112 research outputs found

    From little things, big things grow: trends and fads in 110 years of Australian ornithology

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    Publishing histories can reveal changes in ornithological effort, focus or direction through time. This study presents a bibliometric content analysis of Emu (1901–2011) which revealed 115 trends (long-term changes in publication over time) and 18 fads (temporary increases in publication activity) from the classification of 9,039 articles using 128 codes organised into eight categories (author gender, author affiliation, article type, subject, main focus, main method, geographical scale and geographical location). Across 110 years, private authorship declined, while publications involving universities and multiple institutions increased; from 1960, female authorship increased. Over time, question-driven studies and incidental observations increased and decreased in frequency, respectively. Single species and ‘taxonomic group’ subjects increased while studies of birds at specific places decreased. The focus of articles shifted from species distribution and activities of the host organisation to breeding, foraging and other biological/ecological topics. Site- and Australian-continental-scales slightly decreased over time; non-Australian studies increased from the 1970s. A wide variety of fads occurred (e.g. articles on bird distribution, 1942–1951, and using museum specimens, 1906–1913) though the occurrence of fads decreased over time. Changes over time are correlated with technological, theoretical, social and institutional changes, and suggest ornithological priorities, like those of other scientific disciplines, are temporally labil

    Fully adaptive multiresolution schemes for strongly degenerate parabolic equations with discontinuous flux

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    A fully adaptive finite volume multiresolution scheme for one-dimensional strongly degenerate parabolic equations with discontinuous flux is presented. The numerical scheme is based on a finite volume discretization using the Engquist--Osher approximation for the flux and explicit time--stepping. An adaptivemultiresolution scheme with cell averages is then used to speed up CPU time and meet memory requirements. A particular feature of our scheme is the storage of the multiresolution representation of the solution in a dynamic graded tree, for the sake of data compression and to facilitate navigation. Applications to traffic flow with driver reaction and a clarifier--thickener model illustrate the efficiency of this method

    Demographic and clinical determinants of neck pain in idiopathic cervical dystonia.

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    Cervical dystonia is associated with neck pain in a significant proportion of cases, but the mechanisms underlying pain are largely unknown. In this exploratory study, we compared demographic and clinical variables in cervical dystonia patients with and without neck pain from the Italian Dystonia Registry. Univariable and multivariable logistic regression analysis indicated a higher frequency of sensory trick and a lower educational level among patients with pain

    PD-168077, a selective dopamine D4 receptor agonist, induces penile erection when injected into the paraventricular nucleus of male rats

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    The effect of PD-168077 (N-methyl-4-(2-cyanophenyl)piperazynil-3-methylbenzamide maleate), a selective D4 dopamine receptor agonist, injected into the paraventricular nucleus of the hypothalamus on penile erection was studied in male rats. PD-168077 (1-200 ng) induced penile erection in a dose-dependent manner. The minimal effective dose was 50 ng, while the maximal response was found with 200 ng of the compound, which increased penile erection episodes from 0.3+/-0.03 to 1.7+/-0.21. The proerectile effect of PD-168077 was reduced almost completely by L-745,870 (3-(4-[chlorophenyl]piperazin-1-yl)-methyl-1H-pyrrolo[2,3-B]pyridine trihydrochloride), a selective D4 dopamine receptor antagonist, (1 microg) given into the paraventricular nucleus before the D4 dopamine agonist, and by other nonselective dopamine receptor antagonists, such as haloperidol (1 microg) and clozapine (1 microg), which block all dopamine receptor subtypes. The pro-erectile effect of PD-168077 was also reduced by the NO synthase inhibitor NG-nitro-L-arginine methylester (25 microg), but not by the oxytocin receptor antagonist d(CH2)5Tyr(Me)2-Orn8-vasotocin (1 microg), when given into the paraventricular nucleus. In spite of its inability to prevent the pro-erectile effect of PD-168077 when given in the paraventricular nucleus, d(CH2)5Tyr(Me)2-Orn8-vasotocin (1 microg) reduced almost completely PD-168077-induced penile erection when given into the lateral ventricles. The present results show that D4 dopamine receptors present in the paraventricular nucleus may influence penile erection by modulating the activity of paraventricular oxytocinergic neurons mediating erectile function

    Extracellular excitatory amino acids increase in the paraventricular nucleus of male rats during sexual activity: main role of N-methyl-d-aspartic acid receptors in erectile function

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    The concentrations of glutamic and aspartic acids were measured in the dialysate obtained with vertical microdialysis probes implanted into the paraventricular nucleus of the hypothalamus of sexually potent male rats during sexual activity. Animals showed noncontact erections when put in the presence of, and copulated with, a receptive (ovarietomized oestrogen- and progesterone-primed) female rat. The concentrations of glutamic and aspartic acids in the paraventricular dialysate increased by 37 and 80%, respectively, above baseline values during exposure to the receptive female rat and by 55 and 127%, respectively, during copulation. No changes in the concentrations of glutamic and aspartic acids were detected in the paraventricular dialysate when sexually potent male rats were exposed to nonreceptive (ovariectomized not oestrogen- and progesterone-primed) female rats or when impotent male rats were used. The injection into the paraventricular nucleus of the excitatory amino acid receptor antagonist dizocilpine (5 micro g), a noncompetitive N-methyl-d-aspartic acid receptor antagonist, reduced noncontact erections and significantly impaired copulatory activity. The alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist 6-cyano-7-nitro-quinoxaline-2,3-dione (5 micro g) was also able to impair copulatory activity, but to a much lower extent than dizocilpine. In contrast, (+/-)-2-amino-4-phosphono-butanoic acid, a metabotropic receptor antagonist (5 micro g), was found to be ineffective. These results confirm the involvement of the paraventricular nucleus in the control of erectile function and copulatory behaviour and show that excitatory amino acid concentration increases in the paraventricular nucleus when penile erection occurs in physiological contexts

    CB1 cannabinoid receptor agonist WIN 55,212-2 decreases intravenous cocaine self-administration in rats

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    The effect of the CB, cannabinoid receptor agonist WIN 55, 212-2 on intravenous cocaine self-administration (IVSA) in rats was evaluated. Male Long Evans rats were implanted with silastic catheters through the external jugular vein. The IVSA was conducted in 3-h daily sessions with a fixed ratio (FR1) schedule: the experimental apparatus had a nose-poking response-like operandum. Intravenous pre-treatment with WIN 55, 212-2 (0.25, 0.5 and 1 mg/kg) to rats self-administering cocaine (0.25 or 0.5 mg/kg/inj) at stable baseline, reduces cocaine intake in a dose-dependent manner. The CB, receptor antagonist SR 141716A (3 mg/kg i.p.) completely reversed the WIN 55, 212-2-induced decrease of cocaine intake. However, pre-treatment of SR 141716A alone (up to dose of 9 mg/kg i.p.) was unable to modify cocaine IVSA. These results indicate that stimulation of CB, cannabinoid receptors activates rewarding mechanisms which produce reinforcing effects additional to those induced by cocaine. (C) 1999 Elsevier Science B.V. All rights reserved

    Extra-cellular dopamine increases in the paraventricular nucleus of male rats during sexual activity

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    Dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations were measured in the dialysate obtained with vertical microdialysis probes implanted into the paraventricular nucleus of the hypothalamus of sexually potent male rats. Animals showed noncontact erections when put in the presence of, and copulated with a receptive (ovarietomized oestrogen and progesterone primed) female rat. Dopamine and DOPAC concentrations in the paraventricular dialysate increased 140% and 19%, respectively, above baseline values during exposure to the receptive female and 280% and 31%, respectively, during copulation. No changes in dopamine and DOPAC concentrations were detected in the paraventricular dialysate when sexually potent male rats were exposed to nonreceptive (ovariectomized not oestrogen plus progesterone primed) female rats. These results confirm the involvement of the paraventricular nucleus in control of erectile function and copulatory behaviour and show for the first time that dopamine neurotransmission is increased in this hypothalamic nucleus when erection occurs in physiological contexts
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