bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of conjugated linoleic acid isomers on fatty acid profiles of liver and adipose tissues and their conversion to isomers of 16∶2 and 18∶3 conjugated fatty acids in rats
Authors: Sébédio J. ‐L. , Angioni E. , Chardigny J. M. , Grégoire S. , Juanéda P. , Berdeaux O.
Published: November 2006

Conjugated linoleic acid (CLA) is a collective term that describes different isomers of linoleic acid with conjugated double bonds. Although the main dietary isomer is 9cis,11trans‐18∶2, which is present in dairy products and ruminant fat, the biological effects of CLA generally have been studied using mixtures in which the 9cis,11trans‐ and the 10trans,12cis‐18∶2 were present at similar levels. In the present work, we have studied the impact of each isomer (9cis,11trans‐ and 10trans,12cis‐18∶2) given separately in the diet of rats for 6 wk. The 10trans,12cis‐18∶2 decreased the triacylglycerol content of the liver (−32%) and increased the 18∶0 content at the expense of 18∶1n−9, suggesting an alteration of the Δ9 desaturase activity, as was already demonstrated in vitro. This was not observed when the 9cis,11trans‐18∶2 was given in the diet. Moreover, the 10trans,12cis‐18∶2 induced an increase in the C22 polyunsaturated fatty acids in the liver lipids. The 10trans,12cis‐18∶2 was mainly metabolized into conjugated 16∶2 and 18∶3, which have been identified. The 9cis,11trans isomer was preferentially metabolized into a conjugated 20∶3 isomer. Thus, the 9cis,11trans‐ and the 10trans,12cis‐CLA isomers are metabolized differently and have distinct effects on the metabolism of polyunsaturated fatty acids in rat liver while altering liver triglyceride levels differentially.
What is the role of α‐linolenic acid for mammals?
Authors: Sinclair Andrew J. , Attar‐Bashi Nadia M. , Li Duo
Published: November 2006

This review examines the data pertaining to an important and often underrated EFA, α‐linolenic acid (ALA). It examines its sources, metabolism, and biological effects in various population studies, in vitro, animal, and human intervention studies. The main role of ALA was assumed to be as a precursor to the longer‐chain n‐3 PUFA, EPA and DHA, and particularly for supplying DHA for neural tissue. This paper reveals that the major metabolic route of ALA metabolism is β‐oxidation. Furthermore, ALA accumulates in specific sites in the body of mammals (carcass, adipose, and skin), and only a small proportion of the fed ALA is converted to DHA. There is some evidence that ALA may be involved with skin and fur function. There is continuing debate regarding whether ALA has actions of its own in relation to the cardiovascular system and neural function. Cardiovascular disease and cancer are two of the major burdens of disease in the 21st century, and emerging evidence suggests that diets containing ALA are associated with reductions in total deaths and sudden cardiac death. There may be aspects of the action and, more importantly, the metabolism of ALA that need to be elucidated, and these will help us understand the biological effects of this compound better. Additionally, we must not forget that ALA is part of the whole diet and should be seen in this context, not in isolation.
The effects of vitamin E and selenium intake on oxidative stress and plasma lipids in hamsters fed fish oil
Authors: Poirier Johanne , Cockell Kevin , Hidiroglou Nick , Madere Rene , Trick Keith , Kubow Stan
Published: November 2006

The aim of the present work was to test the effects of large‐dose supplementation of vitamin E (Vit E) and selenium (Se), either singly or in combination, on fish oil (FO)‐induced tissue lipid peroxidation and hyperlipidemia. The supplementation of Se has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however, the effects of Se supplementation, either alone or in combination with supplemental Vit E, on FO‐induced oxidative stress and hyperlipidemia have not been studied. Male Syrian hamsters received FO‐based diets that contained 14.3 wt% fat and 0.46 wt% cholesterol supplemented with Vit E (129 IU d‐α‐tocopheryl acetate/kg diet) and/or Se (3.4 ppm as sodium selenate) or that contained basal requirements of both nutrients. The cardiac tissue of hamsters fed supplemental Se showed increased concentrations of lipid hydroperoxides (LPO) but decreased oxidized glutathione (GSSG) concentrations. The higher concentrations of LPO in the hearts of Se‐supplemented hamsters were not lowered with concurrent Vit E supplementation. In the liver, Se supplementation was associated with higher Se‐dependent glutathione peroxidase activity and an increase in the GSH/GSSG ratio, whereas a lower hepatic non‐Se‐dependent glutathione peroxidase activity was seen with Vit E supplementation. Supplemental intake of Se was associated with lower plasma concentrations of total cholesterol and low density lipoprotein cholesterol plus very low density lipoprotein cholesterol. In view of the pro‐oxidative effects of Se supplementation on cardiac tissue, a cautionary approach needs to be taken regarding the plasma lipid‐lowering properties of supplemental Se.
Vitamin E supplementation increases circulating vitamin E metabolites tenfold in end‐stage renal disease patients
Authors: Smith Kylie Sherée , Lee Chia‐Lin , Ridlington James W. , Leonard Scott W. , Devaraj Sridevi , Traber Maret G.
Published: November 2006

Vitamin E supplementation could elevate circulating vitamin E metabolites while modulating oxidative and inflammatory status in end‐stage renal failure patients undergoing hemodialysis. Plasma concentrations of carboxyethyl‐hydroxychromanols (α‐and γ‐CEHC), ascorbic acid, α‐and γ‐tocopherols, E2‐isoprostanes, and inflammatory biomarkers [tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), ferritin, and C‐reactive protein (CRP)] were measured in blood samples obtained from patients (n=11) before and after dialysis on two occasions prior to, and at 1 and 2 mon of daily vitamin E supplementation (400 IU RRR‐α‐tocopherol). Supplementation nearly doubled plasma α‐tocopherol concentrations (from 18±0.5 to 31±1.7 μM, P<0.0001), whereas γ‐tocopherol concentrations decreased (from 2.8±0.3 to 1.7±0.2 μM, P=0.001). Serum α‐CEHC increased 10‐fold from 68±3 to 771±175 nM (P<0.0001), and γ‐CEHC increased from 837±164 to 1136±230 nM (P=0.008). Vitamin E supplementation also increased postdialysis hematocrits from 38±1% to 41±1% (P<0.001). Dietary antioxidant intakes (vitamins E and C) were low in most subjects; plasma ascorbic acid levels (88±27 μM) decreased significantly with dialysis (33±11 μM, P=0.01). Plasma Il‐6, CRP, TNF‐α, and free F2‐isoprostane concentrations were elevated throughout the study. There is a complex relationship between chronic inflammation and oxidative stress that is not mitigated by short‐term vitamin E supplementation. Importantly, serum vitamin E metabolite concentrations that increased 10‐fold within 30 d of supplementation did not increase further, suggesting routes other than urine for removal of metabolites.
Lipid synthesis and acyl‐CoA synthetase in developing rice seeds
Authors: Ichihara Ken'ichi , Kobayashi Noriaki , Saito Kazumi
Published: November 2006

Developing rice seeds rapidly accumulated storage lipids between 5 and 12 d after flowering. The contents of palmitic, oleic, and linoleic acids increased throughout seed development, while the α‐linolenic acid content remained low. The activity of acyl‐CoA synthetase varied coincidentally during the period of lipid accumulation, and rice seeds had a sufficient capacity to supply acyl‐CoA substrates for TAG synthesis. Acyl‐CoA synthetase showed a broad specificity for native FA of rice seeds except for stearic acid, and π electrons of a Δ9–Δ11 double bond in the C16−C18 acyl chains were required for its maximal activity.
Astonishing diversity of natural surfactants: 3. Carotenoid glycosides and isoprenoid glycolipids
Authors: Dembitsky Valery M.
Published: November 2006

Carotenoid glycosides and isoprenoid glycolipids are of great interest, especially for the medicinal, pharmaceutical, food, cosmetic, flavor, and fragrance industries. These biologically active natural surfactants have good prospects for the future chemical preparation of compounds useful as antimicrobial, antibacterial, and antitumor agents, or in industry. More than 300 unusual natural surfactants are described in this review article, including their chemical structures and biological activities.
Effects of stearic acid on plasma lipid and lipoproteins in humans
Authors: Mensink Ronald P.
Published: November 2006

More than 40 years ago, saturated FA with 12, 14, and 16 carbon atoms (lauric acid, myristic acid, and palmitic acid) were demonstrated to be “hypercholesterolemic saturated FA.” It was further concluded that the serum total cholesterol level would hardly be changed by isocaloric replacement of stearic acid (18∶0) by oleic acid (cis‐18∶1n−9) or carbohydrates. These earlier studies did not address the effects of the various FA on the serum lipoprotein profile. Later studies found that the hypercholesterolemic saturated FA increase serum total cholesterol levels by raising concentrations of both the atherogenic LDL and the antiatherogenic HDL. Consequently, the ratio of total to HDL cholesterol will hardly change when carbohydrates replace these saturated FA. Compared with other saturated FA, stearic acid lowers LDL cholesterol. Studies on the effects on HDL cholesterol are less conclusive. In some, the effects on HDL cholesterol were comparable to those of palmitic acid, oleic acid, and linoleic acid, whereas in others a decrease was observed. This may suggest that in this respect the source of stearic acid is of importance, which needs however further study. From all these studies, however, it can be concluded that stearic acid may decrease the ratio of total to HDL cholesterol slightly when compared with palmitic or myristic acid. Without doubt, the effects of stearic acid are more favorable than those of trans monounsaturated FA.
Mitochondrial cholesterol transport: A possible target in the management of hyperlipidemia
Authors: Hall E. A. , Ren S. , Hylemon P. B. , Redford K. , del Castillo A. , Gil G. , Pandak W. M.
Published: November 2006

Sterol 27‐hydroxylase (CYP27A1) may defend cells against accumulation of excess cholesterol, making this enzyme a possible target in the management of hyperlipidemia. The study objective was to analyze cholesterol homeostatic responses to increases in CYP27A1 activity in HepG2 cells and primary human hepatocytes. Increasing CYP27A1 activity by increasing enzyme expression led to significant increases in bile acid synthesis with compensatory increases in HMG‐CoA reductase (HMGR) activity/protein, LDL receptor (LDLR) mRNA, and LDLR‐mediated cholesterol uptake. Under these conditions, only a small increase in cellular 27‐hydroxycholesterol (27OH‐Chol) concentration was observed. No changes were detected in mature sterol regulatory element‐binding proteins (SREBP) 1 or 2. Increasing CYP27A1 activity by increasing mitochondrial cholesterol transport (i.e., substrate availability) led to greater increases in bile acid synthesis with significant increases in cellular 27OH‐Chol concentration. Mature SREBP 2 protein decreased significantly with compensatory decreases in HMGR protein. No change was detected in mature SREBP 1 protein. Despite increasing 27OH‐Chol and lowering SREBP 2 protein concentrations, LDLR mRNA increased significantly, suggesting alternative mechanisms of LDLR transcriptional regulation. These findings suggest that regulation of liver mitochondrial cholesterol transport represents a potential therapeutic strategy in the treatment of hyperlipidemia and atherosclerosis.
Lipoprotein‐apolipoprotein changes in renal transplant recipients
Authors: Cassader Maurizio , Ruiu Gianluca , Gambino Roberto , Alemanno Natalina , Triolo Giorgio , Veglia Fabrizio , Pagano Gianfranco
Published: November 2006

Recent studies have demonstrated that the incidence of cardiovascular events occurring with renal transplantation is higher than that in the general population. Renal transplantation modifies the characteristic dyslipidemia of chronic renal failure. In this study the change in lipoprotein and lipid values of 103 transplant recipients after transplantation was investigated. The aim of our work was to examine the short‐term and long‐term variations in lipid metabolism. The major lipoprotein fractions (VLDL, LDL, HDL) were separated by preparative ultracentrifugation, and TG and cholesterol concentrations were determined in plasma and lipoprotein fractions. Whole plasma apolipoproteins were determined by a rate immunonephelometric technique. In the pretransplant period the patients displayed the typical picture of uremics. After transplantation the most evident alterations in the lipoprotein profile occurred in our case series after 3 mon. The major finding was a 35% reduction in plasma TG. The modifications in the TG‐rich lipoproteins of our transplant recipients persisted throughout the observation period. In the initial 3‐mon period, total cholesterol remained steady, whereas LDL‐cholesterol and total apolipoprotein B showed a significant increase. No significant changes were found in total and transported TG and cholesterol between the 3‐mon and the 6‐yr values. The substantial stability of cholesterol levels after transplantation and in subsequent reports, as well as a higher incidence of cardiovascular complications, may suggest that the mechanisms responsible for vessel damage must be sought mainly in the structural and physicochemical alterations of the individual lipoprotein fractions or in other risk factors.
Associations between apolipoprotein E genotype and circulating F2‐isoprostane levels in humans
Authors: Dietrich Marion , Hu Youqing , Block Gladys , Olano Estibaliz , Packer Lester , Morrow Jason D. , Hudes Mark , Abdukeyum Gulbahar , Rimbach Gerald , Minihane Anne M.
Published: November 2006

Apolipoprotein E (apoE), an important determinant of plasma lipoprotein metabolism, has three common alleles (ε2, ε3, and ε4). Population studies have shown that the risk of diseases characterized by oxidative damage, such as coronary heart disease and Alzheimer's disease, is significantly higher in ɛ4 carriers. We evaluated the association between apoE genotypes and plasma F2‐isoprostane levels, an index of lipid peroxidation, in humans. Two hundred seventy‐four healthy subjects (104 males, 170 females; 46.9±13.0 yr; 200 whites, 74 blacks; 81 nonsmokers, 64 passive smokers, and 129 active smokers) recruited for a randomized clinical antioxidant intervention trial were included in this analysis. ApoE genotype was determined by PCR and restriction enzyme digestion. Free plasma F2‐isoprostane was measured by GC‐MS. Genotype groups were compared using multiple regression analysis with adjustment for sex, age, race, smoking status, body mass index, plasma ascorbic acid, and β‐carotene. Subjects with ε3/ε4 and ε4/ε4 genotype (ε4‐carriers) and with ε2/ε3 and ε3/ε3 (non‐ε4‐carriers) were pooled for analysis. In subjects with high cholesterol levels (total cholesterol above 200 mg/dl), plasma F2‐isoprostane levels were 29% higher in ε4 carriers than in non‐ε4‐carriers (P=0.0056). High‐cholesterol subjects that are ε4 carriers have significantly higher levels of lipid peroxidation as assessed by circulating F2‐isoprostane levels.
The impact of age, body mass index, and fish intake on the EPA and DHA content of human erythrocytes
Authors: Sands Scott A. , Reid Kimberly J. , Windsor Sheryl L. , Harris William S.
Published: November 2006

n−3 FA are beneficial for cardiovascular health, reducing platelet aggregation, TG levels, and the risk of sudden death from myocardial infarction. The percentage of EPA + DHA in red blood cells (RBC), also known as the Omega‐3 Index, has recently been proposed as a risk marker for death from coronary heart disease (CHD). The purpose of this study was to begin to explore the factors that can influence RBC EPA + DHA. We collected information on the number of servings of tuna or nonfried fish consumed per month, as well as on age, gender, ethnicity, smoking status, the presence of diabetes, and body mass index (BMI) in 163 adults in Kansas City who were not taking fish oil supplements. The average RBC EPA + DHA in this population was 4.9±2.1%. On a multivariate analysis, four factors significantly and independently influenced the Omega‐3 Index: fish servings, age, BMI, and diabetes. The Index increased by 0.24 units with each additional monthly serving of tuna or nonfried fish (P<0.0001), and by 0.5 units for each additional decade in age (P<0.0001). The Index was 1.13% units lower in subjects with diabetes (P=0.015) and decreased by 0.3% units with each 3‐unit increase in BMI (P=0.001). Gender or smoking status had no effect, and the univariate relationship with ethnicity vanished after controlling for deathfrom CHD, further studies are warranted to delineate the nondietary factors that influence RBC EPA + DHA content.
A video method for empirically studying wait‐perception bias
Authors: Seawright Kristie K. , Sampson Scott E.
Published: November 2006

Customer queues resemble inventories of goods in that they both incur costs of waiting. However, the immediate costs of customer queues are primarily psychological, with subsequent costs being customer dissatisfaction and reduced future sales. A fundamental element of psychological waiting costs is wait‐perception bias, which is the propensity to overestimate (or underestimate) the passage of time spent waiting. In 1985, Maister proposed a number of principles that affect wait‐perception bias [Maister, D., 1985. The psychology of waiting lines. In: Czepiel, J., Solomon, M., Surprenant, C. (Eds.), The Service Encounter. Lexington Books, Lexington, MA, pp. 113–123]. Maister's principles have been frequently quoted in operations management literature, but they have rarely been put to empirical test. One challenge in trying to test these principles is that traditional empirical methods can make it very difficult to accurately represent specific waiting conditions while controlling for confounding factors.

This article describes a video‐based data collection methodology for studying wait‐perception bias. We specifically look at Maister's principle about the impact of wait explanation on wait‐perception bias. Results show that there is a significant difference in wait‐perception bias due to the presence or absence of an explanation, but that whether the explanation focuses on customer cause or server cause makes little difference. The findings provide needed empirical support for one of Maister's principles, with additional contribution being the development of a video‐based research methodology that is able to enrich queuing research by enabling the study of wait‐perception bias.
Effect of Surgical Hand Scrub Time on Subsequent Bacterial Growth
Authors: Wheelock Sean McKay , Lookinland Sandra
Published: November 2006

In this experimental study, the researchers evaluated the effect of surgical hand scrub time on subsequent bacterial growth and assessed the effectiveness of the glove juice technique in a clinical setting. In a randomized crossover design, 25 perioperative staff members scrubbed for two or three minutes in the first trial and vice versa in the second trial, after which they wore sterile surgical gloves for one hour under clinical conditions. The researchers then sampled the subjects' nondominant hands for bacterial growth, cultured aliquots from the sampling solution, and counted microorganisms. Scrubbing for three minutes produced lower mean log bacterial counts than scrubbing for two minutes. Although the mean bacterial count differed significantly (P =.02) between the two‐minute and three‐minute surgical hand scrub times, it fell below 0.5 log, which is the threshold for practical and clinical significance. This finding suggests that a two‐minute surgical hand scrub is clinically as effective as a three‐minute surgical hand scrub. The glove juice technique demonstrated sensitivity and reliability in enumerating bacteria on the hands of perioperative staff members in a clinical setting. AORN J 65 (June 1997) 1087‐1098.
THE EFFECT OF HUSBANDS’ FERTILITY PREFERENCES ON COUPLES’ REPRODUCTIVE BEHAVIOUR IN RURAL BANGLADESH
Authors: HOSSAIN MIAN B. , PHILLIPS JAMES F. , MOZUMDER A. B. M. KHORSHED A.
Published: November 2006

Bangladesh society is profoundly gender stratified, and yet male roles in reproductive health processes have not been rigorously investigated. This study examines the association between men’s reproductive health knowledge, attitude and behaviour and their wives’ subsequent reproductive behaviour using longitudinal data from the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). A total of 4969 matched husband-and-wife data from a 1998 survey and women’s contraceptive use history data following this survey are used. Results show a significant association between husbands’ fertility preferences and current use of any family planning method. When wives’ background characteristics, and husbands’ background and socioeconomic characteristics are controlled for, the predicted probability of using a method of contraception among non-educated wives whose husbands want more children is 0·49 compared with 0·64 for those whose husbands do not want more children. However, the net effect of husbands’ preference for additional children diminishes as wives’ level of education increases. Among wives who had completed high school, the predicted probability of using a method of contraception is 0·70 for those whose husbands want more children compared with 0·69 for those whose husbands do not want more children.
The onset of chaos in vortex sheet flow
Authors: KRASNY ROBERT , NITSCHE MONIKA
Published: November 2006

Regularized point-vortex simulations are presented for vortex sheet motion in planar
and axisymmetric flow. The sheet forms a vortex pair in the planar case and a vortex
ring in the axisymmetric case. Initially the sheet rolls up into a smooth spiral, but
irregular small-scale features develop later in time: gaps and folds appear in the spiral
core and a thin wake is shed behind the vortex ring. These features are due to the
onset of chaos in the vortex sheet flow. Numerical evidence and qualitative theoretical
arguments are presented to support this conclusion. Past the initial transient the flow
enters a quasi-steady state in which the vortex core undergoes a small-amplitude
oscillation about a steady mean. The oscillation is a time-dependent variation in
the elliptic deformation of the core vorticity contours; it is nearly time-periodic, but
over long times it exhibits period-doubling and transitions between rotation and
nutation. A spectral analysis is performed to determine the fundamental oscillation
frequency and this is used to construct a Poincaré section of the vortex sheet flow.
The resulting section displays the generic features of a chaotic Hamiltonian system,
resonance bands and a heteroclinic tangle, and these features are well-correlated with
the irregular features in the shape of the vortex sheet. The Poincaré section also
has KAM curves bounding regions of integrable dynamics in which the sheet rolls
up smoothly. The chaos seen here is induced by a self-sustained oscillation in the
vortex core rather than external forcing. Several well-known vortex models are cited
to justify and interpret the results.
A lubrication model of coating flows over a
curved substrate in space
Authors: ROY R. VALÉRY , ROBERTS A. J. , SIMPSON M. E.
Published: November 2006

Consider the three-dimensional flow of a viscous Newtonian fluid upon an arbitrarily
curved substrate when the fluid film is thin as occurs in many draining, coating and
biological flows. We drive the lubrication model of the dynamics of the film expressed
in terms of the film thickness. The comprehensive model accurately includes the
effects of the curvature of the substrate, via a physical multiple-scale approach, and
gravity and inertia, via more rigorous centre manifold techniques. This new approach
theoretically supports the use of the model over a wide range of parameters and
provides a sound basis for further development of lubrication models. Numerical
simulations exhibit some generic features of the dynamics of such thin fluid films
on substrates with complex curvature: we here simulate a film thinning at a corner,
the flow around a torus, and draining of a film down a cylinder. The last is more
accurate than other lubrication models. The model derived here describes well thin-film
dynamics over a wide range of parameter regimes.
The motion generated by a rising particle in a
rotating fluid – numerical solutions. Part 2.
The long container case
Authors: MINKOV E. , UNGARISH M. , ISRAELI M.
Published: November 2006

Numerical finite-difference results from the full axisymmetric incompressible
Navier–Stokes equations are presented for the problem of the slow axial motion of a disk
particle in an incompressible, rotating fluid in a long cylindrical container. The
governing parameters are the Ekman number, E = ν*/(Ω*a*2), Rossby number,
Ro = W*/(Ω*a*), and the dimensionless height of the container, 2H (the scaling
length is the radius of the particle, a*; Ω* is the container angular velocity, W* is the
particle axial velocity and ν* the kinematic viscosity). The study concerns the flow field
for small values of E and Ro while HE is of order unity, and hence the appearance of a
free Taylor column (slug) of fluid ‘trapped’ at the particle is expected. The numerical
results are compared with predictions of previous analytical approximate studies.
First, developed (quasi-steady-state) cases are considered. Excellent agreement with
the exact linear (Ro = 0) solution of Ungarish & Vedensky (1995) is obtained when
the computational Ro = 10−4. Next, the time-development for both an impulsive start
and a start under a constant axial force is considered. A novel unexpected behaviour
has been detected: the flow field first attains and maintains for a while the steady-state
values of the unbounded configuration, and only afterwards adjusts to the bounded
container steady state. Finally, the effects of the nonlinear momentum advection
terms are investigated. It is shown that when Ro increases then the dimensionless
drag (scaled by μ*a*W*) decreases, and the Taylor column becomes shorter, this effect
being more pronounced in the rear region (μ* is the dynamic viscosity). The present
results strengthen and extend the validity of the classical drag force predictions
and therefore the issue of the large discrepancy between theory and experiments
(Maxworthy 1970) concerning this force becomes more acute.
Spectral solution of time-dependent shallow
water hydroelasticity
Authors: MEYLAN MICHAEL H.
Published: November 2006

The spectral theory of a thin plate floating on shallow water is derived and used to
solve the time-dependent motion. This theory is based on an energy inner product in
which the evolution operator becomes unitary. Two solution methods are presented.
In the first, the solution is expanded in the eigenfunctions of a self-adjoint operator,
which are the incoming wave solutions for a single frequency. In the second, the
scattering theory of Lax–Phillips is used. The Lax–Phillips scattering solution is
suitable for calculating only the free motion of the plate. However, it determines the
modes of vibration of the plate–water system. These modes, which both oscillate and
decay, are found by a complex search algorithm based contour integration. As well
as an application to modelling floating runways, the spectral theory for a floating
thin plate on shallow water is a solvable model for more complicated hydroelastic
systems.
Towards a unified science of cultural evolution
Authors: Mesoudi Alex , Whiten Andrew , Laland Kevin N.
Published: November 2006

We suggest that human culture exhibits key Darwinian evolutionary properties, and argue that the structure of a science of cultural evolution should share fundamental features with the structure of the science of biological evolution. This latter claim is tested by outlining the methods and approaches employed by the principal subdisciplines of evolutionary biology and assessing whether there is an existing or potential corresponding approach to the study of cultural evolution. Existing approaches within anthropology and archaeology demonstrate a good match with the macroevolutionary methods of systematics, paleobiology, and biogeography, whereas mathematical models derived from population genetics have been successfully developed to study cultural microevolution. Much potential exists for experimental simulations and field studies of cultural microevolution, where there are opportunities to borrow further methods and hypotheses from biology. Potential also exists for the cultural equivalent of molecular genetics in “social cognitive neuroscience,” although many fundamental issues have yet to be resolved. It is argued that studying culture within a unifying evolutionary framework has the potential to integrate a number of separate disciplines within the social sciences.
Culture evolves only if there is cultural inheritance
Authors: Aunger Robert
Published: November 2006

Mesoudi et al. argue that the current inability to identify the means by which cultural traits are acquired does not debilitate their project to draw clear parallels between cultural and biological evolution. However, I suggest that cultural phenomena may be accounted for by biological processes, unless we can identify a cultural “genotype” that carries information from person to person independently of genes.
Genes for susceptibility to mental disorder are not mental disorder: Clarifying the target of evolutionary analysis and the role of the environment
Authors: Allen Nicholas B. , Badcock Paul B. T.
Published: November 2006

In this commentary, we critique the appropriate behavioural features for evolutionary genetic analysis, the role of the environment, and the viability of a general evolutionary genetic model for all common mental disorders. In light of these issues, we suggest that the authors may have prematurely discounted the role of some of the mechanisms they review, particularly balancing selection.
The social environment compresses the diversity of genetic aberrations into the uniformity of schizophrenia manifestations
Authors: Behrendt Ralf-Peter
Published: November 2006

Genetically and neurodevelopmentally, there may be a thousand schizophrenias, yet there would be no schizophrenia at all without active contribution from all of us; none – outside the primitive processes that regulate our relationship with one another. In order to understand the nature of schizophrenia as it unfolds relatively uniformly in the social context, we need to depart from an evolutionarily more feasible understanding of society.
Analogies are powerful and dangerous things
Authors: Mulder Monique Borgerhoff , McElreath Richard , Schroeder Kari Britt
Published: November 2006

The analogy between biological and cultural evolution is not perfect. Yet, as Mesoudi et al. show, many of the vaunted differences between cultural and genetic evolution (for example, an absence of discrete particles of cultural inheritance, and the blurred distinction between cultural replicators and cultural phenotypes) are, on closer inspection, either illusory or peripheral to the validity of the analogy. But what about horizontal transmission? We strongly agree with the authors that the potential for horizontal transmission of cultural traits does not invalidate an evolutionary approach to culture. We suggest, however, that it does require a different evolutionary treatment.
It is not evolutionary models, but models in general that social science needs
Authors: Bridgeman Bruce
Published: November 2006

Mathematical models are potentially as useful for culture as for evolution, but cultural models must have different designs from genetic models. Social sciences must borrow from biology the idea of modeling, rather than the structure of models, because copying the product is fundamentally different from copying the design. Transfer of most cultural information from brains to artificial media increases the differences between cultural and biological information.
Evolutionary social science beyond culture
Authors: Kincaid Harold
Published: November 2006

Mesoudi et al.'s case can be improved by expanding to compelling selectionist explanations elsewhere in the social sciences and by seeing that natural selection is an instance of general selectionist process. Obstacles include the common use of extreme idealizations and optimality evidence, the copresence of nonselectionist social processes, and the fact that selectionist explanations often presuppose other kinds of social explanations.
Heritable mental disorders: You can't choose your relatives, but it is they who may really count
Authors: Klimkeit Ester I. , Bradshaw John L.
Published: November 2006

Keller & Miller (K&M) briefly mention and promptly dismiss the idea that genes for harmful mental disorders may confer certain advantages to affected individuals. However, the authors fail to consider that the same genes (in low doses or reduced penetrance) may be adaptive for relatives, and that this may in part explain why they are retained in the gene pool.
Are common, harmful, heritable mental disorders common relative to other such non-mental disorders, and does their frequency require a special explanation?
Authors: Mayo Oliver , Leach Carolyn
Published: November 2006

Keller & Miller's (K&M's) conclusion appears to be correct; namely, that common, harmful, heritable mental disorders are largely maintained at present frequencies by mutation-selection balance at many different loci. However, their “paradox” is questionable.
Cultural traits and cultural integration
Authors: Lyman R. Lee
Published: November 2006

Modern efforts to model cultural transmission have struggled to identify a unit of cultural transmission and particular transmission processes. Anthropologists of the early twentieth century discussed cultural traits as units of transmission equivalent to recipes (rules and ingredients) and identified integration as a signature process and effect of transmission.
Archaeology and cultural macroevolution
Authors: O'Brien Michael J.
Published: November 2006

Given the numerous parallels between the archaeological and paleontological records, it is not surprising to find a considerable fit between macroevolutionary approaches and methods used in biology – for example, cladistics and clade-diversity measures – and some of those that have long been used in archaeology – for example, seriation. Key, however, is recognizing that this methodological congruence is illusory in terms of how evolution has traditionally been viewed in biology and archaeology.
Darwinian cultural evolution rivals genetic evolution
Authors: Pagel Mark
Published: November 2006

The study of culture from an evolutionary perspective has been slowed by resistance from some quarters of anthropology, a poor appreciation of the fidelity of cultural transmission, and misunderstandings about human intentionality.
A unified science of cultural evolution should incorporate choice
Authors: Sopher Barry
Published: November 2006

Analogies between biological and cultural evolution may be illuminating and suggest methods to pursue in the quest for a unified science of cultural evolution. Significant progress, however, is unlikely to be made by trying to fit cultural evolution neatly into a biological evolution schema. A key element defining and differentiating cultural evolution may be the role of conscious human choices.
Adaptationism and medicalization: The Scylla and Charybdis of Darwinian psychiatry
Authors: Troisi Alfonso
Published: November 2006

The target article shows that the application of the evolutionary theory to psychopathology should not necessarily consist in finding hidden adaptive benefits for each psychiatric syndrome. However, in rejecting lax adaptationism, Darwinian psychiatrists should not forget that the search for adaptive behavioral polymorphisms can be a powerful antidote against the normative attitude of mainstream psychiatry and its growing tendency to medicalize human diversity.
Population genetical musings on suicidal behavior as a common, harmful, heritable mental disorder
Authors: Voracek Martin
Published: November 2006

Suicidal behavior is an interesting blank space in Keller & Miller's (K&M's) population genetical account on explaining the existence and persistence of common, harmful, heritable mental disorders. I argue that suicidal behavior is yet another of these disorders. It may well be consistent with all three evolutionary models considered by K&M.
Generative entrenchment and an evolutionary developmental biology for culture
Authors: Wimsatt William C.
Published: November 2006

Mesoudi et al.'s new synthesis for cultural evolution closely parallels the evolutionary synthesis of Neo-Darwinism. It too draws inspiration from population genetics, recruits other fields, and, unfortunately, also ignores development. Enculturation involves many serially acquired skills and dependencies that allow us to build a rich cumulative culture. The newer synthesis, evolutionary developmental biology, provides a key tool, generative entrenchment, to analyze them.
High mental disorder rates are based on invalid measures: Questions about the claimed ubiquity of mutation-induced dysfunction
Authors: Wakefield Jerome C.
Published: November 2006

Three reservations about Keller & Miller's (K&M's) argument are explored: Serious validity problems afflict epidemiological criteria discriminating disorders from non-disorders, so high rates may be misleading. Normal variation need not be mild disorder, contrary to a possible interpretation of K&M's article. And, rather than mutation-selection balance, true disorders may result from unselected combinations of normal variants over many loci.
Multiple timescales of evolution
Authors: Williams Jonathan
Published: November 2006

Keller & Miller's (K&M's) treatment of disorders usefully avoids diagnostic minutiae; but it needs more real-world constraints. Classifying processes by their evolutionary age helps to clarify both evolution and current function. Evolutionarily old, optimised, normative processes deserve special recognition, because they can be studied in animals and computers, and because they provide the machinery through which disorder-related polymorphisms act.
An evolutionary framework for mental disorders: Integrating adaptationist and evolutionary genetic models
Authors: Keller Matthew C. , Miller Geoffrey
Published: November 2006

This response (a) integrates non-equilibrium evolutionary genetic models, such as coevolutionary arms-races and recent selective sweeps, into a framework for understanding common, harmful, heritable mental disorders; (b) discusses the forms of ancestral neutrality or balancing selection that may explain some portion of mental disorder risk; and (c) emphasizes that normally functioning psychological adaptations work against a backdrop of mutational and environmental noise.
Special Issue: Constraints and design
Authors: O'SULLIVAN BARRY
Published: November 2006

Constraint processing has emerged as an extremely expressive and
powerful paradigm in which to model, solve, and reason about many complex
problems. Over the past four decades advances in both the fundamental
aspects of constraint processing and practical applications of constraints
have contributed to making it one of the most promising of artificial
intelligence technologies.
Partially defined constraints in constraint-based design
Authors: LALLOUET ARNAUD , LEGTCHENKO ANDREÏ
Published: November 2006

In constraint-based design, components are modeled by variables
describing their properties and subject to physical or mechanical
constraints. However, some other constraints are difficult to represent,
like comfort or user satisfaction. Partially defined constraints can be
used to model the incomplete knowledge of a concept or a relation. Instead
of only computing with the known part of the constraint, we propose to
complete its definition by using machine-learning techniques. Because
constraints are actively used during solving for pruning domains, building
a classifier for instances is not enough: we need a solver able to reduce
variable domains. Our technique is composed of two steps: first we learn a
classifier for the constraint's projections and then we transform the
classifier into a propagator. We show that our technique not only has good
learning performances but also yields a very efficient solver for the
learned constraint.
The representation and handling of constraints for the design, analysis, and optimization of high speed machinery
Authors: HICKS B.J. , MEDLAND A.J. , MULLINEUX G.
Published: November 2006

High speed machinery has played and continues to play a vital role in the manufacture and production of consumer goods. In the design of high speed systems there are two key considerations: power transmission and motion control. Although there is considerable computer-based support for the design of systems to achieve requirements of power transmission, there is only limited support for the design of systems to deliver complex motion control. This is particularly the case where mechanism and linkage systems are considered in order to achieve large displacements and intricate paths involving reentrant and reciprocating components. One explanation for this relative lack of supportive tools is the underlying reasoning and analysis techniques implemented within many commercial and research software environments. To overcome these limitations a constraint-based approach has been employed to provide the fundamental elements of a design environment for mechanisms and machine systems. The design environment provides support for the transition from concept to embodiment stages of the design process and the subsequent stages of detailed design and optimization. In contrast to many research approaches the design environment presented in this paper has been created and developed through close collaboration with industry and through extensive application to real design scenarios. First, the underlying representations and methods are presented. The fundamental elements of the design environment are then described and its capabilities discussed with particular reference to the use of constraints in design.
Volcanic processes as alternative mechanisms of landform development at a candidate crater‐lake site near Tyrrhena Patera, Mars
Authors: Leverington David W.
Published: November 2006

Palos crater, a prominent candidate crater‐lake site in the Hesperia region of Mars, is located at the mouth of a sinuous inlet channel that extends from the northern flanks of Tyrrhena Patera. Previous studies of this site have concluded that channels and basin‐infill units likely formed through aqueous processes that partly involved karst‐like removal of materials in the subsurface by the flow of groundwater. As with many locales on Mars, the aqueous processes hypothesized to have been involved in the formation and evolution of terrain features are compelling. However, the characteristics of this site suggest that an alternative set of mechanisms for landform development should be considered alongside aqueous hypotheses. The main attributes of channels and infill of the central crater include: (1) an association with a very large volcanic rise to the south; (2) the existence of roofed segments of the main inlet channel; and (3) infill of the central crater and outlet channel by materials that have characteristics consistent with those expected of volcanic plains. These general attributes are consistent with formation through or in association with processes that involved the flow of lava. Although a volcanic model may account for the presence and basic nature of landforms previously considered supportive of a paleolake interpretation of the site, an overprint of dendritic valley networks on parts of the inlet system suggests that aqueous processes may have also acted in the evolution of the site. A complex interrelation between past igneous and aqueous processes at this site is possible.
Near real‐time predictions of the arrival at Earth of flare‐related shocks during Solar Cycle 23
Authors: McKenna‐Lawlor S. M. P. , Dryer M. , Kartalev M. D. , Smith Z. , Fry C. D. , Sun W. , Deehr C. S. , Kecskemety K. , Kudela K.
Published: November 2006

The arrival times at Earth of 166 flare‐related shocks identified exiting the Sun (using metric radio drift data) during the maximum phase of Solar Cycle 23, were forecast in near‐real time using the Shock Time of Arrival Model (STOA), the Interplanetary Shock Propagation Model (ISPM) and the Hakamada‐Akasofu‐Fry Model (version 2, HAFv.2). These predictions are compared with the arrival at L1 of shocks recorded in plasma and magnetic data aboard the ACE spacecraft. The resulting correspondences are graded following standard statistical methods. Among other parameters, a representative reference metric defined by {(“hits” + “correct nulls”) × 100}/(total number of predictions) is used to describe the success rates of the predictions relative to the measurements. Resulting values for STOA, ISPM, and HAFv.2 were 50%, 57%, and 51%, respectively, for a hit window of ±24 hours. On increasing the statistical sample by 173 events recorded during the rise phase of the same cycle, corresponding success rates of 54%, 60%, and 52%, respectively, were obtained. A χ2 test shows these results to be statistically significant at better than the 0.05 level. The effect of decreasing/increasing the size of the hit window is explored and the practical utility of shock predictions considered. Circumstances under which the models perform well/poorly are investigated through the formation, and statistical analysis, of various event subsets, within which the constituent shocks display common characteristics. The results thereby obtained are discussed in detail in the context of the limitations that affect some aspects of the data utilized in the models.
A fast‐propagating, large‐scale atmospheric gravity wave observed in the WAVE2004 campaign
Authors: Kubota Minoru , Kawamura Seiji , Abo Makoto , Koizumi Yoshiko , Murayama Yasuhiro , Yamamori Miho , Shiokawa Kazuo , Otsuka Yuichi , Uchiumi Michihiro , Igarashi Kiyoshi , Abe Takumi , Oyama Koh‐Ichiro , Iwagami Naomoto
Published: November 2006

The Waves in Airglow Campaign in 2004 (WAVE2004), which aimed to elucidate the formation process of waves in airglow structures from both dynamical and chemical perspectives, was conducted using rocket‐borne and ground‐based instruments in Japan on 17 January 2004. In this experiment, we observed a large‐scale atmospheric gravity wave (AGW), which appeared in both the vertical profiles of sodium density obtained by a Na lidar and the horizontal distributions of airglow emission obtained by an all‐sky imager (ASI). Vertical propagation of the AGW accompanied by a shortening of its vertical wavelength was clearly visualized using the Na lidar data. The horizontal wavelength, horizontal phase velocity, period, and propagation direction of the AGW were estimated from the ASI data as 673–774 km, 107–122 m/s, ∼1.75 hours, and north‐northeastward, respectively. Using these parameters and the MF radar wind, vertical wavelengths of the wave were calculated from the dispersion relation of gravity waves. The calculated vertical wavelengths were comparable at altitudes of 85.5 km and 93.25 km to those estimated from the variation of the sodium density. Using a simple ray tracing technique, the AGW was traced back to the southern edge of the distorted jet stream near tropopause. This result strongly suggests that an unstable baroclinic wave associated with ageostrophic motions in the jet stream was the wave source of the large‐scale AGW observed in the WAVE2004.