scholarly journals Influence of mixing height and atmospheric stability conditions on correlation of NO 2 columns and surface concentrations in a Mexico‐United States border region

2021 ◽  
Author(s):  
David E. Flores‐Jiménez ◽  
O. Rafael García‐Cueto ◽  
Néstor Santillán‐Soto ◽  
J. Ernesto López‐Velázquez ◽  
Adriana Camargo‐Bravo
2010 ◽  
Vol 1278 ◽  
Author(s):  
L. E. Rendon ◽  
M. E. Lara ◽  
S. K. Rendon ◽  
M. Rendon ◽  
X. Li

AbstractConcrete biodeterioration is defined as the damage that the products of microorganism metabolism, in particular sulfuric acid, do to hardened concrete. In Canada and in the northern part of the United States, sewer failures from concrete biodeterioration are almost unknown. In the southern part of the United States and in Mexico, however, it is a serious and expensive problem in sewage collection systems, which rapidly deteriorate. Also, leaking sewage systems result in the loss of groundwater resources particularly important in this arid region. Almost every city in the Mexican-American border region, who's combined population is more than 15 million people, faces this problem. The U.S. cities have made some provision to face these infrastructure problems, but the Mexican cities have made less effort. We recommend here the Mexican norm (NMX-C-414-ONNCCE-2004) [1] to be reviewed, or at least that a warning be issued as a key measure to avoid concrete biodeterioration.


2011 ◽  
Vol 28 (7) ◽  
pp. 853-868 ◽  
Author(s):  
A. Sathe ◽  
J. Mann ◽  
J. Gottschall ◽  
M. S. Courtney

Abstract Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model captures the effect of volume illumination and conical scanning. The predictions are compared with the measurements from the ZephIR, WindCube, and sonic anemometers at a flat terrain test site under different atmospheric stability conditions. The sonic measurements are used at several heights on a meteorological mast in combination with lidars that are placed on the ground. Results show that the systematic errors are up to 90% for the vertical velocity variance, whereas they are up to 70% for the horizontal velocity variance. For the ZephIR, the systematic errors increase with height, whereas for the WindCube, they decrease with height. The systematic errors also vary with atmospheric stability and are low for unstable conditions. In general, for both lidars, the model agrees well with the measurements at all heights and under different atmospheric stability conditions. For the ZephIR, the model results are improved when an additional low-pass filter for the 3-s scan is also modeled. It is concluded that with the current measurement configuration, these lidars cannot be used to measure turbulence precisely.


2019 ◽  
Vol 34 (7) ◽  
pp. 1257-1257
Author(s):  
M A Hussain ◽  
L Kamalyan ◽  
M M Diaz ◽  
A Umlauf ◽  
D R Franklin ◽  
...  

Abstract Objective HIV-associated neurocognitive impairment (NCI) is prevalent and impactful. Yet, there is an absence of published studies that investigate its correlates among Spanish-speaking Latinos living in mainland US- a demographic that represents a large and vulnerable segment of the HIV+ population. The goal of the current study was to examine predictors of NCI among Spanish-speaking Latinos with HIV living in the United States. Participants and Method 153 Spanish-speaking Latinos living with HIV from the US-Mexico border region (Age: M = 38.2, SD = 9.7; Education: M = 10.9, SD = 3.6; 73% female; 56% AIDS) completed comprehensive neuropsychological, neuromedical, and psychiatric evaluations in Spanish. Scores across 7 cognitive domains were converted to a Global Deficit Score (GDS) based on T-scores on individual tests using newly developed, region specific, and demographically-corrected norms for Spanish-speaking Latinos. NCI was determined using cutoff of GDS > 0.5 (39.2% of sample). Examined predictors included HIV disease characteristics (e.g., AIDS status, current CD4 count, duration of antiretroviral therapy (ART) exposure) and psychiatric comorbidities. Results A multivariable logistic regression - including predictors that were associated with NCI in univariable analyses - showed a significant interaction between lifetime history of substance use disorder (LT SUD) and duration of ART exposure, after accounting for AIDS status (LR Chi2 = 3.99, p = 0.046). Stratified analyses showed that among participants who did not have LT SUD, longer ART exposure was associated with decreased NCI (p = 0.01), while rates of NCI among those with LT SUD were not influenced by months of ART exposure (p = 0.91). Conclusions Present findings showed that HIV disease burden and psychiatric characteristics might interact to impact NCI among Spanish-speaking Latinos. Considering these influences may help in the provision of comprehensive care to Spanish-speaking, Latino minority groups that suffer from NCI and HIV.


2020 ◽  
pp. 019372352092860
Author(s):  
Jesús Estrada Milán ◽  
Luis Escala Rabadán

This article examines the social and cultural relations that take place in surfing communities on the Mexican side of the border with the United States. Through ethnographic work with surfers from Northern Baja California, we identified different cross-border processes encouraged by this lifestyle sport: the formation of binational surfing communities, commodity circulation, localism, territorial disputes, and shared environmental problems. We point out that surfing on the border creates a system of affinities and rivalries based on the identity and nationalism, marked by the inequality and asymmetry between these two countries. This article also addresses the transnational cooperation and political actions undertaken to protect the oceans and beaches enjoyed by surfers in this border region.


2020 ◽  
pp. 147490412096642
Author(s):  
Jill Koyama

Public education in the United States acts as a governmental tool of neoliberalism, through which state power and sovereignty are deployed and transformed in daily life. Here, I examine how the divergence of sovereignty is exerted over refugee students and their families in US public education. Drawing on 42 months of ethnographic data collected on refugee and other immigrant networks in Southern Arizona, a US–Mexico border region marked by increasing anti-immigrant policies and practices, I reveal how the everyday practices and policies of one school district reflect and reinforce the government’s control over refugee students. I argue that the ways in which the students are sorted, marginalized, and denied opportunities as learners is inextricable from their positioning as non-citizens by the federal and state governments. Specifically, I demonstrate the linkages between the federal education policy, Every School Succeeds Act, Arizona State’s Proposition 203: English Language Education for the Children in Public Schools, which eliminated bilingual education, and the school district’s approach to teaching refugee students. Finally, I offer recommendations for creating more inclusive, assets-based learning environments for refugee students that push back against the neoliberal favoring of competition and one-size-fits-all solutions in public education.


2000 ◽  
Vol 90 (4) ◽  
pp. 742-764 ◽  
Author(s):  
Raymond Robertson

This study uses household-level data from the United States and Mexico to examine labor-market integration. I consider how the effects of shocks and rates of convergence to an equilibrium differential are affected by borders, geography, and demographics. I find that even though a large wage differential exists between them, the labor markets of the United States and Mexico are closely integrated. Mexico's border region is more integrated with the United States than is the Mexican interior. Evidence of integration precedes the North American Free Trade Agreement (NAFTA) and may be largely the result of migration. (JEL F15, F20, J61)


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