1,633 research outputs found

    Effect of van-Hove singularities in single-walled carbon nanotube leads on transport through double quantum dot system

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    The double quantum dot system with single-walled metallic armchair carbon nanotube leads has been studied using Non-equilibrium Green function in the Keldysh formalism. The effect of relative spacing between the energy levels of the dots, interdot tunneling matrix-element, interdot Coulomb interaction and van-Hove singularities in density of states characteristics of quasi-one-dimensional carbon nanotube leads on the conductance of the double quantum dot system has been studied. The conductance and dot occupancies are calculated at finite temperature. It is observed that the density of states of the carbon nanotube leads play a significant role in determining the conductance profile. In particular, whenever the chemical potential of the isolated double quantum dot system is aligned with the position of a van-Hove singularity in the density of states of armchair carbon nanotube leads, the height of the corresponding conductance peak falls considerably. It is further observed that the suppression in the heights of the alternate peaks depends on the relative positions of the energy levels of the dots and their magnitude of separation.Comment: 16 pages and 16 figure

    Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans.

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    BACKGROUND: Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown. RESULTS: We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells. CONCLUSIONS: Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types

    Towards Identifying Performance Anomalies

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    AbstractLarge-scale-software systems (LSSs) are composed of hundreds of subsystems that interact with each other in an unforeseen and complex ways. The operators of these LSSs strictly monitor thousands of metrics (performance counters) to quickly identify performance anomalies before a catastrophe. The existing monitoring tools and methodologies have not kept in pace with the rapid growth and inherit complexity of these LSSs; hence are ineffective in assisting practitioners to effectively pinpoint performance anomalies. We propose a methodology that uses entropy analysis to assist practitioners/operators of LSSs in quickly detecting underlying anomalies in the system. Our performance tests conducted on an open source benchmark system reveal that the proposed methodology is robust in pinpointing anomalies, do not require any domain knowledge to operate, and avoid information overload on practitioners

    Academic Service-Learning In An Accounting Information Systems Capstone Course

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    This paper presents the use of nonprofit organizations in an Accounting Information System (AIS) capstone course to promote Academic Service Learning (ASL).  ASL integrates community service with course requirements, objectives, and outcomes.  Use of a carefully planned field project is an ideal approach to realize these dual objectives of providing meaningful community service with academic learning.  Conclusions drawn from the use of ASL in the capstone course over the last two years are presented

    Team Teaching in Higher Education: Personalities, Leadership Styles, and Preferences

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    Objective: This study aims to find out more about a) certain personality types, leadership styles, and teaching philosophies of those who have participated in team teaching, as well as b) their preferences for team teaching. These preliminary results ought to be helpful to faculty who may be asked to consider team teaching with a colleague(s), and results may help academic administrators assign and match faculty to team teach courses in their program offerings.Background: Given that few faculty have had the opportunity to team teach relative to the numerous courses they offer solo, there is a lack of focus, faculty development opportunities, and research on this subject. This does not, however, diminish the value of this method of delivering courses in higher education. Faculty may explore collaborative teaching in a number of ways, such as inviting a colleague to provide a one-time guest lecture, distributing assignments according to the collaborators' specialized knowledge, or working together on every part of the course.Methods: Using previously developed Myers-Briggs personality type finders and leadership style research tools, the participants' leadership and personality types were identified (Malak et al., 2022). People's experiences with teaching and preferences for leading vs. following were mapped using both qualitative (self-report) and quantitative (survey) approaches.Results: Sixty-three percent of the respondents identified as utilizing either servant leadership or coaching/mentoring. The majority of "E" type personalities like to "Lead," especially in a team-teaching atmosphere, according to this study's findings. The traditional team-teaching method was adopted by 49% of the participants, while 26% used cooperative learning, 11% used integrated learning, 9% used parallel learning, and the remaining 6% used monitoring learning. It is important to highlight that more than 60% of the subjects who had "E" qualities had backgrounds in nursing, public health, health administration, or health care.Conclusions: In summary, the faculty survey data reveal an overall profile of the faculty who have team taught in higher education as an extrovert with a penchant for judging; who prefers to lead rather than follow; uses a coaching/mentoring or servant leadership style; and prefers high level cooperation with a colleague(s) in the full range of teaching/learning activities

    Spectrum of neurological disorders presenting at a neurology clinic in tertiary care hospital in peshawar, pakistan

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    To ascertain the spectrum of different neurological disorders presenting at a tertiary care neurology clinic in Peshawar, Pakistan. Method: A prospective observational study was conducted of all presentations to the neurology clinic in Northwest General Hospital and Research Center, over a period of one year extending from 1st February, 2013 to 31st January, 2014. Study population included 9386 patients from the neurology clinic over the period of one year. The age distribution of all patients was variable; the youngest patient seen was 1 year old while the oldest was 92 years of age. Appropriate history and neurological examination was conducted by consultant neurologist and classified patients into neurological diseases according to the International Classification of Disease (ICD-10) codes for neurology. Statistical analyses were carried out using the software SPSS version 11 and qualitative variables were presented as percentages. Results: A total of 9386 patients were examined and classified into different neurological disorders according to the International Classification of Disease (ICD-10) codes for neurology. Headache was the most common presentation (24%), followed by Cerebrovascular diseases (22%) and Epilepsies (17%). Conclusion: Headache was the most commonclinical presentation for neurology consultation followed by Cerebrovascular accidents (CVA) and epilepsy respectively. Almost all the categories of neurological disorders i.e. Inflammatory, Infective, Neoplastic and Degenerative Diseases were seen in the outpatient neurology clinic

    A rare case of myasthenia gravis with coexisting muscular dystrophy

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    Myasthenia gravis (MG) is an autoimmune disease in which antibodies are directed against postsynaptic membrane of neuromuscular junction, resulting in muscle weakness and fatigability. We report a rare case of an 11 years old boy who was a known case of myasthenia gravis presented with progressive weakness and wasting of facial and limb musculature and was found to have coexisting muscular dystrophy most like facioscapulohumeral muscular dystrophy (FSHD)

    A review on various Smart Grid Technologies used in Power System

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    Electrical infrastructure is expanding day by day due to which smart grid gives better vision for electrical reliability. Various parameters like quality and quantity of power transmitted should be available with the electricity board which can be achieved using smart sensing, metering and communication technologies. If all the above requirements are met in power system then it is called smart grid (SG). SG also helps consumers to manage the load patters and also to manage their expenses. The main component of SG is the communication technology to share data between consumers and grid since grid operators requires real time data to schedule their supply. The Wireless Sensor Network (WSN) uses Aggregation Protocol with Error Detection (APED) to improve the security of data. The SG with SCADA is facilitated by data acquisitions which includes the meter reading, system conditions, etc. that are monitored and transmitted at regular intervals in real time. This paper reviews the modern technologies used in smart grid communication based on IEEE 802.15.4 standard to the SG and how it is modified to ensure effective, efficient and economical and secured communication of the huge real time data from the smart meters
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