Solving the Uncapacitated Single Allocation p-Hub Median Problem on GPU

A parallel genetic algorithm (GA) implemented on GPU clusters is proposed to solve the Uncapacitated Single Allocation p-Hub Median problem. The GA uses binary and integer encoding and genetic operators adapted to this problem. Our GA is improved by generated initial solution with hubs located at middle nodes. The obtained experimental results are compared with the best known solutions on all benchmarks on instances up to 1000 nodes. Furthermore, we solve our own randomly generated instances up to 6000 nodes. Our approach outperforms most well-known heuristics in terms of solution quality and time execution and it allows hitherto unsolved problems to be solved

An electronic apparatus for early detection of changes in red cell content of blood during anaesthesia

An electronic apparatus was developed for anaesthetists to use to detect changes in red cell concentration during surgery. The mechanism is based on the relationship between the red cell content and the electrical conductivity of blood. In a pilot study of 170 blood samples, a correlation coefficient of 0,9806 was obtained between haematocrit and the instrument readings. To evaluate the instrument's performance in practice, and factors that might influence its readings, a series of 10 cases of aortic surgery were investigated. It is concluded that, although changes in electrolyte concentration, pH and temperature do affect the instrument's readings, these are insignificant compared with those of red cell content, and that the device can be used to indicate a drop in red cell concentration.S Afr Med J 1989; 76: 148-15

Corporate branding’s influence on front-line employee and consumer value co-creation in UK household consumer markets

General managers are presented with an extensive opportunity to innovate and gain market advantage from front-line employees (FLEs) and consumers working together to exchange services and co-create value. To do this, general managers need to understand more about what influences the content and quality of FLE and consumer service exchanges? What predisposes FLEs to commit to service exchange and value co-creation? And what organizational phenomena can general managers use to influence this predisposition? This article presents results from an empirical research study of FLEs employed by a firm that provides installation, servicing and emergency services to domestic households across the United Kingdom. The study reveals the importance of the firm’s corporate brand in its influence upon FLE’s sense of membershipand attachment to a firm (organizational identity) and the consequent effect of this on their predisposition for serviceexchange (organizational commitment), that is, whether FLEs want to remain in their role, because they feel they ought to,want to or they have too much to lose by leaving

A Head-Mounted Camera System Integrates Detailed Behavioral Monitoring with Multichannel Electrophysiology in Freely Moving Mice

Breakthroughs in understanding the neural basis of natural behavior require neural recording and intervention to be paired with high-fidelity multimodal behavioral monitoring. An extensive genetic toolkit for neural circuit dissection, and well-developed neural recording technology, make the mouse a powerful model organism for systems neuroscience. However, most methods for high-bandwidth acquisition of behavioral data in mice rely upon fixed-position cameras and other off-animal devices, complicating the monitoring of animals freely engaged in natural behaviors. Here, we report the development of a lightweight head-mounted camera system combined with head-movement sensors to simultaneously monitor eye position, pupil dilation, whisking, and pinna movements along with head motion in unrestrained, freely behaving mice. The power of the combined technology is demonstrated by observations linking eye position to head orientation; whisking to non-tactile stimulation; and, in electrophysiological experiments, visual cortical activity to volitional head movements

The response of perennial and temporary headwater stream invertebrate communities to hydrological extremes

The headwaters of karst rivers experience considerable hydrological variability, including spates and streambed drying. Extreme summer flooding on the River Lathkill (Derbyshire, UK) provided the opportunity to examine the invertebrate community response to unseasonal spate flows, flow recession and, at temporary sites, streambed drying. Invertebrates were sampled at sites with differing flow permanence regimes during and after the spates. Following streambed drying at temporary sites, dewatered surface sediments were investigated as a refugium for aquatic invertebrates. Experimental rehydration of these dewatered sediments was conducted to promote development of desiccation-tolerant life stages. At perennial sites, spate flows reduced invertebrate abundance and diversity, whilst at temporary sites, flow reactivation facilitated rapid colonisation of the surface channel by a limited number of invertebrate taxa. Following streambed drying, 38 taxa were recorded from the dewatered and rehydrated sediments, with Oligochaeta being the most abundant taxon and Chironomidae (Diptera) the most diverse. Experimental rehydration of dewatered sediments revealed the presence of additional taxa, including Stenophylax sp. (Trichoptera: Limnephilidae) and Nemoura sp. (Plecoptera: Nemouridae). The influence of flow permanence on invertebrate community composition was apparent despite the aseasonal high-magnitude flood events

Widespread forest vertebrate extinctions induced by a mega hydroelectric dam in lowland Amazonia

Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, underconstruction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments

Theory of disk accretion onto supermassive black holes

Accretion onto supermassive black holes produces both the dramatic phenomena associated with active galactic nuclei and the underwhelming displays seen in the Galactic Center and most other nearby galaxies. I review selected aspects of the current theoretical understanding of black hole accretion, emphasizing the role of magnetohydrodynamic turbulence and gravitational instabilities in driving the actual accretion and the importance of the efficacy of cooling in determining the structure and observational appearance of the accretion flow. Ongoing investigations into the dynamics of the plunging region, the origin of variability in the accretion process, and the evolution of warped, twisted, or eccentric disks are summarized.Comment: Mostly introductory review, to appear in "Supermassive black holes in the distant Universe", ed. A.J. Barger, Kluwer Academic Publishers, in pres

Structural Determinants of the Dictyostatin Chemotype for Tubulin Binding Affinity and Antitumor Activity Against Taxane- and Epothilone-Resistant Cancer Cells

A combined biochemical, structural, and cell biology characterization of dictyostatin is described, which enables an improved understanding of the structural determinants responsible for the high-affinity binding of this anticancer agent to the taxane site in microtubules (MTs). The study reveals that this macrolide is highly optimized for MT binding and that only a few of the structural modifications featured in a library of synthetic analogues resulted in small gains in binding affinity. The high efficiency of the dictyostatin chemotype in overcoming various kinds of clinically relevant resistance mechanisms highlights its potential for therapeutic development for the treatment of drug-resistant tumors. A structural explanation is advanced to account for the synergy observed between dictyostatin and taxanes on the basis of their differential effects on the MT lattice. The X-ray crystal structure of a tubulin−dictyostatin complex and additional molecular modeling have allowed the rationalization of the structure−activity relationships for a set of synthetic dictyostatin analogues, including the highly active hybrid 12 with discodermolide. Altogether, the work reported here is anticipated to facilitate the improved design and synthesis of more efficacious dictyostatin analogues and hybrids with other MT-stabilizing agents.We thank Peter T. Northcote for peloruside A, W.-S. Fang for Flutax-2, K. H. Altmann for epothilone D, Dr. Paraskevi Giannakakou (Weill Cornell Medical Center, New York) for the 1A9, PTX10, PTX22, and A8 cell lines, and Prof. Richard Ludueñ a (University of Texas) for the HeLa βIII-transfected cells. We thank Matadero INCOVA (Segovia) for the calf brains for tubulin purification. This work was supported in part by grants BIO2013-42984-R (J.F.D.) and SAF2012-39760-C02-02 (F.G.) from Ministerio de Economia y Competitividad, grant S2010/ ́ BMD-2457 BIPEDD2 from Comunidad Autonoma de Madrid ́ (F.G. and J.F.D.), and the Swiss National Science Foundation grants 310030B_138659 and 31003A_166608 (M.O.S.). The authors acknowledge networking contribution by the COST Action CM1407 “Challenging organic syntheses inspired by naturefrom natural products chemistry to drug discovery” and the COST action CM1470. I.P. thanks the EPSRC and AstraZeneca for funding, Dr. John Leonard (AstraZeneca) for useful discussions, Dr. Stuart Mickel (Novartis) for the provision of chemicals, and the EPSRC UK National Mass Spectrometry Facility at Swansea University for mass spectra

Dystocia in Friesian cows and its effects on postpartum reproductive performance and milk production

A total of 1,243 records for 585 dairy Friesian cows from 1997–2004 were used to study the factors affecting dystocia and its effects on reproductive performance and milk production. The overall incidence of dystocia was 6.9%. The percentage of dystocia decreased with increasing live body weight, age, and parity of cows (P < 0.05); however, it increased with increasing birth weight of calves (P < 0.05). The highest percentage of dystocia was detected in winter season, but the least percentage was in summer season (P < 0.05). The percentage of incidence of dystocia was significantly (P < 0.05) higher with winter feeding compared to summer ration (8.2% vs. 5.1%). The percentage of incidence of dystocia was significantly (P < 0.05) higher with twinning than single calving (15.5% vs. 6.5%), while not significantly affected by the sex of born calves. Incidence of dystocia had adverse effects on reproductive performance and milk yield. The service interval, service period, days open, and calving interval were significantly (P < 0.05) longer in cows afflicted with dystocia compared to normal cows. The conception rate was lower (P < 0.05), but the number of service per conception was higher (P < 0.05) in cows afflicted with dystocia compared to normal cows (60.5% vs. 73.0% and 3.4 vs. 2.7, respectively). Average daily milk yield was lower (P < 0.05) by 1 kg for cows with incidence of dystocia compared to normal cows