Quadrature Control-Bounded ADCs

In this paper, the design flexibility of the control-bounded analog-to-digital converter principle is demonstrated by considering band-pass analog-to-digital conversion. We show how a low-pass control-bounded analog-to-digital converter can be translated into a band-pass version where the guaranteed stability, converter bandwidth, and signal-to-noise ratio are preserved while the center frequency for conversion can be positioned freely. The proposed converter is validated with behavioral simulations for a variety of filter orders, notch-filter frequencies, and oversampling ratios. Finally, robustness against component variations is demonstrated by Monte Carlo simulations.Comment: 5 pages, 6 figures, submitted to ISCAS 202

A Control-Bounded Quadrature Leapfrog ADC

In this paper, the design flexibility of the control-bounded analog-to-digital converter principle is demonstrated. A band-pass analog-to-digital converter is considered as an application and case study. We show how a low-pass control-bounded analog-to-digital converter can be translated into a band-pass version where the guaranteed stability, converter bandwidth, and signal-to-noise ratio are preserved while the center frequency for conversion can be positioned freely. The proposed converter is validated with behavioral simulations on several filter orders, center frequencies, and oversampling ratios. Additionally, we consider an op-amp circuit realization where the effects of first-order op-amp non-idealities are shown. Finally, robustness against component variations is demonstrated by Monte Carlo simulations.Comment: 13 pages and 16 figure

Dual-Specificity Phosphatase 1 (DUSP1) Has a Central Role in Redox Homeostasis and Inflammation in the Mouse Cochlea.

Stress-activated protein kinases (SAPK) are associated with sensorineural hearing loss (SNHL) of multiple etiologies. Their activity is tightly regulated by dual-specificity phosphatase 1 (DUSP1), whose loss of function leads to sustained SAPK activation. Dusp1 gene knockout in mice accelerates SNHL progression and triggers inflammation, redox imbalance and hair cell (HC) death. To better understand the link between inflammation and redox imbalance, we analyzed the cochlear transcriptome in Dusp1-/- mice. RNA sequencing analysis (GSE176114) indicated that Dusp1-/- cochleae can be defined by a distinct profile of key cellular expression programs, including genes of the inflammatory response and glutathione (GSH) metabolism. To dissociate the two components, we treated Dusp1-/- mice with N-acetylcysteine, and hearing was followed-up longitudinally by auditory brainstem response recordings. A combination of immunofluorescence, Western blotting, enzymatic activity, GSH levels measurements and RT-qPCR techniques were used. N-acetylcysteine treatment delayed the onset of SNHL and mitigated cochlear damage, with fewer TUNEL+ HC and lower numbers of spiral ganglion neurons with p-H2AX foci. N-acetylcysteine not only improved the redox balance in Dusp1-/- mice but also inhibited cytokine production and reduced macrophage recruitment. Our data point to a critical role for DUSP1 in controlling the cross-talk between oxidative stress and inflammation

A Comparative Study of Age-Related Hearing Loss in Wild Type and Insulin-Like Growth Factor I Deficient Mice

Insulin-like growth factor-I (IGF-I) belongs to the family of insulin-related peptides that fulfils a key role during the late development of the nervous system. Human IGF1 mutations cause profound deafness, poor growth and mental retardation. Accordingly, Igf1−/− null mice are dwarfs that have low survival rates, cochlear alterations and severe sensorineural deafness. Presbycusis (age-related hearing loss) is a common disorder associated with aging that causes social and cognitive problems. Aging is also associated with a decrease in circulating IGF-I levels and this reduction has been related to cognitive and brain alterations, although there is no information as yet regarding the relationship between presbycusis and IGF-I biodisponibility. Here we present a longitudinal study of wild type Igf1+/+ and null Igf1−/− mice from 2 to 12 months of age comparing the temporal progression of several parameters: hearing, brain morphology, cochlear cytoarchitecture, insulin-related factors and IGF gene expression and IGF-I serum levels. Complementary invasive and non-invasive techniques were used, including auditory brainstem-evoked response (ABR) recordings and in vivo MRI brain imaging. Igf1−/− null mice presented profound deafness at all the ages studied, without any obvious worsening of hearing parameters with aging. Igf1+/+ wild type mice suffered significant age-related hearing loss, their auditory thresholds and peak I latencies augmenting as they aged, in parallel with a decrease in the circulating levels of IGF-I. Accordingly, there was an age-related spiral ganglion degeneration in wild type mice that was not evident in the Igf1 null mice. However, the Igf1−/− null mice in turn developed a prematurely aged stria vascularis reminiscent of the diabetic strial phenotype. Our data indicate that IGF-I is required for the correct development and maintenance of hearing, supporting the idea that IGF-I-based therapies could contribute to prevent or ameliorate age-related hearing loss

New Approach to Designing Functional Materials for Stealth Technology: Radar Experiment with Bilayer Absorbers and Optimization of the Reflection Loss

Microwave power absorption by a two-layer system deposited on a metallic surface is studied in the experimental setup emulating the response to a radar signal. Layers containing hexaferrite and iron powder in a dried paint of thickness under 1 mm are used. The data is analyzed within a theoretical model derived for a bilayer system from the transmission line theory. A good agreement between experimental and theoretical results is found. The advantage of using a bilayer system over a single-layer system is demonstrated. How the maximum microwave absorption (minimum reflection) can be achieved through the optimization of the filling factors and thicknesses of the two layers is shown

Sexual behavior, use of contraceptive methods and pregnancy in young people from a population affiliated in a health insurer company in Colombia 2018

Describe the average age of sexual life onset from young people and adolescents, the prevalence of contraceptive methods and explore determinants of pregnancy. A retrospective cohort (2014-2018) was followed by a health insurer of the subsidized regime in Colombia. The study sample consisted of 35,214 young people aged 10-24 years living in 21 municipalities of the Colombian Caribbean region. For the social determinants of pregnancy, a multivariate probit model was estimated using as explanatory variables, housing area, education, family functionality and sexual behavior. 10.3% of women and 14.1% of men had their first sexual encounter before age 14 and 43.5% of women and 37.4% of men began their sex life after age 17. From the young people who claimed to have started their sexual life, 70.9% of the men made use of the condom as a contraceptive method, while the women divided on average 27.2% for the pills and / or injections followed by 16 , 1% in the use of the subdermal implant. As determinants of pregnancy in young people under 20, it was found that variables such as suspending school years [Yes (β = 0.6, p = 0.006)], being planned with hormonal method [Yes (β = 0.5, p = 0.000)] or start sexual life [Between 10 to 14 years (β = 0.14, p = 0.000)], increase the likelihood of young women becoming pregnant at some time in their life. These results also showed that the schooling of the young [University (β = -0.4, p = 0.038)] and always use condoms in sexual intercourse [Yes (β = -0.5, p = 0.042)] help prevent the pregnancy event from occurring. The age of sexual onset establishes a basis on which decision makers should intervene for promote a safe sex life, from use of anticonceptives in young people and thus avoiding unplanned pregnancy

Perception, prevalence and factors associated to school bullying in young people from a population affiliated in a colombian health subsidized insurance company in 2018.

Describe the perception from young people about bullying, the prevalence of this event and explore the factors associated with being a victim. A retrospective cohort (2014-2018) was followed by a health insurer company of the subsidized regime in Colombia. The study sample consisted of 35,214 young people aged 10-24 years living in 21 municipalities of the Colombian Caribbean region. Means and standard deviation were expressed for continuous variables and frequencies for categorical variables. For the associated factors, a logistic model was estimated using as explanatory variables, sex, housing area, age range, family functionality, disability of the young person, disability of a family member and variables of psychological perception. 63.6% of young people answered that they have knowledge about what school bullying is, noting that as the schooling of the young person increases, the higher the proportion of positive response. The physical or verbal school bullying rate was 94 young people per 1,000. It was found that factors such as the youth feeling useless and guilty (OR = 3.14, p = 0.000), attending psychological counseling (OR = 1.78, p = 0.000), repeating years (OR = 1.49, p = 0.000), that the young person has a disability (OR = 1.33, p = 0.004), or a family member has a disability (OR = 1.27, p = 0.000), is associated with being a victim of bullying. Likewise, it was found that belonging to a highly functional family environment (OR = 0.57, p = 0.000) is a protective factor. School bullying is an event that needs attention and requires supervision of all those around young people, in order to avoid changes in behavior or suicide. Therefore, health systems must offer comprehensive care to prevent mental health risks related to bullying given their relationship with the presence of disability of the young person or a relativ