94 research outputs found
Quantum Dissipation in a Neutrino System Propagating in Vacuum and in Matter
Considering the neutrino state like an open quantum system, we analyze its
propagation in vacuum or in matter. After defining what can be called
decoherence and relaxation effects, we show that in general the probabilities
in vacuum and in constant matter can be written in a similar way, which is not
an obvious result in this approach. From this result, we analyze the situation
where neutrinos evolution satisfies the adiabatic limit and use this formalim
to study solar neutrinos. We show that the decoherence effect may not be
bounded by the solar neutrino data and review some results in the literature.
We discuss the current results where solar neutrinos were used to put bounds on
decoherence effects through a model-dependent approach. We conclude explaining
how and why this models are not general and we reinterpret these constraints.Comment: new version: title was changend and was added a table. To appear at
Nucl. Physic.
On the Effects of Quantum Decoherence in a Future Supernova Neutrino Detection
Quantum decoherence effects in neutrinos, described by the open quantum
systems formalism, serve as a gateway to explore potential new physics,
including quantum gravity. Previous research extensively investigated these
effects across various neutrino sources, imposing stringent constraints on the
spontaneous loss of coherence. In this study, we demonstrate that even within
the Supernovae environment, where neutrinos are released as incoherent states,
quantum decoherence could influence the flavor equipartition of mixing.
Additionally, we examine the potential energy dependence of quantum decoherence
parameters () with different power laws (). Our findings indicate that future-generation detectors (DUNE,
Hyper-K, and JUNO) can significantly constrain quantum decoherence effects
under different scenarios. For a Supernova located 10 kpc away from Earth, DUNE
could potentially establish bounds of eV in the normal mass hierarchy (NH) scenario, while Hyper-K could
impose a limit of eV for the
inverted mass hierarchy (IH) scenario with - assuming no energy exchange
between the neutrino subsystem and non-standard environment ().
These limits become even more restrictive for a closer Supernova. When we relax
the assumption of energy exchange (), for a 10 kpc SN, DUNE can
establish a limit of eV for NH,
while Hyper-K could constrain eV for IH
() with , representing the most stringent bounds reported to
date. Furthermore, we examine the impact of neutrino loss during propagation
for future Supernova detection
An Intelligent Multicriteria Model for Diagnosing Dementia in People Infected with Human Immunodeficiency Virus
Hybrid models to detect dementia based on Machine Learning can provide accurate
diagnoses in individuals with neurological disorders and cognitive complications caused by Human
Immunodeficiency Virus (HIV) infection. This study proposes a hybrid approach, using Machine
Learning algorithms associated with the multicriteria method of Verbal Decision Analysis (VDA).
Dementia, which affects many HIV-infected individuals, refers to neurodevelopmental and mental
disorders. Some manuals standardize the information used in the correct detection of neurological
disorders with cognitive complications. Among the most common manuals used are the DSM-5
(Diagnostic and Statistical Manual of Mental Disorders, 5th edition) of the American Psychiatric
Association and the International Classification of Diseases, 10th edition (ICD-10)—both published
byWorld Health Organization (WHO). The model is designed to explore the predictive of specific
data. Furthermore, a well-defined database data set improves and optimizes the diagnostic models
sought in the research.info:eu-repo/semantics/publishedVersio
Hybrid model for early identification post-Covid-19 sequelae
Artificial Intelligence techniques based on Machine Learning algorithms, Neural Networks and Naïve Bayes can optimise the diagnostic process of the SARS-CoV-2 or Covid-19. The most significant help of these techniques is analysing data recorded by health professionals when treating patients with this disease. Health professionals' more specific focus is due to the reduction in the number of observable signs and symptoms, ranging from an acute respiratory condition to severe pneumonia, showing an efficient form of attribute engineering. It is important to note that the clinical diagnosis can vary from asymptomatic to extremely harsh conditions. About 80% of patients with Covid-19 may be asymptomatic or have few symptoms. Approximately 20% of the detected cases require hospital care because they have difficulty breathing, of which about 5% may require ventilatory support in the Intensive Care Unit. Also, the present study proposes a hybrid approach model, structured in the composition of Artificial Intelligence techniques, using Machine Learning algorithms, associated with multicriteria methods of decision support based on the Verbal Decision Analysis methodology, aiming at the discovery of knowledge, as well as exploring the predictive power of specific data in this study, to optimise the diagnostic models of Covid-19. Thus, the model will provide greater accuracy to the diagnosis sought through clinical observation.info:eu-repo/semantics/publishedVersio
Host-defense peptides AC12, DK16 and RC11 with immunomodulatory activity isolated from Hypsiboas raniceps skin secretion
Inflammation is a natural defense mechanism of the immune system; however, when unregulated, it can lead to chronic illness. Glucocorticoids are the most commonly used agents to effectively treat inflammatory conditions, including autoimmune diseases, however these substances can trigger a number of side effects. Thus, viable alternatives to the use of these drugs would be advantageous. In this study, we have analyzed the anti-inflammatory profile of three synthetic peptides first identified in skin secretion of the tree frog Hypsiboas raniceps. Structural characterization was performed using NMR spectroscopy and Mass Spectrometry, and the peptides were tested in vitro in RAW 264.7 cells and in vivo in Balb/c mice for their functional properties. The samples did not show a significant antimicrobial profile. NMR spectroscopy indicated that AC12 (ACFLTRLGTYVC) has a disulfide bond between C2 and C11 and a β-sheet-turn-β-sheet conformation in aqueous solution. This peptide showed no cytotoxic effect in mammalian cells and it was the most effective in reducing anti-inflammatory markers, such as NO, TNF-α and IL-12. Peptide DK16 (DKERPICSNTFRGRKC) demonstrated anti-inflammatory properties in vitro, while RC11 (RCFRRRGKLTC) significantly altered the cell viability in RAW 264.7 but was shown to be safe in Balb/c erythrocytes. Our results indicate that, of the three peptides studied, AC12 is the most efficient in reducing anti-inflammatory markers, and it could be a potential agent for the treatment of inflammatory diseases.publishe
Effect of essential oil of Alpinia zerumbet on cardiovascular and autonomic function in rats with isoproterenol induced acute myocardial infarction
Abstract Alpinia zerumbet is a plant popularly used to treat hypertension and anxiety. Studies with Alpinia zerumbet demonstrate antihypertensive and vasodilator effects, among others. The objective of this study was to analyze the effect of essential oil of Alpinia zerumbet (EOAz) on cardiovascular and autonomic function in rats with isoproterenol-induced myocardial infarction. Male Wistar rats (n=32) were equally allocated into four groups: Control, ISO (150mg/kg, subcutaneous), EOAz (100mg/kg by gavage), ISO+EOAz. The rats were evaluated for cardiovascular and, autonomic parameters, electrocardiogram, and infarct size. EOAz was not able to reduce the electrocardiographic variations induced by ISO. Heart rate variability showed a decrease in sympathetic modulation on the heart in the groups treated with EOAz. The cardiopulmonary reflex induced by serotonin invoked a superior blood pressure variation at the 2 µg/kg dose in the EOAz treated groups, while the heart rate variation was significantly higher at the 16 µg/kg dose, when compared to other doses, in all groups, except EOAz+ISO. The sympathetic vagal index was higher in ISO group than in control. EOAz did not reduce the infarct size. We conclude that pretreatment with EOAz does not reverse the hemodynamic and electrocardiographic damage caused by isoproterenol but does reduce sympathetic modulation
Para além de um prefácio: ditadura e democracia no diálogo entre Antonio Candido e Sérgio Buarque de Holanda
Solar neutrinos: global analysis with day and night spectra from SNO
We perform global analysis of the solar neutrino data including the day and
night spectra of events at SNO. In the context of two active neutrino mixing,
the best fit of the data is provided by the LMA MSW solution with Delta m^2 =
6.15 10^{-5} eV^2, tan^2\theta = 0.41, f_B = 1.05, where f_B is the boron
neutrino flux in units of the corresponding flux in the Standard Solar Model
(SSM). At 3 sigma level we find the following upper bounds: tan^2\theta < 0.84
and Delta m^2 < 3.6 10^{-4} eV^2. From 1 sigma-interval we expect the day-night
asymmetries of the charged current and electron scattering events to be:
A_{DN}^{CC} = 3.9 +3.6-2.9 and A_{DN}^{ES} = 2.1 +2.1-1.4. The only other
solution which appears at 3 sigma-level is the VAC solution with Delta m^2 =
4.5 10^{-10} eV^2, tan^2\theta = 2.1 and f_B=0.75. The best fit point in the
LOW region, with Delta m^2 = 0.93 10^{-7} eV^2 and tan^2\theta = 0.64, is
accepted at 99.95% (3.5 sigma) C.L. . The least chi^2 point from the SMA
solution region, with Delta m^2 = 4.6 10^{-6} eV^2 and tan^2\theta = 5 10^{-4},
could be accepted at 5.5 sigma-level only. In the three neutrino context the
influence of theta_{13} is studied. We find that with increase of theta_{13}
the LMA best fit point shifts to larger Delta m^2, mixing angle is practically
unchanged, and the quality of the fit becomes worse. The fits of LOW and SMA
slightly improve. Predictions for KamLAND experiment (total rates, spectrum
distortion) have been calculated.Comment: Typos corrected, reference adde
Dilatação dos confins: caminhos, vilas e cidades na formação da Capitania de São Paulo (1532-1822)
Este ensaio analisa a formação da rede urbana das capitanias de São Vicente e Santo Amaro, depois unidas na Capitania de São Paulo. Discute o processo de apropriação do sertão, a pulsação e dilatação dos confins ao sabor dos deslocamentos humanos e de interesses polÃticos. Interpreta o papel de capelas, freguesias, vilas e cidades no controle e produção de territórios metropolitanos em solos ultramarinos.This essay analyzes the development of urban networks in the Captaincies of São Vicente and Santo Amaro, later merged into the Captaincy of São Paulo. It discusses the process of appropriation of the sertão (backcountry), the commotion and expansion beyond the confines to the tune of population movements and political interests. The paper also interprets the role of chapels, parishes, villages and towns in initiatives to create and control metropolitan areas on overseas soil
- …