RESUMO
We perform a finite-time scaling analysis over the detrapping point of a three-state quantum walk on the line. The coin operator is parametrized by ρ that controls the wave packet spreading velocity. The input state prepared at the origin is set as a symmetric linear combination of two eigenstates of the coin operator with a characteristic mixing angle θ, one of them being the component that results in full spreading occurring at θ_{c}(ρ) for which no fraction of the wave packet remains trapped near the initial position. We show that relevant quantities, such as the survival probability and the participation ratio assume single parameter scaling forms at the vicinity of the detrapping angle θ_{c}. In particular, we show that the participation ratio grows linearly in time with a logarithmic correction, thus, shedding light on previous reports of sublinear behavior.
RESUMO
We study the spreading of SARS-CoV-2 in Brazil based on official data available since March 22, 2020. Calculations are done via an adaptive susceptible-infected-removed (SIR) model featuring dynamical recuperation and propagation rates. We are able reproduce the number of confirmed cases over time with less than 5% error and also provide with short- and long-term predictions. The model can also be used to account for the epidemic dynamics in other countries with great accuracy.
RESUMO
We study the effects of spatially long-range correlated phase disorder on the Hadamard quantum walk on a line. The shift operator is built to exhibit an intrinsic disorder distribution featuring long-range correlations. To impose such, we resort to fractional Brownian motion with power-law spectrum 1/k^{2α} with α≥0 being the exponent that controls the degree of correlations. We discuss the scaling behavior of the walker's wave packet and report a localization-delocalization transition controlled by α. We unveil two intermediate dynamical regimes between exponential localization and full delocalization.
RESUMO
In Brazil, the expansion of agricultural activity and the associated indiscriminate use of herbicides such as glyphosate is directly related to the loss of biodiversity in the Cerrado. The identification of plant species as bioindicators of herbicide action, especially species native to the area, can help in monitoring the impacts of xenobiotics in the remaining Cerrado. Thus, this study was designed to evaluate the possible use of the native Cerrado species Pouteria torta as a bioindicator of glyphosate action via changes in physiological performance. At 16 months after sowing, the effect of glyphosate was evaluated by applying the following doses: 0 (control), 25, 50, 100, 200, 400, 800, and 1200 g a.e. ha-¹. In response to glyphosate, P. torta exhibited reductions in photosynthesis and chloroplastid pigment content, as well as accumulation of shikimic acid and the occurrence of chlorosis and necrosis. These changes demonstrate the high sensitivity of P. torta to glyphosate and its potential for use as a bioindicator of this herbicide.(AU)
No Brasil, a expansão da atividade agrícola, aliada a utilização indiscriminada de herbicidas como o glyphosate, possui relação direta com a perda da biodiversidade no Cerrado. A identificação de espécies vegetais bioindicadoras da ação de herbicidas, particularmente as nativas do Cerrado, pode auxiliar em processos de monitoramento dos impactos desse xenobiótico nas remanescentes do Cerrado. Assim, este estudo foi projetado para avaliar o possível uso de Pouteria torta, espécie nativa do cerrado, como bioindicadora da ação do glyphosate via mudanças na sua performance fisiológica. Após 16 meses de semeadura, o efeito do glyphosate foi avaliado quando aplicadas as seguintes doses: 0 (controle), 25, 50, 100, 200, 400, 800 e 1200 g e. a. ha-1. Em reposta ao glyphosate, as plantas de P. torta apresentaram redução na sua performance do processo fotossintético e no conteúdo de pigmentos cloroplastídicos, além do acúmulo de ácido chiquímico e da ocorrência de cloroses e necroses. Essas alterações demonstram a alta sensibilidade de P. torta ao glyphosate, o que potencializa a sua utilização como bioindicadora da ação desse herbicida.(AU)
Assuntos
Pouteria/crescimento & desenvolvimento , Herbicidas/toxicidade , Biomarcadores Ambientais , Monitoramento Ambiental , Pradaria , BrasilRESUMO
Abstract In Brazil, the expansion of agricultural activity and the associated indiscriminate use of herbicides such as glyphosate is directly related to the loss of biodiversity in the Cerrado. The identification of plant species as bioindicators of herbicide action, especially species native to the area, can help in monitoring the impacts of xenobiotics in the remaining Cerrado. Thus, this study was designed to evaluate the possible use of the native Cerrado species Pouteria torta as a bioindicator of glyphosate action via changes in physiological performance. At 16 months after sowing, the effect of glyphosate was evaluated by applying the following doses: 0 (control), 25, 50, 100, 200, 400, 800, and 1200 g a.e. ha-1. In response to glyphosate, P. torta exhibited reductions in photosynthesis and chloroplastid pigment content, as well as accumulation of shikimic acid and the occurrence of chlorosis and necrosis. These changes demonstrate the high sensitivity of P. torta to glyphosate and its potential for use as a bioindicator of this herbicide.
Resumo No Brasil, a expansão da atividade agrícola, aliada a utilização indiscriminada de herbicidas como o glyphosate, possui relação direta com a perda da biodiversidade no Cerrado. A identificação de espécies vegetais bioindicadoras da ação de herbicidas, particularmente as nativas do Cerrado, pode auxiliar em processos de monitoramento dos impactos desse xenobiótico nas remanescentes do Cerrado. Assim, este estudo foi projetado para avaliar o possível uso de Pouteria torta, espécie nativa do cerrado, como bioindicadora da ação do glyphosate via mudanças na sua performance fisiológica. Após 16 meses de semeadura, o efeito do glyphosate foi avaliado quando aplicadas as seguintes doses: 0 (controle), 25, 50, 100, 200, 400, 800 e 1200 g e. a. ha-1. Em reposta ao glyphosate, as plantas de P. torta apresentaram redução na sua performance do processo fotossintético e no conteúdo de pigmentos cloroplastídicos, além do acúmulo de ácido chiquímico e da ocorrência de cloroses e necroses. Essas alterações demonstram a alta sensibilidade de P. torta ao glyphosate, o que potencializa a sua utilização como bioindicadora da ação desse herbicida.
Assuntos
Fotossíntese/efeitos dos fármacos , Pouteria/efeitos dos fármacos , Espécies Sentinelas/metabolismo , Herbicidas/efeitos adversos , Brasil , Relação Dose-Resposta a Droga , Glicina/efeitos adversosRESUMO
In Brazil, the expansion of agricultural activity and the associated indiscriminate use of herbicides such as glyphosate is directly related to the loss of biodiversity in the Cerrado. The identification of plant species as bioindicators of herbicide action, especially species native to the area, can help in monitoring the impacts of xenobiotics in the remaining Cerrado. Thus, this study was designed to evaluate the possible use of the native Cerrado species Pouteria torta as a bioindicator of glyphosate action via changes in physiological performance. At 16 months after sowing, the effect of glyphosate was evaluated by applying the following doses: 0 (control), 25, 50, 100, 200, 400, 800, and 1200 g a.e. ha-1. In response to glyphosate, P. torta exhibited reductions in photosynthesis and chloroplastid pigment content, as well as accumulation of shikimic acid and the occurrence of chlorosis and necrosis. These changes demonstrate the high sensitivity of P. torta to glyphosate and its potential for use as a bioindicator of this herbicide.
Assuntos
Glicina/análogos & derivados , Herbicidas/efeitos adversos , Fotossíntese/efeitos dos fármacos , Pouteria/efeitos dos fármacos , Espécies Sentinelas/metabolismo , Brasil , Relação Dose-Resposta a Droga , Glicina/efeitos adversos , Pradaria , Pouteria/metabolismo , GlifosatoRESUMO
We describe what is to our knowledge the first fatal case of central nervous system Enterovirus infection in Brazil. Molecular and phylogenetic characterization revealed that Enterovirus A was the aetiologic agent of this case.
RESUMO
Dyspnea, hunger for air, and urge to flee are the cardinal symptoms of panic attacks. Patients also show baseline respiratory abnormalities and a higher rate of comorbid and antecedent respiratory diseases. Panic attacks are also precipitated by infusion of sodium lactate and inhalation of 5% CO2 in predisposed patients but not in healthy volunteers or patients without panic disorder. Accordingly, Klein [Klein (1993) Arch Gen Psychiatry 50:306-317] suggested that clinical panic is the misfiring of an as-yet-unidentified suffocation alarm system. In rats, selective anoxia of chemoreceptor cells by potassium cyanide (KCN) and electrical and chemical stimulations of periaqueductal gray matter (PAG) produce defensive behaviors, which resemble panic attacks. Thus, here we examined the effects of single or combined administrations of CO2 (8% and 13%) and KCN (10-80 µg, i.v.) on spontaneous and PAG-evoked behaviors of rats either intact or bearing electrolytic lesions of PAG. Exposure to CO2 alone reduced grooming while increased exophthalmus, suggesting an arousal response to non-visual cues of environment. Unexpectedly, however, CO2 attenuated PAG-evoked immobility, trotting, and galloping while facilitated defecation and micturition. Conversely, KCN produced all defensive behaviors of the rat and facilitated PAG-evoked trotting, galloping, and defecation. There were also facilitatory trends in PAG-evoked exophthalmus, immobility, and jumping. Moreover, whereas the KCN-evoked defensive behaviors were attenuated or even suppressed by discrete lesions of PAG, they were markedly facilitated by CO2. Authors suggest that the PAG harbors an anoxia-sensitive suffocation alarm system which activation precipitates panic attacks and potentiates the subject responses to hypercapnia.
Assuntos
Asfixia/patologia , Substância Cinzenta Periaquedutal/patologia , Substância Cinzenta Periaquedutal/fisiopatologia , Análise de Variância , Animais , Comportamento Animal , Dióxido de Carbono/efeitos adversos , Cianatos/farmacologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Estimulação Elétrica , Reação de Fuga/efeitos dos fármacos , Reação de Fuga/fisiologia , Reação de Congelamento Cataléptica/efeitos dos fármacos , Reação de Congelamento Cataléptica/fisiologia , Modelos Logísticos , Masculino , Substância Cinzenta Periaquedutal/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
Relata-se um surto de doença exantemática, caracterizada como varíola bovina, acometendo bovinos e seres humanos na Zona da Mata Mineira. Setenta e duas propriedades, distribuídas em 20 municípios localizados na região, foram visitadas para se levantar os aspectos clínicos e epidemiológicos da doença. Detectaram-se 1020 vacas doentes durante a investigação, quando houve queda na produção do leite associada a infecções bacterianas secundárias. Casos humanos foram registrados em 83 por cento das propriedades visitadas. Espécimes clínicos e amostras de soro foram coletados dos animais doentes ou convalescentes. O diagnóstico de laboratório mostrou o envolvimento de um ortopoxvírus, precisamente o Vaccinia virus como agente etiológico do surto.
Assuntos
Humanos , Animais , Bovinos , Varíola Bovina/epidemiologia , Vaccinia virus/isolamento & purificaçãoRESUMO
Relata-se um surto de doença exantemática, caracterizada como varíola bovina, acometendo bovinos e seres humanos na Zona da Mata Mineira. Setenta e duas propriedades, distribuídas em 20 municípios localizados na região, foram visitadas para se levantar os aspectos clínicos e epidemiológicos da doença. Detectaram-se 1020 vacas doentes durante a investigação, quando houve queda na produção do leite associada a infecções bacterianas secundárias. Casos humanos foram registrados em 83% das propriedades visitadas. Espécimes clínicos e amostras de soro foram coletados dos animais doentes ou convalescentes. O diagnóstico de laboratório mostrou o envolvimento de um ortopoxvírus, precisamente o Vaccinia virus como agente etiológico do surto.(AU)
It was investigated an outbreak of exantemal disease in human and cattle in Zona da Mata region, Minas Gerais's State, Brazil. Seventy two farms located in 20 counties locating in this region were visited and disease pattern was studied. 1020 cows got sick in the visited herds and in 83% of them human cases occurred together with disease in animals. Drop in milk production and secondary infection were frequently observed. The disease occurred mainly from may to September. Serum and scars from sick and convalescent animals were collected and laboratory diagnostic showed that an orthopoxvirus, more precisely vaccinia virus was involved in the outbreak.(AU)
Assuntos
Animais , Humanos , Varíola Bovina/epidemiologia , Vaccinia virus/isolamento & purificação , BovinosRESUMO
Outbreaks of Salmonella spp. gastro-enteritis in hospitals are of concern because of the increased susceptibility of patients and associated high morbidity. This study is a report of a nosocomial outbreak of Salmonella enteritidis associated with enteral nutrition. In December 1999, one sample of enteral feed tested positive for S. enteritidis. During the subsequent 6 weeks, eight cases of nosocomial salmonellosis occurred. Patients involved in the outbreak were aged 19-79 years (median = 36.5), and salmonella was isolated from the blood of two patients. All patients were receiving enteral nutrition at the time and all had diarrhoea. Three patients died. All 13 employees of the Nutrition Department were asymptomatic and their stool samples were negative. Environmental and water samples were also negative. The diet, however, contained lyophilized egg albumin. Molecular typing showed that the isolates of seven patients were indistinguishable from the one obtained from the enteral diet. It was thought that the nosocomial salmonellosis probably occurred due to the use of a commercial lyophilized diet. Another method of processing diets may be necessary to ensure patient safety.
Assuntos
Infecção Hospitalar/epidemiologia , Surtos de Doenças , Nutrição Enteral/efeitos adversos , Intoxicação Alimentar por Salmonella/epidemiologia , Salmonella enteritidis/isolamento & purificação , Adulto , Idoso , Anti-Infecciosos/farmacologia , Brasil/epidemiologia , Infecção Hospitalar/etiologia , Infecção Hospitalar/prevenção & controle , Farmacorresistência Bacteriana , Ovos/microbiologia , Feminino , Microbiologia de Alimentos , Liofilização , Hospitais Universitários , Humanos , Masculino , Prontuários Médicos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos , Intoxicação Alimentar por Salmonella/etiologia , Intoxicação Alimentar por Salmonella/prevenção & controle , Salmonella enteritidis/efeitos dos fármacosRESUMO
Capsular components of Cryptococcus neoformans induce several deleterious effects on T cells. However, it is unknown how the capsular components act on these lymphocytes. The present study characterized cellular and molecular events involved in immunoregulation of splenic CD4(+) T cells by C. neoformans capsular polysaccharides (CPSs). The results showed that CPSs induce proliferation of normal splenic CD4(+) T cells, but not of normal CD8(+) T or B lymphocytes. Such proliferation depended on physical contact between CPSs and viable splenic adherent cells (SAC) and CD40 ligand-induced intracellular signal transduction. The absence of lymphoproliferation after fixation of SAC with paraformaldehyde has discarded the hypothesis of a superantigen-like activation. The evaluation of a cytokine pattern produced by the responding CD4(+) T lymphocytes revealed that CPSs induce a dominant Th2 pattern, with high levels of IL-4 and IL-10 production and undetectable inflammatory cytokines, such as TNF-alpha and IFN-gamma. Blockade of CD40 ligand by relevant mAb down-regulated the CPS-induced anti-inflammatory cytokine production and abolished the enhancement of fungus growth in cocultures of SAC and CD4(+) T lymphocytes. Our findings suggest that CPSs induce proliferation and differentiation of normal CD4(+) T cells into a Th2 phenotype, which could favor parasite growth and thus important deleterious effects to the host.
Assuntos
Cryptococcus neoformans/imunologia , Ativação Linfocitária , Polissacarídeos/imunologia , Células Th2/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Ligante de CD40/fisiologia , Adesão Celular , Células Cultivadas , Cryptococcus neoformans/patogenicidade , Citocinas/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Baço/imunologiaRESUMO
A 55-year-old woman with chronic spinal subdural hematoma, diagnosed by magnetic resonance (MR) is presented. There was no coagulation defect, anticoagulant therapy, or trauma.
Assuntos
Hematoma Subdural , Doenças da Medula Espinal , Doença Crônica , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
We report two patients who presented with a dramatic recovery from severe sensorineural hearing loss after total surgical removal of cerebellopontine angle tumors (meningioma and jugular foramen neurinoma). The factors that differentiate these "non-acoustic tumors" in relation to the prognosis for hearing are discussed. A surgical approach that maintains the labyrinthine structure and preserves the arachnoid membrane of the superior cerebellopontine angle cistern during tumor removal is stressed.
Assuntos
Neoplasias Cerebelares/complicações , Ângulo Cerebelopontino , Perda Auditiva Neurossensorial/etiologia , Adulto , Idoso , Audiometria , Neoplasias Cerebelares/cirurgia , Ângulo Cerebelopontino/cirurgia , Feminino , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Masculino , Meningioma/complicações , Meningioma/cirurgia , Neurilemoma/complicações , Neurilemoma/cirurgia , Indução de RemissãoRESUMO
Ventriculoperitoneal or cyst-peritoneal shunts are the usual treatment for children with Dandy-Walker syndrome. A combined ventricular and cyst shunt is often necessary and, in some cases, multiple revisions have to be done. Two patients with this syndrome were treated with posterior fossa exploration and cyst fenestration after several shunt revisions. The procedure was well tolerated with good results in both cases. The patients' data and preliminary results are presented here.
Assuntos
Encefalopatias/cirurgia , Derivações do Líquido Cefalorraquidiano , Cistos/cirurgia , Síndrome de Dandy-Walker/cirurgia , Crânio/cirurgia , Encefalopatias/patologia , Ventrículos Cerebrais , Fossa Craniana Posterior , Cistos/patologia , Síndrome de Dandy-Walker/patologia , Feminino , Humanos , Lactente , Cavidade Peritoneal/cirurgia , ReoperaçãoRESUMO
A direct fistula between cerebral cortical arteries and venous channels may result in an impressive aneurysm-like, saccular dilation of the venous portion. We had the opportunity to treat two children with this rare arteriovenous malformation, with excellent results. The controversy on the classification and treatment of this pathology is discussed briefly.
Assuntos
Malformações Arteriovenosas/diagnóstico por imagem , Artérias Cerebrais , Veias Cerebrais , Aneurisma Intracraniano/diagnóstico por imagem , Adolescente , Malformações Arteriovenosas/complicações , Malformações Arteriovenosas/cirurgia , Pré-Escolar , Humanos , Aneurisma Intracraniano/etiologia , Aneurisma Intracraniano/cirurgia , Masculino , Tomografia Computadorizada por Raios XRESUMO
The authors describe two patients with the association of polyposis-coli and central nervous system tumor (Turcot's syndrome). Clinical, genetic and therapeutic aspects are discussed.
Assuntos
Polipose Adenomatosa do Colo/cirurgia , Neoplasias Encefálicas/cirurgia , Glioblastoma/cirurgia , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Adolescente , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Feminino , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , ReoperaçãoRESUMO
An 88-year-old man was found at laminectomy to have an encapsulated spinal epidural hematoma. The surgical result was gratifying and reinforced a recent statement that spinal surgical procedures in the very elderly should not be withheld on the basis of age alone. Moreover, the rarity of this pathology in this age group and the clear identification of the lesion on the computed tomography scan of this case are to be noted.