2,075 research outputs found
Trends in alcohol use among Hawai‘i adolescents
It is important to review trends in youth alcohol use over time in order to effectively tailor prevention programs to address those trends. This article reviews data on alcohol use behaviors from the Centers for Disease Control and Prevention\u27s Youth Risk Behavior Survey in Hawai‘i from 1993 to 2007. Five alcohol use indicators were examined and stratified by grade level, from 9th grade through 12th grade. Significant drops in nearly all indicators are seen among 9th through 11th graders, but not among 12th graders. This suggests that Hawai‘i youth are responding well to anti-alcohol messaging as young teens, but a different approach may be needed to target older teens
A New Method to Estimate the Noise in Financial Correlation Matrices
Financial correlation matrices measure the unsystematic correlations between
stocks. Such information is important for risk management. The correlation
matrices are known to be ``noise dressed''. We develop a new and alternative
method to estimate this noise. To this end, we simulate certain time series and
random matrices which can model financial correlations. With our approach,
different correlation structures buried under this noise can be detected.
Moreover, we introduce a measure for the relation between noise and
correlations. Our method is based on a power mapping which efficiently
suppresses the noise. Neither further data processing nor additional input is
needed.Comment: 25 pages, 8 figure
Optimization of a Monobromobimane (MBB) Derivatization and RP-HPLC-FLD Detection Method for Sulfur Species Measurement in Human Serum after Sulfur Inhalation Treatment
(1) Background: Hydrogen sulfide (H2S) is a widely recognized gasotransmitter, with key roles in physiological and pathological processes. The accurate quantification of H2S and reactive sulfur species (RSS) may hold important implications for the diagnosis and prognosis of diseases. However, H2S species quantification in biological matrices is still a challenge. Among the sulfide detection methods, monobromobimane (MBB) derivatization coupled with reversed phase high-performance liquid chromatography (RP-HPLC) is one of the most reported. However, it is characterized by a complex preparation and time-consuming process, which may alter the actual H2S level; moreover, a quantitative validation has still not been described. (2) Methods: We developed and validated an improved analytical protocol for the MBB RP-HPLC method. MBB concentration, temperature and sample handling were optimized, and the calibration method was validated using leave-one-out cross-validation and tested in a clinical setting. (3) Results: The method shows high sensitivity and allows the quantification of H2S species, with a limit of detection of 0.5 mu M. Finally, it can be successfully applied in measurements of H2S levels in the serum of patients subjected to inhalation with vapors rich in H2S. (4) Conclusions: These data demonstrate that the proposed method is precise and reliable for measuring H2S species in biological matrices and can be used to provide key insights into the etiopathogenesis of several diseases and sulfur-based treatments. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Zero Mode and Symmetry Breaking on the Light Front
We study the zero mode and the spontaneous symmetry breaking on the light
front (LF). We use the discretized light-cone quantization (DLCQ) of
Maskawa-Yamawaki to treat the zero mode in a clean separation from all other
modes. It is then shown that the Nambu-Goldstone (NG) phase can be realized on
the trivial LF vacuum only when an explicit symmetry-breaking mass of the NG
boson is introduced. The NG-boson zero mode integrated over the LF
must exhibit singular behavior in the symmetric limit
, which implies that current conservation is violated at zero
mode, or equivalently the LF charge is not conserved even in the symmetric
limit. We demonstrate this peculiarity in a concrete model, the linear sigma
model, where the role of zero-mode constraint is clarified. We further compare
our result with the continuum theory. It is shown that in the continuum theory
it is difficult to remove the zero mode which is not a single mode with measure
zero but the accumulating point causing uncontrollable infrared singularity. A
possible way out within the continuum theory is also suggested based on the
`` theory''. We finally discuss another problem of the zero mode in the
continuum theory, i.e., no-go theorem of Nakanishi-Yamawaki on the
non-existence of LF quantum field theory within the framework of Wightman
axioms, which remains to be a challenge for DLCQ, `` theory'' or any other
framework of LF theory.Comment: 60 pages, the final section has been expanded. A few minor
corrections; version to be published in Phys. Rev.
RPA for Light-Front Hamiltonian Field Theory
A self-consistent random phase approximation (RPA) is proposed as an
effective Hamiltonian method in Light-Front Field Theory (LFFT). We apply the
general idea to the light-front massive Schwinger model to obtain a new bound
state equation and solve it numerically.Comment: A major revision in presentation, while the results essentially
unchanged. 2 figs. replaced, 1 fig. added, some parts of Sec. V moved to Sec.
IV, some wording changed, typos correcte
Low specificity of determine HIV1/2 RDT using whole blood in south west Tanzania
Objective: To evaluate the diagnostic performance of two rapid detection tests (RDTs) for HIV 1/2 in plasma and in whole blood samples.
Methods:
More than 15,000 study subjects above the age of two years participated in two rounds of a cohort study to determine the prevalence of HIV. HIV testing was performed using the Determine HIV 1/2 test (Abbott) in the first (2006/2007) and the HIV 1/2 STAT-PAK Dipstick Assay (Chembio) in the second round (2007/2008) of the survey. Positive results were classified into faint and strong bands depending on the visual appearance of the test strip and confirmed by ELISA and Western blot.
Results:
The sensitivity and specificity of the Determine RDT were 100% (95% confidence interval = 86.8 to 100%) and 96.8% (95.9 to 97.6%) in whole blood and 100% (99.7 to 100%) and 97.9% (97.6 to 98.1%) in plasma respectively. Specificity was highly dependent on the tested sample type: when using whole blood, 67.1% of positive results were false positive, as opposed to 17.4% in plasma. Test strips with only faint positive bands were more often false positive than strips showing strong bands and were more common in whole blood than in plasma. Evaluation of the STAT-PAK RDT in plasma during the second year resulted in a sensitivity of 99.7% (99.1 to 99.9%) and a specificity of 99.3% (99.1 to 99.4%) with 6.9% of the positive results being false.
Conclusions:
Our study shows that the Determine HIV 1/2 strip test with its high sensitivity is an excellent tool to screen for HIV infection, but that – at least in our setting – it can not be recommended as a confirmatory test in VCT campaigns where whole blood is used
X-linked hypophosphatemic rickets: An Italian experts' opinion survey
Background
X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases.
Objective
Due to the low prevalence of XLH, an experts\u2019 opinion survey was conducted across Italian centers to collect data on XLH and on its management.
Methods
A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy.
Results
Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5\u2009years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients.
Conclusions
XLH remains a severe condition with significant morbidities
X-linked hypophosphatemic rickets: An Italian experts' opinion survey
Background: X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases. Objective: Due to the low prevalence of XLH, an experts' opinion survey was conducted across Italian centers to collect data on XLH and on its management. Methods: A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy. Results: Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5 years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients. Conclusions: XLH remains a severe condition with significant morbidities
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