371 research outputs found
Using energy network science (ENS) to connect resilience with the larger story of systemic health and development
An electricity generation planning framework incorporating adaptation to hydroclimatic change is presented. The planning framework internalizes risks and opportunities associated with alternative hydro-climate scenarios to identify a long-term systems configuration robust to uncertainty. The implications of a robust response to hydro-climatic change are demonstrated for the electricity system in British Columbia (BC), Canada. Adaptation strategy is crucial in this region, mainly due to the large contribution of hydropower resources to regional electricity supply. Analysis of results from basin-scale hydrologic models driven with downscaled global climate data suggest that shifts in regional streamflow characteristics by the year 2050 are likely to increase BC's annual hydropower potential by more than 10 %. These effects combined with an estimated decrease in electricity demand by 2 % due to warmer temperatures, could provide an additional 11 TWh of annual energy. Uncertainties in these projected climate impacts indicate technology configurations offering significant long-term operational flexibility will be needed to ensure system reliability. Results from the regional long-term electricity generation model incorporating adaptive capacity show the significant shifts required in the non-hydro capacity mix to ensure system robustness cause an increase in cumulative operating costs of between 1 and 7 %. Analysis of technology configurations involving high-penetrations of wind generation highlights interactions between flexibility requirements occurring over multiple temporal scales
PDC IC WELD FAILURE EVALUATION AND RESOLUTION
During final preparations for start of the PDCF Inner Can (IC) qualification effort, welding was performed on an automated weld system known as the PICN. During the initial weld, using a pedigree canister and plug, a weld defect was observed. The defect resulted in a hole in the sidewall of the canister, and it was observed that the plug sidewall had not been consumed. This was a new type of failure not seen during development and production of legacy Bagless Transfer Cans (FB-Line/Hanford). Therefore, a team was assembled to determine the root cause and to determine if the process could be improved. After several brain storming sessions (MS and T, R and D Engineering, PDC Project), an evaluation matrix was established to direct this effort. The matrix identified numerous activities that could be taken and then prioritized those activities. This effort was limited by both time and resources (the number of canisters and plugs available for testing was limited). A discovery process was initiated to evaluate the Vendor's IC fabrication process relative to legacy processes. There were no significant findings, however, some information regarding forging/anneal processes could not be obtained. Evaluations were conducted to compare mechanical properties of the PDC canisters relative to the legacy canisters. Some differences were identified, but mechanical properties were determined to be consistent with legacy materials. A number of process changes were also evaluated. A heat treatment procedure was established that could reduce the magnetic characteristics to levels similar to the legacy materials. An in-situ arc annealing process was developed that resulted in improved weld characteristics for test articles. Also several tack welds configurations were addressed, it was found that increasing the number of tack welds (and changing the sequence) resulted in decreased can to plug gaps and a more stable weld for test articles. Incorporating all of the process improvements for the actual can welding process, however, did not result in an improved weld geometry. Several possibilities for the lack of positive response exist, some of which are that (1) an insufficient number of test articles were welded under prototypic conditions, (2) the process was not optimized so that significant improvements were observable over the 'noise', and (3) the in-situ arc anneal closed the gap down too much so the can was unable to exhaust pressure ahead of the weld. Several operational and mechanical improvements were identified. The weld clamps were changed to a design consistent with those used in the legacy operations. A helium puff operation was eliminated; it is believed that this operation was the cause of the original weld defect. Also, timing of plug mast movement was found to correspond with weld irregularities. The timing of the movement was changed to occur during weld head travel between tacks. In the end a three sequential tack weld process followed by a pulse weld at the same current and travel speed as was used for the legacy processes was suggested for use during the IC qualification effort. Relative to legacy welds, the PDC IC weld demonstrates greater fluctuation in the region of the weld located between tack welds. However, canister weld response (canister to canister) is consistent and with the aid of the optical mapping system (for targeting the cut position) is considered adequate. DR measurements and METs show the PDC IC welds to have sufficient ligament length to ensure adequate canister pressure/impact capacity and to ensure adequate stub function. The PDC welding process has not been optimized as a result of this effort. Differences remain between the legacy BTC welds and the PDC IC weld, but these differences are not sufficient to prevent resumption of the current PDC IC qualification effort. During the PDC IC qualification effort, a total of 17 cans will be welded and a variety of tests/inspections will be performed. The extensive data collected during that qualification effort should be of a sufficient population to determine if additional weld process optimization is necessary prior to production release
Measuring Regenerative Economics: 10 principles and measures undergirding systemic economic health
Applying network science concepts and methods to economic systems is not a new idea. In the last few decades, however, advances in non-equilibrium thermodynamics (i.e., self-organizing, open, dissipative, far-from-equilibrium systems), and nonlinear dynamics, network science, information theory, and other mathematical approaches to complex systems have produced a new set of concepts and methods, which are powerful for understanding and predicting behavior in socio-economic systems. In several previous papers, for example, we used research from the new Energy Network Science (ENS) to show how and why systemic ecological and economic health requires a balance of efficiency and resilience be maintained within a particular a “window of vitality”. The current paper outlines the logic behind 10 principles of systemic, socio-economic health and the quantitative measures that go with them. Our particular focus is on “regenerative aspects”, i.e., the self-feeding, self-renewal, and adaptive learning processes that natural systems use to nourish their capacity to thrive for long periods of time. In socio-economic systems, we demonstrate how regenerative economics requires regular investment in human, social, natural, and physical capital. Taken as a whole, we propose these 10 metrics represent a new capacity to understand, and set better policy for solving, the entangled systemic suite of social, environmental, and economic problems now faced in industrial cultures
Qualitative Human Immunodeficiency Virus RNA Analysis of Dried Blood Spots for Diagnosis of Infections in Infants
The Gen-Probe Aptima human immunodeficiency virus type 1 (HIV-1) RNA assay was adapted for the diagnosis of HIV infection in infants by using dried blood spots. The assay was 99% sensitive (128/129) and 100% specific (162/162). This may prove useful in resource-limited settings, since it precludes the need for a phlebotomist and maintenance of a cold chain
Increased Human Immunodeficiency Virus Type 1 (HIV-1) env Compartmentalization in the Presence of HIV-1-Associated Dementia
The human immunodeficiency virus type 1 (HIV-1) surface Env protein has been implicated in the development of HIV-1-associated dementia (HAD). HIV-1 env diversity was analyzed by heteroduplex tracking assay in 27 infected subjects with various neurological statuses. env compartmentalization between the blood and cerebral spinal fluid (CSF) was apparent with all neurological categories. However, in subjects with HAD, significantly more CSF virus was represented by CNS-unique env variants. Variants specialized for replication in the CNS may play a larger role in the development of HAD. Alternatively, HAD may be associated with a more pronounced state of immunosuppression that permits more extensive replication and independent evolution within the CNS compartment
HIV-1 shedding and chlamydial urethritis [1]
To the Editor.Drs. Schmid and Fontanarosa thoroughly
discussed the causes and management of nongonococcal urethritis.
However, they did not emphasize the link between
treatment of sexually transmitted diseases and prevention of
human immunodeficiency virus (HIV)
Association of CD4 Cell Depletion and Elevated Blood and Seminal Plasma Human Immunodeficiency Virus Type 1 (HIV-1) RNA Concentrations with Genital Ulcer Disease in HIV-1-Infected Men in Malawi
CD4 cell counts and blood plasma and seminal plasma human immunodeficiency virus type 1 (HIV-1) concentrations were compared in HIV-1 RNA-seropositive men with urethritis and with or without genital ulcer disease (GUD). GUD was associated with lower CD4 cell counts (median, 258 vs. 348/μL) and increased blood plasma HIV-1 RNA (median, 240 × 103 vs. 79.4 × 103 copies/ mL). Men with nongonococcal urethritis and GUD shed significantly greater quantities of HIV-1 in semen (median, 195 × 103 vs. 4.0 × 103 copies/mL) than men with nongonococcal urethritis without GUD. These levels decreased ∽4-fold following antibiotic therapy. The results indicate an association between GUD and increased blood HIV-1 RNA levels. Increased HIV-1 in semen was demonstrated in some men with GUD; such an increase could lead to increased transmission, thus complicating interpretation of the role of the genital ulcer itself in the infectiousness of HIV. Reasons for increased HIV RNA in semen in men with GUD remain to be determine
Validation of the Gen-Probe Aptima Qualitative HIV-1 RNA Assay for Diagnosis of Human Immunodeficiency Virus Infection in Infants
The qualitative Roche HIV-1 DNA Amplicor assay has been used for the past 20 years to diagnose HIV infection in infants and young children but is being phased out; hence, alternative assays must be found. The Gen-Probe Aptima qualitative HIV-1 RNA assay is currently the only FDA-cleared HIV-1 nucleic acid assay approved for diagnosis, but data on the use of this assay with infant plasma are limited. We assessed Aptima's performance using control material for reproducibility and limit of detection and 394 plasma samples (0.2 to 0.5 ml) from HIV-exposed infected and uninfected infants and children for analytical sensitivity and specificity. Assays to assess within-run repeatability and between-run reproducibility indicated that the controls with 10,000 (5 of 5), 200 (5 of 5), 100 (16 of 16), 50 (12 of 12), and 25 (20 of 20) HIV-1 RNA copies/ml (cp/ml) were always positive, and negatives were always negative (20 of 20). The limit of detection was 14 cp/ml, as determined by probit analysis. The analytic sensitivity of the assay was 99.5% (189/190 samples; 95% confidence interval [CI], 97.1 to 99.9%) and specificity was 99.5% (199/200 samples; 95% CI, 97.2 to 99.9%). These results suggest that the assay is suitable for early infant diagnosis of HIV-1
Imaging Immune and Metabolic Cells of Visceral Adipose Tissues with Multimodal Nonlinear Optical Microscopy
Visceral adipose tissue (VAT) inflammation is recognized as a mechanism by which obesity is associated with metabolic diseases. The communication between adipose tissue macrophages (ATMs) and adipocytes is important to understanding the interaction between immunity and energy metabolism and its roles in obesity-induced diseases. Yet visualizing adipocytes and macrophages in complex tissues is challenging to standard imaging methods. Here, we describe the use of a multimodal nonlinear optical (NLO) microscope to characterize the composition of VATs of lean and obese mice including adipocytes, macrophages, and collagen fibrils in a label-free manner. We show that lipid metabolism processes such as lipid droplet formation, lipid droplet microvesiculation, and free fatty acids trafficking can be dynamically monitored in macrophages and adipocytes. With its versatility, NLO microscopy should be a powerful imaging tool to complement molecular characterization of the immunity-metabolism interface
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