230 research outputs found
Roughening of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>k</mml:mi></mml:math> -mer–growing interfaces in stationary regimes
No full textWe discuss the steady-state dynamics of interfaces with periodic boundary conditions arising from body-centered solid-on-solid growth models in 1+1 dimensions involving random aggregation of extended particles (dimers, trimers,⋯,k-mers). Roughening exponents as well as width and maximal height distributions can be evaluated directly in stationary regimes by mapping the dynamics onto an asymmetric simple exclusion process with k-type of vacancies. Although for k≥2 the dynamics is partitioned into an exponentially large number of sectors of motion, the results obtained in some generic cases strongly suggest a universal scaling behavior closely following that of monomer interfaces.Fil: Grynberg, Marcelo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Schaposnik Massolo, Fidel Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Institute for Basic Science; Corea del Su
Agonistic behaviour of Scarites buparius (Forster, 1771) (Coleoptera : Carabidae) in relation to body size
No full textIntra-male aggressive behaviour of Scarites buparius was analysed; agonistic interaction between males consisted of a repeated series of fighting events. We defined this behaviour as "agonistic" because a dominance/submission status was established. We measured the males and found that the attack behaviour persistence is correlated with the body length. RI Massolo, Alessandro/I-3437-201
Social hackers: Integration in the host chemical recognition system by a paper wasp social parasite
No full textObligate social parasites in the social insects have lost the worker caste and the ability to establish nest. As a result, parasites must usurp a host nest, overcome the host recognition system, and depend on the host workers to rear their offspring. We analysed cuticular hydrocarbon profiles of live parasite females of the paper wasp social parasite Polistes sulcifer before and after usurpation of host nests, using the non-destructive technique of solid-phase micro-extraction. Our results reveal that hydrocarbon profiles of parasites change after usurpation of host nests to match the cuticular profile of the host species. Chemical evidence further shows that the parasite queen changes the odour of the nest by the addition of a parasite-specific hydrocarbon. We discuss the possible role of this in the recognition and acceptance of the parasite and its offspring in the host colony. RI Massolo, Alessandro/I-3437-201
A difficult choice for tiny pests:host-seeking behaviour in Xenos vesparum triungulins
No full textThe first-instar larvae of strepsipteran parasites, commonly referred to as otriungulinso, are the host-seeking stage: they must locate, invade and successfully develop in the new host, in order to start their parasitic cycle. Little information is available about the behaviour of Xenos vesparum triungulins. They emerge in batches from the endoparasitic female infecting Polistes dominulus, the primary host, and reach the nest through a vector (a foraging wasp or the parasitised wasp itself). Once there, they have the possibility to penetrate into wasp immatures at different developmental stages. In this study, we performed preliminary analyses aimed to investigate which cues are important to direct triungulin movements during their brief stay in wasp nests. In laboratory conditions we selectively presented different stimuli to Xenos larvae: apparently, the host larva itself is attractive in an open arena, but not inside a confined space, nor are epicuticular compounds of wasp larvae able to control triungulin movements. These are more likely oriented by their gregarious behaviour, whereas light (positive phototaxy) may at a previous stage enhance their emergence via the brood canal opening in the female cephalothorax
Notes on the status and conservation of the reem gazelle Gazella subgutturosa marica in the Sultanate of Oman
No full textThe status of the reem gazelle in Oman is uncertain. We collected all recent data available, and carried out surveys to assess
the feasibility of a conservation project in Oman. Despite a previous survey in 1986, data regarding the population density
and the group size were not available. In 2000 we carried out a 2-day survey (line transect by car) in the central sand desert
of Oman, covering 128km for a total sampled area of 62km2. Three herds and one lone individual were sighted and
approached by car, whilst the tracks of four others were found. In total we recorded 78 gazelles (estimated density 1.26 ind/
km2); 44 were sighted and 34 were tracked. Group size ranged from 4 to 20 ind/herd, with a mean of 14 ind/herd¡2 SD.
Evidence of gazelle poaching was detected twice during this survey and more evidence was collected in 2005, suggesting that
illegal killing and live capture is a common problem. A conservation strategy was suggested with increasing severity of
management options
Long-term GnRH-agonist administration revealed a GnRH-independent mechanism stimulating FSH discharge in humans
No full textThe present study evaluated the FSH and LH episodic discharge in different physiopathological conditions undergoing chronic GnRH-agonist administration. Four girls with true precocious puberty and five postmenopausal women were administered GnRH-agonist (3.73 leuprolide acetate every 4 weeks; Takeda Italia, Rome, Italy) for at least 4 months. Plasma LH and FSH secretory profiles were assessed before and under GnRH-agonist administration (after 21 and 120 days). Pulsatility studies were conducted for 4 h in the girls and for 6 h in postmenopausal women, with blood sampling intervals of 10 min. Pubertal and postmenopausal patients showed the distinct episodic co-secretion of LH and FSH before GnRH-agonist administration; this co-secretion disappeared in both groups after 21 and 120 days of treatment. Moreover, while LH concentrations decreased to almost undetectable levels and LH episodic release disappeared, FSH plasma levels were only partially reduced and FSH episodic secretion was detectable in both groups. In conclusion, this study demonstrated that long-term GnRH-agonist administration blocked LH but not FSH episodic release. These data enforce the hypothesis that FSH episodic discharge might be dependent not only on hypothalamic GnRH, but also on a GnRH-independent stimulatory pathwa
Morphometry and eye morphology in three species of Carabus (Coleoptera: Carabidae) in relation to habitat demands
No full textMorphological features of three common European olfactory hunting carabid beetles, Carabus coriaceus mediterraneus Born, 1906, Carabus lefebvrei Dejean, 1826 and Carabus preslii neumeyeri Schaum, 1856, were compared. According to eye measurements, the three species are nocturnal and/or twilight hunters. They differ, however, in relative length of the antennae, relative surface area of the compound eyes, density of ommatidia and relative head width. These differences can be correlated with the species-specific habitat demands (light intensity, open land or shaded places). In particular, the greater lateral eye protrusion in C. lefebvrei corresponds to its tree-climbing habits, while the larger relative eye surface area and ommatidia density in C. coriaceus correspond to its choice of open habitats. © 2007 The Authors Journal compilation 2007 Blackwell Verlag
Evidence suggesting an additional control mechanism regulating episodic secretion of luteinizing hormone and follicle stimulating hormone in pre-pubertal children and post-menopausal women
No full textThe possible differential regulation of pulsatile follicle stimulating hormone (FSH) and luteinizing hormone (LH) secretion in pre-pubertal children and in post-menopausal women was investigated. Children were studied for 4 h and post-menopausal women for 6 h; blood samples were taken every 10 min. Post-menopausal women were studied before and 21 days after administration of a single i.m. dose of gonadotrophin-releasing hormone (GnRH) analogue. Eight post-menopausal women and 18 children (nine boys and nine girls) were enrolled. The children were divided into two groups: A, at Tanner stages 0-1 (four boys and three girls); B, at Tanner stage 2-3 (five boys and six girls). Plasma LH and FSH concentrations were determined using an immunofluorimetric assay. Time series were analysed and the specific concordance (SC) index was computed to determine the degree of concordance between episodes of LH and FSH secretion. While children of group A had LH concentrations below the minimal detectable dose of 0.1 IU/l, group B showed measurable LH plasma concentrations (1.4 +/- 0.3 IU/l, mean +/- SEM). Plasma FSH concentrations were detectable in both groups. Group A showed FSH plasma concentrations significantly lower than those of group B (0.75 +/- 0.2 and 1.95 +/- 0.4 IU/l respectively; P < 0.05), but FSH pulse frequency was higher in group A (P < 0.05). Children of group B showed significant concomitance of LH and FSH secretory events at time 0 (P < 0.05)
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