Sinusoidal frequency modulated spectrum analysis

We will analyze the stationary frequency modulated (FM) process with the additive ambient noise Zt =Yi+t:t =Acos(wct+X(t)+<P)+t:t, fortE Z where X(t) = B sin(wo t + cp) (1.2) is the sinusoidalmodulatingprocess, A and B are constants, wc, wo E [0, 1r] are, respectively, the carrier· and the modulating frequencies and cp and <P are uniformly distributed random variables on ( -1r, 1r] independent of each other and of the noise process {t:t}tEZ· We will consider the noise process as being Gaussian and white for simplicity of the exposition. However, the results are similar for any stationary and ergodic process with continuous spectral density function. Here we will estimate the relevant parameters A, B, wc and w0 by an updating procedure based on HOC (higher order correlations) sequences in the fine tuning of parametric filters. \\7e will use two different parametric families of time invariant linear filters: the alpha and complex filters. Here we alleviate the assumption of Gaussianity for the signal and we prove its stationarity and ergodicity under appropriate conditions

Explicit bivariate rate functions for large deviations in AR(1) and MA(1) processes with Gaussian innovations

We investigate the large deviations properties for centered stationary AR(1) and MA(1) processes with independent Gaussian innovations, by giving the explicit bivariate rate functions for the sequence of two-dimensional random vectors [...]. Via the Contraction Principle, we provide the explicit rate functions for the sample mean and the sample second moment. In the AR(1) case, we also give the explicit rate function for the sequence of two-dimensional random vectors [...], but we obtain an analytic rate function that gives different values for the upper and lower bounds, depending on the evaluated set and its intersection with the respective set of exposed points. A careful analysis of the properties of a certain family of Toeplitz matrices is necessary. The large deviations properties of three particular sequences of one-dimensional random variables will follow after we show how to apply a weaker version of the Contraction Principle for our setting, providing new proofs for two already known results on the explicit deviation function for the sample second moment and Yule-Walker estimators. We exhibit the properties of the large deviations of the first-order empirical autocovariance, its explicit deviation function and this is also a new result

Fractionally integrated moving average stable processes with long-range dependence

Long memory processes driven by Lévy noise with finite second-order moments have been well studied in the literature. They form a very rich class of processes presenting an autocovariance function that decays like a power function. Here, we study a class of Lévy processes whose second-order moments are infinite, the so-called α-stable processes. Based on Samorodnitsky and Taqqu (1994), we construct an isometry that allows us to define stochastic integrals concerning the linear fractional stable motion using Riemann-Liouville fractional integrals. With this construction, an integration by parts formula follows naturally. We then present a family of stationary SαS processes with the property of long-range dependence, using a generalized measure to investigate its dependence structure. At the end, the law of large number’s result for a time’s sample of the process is shown as an application of the isometry and integration by parts formula

Parameter estimation in Manneville–Pomeau processes

In this paper, we study a class of stochastic processes [...], where[...] is obtained from the iterations of the transformation , invariant for an ergodic probability[...] on [...] and a certain constant by partial function [...]. We consider here the family of transformations[...] indexed by a parameter , known as the Manneville–Pomeau family of transformations. The autocorrelation function of the resulting process decays hyperbolically (or polynomially) and we obtain efficient methods to estimate the parameter[...] from a finite time series. As a consequence, we also estimate the rate of convergence of the autocorrelation decay of these processes. We compare different estimation methods based on the periodogram function, the smoothed periodogram function, the variance of the partial sum, and the wavelet theory. To obtain our results we analyzed the properties of the spectral density function and the associated Fourier series

Vivir con cáncer: la percepción de los pacientes oncológicos

Objective: to know the perception of living with cancer for oncological patients. Method: it is a qualitative, exploratory and descriptive study. It was developed in a radiotherapy center in a Teaching Hospital in south of Brazil, between October and November 2007. The participants were seven patients with cancer who came to the service for revision of up to six months after the end of the treatment. Results: the diagnosis brings changes and limitations to their lives, such as feelings of fear, sadness and anxiety. To overcome the adversities they count with the support of family, friends, work and religion. Conclusions: it is understood that this living is permeated by individual and subjective characteristics, occurring transformations in these people’s lives demanding that they find means to adapt to this new condition. Descriptors: Neoplasms; Survival; Oncologic nursing; Chronic disease; Life change events

Outcomes of the first 54 pediatric patients on long-term home parenteral nutrition from a single Brazilian center

Objectives: Data on multidisciplinary programs dedicated to home parenteral nutrition (HPN) in Latin America are limited. This study describes the results of the first multidisciplinary pediatric intestinal rehabilitation program for HPN at a public tertiary hospital in Brazil. Methods: We retrospectively reviewed patients aged 0–18 years with intestinal failure (IF) who required parenteral nutrition (PN) for >60 days between January/2014 and December/2020. Results: Fifty-four patients were discharged on HPN (15 achieved enteral autonomy, 34 continued on HPN at the end of the study, 1 underwent intestinal transplantation, and 4 died). The median (IQR) age at the study endpoint of patients who achieved enteral autonomy was 14.1 (9.7–19) versus 34.7 (20.4–53.9) months in those who did not achieve enteral autonomy. Overall prevalence of catheter-related thrombosis was 66.7% and catheterrelated bloodstream infection rate was 0.39/1000 catheter-days. Intestinal failure-associated liver disease (IFALD) was present in 24% of all patients; none of the patients who achieved enteral autonomy had IFALD. All patients showed significant improvement in anthropometric parameters during the HPN period. The sociodemographic characteristics of the patients’ family members were mothers less than 20 years old (7.5%), schooling time more than 10 years (55.5%), and household income between 1 and 3 times the minimum wage (64.8%). The 5-year survival rate for HPN is 90%, and 27.7% of patients achieve enteral autonomy. Conclusion: The treatment of pediatric patients with IF followed by a multidisciplinary pediatric intestinal rehabilitation program with HPN is feasible and safe in the Brazilian public health system

Frequency and Burden of Neurological Manifestations Upon Hospital Presentation in COVID-19 Patients: Findings From a Large Brazilian Cohort

BACKGROUND: Scientific data regarding the prevalence of COVID-19 neurological manifestations and prognosis in Latin America countries is still lacking. Therefore, the study aims to understand neurological manifestations of SARS-CoV 2 infection and outcomes in the Brazilian population. METHODS: This study is part of the Brazilian COVID-19 Registry, a multicentric cohort, including data from 37 hospitals. For the present analysis, patients were grouped according to the presence of reported symptoms (i.e., headache; anosmia and ageusia; syncope and dizziness) vs. clinically-diagnosed neurological manifestations (clinically-defined neurological syndrome: neurological signs or diagnoses captured by clinical evaluation) and matched with patients without neurological manifestations by age, sex, number of comorbidities, hospital of admission, and whether or not patients had underlying neurological disease. RESULTS: From 6,635 hospitalized patients with COVID-19, 30.8% presented reported neurological manifestations, 10.3% were diagnosed with a neurological syndrome and 60.1% did not show any neurological manifestations. In patients with reported symptoms, the most common ones were headache (20.7%), ageusia (11.1%) and anosmia (8.0%). In patients with neurological syndromes, acute encephalopathy was the most common diagnosis (9.7%). In the matched analysis, patients with neurological syndromes presented more cases of septic shock (17.0 vs. 13.0%, p = 0.045), intensive care unit admission (45.3 vs. 38.9%, p = 0.023), and mortality (38.7 vs. 32.6%, p = 0.026; and 39.2 vs. 30.3%, p \u3c 0.001) when compared to controls. CONCLUSION: COVID-19 in-hospital patients with clinically defined neurological syndromes presented a higher incidence of septic shock, ICU admission and death when compared to controls