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1.
Open Forum Infect Dis ; 10(9): ofad440, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37671088

RESUMO

We performed a scoping review of articles published from 1 January 2000 to 4 January 2022 to characterize inequities in antibiotic prescribing and use across healthcare settings in the United States to inform antibiotic stewardship interventions and research. We included 34 observational studies, 21 cross-sectional survey studies, 4 intervention studies, and 2 systematic reviews. Most studies (55 of 61 [90%]) described the outpatient setting, 3 articles were from dentistry, 2 were from long-term care, and 1 was from acute care. Differences in antibiotic prescribing were found by patient's race and ethnicity, sex, age, socioeconomic factors, geography, clinician's age and specialty, and healthcare setting, with an emphasis on outpatient settings. Few studies assessed stewardship interventions. Clinicians, antibiotic stewardship experts, and health systems should be aware that prescribing behavior varies according to both clinician- and patient-level markers. Prescribing differences likely represent structural inequities; however, no studies reported underlying drivers of inequities in antibiotic prescribing.

2.
Infect Control Hosp Epidemiol ; 44(7): 1085-1092, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36102331

RESUMO

OBJECTIVE: We evaluated the impact of test-order frequency per diarrheal episodes on Clostridioides difficile infection (CDI) incidence estimates in a sample of hospitals at 2 CDC Emerging Infections Program (EIP) sites. DESIGN: Observational survey. SETTING: Inpatients at 5 acute-care hospitals in Rochester, New York, and Atlanta, Georgia, during two 10-workday periods in 2020 and 2021. OUTCOMES: We calculated diarrhea incidence, testing frequency, and CDI positivity (defined as any positive NAAT test) across strata. Predictors of CDI testing and positivity were assessed using modified Poisson regression. Population estimates of incidence using modified Emerging Infections Program methodology were compared between sites using the Mantel-Hanzel summary rate ratio. RESULTS: Surveillance of 38,365 patient days identified 860 diarrhea cases from 107 patient-care units mapped to 26 unique NHSN defined location types. Incidence of diarrhea was 22.4 of 1,000 patient days (medians, 25.8 for Rochester and 16.2 for Atlanta; P < .01). Similar proportions of diarrhea cases were hospital onset (66%) at both sites. Overall, 35% of patients with diarrhea were tested for CDI, but this differed by site: 21% in Rochester and 49% in Atlanta (P < .01). Regression models identified location type (ie, oncology or critical care) and laxative use predictive of CDI test ordering. Adjusting for these factors, CDI testing was 49% less likely in Rochester than Atlanta (adjusted rate ratio, 0.51; 95% confidence interval [CI], 0.40-0.63). Population estimates in Rochester had a 38% lower incidence of CDI than Atlanta (summary rate ratio, 0.62; 95% CI, 0.54-0.71). CONCLUSION: Accounting for patient-specific factors that influence CDI test ordering, differences in testing practices between sites remain and likely contribute to regional differences in surveillance estimates.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Infecção Hospitalar , Humanos , Pacientes Internados , Georgia/epidemiologia , New York/epidemiologia , Hospitais , Diarreia/diagnóstico , Diarreia/epidemiologia , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/epidemiologia , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/epidemiologia , Inquéritos e Questionários
3.
J Phys Chem A ; 126(40): 7309-7330, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36170568

RESUMO

Dark chamber experiments were conducted to study the SOA formed from the oxidation of α-pinene and Δ-carene under different peroxy radical (RO2) fate regimes: RO2 + NO3, RO2 + RO2, and RO2 + HO2. SOA mass yields from α-pinene oxidation were <1 to ∼25% and strongly dependent on available OA mass up to ∼100 µg m-3. The strong yield dependence of α-pinene oxidation is driven by absorptive partitioning to OA and not by available surface area for condensation. Yields from Δ-carene + NO3 were consistently higher, ranging from ∼10-50% with some dependence on OA for <25 µg m-3. Explicit kinetic modeling including vapor wall losses was conducted to enable comparisons across VOC precursors and RO2 fate regimes and to determine atmospherically relevant yields. Furthermore, SOA yields were similar for each monoterpene across the nominal RO2 + NO3, RO2 + RO2, or RO2 + HO2 regimes; thus, the volatility basis sets (VBS) constructed were independent of the chemical regime. Elemental O/C ratios of ∼0.4-0.6 and nitrate/organic mass ratios of ∼0.15 were observed in the particle phase for both monoterpenes in all regimes, using aerosol mass spectrometer (AMS) measurements. An empirical relationship for estimating particle density using AMS-derived elemental ratios, previously reported in the literature for non-nitrate containing OA, was successfully adapted to organic nitrate-rich SOA. Observations from an NO3- chemical ionization mass spectrometer (NO3-CIMS) suggest that Δ-carene more readily forms low-volatility gas-phase highly oxygenated molecules (HOMs) than α-pinene, which primarily forms volatile and semivolatile species, when reacted with NO3, regardless of RO2 regime. The similar Δ-carene SOA yields across regimes, high O/C ratios, and presence of HOMs, suggest that unimolecular and multistep processes such as alkoxy radical isomerization and decomposition may play a role in the formation of SOA from Δ-carene + NO3. The scarcity of peroxide functional groups (on average, 14% of C10 groups carried a peroxide functional group in one test experiment in the RO2 + RO2 regime) appears to rule out a major role for autoxidation and organic peroxide (ROOH, ROOR) formation. The consistently substantially lower SOA yields observed for α-pinene + NO3 suggest such pathways are less available for this precursor. The marked and robust regime-independent difference in SOA yield from two different precursor monoterpenes suggests that in order to accurately model SOA production in forested regions the chemical mechanism must feature some distinction among different monoterpenes.

4.
J Am Med Dir Assoc ; 23(6): 942-946.e1, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35346612

RESUMO

OBJECTIVES: Estimate incidence of and risks for SARS-CoV-2 infection among nursing home staff in the state of Georgia during the 2020-2021 Winter COVID-19 Surge in the United States. DESIGN: Serial survey and serologic testing at 2 time points with 3-month interval exposure assessment. SETTING AND PARTICIPANTS: Fourteen nursing homes in the state of Georgia; 203 contracted or employed staff members from those 14 participating nursing homes who were seronegative at the first time point and provided a serology specimen at second time point, at which time they reported no COVID-19 vaccination or only very recent vaccination (≤4 weeks). METHODS: Interval infection was defined as seroconversion to antibody presence for both nucleocapsid protein and spike protein. We estimated adjusted odds ratios (aORs) and 95% CIs by job type, using multivariable logistic regression, accounting for community-based risks including interval community incidence and interval change in resident infections per bed. RESULTS: Among 203 eligible staff, 72 (35.5%) had evidence of interval infection. In multivariable analysis among unvaccinated staff, staff SARS-CoV-2 infection-induced seroconversion was significantly higher among nurses and certified nursing assistants accounting for race and interval infection incidence in both the community and facility (aOR 5.3, 95% CI 1.0-28.4). This risk persisted but was attenuated when using the full study cohort including those with very recent vaccination. CONCLUSIONS AND IMPLICATIONS: Midway through the first year of the pandemic, job type continues to be associated with increased risk for infection despite enhanced infection prevention efforts including routine screening of staff. These results suggest that mitigation strategies prior to vaccination did not eliminate occupational risk for infection and emphasize critical need to maximize vaccine utilization to eliminate excess risk among front-line providers.


Assuntos
COVID-19 , COVID-19/epidemiologia , Georgia/epidemiologia , Humanos , Casas de Saúde , Pandemias , SARS-CoV-2 , Estados Unidos
5.
Infect Control Hosp Epidemiol ; 43(11): 1664-1671, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35156597

RESUMO

OBJECTIVES: To determine the incidence of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among healthcare personnel (HCP) and to assess occupational risks for SARS-CoV-2 infection. DESIGN: Prospective cohort of healthcare personnel (HCP) followed for 6 months from May through December 2020. SETTING: Large academic healthcare system including 4 hospitals and affiliated clinics in Atlanta, Georgia. PARTICIPANTS: HCP, including those with and without direct patient-care activities, working during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Incident SARS-CoV-2 infections were determined through serologic testing for SARS-CoV-2 IgG at enrollment, at 3 months, and at 6 months. HCP completed monthly surveys regarding occupational activities. Multivariable logistic regression was used to identify occupational factors that increased the risk of SARS-CoV-2 infection. RESULTS: Of the 304 evaluable HCP that were seronegative at enrollment, 26 (9%) seroconverted for SARS-CoV-2 IgG by 6 months. Overall, 219 participants (73%) self-identified as White race, 119 (40%) were nurses, and 121 (40%) worked on inpatient medical-surgical floors. In a multivariable analysis, HCP who identified as Black race were more likely to seroconvert than HCP who identified as White (odds ratio, 4.5; 95% confidence interval, 1.3-14.2). Increased risk for SARS-CoV-2 infection was not identified for any occupational activity, including spending >50% of a typical shift at a patient's bedside, working in a COVID-19 unit, or performing or being present for aerosol-generating procedures (AGPs). CONCLUSIONS: In our study cohort of HCP working in an academic healthcare system, <10% had evidence of SARS-CoV-2 infection over 6 months. No specific occupational activities were identified as increasing risk for SARS-CoV-2 infection.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , SARS-CoV-2 , Pessoal de Saúde , Fatores de Risco , Atenção à Saúde , Imunoglobulina G
6.
Open Forum Infect Dis ; 9(3): ofac034, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35174254

RESUMO

BACKGROUND: Extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales are frequent causes of urinary tract infections (UTIs). Severe infections caused by ESBL Enterobacterales are often treated with carbapenems, but optimal treatment for less severe infections such as UTIs is unclear. METHODS: This retrospective cohort study included patients admitted to 4 hospitals in an academic healthcare system with an ESBL UTI treated with either a noncarbapenem ß-lactam (NCBL) or a carbapenem for at least 48 hours from 1 April 2014 to 30 April 2018. Those who received an NCBL were compared to those receiving a carbapenem, with a primary outcome of hospital length of stay (LOS) and secondary outcomes of clinical and microbiological response, days until transition to oral therapy, rate of relapsed infection, and rate of secondary infections with a multidrug-resistant organism. RESULTS: Characteristics were similar among patients who received carbapenems (n = 321) and NCBLs (n = 171). There was no difference in LOS for the NCBL group compared to the carbapenem group (13 days vs 15 days, P = .66). The NCBL group had higher rates of microbiologic eradication (98% vs 92%, P = .002), shorter time to transition to oral therapy (5 days vs 9 days, P < .001), shorter overall durations of therapy (7 days vs 10 days, P < .001), and lower rates of relapsed infections (5% vs 42%, P = .0003). CONCLUSIONS: Patients treated with NCBLs had similar LOS, higher rates of culture clearance, and shorter durations of antibiotic therapy compared to patients treated with carbapenems, suggesting that treatment for ESBL UTIs should not be selected solely based on phenotypic resistance.

7.
Infect Control Hosp Epidemiol ; 43(3): 381-386, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-33557990

RESUMO

Among 353 healthcare personnel in a longitudinal cohort in 4 hospitals in Atlanta, Georgia (May-June 2020), 23 (6.5%) had severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies. Spending >50% of a typical shift at the bedside (OR, 3.4; 95% CI, 1.2-10.5) and black race (OR, 8.4; 95% CI, 2.7-27.4) were associated with SARS-CoV-2 seropositivity.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/prevenção & controle , Estudos Transversais , Atenção à Saúde , Pessoal de Saúde , Humanos , Fatores de Risco
8.
Artigo em Inglês | MEDLINE | ID: mdl-36168460

RESUMO

Objectives: To estimate prior severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among skilled nursing facility (SNF) staff in the state of Georgia and to identify risk factors for seropositivity as of fall 2020. Design: Baseline survey and seroprevalence of the ongoing longitudinal Coronavirus 2019 (COVID-19) Prevention in Nursing Homes study. Setting: The study included 14 SNFs in the state of Georgia. Participants: In total, 792 SNF staff employed or contracted with participating SNFs were included in this study. The analysis included 749 participants with SARS-CoV-2 serostatus results who provided age, sex, and complete survey information. Methods: We estimated unadjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for potential risk factors and SARS-CoV-2 serostatus. We estimated adjusted ORs using a logistic regression model including age, sex, community case rate, SNF resident infection rate, working at other facilities, and job role. Results: Staff working in high-infection SNFs were twice as likely (unadjusted OR, 2.08; 95% CI, 1.45-3.00) to be seropositive as those in low-infection SNFs. Certified nursing assistants and nurses were 3 times more likely to be seropositive than administrative, pharmacy, or nonresident care staff: unadjusted OR, 2.93 (95% CI, 1.58-5.78) and unadjusted OR, 3.08 (95% CI, 1.66-6.07). Logistic regression yielded similar adjusted ORs. Conclusions: Working at high-infection SNFs was a risk factor for SARS-CoV-2 seropositivity. Even after accounting for resident infections, certified nursing assistants and nurses had a 3-fold higher risk of SARS-CoV-2 seropositivity than nonclinical staff. This knowledge can guide prioritized implementation of safer ways for caregivers to provide necessary care to SNF residents.

9.
JAMA Netw Open ; 3(3): e200396, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32129868

RESUMO

Importance: National Healthcare Safety Network methods for central line-associated bloodstream infection (CLABSI) surveillance do not account for potential additive risk for CLABSI associated with use of 2 central venous catheters (CVCs) at the same time (concurrent CVCs); facilities that serve patients requiring high acuity care with medically indicated concurrent CVC use likely disproportionally incur Centers for Medicare & Medicaid Services payment penalties for higher CLABSI rates. Objective: To quantify the risk for CLABSI associated with concurrent use of a second CVC. Design, Setting, and Participants: This retrospective cohort study included adult patients with 2 or more days with a CVC at 4 geographically separated general acute care hospitals in the Atlanta, Georgia, area that varied in size from 110 to 580 beds, from January 1, 2012, to December 31, 2017. Variables included clinical conditions, central line-days, and concurrent CVC use. Patients were propensity score-matched for likelihood of concurrence (limited to 2 CVCs), and conditional logistic regression modeling was performed to estimate the risk of CLABSI associated with concurrence. Episodes of CVC were categorized as low or high risk and single vs concurrent use to evaluate time to CLABSI with Cox proportional hazards regression models. Data were analyzed from January to June 2019. Exposures: Two CVCs present at the same time. Main Outcomes and Measures: Hospitalizations in which a patient developed a CLABSI, allowing estimation of patient risk for CLABSI and daily hazard for a CVC episode ending in CLABSI. Results: Among a total of 50 254 patients (median [interquartile range] age, 59 [45-69] years; 26 661 [53.1%] women), 64 575 CVCs were used and 647 CLABSIs were recorded. Concurrent CVC use was recorded in 6877 patients (13.7%); the most frequent indications for concurrent CVC use were nutrition (554 patients [14.1%]) or hemodialysis (1706 patients [43.4%]). In the propensity score-matched cohort, 74 of 3932 patients with concurrent CVC use (1.9%) developed CLABSI, compared with 81 of 7864 patients with single CVC use (1.0%). Having 2 CVCs for longer than two-thirds of a patient's CVC use duration was associated with increased likelihood of developing a CLABSI, adjusting for central line-days and comorbidities (adjusted risk ratio, 1.62; 95% CI, 1.10-2.33; P = .001). In survival analysis adjusting for sex, receipt of chemotherapy or total parenteral nutrition, and facility, compared with a single CVC, the daily hazard for 2 low-risk CVCs was 1.78 (95% CI, 1.35-2.34; P < .001), while the daily hazard for 1 low-risk and 1 high-risk CVC was 1.80 (95% CI, 1.42-2.28; P < .001), and the daily hazard for 2 high-risk CVCs was 1.78 (95% CI, 1.14-2.77; P = .01). Conclusions and Relevance: These findings suggest that concurrent CVC use is associated with nearly 2-fold the risk of CLABSI compared with use of a single low-risk CVC. Performance metrics for CLABSI should change to account for variations of this intrinsic patient risk among facilities to reduce biased comparisons and resultant penalties applied to facilities that are caring for more patients with medically indicated concurrent CVC use.


Assuntos
Bacteriemia/epidemiologia , Infecções Relacionadas a Cateter/epidemiologia , Cateterismo Venoso Central/efeitos adversos , Cateterismo Venoso Central/instrumentação , Cateteres Venosos Centrais/efeitos adversos , Idoso , Feminino , Georgia , Humanos , Masculino , Pessoa de Meia-Idade , Pontuação de Propensão , Estudos Retrospectivos
10.
Environ Sci Technol ; 53(5): 2529-2538, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30698424

RESUMO

Biomass burning (BB) is a large source of reactive compounds in the atmosphere. While the daytime photochemistry of BB emissions has been studied in some detail, there has been little focus on nighttime reactions despite the potential for substantial oxidative and heterogeneous chemistry. Here, we present the first analysis of nighttime aircraft intercepts of agricultural BB plumes using observations from the NOAA WP-3D aircraft during the 2013 Southeast Nexus (SENEX) campaign. We use these observations in conjunction with detailed chemical box modeling to investigate the formation and fate of oxidants (NO3, N2O5, O3, and OH) and BB volatile organic compounds (BBVOCs), using emissions representative of agricultural burns (rice straw) and western wildfires (ponderosa pine). Field observations suggest NO3 production was approximately 1 ppbv hr-1, while NO3 and N2O5 were at or below 3 pptv, indicating rapid NO3/N2O5 reactivity. Model analysis shows that >99% of NO3/N2O5 loss is due to BBVOC + NO3 reactions rather than aerosol uptake of N2O5. Nighttime BBVOC oxidation for rice straw and ponderosa pine fires is dominated by NO3 (72, 53%, respectively) but O3 oxidation is significant (25, 43%), leading to roughly 55% overnight depletion of the most reactive BBVOCs and NO2.


Assuntos
Atmosfera , Incêndios , Aerossóis , Aeronaves , Biomassa
11.
Int J Parasitol Parasites Wildl ; 7(3): 301-308, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30128287

RESUMO

Parasite populations are never evenly distributed among the hosts they infect. Avian nest ectoparasites, such as mites, are no exception, as their distribution across the landscape is highly aggregated. It remains unclear if this pattern is driven by differences in transmission events alone, or if the environment that parasites inhabit after transmission also plays a role. Here, we experimentally examined the influence of the post-transmission microclimate, nest characteristics, and host condition on ectoparasite population growth in a bird-ectoparasite system. We infested barn swallow (Hirundo rustica erythrogaster) nests with a standardized number of Northern Fowl Mites (Ornithonyssus sylvarium) and analyzed both biotic (nestling mass, wing length, number of other arthropods present in the nest, and brood size) and abiotic (temperature, humidity, nest lining, nest dimensions, and substrate upon which the nest was built) predictors of mite population growth. Our results suggest that mite populations were most successful, in terms of growth, in nests with higher temperatures, lower humidity, few other arthropods, and hosts in good condition. We also found that nests built on wooden substrates support larger populations of mites than those constructed on metal or concrete. These findings lend insight into the factors that drive large-scale patterns of ectoparasite distributions.

12.
Psychol Rec ; 67(4): 463-471, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29104321

RESUMO

Behavioral momentum theory posits a paradoxical implication for behavioral interventions in clinical situations using Differential Reinforcement of Alternative Behavior (DRA): When alternative reinforcers are presented within the same context as the problem behavior, the added reinforcers may decrease the frequency of the behavior but also increase its persistence when the intervention ends. Providing alternative reinforcers in a setting that is distinctively different from that in which the target behavior occurs may avoid or reduce this increase in persistence. The present experiment compared behavioral persistence following standard DRA versus DRA in a different context that was available after refraining from target behavior (Differential Reinforcement of Other Behavior, DRO). We arranged a human laboratory model of treatment intervention using computer games and token reinforcement. Participants were five individuals with intellectual disabilities. Experimental phases included (a) an initial multiple-schedule baseline with token reinforcement for target behaviors A and B, (b) an intervention phase with alternative reinforcement using a conventional DRA procedure for A and a DRO-DRA procedure for B, and (c) an extinction phase with no interventions and no tokens. Response rates as proportion of baseline in the initial extinction phase were greater for A than for B for three of five participants. Four participants whose response rates remained relatively high during the extinction phase then received a second extinction-plus-distraction test with leisure items available. Response rates were greater for A than for B in three of four participants. The results indicate that DRO-DRA contingencies may contribute to reduced post-intervention persistence of problem behavior.

13.
Environ Sci Technol ; 51(20): 11761-11770, 2017 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-28976736

RESUMO

We report enhancements of glyoxal and methylglyoxal relative to carbon monoxide and formaldehyde in agricultural biomass burning plumes intercepted by the NOAA WP-3D aircraft during the 2013 Southeast Nexus and 2015 Shale Oil and Natural Gas Nexus campaigns. Glyoxal and methylglyoxal were measured using broadband cavity enhanced spectroscopy, which for glyoxal provides a highly selective and sensitive measurement. While enhancement ratios of other species such as methane and formaldehyde were consistent with previous measurements, glyoxal enhancements relative to carbon monoxide averaged 0.0016 ± 0.0009, a factor of 4 lower than values used in global models. Glyoxal enhancements relative to formaldehyde were 30 times lower than previously reported, averaging 0.038 ± 0.02. Several glyoxal loss processes such as photolysis, reactions with hydroxyl radicals, and aerosol uptake were found to be insufficient to explain the lower measured values of glyoxal relative to other biomass burning trace gases, indicating that glyoxal emissions from agricultural biomass burning may be significantly overestimated. Methylglyoxal enhancements were three to six times higher than reported in other recent studies, but spectral interferences from other substituted dicarbyonyls introduce an estimated correction factor of 2 and at least a 25% uncertainty, such that accurate measurements of the enhancements are difficult.


Assuntos
Agroquímicos , Glioxal , Compostos Orgânicos , Aeronaves , Biomassa , Monitoramento Ambiental , Aldeído Pirúvico
14.
Faraday Discuss ; 200: 529-557, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28580969

RESUMO

Cavity enhanced spectroscopy, CES, is a high sensitivity direct absorption method that has seen increasing utility in the last decade, a period also marked by increasing requirements for understanding human impacts on atmospheric composition. This paper describes the current NOAA six channel cavity ring-down spectrometer (CRDS, the most common form of CES) for measurement of nitrogen oxides and O3. It further describes the results from measurements from a tower 300 m above the urban area of Seoul in late spring of 2015. The campaign demonstrates the performance of the CRDS instrument and provides new data on both photochemistry and nighttime chemistry in a major Asian megacity. The instrument provided accurate, high time resolution data for N2O5, NO, NO2, NOy and O3, but suffered from large wall loss in the sampling of NO3, illustrating the requirement for calibration of the NO3 inlet transmission. Both the photochemistry and nighttime chemistry of nitrogen oxides and O3 were rapid in this megacity. Sustained average rates of O3 buildup of 10 ppbv h-1 during recurring morning and early afternoon sea breezes led to a 50 ppbv average daily O3 rise. Nitrate radical production rates, P(NO3), averaged 3-4 ppbv h-1 in late afternoon and early evening, much greater than contemporary data from Los Angeles, a comparable U. S. megacity. These P(NO3) were much smaller than historical data from Los Angeles, however. Nighttime data at 300 m above ground showed considerable variability in high time resolution nitrogen oxide and O3, likely resulting from sampling within gradients in the nighttime boundary layer structure. Apparent nighttime biogenic VOC oxidation rates of several ppbv h-1 were also likely influenced by vertical gradients. Finally, daytime N2O5 mixing ratios of 3-35 pptv were associated with rapid daytime P(NO3) and agreed well with a photochemical steady state calculation.

15.
Environ Sci Technol ; 51(11): 5941-5950, 2017 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-28468492

RESUMO

The Salt Lake Valley experiences severe fine particulate matter pollution episodes in winter during persistent cold-air pools (PCAPs). We employ measurements throughout an entire winter from different elevations to examine the chemical and dynamical processes driving these episodes. Whereas primary pollutants such as NOx and CO were enhanced twofold during PCAPs, O3 concentrations were approximately threefold lower. Atmospheric composition varies strongly with altitude within a PCAP at night with lower NOx and higher oxidants (O3) and oxidized reactive nitrogen (N2O5) aloft. We present observations of N2O5 during PCAPs that provide evidence for its role in cold-pool nitrate formation. Our observations suggest that nighttime and early morning chemistry in the upper levels of a PCAP plays an important role in aerosol nitrate formation. Subsequent daytime mixing enhances surface PM2.5 by dispersing the aerosol throughout the PCAP. As pollutants accumulate and deplete oxidants, nitrate chemistry becomes less active during the later stages of the pollution episodes. This leads to distinct stages of PM2.5 pollution episodes, starting with a period of PM2.5 buildup and followed by a period with plateauing concentrations. We discuss the implications of these findings for mitigation strategies.


Assuntos
Poluentes Atmosféricos , Material Particulado , Temperatura Baixa , Monitoramento Ambiental , Lagos , Utah
16.
J Appl Behav Anal ; 50(1): 87-105, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27861843

RESUMO

Overselective stimulus control refers to discriminative control in which the number of controlling stimuli is too limited for effective behavior. Experiment 1 included 22 special-education students who exhibited overselective stimulus control on a two-sample delayed matching task. An intervention added a compound identity matching opportunity within the sample observation period of the matching trials. The compound matching functioned as a differential observing response (DOR) in that high accuracy verified observation and discrimination of both sample stimuli. Nineteen participants learned to perform the DOR and two-sample delayed matching accuracy increased substantially for 16 of them. When the DOR was completely withdrawn after 10 sessions, accuracy declined. In Experiment 2, a more gradual withdrawal of DOR requirements showed that highly accurate performance could be maintained with the DOR on only a proportion of trials for most participants. The results show that DOR training may lead to a general improvement in observing behavior.


Assuntos
Atenção/fisiologia , Transtorno do Espectro Autista/psicologia , Aprendizagem por Discriminação/fisiologia , Educação Inclusiva/métodos , Deficiência Intelectual/psicologia , Percepção Visual/fisiologia , Adolescente , Criança , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Esquema de Reforço , Adulto Jovem
17.
Am J Intellect Dev Disabil ; 121(3): 219-35, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27119213

RESUMO

Stimulus overselectivity refers to maladaptive narrow attending that is a common learning problem among children with intellectual disabilities and frequently associated with autism. The present study contrasted overselectivity among groups of children with autism, Down syndrome, and typical development. The groups with autism and Down syndrome were matched for intellectual level, and all three groups were matched for developmental levels on tests of nonverbal reasoning and receptive vocabulary. Delayed matching-to-sample tests presented color/form compounds, printed words, photographs of faces, Mayer-Johnson Picture Communication Symbols, and unfamiliar black forms. No significant differences among groups emerged for test accuracy scores. Overselectivity was not statistically overrepresented among individuals with autism in contrast to those with Down syndrome or typically developing children.


Assuntos
Atenção/fisiologia , Transtorno Autístico/fisiopatologia , Desenvolvimento Infantil/fisiologia , Síndrome de Down/fisiopatologia , Reconhecimento Visual de Modelos/fisiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Desempenho Psicomotor , Adulto Jovem
18.
J Appl Behav Anal ; 49(2): 294-307, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26843215

RESUMO

Individuals with developmental disabilities may fail to attend to multiple features in compound stimuli (e.g., arrays of pictures, letters within words) with detrimental effects on learning. Participants were 5 children with autism spectrum disorder who had low to intermediate accuracy scores (35% to 84%) on a computer-presented compound matching task. Sample stimuli were pairs of icons (e.g., chair-tree), the correct comparison was identical to the sample, and each incorrect comparison had one icon in common with the sample (e.g., chair-sun, airplane-tree). A 5-step tabletop sorting-to-matching training procedure was used to teach compound matching. The first step was sorting 3 single pictures; subsequent steps gradually changed the task to compound matching. If progress stalled, tasks were modified temporarily to prompt observing behavior. After tabletop training, participants were retested on the compound matching task; accuracy improved to at least 95% for all children. This procedure illustrates one way to improve attending to multiple features of compound stimuli.


Assuntos
Transtorno Autístico/psicologia , Transtorno Autístico/reabilitação , Aprendizagem por Discriminação/fisiologia , Educação de Pessoa com Deficiência Intelectual , Deficiência Intelectual/psicologia , Deficiência Intelectual/reabilitação , Adolescente , Atenção/fisiologia , Criança , Feminino , Humanos , Masculino , Reconhecimento Visual de Modelos , Estimulação Luminosa , Interface Usuário-Computador
19.
J Appl Behav Anal ; 48(4): 830-44, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26411695

RESUMO

The field of applied behavior analysis emphasizes the importance of conducting functional assessment before treatment development for problem behavior. There is, however, little information regarding the extent to which practitioners are using functional assessment in applied settings for individuals with developmental disabilities (DD). The purpose of the current study was to conduct a survey to assess the degree to which various types of functional assessment are implemented in agencies that serve individuals with DD in Massachusetts. Practitioners were asked to indicate their perception about and use of the various categories of functional assessment (e.g., indirect assessment, descriptive assessment, and functional analysis). From the 205 respondents who completed the survey, the most frequently used functional assessment was descriptive assessment. Results indicated that although the majority (67.8%) of practitioners believe functional analysis to be the most informative assessment tool for selecting behavioral treatment, only 34.6% of respondents indicated that they typically use functional analysis to inform the development of a behavior plan.


Assuntos
Atitude do Pessoal de Saúde , Deficiências do Desenvolvimento , Conhecimentos, Atitudes e Prática em Saúde , Inquéritos e Questionários , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/reabilitação , Escolaridade , Feminino , Humanos , Internet , Masculino , Massachusetts
20.
J Appl Behav Anal ; 48(2): 289-314, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25930176

RESUMO

When inconclusive functional analysis (FA) outcomes occur, a number of modifications have been made to enhance the putative establishing operation or consequence associated with behavioral maintenance. However, a systematic method for identifying relevant events to test during modified FAs has not been evaluated. The purpose of this study was to develop and evaluate a technology for systematically identifying events to test in a modified FA after an initial FA led to inconclusive outcomes. Six individuals, whose initial FA showed little or no responding or high levels only in the control condition, participated. An indirect assessment (IA) questionnaire developed for identifying idiosyncratic variables was administered, and a descriptive analysis (DA) was conducted. Results from the IA only or a combination of the IA and DA were used to inform modified FA test and control conditions. Conclusive FA outcomes were obtained with 5 of the 6 participants during the modified FA phase.


Assuntos
Transtorno do Espectro Autista/psicologia , Terapia Comportamental/métodos , Comportamento Problema/psicologia , Reforço Psicológico , Adolescente , Criança , Humanos , Masculino , Adulto Jovem
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