bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory Experiments on Eddy Generation by a Buoyant Coastal Current Flowing over Variable Bathymetry*
Authors: Wolfe Christopher L. , Cenedese Claudia
Published: April 2006

Irminger rings are warm-core eddies formed off the west coast of Greenland. Recent studies suggest that these eddies, which are implicated in the rapid springtime restratification of the Labrador Sea, are formed by an internal instability of the West Greenland Current (WGC), triggered by bathymetric variations. This study seeks to explore the effect of the magnitude and downstream length scale of bathymetric variations on the stability of a simple model of the WGC in a series of laboratory experiments in which a buoyant coastal current was allowed to flow over bathymetry consisting of piecewise constant slopes of varying magnitude. The currents did not form eddies over gently sloping bathymetry and only formed eddies over steep bathymetry if the current width exceeded the width of the sloping bathymetry. Eddying currents were immediately stabilized if they flowed onto gently sloping topography. Bathymetric variations that persisted only a short distance downstream perturbed the flow locally but did not lead to eddy formation. Eddies formed only once the downstream length of the bathymetric variations exceeded a critical scale of about 8 Rossby radii. These results are consistent with the observed behavior of the WGC, which begins to form Irminger rings after entering a region where the continental slope abruptly steepens and becomes narrower than the WGC itself in a region spanning about 20–80 Rossby radii of downstream distance.
Spectral Distribution of Energy Dissipation of Wind-Generated Waves due to Dominant Wave Breaking
Authors: Young Ian R. , Babanin Alexander V.
Published: April 2006

This paper considers an experimental attempt to estimate the spectral distribution of the dissipation due to breaking of dominant waves. A field wave record with an approximately 50% dominant-breaking rate was analyzed. Segments of the record, comprising sequences of breaking waves, were used to obtain the “breaking spectrum,” and segments of nonbreaking waves were used to obtain the “nonbreaking spectrum.” The clear visible difference between the two spectra was attributed to the dissipation due to breaking. This assumption was supported by independent measurements of total dissipation of kinetic energy in the water column at the measurement location. It is shown that the dominant breaking causes energy dissipation throughout the entire spectrum at scales smaller than the spectral peak waves. The dissipation rate at each frequency is linear in terms of the wave spectral density at that frequency, with a correction for the directional spectral width. A formulation for the spectral dissipation function able to accommodate this effect is suggested. Directional spectra of the breaking and nonbreaking waves are also considered. It is shown that directional dissipation rates at oblique angles are higher than the dissipation in the main wave propagation direction.
Parametric Representation of the Primary Hurricane Vortex. Part II: A New Family of Sectionally Continuous Profiles
Authors: Willoughby H. E. , Darling R. W. R. , Rahn M. E.
Published: April 2006

For applications such as windstorm underwriting or storm-surge forecasting, hurricane wind profiles are often approximated by continuous functions that are zero at the vortex center, increase to a maximum in the eyewall, and then decrease asymptotically to zero far from the center. Comparisons between the most commonly used functions and aircraft observations reveal systematic errors. Although winds near the peak are too strong, they decrease too rapidly with distance away from the peak. Pressure–wind relations for these profiles typically overestimate maximum winds.

A promising alternative is a family of sectionally continuous profiles in which the wind increases as a power of radius inside the eye and decays exponentially outside the eye after a smooth polynomial transition across the eyewall. Based upon a sample of 493 observed profiles, the mean exponent for the power law is 0.79 and the mean decay length is 243 km. The database actually contains 606 aircraft sorties, but 113 of these failed quality-control screening. Hurricanes stronger than Saffir–Simpson category 2 often require two exponentials to match the observed rapid decrease of wind with radius just outside the eye and slower decrease farther away. Experimentation showed that a fixed value of 25 km was satisfactory for the faster decay length. The mean value of the slower decay length was 295 km. The mean contribution of the faster exponential to the outer profile was 0.10, but for the most intense hurricanes it sometimes exceeded 0.5. The power-law exponent and proportion of the faster decay length increased with maximum wind speed and decreased with latitude, whereas the slower decay length decreased with intensity and increased with latitude, consistent with the qualitative observation that more intense hurricanes in lower latitudes usually have more sharply peaked wind profiles.
Short Changed
Authors: Lucey Thomas A. , Giannangelo Duane M.
Published: April 2006

Through this literature review, the authors explore financial education’s relevance to urban society. They consider research measuring children’s financial development by observing environmental influences that affect both financial learning and personal judgments. These conditions necessitate financial curricula addressing associated challenges. The authors recommend a cooperative rather than competitive financial education curriculum. Such a framework would employ student-centered instruction to create awareness of the societal consequences for financially based personal judgments related to financial differences.
Achievement and Enrollment Status of Suspended Students
Authors: Arcia Emily
Published: April 2006

There have been outcries in both the academic sector and in the popular press about the high and increasingly rising use of suspensions as a discipline measure. Among the negative consequences noted has been a detrimental impact on the academic achievement of suspended students. This article presents the results of longitudinal retrospective analyses on suspensions, achievement, and long-term enrollment status of students in a large, urban school district. The pre- and postsuspension reading achievements of suspended students were compared to those of a comparison group matched on grade, gender, race, participation in the free/reduced lunch program, and limited English proficiency. Findings indicated that suspended students had substantially lower presuspension achievement than did students in the comparison group, gained considerably less academically throughout 3 years with suspensions, and had high drop-out rates. All patterns were considerably more marked with increases in suspensions and with decreases in achievement.
Influence of language-specific input on spatial cognition: Categories of containment
Authors: Choi Soonja
Published: April 2006

This study examines whether language-specific input influences children's nonlinguistic spatial cognition as they acquire their first language. Recent research on infant cognition has shown that preverbal infants can make a distinction between tight-fit and loose-fit containment relations. This distinction is systematically made in Korean ( kkita‘fit tightly’), but not in English ( in). Using a preferential-looking method, this study tested sensitivity to the distinction in English and Korean learners at different ages: English learners were tested at 18, 24, 29 and 36 months, and Korean learners at 29 and 36 months of age. Results showed that while English learners weaken their sensitivity to the distinction by 29 months of age, Korean learners maintain high sensitivity to the distinction throughout the age periods tested. Language surveys of the English learners indicate that weakening of the sensitivity occurs as the children use the relevant spatial terms and increase their vocabulary level.
Quai Branly museum: representing France after empire
Authors: Amato Sarah
Published: April 2006

A major new museum is about to open in the heart of Paris. The favoured project of President Chirac, the core of its collection will be comprised of artefacts from Asia, the Americas, the Pacific region and Africa - all regions in which France once had colonies. It was preceded by a prestigious exhibition in the Louvre of sculptures from these regions. But is this an artistic venture or an ethnographic one? That these questions are still being hotly contested, some six years after the project was officially inaugurated by Chirac and as the Museedu Quai Branly is about to open, speaks to how vital they are to the nation’s understanding of, and relationship to, its colonial past.
Race/class politics: the Liberator/, 1929-1934
Authors: Bergin Cathy
Published: April 2006

During the Depression years of the early 1930s, the American Communist Party attracted significant numbers of black activists, writers and workers to its ranks. The black-led Communist paper the Liberator was both the mouthpiece and rallying point for this movement. The type of race-class politics it forged was groundbreaking at the time, but it has been consistently misunderstood and misconstrued by later historians, often writing from a ‘cold war’ perspective. Here, the development of the Liberator’s politics is closely analysed and placed in a historical context that allows its significance for black radicalism and black struggle to emerge.
‘Speak to the Mother to Understand her Son’: An Hypothesis of Intervention with Drug-Addicted Patients
Authors: Degli Stefani Mario
Published: April 2006

This paper is based on clinical observation in a Drug Addition Unit within a public health service. It describes therapy which focuses on psychotherapeutic intervention with the parents of young, drugaddicted patients, enabling those patients to re-elaborate emotions which would be difficult for them to accept, if they were faced with them directly. In synergy with the treatment of the son and through out-patients' activity, the parents become an integral part of the cure within the group, which is voluntary and with other ‘anxious parents’, allowing the recognition and elaboration of some aspects otherwise difficult to reach. Three clinical examples illustrate this.
Pinnock’s Pneumatology: A pentecostal Appreciation
Authors: Macchia Frank
Published: April 2006

This article responds to Clark Pinnock’s address on the ‘Promise of Pentecostal Ecclesiology’ in the context of appreciation for his long and mutually enriching interaction with Pentecostals. The response proceeds to take up Pinnock’s specific ecclesiological proposals by proposing an even fuller way to relate the Spirit with justification and by offering further thoughts on how to develop a theology of the charismatic structure of the church.
‘Not Like it Used to Be?’: Jesus, Miracles, and Today
Authors: Shelton James
Published: April 2006

Keith Warrington claims that Jesus’ healings should not be taken as a model to be followed today and that the reason for the apostles’ powerful healing ministry was the presence and activity of Jesus, thus leaving the Church to a new healing paradigm found in James 5, which, he asserts, explains the decrease in healing today. Yet it would appear that the Apostles do indeed follow Jesus’ model of healing, and the evidence in Acts appears to militate against Warrington’s thesis. One has to ask if healing in James is so ‘markedly different’ from Jesus’ ministry. There is not a third class or third string team after Jesus, then the Apostles. Jesus and the Holy Spirit are still the agents of healing today as they were then.
Reporting through the lens of the past
Authors: Edy Jill A. , Daradanova Miglena
Published: April 2006

Collective memory, the publicly shared meaning of a common past, can structure both news stories and reporters' search for information within the broader context of journalistic practices. It can also provide reporters with an independent perspective, balancing elite-dominated news frames. Following the space shuttle Columbia's crash, journalists turned repeatedly to the ‘lessons' of the accident that claimed the Challenger shuttle 17 years earlier both in formulating questions at NASA briefings and in reporting Columbia's destruction and the subsequent investigation in print. In many instances, journalists' reliance on these memories is entirely implicit in the finished news stories, making Challenger a ghostly presence that led reporters to focus on NASA's inadequacies rather than on the mechanical causes of Columbia's demise.
Spillovers to foreign market participants: assessing the impact of export strategies on innovative productivity
Authors: Salomon Robert M.
Published: April 2006

Although a substantial body of research has investigated spillovers to FDI, we know very little about whether, and how, firms stand to benefit from spillovers without making such crossborder investments. In this study I investigate this issue by examining the ex-post innovative benefits that accrue to exporting firms. I argue that exporters access diverse knowledge inputs not available in the domestic market.This knowledge spills back to the focal firm and results in increased innovation. I explore how exporters derive such knowledge-based advantages by examining the relationship between export strategies and innovative productivity. Specifically, I contend that firms that export to developed countries will experience increased innovative productivity. Similarly, firms that reach the foreign market directly rather than relying on export brokers should innovate more, as they maintain closer ties with their information conduits.The empirical analysis is conducted using a stratified representative sample of Spanish manufacturing firms from 1990 to 1997. The dependent variable (innovation) is measured using several widely employed proxies including patent counts and innovation counts. I find that export strategies influence innovation in complex ways. I discuss the relevance of these findings for research in international business, strategy, and innovation.
Shaping the shareholder activism agenda: institutional investors and global social issues
Authors: Proffitt W. Trexler , Spicer Andrew
Published: April 2006

We examine the issues and actors that have shaped the agenda of shareholder activism on global social issues over the last 35 years. Our analysis of 2158 US shareholders’ proposals on the topics of international human rights and labor standards reveals that a clear agenda has developed, dominated by religious organizations that have sponsored or co-sponsored 1312 of these proposals. Public pension funds entered the field of global social issue activism after religious organizations had already established the legitimacy of the agenda. We suggest that a social movement perspective on shareholder activism best explains these findings. Religious groups framed the ideas that constitute the global social issues shareholder agenda and mobilized support by reaching out to other types of investors. Public pension funds played a secondary, albeit important, role in agenda creation by championing several of the campaigns initiated by religious innovators.
Allies Against Asthma: A Midstream Comment on Sustainability
Authors: Friedman Amy R. , Wicklund Kimberly
Published: April 2006

The ability of a coalition to sustain its impact in a community over time is a vital element of success. Four sustainability strategies have emerged among Allies Against Asthma coalitions: (a) resource development; (b) institutionalization; (c) system change, including policy change; and (d) capacity building. Although it is too early to determine their ultimate success, a number of important lessons have been learned about the coalitions’ sustainability efforts: (a) sustainability must be considered as a planning principle, (b) data demonstrating success will enhance efforts to sustain worthy efforts, (c) ongoing communication and relationship building are critical elements of sustainability, (d) considering sustainability can help guide membership recruitment efforts, (e) coalitions with previous asthma and/or coalition experience may be better prepared to address sustainability within a short project period, and (f) although difficult to fund, the coalition infrastructure itself is key to successfully sustaining outcomes and activities.
Building Allies Coalitions: Why Formation Matters
Authors: Butterfoss Frances D. , Lachance Laurie L. , Orians Carlyn E.
Published: April 2006

This article describes how formation of the Allies Against Asthma coalitions was influenced by community context, history, leadership, membership, structure, processes, and other factors. Based on member surveys, key informant interviews, and self-assessment tools, results indicate that three coalitions developed from existing coalitions, and four formed in response to funding. The coalitions took an average of 12 months to form and completed 98% of formation tasks. Funding, technical support, and networking among grantees promoted formation. Although cultures, geographies, lead agencies, and years of experience differed, coalitions developed similar structures and processes. Two of three new coalitions took the longest to form, highlighting the need for flexibility and technical assistance when funding new coalitions.
Use of Etomidate as an Induction Agent for Rapid Sequence Intubation in a Pediatric Emergency Department
Authors: Zuckerbraun Noel S. , Pitetti Raymond D. , Herr Sandra M. , Roth Kimberly R. , Gaines Barbara A. , King Christopher
Published: April 2006

Objectives:
Although etomidate is widely used for rapid sequence intubation (RSI), there is no consensus on the optimal induction agent and no prospective pediatric emergency department (ED) study exists. The objective of this study was to assess the effectiveness and safety of etomidate as an induction agent for RSI in the pediatric ED.

Methods:
Data on RSI conditions and complications were collected prospectively on patients undergoing RSI in a tertiary pediatric ED from January 2003 to December 2003. ED hemodynamic data and inpatient data were collected retrospectively via chart review.

Results:
Seventy‐seven of 101 patients requiring intubation underwent RSI with etomidate. The mean (± SD) age was 8.2 (± 6.2) years. All 77 patients were successfully intubated. Intubation condition data were available for 69 of 77 patients (89.6%). Conditions were good in 68 of 69 (99%; 95% confidence interval = 92.2% to 99.9%). The mean (± SD) maximal percent decrease in systolic blood pressure was 10% (± 13.6%). A greater than 20% maximal percent decrease in systolic blood pressure occurred in 12 of 69 patients (17.4%; 95% confidence interval = 9.3% to 28.4%). There was no relationship between seizures after etomidate administration and prior seizure history (p = 0.25). Corticosteroids were given to 29 of 77 patients post‐RSI for varying diagnoses. All eight patients given corticosteroids for shock were in shock at the time of intubation.

Conclusions:
In the pediatric ED setting, etomidate as an induction agent provided successful RSI conditions and resulted in varied hemodynamic changes that were especially favorable in those patients presenting in decompensated shock. Hypotension and seizures were uncommon and occurred in patients with confounding diagnoses. Until the significance of a single dose of etomidate on adrenal dysfunction is further clarified, caution should be used in those patients at risk for adrenal insufficiency.
Cbfa-1 mediates nitric oxide regulation of MMP-13 in osteoblasts
Authors: Zaragoza Carlos , López-Rivera Esther , García-Rama Concepción , Saura Marta , Martínez-Ruíz Antonio , Lizarbe Tania R. , Martín-de-Lara Fernando , Lamas Santiago
Published: April 2006

During bone development, osteoblast differentiation requires remodeling of the extracellular matrix. Although underlying mechanisms have not been elucidated, evidence points to the participation of the nitric oxide (NO) and cyclic guanosine 3′,5′-monophosphate (cGMP) system. Here, we detected increased matrix metalloproteinase (MMP)-13 mRNA, protein and activity, as well as increased inducible NO synthase (iNOS) and NO production during the differentiation of MC3T3-E1 osteoblasts. Transcriptional activity of the MMP-13 promoter was augmented by NO, 8-bromo-cGMP (8-Br-cGMP), and by a dominant-positive form of protein kinase G (PKG1-α). The stimulatory effect on the MMP-13 promoter was partially inhibited by mutation of the osteoblast-specific element 2 (OSE-2) binding site. Core binding factor-1 (Cbfa-1) expression peaked at 7 days of differentiation, and was phosphorylated by PKG in vitro. Cbfa-1 was localized to cell nuclei, and its translocation was inhibited by the iNOS inhibitor 1400W. Immunohistological examination revealed that MMP-13 and Cbfa-1 expression levels are both reduced in 17-day-old embryos of iNOS-deficient mice. Silencing of Cbfa-1 mRNA blocked MMP-13 expression without interfering with endogenous NO production, confirming its role in NO-induced MMP-13 expression by MC3T3-E1 cells. The results described here suggest a mechanism by which NO regulates osteogenesis.
Abnormal sterols in cholesterol-deficiency diseases cause secretory granule malformation and decreased membrane curvature
Authors: Gondré-Lewis Marjorie C. , Petrache Horia I. , Wassif Christopher A. , Harries Daniel , Parsegian Adrian , Porter Forbes D. , Loh Y. Peng
Published: April 2006

Cholesterol is an abundant lipid in eukaryotic membranes, implicated in numerous structural and functional capacities. Here, we have investigated the mechanism by which cholesterol affects secretory granule biogenesis in vivo using Dhcr7-/- and Sc5d-/- mouse models of the human diseases, Smith-Lemli-Opitz syndrome (SLOS) and lathosterolosis. These homozygous-recessive multiple-malformation disorders are characterized by the functional absence of one of the last two enzymes in the cholesterol biosynthetic pathway, resulting in the accumulation of precursors. Cholesterol-deficient mice exhibit a significant decrease in the numbers of secretory granules in the pancreas, pituitary and adrenal glands. Moreover, there was an increase in morphologically aberrant granules in the exocrine pancreas of Dhcr7-/- acinar cells. Regulated secretory pathway function was also severely diminished in these cells, but could be restored with exogenous cholesterol. Sterol precursors incorporated in artificial membranes resulted in decreased bending rigidity and intrinsic curvature compared with cholesterol, thus providing a cholesterol-mediated mechanism for normal granule budding, and an explanation for granule malformation in SLOS and lathosterolosis.
A Note on Feedback Sequential Equilibria in a Lanchester Model with Empirical Application
Authors: Breton Michèle , Jarrar Ramla , Zaccour Georges
Published: April 2006

We study in this paper dynamic equilibrium advertising strategies in a duopoly with asymmetric information structure and sequential play. The advertising model of Lanchester is used in a game where the relevant solution concept is feedback Stackelberg equilibrium, which is subgame perfect. An algorithm is devised for the computation of this equilibrium, and numerical results are reported and discussed. Using a data set from the cola market, we obtain the resulting advertising strategies and provide a comparison with closed-loop and open-loop Nash equilibria.
Selectively Acquiring Customer Information: A New Data Acquisition Problem and an Active Learning-Based Solution
Authors: Zheng Zhiqiang , Padmanabhan Balaji
Published: April 2006

This paper presents a new information acquisition problem motivated by business applications where customer data has to be acquired with a specific modeling objective in mind. In the last two decades, there has been substantial work in two different fields—optimal experimental design and machine learning—that has addressed the issue of acquiring data in a selective manner with a specific objective in mind. We show that the problem presented here is different from the classic model-based data acquisition problems considered thus far in the literature in both fields. Building on work in optimal experimental design and in machine learning, we develop a new active learning technique for the information acquisition problem presented in this paper. We demonstrate that the proposed method performs well based on results from applying this method across 20 Web usage and machine learning data sets.
Joint Production and Pricing Decisions with Setup Costs and Capacity Constraints
Authors: Deng Shiming , Yano Candace A.
Published: April 2006

We consider the problem of setting prices and choosing production quantities for a single product over a finite horizon for a capacity-constrained manufacturer facing price-sensitive demands. There is a fixed cost per production run and a variable cost per unit produced, both of which may vary by period. We characterize properties of the optimal solution, considering cases with constant and time-varying capacity, and with and without speculative motive for holding inventory. We show that, counter to intuition, optimal prices may increase as the capacity increases, even when capacity is constant over the horizon. We also show that increases in capacity do not always exhibit diminishing marginal returns.

Our procedure produces solutions with much higher profits than can be obtained from a sophisticated sequential procedure in which a well-informed and optimum-seeking marketing department makes pricing decisions and the manufacturing department seeks to satisfy the resulting demands at minimum cost. Our results also suggest that firms with seasonal demand and tight capacity constraints should be more aggressive in setting prices to manage their demands than what is typically done in practice. Finally, we discuss how a decision maker can use our procedure as an aid in solving multiproduct versions of the problem.
Dynamic Catalog Mailing Policies
Authors: Simester Duncan I. , Sun Peng , Tsitsiklis John N.
Published: April 2006

Deciding who should receive a mail-order catalog is among the most important decisions that mail-order-catalog firms must address. In practice, the current approach to the problem is invariably myopic: firms send catalogs to customers who they think are most likely to order from that catalog. In doing so, the firms overlook the long-run implications of these decisions. For example, it may be profitable to mail to customers who are unlikely to order immediately if sending the current catalog increases the probability of a future order. We propose a model that allows firms to optimize mailing decisions by addressing the dynamic implications of their decisions. The model is conceptually simple and straightforward to implement. We apply the model to a large sample of historical data provided by a catalog firm and then evaluate its performance in a large-scale field test. The findings offer support for the proposed model but also identify opportunities for further improvement.
Historical colonial literature and New Caledonia, 18531945 or how a settlement colony generates hagiographic writings
Authors: Angleviel Frdric
Published: April 2006

New Caledonia's exploration and settlement produced a wide array of historical essays both within and without the colony. Which vision(s) did these essays provide of the emerging New Caledonian society? Does the dichotomy between conditions of life in New Caledonia and the vision provided
thereof result from the historical approaches adopted or the topics being discussed? While these essays reveal a keen interest for New Caledonia's original inhabitants, they also reflect a quest for colonial legitimacy and justification in their othering of New Caledonia's native populations
as primitive and uncivilized.
J'ai toujours t une personne un peu part: questions Maryse Cond
Authors: Hardwick Louise
Published: April 2006

This interview concentrates upon Maryse Cond's literary works since the mid-1980s. Referring to Le Cur rire et pleurer (1999), Cond explains her approach to writing accounts of childhood. Parallels are uncovered between the novels Traverse de la Mangrove (1989) and La
Belle Crole (1999) and the author speaks of her complex links to her country, as well as discussing her position in relation to other francophone Caribbean authors and their literary theories. In addition, Cond's life in London in the late 1960s is described. The interview also probes
the relationship between author and printed text and reveals Cond's conception of the Prix des Amriques insulaires et de la Guyane, a literary prize she co-created in 1999. Finally, the author's projects for the future are outlined.
Les crivains africains francophones et l'essai: littrature d'ides ou prise de position?
Authors: Mouralis Bernard
Published: April 2006

The first part of this essay analyses the works of African writers between 1900 and 1945 and attempts to establish the extent to which these writings reflect the cultural, pedagogical and political aims and objectives of the French colonizing power. The situation was to change considerably
after the Second World War. The establishment of the Union franaise effectively ended the colonial education system and Africans were allowed access to universities. This in turn was to give rise to an output of academic writings, which can be classified under two broad headings: dissertations
(and research articles) and essays. The essays published after 1960 tended to be principally concerned with three broad themes: social and political questions, literary criticism, philosophy and the epistemology of human sciences. Having outlined these subject areas, the present article examines
the central role played by these essayists in the intellectual debate at that time, commenting in particular on their attitude towards Senghor's established views of Ngritude as well as the opinion of the university institution.
L'essai africain au fminin: parcours thmatique
Authors: Alonso Josefina Bueno , Narbona Inmaculada Daz
Published: April 2006

The expansion of women's literature has heralded a new period within the literary history of North and Sub-Saharan Africa. The writing processes and the themes dealt with by these women authors, particularly since the 1980s, point to a significant change in the total literary output
of the new literary generations of the continent. If women's fiction has clearly become a necessary point of reference, from both the production and the reception points of view, it seems appropriate that the important body of non-fictional writings (i.e. essays) that has appeared in recent
years should be examined. This article analyses the essays of women authors as well as minority writings that show the basic axes along which the search for identity is constructed, a search marked by the female condition and its postcolonial background. These reflections on female itineraries
will hopefully help define and describe the type of discourse which, far from rejecting claims of identity, tries to point out the pitfalls and obstacles it must negotiate today.
Process evaluation in research management
Authors: Gibbons Michael , Bjarnason Svava
Published: April 2006

This article examines the growth of process evaluation in two different contexts: the Academy of Finland and North West University in South Africa. Comparing and contrasting the approaches using the theoretical concepts that lie behind the differentiation of Mode 1 and Mode 2 forms
of knowledge production throws up a number of features which have particular implications for the development of the research management function in universities and other public bodies.
Implications of international technology transfer benchmarks for developing countries
Authors: Heher A.D
Published: April 2006

International technology transfer benchmark data can be used to understand the implications of promoting technology transfer in higher education institutions in developing countries. While the data indicates that the average return, after 810 years of activity, is around 1 to 2 per
cent of the annual research expenditure, the returns are, however, characterised by high uncertainty and variability. An understanding of the nature of the returns and the dynamics of the technology transfer process is necessary for institutional and public sector managers to manage this emerging
discipline effectively. Unrealistic expectations of the returns can lead to dysfunctional policy decisions. The data presented in this article, together with a dynamic model, provides background to, and an aid to understanding, the issues, so as to promote better decision-making.
Uniform saddlepoint approximations
Authors: Jensen J. L.
Published: April 2006

The validity of the saddlepoint expansion evaluated at the pointyis considered in the limitytending to ∞. This is done for the expansions of the density and of the tail probability of the meanofni.i.d. random variables and also for the expansion of the tail probability of a compound Poisson sum, whereNis a Poisson random variable. We consider both general conditions that ensure the validity of the expansions and study the four classes of densities forX1introduced in Daniels (1954).
A note on the component lifetime estimation of a multistate monotone system through the system lifetime
Authors: Bueno Vanderlei Costa
Published: April 2006

In this paper we consider the observed lifetime of a multistate monotone system and ‘the critical lower set' which causes the system deterioration. Then, under suitable conditions, we identify the component lifetime distribution using a Newton–Kantorovic iterative procedure as in Meilijson (1981).
The extinction time of a birth, death and catastrophe process and of a related diffusion model
Authors: Brockwell P. J.
Published: April 2006

The distribution of the extinction time for a linear birth and death process subject to catastrophes is determined. The catastrophes occur at a rate proportional to the population size and their magnitudes are random variables having an arbitrary distribution with generating function d(·). The asymptotic behaviour (for large initial population size) of the expected time to extinction is found under the assumption that d(.) has radius of convergence greater than 1. Corresponding results are derived for a related class of diffusion processes interrupted by catastrophes with sizes having an arbitrary distribution function.
The maximum of a random walk whose mean path has a maximum
Authors: Daniels H. E. , Skyrme T. H. R.
Published: April 2006

This paper discusses the joint distribution of the maximum and the time at which it is attained, of a random walk whose mean path is a curvilinear trend which itself has a maximum. A typical example of such a problem is the distribution of the maximum number of infectives present during the course of an epidemic. Another example where the random walk is constrained to terminate at 0 after a given time is provided by the distribution of the strength and breaking extension of a bundle of fibres.

A diffusion approximation to the joint distribution is obtained for the general case of a Brownian bridge. In the commonest class of cases which includes the two examples mentioned, a certain integral equation has to be solved. Its solution enables the marginal distribution of the time to reach the maximum to be tabulated, and the marginal distribution of the maximum confirms the results previously obtained by Daniels (1974) and Barbour (1975). Of particular interest is the conditional expectation of the maximum for a given time of attainment which behaves asymmetrically.
An invariance principle for semi-Markov processes
Authors: McDonald D.
Published: April 2006

Let (I(t))∞t = () be a semi-Markov process with state space II and recurrent probability transition kernel P. Subject to certain mixing conditions,

where Δis an invariant probability measure for P and μb is the expected sojourn time in state b ϵΠ. We show that this limit is robust; that is, for each state b ϵ Πthe sojourn-time distribution may change for each transition, but, as long as the expected sojourn time in b is µb on the average, the above limit still holds. The kernel P may also vary for each transition as long as Δis invariant.
Multiple comparisons and sums of dissociated random variables
Authors: Barbour A. D. , Eagleson G. K.
Published: April 2006

Sufficient conditions for a sum of dissociated random variables to be approximately normally distributed are derived. These results generalize the central limit theorem for U-statistics and provide conditions which can be verified in a number of applications. The method of proof is that due to Stein (1970).
Two competing queues with linear costs and geometric service requirements: the μc-rule is often optimal
Authors: Baras J. S. , Dorsey A. J. , Makowski A. M.
Published: April 2006

A discrete-time model is presented for a system of two queues competing for the service attention of a single server with infinite buffer capacity. The service requirements are geometrically distributed and independent from customer to customer as well as from the arrivals. The allocation of service attention is governed by feedback policies which are based on past decisions and buffer content histories. The cost of operation per unit time is a linear function of the queue sizes. Under the model assumptions, a fixed prioritization scheme, known as the μc-rule, is shown to be optimal for the expected long-run average criterion and for the expected discounted criterion, over both finite and infinite horizons. Two different approaches are proposed for solving these problems. One is based on the dynamic programming methodology for Markov decision processes, and assumes the arrivals to be i.i.d. The other is valid under no additional assumption on the arrival stream and uses direct comparison arguments. In both cases, the sample path properties of the adopted state-space model are exploited.
An average-case analysis for a continuous random search algorithm
Authors: Pfeifer Dietmar
Published: April 2006

We give an upper bound for the average complexity (i.e. the expected number of steps until termination) for a continuous random search algorithm using results from renewal theory. It is thus possible to show that for a predefined accuracy ε, the average complexity of the algorithm is O(–log ε) for ε → 0 which is optimal up to a constant factor.
An inventory system for perishable commodities with random lifetime
Authors: Perry David
Published: April 2006

In this study we assume an inventory system for perishable commodities in which the lifetimes of the items stored are i.i.d. random variable with finite mean.

We utilize the analogy between this inventory system and a queueing system with impatient customers, to study the process of the lost demand, the death of the unused items and the number of items in the system.
The cμ rule revisited
Authors: Buyukkoc C. , Varaiya P. , Walrand J.
Published: April 2006

The cμ rule is optimal for arbitrary arrival processes provided that the service times are geometric and the service discipline is preemptive.
Comportement asymptotique des marches aleatoires associees aux polynomes de Gegenbauer et applications
Authors: Gallardo Leonard
Published: April 2006

Random walks on N associated with orthogonal polynomials have properties similar to classical random walks on . In fact such processes have independent increments with respect to a hypergroup structure on with a convolution and a Fourier transform which is the basic tool for their study. We illustrate these ideas by giving a description of the asymptotic behaviour (CLT and ILL) of the random walks associated with Gegenbauer's polynomials. Moreover we can then use these random walks as a reference scale to deduce asymptotic properties of other Markov chains on via a comparison theorem which is of independent interest.
Densities for stationary random sets and point processes
Authors: Weil Wolfgang , Wieacker John A.
Published: April 2006

For certain stationary random sets X, densities Dφ (X) of additive functionals φ are defined and formulas for are derived when K is a compact convex set in . In particular, for the quermassintegrals and motioninvariant X, these formulas are in analogy with classical integral geometric formulas. The case where X is the union set of a Poisson process Y of convex particles is considered separately. Here, formulas involving the intensity measure of Y are obtained.
Filtering of Markov renewal queues, III: semi-Markov processes embedded in feedback queues
Authors: Hunter Jeffrey J.
Published: April 2006

In Part I (Hunter) a study of feedback queueing models was initiated. For such models the queue-length process embedded at all transition points was formulated as a Markov renewal process (MRP). This led to the observation that the queue-length processes embedded at any of the ‘arrival', ‘departure', ‘feedback', ‘input', ‘output' or ‘external' transition epochs are also MRP. Part I concentrated on the properties of the embedded discrete-time Markov chains. In this part we examine the semi-Markov processes associated with each of these embedded MRP and derive expressions for the stationary distributions associated with their irreducible subspaces. The special cases of birth-death queues with instantaneous state-dependent feedback, M/M/1/N and M/M/1 queues with instantaneous Bernoulli feedback are considered in detail. The results obtained complement those derived in Part II (Hunter) for birth-death queues without feedback.
Testing and estimating change-points in time series
Authors: Picard Dominique
Published: April 2006

The aim of this paper is to present a few techniques which may be useful in the analysis of time series when a failure is suspected. We present two categories of tests and investigate their asymptotic properties: one, of nonparametric type, is intended to detect a general failure in spectrum; the other investigates the properties of likelihood ratio tests in parametric models which have a non-standard behaviour in this situation. Finally, we obtain the asymptotic distribution of the likelihood estimators of the change parameters.
Asymptotics of two integrals from optimization theory and geometric probability
Authors: Gates D. J.
Published: April 2006

Asymptotic series are derived for two integrals using a Gaussian identity and Laplace’s method, demonstrating an improvement over earlier methods.
A characterization of the gamma distribution
Authors: Letac Gérard
Published: April 2006

The aim of this note is to prove the following characterization.
A new integral equation for the evaluation of first-passage-time probability densities
Authors: Buonocore A. , Nobile A. G. , Ricciardi L. M.
Published: April 2006

The first-passage-time p.d.f. through a time-dependent boundary for one-dimensional diffusion processes is proved to satisfy a new Volterra integral equation of the second kind involving two arbitrary continuous functions. Use of this equation is made to prove that for the Wiener and the Ornstein–Uhlenbeck processes the singularity of the kernel can be removed by a suitable choice of these functions. A simple and efficient numerical procedure for the solution of the integral equation is provided and its convergence is briefly discussed. Use of this equation is finally made to obtain closed-form expressions for first-passage-time p.d.f.'s in the case of various time-dependent boundaries.
Stochastic majorization of random variables by proportional equilibrium rates
Authors: Shanthikumar J. George
Published: April 2006

The equilibrium raterYof a random variableYwith support on non-negative integers is defined byrY(0) = 0 andrY(n) =P[Y = n –1]/P[Y–n],Let(j= 1, …,m;i= 1,2) be 2mindependent random variables that have proportional equilibrium rates with(j= 1, …,m;i= 1, 2) as the constant of proportionality. When the equilibrium rate is increasing and concave [convex] it is shown that, …,) majorizesimplies, …,for all increasing Schur-convex [concave] functionswhenever the expectations exist. In addition if, (i= 1, 2), then
Conditions for exponential ergodicity and bounds for the decay parameter of a birth-death process
Authors: Van Doorn Erik A.
Published: April 2006

This paper is concerned with two problems in connection with exponential ergodicity for birth-death processes on a semi-infinite lattice of integers. The first is to determine from the birth and death rates whether exponential ergodicity prevails. We give some necessary and some sufficient conditions which suffice to settle the question for most processes encountered in practice. In particular, a complete solution is obtained for processes where, from some finite statenonwards, the birth and death rates are rational functions ofn. The second, more difficult, problem is to evaluate the decay parameter of an exponentially ergodic birth-death process. Our contribution to the solution of this problem consists of a number of upper and lower bounds.
Stationary control of Brownian motion in several dimensions
Authors: Cox R. Mitchell , Karatzas Ioannis
Published: April 2006

We address the question of controlling the Brownian path in several dimensions (d≧2) by continually choosing its drift from among vectors of the unit ball in ℝd. The past and present of the path are supposed to be completely observable, while no anticipation of the future is allowed. Imposing a suitable cost on distance from the origin, as well as a cost of effort proportional to the length of the drift vector, ‘reasonable’ procedures turn out to be of the following type: to apply drift of maximal length along the ray towards the origin if the current position is outside a sphere centred at the origin, and to choose zero drift otherwise. It is shown just how to compute the radius of such a sphere in terms of the data of the problem, so that the resulting procedure is optimal.
The thrown string: a Markov field approach
Authors: Willenborg Leon
Published: April 2006

A static model is proposed for a string thrown at random on a horizontal plane. The curvature of such a string is described by a Markov field that is derived from the Brownian bridge.
On the use of the deterministic Lyapunov function for the ergodicity of stochastic difference equations
Authors: Chan K. S. , Tong H.
Published: April 2006

We have shown that within the setting of a difference equation it is possible to link ergodicity with stability via the physical notion of energy in the form of a Lyapunov function.
Sequential urn schemes and birth processes
Authors: Holst Lars , Hüsler Jürg
Published: April 2006

An urn contains balls of different colours, which are randomly drawn one at a time. After each draw the number of balls in the urn with the same colour as the ball last drawn is changed. Special cases are sampling with and without replacement, and Pólya sampling. The drawing stops when a given number of colours has been drawn a given number of times. The number of times the different colours have been drawn is studied in this paper by imbedding the urn scheme in birth processes. Both exact and asymptotic results are obtained. In particular, waiting times for sampling with and without replacement and for Pólya sampling are considered.
Behaviour of χ2 processes at extrema
Authors: Aronowich M. , Adler R. J.
Published: April 2006

We study certain aspects of the sample path behaviour of χ2 processes; in particular, problems related to the behaviour of these processes at their local extrema. Emphasis is placed on behaviour that is qualitatively different to that observed for Gaussian processes, rather than on phenomena common to both classes of processes, such as previously studied (global) extremal type results.