we are able to match the results of the same network trained on a publicly available manually labeled real dataset

Planeación estratégica de la empresa Andrews en el simulador de negocios Capstone

En este documento se describen y analizan las estrategias de negocio implementadas en la empresa Andrews dentro del simulador de negocios Capstone. De igual forma, se presentan los resultados en un periodo de simulación de ocho años en los departamentos de mercadotecnia, investigación y desarrollo, finanzas, producción, recursos humanos y calidad

A Mouse Model of Huntington’s Disease Shows Altered Ultrastructure of Transverse Tubules in Skeletal Muscle Fibers

Huntington’s disease (HD) is a fatal and progressive condition with severe debilitating motor defects and muscle weakness. Although classically recognized as a neurodegenerative disorder, there is increasing evidence of cell autonomous toxicity in skeletal muscle. We recently demonstrated that skeletal muscle fibers from the R6/2 model mouse of HD have a decrease in specific membrane capacitance, suggesting a loss of transverse tubule (t-tubule) membrane in R6/2 muscle. A previous report also indicated that Cav1.1 current was reduced in R6/2 skeletal muscle, suggesting defects in excitation–contraction (EC) coupling. Thus, we hypothesized that a loss and/or disruption of the skeletal muscle t-tubule system contributes to changes in EC coupling in R6/2 skeletal muscle. We used live-cell imaging with multiphoton confocal microscopy and transmission electron microscopy to assess the t-tubule architecture in late-stage R6/2 muscle and found no significant differences in the t-tubule system density, regularity, or integrity. However, electron microscopy images revealed that the cross-sectional area of t-tubules at the triad were 25% smaller in R6/2 compared with age-matched control skeletal muscle. Computer simulation revealed that the resulting decrease in the R6/2 t-tubule luminal conductance contributed to, but did not fully explain, the reduced R6/2 membrane capacitance. Analyses of bridging integrator-1 (Bin1), which plays a primary role in t-tubule formation, revealed decreased Bin1 protein levels and aberrant splicing of Bin1 mRNA in R6/2 muscle. Additionally, the distance between the t-tubule and sarcoplasmic reticulum was wider in R6/2 compared with control muscle, which was associated with a decrease in junctophilin 1 and 2 mRNA levels. Altogether, these findings can help explain dysregulated EC coupling and motor impairment in Huntington’s disease

Kochen-Specker Vectors

We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in n-dim Hilbert space, H^n, n>3 to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R^n, on algorithms that single out those diagrams on which algebraic 0-1 states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all 4-dim KS vector systems containing up to 24 vectors were generated and described, all 3-dim vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found.Comment: 19 pages, 6 figures, title changed, introduction thoroughly rewritten, n-dim rotation of KS vectors defined, original Kochen-Specker 192 (117) vector system translated into MMP diagram notation with a new graphical representation, results on Tkadlec's dual diagrams added, several other new results added, journal version: to be published in J. Phys. A, 38 (2005). Web page: http://m3k.grad.hr/pavici

Formación y desarrollo de la competencia del docente como un proceso continuo de profesionalización: Modelo FoDeCD

The need to develop the competencies of educators during their formation is fundamental for their ultimate undertaking of academic responsibilities in a scientific and humanistic perspective. In order to be relevant in the XXI century, these competencies must advance through a continuous process of professionalization of teaching and a personological approach. In keeping with these principles, this paper proposes a model for the development of these competencies to integrate, in a dynamic way, investigation, and the professional, motivational and academic components. The proposed model conceives the teaching-learning process as a process of cooperation between educators and learners that encourages reflection, critical thinking and autonomy.La necesidad de desarrollar las competencias de los docentes en formación es un imperativo para que estos puedan asumir sus funciones académicas desde una posición científico-humanista. Para ser relevante en el siglo XXI, el desarrollo de competencias del docente debe ocurrir en un proceso continuo de profesionalización de la enseñanza y siguiendo un enfoque personológico. A tenor con estos principios, en este artículo se propone un modelo para el desarrollo de las competencias del docente en el que se integran, de forma dinámica, el componente investigativo, laboral, motivacional y académico. El modelo FoDeCD propuesto concibe la enseñanza-aprendizaje como un proceso de cooperación entre educadores y estudiantes que estimula en ellos la reflexión, el pensamiento crítico y la autonomía