1,731 research outputs found
Random wave loads on a long detached breakwater considering diffraction
Battjes (1982) found the loads of short-crested random waves on a long structure decrease with the structure length and also with the obliqueness of wave incidence. These decreases come from the spatial phase difference along the structure. Lee et al. (2010) found that obliquely incident random waves in a nearshore area become directionally asymmetric due to refraction. They also found the asymmetry becomes more significant in shallower waters. Recently, Jung et al. (2011) studied random wave loads on a long structure considering diffraction and directional asymmetry. In this study, we further study random wave loads on a detached breakwater considering diffraction of waves which propagate at both ends of the breakwater. We also consider directional asymmetry. The structure may be placed along the bottom contours in order to protect on-shore incoming waves. In that case, refraction induced random waves may become asymmetric, i.e., on-shore components are more dominant than along-shore ones. Therefore, directional obliqueness on the structure becomes less and thus the wave loads decrease in less degree than the symmetric waves. When waves are obliquely incident on a long structure, the diffract ing waves give forces on the lee side of the structure. The diffracting wave has a spatial phase variation along the lee side which is different from that the obliquely incident wave has on the front side. Thus, the wave loads decrease with the existence of diffract ing waves and also the phase difference between the incident and diffracting waves
"5 Days in August" – How London Local Authorities used Twitter during the 2011 riots
© IFIP International Federation for Information Processing 2012This study examines effects of microblogging communications during emergency events based on the case of the summer 2011 riots in London. During five days in August 2011, parts of London and other major cities in England suffered from extensive public disorders, violence and even loss of human lives. We collected and analysed the tweets posted by the official accounts maintained by 28 London local government authorities. Those authorities used Twitter for a variety of purposes such as preventing rumours, providing official information, promoting legal actions against offenders and organising post-riot community engagement activities. The study shows how the immediacy and communicative power of microblogging can have a significant effect at the response and recovery stages of emergency events
Blowup Criterion for the Compressible Flows with Vacuum States
We prove that the maximum norm of the deformation tensor of velocity
gradients controls the possible breakdown of smooth(strong) solutions for the
3-dimensional compressible Navier-Stokes equations, which will happen, for
example, if the initial density is compactly supported \cite{X1}. More
precisely, if a solution of the compressible Navier-Stokes equations is
initially regular and loses its regularity at some later time, then the loss of
regularity implies the growth without bound of the deformation tensor as the
critical time approaches. Our result is the same as Ponce's criterion for
3-dimensional incompressible Euler equations (\cite{po}). Moreover, our method
can be generalized to the full Compressible Navier-Stokes system which improve
the previous results. In addition, initial vacuum states are allowed in our
cases.Comment: 17 page
Dynamic assembly of Hda and the sliding clamp in the regulation of replication licensing
Regulatory inactivation of DnaA (RIDA) is one of the major regulatory mechanisms of prokaryotic replication licensing. In RIDA, the Hda-sliding clamp complex loaded onto DNA directly interacts with adenosine triphosphate (ATP)-bound DnaA and stimulates the hydrolysis of ATP to inactivate DnaA. A prediction is that the activity of Hda is tightly controlled to ensure that replication initiation occurs only once per cell cycle. Here, we determined the crystal structure of the Hda-�� clamp complex. This complex contains two pairs of Hda dimers sandwiched between two �� clamp rings to form an octamer that is stabilized by three discrete interfaces. Two separate surfaces of Hda make contact with the �� clamp, which is essential for Hda function in RIDA. The third interface between Hda monomers occludes the active site arginine finger, blocking its access to DnaA. Taken together, our structural and mutational analyses of the Hda-�� clamp complex indicate that the interaction of the �� clamp with Hda controls the ability of Hda to interact with DnaA. In the octameric Hda-�� clamp complex, the inability of Hda to interact with DnaA is a novel mechanism that may regulate Hda function. ? The Author(s) 2017.113Ysciescopu
Influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs
Participants in the pig production industry focus on feed and feed additives to improve growth performance and meat quality of pigs. Consequently, the Rural Development Administration of the Republic of Korea produced a new paternal line to improve economic traits in pigs. However, there is an absence of information on pig traits with regard to season and sex, and a comparison between the new paternal line and past paternal lines. Therefore, the authors conducted this study to investigate the influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs. A total of 2888 piglets ((Landrace × Yorkshire) × Darby Duroc (DD) or Chookjin Duroc (CD)) with an average age of three weeks were tested for 22 weeks during the four season of the year (spring 608 piglets, summer 404 piglets, autumn 576 piglets and winter 1300 piglets). The bodyweights (BW) of individual pig were recorded, and feed consumption was recorded at weeks 2, 12 and 22, to determine growth performance. At reaching market weight, backfat thickness was determined at the last rib area. Meat was graded according to the criteria of the slaughterhouse. There were no significant differences in growth performance and carcass traits between sexes. The CD line crossbred pig had a significant higher BW at 16 weeks, and higher carcass trait values at 22 weeks than the DD line. During weeks 8 to 16 the CD line crossbred pigs showed a tendency of an increased average daily gain (ADG) and gain : feed (G : F) ratio compared with the DD line. Furthermore, pigs born in spring had significant lower ADG, average daily feed intake (ADFI) and carcass trait values than born in the other seasons. In conclusion, the new paternal line (Chookjin Duroc) improved growth performance and carcass traits compare with the DD line.Keywords: sex, growth, terminal sire, meat quality, backfat thicknes
Brain Structural Networks Associated with Intelligence and Visuomotor Ability
Increasing evidence indicates that multiple structures in the brain are associated with intelligence
and cognitive function at the network level. The association between the grey matter (GM) structural
network and intelligence and cognition is not well understood. We applied a multivariate approach
to identify the pattern of GM and link the structural network to intelligence and cognitive functions.
Structural magnetic resonance imaging was acquired from 92 healthy individuals. Source-based
morphometry analysis was applied to the imaging data to extract GM structural covariance. We
assessed the intelligence, verbal fluency, processing speed, and executive functioning of the
participants and further investigated the correlations of the GM structural networks with intelligence
and cognitive functions. Six GM structural networks were identified. The cerebello-parietal component
and the frontal component were significantly associated with intelligence. The parietal and frontal
regions were each distinctively associated with intelligence by maintaining structural networks with
the cerebellum and the temporal region, respectively. The cerebellar component was associated
with visuomotor ability. Our results support the parieto-frontal integration theory of intelligence by
demonstrating how each core region for intelligence works in concert with other regions. In addition,
we revealed how the cerebellum is associated with intelligence and cognitive functions
Broilers fed a low protein diet supplemented with synthetic amino acids maintained growth performance and retained intestinal integrity while reducing nitrogen excretion when raised under poor sanitary conditions
The present study investigated the effects of supplementing a low protein (LP) diet supplemented with key essential amino acids (AA) to broilers on growth performance, intestinal tract function, blood metabolites, and nitrogen excretion when the animals were maintained under various sanitary conditions for 35 D after hatching. Three hundred eighty-four one-day-old male broilers (Ross 308) were randomly allotted to groups that received one of 6 dietary treatments in a 2 × 3 factorial arrangement (i.e., 2 environmental conditions and 3 dietary treatments) to give 8 replicates per treatment. Broilers were challenged with 2 environmental conditions (sanitary vs. poor sanitary). The dietary treatments were (1) high protein (HP) diet, (2) LP diet, and (3) LP diet with synthetic key essential AA (LPA): the LP diet was supplemented with synthetic AA up to the required levels for broilers. On day 14, birds consumed the LP diet impaired growth performance compared with those fed the HP diet, while the average daily weight gain-to-feed conversion ratio of birds fed the LPA diet improved to the level of birds fed the HP diet under poor sanitary conditions (P < 0.05). Broilers raised under poor sanitary conditions and fed the LP diet displayed higher (P < 0.05) zonula occludens (ZO-1) expression on day 14 than broilers fed either the HP or LPA diet. Under sanitary conditions, birds fed HP and LPA diets showed higher villus height and crypt depth compared with those of broilers fed the LP diet on day 35. Moreover, broilers raised in the poor sanitary environment had higher (P < 0.05) serum endotoxins than those raised in the sanitary environment. Broilers fed the LPA diet showed reduced (P < 0.05) nitrogen excretion on days 14 and 35 compared with those fed the LP and HP diets independent of the environment. In conclusion, the LPA diet did not impair growth performance under poor sanitary conditions for 14 D after hatch while resulting in lower nitrogen excretion in any environment conditions throughout the experiment
Constitutive activation of T cells by γ2-herpesviral GPCR through the interaction with cellular CXCR4
Members of the herpesviral family use multiple strategies to hijack infected host cells and exploit cellular signaling for their pathogenesis and latent infection. Among the most intriguing weapons in the arsenal of pathogenic herpesviruses are the constitutively active virally-encoded G protein-coupled receptors (vGPCRs). Even though vGPCRs contribute to viral pathogenesis such as immune evasion and proliferative disorders, the molecular details of how vGPCRs continuously activate cellular signaling are largely unknown. Here, we report that the vGPCR of Herpesvirus saimiri (HVS), an oncogenic gamma 2-herpesvirus, constitutively activates T cells via a heteromeric interaction with cellular CXCR4. Constitutive T cell activation also occurs with expression of the vGPCR of Kaposi's sarcoma-associated herpesvirus (KSHV), but not the vGPCR of Epstein-Barr virus. Expression of HVS vGPCR down-regulated the surface expression of CXCR4 but did not induce the degradation of the chemokine receptor, suggesting that vGPCR/CXCR4 signaling continues in cytosolic compartments. The physical association of vGPCR with CXCR4 was demonstrated by proximity ligation assay as well as immunoprecipitation. Interestingly, the constitutive activation of T cells by HVS vGPCR is independent of proximal T cell receptor (TCR) signaling molecules, such as TcR beta, Lck, and ZAP70, whereas CXCR4 silencing by shRNA abolished T cell activation by vGPCRs of HVS and KSHV. Furthermore, previously identified inactive vGPCR mutants failed to interact with CXCR4. These findings on the positive cooperativity of vGPCR with cellular CXCR4 in T cell activation extend our current understanding of the molecular mechanisms of vGPCR function and highlight the importance of heteromerization for GPCR activity. (C) 2016 Elsevier B.V. All rights reserved.1111Ysciescopu
Gravity and Geometric Phases
The behavior of a quantum test particle satisfying the Klein-Gordon equation
in a certain class of 4 dimensional stationary space-times is examined. In a
space-time of a spinning cosmic string, the wave function of a particle in a
box is shown to acquire a geometric phase when the box is transported around a
closed path surrounding the string. When interpreted as an Aharonov-Anandan
geometric phase, the effect is shown to be related to the Aharonov-Bohm effect.Comment: 11 pages, latex fil
Particle Motion Around Tachyon Monopole
Recently, Li and Liu have studied global monoole of tachyon in a four
dimensional static space-time. We analyze the motion of massless and massive
particles around tachyon monopole. Interestingly, for the bending of light rays
due to tachyon monopole instead of getting angle of deficit we find angle of
surplus. Also we find that the tachyon monopole exerts an attractive
gravitational force towards matter.Comment: 14 pages, 7 figure
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