The electrophysiological correlates of learning in the developing kitten

The objectives of this experiment were (a) to study the development of classical conditioning in the kitten using light as the conditioned stimulus (CS) , shock as the unconditioned stimulus (US), and leg flexion as the conditioned response; (b) to investigate physiological correlates of learning during the development of classical conditioning such as visual evoked responses (VER), visual following (VF), electrocardiogram (EKG), and galvanic skin response (GSR); and (c) to ascertain the relationship, during development, between physiological and behavioral changes associated with conditioning. Four kittens were exposed to two classical conditioning paradigms. Two Ss received a continuous 10 sec. light paired from the 9th to the 10th sec. with shock, and two received 5 light flashes 2 secs, apart, the last being paired with shock. Four control Ss received the same number of photic stimuli and shocks as their experimental counterparts but on no occasion was light and shock paired. GSR, EKG, VERS and leg-flexion responses were recorded from all 8 animals during a 24 day experimental period. No obvious evidence was found for learning except for suggestive changes in GSR responses. However, it was observed that the development of the short-latency positive and negative N1components of the Ss VERs appeared later than normal or not at all. On the other hand, the long-latency N2 wave demonstrated precociousness showing larger amplitudes and in one of the two paradigms, shorter latencies than normal. The dominant waveform observed throughout the development of the VER in the kittens used in this study was the long-latency negative N2 wave followed by a huge positive after-swing. The typical W-wave usually observed in the adult catTs VER was over-shadowed by the positive-negative complex and in many cases never appeared. A comparison of four VERs obtained from the kitLens in paradigm II (intermittent light) revealed that they were able to give comparable or nearly comparable VERs at 10 days of age to light flashed 2 seconds apart. This suggests that when shocked, the kittens may develop this ability sometime prior to 10 days postnatally. The average latencies of the N2 waves for the kittens used in paradigm I were found to be shorter than that observed in unshocked kittens (Rose, 1971). However, these latencies showed the normal trend of decreasing with age as was observed by Rose

The Effect of Tempo on Prone Hamstring Exercise - An Exploration of Unilateral Bias

Hamstring injuries are common muscle-skeletal injuries with a high recurrence rate. While unmodifiable risk factors (e.g., previous injury) vary, recent evidence has questioned the utility of eccentric exercise in preventing hamstring strains. Furthermore, whether eccentric exercise can transfer to sprinting’s kinetic and kinematic requirements is of question. Therefore, this investigation examines exercise tempo (fast vs. slow eccentric phase), movement strategy (bilateral vs. unilateral), and external load characteristics (coupled vs. independent) bias concentric (CON) and eccentric (ECC) biceps femoris (BF) mean electromyography (mEMG). METHODS: Twenty college-aged students aged 18 – 33 (M = 23.4, SD = 3.12 years) with \u3e3 months of targeted hamstring training \u3e1x per week were recruited and completed two separate lab visits. Lab visits 1 (familiarization) and 2 (experimental protocol) were scheduled for approximately the same time of day, at least 72 hours apart. RESULTS: A main effect of side was detected for BF mEMG during ECC (F (1, 206) = 145.27, p \u3c 0.001) and CON (F (1, 206) = 124.29, p \u3c 0.001). A main effect of tempo was detected for BF (F (1, 206) = 4.144, p = 0.043). The fast tempo (M = 8.20 %MVC, 95% CI: 6.79 to 9.62 %MVC) elicited a higher mEMG when compared to the slow tempo (M = 7.24 %MVC, 95% CI: 5.83 to 8.65 %MVC). Post hoc comparison indicated that the mEMG showed significant differences between tempos (∆M = 0.963 %MVC), p = 0.043. A main effect of side was detected for Gmax ECC (F = (1, 209) 23.28, p \u3c 0.001) and CON (F = (1, 209) 7.85, p = 0.006). CONCLUSION: The prone hamstring exercise resulted in biased recruitment of the contralateral Gmax and BF despite no differences in functional strength ratios (ECC HS [degrees per sec]/ CON Q [degrees per second]). Further investigation is warranted to decipher why this bias exists and whether this phenomenon is a training adaptation or a predictive mechanism for hamstring strain

Geosynchronous Earth Orbit/Low Earth Orbit Space Object Inspection and Debris Disposal: A Preliminary Analysis Using a Carrier Satellite With Deployable Small Satellites

Detailed observations of geosynchronous satellites from earth are very limited. To better inspect these high altitude satellites, the use of small, refuelable satellites is proposed. The small satellites are stationed on a carrier platform in an orbit near the population of geosynchronous satellites. A carrier platform equipped with deployable, refuelable SmallSats is a viable option to inspect geosynchronous satellites. The propellant requirement to transfer to a targeted geosynchronous satellite, perform a proximity inspection mission, and transfer back to the carrier platform in a nearby orbit is determined. Convex optimization and traditional optimization techniques are explored, determining minimum propellant trajectories. Propellant is measured by the total required change in velocity, delta-v. The trajectories were modeled in a relative reference frame using the Clohessy-Wiltshire equations. Mass estimations for the carrier platform and the SmallSat were determined by using the rocket equation. The mass estimates were compared to the mass of a single, non-refuelable satellite performing the same geosynchronous satellite inspection missions. From the minimum delta-v trajectories and the mass analysis, it is determined that using refuelable SmallSats and a carrier platform in a nearby orbit can be more effcient than using a single non-refuelable satellite to perform multiple geosynchronous satellite inspections

A Case of Pituitary Abscess Presenting Without a Source of Infection or Prior Pituitary Pathology

Pituitary abscess is a relatively uncommon cause of pituitary hormone deficiencies and/or a suprasellar mass. Risk factors for pituitary abscess include prior surgery, irradiation and/or pathology of the suprasellar region as well as underlying infections. We present the case of a 22-year-old female presenting with a spontaneous pituitary abscess in the absence of risk factors described previously. Her initial presentation included headache, bitemporal hemianopia, polyuria, polydipsia and amenorrhoea. Magnetic resonance imaging (MRI) of her pituitary showed a suprasellar mass. As the patient did not have any risk factors for pituitary abscess or symptoms of infection, the diagnosis was not suspected preoperatively. She underwent transsphenoidal resection and purulent material was seen intraoperatively. Culture of the surgical specimen showed two species of alpha hemolytic Streptococcus, Staphylococcus capitis and Prevotella melaninogenica. Urine and blood cultures, dental radiographs and transthoracic echocardiogram failed to show any source of infection that could have caused the pituitary abscess. The patient was treated with 6weeks of oral metronidazole and intravenous vancomycin. After 6weeks of transsphenoidal resection and just after completion of antibiotic therapy, her headache and bitemporal hemianopsia resolved. However, nocturia and polydipsia from central diabetes insipidus and amenorrhoea from hypogonadotrophic hypogonadism persisted

Noise Pollution in Teshie-Nungua Schools

Schools located in the Teshie-Nungua area a suburb of Accra, have their background noise levels above 55 dB, the Environmental Protection Agency (EPA) recommended noise level in educational facility. A maximum noise level (Lmax) value of 95.8 dB and a minimum noise level (Lmin) value of 51.6 dB were recorded. In this paper, a Quest Technologies 210 Model sound level meter equipped with a microphone had been used to measure noise levels in schools around the Teshie-Nungua area. It has been shown that about 90 % of the measured schools presented equivalent noise levels (Leq) above 72.5 dB. Pupils were exposed to a high noise pollution level (LNP) value of 95.8 dB and the day and night noise levels (Ldn) in and around the target schools were all above 72 dB. About 98% of schools in the Teshie-Nungua area do not have acoustic materials to minimize noise levels has been established. It was observed that schools in the study area are located in mixed commercial and semi-commercial areas. Nearly 80 % of survey respondents ranked Constant Traffic as number one source of noise. These measured noise levels have the potential to adversely affect the hearing of the pupils in these schools if the required sound proof mechanism is not put in place. Keywords: Equivalent noise level, Noise level, Noise pollution, Teshie-Nungua

A Cloud-Based Architecture for an Affective Recommender System of Learning Resources

Proceedings of: 1st International Workshop on Cloud Education Environments (WCLOUD 2012), Antigua, Guatemala, November 15-16, 2012.One of the most common functionalities in cloudbased learning environments is the recommendation of learning resources. Many approaches have been proposed to deploy recommender systems into an educational environment. Currently, there is an increasing interest in including affective information into the process to generate the recommendations for the learner. In this paper, we propose a cloud-based architecture for a system that recommends learning resources according to the affective state of the learner. Furthermore, we provide the details of an implementation of the architecture along with a discussion on the advantages and disadvantages of the proposal.Work partially funded by the EEE project, “Plan Nacional de I+D+I TIN2011-28308-C03-01”, the “Emadrid: Investigación y desarrollo de tecnologías para el e-learning en la Comunidad de Madrid” project (S2009/TIC-1650), and “Consejo Social - Universidad Carlos III de Madrid”.Publicad

A Widget to Recommend Learning Resources Based on the Learner Affective State

Proceedings of: 3rd International Workshop on Motivational and Affective Aspects in Technology Enhanced Learning (MATEL 2012), Saarbrücken, Germany, 18-19 September , 2012.This paper describes the Learning Resources A ective Recommender, a widget that recommends resources to the learner based on her current a ective state and her learning objectives. The widget is meant to be used in a Personalized Learning Environment in combination with widgets to search for resources. The architecture that supports the widget follows a client-server pattern, with the widget as the client and a recommendation service on the server side. The paper includes the description of both client and server and a discussion about the possibilities of this approach.Work partially funded by the EEE project, "Plan Nacional de I+D+I TIN2011-28308-C03-01", the "eMadrid: Investigación y desarrollo de tecnolog as para el e-learning en la Comunidad de Madrid" project (S2009/TIC-1650), and "Consejo Social - Universidad Carlos III de Madrid".Publicad

Alcohol as a Modifiable Risk Factor for Alzheimer’s Disease—Evidence from Experimental Studies

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by cognitive impairment and memory loss. Epidemiological evidence suggests that heavy alcohol consumption aggravates AD pathology, whereas low alcohol intake may be protective. However, these observations have been inconsistent, and because of methodological discrepancies, the findings remain controversial. Alcohol-feeding studies in AD mice support the notion that high alcohol intake promotes AD, while also hinting that low alcohol doses may be protective against AD. Chronic alcohol feeding to AD mice that delivers alcohol doses sufficient to cause liver injury largely promotes and accelerates AD pathology. The mechanisms by which alcohol can modulate cerebral AD pathology include Toll-like receptors, protein kinase-B (Akt)/mammalian target of rapamycin (mTOR) pathway, cyclic adenosine monophosphate (cAMP) response element-binding protein phosphorylation pathway, glycogen synthase kinase 3-β, cyclin-dependent kinase-5, insulin-like growth factor type-1 receptor, modulation of β-amyloid (Aβ) synthesis and clearance, microglial mediated, and brain endothelial alterations. Besides these brain-centric pathways, alcohol-mediated liver injury may significantly affect brain Aβ levels through alterations in the peripheral-to-central Aβ homeostasis. This article reviews published experimental studies (cell culture and AD rodent models) to summarize the scientific evidence and probable mechanisms (both cerebral and hepatic) by which alcohol promotes or protects against AD progression