bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rainbow connection number and connected dominating sets
Authors: Sunil Chandran L. , Das Anita , Rajendraprasad Deepak , Varma Nithin M. 
Published: December 2011

AbstractThe rainbow connection number of a connected graph is the minimum number of colors needed to color its edges, so that every pair of its vertices is connected by at least one path in which no two edges are colored the same. In this article we show that for every connected graph on n vertices with minimum degree δ, the rainbow connection number is upper bounded by 3n/(δ + 1) + 3. This solves an open problem from Schiermeyer (Combinatorial Algorithms, Springer, Berlin/Hiedelberg, 2009, pp. 432–437), improving the previously best known bound of 20n/δ (J Graph Theory 63 (2010), 185–191). This bound is tight up to additive factors by a construction mentioned in Caro et al. (Electr J Combin 15(R57) (2008), 1).As an intermediate step we obtain an upper bound of 3n/(δ + 1) − 2 on the size of a connected two‐step dominating set in a connected graph of order n and minimum degree δ. This bound is tight up to an additive constant of 2. This result may be of independent interest.We also show that for every connected graph G with minimum degree at least 2, the rainbow connection number, rc(G), is upper bounded by Γc(G) + 2, where Γc(G) is the connected domination number of G. Bounds of the form diameter(G)⩽rc(G)⩽diameter(G) + c, 1⩽c⩽4, for many special graph classes follow as easy corollaries from this result. This includes interval graphs, asteroidal triple‐free graphs, circular arc graphs, threshold graphs, and chain graphs all with minimum degree at least 2 and connected. We also show that every bridge‐less chordal graph G has rc(G)⩽3·radius(G). In most of these cases, we also demonstrate the tightness of the bounds.
The potential of greed for independence
Authors: Borowiecki Piotr , Göring Frank , Harant Jochen , Rautenbach Dieter 
Published: December 2011

AbstractThe well‐known lower bound on the independence number of a graph due to Caro (Technical Report, Tel‐Aviv University, 1979) and Wei (Technical Memorandum, TM 81 ‐ 11217 ‐ 9, Bell Laboratories, 1981) can be established as a performance guarantee of two natural and simple greedy algorithms or of a simple randomized algorithm. We study possible generalizations and improvements of these approaches using vertex weights and discuss conditions on so‐called potential functions pG: V(G)→ℕ0 defined on the vertex set of a graph G for which suitably modified versions of the greedy algorithms applied to G yield independent sets I with . We provide examples of such potentials, which lead to bounds improving the bound due to Caro and Wei. Furthermore, suitably adapting the randomized algorithm we give a short proof of Thiele's lower bound on the independence number of a hypergraph (T. Thiele, J Graph Theory 30 (1999), 213–221).
The structure of 4‐strong tournaments containing exactly three out‐arc pancyclic vertices
Authors: Guo Qiaoping , Li Shengjia , Li Ruijuan 
Published: December 2011

AbstractYao et al. (Discrete Appl Math 99 (2000), 245–249) proved that every strong tournament contains a vertex u such that every out‐arc of u is pancyclic and conjectured that every k‐strong tournament contains k such vertices. At present, it is known that this conjecture is true for k = 1, 2, 3 and not true for k⩾4. In this article, we obtain a sufficient and necessary condition for a 4‐strong tournament to contain exactly three out‐arc pancyclic vertices, which shows that a 4‐strong tournament contains at least four out‐arc pancyclic vertices except for a given class of tournaments. Furthermore, our proof yields a polynomial algorithm to decide if a 4‐strong tournament has exactly three out‐arc pancyclic vertices.
Late Pleistocene palaeolake in the interior of Oman: a potential key area for the dispersal of anatomically modern humans out‐of‐Africa?
Authors: Rosenberg Thomas M. , Preusser Frank , Blechschmidt Ingo , Fleitmann Dominik , Jagher Reto , Matter Albert 
Published: December 2011

AbstractRelict fluvial and lacustrine deposits in the interior of Oman near Saiwan consist of waterlain breccias with pebble imbrications and current ripples, covered by algal laminites containing calcified reeds and charcoal pieces. Geomorphological evidence suggests that the palaeolake covered a maximum surface of 1400 km2 and had a maximum depth of about 25 m. Optically stimulated luminescence (OSL) and thermally transferred OSL dating indicate that this palaeolake existed sometime between 132 and 104 ka. The rich archaeological evidence in the area suggests substantial human occupation, possibly at the time when Palaeolake Saiwan existed. Interestingly, the lithic traditions of the archaeological material show no clear relation to coeval findings from neighbouring areas, putting a question mark on the origin of the culture found at Saiwan. This finding raises questions concerning the origin of the population inhabiting Saiwan, as the site lies along one possible route for the dispersal of anatomically modern humans out‐of‐Africa. Copyright © 2011 John Wiley & Sons, Ltd.
Current and projected abundance of potential nest sites for cavity‐nesting ducks in hardwoods of the north central United States
Authors: Denton John C. , Roy Charlotte L. , Soulliere Gregory J. , Potter Bradly A. 
Published: December 2011

AbstractClearing of hardwood forests was widespread in the north central region of the United States at the turn of the 20th century, but largely subsided by the 1920s. Hardwood trees in the region have since regenerated and matured into sizes capable of producing nest cavities suitable for cavity‐nesting ducks. We estimated regional nest‐site abundance for cavity‐nesting ducks during 2008, 2018, and 2028 from cavity density and tree‐abundance estimates obtained at 4 hardwood forest sites in conjunction with Forest Inventory and Analysis data and tree‐growth modeling software from the United States Forest Service (Forest Vegetation Simulator). Land cover data were used to determine area of hardwood forests ≤0.5 km, 0.5–1 km, 1–1.5 km, 1.5–2 km, and >2 km from wetlands and open water available to cavity‐nesting ducks. We estimated 13.2 million, 17.0 million, 19.0 million, and 20.1 million potential duck nest cavities available ≤0.5 km, ≤1 km, ≤1.5 km, and ≤2 km of water, respectively, in the region and predicted nest cavity abundance will increase 41% from 2008 to 2028. Hardwood forests in Indiana, Michigan, Ohio, and Wisconsin currently have the highest abundances of potential nest sites, but cavity‐bearing forests in Minnesota, Michigan, and Wisconsin were more commonly proximate to wetlands and open water. Because current and future estimates indicate sufficient nest sites to support growing cavity‐nesting duck populations in the north central United States, we recommend regional management efforts focus on protecting, restoring, and maintaining quality wetlands in proximity to hardwood forests. © 2011 The Wildlife Society.
Tunable Morphologies From Bulk Self‐Assemblies of Poly(acryloxypropyl triethoxysilane)‐b‐poly(styrene)‐b‐poly(acryloxypropyl triethoxysilane) Triblock Copolymers
Authors: Gamys Cé Guinto , Beyou Emmanuel , Bourgeat‐Lami Elodie , David Laurent , Alcouffe Pierre 
Published: December 2011

AbstractReactive poly(acryloxypropyl triethoxysilane)‐b‐poly(styrene)‐b‐poly(acryloxypropyl triethoxysilane) (PAPTES‐b‐PS‐b‐PAPTES) triblock copolymers are prepared through nitroxide‐mediated polymerization (NMP). The bulk morphologies formed by this class of copolymers cast into films are examined by small‐angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM). The films morphology can be tuned from spherical structures to lamellar structures by increasing the volume fraction of PS in the copolymer. Thermal annealing at temperatures above 100 °C provides sufficient PS mobility to improve ordering.
Three‐Dimensionally Ordered Macroporous Nitroxide Polymer Brush Electrodes Prepared by Surface‐Initiated Atom Transfer Polymerization for Organic Radical Batteries
Authors: Lin Chun‐Hao , Chou Wei‐Jen , Lee Jyh‐Tsung 
Published: December 2011

AbstractThe synthesis and electrochemical performance of three‐dimensionally ordered macroporous (3DOM) nitroxide polymer brush electrodes for organic radical batteries are reported. The 3DOM electrodes are synthesized via polystyrene colloidal crystal templating with electropolymerization of polypyrrole, modification of surface initiator, and surface‐initiated atom transfer radical polymerization. The discharge capacity of the 3DOM electrodes is proportional to the thickness of the inverse opal. The discharge capacity of the 3DOM electrode at a discharge rate of 5 C is 40 times higher than that of the planar electrode; its cycle‐life performance exhibits 96.1% retention after 250 cycles.
Triblock Copolymer Based on Poly(propylene oxide) and Poly(1‐[11‐acryloylundecyl]‐3‐methyl‐imidazolium bromide)
Authors: Texter John , Vasantha Vivek Arjunan , Crombez Rene , Maniglia Rafael , Slater Lisa , Mourey Thomas 
Published: December 2011

AbstractThe controlled atom transfer radical polymerization of an ionic liquid, 1‐(11‐acryloylundecyl)‐3‐methyl imidazolium bromide (ILBr), from both ends of a telechelic poly(propylene oxide) (PPO) macroinitiator, end‐functionalized with bromoisobutyryloyl is reported. The resulting highly water‐soluble triblock, poly(ILBr‐b‐PO‐b‐ILBr) is multistimuli responsive. This new class of triblocks exhibits classical surface activity in lowering surface tension at the air–water interface and in modifying wetting in waterborne coatings. It also immunizes model colloids against coagulation induced by Debye–Hückel (indifferent electrolyte) electrostatic screening. Further, sol–gel thermoreversibility is unexpectedly found as an additional form of stimuli responsiveness.
Direct 3D Visualization of the Phase‐Separated Morphology in Chlorinated Polyethylene/Nylon Terpolyamide Based Thermoplastic Elastomers
Authors: Crisenza Tommaso , Butt Hans‐Jürgen , Koynov Kaloian , Simonutti Roberto 
Published: December 2011

AbstractBlends of chlorinated polyethylene and nylon‐6/‐6,6/‐12 terpolyamide were prepared. The ratio of the two components was systematically varied within the blends. The mechanical behavior of the samples was analyzed with tensile tests and dynamical mechanical analysis showing that, for several ratios, materials with improved mechanical properties typical of thermoplastic elastomers were obtained. In such a mechanical regime, a co‐continuous phase‐separated morphology was clearly evidenced at the microscopic scale by 3D laser scanning confocal fluorescent microscopy (LSCFM). At blend compositions where plastic tensile behavior is observed, LSCFM reveals dispersed spheres of one component in the other.
Toward the Realization of A Practical Diketopyrrolopyrrole‐Based Small Molecule for Improved Efficiency in Ternary BHJ Solar Cells
Authors: Lee Junghoon , Yun Myoung Hee , Kim Jonggi , Kim Jin Young , Yang Changduk 
Published: December 2011

AbstractAn easily accessible DPP‐based small molecule (DMPA‐DTDPP) has been synthesized by a simple and efficient route. The resulting molecule, when incorporated into a P3HT:PCBM‐based BHJ solar cell, is found to significantly improve the efficiency. The utility of DMPA‐DTDPP as an additive yields an increase in the short circuit current density (Jsc) because DMPA‐DTDPP serves as an energy funnel for P3HT excitons at the P3HT:PCBM interfaces, resulting in an improved overall power conversion efficiency, compared to the P3HT:PCBM control device. Considering the trouble‐free and cost effective synthesis of DMPA‐DTDPP, it may prove very useful in high‐performance solar cells.
Optically Active Helical Substituted Polyacetylenes Showing Reversible Helix Inversion in Emulsion and Solution State
Authors: Huang Yingying , Zhang Yuanyuan , Yang Wantai , Deng Jianping 
Published: December 2011

AbstractThis Communication reports two substituted polyacetylenes that can adopt helical structures of preferential screw sense in both emulsion (nanoparticle) and solution; however, the handedness of the macromolecular helices is just opposite in the two states. More interestingly, the helical screw sense of the polymers demonstrated a reversible transition between the two states. The unprecedented findings are of significant importance for acquiring new insights into helical polymers and for developing novel advanced chiral materials.
Diffusion‐prepared fast imaging with steady‐state free precession (DP‐FISP): A rapid diffusion MRI technique at 7 T
Authors: Lu Lan , Erokwu Bernadette , Lee Gregory , Gulani Vikas , Griswold Mark A. , Dell Katherine M. , Flask Chris A. 
Published: December 2011

AbstractDiffusion MRI is a useful imaging technique with many clinical applications. Many diffusion MRI studies have utilized echo‐planar imaging (EPI) acquisition techniques. In this study, we have developed a rapid diffusion‐prepared fast imaging with steady‐state free precession MRI acquisition for a preclinical 7T scanner providing diffusion‐weighted images in less than 500 ms and diffusion tensor imaging assessments in ∼1 min with minimal image artifacts in comparison with EPI. Phantom apparent diffusion coefficient (ADC) and fractional anisotropy (FA) assessments obtained from the diffusion‐prepared fast imaging with steady‐state free precession (DP‐FISP) acquisition resulted in good agreement with EPI and spin echo diffusion methods. The mean apparent diffusion coefficient was 2.0 × 10−3 mm2/s, 1.90 × 10−3 mm2/s, and 1.97 × 10−3 mm2/s for DP‐FISP, diffusion‐weighted spin echo, and diffusion‐weighted EPI, respectively. The mean fractional anisotropy was 0.073, 0.072, and 0.070 for diffusion‐prepared fast imaging with steady‐state free precession, diffusion‐weighted spin echo, and diffusion‐weighted EPI, respectively. Initial in vivo studies show reasonable ADC values in a normal mouse brain and polycystic rat kidneys. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Psychometric evaluation of the myasthenia gravis composite using rasch analysis
Authors: Sadjadi Reza , Conaway Mark , Cutter Gary , Sanders Donald B. , Burns Ted M. ,   the MG Composite MG‐QOL15 Study Group
Published: December 2011

AbstractIntroduction: The MG Composite (MGC) is a validated outcome measure of the clinical manifestations of myasthenia gravis. Methods: We performed Rasch analyses of the MGC to investigate additional properties, including its unidimensionality and the appropriateness of the weights assigned to the response categories for the MGC items. Results: The fit statistics indicated that the 10 items belong together and can be summated for a total score. There was an overall absence of item order distortion between response categories. The Rasch model's expected category response values were compatible with item weights previously assigned. Conclusions: Our analysis suggests that: (1) the score can be summated to estimate an overall disease severity score; (2) the response options of the 10 items are not significantly distorted; and (3) the assigned weights of the response options are appropriate. Muscle Nerve 45: 820–825, 2012
Computation of limit and shakedown loads using a node‐based smoothed finite element method
Authors: Nguyen‐Xuan H. , Rabczuk T. , Nguyen‐Thoi T. , Tran T.N. , Nguyen‐Thanh N. 
Published: December 2011

SUMMARYThis paper presents a novel numerical procedure for computing limit and shakedown loads of structures using a node‐based smoothed FEM in combination with a primal–dual algorithm. An associated primal–dual form based on the von Mises yield criterion is adopted. The primal‐dual algorithm together with a Newton‐like iteration are then used to solve this associated primal–dual form to determine simultaneously both approximate upper and quasi‐lower bounds of the plastic collapse limit and the shakedown limit. The present formulation uses only linear approximations and its implementation into finite element programs is quite simple. Several numerical examples are given to show the reliability, accuracy, and generality of the present formulation compared with other available methods. Copyright © 2011 John Wiley & Sons, Ltd.
Anisotropic mixed finite elements for elasticity
Authors: Pechstein A. , Schöberl J. 
Published: December 2011

SUMMARYIn this paper, we present a family of mixed finite elements, which are suitable for the discretization of slim domains. The displacement space is chosen as Nédélec's space of tangential continuous elements, whereas the stress is approximated by normal–normal continuous symmetric tensor‐valued finite elements. We show stability of the system on a slim domain discretized by a tensor product mesh, where the constant of stability does not depend on the aspect ratio of the discretization. We give interpolation operators for the finite element spaces, and thereby obtain optimal order a priori error estimates for the approximate solution. All estimates are independent of the aspect ratio of the finite elements. Copyright © 2011 John Wiley & Sons, Ltd.
PMLs: A direct approach
Authors: Kausel Eduardo , de Oliveira Barbosa João Manuel 
Published: December 2011

SUMMARYThis brief article outlines a new and rather simple method for obtaining the finite element matrices for a perfectly matched layer used for elastic wave propagation in the context of a frequency‐domain formulation. For this purpose, we introduce a fairly mild simplification, which allows applying the stretching functions directly to the mass and stiffness matrices obtained via conventional methods (i.e., elastic elements), a novel strategy that allows circumventing the use of integration via Gaussian quadrature. In essence, the technique proposed herein is equivalent to a direct application of the method of weighted residuals in stretched space, followed by a conversion of the linear dimensions into position‐dependent complex‐values. Most importantly, numerical tests demonstrate that the technique does work as intended, and in fact, splendidly so. Copyright © 2011 John Wiley & Sons, Ltd.
The taboo of cancer: the experiences of cancer disclosure by Iranian patients, their family members and physicians
Authors: Zamanzadeh Vahid , Rahmani Azad , Valizadeh Leila , Ferguson Caleb , Hassankhani Hadi , Nikanfar Ali‐Reza , Howard Fuchsia 
Published: December 2011

AbstractObjectiveThe objective of this study is to describe the experiences of cancer disclosure by Iranian cancer patients, their family members and physicians.MethodsTwenty cancer patients, ten family members and eight physicians participated in this study. Data were collected via semi‐structured, in‐depth interviews and analyzed using qualitative content analysis.ResultsThree categories were identified: cancer avoidance, a climate of non‐disclosure and mutual concern. The findings demonstrated that cancer is a taboo subject and the word cancer, as well as other indicative terms, was rarely used in daily communication. A climate of non‐disclosure predominated because patients were the last to know their diagnosis, they were unaware of their prognosis, and family members and physicians employed strategies to conceal this information. The mutual concern of patients, family members and physicians was the main reason that cancer was not discussed.ConclusionCancer is a taboo subject in Iran that is maintained and reinforced primarily because of the mutual concern of patients, family members and physicians. The first step to address this taboo and inform cancer patients of their diagnosis would be to understand and help mitigate the individual, family and social consequences of disclosure. Copyright © 2011 John Wiley & Sons, Ltd.
Un Abrazo Para La Familia: Providing low‐income Hispanics with education and skills in coping with breast cancer and caregiving
Authors: Marshall Catherine A. , Badger Terry A. , Curran Melissa A. , Koerner Susan Silverberg , Larkey Linda K. , Weihs Karen L. , Verdugo Lorena , García Francisco A. R. 
Published: December 2011

AbstractObjectiveUn Abrazo Para La Familia (A Hug for the Family) is an intervention designed to increase the accessibility of cancer information to low‐income and medically underserved co‐survivors of cancer. Co‐survivors are family members or friends of an individual diagnosed with cancer. Our goal was to increase socio‐emotional support for these co‐survivors and improve skills in coping with cancer. The purpose of our pilot study was to explore the effectiveness of the intervention in increasing cancer knowledge and self‐efficacy among co‐survivors.MethodsUn Abrazo consisted of three one‐hour sessions, in either Spanish or English. Sessions were delivered by a trained promotora (community health worker), in partnership with a counselor. Sixty participants completed measures of cancer knowledge and self‐efficacy preceding (pre‐test) and following the intervention (post‐test).ResultsFrom pre‐test to post‐test, the percentage of questions answered correctly about cancer knowledge increased (p < 0.001), as did ratings of self‐efficacy (p < 0.001). Decreases were seen in ‘Do not know’ responses for cancer knowledge (p < 0.01), with a negative correlation between number of ‘Do not knows’ on cancer knowledge at pre‐test and ratings of self‐efficacy at pre‐test (r = −0.47, p < 0.01).ConclusionsWhen provided an accessible format, co‐survivors of cancer from underserved populations increase their cancer knowledge and self‐efficacy. This is notable because research indicates that family members and friends with increased cancer knowledge assume more active involvement in the cancer care of their loved ones. Copyright © 2011 John Wiley & Sons, Ltd.
Multi‐agent rotating consensus without relative velocity measurements in three‐dimensional space
Authors: Yang Tan , Jin Yuehui 
Published: December 2011

SUMMARYIn this paper, we study distributed rotating consensus in networks of second‐order agents using only local position information in three‐dimensional space. We propose a protocol to make the multi‐agent system finally move together around a common point and present corresponding conditions for rotating consensus of the system. Finally, a numerical example is provided to demonstrate the effectiveness of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.
Computational models for the study of heart–lung interactions in mammals
Authors: Ben‐Tal Alona 
Published: December 2011

AbstractThe operation and regulation of the lungs and the heart are closely related. This is evident when examining the anatomy within the thorax cavity, in the brainstem and in the aortic and carotid arteries where chemoreceptors and baroreceptors, which provide feedback affecting the regulation of both organs, are concentrated. This is also evident in phenomena such as respiratory sinus arrhythmia where the heart rate increases during inspiration and decreases during expiration, in other types of synchronization between the heart and the lungs known as cardioventilatory coupling and in the association between heart failure and sleep apnea where breathing is interrupted periodically by periods of no‐breathing. The full implication and physiological significance of the cardiorespiratory coupling under normal, pathological, or extreme physiological conditions are still unknown and are subject to ongoing investigation both experimentally and theoretically using mathematical models. This article reviews mathematical models that take heart–lung interactions into account. The main ideas behind low dimensional, phenomenological models for the study of the heart–lung synchronization and sleep apnea are described first. Higher dimensions, physiology‐based models are described next. These models can vary widely in detail and scope and are characterized by the way the heart–lung interaction is taken into account: via gas exchange, via the central nervous system, via the mechanical interactions, and via time delays. The article emphasizes the need for the integration of the different sources of heart–lung coupling as well as the different mathematical approaches.WIREs Syst Biol Med2012, 4:163–170. doi: 10.1002/wsbm.167This article is categorized under:Models of Systems Properties and Processes > Organismal Models