755 research outputs found
Metamorphism of cordierite gneisses from Eastern Ghat Granulite Terrain, Andhra Pradesh, South India
Cordierite-bearing metapelites of the Eastern Ghat granulite terrain occur in close association of Khondalites, quartzites, calc-silicate rocks and charnockites. Rocks occurring between Bobbili in the north and Guntur in the south of Andhra Pradesh are studied. The association of the mineral and textural relationships suggest the following metamorphic reactions: Garnet + sillimanite + quartz = cordierite, hypersthene + sillimanite + quartz = cordierite, sillimanite + spinel = cordierite + corundum, and biotite + quartz + sillimanite = cordierite + K=feldspar. Generally the minerals are not chemically zoned except garnet-biotite showing zoning when they come in close contact with one another. The potential thermometers are provided by the Fe-Mg distribution of coexisting biotite-garnet and cordierite-garnet. Conflicting interpretation of the P/T dependence of these reactions involving cordierite are due to H2O in the cordierite. The presence of alkali feldspar-quartz assemblage which is common in these gneisses will be constrained from melting only if H2O activity is less than 0.5. The piezometric array inferred is convex towards the temperature array, indicating a rapid and isothermal crustal uplift probably aided by thrust tectonics
States of curiosity modulate hippocampus-dependent learning via the dopaminergic circuit
People find it easier to learn about topics that interest them, but little is known about the mechanisms by which intrinsic motivational states affect learning. We used functional magnetic resonance imaging to investigate how curiosity (intrinsic motivation to learn) influences memory. In both immediate and one-day-delayed memory tests, participants showed improved memory for information that they were curious about and for incidental material learned during states of high curiosity. Functional magnetic resonance imaging results revealed that activity in the midbrain and the nucleus accumbens was enhanced during states of high curiosity. Importantly, individual variability in curiosity-driven memory benefits for incidental material was supported by anticipatory activity in the midbrain and hippocampus and by functional connectivity between these regions. These findings suggest a link between the mechanisms supporting extrinsic reward motivation and intrinsic curiosity and highlight the importance of stimulating curiosity to create more effective learning experiences
Automation of environmental ELISAs
ELISAs for pesticides and herbicides in environmental and
agricultural samples are becoming very important in screening
applications [1-3]. Traditional chromatographic methods are
expensive and results need long turnaround times, making them
incompatible with rapid on-site decision making. ELISA methods
have been shown to meet or exceed the performance of gas
chromatography—they offer rapid low-cost analysis, thereby
increasing the frequency of sampling and enhancing data quality.
Automated ELISA workstations allow the full benefit of these kits
to be realized. Sample preparation, reagent pipetting, incubation,
and photometric evaluation can be performed without user
intervention. Reliability is increased through the elimination of
operator error, better accuracy and precision, and often higher speed.
Much larger batch sizes are possible and these systems can provide
sample tracking with report generation for documentation
requirements. In this paper the manual procedures and ELISA
methods are compared and some critical aspects of automating these
ELISA kits are discussed
Expected reward modulates encoding-related theta activity before an event
Oscillatory brain activity in the theta frequency range (4–8 Hz) before the onset of an event has been shown to affect the likelihood of successfully encoding the event into memory. Recent work has also indicated that frontal theta activity might be modulated by reward, but it is not clear how reward expectancy, anticipatory theta activity, and memory formation might be related. Here, we used scalp electroencephalography (EEG) to assess the relationship between these factors. EEG was recorded from healthy adults while they memorized a series of words. Each word was preceded by a cue that indicated whether a high or low monetary reward would be earned if the word was successfully remembered in a later recognition test. Frontal theta power between the presentation of the reward cue and the onset of a word was predictive of later memory for the word, but only in the high reward condition. No theta differences were observed before word onset following low reward cues. The magnitude of prestimulus encoding-related theta activity in the high reward condition was correlated with the number of high reward words that were later confidently recognized. These findings provide strong evidence for a link between reward expectancy, theta activity, and memory encoding. Theta activity before event onset seems to be especially important for the encoding of motivationally significant stimuli. One possibility is that dopaminergic activity during reward anticipation mediates frontal theta activity related to memory
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Inhibition of apoptotic Bax translocation to the mitochondria is a central function of parkin
Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, affecting 1–3% of the population over 65. Mutations in the ubiquitin E3 ligase parkin are the most common cause of autosomal recessive PD. The parkin protein possesses potent cell-protective properties and has been mechanistically linked to both the regulation of apoptosis and the turnover of damaged mitochondria. Here, we explored these two functions of parkin and the relative scale of these processes in various cell types. While biochemical analyses and subcellular fractionation were sufficient to observe robust parkin-dependent mitophagy in immortalized cells, higher resolution techniques appear to be required for primary culture systems. These approaches, however, did affirm a critical role for parkin in the regulation of apoptosis in primary cultured neurons and all other cells studied. Our prior work demonstrated that parkin-dependent ubiquitination of endogenous Bax inhibits its mitochondrial translocation and can account for the anti-apoptotic effects of parkin. Having found a central role for parkin in the regulation of apoptosis, we further investigated the parkin-Bax interaction. We observed that the BH3 domain of Bax is critical for its recognition by parkin, and identified two lysines that are crucial for parkin-dependent regulation of Bax translocation. Last, a disease-linked mutation in parkin failed to influence Bax translocation to mitochondria after apoptotic stress. Taken together, our data suggest that regulation of apoptosis by the inhibition of Bax translocation is a prevalent physiological function of parkin regardless of the kind of cell stress, preventing overt cell death and supporting cell viability during mitochondrial injury and repair
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CNTRICS Final Task Selection: Long-term Memory
Long-term memory (LTM) is a multifactorial construct, composed of different stages of information processing and different cognitive operations that are mediated by distinct neural systems, some of which may be more responsible for the marked memory problems that limit the daily function of individuals with schizophrenia. From the outset of the CNTRICS initiative, this multidimensionality was appreciated, and an effort was made to identify the specific memory constructs and task paradigms that hold the most promise for immediate translational development. During the second CNTRICS meeting, the LTM group identified item encoding and retrieval and relational encoding and retrieval as key constructs. This article describes the process that the LTM group went through in the third and final CNTRICS meeting to select nominated tasks within the 2 LTM constructs and within a reinforcement learning construct that were judged most promising for immediate development. This discussion is followed by each nominating authors' description of their selected task paradigm, ending with some thoughts about future directions.Psycholog
Opioid substitution treatment with sublingual buprenorphine in Manipur and Nagaland in Northeast India: what has been established needs to be continued and expanded
Manipur and Nagaland in northeast India report an antenatal HIV prevalence of > 1% and the current HIV prevalence among injecting drug users is 24% and 4.5% respectively. Through support from DFID's Challenge Fund, Emmanuel Hospital Association (EHA) established thirteen drop-in-centres across the two states to deliver opioid substitution treatment with sublingual buprenorphine for 1200 injecting drug users. Within a short span of time the treatment has been found to be attractive to the clients and currently 1248 injecting opioid users are receiving opioid substitution treatment. The project is acceptable to the drug users, the families, the communities, religious as well as the militant groups. The treatment centres operate all days of the week, have trained staff members, utilize standardized protocols and ensure a strict supervised delivery system to prevent illicit diversion of buprenorphine. The drug users receiving the substitution treatment are referred to HIV voluntary counselling and testing. As this treatment has the potential to change HIV related risk behaviours, what has been established in the two states needs to be continued and expanded with the support from the Government of India
Performance Analysis of Cooperative Hybrid Cognitive Radio Network with Various Diversity Techniques
The extensive growth in wireless communications leads to spectrum scarcity. Since the spectrum is limited spectrum usage is clogged. The best possible solution is usage of cognitive radio. A cognitive radio network with sender, receiver and intermediate devices as relays is analyzed. The channel is modelled with noise considerations, path loss and variance. The system is defined with one primary sender and one primary receiver, in between them five secondary users and two active users. The signals from all these paths are estimated and analyzed to draw the best signal with good signal to noise ratio (SNR). To improve the channel efficiency and quality, we have considered various diversity techniques for which the fading problem of channel can be eliminated. In view of this, we concentrated on improving the system performance with various diversity techniques and optimum weight adaptation concept
Sourcing complexity factors on contractual relationship: Chinese suppliers’ perspective
To reduce cost and gain competitive advantage, original equipment manufacturers (OEMs) around the world have continued their aggressive sourcing from China. However, sourcing in China has never been a straightforward process and OEMs face both tangible and intangible sourcing complexities with significant negative impact on both expected positive benefits and their contractual relationships with the Chinese suppliers. We developed sourcing complexity model using comprehensive literature review and multiple case studies in various industries to understand the suppliers’ views on sourcing complexity in China. We employed Analytic hierarchy process technique to prioritise identified complexity factors and to derive managerial insights. Our results indicate that tangible complexity factors highly influence the Chinese suppliers’ contractual relationship with OEM’s. Number of suppliers available to OEM’s to procure a component is identified as a primary dominating tangible factor, while differentiation in technical capabilities and operational practices between OEMs and suppliers represents the second biggest issue for Chinese suppliers in establishing contractual relationship with OEM’s
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