bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative morphology of the venom apparatus in the braconid wasp subfamily Rogadinae (Insecta, Hymenoptera, Braconidae) and related taxa
Authors: Zaldivar‐Riverón A. , Areekul B. , Shaw M. R. , Quicke D. L. J.
Published: April 2004

Zaldivar‐Riverón, A., Areekul, B., Shaw, M. R. & Quicke, D. L. J. (2004). Comparative morphology of the venom apparatus in the braconid wasp subfamily Rogadinae (Insecta, Hymenoptera, Braconidae) and related taxa. —Zoologica Scripta, 33, 223–237.

The morphology of the venom apparatus intima in representatives of 38 genera of the problematic braconid wasp subfamily Rogadinae and other cyclostome braconids was investigated and a preliminary phylogenetic analysis for the group was performed with the information obtained. Despite the limited number of characters, the data suggest several relationships at various taxonomic levels. The venom apparatus in the Clinocentrini and the Stiropiini is relatively unmodified and similar to that found in other genera previously placed within a broader concept of the Rogadinae (e.g. genera of Lysitermini, Pentatermini, Tetratermini, Hormiini) and also to that of the Betylobraconinae. The presence of a cone of filaments located inside the secondary venom duct near to its insertion on the venom reservoir/primary venom duct is proposed as a synapomorphy for the tribe Rogadini to the exclusion of Stiropiini, Clinocentrini and Yeliconini. Other features of the secondary venom duct and its insertion on the venom reservoir/primary venom duct support a number of relationships between the genera of the Rogadini and also within the large genus Aleiodes. A clade containing 15 Rogadini genera (Bathoteca, Bathotecoides, Bulborogas, Canalirogas, Colastomion, Conspinaria, Cystomastacoides, Macrostomion, Megarhogas, Myocron, Pholichora, Rectivena, Rogas, Spinaria and Triraphis) is supported by the presence of a thickened and short secondary venom duct, whereas the different members of Aleiodes (excluding members of the subgenus Heterogamus) and Cordylorhogas are distinguished by having a recessed secondary venom duct with well‐defined and numerous internal filaments. New World Rogas species exhibit a unique venom apparatus and may not be closely related to the Old World ones. Features of the venom apparatus of the enigmatic genus Telengaia and the exothecine genera Shawiana and Colastes suggest that the Telengainae and Exothecinae are both closely related to the Braconinae, Gnamptodontinae, and possibly to the Opiinae and Alysiinae. An unsculptured venom reservoir was found in one specimen of the type species of Avga, A. choaspes, which is consistent with it occupying either a very basal position within the cyclostome braconids or belonging to a recently recognized ‘Gondwanan’ clade that also includes the Aphidiinae.
Phylogenetic analysis of the Balanidae (Cirripedia, Balanomorpha)
Authors: Pitombo F. B.
Published: April 2004

Pitombo, F. B. (2004). Phylogenetic analysis of the Balanidae (Cirripedia, Balanomorpha). —Zoologica Scripta, 33, 261–276.

Our concept of the family Balanidae has undergone many changes since it was originally proposed, and it is now a more circumscribed group. Nevertheless, there are no studies of the phylogenetic relationships among its currently recognized subfamilies: Balaninae, Concavinae and Megabalaninae. Here, a new suite of characters is presented, thus allowing a better evaluation of the systematics of the group. A fourth subfamily, the Amphibalaninae, is proposed to accommodate Amphibalanus gen. nov. and its allies, and Perforatus gen. nov. is proposed and transferred to the Concavinae (all formerly Balaninae). A phylogenetic analysis of the Balanidae was performed. The results showed that Balaninae is basal to the other three subfamilies as well as Concavinae, and Megabalaninae forms a monophyletic group. Hypotheses of character evolution are presented and discussed. As a general pattern, Concavinae and Megabalaninae have the most derived structures, such as the extension of the lateral margin of the sheath, inner face of radii with a longitudinal abutment, basis multilayered (vesicular) and a spur with infolded margins.
The freshwater turtle genus Mauremys (Testudines, Geoemydidae) — a textbook example of an east–west disjunction or a taxonomic misconcept?
Authors: Barth Dana , Bernhard Detlef , Fritzsch Guido , Fritz Uwe
Published: April 2004

Barth, D. Bernhard, D. Fritzsch, G. & Fritz, U. (2004): The freshwater turtle genus Mauremys— a textbook example of an east–west disjunction or a taxonomic misconcept? —Zoologica Scripta, 33, 213–221.

We compare 1036 bp of the mitochondrial cytochrome b gene (cyt b) from all six Mauremys species with 16 other taxa, representing both currently recognized subfamilies of the Geoemydidae (Geoemydinae and Batagurinae) to contribute a comprehensive dataset towards resolving the conflicting Mauremys taxonomy and phylogeography. Mauremys, a representative of the Geoemydinae, is thought to be an example of a taxon with an east–west disjunction due to Pleistocene glacial extinction, with species occurring in the western Palearctic and species in the eastern Palearctic and Oriental regions. Our results contradict this traditional zoogeographical scheme and the current taxonomy of the Geoemydidae. Mauremys is paraphyletic with respect to two East Asian genera belonging to the Batagurinae: Chinemys and Ocadia. Therefore, Mauremys, as currently understood, clearly represents a taxonomic misconcept. Mauremys+Chinemys+Ocadia contains four well supported clades, two of which —M. japonica+Chinemys+Ocadia and M. annamensis+M. mutica— are confined to eastern Asia. The other two —M. caspica+M. rivulata and M. leprosa— occur in the western Palearctic. Mauremys leprosa may represent an ancient lineage which differentiated before the split between the other western and eastern species occurred. The patchy distribution of the four clades is likely the result of several ancient radiations rather than of a Pleistocene extinction. The sister‐group of Mauremys+Chinemys+Ocadia is Cuora, a morphologically highly specialized genus with a complicated shell hinging mechanism.
Deciphering enzymes
Authors: Woycechowsky Kenneth J. , Hilvert Donald
Published: April 2004

The efficient engineering of enzymes with novel activities remains an ongoing challenge. Towards this end, genetic selection techniques provide a method for finding rare solutions to catalytic problems that requires only a limited foreknowledge of structure–function relationships. We have used genetic selections to extensively probe the structure and mechanism of chorismate mutases. The insights gained from these investigations will aid future enzyme design efforts.
Single phosphorylation of Tyr304 in the cytoplasmic tail of ephrin B2 confers high‐affinity and bifunctional binding to both the SH2 domain of Grb4 and the PDZ domain of the PDZ‐RGS3 protein
Authors: Su Zhengding , Xu Ping , Ni Feng
Published: April 2004

The B class cell‐attached ephrins mediate contact‐dependent cell–cell communications and transduce the contact signals to the host cells through the binding interactions of their cytoplasmic domains. Two classes of intracellular effectors of B ephrins have been identified: one contains the PSD‐95/Dlg/ZO‐1 (PDZ) domain (for example PDZ‐RGS3), and the second the Src homology 2 (SH2) domain (e.g. the Grb4 adaptor protein). The interaction with Grb4 requires phosphorylation of tyrosine residues on the conserved cytoplasmic C‐terminal region of B ephrins, while binding to the PDZ domain is independent of tyrosine phosphorylation. However, the exact phosphorylation site(s) required for signaling remained obscure and it is also unknown whether the two classes of effectors can bind to B ephrins simultaneously or if the binding of one affects the binding of the other. We report here that phosphorylation of Tyr304 in the functional C‐terminal region (residues 301–333) of ephrin B2 confers high‐affinity binding to the SH2 domain of the Grb4 protein. Tyrosine phosphorylation at other candidate sites resulted in only minor change of the binding of Tyr304‐phosphorylated ephrin B peptide (i.e. ephrinB2(301–333)‐pY304) with the SH2 domain. 1H‐15N NMR HSQC experiments show that only the ephrinB2(301–333)‐pY304 peptide forms a stable and specific binding complex with the SH2 domain of Grb4. The SH2 and PDZ domains were found to bind to the Tyr304 phosphopeptide both independently and at the same time, forming a three‐component molecular complex. Taken together, our studies identify a novel SH2 domain binding motif, PHpY304EKV, on the cytoplasmic domains of B ephrins that may be essential for reverse signaling via the Grb4 adaptor protein alone or in concert with proteins containing PDZ domains.
Market Sharing Agreements and Collusive Networks*
Authors: Belleflamme Paul , Bloch Francis
Published: April 2004

We analyze reciprocal market sharing agreements by which firms commit not to enter each other's territory in oligopolistic markets and procurement auctions. The set of market sharing agreements defines a collusive network. We characterize stable collusive networks when firms and markets are symmetric. Stable networks are formed of complete alliances, of different sizes, larger than a minimal threshold. Typically, stable networks display fewer agreements than the optimal network for the industry and more agreements than the socially optimal network. When firms or markets are asymmetric, stable networks may involve incomplete alliances and be underconnected with respect to the social optimum.
The relationship between urinary symptom questionnaires and urodynamic diagnoses: an analysis of two methods of questionnaire administration
Authors: Khan Mohid S. , Chaliha Charlotte , Leskova Lucia , Khullar Vikram
Published: April 2004

Objective  To assess whether method of administration of a standard urinary symptom questionnaire alters the relationship of symptoms with urodynamic diagnoses.

Design  Randomised crossover study.

Setting  Tertiary Urogynaecology Unit, London, UK.

Participants  One hundred and fourteen women attending a tertiary urogynaecology clinic.

Methods  Women were randomised to either an initial interview‐assisted questionnaire in the clinic with a follow up postal questionnaire or an initial pre‐outpatient questionnaire followed by an interview‐assisted questionnaire at the clinic visit. Videocystourethrography or saline cystometry was performed at the clinic visit.

Main outcome measures  Question responses were compared with urodynamic diagnoses.

Results  With an interview method, only severity of incontinence was significantly associated with detrusor overactivity (U= 593.5, P= 0.012). With self‐completion, severity of nocturia (U= 477, P < 0.05), urgency (U= 395, P= 0.003), urge urinary incontinence (U= 392, P= 0.003), leakage without warning (U= 443, P= 0.035) and incomplete voiding (U= 413, P= 0.01) were significantly associated with detrusor activity. On interview the symptom of stress urinary incontinence (U= 523, P= 0.002) and use of pads (U= 564.5, P= 0.011) were significantly associated with a diagnosis of urodynamic stress incontinence. Severity of stress urinary incontinence (U= 276, P < 0.001), frequency of leakage (U= 348.5, P= 0.004), use of protection (U= 432.5, P < 0.018), nocturnal incontinence (U= 393.5, P= 0.002) and quantity of leakage (U= 441.5, P < 0.05) on self‐completion were strongly associated with diagnosed urodynamic stress incontinence. There was no association between the symptoms of urgency or urge incontinence and the urodynamic stress incontinence.

Conclusions  Postal questionnaire responses have a better relationship with urodynamics, both for urodynamic stress incontinence and detrusor over activity, than interview‐assisted questionnaire responses. However, no symptom has a high enough specificity and sensitivity to replace urodynamic testing.
Promotion of Safety Helmets for Child Bicyclists
Authors: Coffman Sherrilyn
Published: April 2004

(1) Bicycle‐related injuries account for a significant number of emergency department visits each year, and head injuries are a frequent cause of disability and death in children. Because safety helmets have been demonstrated to decrease the rate of head injuries, helmet promotion programs, including education, helmet subsidies and legislation, have received increased attention. This review summarizes the studies which have evaluated the effectiveness of helmet promotion programs. Research demonstrates that legislation, combined with education and helmet subsidies, is the most effective strategy to increase use of safety helmets in child bicyclists.
Predictors of Maternal‐Fetal Attachment: An Integrative Review
Authors: Erickson Margaret
Published: April 2004

(1) Extensive studies have been conducted that explore the mother‐infant relationship from the perspective of maternal attachment but limited research has been conducted on maternal‐fetal attachment. In this integrative review the current state of knowledge on prenatal attachment is examined. Next predictors of maternal‐fetal attachment that have been found and supported by scientific research are explored. Finally, practice and research implications based on analysis of the current status of maternal‐fetal attachment are identified.
Feeding Tube Placement Verification Using Gastric pH Measurement
Authors: Chen Carol A. , Paxton Patricia , Williams‐Burgess Christine
Published: April 2004

The importance of nutrition in hospitalized patients cannot be underestimated. Proper nutrition is necessary for wound healing, recovery, reduction in morbidity, and consequent reductions in lengths of stay and mortality. Enteral nutrition, preferred over parenteral nutrition because of decreased bacterial translocation and reduced expense, is frequently delivered via a feeding tube. However, improper position of the feeding tube may result in pulmonary aspiration. Many of the methods currently employed in the verification of feeding tube placement are unreliable.
A Comparison of the Effectiveness of Pharmacologic Treatment of Otitis Media with Effusion in Children: Integrative and Meta‐Analysis
Authors: Witmer Annemarie , Wells April M. , Seymour Rosalee J.
Published: April 2004

(1) The treatment of otitis media with effusion is controversial and has inconsistent variations of pharmacotherapeutic practices. Current pharmacologic practices include use of antibiotics, antihistamine and/or decongestants, or a combination of antibiotics with antihistamine and/or decongestants. The effectiveness of these treatment protocols was examined through an integrative and meta‐analysis of published research. Data was collected from research published over a 17 year period from 1980 to 1997. The hypothesis is that children, ages three months to 12 years, with otitis media with effusion who are untreated will demonstrate successful resolution of effusion equal to those treated with pharmacologic agents (P< 0.05). The integrative and meta‐analytic results reject this hypothesis, as pharmacologic treatment is statistically significant in its resolution when compared to no treatment (Pd=0.0017). However, there is a weak effect size (R=0.07).
Update: Assessment of Gastric pH in the Critically Ill
Authors: Neill Kathleen M. , Rice Kathleen T. , Ahern Helen L.
Published: April 2004

(1) The purpose of this manuscript is to update a review of the measurement of intraluminal gastric pH in the critically ill. Intraluminal gastric pH is readily measured by aspirates tested with litmus paper or a nasogastric tube with an antimony or glass electrode tip. Significant variations of intragastric pH have been shown in different stomach locations. Significant variations in the accuracy of pH readings have also been demonstrated. Prophylactic therapy in the critically ill is aimed at maintaining a gastric pH greater than 4.0 by drug therapy that 1) neutralizes acid, 2) interrupts the signal to produce acid, 3) reduces the amount of acid produced, or 4) enhances the mucosal barrier of the stomach lining. The critically ill patients at risk of respiratory failure or coagulopathy are the patients most at risk of gastrointestinal bleeding and are, therefore, the ones most likely to benefit from prophylactic therapy. Multiple pH readings are more reliable indicators of gastric pH than are individual readings. Continuous prophylaxis is more effective than intermittent.
Understanding and Consulting to Family Business Boards
Authors: Alderfer Clayton P.
Published: April 2004

When the boards of family firms are active, their properties as groups shape the authority of the chief executive and the quality of advice that directors provide to management. An understanding of the group dynamics of the board and the board-management relationship helps to reach a satisfactory balance between family concerns and company interests. Boards of directors can improve their value to firms and to individual directors by developing a capacity for self-reflection.
Commentary on Legal Liability: Organizing the Advisory Council
Authors: Tillman Fred A.
Published: April 2004

Although we cannot predict the outcome of uncertain legal issues, it is possible that advisory councils face less legal liability than boards of directors. The key to minimizing the risk is to keep the council separate from the board.
Managerial Practices That Support Interpreneurship and Continued Growth
Authors: Poza Ernesto J.
Published: April 2004

How do owners arrest the natural product and life cycle decline in their business and revitalize it generation after generation?
Tracking Strategy in an Entrepreneurial Firm
Authors: Mintzberg Henry , Waters James A.
Published: April 2004

This study tracks the strategies of a retail chain over sixty years of its history to show how that vague concept called strategy can be operationalized and to draw conclusions about strategy formation in the entrepreneurial firm that grows large and formalizes its structure. The conclusions focus on patterns of strategic change and on contrasting characteristics of entrepreneurship and planning.
The Impact of Family Dynamics on Structure and Process in Family Foundations
Authors: Gersick Kelin E. , Lansberg Ivan , Davis John A.
Published: April 2004

This article presents the findings of an interview case study of six family foundations. The study explored the impact of family dynamics on organizational structure, grant-making procedures, board continuity, and board and staff interaction. The core finding was that developmental stage—as measured by generation, beginning with the founder—is of critical importance in understanding the operations of family foundations. The article concludes with a series of hypotheses for future research.
Penetrating the Cycle of Sustained Conflict
Authors: Kaye Kenneth
Published: April 2004

Analysis of a family's chronic cycle of escalating and retreating from conflicts is a powerful tool for breaking the cycle, resolving conflicts, and improving relationships.
Outside Boards and Family Businesses: Another Look
Authors: Schwartz Marc A. , Barnes Louis B.
Published: April 2004

The debate over the usefulness of outside board members in family businesses goes on. Two of the three empirical studies on this issue tend to disagree on their value. Using a sample of 262 family business firms, drawn from the Business Week Newsletter for Family-Owned Businesses, this study surveyed CEOs to learn of their attitudes toward inside and outside board members. The findings strongly support the inclusion of outsiders and suggest that the more outside board members the better and the more inside family members the worse, but only where CEO desire, careful selection, and shared expectations are part of that outsider membership.
Managing a Business Interest in Trust
Authors: Lehman Mary B.
Published: April 2004

Trusts are difficult to design in the best of circumstances. They must maneuver through requirements and restrictions from several disciplines and demand great care in their wording and fiduciary management. This article explores the implications of such issues as business judgment and trustee impartiality for the use of trusts by family business owners.
Successful Ownership in Business Families
Authors: Williams Roy O.
Published: April 2004

The concept of ownership can be viewed in a narrow legal sense or from a broader perspective that encompasses knowledge, skill, integrity, responsibility, trust, and mutual consideration. When this “spirit of ownership” is achieved, the family business prospers and the family itself becomes a close-knit, effective team. This article describes some of the most important elements that can help a family with business ownership to become an effective business family.
Research Note: A Second Family Business—Patterns in Wealth Management
Authors: Hamilton Sara
Published: April 2004

This interview study provides preliminary data on the asset management behavior of families who are business owners or have recently liquidated businesses. The data address investment patterns, criteria for selecting investment managers, cash management, and investment strategy.
Research Note: The Emergence of American Indian Enterprise
Authors: Stallings Steven L. A.
Published: April 2004

We are in the early stages of what may become a dramatic transformation in economic development among Native Americans. Tribal enterprises, individual entrepreneurs, and reservation economic development corporations are beginning to attract and generate new capital and to offer hope of greater economic independence and prosperity for this sector of our society. This note presents an introduction to the characteristics of entrepreneurship and family enterprise in the Native American population.
Ethnicity and Organizational Forms: An Interview with William Ouchi
Authors: Gersick Kelin E.
Published: April 2004

Professor William Ouchi, the author of Theory Z and The M-Form Society, is one of the country's most respected authorities on comparative international management and competitiveness. In this interview, he discusses the application of his concept of the organizational clan to family enterprise, and the critical importance of ethnicity in our experience of our social environment.
Influence of Family Relationships on Succession Planning and Training: The Importance of Mediating Factors
Authors: Lansberg Ivan , Astrachan Joseph H.
Published: April 2004

This study models the influence of family relationships on succession variables, using a sample of 130 participants from 109 family businesses. Results suggest that the effects of family adaptability and family cohesion on succession planning and successor training are determined by the family'S commitment to the business and the quality of the owner-manager and successor relationship. The study finds that the influence of family relationships on administrative behavior in family businesses is not always direct, as was previously assumed, but is mediated by various factors.
Family Business and Multiple Levels of Conflict
Authors: Harvey Michael , Evans Rodney E.
Published: April 2004

Family businesses are fertile fields for conflict. The influence of the founding families on the basic tenets and culture of the company may be unparalleled in business. When attempts are made to modify the family business as it progresses to another stage of development, conflict may arise. Due to the verlay of the company culture and individual family units, the means to resolve conflict becomes a very intricate process. This article examines a means to predict conflict relative to the phases of development of a family business. In addition, multiple levels of conflict are examined as well as the appropriate resolution process for the differing levels of conflict.
Developing Leadership in the Successor Generation
Authors: Foster Alicia Turner
Published: April 2004

The cross-disciplinary nature of family business studies suggests the opportunity to consider theories and applications from a variety of disciplines in order to examine how they might be applied to family business. This article is an exploratory examination of how the Center for Creative Leadership's research in the field of leadership might add to the knowledge and hypotheses regarding leadership in family businesses.

The goal is to outline strategies for developing leadership that practitioners might find useful in their work with families around succession opportunities. Additionally, the hope is to spark discussion and thinking around the possible application of a leadership development model to the successor generation in family businesses.
The Estate Tax Drag on Family Businesses
Authors: Foster J.D. , Fleenor Patrick
Published: April 2004

This essay considers estate taxes and their effect upon entrepreneurial activity and family business. After a brief history of estate taxes, estate compositions and tax burdens are addressed. Finally, a simulation model is used to quantify the disincentive effect of estate taxation upon wealth accumulation. The simulation model suggests that estate taxes have the same disincentive effect as would a 67% individual tax rate or a 67.85% corporate tax rate. Thus, it would be necessary to roughly double the individual and corporate tax rates to reduce bequests to the level under the current estate tax regime.
The Effect of Estate Taxes on Family Business: Survey Results
Authors: Astrachan Joseph H. , Tutterow Roger
Published: April 2004

A survey of 1,003 businesses examined the effect of estate taxes on family business behavior, including investment, employment, and strategic decisions. The results strongly suggest that estate taxes have marked effects on business behavior. These effects are more pronounced in larger firms where their potential impact is of a greater magnitude.
Research Note: Comparison of Small Businesses with Family Participation versus Small Businesses Without Family Participation: An Investigation of Differences in Goals, Attitudes, and Family/Business Conflict
Authors: Lee Myung-Soo , Rogoff Edward G.
Published: April 2004

This study investigates three important issues in a family business: (1) Whether there is a significant difference, relative to their goals and attitudes, between owners of businesses with family participation and owners of businesses without family participation; (2) whether owners of businesses with family participation perceive higher levels of business-family conflict than owners of businesses without family participation; and (3) whether owners of businesses with family participation view business-family conflict as a significant impediment to their business performance. We conducted a survey of 231 small business owners in midsize cities in the northeastern and midwestern United States. Of the total sample, 118 are businesses in which two or more family members are employed. This study examines both the reported conflict and the positives of family-member involvement. The findings indicate that there is no overall difference in business-related goals between the two groups, but that owners of businesses with family participation do experience significantly more business-family conflict. The study also concludes that this conflict is generally well managed and does not interfere with business objectives. In fact, the authors conclude that owners of businesses with family participation see the involvement of family members as a positive. Managerial implications and research suggestions are also discussed.
Analysis of a Hydrodynamic Bearing of a HDD Spindle Motor at Elevated Temperature
Authors: Jang G. H. , Kim K. S. , Lee H. S. , Kim C. S.
Published: April 2004

This paper presents a method to investigate the characteristics of hydrodynamic bearings of a HDD spindle motor considering the variation of the clearance as well as the lubricant viscosity due to elevated temperature. Iterative finite element analysis of heat conduction and thermal deformation is performed to determine the viscosity and clearance of hydrodynamic bearings at elevated temperature until the temperature in the bearing area converges. The proposed method is verified by comparing the calculated temperature with the measured one at elevated surrounding temperature as well as in room temperature. This research shows that elevated temperature changes the clearance as well as the lubricant viscosity of the hydrodynamic bearings of a HDD spindle motor. Once the viscosity and clearance of hydrodynamic bearings of a HDD spindle motor are determined, finite element analysis of the Reynolds equation is performed to investigate the static and dynamic characteristics of hydrodynamic bearings of a HDD spindle motor at elevated temperature. It also shows that the variation of clearance due to elevated temperature is another important design consideration which affects the static and dynamic characteristics of the hydrodynamic bearings of a HDD spindle motor.
Effect of number of masking talkers and auditory priming on informational masking in speech recognition
Authors: Freyman Richard L. , Balakrishnan Uma , Helfer Karen S.
Published: April 2004

Three experiments investigated factors that influence the creation of and release from informational masking in speech recognition. The target stimuli were nonsense sentences spoken by a female talker. In experiment 1 the masker was a mixture of three, four, six, or ten female talkers, all reciting similar nonsense sentences. Listeners’ recognition performance was measured with both target and masker presented from a front loudspeaker (F–F) or with a masker presented from two loudspeakers, with the right leading the front by 4 ms (F–RF). In the latter condition the target and masker appear to be from different locations. This aids recognition performance for one- and two-talker maskers, but not for noise. As the number of masking talkers increased to ten, the improvement in the F–RF condition diminished, but did not disappear. The second experiment investigated whether hearing a preview (prime) of the target sentence before it was presented in masking improved recognition for the last key word, which was not included in the prime. Marked improvements occurred only for the F–F condition with two-talker masking, not for continuous noise or F–RF two-talker masking. The third experiment found that the benefit of priming in the F–F condition was maintained if the prime sentence was spoken by a different talker or even if it was printed and read silently. These results suggest that informational masking can be overcome by factors that improve listeners’ auditory attention toward the target.
Rapid calculations of time-harmonic nearfield pressures produced by rectangular pistons
Authors: McGough Robert J.
Published: April 2004

A rapid method for calculating the nearfield pressure distribution generated by a rectangular piston is derived for time-harmonic excitations. This rapid approach improves the numerical performance relative to the impulse response with an equivalent integral expression that removes the numerical singularities caused by inverse trigonometric functions. The resulting errors are demonstrated in pressure field calculations using the time-harmonic impulse response solution for a rectangular source 5 wavelengths wide by 7.5 wavelengths high. Simulations using this source geometry show that the rapid method eliminates the singularities introduced by the impulse response. The results of pressure field computations are then evaluated in terms of relative errors and computational speeds. The results show that, when the same number of Gauss abscissas are applied to both approaches for time-harmonic pressure field calculations, the rapid method is consistently faster than the impulse response, and the rapid method consistently produces smaller maximum errors than the impulse response. For specified maximum error values of 10% and 1%, the rapid method is 2.6 times faster than the impulse response for pressure field calculations performed on a 61 by 101 point grid. The rapid approach achieves even greater reductions in the computation time for smaller errors and larger grids.
Analysis of transient Lamb waves generated by dynamic surface sources in thin composite plates
Authors: Banerjee Sauvik , Mal Ajit K. , Prosser William H.
Published: April 2004

A theoretical analysis is carried out in an effort to understand certain unusual properties of transient guided waves produced in a thin unidirectional graphite/epoxy composite plate by a localized dynamic surface load. The surface motion is calculated using an approximate plate theory, called the shear deformation plate theory (SDPT), as well as a recently developed finite element analysis (FEA), for their mutual verification. The results obtained by the two methods are shown to have excellent agreement. An interesting, nearly periodic “phase reversal” of the signal with propagation distance is observed for each propagation direction relative to the fiber direction. For clarification, a closed form analytical expression for the vertical surface displacement in an aluminum plate to an impulsive point force is obtained using the steepest descent method. It is found that the strong dispersion of the first antisymmetric waves at low frequencies is the main reason behind the phase reversal. This is verified further by measuring the surface response of a relatively thick aluminum plate to a pencil lead break source. The understanding developed in the paper is expected to be helpful in detecting and characterizing the occurrence of damage in composite structures.
Nonlinear waveform distortion and shock formation in the near field of a continuous wave piston source
Authors: Sapozhnikov Oleg A. , Khokhlova Vera A. , Cathignol Dominique
Published: April 2004

A classical effect of nonlinear acoustics is that a plane sinusoidal acoustic wave propagating in a nonlinear medium transforms to a sawtooth wave with one shock per cycle. However, the waveform evolution can be quite different in the near field of a plane source due to diffraction. Previous numerical simulations of nonlinear acoustic waves in the near field of a circular piston source predict the development of two shocks per wave cycle [Khokhlova et al., J. Acoust. Soc. Am. 110, 95–108 (2001)]. Moreover, at some locations the peak pressure may be up to 4 times the source amplitude. The motivation of this work was to experimentally verify and further explain the phenomena of the nonlinear waveform distortion. Measurements were conducted in water with a 47-mm-diameter unfocused transducer, working at 1-MHz frequency. For pressure amplitudes higher than 0.5 MPa, two shocks per cycle were observed in the waveform beyond the last minimum of the fundamental harmonic amplitude. With the increase of the observation distance, these two shocks collided and formed one shock (per cycle), i.e., the waveform developed into the classical sawtooth wave. The experimental results were in a very good agreement with the modeling based on the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation.
A closed form solution for the mobility of an edge-excited, semi-infinite plate
Authors: Su J. X. , Moorhouse A. T.
Published: April 2004

Closed form analytical solutions are given for the point force and point moment mobilities at the free edge of a semi-infinite plate. Previously, these solutions have been known only in terms of unsolved integrals. The solutions give mobility as functions of Poisson’s ratio times the characteristic mobility. The edge-excited plate therefore can be added to the relatively small number of structures for which exact solutions are available. The value of such solutions lies in allowing computer simulations, and testing for approximate methods.
TWO- AND THREE-PHOTON NONLINEAR ABSORPTION IN As2Se3 CHALCOGENIDE GLASS: THEORY AND EXPERIMENT
Authors: SANCHEZ F. , BOUDEBS G. , CHERUKULAPPURATH S. , LEBLOND H. , TROLES J. , SMEKTALA F.
Published: April 2004

The absorption of a monochromatic plane wave in a medium exhibiting linear, two- and three-photon absorption is investigated theoretically. An approximate closed-form expression is derived for the optical intensity. An effective two-photon absorption coefficient is then defined. Using the theoretical results, the absorption coefficients from transmission measurements are determined. Experiment is done in a highly absorbing nonlinear material such as As 2 Se 3 to illustrate our theoretical results. Good agreement is found between experimental data and numerical simulation based on our model. Measurements of nonlinear coefficients characterizing the two- and three-photon absorption are given.
Pulmonary V̇o2 dynamics during treadmill and arm exercise in peripheral arterial disease
Authors: Bauer Timothy A. , Brass Eric P. , Nehler Mark , Barstow Thomas J. , Hiatt William R.
Published: April 2004

Slowed pulmonary O2 uptake (V̇o2) kinetics in peripheral arterial disease (PAD) have been attributed to impaired limb blood flow and/or peripheral muscle metabolic abnormalities. Although PAD results from atherosclerotic occlusive disease in the arteries to the lower extremities, systemic abnormalities affecting whole body O2 delivery or vascular function in PAD could also partially explain the exercise impairment. To date, the effects of these systemic abnormalities have not been evaluated. To test the hypothesis that the slowed pulmonary V̇o2 kinetics in PAD reflects local and not systemic abnormalities, V̇o2 kinetics were evaluated after the onset of constant-load exercise of the upper and lower limbs in PAD patients and healthy controls (Con). Ten PAD patients and 10 Con without significant cardiopulmonary dysfunction performed multiple transitions from rest to moderate-intensity arm ergometry and treadmill exercise to assess their V̇o2 kinetic responses. Reactive hyperemic (RH) blood flow was assessed in the arms and legs as a measure of endothelial function. Compared with Con, PAD V̇o2 kinetic phase 2 time constants were prolonged during treadmill exercise (PAD 34.3 ± 9.2 s vs. Con 19.6 ± 3.5 s; P < 0.01) but not arm exercise (PAD 38.5 ± 7.5 s vs. Con 32.5 ± 9.0 s; P > 0.05). RH blood flow was significantly reduced in the legs (PAD 20.7 ± 8.3 vs. Con 46.1 ± 17.1 ml·100 ml−1·min−1; P < 0.01) and arms of PAD subjects (PAD 34.0 ± 8.6 vs. Con 50.8 ± 12.2 ml·100 ml−1·min−1; P < 0.01) compared with Con, but RH limb flow was not correlated with arm or treadmill V̇o2 kinetic responses in either group. In summary, slowed pulmonary V̇o2 kinetics in PAD patients occur only with exercise of the lower limbs affected by the arterial occlusive disease process and are not slowed with exercise of the unaffected upper extremities compared with controls. Furthermore, the slowed pulmonaryV̇o2 kinetics of the lower extremity could not be explained by any abnormalities in resting cardiac or pulmonary function and were not related to the magnitude of reduction in limb vascular reactivity.
IL-2–induced CD4+ T-cell expansion in HIV-infected patients is associated with long-term decreases in T-cell proliferation
Authors: Sereti Irini , Anthony Kara B. , Martinez-Wilson Hector , Lempicki Richard , Adelsberger Joseph , Metcalf Julia A. , Hallahan Claire W. , Follmann Dean , Davey Richard T. , Kovacs Joseph A. , Lane H. Clifford
Published: April 2004

Administration of interleukin 2 (IL-2) leads to selective and sustained CD4+ T-cell expansions in patients infected with HIV. It has been hypothesized that persistent CD4+ T-cell proliferation is the primary mechanism maintaining these expansions. T-cell proliferation was studied by ex vivo bromodeoxyuridine (BrdU) incorporation and intracellular Ki67 staining in HIV-infected patients treated with antiretroviral therapy (ART) with or without IL-2. In contrast to the tested hypothesis, HIV-infected patients treated with IL-2 had lower CD4+ T-cell proliferation compared to patients treated with ART alone. Independently of viral load changes, administration of IL-2 led to a decrease in basal CD4+ T-cell proliferation. Total numbers of CD4+ T cells with naive and recall, but not effector, memory phenotype were increased. The degree of CD4+ T-cell expansion correlated with the decreases in proliferation and a strong association was seen between these decreases and the expansion of the CD4+/CD25+ subset. Intermittent IL-2 in HIV-infected patients leads to expansions of CD4+/CD25+ T cells with naive and recall memory phenotypes that strongly correlate with decreases in proliferation. These data suggest that decreased T-cell proliferation is central in the CD4+ T-cell expansions induced by IL-2.
An Effective TiO2 Photocatalyst Prepared under Supercritical Conditions
Authors: Li Hexing , Zhu Jian , Li Guisheng , Wan Ying
Published: April 2004

A novel porous TiO2 photocatalyst with higher surface area was prepared by sol–gel method followed by removing solvent under supercritical conditions. This catalyst exhibited higher activity and stronger durability during photocatalytic degradation of phenol than that obtained via direct drying, possibly owing to the higher surface area and crystallization degree of anatase which exhibited higher quantum yield during photocatalysis.
Display of Azido Glycoside on a Sensor Chip
Authors: Sato Toshinori , Fujita Sinya , Kasuya Maria Carmelita Z , Hatanaka Kenichi , Yamagata Tatsuya
Published: April 2004

Using 12-azidododecyl β-mannoside, we successfully immobilized azido glycoside onto a sensor chip by either the Staudinger reaction or reduction of azido group followed by condensation reaction. Specific binding of Concanavalin A to the sensor chip proved immobilization of the glycoside by either method.
A Chiral Pybox Ligand as a New Chiral Shift Reagent for Secondary Dialkylammonium Cations
Authors: Sada Kazuki , Tateishi Yuichi , Shinkai Seiji
Published: April 2004

A new chiral shift reagent, a C2 chiral phenylpybox ligand, targeted for secondary dialkylammonium cations has been exploited.
Direct Synthesis and Spectroscopic Evidence of Framework Co(II) ions in SBA-15 Mesoporous Molecular Sieves
Authors: Vinu Ajayan , Hartmann Martin
Published: April 2004

CoSBA-15 with different nSi/nCo ratio have been synthesized in acidic media using nonionic surfactants and characterized, for the first time, by XRD, AAS, N2 adsorption, UV–vis DRS and ESR spectroscopy. Spectroscopic data show that all cobalt atoms in CoSBA-15 are extensively in tetrahedral coordination.
Double Nucleophilic Addition of Azide and Tetramethallyltin to α,β-Unsaturated Aldimines Promoted by Aluminum Chloride
Authors: Shimizu Makoto , Yamauchi Chiaki , Ogawa Toshiki
Published: April 2004

In the presence of AlCl3, a mixture of hydrogen azide and tetramethallyltin underwent 1,4- and subsequently 1,2-addition, respectively, with α,β-unsaturated aldimines to give 1,3-amino azides in good yields. The 1,3-amino azides thus obtained were readily converted into 1,3-diamines by reduction with LiAlH4.
The Group Control Catastrophe
Authors: Whitmeyer Joseph M.
Published: April 2004

This study elaborates a surprising finding by Heckathorn (1990). His simulation of group-mediated social control models a situation in which an agent outside a group tries to obtain compliance by group members through the administration of sanctions. In general, group compliance increases as the agent's monitoring efficacy increases. The surprising finding is that under certain conditions group compliance collapses to zero for intermediate values of the monitoring efficacy. In this study I show this is part of a catastrophe, a bifurcation into two equilibria for intermediate values of the monitoring efficacy. Whether the group exists at a high-compliance or low-compliance equilibrium depends on the occurrence of simultaneous non-payoff-maximizing cooperation or defection. Cooperation pushes the group to the high-compliance equilibrium; defection knocks it to the low-compliance equilibrium. The catastrophe is robust: it exists for a range of parameter values and for different production functions for the public good (benefits from group compliance).
Fundamentals of Mesostructuring Through Evaporation‐Induced Self‐Assembly
Authors: Grosso D. , Cagnol F. , Soler‐Illia G. J. de A. A. , Crepaldi E. L. , Amenitsch H. , Brunet‐Bruneau A. , Bourgeois A. , Sanchez C.
Published: April 2004

This article gives an overall view of the mechanisms involved in the mesostructuring that takes place during the formation of surfactant‐templated inorganic materials by evaporation. Since such a method of preparation is well suited to fabricating thin films by dip coating, spin coating, casting, or spraying, it is of paramount interest to draw a general description of the processes occurring during the formation of self‐assembled hybrid organic/inorganic materials, taking into account all critical parameters. The following study is based on very recent works on the meso‐organization of thin silica films using tetraethylorthosilicate (TEOS) as the inorganic source and cetyltrimethylammonium bromide (CTAB) as the structuring agent, but we will show that the method can also be extended to other systems based on non‐silica oxides and block copolymer surfactants. We demonstrate that the organization depends mainly on the chemical composition of the film when it reaches the modulable steady state (MSS), where the inorganic framework is still flexible and the composition is stable after reaching an equilibrium in the diffusion of volatile species. This MSS state is generally attained seconds after the drying line, and the film's composition depends on various parameters: the relative vapor pressures in the environment, the evaporation conditions, and the chemical conditions in the initial solution. Diagrams of textures, in which the stabilized structures are controlled by local minima, are proposed to explain the complex phenomena associated with mesostructuring induced by evaporation.
A Semiparametric Estimator of the Crossing Point in the Two‐Sample Linear Shift Function: Application to Crossing Lifetime Distributions
Authors: Wu Chi‐tsung
Published: April 2004

LetXandYbe two random variables with continuous distribution functionsFandG. Consider two independent observationsX1, … ,XmfromFandY1, … ,YnfromG. Moreover, suppose there exists a uniquex* such thatF(x) >G(x) forx<x* andF(x) x* or vice versa. A semiparametric model with a linear shift function (Doksum, 1974) that is equivalent to a location‐scale model (Hsieh, 1995) will be assumed and an empirical process approach (Hsieh, 1995) is used to estimate the parameters of the shift function. Then, the estimated shift function is set to zero, and the solution is defined to be an estimate of the crossing‐pointx*. An approximate confidence band of the linear shift function at the crossing‐pointx* is also presented, which is inverted to yield an approximate confidence interval for the crossing‐point. Finally, the lifetime of guinea pigs in days observed in a treatment‐control experiment in Bjerkedal (1960) is used to demonstrate our procedure for estimating the crossing‐point. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fit and Frailties in Proportional Hazards Regression
Authors: Stare Janez , O'Quigley John
Published: April 2004

We exploit a conjectured equivalence between proportional hazards models with frailties and a particular subclass of non proportional hazards models, specifically those with declining effects, to address the question of fit. A goodness of fit test of the proportional hazards assumption against an alternative of declining regression effect is equivalent to a test for the presence of frailties. Such tests are now widely available in standard software. Although a number of tests of the proportional hazards assumption have been developed there is no test that directly formulates the alternative in terms of a non‐specified monotonic decline in regression effect and that enables a quantification of this in terms of a simple index. The index we obtain lies between zero and one such that, for any given set of covariates, values of the index close to one indicate that the fit cannot essentially be improved by allowing the possibility of regression effects to decline. Values closer to zero and away from one indicate that the fit can be improved by relaxing the proportional hazards constraint in this particular direction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)