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result(s) for
"La Luna, Anthony"
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Scattering properties and lidar characteristics of Asian dust particles based on realistic shape models
2025
The lidar backscattering properties of Asian dust particles, namely the lidar ratio (S) and backscattering depolarization ratio (δ), were studied using a discrete dipole approximation (DDA) model. The three-dimensional morphology of the dust particles was reconstructed in fine detail using the focused ion beam (FIB) tomography technique. An index based on the symmetry of the scattering matrix was developed to assess the convergence of random orientation computation using DDA. Both S and δ exhibit an asymptotic trend with dust particle size: the S initially decreases, while the δ increases with size, before both approach their asymptotic values. The lidar properties were found to have statistically insignificant dependence on effective sphericity. The presence of strongly absorbing minerals, such as magnetite, can greatly reduce the dust's single-scattering albedo and δ. Utilizing the robust asymptotic trend behavior, two parameterization schemes were developed: one to estimate the δ of a single dust particle given its size and the other to estimate the δ of dust particles with a lognormal particle size distribution given the effective radius. The parameterization scheme was compared with results based on the TAMUdust2020 database, showing hexahedrons to reasonably represent realistic geometries with similar physical properties.
Journal Article
Treponema pallidum genetic diversity and its implications for targeted vaccine development: A cross-sectional study of early syphilis cases in Southwestern Colombia
by
Martínez-Valencia, Alvaro J.
,
Parr, Jonathan B.
,
Ramirez, Jose D.
in
Adult
,
Animals
,
Antibiotics
2024
Venereal syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), is surging worldwide, underscoring the need for a vaccine with global efficacy. Vaccine development requires an understanding of syphilis epidemiology and clinical presentation as well as genomic characterization of TPA strains circulating within at-risk populations. The aim of this study was to describe the clinical, demographic, and molecular features of early syphilis cases in Cali, Colombia.
We conducted a cross-sectional study to identify individuals with early syphilis (ES) in Cali, Colombia through a city-wide network of public health centers, private sector HIV clinics and laboratory databases from public health institutions. Whole blood (WB), skin biopsies (SB), and genital and oral lesion swabs were obtained for measurement of treponemal burdens by polA quantitative polymerase chain reaction (qPCR) and for whole-genome sequencing (WGS). Among 1,966 individuals screened, 128 participants met enrollment criteria: 112 (87%) with secondary (SS), 15 (12%) with primary (PS) and one with early latent syphilis; 66/128 (52%) self-reported as heterosexual, while 48 (38%) were men who have sex with men (MSM). Genital ulcer swabs had the highest polA copy numbers (67 copies/μl) by qPCR with a positivity rate (PR) of 73%, while SS lesions had 42 polA copies/μl with PR of 62%. WB polA positivity was more frequent in SS than PS (42% vs 7%, respectively; p = 0.009). Isolation of TPA from WB by rabbit infectivity testing (RIT) was achieved in 5 (56%) of 9 ES WB samples tested. WGS from 33 Cali patient samples, along with 10 other genomic sequences from South America (9 from Peru, 1 from Argentina) used as comparators, confirmed that SS14 was the predominant clade, and that half of all samples had mutations associated with macrolide (i.e., azithromycin) resistance. Variability in the outer membrane protein (OMP) and vaccine candidate BamA (TP0326) was mapped onto the protein's predicted structure from AlphaFold. Despite the presence of mutations in several extracellular loops (ECLs), ECL4, an immunodominant loop and proven opsonic target, was highly conserved in this group of Colombian and South American TPA isolates.
This study offers new insights into the sociodemographic and clinical features of venereal syphilis in a highly endemic area of Colombia and illustrates how genomic sequencing of regionally prevalent TPA strains can inform vaccine development.
Journal Article
Monetary Intelligence and Behavioral Economics: The Enron Effect—Love of Money, Corporate Ethical Values, Corruption Perceptions Index (CPI), and Dishonesty Across 31 Geopolitical Entities
by
Ansari, Mahfooz A.
,
Kazem, Ali Mahdi
,
Chen, Jingqiu
in
Attitudes
,
Behavioral economics
,
Business and Management
2018
Monetary intelligence theory asserts that individuals apply their money attitude to frame critical concerns in the context and strategically select certain options to achieve financial goals and ultimate happiness. This study explores the dark side of monetary Intelligence and behavioral economics—dishonesty (corruption). Dishonesty, a risky prospect, involves cost-benefit analysis of self-interest. We frame good or bad barrels in the environmental context as a proxy of high or low probability of getting caught for dishonesty, respectively. We theorize: The magnitude and intensity of the relationship between love of money and dishonest prospect (dishonesty) may reveal how individuals frame dishonesty in the context of two levels of subjective norm—perceived corporate ethical values at the micro-level (CEV, Level 1) and Corruption Perceptions Index at the macro-level (CPI, Level 2), collected from multiple sources. Based on 6382 managers in 31 geopolitical entities across six continents, our cross-level three-way interaction effect illustrates: As expected, managers in good barrels (high CEV/high CPI), mixed barrels (low CEV/high CPI or high CEV/low CPI), and bad barrels (low CEV/low CPI) display low, medium, and high magnitude of dishonesty, respectively. With high CEV, the intensity is the same across cultures. With low CEV, the intensity of dishonesty is the highest in high CPI entities (risk seeking of high probability)—the Enron Effect, but the lowest in low CPI entities (risk aversion of low probability). CPI has a strong impact on the magnitude of dishonesty, whereas CEV has a strong impact on the intensity of dishonesty. We demonstrate dishonesty in light of monetary values and two frames of social norm, revealing critical implications to the field of behavioral economics and business ethics.
Journal Article
Monetary Intelligence and Behavioral Economics Across 32 Cultures: Good Apples Enjoy Good Quality of Life in Good Barrels
2018
Monetary Intelligence theory asserts that individuals apply their money attitude to frame critical concerns in the context and strategically select certain options to achieve financial goals and ultimate happiness. This study explores the bright side of Monetary Intelligence and behavioral economics, frames money attitude in the context of pay and life satisfaction, and controls money at the macro-level (GDP per capita) and microlevel (Z income). We theorize: Managers with low love of money motive but high stewardship behavior will have high subjective well-being: pay satisfaction and quality of life. Data collected from 6586 managers in 32 cultures across six continents support our theory. Interestingly, GDP per capita is related to life satisfaction, but not to pay satisfaction. Individual income is related to both life and pay satisfaction. Neither GDP nor income is related to Happiness (money makes people happy). Our theoretical model across three GDP groups offers new discoveries: In high GDP (rich) entities, \"high income\" not only reduces aspirations—\"Rich, Motivator, and Power,\" but also promotes stewardship behavior—\"Budget, Give/Donate, and Contribute\" and appreciation of \"Achievement.\" After controlling income, we demonstrate the bright side of Monetary Intelligence: Low love of money motive but high stewardship behavior define Monetary Intelligence. \"Good apples enjoy good quality of life in good barrels.\" This notion adds another explanation to managers' low magnitude of dishonesty in entities with high Corruption Perceptions Index (CPI) (risk aversion for gains of high probability) (Tang et al. 2015. doi:10.1007/s10551-015-2942-4). In low GDP (poor) entities, high income is related to poor Budgeting skills and escalated Happiness. These managers experience equal satisfaction with pay and life. We add a new vocabulary to the conversation of monetary intelligence, income, GDP, happiness, subjective well-being, good and bad apples and barrels, corruption, and behavioral ethics.
Journal Article
Evaluacion nano-estructural de cristales de azucar como mecanismo de cualificacion de calidad
by
Andrés Rosero, Carlos
,
Zambrano Sánchez, Juan Camilo
,
Revelo André, Danilo
in
Automobiles
,
Citrus
2018
La evaluación de propiedades en los materiales a escala micrométrica o nanométrica ha permitido caracterizar y encontrar defectos propios que permiten medir la calidad de diferentes materiales orgánicos e inorgánicos. En este trabajo se planteó analizar la superficie de cristales de azúcar como una estructura organizada y proponer así un mecanismo de cualificación de la calidad intrínseca al proceso de su elaboración. Para esto se empleó técnicas no destructivas de microscopia óptica diferencial (DOM) y microscopia de fuerza atómica (AFM). Como resultado se encontró que la velocidad de cristalización afecta significativamente el tamaño y la estabilidad superficial del cristal de azúcar en una forma inversamente proporcional. Además, mediante el empleo de AFM se puede diferenciar y establecer mecanismos de cualificación de la calidad de los cristales analizados, tanto para definir un nivel de calidad en el proceso de cristalización, reconocer el nivel de impurezas minerales presentes y el nivel de irregularidades presentes.
Journal Article
The Escherichia coli bio¢lm-promoting protein Antigen 43 does not contribute to intestinal colonization
Escherichia coli is a versatile organism capable of causing a variety of intestinal and extraintestinal diseases, as well as existing as part of the commensal flora. A variety of factors permit specific attachment to host receptors including fimbrial adhesins and outer membrane proteins such as autotransporters. One of the better characterized autotransporters is Antigen 43 (Ag43), the major phase-variable surface protein of E. coli. Ag43 is associated with bacterial cell-cell aggregation and biofilm formation. Nevertheless, the precise biological significance and contribution to intestinal colonization remain to be elucidated. Here we investigated the contribution of Ag43 to E. coli adherence to intestinal epithelial cells and colonization of the mouse intestine. These investigations revealed that Ag43 increased in vitro adherence of E. coli to epithelial cells by promoting bacterial cell-cell aggregation but that Ag43 did not promote specific interactions with the mammalian cells. Furthermore, Ag43 did not contribute significantly to coloniza-tion of the mouse intestine and expression of Ag43 was lost a few days after colonization of the mouse was established. Unexpectedly, considering its similarity to other adhesins, our findings suggest that Ag43 does not act as a direct colonization factor by binding to mammalian cells.
Journal Article