764 research outputs found

    Self-organized Critical Model Of Biological Evolution

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    A punctuated equilibrium model of biological evolution with relative fitness between different species being the fundamental driving force of evolution is introduced. Mutation is modeled as a fitness updating cellular automaton process where the change in fitness after mutation follows a Gaussian distribution with mean x>0x>0 and standard deviation σ\sigma. Scaling behaviors are observed in our numerical simulation, indicating that the model is self-organized critical. Besides, the numerical experiment suggests that models with different xx and σ\sigma belong to the same universality class. PACS numbers: 87.10.+e, 05.40.+jComment: 8 pages in REVTEX 3.0 with 4 figures (Figures available on request by sending e-mail to [email protected]

    Do You Need Instructions Again? Predicting Wayfinding Instruction Demand

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    The demand for instructions during wayfinding, defined as the frequency of requesting instructions for each decision point, can be considered as an important indicator of the internal cognitive processes during wayfinding. This demand can be a consequence of the mental state of feeling lost, being uncertain, mind wandering, having difficulty following the route, etc. Therefore, it can be of great importance for theoretical cognitive studies on human perception of the environment. From an application perspective, this demand can be used as a measure of the effectiveness of the navigation assistance system. It is therefore worthwhile to be able to predict this demand and also to know what factors trigger it. This paper takes a step in this direction by reporting a successful prediction of instruction demand (accuracy of 78.4%) in a real-world wayfinding experiment with 45 participants, and interpreting the environmental, user, instructional, and gaze-related features that caused it

    Access and non–access site bleeding after percutaneous coronary intervention and risk of subsequent mortality and major adverse cardiovascular events:Systematic review and meta-analysis

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    Background: The prognostic impact of site-specific major bleeding complications after percutaneous coronary intervention (PCI) has yielded conflicting data. The aim of this study is to provide an overview of site-specific major bleeding events in contemporary PCI and study their impact on mortality and major adverse cardiovascular event outcomes. Methods and Results: We conducted a meta-analysis of PCI studies that evaluated site-specific periprocedural bleeding complications and their impact on major adverse cardiovascular events and mortality outcomes. A systematic search of MEDLINE and Embase was conducted to identify relevant studies and random effects meta-analysis was used to estimate the risk of adverse outcomes with site-specific bleeding complications. Twenty-five relevant studies including 2 400 645 patients that underwent PCI were identified. Both non–access site (risk ratio [RR], 4.06; 95% confidence interval [CI], 3.21–5.14) and access site (RR, 1.71; 95% CI, 1.37–2.13) related bleeding complications were independently associated with an increased risk of periprocedural mortality. The prognostic impact of non–access site–related bleeding events on mortality related to the source of anatomic bleeding, for example, gastrointestinal RR, 2.78; 95% CI, 1.25 to 6.18; retroperitoneal RR, 5.87; 95% CI, 1.63 to 21.12; and intracranial RR, 22.71; 95% CI, 12.53 to 41.15. Conclusions: The prognostic impact of bleeding complications after PCI varies according to anatomic source and severity. Non–access site-related bleeding complications have a similar prevalence to those from the access site but are associated with a significantly worse prognosis partly related to the severity of the bleed. Clinicians should minimize the risk of major bleeding complications during PCI through judicious use of bleeding avoidance strategies irrespective of the access site used

    Occult Pneumothoraces in Children With Blunt Torso Trauma

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    Objectives Plain chest x‐ray (CXR) is often the initial screening test to identify pneumothoraces in trauma patients. Computed tomography (CT) scans can identify pneumothoraces not seen on CXR (“occult pneumothoraces”), but the clinical importance of these radiographically occult pneumothoraces in children is not well understood. The objectives of this study were to determine the proportion of occult pneumothoraces in injured children and the rate of treatment with tube thoracostomy among these children. Methods This was a planned substudy from a large prospective multicenter observational cohort study of children younger than 18 years old evaluated in emergency departments (EDs) in the Pediatric Emergency Care Applied Research Network (PECARN) for blunt torso trauma from May 2007 to January 2010. Children with CXRs as part of their trauma evaluations were included for analysis. The faculty radiologist interpretations of the CXRs and any subsequent imaging studies, including CT scans, were reviewed for the absence or presence of pneumothoraces. An “occult pneumothorax” was defined as a pneumothorax that was not identified on CXR, but was subsequently demonstrated on cervical, chest, or abdominal CT scan. Rates of pneumothoraces and placement of tube thoracostomies and rate differences with 95% confidence intervals (CIs) were calculated. Results Of 12,044 enrolled in the parent study, 8,020 (67%) children (median age = 11.3 years, interquartile range [IQR] = 5.3 to 15.2 years) underwent CXRs in the ED, and these children make up the study population. Among these children, 4,276 had abdominal CT scans performed within 24 hours. A total of 372 of 8,020 children (4.6%; 95% CI = 4.2% to 5.1%) had pneumothoraces identified by CXR and/or CT. The CXRs visualized pneumothoraces in 148 patients (1.8%; 95% CI = 1.6% to 2.2%), including one false‐positive pneumothorax, which was identified on CXR, but was not demonstrated on CT. Occult pneumothoraces were present in 224 of 372 (60.2%; 95% CI = 55.0% to 65.2%) children with pneumothoraces. Tube thoracostomies were performed in 85 of 148 (57.4%; 95% CI = 49.0% to 65.5%) children with pneumothoraces on CXR and in 35 of 224 (15.6%; 95% CI = 11.1% to 21.1%) children with occult pneumothoraces (rate difference = –41.8%; 95% CI = –50.8 to –32.3%). Conclusions In pediatric patients with blunt torso trauma, pneumothoraces are uncommon, and most are not identified on the ED CXR. Nearly half of pneumothoraces, and most occult pneumothoraces, are managed without tube thoracostomy. Observation, including in children requiring endotracheal intubation, should be strongly considered during the initial management of children with occult pneumothoraces. Resumen Objetivos La radiografía de tórax simple (RXT) es a menudo la prueba de despistaje inicial para identificar los neumotórax en los pacientes con traumatismo. La tomografía computarizada (TC) puede identificar neumotórax no vistos en la RXT (“neumotórax ocultos”), aunque la importancia clínica de estos neumotórax radiográficamente ocultos en los niños no está muy estudiada. Los objetivos de este estudio fueron determinar la proporción de neumotórax ocultos en los niños accidentados y el porcentaje de tratamiento con tubo de toracostomía en estos niños. Metodología Subestudio diseñado a partir de un gran estudio observacional de cohorte prospectivo multicéntrico de niños menores de 18 años atendidos en los servicios de urgencias (SU) de la Pediatric Emergency Care Applied Research Network (PECARN) que habían sido evaluados por traumatismo torácico cerrado de mayo de 2007 a enero de 2010. Se incluyeron en el análisis los niños en los que la RXT fue parte de la evaluación inicial del traumatismo. Las interpretaciones del radiólogo de las RXT y de cualquier estudio de imagen posterior, incluyendo a TC, se revisaron para la ausencia o presencia de neumotórax. Se definió “neumotórax oculto” como un neumotórax que no fue identificado en la RXT pero que fue posteriormente visualizado en la TC abdominal, torócica o cervical. Se calcularon los porcentajes de neumotórax e inserción de tubo de toracostomía y las diferencias de sus porcentajes con los intervalos de confianza (IC) al 95%. Resultados De los 12.044 incluidos en el estudio principal, se llevo a cabo una RXT en el SU en 8.020 (67%) niños (mediana de edad 11,3 años, rango intercuartílico 5,3 a 15,2), que constituyeron la población de estudio. De estos niños, 4.276 tuvieron una TC realizada en las primeras 24 horas. En 372 de los 8.020 niños (4,6%; IC 95% = 4,2% a 5,1%) se identificó un neumotórax en la RXT y/o la TC. La RXT mostró neumotórax en 148 pacientes (1,8%; IC 95% = 1,6% a 2,2%), incluyendo un falso positivo de neumotórax, que fue identificado en la RXT pero que no fue demostrado en la TC. Los neumotórax ocultos estuvieron presentes en 224 de los 372 niños con neumotórax (60,2%; IC 95% = 55,0% a 65,2%). Se insertaron tubos de toracostomía en 85 de los 148 niños con neumotórax en la RXT (57,4%; IC 95% = 49,0% a 65,5%), y en 35 de los 224 niños con neumotórax oculto (15,6%; IC 95% = 11,1% a 21,1%; diferencia de porcentajes ‐41,8%; IC 95% = ‐50,8 a ‐32,3%). Conclusiones En los pacientes pediátricos con traumatismo torácico cerrado, los neumotórax son poco frecuentes, y la mayoría no son identificados en la RXT en el SU. Casi la mitad de los neumotórax, y la mayoría de los neumotórax ocultos son manejados sin tubo de toracostomía. La observación, incluyendo en los niños que requieren intubación endotraqueal, debería ser especialmente considerada durante el manejo inicial de los niños con neumotórax ocultos.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106913/1/acem12344.pd

    Frequent mutation of receptor protein tyrosine phosphatases provides a mechanism for STAT3 hyperactivation in head and neck cancer

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    The underpinnings of STAT3 hyperphosphorylation resulting in enhanced signaling and cancer progression are incompletely understood. Loss-of-function mutations of enzymes that dephosphorylate STAT3, such as receptor protein tyrosine phosphatases, which are encoded by the PTPR gene family, represent a plausible mechanism of STAT3 hyperactivation. We analyzed whole exome sequencing (n = 374) and reverse-phase protein array data (n = 212) from head and neck squamous cell carcinomas (HNSCCs). PTPR mutations are most common and are associated with significantly increased phospho-STAT3 expression in HNSCC tumors. Expression of receptor-like protein tyrosine phosphatase T (PTPRT) mutant proteins induces STAT3 phosphorylation and cell survival, consistent with a “driver” phenotype. Computational modeling reveals functional consequences of PTPRT mutations on phospho-tyrosine–substrate interactions. A high mutation rate (30%) of PTPRs was found in HNSCC and 14 other solid tumors, suggesting that PTPR alterations, in particular PTPRT mutations, may define a subset of patients where STAT3 pathway inhibitors hold particular promise as effective therapeutic agents.Fil: Lui, Vivian Wai Yan. University of Pittsburgh; Estados UnidosFil: Peyser, Noah D.. University of Pittsburgh; Estados UnidosFil: Ng, Patrick Kwok-Shing. University Of Texas Md Anderson Cancer Center;Fil: Hritz, Jozef. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados Unidos. Masaryk University; República ChecaFil: Zeng, Yan. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Lu, Yiling. University Of Texas Md Anderson Cancer Center;Fil: Li, Hua. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Wang, Lin. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Gilbert, Breean R.. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: General, Ignacio. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Bahar, Ivet. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Ju, Zhenlin. University Of Texas Md Anderson Cancer Center;Fil: Wang, Zhenghe. Case Western Reserve University; Estados UnidosFil: Pendleton, Kelsey P.. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Xiao, Xiao. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Du, Yu. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Vries, John K.. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Hammerman, Peter S.. Harvard Medical School; Estados UnidosFil: Garraway, Levi A.. Harvard Medical School; Estados UnidosFil: Mills, Gordon B.. University Of Texas Md Anderson Cancer Center;Fil: Johnson, Daniel E.. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Grandis, Jennifer R.. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados Unido

    Multi-core FPGA Implementation of ECC with Homogeneous Co-Z Coordinate Representation

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    Elliptic Curve Cryptography (ECC) is gaining popularity in recent years. Having short keys and short signatures in particular makes ECC likely to be adopted in numerous internet-of-things (IoT) devices. It is therefore critical to optimize ECC well for both speed and power consumption. Optimization opportunities exist on several different levels: algorithm, architecture, and/or implementation. We combine optimizations at every level in an efficient multi-core FPGA implementation. The core building block for our implementation is a Montgomery multiplier capable of modular additions and multiplications with an arbitrary prime modulus. The size of the prime modulus can also be changed easily, for which we have implemented and tested up to 528-bits used in the NIST P-521 curve. Based on this building block, we have developed a multi-core architecture that supports multiple parallel modular additions, multiplications, and inverses. Efficient ECC group addition and doubling are then built from this foundation. To support a wide variety of curves and at the same time resist timing/power-based side-channel attacks, our scalar multiplication is implemented using the Co-Z ladder due to Hutter, Joye, and Sierra. This approach also allows us to trade off between speed and power consumption by using a different number of Montgomery cores

    Toward quantifying the increasing role oceanic heat in sea ice loss in the new Arctic

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    Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 96 (2015): 2079–2105, doi:10.1175/BAMS-D-13-00177.1.The loss of Arctic sea ice has emerged as a leading signal of global warming. This, together with acknowledged impacts on other components of the Earth system, has led to the term “the new Arctic.” Global coupled climate models predict that ice loss will continue through the twenty-first century, with implications for governance, economics, security, and global weather. A wide range in model projections reflects the complex, highly coupled interactions between the polar atmosphere, ocean, and cryosphere, including teleconnections to lower latitudes. This paper summarizes our present understanding of how heat reaches the ice base from the original sources—inflows of Atlantic and Pacific Water, river discharge, and summer sensible heat and shortwave radiative fluxes at the ocean/ice surface—and speculates on how such processes may change in the new Arctic. The complexity of the coupled Arctic system, and the logistic and technological challenges of working in the Arctic Ocean, require a coordinated interdisciplinary and international program that will not only improve understanding of this critical component of global climate but will also provide opportunities to develop human resources with the skills required to tackle related problems in complex climate systems. We propose a research strategy with components that include 1) improved mapping of the upper- and middepth Arctic Ocean, 2) enhanced quantification of important process, 3) expanded long-term monitoring at key heat-flux locations, and 4) development of numerical capabilities that focus on parameterization of heat-flux mechanisms and their interactions.2016-06-0

    Truncation of Pik3r1 causes severe insulin resistance uncoupled from obesity and dyslipidaemia by increased energy expenditure.

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    OBJECTIVE: Insulin signalling via phosphoinositide 3-kinase (PI3K) requires PIK3R1-encoded regulatory subunits. C-terminal PIK3R1 mutations cause SHORT syndrome, as well as lipodystrophy and insulin resistance (IR), surprisingly without fatty liver or metabolic dyslipidaemia. We sought to investigate this discordance. METHODS: The human pathogenic Pik3r1 Y657∗ mutation was knocked into mice by homologous recombination. Growth, body composition, bioenergetic and metabolic profiles were investigated on chow and high-fat diet (HFD). We examined adipose and liver histology, and assessed liver responses to fasting and refeeding transcriptomically. RESULTS: Like humans with SHORT syndrome, Pik3r1WT/Y657∗ mice were small with severe IR, and adipose expansion on HFD was markedly reduced. Also as in humans, plasma lipid concentrations were low, and insulin-stimulated hepatic lipogenesis was not increased despite hyperinsulinemia. At odds with lipodystrophy, however, no adipocyte hypertrophy nor adipose inflammation was found. Liver lipogenic gene expression was not significantly altered, and unbiased transcriptomics showed only minor changes, including evidence of reduced endoplasmic reticulum stress in the fed state and diminished Rictor-dependent transcription on fasting. Increased energy expenditure, which was not explained by hyperglycaemia nor intestinal malabsorption, provided an alternative explanation for the uncoupling of IR from dyslipidaemia. CONCLUSIONS: Pik3r1 dysfunction in mice phenocopies the IR and reduced adiposity without lipotoxicity of human SHORT syndrome. Decreased adiposity may not reflect bona fide lipodystrophy, but rather, increased energy expenditure, and we suggest that further study of brown adipose tissue in both humans and mice is warranted
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