1,139 research outputs found
Structural and Stratigraphic Reconstruction of the Whiting Dome Salt Structure in Viosca Knoll-Mississippi Canyon, GOM, Using 3D Seismic Data
Understanding the complexities of salt tectonics is one of the most important factors regarding seismic interpretation of stratigraphy, structure, and geomorphology in the Gulf of Mexico. Evaluating the processes affecting recent mobilization of salt in the shallow, well-imaged section can help provide analogues for older, similar occurrences in the deeper section, thereby providing structural models for the autochthonous salt and its effect on stratigraphy and even potential timing and migration issues of hydrocarbons.
Progradation of delta front and shelf to slope transitional sediments has expulsed and emplaced an allochthonous salt structure (Whiting Dome) in the Viosca Knoll and Mississippi Canyon protraction areas of the Gulf of Mexico. Multiple salt mobilization concepts were employed in order to more specifically define the different stages of this salt structure. In chronologic order, these include Roho (expulsion and initial emplacement), shelf- and slope-loaded salt withdrawal minibasin and detachment (early development), whole cell gravity gliding (late development), and reactive halokinesis influenced diapir creation (current).
A model was developed that describes the interplay between salt tectonics and sedimentation though time based on intensive study of the geologic history of the area, interpretation of 3D seismic data, stratigraphic mapping outboard and above the major salt structures, and conceptual restorations
When is Containment Decidable for Probabilistic Automata?
The containment problem for quantitative automata is the natural quantitative generalisation of the classical language inclusion problem for Boolean automata. We study it for probabilistic automata, where it is known to be undecidable in general. We restrict our study to the class of probabilistic automata with bounded ambiguity. There, we show decidability (subject to Schanuel's conjecture) when one of the automata is assumed to be unambiguous while the other one is allowed to be finitely ambiguous. Furthermore, we show that this is close to the most general decidable fragment of this problem by proving that it is already undecidable if one of the automata is allowed to be linearly ambiguous
Measuring time perspective in adolescents : can you get the right answer by asking the wrong questions?
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
Keeping The Physical Educator “Connected” An Examination Of Comfort Level, Usage And Professional Development Available For Technology Integration In The Curricular Area Of Physical Education
Schools continue to integrate the use of technology, and gymnasiums are not an exception. The purpose of the study was to determine the comfort level of Physical Education teachers integrating technology in the gymnasium, determine types of professional development provided for technology use, and potential barriers associated with technology usage. A survey of 179 practicing Physical Education teachers located in the Midwest completed an online questionnaire. Results indicated Physical Education teachers were comfortable integrating technology but reported inadequate professional develop on technology device implementation. These findings suggest Physical Educators are willing to integrate technology but the professional development and resources available to accomplish this is lacking. Future research should examine PETE program offerings, and additional PD opportunities offered by SHAPE America within the area of technology and Physical Education
Impact of Crural Relaxing Incisions, Collis Gastroplasty, and Non–Cross-linked Human Dermal Mesh Crural Reinforcement on Early Hiatal Hernia Recurrence Rates
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
Editorial: Seizure Forecasting and Detection: Computational Models, Machine Learning, and Translation Into Devices.
The pseudo-reachability problem for diagonalisable linear dynamical systems
We study fundamental reachability problems on pseudo-orbits of linear dynamical systems. Pseudo-orbits can be viewed as a model of computation with limited precision and pseudo-reachability can be thought of as a robust version of classical reachability. Using an approach based on o-minimality of Rexp we prove decidability of the discrete-time pseudo-reachability problem with arbitrary semialgebraic targets for diagonalisable linear dynamical systems. We also show that our method can be used to reduce the continuous-time pseudo-reachability problem to the (classical) time-bounded reachability problem, which is known to be conditionally decidable
Simplified Coalgebraic Trace Equivalence
The analysis of concurrent and reactive systems is based to a large degree on
various notions of process equivalence, ranging, on the so-called
linear-time/branching-time spectrum, from fine-grained equivalences such as
strong bisimilarity to coarse-grained ones such as trace equivalence. The
theory of concurrent systems at large has benefited from developments in
coalgebra, which has enabled uniform definitions and results that provide a
common umbrella for seemingly disparate system types including
non-deterministic, weighted, probabilistic, and game-based systems. In
particular, there has been some success in identifying a generic coalgebraic
theory of bisimulation that matches known definitions in many concrete cases.
The situation is currently somewhat less settled regarding trace equivalence. A
number of coalgebraic approaches to trace equivalence have been proposed, none
of which however cover all cases of interest; notably, all these approaches
depend on explicit termination, which is not always imposed in standard
systems, e.g. LTS. Here, we discuss a joint generalization of these approaches
based on embedding functors modelling various aspects of the system, such as
transition and braching, into a global monad; this approach appears to cover
all cases considered previously and some additional ones, notably standard LTS
and probabilistic labelled transition systems
Electrophysiological Signatures of Spatial Boundaries in the Human Subiculum.
Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. Although studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared the power in three frequency bands (1-4, 4-10, and 30-90 Hz) for target locations near and far from the environmental boundaries. Our results suggest that encoding locations near boundaries elicited stronger theta oscillations than for target locations near the center of the environment and that this difference cannot be explained by variables such as trial length, speed, movement, or performance. These findings provide direct evidence of boundary-dependent neural activity localized in humans to the subiculum, the homolog of the hippocampal subregion in which most boundary cells are found in rodents, and indicate that this system can represent attended locations that rather than the position of one\u27s own body
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