Search

This study reports on the impact of international visiting faculty's teaching experiences in the United States on their personal, professional, and intercultural development. It is based on the principles of qualitative research and can be described as a case study. Data collection involved a questionnaire, a written narrative, and a semi-structured interview with each of a number of teachers. Participants included a group of 22 visiting faculty. Three main categories, each of which can be subdivided into benefits and challenges, emerged from the analysis: intercultural matters, professional matters, and personal matters. A wide range of benefits was identified, suggesting that the participants adapted to new life styles, became more mature, obtained a deeper understanding of themselves, reaffirmed their own educational values and philosophies, raised cultural awareness, became more flexible, and developed attitudes that involved tolerance and respect. Conversely, visiting faculty reported that they faced challenges related to language barriers, interaction with native speakers, classroom management, lack of support from school administrators, and separation from family.

The Plomosas deposit is the product of a sequence of overlapping events of Pb–Zn, Ag, and Au low sulfidation mineralization that occurred in Mexico’s southwestern Sierra Madre Occidental (SMO). Field observations, detailed petrography, and U–Pb age dating of the entire stratigraphic sequence were used to characterize the magmatic evolution of the district and to obtain new insights into the evolution of the SMO. The stratigraphy at Plomosas is distinct from other areas to the north as it lacks Jurassic marine units, Cretaceous continental volcanic successions as well as Cretaceous and Palaeocene batholiths. The local basement is composed of undeformed Late Jurassic volcaniclastic units and coeval felsic intrusions. Early to late Oligocene silicic ignimbrites, intermediate lava flows, and occasional basaltic flows unconformably overlie the Jurassic basement. Several Oligocene intermediate to felsic porphyry bodies and rhyolitic domes crosscut the stratigraphy. The upper volcanic sequence is separated into two packages by an angular unconformity. Mineralization produced an early Pb–Zn-mineralized hydrothermal fault breccia, followed by Cu–Ag veins and late Au veins. The Pb–Zn mineralized breccia is hosted by ~30 Ma Oligocene volcanic units that form the basal sequence. The Cu–Ag and Au-rich veins overlap and crosscut the early hydrothermal features and cut the late Oligocene volcanic cover that unconformably overlie the basal sequence. Our results highlight the importance of episodes of Oligocene magmatism to the genesis of mineralization in the southwestern SMO specifically through a genetic link between Pb–Zn veins and intermediate Oligocene intrusive bodies, and of Ag and Au veins with late Oligocene volcanism. [ABSTRACT FROM AUTHOR]

Bouvardia ternifolia (Cav.) Schltdl. is a shrub that belongs to the Rubiaceae family and is distributed throughout México; it has been used for its antioxidant, neuroprotective, and anti-inflammatory properties. This work aimed to evaluate the protective effects of B. ternifolia root extracts on the blood-brain barrier and the positive regulation of cytokines IL-1β, IL-6, and TNF-α, and the characterization of compounds present in the dichloromethane (BtD) and hexane (BtH) extracts. Male ICR mice were orally administered with B. ternifolia extracts for 5 days before a single injection of LPS. Administration of BtH and BtD significantly decreased Evans blue leakage into brain tissue by 70% and 68%, respectively. Meloxicam (MX) decreased the concentration of IL-1β by 39.6%; BtM by 53.9%; BtAq by 48.4%; BtD by 31.9%, and BtH by 37.7%. BtH was the only treatment that significantly decreased the concentration of IL-6 by 32.2%. The concentration of TNF-α declined with each of the treatments. The chemical composition of BtD and BtH was characterized by GC–MS, and the cyclic hexapeptide was identified by 13C, 1H NMR, and two-dimension techniques. In the BtD extract, seven compounds were found and in BtH 13 compounds were found. The methanolic (BtM) and aqueous (BtAq) extracts were not subjected to chemical analysis, because they did not show a significant difference in the BBB protection activity. Therefore, the results suggested that the extracts BtD and BtH protect the blood-brain barrier, maintaining stable its selective permeability, thereby preventing LPS from entering the brain tissue. Simultaneously, they modulate the production of IL-1β, IL-6, and TNF-α. It is important to note that this research only evaluated the complete extracts. [ABSTRACT FROM AUTHOR]

Alopecia areata (AA) represents an underrecognized burden in Latin America (LA), severely impacting quality of life (QoL). This impact is exacerbated by limited access to specialized dermatologic care and therapies for AA within and among nations. Many of the unmet needs for AA globally also exist in LA. The region has geographic, ethnic, cultural, and economic conditions. With new AA medicines targeting immunologic pathways on the horizon, LA must prepare regarding regulatory issues, reimbursement, awareness, and education to give adequate and timely treatment for patients with AA. To address these issues, the Americas Health Foundation convened a panel of six dermatologists from Argentina, Brazil, Colombia, and Mexico who are experts in AA and its comorbidities for a 3-day virtual meeting to discuss AA diagnosis and treatment in LA and create a manuscript offering recommendations to address discussed barriers. This publication examines unmet AA needs in LA, treatment, and innovative therapies and recommends improving AA care. Access constraints to conventional and novel medicines hinder appropriate treatments for patients. Therapy initiation delays can affect QoL, mental health, and disease progression. People with AA face stigmas, discrimination, and misconceptions owing to a lack of disease awareness. With promising new treatments for AA on the horizon, all stakeholders must coordinate efforts to enhance LA's AA management landscape and improve patient outcomes. [ABSTRACT FROM AUTHOR]

Sarcopenia has an important impact in elderly. Recently the European Working Group on Sarcopenia in Older People (EWGSOP) defined sarcopenia as the loss of muscle mass plus low muscle strength or low physical performance. Lack of clinical sounding outcomes (ie external validity), is one of the flaws of this algorithm. The aim of our study was to determine the association of sarcopenia and mortality in a group of Mexican elderly. A total of 345 elderly were recruited in Mexico City, and followed up for three years. The EWGSOP algorithm was integrated by: gait speed, grip strength and calf circumference. Other covariates were assessed in order to test the independent association of sarcopenia with mortality. Of the 345 subjects, 53.3% were women; with a mean age of 78.5 (SD 7) years. During the three year follow-up a total of 43 (12.4%) subjects died. Age, cognition, ADL, IADL, health self-perception, ischemic heart disease and sarcopenia were associated in the bivariate analysis with survival. Negative predictive value for sarcopenia regarding mortality was of 90%. Kaplan-Meier curves along with their respective log-rank test were significant for sarcopenia. The components of the final Cox-regression multivariate model were age, ischemic heart disease, ADL and sarcopenia. Adjusted HR for age was 3.24 (CI 95% 1.55-6.78 p 0.002), IHD 5.07 (CI 95% 1.89-13.59 p 0.001), health self-perception 5.07 (CI 95% 1.9-13.6 p 0.001), ADL 0.75 (CI 95% 0.56-0.99 p 0.048) and sarcopenia 2.39 (CI 95% 1.05-5.43 p 0.037). [ABSTRACT FROM AUTHOR]

Abstract: Sarcopenia is an increasingly recognized problem in the elderly. Recently an algorithm to detect this condition was developed. The aim of our study was to determine the prevalence of sarcopenia in a group of elderly in Mexico City, using the European Wording Group on Sarcopenia in Older People (EWGSOP) algorithm. A cross-sectional assessment of community dwelling elderly was performed in a sample of 345 subjects, who were 70 years or older, during the year of 2008. The data was gathered by a group of standardized interviewers. In order to determine sarcopenia, muscle mass, muscle strength and physical performance were obtained from database. Muscle mass was measured by means of calf circumference, muscle strength by grip strength and physical performance by gait speed. Cut-points suggested in the EWGSOP algorithm of sarcopenia detection (ASD) were used. A total number of 116 (33.6%) subjects were detected as sarcopenic, 75 (48.5%) women and 41 (27.4%) men; with a greater prevalence in 80-year or older subjects (50.4%). Sarcopenic obesity was found in five subjects (1.4%), moderate sarcopenia in 21 subjects (6%) and severe sarcopenia in 94 subjects (27.2%). The ASD of the EWGSOP is a useful tool for detecting sarcopenia prevalence; the frequency in our population was similar to other reports using other methodology. [Copyright &y& Elsevier]

• We present new microthermometric and isotopic characterization of the Eocene-Oligocene Ag–Au mineralizing events. • We present new noble gases characterization of the Eocene-Oligocene Ag–Au mineralizing events. • We propose an integrate metallogenic model for the Telescoped Ag-Eocene and Au-Oligocene San Dimas district. The San Dimas district is a world-class Ag/Au deposit, developed as a telescoped Eocene-Oligocene Ag/Au mineralization located in the Sierra Madre Occidental (SMO) of western Mexico. San Dimas exhibits multiple mineralization events during different magmatic and tectonic episodes from Late Cretaceous to early Oligocene. The well-preserved magmatic-hydrothermal system provides an excellent opportunity to determine the source of silver and gold, the evolution of the hydrothermal fluids, and the controls on the mineralization precipitation. Mineralogical, fluid inclusions (FI), stable and noble gases isotope analyses suggest that the San Dimas deposit consist of two different mineralization styles: 1) Ag-dominant epithermal Eocene veins that occurred at temperatures up to ~350 °C developed at ca. 2–3 km depth, associated to the final stages of intrusion of the Piaxtla batholith, with FI dominated by a crustal component, and 2) epithermal low sulfidation Au-dominant Oligocene veins which were developed at 250 °C, at shallower depths (<1 km), associated to the feeding fractures of rhyolitic domes developed at the end of the main ignimbrite flare up of the SMO, with FI showing crustal fluids variably mixed with a magmatic component. Our results highlight the importance of a multidisciplinary approach, such as field observations, geochronological and geochemical studies, to better understand the complexity of the hydrothermal magmatic processes involved in the formation of many Mexican ore deposits and their proper classification. [ABSTRACT FROM AUTHOR]

• We identify three styles of mineralization in the telescoped Au/Ag San Dimas district. • We recognized for the first time a Late Cretaceous Cu-Porphyry episode. • An Eocene Ag-rich hydrothermal event occurred at the end of the Piaxla batholith emplacement. • An early Oligocene Au-rich low sulfidation event is related to rhyolite dome emplacement. • Progressive exhumation allows spatial superposition of pulses occurring at different depths. The San Dimas district is a historical world class Ag/Au epithermal deposit located in the Sierra Madre Occidental (SMO) of western Mexico. San Dimas has been classified as a classic low to intermediate sulfidation Ag/Au epithermal deposit (quartz + adularia + sericite type) developed during a single hydrothermal pulse of ~10 Ma, associated to the emplacement of intermediate intrusive bodies of Eocene K-Ar ages. However, this metallogenetic model includes several ambiguities, such as K-Ar cooling ages incompatible with the local and regional magmatic pulses, as well as wide differences in Ag-Au ratios between individual veins, which were also emplaced in two different structural systems. Based on a detailed study of mineralized veins, including new petrographic observations, new geochronological data (zircon U-Pb, adularia 40Ar/39Ar, and titanite fission track ages, FT), zircon trace-element composition, and geochemistry of gold and silver minerals, we demonstrate that San Dimas exhibits multiple mineralization events developed during different magmatic and tectonic episodes from Late Cretaceous to early Oligocene. The earliest episode is represented by Late Cretaceous copper – gold porphyry mineralization associated with fertile and oxidized magmas during the development of the Laramide arc. The second, most abundant ore mineralization is represented by a Ag-dominant vein system (adularia + rhodochrosite type), which developed into east-west striking fractures. New 40Ar/39Ar ages on adularia as well as new titanite FT ages for this mineralization event, together with one published 40Ar/39Ar age indicate the formation of Ag rich veins at ~41–40 Ma, shortly after the final emplacement of the Piaxtla batholith (~45 Ma), which formed from multiple fertile and oxidized magma intrusions in an extensional environment. The third mineralization episode is represented by Au-dominant epithermal veins (quartz sericite type), which were emplaced at ~31 Ma into north-south to NNE-SSE striking fractures. At regional scale these fractures also host rhyolitic domes associated with the first silicic ignimbrite flare up of the SMO in an extensional setting. The formation of the San Dimas district with its exceptionally rich Ag-Au mineralization is interpreted to be related to an extension-related late Eocene-early Oligocene regional uplift that allowed the overprinting of originally deeper Ag veins by a shallower Au mineralizing event. [ABSTRACT FROM AUTHOR]