879 research outputs found

    Measuring time perspective in adolescents : can you get the right answer by asking the wrong questions?

    Get PDF
    Time perspective continues to evolve as a psychological construct. The extant literature suggests that higher future orientation and lower present orientation are associated with better developmental outcomes. However, the extant literature also suggests that issues remain with the measurement of the construct. Recently, a 25-item version of the Zimbardo Time Perspective Inventory (ZTPI-25) was suggested for use based on high internal consistency estimates and good discriminant validity of scores in a sample of Italian adolescents. However, the genesis of this scale is uncertain. The present study examined the factorial validity, reliability, and concurrent validity of ZTPI-25 scores in Slovenian, American, and British adolescents. Results revealed satisfactory concurrent validity based on correlations with measures used in the development of the full ZTPI. However, internal consistency and factorial validity of scores were unsatisfactory. The present study questions the use of the ZTPI-25 with adolescents in the context of conceptual and measurement issues more broadly

    What's Decidable about Discrete Linear Dynamical Systems?

    Get PDF
    We survey the state of the art on the algorithmic analysis of discrete linear dynamical systems, and outline a number of research directions

    Impact of Crural Relaxing Incisions, Collis Gastroplasty, and Non–Cross-linked Human Dermal Mesh Crural Reinforcement on Early Hiatal Hernia Recurrence Rates

    Get PDF
    BackgroundHernia recurrence is the leading form of failure after antireflux surgery and may be secondary to unrecognized tension on the crural repair or from a foreshortened esophagus. Mesh reinforcement has proven beneficial for repair of hernias at other sites, but the use of mesh at the hiatus remains controversial. The aim of this study was to evaluate the outcomes of hiatal hernia repair with human dermal mesh reinforcement of the crural closure in combination with tension reduction techniques when necessary.Study DesignWe retrospectively reviewed the records of all patients who had hiatal hernia repair using AlloMax Surgical Graft (Davol), a human dermal biologic mesh. Objective follow-up was with videoesophagram and/or upper endoscopy at 3 months postoperatively and annually.ResultsThere were 82 patients with a median age of 63 years. The majority of operations (85%) were laparoscopic primary repairs of a paraesophageal hernia with a fundoplication. The crura were closed primarily in all patients and reinforced with an AlloMax Surgical Graft. A crural relaxing incision was used in 12% and a Collis gastroplasty in 28% of patients. There was no mesh-related morbidity and no mortality. Median objective follow-up was 5 months, but 15 patients had follow-up at 1 or more years. A recurrent hernia was found in 3 patients (4%).ConclusionsTension-reducing techniques in combination with human biologic mesh crural reinforcement provide excellent early results with no mesh-related complications. Long-term follow-up will define the role of these techniques and this biologic mesh for hiatal hernia repair

    On Reachability Problems for Low-Dimensional Matrix Semigroup

    Get PDF
    We consider the Membership and the Half-Space Reachability problems for matrices in dimensions two and three. Our first main result is that the Membership Problem is decidable for finitely generated sub-semigroups of the Heisenberg group over rational numbers. Furthermore, we prove two decidability results for the Half-Space Reachability Problem. Namely, we show that this problem is decidable for sub-semigroups of GL(2,Z) and of the Heisenberg group over rational numbers

    Toward a fully implantable ecosystem for adaptive neuromodulation in humans: Preliminary experience with the CorTec BrainInterchange device in a canine model

    Get PDF
    This article describes initial work toward an ecosystem for adaptive neuromodulation in humans by documenting the experience of implanting CorTec\u27s BrainInterchange (BIC) device in a beagle canine and using the BCI2000 environment to interact with the BIC device. It begins with laying out the substantial opportunity presented by a useful, easy-to-use, and widely available hardware/software ecosystem in the current landscape of the field of adaptive neuromodulation, and then describes experience with implantation, software integration, and post-surgical validation of recording of brain signals and implant parameters. Initial experience suggests that the hardware capabilities of the BIC device are fully supported by BCI2000, and that the BIC/BCI2000 device can record and process brain signals during free behavior. With further development and validation, the BIC/BCI2000 ecosystem could become an important tool for research into new adaptive neuromodulation protocols in humans

    Electrical Stimulation Modulates High γ Activity and Human Memory Performance.

    Get PDF
    Direct electrical stimulation of the brain has emerged as a powerful treatment for multiple neurological diseases, and as a potential technique to enhance human cognition. Despite its application in a range of brain disorders, it remains unclear how stimulation of discrete brain areas affects memory performance and the underlying electrophysiological activities. Here, we investigated the effect of direct electrical stimulation in four brain regions known to support declarative memory: hippocampus (HP), parahippocampal region (PH) neocortex, prefrontal cortex (PF), and lateral temporal cortex (TC). Intracranial EEG recordings with stimulation were collected from 22 patients during performance of verbal memory tasks. We found that high γ (62-118 Hz) activity induced by word presentation was modulated by electrical stimulation. This modulatory effect was greatest for trials with poor memory encoding. The high γ modulation correlated with the behavioral effect of stimulation in a given brain region: it was negative, i.e., the induced high γ activity was decreased, in the regions where stimulation decreased memory performance, and positive in the lateral TC where memory enhancement was observed. Our results suggest that the effect of electrical stimulation on high γ activity induced by word presentation may be a useful biomarker for mapping memory networks and guiding therapeutic brain stimulation

    2014 Epilepsy Benchmarks Area III: Improve Treatment Options for Controlling Seizures and Epilepsy-Related Conditions Without Side Effects

    Get PDF
    The Epilepsy Benchmark goals in Area III focus on making progress in understanding and controlling seizures and related conditions as well as on developing biomarkers and new therapies that will reduce seizures and improve outcomes for individuals with epilepsy. Area III emphasizes a need to better understand the ways in which seizures start, propagate, and terminate and whether those network processes are common or unique in different forms of epilepsy. The application of that knowledge to improved seizure prediction and detection will also play a role in improving patient outcomes. Animal models of treatment-resistant epilepsy that are aligned with etiologies and clinical features of human epilepsies are especially encouraged as necessary tools to understand mechanisms and test potential therapies. Antiseizure therapies that target (either alone or in combination) novel or multiple seizure mechanisms are prioritized in this section of the Benchmarks. Area III goals also highlight validation of biomarkers of treatment response and safety risk, effective self-management, and patient-centered outcome measures as important areas of emphasis for the next five to ten years

    Liquid State Anomalies for the Stell-Hemmer Core-Softened Potential

    Full text link
    We study the Stell-Hemmer potential using both analytic (exact 1d1d and approximate 2d2d) solutions and numerical 2d2d simulations. We observe in the liquid phase an anomalous decrease in specific volume and isothermal compressibility upon heating, and an anomalous increase in the diffusion coefficient with pressure. We relate the anomalies to the existence of two different local structures in the liquid phase. Our results are consistent with the possibility of a low temperature/high pressure liquid-liquid phase transition.Comment: 4 pages in one gzipped ps file including 11 figures; One RevTex and 11 gzipped eps figure

    A motor association area in the depths of the central sulcus

    Get PDF
    Cells in the precentral gyrus directly send signals to the periphery to generate movement and are principally organized as a topological map of the body. We find that movement-induced electrophysiological responses from depth electrodes extend this map three-dimensionally throughout the gyrus. Unexpectedly, this organization is interrupted by a previously undescribed motor association area in the depths of the midlateral aspect of the central sulcus. This \u27Rolandic motor association\u27 (RMA) area is active during movements of different body parts from both sides of the body and may be important for coordinating complex behaviors
    corecore