bluuebunny/crossref_metadata_2025 huggingface dataset:
EXPERIMENTAL AND ANALYTICAL ESTIMATES OF FATIGUE CRACK CLOSURE IN AN ALUMINIUM‐COPPER ALLOY PART I: LASER INTERFEROMETRY AND ELECTRON FRACTOGRAPHY
Authors: Ashbaugh N. E. , Dattaguru B. , Khobaib M. , Nicholas T. , Prakash R. V. , Ramamurthy T. S. , Seshadri B. R. , Sunder R.
Published: February 2008

Abstract— Results of an experimental estimation of the crack closure stress, using electron fractography and laser interferometry for CT specimens of an aluminium‐copper alloy are presented in this paper. Crack closure stress was estimated at stress ratios of 0.1, 0.3, 0.5 and 0.7 using programmed load sequences. In addition, the crack closure stress was estimated for a simple random load sequence. Scanning and transmission electron fractography provided a similar estimate of crack closure, with the later technique providing better quality fractographs. Laser‐interferometry based estimates were closer to fractographic estimates when the crack‐tip is very close to the micro‐indent axis. In addition, laser‐interferometry based estimates of the crack opening stress for a random load sequence, confirmed the possibility of a cycle‐by‐cycle variation of the crack opening stress.
The ‘digital natives’ debate: A critical review of the evidence
Authors: Bennett Sue , Maton Karl , Kervin Lisa
Published: February 2008

The idea that a new generation of students is entering the education system has excited recent attention among educators and education commentators. Termed ‘digital natives’ or the ‘Net generation’, these young people are said to have been immersed in technology all their lives, imbuing them with sophisticated technical skills and learning preferences for which traditional education is unprepared. Grand claims are being made about the nature of this generational change and about the urgent necessity for educational reform in response. A sense of impending crisis pervades this debate. However, the actual situation is far from clear. In this paper, the authors draw on the fields of education and sociology to analyse the digital natives debate. The paper presents and questions the main claims made about digital natives and analyses the nature of the debate itself. We argue that rather than being empirically and theoretically informed, the debate can be likened to an academic form of a ‘moral panic’. We propose that a more measured and disinterested approach is now required to investigate ‘digital natives’ and their implications for education.
Wages and Contracting Out: Does the Law of One Price Hold?
Authors: Berlinski Samuel
Published: February 2008

We find that, conditioning on industry of assignment, cleaners and security guards who participate in activities organized by contract companies earn 15 and 17 per cent less, respectively, than workers in those activities organized in‐house. These estimates are hardly affected by the inclusion of a set of jointly statistically significant exogenous variables. We can expect that most of the productive traits that characterize a task are transferred to the contractor in the process of contracting out a cleaning or security task. Thus, our findings are hard to rationalize by a simple competitive labour market setting where the law of one price holds.
The Ethnographic Contribution to Understanding Co‐worker Relations
Authors: Hodson Randy
Published: February 2008

Relations among co‐workers are becoming both more important and more complex in modern workplaces as authority over job decisions is shifted from supervisors to quasi‐independent teams. The author develops a model of co‐worker relations that recognizes these changes and evaluates this model using data content coded from the full population of published book‐length workplace ethnographies (N = 204). Confirmatory factor analysis techniques support the existence of three distinct aspects of co‐worker relations: cohesiveness, conflict and peer supervision. The most important determinants of co‐worker relations are employee involvement programmes and management behaviour. Returning to specific case studies allows a theoretical elaboration of how employee involvement and management behaviour condition co‐worker relations. The author concludes by noting the importance of intellectual exchanges between qualitative and quantitative methods for generating new advances in the study of work and employment relations.
Head Up, Foot Down
Authors: Estes Zachary , Verges Michelle , Barsalou Lawrence W.
Published: February 2008

Many objects typically occur in particular locations, and object words encode these spatial associations. We tested whether such object words (e.g., head, foot) orient attention toward the location where the denoted object typically occurs (i.e., up, down). Because object words elicit perceptual simulations of the denoted objects (i.e., the representations acquired during actual perception are reactivated), we predicted that an object word would interfere with identification of an unrelated visual target subsequently presented in the object's typical location. Consistent with this prediction, three experiments demonstrated that words denoting objects that typically occur high in the visual field hindered identification of targets appearing at the top of the display, whereas words denoting low objects hindered target identification at the bottom of the display. Thus, object words oriented attention to and activated perceptual simulations in the objects' typical locations. These results shed new light on how language affects perception.
The Effect of Visual Search Efficiency on Response Preparation
Authors: Woodman Geoffrey F. , Kang Min-Suk , Thompson Kirk , Schall Jeffrey D.
Published: February 2008

Most models assume that response time (RT) comprises the time required for successive processing stages, but they disagree about whether information is transmitted continuously or discretely between stages. We tested these alternative hypotheses by measuring when movement-related activity began in the frontal eye field (FEF) of macaque monkeys performing visual search. Previous work showed that RT was longer when visual neurons in FEF took longer to select the target, a finding consistent with prolonged perceptual processing during less efficient search. We now report that the buildup of saccadic movement-related activity in FEF is delayed in inefficient visual search. Variability in the delay of movement-related activity accounted for the difference in RT between search conditions and for the variability of RT within conditions. These findings provide neurophysiological support for the hypothesis that information is transmitted discretely between perceptual and response stages of processing during visual search.
Finding Words and Rules in a Speech Stream
Authors: Toro Juan M. , Nespor Marina , Mehler Jacques , Bonatti Luca L.
Published: February 2008

We have proposed that consonants give cues primarily about the lexicon, whereas vowels carry cues about syntax. In a study supporting this hypothesis, we showed that when segmenting words from an artificial continuous stream, participants compute statistical relations over consonants, but not over vowels. In the study reported here, we tested the symmetrical hypothesis that when participants listen to words in a speech stream, they tend to exploit relations among vowels to extract generalizations, but tend to disregard the same relations among consonants. In our streams, participants could segment words on the basis of transitional probabilities in one tier and could extract a structural regularity in the other tier. Participants used consonants to extract words, but vowels to extract a structural generalization. They were unable to extract the same generalization using consonants, even when word segmentation was facilitated and the generalization made simpler. Our results suggest that different signal-driven computations prime lexical and grammatical processing.
The Best Men Are (Not Always) Already Taken
Authors: Bressan Paola , Stranieri Debora
Published: February 2008

Because men of higher genetic quality tend to be poorer partners and parents than men of lower genetic quality, women may profit from securing a stable investment from the latter, while obtaining good genes via extrapair mating with the former. Only if conception occurs, however, do the evolutionary benefits of such a strategy overcome its costs. Accordingly, we predicted that (a) partnered women should prefer attached men, because such men are more likely than single men to have pair-bonding qualities, and hence to be good replacement partners, and (b) this inclination should reverse when fertility rises, because attached men are less available for impromptu sex than single men. In this study, 208 women rated the attractiveness of men described as single or attached. As predicted, partnered women favored attached men at the low-fertility phases of the menstrual cycle, but preferred single men (if masculine, i.e., advertising good genetic quality) when conception risk was high.
More Than Meets the Eye
Authors: Dessalegn Banchiamlack , Landau Barbara
Published: February 2008

We investigated the effects of language on vision by focusing on a well-known problem: the binding and maintenance of color-location conjunctions. Four-year-olds performed a task in which they saw a target (e.g., a split square, red on the left and green on the right) followed by a brief delay and then were asked to find the target in an array including the target, its reflection (e.g., red on the right and green on the left), and a square with a different geometric split. Errors were overwhelmingly reflections. This finding shows that the children failed to maintain color-location conjunctions. Performance improved when targets were accompanied by sentences specifying color and direction (e.g., “the red is on the left”), but not when the conjunction was highlighted using a nonlinguistic cue (e.g., flashing, pointing, changes in size), nor when sentences specified a nondirectional relationship (e.g., “the red is touching the green”). The relation between children's matching performance and their long-term knowledge of directional terms suggests two distinct mechanisms by which language can temporarily bridge delays, providing more stable representations.
Semiparametrically Efficient Inference Based on Signs and Ranks for Median-Restricted Models
Authors: Hallin Marc , Vermandele Catherine , Werker Bas J. M.
Published: February 2008

Since the pioneering work of Koenker and Bassett, median-restricted models have attracted considerable interest. Attention in these models, so far, has focused on least absolute deviation (auto-)regression quantile estimation and the corresponding sign tests. These methods use a pseudolikelihood that is based on a double-exponential reference density and enjoy quite attractive properties of root n consistency (for estimators) and distribution freeness (for tests). The paper extends these results to general, i.e. not necessarily double-exponential, reference densities. Using residual signs and ranks (not signed ranks) and a general reference density f, we construct estimators that remain root n consistent, irrespective of the true underlying density g (i.e. also for g /=f). However, instead of reaching semiparametric efficiency bounds under double-exponential g, they reach these bounds when g coincides with the chosen reference density f. Moreover, we show that choosing reference densities other than the double-exponential in applications can lead to sizable gains in efficiency. The particular case of median regression is treated in detail; extensions to general quantile regression, heteroscedastic errors and time series models are briefly described. The performance of the method is also assessed by simulation and illustrated on financial data.
α-Investing: a Procedure for Sequential Control of Expected False Discoveries
Authors: Foster Dean P. , Stine Robert A.
Published: February 2008

α-investing is an adaptive sequential methodology that encompasses a large family of procedures for testing multiple hypotheses. All control mFDR, which is the ratio of the expected number of false rejections to the expected number of rejections. mFDR is a weaker criterion than the false discovery rate, which is the expected value of the ratio. We compensate for this weakness by showing that α-investing controls mFDR at every rejected hypothesis. α-investing resembles α-spending that is used in sequential trials, but it has a key difference. When a test rejects a null hypothesis, α-investing earns additional probability towards subsequent tests. α-investing hence allows us to incorporate domain knowledge into the testing procedure and to improve the power of the tests. In this way, α-investing enables the statistician to design a testing procedure for a specific problem while guaranteeing control of mFDR.
Sex Hormones and Sexual Desire
Authors: GILES JAMES
Published: February 2008

Some scholars attempt to explain sexual desire biologically by claiming that sex hormones play a necessary causal role in sexual desire. This can be claimed even if sexual desire is seen to be an experience. Yet the evidence for such biological essentialism is inadequate. With males the loss of sexual desire following hormonal changes can easily be explained in terms of social stigmas that are attached to the physiological situation. Concerning females, the relevance of sex hormones here is even more unclear. Although some women seem to have fluctuations in sexual desire during hormonal changes, other women do not. Even where there are such fluctuations these can be explained by responses to other physiological changes or the meanings that are attached to the situation. Research with non‐human primates supports this view of the non‐essential relation of sex hormones to sexual desire. A phenomenology of sex hormones is given that shows a possible non‐essential relation between sex hormones and sexual desire. Here hormone induced excitations in the genitals may or may not lead to sexual desire depending on the meaning they are given within awareness. This suggests that sexual desire has its origin in the meanings we give our biology and not in our biology itself.
Perturbation Analysis: A Simple Method for Filtering SNPs with Erroneous Genotyping in Genome‐Wide Association Studies
Authors: Teo Y. Y. , Small K. S. , Clark T. G. , Kwiatkowski D. P.
Published: February 2008

We introduce a simple and yet scientifically objective criterion for identifying SNPs with genotyping errors due to poor clustering. This yields a metric for assessing the stability of the assigned genotypes by evaluating the extent of discordance between the calls made with the unperturbed and perturbed intensities. The efficacy of the metric is evaluated by: (1) estimating the extent of over‐dispersion of the Hardy‐Weinberg equilibrium chi‐square test statistics; (2) an interim case‐control study, where we investigated the efficacy of the introduced metric and standard quality control filters in reducing the number of SNPs with evidence of phenotypic association which are attributed to genotyping errors; (3) investigating the call and concordance rates of SNPs identified by perturbation analysis which have been genotyped on both Affymetrix and Illumina platforms. Removing SNPs identified by the extent of discordance can reduce the degree of over‐dispersion of the HWE test statistic. Sensible use of perturbation analysis in an association study can correctly identify SNPs with problematic genotyping, reducing the number required for visual inspection. SNPs identified by perturbation analysis had lower call and concordance rates, and removal of these SNPs significantly improved the performance for the remaining SNPs.
Conflict, cheats and the persistence of symbioses
Authors: Douglas Angela E.
Published: February 2008

Many symbioses are widespread, abundant, and evolutionarily persistent. This is despite unambiguous evidence for conflict between the partners and the existence of cheats that use benefits derived from their partners while providing reduced or no services in return. Evidence from a diversity of associations suggests that symbioses are robust to cheating in several ways. Some symbioses persist despite conflict and cheating because of the selective advantage of cost‐free interactions (also known as byproduct mutualistic interactions), which incur no conflict. There is also evidence for the suppression of cheating by sanctions imposed by partners in some symbioses, and vertical transmission has been shown experimentally to promote traits that enhance partner performance. It is argued that these processes contribute to the apparent rarity of evolutionary transitions from symbiosis to parasitism. There is strong phylogenetic evidence for the evolutionary reversion of various symbiotic organisms to free‐living lifestyles, but at least some of these transitions can be attributed to selection pressures other than within‐symbiosis conflict. The principal conclusion is that, although conflict is common in symbioses, it is generally managed and contained.

ContentsSummary849I.Introduction850II.Conflict and cheats850III.Symbiotic interactions without cost852IV.Routes to conflict resolution854V.Discussion856Acknowledgements857References857
Postpartum perineal repair performed by midwives: a randomised trial comparing two suture techniques leaving the skin unsutured*
Authors: Kindberg S , Stehouwer M , Hvidman L , Henriksen TB
Published: February 2008

Objective  To compare a continuous suture technique with interrupted stitches using inverted knots for postpartum perineal repair of second‐degree lacerations and episiotomies.

Design  A double‐blind randomised controlled trial.

Setting  A Danish university hospital with more than 4800 deliveries annually.

Population  A total of 400 healthy primiparous women with a vaginal delivery at term.

Method  Randomisation was computer‐controlled. Structured interviews and systematic assessment of perineal healing were performed by research midwives blinded to treatment allocation at 24–48 hours, 10 days and 6 months postpartum. Pain was evaluated using a visual analogue scale and the McGill Pain Questionnaire. Wound healing was evaluated using the REEDA scale and by assessment of gaping wounds >0.5 cm. Analysis complied with the intention‐to‐treat principle.

Main outcome measures  The primary outcome was perineal pain 10 days after delivery. Secondary outcomes were wound healing, patient satisfaction, dyspareunia, need for resuturing, time elapsed during repair and amount of suture material used.

Results  A total of 400 women were randomised; 5 women withdrew their consent, leaving 395 for follow up. The follow‐up rate was 98% for all assessments after delivery. No difference was seen in perineal pain 10 days after delivery. No difference was seen in wound healing, patient satisfaction, dyspareunia or need for resuturing. The continuous suture technique was significantly faster (15 versus 17 minutes, P = 0.03) and less suture material was used (one versus two packets, P < 0.01).

Conclusion  Interrupted, inverted stitches for perineal repair leaving the skin unsutured appear to be equivalent to the continuous suture technique in relation to perineal pain, wound healing, patient satisfaction, dyspareunia and need for resuturing. The continuous technique, however, is faster and requires less suture material, thus leaving it the more cost‐effective of the two techniques evaluated.
Intracardiac injection of potassium chloride as method for feticide: experience from a single UK tertiary centre
Authors: Pasquini L , Pontello V , Kumar S
Published: February 2008

We report our experience with intracardiac administration of potassium chloride as safe and effective method for late termination of pregnancy (TOP) and to document the indications for feticide in a major tertiary unit. During the study period (January 2000 and December 2005), 239 late terminations of pregnancy were performed at a median gestational age of 22+6 weeks (range 20+6 to 36+3 weeks). The most frequent indication was represented by aneuploidy (24.3%), followed by brain abnormalities (17.6%). Maternal indications were responsible for 2.9% of the total number of terminations. No maternal complications occurred and complete asystole was achieved in all cases with a median volume of potassium chloride of 4.7 ml (range 2–10 ml). Potassium chloride injected directly in the left ventricle induces immediate asystole, and it is a safe and effective method of TOP. Interestingly, despite the widespread introduction of aneuploidy screening, chromosomal abnormalities, particularly trisomy 21, still represent the major indication for late TOP.
Crocus sativus L. (saffron) in the treatment of premenstrual syndrome: a double‐blind, randomised and placebo‐controlled trial
Authors: Agha‐Hosseini M , Kashani L , Aleyaseen A , Ghoreishi A , Rahmanpour H , Zarrinara AR , Akhondzadeh S
Published: February 2008

Objective  The aim of this double‐blind and placebo‐controlled trial was to investigate whether saffron (stigma of Crocus sativus L.) could relieve symptoms of premenstrual syndrome (PMS).

Design  Double‐blind, randomised and placebo‐controlled trial.

Setting  Departments of Gynaecology/Obstetrics and Psychiatry, Tehran and Zanjan University of Medical Sciences.

Population  Women aged 20–45 years with regular menstrual cycles and experience of PMS symptoms for at least 6 months were eligible for the study.

Method  Women were randomly assigned to receive capsule saffron 30 mg/day (15 mg twice a day; morning and evening) (group A) or capsule placebo (twice a day) for a two menstrual cycles (cycles 3 and 4).

Main outcome measures  The primary outcome measure was the Daily Symptom Report, and secondary outcome measure was the Hamilton Depression Rating Scale.

Results  In this trial, saffron was found to be effective in relieving symptoms of PMS. A significant difference was observed in efficacy of saffron in cycles 3 and 4 in the Total Premenstrual Daily Symptoms and Hamilton Depression Rating Scale.

Conclusion  The results of this study indicate the efficacy of C. sativus L. in the treatment of PMS. However, a tolerable adverse effects profile of saffron may well confirm the application of saffron as an alternative treatment for PMS. These results deserved further investigations.
Insensitivity to glutamate neurotoxicity mediated by NMDA receptors in association with delayed mitochondrial membrane potential disruption in cultured rat cortical neurons
Authors: Kambe Yuki , Nakamichi Noritaka , Georgiev Danko D. , Nakamura Nobuhiro , Taniura Hideo , Yoneda Yukio
Published: February 2008

We have attempted to elucidate mechanisms underlying differential vulnerability to glutamate (Glu) using cultured neurons prepared from discrete structures of embryonic rat brains. Brief exposure to Glu led to a significant decrease in the mitochondrial activity in hippocampal neurons cultured for 9 or 12 days at 10 μM to 1 mM with an apoptosis‐like profile, without markedly affecting that in cortical neurons. Brief exposure to Glu also increased lactate dehydrogenase release along with a marked decrease in the number of cells immunoreactive for a neuronal marker protein in hippocampal, but not cortical, neurons. Similar insensitivity was seen to the cytotoxicity by NMDA, but not to that by tunicamycin, 2,4‐dinitrophenol, hydrogen peroxide or A23187, in cortical neurons. However, NMDA was more efficient in increasing intracellular free Ca2+levels in cortical neurons than in hippocampal neurons. Antagonists for neuroprotective metabotropic Glu receptors failed to significantly affect the insensitivity to Glu, while NMDA was more effective in disrupting mitochondrial membrane potentials in hippocampal than cortical neurons. These results suggest that cortical neurons would be insensitive to the apoptotic neurotoxicity mediated by NMDA receptors through a mechanism related to mitochondrial membrane potentials, rather than intracellular free Ca2+levels, in the rat brain.
Transport of multiple nicotinic acetylcholine receptors in the rat optic nerve: high densities of receptors containing α6 and β3 subunits
Authors: Cox Brandon C. , Marritt Andrea M. , Perry David C. , Kellar Kenneth J.
Published: February 2008

Neuronal nicotinic acetylcholine receptors (nAChRs) are abundant in the rat retina and at least seven heteromeric subtypes have been detected. Axons of retinal ganglion cells form the optic nerve and innervate areas of the brain important for visual processing, including the lateral geniculate nucleus, the superior colliculus, and the pretectal nucleus. Development of eye‐specific layers in these projection areas are dependent upon retinal waves which are initially mediated by nAChRs [Felleret al.,Science272 (1996), 1182;Pennet al.,Science279 (1998), 2108;Bansalet al.,J. Neurosci.20 (2000), 7672]. Unilateral eye‐enucleation studies in the rat indicate that nAChRs are on the terminals of optic nerve axons, where they may mediate influences of acetylcholine on visual pathways. In this study, we use radioligand binding and immunoprecipitation with subunit‐selective antibodies to investigate the subunit composition of nAChRs in the rat optic nerve. We found multiple nAChR subtypes in the optic nerve, all of which contain the β2 subunit. Most of these receptors are mixed heteromeric subtypes, composed of at least three different subunits. Included among these subtypes is the highest percentage and density of α6‐ and β3‐containing nAChRs of any area of the rat CNS that has been reported.
Efficacy and Tolerability of Coadministration of Rizatriptan and Acetaminophen vs Rizatriptan or Acetaminophen Alone for Acute Migraine Treatment
Authors: Freitag Fred , Diamond Merle , Diamond Seymour , Janssen Imke , Rodgers Anthony , Skobieranda Franck
Published: February 2008

Objective.—To evaluate the efficacy and tolerability of coadministration of rizatriptan and acetaminophen in the acute treatment of migraine.

Background.—Rizatriptan is a selective 5‐HT1B/1Dagonist approved for the acute treatment of migraine. Acetaminophen has been studied for acute migraine treatment. In consideration of the prominent central and peripheral mechanisms in migraine, the use of “multi‐mechanism therapy” is gaining momentum in the treatment of acute migraine attacks.

Study Design.—This was a randomized, double‐blind, placebo‐controlled trial conducted at 10 centers. Eligible patients with migraine according to International Headache Society criteria treated a single migraine attack of moderate or severe intensity within 4 h from pain onset. Patients were randomized into 1 of 4 groups (rizatriptan 10 mg + acetaminophen 1000 mg [RA], rizatriptan alone [R], acetaminophen alone [A], and placebo [P]). There were 3 co‐primary hypotheses tested sequentially for 2‐h pain relief: (1) RA would be superior to P; (2) if the first was fulfilled, RA would be superior to A; and (3) if the first 2 were fulfilled, RA would be superior to R.

Results.—Of 173 patients who treated a migraine, 123 patients (71.5%) achieved pain relief within 2 h. RA (90%) was significantly better than P (46%) and A (70%), but only numerically better than R (77%) for 2‐h pain relief. No significant differences were seen between the active treatment groups in adverse events.

Conclusion.—Rizatriptan coadministered with acetaminophen achieved 2 of the 3 primary hypotheses, proving superior to both acetaminophen and placebo for 2‐h pain relief, but failing to achieve superiority to rizatriptan alone. RA was as well tolerated as each of the individual agents.
Histamine‐N‐Methyl Transferase Polymorphism and Risk for Migraine
Authors: García‐Martín Elena , Martínez Carmen , Serrador Mercedes , Alonso‐Navarro Hortensia , Navacerrada Francisco , Agúndez José A.G. , Jiménez‐Jiménez Félix Javier
Published: February 2008

Background/Objectives.— Histamine has been implicated in the pathogenesis of migraine. In the CNS, histamine is almost exclusively metabolized by the polymorphic enzyme histamine N‐methyltransferase (HNMT). The HNMT gene (chromosome 2q22.1), shows diverse single nucleotide polymorphisms. One of these, located in exon 4 C314T, causes the amino acid substitution Thr105Ile, related to decreased enzyme activity. The aim of this study was to investigate the possible association between HNMT polymorphism and the risk for migraine.

Methods.— We studied the frequency of the HNMT genotypes and allelic variantes in 197 patients with migraine and 245 healthy controls using a PCR‐RLFP method.

Results.— The frequencies of the HNMT genotypes and allelic variants did not differ significantly between migraine patients and controls, and were unrelated with the age of onset of migraine attacks, gender, personal history of allergic diseases, family history of migraine, or presence of aura.

Conclusion.— The results of the present study suggest that HNMT polymorphism in not related with the risk for migraine.
CHANGES IN NUTRIENT CONTENT OFPALMARIA PALMATAIN RESPONSE TO VARIABLE LIGHT AND UPWELLING IN NORTHERN SPAIN1
Authors: Martínez Brezo , Rico Jose M.
Published: February 2008

Light has been identified as one of the main factors affecting seaweed ecophysiology. We investigated the dependence of nutrient metabolism on sun and shade light conditions and whether episodes of upwelling of nutrient‐rich subsuperficial water could reduce the summer nutrient limitation driving physiological changes inPalmaria palmata(L.) Kuntze. We measured the major nutrient pools, photosynthetic pigments, and light curves, under sun and shade conditions during a summer period when one upwelling was recorded. The redundancy analysis (RDA) produced two clear groups: sun‐ and shade‐acclimated algae. Light was the major predictive factor. Sun‐acclimated algae exhibited higher carbon (C) and lower nitrogen (N) and phosphorus (P) content in association with the storage of floridoside (main C reserve) to benefit from higher irradiance (under nutrient limitation). Among N pools, N reserves (phycoerythrin, nitrate) were a lower proportion of the total N in sun‐acclimated algae, suggesting their degradation to fulfill the N demands of the cell. The orthophosphate content was also lower in sun‐acclimated algae, indicating its utilization as a nutrient reserve. In contrast, N within cell walls and membranes and chlacontributed to a similar proportion of the total N in sun‐ and shade‐acclimated algae, suggesting a response to sustain cell integrity. Transient high nutrient concentration due to the upwelling was unrelated to the nutrient content of the thallus. The storage of C as floridoside from high light exposure was shown to be the driving force for the metabolic adjustment ofP. palmataat the end of summer before the onset of dormancy.
NOVEL PELLICLE SURFACE PATTERNS ON EUGLENA OBTUSA (EUGLENOPHYTA) FROM THE MARINE BENTHIC ENVIRONMENT: IMPLICATIONS FOR PELLICLE DEVELOPMENT AND EVOLUTION1
Authors: Esson Heather J. , Leander Brian S.
Published: February 2008

Euglena obtusa F. Schmitz possesses novel pellicle surface patterns, including the greatest number of strips (120) and the most posterior subwhorls of strip reduction in any euglenid described so far. Although the subwhorls form a mathematically linear pattern of strip reduction, the pattern observed here differs from the linear pattern described for Euglena mutabilis F. Schmitz in that it contains seven linear subwhorls, rather than three, and is developmentally equivalent to three whorls of exponential reduction, rather than two. These properties imply that the seven‐subwhorled linear pattern observed in E. obtusa is evolutionarily derived from an ancestral bilinear pattern, rather than from a linear pattern, of strip reduction. Furthermore, analysis of the relative lateral positions of the strips forming the subwhorls in E. obtusa indicates that (1) the identity (relative length, lateral position, and maturity) of each strip in any mother cell specifies that strip’s identity in one of the daughter cells following pellicle duplication and cell division, (2) the relative length of any given pellicle strip regulates the length of the nascent strip it will produce during pellicle duplication, and (3) pellicle pores develop within the heels of the most mature pellicle strips. These observations suggest that continued research on pellicle development could eventually establish an ideal system for understanding mechanisms associated with the morphogenesis and evolution of related eukaryotic cells.
Electrocardiographic Characteristics of the Variants of Idiopathic Left Ventricular Outflow Tract Ventricular Tachyarrhythmias
Authors: KUMAGAI KOJI , FUKUDA KOJI , WAKAYAMA YUJI , SUGAI YOSHINAO , HIROSE MASANORI , YAMAGUCHI NOBUHIRO , TAKASE KEI , YAMAUCHI YASUTERU , TAKAHASHI ATSUSHI , AONUMA KAZUTAKA , SHIMOKAWA HIROAKI
Published: February 2008

Background: Despite similar QRS morphology, idiopathic repetitive monomorphic ventricular tachyarrhythmias (VTs) of left ventricular outflow tract (LVOT) are known to have the variants of different adjacent origins, including the aorto‐mitral continuity (AMC), anterior site around the mitral annulus (MA), aortic sinus cusps (ASC), and epicardium. However, the electrocardiographic characteristics of those variants previously have not been evaluated fully.

Methods and Results: Based on the mapping site and successful ablation in 45 consecutive patients with LVOT‐VTs, we classified them into VTs of AMC (n = 3), MA (n = 8), ASC (n = 32), and epicardial (n = 2) origins. In all patients, we performed activation mapping and an electrocardiographic analysis. All AMC‐VTs patients had monophasic R waves in almost all the precordial leads, while those with anterior MA‐VTs had an Rs pattern in some precordial leads except for lead V6, and those with ASC‐VTs had a variable transitional zone in leads V1–4. There was no S wave in lead V6 in any group except for one patient with anterior MA‐VTs. The intrinsicoid deflection time in the AMC‐VTs patients and anterior MA‐VTs patients was significantly greater than in those with ASC‐VTs (P < 0.05). There was no significant difference in the R‐wave amplitude in the inferior leads among the groups. Successful radiofrequency catheter ablation (RFCA) was achieved in all patients except for in those with epicardial origin VT.

Conclusions: Despite many morphological similarities, the LVOT‐VTs originating from the AMC, anterior MA and ASC could be identified by our proposed electrocardiographic characteristics in order to safely perform RFCA.
Left Atrial Contractility is Preserved After Successful Circumferential Pulmonary Vein Ablation in Patients with Atrial Fibrillation
Authors: PEREA ROSARIO J. , TAMBORERO DAVID , MONT LLUIS , De CARALT TERESA M. , ORTIZ JOSE T. , BERRUEZO ANTONIO , MATIELLO MARIA , SITGES MARTA , VIDAL BARBARA , SANCHEZ MARCELO , BRUGADA JOSEP
Published: February 2008

Introduction: Circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF) consists of creating extensive lesions in the left atrium (LA). The aim of the study was to evaluate changes in LA contractility after ablation and their relationship with procedure outcome.

Methods and Results: A series of 90 consecutive patients underwent cardiac magnetic resonance imaging (MRI) before and 4–6 months after CPVA. Only patients in sinus rhythm during both imaging acquisitions were included in the study to measure LA end‐diastolic (LAmax) and LA end‐systolic (LAmin) volumes. Fifty‐five patients were finally analyzed (41 men, 52 ± 11 years, 74% paroxysmal AF). During a mean follow‐up of 12 ± 7 months and after 1.2 ± 0.3 ablation procedures, 38 patients (69%) were arrhythmia‐free (group I), and the remaining 17 patients had recurrences (group II). There was a significant decrease in mean LAmax volume in both groups, whereas mean LAmin volume only decreased in group I. Mean LA ejection fraction (EF) was preserved after CPVA in group I (40 ± 11% vs 38 ± 10%; P = 0.27) but decreased in patients with arrhythmia recurrences (37 ± 10% vs 27 ± 10%; P < 0.001). In fact, LA EF remained stable or increased in 68% of patients without arrhythmia recurrences.

Conclusions: LAmax volume reduction following CPVA occurs regardless of the clinical efficacy of the procedure, whereas mean LAmin volume only decreased in patients without recurrences. LA EF was preserved or even increased in most patients with successful CPVA.
An Acute Model for Atrial Fibrillation Arising from a Peripheral Atrial Site: Evidence for Primary and Secondary Triggers
Authors: SCHERLAG BENJAMIN J. , HOU YING‐LONG , LIN JIAXIONG , LU ZHIBING , ZACHARIAS SONI , DASARI TARUN , NIU GUODONG , GHIAS MUHAMMAD , PATTERSON EUGENE , JACKMAN WARREN M. , LAZZARA RALPH , PO SUNNY S.
Published: February 2008

Background: We previously demonstrated that acetylcholine (Ach) injected into cardiac ganglionated plexi (GP) causes pulmonary vein (PV) ectopy initiating atrial fibrillation (AF).

Objective: To determine the effects of Ach applied at non‐PV sites.

Methods: Overall, 54 dogs were anesthetized with Na‐pentobarbital. A right and left thoracotomy allowed the placement of multielectrode catheters to record from the superior PVs, mid portion of the atrium and the atrial appendages (AA). A monophasic action potential (MAP) was recorded from the AA. Ach (1, 10, 100 mM) was applied sequentially to the AA.

Results: In 19 of 26 animals, Ach 100 mM on the right (n = 15) or left (n = 4) AA induced focal, sustained AF (≥10 minutes) with rapid regular firing (cycle length = 37 ± 7 ms) at the AA. A clamp with teeth placed across the AA caused arrest in the AA. However, AF was sustained only when PV sites adjacent to the GP manifested complex fractionated atrial electrograms (CFAE). Clamping the AA prior to Ach (100 mM) application resulted in focal AF arising at the PVs but not at the AA. When a clamp without teeth was applied prior to Ach application, no AF at either AA or PV site could be induced.

Conclusion: Isolation of the focal AF at the AA (primary trigger) by clamping caused cessation of activity in the AA, but AF continued due to secondary triggers arising from PVs. The possible mechanism(s) responsible for these findings are discussed, and various ancillary experiments (n = 28) were added to help elucidate mechanisms.
Longer and better lives for patients … and their centers: A strategy for building a home hemodialysis program
Authors: HODGE Melville H.
Published: February 2008

Physicians should prescribe the dialysis mode most likely to result in the best outcome for the end‐stage renal disease patient, not leave it to the patient or dialysis center to choose. That prescription, in order of decreasing desirability, should be for frequent home nocturnal hemodialysis, frequent home short‐daily, or least efficacious, 3x in‐center or peritoneal dialysis. Patient limitations may require prescribing a less than optimal mode. Physician‐patient discussions should focus on expected clinical outcomes and health benefits, not patient convenience or “lifestyle.” In order to overcome natural fears, qualified patients should participate in a short in‐center frequent dialysis personal clinical trial to experience the benefits. The financial health of dialysis centers will be enhanced by shifting continually inflating labor costs from the center to patients and home caregivers. This shift from 3x in‐center to frequent (optimally 6x nocturnal) home dialysis may reasonably be expected to enhance the survival and well‐being of both the patient and the center.
Long‐term outcomes of transposed basilic vein arteriovenous fistulae
Authors: MOOSSAVI Shahriar , TUTTLE Audrey B. , VACHHARAJANI Tushar J. , PLONK George , BETTMANN Michael A. , MAJEKODUNMI Omotayo , RUSSELL Gregory B. , REGAN John D. , FREEDMAN Barry I.
Published: February 2008

The need for reliable, long‐term hemodialysis vascular access remains critical. To determine the long‐term outcomes of transposed basilic vein arteriovenous fistulae (BVT) and their comparability with other vascular accesses, we determined retrospectively the primary and secondary patency rates in 58 BVT and in a total of 58 arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) at a single center. Fifty‐eight BVT were placed in 57 individuals, 69% after prior vascular access failure. Ten BVT failed before initial use and 2 patients expired with functioning accesses before dialysis initiation. In all 58 BVT, 46.8±10.8% functioned at 3 years, with median survival 30.8 months. Limiting analyses to the 46 BVT that were ultimately accessed, 3‐year primary and secondary patency rates were 38.3±7.7% and 56.5±12.6%, respectively. Lower ejection fraction (p=0.054) and greater numbers of prior permanent dialysis catheters (p=0.005) were present in those with failed BVT. Compared with AVF, BVT had similar 3‐year primary and secondary patency rates. The secondary patency rate was significantly better for BVT vs. AVG over the observation period; at 3 years, the rates were 56.5±12.6% vs. 9.1±6.0% (p=0.002), respectively. Basilic vein arteriovenous fistulae are valuable hemodialysis accesses. Although nearly 20% of newly placed BVT will not function before first use, those that are functional have median survivals exceeding 6 years, and 38% will not require intervention within 3 years of initial use.
Nondestructive Measurement of the Residual Stress Profile in Ceramic Laminates
Authors: Leoni Matteo , Ortolani Matteo , Bertoldi Massimo , Sglavo Vincenzo M. , Scardi Paolo
Published: February 2008

Millimeter‐thick symmetric ceramic laminates, designed to possess a specific through‐thickness residual stress profile, were produced by tape casting from blends of alumina, zirconia, and mullite powders. The residual stress profile was checked nondestructively by X‐ray energy‐dispersive diffraction using synchrotron white‐beam radiation. Measurement of the average stress on very small volumes (ca. 10 μm along the specimen thickness) provided results in good agreement with the design data. Moreover, the possibility of independently measuring each crystalline phase composing the laminate allowed inferences to be made on stress partition and grain–grain coupling in the laminas.
Activation of cannabinoid receptors prevents antigen‐induced asthma‐like reaction in guinea pigs
Authors: Giannini L. , Nistri S. , Mastroianni R. , Cinci L. , Vannacci A. , Mariottini C. , Passani M. B. , Mannaioni P. F. , Bani D. , Masini E.
Published: February 2008

In this study we evaluated the effects of the CB1/CB2cannabinoid receptor agonist CP55, 940 (CP) on antigen‐induced asthma‐like reaction in sensitized guinea pigs and we tested the ability of the specific CB2 receptor antagonist SR144528 (SR) and CB1 receptor antagonist AM251 (AM) to interfere with the effects of CP. Ovalbumin‐sensitized guinea pigs placed in a respiratory chamber were challenged with the antigen given by aerosol. CP (0.4 mg/kg b.wt.) was given i.p. 3 hrs before ovalbumin challenge. Sixty minutes before CP administration, some animals were treated i.p. with either AM, or SR, or both (0.1 mg/kg b.wt.). Respiratory parameters were recorded and quantified. Lung tissue specimens were then taken for histopathological and morphometric analyses and for eosinophilic major basic protein immunohistochemistry. Moreover, myeloperoxidase activity, 8‐hydroxy‐2‐deoxyguanosine, cyclic adenosine monophosphate (cAMP) and guanosine monophosphate (cGMP) levels, and CB1and CB2receptor protein expression by Western blotting were evaluated in lung tissue extracts. In the bronchoalveolar lavage fluid, the levels of prostaglandin D2and tumour necrosis factor‐α TNF‐α were measured. Ovalbumin challenge caused marked abnormalities in the respiratory, morphological and biochemical parameters assayed. Treatment with CP significantly reduced these abnormalities. Pre‐treatment with SR, AM or both reverted the protective effects of CP, indicating that both CB1and CB2receptors are involved in lung protection. The noted treatments did not change the expression of cannabinoid receptor proteins, as shown by Western blotting. These findings suggest that targeting cannabinoid receptors could be a novel preventative therapeutic strategy in asthmatic patients.
Interphotoreceptor retinoid‐binding protein as biomarker in systemic autoimmunity with eye inflictions
Authors: Descamps F. J. , Kangave D. , Cauwe B. , Martens E. , Geboes K. , Abu El‐Asrar A. , Opdenakker G.
Published: February 2008

Autoimmune diseases of the eye, exemplified by Beh cet disease and Vogt‐Koyanagi‐Harada disease, are a major cause of blindness. We studied interphotoreceptor retinoid‐binding protein (IRBP), a dominant autoimmune antigen in the eye. Aqueous humour samples from 28 patients with active uveitis were analysed for immunoglobulin G (IgG) content as a marker for blood‐ocular barrier breakdown and by gelatinase B zymography for the detection of inflammation. The data were correlated with the presence of intact IRBP (≈140 kD) as determined by Western blot analysis and with the clinical disease activity. Aqueous humour samples from control eyes and eyes with low disease activity showed positive immunoreactivity for intact IRBP. The IRBP signal weakened or disappeared with higher disease activity. Significant positive correlations were observed between disease activity and levels of gelatinase B/matrix metalloproteinase‐9 (MMP‐9) (rs= 0.713; P < 0.001) and IgG (rs= 0.580; P= 0.001). Significant negative correlations were found between levels of IRBP and disease activity (rs=−0.520; P= 0.005) and levels of MMP‐9 (rs=−0.727; P < 0.001) and of IgG (rs=−0.834; P < 0.001). Whereas neutrophil elastase converted intact IRBP into an immunoreactive 55 kD peptide in vitro, the conversion by neutrophil degranulates resembled more the in vivo context with a complete degradation of IRBP. Reversal of inflammation with immunosuppressive therapy was accompanied with reappearance of intact IRBP and disappearance of IgG and MMP‐9. The analysis of IRBP proteolysis is useful as a biomarker for uveitis and suggests that inhibition of proteinases might become a therapeutic strategy in an inflammatory context of a damaged blood‐ocular barrier.
Goose grazing selectivity along a depletion gradient
Authors: Therkildsen Ole R. , Madsen Jesper
Published: February 2008

The micro‐habilat food selectivity along a gradient of increasing grazing intensity of wintering pink‐footed geese Anser brachyrhynchus and barnacle geese Branta leucopsis foraging on winter wheat Triticum aestivum and smooth meadow grass Poa pratensis was investigated. Protein content of ungrazed primary and secondary leaves of winter wheat did not differ, whereas the protein content of tertiary leaves was significantly lower. Secondary leaves were significantly longer than both primary and tertiary leaves, whereas tertiary leaves were significantly longer than primary leaves. Protein content of primary and secondary leaves of Poa pratensis did not differ, whereas the protein content of tertiary leaves was significantly lower. Primary leaves were significantly shorter than both secondary and tertiary leaves, which did not differ significantly.

For all leaf categories, there was an increase in the removal with increasing goose grazing intensity. The geese showed a sequential selection of winter wheat leaves according to the protein content, initially preferring primary and secondary leaves, but increasingly selecting tertiary leaves of poorer quality as high‐quality leaves became depleted. Foraging on Poa pratensis. geese selected secondary leaves according to the protein content, whereas tertiary leaves were preferred to primary leaves, although these had a protein content equal to secondary leaves. This, however, may be explained by the primary leaves being too short to maintain intake rates.

It is concluded that feeding preferences cannot be established on the basis of protein contents of food plants alone and that green biomass estimates not necessarily reflect resource availability.