bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crossing numbers of imbalanced graphs
Authors: Pach János , Solymosi József , Tardos Gábor 
Published: August 2009

AbstractThe crossing number, cr(G), of a graph G is the least number of crossing points in any drawing of G in the plane. According to the Crossing Lemma of M. Ajtai, V. Chvátal, M. Newborn, E. Szemerédi, Theory and Practice of Combinatorics, North‐Holland, Amsterdam, New York, 1982, pp. 9–12 and F. T. Leighton, Complexity Issues in VLSI, MIT Press, Cambridge, 1983, the crossing number of any graph with n vertices and e>4n edges is at least constant times e3/n2. Apart from the value of the constant, this bound cannot be improved. We establish some stronger lower bounds under the assumption that the distribution of the degrees of the vertices is irregular. In particular, we show that if the degrees of the vertices are d1⩾d2⩾···⩾dn, then the crossing number satisfies with , and that this bound is tight apart from the values of the constants c1, c2>0. Some applications are also presented. © 2009 Wiley Periodicals, Inc. J Graph Theory 64: 12–21, 2010
The influence of authentic leadership behaviors on trust and work outcomes of health care staff
Authors: Wong Carol A. , Cummings Greta G. 
Published: August 2009

AbstractA key element of a healthy work environment is trust: trust between staff and their leaders. Authentic leadership is proposed as the core of effective leadership needed to build trust because of its clear focus on the positive role modeling of honesty, integrity, and high ethical standards in the development of leader‐follower relationships. A model linking authentic leadership behaviors with trust in management, perceptions of supportive groups and work outcomes (including voice or speaking‐up behavior, self‐rated job performance, and burnout) using secondary analysis procedures was examined. The hypothesized model was tested using structural equation modeling in two samples of health care employees from a western Canadian cancer care agency: clinical care providers including nurses, pharmacists, physicians, and other professionals (N = 147) and nonclinical employees including administrative, support, and research staff (N = 188). Findings suggest that supportive leader behavior and trust in management are necessary for staff to be willing to voice concerns and offer suggestions to improve the workplace and patient care.
Teaching theory: A response to Nelson, Henry, Holcomb, Guajardo, and Jenlink
Authors: Waite Duncan 
Published: August 2009

AbstractAn act of leadership is always an act of practical theory. We lead because we hold visions of the world as it ought to be, because of the not yet, because of the potential that we see in ideas and people. Yet, there still exists a perceived binary between leadership theory (in the strong sense) and leadership practice, a binary that divides organizations, classrooms, and the differing bodies of leadership literature. In this Symposium, Duncan Waite and his colleagues discuss the barriers they have faced in bringing theory to the educational leadership classroom, as well as the promise they feel theory holds for more productive, equitable, and humane schooling organizations.
The Holocene volcanic history of Gran Canaria island: implications for volcanic hazards
Authors: Rodriguez‐Gonzalez Alejandro , Fernandez‐Turiel Jose L. , Perez‐Torrado Francisco J. , Hansen Alex , Aulinas Meritxell , Carracedo Juan C. , Gimeno Domingo , Guillou Hervé , Paris Raphaël , Paterne Martine 
Published: August 2009

AbstractPrevious published data, combined with our results of 13 new radiocarbon ages and extensive geological fieldwork, indicate that during the past 11 ka 24 monogenetic basaltic eruptions occurred in the north sector of Gran Canaria. These eruptions can be grouped into three periods of eruptive activity: 1900–3200 14C a BP; 5700–6000 14C a BP; and an older period represented by only one eruption, El Draguillo, dated at 10 610 ± 190 14C a BP. Archaeological studies have shown that the more recent eruptions affected prehistoric human settlements on the island. Field studies demonstrate that the eruptions typically built strombolian cones (30–250 m in height) and associated relatively long lava flows (100–10 350 m in length); a few eruptions also produced tephra fall deposits. The total erupted volume of these eruptions is about 0.388 km3 (46.1% as tephra fall, 41.8% as cinder cone deposits and 12.1% as lava flows). The relatively low eruption rate (∼0.04 km3 ka−1) during the past 11 ka is consistent with Gran Canaria's stage of evolution in the regional volcano‐tectonic setting of the Canary Archipelago. The results of our study were used to construct a volcanic hazards map that clearly delimits two sectors in the NE sector of Gran Canaria, where potential future eruptions would pose a substantial risk for densely populated areas. Copyright © 2009 John Wiley & Sons, Ltd.
Consistent grain size distribution of pedogenic maghemite of surface soils and Miocene loessic soils on the Chinese Loess Plateau
Authors: Nie Junsheng , Song Yougui , King John W. , Egli Ramon 
Published: August 2009

AbstractThere is agreement that ultrafine maghemite grains (<100 nm) are responsible for the magnetic enhancement of Chinese loess. Recent studies show that grain size distribution of ultrafine pedogenic maghemite grains within the aeolian sequences on the central Chinese Loess Plateau deposited in the last 8 Ma is consistent. However, whether the observed grain size distribution of ultrafine pedogenic maghemite grains can be observed in the western Chinese Loess Plateau and modern soils is not entirely clear. Here we find that young surface soil samples across the Chinese Loess Plateau and early Neogene loessic soils from the western Chinese Loess Plateau also show consistent grain size distribution with that of ultrafine pedogenic maghemite grains on the central Chinese Loess Plateau. The fact that young surface soil samples show apparent magnetic enhancement suggests that the ultrafine pedogenic maghemite grains derive from oxidation of ultrafine magnetite grains. Copyright © 2009 John Wiley & Sons, Ltd.
Micro‐Raman and portable Raman spectroscopic investigation of blue pigments in selected Delft plates (17–20th Century)
Authors: de Waal D. 
Published: August 2009

AbstractThe blue pigment as well as other materials in a blue, white and ‘gold’ 17th century Delft dish were analysed and compared to the blue pigment(s) used in a modern blue‐and‐white Delft dish, obtained from a tourist shop in Amsterdam in 2004. The ancient Delft blue pigment was compared to a commercial Delft blue powder identified as a cobalt‐doped willemite, Zn2−xCoxSiO4. The 17th century Delft pigment showed a closer correspondence to the olivine, alpha‐cobalt silicate. The pigment in the modern blue Delft dish was mainly a vanadium‐doped zircon, ZrSiO4:V4+, with small amounts of cobalt, identified by EDX analysis. The cobalt compound could, however, not be characterised here for the modern dish. The pigment in the ‘golden’ rim was identified as pyrochlore yellow, PbSnSbO6.5. Copyright © 2009 John Wiley & Sons, Ltd.
Factors affecting the service quality of the tour guiding profession in Macau
Authors: Mak Athena H. N. , Wong Kevin K. F. , Chang Richard C. Y. 
Published: August 2009

AbstractThis study examines the factors affecting the service quality of the tour guiding profession in Macau. In‐depth interviews were conducted with representatives from the Macau Tourist Guide Association, the Macau Government Tourist Office and selected practising tour guides to explore the issues from multiple insiders' perspectives. The factors identified were classified into six categories: unhealthy business practices, market domination, immaturity of tourist market, changing tourist behaviour, intense competition between inbound tour operators and human resource issues. The findings suggest that a number of these problems actually originated from the unhealthy business practices of the tourist‐generating country, namely mainland China in this study. Considering the growing importance of the Chinese outbound tourism market, the study findings will be of significant value to Macau and to other destinations targeting the Chinese market. Copyright © 2009 John Wiley & Sons, Ltd.
Studies on the oxygen atom transfer reactions of peroxomonosulfate: Catalytic effect of hemiacetal
Authors: Shailaja S. , Ramachandran M. S. 
Published: August 2009

AbstractThe reaction of peroxomonosulfate (PMS) with glycolic acid (GLYCA), an alpha hydroxy acid, in the presence of Ni(II) ions and formaldehyde was studied in the pH range 4.05–5.89 and at 31°C and 38°C. When formaldehyde and Ni(II) ions concentrations are ∼5.0 × 10−4 M to 10.0 × 10−4 M, the reaction is second order in PMS concentration. The rate is catalyzed by formaldehyde, and the observed rate equation is (−d[PMS])/dt = (k′2[HCHO][Ni(II)][PMS]2)/{[H+](1+K2[GLYCA])}. The number of PMS decomposed for each mole of formaldehyde (turnover number) is 5–10, and the major reaction product is oxygen gas. The first step of the reaction mechanism is the formation of hemiacetal by the interaction of HCHO with the hydroxyl group of nickel glycolate. The peroxomonosulfate intermediate of the Ni‐hemiacetal reacts with another molecule of PMS in the rate‐limiting step to give the product. This reaction is similar to the thermal decomposition of PMS catalyzed by Ni(II) ions. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 642–649, 2009
Copper corrosion in drinking water systems – effect of pH and phosphate‐dosage
Authors: Dartmann J. , Sadlowsky B. , Dorsch T. , Johannsen K. 
Published: August 2009

AbstractCopper corrosion in residential plumbing installations can lead to an increase in copper concentration in drinking water as well as to leakages. Central water treatment steps such as pH‐adjustment or dosages of phosphate‐based inhibitors are measures in reducing copper corrosion. Especially phosphate in drinking water is believed to work as a corrosion inhibitor, but it is currently uncertain as to how this inhibitor works. In some cases the phosphate dosage aggravated the copper corrosion. The mechanisms are not yet clear and the influence of phosphate and pH remain a question to be answered. The results of a German Gas and Water Works Association (DVGW) research project on copper corrosion are presented as follows. The influence and the mechanisms of decarbonisation, deacidification and phosphate dosing on copper release in residential plumbing installations were studied in pipe rig experiments according to the German standard DIN 50931‐1. It shows that an increased pH‐value can lead to a decrease in copper content and that a phosphate dosage can lead to both higher and lower copper concentrations.
Influence of Layered Double Hydroxides on the Curing of Carboxylated Nitrile Rubber with Zinc Oxide
Authors: Thakur Varun , Das Amit , Mahaling Ram N. , Rooj Sandip , Gohs Uwe , Wagenknecht Udo , Heinrich Gert 
Published: August 2009

AbstractUnmodified (LDH) and modified (mLDH) layered double hydroxides have been added to gum and ZnO‐cured carboxylated nitrile rubber (XNBR). It was observed that both LDH and mLDH inhibit the formation of ionic cross‐links between XNBR and ZnO quite significantly, as is evident from DMA and FT‐IR studies. The suppression of ionic cross‐links formation was also reflected in the mechanical properties of the resulting composites. A tentative sketch has also been suggested for the possible mechanism involved in the inhibition of ionic cross‐links by LDHs. X‐ray diffraction and STEM studies were performed to see the dispersion of LDH's in the elastomer matrix.magnified image
Novel Absorbent Materials Created via Ice Templating
Authors: Gawryla Matthew D. , Schiraldi David A. 
Published: August 2009

AbstractIce‐templated aerogels made from water soluble/dispersible raw materials are formed through an environmentally friendly freeze‐drying process. The structures that result from ice templating are capable of absorbing liquids into their large void volume. The effects of polymer chemistry and material loading on the absorption into the dried materials are studied. Low‐density samples were able to absorb liquids rapidly but the liquid‐saturated structures lacked mechanical integrity. The higher‐density samples absorbed liquids more slowly and again retained little structural integrity. The addition of fibers and firing of low‐density clay aerogels into ceramics provide multiple routes to creating structures exhibiting rapid absorption and a rigid, stable structure when saturated.magnified image
New Light on Old Wisdoms on Molten Polymers: Conformation, Slippage and Shear Banding in Sheared Entangled and Unentangled Melts
Authors: Noirez Laurence , Mendil‐Jakani Hakima , Baroni Patrick 
Published: August 2009

AbstractThe flow of viscoelastic materials is usually interpreted as resulting from intramolecular properties. Typically, the non‐linear flow behaviour and sluggish relaxation dynamics in entangled polymers are interpreted by a disentanglement process. This molecular interpretation has never been validated by direct observation. We report here on in situ observations of polymer melts under steady‐state shear flow using neutron scattering and particle tracking velocimetry. It is shown that the chains remain largely undeformed under steady‐state shear flow whereas wall slippage and shear‐banding are identified in both entangled and unentangled polymer melts. These observations are of prime importance; they reveal that the flow mechanism and its viscoelastic signature reflect a collective effect and not properties of individual chains.magnified image
Color‐Oscillating Photonic Crystal Hydrogel
Authors: Tian Entao , Ma Ying , Cui Liying , Wang Jingxia , Song Yanlin , Jiang Lei 
Published: August 2009

AbstractIn this work, a color‐oscillating system is first developed by combining the intrinsic peristaltic motion of a Landolt pH‐oscillator with the structure color of a well‐designed pH‐sensitive photonic crystal hydrogel. As a result, the pH oscillation reaction procedure could be distinctly monitored by the distinct change of structure color/optic signal. The oscillation rhythm of the pH well coincides with that of the stopband/structure color. The oscillation detail of each cycle can also be clearly monitored by color change. This work would be of great significance for the promising applications of real‐time monitoring of the microactuator by optical signal or structure color.magnified image
Ultra‐Fast RAFT‐HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers
Authors: Inglis Andrew J. , Stenzel Martina H. , Barner‐Kowollik Christopher 
Published: August 2009

AbstractThe use of the reversible addition fragmentation chain transfer—hetero Diels–Alder (RAFT‐HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end‐functionalized polystyrene (PS‐Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well‐defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol−1 and with small polydispersities (PDI < 1.2). The conjugation reactions proceeded in a very rapid fashion (less than 10 min in the majority of cases) under ambient conditions of temperature and atmosphere. The present study demonstrates—for the first time—that RAFT‐HDA click chemistry can provide access to high molecular weight block copolymers in a simple and straight‐forward fashion.magnified image
Theoretical Postulation of Mass Spectral Quantity and Distribution in Competitive Dynamic Dendrimer Mixtures
Authors: Leung Ken Cham‐Fai 
Published: August 2009

AbstractThe theoretical postulations of mass spectral quantities and distributions of the three dynamic combinatorial libraries (DCLs) of mechanically interlocked dendrimers ([4]rotaxanes, molecular weight up to 8 800 kDa) have been investigated. The number of different dendrimers in the three library mixtures is 4, 10, and 20. The theoretical postulations involve their macroconstants in a combination with statistical distribution, binding constant, steric, and hydrophobic effects. We found out that the mass spectral intensities which relate to the dendrimer quantities in a competitive mixture are not random, but with a predictable trend in terms of their macroconstants. This postulation agrees significantly well with most of the experimentally determined mass spectral intensities in the dendrimer mixtures.magnified image
Brain dopaminergic modulation associated with executive function in Parkinson's disease
Authors: Farid Karim , Sibon Igor , Guehl Dominique , Cuny Emmanuel , Burbaud Pierre , Allard Michèle 
Published: August 2009

AbstractThe progressive development of deficits in executive functions, including action planning, is a well‐known complication of Parkinson's disease. A dysfunction of the prefrontal lobe, which is known to be involved in the control of inhibitory processes, could explain the difficulties in initiating behavior or inhibiting ongoing actions in patients with PD. The strong dopaminergic innervation of the prefrontal cortex raises questions about the putative effects of dopa therapy on this cognitive impairment. In the present study, we used fMRI to examine the functional influence of dopa therapy on neural activity during a go/no‐go task in nine patients with and without levodopa treatment and in matched controls. Whereas the patient and control subjects exhibited the same performance during the go/no‐go task, different patterns of brain activation were observed depending on the dopaminergic status. The drug‐off state was characterized by more widely distributed brain activity, mainly in the bilateral caudate. Levodopa did not fully restore normal brain activation and induced changes in the pattern of cingulate cortex activity, which was more pronounced in the rostral part in the drug‐off state and in the caudal part after levodopa intake. These results support the idea of a critical role for dopamine in the control of executive functions in patients with PD. © 2009 Movement Disorder Society
Analysis of SCA2 and SCA3/MJD repeats in Parkinson's disease in mainland China: Genetic, clinical, and positron emission tomography findings
Authors: Wang Jun‐Ling , Xiao Bin , Cui Xiang‐Xiang , Guo Ji‐Feng , Lei Li‐Fang , Song Xing‐Wang , Shen Lu , Jiang Hong , Yan Xin‐Xiang , Pan Qian , Long Zhi‐Gao , Xia Kun , Tang Bei‐Sha 
Published: August 2009

AbstractTo investigate the prevalence and clinical feature(s) of Parkinson's disease (PD) patients with expanded (ATXN2 and MJD1) genes of spinocerebellar ataxia type 2 and 3 (SCA2 and SCA3/MJD) in a mainland Chinese population, CAG triplet repeat expansions of (SCA2 and SCA3/MJD) genes (ATXN2 and MJD1) were analyzed in a cohort of 452 PD patients, including 386 sporadic and 66 familial forms. Striatal dopamine transporter was evaluated in two SCA2 and two SCA3/MJD‐positive family members, an idiopathic PD patient and a healthy control using carbon (C11) [11C]‐radiolabeled‐CFT positron emission tomography (PET). We found two patients in one familial PD (FPD) family (1.5%) and two sporadic PD patients (0.5%) with expanded CAG repeats in the ATXN2 locus, four patients in two FPD families (3%) and another three sporadic PD patients (0.8%) in the MJD1 locus. [11C]‐CFT PET in detected members in SCA2 and SCA3/MJD families showed decrements of 11C‐CFT uptake. These findings suggest that a mutation in SCA2 or SCA3/MJD may be one of the genetic causes of PD. © 2009 Movement Disorder Society
Fatigue in Japanese patients with Parkinson's disease: A study using Parkinson fatigue scale
Authors: Okuma Yasuyuki , Kamei Satoshi , Morita Akihiko , Yoshii Fumihito , Yamamoto Toshimasa , Hashimoto Shiori , Utsumi Hiroya , Hatano Taku , Hattori Nobutaka , Matsumura Miyuki , Takahashi Kazushi , Nogawa Shigeru , Watanabe Yuka , Miyamoto Tomoyuki , Miyamoto Masayuki , Hirata Koichi 
Published: August 2009

AbstractThe objective of this multicenter cross‐sectional study was to determine the prevalence of fatigue and factors contributing to it in a large sample of Japanese patients with Parkinson's disease (PD). We used the 16‐item Parkinson Fatigue Scale (PFS‐16), which was designed to assess fatigue exclusively associated with PD. We carried out this study using PFS‐16, the Unified Parkinson's Disease Rating Scale, Zung's Self‐Rating Depression Scale, Parkinson's Disease Sleep Scale (PDSS), and the PD quality of life (QOL) scale (PDQ‐39) by interview using questionnaires and physical examination by neurologists in 361 nondemented PD patients. Fatigue (an average PFS score of 3.3 or greater) was revealed in 151 patients (41.8%). Multiple logistic regression analysis indicated that the significant independent variables related to the presence of fatigue were the scores of PDSS and PDQ‐39. Depression score was not a significant contributing factor. Our study revealed that the prevalence of fatigue in Japanese PD patients is as high as that in Western countries, and that fatigue is a relatively independent symptom, although sleep disturbance may be associated with fatigue. Since fatigue is significantly related to QOL reduction, therapeutic interventions including treatment of sleep disturbance are important. © 2009 Movement Disorder Society
Spiral analysis in Niemann‐Pick disease type C
Authors: Hsu Annie W. , Piboolnurak Panida A. , Floyd Alicia G. , Yu Qiping P. , Wraith James E. , Patterson Marc C. , Pullman Seth L. 
Published: August 2009

AbstractSpiral analysis is a computerized method of analyzing upper limb motor physiology through the quantification of spiral drawing. The objective of this study was to determine whether spirals drawn by patients with Niemann‐Pick disease type C (NPC) could be distinguished from those of controls, and to physiologically characterize movement abnormalities in NPC. Spiral data consisting of position, pressure, and time were collected from 14 NPC patients and 14 age‐matched controls, and were analyzed by the Mann‐Whitney U test. NPC spirals were characterized by: lower speed (2.67 vs. 9.56 cm/s, P < 0.001) and acceleration (0.10 vs. 2.04 cm/s2, P < 0.001), higher loop width variability (0.88 vs. 0.28, P < 0.001), tremor (5/10 vs. 0/10 trials in the dominant hand, P < 0.001), and poor overall spiral rating (2.53 vs. 0.70, P < 0.005). NPC spirals also exhibited sustained drawing pressure profiles that were abnormally invariant with time. Other features, such as the tightness of loop widths, were normal. Our findings reveal that differing aspects of tremor, Parkinsonism, ataxia, and dystonia are quantifiable in NPC patients. © 2009 Movement Disorder Society
On the solutions of a class of iterated generalized Bers–Vekua equations in Clifford analysis
Authors: Berglez P. 
Published: August 2009

AbstractWe consider functions with values in the Clifford algebra Clp,q which are solutions of a certain class of the iterated generalized Bers–Vekua equation Dmw=0 with Dw=∂w+cw̄ where \documentclass{article}\usepackage{amssymb}\usepackage{amsbsy}\usepackage[mathscr]{euscript}\footskip=0pc\pagestyle{empty}\begin{document}$\partial={\sum\nolimits_{j=0}^{n}}e_j\,\partial/{\partial x_j}$\end{document} is the generalized Cauchy–Riemann operator and x=x0+x1e1+…xnen. We prove that any such function w has an Almansi‐type decomposition of the form w=v0+x0v1+···+xvm−1 where the functions vj, j=0,1,…, m−1, are solutions of the generalized Bers–Vekua equation Dv=0. Copyright © 2009 John Wiley & Sons, Ltd.
Biregular extendability via isotonic Clifford analysis
Authors: Blaya Ricardo Abreu , Reyes Juan Bory , Peña Dixan Peña , Sommen Frank 
Published: August 2009

AbstractWe use the so‐called isotonic functions to obtain extension theorems in the framework of biregular functions of Clifford analysis. In this context we also prove the Plemelj–Sokhotski formulae for the Bochner–Martinelli integral and an expression for the square of its singular version. Copyright © 2009 John Wiley & Sons, Ltd.