bluuebunny/crossref_metadata_2025 huggingface dataset:
Technonatural revolutions: the scalar politics of Franco's hydro‐social dream for Spain, 1939–1975
Authors: Swyngedouw Erik
Published: January 2007

In this paper, I seek to document and substantiate the notion of the production of socio‐natures by elaborating how Spain's modernization process after the Civil War became a deeply and very specific scalar geographical project, articulated through the production of a specific technonatural hydraulic edifice. I shall focus on the momentous transformation of the hydraulic environment during the Franco period (1939–1975) and seek to reformulate Spain's socio‐hydraulic reconstruction in the context of a double and partly contradictory ‘scalar’ politics. Two theoretically interrelated arguments guide this endeavour. On the one hand, Franco's ideological‐political mission was predicated upon national territorial integration, the eradication of regionalist or autonomist aspirations, and a concerted discursive and physical process of cultural and material national(ist) homogenization and modernization. On the other, the production of the technonatural material infrastructures of this modernizing programme was predicated upon re‐scaling the ‘networks of interest’ on which Franco's power rested from a national visionary to an internationalist geo‐economic and geo‐political imagination, articulated through Spain's integration in the US‐led Western Alliance.
Ubiquitous identities and elusive subjects: puzzles from Central Europe
Authors: Kuus Merje
Published: January 2007

This paper investigates the logic of explanation according to which identity is an attribute or a feature of subjects like states and nations. Drawing examples from the scholarship on identity in Central Europe, especially Estonia, it argues that the story by which identity is customarily told is circular, presupposing the very subject for which it seeks to give an account. The puzzle, then, is how to overcome the perspective of a subject already formed in order to account for its becoming. The paper deploys the concept of performativity to address that puzzle. Performative approaches do not treat identity as an attribute or a property of the subject – something that subjects such as individuals or states express. It conceives subjectivity explicitly in processual terms, not as a source but as an effect of identity claims. Identity then is not something that states, groups or individuals have, but something that groups and individuals do. Reframing identity research from doers to deeds opens up the discussions of actor‐ness and subjectivity without dictating what kind of subjects can be realized.
Standardized Income Inequality Data for Use in Cross‐National Research
Authors: Babones Salvatore J. , Alvarez‐Rivadulla María José
Published: January 2007

This article introduces the first version of a new, standardized data tool that can be used to test models of global income allocation, the Standardized Income Distribution Database (SIDD). It is based on a comprehensive collection of income distribution data compiled by the United Nations University's World Institute for Development Economics Research (UNU‐WIDER 2000). International and intertemporal inconsistencies in these data have historically limited its use. We estimate adjustment factors for different scopes of coverage, income definitions, and reference units which, when applied to the raw data, bring all data to a common standard based on national coverage, gross income, and household per capita inequality. Criterion validity checks confirm that these adjustments boost the correlation between measured income inequality and national social indicators. The SIDD is also clean, free of duplicates, and easy to access. The SIDD will be useful both to students reading income inequality and to those conducting broad cross‐national research on the relationship between income inequality and a range of important outcomes, such as health, criminality, and social support.
Private Property Wrongs: Uncovering the Contradictory Articulations of an Hegemonic Ideology*
Authors: Davidson Debra J.
Published: January 2007

One of the most effective sources of legitimation for privileged access to the environment and its natural resources comes in the form of hegemonic ideologies, such as private property rights. The concentratiosn of ownership and control over land and natural resources is rarely contested, because to question the rights of an industrial actor's property rights would be to question the ideological premise that private property ownership promotes societal well‐being and progress. The staying power of this and other hegemonic ideologies, however, derives from the ability to keep certain internal contradictions associated with those ideologies concealed. Using recent conceptual work on ideology, this article focuses on recent events in forest politics in northern California, to illustrate the means by which environmental catastrophe has served as a source of vulnerability to the present hegemony of the ideology of private property rights. As with other instances of environmental justice mobilization, this case illustrates how the ability to elucidate contradictions in hegemonic ideologies may provide a more potent avenue for social transformation than attempts to introduce alternative ideologies.
China: The New Global Model for Development
Authors: ZHANG WEI‐WEI
Published: January 2007

Globalization may yet repeal the Biblical adage that the poor will always be with us. But for now there are enough losers to go along with the winners that a slide back toward fragmentation and protectionism is a distinct possibility, as was also the case at the turn of the 20th century. Our contributors in this section offer their advice on how to make globalization work for everyone.
Resurrecting melancholia
Authors: Fink M. , Taylor M. A.
Published: January 2007

Objective: To define melancholia as a distinct mood disorder, identified by unremitting depressed mood, vegetative dysfunction, and psychomotor disturbances, verifiable by neuroendocrine tests, and treatable by electroconvulsive therapy and tricyclic antidepressants.

Method: A review of the literature of two centuries finds descriptions of severe mood disorders, either depression or mania or circular, defined as ‘melancholia.’ In the 1980 diagnostic revision (DSM‐III), melancholia was relegated to a features specifier only.

Results: DSM classification criteria develop heterogeneous patient samples that are neither guides to prognosis nor to treatment response, and confound studies of pathophysiology. Within the large population of mood disorders, a syndrome of melancholia is identifiable by specific behaviors, vegetative signs, and validated by neuroendocrine abnormalities (cortisolemia). Populations so identified are clinically homogeneous and have improved treatment responses. Patients meeting criteria for melancholia are now identified as psychotic depressed, geriatric depressed, postpartum psychosis, and pharmacotherapy resistant.

Conclusion: The review supports the establishment of melancholia by empirically derived criteria rather than by a checklist is an alternative to the major depression choice and offers an improved model for psychiatric classification.
Defining melancholia: the primacy of psychomotor disturbance
Authors: Parker G.
Published: January 2007

Objective:  To argue that melancholia is a categorically distinct depressive condition, able to be differentiated from other depressive conditions by a neuropathological marker [observable psychomotor disturbance (PMD)] and having a differential response to various antidepressant treatments.

Method:  The above statements are addressed by review of a wide body of research, which identified observable PMD as the cardinal marker of melancholia and developed the CORE measure as a strategy for assessing PMD and its severity. Properties of the CORE measure, including reliability, validity and treatment prediction, are overviewed.

Results:  A case is made for defining melancholia and a strategy for establishing its probability.

Conclusion:  Melancholia is positioned as a categorical entity capable of being circumscribed by its cardinal feature of PMD.
Melancholia agitata and mixed depression
Authors: Koukopoulos A. , Sani G. , Koukopoulos A. E. , Manfredi G. , Pacchiarotti I. , Girardi P.
Published: January 2007

Objective:  The diagnostic entity of major depressive episode includes both simple and agitated or mixed depression. Mixed depression is characterized by a full depressive episode with several symptoms of excitatory nature. Mixed depressions worsen if treated with antidepressants.

Method:  We have reviewed the clinical charts of the 2141 patients treated at the Centro Lucio Bini of Rome from January 1999 to June 2006. These patients were diagnosed according to DSM‐IV criteria. Research diagnostic criteria were applied for agitated depression with motor agitation and Author's diagnostic criteria for agitated depression without motor agitation.

Results:  One thousand and twenty‐six patients had a depressive episode as index episode. Three hundred and forty six (33%) were mixed depressive states. One hundred and thirty eight (44%) of them were spontaneous; in 173 cases, the onset of the mixed depression was associated with antidepressants.

Conclusion:  Psychic and motor agitation are considered equally important for the definition of agitated depression. Treating agitated depression with antidepressants worsens the clinical picture. The use of Electroconvulsive Therapy (ECT), neuroleptics and anticonvulsants are recommended. The term Melancholia Agitata is proposed for agitated (mixed) depression.
Epidemiology of subtypes of depression
Authors: Kessing L. V.
Published: January 2007

Objective:  There is a general clinical impression that depression differs qualitatively from non‐depressive conditions, and that it can be identified as a categorical entity. In contrast, epidemiological studies support the view that depression is dynamic in nature and develops on a continuous scale. The present article reviews selected epidemiological studies of depressive subtypes.

Method:  A selective review.

Results:  Prior studies have found no clear differences in clinical presentation or long‐term outcome between patients with melancholic and with neurotic/reactive depression. In addition, recent studies suggest that there is no clear demarcation between mild, moderate, and severe depression, pointing toward a continuity rather than categories of illness. For the individual patient, depressive symptoms seem to change over time, fulfilling criteria for major depression, minor depression, dysthymia, and subsyndromal states; the association between stressful life events and depression appears to diminish with the number of depressive episodes. Finally, recent genetic findings are congruent with a model indicating that the majority of depressions develop in the interplay between genes and stressful experiences, whereas ‘reactive’ depressions and ‘endogenous’ depressions apparently exist at a lower prevalence.

Conclusion:  Further longitudinal, analytical, and genetic epidemiologic studies are needed to reveal which conditions are mild and transient, and which may be precursors of more severe and substantial illness such as melancholia.
Does dopamine dysfunction drive depression?
Authors: Malhi G. S. , Berk M.
Published: January 2007

Objective:  To examine the evidence that dopamine (DA) dysfunction contributes to melancholic depression.

Method:  Database (EMBASE, PsychLit and MEDLINE) searches using relevant key words were conducted and citations were scrutinized.

Results:  In this paper, we assume that the definition of melancholia is contingent upon the presence of psychomotor disturbance (PMD). In melancholic depression PMD comprises both a cognitive and motor component and DA is found to be important in both. DA neurotransmission modulates cognition in particular in attention, adaptation and motivational processes and has a pivotal role in motor function.

Conclusion:  DA is a credible aetiological candidate for the PMD in melancholic depression. However, melancholia needs first to be characterized both clinically and in terms of its pathophysiology. In this regard, illnesses such as bipolar depression and Parkinson's disease warrant consideration as they provide suitable models of both the cognitive and motor aspects of PMD, and hold the necessary markers to better define melancholia.
Treatment response in melancholia
Authors: Brown W. A.
Published: January 2007

Objective:  Ascertain the response to specific depression treatments in melancholic and non‐melancholic depressed patients.

Method:  Literature review focusing on studies addressing symptoms, diagnostic profiles, severity and other predictors of outcome with antidepressant medication, electroconvulsive therapy (ECT), psychotherapy and placebo.

Results:  Patients with melancholia do not consistently differ from those with non‐melancholic depression in their response to antidepressants and ECT, but patients with melancholia show a significantly lower rate of placebo response. Depressed patients classified as severely ill‐many of whom are melancholic‐likewise do not differ from the less severely ill in response to antidepressants but do have a consistently lower placebo response rate. The little available data from psychotherapy studies also consistently show that melancholic and severely depressed patients are less likely than the more mildly depressed to improve with various types of psychotherapy. Depressed patients with increased pituitary‐adrenocortical activity‐most of whom are melancholic‐show a similar pattern of treatment response: they do well with ECT and antidepressants and poorly with placebo and psychotherapies.

Conclusion:  The research data, in the aggregate, suggest that the presence of melancholia predicts a poor response to psychotherapy and placebo and a relatively good response to antidepressants and ECT.
Pharmacological treatment of negative symptoms of schizophrenia: therapeutic opportunity or Cul‐de‐sac?
Authors: Buckley P. F. , Stahl S. M.
Published: January 2007

Objective: Negative symptoms of schizophrenia are debilitating and they contribute to poor outcome in schizophrenia. Initial enthusiasm that second‐generation antipsychotics would prove to be powerful agents to improve negative symptoms has given way to relative pessimism that the effects of current pharmacological treatments are at best modest.

Method: A review of the current ‘state‐of‐play’ of pharmacological treatments for negative symptoms in schizophrenia.

Results: Treatment results to date have been largely disappointing. The evidence for efficacy of second‐generation antipsychotics is reviewed.

Conclusion: The measurement and treatment trials methodology for the evaluation of negative symptoms need additional refinement before therapeutic optimism that better treatments for negative symptoms can be realized.
Does self‐weighting of items enhance the performance of an oral health‐related quality of life questionnaire?
Authors: Locker David , Berka Eva , Jokovic Aleksandra , Tompson Bryan
Published: January 2007

Abstract –  Objectives:  To determine if self‐weighting of the items in an oral health‐related quality of life questionnaire improves its psychometric properties.

Methods:  The Surgical Orthodontic Outcome Questionnaire (SOOQ) was designed to assess the oral health‐related quality of life of individuals before and after corrective surgery. Each of its 33 ‘items’ consists of two questions: a question concerning the frequency with which a given functional or psychosocial problem had been experienced and a ‘weighting’ question which asked about how much the individual was bothered by that problem. The questionnaire was completed by three groups of individuals: (i) pretreatment; (ii) immediate (i.e. 2–6 months) postsurgery and (iii) postsurgery (i.e. more than 2 years after surgery). Unweighted scale scores were obtained by summing the response codes to the frequency question and weighted scores by summing the products of the frequency and bother questions. These scores were calculated for the full questionnaire and a short form consisting of 15 items. The discriminative and correlational construct validity of these scores was compared along with internal consistency reliability. The sensitivity to change and longitudinal construct validity of unweighted and weighted scores was assessed in a simulated evaluative study in which pretreatment and postsurgery subjects were paired.

Results:  For both the long and short forms of the questionnaire, unweighted and weighted scores discriminated between the groups enrolled in the study. Correlations with a general health rating were similar, as were Cronbach's alpha values and test–retest reliabilities. The simulated evaluative study suggested no differences in sensitivity to change or longitudinal construct validity. When subscale scores were examined, there was a suggestion that weighting improved their reliability.

Conclusions:  Self‐weighting of items did not substantially improve the performance of the SOOQ. Domain weights should be developed and tested to determine if they have an effect on its properties.
Developing a short form of Oral Health Impact Profile (OHIP) for dental aesthetics: OHIP‐aesthetic
Authors: Wong Anthony H. H. , Cheung C. S. , McGrath Colman
Published: January 2007

Abstract –  Objectives:  To develop and evaluate shortened forms of the Oral Health Impact Profile (OHIP) for discriminating dental aesthetics problems and evaluating dental aesthetic outcomes.

Methods:  Eighty‐seven subjects self‐completed the 49‐item OHIP at baseline and 63 at follow up (8 weeks later), with the intervention of applying an array of tooth‐whitening products. Expert‐based approach and regression analysis (on baseline data) were undertaken to derive two subset questionnaires (OHIP‐conceptual and OHIP‐regression). Their discriminatory ability for dental aesthetics and their responsiveness to tooth whitening were compared with the original OHIP‐49, Slade's OHIP‐14 and a Chinese short‐form version of OHIP.

Results:  The measures developed were strongly associated with self‐rating of dental aesthetics (P < 0.001) unlike OHIP‐49 (P = 0.03) or other OHIP short forms (P > 0.05). The measures were also reliable (Cronbach's alpha 0.86) and comparable with the other OHIP forms. In terms of effect size, OHIP‐conceptual was more effective in measuring changes than the one based on the regression analysis, the original OHIP‐49, OHIP‐14 and the Chinese version of the short‐form OHIP. It also exhibited a less susceptibility to floor effects than other OHIP forms.

Conclusion:  A modified short form of the OHIP derived (OHIP‐conceptual) was the most favorable in discriminating dental aesthetics, was reliable and most sensitive to the dental aesthetics intervention – tooth whitening.
Effect of melatonin on cholesterol absorption in rats
Authors: Hussain Saad Abdul‐Rehman
Published: January 2007

Abstract: This study evaluated the influence of melatonin on cholesterol absorption in rats fed on high cholesterol diet (HCD). HCD induced a remarkable increase in hepatic and plasma total cholesterol, plasma very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, a decrease in high density lipoprotein (HDL) cholesterol and an elevation in triacylglyceride (TG) levels in plasma and in the liver. Melatonin suspension (10 mg/kg), specially prepared for this purpose, cholestyramine (230 mg/kg) and ezetimibe (145 μg/kg) were administered orally to the rats fed HCD for 30 days. Melatonin significantly reduced cholesterol absorption in rats fed on HCD and caused significant decreases in total cholesterol, TG, VLDL‐ and LDL‐cholesterol in the plasma and contents of cholesterol and TG in the liver. The level of HDL cholesterol was significantly increased after melatonin. These results suggested that inhibition of cholesterol absorption caused by melatonin could be a mechanism contributing to the positive changes in plasma cholesterol, lipoprotein profile and the lipid contents in the liver.
Salmonella Trafficking is Defined by Continuous Dynamic Interactions with the Endolysosomal System
Authors: Drecktrah Dan , Knodler Leigh A. , Howe Dale , Steele‐Mortimer Olivia
Published: January 2007

Following invasion of non‐phagocytic host cells, Salmonella enterica survives and replicates within a phagosome‐like compartment known as the Salmonella‐containing vacuole (SCV). It is now well established that SCV biogenesis, like phagosome biogenesis, involves sequential interactions with the endocytic pathway. However, Salmonella is believed to limit these interactions and, in particular, to avoid fusion of terminal lysosomes with the SCV. In this study, we reassessed this process using a high‐resolution live‐cell imaging approach and found an unanticipated level of interaction between the SCV and the endocytic pathway. Direct interactions, in which late endosomal/lysosomal content was transferred to SCVs, were detected within 30 min of invasion and continued for several hours. Mechanistically, these interactions were very similar to phagosome–lysosome fusion because they were accompanied by rapid acidification of the SCV, could be blocked by chemical perturbation of microtubules or vacuolar acidification and involved the small
GTPase Rab7. In comparison with vacuoles containing internalized Escherichia coli or heat‐killed Salmonella, SCVs did show some delay of fusion and acidification, although, this appeared to be independent of either type III secretion system. These results provide compelling evidence that inhibition of SCV–lysosome fusion is not the major determinant in establishment of the Salmonella replicative niche in epithelial cells.
Intrinsically active variants of all human p38 isoforms
Authors: Avitzour Michal , Diskin Ron , Raboy Bilha , Askari Nadav , Engelberg David , Livnah Oded
Published: January 2007

The p38 mitogen‐activated protein kinases are activated in response to various extracellular signals in eukaryotic cells and play a critical role in the cellular responses to these signals. The four mammalian isoforms (p38α, p38β, p38γ, and p38δ) are coexpressed and coactivated in the same cells. The exact role of each p38 isoform has not been entirely identified, in part due to the inability to activate each member individually. This could be resolved by the use of intrinsically active mutants. Based on previous studies on yeast p38/Hog1 [Bell M, Capone R, Pashtan I, Levitzki A & Engelberg D (2001) J Biol Chem276, 25351–2538] and human p38α[Diskin R, Askari N, Capone R, Engelberg D & Livnah O (2004) J Biol Chem279, 47040–47049] we have generated intrinsically active p38β, p38γ and p38δ mutants. In addition, we have identified a new activating mutation site in p38α. Most of the activating mutations are located in the L16 loop, in which conformational changes were shown to induce activation. We show that these changes impose substantial autophosphorylation activity, providing a mechanistic explanation for the intrinsic activity of the mutants. The new active variants maintain specificity towards substrates and inhibitors similar to that of the parental wild‐type proteins, and are phosphorylated by mitogen‐activated protein kinase kinase 6, their upstream activator. Thus, we have completed the development of a series of intrinsically active mutants of all p38 isoforms. These active variants could now become powerful tools for the elucidating the activation mechanism and specific biological roles of each p38 isoform.
Fermentative lifestyle in yeasts belonging to the Saccharomyces complex
Authors: Merico Annamaria , Sulo Pavol , Piškur Jure , Compagno Concetta
Published: January 2007

The yeast Saccharomyces cerevisiae is characterized by its ability to: (a) degrade glucose or fructose to ethanol, even in the presence of oxygen (Crabtree effect); (b) grow in the absence of oxygen; and (c) generate respiratory‐deficient mitochondrial mutants, so‐called petites. How unique are these properties among yeasts in the Saccharomyces clade, and what is their origin? Recent progress in genome sequencing has elucidated the phylogenetic relationships among yeasts in the Saccharomyces complex, providing a framework for the understanding of the evolutionary history of several modern traits. In this study, we analyzed over 40 yeasts that reflect over 150 million years of evolutionary history for their ability to ferment, grow in the absence of oxygen, and generate petites. A great majority of isolates exhibited good fermentation ability, suggesting that this trait could already be an intrinsic property of the progenitor yeast. We found that lineages that underwent the whole‐genome duplication, in general, exhibit a fermentative lifestyle, the Crabtree effect, and the ability to grow without oxygen, and can generate stable petite mutants. Some of the pre‐genome duplication lineages also exhibit some of these traits, but a majority of the tested species are petite‐negative, and show a reduced Crabtree effect and a reduced ability to grow in the absence of oxygen. It could be that the ability to accumulate ethanol in the presence of oxygen, a gradual independence from oxygen and/or the ability to generate petites were developed later in several lineages. However, these traits have been combined and developed to perfection only in the lineage that underwent the whole‐genome duplication and led to the modern Saccharomyces cerevisiae yeast.
Observation of a chaotic multioscillatory metabolic attractor by real‐time monitoring of a yeast continuous culture
Authors: Roussel Marc R. , Lloyd David
Published: January 2007

We monitored a continuous culture of the yeastSaccharomyces cerevisiaeby membrane‐inlet mass spectrometry. This technique allows very rapid simultaneous measurements (one point every 12 s) of several dissolved gases. During our experiment, the culture exhibited a multioscillatory mode in which the dissolved oxygen and carbon dioxide records displayed periodicities of 13 h, 36 min and 4 min. The 36‐ and 4‐min modes were not visible at all times, but returned at regular intervals during the 13‐h cycle. The 4‐min mode, which has not previously been described in continuous culture, can also be seen when the culture displays simpler oscillatory behavior. The data can be used to visualize a metabolic attractor of this system, i.e. the set of dissolved gas concentrations which are consistent with the multioscillatory state. Computation of the leading Lyapunov exponent reveals the dynamics on this attractor to be chaotic.
Identification and expression analysis of a MYB family transcription factor in the parasitic plant Orobanche ramosa
Authors: González‐Verdejo C.I. , Dita M.A. , Di Pietro A. , Moreno Ma.T. , Barandiarán X. , Rubiales D. , González‐Melendi P. , Pérez‐de‐Luque A.
Published: January 2007

MYB proteins are transcription factors (TFs) involved in the regulation of developmental processes in eukaryotes. A number of MYB genes have been identified from plants, but they have not been studied in parasitic plants. In this work, a member of the R2R3 MYB family of TFs was isolated from a complementary DNA library representing different developmental stages of the parasitic plant Orobanche ramosa. The pattern of expression of the gene was studied by in situ hybridisation. Alignment of the deduced Or‐MYB1 protein with members of the MYB family showed the highest overall identity with MYB.Ph3 from petunia (Petunia hybrida), NtMYBAS1/S2 from tobacco (Nicotiana tabacum) and AtMYB101 from Arabidopsis thaliana. Amino acid sequence comparisons of DNA‐binding domains showed that Or‐MYB1 protein forms a closely related group with these proteins. Transcripts of Or‐MYB1 were detected during all the developmental stages analysed, and in situ hybridisation showed that the expression was restricted to the parenchymatic cells proximal to the vascular vessels. These findings are consistent with a role of Or‐MYB1 during early stages of development of O. ramosa, probably through the phenylpropanoid pathway.
Diversity of the rodent communities in the Turan Desert region
Authors: NERONOV Valery M. , KHLYAP Ludmila A. , WARSHAVSKY Andrey A.
Published: January 2007

We assessed the diversity of rodent communities in the deserts of Russia, Kazakhstan, and Central Asia using geographic information system technology. There are 66 species of rodents, belonging to eight faunistic complexes, inhabiting this area. We discuss the geographical changes occurring in taxonomic and zoogeographic diversity at both species and community levels. Communities of gerbils and jerboas dominate in the Turan Desert region (66% of the area). Steppe communities of susliks penetrate the deserts from the north. Farming in deserts causes the replacement of native rodent communities with mouse communities or completely eradicates rodents in their main habitats.
Ventilatory control in humans: constraints and limitations
Authors: Ward Susan A.
Published: January 2007

Below the lactate threshold (θL), ventilation
responds in close proportion to CO2 output
to regulate arterial partial pressure of CO2
. While ventilatory control models have traditionally included proportional feedback (central and carotid chemosensory) and feedforward (central and peripheral neurogenic) elements, the mechanisms involved remain unclear. Regardless, putative control schemes have to accommodate the close dynamic ‘coupling’ between
and
. Above θL,
is driven down to constrain the fall of arterial pH by a compensatory hyperventilation, probably of carotid body origin. When
requirements are high (as in highly fit endurance athletes),
can attain limiting proportions. Not only does this impair gas exchange at these work rates, but there may be an associated high metabolic cost for generation of respiratory muscle power, which may be sufficient to divert a fraction of the cardiac output away from the muscles of locomotion to the respiratory muscles, further compromising exercise tolerance.
Effects of indomethacin on systemic and renal haemodynamics in conscious lambs
Authors: Ebenezar Kesavarao Kumar , Ghane Fatemah Sharbaf , Smith Francine Gabriel
Published: January 2007

Both prostaglandins (PGs) PGE2 and PGI2 can act as renal vasodilators, these effects being exacerbated when the renin–angiotensin system is activated. Therefore, we hypothesized that PGs would play a more predominant role in modulating renal haemodynamics in the newborn period, when the renin–angiotensin system is activated. To this end, the role of endogenously produced PGs in modulating systemic and renal haemodynamics was investigated in two groups of conscious lambs aged ∼1 and ∼6 weeks. Arterial pressure, venous pressure and renal blood flow were measured for 5 min before (control) and for 20 min after intravenous injection of vehicle (experiment 1). Twenty‐four hours later, this protocol was repeated with intravenous injection of the non‐selective cyclo‐oxygenase inhibitor indomethacin (1 mg kg−1, experiment 2). Heart rate was calculated from the systolic peak of the arterial pressure waveform, and renal vascular resistance (RVR) was calculated from the measured variables. In response to indomethacin but not vehicle, in both age groups of lambs there was an increase in mean arterial pressure and pulse interval, as well as a marked increase in RVR. These responses to indomethacin were, however, transient, with baseline levels being resumed within minutes. Although the hypothesis that PGs play a greater role in modulating renal haemodynamics early in life is not supported, these data do provide evidence that endogenously produced PGs modulate systemic and renal haemodynamics during postnatal maturation. It is apparent, however, that other vasoactive factors must be rapidly recruited in order to buffer the circulatory responses to removal of vasodilatory PGs in the developing newborn.
Pathways involved in gut mucosal barrier dysfunction induced in adult rats by maternal deprivation: corticotrophin‐releasing factor and nerve growth factor interplay
Authors: Barreau Frederick , Cartier Christel , Leveque Mathilde , Ferrier Laurent , Moriez Raphael , Laroute Valerie , Rosztoczy Andras , Fioramonti Jean , Bueno Lionel
Published: January 2007

Neonatal maternal deprivation (NMD) increases gut paracellular permeability (GPP) through mast cells and nerve growth factor (NGF), and modifies corticotrophin‐releasing factor (CRF) and corticosterone levels. CRF, corticosterone and mast cells are involved in stress‐induced mucosal barrier impairment. Consequently, this study aimed to specify whether corticosteronaemia and colonic expression of both preproCRF and CRF are modified by NMD, and to determine if altered expression may participate in the elevated GPP in connection with NGF and mast cells. Male Wistar rat pups were either separated from postnatal days 2–14, or left undisturbed with their dam. At 12 weeks of age, adult rats were treated with mifepristone (an antagonist of corticoid receptors), α‐helical CRF(9‐41) (a non‐specific CRF receptor antagonist), or SSR‐125543 (CRF‐R1 receptor antagonist). We also determined corticosteronaemia and both colonic preproCRF and CRF expression. Then, control rats were treated by CRF, doxantrazole (mast cell stabilizer), BRX‐537A (a mast cell activator) and anti‐NGF antibody. NMD did not modify colonic CRF level but increased colonic preproCRF expression and corticosteronaemia. Peripheral CRF, via CRF‐R1 receptor, but not corticosterone, was involved in the elevated GPP observed in these rats, through a mast‐cell‐mediated mechanism, since the increase of GPP induced by exogenous CRF was abolished by doxantrazole. Anti‐NGF antibody treatment also reduced the elevated GPP induced by CRF or BRX‐537A. CRF acts through CRF‐R1 receptors to stimulate NGF release from mast cells, which participates in the elevated GPP observed in NMD adult rats. This suggests that early traumatic experience induced neuro‐endocrine dysfunction, involved in alterations of gut mucosal barrier.
Robust correlations between action potential duration and the properties of synaptic connections in layer 4 interneurones in neocortical slices from juvenile rats and adult rat and cat
Authors: Ali Afia B. , Bannister A. Peter , Thomson Alex M.
Published: January 2007

Many studies of cortical interneurones use immature rodent tissue, while many recordings in vivo are made in adult cats. To determine the extent to which interneuronal circuitry studied with one approach can transfer to another, we compared layer 4 interneurones and their local connections across two age groups and two species and with similar connections in layers 3 and 5, using two common recording techniques: dual whole cell recordings at 20°C and dual sharp electrode recordings at 35°C. In each group, a range of morphological and electrophysiological characteristics was observed. In all groups, however, positive correlations were found between the width of the action potential and rise times and widths at half‐amplitude of EPSPs and IPSPs and the EPSP paired pulse ratio. Multipolar interneurones with narrow spikes generated the fastest IPSPs in pyramidal cells and received the briefest, most strongly depressing EPSPs, while bitufted interneurones with broader spikes and adapting and burst firing patterns activated the broadest IPSPs and received the slowest, most strongly facilitating/augmenting EPSPs. Correlations were similar in all groups, with no significant differences between adult rat and cat, or between layers, but events were four times slower in juveniles at 20°C. Comparisons with previous studies indicate that this is due in part to age, but in large part to temperature. Studies in adults were extended with detailed analysis of synaptic dynamics, which appeared to decay more rapidly than at juvenile connections. EPSPs exhibited the complexity in time course of facilitation, augmentation and depression previously described in other adult neocortical connections. That is, the time course of recovery from facilitation or depression rarely followed a simple smooth exponential decay. Facilitation and depression were not always maximal at the shortest interspike intervals, and recovery was often interrupted by peaks and troughs in mean EPSP amplitude with a periodicity around 80 Hz.
Dehydration increases L‐type Ca2+ current in rat supraoptic neurons
Authors: Zhang Wenbo , Star Blanc , Rajapaksha W. R. A. K. J. S. , Fisher Thomas E.
Published: January 2007

The magnocellular neurosecretory cells of the hypothalamus (MNCs) regulate water balance by releasing vasopressin (VP) and oxytocin (OT) as a function of plasma osmolality. Release is determined largely by the rate and pattern of MNC firing, but sustained increases in osmolality also produce structural adaptations, such as cellular hypertrophy, that may be necessary for maintaining high levels of neuropeptide release. Since increases in Ca2+ current could enhance exocytotic secretion, influence MNC firing patterns, and activate gene transcription and translation, we tested whether Ca2+ currents in MNCs acutely isolated from the supraoptic nucleus (SON) of the hypothalamus are altered by 16–24 h of water deprivation. A comparison of whole‐cell patch‐clamp recordings demonstrated that dehydration causes a significant increase in the amplitude of current sensitive to the L‐type Ca2+ channel blocker nifedipine (from –56 ± 6 to –99 ± 10 pA; P < 0.001) with no apparent change in other components of Ca2+ current. Post‐recording immunocytochemical identification showed that this increase in current occurred in both OT‐ and VP‐releasing MNCs. Radioligand binding studies of tissue from the SON showed there is also an increase in the density of binding sites for an L‐type Ca2+ channel ligand (from 51.5 ± 4.8 to 68.1 ± 4.1 fmol (mg protein)−1; P < 0.05), suggesting that there was an increase in the number of L‐type channels on the plasma membrane of the MNCs or some other cell type in the SON. There were no changes in the measured number of binding sites for an N‐type Ca2+ channel ligand. Dehydration was not associated with changes in the levels of mRNA coding for Ca2+ channel α1 subunits. These data are consistent with the hypothesis that a selective increase of L‐type Ca2+ current may contribute to the adaptation that occurs in the MNCs during dehydration.
Measuring the Stokes polarization parameters
Authors: Schaefer Beth , Collett Edward , Smyth Robert , Barrett Daniel , Fraher Beth
Published: January 2007

The Stokes formulation for representing polarized light is discussed along with the classical measurement method for determining the Stokes polarization parameters. The limitations of this method are noted, and we consider the rotating quarter-waveplate method, which avoids the limitations of the classical method and allows a curve fitting algorithm to be used to determine the Stokes parameters. The quarter-waveplate method is attractive because of its accuracy and simplicity and can be implemented in an undergraduate or graduate optics course with a minimum amount of equipment.
The physics of the space elevator
Authors: Aravind P. K.
Published: January 2007

A space elevator is a tall tower rising from a point on the Earth’s equator to a height well above a geostationary orbit, where it terminates in a counterweight. Although the concept is more than a century old, it was only with the discovery of carbon nanotubes that it began to receive serious scientific attention. NASA commissioned a study of the space elevator in the late 1990s that examined the feasibility of such a structure and explored many of its applications. I explain the basic mechanical principles underlying the construction of a space elevator and discuss several of its applications: the transport of payload into space and the launching of spacecraft on voyages to other planets.
Comparison of ocean-acoustic horizontal coherence predicted by path-integral approximations and parabolic-equation simulation results
Authors: Vera Michael D.
Published: January 2007

A line-integral approximation to the acoustic path integral has been used to generate predictions for the characteristic length scale of horizontal, cross-range coherence in long-range ocean-acoustic propagation. These estimates utilize a single range-independent sound-speed profile and the mean variance, as a function of depth, of fractional sound-speed perturbations due to internal waves. The length scales predicted by the integral approximation have been compared to the values generated by parabolic-equation simulations through multiple realizations of Garrett-Munk internal waves. One of the simulation environments approximates the Slice89 experiment; transmissions from a 250-Hz source were simulated in a deep-water transect to a maximum range of 1000km. The second environment corresponds to one of the propagation paths in the North Pacific Acoustic Laboratory (NPAL) experiment. The source in this experiment was bottom-mounted near Kauai, Hawaii and the relevant receiver consisted of five vertical line arrays oriented transverse to the propagation path with cross-range separations ranging from approximately 500 to 3500m. The receiver was at a range of 3889.8km from the source. The predicted length scales are consistently shorter than the parabolic-equation results by 30%–80%, depending on the range and environment examined.
Experimental study of A0 and T1 modes of the concert harp
Authors: Le Carrou J-L. , Gautier F. , Foltête E.
Published: January 2007

String instruments are usually composed of a set of strings, a soundboard, and a soundbox with sound holes, which is generally designed to increase the sound level by using the acoustic resonances of the cavity. In the case of the harp, the soundbox and especially the sound holes are primarily designed to allow access to the strings for their mounting. An experimental modal analysis, associated to measurements of the acoustic velocity in the holes, shows the importance of two particular modes labeled A0 and T1 as it was done for the guitar and the violin. Their mode shapes involve coupled motions of the soundboard’s bending and of the oscillations of the air pistons located in the sound holes. The A0 mode is found above the frequency of the lowest acoustically significant structural mode T1. Thus, the instrument does not really take advantage of the soundbox resonance to increase its radiated sound in low frequencies. However, contribution of mode A0 is clearly visible in the response of the instrument, confirming the importance of the coupling between the soundboard and the cavity.
Local feedback control of light honeycomb panels
Authors: Hong Chinsuk , Elliott Stephen J.
Published: January 2007

This paper summarizes theoretical and experimental work on the feedback control of sound radiation from honeycomb panels using piezoceramic actuators. It is motivated by the problem of sound transmission in aircraft, specifically the active control of trim panels. Trim panels are generally honeycomb structures designed to meet the design requirement of low weight and high stiffness. They are resiliently mounted to the fuselage for the passive reduction of noise transmission. Local coupling of the closely spaced sensor and actuator was observed experimentally and modeled using a single degree of freedom system. The effect of the local coupling was to roll off the response between the actuator and sensor at high frequencies, so that a feedback control system can have high gain margins. Unfortunately, only relatively poor global performance is then achieved because of localization of reduction around the actuator. This localization prompts the investigation of a multichannel active control system. Globalized reduction was predicted using a model of 12-channel direct velocity feedback control. The multichannel system, however, does not appear to yield a significant improvement in the performance because of decreased gain margin.
Effects of masking noise on vowel and sibilant contrasts in normal-hearing speakers and postlingually deafened cochlear implant users
Authors: Perkell Joseph S. , Denny Margaret , Lane Harlan , Guenther Frank , Matthies Melanie L. , Tiede Mark , Vick Jennell , Zandipour Majid , Burton Ellen
Published: January 2007

The role of auditory feedback in speech production was investigated by examining speakers’ phonemic contrasts produced under increases in the noise to signal ratio (N/S). Seven cochlear implant users and seven normal-hearing controls pronounced utterances containing the vowels /i/, /u/, /ε/ and /æ/ and the sibilants /s/ and /ʃ/ while hearing their speech mixed with noise at seven equally spaced levels between their thresholds of detection and discomfort. Speakers’ average vowel duration and SPL generally rose with increasing N/S. Average vowel contrast was initially flat or rising; at higher N/S levels, it fell. A contrast increase is interpreted as reflecting speakers’ attempts to maintain clarity under degraded acoustic transmission conditions. As N/S increased, speakers could detect the extent of their phonemic contrasts less effectively, and the competing influence of economy of effort led to contrast decrements. The sibilant contrast was more vulnerable to noise; it decreased over the entire range of increasing N/S for controls and was variable for implant users. The results are interpreted as reflecting the combined influences of a clarity constraint, economy of effort and the effect of masking on achieving auditory phonemic goals—with implant users less able to increase contrasts in noise than controls.
The effect of fundamental frequency on the brightness dimension of timbre
Authors: Marozeau Jeremy , de Cheveigné Alain
Published: January 2007

The dependency of the brightness dimension of timbre on fundamental frequency (F0) was examined experimentally. Subjects compared the timbres of 24 synthetic stimuli, produced by the combination of six values of spectral centroid to obtain different values of expected brightness, and four F0’s, ranging over 18 semitones. Subjects were instructed to ignore pitch differences. Dissimilarity scores were analyzed by both ANOVA and multidimensional scaling (MDS). Results show that timbres can be compared between stimuli with different F0’s over the range tested, and that differences in F0 affect timbre dissimilarity in two ways. First, dissimilarity scores reveal a term proportional to F0 difference that shows up in the MDS solution as a dimension correlated with F0 and orthogonal to other timbre dimensions. Second, F0 affects systematically the timbre dimension (brightness) correlated with spectral centroid. Interestingly, both terms covaried with differences in F0 rather than chroma or consonance. The first term probably corresponds to pitch. The second can be eliminated if the formula for spectral centroid is modified by introducing a corrective factor dependent on F0.
Excitation of soft porous frame resonances and evaluation of rigidity coefficients
Authors: Allard Jean F. , Brouard Bruno , Atalla Noureddine , Ghinet Sebastian
Published: January 2007

Recent works have been performed concerning the guided elastic waves in soft porous elastic frames and the related normal displacement of the surface generated by a mechanical excitation. In this work, the mechanical excitation is replaced by a monopole acoustic field in air above the porous structure. Two cases are considered: a frame bonded on a rigid impervious layer and a free frame. The normal and the radial velocity induced by the monopole field at the surface of the frame is predicted with the Biot theory and the Sommerfeld representation of the monopole field. Measurements are performed with a laser vibrometer on a urethane foam. It is shown that the characterization of the excited modes can lead to an evaluation of the rigidity coefficients of the frames at acoustical frequencies.