bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel erythrocytosis-associated PHD2 mutation suggests the location of a HIF binding groove
Authors: Percy Melanie J. , Furlow Paul W. , Beer Philip A. , Lappin Terence R. J. , McMullin Mary Frances , Lee Frank S.
Published: June 2007

The molecular basis of the erythrocytosis group of red cell disorders is incompletely defined. Some cases are due to dysregulation of erythropoietin (Epo) synthesis. The hypoxia inducible transcription factor (HIF) tightly regulates Epo synthesis. HIF in turn is regulated through its α subunit, which under normoxic conditions is hydroxylated on specific prolines and targeted for degradation by the von Hippel Lindau (VHL) protein. Several mutations in VHL have been reported in erythrocytosis, but only 1 mutation in the HIF prolyl hydroxylase PHD2 (prolyl hydroxylase domain protein 2) has been described. Here, we report a novel PHD2 mutation, Arg371His, which causes decreased HIF binding, HIF hydroxylase, and HIF inhibitory activities. In the tertiary structure of PHD2, Arg371 lies close to the previously described Pro317Arg mutation site. These findings substantiate PHD2 as a critical enzyme controlling HIF and therefore Epo in humans, and furthermore suggest the location of an active site groove in PHD2 that binds HIF.
Mouse oocytes fertilised by ICSI during in vitro maturation retain the ability to be activated after refertilisation in metaphase II and can generate Ca2+oscillations
Authors: Jędrusik Agnieszka , Ajduk Anna , Pomorski Paweł , Maleszewski Marek
Published: June 2007

Background

At fertilisation, mammalian oocytes are activated by oscillations of intracellular Ca2+ ([Ca2+]i). Phospholipase Cζ, which is introduced by fertilising spermatozoon, triggers [Ca2+]i oscillations through the generation of inositol 1,4,5-triphosphate (IP3), which causes Ca2+ release by binding to IP3 receptors located on the endoplasmic reticulum (ER) of the oocyte. Ability to respond to this activating stimulus develops during meiotic maturation of the oocyte. Here we examine how the development of this ability is perturbed when a single spermatozoon is introduced into the oocyte prematurely, i.e. during oocyte maturation.

Results

Mouse oocytes during maturation in vitro were fertilised by ICSI (intracytoplasmic sperm injection) 1 – 4 h after germinal vesicle break-down (GVBD) and were subsequently cultured until they reached metaphase II (MII) stage. At MII stage they were fertilised in vitro for the second time (refertilisation). We observed that refertilised oocytes underwent activation with similar frequency as control oocytes, which also went through maturation in vitro, but were fertilised only once at MII stage (87% and 93%, respectively). Refertilised MII oocytes were able to develop [Ca2+]i oscillations in response to penetration by spermatozoa. We found however, that they generated a lower number of transients than control oocytes. We also showed that the oocytes, which were fertilised during maturation had a similar level of MPF activity as control oocytes, which were not subjected to ICSI during maturation, but had reduced level of IP3 receptors.

Conclusion

Mouse oocytes, which were experimentally fertilised during maturation retain the ability to generate repetitive [Ca2+]i transients, and to be activated after completion of maturation.
Selective stimulation of catecholamine release from bovine adrenal chromaffin cells by an ionotropic purinergic receptor sensitive to 2-methylthio ATP
Authors: Tomé Ângelo R , Castro Enrique , Santos Rosa M , Rosário Luís M
Published: June 2007

Background

2-Methylthioadenosine 5'-triphosphate (2-MeSATP), formerly regarded as a specific P2Y (metabotropic) purinergic receptor agonist, stimulates Ca2+influx and evokes catecholamine release from adrenal chromaffin cells. These cells express P2Y and P2X (ionotropic) purinoceptors, with the latter providing an important Ca2+influx pathway. Using single cell calcium imaging techniques, we have determined whether 2-MeSATP might be a specific P2X receptor agonist in bovine chromaffin cells and assessed the relative role of P2X and P2Y receptors on catecholamine secretion from these cells.

Results

ATP raised the [Ca2+]iin ~50% of the cells. Removing extracellular Ca2+suppressed the [Ca2+]i-raising ability of 2-MeSATP, observed in ~40% of the ATP-sensitive cells. This indicates that 2-MeSATP behaves as a specific ionotropic purinoceptor agonist in bovine chromaffin cells. The 2-MeSATP-induced [Ca2+]i-rises were suppressed by PPADS. UTP raised the [Ca2+]iin ~40% of the ATP-sensitive cells, indicating that these expressed Ca2+-mobilizing P2Y receptors. UTP-sensitive receptors may not be the only P2Y receptors present, as suggested by the observation that ~20% of the ATP-sensitive pool did not respond to either 2-MeSATP or UTP. The average sizes of the ATP- and 2-MeSATP-evoked [Ca2+]iresponses were identical in UTP-insensitive cells. 2-MeSATP stimulated Ca2+influx and evoked catecholamine release, whereas UTP elicited Ca2+release from intracellular stores but did not evoke secretion. 2-MeSATP-induced secretion was strongly inhibited by Cd2+and suppressed by extracellular Ca2+or Na+removal. TTX inhibited 2-MeSATP-evoked secretion by ~20%.

Conclusion

2-MeSATP is a specific P2X purinoceptor agonist and a potent secretagogue in bovine chromaffin cells. Activation of 2-MeSATP-sensitive receptors stimulates Ca2+influx mainlyviavoltage-sensitive Ca2+channels. For the most part, these are activated by the depolarization brought about by Na+influx across P2X receptor pores.
The interactive role of type 2 diabetes mellitus and E-selectin S128R mutation on susceptibility to coronary heart disease
Authors: Abu-Amero Khaled K , Al-Mohanna Futwan , Al-Boudari Olayan M , Mohamed Gamal H , Dzimiri Nduna
Published: June 2007

Background

The role of gene-environment interactions as risk factors for coronary heart disease (CAD) remains largely undefined. Such interactions may involve gene mutations and disease conditions such as type 2 diabetes mellitus (DM2) predisposing individuals to acquiring the disease.

Methods

In the present study, we assessed the possible interactive effect of DM2 and E-selectin S128R polymorphism with respect to its predisposing individuals to CAD, using as a study model a population of 1,112 patients and 427 angiographed controls of Saudi origin. E-selectin genotyping was accomplished by polymerase chain reaction (PCR) amplification followed by PstI restriction enzyme digestion.

Results

The results show that DM2 is an independent risk factor for CAD. In the absence of DM2, the presence of the R mutant allele alone is not significantly associated with CAD (p = 0.431, OR 1.28). In contrast, in the presence of DM2 and the S allele, the likelihood of an individual acquiring CAD is significant (odds ratio = 5.44; p = < 0.001). This effect of DM2 becomes remarkably greater in the presence of the mutant 128R allele, as can be observed from the odds ratio of their interaction term (odds ratio = 6.11; p = < 0.001).

Conclusion

Our findings indicate therefore that the risk of acquiring CAD in patients with DM2 increases significantly in the presence of the 128R mutant allele of the E-selectin gene.
Small primary adenocarcinoma in adenomyosis with nodal metastasis: a case report
Authors: Puppa Giacomo , Shozu Makio , Perin Tiziana , Nomura Kazuhito , Gloghini Annunziata , Campagnutta Elio , Canzonieri Vincenzo
Published: June 2007

Background

Malignant transformation of adenomyosis is a very rare event. Only about 30 cases of this occurrence have been documented till now.

Case presentation

The patient was a 57-year-old woman with a slightly enlarged uterus, who underwent total hysterectomy and unilateral adnexectomy. On gross inspection, the uterine wall displayed a single nodule measuring 5 cm and several small gelatinous lesions. Microscopic examination revealed a common leiomyoma and multiple adenomyotic foci. A few of these glands were transformed into a moderately differentiated adenocarcinoma. The endometrium was completely examined and tumor free. The carcinoma was, therefore, considered to be an endometrioid adenocarcinoma arising from adenomyosis. Four months later, an ultrasound scan revealed enlarged pelvic lymph nodes: a cytological diagnosis of metastatic adenocarcinoma was made.

Immunohistochemical studies showed an enhanced positivity of the tumor site together with the neighbouring adenomyotic foci for estrogen receptors, aromatase, p53 and COX-2 expression when compared to the distant adenomyotic glands and the endometrium. We therefore postulate that the neoplastic transformation of adenomyosis implies an early carcinogenic event involving p53 and COX-2; further tumor growth is sustained by an autocrine-paracrine loop, based on a modulation of hormone receptors as well as aromatase and COX-2 local expression.

Conclusion

Adenocarcinoma in adenomyosis may be affected by local hormonal influence and, despite its small size, may metastasize.
Comparison of children's self-reports of depressive symptoms among different family interaction types in northern Taiwan
Authors: Wu Wen-chi , Kao Chi-Hsien , Yen Lee-Lan , Lee Tony Szu-Hsien
Published: June 2007

Background

Previous research has shown that family interactions are associated with depressive symptoms in children. However, detailed classifications of family interaction types have not been studied thoroughly. This study aims to understand the types of family interactions children experience and to identify the specific types of family interactions that are associated with a higher risk of depressive symptoms in children.

Methods

Data used in the study was collected as part of the Child and Adolescent Behavior in Long term Evolution (CABLE) project in 2003. CABLE is a longitudinal cohort study that commenced in 2001 and collects data annually from children in Taipei city and Hsinchu county in northern Taiwan. The data analyzed in this study was that obtained from the sixth graders (aged 11 to 12 years old) in 2003. Of the 2,449 sixth graders, 51.2% were boys and 48.8% were girls. Factor analysis and cluster analysis were used to investigate the types of family interactions. One way ANOVA was used to establish the relationship between family interaction types and children's self-reports of depressive symptoms.

Results

Based on the results of factor analysis, the latent factors for family interactions included supporting activities, psychological control, parental discipline, behavioral supervision, and family conflict. After conducting cluster analysis using factor scores, four types of family interactions were revealed: supervised (29.66%), disciplined (13.56%), nurtured (40.96%) and conflict (15.82%). Children from the disciplined or conflict families were more likely to report depressive symptoms. Children from the nurtured families were least likely to report depressive symptoms.

Conclusion

Family interactions can be classified into four different types, which are related to children's self-reports of depressive symptoms. The creation of a family interaction environment that is beneficial for children's mental health is an important issue for health education and health promotion professionals.
Type I collagen gene suppresses tumor growth and invasion of malignant human glioma cells
Authors: Honma Kimi , Miyata Teruo , Ochiya Takahiro
Published: June 2007

Background

Invasion is a hallmark of a malignant tumor, such as a glioma, and the progression is followed by the interaction of tumor cells with an extracellular matrix (ECM). This study examined the role of type I collagen in the invasion of the malignant human glioma cell line T98G by the introduction of the human collagen type I α1 (HCOL1A1) gene.

Results

The cells overexpressing HCOL1A1 were in a cluster, whereas the control cells were scattered. Overexpression of HCOL1A1 significantly suppressed the motility and invasion of the tumor cells. The glioma cell growth was markedly inhibited in vitro and in vivo by the overexpression of HCOL1A1; in particular, tumorigenicity completely regressed in nude mice. Furthermore, the HCOL1A1 gene induced apoptosis in glioma cells.

Conclusion

These results indicate that HCOL1A1 have a suppressive biological function in glioma progression and that the introduction of HCOL1A1 provides the basis of a novel therapeutic approach for the treatment of malignant human glioma.
Markedly Impaired Fibrinolytic Balance Contributes to Cardiovascular Risk in Adults with Growth Hormone Deficiency
Authors: Devin Jessica K. , Blevins Lewis S. , Verity Denise K. , Chen Qingxia , Bloodworth John R. , Covington Joseph , Vaughan Douglas E.
Published: June 2007

Context: Adults with GH deficiency (GHD) have multiple cardiovascular risk factors, including an unfavorable lipid profile and body composition as well as impairments in endothelial function and cardiac performance. We hypothesized that GHD is associated with elevated levels of plasminogen activator inhibitor-1 (PAI-1), the major inhibitor of plasminogen activation in the circulation.

Objective: The objective of the study was to determine the fibrinolytic profile of adults with GHD in comparison with controls.

Study Design and Participants: This was a prospective, observational study including 12 adults with GHD. Twelve gender-, age-, and body mass index-matched adults served as controls.

Main Outcome Measures: The primary outcome measures were circadian plasma PAI-1 antigen with corresponding tissue-plasminogen activator (tPA) activity values. Endothelial function was assessed by flow-mediated vasodilation and fibrinolytic potential by venous occlusion test.

Results: Adults with GHD exhibited an unfavorable 24-h fibrinolytic profile characterized by a mean 62% elevation in PAI-1 antigen (2.77 ng/ml after adjustment for baseline PAI-1; P = 0.049) in the setting of a mean 24% reduction in tPA activity (−0.17 IU/ml after adjustment for baseline tPA; P = 0.003). Fibrinolytic response was defective in GHD, as demonstrated by a sustained elevation in PAI-1 activity greater than 4 IU/ml after venous occlusion [7.2 IU/ml (interquartile range 0.8–17.4); P = 0.018]. Endothelial function was impaired in GHD, as quantified by percent flow-mediated vasodilation over 120 sec [area under the curve 3.8 (interquartile range −2.4 to 7.9) vs. 12.8 (interquartile range 2.1–19.4); P = 0.043].

Conclusions: Adults with GHD demonstrate alterations in plasma fibrinolytic balance, including elevated levels of PAI-1 antigen with decreased tPA activity. These changes may contribute to the increased cardiovascular morbidity within this population.
RhoA/Rho Kinase Blocks Muscle Differentiation via Serine Phosphorylation of Insulin Receptor Substrate-1 and -2
Authors: Lim Min Jin , Choi Kyu Jin , Ding Yan , Kim Jin Hwan , Kim Bum Shik , Kim Yun Hong , Lee Jinhwa , Choe Wonchae , Kang Insug , Ha Joohun , Yoon Kyung-Sik , Kim Sung Soo
Published: June 2007

Although the RhoA/Rho kinase (RhoA/ROK) pathway has been extensively investigated, its roles and downstream signaling pathways are still not well understood in myogenic processes. Therefore, we examined the effects of RhoA/ROK on myogenic processes and their signaling molecules using H9c2 and C2C12 cells. Increases in RhoA/ROK activities and serine phosphorylation levels of insulin receptor substrate (IRS)-1 (Ser307 and Ser636/639) and IRS-2 were found in proliferating myoblasts, whereas IRS-1/2 tyrosine phosphorylation and phosphatidylinositol (PI) 3-kinase activity increased during the differentiation process. ROK strongly bound to IRS-1/2 in proliferation medium but dissociated from them in differentiation medium (DM). ROK inactivation by a ROK inhibitor, Y27632, or a dominant-negative ROK, decreased IRS-1/2 serine phosphorylation with increases in IRS-1/2 tyrosine phosphorylation and PI 3-kinase activity, which led to muscle differentiation even in proliferation medium. Inhibition of ROK also enhanced differentiation in DM. ROK activation by a constitutive active ROK blocked muscle differentiation with the increased IRS-1/2 serine phosphorylation, followed by decreases in IRS-1/2 tyrosine phosphorylation and PI 3-kinase activity in DM. Interestingly, fibroblast growth factor-2 added to DM also blocked muscle differentiation through RhoA/ROK activation. Fibroblast growth factor-2 blockage of muscle differentiation was reversed by Y27632. Collectively, these results suggest that the RhoA/ROK pathway blocks muscle differentiation by phosphorylating IRS proteins at serine residues, resulting in the decreased IRS-1/2 tyrosine phosphorylation and PI 3-kinase activity. The absence of the inhibitory effects of RhoA/ROK in DM due to low concentrations of myogenic inhibitory growth factors seems to allow IRS-1/2 tyrosine phosphorylation, which stimulates muscle differentiation via transducing normal myogenic signaling.
Burning surfaces evolution in solid propellants: A numerical model
Authors: Szmelter J , Ortiz P
Published: June 2007

A methodology for the solution of the internal physics of solid propellant rocket motors is described. The problem involves the simulation of a burning surface - a dynamically changing interface between the solid propellant and combustion gas phases. Burning surfaces can have complex shapes that change in time according to the solid chemistry and deformation, and according to gas parameters. The key element of the proposed model is the development of a new technique to conform the computational mesh to the interface. The paper documents mesh handling and solution procedures suitable for axisymmetric applications. The approach is to treat the problem in a uniform manner for solid and gas phases as a flow with moving sources. Unstructured, dynamically adjusting meshes are employed in the same way for both phases. This paper presents two specific test cases, with non-deforming solids, for which a comparison with theoretical results is possible.
On calculation of preliminary design parameters for lenticular booms
Authors: Hakkak F , Khoddam S
Published: June 2007

Deployable booms play an important role in holding instruments away from the satellites, and the more rigid they are, the greater the attitude stability of the satellite and instruments will be. Several design concepts for the deployable booms have been proposed and implemented, among which the lenticular boom is one of the most rigid ones. In the present paper, a method for estimation of the design parameters of lenticular booms is proposed. The design parameters investigated in this paper are bending and torsional equivalent moments of area, and elastic energy and maximum stresses developed in the flattened booms. The proposed method has been validated against finite-element solutions and is shown to be sufficiently accurate to be safely used for preliminary design of lenticular booms.
Modelling of a twin rotor system: A particle swarm optimization approach
Authors: Alam M S , Tokhi M O
Published: June 2007

A scaled and simplified version of a practical helicopter, namely the twin rotor multi-input multi-output system (TRMS) is often used as a laboratory platform for control experiments. This system resembles a helicopter in many aspects. Since the TRMS permits both 1 and 2 degrees of freedom (DOF) motions, it can be considered as a static test rig for an air vehicle. This study presents investigations into modelling of the TRMS using particle swarm optimization (PSO). First, 1-DOF models are extracted for both vertical (pitch) and horizontal (yaw) channels independently. Then, a 2-DOF parametric model is developed taking cross-coupling between the channels into consideration. A particle swarm algorithm that uses time-varying inertia weight factor and time-varying acceleration coefficients is considered in this work. The effectiveness of the algorithm in modelling the system is validated and verified in terms of tracking, stability, and ability of derived model in capturing the dynamics of the system. Time domain and frequency domain results of the derived models clearly show the potential of PSO in solving such control problems.
Adaptive non-linear model inversion control of a twin rotor multi-input multi-output system using artificial intelligence
Authors: Rahideh A , Shaheed H M , Bajodah A H
Published: June 2007

This paper investigates the development of an adaptive dynamic non-linear model inversion control law for a twin rotor multi-input multi-output system (TRMS) utilizing artificial neural networks and genetic algorithms. The TRMS is an aerodynamic test rig representing the control challenges of modern air vehicles. A highly non-linear one degree of freedom mathematical model of the TRMS is considered in this study and a non-linear inverse model is developed for the pitch channel. In the absence of model inversion errors, a genetic algorithm-tuned proportional-derivative (PD) controller is used to enhance the tracking characteristics of the system. An adaptive neural network element is integrated, thereafter, with the feedback control system to compensate for model inversion errors. In order to show the effectiveness of the proposed method in the simulation environment an inversion error has deliberately been provided as an uncertainty in the real situation. Square and sinusoidal reference command signals are used to test the control system performance, and it is noted that an excellent tracking response is exhibited in the presence of inversion errors caused by model uncertainty.
Experimental techniques for measurements of vorticity and strain rates in compressible turbulence interactions with shock or expansion waves
Authors: Xanthos S , Gong M , Agui J , Andreopoulos Y
Published: June 2007

The present work describes The development and validation of a custom-made hot-wire vorticity probe capable of measuring the time-dependent highly fluctuating three-dimensional velocity and vorticity vectors, and associated total temperature, in non-isothermal and inhomogeneous flows with reasonable spatial and temporal resolution. The probe has been used in interactions of compressible homogeneous and isotropic turbulence with shock waves, interactions of vortices with shock waves, and interactions of homogeneous and isotropic turbulence with expansion waves. These flows have been configured in a large-scale shock tube facility. The availability of these data allowed the computations of several terms appearing in the transport equation of vorticity, the full dissipation rate of the kinetic energy term, and full rate-of-strain tensor. An analysis of the uncertainties involved in these measurements suggests that they depend on the particular flow under consideration.
Analytical solution for venting from a time-dependent cavity volume
Authors: Mehta R C
Published: June 2007

The jet flow at the orifice produced by a cavity-pumping device is studied in the present paper. Internal instantaneous pressure is obtained using analytical solution based on assumptions of isothermal condition and incompressible flow. An example of a venting of a cylindrical cavity with initial volume 1.59 × 10−5 m3 and orifice area 1.96 × 10−5 m2 is considered to determine the differential pressure across the orifice under the sinusoidal variation of the cavity volume. Variation of maximum pressure jump across the orifice as function of angular frequency is obtained for a given cavity volume ratio. The analytical solution of time-dependent volume of incompressible flow retains all the geometrical parameters of the synthetic jet actuator, therefore, can be employed to validate numerical solution of compressible flow under the isothermal condition.
Development of an indicial function approach for the two-dimensional incompressible/compressible aerodynamic load modelling
Authors: Marzocca P , Librescu L , Kim D-H , Lee I , Schober S
Published: June 2007

By using a combined analytical-computational methodology, a unified modelling of aerodynamic indicial functions covering the incompressible, subsonic compressible, transonic, and supersonic flight speed regimes is presented. The procedure is carried out in conjunction with a computational fluid dynamic analysis. For a plunging-pitching airfoil, selected unsteady aerodynamic load expressions have been supplied, and appropriate procedures enabling one to obtain these loads via the indicial function approach have been presented. While a single indicial function is needed to describe the aerodynamic loads in the incompressible flight speed regime, for cases where the compressibility effects play a dominant role, four indicial functions are needed. Having in view the usefulness of indicial functions towards determination of unsteady aerodynamics loads in both time and frequency domains, and implicitly for aeroelastic response and flutter predictions, the advantages of their implementation and use appear evident. Comparisons and validations of the aerodynamic model against numerical, analytical, and experimental results are presented, and pertinent conclusions are drawn.
Wing flutter suppression enhancement using a well-suited active control model
Authors: Marretta R M A , Marino F
Published: June 2007

State-space theory is employed here to model a new active wing flutter suppression control. In this paper, the design of a flutter suppression control law, for the NASA Benchmark Active Control Technology wing, is proposed through a single input-single output controller and unsteady aerodynamics is modelled using the Theodorsen's theory. Wing dynamic model is obtained by combining the aeroelastic equations of motion with the actuator model presented. Open-loop dynamic behaviour is examined for a single feedback variable that combines pitch and plunge accelerations. Here, a new formulation of control law, based on classical control techniques and featuring two feedback closed-loops, is successfully employed to reach superior stability robustness with respect to other control laws designed with classical flutter suppression schemes having only one feedback closed-loop. The process allows the stability of the aeroelastic system for flight speeds that exceed the open-loop flutter velocity.
A Review of Richard Layard, Stephen Nickell, and Richard Jackman's Unemployment: Macroeconomic Performance and the Labour Market
Authors: Blanchard Olivier
Published: June 2007

Unemployment: Macroeconomic Performance and the Labour Market by Richard Layard, Stephen Nickell, and Richard Jackman (Oxford University Press 2005) is the second edition of a book first published in 1991. The second edition is identical to the first except for a long introduction, which reviews the conclusions of the first edition in the light of the following fifteen years. I basically agree with the authors that the book's framework and conclusions have withstood the test of time very well. I then assess progress since 1991 and point to a number of directions in which progress needs to be achieved.
Optimal Executive Compensation versus Managerial Power: A Review of Lucian Bebchuk and Jesse Fried's Pay without Performance: The Unfulfilled Promise of Executive Compensation
Authors: Weisbach Michael S
Published: June 2007

This essay reviews Lucian A. Bebchuk and Jesse M. Fried's Pay without Performance: The Unfulfilled Promise of Executive Compensation. Bebchuk and Fried criticize the standard view of executive compensation, in which executives negotiate contracts with shareholders that provide incentives that motivate them to maximize the shareholders' welfare. In contrast, Bebchuk and Fried argue that executive compensation is more consistent with executives who control their own boards and who maximize their own compensation subject to an “outrage constraint.” They provide a host of evidence consistent with this alternative viewpoint. The book can be evaluated from both positive and normative perspectives. From a positive perspective, much of the evidence they present, especially about the camouflage and risk-taking aspects of executive compensation systems, is fairly persuasive. However, from a normative perspective, the book conveys the idea that policy changes can dramatically improve executive compensation systems and consequently overall corporate performance. It is unclear to me how effective potential reforms designed to achieve such changes are likely to be in practice.
What Do Laboratory Experiments Measuring Social Preferences Reveal About the Real World?
Authors: Levitt Steven D , List John A
Published: June 2007

A critical question facing experimental economists is whether behavior inside the laboratory is a good indicator of behavior outside the laboratory. To address that question, we build a model in which the choices that individuals make depend not just on financial implications, but also on the nature and extent of scrutiny by others, the particular context in which a decision is embedded, and the manner in which participants and tasks are selected. We present empirical evidence demonstrating the importance of these various factors. To the extent that lab and naturally occurring environments systematically differ on any of these dimensions, the results obtained inside and outside the lab need not correspond. Focusing on experiments designed to measure social preferences, we discuss the extent to which the existing laboratory results generalize to naturally-occurring markets. We summarize cases where the lab may understate the importance of social preferences as well as instances in which the lab might exaggerate their importance. We conclude by emphasizing the importance of interpreting laboratory and field data through the lens of theory.
Hedge Funds: Past, Present, and Future
Authors: Stulz René M
Published: June 2007

Assets managed by hedge funds have grown faster over the last ten years than assets managed by mutual funds. Hedge funds and mutual funds perform the same economic function, but hedge funds are largely unregulated while mutual funds are tightly regulated. This paper compares the organization, performance, and risks of hedge funds and mutual funds. It then examines whether one can expect increasing convergence between these two investment vehicles and concludes that the performance gap between hedge funds and mutual funds will narrow, that regulatory developments will limit the flexibility of hedge funds, and that hedge funds will become more institutionalized.
How Wages Change: Micro Evidence from the International Wage Flexibility Project
Authors: Dickens William T , Goette Lorenz , Groshen Erica L , Holden Steinar , Messina Julian , Schweitzer Mark E , Turunen Jarkko , Ward Melanie E
Published: June 2007

Workers' wages are not set in a spot market. Instead, the wages of most workers—at least those who do not switch jobs—typically change only annually and are mediated by a complex set of institutions and factors such as contracts, unions, standards of fairness, minimum wage policy, transfers of risk, and incomplete information. The goal of the International Wage Flexibility Project (IWFP)—a consortium of over 40 researchers with access to individual workers' earnings data for 16 countries—is to provide new microeconomic evidence on how wages change for continuing workers. We investigate the extent of wage flexibility, with a particular focus on the extent of downward wage rigidity; and explore how measures of wage flexibility are affected by the wage-setting regimes that typically vary by country.
The American Family and Family Economics
Authors: Lundberg Shelly , Pollak Robert A
Published: June 2007

Gary Becker's path-breaking Treatise on the Family (1981) subjected individuals' decisions about sex, marriage, childbearing, and childrearing to rational choice analysis. The American family has changed radically in recent decades; we survey these changes as well as the ongoing effort to understand partnering, parenting, and care of the elderly as results of maximizing choices made by individuals. First, we describe the recent changes in the American family: the separation of sex, marriage, and childbearing; fewer children and smaller households; converging work and education patterns for men and women; class divergence in partnering and parenting strategies; and the replacement of family functions and home production by government programs and market transactions. Second, we examine recent work in family economics that attempts to explain these changes. Third, we point out some challenging areas for further analysis and highlight issues of commitment in two primary family relationships: those between men and women, and those between parents and children. Finally, we consider the effectiveness of policies to target benefits to certain family members (for instance, children) or to promote marriage and fertility.
Guess Who's Been Coming to Dinner? Trends in Interracial Marriage over the 20th Century
Authors: Fryer Roland G
Published: June 2007

This paper studies marriages across black, white, and Asian racial lines. Marrying across racial lines is a rare event, even today. Interracial marriages account for approximately 1 percent of white marriages, 5 percent of black marriages, and 14 percent of Asian marriages. Following a brief history of the regulation of race and romance in America, I analyze interracial marriage using census data from 1880–2000, uncovering a rich set of cross-section and time-series patterns. I investigate the extent to which three different theories of interracial marriage can account for the patterns discovered. After also testing a social exchange theory and a search model, I find the data are most consistent with a Becker-style marriage market model in which objective criteria of a potential spouse, their race, and the social price of intermarriage are central.
Biological Basics and the Economics of the Family
Authors: Cox Donald
Published: June 2007

Many economic models of the family are based on a generic “person 1—person 2” household or “parent—child” family, rather than their anatomically correct counterparts: sons and daughters, fathers and mothers, and grandfathers and grandmothers. These economic models can offer powerful insights into family behavior, but also can leave certain patterns unexplained and neglect potentially important crosscurrents. “Bio-founded” approaches explicitly consider sex differences in reproductive capabilities and constraints, and can illuminate differences in the goals and interests of men versus women regarding preferences for a mate, decisions to marry or to terminate a marriage, how much to invest in a relationship, how much to invest in children, and how much to value the quality relative to the quantity of children Melding biological insights with family economics can cast new light on existing knowledge and open up novel paths for research. This paper generates biologically based hypotheses about family behavior by using Hamilton's rule, which holds that the costs and benefits of altruistic acts are weighted by the closeness of the genetic relationship, and by noting various fundamentals of human reproductive biology (for instance, a father might be uncertain of his genetic relationship to offspring, but a mother almost never is). This strategy generates a unified approach for modeling diverse aspects of family behavior. My discussion of biological fundamentals will include applications, empirical illustrations, and suggestions for how to merge these basics with current economic thinking.
Community Identification of Natural Health Product–Drug Interactions
Authors: Charrois Theresa L , Hill Richard L , Vu Duc , Foster Brian C , Boon Heather S , Cramer Kristie , Vohra Sunita
Published: June 2007

Background:

The majority of Canadians use natural health products (NHPs), most of which are purchased in pharmacies. Community pharmacists regularly field inquiries regarding NHPs. As such, pharmacists are ideally placed to answer questions about NHP use and interactions with other medications.

Objective:

To identify community pharmacists’ familiarity with NHPs and NHP-related adverse events (AEs) and their knowledge and ability to counsel on potential and known NHP–drug interactions.

Methods:

Survey questions were derived from a literature review of previous surveys, data collected from Health Canada, and in consultation with clinicians, pharmacists, policy-makers, and researchers. A convenience sample of 321 community pharmacists in Alberta and British Columbia were asked to participate.

Results:

We received responses from 132 pharmacists, resulting in a response rate of 41% (132/321). A total of 19% of the sample had previously reported an adverse event to Health Canada. When asked specifically about NHP–drug interactions/AEs, 47% of pharmacists stated that they had identified a potential interaction; however, only 2 of these reported it to Health Canada. Pharmacists were most familiar (76% of respondents) with the interaction between sertraline and St. John's wort and were least familiar with interactions between NHPs and antiretrovirals.

Conclusions:

This survey provides evidence to suggest that pharmacists encounter reportable NHP–drug interactions, yet rarely choose to report these events. The current lack of available data on NHP AEs makes it difficult to provide patients and healthcare providers with useful strategies for managing AEs and drug interactions. Changes to the current system of monitoring AEs due to NHPs and further education of healthcare professionals regarding NHP—drug interactions is required.
John M. Stewart, 1926–2006
Authors: Mous Maarten
Published: June 2007

John M. Stewart passed away on 22nd May 2006. John Stewart was born on 6th February 1926 in Lossiemouth in Scotland. He was proud of his Scottish identity and the last (and unfinished) article that he worked on was a new explanation of the historical developments in the vowels of Scots using his insights from vowel changes in West African languages.
Relationship of Fish Mesohabitat to Flow in a Sand-Bed Southwestern River
Authors: Kehmeier Jon W. , Valdez Richard A. , Medley C. Nicolas , Myers Orrin B.
Published: June 2007

We quantified the availability and utilization of habitat types by eight small-bodied cyprinid fish species, including the federally threatened Pecos bluntnose shiner Notropis simus pecosensis, in the Pecos River, New Mexico. The Pecos River is a medium-sized, sand-bed river with a highly variable hydrograph and some reaches characterized by historic and recent periods of flow intermittency. Fish habitat was described in four reaches at flows of 0.05–2.29 m3/s by means of a simultaneous, coordinated program of channel topographic surveys, mesohabitat mapping, fish sampling, and measurement of microhabitat and chemical parameters. We determined that fish habitat in this sand-bed river was effectively described at the mesohabitat scale. Furthermore, mesohabitats were visually distinguishable and separable by means of hydraulic and geomorphic parameters and the relationship between flow and depth, velocity, and velocity : depth ratios. The eight cyprinid species in the Pecos River primarily used four mesohabitat types that were consistently available at the full range of flows examined, including perpendicular and parallel plunges, backwaters, and slackwaters. In winter, five species (red shiner Cyprinella lutrensis, plains killifish Fundulus zebrinus, plains minnow Hybognathus placitus, Arkansas River shiner N. girardi, and sand shiner N. stramineus) shifted to backwaters, where water temperatures were relatively warmer than those of the main channel. Runs, flats, and riffles were generally the most available mesohabitat types, but their availability changed with flow; only four species (red shiner, plains killifish, speckled chub Macrhybopsis aestivalis, and sand shiner) selected these types, and they did so infrequently in summer. The Pecos bluntnose shiner was a habitat specialist that selected primarily rare plunge pools at sandbar faces, whereas species such as the red shiner were habitat generalists that used a variety of mesohabitat types. We found that a range of base flows sustained the preferred habitats of the eight cyprinid species and that no single flow maximized this preferred habitat because of a scaling effect of flow on sand bedforms.
Estimating Fishing Mortality, Natural Mortality, and Selectivity Using Recoveries from Tagging Young Fish
Authors: Jiang Honghua , Brownie Cavell , Hightower Joseph E. , Pollock Kenneth H.
Published: June 2007

Current methods for estimation of age- and year-specific instantaneous mortality rates based on multiyear, multiple-age tagging studies assume that it is feasible to tag fish in a wide range of ages. For some species, however, only the youngest one or two age-classes are readily available for tagging. Given the practical advantages of tagging young fish only, an important question is whether such studies would provide the information needed for estimation of age-dependent mortality rates. We investigated three designs: tagging only the youngest available age-class, tagging the two youngest age-classes, and tagging the first five age-classes. We carried out simulation studies to assess estimator performance under these three designs, in each case assuming the same total number of tagged fish. Data were generated assuming fishing mortality rates to be age and year dependent and natural mortality rates to be constant or with limited age dependence. Estimator performance is best when fish are tagged in five age-classes, and tagging fish in the two youngest age-classes shows substantial improvement compared with tagging one age-class only. External information about the tag-reporting rate is necessary to obtain estimators with reasonable properties, especially in the case of models with age-dependent natural mortality. Such information can be obtained from auxiliary studies by means of high-reward tags or planted tags. Collecting recovery information for several additional years after the last release produces small improvements in precision and bias. If tagging fish in multiple age-classes is impractical, reasonable precision can be obtained by tagging one or preferably two age-classes and obtaining supplemental information on the reporting rate. For illustration, estimates of age-dependent fishing and natural mortality rates were obtained from tag returns on Chesapeake Bay striped bass Morone saxatilis tagged at ages 3 and 4 years.
A Technique for Preparing Fin Rays and Spines for Age and Growth Analysis
Authors: Koch Jeff D. , Quist Michael C.
Published: June 2007

Fin rays and spines are becoming more popular for age and growth analysis. A protocol for processing structures is first to mount the structure in epoxy, then to use a low-speed saw or handsaw to section the structure, and finally to estimate age from the resulting section. Unfortunately, scientists are often unaware of efficient techniques for mounting structures for such analyses. We describe a simple technique for mounting fin rays and spines in epoxy in preparation for sectioning. The advantages of this method include minimal preparation time, low cost, and little or no damage to hard structures. We have used this technique extensively to estimate age from the fin rays and spines of shovelnose sturgeon Scaphirhynchus platorynchus, catostomids, cyprinids, and ictalurids; however, this technique is useful for any species for which fin rays or spines are used in age and growth analyses. In addition, the technique is not limited to fin rays and spines; it can also be used to prepare a variety of other structures, such as scutes, otoliths, and brachiostegal rays.
Patterns of Habitat Use among Vegetation‐Dwelling Littoral Fishes in the Atchafalaya River Basin, Louisiana
Authors: Troutman John P. , Rutherford D. Allen , Kelso W. E.
Published: June 2007

Information regarding the relative value of different aquatic macrophytes as fish habitat is lacking for large floodplain river systems, such as the Atchafalaya River basin in south‐central Louisiana. We made seasonal comparisons of fish (total length, <100 mm) density, diversity, and biomass and physicochemistry among submersed hydrilla Hydrilla verticillata, emergent bulltongue Sagittaria lancifolia, and floating water hyacinth Eichhornia crassipes. In addition, we examined the influence of habitat structure and physicochemistry on fish assemblage composition and density. Although there were no seasonal differences in fish biomass among plant types, hydrilla consistently supported the greatest fish density and diversity across seasons. While hydrilla and water hyacinth fish density changed little among seasons, density in bulltongue was higher during low water. Of the 12 most common fish species, the pirate perch Aphredoderus sayanus and yellow bullhead Ameiurus natalis showed no consistent pattern of habitat use. However, the densities of golden topminnow Fundulus chrysotus, bluegill Lepomis macrochirus, warmouth L. gulosus, redear sunfish L. microlophus, and pugnose minnow Opsopoeodus emiliae were highest in hydrilla, whereas the density of bantam sunfish L. symmetricus was highest in water hyacinth. A seasonally variable pattern was found for western mosquitofish Gambusia affinis, redspotted sunfish L. miniatus, sailfin molly Poecilia latipinna (higher in bulltongue), and least killifish Heterandria formosa (lower in water hyacinth). Overall, littoral fish distributions reflected responses to several spatially and temporally variable environmental factors (e.g., water quality, plant complexity, and seasonal depth changes). We suggest that the consistently high fish density and diversity in hydrilla across seasons were related to an optimization of favorable water quality (particularly dissolved oxygen [DO]), architectural complexity, and biovolume. However, during low water, as hydrilla and water hyacinth canopies became very dense and water hyacinth DO levels remained low, bulltongue was more heavily used by several species, presumably because of a more favorable combination of DO, complexity, and particularly depth.
The metabolic syndrome: setting the scene. The cons
Authors: Sattar Naveed
Published: June 2007

Conclusion: Metabolic syndrome is conceptually useful. It has encouraged thought about the pathology of diabetes and cardiovascular disease, has facilitated research and has brought together cardiologists and diabetologists. But the criteria are neither needed nor additive for CVD risk assessment or diabetes screening or prediction. Neither are they needed to determine treatment benefit.

Better options would be to measure and target established risk factors such as lipids, smoking and elevated blood pressure. We should also be thinking about obesity and its prevention, and to do this we need changes in food, activity and fiscal environments.
The Face Symbol: Research Issues and Cartographic Potential
Authors: Nelson Elisabeth S.
Published: June 2007

The face symbol, developed by Herman Chernoff (1973) , is possibly the seminal multivariate point symbol. Cartographically, the symbol has made an appearance several times, but it has often been criticized because designers tend to ignore two key symbol parameters: feature salience and natural correspondence. Feature salience is the concept of perceptually ordering facial features from those that produce the most noticeable changes to those that produce the least noticeable changes. Natural correspondence refers to designing face symbols so that the overall attitudinal labels of the symbols correspond to the overall physical meaning of the mapped data. It is argued here that feature salience and natural correspondence may be treated as special cases of visual attention in relation to symbol design. From this perspective, these symbols deserve a new look cartographically. This research reports on symbol variations, explores feature salience and natural correspondence, addresses user environments and tasks, and speculates on future experimental designs that may lead to more effective map use of this symbol.