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1.
Vet Immunol Immunopathol ; 228: 110111, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32846353

ABSTRACT

Salmonella enterica serovar Enteritidis (S. Enteritidis, SE) infection of poultry causes a significant risk to public health through contamination of meat and eggs. Current Salmonella vaccines have failed to provide strong mucosal immunity in the intestines to reduce Salmonella shedding and food contamination. Considering the short lifespan of broilers, an easy-to-deliver, safe and effective Salmonella vaccine is urgently needed. Our goal in this study was to demonstrate the ability of chitosan nanoparticle (CNP) vaccine delivery platform in activating immune response to Salmonella antigens in broilers inoculated orally. In an initial study, soluble whole antigen of SE entrapped in CNP was inoculated but the specific immune responses were poor. Therefore, the CNP entrapped immunogenic outer membrane proteins (OMP) and flagellin (FLA) of SE and surface conjugated with FLA [CNP-(OMP + FLA)] was developed. In broilers inoculated orally with CNP-(OMP + FLA) formulation once or twice, we monitored the temporal expression of innate immune molecules and antigen specific lymphocyte proliferation. In the cecal tonsils of CNP-(OMP + FLA) inoculated birds, we observed enhanced expression of mRNA coding Toll-like receptors (TLRs)- 1, 4, 5, and 7, especially at dpv 21. In addition, both OMP and FLA specific lymphocytes proliferation at dpv 7 and 21 by CNP-(OMP + FLA) were enhanced in the spleen. In conclusion, CNP-(OMP + FLA) formulation augmented both innate and lymphocyte responses in orally inoculated broilers. Further studies are needed to determine the candidate subunit CNP vaccine's efficacy in a challenge trial.


Subject(s)
Adaptive Immunity , Chickens/immunology , Chitosan/immunology , Immunity, Innate , Nanoparticles , Salmonella Vaccines/immunology , Salmonella enteritidis/immunology , Administration, Oral , Animals , Antigens, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Drug Delivery Systems , Flagellin/immunology , RNA, Messenger/metabolism , Toll-Like Receptors/genetics , Toll-Like Receptors/metabolism
2.
Afr J Disabil ; 8: 592, 2019.
Article in English | MEDLINE | ID: mdl-31745462

ABSTRACT

BACKGROUND: While a number of research studies have endeavoured to understand students with disabilities' experience in higher education and have recommended ways to effectively support student success, the role of parental support has been neglected. Many studies have been hampered by a limited understanding of students with disabilities and have, in particular, underestimated students' 'access to economic, social and cultural forms of capital' that caring parents provide. OBJECTIVES: This article seeks to explore students with disabilities' experiences of parental support in the South African higher education context. The research question guiding this article is: What forms of economic, social and cultural capital do parents and extended families provide to students with disabilities to enable them to succeed in higher education? METHOD: In-depth semi-structured individual and focus group interviews were conducted with 17 students with disabilities at two universities of technology. The interview transcripts were thematically analysed with a view to understanding Pierre Bourdieu's forms of capital that parents provided. RESULTS: The study found that while parents are not always able to provide material support, they offered rich and varied forms of social and cultural capital that enabled students with disabilities' academic success. CONCLUSION: Given that parental support plays an important role in the success of students with disabilities, and this role changes as these students become more independent, this study recommends the need for universities to also pay more attention to involving parents in the education of the former. It is hoped that putting in place appropriate forms of parental involvement can create a conducive environment for universities to provide inclusive education holistically.

3.
Nature ; 527(7577): 208-11, 2015 Nov 12.
Article in English | MEDLINE | ID: mdl-26524533

ABSTRACT

To advance quantum information science, physical systems are sought that meet the stringent requirements for creating and preserving quantum entanglement. In atomic physics, robust two-qubit entanglement is typically achieved by strong, long-range interactions in the form of either Coulomb interactions between ions or dipolar interactions between Rydberg atoms. Although such interactions allow fast quantum gates, the interacting atoms must overcome the associated coupling to the environment and cross-talk among qubits. Local interactions, such as those requiring substantial wavefunction overlap, can alleviate these detrimental effects; however, such interactions present a new challenge: to distribute entanglement, qubits must be transported, merged for interaction, and then isolated for storage and subsequent operations. Here we show how, using a mobile optical tweezer, it is possible to prepare and locally entangle two ultracold neutral atoms, and then separate them while preserving their entanglement. Ground-state neutral atom experiments have measured dynamics consistent with spin entanglement, and have detected entanglement with macroscopic observables; we are now able to demonstrate position-resolved two-particle coherence via application of a local gradient and parity measurements. This new entanglement-verification protocol could be applied to arbitrary spin-entangled states of spatially separated atoms. The local entangling operation is achieved via spin-exchange interactions, and quantum tunnelling is used to combine and separate atoms. These techniques provide a framework for dynamically entangling remote qubits via local operations within a large-scale quantum register.

4.
Science ; 345(6194): 306-9, 2014 Jul 18.
Article in English | MEDLINE | ID: mdl-24968938

ABSTRACT

The quantum statistics of atoms is typically observed in the behavior of an ensemble via macroscopic observables. However, quantum statistics modifies the behavior of even two particles. Here, we demonstrate near-complete control over all the internal and external degrees of freedom of two laser-cooled (87)Rb atoms trapped in two optical tweezers. This controllability allows us to observe signatures of indistinguishability via two-particle interference. Our work establishes laser-cooled atoms in optical tweezers as a promising route to bottom-up engineering of scalable, low-entropy quantum systems.

5.
J Neuropsychiatry Clin Neurosci ; 25(2): 115-9, 2013.
Article in English | MEDLINE | ID: mdl-23686028

ABSTRACT

The author collected and analyzed data for all student-athletes diagnosed with concussion between 1998 and 2011. Outcome measurements were post-concussion symptom duration, time interval until return-to-play, and clinical outcomes self-reported by athletes and by athlete's parent/guardian 1 year post-injury. A total of 98 concussions occurred in 95 student athletes among a cohort averaging 350 athletes competing yearly. Athletes were managed according to expert-consensus guidelines. Forty-one (43%) of the athletes had experienced a previously-diagnosed concussion (range: 1-3). Eight athletes (10.4%), retired from their sport for concussion-related issues. Six athletes (6.3%) with completed follow-up experienced memory and/or concentration impairment(s) lasting more than 1 year.


Subject(s)
Athletic Injuries/complications , Athletic Injuries/epidemiology , Brain Concussion/epidemiology , Brain Concussion/etiology , Adolescent , Brain Concussion/diagnosis , Cohort Studies , Female , Humans , Male , Outcome Assessment, Health Care , Retrospective Studies , Students , Young Adult
6.
Environ Sci Technol ; 47(6): 2502-11, 2013 Mar 19.
Article in English | MEDLINE | ID: mdl-23398047

ABSTRACT

There is growing interest in reducing energy use and emissions of carbon dioxide from the residential sector by deploying cost-effectiveness energy efficiency measures. However, there is still large uncertainty about the magnitude of the reductions that could be achieved by pursuing different energy efficiency measures across the nation. Using detailed estimates of the current inventory and performance of major appliances in U.S. homes, we model the cost, energy, and CO2 emissions reduction if they were replaced with alternatives that consume less energy or emit less CO2. We explore trade-offs between reducing CO2, reducing primary or final energy, or electricity consumption. We explore switching between electricity and direct fuel use, and among fuels. The trade-offs between different energy efficiency policy goals, as well as the environmental metrics used, are important but have been largely unexplored by previous energy modelers and policy-makers. We find that overnight replacement of the full stock of major residential appliances sets an upper bound of just over 710 × 10(6) tonnes/year of CO2 or a 56% reduction from baseline residential emissions. However, a policy designed instead to minimize primary energy consumption instead of CO2 emissions will achieve a 48% reduction in annual carbon dioxide emissions from the nine largest energy consuming residential end-uses. Thus, we explore the uncertainty regarding the main assumptions and different policy goals in a detailed sensitivity analysis.


Subject(s)
Carbon Dioxide/analysis , Carbon Footprint/economics , Environmental Policy/economics , Electricity , United States
7.
J Dev Orig Health Dis ; 3(6): 395-408, 2012 Dec.
Article in English | MEDLINE | ID: mdl-25084292

ABSTRACT

Advances in understanding the molecular basis of behavior through epigenetic mechanisms could help explain the developmental origins of child mental health disorders. However, the application of epigenetic principles to the study of human behavior is a relatively new endeavor. In this paper we discuss the 'Developmental Origins of Health and Disease' including the role of fetal programming. We then review epigenetic principles related to fetal programming and the recent application of epigenetics to behavior. We focus on the neuroendocrine system and develop a simple heuristic stress-related model to illustrate how epigenetic changes in placental genes could predispose the infant to neurobehavioral profiles that interact with postnatal environmental factors potentially leading to mental health disorders. We then discuss from an 'Evo-Devo' perspective how some of these behaviors could also be adaptive. We suggest how elucidation of these mechanisms can help to better define risk and protective factors and populations at risk.


Subject(s)
Epigenesis, Genetic , Mental Disorders/genetics , 11-beta-Hydroxysteroid Dehydrogenase Type 2/genetics , Child , Fetal Development , Humans , Mental Disorders/etiology , Neurosecretory Systems/physiology , Polymorphism, Single Nucleotide
8.
J Clin Exp Neuropsychol ; 34(3): 235-42, 2012.
Article in English | MEDLINE | ID: mdl-22149547

ABSTRACT

Computerized neuropsychological testing is commonly utilized in the management of sport-related concussion. In particular, the Immediate Postconcussion Assessment and Cognitive Testing 2.0 program (ImPACT) is widely used to assess the cognitive functioning of athletes before and after a concussion. We review the evidence for the clinical utility of this program in terms of validity, reliability, and use in return-to-play decisions. We conclude that the empirical evidence does not support the use of ImPACT testing for determining the time of postconcussion return to play.


Subject(s)
Athletic Injuries/psychology , Brain Concussion/psychology , Recovery of Function/physiology , Athletic Injuries/complications , Brain Concussion/etiology , Humans , Male , Neuropsychological Tests , Psychometrics , Reproducibility of Results
9.
Proc Natl Acad Sci U S A ; 108(40): 16554-8, 2011 Oct 04.
Article in English | MEDLINE | ID: mdl-21949359

ABSTRACT

We assess the economic value of life-cycle air emissions and oil consumption from conventional vehicles, hybrid-electric vehicles (HEVs), plug-in hybrid-electric vehicles (PHEVs), and battery electric vehicles in the US. We find that plug-in vehicles may reduce or increase externality costs relative to grid-independent HEVs, depending largely on greenhouse gas and SO(2) emissions produced during vehicle charging and battery manufacturing. However, even if future marginal damages from emissions of battery and electricity production drop dramatically, the damage reduction potential of plug-in vehicles remains small compared to ownership cost. As such, to offer a socially efficient approach to emissions and oil consumption reduction, lifetime cost of plug-in vehicles must be competitive with HEVs. Current subsidies intended to encourage sales of plug-in vehicles with large capacity battery packs exceed our externality estimates considerably, and taxes that optimally correct for externality damages would not close the gap in ownership cost. In contrast, HEVs and PHEVs with small battery packs reduce externality damages at low (or no) additional cost over their lifetime. Although large battery packs allow vehicles to travel longer distances using electricity instead of gasoline, large packs are more expensive, heavier, and more emissions intensive to produce, with lower utilization factors, greater charging infrastructure requirements, and life-cycle implications that are more sensitive to uncertain, time-sensitive, and location-specific factors. To reduce air emission and oil dependency impacts from passenger vehicles, strategies to promote adoption of HEVs and PHEVs with small battery packs offer more social benefits per dollar spent.


Subject(s)
Air Pollutants/analysis , Automobiles/economics , Electric Power Supplies , Vehicle Emissions/analysis , Conservation of Energy Resources , Greenhouse Effect
10.
J Perinatol ; 31(11): 711-6, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21415836

ABSTRACT

OBJECTIVE: The objective of this study was to assess the predictive value of body mass index (BMI) at earlier ages on risk of overweight/obesity at age of 11 years. STUDY DESIGN: This is a longitudinal study of 907 children from birth to age of 11 years. Predictors include BMI at earlier ages and outcome is overweight/obesity status at age of 11 years. Analyses were adjusted for covariates known to affect BMI. RESULT: At 11 years, 17% were overweight and 25% were obese. Children whose BMI was measured as ≥85th percentile once at preschool age had a twofold risk for overweight/obesity at 11 years of age. Risk increased by 11-fold if a child's BMI measured was noted more than once during this age. During early elementary years, if a child's BMI was>85th percentile once, risk for overweight/obesity at 11 years was fivefold and increased by 72-fold if noted more than two times. During late elementary years, if a child's BMI was>85th percentile once, risk for overweight/obesity was 26-fold and increased by 351-fold if noted more than two times. Risk of overweight/obesity at 11 years was noted with higher maternal prepregnancy weight, higher birth weight, female gender and increased television viewing. CONCLUSION: Children in higher BMI categories at young ages have a higher risk of overweight/obesity at 11 years of age. Effect size was greater for measurements taken closer to 11 years of age. Pediatricians need to identify children at-risk for adolescent obesity and initiate counseling and intervention at earlier ages.


Subject(s)
Obesity/etiology , Body Mass Index , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Longitudinal Studies , Male , Overweight/etiology , Risk Factors
11.
J Clin Exp Neuropsychol ; 33(5): 532-7, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21218317

ABSTRACT

OBJECTIVE: To measure working memory capacity among a cohort of collegiate athletes and to compare results between athletes competing in head-contact-prone sports with those not subject to repeated head contacts. A secondary objective was to determine the effect of sport-related concussion on working memory capacity. DESIGN: Ambidirectional cohort study. SETTING: Athletics department at an American university. PARTICIPANTS: Student athletes competing in various sports. INTERVENTIONS: None. MAIN OUTCOME MEASUREMENT: Automated operation span test scores. RESULTS: Working memory capacity is not impaired in student athletes who participate in head-contact-prone sports or in student athletes with a history of diagnosed concussion, even those who are multiconcussed. Our results suggest that athletes competing in sports that impose significant working memory loading score higher on the automated operation span test than do other athletes. CONCLUSIONS: Further research is required to determine the value of measuring working memory capacity in acutely concussed, symptomatic athletes.


Subject(s)
Brain Concussion/complications , Memory Disorders/diagnosis , Memory Disorders/etiology , Memory, Short-Term/physiology , Athletes/psychology , Cohort Studies , Female , Humans , Male , Neuropsychological Tests , Students/psychology , Universities
12.
Infect Dis Rep ; 3(2): e12, 2011 Sep 07.
Article in English | MEDLINE | ID: mdl-24470909

ABSTRACT

Invasive aspergillosis is an often fatal disease that usually occurs in immunocompromised patients. We report a case of invasive aspergillosis presenting as a febrile respiratory infection with a cardiac mass in an immunocompetent patient. Invasive asper-gillosis should be considered in the differential diagnosis of an otherwise undiagnosed invasive febrile respiratory illness, even in immunocompetent patients. Echocardiography should be performed to evaluate for endocarditis in such cases. Prompt initiation of appropriate antifungal therapy is warranted, even before the diagnosis of invasive aspergillosis is confirmed.

13.
J Air Waste Manag Assoc ; 60(5): 523-31, 2010 May.
Article in English | MEDLINE | ID: mdl-20480851

ABSTRACT

Generators installed for backup power during blackouts could help satisfy peak electricity demand; however, many are diesel generators with nonnegligible air emissions that may damage air quality and human health. The full (private and social) cost of using diesel generators with and without emission control retrofits for fine particulate matter (PM2.5) and nitrogen oxides (NOx) were compared with a new natural gas turbine peaking plant. Lower private costs were found for the backup generators because the capital costs are mostly ascribed to reliability. To estimate the social costs from air quality, the changes in ambient concentrations of ozone (O3) and PM2.5 were modeled using the Particulate Matter Comprehensive Air Quality Model with extensions (PMCAMx) chemical transport model. These air quality changes were translated to their equivalent human health effects using concentration-response functions and then into dollars using estimates of "willingness-to-pay" to avoid ill health. As a case study, 1000 MW of backup generation operating for 12 hr/day for 6 days in each of four eastern U.S. cities (Atlanta, Chicago, Dallas, and New York) was modeled. In all cities, modeled PM2.5 concentrations increased (up to 5 microg/m3) due mainly to primary emissions. Smaller increases and decreases were observed for secondary PM2.5 with more variation between cities. Increases in NOx, emissions resulted in significant nitrate formation (up to 1 microg/m3) in Atlanta and Chicago. The NOx emissions also caused O3 decreases in the urban centers and increases in the surrounding areas. For PM2.5, a social cost of approximately $2/kWh was calculated for uncontrolled diesel generators in highly populated cities but was under 10 cent/kWh with PM2.5 and NOx controls. On a full cost basis, it was found that properly controlled diesel generators are cost-effective for meeting peak electricity demand. The authors recommend NOx and PM2.5 controls.


Subject(s)
Air Pollutants, Occupational/adverse effects , Air Pollutants, Occupational/economics , Power Plants , Air Pollutants, Occupational/analysis , Endpoint Determination , Environmental Monitoring , Gasoline , Humans , Nitrogen Oxides/analysis , Nitrogen Oxides/economics , Public Health
14.
Environ Sci Technol ; 43(20): 7619-25, 2009 Oct 15.
Article in English | MEDLINE | ID: mdl-19921870

ABSTRACT

We model alternatives for moving bulk energy, including both private costs and accounting for environmental externalities by requiring the transport system to satisfy environment health, and safety standards. In particular, we focus on the cost and environmental trade-offs between "coal by wire," mine-mouth generation with electricity transmission, and transporting the primary energy resources with generation near the customer. Having the bulk energy transport model satisfy standards avoids the controversy associated with estimating dollar costs for constrained visibility, noise, and 50/60 Hz electromagnetic fields. A sensitivity analysis examines the implications of a range of carbon-dioxide discharge charges.


Subject(s)
Energy-Generating Resources , Models, Economic , Transportation , Costs and Cost Analysis
15.
Environ Sci Technol ; 42(9): 3139-44, 2008 May 01.
Article in English | MEDLINE | ID: mdl-18522086

ABSTRACT

The price of delivered electricity will rise if generators have to pay for carbon dioxide emissions through an implicit or explicit mechanism. There are two main effects that a substantial price on CO2 emissions would have in the short run (before the generation fleet changes significantly). First, consumers would react to increased price by buying less, described by their price elasticity of demand. Second, a price on CO2 emissions would change the order in which existing generators are economically dispatched, depending on their carbon dioxide emissions and marginal fuel prices. Both the price increase and dispatch changes depend on the mix of generation technologies and fuels in the region available for dispatch, although the consumer response to higher prices is the dominant effect. We estimate that the instantaneous imposition of a price of $35 per metric ton on CO2 emissions would lead to a 10% reduction in CO2 emissions in PJM and MISO at a price elasticity of -0.1. Reductions in ERCOT would be about one-third as large. Thus, a price on CO2 emissions that has been shown in earlier workto stimulate investment in new generation technology also provides significant CO2 reductions before new technology is deployed at large scale.


Subject(s)
Air Pollution/economics , Carbon Dioxide/analysis , Conservation of Natural Resources/economics , Environment , Greenhouse Effect , Industrial Waste/economics , Air Pollution/analysis , Air Pollution/legislation & jurisprudence , Conservation of Natural Resources/legislation & jurisprudence , Economics , Gases , Industrial Waste/analysis , Industrial Waste/legislation & jurisprudence , Industry , Models, Economic , Public Policy , United States
16.
J Adolesc Health ; 42(2): 201-3, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18207100

ABSTRACT

PURPOSE: To survey the prevalence of body art and incidence of medical complications among university students comparing results in 2001 and 2006. METHODS: Students reported body piercings and tattoos and occurrence of medical complications. RESULTS: Prevalence of body piercing was 51% and tattooing 22%. Piercing medical complication incidence was 19%. No tattooing medical complications occurred. CONCLUSIONS: Body art is prevalent among undergraduate university students, with prevalence essentially unchanged during two consecutive 5-year samples. Medical complications occur frequently among those with piercings.


Subject(s)
Bacterial Infections/epidemiology , Body Piercing/statistics & numerical data , Risk-Taking , Students/statistics & numerical data , Tattooing/statistics & numerical data , Adolescent , Adolescent Behavior , Adult , Age Distribution , Bacterial Infections/etiology , Body Piercing/adverse effects , Cross-Sectional Studies , Female , Forecasting , Humans , Incidence , Male , Probability , Sex Distribution , Tattooing/adverse effects , Time Factors , Universities
17.
S Afr J Surg ; 45(4): 136-8, 140, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18069581

ABSTRACT

OBJECTIVE: Historically, lymphoepithelial lesions (LELs) have been a peripheral indication for surgery on the parotid gland, accounting for less than 1% of all parotidectomies undertaken. In the HIV era the profile of parotidectomy has changed, with LEL becoming a common indication for parotidectomy, prompting a review of our current experience. DESIGN: A retrospective study was undertaken between January 1998 and December 2005. Setting. Surgical services at King Edward VIII Hospital, Durban. SUBJECTS: All patients presenting with parotidomegaly. RESULTS: One hundred and sixty-two patients with parotidomegaly were evaluated; 53 (32.7%) had LEL lesions. A total of 151 parotidectomies (including 42 parotidectomies undertaken for LEL lesions) were performed in 147 patients. Radiotherapy was offered to 11 patients with LEL lesions. Complications following parotidectomy for LEL included facial nerve palsy (N=3), seroma formation (N=5) and facial artery false aneurysm (N=1). Three patients required re-parotidectomy for recurrent LEL parotidomegaly. In the patients who underwent radiotherapy, there was a satisfactory outcome; 2 patients who received 4 Gy radiation per sitting developed mild skin discolouration of the treated area. CONCLUSION: Although surgical management of LEL parotidomegaly may provide a satisfactory result, this approach is technically challenging and is associated with complications and recurrences. For these reasons, the non-operative approach employing radiotherapy should be considered.


Subject(s)
Epithelium/pathology , HIV Infections/physiopathology , Lymph Nodes/pathology , Parotid Diseases/surgery , Parotid Gland/pathology , Adolescent , Adult , Child , Child, Preschool , Female , HIV Infections/complications , HIV Infections/pathology , Humans , Male , Middle Aged , Parotid Diseases/etiology , Parotid Diseases/pathology , Retrospective Studies , South Africa
18.
Surg Laparosc Endosc Percutan Tech ; 17(5): 385-7, 2007 Oct.
Article in English | MEDLINE | ID: mdl-18049397

ABSTRACT

Iatrogenic splenic injury requiring splenectomy is a well-recognized and potentially serious complication of colon resection. Iatrogenic splenectomy is associated with significant morbidity and mortality, including bleeding and the postsplenectomy sepsis syndrome. Our study aims to compare the incidence of iatrogenic splenectomy in laparoscopic colon resection with that of open colon resection over an 11-year-period at Mount Sinai. A retrospective chart review of all patients undergoing colon resection at Mount Sinai Medical Center during the last 11 years was performed to identify patient demographics, procedure, indication, and outcome. There was a significant difference (P=0.03) in the incidence of iatrogenic splenectomy during open colectomy (13/5477, 0.24%) versus laparoscopic colectomy (0/1911, 0%). All cases complicated by iatrogenic splenectomy involved splenic flexure mobilization. Laparoscopy has many recognized advantages over open procedures, including shorter recovery and length of stay. This retrospective review of our experience at Mount Sinai presents another potential benefit of the laparoscopic approach to colon resection.


Subject(s)
Colectomy/adverse effects , Laparoscopy/adverse effects , Spleen/injuries , Splenectomy/methods , Aged , Aged, 80 and over , Colectomy/methods , Colonic Diseases/surgery , Female , Follow-Up Studies , Humans , Iatrogenic Disease , Male , Middle Aged , Prognosis , Retrospective Studies , Rupture
19.
Environ Sci Technol ; 41(10): 3431-6, 2007 May 15.
Article in English | MEDLINE | ID: mdl-17547159

ABSTRACT

More than 50% of electricity in the U.S. is generated by coal. The U.S. has large coal resources, the cheapest fuel in most areas. Coal fired power plants are likely to continue to provide much of U.S. electricity. However, the type of power plant that should be built is unclear. Technology can reduce pollutant discharges and capture and sequester the CO2 from coal-fired generation. The U.S. Energy Policy Act of 2005 provides incentives for large scale commercial deployment of Integrated Coal Gasification Combined Cycle (IGCC) systems (e.g., loan guarantees and project tax credits). This analysis examines whether a new coal plant should be Pulverized Coal (PC) or IGCC. Do stricter emissions standards (PM, SO2, NOx, Hg) justify the higher costs of IGCC over PC? How does potential future carbon legislation affect the decision to add carbon capture and storage (CCS) technology? Finally, can the impact of uncertain carbon legislation be minimized? We find that SO2, NOx, PM, and Hg emission standards would have to be far more stringent than twice current standards to justify the increased costs of the IGCC system. A C02 tax less than $29/ton would lead companies to continuing to choose PC, paying the tax for emitted CO2. The earlier a decision-maker believes the carbon tax will be imposed and the higher the tax, the more likely companies will choose IGCC w/CCS. Having government announce the date and level of a carbon tax would promote more sensible decisions, but government would have to use a tax or subsidy to induce companies to choose the technology that is best for society.


Subject(s)
Carbon , Coal/economics , Legislation as Topic , Electricity , Environmental Pollution/legislation & jurisprudence , Power Plants/economics
20.
Environ Sci Technol ; 40(22): 6887-93, 2006 Nov 15.
Article in English | MEDLINE | ID: mdl-17153991

ABSTRACT

Existing generators installed for backup during blackouts could be operated during periods of peak electricity demand, increasing grid reliability and supporting electricity delivery. Many generators, however, have non-negligible air emissions and may potentially damage air quality and harm human health. To evaluate using these generators, we compare the levelized private and social (health) costs of diesel internal combustion engines (ICE) with and without diesel particulate filters (DPF), natural gas ICEs, and microturbines to a new peaking plant in New York, NY. To estimate the social cost, first we calculate the upper range emissions for each generator option from producing 36,000 megawatt-hours (MWh) of electricity over 3 days. We then convert the emissions into ambient concentrations with a 3-D chemical transport model, PMCAMx, and Gaussian dispersion plumes. Using a Monte Carlo approach to incorporate the uncertainties, we calculate the health endpoints using concentration-response functions and multiply the response by its economic value. While uncontrolled diesel ICEs would harm air quality and health, a generator with a DPF has a social cost, comparable to natural gas options. We conclude on a full cost basis that backup generators, including controlled diesel ICEs, are a cost-effective method of meeting peak demand.


Subject(s)
Power Plants/economics , Power Plants/standards , Air Pollution/prevention & control , Costs and Cost Analysis , Electricity , Energy-Generating Resources/standards , Environmental Health/economics , Environmental Health/standards , Humans , Monte Carlo Method , Power Plants/instrumentation
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