306 research outputs found
The convergence of the Stochastic Gradient Descent (SGD) : a self-contained proof
We give here a proof of the convergence of the Stochastic Gradient Descent
(SGD) in a self-contained manner
Determinants of housing policy in large cities of Ukraine
The article presents housing policy, especially in big cities of Ukraine, in the context of current economic conditions and the increasing number of unresolved problems in the sphere of housing construction. The proposed approach to the analysis of the problems of urban housing policy is based on the Five Dimensions Model (L-F-U-G-T). Determination of principles and ways of solving housing problems in urban areas is used in formulating recommendations for the new housing policy. Verification of the proposed methodological tools has been carried out on the example of the city of Lviv.W artykule została przedstawiona polityka mieszkaniowa, szczególnie w dużych miastach Ukrainy w kontekście obecnych warunków gospodarczych oraz wzrastającej liczby nierozwiązanych problemów w sferze budownictwa mieszkaniowego. Proponowane podejście do analizy problemów miejskiej polityki mieszkaniowej opiera się na modelu przestrzeni pięciowymiarowej (L-F-U-G-T). Określenie zasad i sposobów rozwiązywania problemów mieszkaniowych w strefach miejskich służy sformułowaniu rekomendacji na potrzeby nowej polityki mieszkaniowej. Weryfikacja proponowanych narzędzi metodologicznych została przeprowadzona na przykładzie miasta Lwowa
MENINGOCOCCAL MENINGITIS IN ETHIOPIA 1974.1983 AND STRATEGIES OF CONTROL
ABSTRACT
Ethiopia lies in the eastern part of the African cerebrospinal meningitis belt, but the existence of seasonal epidemic of this dangerous diseases has only been recognized since 1974. In the last decade, epidemic" have occurred every year in at least two region.! in northwestern Ethiopia. This study review" the experience" of three period. During 1974-1976, the region affected were identified and health workers began to appreciate the seriousness of meningitis. There were major epidemic" in 1977 and 1981. More epidemiological studies were done, active and passive "surveillance begun, polyvalent vaccine (A+C) introduced and field treatment of patients proved effective. Much lower case fatality rate" in the 1982 and 1983 outbreak showed the value of these measure. Equally important has been the active participation at all level of government and non government agencies and the communities themselves. Each region is now self sufficient in early detection and management of epidemic". Meningitis control in Ethiopia is a successful example of the primary health care approac
Long term aging effect on the creep strength of the T92 steel
International audienceCreep strength loss of T92 steel after long-term creep exposure at 600°C and 650°C is partially due to a thermal aging of the steel during the first part of the test. In order to quantify the effect of long-term aging on the creep strength loss, creep tests were conducted at 600 and 650°C on T92 steel thermally aged for 10,000h at the same temperature and on as-received T92 steel. Laves phases precipitates were found after thermal aging at 600°C and 650°C with an average equivalent diameter of about 200nm and of about 350nm, respectively. No significant change in hardness and in the matrix substructure as revealed by electron backscatter diffraction occurred during aging. For stresses higher than 170MPa at 600°C and higher than 110MPa at 650°C the time to rupture is four times lower in the aged steels compared to the as-received steel, this is correlated to a secondary creep rate four times higher for the aged specimens compared to that of the as-received steel. Creep tests conducted at 650°C under lower stresses revealed a creep lifetime only twice lower after aging
Oral surgery biomaterials: analyses of Al2O3-treated titanium surfaces tested with fibroblast and osteocyte cell lines
Two different cell lines - MLO-Y4 (murine osteocytes) and 293 (human fibroblasts) - cultured for 48 hours in standard media were used to analyse engineered bio-materials (i.e. Al2O3 shot-peened titanium surfaces). Distribution, density and expression of adhesion molecules (fibronectin and vitronectin) were evaluated under scanning electron microscope (SEM) and confocal microscope (CM) as previously described [1]. The engineered biomaterial surfaces showed under SEM irregular morphology displaying variously-shaped spicules, obtained by shooting different-in-size particles of Al2O3 against the scaffolds of biomaterial. DAPI and fluorochrome-conjugated antibodies were used to highlight nuclei, fibronectin and vitronectin, under CM; cell distribution was analysed after Gold-Palladium sputtering of samples by SEM. Both SEM and CM observations showed better outcome in terms of cell adhesion and distribution in treated titanium surfaces with respect to the untreated ones. The results obtained clearly showed that this kind of surface-treated titanium, used to manufacture devices for dental implantology: i) is very suitable for cell colonization, essential prerequisite for the best osseointegration, and ii) represents an excellent solution for the development of further engineered implants with the target to obtain recovery of dental function stable over time.
Further studies on these Al2O3 shot-peened-titanium surfaces, both in vitro and in vivo, will be needed to obtain accurate definition of better biomaterial outcome, also after additional treatments.
References
[1] Palumbo et al. (2013) Immunocytochemical and structural comparative study of committed versus multipotent stem cells cultured with different biomaterials. Micron 47: 1–9
Satellite downlink scheduling problem: A case study
The synthetic aperture radar (SAR) technology enables satellites to
efficiently acquire high quality images of the Earth surface. This generates
significant communication traffic from the satellite to the ground stations,
and, thus, image downlinking often becomes the bottleneck in the efficiency of
the whole system. In this paper we address the downlink scheduling problem for
Canada's Earth observing SAR satellite, RADARSAT-2. Being an applied problem,
downlink scheduling is characterised with a number of constraints that make it
difficult not only to optimise the schedule but even to produce a feasible
solution. We propose a fast schedule generation procedure that abstracts the
problem specific constraints and provides a simple interface to optimisation
algorithms. By comparing empirically several standard meta-heuristics applied
to the problem, we select the most suitable one and show that it is clearly
superior to the approach currently in use.Comment: 23 page
Epoxy and polyester composites’ characteristics under tribological loading conditions
This research examines the friction and dry wear behaviours of glass fibre-reinforced epoxy
(GFRE) and glass fibre-reinforced polyester (GFRP) composites. Three fibre orientations—parallel
orientation (P–O), anti-parallel orientation (AP–O), and normal orientation (N–O)—and various
sliding distances from 0–15 km were examined. The experiments were carried out using a block-on�ring configuration at room temperature, an applied load of 30 N, and a sliding velocity of 2.8 m/s.
During the sliding, interface temperatures and frictional forces were captured and recorded. Worn
surfaces were examined using scanning electron microscopy to identify the damage. The highest
wear rates for GFRE composites occurred in those with AP–O fibres, while the highest wear rates for
GFRP composites occurred in those with P–O fibres. At longer sliding distances, composites with
P–O and N–O fibres had the lowest wear rates. The highest friction coefficient was observed for
composites with N–O and P–O fibres at higher sliding speeds. The lowest friction coefficient value
(0.25) was for composites with AP–O fibres. GFRP composites with P–O fibres had a higher wear
rate than those with N–O fibres at the maximum speed
Service-oriented system engineering
Service-Oriented System Engineering (SOSE) is one of the emerging research areas that involves a number of research challenges in engineering service-oriented systems, the architecture and computing paradigm as well as the development and management of service-oriented systems. Service-Oriented Computing (SOC) exploits services as the fundamental elements for developing computer-based systems. It has been applied to various areas and promotes fundamental changes to system architecture, especially changing the way software systems are being analyzed, architected, designed, implemented, tested, evaluated, delivered, consumed, maintained and evolved. The innovations of SOC also offer many interesting avenues of research for scientific and industrial communities. In this paper, we present the concepts of the SOSE from the related work. The motivation, opportunities and challenges of the SOSE is highlighted thereafter. In addition to this, a brief overview of accepted papers in our Special Issue on SOSE is presented. Finally we highlight and summarize this paper.N/
Powikłania wymiany stymulatora serca — opis przypadku pacjentki z zakrzepicą żył głębokich kończyny górnej
Deep venous thrombosis of the upper extremity (UEDVT) after pacemaker implantation (PM) is often an underestimated problem, but should be considered as a potential complication, because the number of implanting PM is increasing every year. This case report presents a history of a 57-years old woman with a pacemaker implanted in 1996 due to the 3rd-degree atrioventricular block. The patient was admitted to the hospital for the replacement of the stimulating system. The procedure was complicated by hemorrhage from the pocket of the device and in the postoperative period — the left upper extremity deep vein thrombosis.Zakrzepica żył głębokich kończyny górnej po implantacji stymulatora serca jest często bagatelizowanym problemem, chociaż powinna być brana pod uwagę jako potencjalne powikłanie zabiegu w związku z rosnącą liczbą implantowanych stymulatorów serca każdego roku. W niniejszym tekśćie opisano przypadek 57-letniej pacjentki po wszczepieniu stymulatora serca z powodu bloku przedsionkowo-komorowego III stopnia w 1996 r., która została przyjęta do szpitala w celu wymiany urządzenia. Zabieg był powikłany krwawieniem z loży stymulatora oraz masywną zakrzepicą żył głębokich kończyny górnej lewej w okresie pozabiegowym
Perceptions of oral health adequacy and access in Michigan nursing facilities
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72951/1/j.1741-2358.2007.00202.x.pd
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