6,234 research outputs found
Early cellular changes after blockage of chaperone-mediated autophagy
No full textCytosolic proteins can be selectively degraded in lysosomes by chaperone-mediated autophagy (CMA), an autophagic pathway maximally activated under stress. In previous works we have demonstrated the existence of a cross-talk between CMA and macroautophagy, the other stress-related autophagic pathway responsible for the "in bulk" degradation of whole regions of the cytosol and for organelle turnover. We found that chronic blockage of CMA, as the one described in aging cells, results in constitutive activation of macroautophagy, supporting that one pathway may compensate for the other. In this work we have investigated the series of early cellular events that precede the activation of macroautophagy upon CMA blockage and the consequences of this blockage on cellular homeostasis. Shortly after CMA blockage, we have found functional alterations in macroautophagy and the ubiquitin-proteasome system, that are progressively corrected as CMA blockage persists. Basal macroautophagic activity remains initially unaltered, but we observed a delay in its activation in response to serum removal, a well characterized inducer for this pathway. Slower degradation of short-lived proteins, and a transient decrease in some of the proteasome proteolytic activities are also evident in the first stages of CMA blockage. This global alteration of the proteolytic systems supports the coordinated functioning of all of them, and seems responsible for the intracellular accumulation of altered proteins. Based on the time-course of the cellular changes, we propose that a minimal threshold of these toxic products needs to accumulate in order to constitutively activate macroautophagy and thus return cellular homeostasis to normal
Influence of ac ageing on space charge dynamics in LDPE
No full textPolymeric materials have been widely used as insulation in power industry due to their excellent electrical properties. However, these properties deteriorate in time irreversibly when the material is subjected to electric stress. Although space charge is believed to play an important role in ac ageing, exact mechanisms are poorly understood due to very limited experimental data. In the present work efforts have been made to investigate the influence of ac ageing on space charge dynamics in low-density polyethylene (LDPE). LDPE films with 200mm were aged at 50 kV/mm at 50 Hz for various times at ambient temperature. Space charge dynamics in the samples prior to and after ageing were monitored using the pulsed electroacoustic (PEA) technique under dc electric stress. The results indicate that there is a significant amount of homocharge accumulation in the unaged sample due to charge injection. These injected charges are the captured by the deep traps originated from the interface between crystalline and amorphous regions in LDPE. Ageing under ac condition does not necessarily lead to an increase in amount of charge in the bulk but leads to an increase in mobility of charge carriers. Chemical analysis by infrared spectroscope (FTIR) reveals there are chemical changes taken place in the bulk of the material after ac ageing. It is believed that the chemical changes introduce shallow traps which promote the movement of charge carriers in the bulk. Consequently, the injected charges spread across the sample
A power sharing series power BJT array with isolated low voltage control for AC power control applications
No full textA technique for a continuously variable AC resistance using a series BJT array is presented. This array provides high power dissipation capability and uniform voltage and power distribution across the individual transistors. The array, controlled using a set of optoisolators to maintain the electrical isolation between the control circuits and the power stage, could be used as the basis to develop several useful techniques including a solid state AC regulator with comparable performance to the commonly used ferro-resonant systems; a linear AC electronic load suitable for testing UPS and other power conditioners; and, in other AC power control applications such as switching capacitors in AC resonant circuits
Winston Massey, Cheerleader 1
No full textWinston Massey was a student at Jacksonville State College (now Jacksonville State University in the mid 1960s. He was a 1964-1965 Cheerleader. Here he stands mid cheer outside on campus.https://digitalcommons.jsu.edu/lib-ac-histimg/16129/thumbnail.jp
Winston Massey, Cheerleader 2
No full textWinston Massey was a student at Jacksonville State College (now Jacksonville State University in the mid 1960s. He was a 1964-1965 Cheerleader. Shown he is in air mid cheer.https://digitalcommons.jsu.edu/lib-ac-histimg/16130/thumbnail.jp
Female Students Surround Winston Massey Lying on Floor
No full textA group of female students prop a leg on male student Winston Massey lying in the floor at Jacksonville State College. Identified female students are Sue McDonald, Winston Massey, and Kaye Chisenhall.https://digitalcommons.jsu.edu/lib-ac-histimg/31199/thumbnail.jp
Management of threats and errors in normal operations of assistant controllers : a thesis presented in partial fulfilment of the requirements for the degree of Master in Aviation at Massey University
No full text"To err is indeed human, so to err is normal" Human errors are usually pronounced in accident or incident reports. Seldom does one pay enough attention to these errors during daily normal operations as these either go unnoticed or unreported for whatsoever the reasons may be. Therefore, the causes of these errors and also the system threats prevalent in the daily operations may not be fully contained. On the other hand, problematic situations that are successfully tackled by human skills are quite often treated as less important than they really are. The job of an assistant controller (AC) is one of the important domains in air traffic management (ATM). The AC work together with air traffic controllers as team members and they do have direct and indirect contributions to the safe, orderly and efficient flow of air traffic. In this study, the threats, errors and potential undesired states occurring with AC during normal operations will be recorded by a methodology, which is new to Hong Kong Air Traffic Control (ATC). This methodology, called Normal Operations Safety Observation (NOSO), is built on the Threat and Error Management (TEM) framework. The results will generate a broad outline on what sorts of threats, errors and undesired states an AC can be facing during normal operations. The relative frequencies of occurrence of these conditions will be presented separately in tables and figures. The AC's potential vulnerabilities and capabilities to cope with these threats, errors and undesired states will be discussed together with a suggested ranking. It is envisaged that an analysis of the data collected will aid the development and evaluation of safety defence measures in ATM and further support the applicability of this data collection methodology in other ATM operations and subsequent researches. KEYWORDS:- Normal Operations Safety Observation, Threat and Error Management, Safety Management, Air Traffic Control
Winston Massey, 1965-1966 Cheerleader 2
No full textWinston Massey was a student at Jacksonville State College (now Jacksonville State University). In 1965-1966 he was a cheerleader. Shown outside in uniform he poses on campus in the grass.https://digitalcommons.jsu.edu/lib-ac-histimg/26647/thumbnail.jp
Winston Massey, 1965-1966 Cheerleader 1
No full textWinston Massey was a student at Jacksonville State College (now Jacksonville State University). In 1965-1966 he was a cheerleader. Shown outside in uniform he poses on campus in the grass.https://digitalcommons.jsu.edu/lib-ac-histimg/26646/thumbnail.jp
Ecology of pastoral communities in a heterogeneous environment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Pastoral Science at Massey University, Palmerston North, New Zealand
No full textA group of studies was conducted to examine environmental variables and pasture components and their relationships in heterogeneous hill country pasture. Four studies were conducted in relation to the hill country grassland ecosystem of New Zealand. 1. The effects of long-term fertiliser-stocking rate and hill country slope category (LS Low slope, 0-12° MS Medium slope, 13-25° HS High slope, ?25°) on soil physical and fertility attributes and pasture production were examined. Field treatments, high fertility-high stocking rate (HH) and low fertility-low stocking rate (LN), have been applied to paddocks since 1975. Soil samples were taken from the slope categories of the two field treatments (microsites) and physical and fertility features were analysed. Dry matter production through the year was also measured from these units. The soil attributes that explained the largest percentage of the differences between microsites were water holding capacity (WHC), water conductivity (Kunsat), slope, soil compressibility (SC), bulk density (BD), Olsen-P, soil total nitrogen (Total-N) and soil rebound after compression (SR). Slope led to greater differences between soil features of microsites than fertiliser and stocking rate history. Dry matter production increased with increasing Total-N, Olsen-P, WHC and SC, and decreasing slope, Kunsat, BD and SR. 2. The presence of plant functional groups, species segregation and their relationship with soil features were analysed. The relationship between field condition and plant functional group was also examined. The evaluation was conducted in the same sites as the first study. The pasture botanical composition for each microsite was measured through the year and plant functional groups determined. The relationship between the presence of plant species and the soil attributes WHC, Kunsat, slope, SC, BD, Olsen-P, Total-N and SR (from the first study) and plant functional groups were studied, as well as the field condition-plant functional groups relationship. Seven functional groups were determined. High fertility grasses and Lolium perenne (Lp) were associated with LS and high availability of resources, while low fertility species were segregated to HS. Groups of species such as Agrostis capillaris (Ac) were indifferent to environmental changes. Functional groups proved to be good indicators of soil development. Field condition and plant functional groups were complementary concepts in grassland dynamic analyses. 3. Sheep grazing behaviour was examined in relation to slope category and plant species selection. The study was conducted in the same microsites as studies 1 and 2. Transects with marked tillers of Anthoxanthum odoratum (Ao), Ac and Lp were placed in the slope categories as follows: Ac and Lp in LS; Ac, Ao and Lp in MS; and Ac and Ao in HS. The evaluation was carried out during 4 weeks in each of Summer, Autumn, Winter and Spring, and records of grazed and ungrazed tillers were analysed. Pasture growth rates were calculated through the year. During Spring sheep grazed mainly the LS. With decreasing availability of pasture, sheep enlarged their grazing areas towards the HS. Species selection was only present during Winter when pasture availability was low. In Winter sheep also grazed in all slope categories and selected Lp over of Ac but showed no selection for Ao. 4. Ecotype segregation and plant phenotypic plasticity were examined. Plant material was collected from the extremes of the environmental gradient analysed in studies 1, 2 and 3 and grown in glasshouse conditions under five levels of phosphorus and three of nitrogen in the soil. The plants in each pot were cut on three occasions and total dry matter was calculated. Height, plant architecture, plant horizontal expansion and leaf growth were analysed for Cynosorus cristatus (Cc), Holcus lanatus (HI), Ac, Ao and Lp. Morphological and physiological differences were present between genotypes of Lp whereas only physiological genotypic differences existed in Ao and Cc. Consistent differences were not found between HI genotypes. Thus, Ao, Cc and Lp showed ecotype differentiation. Ac genotypes showed high plasticity with no ecotype differentiation
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