bluuebunny/crossref_metadata_2025_split huggingface dataset:
A time‐based adaptive retry strategy for video streaming in 802.11 WLANs
Authors: Lu Mei‐Hsuan , Steenkiste Peter , Chen Tsuhan 
Published: January 2007

AbstractVideo streaming over time‐varying, error‐prone wireless LANs (WLANs) poses many challenges. One problem is that WLANs are designed without awareness of the characteristics of application data, which causes performance degradation in a noisy or congested environment. In this paper, we propose a time‐based adaptive retry (TAR) mechanism for MPEG‐like video streaming over 802.11 wireless networks. TAR dynamically determines whether to send or discard a packet based on itsretransmission deadlineinstead of adopting a static retry limit uniformly over all the packets. Our approach can adapt the retry limit for each individual packet, thus providing indirect unequal error protection over different types of video frames. Analytical and simulation results show that TAR significantly improves video quality and saves channel bandwidth. We also describe a preliminary software‐based implementation of TAR and use it to demonstrate the practicality of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd.
Self-organization of stack-up block copolymers into polymeric supramolecules
Authors: Yuan Yong J. , Choi Ka-Wai , Wong Herbert 
Published: January 2007

Abstract
Polyethylene oxide –b– polypropylene oxide -b- polyethylene oxide (EO106PO70EO106) block copolymer self-organizes into polymeric supramolecules, characterized by NMR as phase transition from the isotropic stack-up block structure to the ordered cubic polymeric supramolecular structure. Its dependence on both temperature and copolymer concentration is clearly shown by the changes in line shape and chemical shift of the PO70blockβ,γ resonances.
Uniqueness of the critical mass blow up solution for the four dimensional gravitational Vlasov–Poisson system
Authors: Lemou Mohammed , Méhats Florian , Raphaël Pierre 
Published: January 2007

We study the gravitational Vlasov–Poisson system

\partial _{t}f + v \cdot \mathrm{∇}_{x}f−E \cdot \mathrm{∇}_{v}f = 0

,

E(x) = \mathrm{∇}\phi (x)

,

\mathrm{\Delta }\phi (x) = \int f(x,v)\:\mathrm{d}v

, in dimension

N = 4

where the problem is

L^{1}

critical. We proved in [M. Lemou, F. Méhats, P. Raphael, On the orbital stability of the ground states and the singularity formation for the gravitational Vlasov Poisson system, preprint] a sharp criterion for the global existence of weak solutions based on the variational characterization of the polytropic steady states solutions. From the existence of a pseudo-conformal symmetry, this criterion is sharp and there exist critical mass blow up solutions. We prove in this paper the uniqueness of the critical mass blow up solution. This gives in particular a first dynamical classification of the polytropic stationary solutions. The proof is an adaptation of a similar result by Frank Merle [F. Merle, Determination of blow-up solutions with minimal mass for nonlinear Schrödinger equations with critical power, Duke Math. J. 69 (2) (1993) 427–454] for the

L^{2}

critical nonlinear Schrödinger equation.

Résumé

Nous considérons le système de Vlasov–Poisson

\partial _{t}f + v \cdot \mathrm{∇}_{x}f−E \cdot \mathrm{∇}_{v}f = 0

,

E(x) = \mathrm{∇}\phi (x)

,

\mathrm{\Delta }\phi (x) = \int f(x,v)\:\mathrm{d}v

, en dimension

N = 4

où le problème est

L^{1}

critique. En se basant sur une caractérisation variationnelle des solutions stationnaires polytropiques, nous avons établi dans [M. Lemou, F. Méhats, P. Raphael, On the orbital stability of the ground states and the singularity formation for the gravitational Vlasov Poisson system, preprint] un critère optimal garantissant l'existence globale de solutions faibles pour ce système. L'optimalité de ce critère est une conséquence directe de l'existence d'une symétrie pseudo-conforme qui permet d'exhiber des solutions explosives de masse critique. Nous démontrons ici l'unicité de la solution explosive de masse critique. La preuve est une adaptation d'un résultat similaire de Frank Merle [F. Merle, Determination of blow-up solutions with minimal mass for nonlinear Schrödinger equations with critical power, Duke Math. J. 69 (2) (1993) 427–454] pour l'équation de Schrödinger non linéaire

L^{2}

critique.
Optimization of the sampling strategy for establishing a gene bank: storing PrP alleles following a scrapie eradication plan as a case study
Authors: Fernández J. , Roughsedge T. , Woolliams J. A. , Villanueva B. 
Published: January 2007

AbstractGene banks are usually used for storing general genetic variability of endangered living populations but can be also used for storing alleles of a particular locus that are being eradicated through artificial selection programmes. In such scenarios gene banks would allow future re-introduction of one or more of the alleles being eradicated (and the associated diversity) into living populations. Frequencies within the bank for the locus of interest should have pre-determined target values. In this study, an algorithm is derived to obtain the optimal contributions of all candidate donors to achieve the target frequencies of the removed alleles in the bank while maintaining at the same time genetic variability in other loci unlinked to those targeted in the eradication programme. The efficiency of the algorithm is tested using the case of gene banks storing prion protein alleles currently disfavoured in scrapie eradication programmes (i.e., the AHQ, ARH, ARQ and VRQ alleles). Results showed that the algorithm was able to find the combinations of candidate contributions fulfilling different objectives regarding target frequencies and restrictions on coancestry. The most important factors influencing the optimal contributions were the allelic frequencies and the levels of diversity (coancestry) of the living population. Heterozygotes were favoured over homozygous individuals as, for a given number of animals contributing to the bank, the use of heterozygotes leads to lower levels of coancestry. Notwithstanding, almost all donors were sampled when restrictions on the global genetic diversity to be stored were severe.
Prediction of the percentage lean of pig carcasses with a small or a large number of instrumental carcass measurements – an illustration with HGP and Vision
Authors: Engel B. , Lambooij E. , Buist W. G. , Reimert H. , Mateman G. 
Published: January 2007

AbstractIn this paper we report on the results of a recent dissection experiment in The Netherlands where prediction formulae for the percentage lean meat in pig carcasses with the Hennessy Grading Probe (HGP) and a vision system (from now on referred to as Vision) were determined. Predictions with the HGP were based on one fat and one muscle depth measurement only, while predictions with Vision were based on as many as 115 direct and derived measurements. The data from this dissection experiment were used to illustrate the statistical calculations involved in relation to the number of carcass measurements. Prediction with instruments that gather a large number of measurements per carcass is not covered by the present European Community (EC) regulations. Therefore the calculations were conducted according to new regulations for statistical methodology in pig carcass grading that are expected to be adopted by the EC in the near future. The calculations included consideration of 3 subpopulations (females, entire males and castrated males). The Vision data were also used to show that ordinary regression after selection of a subset of carcass measurements severely under estimates the accuracy of prediction: instruments and associated prediction formulae are seemingly much more accurate than they truly are. When standard regression methods are used for instruments that gather a large number of measurements, there is a considerable risk that measurement instruments will be selected for the wrong reasons. Accuracy of approved instruments may not even comply with the EC-regulations, with poor consequences for harmonization within the EC.
Influence of energy intake on protein and lipid deposition in Creole and Large White growing pigs in a humid tropical climate
Authors: Renaudeau D. , Bocage B. , Noblet J. 
Published: January 2007

AbstractTwenty-four castrated males were used to study the effect of breed (Large Whitev. Creole (LWv. CR)) and feeding level (0·70, 0·80, 0·90, and 1·00 ad libitum) on growth performance and protein deposition (PD) and lipid deposition (LD) between 30 and 60 kg in growing pigs under tropical climatic conditions; the CR pigs are raised in the Caribbean area and can be qualified as fat and slow growing pigs. Daily protein and amino acids supplies were calculated to be non-limiting for protein gain. Total PD and LD were measured according to the comparative slaughter technique. Digestibility coefficients of energy and nutrients were estimated over a 10-day period at 45 kg live weight. Neither the breed nor the feeding level influenced the apparent digestibility coefficients of dietary nutrients; only energy digestibility was increased at reduced feeding levels (P<0·05). Average daily gain increased linearly with the increase of metabolizable energy (ME) intake and the slope of the relationship was lower in CR than in LW pigs (30·4v. 36·6 g per additional MJ ME). The food conversion ratio was not affected by feeding level but it was significantly higher in CR than in LW pigs (2·88v. 2·36 kg /kg;P<0·001). Daily PD increased with ME intake according to a linear relationship in both breeds and the slope was significantly affected by breed (3·1v. 4·2 g/MJ ME in CR and LW pigs, respectively;P<0·001). In contrast, the increase of LD and total energy retained with ME were higher in CR than in LW pigs (8·4v. 6·4 g/MJ and 0·40v. 0·36 MJ/ MJ ME, respectively;P<0·001).
Effects of plane of nutrition during the first month of pregnancy on conception rate, foetal development and lamb output of mature and adolescent ewes
Authors: Annett R. W. , Carson A. F. 
Published: January 2007

AbstractEmbryo transfer studies have demonstrated that high plane feeding in early pregnancy is detrimental to the successful establishment of pregnancy in adolescent but not mature ewes. To further examine this relationship with ewes that conceive naturally and to investigate its effects on foetal development, 102 Greyface and Texel×Greyface ewes (body condition score (BCS) 3·8) and 114 Texel×Greyface adolescent ewes (BCS 3·3) were allocated to one of three treatments following a synchronized mating. From day 1 to 31 of pregnancy, animals were offered grass nuts (10·2 MJ metabolizable energy (ME) per kg dry matter (DM); 163 g crude protein per kg DM) at one of three levels to supply approximately 2·0 (H); 1·0 (M) and 0·6 (L) of their predicted ME requirements for maintenance. Increasing the post-mating plane of nutrition resulted in significant increases in ewe live weight (P<0·001) and BCS (P<0·001) during the treatment period. When diets were standardized for all animals during mid pregnancy (days 31 to 105), L ewes gained more live weight (P<0·05) and BCS (P<0·001) than H ewes. Early pregnancy nutrition had no effect on the conception rate of mature ewes; however adolescent ewes on the H and M treatments had lower conception rates (P<0·05) than those offered the L diet (0·59, 0·61 and 0·82 respectively). As a result, L adolescent ewes tended to have a higher mean total lamb birth weight per ewe mated (P=0·09) although lamb output at weaning was not influenced by plane of nutrition. Lambs born from adolescent mothers had lower lamb birth weights (P<0·001) and a shorter mean head length, crown-rump length and thoracic girth (P<0·001). Foetuses from H ewes had longer hind legs than those from L ewes on day 83 of gestation (P<0·05) and at term (P<0·05). The results of this study suggest that allowing adolescent but not mature ewes to lose live weight and body condition can increase the proportion of productive ewes following a natural service.
The influence of apple- and red-wine pomace rich diet on mRNA expression of inflammatory and apoptotic markers in different piglet organs
Authors: Sehm J. , Lindermayer H. , Meyer H. H. D. , Pfaffl M. W. 
Published: January 2007

Flavan-3-ols are a class of flavonoids that are widely distributed in fruits and beverages including red wine and apples. Consumption of flavanoid-rich food has been shown to exhibit anti-microbial, anti-oxidative, anti-inflammatory, and immune-modulating effects. To test the nutritional effects of flavanols on mRNA gene-expression of inflammatory and apoptotic marker genes, piglets were given two flavanoids-rich feeding regimens: a low flavanoid standard diet (SD) was compared with diets enriched with 3·5% apple pomace (APD) or 3·5% red-wine pomace (RWPD). The influence on mRNA expression levels was investigated in different immunological active tissues and in the gastro-intestinal tract (GIT). The investigation took place from 1 week prior weaning to 19 days post weaning in 78 piglets. The expression of expressed marker genes was determinate by one-step quantitative real-time (qRT-PCR): TNFα, NFκB as pro-inflammatory; IL10, as anti-inflammatory; caspase 3 as apoptosis; cyclin D1 as cell cycle marker; and nucleosome component histon H3 as reference gene.The feeding regimens result in tissue individual regulation of mRNA gene expression in all investigated organs. It was discovered that there were significant differences between the applied diets and significant changes during feeding time curse. Both pomace treatments caused a significant up-regulation of all investigated genes in liver. The effect on mesenterial lymph nodes and spleen was not prominent. In the GIT, the treatment groups showed a inhibitory effects on gene expression mainly in stomach and jejunum (NFκB, cyclin D1 and caspase 3). In colon the trend of caspase 3 was positive with the greatest change in the RWPD group.In jejunum and stomach the cell cycle turn over was reduced, whereas in liver the cell turn over was highly accelerate. The influence on inflammatory marker gene expression is mainly relevant in stomach. It is presume that both flavanoid rich feeding regimens have the potential to modulate the mRNA expressions of inflammatory, proliferation and apoptotic marker genes in the GIT and piglet organs.
Selective melanocortin MC4receptor agonists reverse haemorrhagic shock and prevent multiple organ damage
Authors: Giuliani D , Mioni C , Bazzani C , Zaffe D , Botticelli A R , Capolongo S , Sabba A , Galantucci M , Iannone A , Grieco P , Novellino E , Colombo G , Tomasi A , Catania A , Guarini S 
Published: January 2007

Background and purpose:In circulatory shock, melanocortins have life‐saving effects likely to be mediated by MC4receptors. To gain direct insight into the role of melanocortin MC4receptors in haemorrhagic shock, we investigated the effects of two novel selective MC4receptor agonists.Experimental approach:Severe haemorrhagic shock was produced in rats under general anaesthesia. Rats were then treated with either the non‐selective agonist [Nle4, D‐Phe7]α‐melanocyte‐stimulating hormone (NDP‐α‐MSH) or with the selective MC4agonists RO27‐3225 and PG‐931. Cardiovascular and respiratory functions were continuously monitored for 2 h; survival rate was recorded up to 24 h. Free radicals in blood were measured using electron spin resonance spectrometry; tissue damage was evaluated histologically 25 min or 24 h after treatment.Key results:All shocked rats treated with saline died within 30‐35 min. Treatment with NDP‐α‐MSH, RO27‐3225 and PG‐931 produced a dose‐dependent (13‐108 nmol kg‐1i.v.) restoration of cardiovascular and respiratory functions, and improved survival. The three melanocortin agonists also markedly reduced circulating free radicals relative to saline‐treated shocked rats. All these effects were prevented by i.p. pretreatment with the selective MC4receptor antagonist HS024. Moreover, treatment with RO27‐3225 prevented morphological and immunocytochemical changes in heart, lung, liver, and kidney, at both early (25 min) and late (24 h) intervals.Conclusions and Implications:Stimulation of MC4receptors reversed haemorrhagic shock, reduced multiple organ damage and improved survival. Our findings suggest that selective MC4receptor agonists could have a protective role against multiple organ failure following circulatory shock.British Journal of Pharmacology(2007)150, 595–603. doi:10.1038/sj.bjp.0707115
The psychoactive plant cannabinoid, Δ9‐tetrahydrocannabinol, is antagonized by Δ8‐ and Δ9‐tetrahydrocannabivarin in micein vivo
Authors: Pertwee R G , Thomas A , Stevenson L A , Ross R A , Varvel S A , Lichtman A H , Martin B R , Razdan R K 
Published: January 2007

Background and purpose:To follow upin vitroevidence that Δ9‐tetrahydrocannabivarin extracted from cannabis (eΔ9‐THCV) is a CB1receptor antagonist by establishing whether synthetic Δ9‐tetrahydrocannabivarin (O‐4394) and Δ8‐tetrahydrocannabivarin (O‐4395) behave as CB1antagonistsin vivo.Experimental approach:O‐4394 and O‐4395 were compared with eΔ9‐THCV as displacers of [3H]‐CP55940 from specific CB1binding sites on mouse brain membranes and as antagonists of CP55940 in [35S]GTPγS binding assays performed with mouse brain membranes and ofR‐(+)‐WIN55212 in mouse isolated vasa deferentia. Their ability to antagonizein vivoeffects of 3 or 10 mg kg−1(i.v.) Δ9‐tetrahydrocannabinol in mice was then investigated.Key results:O‐4394 and O‐4395 exhibited similar potencies to eΔ9‐THCV as displacers of [3H]‐CP55940 (Ki=46.6 and 64.4 nM, respectively) and as antagonists of CP55940 in the [35S]GTPγS binding assay (apparentKB=82.1 and 125.9 nM, respectively) andR‐(+)‐WIN55212 in the vas deferens (apparentKB=4.8 and 3.9 nM respectively). At i.v. doses of 0.1, 0.3, 1.0 and/or 3 mg kg−1O‐4394 and O‐4395 attenuated Δ9‐tetrahydrocannabinol‐induced anti‐nociception (tail‐flick test) and hypothermia (rectal temperature). O‐4395 but not O‐4394 also antagonized Δ9‐tetrahydrocannabinol‐induced ring immobility. By themselves, O‐4395 and O‐4394 induced ring immobility at 3 or 10 mg kg−1(i.v.) and antinociception at doses above 10 mg kg−1(i.v.). O‐4395 also induced hypothermia at 3 mg kg−1(i.v.) and above.Conclusions and implications:O‐4394 and O‐4395 exhibit similarin vitropotencies to eΔ9‐THCV as CB1receptor ligands and as antagonists of cannabinoid receptor agonists and can antagonize Δ9‐tetrahydrocannabinolin vivo.British Journal of Pharmacology(2007)150, 586–594. doi:10.1038/sj.bjp.0707124
Cannabidiol displays unexpectedly high potency as an antagonist of CB1and CB2receptor agonistsin vitro
Authors: Thomas A , Baillie G L , Phillips A M , Razdan R K , Ross R A , Pertwee R G 
Published: January 2007

Background and purpose:A nonpsychoactive constituent of the cannabis plant, cannabidiol has been demonstrated to have low affinity for both cannabinoid CB1and CB2receptors. We have shown previously that cannabidiol can enhance electrically evoked contractions of the mouse vas deferens, suggestive of inverse agonism. We have also shown that cannabidiol can antagonize cannabinoid receptor agonists in this tissue with a greater potency than we would expect from its poor affinity for cannabinoid receptors. This study aimed to investigate whether these properties of cannabidiol extend to CB1receptors expressed in mouse brain and to human CB2receptors that have been transfected into CHO cells.Experimental approach:The [35S]GTPγS binding assay was used to determine both the efficacy of cannabidiol and the ability of cannabidiol to antagonize cannabinoid receptor agonists (CP55940 andR‐(+)‐WIN55212) at the mouse CB1and the human CB2receptor.Key results:This paper reports firstly that cannabidiol displays inverse agonism at the human CB2receptor. Secondly, we demonstrate that cannabidiol is a high potency antagonist of cannabinoid receptor agonists in mouse brain and in membranes from CHO cells transfected with human CB2receptors.Conclusions and implications:This study has provided the first evidence that cannabidiol can display CB2receptor inverse agonism, an action that appears to be responsible for its antagonism of CP55940 at the human CB2receptor. The ability of cannabidiol to behave as a CB2receptor inverse agonist may contribute to its documented anti‐inflammatory properties.British Journal of Pharmacology(2007)150, 613–623. doi:10.1038/sj.bjp.0707133
Endothelium‐dependent metabolism by endocannabinoid hydrolases and cyclooxygenases limits vasorelaxation to anandamide and 2‐arachidonoylglycerol
Authors: Ho W‐Sv , Randall M D 
Published: January 2007

Background and purpose:The endocannabinoids, N‐arachidonoylethanolamide (anandamide) and 2‐arachidonoylglycerol (2‐AG) are rapidly degraded by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL). Whilst these lipid mediators are known to modulate vascular tone, the extent to which they are inactivated via local metabolism in the vasculature remains unclear.Experimental approach:In rat isolated small mesenteric arteries, the regulatory role of FAAH, MGL and cyclooxygenase (COX) in relaxant responses to anandamide and 2‐AG was evaluated by using inhibitors of these enzymes. Relaxations to non‐hydrolysable analogues of endocannabinoids and arachidonic acid were also examined.Key results:Relaxation to anandamide but not 2‐AG was potentiated by the selective FAAH inhibitor, URB597 (1 μM). In contrast, MAFP (10 μM; an inhibitor of FAAH and MGL) enhanced responses to both anandamide and 2‐AG. Inhibition of COX‐1 by indomethacin (10 μM) potentiated relaxations to 2‐AG, whereas inhibition of COX‐2 by nimesulide (10 μM) potentiated anandamide‐induced relaxation. With the exception of MAFP, effects of FAAH and COX inhibitors were dependent on the endothelium. Relaxation to methanandamide and noladin ether, the non‐hydrolysable analogues of anandamide and 2‐AG respectively, were insensitive to the enzyme inhibitors.Conclusion and implications:This study shows that local activity of FAAH, MGL and COX, which is present largely in the endothelium, limits the vasodilator action of endocannabinoids in rat small mesenteric arteries. Despite the differential roles played by these enzymes on relaxation to anandamide versus 2‐AG, our results suggest that inhibitors of these enzymes enhance the vascular impact of endocannabinoids.British Journal of Pharmacology (2007) 150, 641–651. doi:10.1038/sj.bjp.0707141
Spatiotemporal Filtering and the Interpolation Effect in Apparent Motion
Authors: Morgan Michael J 
Published: January 2007

A target moving in discrete spatial steps with an appropriate interstep interval (ISI) can appear visually as if it is in continuous motion. The momentary spatial position of such a target is interpolated by the observer between its real physical positions. The extent of this interpolation was measured by a vernier alignment technique, and was found to decrease as the ISI was lengthened. A discretely moving target may be described as a continuously moving target on which is superimposed a periodic modulation of spatial position. It is shown that the traditional ‘staircase’ stimulus for apparent motion can be generalized to include other kinds of periodic modulation. With the use of various analog-filtered and digitally filtered versions of staircase stimuli with different ISIs, it was shown that the phenomenal interpolation of a periodically modulated moving target was affected only when the frequencies of modulation were less than about 25 Hz. The spatial amplitude of the modulation also has some effect.