936 resultados para egg cortex


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Adjusting behavior following the detection of inappropriate actions allows flexible adaptation to task demands and environmental contingencies during goal-directed behaviors. Post-error behavioral adjustments typically consist in adopting more cautious response mode, which manifests as a slowing down of response speed. Although converging evidence involves the dorsolateral prefrontal cortex (DLPFC) in post-error behavioral adjustment, whether and when the left or right DLPFC is critical for post-error slowing (PES), as well as the underlying brain mechanisms, remain highly debated. To resolve these issues, we used single-pulse transcranial magnetic stimulation in healthy human adults to disrupt the left or right DLPFC selectively at various delays within the 30-180ms interval following false alarms commission, while participants preformed a standard visual Go/NoGo task. PES significantly increased after TMS disruption of the right, but not the left DLPFC at 150ms post-FA response. We discuss these results in terms of an involvement of the right DLPFC in reducing the detrimental effects of error detection on subsequent behavioral performance, as opposed to implementing adaptative error-induced slowing down of response speed.

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We report an experiment where participants observed an attack on their virtual body as experienced in an immersive virtual reality (IVR) system. Participants sat by a table with their right hand resting upon it. In IVR, they saw a virtual table that was registered with the real one, and they had a virtual body that substituted their real body seen from a first person perspective. The virtual right hand was collocated with their real right hand. Event-related brain potentials were recorded in two conditions, one where the participant"s virtual hand was attacked with a knife and a control condition where the knife only struck the virtual table. Significantly greater P450 potentials were obtained in the attack condition confirming our expectations that participants had a strong illusion of the virtual hand being their own, which was also strongly supported by questionnaire responses. Higher levels of subjective virtual hand ownership correlated with larger P450 amplitudes. Mu-rhythm event-related desynchronization in the motor cortex and readiness potential (C3-C4) negativity were clearly observed when the virtual hand was threatened as would be expected, if the real hand was threatened and the participant tried to avoid harm. Our results support the idea that event-related potentials may provide a promising non-subjective measure of virtual embodiment. They also support previous experiments on pain observation and are placed into context of similar experiments and studies of body perception and body ownership within cognitive neuroscience.

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We report an experiment where participants observed an attack on their virtual body as experienced in an immersive virtual reality (IVR) system. Participants sat by a table with their right hand resting upon it. In IVR, they saw a virtual table that was registered with the real one, and they had a virtual body that substituted their real body seen from a first person perspective. The virtual right hand was collocated with their real right hand. Event-related brain potentials were recorded in two conditions, one where the participant"s virtual hand was attacked with a knife and a control condition where the knife only struck the virtual table. Significantly greater P450 potentials were obtained in the attack condition confirming our expectations that participants had a strong illusion of the virtual hand being their own, which was also strongly supported by questionnaire responses. Higher levels of subjective virtual hand ownership correlated with larger P450 amplitudes. Mu-rhythm event-related desynchronization in the motor cortex and readiness potential (C3-C4) negativity were clearly observed when the virtual hand was threatened as would be expected, if the real hand was threatened and the participant tried to avoid harm. Our results support the idea that event-related potentials may provide a promising non-subjective measure of virtual embodiment. They also support previous experiments on pain observation and are placed into context of similar experiments and studies of body perception and body ownership within cognitive neuroscience.

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Total lack of visual experience [dark rearing (DR)] is known to prolong the critical period and delay development of sensory functions in mammalian visual cortex. Recent results show that neurotrophins (NTs) counteract the effects of DR on functional properties of visual cortical cells and exert a strong control on critical period duration. NTs are known to modulate the development and synaptic efficacy of neurotransmitter systems that are affected by DR. However, it is still unknown whether the actions of NTs in dark-reared animals involve interaction with neurotransmitter systems. We have studied the effects of DR on the expression of key molecules in the glutamatergic and GABAergic systems in control and NT-treated animals. We have found that DR reduced the expression of the NMDA receptor 2A subunit and its associated protein PSD-95 (postsynaptic density-95), of GRIP (AMPA glutamate receptor interacting protein), and of the biosynthetic enzyme GAD (glutamic acid decarboxylase). Returning dark-reared animals to light for 2 hr restored normal expression of the above-mentioned proteins almost completely. NT treatment specifically counteracts DR effects; NGF acts primarily on the NMDA system, whereas BDNF acts primarily on the GABAergic system. Finally, the action of NT4 seems to involve both excitatory and inhibitory systems. These data demonstrate that different NTs counteract DR effects by modulating the expression of key molecules of the excitatory and inhibitory neurotransmitter systems

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Henhouse thermal comfort and bird age influence broiler breeder hen productivity; this way, the present research aimed to assess thermal comfort indexes and broiler breeder hen performance during winter in North East semi-arid region from Brazil, using a Cobb Avian 48 broiler strain at the age of 38 and 50 weeks. We measured the following bioclimatic indexes: air temperature and relative humidity, black globe temperature and humidity, CO2 concentration and sound pressure levels at henhouse facility. Data analysis design was complete randomized in a 3 x 3 factorial scheme with three treatments (months) and three replications (week number of collection by month). A number of 25 climatic data were observed. Bioclimatic indexes at the most warm hours throughout the day promoted bird discomfort yet sound pressure and carbon dioxide levels were under the Brazilian standards. Even in thermal comfort zone at some hours, the productivity indexes were in compliance with those recommended by the strain creation guidebook.

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Hen eggs and oats (Avena Sativa) are important materials for the food industry. Today, instead of merely satisfying the feeling of hunger, consumers are asking for healthier, biologically active and environmentally friendly products. The growing awareness of consumers’ increasing demands presents a great challenge to the food industry to develop more sustainable products and utilise modern and effective techniques. The modification of yolk fatty acid composition by means of feed supplements is well understood. Egg yolk phospholipids are polar lipids and are used in several applications including food, cosmetics, pharmaceuticals, and special nutrients. Egg yolk phospholipids are excellent emulsifiers, typically sold as mixtures of phospholipids, triacylglycerols, and cholesterol. However, highly purified and characterised phospholipids are needed in several sophisticated applications. Industrial fractionation of phospholipids is usually based on organic solvents. With these fractionation techniques, some harmful residues of organic solvents may cause problems in further processing. The objective of the present study was to investigate the methods to improve the functional properties of eggs, to develop techniques to isolate the fractions responsible for the specific functional properties of egg yolk lipids, and to apply the developed techniques to plant-based materials, too. Fractionation techniques based on supercritical fluids were utilised for the separation of the lipid fractions of eggs and oats. The chemical and functional characterisation of the fractions were performed, and the produced oat polar lipid fractions were tested as protective barrier in encapsulation processes. Modifying the fatty acid compositions of egg yolks with different types of oil supplements in feed had no affect on their functional or sensory properties. Based on the results of functional and sensory analysis, it is evident that eggs with modified fatty acid compositions are usable in several industrial applications. These applications include liquid egg yolk products used in mayonnaise and salad dressings. Egg yolk powders were utilised in different kinds of fractionation processes. The precipitation method developed in this study resembles the supercritical anti-solvent method, which is typically used in the pharmaceutical industry. With pilot scale supercritical fluid processes, non-polar lipids and polar lipids were successfully separated from commercially produced egg yolk powder and oat flakes. The egg and oat-based polar lipid fractions showed high purities, and the corresponding delipidated fractions produced using supercritical techniques offer interesting starting materials for the further production of bioactive compounds. The oat polar lipid fraction contained especially digalactosyadiacylglycerol, which was shown to have valuable functional properties in the encapsulation of probiotics.

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Kinosternon scorpioides (Linnaeus, 1766), with its common name of jurará, is a quite variable species of turtles, and many different names have been applied to populations throughout its range. Currently, however, four subspecies are considered valid as K. scorpioides arises from southern Panama over most of northern South America and is found in Ecuador, northern Peru, southern Bolivia, northern Argentina, eastern Guyana and Brazil. Thus, an ultrasonographic and radiographic study was performed in order to describe the morphology and development of eggs of 20 female jurará mud turtles K. scorpioides, from September 2005 to August 2006. In the first month, the ovarian cycle was characterized by absence of vitellogenic follicles, atresic follicles or oviduct eggs. From October 2005 to March 2006 on, ultrasonographic scanning allowed to establish the growing vitellogenic follicles. Vitellogenic follicles were observed with spherical to ovoid shapes, with a surrounding echogenic yolk, a nonechogenic albumin layer, and a high echogenic shell. The oviduct eggs were identified by radiography just 180 days after beginning the experiment, when the shell became enough mineralized to impress the radiographic film. This experiment allowed to obtain by means of the 7.5 MHz linear probe images with adequate resolution and penetration for visualization of follicles. Successive ultrasonographic examinations of 20 K. scorpioides females allowed to access initial stages of vitellogenic follicles and oviduct eggs, and radiographic examination revealed to be an easy technique to assess oviduct eggs and to allow evaluation of egg development in jurarás, from 6 months on.

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The aim of this study was to estimate the diagnostic value of renal cortex copper (Cu) concentration in clinical cases of acute copper poisoning (ACP). A total of 97 calves that died due to subcutaneous copper administration were compiled in eleven farms. At least, one necropsy was conducted on each farm and samples for complementary analysis were taken. The degree of autolysis in each necropsy was evaluated. The cases appeared on extensive grazing calf breeding and intensive feedlot farms, in calves of 60 to 200 kg body weight. Mortality varied from 0.86 to 6.96 %, on the farms studied. The first succumbed calf was found on the farms between 6 and 72 hours after the susbcutaneous Cu administration. As discrepancies regarding the reference value arose, the local value (19.9 parts per million) was used, confirming the diagnosis of acute copper poisoning in 93% of the analyzed kidney samples. These results confirm the value of analysis of the cortical kidney Cu concentration for the diagnosis of acute copper poisoning.

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This study aimed to evaluate the variability in the fecal egg count (FEC) and the parasitic burden of naive hair sheep after grazing in nematode infected paddocks. The research was carried out in Tabasco, Mexico, during two periods (August and December). In each period 32 lambs were grazed for one month on African star grass (Cynodon plectostachyus) contaminated with gastrointestinal parasitic nematodes. FEC, packed cell volume (PCV) and body weight (BW) were recorded. Gastrointestinal worms were recovered at necropsy. Data were analyzed with the MIXED procedure of SAS using a model of repeated measurements over time. A higher number of Haemonchus contortus worms was found in December (2814±838) than in August (1166±305). The opposite occurred with Cooperia curticei (2167±393 and 3638±441, respectively). The FEC and correlation coefficient in respect to the worm burden were higher in December (6516 ± 1599, r=0.83, respectively) than in August (4364±771, r=0.44, respectively). A high variability in resistance-susceptibility to gastrointestinal nematodes (GIN) occurred in Katahdin × Pelibuey lambs after grazing.

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A recent (November 2010) outbreak of infectious laryngotracheitis (ILT) in a multi-age laying hen facility in Minas Gerais state, Brazil, is described. Previous ILT outbreak in laying hens was only notified in São Paulo state, Brazil, in 2002. In the outbreak described here, the affected population was approximately eight million hens, with flock sizes ranging from 100,000 to 2,900,000 chickens. The average mortality ranged from 1 to 6%, and morbidity was around 90% (most of the twenty seven farms of the area were positive for ILT virus). Three multi-age laying farms from one company were selected for this report. Clinical signs included prostration, dyspnea, conjunctivitis, occasional swelling of the paranasal sinuses and bloody mucous nasal discharge. Severely affected chickens presented with dyspnea, gasping and became cyanotic before death. At necropsy, these chickens had fibrinous exudate blocking the larynx and the lumen of cranial part of the trachea. In addition, conjunctivitis with intense hyperemia, edema and sinuses with caseous exudate were present. On histopathology, there were marked necrosis and desquamation of respiratory ephitelium and conjunctiva with numerous syncytial cells formation and fibrinous exudate. Moderate to marked non suppurative (especially lymphocytes and plasma cells) infiltration in the lamina propria also was observed. Sixteen out of 20 examined chickens, eosinophilic intranuclear inclusion bodies were observed in the syncytial cells. The DNA extracted from larynx and trachea produced positive PCR results for ILT virus (ILTV) DNA using formalin-fixed, paraffin embedded (FFPE) samples. Amplicons from a small region of ICP4 gene were submitted to sequencing and showed 100% identity with ILTV EU104910.1 (USA strain), 99% with ILTV JN596963.1 (Australian strain) and 91% with ILTV JN580316.1 (Gallid herpesvirus 1 CEO vaccine strain) and JN580315.1 (Gallid herpesvirus 1 TCO vaccine strain).

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The purpose of this study was to investigate the genetic polymorphism of fifteen microsatellites loci in Brazilian (blue-egg Caipira) chickens. Samples were collected from 100 blue eggs of Caipira chickens from rural properties in the city of Dois Lajeados, RS. After DNA extraction, the fragments related to molecular markers LEI0248, LEI0221, LEI0214, LEI0192, LEI0217, LEI0254, LEI0194, LEI0212, MCW0371, ADL0278, LEI0234, MCW0183, MCW0216, MCW0330 and MCW0081 were obtained by polymerase chain reaction (PCR). The statistical analysis were carried out with the softwares ARLEQUIN 3.5 version and CERVUS 3.0.3 version. The allelic and genotypic frequencies, deviations from Hardy-Weinberg equilibrium, estimates of observed (HO) and expected (HE) heterozygosity and polymorphic information content (PIC) were obtained for each marker locus. A total of 186 alleles from 15 loci were obtained, with sizes ranging of 83 to 490 base pairs. The medium number of alleles was 12.4, the HE was 0.76±0.14 and HO was 0.49±0.21 and PIC was 0.706. The first conclusion is that the microsatellites used are polymorphic and can be used to genetic studies in chickens. The second is that the "Caipira" chicken (blue eggs) population investigated has a great genic variability, which makes than an important source of genetic resources for future animal breeding programs.