7,567 research outputs found
Investigating the relationship between predictability and imbalance in minimisation : a simulation study
Peer reviewedPublisher PD
Aneurysms of the intracranial segment of the ophthalmic artery trunk. case report and systematic literature review
Aneurysms arising from the ophthalmic artery trunk (OAT) are very rare, particularly in the artery's intracranial course. The onset of a subarachnoid hemorrhage (SAH) from a ruptured OAT aneurysm in this segment is extremely rare. We present a case and discuss the anatomy, clinical significance, and therapeutic options for an aneurysm at this site. We also retrospectively analyzed the record of a patient with a ruptured aneurysm of the intracranial segment of the OAT and conducted a comprehensive and systematic review of the PubMed and Scopus databases for literature on this pathology. Only one case report of SAH from an aneurysm of the intracranial segment of the OAT was published in the literature. Only in our case was the intracranial OAT segment aneurysm discovered in the acute phase of SAH. Conventional angiography with three-dimensional acquisition may help detect aneurysms at this level. Detailed knowledge of the anatomy of the OAT is of paramount importance for both surgical and endovascular approaches. Surgical treatment is complex because of difficulties in accessing the orbital region and the risk of optic nerve and vascular injuries. Endovascular treatment, when feasible, could be a good alternative to reduce the risk of loss of vision related to surgical manipulation
Endothelial dysfunction in adolescents and young adults with nonalcoholic liver disease
Nonalcoholic liver disease is a global public health problem that increases cardiovascular morbidity and mortality in these patients. This paper discusses endothelial dysfunction among patients (adolescents and young adults) with nonalcoholic liver disease.
On the one hand, evidence suggests that cardiovascular disease is the leading cause of mortality in patients with advanced nonalcoholic liver disease and that nonalcoholic fatty liver is associated with an increased risk of cardiovascular disease independent of the presence of cardiovascular risk factors and metabolic syndrome components.
On the other hand, nonalcoholic liver disease, especially the non-inflammatory form of nonalcoholic steatohepatitis, may not only be a marker of cardiovascular damage but also a factor involved in its pathogenesis. Such patients are candidates not only for the treatment of liver disease but also for the early treatment of cardiovascular risk factors because many of them, especially those with severe nonalcoholic liver disease, will develop major cardiovascular events and may eventually die of cardiovascular disease before the advanced liver disease occurs
Studying patterns of use of transport modes through data mining - Application to U.S. national household travel survey data set
Data collection activities related to travel require large amounts of financial and human resources to be conducted successfully. When available resources are scarce, the information hidden in these data sets needs to be exploited, both to increase their added value and to gain support among decision makers not to discontinue such efforts. This study assessed the use of a data mining technique, association analysis, to understand better the patterns of mode use from the 2009 U.S. National Household Travel Survey. Only variables related to self-reported levels of use of the different transportation means are considered, along with those useful to the socioeconomic characterization of the respondents. Association rules potentially showed a substitution effect between cars and public transportation, in economic terms but such an effect was not observed between public transportation and nonmotorized modes (e.g., bicycling and walking). This effect was a policy-relevant finding, because transit marketing should be targeted to car drivers rather than to bikers or walkers for real improvement in the environmental performance of any transportation system. Given the competitive advantage of private modes extensively discussed in the literature, modal diversion from car to transit is seldom observed in practice. However, after such a factor was controlled, the results suggest that modal diversion should mainly occur from cars to transit rather than from nonmotorized modes to transi
Three-Dimensional Structure of the Complexin/SNARE Complex
During neurotransmitter release, the neuronal SNARE proteins synaptobrevin/VAMP, syntaxin, and SNAP-25 form a four-helix bundle, the SNARE complex, that pulls the synaptic vesicle and plasma membranes together possibly causing membrane fusion. Complexin binds tightly to the SNARE complex and is essential for efficient Ca2+-evoked neurotransmitter release. A combined X-ray and TROSY-based NMR study now reveals the atomic structure of the complexin/SNARE complex. Complexin binds in an antiparallel Ī±-helical conformation to the groove between the synaptobrevin and syntaxin helices. This interaction stabilizes the interface between these two helices, which bears the repulsive forces between the apposed membranes. These results suggest that complexin stabilizes the fully assembled SNARE complex as a key step that enables the exquisitely high speed of Ca2+-evoked neurotransmitter release
Tracing the Origins and Evolution of Small Planets using Their Orbital Obliquities
We recommend an intensive effort to survey and understand the obliquity
distribution of small close-in extrasolar planets over the coming decade. The
orbital obliquities of exoplanets--i.e., the relative orientation between the
planetary orbit and the stellar rotation--is a key tracer of how planets form
and migrate. While the orbital obliquities of smaller planets are poorly
explored today, a new generation of facilities coming online over the next
decade will make such observations possible en masse. Transit spectroscopic
observations with the extremely large telescopes will enable us to measure the
orbital obliquities of planets as small as around a wide
variety of stars, opening a window into the orbital properties of the most
common types of planets. This effort will directly contribute to understanding
the formation and evolution of planetary systems, a key objective of the
National Academy of Sciences' Exoplanet Science Strategies report.Comment: Submitted to the Astro2020 call for science white papers. 7 pages, 2
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The Paleoindian Component at Charlie Lake Cave (HbRf39), British Columbia
Charlie Lake Cave (HbRf 39) is a stratified site in northeastern British Columbia, Canada, containing a flutedpoint component at the base of the excavated deposits. The small artifact assemblage includes a fluted point, stone bead, core tool, and retouched flake. A diverse associated fauna includes fish, birds, and mammals, indicating a more open environment than exists today. Radiocarbon dates suggest that the artifact assemblage was deposited about 10,500 years ago.
Article Summary by Jonathan C. Driver, May 2015
This was the first major publication about TseāKāwa and it focuses on what for many people was the most exciting find at the site ā a very early occupation of so-called āPaleoindianā people.
There continues to be considerable debate about when the first people came to the Americas. In the 1980ās (and continuing today), the weight of evidence supports a long-held belief that the ancestors of the indigenous peoples of the Americas made their initial migration from somewhere in northeast Asia. However, the timing of this movement, the context in which it occurred, and the date are still contentious. (It is, of course, a simplification to describe this as a single event. There is plenty of evidence for a number of major migrations across the Bering Strait, and it is likely that there was a flow of people and ideas in both directions over thousands of years).
In the 1980ās, as today, virtually all archaeologists agree that āPaleoindianā cultures dating to the end of the last glacial period (about 12,000 BC) indicate a well-established population throughout the Americas by that time, although there is still considerable debate about when the first ancestors of Paleoindians arrived in the Americas.
While the way of life of these peoples must have varied across different environments found in North and South America, the most distinctive Paleoindian artifacts in North America are a kind of stone spear point, known as āfluted pointsā. Fluted points were chipped from fine-grained rocks, such as chert, jasper and obsidian, and generally had a long, lanceolate outline. In order to fit the base of the point into the shaft of the spear, it was thinned by striking off some flakes that ran from the base towards the sharp tip, creating a shallow channel or āfluteā on one or both surfaces of the stone spearpoint.
Fluted points have been found in association with extinct animals, most commonly woolly mammoth and extinct forms of bison, but also with horse and camel, primarily in the central and western half of the USA. Due to different geological and soil conditions in eastern USA, most fluted point sites there do not preserve animal bone. In 1983 when a fluted point was found at TseāKāwa, there was only one site in all of Canada where fluted points had been found in association with organic material that could be radiocarbon dated ā at Debert, in Nova Scotia where charcoal in the soil provided some dates. TseāKāwa was the first site in Canada that produced a fluted point in association with animal bones that had clearly been butchered by people ā in this case an extinct form of bison ā and the first site in Canada in which a fluted point was found at the bottom of a long sequence of later cultural periods. The unique soil conditions at the Tse\u27K\u27wa site have enabled archaeologists to use radio carbon dating on fluted points and animal remains to gain further insight into the lifestyles and timeline of early human occupation of Canada.
Also of significance was the location of TseāKāwa just to the east of the Rockies. Archaeologists had proposed that one route into the Americas during the late ice age was between the Rocky Mountain glaciers to the west and the massive ice sheets that covered Canada to the east ā this so-called āice-free corridorā might have allowed early hunters to move from unglaciated areas of Siberia and Alaska into the vast uninhabited continents to the south of the ice. Although fluted points had been picked up from ploughed fields in BC and Alberta, before the excavations at TseāKāwa none of them had been radiocarbon dated, and so it was difficult to relate them to known dates of glaciers and post-glacial landscapes
Abandoned places, complexes and parts of cities. Regeneration and enhancement of monumental hospitals in the historic centre of Naples
Even before Covid - 19 although in the very center of the old town and historic center of Naples there were abandoned buildings and complexes, uninhabited and unused for decades. The cause is attributed to multiple reasons such as functional obsolescence, failure to adapt to intervening European standards in terms of hospital construction, technological facilities to standards, etc. The health crisis which strongly affected European societies revealed the fragilities of our healthcare systems. In Italy, a large number of COVID-19 patients congested hospitals while the continuity of essential services was interrupted at the expense of other needs. At the same time, the process of abandonment of historic buildings affects different monumental hospitals, such as the āSan Giacomo degli Incurabiliā and the āCarlo Forlaniniā in Rome, or the āGesĆ¹ e Mariaā Hospital, āSan Gennaro dei Poveriā and the āSanta Maria del Popolo degli Incurabiliā in Naples. This paper reports three case studies of Neapolitan historical hospitals regeneration proposals with the goal of strengthening the existing community healthcare system and developing energy efficiency and seismic improvement strategies in the spirit of sustainable development. Leveraging the flexibility of monumental hospitals, the proposed light retrofit interventions restore the historial healthcare functional destination ensuring also the reuse of such an heritage. The current research delineates an approach to the recovery and enhancement for social and cultural purposes of unused and abandoned historical hospitals. This approach can positively affect the quality of life of citizens and the use of health services, while recovering historical cultural heritage buildings
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