On the Sum of Fisher-Snedecor F Variates and its Application to Maximal-Ratio Combining

Capitalizing on the recently proposed Fisher-Snedecor F composite fading model, in this letter, we investigate the sum of independent but not identically distributed (i.n.i.d.) Fisher-Snedecor F variates. First, a novel closed-form expression is derived for the moment generating function of the instantaneous signal-to-noise ratio. Based on this, the corresponding probability density function and cumulative distribution function of the sum of i.n.i.d. Fisher- Snedecor F variates are derived, which are subsequently employed in the analysis of multiple branch maximal-ratio combining (MRC). Specifically, we investigate the impact of multipath and shadowed fading on the outage probability and outage capacity of MRC based receivers. In addition, we derive exact closed-form expressions for the average bit error rate of coherent binary modulation schemes followed by an asymptotic analysis which provides further insights into the effect of the system parameters on the overall performance. Importantly, it is shown that the effect of multipath fading on the system performance is more pronounced than that of shadowing.Comment: 5 pages, 3 figure

The effectivity of science manipulative based smart class virtual laboratory to improve science process skill

This study aims to determine the effectiveness of using a smart class virtual laboratory based on Science Manipulative Learning with the dimensions of the Pancasila student profile through PhET Simulation and OLABS on the science process skills of PGSD students. This research is an experimental study with a research design of a nonequivalent control group design and sampling technique by purposive sampling. The sample in the study was PGSD students in semester 2 of the SD Science Laboratory course in Group J and M totaling 50 people. Data collection techniques used tests and non-tests. Tests are used to measure science process skills through Pre-test and Post-test. Non-test is used to observe student activities during learning using a smart class virtual laboratory based on science manipulative learning through PhET Simulation with observation sheets and questionnaires. Data analysis techniques use the Normality Test of gain (Normalized-Gain), Homogeneity Test, Test the effect between variables using a Paired Sample T-test, and the effect between variables using an Independent T-test. The results and analysis can conclude that the application of Smart Class Virtual Laboratory Based on Science Manipulative Learning Dimensioned Pancasila Student Profile Through PhET Simulation and OLABS effectively improves science process skills. This is evidenced by the pretest and posttest N-Gain test values, which obtained a score of 0.64 with a moderate increase in the category

O significado clínico das alucinações nas doenças neurodegenerativas do Sistema Nervoso Central e particularmente no Parkinson

Por definição, as verdadeiras alucinações são concebidas como indistinguíveis das percepções reais, excetuando o facto de que não há um estímulo. Para estes propósitos, uma percepção real ocorre no espaço objetivo externo, tem um caráter de objetividade, é recebida pela pessoa que a experiencia com uma atitude de passividade, e os elementos sensoriais são marcantes, frescos e constantes, sendo inalteráveis pela vontade própria. Na essência da distinção está o conceito de que as alucinações "verdadeiras", independentemente de qualquer outra característica, são sinal de doença mental. As alucinações, apresentaram uma incidência de 4-5% na população geral no estudo Epidemiologic Catchment Area. Estudos neuropatológicos recentes mostraram que alucinações ocorrem em sinucleinopatias e são um preditor significativo de depósitos de corpos de Lewy. Portanto, as alucinações são uma característica da doença de Parkinson e da demência com corpos de Lewy As alucinações são um sintoma não motor comum da doença de Parkinson, ocorrendo em até 44% dos pacientes. As alucinações visuais são em sua maioria complexas e cinemáticas; O insight preservado ou perturbado sobre a natureza das alucinações é um importante fator prognóstico, embora, eventualmente, todas as alucinações venham a apresentar-se num estado de insight reduzido. Teorias atuais sobre a origem das alucinações apontam para disfunção visual, overflow de sonhos e comprometimento cognitivo, mas objeções pode ser levantada para cada um dos modelos. A compreensão da origem das alucinações é necessária para o desenvolvimento de tratamentos: todas as avaliações dos tratamentos foram focadas na psicose, e somente a clozapina obteve avaliações baseadas em evidências positivas sobre a eficácia. No entanto, é provável que os inibidores de colinesterase, antipsicóticos e agentes anti-5-hidroxitriptamina3 e drogas que atuam na regulação do sono tenham efeitos diferentes e talvez opostos em diferentes tipos de alucinações, sejam eles acompanhados por insight perturbado, distúrbios do sono ou outras características psicóticas. As alucinações visuais no início do curso de uma doença demencial são mais comuns na doença de corpos de Lewy cortical do que na doença de Alzheimer. As alucinações visuais em pacientes com doença de Alzheimer estão associadas a distúrbios comportamentais graves específicos. Além disso, a ocorrência de alucinações em indivíduos com doença de Alzheimer está associada a um rápido declínio cognitivo, distúrbios da linguagem, agressão e hostilidade. Uma vez que a presença de alucinações visuais em indivíduos com doença de Parkinson prediz demência, a necessidade de instituicionalização e subsequente mortalidade, a prevenção e tratamento vigoroso de alucinações é de grande relevância nesta patologia assim como nas outras doenças neurodegenerativas. A pesquisa bibliográfica foi realizada nas seguintes bases de dados: Medline / PubMed, Medscape, E-medicine, além de diversos livros de referência sobre a especialidade. Esta pesquisa foi realizada em inglês. Após uma pesquisa detalhada, podemos apontar que as alucinações têm grande importância dado que predizem uma maior taxa de mortalidade e complicações em doenças neurodegenerativas, especialmente Parkinson. Portanto, é de suma relevância investigar melhor a fisiopatologia das alucinações, a fim de ter um tratamento eficiente para elas.By definition, true hallucinations are conceived of as indistinguishable from real perceptions except that there is no stimulus. For these purposes, a real perception occurs in external objective space, has a character of objectivity, is received by the person experiencing it with an attitude of passivity, and the sensory elements which are full, fresh, and constant are unalterable by individual will. (1) At the heart of the distinction is the notion that ‘true’ hallucinations, irrespective of any other feature, signal serious mental illness. (1) Hallucinations, a common experience, exhibited an incidence of 4-5% in the general population in the Epidemiologic Catchment Area study. (2) Recent neuropathological studies showed that hallucinations occur in synucleinopathies and are a significant predictor of Lewy Body depositions. Therefore, hallucinations are a hallmark of Parkinson’s disease and of Dementia with Lewy bodies. (3) Hallucinations are a common non motor symptom of Parkinson’s disease (PD), occurring in as many as 44% of patients. Visual hallucinations are mostly complex and kinematic; preserved or disturbed insight on the nature of hallucinations is a major prognostic factor, although eventually all hallucinations will present with reduced insight. (3,4) Current theories on the origin of hallucinations point to visual dysfunction, dream overflow, and cognitive impairment, yet objection can be raised on each one of the models. Understanding of the origin of hallucinations is required in order to develop treatments: all treatments evaluations were focused in general on psychosis, and only clozapine obtained positive evidence-based ratings on efficacy. (3,4) However, it is likely that cholinesterase inhibitors, antipsychotics and anti-5-hydroxytryptamine3 agents and drugs acting on sleep regulation will have different and perhaps opposite effects on different types of hallucinations, whether they are accompanied by disturbed insight, sleep disorders or other psychotic features. (3) Visual hallucinations early in the course of a dementing illness are more common in cortical Lewy body disease than in Alzheimer's disease. Visual hallucinations in persons with Alzheimer's disease are associated with specific serious behavioral disturbances. Additionally, the occurrence of hallucinations in individuals with Alzheimer's disease is associated with rapid cognitive decline, receptive language disorders, aggression, and hostility. (2) Since the presence of visual hallucinations in individuals with Parkinson’s disease predicts dementia, permanent nursing home placement, and subsequent mortality, prevention and vigorous treatment of hallucinations is needed. (2,4,5) The literature search was performed using the following databases: Medline/PubMed, Medscape, E-medicine as well as several reference books on the specialty. This research was conducted in English. After a detailed research we can point out that hallucinations have greater importance as they predict mortality and complications in neurodegenerative disease especially Parkinson’s. Therefore, it is of the utmost relevance to further investigate the pathophysiology of the hallucinations in order to have an efficient treatment for them

Physical properties and chemical composition of the cores in the California molecular cloud

We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation. We made a high-resolution column density map (18.2") with Herschel data, and extracted a complete sample of the cores in the CMC with the \textsl{fellwalker} algorithm. We performed new single-pointing observations of molecular lines near 90 GHz with the IRAM 30m telescope along the main filament of the CMC. In addition, we also performed a numerical modeling of chemical evolution for the cores under the physical conditions. We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51\% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index $\alpha=-0.9\pm 0.1$ that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency ($\varepsilon$) from the prestellar core to the star of $15\pm 1\%$ and the core formation efficiency (CFE) of 5.5\%, we suggest an overall star formation efficiency of about 1\% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [$\rm {HCO}^{+}$]/[HNC] and [$\rm {HCO}^{+}$]/$\rm [N_{2}H^{+}]$ in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is $\sim 5\times 10^4$~years.Comment: Accepted by Astronomy & Astrophysics (A&A

Tratamento cirúrgico do linfedema peno-escrotal

PURPOSE: Lymphedema of the penis and scrotum, regardless of its etiology, is determined by reduced lymphatic flow with subsequent enlargement of the penis and scrotum. The clinical course of this condition is characterized by extreme discomfort for patients, with limitation of local hygiene, ambulation, sexual intercourse, and voiding in the standing position. The purpose of the present study is to present the experience and results of the treatment of lymphedema of the penis and scrotum by removing affected tissues and correcting the penoscrotal region. MATERIALS AND METHODS: Seventeen patients with lymphedema of the penis and scrotum were treated with a modified Charles procedure, which consists of the excision of the affected skin followed by scrotoplasty and midline suture simulating the scrotal raphe. The penis is covered with a split-thickness skin graft by means of a zigzag suture on its ventral surface. RESULTS: Regression of symptoms and improvement of previous clinical conditions were verified in the follow-up which ranged from 6 months to 6 years. One patient who had undergone lymphadenectomy with radiation therapy due to penile cancer had recurrent scrotum lymphedema. CONCLUSIONS: The modified Charles procedure for the treatment of penoscrotal lymphedema is easily reproducible and allows better local hygiene, easier ambulation, voiding in the standing position, resuming sexual intercourse, and finally, better cosmetic results in the affected area with remarkable improvement in quality of life.INTRODUÇÃO: O linfedema peno-escrotal, independentemente da etiologia, é determinado pela redução do fluxo linfático com conseqüente aumento do volume do escroto e pênis. A evolução clínica da doença é caracterizada com extremo desconforto ao paciente, limitando a higiene local, a deambulação, o intercurso sexual e a micção em posição ortostática. OBJETIVO: Apresentar a experiência e resultados no tratamento da patologia com remoção dos tecidos comprometidos e correção peno-escrotal. MÉTODO: Foram tratados 17 pacientes com linfedema do escroto e pênis com a técnica de Charles modificada, que consiste na excisão da pele comprometida seguida de escrotoplastia e sutura mediana simulando a rafe escrotal. O pênis é recoberto com enxerto de pele parcial suturado em linha quebrada na face ventral. RESULTADOS: No seguimento dos pacientes, que variou entre 6 meses e 6 anos, constatou-se regressão dos sintomas e melhora das condições clínicas prévias. Um paciente submetido à linfadenectomia com radioterapia por câncer de pênis teve recidiva do linfedema escrotal. CONCLUSÃO: A técnica de Charles modificada no tratamento do linfedema peno-escrotal é facilmente reprodutível e possibilita com seus resultados melhor higiene local, melhor movimentação, micção em posição ortostática, retomada do intercurso sexual e, finalmente, melhor aparência à região comprometida com franca melhora da qualidade de vida

Evaluation of the diagnostic potential of CD1a immunohistochemistry for visceral leishmaniasis

Visceral Leishmaniasis is a public health problem caused by protozoans of the genus Leishmania. K39 serological test is commonly used in the initial investigation, with high specificity, but variable sensitivity. Amastigotes can be identified by optical microscopy, however, the differential diagnosis with cellular debris or other intracellular parasites is necessary. Recent studies have raised the possibility of using immunohistochemistry in the diagnosis of visceral leishmaniasis with labeling of amastigotes by the anti-CD1a antibody. This retrospective study was based on 38 samples from patients with visceral leishmaniasis whose diagnoses were confirmed by myelogram and/or k39 testing, aside from positive (N=13) and negative biopsies (N=25), 2 samples from patients with false positive biopsies for visceral leishmaniasis and 8 samples from patients with histoplasmosis diagnosis. The histological slides were evaluated for the presence of amastigotes and their Modified Ridley Parasitic Index. The samples were submitted to immunohistochemical reactions using the anti-CD1a antibody with MTB1 and O10 clones. Immunohistochemical reactions with MTB1 and O10 clones had low sensitivity in this study. However, all bone marrow samples were previously decalcified with nitric acid which is probably a deleterious treatment for immunohistochemical reactions in this site. Excluding these samples, we obtained 58.33% sensitivity and 100% specificity with the MTB1 clone. Despite the intermediate sensitivity, the immunohistochemistry for the CD1a marker with clone MTB1 can be useful in the differential diagnosis of visceral leishmaniasis, helping to discriminate leishmania amastigotes from other pathogens with similar morphology and cellular debris in different samples, except in bone marrow biopsies previously decalcified with nitric acid

Phenology and Seasonal Ecosystem Productivity in an Amazonian Floodplain Forest

everal studies have explored the linkages between phenology and ecosystem productivity across the Amazon basin. However, few studies have focused on flooded forests, which correspond to c.a. 14% of the basin. In this study, we assessed the seasonality of ecosystem productivity (gross primary productivity, GPP) from eddy covariance measurements, environmental drivers and phenological patterns obtained from the field (leaf litter mass) and satellite measurements (enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer/multi-angle implementation correction (MODIS/MAIAC)) in an Amazonian floodplain forest. We found that ecosystem productivity is limited by soil moisture in two different ways. During the flooded period, the excess of water limits GPP (Spearman’s correlation; rho = −0.22), while during non-flooded months, GPP is positively associated with soil moisture (rho = 0.34). However, GPP is maximized when cumulative water deficit (CWD) increases (rho = 0.81), indicating that GPP is dependent on the amount of water available. EVI was positively associated with leaf litter mass (Pearson’s correlation; r = 0.55) and with GPP (r = 0.50), suggesting a coupling between new leaf production and the phenology of photosynthetic capacity, decreasing both at the peak of the flooded period and at the end of the dry season. EVI was able to describe the inter-annual variations on forest responses to environmental drivers, which have changed during an observed El Niño-Southern Oscillation (ENSO) year (2015/2016)

Physical-Layer Security of SIMO Communication Systems over Multipath Fading Conditions

The present work investigates the physical layer security of wireless communication systems over non-homogeneous fading environments, i.e. $and$ fading models, which are typically encountered in realistic wireless transmission scenarios in the context of conventional and emerging communication systems. This study considers a single-input multiple-output system that consists of a single-antenna transmitter, a multi-antenna legitimate receiver, and an active multiantenna eavesdropper. To this end, novel exact analytic expressions are derived for the corresponding average secrecy capacity and secrecy outage probability, which are corroborated by respective results from computer simulations. Capitalizing on the offered results, the physical layer security is quantified in terms of different parameters, which leads to useful insights on the impact of non-homogeneous fading environment and the number of employed antennas on the achieved physical layer security levels of the underlying system configuration. The offered results and insights are useful for the design of such systems as well as for the computational requirements and sustainability relating to such systems, since emerging communications are largely characterized by stringent quality of service and complexity requirements.acceptedVersionPeer reviewe

Congenital aplasia of the optic chiasm and esophageal atresia: a case report

<p>Abstract</p> <p>Introduction</p> <p>The complete absence of the chiasm (chiasmal aplasia) is a rare clinical condition. Hypoplasia of the optic nerve and congenital nystagmus are almost invariably associated characteristics. Microphthalmos or anophthalmos are common features in chiasmal aplasia, while central nervous system abnormalities are less frequent. Esophageal atresia can be isolated or syndromic. In syndromic cases, it is frequently associated with cardiac, limb, renal or vertebral malformations and anal atresia. More rarely, esophageal atresia can be part of anophthalmia-esophageal-genital syndrome, which comprises anophthalmia or microphthalmia, genital abnormalities, vertebral defects and cerebral malformations. Here, a previously unreported case of chiasmal aplasia presenting without microphthalmos and associated with esophageal atresia is described.</p> <p>Case presentation</p> <p>Aplasia of the optic chiasm was identified in a Caucasian Italian 8-month-old boy with esophageal atresia. An ultrasound examination carried out at 21 weeks' gestation revealed polyhydramnios. Intrauterine growth retardation, esophageal atresia and a small atrial-septal defect were subsequently detected at 28 weeks' gestation. Repair of the esophageal atresia was carried out shortly after birth. A jejunostomy was carried out at four months to facilitate enteral feeding. The child was subsequently noted to be visually inattentive and to be neurodevelopmentally delayed. Magnetic resonance imaging revealed chiasmal aplasia. No other midline brain defects were found. His karyotype was normal.</p> <p>Conclusion</p> <p>If achiasmia is a spectrum, our patient seems to depict the most severe form, since he appears to have an extremely severe visual impairment. This is in contrast to most of the cases described in the literature, where patients maintain good--or at least useful-- visual function. To the best of our knowledge, the association of optic nerve hypoplasia, complete chiasmal aplasia, esophageal atresia and atrial-septal defect, choanal atresia, hypertelorism and psychomotor retardation has never been described before.</p

The N∗ Fisher-Snedecor F Cascaded Fading Model

The Fisher-Snedecor F distribution was recently proposed as an accurate and tractable composite fading model in the context of device-to-device communications. The present work derives the product of the Fisher-Snedecor F composite fading model, which is useful in characterizing fading effects in numerous realistic communication scenarios. To this end, novel analytic expressions are first derived for the probability density function, the cumulative distribution function and the moment of the product of N statistically independent, but not necessarily identically distributed, Fisher-Snedecor F random variables. Capitalizing on these expressions, we derive tractable closed-form expressions for channel quality estimation of the proposed model as well as the corresponding outage probability and average bit error probability for binary modulations. The offered results are corroborated by extensive Monte-Carlo simulation results, which verify the validity of the derived expressions. It is shown that the number of cascaded channels affects considerably the corresponding performance, as a variation of over an order of magnitude is observed across all signal-to-noise ratio regimes