189,639 research outputs found
Genista x rivasgodayana Andrés & Llamas, hybr. nov
No full textA new hybrid between two taxa belonging to two different sections (Erinacoides Spach and Spartioides Spach) of the genus Genista L., G. x rivasgodayana Andrés & Llamas (G. legionensis (Pau) Laínz x G. florida L. subsp. polygaliphylla (Brot.) P.Cout.) is described.Se describe un nuevo híbrido entre dos taxones de secciones distintas (Erinacoi-des Spach y Spartioides Spach) del género Genista L., G. x rivasgodayana Andrés & Llamas (G. legionensis (Pau) Laínz x G. florida L. subsp. polygaliphylla (Brot.) P. Cout.
Llamas in the Rockies
No full textThe use of llamas as pack animals in the United States is increasing in popularity. Llamas cause only light ecological impact, climb and jump well, and are easy to work with.</p
LLAMAS validation data
No full textThis is data collected for real-time validation of EEG-LLAMAS. It consists of recordings conducted with LLAMAS inside the MR scanner, and with brainvision Recorder outside the scanner.Please see the readme for more details.</p
Significance of the Silent Revolution of intensive groundwater use in world water policy
No full textA series of fairly new factors such as virtual water, the rise of desalination technologies and intensive groundwater use currently look as though they will exert a strong influence on future water policy. This chapteris concerned with the latter of the three: the Silent Revolution of intensive groundwater use in arid and semi-arid countries. Over the last half century, millions of farmers have independently drilled their own wells in the pursuit of the socio-economic advantages of groundwater irrigation. This has been due to fairly recent advances in well drilling and pumping, which together with the development of hydrogeology as a solid body of science, have made groundwater more widely available. The intrinsic benefits of groundwater irrigation in relation to traditional surface water systems, such as the ready availability of the resource or the resilience of aquifers against drought, constitute the main reason behind the spectacular groundwater development of many arid and semi-arid countries worldwide. Despite these undeniable benefits, certain problems (mainly related to groundwater quality degradation and water table depletion) have also arisen in some places. While no two cases are the same, a pattern of events can be observed in many of these regions, thus leading to the conceptualisation of this intensive groundwater-based development. Thus, five stages can be distinguished: Hydroschizophrenia, changes in water policy due to the Silent Revolution, Farmer Lobbies, Conservation Lobbies and Social Conflict. In any case, despite the significant role groundwater development is already playing in the eradication of poverty as well as towards fulfilling the United Nation's Millennium Goals, it cannot be seen as a panacea to solve all the world's water problems. These need to be dealt with on a case-by-case basis, in order to achieve an adequate conjunctive management of surface and groundwater resources. Finally, there is a real need to assess and correct the traditional imbalance in favour of conventional surface water systems that exists in most water agencies, and which is the main cause behind important social conflicts.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
128 BOVINE SEMINAL PLASMA INDUCES OVULATION IN LLAMAS
No full text
Ovulation-inducing factor (OIF) is a protein present in the seminal plasma of several species, including llamas, alpacas, pigs, cattle, sheep, horses and rabbits. In an initial study (Ratto et al. 2006 Theriogenology 66, 1102–1106), bovine seminal plasma induced ovulations in 26% (5/19) of llamas compared with 0% (0/19) in the placebo group, but induced proportionately less than in llamas treated with alpaca or llama seminal plasma (100%). It is important to highlight that treatments were based on volume of seminal plasma; the actual dose of OIF was unknown. In a later study (Tanco et al. 2011 Biol. Reprod. doi:10.1095/biolreprod.111.091876), OIF from llama seminal plasma had a dose-dependent effect on ovulation rate, corpus luteum (CL) diameter and progesterone production in llamas. The present study was designed to test the hypothesis that bovine seminal plasma induces ovulation and CL development in llamas comparable with that of llama seminal plasma, based on total dose of OIF. Within species, seminal plasma was pooled from 1 to 4 ejaculates per male (n = 145 bulls, n = 4 llamas). The concentration of OIF in the pooled seminal plasma was measured by radioimmunoassay and the volume of seminal plasma used for treatment was adjusted to reach a total dose of 250 μg of OIF. Mature female llamas were assigned randomly to 4 groups and given a single intramuscular dose of 10 mL of PBS (negative control, n = 5), 50 μg of gonadotropin-releasing hormone (GnRH; positive control, n = 5), 6 mL of llama seminal plasma (n = 6), or 12 mL of bull seminal plasma (n = 6). Ovulation and CL development were monitored by transrectal ultrasonography. The incidence of ovulation was compared among groups by Fisher's exact test. Nonserial data (i.e. follicle size at treatment, maximum CL diameter, day of maximum CL diameter and first day of CL detection) were compared among groups by ANOVA. The diameter of the preovulatory follicle at treatment did not differ among groups (P = 0.10). The incidence of ovulation was 0/5, 4/5, 3/6 and 4/6 in the groups treated with PBS, GnRH, llama seminal plasma and bovine seminal plasma, respectively (P < 0.05). The incidence of ovulation did not differ among llamas treated with GnRH, llama seminal plasma, or bovine seminal plasma. Among the treatments that elicited ovulation, neither the maximum CL diameter nor the day of maximum CL diameter differed (P = 0.30 and P = 0.24, respectively). In addition, no difference was detected in the day of first detection of the CL (P = 0.25). Results document the bioactivity of OIF in the bovine seminal plasma of Bos taurus. These findings further support the notion that OIF is highly conserved among mammals and that seminal plasma exerts its effect in an OIF dose-related manner.
This research was supported by the Natural Sciences and Engineering Research Council of Canada.
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Ovarian estradiol modulates the stimulatory effect of ovulation-inducing factor (OIF) on pituitary LH secretion in llamas
No full textThis study was designed to: 1) characterize the effect of ovulation-inducing factor (OIF) on pituitary LH secretion in ovariectomized (OVX) llamas; and 2) determine the effect of OIF on LH secretion in OVX llamas pretreated with estradiol-17 beta (E-17 beta) or estradiol benzoate (EB). In Experiment 1, intact and OVX llamas (n = 5 or 6 per group) were assigned to a two by two factorial design: 1) Intact llamas treated with 1 mL of phosphate buffered saline (PBS); 2) Intact llamas treated with 1 mg of purified OIF; 3) OVX llamas treated with 1 mL of PBS; or 4) OVX llamas treated with 1 mg of purified OIF. In Experiment 2, intact and OVX llamas (n = 5 or 6 per group) were randomly assigned to the following groups: 1) Intact llamas treated with I mg of purified OIF; 2) OVX llamas treated with 1.0 mL of PBS; 3) OVX llamas treated with 1.0 mg of purified OIF; 4) OVX llamas primed with E-17 beta, followed by 1.0 mg of purified OIF. Experiment 3 was similar as described for Experiment 2, except that priming was done with EB. In Experiment 1, animal category by treatment and animal category by treatment by time interactions tended (P = 0.08) to affect LH concentration. The effect of OIF on LH released was partly restored (P < 0.05), to the values observed for the intact OIF-treated females, when OVX llamas were primed with E-17 beta or BE (Experiments 2 and 3). We concluded that peripheral estradiol concentrations in llamas partially modulates the effect of OIF on pituitary LH secretion; however, other ovarian factor(s) could also participate in this modulatory action. (C) 2012 Elsevier Inc. All rights reserved
Neuroendocrine pathways of nerve growth factor during ovulation in llamas
No full textThe overall objective of this thesis was to investigate the pathways of NGF-induced ovulation in llamas. We hypothesize that NGF influences GnRH secretion directly or indirectly at the median eminence. For this purpose, we used a battery of ultrasonic, histological, endocrine, proteomics, imaging and bioconjugation tools within in vitro and in vivo models to understand the mechanism of action of NGF.
In Chapter 2 we examined the neuroanatomy of the neuroendocrine system of llamas and its relationship to NGF receptors. Using immunohistochemistry, we found that the hypothalamus of llamas contained neuronal groups expressing both NGF receptors (P75 and TrkA) and NGF itself. Although NGF receptors were colocalized in the medial septum and the diagonal band of Broca, both receptors were differentially expressed either in the periventricular area (for TrkA) or, more surprisingly, in circumventricular organs (for P75). Tanycytes in the median eminence had immunoreactivity to P75 and were in close apposition with GnRH and kisspeptin axons.
In Chapter 3 we developed a radioactive NGF (conjugated to 89Zr) for positron emission tomography/computed tomography (PET/CT) imaging to determine the biodistribution and brain uptake of NGF. We validated the bioconjugation, and the stability and bioactivity of the radioactive conjugate using the PC12 cell bioassay. We investigated the biodistribution of radioactive NGF in mice and llamas by gamma counter in the former and PET/CT imaging in the latter species. The majority of NGF radioactivity was present in the kidney (mice and llama) and the liver (llama) 1 hour after administration, whereas the rest of the organs had low radioactivity. In llamas, serial brain scans revealed no substantial uptake in hypothalamic areas of llama, suggesting poor brain penetration of the 89Zr-labelled NGF.
In Chapter 4, we evaluated the role of kisspeptin in inducing LH secretion in llamas. Administration of kisspeptin in llamas induced an increase in LH concentrations and ovulation (5/5), similar to NGF (5/5) but higher than saline administration (0/5). Kisspeptin-induced ovulation in llamas was ablated by pretreatment with a GnRH receptor antagonist, suggesting that kisspeptin is acting at the GnRH neuron level in the hypothalamus of llamas. Kisspeptin neurons were located in the preoptic area and arcuate nucleus, establishing synaptic contacts with GnRH neurons. Interestingly, kisspeptin neurons were devoid of NGF receptors.
In Chapter 5, we tested the hypothesis that noradrenaline mediates the LH surge induced by NGF. Neuroanatomical studies revealed that tyrosine hydroxylase neurons and fibers were present in the hypothalamus establishing appositions with GnRH neurons in llamas. Intravenous administration of alpha-adrenergic receptor antagonist (phenoxybenzamine) failed to prevent or reduce the NGF-induced LH surge, whereas central administration of an alpha-1-adrenergic receptor reduced the magnitude of the LH surge induced by NGF.
In Chapter 6, we evaluated the hypothalamic response to NGF in llamas and the involvement of GnRH neurons and progesterone. Administration of two doses of NGF induced an impaired LH response but not to GnRH administration, suggesting NGF receptor desensitization. No differences were found in FOS expression in GnRH neurons of llamas treated with NGF or saline, and the LH response to NGF in llamas was independent and progesterone concentrations.
In Chapter 7, we evaluated NGF central actions in llamas and the role of kisspeptin receptor in GnRH neurons and TrkA receptor-expressing neurons during the LH surge. Llamas were either treated with saline, high and low doses of NGF intracerebroventricularly or intravenously. Only llamas treated intravenously with NGF displayed an LH surge and ovulation, whereas llamas treated with NGF intracerebroventricularly did not. Infusion of a kisspeptin receptor blocker and a TrkA blocker failed to impair the LH surge induced by NGF.
In Chapter 8, we tested the hypothesis that an LH releasing effect of NGF is present in male camelids. Intravenous administration of NGF induced an immediate elevation of LH concentrations, larger than the response to GnRH. Testosterone concentrations were greater in males that received NGF than males that received saline, suggesting that NGF administration, via LH stimulation, supported blood testosterone concentrations in male south American camelids.
In conclusion, results from the present thesis support the hypothesis that NGF triggers ovulation through a central mechanism of action in llamas. Our results provide evidence that a novel mechanism of action is followed by NGF that may be mediated by noradrenaline, perhaps at the llama median eminence. Additionally, we report that the LH-releasing effect of NGF may be independent of progesterone and kisspeptin and may be operating in male camelids as well
P. Jose Llamas, O. S. A. — Ishaq Israeli : Tratado de los Fiebres. 1945
No full textP. Jose Llamas, O. S. A. — Ishaq Israeli : Tratado de los Fiebres. 1945. In: Revue des études juives, tome 8 (108), janvier-juin 1948. p. 115
Um metaromance histórico: «Jaguar en Llamas», Arturo Arias
No full textResumo: O romance histórico Jaguar en llamas, do escritor guatemalteco Arturo Arias, parodia a história de seu país, subvertendo a história oficial, conforme o procedimento utilizado por outros autores hispano-americanos no final do século XX. Esse romance, no entanto, não se constrói segundo o paradigma convencional, o que o torna um meta romance histórico.Palavras-chave: Literatura guatemalteca; Arturo Arias; Jaguar en Llamas; paródia; romance histórico.Resumen: La novela histórica Jaguar en llamas, del escritor gualtemalteco Arturo Arias, parodia la historia de su país, subvertiendo la historia oficial, de acuerdo con el procedimiento de otros autores hispanoamericanos en el fin del siglo XX, aunque no se construya según el paradigma convencional, lo que hace con que esa novela sea leída y vista como una meta novela histórica.Palabras-clave: Literatura guatemalteca; Arturo Arias; Jaguar en Llamas; parodia; novela histórica.Keywords: Guatemalan literature; Arturo Arias; Jaguar en Llamas; parody; historical novel
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