Nonlinear optical rectification (NOR) coefficients in symmetric double-graded quantum wells with different geometrical configurations under non-resonant laser field in the presence of electric and ...magnetic fields are theoretically investigated. The quantum states under the applied external fields are obtained under effective mass approximation and using diagonalization method. Our calculated results indicate that the above-mentioned external fields play a significant role in manipulating the resonant peak values and peak positions of nonlinear optical rectification coefficients of the quantum system dynamically. Considerable NOR coefficient can be achieved, not only by choosing appropriate laser dressing parameter as well as the electric and magnetic fields, but also by choosing appropriate well and barrier widths. Our results show great advantages in dynamically tuning NOR coefficient of symmetric double-graded quantum wells using multi-physic fields, paving the way for possible application for tunable infrared detector and signal processing based on symmetric double-graded quantum wells.
The rate of tuberculosis among foreign-born persons in the United States is approximately 10 times as high as that among U.S.-born persons. Diagnosis and treatment of tuberculosis before emigration ...can decrease the burden of tuberculosis in the United States. This study showed that from 1999 through 2005, about 30,000 cases of smear-negative tuberculosis and 33,000 cases of inactive tuberculosis were diagnosed by overseas medical screening of 3 million U.S.-bound immigrants and refugees.
This study showed that from 1999 through 2005, about 30,000 cases of smear-negative tuberculosis and 33,000 cases of inactive tuberculosis were diagnosed by overseas medical screening of 3 million U.S.-bound immigrants and refugees.
Tuberculosis is the second most common cause of death from infectious diseases in the world.
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During the period from 1990 through 2003, the incidence of tuberculosis increased globally.
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The World Health Organization (WHO) has reported that Asia and sub-Saharan Africa accounted for 84.1% of the estimated 8.8 million new cases of tuberculosis worldwide in 2005.
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Global migration has greatly affected the epidemiology of tuberculosis in developed countries. In 2007, foreign-born persons accounted for 57.8% of new cases of tuberculosis in the United States.
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In that year, the tuberculosis rate in the United States was 20.6 cases and 2.1 cases per . . .
While the number of reported tuberculosis (TB) cases in the United States has declined over the past two decades, TB morbidity among foreign-born persons has remained persistently elevated. A recent ...unexpected decline in reported TB cases among foreign-born persons beginning in 2007 provided an opportunity to examine contributing factors and inform future TB control strategies. We investigated the relative influence of three factors on the decline: 1) changes in the size of the foreign-born population through immigration and emigration, 2) changes in distribution of country of origin among foreign-born persons, and 3) changes in the TB case rates among foreign-born subpopulations. Using data from the U.S. National Tuberculosis Surveillance System and the American Community Survey, we examined TB case counts, TB case rates, and population estimates, stratified by years since U.S. entry and country of origin. Regression modeling was used to assess statistically significant changes in trend. Among foreign-born recent entrants (<3 years since U.S. entry), we found a 39.5% decline (-1,013 cases) beginning in 2007 (P<0.05 compared to 2000-2007) and ending in 2011 (P<0.05 compared to 2011-2014). Among recent entrants from Mexico, 80.7% of the decline was attributable to a decrease in population, while the declines among recent entrants from the Philippines, India, Vietnam, and China were almost exclusively (95.5%-100%) the result of decreases in TB case rates. Among foreign-born non-recent entrants (≥3 years since U.S. entry), we found an 8.9% decline (-443 cases) that resulted entirely (100%) from a decrease in the TB case rate. Both recent and non-recent entrants contributed to the decline in TB cases; factors contributing to the decline among recent entrants varied by country of origin. Strategies that impact both recent and non-recent entrants (e.g., investment in overseas TB control) as well as those that focus on non-recent entrants (e.g., expanded targeted testing of high-risk subgroups among non-recent entrants) will be necessary to achieve further declines in TB morbidity among foreign-born persons.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Among approximately 163.5 million foreign-born persons admitted to the United States annually, only 500,000 immigrants and refugees are required to undergo overseas tuberculosis (TB) screening. It is ...unclear what extent of the unscreened nonimmigrant visitors contributes to the burden of foreign-born TB in the United States.
We defined foreign-born persons within 1 year after arrival in the United States as "newly arrived", and utilized data from U.S. Department of Homeland Security, U.S. Centers for Disease Control and Prevention, and World Health Organization to estimate the incidence of TB among newly arrived foreign-born persons in the United States. During 2001 through 2008, 11,500 TB incident cases, including 291 multidrug-resistant TB incident cases, were estimated to occur among 20,989,738 person-years for the 1,479,542,654 newly arrived foreign-born persons in the United States. Of the 11,500 estimated TB incident cases, 41.6% (4,783) occurred among immigrants and refugees, 36.6% (4,211) among students/exchange visitors and temporary workers, 13.8% (1,589) among tourists and business travelers, and 7.3% (834) among Canadian and Mexican nonimmigrant visitors without an I-94 form (e.g., arrival-departure record). The top 3 newly arrived foreign-born populations with the largest estimated TB incident cases per 100,000 admissions were immigrants and refugees from high-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of ≥100 cases/100,000 population/year; 235.8 cases/100,000 admissions, 95% confidence interval CI, 228.3 to 243.3), students/exchange visitors and temporary workers from high-incidence countries (60.9 cases/100,000 admissions, 95% CI, 58.5 to 63.3), and immigrants and refugees from medium-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of 15-99 cases/100,000 population/year; 55.2 cases/100,000 admissions, 95% CI, 51.6 to 58.8).
Newly arrived nonimmigrant visitors contribute substantially to the burden of foreign-born TB in the United States. To achieve the goals of TB elimination, direct investment in global TB control and strategies to target nonimmigrant visitors should be considered.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In January 2005, tuberculosis (TB), including multidrug-resistant TB (MDR TB), was reported among Hmong refugees who were living in or had recently immigrated to the United States from a camp in ...Thailand. We investigated TB and drug resistance, enhanced TB screenings, and expanded treatment capacity in the camp. In February 2005, 272 patients with TB (24 MDR TB) remained in the camp. Among 17 MDR TB patients interviewed, 13 were found to be linked socially. Of 23 MDR TB isolates genotyped, 20 were similar according to 3 molecular typing methods. Before enhanced screening was implemented, 46 TB cases (6 MDR TB) were diagnosed in the United States among 9,455 resettled refugees. After enhanced screening had begun, only 4 TB cases (1 MDR TB), were found among 5,705 resettled refugees. An MDR TB outbreak among US-bound refugees led to importation of disease; enhanced pre-immigration TB screening and treatment decreased subsequent importation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background. Multivitamin use has been associated with lower risks for some birth defects. We evaluated whether multivitamin use modified birth defect risks associated with febrile illness, a common ...and possibly teratogenic exposure. Methods. From the population-based Atlanta Birth Defects Case-Control Study (1968-1980) we selected seven defects (neural tube defects, cleft lip and palate, cardiac outflow tract defects, ventricular septal defects, atrial septal defects, omphalocele, and limb deficiencies) because of their inverse relation with multivitamin supplement use documented in previous analyses. We defined four exposure categories from combinations of multivitamin use (periconceptional use compared with no use) and febrile illness (early pregnancy compared with no illness). The reference category was no multivitamin use and no illness. Results. Febrile illness with no multivitamin use was associated with generally increased risk for the seven defects and the combined group (odds ratio = 2.1, 1.7, 1.5, 1.9, 2.9, 4.4, 3.3, and 2.3, respectively). With multivitamin use, however, the risk estimates associated with febrile illness were generally lower (odds ratio = 0.6, 1.1, 0.0, 1.5, 0.0, 0.8, 0.0, and 0.8, respectively). Some of the associated 95% confidence intervals included one. Conclusions. The pattern of findings suggests that multivitamin use might decrease the risk associated with febrile illness.
Persons may seek asylum in the United States or at a U.S. port of entry. Principal asylees are those who are granted asylum status. Their spouse and unmarried children under 21 years of age may be ...granted asylum if accompanying, or following to join, the principal asylees. U.S.-bound follow-to-join asylees must undergo an overseas medical examination that includes tuberculosis (TB) screening. Culture-based overseas TB screening in U.S.-bound follow-to-join asylees has not been evaluated. We evaluated data from overseas TB screening in 19,088 arrivals of follow-to-join asylees during 2014-2019 and assessed data from their postarrival evaluation, which is recommended for those at risk for TB. Of 19,088 arrivals of follow-to-join asylees, 29 (152 cases/100,000 persons) met criteria for class B0 TB (recent completion of TB treatment overseas) and 340 (1,781 cases/100,000 persons) met criteria for class B1 pulmonary TB (chest radiograph/clinical symptoms suggestive of TB but negative sputum cultures overseas). Of 6,847 persons aged 2 to 14 years from countries with a WHO-estimated TB incidence of ≥20 cases/100,000 population/year, 408 (6.0%) were classified as class B2 latent TB infection (LTBI). Postarrival evaluations were completed in 44.8%, 51.5%, and 40.4% of persons with class B0 TB, class B1 TB, and class B2 LTBI, respectively. In conclusion, culture-based overseas TB screening in U.S.-bound follow-to-join asylees is effective in identifying those with TB (class B0 TB) or those at risk for TB (class B1 TB and class B2 LTBI). Completion of postarrival evaluation for newly arrived follow-to-join asylees was less frequent than that reported for immigrants and refugees.
Tuning electronic and optical properties of low-dimensional quantum systems in a flexible way is of particular importance in designing semiconductor-based devices. Semiconductor quantum rings (QRs) ...are nanoscopic structures that have become promising systems for physical and technological applications due to their unique electronic and optical properties. Here, we explore the fundamental electronic and optical properties of laterally-coupled QRs by taking into account the combined effects of applied magnetic and non-resonant terahertz intense laser fields. The laser-dressed electronic states are solved using the Floquet theory of periodically driven quantum systems in high-frequency limits within the framework of effective mass approximation. We demonstrate that increasing the laser field parameter leads to reduced tunnel splitting in the energy spectrum and more pronounced Aharonov-Bohm oscillations for the ground state energy, due to the attenuation of the tunnel coupling. Furthermore, depending on the position of the avoided crossings in Aharonov-Bohm oscillations of laterally-coupled quantum rings, the evolution of the avoided crossings with increasing the laser field parameter can be elucidated as the attenuated tunnel coupling or the competition between the attenuated tunnel coupling and the strengthening anisotropy of the laser-dressed QR potential well. The intensity of the intraband optical transition of laterally-coupled QRs can be effectively tuned and reaches a larger value by manipulating the laser parameter and magnetic field. Optical Aharonov-Bohm oscillations in laterally-coupled QRs are still exhibited by changing laser field parameters. Our findings offer a novel approach to manipulate the electronic and optical performances as well as the Aharonov-Bohm oscillations based on the laterally-coupled QRs by using an intense terahertz laser field.
Before 2007, immigrants and refugees bound for the United States were screened for tuberculosis (TB) by a smear-based algorithm that could not diagnose smear-negative/culture-positive TB. In 2007, ...the Centers for Disease Control and Prevention implemented a culture-based algorithm.
To evaluate the effect of the culture-based algorithm on preventing the importation of TB to the United States by immigrants and refugees from foreign countries.
Population-based, cross-sectional study.
Panel physician sites for overseas medical examination.
Immigrants and refugees with TB.
Comparison of the increase of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees by the culture-based algorithm with the decline of reported cases among foreign-born persons within 1 year after arrival in the United States from 2007 to 2012.
Of the 3 212 421 arrivals of immigrants and refugees from 2007 to 2012, a total of 1 650 961 (51.4%) were screened by the smear-based algorithm and 1 561 460 (48.6%) were screened by the culture-based algorithm. Among the 4032 TB cases diagnosed by the culture-based algorithm, 2195 (54.4%) were smear-negative/culture-positive. Before implementation (2002 to 2006), the annual number of reported cases among foreign-born persons within 1 year after arrival was relatively constant (range, 1424 to 1626 cases; mean, 1504 cases) but decreased from 1511 to 940 cases during implementation (2007 to 2012). During the same period, the annual number of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees bound for the United States by the culture-based algorithm increased from 4 to 629.
This analysis did not control for the decline in new arrivals of nonimmigrant visitors to the United States and the decrease of incidence of TB in their countries of origin.
Implementation of the culture-based algorithm may have substantially reduced the incidence of TB among newly arrived, foreign-born persons in the United States.
None.
In March 2021, Emergency Intake Sites (EIS) were created to address capacity shortfalls during a surge of Unaccompanied Children at the Mexico-United States land border. The COVID-19 Zone Plan (ZP) ...was developed to decrease COVID-19 transmission. COVID-19 cumulative percent (%) positivity was analyzed to evaluate the impact of the ZP, venue type and bed capacity across EIS from April 1–May 31, 2021. Results: Of 11 EIS sites analyzed, 54% implemented the recommended ZP. The overall % positivity was 2.47% (95% CI 2.39–2.55). The % positivity at EIS with the ZP, 1.83% (95% CI 1.71–1.95), was lower than that at EIS without the ZP, 2.83%, ( 95% CI 2.72–2.93), and showed a lower 7-day moving average of % positivity. Conclusion: Results showed a possible effect of the ZP on % positivity when controlling for venue type and bed capacity in a specific EIS group comparison, indicating that all three variables could have had effect on % positivity. They also showed that smaller intake facilities may be recommendable during public health emergencies.
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