Cities In USA Research Articles

Understanding angular effects in VHR imagery and their significance for urban land-cover model portability: A study of two multi-angle in-track image sequences

This paper investigates the angular effects causing spectral distortions in multi-angle remote sensing imagery. We study two WorldView-2 multispectral in-track sequences acquired over the cities of Atlanta, USA, and Rio de Janeiro, Brazil, consisting of 13 and 20 co-located images, respectively. The sequences possess off-nadir acquisition angles up to 47.5° and bear markedly different sun-satellite configurations with respect to each other. Both scenes comprise classic urban structures such as buildings of different size, road networks, and parks. First, we quantify the degree of distortion affecting the sequences by means of a non-linear measure of distance between probability distributions, the Maximum Mean Discrepancy. Second, we assess the ability of a classification model trained on an image acquired at a certain view angle to predict the land-cover of all the other images in the sequence. The portability across the sequence is investigated for supervised classifiers of different nature by analyzing the evolution of the classification accuracy with respect to the off-nadir look angle. For both datasets, the effectiveness of physically- and statistically-based normalization methods in obtaining angle-invariant data spaces is compared and synergies are discussed. The empirical results indicate that, after a suitable normalization (histogram matching, atmospheric compensation), the loss in classification accuracy when using a model trained on the near-nadir image to classify the most off-nadir acquisitions can be reduced to as little as 0.06 (Atlanta) or 0.03 (Rio de Janeiro) Kappa points when using a SVM classifier.

Individual variation in ballooning dispersal by black widow spiderlings: The effects of family and social rearing

Abstract Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use behavioral data to understand the ecology and evolution of organisms. Only recently have studies of individual variation in dispersal behavior become a focus of research. A better understanding of individual variation in dispersal behavior is likely to improve our understanding of population dynamics. In particular, the dynamics of critically small populations (endangered species) and large populations (pest species) may be driven by unique dispersal variants. Here we documented individual variation in the ballooning dispersal behavior of Western black widow spiderlings Latrodectus hesperus, an urban pest species found in superabundant infestations throughout cities of the desert Southwest USA. We found a great deal of family-level variation in ballooning dispersal, and this variation was highly consistent (repeatable) across time. Maternal egg investment was a poor predictor of this ballooning dispersal. Instead, we show that spiderlings reared in isolation are significantly slower to disperse than spiderlings raised in a more natural setting surrounded by full siblings. Thus, our study examines a widespread but poorly understood dispersal behavior (ballooning), and suggests urban pest population dynamics are likely driven by the interaction of variation in individuals, families and social environments.

Spatio-temporal characteristics of intra-urban land cover in the cities of China and USA from 1978 to 2010

Urban land cover has major impacts on a city’s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese cities has exhibited a significantly marked difference in comparison with USA cities. This study focused on monitoring and comparing the spatio-temporal dynamics, land cover patterns and characteristics of functional regions in six Chinese (n=3) and USA (n=3) cities. The study data were collated from Landsat TM/MSS imagery during the period 1978–2010. Results indicate that Chinese cities have developed compactly over the past three decades, while development has been notably dispersed among USA cities. Mean vegetation coverage in USA cities is approximately 2.2 times that found amongst Chinese urban agglomerations. Land use types within Chinese cities are significantly more complex, with a higher density of impervious surface area. Conversely, the central business district (CBD) and residential areas within USA cities were comprised of a lower proportion of impervious surface area and a higher proportion of green land. Results may be used to contribute to future urban planning and administration efforts in both China and the USA.

A Random Road Network Model and Its Effects on Topological Characteristics of Mobile Delay-Tolerant Networks

Road networks have significant impact on mobility and network characteristics of wireless ad hoc networks. Discovering their characteristics and effects on mobility and network performance in urban environments is a fundamental research task. In this paper, we firstly study the graph attributes of road networks by sampling real road networks in main cities of Europe and USA. We propose a new graph metric, called characteristic central length , in order to estimate the average shortest-path length of a large-scale spatial network. We find that real road networks from Europe and USA have different patterns with regard to some graph attributes and a simple grid model is inadequate to describe them. Considering the diverse patterns of urban road networks caused by obstacles and shortcuts, we propose a random road network model, called the GRE model. The model is validated through fitting it to real road network samples using a genetic algorithm and simulation of delay-tolerant networks. The simulation results have shown that by extending the grid model with new probabilistic parameters, the GRE model has better capability on approximating real road networks. The simulation results have also shown that delay-tolerant networks operating on road networks may have better performance than scenarios without road networks.

Developing a cancer prevention programme for African-American daughters and mothers

Objective: To describe how nominal group technique was used to inform the development of a breast and cervical cancer awareness programme for African-American adult daughters and mothers. Design: A qualitative approach using nominal group technique. Setting: A mid-sized city in the Southern USA. Method: Nominal group technique was used with 30 African-American daughters (ages 18–35 years) and 19 mothers (mothers of women aged 18–35 years). Daughter groups and mother groups were conducted separately. Responses were tallied and audio recordings were reviewed to provide context and/or clarity to participant responses. Results: In many cases, daughters and mothers had similar thoughts about what African-American women should be aware of, challenges of sharing breast/cervical cancer information between daughter and mother, and thoughts on what would make it easier to share such information. Many responses centred on elements of the communication dynamic between daughters and mothers, rather than specific content messaging about cancer. Recommendations are offered to inform the development of future programmes. Conclusion: Findings illustrate the potential to use upstream intergenerational communication effectively to relay health information between African-American daughters and mothers. Given that breast and cervical cancers have better survival rates when detected and treated early, and that late detection is associated with higher mortality among African-American women, conveying important health-related information from a trusted source (such as an adult daughter) is an important consideration for addressing the cancer prevention and control needs of African-American women.

Possible differences in fetal size by racial origin

In The Lancet Diabetes & Endocrinology, José Villar and colleagues1 describe an international study of fetal ultrasound biometry (widely used to assess fetal growth) through pregnancy, aimed at producing a global standard for fetal growth. The investigators enrolled 4607 pregnant women who were educated, affluent, and healthy—to minimise variation in fetal growth attributable to differences in socioeconomic and environmental status—in cities in Brazil, Italy, Oman, UK, USA, China, India, and Kenya.

Ozone levels in European and USA cities are increasing more than at rural sites, while peak values are decreasing

Ground-level ozone (O3) levels are usually lower in urban centers than nearby rural sites. To compare trends in O3 levels during the period 1990–2010, we obtained monitoring data from paired urban and rural sites from the European Environment Agency and the US Environmental Protection Agency. Ozone peaks decreased at both station types, with no significant differences between urban and rural stations. Ozone annual averages increased at both urban and rural sites, with a faster rate of increase for urban centers. The overall trend was for convergence between urban and rural O3 data. Ozone levels exceeded the criteria established for the protection of human and vegetation health at both urban and rural sites.

Drinking water intake and source patterns within a US–Mexico border population

This study was undertaken to identify water intake and source patterns among a population that resides in a hot, arid region on the US–Mexico border. A cross-sectional community-based survey was conducted among households in the neighbouring cities of El Paso, TX, USA and Ciudad Juárez, Chihuahua, Mexico to obtain data on the quantity and source of water consumed. The study was also designed to identify factors that impact water consumption patterns, including gender, demographics, socio-economic status, cultural characteristics, health status, types of occupations and residences, available water sources and outdoor temperature, among many others. Of all factors studied, outdoor air temperature was found to have the strongest impact upon water intake quantity. Specifically, among the survey participants, when the outdoor air temperature exceeded 90 °F, water consumption increased by 28 %. Additionally, it was found that participants in this region consumed approximately 50 % more water than the values reported in previous studies.

Evaluating the impact of Mexico’s drug policy reforms on people who inject drugs in Tijuana, B.C., Mexico, and San Diego, CA, United States: a binational mixed methods research agenda

BackgroundPolicymakers and researchers seek answers to how liberalized drug policies affect people who inject drugs (PWID). In response to concerns about the failing “war on drugs,” Mexico recently implemented drug policy reforms that partially decriminalized possession of small amounts of drugs for personal use while promoting drug treatment. Recognizing important epidemiologic, policy, and socioeconomic differences between the United States—where possession of any psychoactive drugs without a prescription remains illegal—and Mexico—where possession of small quantities for personal use was partially decriminalized, we sought to assess changes over time in knowledge, attitudes, behaviors, and infectious disease profiles among PWID in the adjacent border cities of San Diego, CA, USA, and Tijuana, Baja California, Mexico.MethodsBased on extensive binational experience and collaboration, from 2012–2014 we initiated two parallel, prospective, mixed methods studies: Proyecto El Cuete IV in Tijuana (n = 785) and the STAHR II Study in San Diego (n = 575). Methods for sampling, recruitment, and data collection were designed to be compatible in both studies. All participants completed quantitative behavioral and geographic assessments and serological testing (HIV in both studies; hepatitis C virus and tuberculosis in STAHR II) at baseline and four semi-annual follow-up visits. Between follow-up assessment visits, subsets of participants completed qualitative interviews to explore contextual factors relating to study aims and other emergent phenomena. Planned analyses include descriptive and inferential statistics for quantitative data, content analysis and other mixed-methods approaches for qualitative data, and phylogenetic analysis of HIV-positive samples to understand cross-border transmission dynamics.ResultsInvestigators and research staff shared preliminary findings across studies to provide feedback on instruments and insights regarding local phenomena. As a result, recruitment and data collection procedures have been implemented successfully, demonstrating the importance of binational collaboration in evaluating the impact of structural-level drug policy reforms on the behaviors, health, and wellbeing of PWID across an international border.ConclusionsOur prospective, mixed methods approach allows each study to be responsive to emerging phenomena within local contexts while regular collaboration promotes sharing insights across studies. The strengths and limitations of this approach may serve as a guide for other evaluations of harm reduction policies internationally.

Further Validation of the Social and Emotional Health Survey for High School Students

The Social Emotional Health Survey (SEHS) was developed with the aim of assessing core cognitive dispositions associated with adolescents’ positive psychosocial development. Using a new sample, the present study sought to extend previous SEHS research by coadministering it with the Behavioral Emotional Screening System (BESS). The sample included 2,240 students in Grades 9-12 from two comprehensive high schools located in a major west coast USA city. A majority of the students were of Latino/a heritage (72 %) and had experienced disadvantaged economic circumstances (80 % at school 1 and 68 % at school 2). Confirmatory factor analyses supported the original SEHS factor structure composed of the first-order constructs of belief-in-self, belief-in-others, emotional competence, and engaged living, which parsimoniously mapped on to a second-order “covitality” factor. Complete factorial invariance was found across four groups formed by crossing gender (male, female) and age (ages 13–15, ages 16–18). Latent means analysis found several small to moderate effects size differences, primarily for the belief-in-self and belief-in-others first-order latent traits. A SEM analysis found that the SEHS measurement model, including covitality was a significant negative predictor of psychological distress as measured by the BESS and was positively associated with students’ end-of-semester grade point average. The discussion focuses on implications for conceptualizing the core psychological components of adolescents’ positive quality of life and how schools can use the SEHS as part of a whole-school procedure to screen for students’ complete mental health.

Comparison of the Estimated Effects of Air Pollution on Human Mortality in Three Southern USA Cities

Background: Researchers have investigated and presented results regarding the impact of air pollution on human mortality for over a decade. We have previously presented and compared results on Atlanta, GA and Birmingham, AL. Aims: We recently began investigating the impact of air pollution on human mortality in Dallas, TX. We present results regarding Dallas, TX and graphically compare the results for all three southern cities: Atlanta, GA, Birmingham, AL and Dallas, TX. We discuss the potential impact of measurement frequency and location sites within a geographic area, as well as imputation methods to create daily air pollution series. Methods: PM2.5, SO2, CO, O3, NO3, and SO4 were measured from monitoring sites within the geographic region encompassing Atlanta, GA, Birmingham, AL and Dallas, TX in varying frequencies and converted to daily average measurements along with daily measurements of temperature and dew point temperature. The relative risk (RR) of mortality due various causes of non-accidental deaths was calculated from results of Poisson regression models with daily deaths as the response variable and daily measurements of air pollution, temperature, dew point, and day-of-week as predictor variables. Models with pollutant lags up to 5 days were investigated using imputed daily series. Results: Positive associations were identified primarily in models with lags up to 1 day for most pollutants within the Atlanta, GA region. We identified few strong positive relationships within the Birmingham, AL region and the Dallas, TX region. Conclusion: The relationship between air pollution and mortality differs by geographic area despite similarities in air pollution concentrations and other atmospheric conditions. This may be due to differences in measurement frequency and imputation techniques to create daily measurements. The models with shorter lags tend to imply the strongest relationships between air pollution concentration and mortality.

Emotional temporal differenceQ‐learning signals in multi‐agent system cooperation: real case studies

Chaotic non-linear dynamics approach is now the most powerful tool for scientists to deal with complexities in real cases; and artificial neural networks and neuro-fuzzy models are widely used for their capabilities in non-linear modelling of chaotic systems. Chaos, uncertain behaviours, demanding fluctuation, complexity of the traffic flow situations and the problems with those methods, however, caused the forecasting traffic flow values to lack robustness and precision. In this study, the traffic flow forecasting is analysed by emotional concepts and multi-agent systems (MASs) points of view as a new method. Its architecture is based on a temporal difference (TD) Q -learning with a neuro-fuzzy structure. The performance of TD Q -learning method is improved by emotional learning. The concept of emotional TD Q -learning method is discussed for the first time in this study. The forecasting algorithm which uses the Q -learning algorithm is capable of finding the optimal forecasting approach as the one obtained by the reinforcement learning. In addition, in order to study in a more practical situation, the neuro-fuzzy behaviours can be modelled by MAS. The real traffic flow signals used for fitting the proposed methods are obtained from interstate I-494 in Minnesota City in USA and the E17 motorway Gent-Antwerp in Belgium.

Pseudomonas aeruginosa isolates of distinct sub-genotypes exhibit similar potential of antimicrobial resistance by drugs exposure

Pseudomonas aeruginosa, a wide-spread opportunistic pathogen, often complicates clinical treatments due to its resistance to a large variety of antimicrobials, especially in immune compromised patients, occasionally leading to death. However, the resistance to antimicrobials varies greatly among the P. aeruginosa isolates, which raises a question on whether some sub-lineages of P. aeruginosa might have greater potential to develop antimicrobial resistance than others. To explore this question, we divided 160 P. aeruginosa isolates collected from cities of USA and China into distinct genotypes using I-CeuI, a special endonuclease that had previously been proven to reveal phylogenetic relationships among bacteria reliably due to the highly conserved 26-bp recognition sequence. We resolved 10 genotypes by I-CeuI analysis and further divided them into 82 sub-genotypes by endonuclease cleavage with SpeI. Eight of the 10 genotypes contained both multi-drug resistant (MDR) and less resistant isolates based on comparisons of their antimicrobial resistance profiles (ARPs). When the less resistant or susceptible isolates from different genotypes were exposed to eight individual antimicrobials, they showed similar potential to become resistant with minor exceptions. This is to our knowledge the first report to examine correlations between phylogenetic sub-lineages of P. aeruginosa and their potential to become resistant to antimicrobials. This study further alerts the importance and urgency of antimicrobial abuse control.

The economic recession and illness

In May 1934, an editorial comment titled, Sickness and the economic depression, was published. This followed a survey hat had recorded illnesses for a three-month period in 1933 and an income and employment record for four years among 12 000 families in 10 USA cities following the Great Depression. The investigators concluded that: “The highest illness rate was reported by a group which was in reasonably comfortable circumstances in 1929, but which had dropped to comparative poverty by 1932”. 1

ANISORROPIA: the adjoint of the aerosol thermodynamic model ISORROPIA

Abstract. We present the development of ANISORROPIA, the discrete adjoint of the ISORROPIA thermodynamic equilibrium model that treats the Na+-SO42−- HSO4−-NH4+ -NO3−-Cl−-H2O aerosol system, and we demonstrate its sensitivity analysis capabilities. ANISORROPIA calculates sensitivities of an inorganic species in aerosol or gas phase with respect to the total concentrations of each species present with less than a two-fold increase in computational time over the concentration calculations. Due to the highly nonlinear and discontinuous solution surface of ISORROPIA, evaluation of the adjoint required a new, complex-variable version of the model, which determines first-order sensitivities with machine precision and avoids cancellation errors arising from finite difference calculations. The adjoint is verified over an atmospherically relevant range of concentrations, temperature, and relative humidity. We apply ANISORROPIA to recent field campaign results from Atlanta, GA, USA, and Mexico City, Mexico, to characterize the inorganic aerosol sensitivities of these distinct urban air masses. The variability in the relationship between fine mode inorganic aerosol mass and precursor concentrations shown has important implications for air quality and climate.

Awareness of, usage of and willingness to use HIV pre-exposure prophylaxis among men in downtown Toronto, Canada

Pre-exposure prophylaxis (PrEP) is a promising strategy whereby HIV-uninfected people could take antiretroviral (ARV) medications to reduce their risk of HIV acquisition. Reports suggest that unsupervised PrEP use has been occurring in gay communities of USA cities before human safety and efficacy data became available. We administered a 20-item questionnaire to men undergoing HIV testing at Hassle Free Clinic, a sexual health clinic in the gay village of Toronto. Questionnaire items enquired about demographics, sexual partners, substance use and awareness of, usage of and willingness to use PrEP. Logistic regression was used to identify characteristics associated with PrEP-related outcomes. Of 256 participants, 11.7% were aware of PrEP, with more men who have sex with men (MSM) aware (14.1%) than non-MSM (4.9%). No participants reported PrEP usage. Willingness to consider PrEP use was high and associated with high-risk activities, suggesting opportunities for PrEP use in the future.

HIV-Infected Late Presenter Patients

HIV-Infected Late Presenter Patients

P2-S3.11 STI-related risk behaviours and STI disparity between residents of Baltimore City and other urban cities in the USA

BackgroundBaltimore City, Maryland, has experienced rates of STDs that are consistently higher than the national average. National surveillance data indicate that in 2000 the rates of gonorrhoea and Chlamydia in...

Urban climate change plans: how holistic?

Urban sustainability issues including climate change mitigation and adaptation, ecological enhancement and livability initiatives have become the rhetorical focus and rationale of many plans and policy documents created by American cities in the last decade. This paper analyses the recent environmentally focused plans for three largest cities of USA to determine how and if their strategies to protect the natural environment engage with the holistic nature of sustainable development strategies promulgated in the literature. Despite the mainstreaming of the sustainability concept, the research shows that these much-lauded and emulated plans largely fail to substantively engage with a fully realised holistic approach, failing to adequately address issues of equitable economic development and environmental justice in their attempts to create a more environmentally sustainable city. The lack of attention paid to such issues suggests not merely that they are perceived as being separate from environmental objectives, but that in some cases they may be seen as oppositional, particularly when contrasted with the way that environmental issues are seen to converge with global city and overall economic development aspirations.

Seroprevalence and correlates of hepatitis A among HIV-negative American men who have sex with men

Hepatitis A outbreaks are well documented among men who have sex with men (MSM). This analysis examines characteristics associated with hepatitis A virus (HAV) infection among a large group of young adult MSM from five USA cities. The Young Men's Survey was a cross-sectional prevalence study of HIV infection and related behavioural risk factors among MSM aged 15-29 years during 1994-2000. Serum specimens from HIV-negative participants were retrospectively tested for antibodies to HAV (anti-HAV). Data were stratified by ethnicity and analysed with logistic regression. Overall anti-HAV prevalence was 18.4% among the 2708 participants, and varied by ethnicity from 6.9 to 45.3% and was highest among Hispanic and Asian men (P < 0.001). Prevalence increased with age across all racial/ethnic groups. Among white men, anti-HAV positivity was associated with having 20 or more lifetime male sex partners for those aged 15-22 years (adjusted odds ratio (AOR)=2.1, 95% confidence interval (CI)=1.0-4.1) and ever having had unprotected anal sex for those aged 23-29 years (AOR=2.4, 95% CI=1.2-4.5). Factors associated with a history of HAV infection among MSM in non-outbreak settings are probably similar to those among non-MSM. MSM are still at risk for HAV infection as a result of outbreaks occurring in MSM communities. Additional studies of hepatitis A vaccination coverage are needed to determine if strategies to vaccinate MSM are adequate.