898 resultados para prey capture
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Biogeography is the science that studies the geographical distribution and the migration of species in an ecosystem. Biogeography-based optimization (BBO) is a recently developed global optimization algorithm as a generalization of biogeography to evolutionary algorithm and has shown its ability to solve complex optimization problems. BBO employs a migration operator to share information between the problem solutions. The problem solutions are identified as habitat, and the sharing of features is called migration. In this paper, a multiobjective BBO, combined with a predator-prey (PPBBO) approach, is proposed and validated in the constrained design of a brushless dc wheel motor. The results demonstrated that the proposed PPBBO approach converged to promising solutions in terms of quality and dominance when compared with the classical BBO in a multiobjective version.
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Advances in the understanding of ecological factors determining predatorprey interactions have provided a strong theoretical background on diet preferences of predators. We examined patterns of jaguar predation on caiman in southern Pantanal, Brazil. We investigated factors affecting predation rates and vulnerability of caiman to predation by jaguars. We recorded 114 caiman mortality incidents. Predation accounted for 62.3% (n = 71) of all caiman found dead, while other causes of mortality (nonpredation) accounted for 37.7% (n = 43). We found that jaguars prey on a broad size range of caiman body and caiman predation was influenced by distance to forests. During dry seasons, 70% (n = 49) of deaths were due to predation, while 30% (n = 21) were due to nonpredation causes. However, we found no significant relationship between annual and monthly killings of caiman and rainfall totals by year and month (r = 0.130, r = -0.316). The annual flooding regime may be a more important factor influencing prey selection by jaguars. Although neotropical crocodilians are relatively well studied, their interactions with jaguars have been mostly ignored and should be prioritized in future studies.
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[EN] The information provided by the International Commission for the Conservation of Atlantic Tunas (ICCAT) on captures of skipjack tuna (Katsuwonus pelamis) in the central-east Atlantic has a number of limitations, such as gaps in the statistics for certain fleets and the level of spatiotemporal detail at which catches are reported. As a result, the quality of these data and their effectiveness for providing management advice is limited. In order to reconstruct missing spatiotemporal data of catches, the present study uses Data INterpolating Empirical Orthogonal Functions (DINEOF), a technique for missing data reconstruction, applied here for the first time to fisheries data. DINEOF is based on an Empirical Orthogonal Functions decomposition performed with a Lanczos method. DINEOF was tested with different amounts of missing data, intentionally removing values from 3.4% to 95.2% of data loss, and then compared with the same data set with no missing data. These validation analyses show that DINEOF is a reliable methodological approach of data reconstruction for the purposes of fishery management advice, even when the amount of missing data is very high.
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[EN] Since paralarval rearing is still the main bottleneck for the development of octopus culture, the aim of the present study was to obtain some information on the feeding strategy and nutritional requirements during paralarval stage. For that purpose just hatched out octopus paralarvae were fed with live preys in three different combinations, trying to match their natural food: Enriched Artemia metanauplii, Grapsus grapsus zoeas supplemented with enriched Artemia, and Plagusia depressa zoeas supplemented with enriched Artemia. Paralarval treatments were carried out during 28 days in triplicates; fibre glass 120 l tanks in flow through system were used. Growth, in terms of dry body weight, mantle length and width, was determined each seven days. A histological study of the paralarval development was carried out. Biochemical composition of preys and paralarvae were determined. Growth was significantly better in paralarvae fed with zoeas and Artemia than in those fed only with Artemia, from day 8 after hatching. Besides a clear effect on the digestive gland histology morphology was observed.
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This study aimed to investigate which genes Cnidaria use for photoreception and test whether Gi alpha subunit protein is involved in the phototransduction cascade, giving additional tools to investigate light-mediated behaviors, as nematocyte firing. Here, I engineered an opsin gene promoter construct useful to test whether nematocyte sensory cells express opsin gene. By determining the expression of one of the unique EST opsin genes of the eyeless hydrozoan Hydra magnipapillata genome in nematocyte sensory cells, we will be able to investigate whether light modulation is an ancestral feature in Cnidaria, and whether regulation of nematocyte discharge by opsin-mediated phototransduction predated this pathway’s function in cnidarian eyes. Nematocytes, the cnidarians stinging cells, discharge nematocysts to capture prey. As nematocysts are energetically expensive, the discharge is tightly regulated and occurs after proper chemical and mechanical stimulation. Cnidarians are also known to display a rich corpus of photobehaviors, which are often associated with activities that involve nematocytes. Previous experiments on nematocyst firing modulation show that light decreases nematocyte firing. This study contributed to confirm that bright light decreases the tendency for nematocytes to discharge in Haliplanella luciae. Similar findings in cubozoan and hydrozoan lead us to believe that light modulation of cnidocytes may be an ancestral feature of Cnidaria. Experimentally, I found no evidence that pertussis toxin, a Gi alpha subunit protein inhibitor, ablates Hydra magnipapillata photobehaviour, preliminary suggesting that Gi alpha subunit protein is not involved in photoresponse. I found no significant association between pertussis toxin and nematocyte firing in Haliplanella luciae both in conditions of dim and bright light, suggesting that Gi alpha subunit protein is not involved in photoresponse. We have preliminary evidence for a prevalence of photoreception over chemoreception, tending toward conditions of bright light. This finding may suggest the involvement of a Gs alpha subunit protein in Haliplanella luciae phototransduction pathway. While nematocyte chemo- and mechano-sensitivity have been extensively studied, further research is necessary to better understand what an ancestral phototransduction cascade looked like, and how opsin-based phototransduction acts to regulate nematocyte discharge.
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Die Bor-Neuroneneinfang-Therapie (engl.: Boron Neutron Capture Therapy, BNCT) ist eine indirekte Strahlentherapie, welche durch die gezielte Freisetzung von dicht ionisierender Strahlung Tumorzellen zerstört. Die freigesetzten Ionen sind Spaltfragmente einer Kernreaktion, bei welcher das Isotop 10B ein niederenergetisches (thermisches) Neutron einfängt. Das 10B wird durch ein spezielles Borpräparat in den Tumorzellen angereichert, welches selbst nicht radioaktiv ist. rnAn der Johannes Gutenberg-Universität Mainz wurde die Forschung für die Anwendung eines klinischen Behandlungsprotokolls durch zwei Heilversuche bei Patienten mit kolorektalen Lebermetastasen an der Universität Pavia, Italien, angeregt, bei denen die Leber außerhalb des Körpers in einem Forschungsreaktor bestrahlt wurde. Als erster Schritt wurde in Kooperation verschiedener universitärer Institute eine klinische Studie zur Bestimmung klinisch relevanter Parameter wie der Borverteilung in verschiedenen Geweben und dem pharmakokinetischen Aufnahmeverhalten des Borpräparates initiiert.rnDie Borkonzentration in den Gewebeproben wurde hinsichtlich ihrer räumlichen Verteilung in verschiedenen Zellarealen bestimmt, um mehr über das Aufnahmeverhalten der Zellen für das BPA im Hinblick auf ihre biologischen Charakteristika zu erfahren. Die Borbestimung wurde per Quantitative Neutron Capture Radiography, Prompt Gamma Activation Analysis und Inductively Coupled Plasma Mass Spectroscopy parallel zur histologischen Analyse des Gewebes durchgeführt. Es war möglich zu zeigen, dass in Proben aus Tumorgewebe und aus tumorfreiem Gewebe mit unterschiedlichen morphologischen Eigenschaften eine sehr heterogene Borverteilung vorliegt. Die Ergebnisse der Blutproben werden für die Erstellung eines pharmakokinetischen Modells verwendet und sind in Übereinstimmung mit existierenden pharmakokinetische Modellen. Zusätzlich wurden die Methoden zur Borbestimmung über speziell hergestellte Referenzstandards untereinander verglichen. Dabei wurde eine gute Übereinstimmung der Ergebnisse festgestellt, ferner wurde für alle biologischen Proben Standardanalyseprotokolle erstellt.rnDie bisher erhaltenen Ergebnisse der klinischen Studie sind vielversprechend, lassen aber noch keine endgültigen Schlussfolgerungen hinsichtlich der Wirksamkeit von BNCT für maligne Lebererkrankungen zu. rn
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The aim of this work is to provide a precise and accurate measurement of the 238U(n,gamma) reaction cross-section. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. In particular, fast neutron reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region inconsistencies between the existing measurements are present up to 15%, and the most recent evaluations disagree each other. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross-section of 238U should be further reduced to 1-3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were scheduled within the ANDES project within the 7th Framework Project of the European Commission. The results of one of the 238U(n,gamma) measurement performed at the n_TOF CERN facility are presented in this work, carried out with a detection system constituted of two liquid scintillators. The very accurate cross section from this work is compared with the results obtained from the other measurement performed at the n_TOF facility, which exploit a different and complementary detection technique. The excellent agreement between the two data-sets points out that they can contribute to the reduction of the cross section uncertainty down to the required 1-3%.
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For the improvement of current neutron capture therapy, several liposomal formulations of neutron capture agent gadolinium were developed and tested in a glioma cell model. Formulations were analyzed regarding physicochemical and biological parameters, such as size, zeta potential, uptake into cancer cells and performance under neutron irradiation. The neutron and photon dose derived from intracellular as well as extracellular Gd was calculated via Monte Carlo simulations and set in correlation with the reduction of cell survival after irradiation. To investigate the suitability of Gd as a radiosensitizer for photon radiation, cells were also irradiated with synchrotron radiation in addition to clinically used photons generated by linear accelerator.rnIrradiation with neutrons led to significantly lower survival for Gd-liposome-treated F98 and LN229 cells, compared to irradiated control cells and cells treated with non-liposomal Gd-DTPA. Correlation between Gd-content and -dose and respective cell survival displayed proportional relationship for most of the applied formulations. Photon irradiation experiments showed the proof-of-principle for the radiosensitizer approach, although the photon spectra currently used have to be optimized for higher efficiency of the radiosensitizer. In conclusion, the newly developed Gd-liposomes show great potential for the improvement of radiation treatment options for highly malignant glioblastoma.rn
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L'elaborato descrive il lavoro svolto in cinque mesi presso il Centro Protesi INAIL di Budrio (BO), che ha portato allo sviluppo di un banco prova per testare articolazioni elettromeccaniche. I dispositivi target, in particolare, sono stati due gomiti mioelettrici: il primo di produzione interna INAIL e il secondo prodotto da Selex ES in collaborazione con il Centro Protesi stesso. Per il controllo del movimento e l'acquisizione dei segnali elettrici si è scelto il PAC CompactRIO (National Instruments), mentre per le acquisizioni cinematiche di angolo e velocità angolare si è sfruttata la stereofotogrammetria.
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Con il passare degli anni le tecnologie nel campo delle protesi mioelettriche di arto superiore stanno compiendo sempre più passi in avanti. In questo elaborato di tesi si darà un iniziale introduzione sulla protesica di arto superiore cercando di coprire tutte le possibili tipologie di protesi, prestando particolare attenzione agli arti artificiali mioelettrici. Gli scopi di questo studio sono in prima analisi una miglioria dell'unità di controllo di una protesi comandata da segnali elettromiografici di superficie, tramite l'utilizzo del nuovo IDE della Microchip (MPLAB X). In seconda analisi, invece, si attuerà un confronto prestazionale a livello di consumo in corrente di un prototipo di protesi mioelettrica nata dalla sinergia tra l'azienda "Selex ES" e il "Centro Protesi INAIL di Vigorso di Budrio". Per questo studio ci si è serviti di stereofotogrammetrica per la determinazione delle grandezze meccaniche, mentre tramite un sistema PAC si è riusciti ad ottenere specifiche grandezze elettriche. Lo studio ha portato, a livello di Firmware, l'inserimento del giusto comando di attuazione di un servofreno comandato in corrente e l'introduzione di una particolare modalità a basso consumo che consente un risparmio energetico di circa il 60% rispetto alla vecchia modalità. Discorso diverso per i risultati del confronto prestazionale che non ha portato ai risultati sperati in fase di progetto.
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Catheter ablation procedures for atrial fibrillation (AF) often involve circumferential antral isolation of pulmonary veins (PV). Inability to reliably identify conduction gaps on the ablation line necessitates placing additional lesions within the intended lesion set.
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Molecular genetic testing is commonly used to confirm clinical diagnoses of inherited urea cycle disorders (UCDs); however, conventional mutation screenings encompassing only the coding regions of genes may not detect disease-causing mutations occurring in regulatory elements and introns. Microarray-based target enrichment and next-generation sequencing now allow more-comprehensive genetic screening. We applied this approach to UCDs and combined it with the use of DNA bar codes for more cost-effective, parallel analyses of multiple samples.