bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel QoS‐aware MAC protocol for voice services over IEEE 802.11‐based WLANs
Authors: Qaimkhani Irshad A. , Hossain Ekram 
Published: June 2008

AbstractWith the pervasive growth in the popularity of IEEE 802.11‐based wireless local area networks (WLANs) worldwide, the demand to support delay‐sensitive services such as voice has increased very rapidly. This paper provides a comprehensive survey on the medium access control (MAC) architectures and quality of service (QoS) provisioning issues for WLANs. The major challenges in providing QoS to voice services through WLAN MAC protocols are outlined and the solution approaches proposed in the literature are reviewed. To this end, a novel QoS‐aware wireless MAC protocol, called hybrid contention‐free access (H‐CFA) protocol and a call admission control technique, called traffic stream admission control (TS‐AC) algorithm, are presented. The H‐CFA protocol is based on a novel idea that combines two contention‐free wireless medium access approaches, that is, round‐robin polling and time‐division multiple access (TDMA)‐like time slot assignment, and it increases the capacity of WLANs through efficient silence suppression. The TS‐AC algorithm ensures efficient admission control for consistent delay‐bound guarantees and further maximizes the capacity through exploiting the voice characteristic that it can tolerate some level of inconsecutive packet loss. The benefits of the proposed schemes are demonstrated in the simulations results. Copyright © 2008 John Wiley & Sons, Ltd.
On the characteristics and compatibility equations for the UCM model fluid
Authors: Gerritsma M.I. , Phillips T.N. 
Published: June 2008

AbstractThe quasilinear system of partial differential equations governing the flow of a UCM fluid is known to be of mixed elliptic‐hyperbolic type. The compatibility equations associated with the hyperbolic part of the system are derived in this paper. There are two characteristic variables that are transported along the characteristics. These are both associated with the conditional well‐posedness of the system. The compatibility equations in this case are derived from the constitutive equation alone. There are two additional characteristics that are always present for unsteady inertial flow and which may be present for steady inertial flow. The compatibility equations associated with these characteristics involve a coupling between the momentum and constitutive equations. At an inflow boundary, it is shown that all stress components can be prescribed, despite the fact that there are only two characteristic variables that enter the domain along the streamlines. The remaining stress component is provided by fixing the incoming elastic shear waves.
Where do fractional derivatives in stress strain relations come from? A structural approach
Authors: Pfitzenreiter T. 
Published: June 2008

AbstractExperiments have shown that the material behaviour of plastics, especially the viscous damping, can be described in an excellent way by the introduction of fractional derivatives in stress strain relations. From the coincidence between model and experiment the question of a deeper physical explanation arises. In this paper we will construct a structural model of polymers which explains why fractional derivatives in damping terms of stress strain relations arise.
Quasistatic inflation processes within rigid tubes
Authors: Steigenberger J. , Abeszer H. 
Published: June 2008

AbstractIn this paper the authors consider mechanical devices of rotational symmetry that can be seen as segments of an artificial worm or as a balloon for angioplasty. Continuing former work [7] the segment is now placed within a cylindrical or constricted rigid tube that will be touched or pressed during inflation of the segment. Both the segment's shape and the forces of contact are investigated. The main mathematical tool is the Principle of Minimal Potential Energy – handled as an optimal control problem with state constraint. The necessary optimality conditions are carefully analyzed and simulation results for characteristic examples are presented. The treatment of the problem is primarily mathematical but aiming at application.
Essentially nonlinear vibration absorber in a parametrically excited system
Authors: Shiroky I.B. , Gendelman O.V. 
Published: June 2008

AbstractDynamics and performance of a strongly nonlinear attachment in a parametrically excited system are examined. Dynamic behavior of the system is analyzed and the conditions for the various regimes of oscillation are revealed. Addition of the essentially nonlinear attachment to linear parametrically excited system brings about a family of responses with bounded amplitude and thus prevents the exponential divergence typical for the parametric resonance. Regimes and conditions, optimal for the vibration absorption, are described.
Image‐Guided Liver Mapping Using Fluorescence Navigation System with Indocyanine Green for Anatomical Hepatic Resection
Authors: Aoki Takeshi , Yasuda Daisuke , Shimizu Yoshinori , Odaira Masanori , Niiya Takashi , Kusano Tomokazu , Mitamura Keitaro , Hayashi Ken , Murai Noriyuki , Koizumi Tomotake , Kato Hirohisa , Enami Yuta , Miwa Mitsuharu , Kusano Mitsuo 
Published: June 2008

AbstractBackgroundIn malignant hepatic neoplasm, anatomic resection could improve survival and limit complications from hepatectomy. Our purpose was to develop an intraoperative method for identifying segment and subsegment of the liver with high‐sensitivity near‐infrared fluorescence imaging.MethodsThe subjects were 35 patients with hepatic malignant liver disease who received hepatectomy in 2006. The segments of liver method of identification that used infrared observation camera system termed Photo Dynamic Eye‐2 (PDE‐2) with indocianine green (ICG) for the patient with malignant liver tumor (hepatocellular carcinoma: 13 cases; metastatic liver cancer: 18 cases; intrahepatic cholangio carcinoma: 4 cases) were performed before liver resection.ResultsAlthough greenish stain of the liver surface after the injection of ICG via portal vein is not visible clearly without infrared observation camera system PDE‐2, 1 minute after injection of ICG with fluorescent using infrared observation camera system PDE‐2, demarcation of liver segment and subsegment was clearly detected. Ten minutes after injection of ICG with fluorescent using infrared observation camera system PDE‐2, fluorescence of liver subsegment remained. Stained subsegment and segment of liver were identifiable in 33 (94.3%) of the 35 patients. There were no complications or side‐effects related to the injection of patent blue dye.ConclusionWe demonstrated here that near‐infrared fluorescence imaging system is a novel and reliable intraoperative technique to identify hepatic segment and subsegment for anatomical hepatic resection.
Thrombosis Confined to the Portal Vein Is Not a Contraindication for Living Donor Liver Transplantation
Authors: Cho Jai Young , Suh Kyung‐Suk , Shin Woo Young , Lee Hae Won , Yi Nam‐Joon , Lee Kuhn Uk 
Published: June 2008

AbstractBackgroundThere is a lack of agreement regarding preexisting portal vein thrombosis (PVT) in patients undergoing living donor liver transplantation (LDLT). We report the results of a single‐center study to determine the impact of PVT on outcomes of adult LDLT recipients.MethodsOf 133 cases of adult LDLT performed between January 2000 and December 2004, a thrombectomy was performed on 22 patients (16.5%) with PVT during the transplant procedure. One hundred eleven patients without PVT (group 1) were compared with those with a thrombosis confined to the portal vein (group 2; n = 15) and patients with the thrombosis beyond the portal vein (group 3; n = 7).ResultsThe sensitivities of Doppler ultrasound and CT in detecting PVT were 50 and 63.6%. A prior history of variceal bleeding (OR = 10.6, p = 0.002) and surgical shunt surgery (OR = 28.1, p = 0.044) were found to be an independent risk factors for PVT. The rate of postoperative PVT was significantly higher in patients with PVT than in those without (18.2 vs. 2.7%; p = 0.014). In particular, the rethrombosis rate in group 3 was 28.6%. The actuarial 3‐year patient survival rate in PVT patients (73.6%) was similar to that of the non‐PVT patients (85.3%; p = 0.351). However, the actuarial 3‐year patient survival rate in group 3 was 38.1%, which was significantly lower than that in groups 1 and 2 (p = 0.006).ConclusionA thrombosis confined to the portal vein per se should not be considered a contraindication for LDLT.
Relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on vertebrate species richness in Spain
Authors: Moreno‐Rueda Gregorio , Pizarro Manuel 
Published: June 2008

AbstractMany factors affect the distribution of species richness. This study examines the relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on the species‐richness distribution of terrestrial vertebrates (amphibians, reptiles, birds and mammals) in mainland Spain. The results indicate that spatial structure and environment exert similar influences on species richness. For all four taxa, species richness increases southward and northward, being lower in the center of the country, when controlled for other variables. This may be the result of a peninsular effect, as found in other studies, and reflect the importance of historical events on species richness in the Iberian Peninsula. Climate is more important than habitat heterogeneity in determining species richness. Temperature is positively correlated with amphibian, reptile, and bird species richness, while mammalian species richness is highest at intermediate temperatures. This effect is stronger in ectotherms than among endotherms, perhaps reflecting physiological differences. Precipitation positively correlates with bird and mammalian species richness, but has no effect on ectotherm species richness. Amphibian species richness increases with altitudinal range, and bird species richness with habitat diversity. Human population density is positively correlated with bird and mammalian species richness, but does not affect ectotherm species richness, while amphibian and bird species richness is highest at moderate levels of human land alteration (farmland). However, unexplained variance remains, and we discuss that the effects of environmental variables on species richness may vary geographically, causing different effects to be obscured on a national scale, diminishing the explanatory power of environmental variables.
Photosynthetic CO2 affinity of the aquatic carnivorous plant Utricularia australis (Lentibulariaceae) and its investment in carnivory
Authors: Adamec Lubomír 
Published: June 2008

AbstractAquatic carnivorous plants usually grow in shallow dystrophic waters poor in inorganic N and P. Utricularia australis was chosen as a model plant for its prolific distribution and great ecological plasticity. The photosynthetic CO2 compensation point and factors associated with investment in carnivory and capture of prey were measured in 17 U. australis micropopulations in Třeboň basin, Czech Republic, together with water chemistry factors at these sites differing greatly in their trophic level, water hardness, and prey availability. Apical shoot growth rate was estimated at some oligotrophic sites. The micropopulations differed greatly in the proportion of traps with animal prey (2.7–70%, mean 26%), trap proportion to total biomass (1.4–42%, mean 26%), mean trap biomass (0.7–63 μg trap−1, mean 19 μg), and maximum trap size (1–3 mm, mean 2.0 mm). CO2 compensation points ranged from 0.7 to 6.1 μM (mean 2.6 μM). A weak HCO3− use (compensation point 0.51 mM) was found in plants growing in alkaline water. Trap biomass proportion did not correlate significantly with prey capture and CO2 compensation points with ambient [CO2]. A very rapid apical growth (2.5–4.2 new nodes day−1) occurred in sand pits. Thus, HCO3− use in U. australis can be induced by growing at very high pH. CO2 compensation points resembled those known in other aquatic non‐carnivorous plants. They did not reflect carnivory. In spite of very rapid apical shoot growth, the relative growth rate of U. australis can be zero in oligotrophic habitats without prey.
FV-Leiden- und Prothrombin-G20210A-Mutation
Authors: Pötzsch B. 
Published: June 2008

Zusammenfassung
Die Faktor-V-Leiden-Mutation und die Prothrombin-G20210A-Mutation sind mit einer Inzidenz von 2–4% und etwa 1% die häufigsten genetisch determinierten thrombophilen Risikofaktoren. Während der thrombophile Mechanismus der FV-Leiden-Mutation auf einer Hemmung der antikoagulatorischen Aktivität von aktiviertem Protein C (APC) beruht, ist der molekulare Mechanismus der Prothrombin-G20210A-Mutation nicht eindeutig geklärt. Das Vorliegen beider Mutationen erhöht das Risiko für eine venöse Thrombose, hat aber keinen wesentlichen Einfluss auf das Rezidivrisiko nach einer spontanen venösen Thrombose. Deswegen kann der Mutationsnachweis die klinische Diagnose einer Thrombophilie zwar bestätigen, beeinflusst aber – bis auf homozygote und compound-heterozygote Mutationsträger – das therapeutische Vorgehen nicht.
Contingency research in operations management practices
Authors: Sousa Rui , Voss Christopher A. 
Published: June 2008

AbstractAs operations management (OM) best practices have become mature, research on practices has begun to shift its interest from the justification of the value of those practices to the understanding of the contextual conditions under which they are effective—OM practice contingency research (OM PCR). This article sets out to examine and critique the current state of OM PCR. We review OM PCR studies through the lens of the major theoretical view on contingencies, contingency theory, along a number of relevant dimensions: contingency variables, performance variables, measurement, research design and employed form of fit. In this process, we put forward a number of tasks that need to be accomplished in order to move OM PCR forward and develop more solid conceptual foundations in which to anchor rigorous research in this area. Finally, we reflect on the theoretical arguments that underlie OM PCR (which are based on the contingency approach) and identify its limitations in fully explaining the currently observed patterns of use of OM practices and associated performance outcomes. As a result, we propose that in order to increase our understanding of these patterns, OM scholars need to study in more depth the process of selection of OM best practices by organizations. Accordingly, we put forward a framework to underpin such research integrating contingency theory and other theoretical perspectives.
Efficacy of inferior turbinate coblation for treatment of nasal obstruction
Authors: Farmer S E J , Quine S M , Eccles R 
Published: June 2008

AbstractObjective:To determine the efficacy of inferior turbinate coblation for the treatment of nasal obstruction.Methods:Twenty patients awaiting submucosal diathermy to the inferior turbinates were recruited into the study. All underwent inferior turbinate coblation. Pre-operative and post-operative nasal function was investigated using posterior rhinomanometry and subjective symptom scales.Results:There was no significant increase in nasal conductance two weeks after inferior turbinate coblation (p = 0.159). However, three months after inferior turbinate coblation, median nasal conductance had increased significantly, from 203 to 324 cm3/s (p = 0.004). The median increase in nasal conductance was 73 cm3/s or 43.5 per cent. Post-operative visual analogue patients' reported post-operative visual analogue scales scores for nasal obstruction decreased significantly, both two weeks (p = 0.006) and three months after inferior turbinate coblation (p = 0.001) when compared to Pre-operative values. There was no change in the reported severity of rhinorrhoea, nasal itching or sneezing. There was a significant relationship (ρ = −0.57, p = 0.014) between pre-operative nasal conductance and change in nasal conductance after inferior turbinate coblation.Conclusions:This study confirms the short-term efficacy of inferior turbinate coblation for the treatment of nasal obstruction. The benefit was greatest in patients with lower pre-operative nasal conductance. Objective measures of nasal obstruction may be important when selecting patients for inferior turbinate coblation.
Does methicillin-resistantStaphylococcus aureushave a significant role in the peri-operative course of patients undergoing rhinological surgery?
Authors: Philpott C M , Sharma A , McKiernan D C 
Published: June 2008

AbstractObjectives:Methicillin-resistantStaphylococcus aureusinfections are becoming an increasing problem, but the link with symptomatic sino-nasal infection has not previously been quantified. The aim of this study was to determine the incidence of methicillin-resistantStaphylococcus aureusinfection in patients undergoing sino-nasal surgery.Design:A retrospective study of case notes.Setting:A district general hospital.Patients:One hundred and fifty-one adult patients undergoing in-patient endonasal surgery over a 12-month period were considered for the study.Main outcome measures:Swab results from pre-operative screening and from any intra- and post-operative samples of infective mucopus.Results:One hundred and fifty-one patients undergoing endonasal surgery were included. All patients had pre-operative nasal swabs taken. Twenty-five patients had peri-operative microbiology samples taken. Only one middle meatal swab was found to contain methicillin-resistantStaphylococcus aureus. No patients had methicillin-resistantStaphylococcus aureusdetected on pre-operative screening.Haemophilus influenzaewas the most common organism detected.Conclusion:Methicillin-resistantStaphylococcus aureusinfection does not represent a significant source of morbidity in our practice.
Intraosseous mandibular schwannoma mimicking an odontogenic keratocyst, with a postsurgical pathological fracture
Authors: Gallego L , Junquera L , Rodríguez-Recio C , Fresno M F 
Published: June 2008

AbstractObjective:Schwannomas are slowly growing tumours derived from Schwann cells. We present a clinical case of schwannoma in the mandibular angle.Method:Case report and a review of the world literature concerning intraosseous schwannoma of the maxillofacial region.Results:Schwannomas or neurilemmomas are slow-growing, benign neoplasms derived from Schwann cells. Intraoral lesions are unusual and intraosseous schwannomas are even rarer, representing less than 1 per cent of benign primary tumours of the bones. We present a clinical case of schwannoma in the mandibular angle mimicking a keratocystic odontogenic tumour, with a complicated posterior evolution.Conclusion:Clinically, neurilemmomas are slow-growing tumours which may be present for years before becoming symptomatic. Radiographically, the image may be suggestive of a benign process such as an odontogenic keratocyst. Histological analysis of the specimens obtained is extremely important in order to establish the final diagnosis.
Common canalicular obstruction secondary to the use of Herrick lacrimal plugs, requiring endoscopic dacryocystorhinostomy
Authors: Dolan L , MacEwen C J , White P 
Published: June 2008

AbstractWe report the case of a 40-year-old woman who developed left common canalicular obstruction following insertion of a lacrimal plug. The patient underwent endoscopic dacryocystorhinostomy, revealing the presence of the lacrimal plug occluding the common canaliculus. The patient experienced symptomatic improvement of her epiphora post-operatively.
Trends in stimulated Brillouin scattering and optical phase conjugation
Authors: Ostermeyer M. , Kong H.J. , Kovalev V.I. , Harrison R.G. , Fotiadi A.A. , Mégret P. , Kalal M. , Slezak O. , Yoon J.W. , Shin J.S. , Beak D.H. , Lee S.K. , Lü Z. , Wang S. , Lin D. , Knight J.C. , Kotova N.E. , Sträßer A. , Scheikh-Obeid A. , Riesbeck T. , Meister S. , Eichler H.J. , Wang Y. , He W. , Yoshida H. , Fujita H. , Nakatsuka M. , Hatae T. , Park H. , Lim C. , Omatsu T. , Nawata K. , Shiba N. , Antipov O.L. , Kuznetsov M.S. , Zakharov N.G. 
Published: June 2008

AbstractAn overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.
Frobenius n-homomorphisms, transfers and branched coverings
Authors: BUCHSTABER V. M. , REES E. G. 
Published: June 2008

In this paper, the affiliations and names of the authors were misplaced. The correct information is:
V.M. BuchstaberSteklov Mathematical Institute, RAS, Gubkina 8, 119991 Moscowand School of Mathematics, University of Manchester, Manchester M13 9PL.and E.G. ReesSchool of Mathematics, University of Edinburgh, Edinburgh EH9 3JZand Heilbronn Institute for Mathematical Research, University of Bristol, Bristol BS8 1TW.
The Editor apologises for this error.
Cytopathogenicity and molecular subtyping ofLegionella pneumophilaenvironmental isolates from 17 hospitals
Authors: GARCIA-NUÑEZ M. , PEDRO-BOTET M. L. , RAGULL S. , SOPENA N. , MORERA J. , REY-JOLY C. , SABRIA M. 
Published: June 2008

SUMMARYThe cytopathogenicity of 22Legionella pneumophilaisolates from 17 hospitals was determined by assessing the dose of bacteria necessary to produce 50% cytopathic effect (CPED50) in U937 human-derived macrophages. All isolates were able to infect and grow in macrophage-like cells (range log10CPED50: 2·67–6·73 c.f.u./ml). Five groups were established and related to the serogroup, the number of PFGE patterns coexisting in the same hospital water distribution system, and the possible reporting of hospital-acquired Legionnaires' disease cases.L. pneumophilaserogroup 1 isolates had the highest cytopathogenicity (P=0·003). Moreover, a trend to more cytopathogenic groups (groups 1–3) in hospitals with more than one PFGE pattern ofL. pneumophilain the water distribution system (60%vs. 17%) and in hospitals reporting cases of hospital-acquired Legionnaires' disease (36·3%vs. 16·6%) was observed. We conclude that the cytopathogenicty of environmentalL. pneumophilashould be taken into account in evaluating the risk of a contaminated water reservoir in a hospital and hospital acquisition of Legionnaires' disease.
Deep dehydration ofUmbilicaria aprinathalli observed by proton NMR and sorption isotherm
Authors: Harańczyk H. , Bacior M. , Olech M.A. 
Published: June 2008

AbstractThe initial stages ofUmbilicaria aprinaNyl. hydration (starting from the hydration level Δm/m0 = 0.048 ± 0.004) were observed using hydration kinetics, sorption isotherm and proton NMR. The thalli were hydrated from gaseous phase. The total saturation hydration level obtained at the relative humidityp/p0 = 100% was Δm/m0 = 0.848 ± 0.009. The hydration courses revealed i) a fraction of very tightly bound water (Δm/m0 = 0.054 ± 0.011, short hydration time constant, thyd), ii) a fraction of tightly bound water [Δm/m0 = 0.051 ± 0.038, thyd = (4.7 ± 2.6) h], and iii) a loosely bound water pool [thyd = (31.0 ± 1.9) h] for higher values of target humidity. The sorption isotherm ofU. aprinawas fitted well using Dent model. The relative mass of water saturating primary binding sites was ΔM/m0 = 0.054, which is close to the water fractions. Proton FIDs detected (i + ii) the immobilized tightly bound water fraction, L1, and iii) the mobile, loosely bound water pool L2. The hydration dependence of the proton liquid signal suggests the presence of a significant contribution from a water soluble solid fraction in the thallus. Sorption isotherm fitted to NMR data showed the absence of ‘sealed’ water fraction trapped in pores of the thallus.