943 resultados para 010506 Statistical Mechanics, Physical Combinatorics and Mathematical Aspects of Condensed Matter


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Separate physiological mechanisms which respond to spatial and temporal stimulation have been identified in the visual system. Some pathological conditions may selectively affect these mechanisms, offering a unique opportunity to investigate how psychophysical and electrophysiological tests reflect these visual processes, and thus enhance the use of the tests in clinical diagnosis. Amblyopia and optical blur were studied, representing spatial visual defects of neural and optical origin, respectively. Selective defects of the visual pathways were also studied - optic neuritis which affects the optic nerve, and dementia of the Alzheimer type in which the higher association areas are believed to be affected, but the primary projections spared. Seventy control subjects from 10 to 79 years of age were investigated. This provided material for an additional study of the effect of age on the psychophysical and electrophysiological responses. Spatial processing was measured by visual acuity, the contrast sensitivity function, or spatial modulation transfer function (MTF), and the pattern reversal and pattern onset-offset visual evoked potential (VEP). Temporal, or luminance, processing was measured by the de Lange curve, or temporal MTF, and the flash VEP. The pattern VEP was shown to reflect the integrity of the optic nerve, geniculo striate pathway and primary projections, and was related to high temporal frequency processing. The individual components of the flash VEP differed in their characteristics. The results suggested that the P2 component reflects the function of the higher association areas and is related to low temporal frequency processing, while the Pl component reflects the primary projection areas. The combination of a delayed flash P2 component and a normal latency pattern VEP appears to be specific to dementia of the Alzheimer type and represents an important diagnostic test for this condition.

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Objectives Understanding the impact of the counterion on the properties of an acidic or basic drug may influence the choice of salt form, especially for less potent drugs with a high drug load per unit dose. The aim of this work was to determine the influence of the hydrogen bonding potential of the counterion on the crystal structure of salts of the poorly soluble, poorly compressible, acidic drug gemfibrozil and to correlate these with mechanical properties. Methods Compacts of the parent drug and the salts were used to determine Young's modulus of elasticity using beam bending tests. Crystal structures were determined previously from X-ray powder diffraction data. Key findings The free acid, tert-butylamine, 2-amino-2-methylpropan-1-ol and 2-amino-2-methylpropan-1, 3-diol salts had a common crystal packing motif of infinite hydrogen-bonded chains with cross-linking between pairs of adjacent chains. The tromethamine (trsi) salt, with different mechanical properties, had a two-dimensional sheet-like network of hydrogen bonds, with slip planes, forming a stiffer compact. Conclusions The type of counter ion is important in determining mechanical properties and could be selected to afford slip and plastic deformation. © 2010 Royal Pharmaceutical Society of Great Britain.

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Tanulmányunk a gazdasági versenyképességgel, kiemelten annak nemzetgazdasági szintű vetületével és a sport esetében történő értelmezésével foglakozik. A gazdasági versenyképesség esetén kiemelten kezeljük az IMD és a WEF versenyképességi rangsorait, a sport esetén pedig szétválasztjuk a hivatásos és a szabadidősportot. A hivatásos sport esetén bemutatjuk a sportszakmai versenyképességet indikáló és a sportszakmai versenyképességre hatással lévő gazdasági és társadalmi mutatókat egyaránt. Összehasonlítási csoportot képeztünk, amelyben Magyarország és a környező országok szerepelnek és a komparatív elemzés kiterjed a gazdasági és a sportszakmai versenyképességre, valamint a sportszakmai versenyképességre ható gazdasági és társadalmi tényezőkre egyaránt. A sportszakmai versenyképességet az olimpiai érmek számával és azok pontértékével mérjük, amit az olimpiák teljes történelmére és az elmúlt 20 év különböző szakaszaira egyaránt vizsgálunk, míg a gazdasági és társadalmi tényezőket csak a mondanivalónk szempontjából legrelevánsabb évekre, az új évezredre vizsgálunk. A hivatásos sporttal kapcsolatos versenyképességi kérdésekből azt a következtetést vontuk le, hogy Magyarország történelmi sportszakmai eredményességének fenntartását a jelen gazdasági és társadalmi tényezők nem igazolják, sőt az elmúlt időszak visszaesését támasztják alá és a Londoni olimpián való szereplésünkkel kapcsolatban inkább az összehasonlítási csoporton belüli további visszacsúszást, mintsem az eredmény javulását támogatják. A tanulmányban azt állítjuk, hogy egyéni, vállalati és makrogazdasági versenyképességet is javíthat a szabadidősport. Mikro szinten, majd makrogazdasági szinten elemeztük a szabadidősport hatásait, valamint próbáltunk választ keresni arra a kérdésre, hogy hogyan válhat az egyén, a vállalat és végső célként a gazdaság versenyképesebbé a fizikai aktivitás által. A kevesebb betegség és egészségügyi kiadás, vagy éppen a kedvezőbb várható élettartami mutatók mellett termelékenység-növekedés, a versenyképességi rangsorokban pedig előkelőbb helyezések érhetők el. ______ Our paper tackles the concept of competitiveness in the national level and interprets it also in the field of sport as well. In the economics field we focus on the competitiveness rankings of IMD and WEF and in the sport field we differentiate between professional and leisure sport. In the case of professional sport we introduce the measures of sport competitiveness and its influencing economic and social factors as well. We have made a peer group which contains Hungary and its neighboring countries and the comparative study tackles the sport competitiveness and the influencing economic and social factors as well. We measure sport competitiveness with the Olympic medal count and the medals point value, which is counted in the whole Olympic history, and different phases of the last 20 years. The economic and social factors are compared only in the new millennia as this is the most relevant time frame of this study. From the competitiveness analysis of professional sport we concluded that the maintenance of Hungary’s historical sport successes is not proved by nowadays economic and social factors, however they support the past years decline. These factors also indicate that in London (2012)we would rather slip one more position back in the peer group, than rise again from our ashes. In our opinion leisure sport could enhance the competitiveness of individuals, companies, and economy also. We analysed the effects of leisure sport on the microeconomic and macroeconomic level, and tried to find answer to that question how could be individuals, companies, and economy more competitive through leisure sport. Besides less illness and health care expenditures, longer life expectancy, productivity growth, countries could be well placed in competitiveness’ rankings.

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A közpénzelköltés hatékonyságát hazai viszonylatban az éves közpénzköltés nagyságával és az alkalmazott eljárástípusok, beszerzési tárgyak számával, értékével kapcsolatosan van lehetősége a hivatalos statisztikák elemzése során az érdeklődőnek vizsgálni. A törvény preambulumában található „a közpénzek ésszerű felhasználása átláthatóságának és széles körű nyilvános ellenőrizhetőségének megteremtése, továbbá a közbeszerzések során a verseny tisztaságának biztosítása” célrendszer csak részben érvényesül. A tanulmány arra kíván rávilágítani, hogy a hazai közbeszerzés-kutatás eredményei alapján milyen elképzelés van a GDP közel 5%-án hatékony elköltéséről Magyarországon. Vajon valódi akadálya-e a közbeszerzés a tisztességtelen versenynek, s elősegíti-e a piaci folyamatok érvényesülését annak szabályozása. A szerző válaszai rávilágítanak a közbeszerzési piaci folyamatok, gyengeségek, kevésbé hatékony megnyilvánulások és kritikus vélemények okaira, melyek közvetlen kapcsolatban vannak a közbeszerzés válságos helyzetével, s azonosítják azokat a kritikus pontokat, melyeken érdemes változtatni egy reménybeli hatékonyabb állapot, piaci egyensúlyi helyzet kialakítása érdekében. _______ The analysis of public spending can be based on official statistics showing the figures of annual public spending and the value and number of different procedures and purchased items. However, public procurement spending an annual amount of 1600-1800 billion HUF of public money in an ever changing legal environment, are intended to ensure not only some efficiency in public spending, but to reach several other aims as well. Although the preamble of the public procurement law states, that “a legal environment ought to be created, where the transparency and public accountability of spending public money and fair competition regarding public procurement procedures is ensured”, these requirements are only partially met. This study, based on the results of recent analyses concerning public procurement, wishes to represent our ideas about how to spend efficiently nearly 5% of the Hungarian GDP. Is it really true, that public procurement can be regarded as a genuine means against unfair competition, and can we really foster market processes by regulating public procurement? The author answers highlight the causes of the weaknesses of public procurement procedures, inefficient practices and critical opinions, which are closely connected to the present dire state of public procurement. This study also identifies the crucial elements to be changed in order to achieve a hopefully more efficient state and a preferable market balance.

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We conducted a series of experiments whereby dissolved organic matter (DOM) was leached from various wetland and estuarine plants, namely sawgrass (Cladium jamaicense), spikerush (Eleocharis cellulosa), red mangrove (Rhizophora mangle), cattail (Typha domingensis), periphyton (dry and wet mat), and a seagrass (turtle grass; Thalassia testudinum). All are abundant in the Florida Coastal Everglades (FCE) except for cattail, but this species has a potential to proliferate in this environment. Senescent plant samples were immersed into ultrapure water with and without addition of 0.1% NaN3 (w/ and w/o NaN3, respectively) for 36 days. We replaced the water every 3 days. The amount of dissolved organic carbon (DOC), sugars, and phenols in the leachates were analyzed. The contribution of plant leachates to the ultrafiltered high molecular weight fraction of DOM (>1 kDa; UDOM) in natural waters in the FCE was also investigated. UDOM in plant leachates was obtained by tangential flow ultrafiltration and its carbon and phenolic compound compositions were analyzed using solid state 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy and thermochemolysis in the presence of tetramethylammonium hydroxide (TMAH thermochemolysis), respectively. The maximum yield of DOC leached from plants over the 36-day incubations ranged from 13.0 to 55.2 g C kg−1 dry weight. This amount was lower in w/o NaN3 treatments (more DOC was consumed by microbes than produced) except for periphyton. During the first 2 weeks of the 5 week incubation period, 60–85% of the total amount of DOC was leached, and exponential decay models fit the leaching rates except for periphyton w/o NaN3. Leached DOC (w/ NaN3) contained different concentrations of sugars and phenols depending on the plant types (1.09–7.22 and 0.38–12.4 g C kg−1 dry weight, respectively), and those biomolecules comprised 8–34% and 4–28% of the total DOC, respectively. This result shows that polyphenols that readily leach from senescent plants can be an important source of chromophoric DOM (CDOM) in wetland environments. The O-alkyl C was found to be the major C form (55±9%) of UDOM in plant leachates as determined by 13C CPMAS NMR. The relative abundance of alkyl C and carbonyl C was consistently lower in plant-leached UDOM than that in natural water UDOM in the FCE, which suggests that these constituents increase in relative abundance during diagenetic processing. TMAH thermochemolysis analysis revealed that the phenolic composition was different among the UDOM leached from different plants, and was expected to serve as a source indicator of UDOM in natural water. Polyphenols are, however, very reactive and photosensitive in aquatic environments, and thus may loose their plant-specific molecular characteristics shortly. Our study suggests that variations in vegetative cover across a wetland landscape will affect the quantity and quality of DOM leached into the water, and such differences in DOM characteristics may affect other biogeochemical processes.

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This dissertation consists of three essays on different aspects of water management. The first essay focuses on the sustainability of freshwater use by introducing the notion that altruistic parents do bequeath economic assets for their offspring. Constructing a two-period, over-lapping generational model, an optimal ratio of consumption and pollution for old and young generations in each period is determined. Optimal levels of water consumption and pollution change according to different parameters, such as, altruistic degree, natural recharge rate, and population growth. The second essay concerns water sharing between countries in the case of trans-boundary river basins. The paper recognizes that side payments fail to forge water-sharing agreement among the international community and that downstream countries have weak bargaining power. An interconnected game approach is developed by linking the water allocation issue with other non-water issues such as trade or border security problems, creating symmetry between countries in bargaining power. An interconnected game forces two countries to at least partially cooperate under some circumstances. The third essay introduces the concept of virtual water (VW) into a traditional international trade model in order to estimate water savings for a water scarce country. A two country, two products and two factors trade model is developed, which includes not only consumers and producer's surplus, but also environmental externality of water use. The model shows that VW trade saves water and increases global and local welfare. This study should help policy makers to design appropriate subsidy or tax policy to promote water savings especially in water scarce countries.^

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Integrated interpretation of multi-beam bathymetric, sediment-penetrating acoustic (PARASOUND) and seismic data show a multiple slope failure on the northern European continental margin, north of Spitsbergen. The first slide event occurred during MIS 3 around 30 cal. ka BP and was characterised by highly dynamic and rapid evacuation of ca. 1250 km**3 of sediment from the lower to the upper part of the continental slope. During this event, headwalls up to 1600 m high were created and ca. 1150 km**3 material from hemi-pelagic sediments and from the lower pre-existing trough mouth fan has been entrained and transported into the semi-enclosed Sophia Basin. This megaslide event was followed by a secondary evacuation of material to the Nansen Basin by funnelling of the debris through the channel between Polarstern Seamount and the adjacent continental slope. The main slide debris is overlain by a set of fining-upward sequences as evidence for the associated suspension cloud and following minor failure events. Subsequent adjustment of the eastern headwalls led to failure of rather soft sediments and creation of smaller debris flows that followed the main slide surficial topography. Discharge of the Hinlopen ice stream during the Last Glacial Maximum and the following deglaciation draped the central headwalls and created a fan deposit of glacigenic debris flows.

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This dissertation consists of three essays on different aspects of water management. The first essay focuses on the sustainability of freshwater use by introducing the notion that altruistic parents do bequeath economic assets for their offspring. Constructing a two-period, over-lapping generational model, an optimal ratio of consumption and pollution for old and young generations in each period is determined. Optimal levels of water consumption and pollution change according to different parameters, such as, altruistic degree, natural recharge rate, and population growth. The second essay concerns water sharing between countries in the case of trans-boundary river basins. The paper recognizes that side payments fail to forge water-sharing agreement among the international community and that downstream countries have weak bargaining power. An interconnected game approach is developed by linking the water allocation issue with other non-water issues such as trade or border security problems, creating symmetry between countries in bargaining power. An interconnected game forces two countries to at least partially cooperate under some circumstances. The third essay introduces the concept of virtual water (VW) into a traditional international trade model in order to estimate water savings for a water scarce country. A two country, two products and two factors trade model is developed, which includes not only consumers and producer’s surplus, but also environmental externality of water use. The model shows that VW trade saves water and increases global and local welfare. This study should help policy makers to design appropriate subsidy or tax policy to promote water savings especially in water scarce countries.

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The Autonomous Region of Castilla-La Mancha develops from the approval of the Spanish Constitution a whole executive and legislative branch to implement its policies on environmental protection. The new legislation (Law 9/1999, of 26 May) has pursued the conservation and the integral protection of the natural elements of the territory demanding to new criteria as such the environmental quality of ecosystems or the exceptional landscape. The spread and the declaration of new natural spaces have caused a double geographical and territorial model. First, natural spaces located in rural mountainous areas with depopulation and aging problems. And second, natural spaces situated in areas densely populated

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The purpose of this research is to gain a deeper understanding of how materialistic aspirations are related to distinct aspects of psychological well-being. Research has consistently found a negative relationship between materialistic goals and well-being, but a review of the literature identified that the measures of well- being used in the majority of studies were measures of what Keyes (2002) describes as “subjective well-being” or “hedonic happiness”. Criticisms of these types of measures are that they fixate too much on the momentary experience of pleasure and don’t take into account what is meaningful and or what contributes to long lasting fulfilment. Very little research was found investigating the impact of materialism on “eudaimonic” well-being, which is found through doing what is worthwhile and realising ones potential and has been found to have a longer lasting impact on overall well-being (Huta & Ryan, 2010). To address this gap in the literature, a convenience sample of 113 adult subjects in the UK were recruited through Facebook and asked to respond to the Aspiration Index and the Psychological wellbeing scale. The relative importance placed on extrinsic (materialistic) and intrinsic aspirations was compared to the six dimensions of psychological well-being. In line with previous research, higher importance placed on materialistic aspirations for wealth, status and image were found to be negatively correlated with all aspects of psychological well-being. However, the strongest and only statistically significant negative correlation was between extrinsic aspirations and positive relations with others (r = -.256, p< 0.01). Positive relationships with other people form a central component of many theories of well- being and so this negative relationship may help to explain why materialistic aspirations are so consistently found to be negatively correlated to a variety of measures of well-being. Further research is needed to explore this relationship as no causation could be inferred.