bluuebunny/crossref_metadata_2025 huggingface dataset:
Carboxymethyl chitosan‐coated capillary and its application in CE of proteins
Authors: Fu Xiaofang , Huang Ling , Gao Fei , Li Wei , Pang Nannan , Zhai Maolin , Liu Huwei , Wu Moutian
Published: May 2007

A hydrophilic basic polysaccharide, carboxymethyl chitosan (CMC) as a capillary coating is presented with a simple preparation procedure. The CMC‐coated capillary showed a long lifetime of more than 100 runs, and had good tolerance to some organic solvents, 0.1 M HCl, 0.1 M NaOH, and 5 M urea. The run‐to‐run, day‐to‐day, and capillary‐to‐capillary RSDs for the CMC‐coated capillary were all below 2.0% for the determination of EOF. Moreover, the coatings with different concentrations and molecular weights of CMC were also investigated. The CMC‐coated capillary was successfully applied to separate basic proteins and recombinant human erythropoietin (rhEPO). Furthermore, several experimental parameters, such as the concentration and pH of the running buffer, temperature, and applied voltage, were optimized for the separation of rhEPO glycoforms. Comparison of an uncoated capillary with chitosan‐ and CMC‐coated capillaries for the separation of rhEPO glycoforms was also discussed. The results demonstrated that rhEPO glycoforms can be well separated by a CMC‐coated capillary within 8 min with good reproducibility and resolution. Finally, the volatile BGE HAc‐NH4Ac was utilized to separate rhEPO for its further application with CE‐MS, achieving a satisfactory result.
Subtoxic N‐methyl‐D‐aspartate delayed neuronal death in ischemic brain injury through TrkB receptor‐ and calmodulin‐mediated PI‐3K/Akt pathway activation
Authors: Xu Jing , Zhang Quan‐Guang , Li Chong , Zhang Guang‐Yi
Published: May 2007

Previous studies have shown that subtoxic NMDA moderated the neuronal survival in vitro and vivo. We performed this experiment to clarify the precise mechanism underlie subtoxic NMDA delayed neuronal death in ischemic brain injury. We found that pretreatment of NMDA (100 mg/kg) increased the number of the surviving CA1 pyramidal cells of hippocampus at 5 days of reperfusion. This dose of NMDA could also enhance Akt activation after ischemia/reperfusion (I/R). Here, we examined the possible mechanism that NMDA induced Akt activation. On the one hand, we found NMDA receptor‐mediated Akt activation was associated with increased expression of BDNF (brain‐derived neurotrophic factor) and activation of its high‐affinity receptor TrkB after I/R in the hippocampus CA1 region, which could be held down by TrkB receptor antagonist K252a. On the other hand, we found that NMDA enhanced the binding of Ca2+‐dependent calmodulin (CaM) to p85 (the regulation subunit of PI‐3K), which led to the activation of Akt. W‐13, an active CaM inhibitor, prevented the combination of CaM and p85 and subsequent Akt activation. Furthermore, NMDA receptor‐mediated Akt activation was reversed by combined treatment with LY294002, the specific blockade of PI‐3K. Taken together, our results suggested that subtoxic NMDA exerts the neuroprotective effect via activation of prosurvival PI‐3K/Akt pathway against ischemic brain injury, and BDNF‐TrkB signaling and Ca2+‐dependent CaM cascade might contribute to NMDA induced activation of PI‐3K/Akt pathway. © 2007 Wiley‐Liss, Inc.
Determinants of a merger in a publicly‐funded health system: A political‐economy perspective
Authors: Denis Jean‐Louis , Champagne François , Contandriopoulos André‐Pierre , Cazale Linda
Published: May 2007

This article reports the results of a case study, spanning a period of 10 years, of the merger of two hospitals in a publicly‐funded health system. A political economy model was used to analyse the determinants of the merger. Results show that external political economy factors, mainly pressure from the state to rationalize health services and the organization's needs to acquire critical resources, significantly contributed to the merger decision. At the internal political economy level, groups and individual strategies also played a determinant role. Our study suggests that merger in the public sector may not necessarily result from efficiency motives.
Managing externally‐assisted health projects for sustainability in developing countries
Authors: Stefanini Angelo , Ruck Nicola
Published: May 2007

One of the main problems related to donor‐supported health projects in the developing world is their lack of sustainability once external assistance has ended. Although ‘projectized development assistance’ is viewed by many as inappropriate to bring about development, projects are bound to remain for some time an important instrument of development assistance. Project managers, donor agencies and recipient countries need to be aware of the extent that their projects are likely to be sustained in the future and contribute to the viability of the whole health system. This article proposes a conceptual framework to monitor the performance of externally‐assisted health projects in building their own sustainability. Possible criteria and indicators are discussed.
Assessing prescribing practice: A tanzanian example
Authors: Gilson Lucy , Jaffar Shabbar , Mwankusye Samuel , Teuscher Thomas
Published: May 2007

This article presents the results of an assessment of prescribing practice, undertaken in the Morogoro region of Tanzania. As part of a wider evaluation of performance in primary level health units, retrospective data from patient registers and prospective data from observations of consultation practice were assessed using indicators proposed by the International Network of Rational Use of Drugs. Tanzanian prescribing practices compared favourably with other countries where studies using the same indicators have been undertaken. However, relatively high proportions of incorrect prescriptions were identified, with particular problems of under‐prescribing. Church units were also found to perform less well than government units against the indicators used; differences between the dispensary and health centre level were few. Actions to address the problems highlighted by this study include more careful monitoring and regulation of non‐government health care and identification of the root causes of under‐prescribing in government units. Review of prescribing practice using appropriate indicators is important in both cases, although also requiring wider regulatory action, health provider and patient education, and action to tackle the low morale of health workers.
Health insurance and private providers: A study of the civil servants' medical benefit scheme in bangkok, Thailand
Authors: Bennett Sara , Tangcharoensathien Viroj
Published: May 2007

Compulsory health insurance schemes have received attention recently as a means of creating a reliable extra‐budgetary source of health care funding. Yet, the full implications of such schemes in a developing country context are unclear; in particular, the impact on and relationship with private sector providers has infrequently been explored. This study examines patterns of public and private sector utilization under the Civil Servants' Medical Benefit Scheme (CSMBS) in Bangkok, Thailand. The CSMBS currently provides limited reimbursement for private inpatient care, but recent proposals suggest increasing benefit levels for care sought in the private sector. The study shows that despite high level of cost recovery in the public sector, charges were much lower than those in the private sector. Different patterns of diagnosis in the two sectors were found with private hospitals tending to treat a less complex case mix. Within the private sector, there was a limited tendency to specialize in certain types of care. It is concluded that under the current payment mechanism of fee‐for‐service reimbursement, measures to enhance access to private sector care should be approached with caution. In the long run, the scheme should merge with the recently established social security scheme.
Health system reform in former socialist countries of europe
Authors: Ensor Tim
Published: May 2007

The health systems of all the former socialist countries of Europe are in the midst of far‐reaching reform. The process is still in the early stages but certain patterns of finance and provision are beginning to emerge in a number of countries. All are implementing payroll‐based social insurance while some are beginning to restrict entitlement to those contributing. There is a danger the process of restructuring will leave many without adequate insurance cover. Market solutions are being introduced in many countries to improve the efficiency of provision. Assuming the administrative cost is not too great, this may improve choice and quality of personal care. It is, however, unclear how far these solutions will tackle the fundamental public health problems endemic in these countries today. Those countries that have been slower to implement reform may benefit from learning from the successes and failures of the pioneers.
Rapid assessment of an african district health system. Test of a planning tool
Authors: Nordberg Erik , Oganga Hezron , Kazibwe Sam , Onyango Jared
Published: May 2007

Occasional rapid health care system assessments are potentially useful for planning, for monitoring health care systems development over time, and for comparing health systems in different areas. With the decentralization of health sector management, for example in Kenya, there is a growing need of such assessments at district and sub‐district levels. Can rapid assessments be conducted at affordable cost at these levels? What variables and methods are feasible?

This paper reports on a rapid health system assessment conducted in rural Kenya during 1991. It required the completion at each health facility of a self‐administered questionnaire which included questions on resources, health care programmes, management, service output, and prominent problems. It also included interviews with officers in charge of each health institution in the sub‐district and an examination of records and reports available at each facility

The paper presents the range of issues addressed, the indicators used, the methods applied, the problems encountered, the costs of the assessment, and a small selection of the findings. We conclude that the assessment model is manageable at district level with modest planning and analysis support from central level. Field staff need more precise instructions for completion of the questionnaire, and more population‐based estimates need to be calculated. Reassessment taking place every 3–5 years should be adequate for monitoring the process of change in the local health care system.
Quality assurance management methods applied to a local‐level primary health care system in rural Nigeria
Authors: Zeitz Paul S. , Salami Charles G. , Burnham Gilbert , Goings Stella A. J. , Tijani Kyari , Morrow Richard H.
Published: May 2007

Management of primary health care (PHC) systems in less developed countries is often impeded by factors such as poorly trained personnel, limited financial resources, and poor worker morale. This study explored the ability of local‐level PHC supervisors in rural Nigeria to use quality assurance (QA) management methods to improve the quality of the PHC system

PHC supervisors from Bama Local Government Area were trained for 3 days in the use of QA methods and tools. The supervisors targeted the supervisory system and the health information system (HIS) for improvement. Health worker performance in diarrhoea case management was assessed, using a simulated case, to measure the impact of supervision. A HIS audit assessed data collection forms used by 17 PHC facilities. Gaps in quality were monitored over a 2‐month study period and flaws in work processes were modified

PHC supervisors introduced a checklist during monthly visits to facilities to monitor how workers managed cases of diarrhoea. Performance in history‐taking, physical examination, disease classification, treatment and counselling improved over the evaluation period. The HIS audit found that a variety of reporting forms were used at PHC facilities. After HIS reporting was standardized, the number of health facilities using a daily disease registry significantly improved during the study period

QA management methods were used by PHC supervisors in Nigeria to improve supervision and the HIS. QA management methods are appropriate for improving the quality of the PHC in Nigeria and in other less developed countries where at least a minimal PHC infrastructure exists.
Japanese hospitals—culture and competition: A study of ten hospitals
Authors: Anbäcken Owe
Published: May 2007

Japanese health care is characterized by a pluralistic system with a high degree of private producers. Central government regulates the prices and the financing system. All citizens are covered by a mandatory employment‐based health insurance operating on a nonprofit basis. The consumer has a free choice of physician and hospital. A comparison between Japan, Sweden and some other countries shows significant dissimilarities in the length of stay, number of treatments per hospital bed and year and the staffing of hospitals. About 80 per cent of the hospitals and 94 per cent of the clinics are privately owned. The typical private hospital owned by a physician has less than 100 beds

In this paper, data collected (1992/93) in an empirical study of Japanese hospitals and their leadership is presented. Also discussed are the hospitals' style of management, tools and strategies for competition and competences—personal and formal skills required of the leadership in the hospital

There follows a study of ten hospitals, among which hospital directors and chief physicians were interviewed. Interviews are also made with key persons in the Ministry of Health and Welfare and other organizations in the health care field. The result is also analysed from a cultural perspective—‘what kind of impact does the Japanese culture have on the health care organization?’ and/or ‘what kind of sub‐culture is developed in the Japanese hospitals’. Some comparisons are made with Sweden, USA, Canada and Germany. The different roles of the professions in the hospital are included in the study as well as the incentives for different kinds of strategies — specialization, growing in size, investments in new equipment, different kind of ownership and hospitals. Another issue discussed is the attempt to uncover whether there is an implicit distribution of specialities—silent agreements between hospitals, etc.
The management of health services in Tanzania: A plea for health sector reform
Authors: Sandiford Peter , Kanga George J. , Ahmed Abdullahi M.
Published: May 2007

There are essentially four main approaches used in attempts to strengthen the management of health services in developing countries. These are: information system development; management training; use of planning and evaluation methodologies; and, health sector reform. As part of a collaborative research project based in Kisarawe District, Tanzania, we tested the hypothesis that a combination of the first three of these approaches would be sufficient to ensure that decisions and actions were taken to bring about major improvements in the management of health services. It was assumed that the decentralization, which took place as part of the 1982 reorganization of local government responsibilities, had provided managers with sufficient decision‐making autonomy to allow them to bring about improvement in health service performance, provided that the other conditions were met

In fact, it was found that despite being presented with clear evidence of serious inefficiencies and inequities in the allocation of health resources, managers were often highly reluctant to decide upon actions which would alleviate the problems in situations where there were potential losers as well as winners, even if the benefits greatly outweighed the costs

This article argues that interventions based solely on training, information systems, or planning and evaluation protocols will make only marginal improvements to health service management, and that changes to the system as a whole are needed in order to provide managers and health professionals with incentives to rectify performance failings. Some ideas for health sector reform, to give managers power and incentives for improving efficiency and quality of care, are put forward. Since it is likely that the systemic problems of the health sector in Tanzania are shared by many other developing countries, the lessons drawn from this study probably have more general applicability.
Voices from the inside: Managing district health services in Nepal
Authors: Aitken Jean‐Marion
Published: May 2007

Apparent inconsistencies and irrational decisions can be found in all organizations and they often point to underlying attitudes and assumptions among staff, about the organization and the way it works. Concepts such as ‘negotiated order’ and ‘values in use’ have been suggested in recent literature on organization theory to describe the important role of individual, and social, needs and expectations upon the functioning of organizations. This article presents the apparently common assumptions made about government service, as encountered during research into the management of district public health services in Nepal. It argues that, when taken together, these form a wide and coherent system of ‘values in use’, or an ‘implicit theory’ which appears to guide many of the bureaucracy's actions

The way in which staff are selected and promoted, common attitudes towards work, the shortcomings of the reporting systems, all appear to be part of an ‘implicit’ theory which is based on the fundamental belief that it is the main purpose of the district public health service to provide incomes for its staff. Thus, most posts do not have job descriptions and staff are recruited to them on the basis of factors other than the skills or knowledge required. Training and supervision are seen commonly as means of earning extra allowances, and service quality is not seen as a priority. This contrasts with the ‘official’ theory which is that the organization exists to provide health services to the community and that it is the purpose of the staff to provide those services

Such an implicit ‘theory’, recognized and accepted by staff but never acknowledged, and based on very different values and expectations to those assumed in a ‘rational’, task‐oriented bureaucracy, obviously has implications for the success of development programmes. It explains why training so rarely results in improved performance and why the bureaucracy is so resistant to change which does not satisfy the implicit theory. While the implicit theory described here is specific to Nepal, the phenomenon may be widespread. The failure to take account of such ‘theories in use’, guiding the actions of staff and hence organizations, could explain the failure of many attempts to improve government health services.
Implementing health management information systems: Measuring success in Korea's health centers
Authors: Chae Young Moon , Kim Suk Il , Lee Byung Hwa , Choi Sung Hae , Kim In Sook
Published: May 2007

This article analyses the effects that the introduction and adoption of a health management information system (HMIS) can have on both the productivity of health center staff as well as on user‐satisfaction. The focus is upon the service provided by the Kwonsun Health Center located in Suwon City, Korea. Two surveys were conducted to measure the changes in productivity and adoption (knowledge, persuasion, decision, implementation and confirmation) of health center staff over time. In addition, a third survey was conducted to measure the effects of HMIS on the level of satisfaction perceived by the visitors, by comparing the satisfaction level between the study health center and a similar health center identified as a control. The results suggest that HMIS increased the productivity and satisfaction of the staff but did not increase their persuasion and decision levels; and, that it also succeeded in increasing the levels of visitors' satisfaction with the services provided.
An overview of hospital accreditation in Taiwan, Republic of China
Authors: Huang Ping
Published: May 2007

This paper examines the hospital accreditation system in Taiwan, Republic of China. The paper describes the historical evolution of accreditation; preliminary teaching hospital accreditation; hospital and teaching hospital accreditation; issues and problems; and perspectives and challenges.
Friction and wear behavior of poly(vinyl alcohol)/poly(vinyl pyrrolidone) hydrogels for articular cartilage replacement
Authors: Katta Jayanth K. , Marcolongo Michele , Lowman Anthony , Mansmann Kevin A.
Published: May 2007

Many hydrogels have been proposed as articular cartilage replacements as an alternative to partial or total joint replacements. In the current study, poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) hydrogels were investigated as potential cartilage replacements by investigating their in vitro wear and friction characteristics in a pin‐on‐disk setup. A three‐factor variable‐level experiment was designed to study the wear and friction characteristics of PVA/PVP hydrogels. The three different factors studied were (a) polymer content of PVA/PVP hydrogels, (b) load, and (c) effect of lubricant. Twelve tests were conducted, with each lasting 100,000 cycles against Co–Cr pins. The average coefficient of friction for synovial fluid lubrication was a low 0.035 compared with 0.1 for bovine serum lubrication. Frictional behavior of PVA/PVP hydrogels did not follow Amonton's law of friction. Wear of the hydrogels was quantified by measuring their dry masses before and after the tests. Higher polymer content significantly reduced the wear of hydrogel samples with 15% PVA/PVP samples, showing an average dry polymer loss of 4.74% compared with 6.05% for 10% PVA/PVP samples. A trend change was observed in both the friction and wear characteristics of PVA/PVP hydrogels at 125 N load, suggesting a transition in the lubricating mechanism at the pin‐hydrogel interface at the critical 125 N load. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Chiral separation of dansyl amino acids in capillary electrophoresis using mono‐(3‐methyl‐imidazolium)‐β‐cyclodextrin chloride as selector
Authors: Tang Weihua , Ong Teng Teng , Ng Siu‐Choon
Published: May 2007

Enantioseparations of fourteen dansyl amino acids were achieved by using a positively‐charged single‐isomer β‐cyclodextrin, mono‐(3‐methyl‐imidazolium)‐β‐cyclodextrin chloride, as a chiral selector. Separation parameters such as buffer pH, selector concentration, separation temperature, and organic modifier were investigated for the enantioseparation in order to achieve the maximum possible resolution. Chiral separation of dansyl amino acids was found to be highly dependent on pH since the degree of protonation of these amino acids can alter the strength of electrostatic interaction and/or inclusion complexation between each enantiomer and chiral selector. In general, the chiral resolution of dansyl amino acids was enhanced at higher pH, which indicates that the carboxylate group on the analytes may interact with the imidazolium group of cationic cyclodextrin. For most analytes, a distinct maximum in enantioresolution was obtained at pH 8.0. Moreover, the chiral separation can be further improved by careful tuning of the separation parameters such as higher selector concentration (e. g. 10 mM), lower temperature, and addition of methanol. Enantioseparation of a standard mixture of these dansyl amino acids was further achieved in a single run within 30 min.
Separation of fifteen quinolones by high performance liquid chromatography: Application to pharmaceuticals and ofloxacin determination in urine
Authors: Cañada‐Cañada Florentina , Espinosa‐Mansilla Anunciación , Muñoz de la Peña Arsenio
Published: May 2007

A simple chromatographic method is described for assaying 15 quinolones and fluoroquinolones (pipemidic acid, marbofloxacin, enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid, flumequine and piromidic acid), in urine and pharmaceutical samples. The determination was achieved by LC using an RP C18 analytical column. A mobile phase composed of mixtures of methanol–ACN–10 mM citrate buffer at pH 3.5 and 10 mM citrate buffer at pH 4.5, delivered under an optimum gradient program, at a flow rate of 1.5 mL/min, allows to accomplish the chromatographic separation in 26 min. For detection, diode‐array UV–Vis at 280 nm and fluorescence detection set at excitation wavelength/emission wavelength: 280/450, 280/495, 280/405 and 320/360 nm were used. Detection and quantification limits were between 0.3–18 and 0.8–61 ng/mL, respectively. The method was validated in terms of interday (n = 6) and intraday (n = 6) precision and accuracy. The procedure was successfully applied to the analysis of human and veterinary pharmaceuticals. Also, ofloxacin was determined in human urine samples belonging to a patient undergoing treatment with this active principle, among others.
Molecular processes and structural alterations in laser reshaping of cartilage
Authors: Ignatieva N , Zakharkina O , Leroy G , Sobol E , Vorobieva N , Mordon S
Published: May 2007

The effects of non-destructive laser irradiation on the structure and molecular processes in cartilage were studied using Raman microscopy, differential scanning calorimetry and biochemical analysis. A structural reorganization of the irradiated tissue similar to poliginization in polycrystalline solids was observed for the first time in a cartilage matrix. The difference in the Raman spectra of the irradiated and control samples was interpreted in term of a conformational alteration of glycosaminoglycan macromolecules in the reshaping mode. Laser induced modification of collagen macromolecules was not revealed by Raman spectroscopy. Thermal and biochemical analysis confirmed a preservation of triple helix for laser settings used for laser-induced stress relaxation and reshaping of cartilage.
Characterization of Superfine Wool Powder/Poly(propylene) Blend Film
Authors: Xu Weilin , Wang Xin , Li Wenbin , Peng Xuqiang , Liu Xin , Wang Xun Gai
Published: May 2007

Superfine wool powder was blended and extruded with poly(propylene) (PP) to produce blend pellets, and the extruded pellets were hot‐pressed into a blend film. SEM photographs show that the powder could be uniformly incorporated with PP after extrusion. FT‐IR spectra shows that no substantial changes occurred in the chemical structure of both PP and wool powder in the blend film. X‐Ray diffraction analysis indicates that crystallinity of the blend film was much higher than that of the wool powder and little lower than that of PP. TG‐tested results indicate that the thermal stability of the blend film declined with an increase in the powder content. Endothermic peaks of the wool powder in the blend film become more obvious as the powder content increases. Mechanical properties decline greatly with an increase in the wool powder content in the blend film.

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Some Results Concerning a Class of Differential Equations with Piecewise Constant Argument
Authors: Papaschinopoulos Garyfalos
Published: May 2007

Under some conditions the asymptotic behavior of the solutions of a class of differential equations with piecewise constant argument is studied.
Heat Equation Asymptotics of Elliptic Operators with Non‐scalar Leading Symbol
Authors: Branson Thomas P. , Gilkey Peter B. , Pierzchalski Antoni
Published: May 2007

Let M be a compact smoot Riemannian manifold without boundary and let D = ad0δ0 + bδ1d1 – E on the space of smooth sections of the cotangent bundle where a and b are positive constants and where E is an endomorphism. We use functorial methods and the pseudo‐differential operator calculus to compute the quadratic term a4(D) in the asymptotic expansion of the heat equation trace.
The Riemann Hypothesis for Polynomials Orthogonal on the Unit Circle
Authors: Hamilton Xian‐Jin Li Of
Published: May 2007

An axiomatic treatment is first given of certain Hilbert spaces of polynomials which are implicit in the Szegö theory of polynomials orthogonal on the unit circle [7]. Methods of factorization theory are applied to determine the isometric inclusion of such spaces. Every Szegö space is determined by a polynomial which has no zeros in the unit disk and by an integer r which is greater than or equal to the degree of the polynomial. A positivity condition is formulated for a Szegö space in terms of a quantum q, which is a given number with 0 < q < 1. The quantum can be used to state a functional identity for the defining polynomial. The quantum positivity condition implies that the zeros of the defining polynomial lie on a circle determined by the functional identity. Even when no functional identity is satisfied, the quantum positivity condition denies the existence of twin zeros which are symmetrically placed about the circle. The quantum positivity condition is also applied to weighted Hardy spaces. A characterization is given of those weight functions for which the associated space satisfies the quantum positivity condition. A theorem on the asymptotic behavior of derived Szegö spaces is obtained under a quantum positivity hypothesis for weighted Hardy space. These results are used in an interpretation of the convergence of the Euler product for the zeta‐function of a function field with finite constants field.
A Note on Almost Regular Graphs
Authors: Hofmeister Munich M. Of
Published: May 2007

It can easily be seen that a conjecture of Runge does not hold for a class of graphs whose members will be called “almost regular”. This conjecture is replaced by a weaker one, and a classification of almost regular graphs is given.
A Regularity Result of Nikolskii Type for an Evolution Equation on Compact Homogeneous Spaces
Authors: Bondioli Christiana
Published: May 2007

In the previous paper [2], we proposed a definition of a class of function spaces of Nikolskii type on a special class of riemannian manifolds, namely the manifolds M admitting a transitive compact connected Lie group of isometries. In this paper we continue the subject and we complete the proof that the spaces we have introduced coincide with the classical ones, defined through (finitely many) local charts of M. Moreover, our equivalent definition of these spaces allows us to prove here a regularity result for the solution of a Stefan‐like problem on M, in which the initial datum is assumed to be of Nikolskii type.
Delta‐waves for Semilinear Hyperbolic Cauchy Problems
Authors: Oberguggenberger Michael , Wang Ya‐Guang
Published: May 2007

This paper deals with the propagation of strong singularities for constant coefficient semilinear hyperbolic equations and systems. Limits of regularized solutions are computed as the initial data converge to derivatives of Dirac measures on lower dimensional submanifolds. A general method is given which applies whenever the fundamental solution to the principal part is an integrable measure. Particular cases are semilinear first order systems in one space variable and the semilinear Klein‐Gordon equation in at most three space variables.
On the Pathwise Comparison of Jump Processes Driven by Stochastic Intensities
Authors: Brandt A. , Last G.
Published: May 2007

In this paper we present a pathwise comparison theorem for jump processes governed by stochastic intensities and taking values in an arbitrary partially ordered Polish space. This generalizes recent results for the real‐valued case. The proof given here is based on competing risk arguments rather than on thinning and allows to avoid additional domination conditions. For real valued processes we obtain an almost sure pathwise representation of the comparison result based on an i.i.d. sequence of (0, 1)‐uniformly distributed random variables. For Markov chains our conditions coincide with the classical comparison conditions.
A Quadrature Method for the Singular Integral Equation on Curves with Corner Points
Authors: Buehring Kathrin
Published: May 2007

This paper is concerned with a quadrature method for the approximate solution of the singular integral equation magnified image on the closed curve Γ with a finite number of corner points. Here 𝒶 and 𝒷 are piecewise continuous functions on Γ. We establish necessary and sufficient conditions for the stability of the quadrature method and, in addition, derive the convergence rates. For this we shall apply techniques similar to those used in the case where Γ is an interval (cf. [8]). The crucial point is a change of the variables depending on a parameter and a subsequent application of a simple quadrature rule on a uniform grid.
Rapidly Decreasing Solutions of the KdV Hierarchy
Authors: Feng Xueshang
Published: May 2007

In this paper, by considering the Cauchy Problem for the KdV hierarchy in certain weighted Sobolev spaces, the existence of rapidly decreasing solutions is established.
On Vector‐valued Inequalities of the Marcinkiewicz‐Zygmund, Herz and Krivine Type
Authors: Gasch J. , Maligranda L.
Published: May 2007

Any continuous linear operator T: Lp → Lq has a natural vector‐valued extension T: Lp(l) → Lq(l) which is automatically continuous. Relations between the norms of these operators in the cases of p = q and r = 2 were considered by Marcinkiewicz‐Zygmund [28], Herz [14] and Krivine [19] ‐ [21]. In this paper we study systematically these relations and given some applications. It turns out that some known results can be proved in a simple way as a consequence of these developments.
Entropy Numbers in Weighted Function Spaces and Eigenvalue Distributions of Some Degenerate Pseudodifferential Operators I
Authors: Haroske Dorothee , Triebel Hans
Published: May 2007

In this paper we study weighted function spaces of type B(ℝn, Q(x)) and F(ℝn, Q(x)), where Q(x) is a weight function of at most polynomial growth. Of special interest are the weight functions Q(x) = (1 + |x|2)α/2 with α ϵ ℝ. The main result deals with estimates for the entropy numbers of compact embeddings between spaces of this type.
Asymptotic Properties of N‐th Order Differential Equations with Delayed Argument
Authors: Džurina Jozef
Published: May 2007

The aim of this paper is to deduce oscillatory and asymptotic behaviour of delay differential equationLnu(t)– P(t)u(τ(t))= 0 from the oscillation of a set of the first order delay differential equations with larger deviating argument of the formy′(t)+ qi(t) y(w(t)) = 0.
Inclusions and Identities for the Moore‐Penrose Inverse of a Closed Linear Operator
Authors: Groetsch C. W.
Published: May 2007

A number of operator inclusions, and identities, involving the Moore‐Penrose inverse of a closed densely defined linear operator, are presented. Some of these inclusions generalize known identities in the case when the operator is bounded and has closed range. An application to a known compactness criterion for the Moore‐Penrose inverse is also given.
A Noncharacteristic Cauchy Problem for Linear Parabolic Equations I: Solvability
Authors: Haò Dinh Nho
Published: May 2007

Noncharacteristic Cauchy problems for parabolic equations arc frequently encountered in many areas of heat transfer. These problems are well known to be severely ill‐posed. In this paper a solvability criterion for a class of such problems is established. It is proved that a weak solution of a noncharacteristic Cauchy problem for linear parabolic equations in divergence form with coefficients in a Holmgren class 2 in time exists if and only if the Cauchy data arc functions of a Holmgren class 2! A function g(t) defined on (α, β) is said to be of a Holmgren class 2, if g ϵC∞ (α, β) and for all nonnegative integers n there exist positive constants c and s such that |g(n)| < csn(2n)!.
Eigenvalue Inequalities and Schubert Calculus
Authors: Helmke Uwe , Rosenthal Joachim
Published: May 2007

Using techniques from algebraic topology we derive linear inequalities which relate the spectrum of a set of Hermitian matrices A1,…, Ar ϵ ¢n×n with the spectrum of the sum A1 + … + Ar. These extend eigenvalue inequalities due to Freede‐Thompson and Horn for sums of eigenvalues of two Hermitian matrices.
Complex Interpolation of Hardy‐Type Subspaces
Authors: Kalton N. J.
Published: May 2007

We consider the problem of complex interpolation of certain Hardy‐type subspaces of Köthe function spaces. For example, suppose that X0 and X1 arc Köthe function spaces on the unit circle T. and let HX0 and HX1 be the corresponding Hardy spaces. Under mild conditions on X0. X1 we give a necessary and sufficient condition for the complex interpolation space [HX0. HX1]0 to coincide with HX0 where HX0 = [H0. H1]0. We develop a very general framework for such results and our methods apply to many more general situations including the vector–valued case.
Real Interpolation for Families of Banach Spaces and Convexity
Authors: Kutzarova D. N. , Nikolova L. Y. , Zachariades T.
Published: May 2007

We show how the geometrical properties of uniform convexity and uniformly non‐𝓁 are inherited by real interpolation spaces for infinite families.
Sommerfeld Half‐plane Problems with Higher Order Boundary Conditions
Authors: Santos P. A. , Teixeira F. S.
Published: May 2007

Sommerfeld‐type diffraction problems for a half‐plane with arbitrary n‐th order generalized impedance boundary conditions arc examined in a Sobolev space setting. The corresponding boundary‐transmission problems for the two dimensional Helmholtz equation are shown to be well‐posed in a family of Sobolev spaces with finite energy norms, through a reduction to equivalent systems of boundary integral equations of Wiener‐Hopf type in [L2+ (IR)]2. Formulas for the solutions as well as the so‐called edge conditions arc obtained for any n, by explicit canonical generalized factorization of the presymbols of the associated Wiener‐Hopf operators.
On a Nation of Resurgent Function of Several Variables
Authors: Sternin Boris , Shatalov Victor
Published: May 2007

The Paper presents the definition of a resurgent a resurgent function of several independent variables. The main properties of the introduced notions are investigated.
On the Two‐step Newton Method for the Solution of Nonlinear Operator Equations
Authors: Appell J. , De Pascale E. , Evkhuta N. A. , Zabrejko P. P.
Published: May 2007

Building on the method of Kantorovich majorants, we give convergence results and error estimates for the two‐step Newton method for the approximate solution of a nonlinear operator equation.
Fourier Transformation of Hilbert C*‐systems, with Compact Groups, by their Regular Representation
Authors: Baumgärtel H.
Published: May 2007

Using Fourier transformation, the generating elements of Hilbert C*‐systems are calculated. Their matrix elements coincide essentially with the coefficients of their multiplication schema.
The Nonclassical Boundary‐contact Problems of Elasticity for Homogeneous Anisotropic Media
Authors: Chkadua O. O.
Published: May 2007

The existence and uniqueness of solutions of the nonclassical boundary‐contact problems (i.e., problems with a contact on some part of the boundaries) of elasticity for homogeneous anisotropic media are investigated in Besov and Bessel potential spaces using methods of potential theory and the theory of pseudodifferential equations on manifolds with boundary. The smoothness of the solutions obtained is studied.
On the Floquet Exponents of Hill's Equation Systems
Authors: Denk Robert
Published: May 2007

For the k × k‐matrix‐valued version of Hill's equation it is shown that the dimension of the matrix needed to compute the Floquet exponents can be reduced from 2k to k. Also the existence of periodic solutions is equivalent to the non‐invertibility of certain k × k‐matrices.
Invariant Inner Ideals in W*‐algebras
Authors: Edwards C. M. , Rüttimann G. T. , Yu. Vasilovsky S.
Published: May 2007

Let H(B,α) be the JBW*‐algebra of elements of a continuous W*‐algebra B invariant under the *‐anti‐automorphism α of B of order two. Then the mapping I → I ∩ H(B, α) is an order isomorphism from the complete lattice of α‐invariant weak* closed inner ideals in B onto the complete lattice of weak* closed inner ideals in H(B, α), every one of which is of the form eH(B, α) α(e) for some unique projection e in B with α‐invariant central support. A corollary of this result completely characterizes the weak* closed inner ideals in any continuous JBW*‐triple.
Weighted Inequalities for Monotone Functions
Authors: García Alejandro
Published: May 2007

Weighted norm inequalities are investigated by giving an extension of the Riesz convexity theorem to semi‐linear operators on monotone functions. Several properties of the classes B(p, n) and C(p, n) introduced by Neugebauer in [13] are given. In particular, we characterize the weight pairs w, v for which \documentclass{article}\pagestyle{empty}\begin{document}$ \int\limits_0^\infty {f(x)^p w(x)dx \le C \int\limits_0^\infty {({\textstyle{1 \over x}}\int\limits_0^x f)^p } v(x) dx,} $\end{document} for nondecreasing functions f and 1 ≦ p < ∞.
Long‐Time Behaviour of Langevin Algorithms with Time‐dependent Energy Function
Authors: Grillo Gabriele
Published: May 2007

We study the Langevin algorithm on C∞ n‐dimensional compact connected Riemannian manifolds and on IRn, allowing the energy function U to vary with time. We find conditions under which the distribution of the process at hand becomes indistinguishable as t → ∞ from the “instantaneous” equilibrium distribution. Such conditions do not necessarily imply that U(t) converges pointwise as t → ∞.
Hypersurfaces in E4 with Harmonic Mean Curvature Vector Field
Authors: Hasanis Th. , Vlachos Th.
Published: May 2007

The minimal hypersurfaces in E4 are the only hypersurfaces possessing the following property: Its mean curvature vector field is harmonic.
O*‐algebras in Standard System
Authors: Inoue Atsushi
Published: May 2007

In the previous papers [10, 12] we have defined and studied the notion of standard generalized vectors which makes possible to develop the Tomita‐Takesaki theory in algebras of unbounded operators called O*‐algebras. The main purpose of this paper is to consider when an O*‐algebra is algebraically or spatially isomorphic to an O*‐algebra with a standard generalized vector.
Determining the Monogeneity of a Quartic Number Field
Authors: Koppenhöfer David
Published: May 2007

This note presents a method that determines all power integral bases of a quartic number field by solving Thue equations of degrees 3 and 4. To this end, projective representations of the ring of integers by graded complete intersections are studied and a criterion for monogeneity in terms of projective representations is derived.
Fredholm Theory for a Class of Singular Integral Operators with Carleman Shift and Unbounded Coefficients
Authors: Kravchenko V. G. , Lebre A. B. , Litvinchuk G. S. , Teixeira F. S.
Published: May 2007

A criterion for the Fredholmness of singular integral operators with Carleman shift in LP(Γ) is obtained, where Γ is either the unit circle or the real line. The approach allows to consider unbounded coefficients in a class related to that of quasicontinuous functions. Applications to Wiener‐Hopf‐Hankel type operators and operators with linear fractional Carleman shift on IR are included.
Differentiation of the Martinelli‐Bochner Integrals and the Notion of Hyperderivability
Authors: Mitelman Igor M. , Shapiro Michael V.
Published: May 2007

The notion of hyperderivability is introduced and discussed which allows us to obtain, in particular, formulas for the derivatives of the Martinelli‐Bochner integrals.
Maximal Probability Inequalities for Stochastic Processes
Authors: Móricz F.
Published: May 2007

Let Xa,b be nonnegative random variables with the property that Xa,b ≦ Xa,c + Xc.b for all 0≦ a < c < b ≦ T, where T > 0 is fixed. We define Ma,b = sup {Xa,c: a < c ≦ h} and establish bounds for P[Ma,b ≧ λ] in terms of given bounds for P[Xa,b ≧ λ], where λ runs through some interval (0, λo), 0 < λo ≦ ∞ fixed. These bounds explicitly involve a nonnegative function g(a, b) assumed to be quasi‐superadditive with an index Q, i.e., g(a, c) + g(c, b) ≦ Qg(a, b) for all 0≦ a < c < b < T, where 1 ≦ Q < 2 is fixed.

Maximal inequalities obtained in this way can be applied to stochastic processes exhibiting long‐range dependence. Among others, these applications may include certain self‐similar processes such as fractional Brownian motion, stochastic processes occurring in linear time series models, etc.
Weighted Norm Inequalities for General Maximal Operators and Approach Regions
Authors: Sánchez‐Colomer Ascensión , Soria Javier
Published: May 2007

We find a characterization of a two‐weight norm inequality for a maximal operator and we obtain, as a consequence, strong type estimates for the maximal function over general approach regions.
Asymptotic Analysis of the Lyapunov Exponents of Certain Linear Hamiltonian Systems with Small Noise
Authors: Teichert Heidrun
Published: May 2007

In the paper there are considered linear Hamiltonian systems in R2n which include a small additive random term depending on a stationary ergodic Markov process. Under some regularity assumptions we derive asymptotic expansions for certain Lyapunov exponents of the systems (or for sums of them). The method used here is also applicable to the asymptotic analysis of a generalized rotation number.
Square Powers of Singularly Perturbed Operators
Authors: Albeverio Sergio , Karwowski Witold , Koshmanenko Vladimir
Published: May 2007

We use the method of self‐adjoint extensions to define a self‐adjoint operator AT as the singular perturbation of a given self‐adjoint operator A by a singular operator T on a Hilbert space.

We also find the structure of a singular operator Q such that the singular perturbation of A2 by Q satisfies (A2)Q = (AT)2. We obtain the explicit form of Q in terms of A and T. A definition of the n‐th power for strictly positive symmetric operators is also given.
Bögel Functions, Tensor Products and Blending Approximation
Authors: Badea C. , Cottin C. , Gonska H. H.
Published: May 2007

For two compact metric spaces X and Y, we prove that the space of all bounded Bögel functions on X × Y is isometrically isomorphic with the completion of the blending function space M(X) ⊗ C(Y)+ C(X) ⊗ M(Y) with respect to a suitable norm. This solves a problem raised by G. Freud. Here M(Z) and C(Z) denote the spaces of all bounded and continuous functions on the metric space Z, respectively. Applications are given to some problems in so‐called blending approximation. All this is based on an abstract Jackson‐type theorem in terms of the entropy numbers of X and Y and the mixed modulus of smoothness.
Finite Interval Convolution Operators on the Bessel Potential Spaces H
Authors: Bastos M. A. , Dos Santos A. F. , Duduchava R.
Published: May 2007

Finite interval convolution operators acting between Bessel potential spaces Hsp are studied in regard to Fredholm properties and invertibility. The Fourier transform of the kernel‐function of the operator is assumed to be piecewise continuous on R. An example from diffraction theory is included.
Method of Discrepancy in Interpolation Spaces for Nonlinear Ill‐posed Problems
Authors: Buong Nguyen
Published: May 2007

In this note we study a variational method of regularization to solve nonlinear ill‐posed problems involving monotone operators in infinite dimensional Banach space, when perturbative operators are non ‐ monotone, basing on minimization of norm in interpolation space over closed and convex sets.