Fundamental tone estimates for elliptic operators in divergence form and geometric applications.

Abstract:

:We establish a method for giving lower bounds for the fundamental tone of elliptic operators in divergence form in terms of the divergence of vector fields. We then apply this method to the Lr operator associated to immersed hypersurfaces with locally bounded (r + 1)-th mean curvature Hr + 1 of the space forms Nn+ 1(c) of constant sectional curvature c. As a corollary we give lower bounds for the extrinsic radius of closed hypersurfaces of Nn+ 1(c) with Hr + 1 > 0 in terms of the r-th and (r + 1)-th mean curvatures. Finally we observe that bounds for the Laplace eigenvalues essentially bound the eigenvalues of a self-adjoint elliptic differential operator in divergence form. This allows us to show that Cheeger's constant gives a lower bounds for the first nonzero Lr-eigenvalue of a closed hypersurface of Nn+ 1(c).

journal_name

An Acad Bras Cienc

authors

Bessa GP,Jorge LP,Lima BP,Montenegro JF

doi

10.1590/s0001-37652006000300001

subject

Has Abstract

pub_date

2006-09-01 00:00:00

pages

391-404

issue

3

eissn

0001-3765

issn

1678-2690

pii

S0001-37652006000300001

journal_volume

78

pub_type

杂志文章
  • An integrated approach clarifies the cryptic diversity in Hypostomus Lacépède 1803 from the Lower La Plata Basin.

    abstract::Hypostomus commersoni Valenciennes 1836, Hypostomus cordovae (Günther 1880) and Hypostomus laplatae (Eigenmann 1907) have been little studied since their original descriptions. This study shows a comprehensive review of these species from the Lower La Plata Basin, including their taxonomic history, distribution, color...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201920180131

    authors: Cardoso YP,Brancolini F,Protogino L,Paracampo A,Bogan S,Posadas P,Montoya-Burgos JI

    更新日期:2019-01-01 00:00:00

  • Extremum Seeking-based Adaptive PID Control applied to Neuromuscular Electrical Stimulation.

    abstract::A multivariable deterministic extremum seeking (ES) is being evaluated to construct an adaptive Proportional-Integral-Derivative (PID) control law for the functional Neuromuscular Electrical Stimulation (NMES) of stroke patients. The developed scheme is applied to control the position of the patient's arm so that move...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201820180544

    authors: Roux-Oliveira T,Costa LR,Pino AV,Paz P

    更新日期:2019-02-14 00:00:00

  • Aedeagus morphology as a discriminant marker in two closely related cactophilic species of Drosophila (Diptera; Drosophilidae) in South America.

    abstract::Drosophila serido and D. antonietae are sibling species belonging to the Drosophila buzzatii cluster. Morphologically, they can only be discriminated by quantitative traits. In this paper we analyze the length and equalized average curvature of four regions of the aedeagus of D. antonietae and D. serido. Specimens of ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652006000200002

    authors: Franco FF,Prado PR,Sene FM,Costa LF,Manfrin MH

    更新日期:2006-06-01 00:00:00

  • DNA damage in children and adolescents with cardiovascular disease risk factors.

    abstract::The risk of developing cardiovascular disease (CVD) is related to lifestyle (e.g. diet, physical activity and smoking) as well as to genetic factors. This study aimed at evaluating the association between CVD risk factors and DNA damage levels in children and adolescents. Anthropometry, diet and serum CVD risk factors...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652012005000039

    authors: Kliemann M,Prá D,Müller LL,Hermes L,Horta JA,Reckziegel MB,Burgos MS,Maluf SW,Franke SI,Silva Jd

    更新日期:2012-09-01 00:00:00

  • A new species and new records of Leptogium (Ach.) Gray (Collemataceae, Peltigerales) from Rio Grande do Sul State with an identification key for the genus.

    abstract::Specimens of Leptogium collected in ten localities from the State of Rio Grande do Sul were studied. Sixteen species were found of 28 records mentioned to the state, which represents around 57% of the Leptogium diversity known for Rio Grande do Sul. Leptogium exaratum is proposed as a new species. Leptogium atlanticum...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201920180313

    authors: Kitaura MJ,Koch NM,Lucheta F,Käffer MI,Schmitt JL,Pedroso J,Martins SA,Rodrigues AS,Canêz LS

    更新日期:2019-02-14 00:00:00

  • Molecular characterization of Moenkhausia (Pisces: Characiformes) populations with different lateral line developmental levels.

    abstract::The genera Hemigrammus and Moenkhausia have been traditionally diagnosed mainly by the former having lateral line completely pored whereas the latter having a lateral line with a few pored scales. Those features have been used to diagnose species of both genera in the upper Paraná River floodplain. Specimens with the ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201820170493

    authors: Mota TFM,Fabrin TMC,Deprá GC,Gasques LS,Oliveira AV,Pavanelli CS,Prioli SMAP,Prioli AJ

    更新日期:2018-07-01 00:00:00

  • Karyotypic analysis in species of the genus Dasyprocta (Rodentia: Dasyproctidae) found in Brazilian Amazon.

    abstract::A total of 30 animals of the genus Dasyprocta were cytogenetically studied. They belong to the following species: D. prymnolopha (N=20), D. leporina (N=6), D. fuliginosa (N=1) and Dasyprocta sp. (N=3) (Dasyproctidae, Hystricognathi). Cell suspensions were obtained by peripheral blood culture, besides bone marrow and s...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652003000100007

    authors: Ramos RS,Vale WG,Assis FL

    更新日期:2003-03-01 00:00:00

  • S-(+)- and R-(-)-linalool: a comparison of the in vitro anti-Aeromonas hydrophila activity and anesthetic properties in fish.

    abstract::Linalool is the main compound of many essential oils and occurs in two isomeric forms: S-(+)- and R-(-)-linalool. This study aimed to determine if linalool isomers have different antimicrobial and anesthetic properties in fish. For this purpose, these compounds were previously isolated from Lippia alba (Mill.)N. E. Br...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201720150643

    authors: Silva LL,Balconi LS,Gressler LT,Garlet QI,Sutili FJ,Vargas APC,Baldisserotto B,Morel AF,Heinzmann BM

    更新日期:2017-01-01 00:00:00

  • Electrocyte physiology: I. Temperature dependence of membrane excitability.

    abstract::Some membrane characteristics of the isolated electrocyte of the Sachs organ are presented as function of temperature. Excitability curves are shown for electrocytes kept in standard saline at different temperatures. It is shown that rheobase varies directly with temperature. Apparently membrane resistance varies from...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:

    authors: Esquibel MA,Negreiros J,Gawryszewski LG

    更新日期:1980-09-01 00:00:00

  • High prevalence of unusual genotypes of Toxoplasma gondii infection in pork meat samples from Erechim, Southern Brazil.

    abstract::Toxoplasmosis is the most common cause of infectious uveitis in Brazil, with a higher frequency in the South of the country. We have collected samples from porcine tongue and diaphragm obtained in both large and small abattoirs and used molecular biological technique to determine the prevalence of infection and RFLP a...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652007000100013

    authors: Belfort-Neto R,Nussenblatt V,Rizzo L,Muccioli C,Silveira C,Nussenblatt R,Khan A,Sibley LD,Belfort R Jr

    更新日期:2007-03-01 00:00:00

  • [The use of tapioca as coverage in viral titration].

    abstract::Virus titration is an important step required on viral vaccines quality control. "Plaque assay", which employs several types of overlay media, is usually used on viral titrations. In this paper we describe the use of Tapioca as an overlay media. Firstly, the toxicity of Tapioca was tested on Vero cells inoculated or n...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:

    authors: Post PR,de Carvalho R,Brito EC,Galler R

    更新日期:1992-01-01 00:00:00

  • Evaluation of the catalytic activity of lipases immobilized on chrysotile for esterification.

    abstract::In the present work, the ester synthesis in organic media catalyzed by lipases immobilized on chrysotile was studied. Lipases of different sources (Mucor javanicus, Pseudomonas cepacia, Rhizopus oryzae, Aspergillus niger and Candida rugosa) were immobilized on chrysotile, an inexpensive magnesium silicate, and used fo...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652003000200003

    authors: Silva JE,Jesus PC

    更新日期:2003-06-01 00:00:00

  • Scientists in the public sphere: Interactions of scientists and journalists in Brazil.

    abstract::In order to map scientists' views on media channels and explore their experiences interacting with journalists, the authors conducted a survey of about 1,000 Brazilian scientists. Results indicate that scientists have clear and high expectations about how journalists should act in reporting scientific information in t...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201620150558

    authors: Massarani L,Peters HP

    更新日期:2016-06-07 00:00:00

  • Characterization, fractionation and mobility of trace elements in surface sediments of the Jequiezinho River, Bahia, Brazil.

    abstract::The Jequiezinho River is a temporary river. In the urban stretch it is impacted, with perennial flow coming from domestic sewage and rainwater. This study evaluated the geochemical distribution and potential mobility of some metals (Pb, Co, Ca, Cr, Mg, Cu, Fe, Mn, Ni and Zn) in sediments of the Jequiezinho River. Sedi...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765202020190558

    authors: Silva DS,Cerqueira UMFM,Aguiar RM,Carneiro PLS,Bezerra MA

    更新日期:2020-11-27 00:00:00

  • Food restriction beginning at lactation interferes with the cellular dynamics of the mucosa and colonic myenteric innervation in adult rats.

    abstract::The effects of food restriction (FR) on the morphoquantitative aspects of the wall and myenteric neurons of the proximal colon in adult rats were analysed. FR was imposed by duplication of the experimental brood size in relation to the control brood during lactation. The FR group received a 50% reduction of food from ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201420140163

    authors: Schoffen JP,Vicentini FA,Marcelino CG,Araújo EJ,Pedrosa MM,Natali MR

    更新日期:2014-12-01 00:00:00

  • Partum and postpartum characteristics on the postpartum rebreeding in beef cattle.

    abstract::The objective was to evaluate the influence of calving and postpartum characteristics, measured in different genetic predominance, on the postpartum rebreeding. Were evaluated 437 partum from cows that received feeding management consisting of a forage base of the native field and the mating season consisted of 90 day...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201820171005

    authors: Joner G,Alves Filho DC,Brondani IL,Borchate D,Klein JL,Domingues CC,Rodrigues LS,Machado DS

    更新日期:2018-08-01 00:00:00

  • Influence of land use changes on water chemistry in streams in the State of São Paulo, southeast Brazil.

    abstract::Streamwater is affected by several processes in the watershed including anthropogenic activities that result in changes in water quality as well as in the functioning of these stream ecosystems. Therefore, this work aims to evaluate the concentration of major ions (Ca(2+), Mg(2+), Na(+), K(+), NH4(+), NO3(-), NO2(-), ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652012000400007

    authors: Silva DM,Camargo PB,McDowell WH,Vieira I,Salomão MS,Martinelli LA

    更新日期:2012-12-01 00:00:00

  • Short-term low-protein diet during pregnancy alters islet area and protein content of phosphatidylinositol 3-kinase pathway in rats.

    abstract::The phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways mediate β cell growth, proliferation, survival and death. We investigated whether protein restriction during pregnancy alters islet morphometry or the expression and phosphorylation of several proteins involved in the phosphatidylinositol ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201520140251

    authors: Salvatierra CS,Reis SR,Pessoa AF,De Souza LM,Stoppiglia LF,Veloso RV,Reis MA,Carneiro EM,Boschero AC,Colodel EM,Arantes VC,Latorraca MQ

    更新日期:2015-04-01 00:00:00

  • Reproductive success of South American terns (Sterna hirundinacea) from Cardos Islands, Florianópolis, SC, Brazil.

    abstract::Sterna hirundinacea (Lesson, 1831) is a migratory seabird that breeds in the Pacific Coast (from Peru to Chile) and along the Atlantic coast of South America from Espírito Santo (Brazil) to Terra del Fuego (Argentina). This paper describes the reproductive success of South American Terns on Cardos Island, Florianopoli...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652012005000020

    authors: Fracasso HA,Branco JO

    更新日期:2012-06-01 00:00:00

  • Anti-urolithiatic activity of Salvia hispanica L. seeds in ethylene glycol induced urolithiasis rat's model.

    abstract::Urolithiasis is a disorder of kidneys in which stones formation occur due to the excessive deposition of minerals in the urinary tract. It affects 12% of the population worldwide. Salvia hispanica seeds are rich source of quercetin which has preventive role in renal stone formation. The study objective was to explore ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765202020200067

    authors: Saleem U,Ahmad N,Shah MA,Anwar F,Ahmad B

    更新日期:2020-11-16 00:00:00

  • Ameliorative potential of Ocimum sanctum in chronic constriction injury-induced neuropathic pain in rats.

    abstract::The present study was designed to investigate the ameliorative potential of Ocimum sanctum and its saponin rich fraction in chronic constriction injury-induced neuropathic pain in rats. The chronic constriction injury was induced by placing four loose ligatures around the sciatic nerve, proximal to its trifurcation. T...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201520130008

    authors: Kaur G,Bali A,Singh N,Jaggi AS

    更新日期:2015-03-01 00:00:00

  • Ultra-low temperature conservation of Brazilian pine embryogenic cultures.

    abstract::This study aimed to establish a cryopreservation protocol for embryogenic cultures of A. angustifolia, enabling the ex situ conservation of the species. Embryogenic cultures were established from immature seeds and treated with variations of the cryoprotectant solutions SuDG, SoD and PVS2 prior to immersion in liquid ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201420130405

    authors: Demarchi G,Stefenon VM,Steiner N,Vieira FN,Dal Vesco LL,Guerra MP

    更新日期:2014-12-01 00:00:00

  • Influence of tides and winds on fishing techniques and strategies in the Mamanguape River Estuary, Paraíba State, NE Brazil.

    abstract::This work was carried out in two small fishing communities, Barra de Mamanguape and Tramataia, Northeastern Brazil. The aim was to study these traditional fishermen's knowledge and perception about tide and wind classifications, as well as their fishing strategies and techniques. Our research methodology involved vari...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652012005000046

    authors: Bezerra DM,Nascimento DM,Ferreira EN,Rocha PD,Mourão JS

    更新日期:2012-09-01 00:00:00

  • Mangroves Response to Climate Change: A Review of Recent Findings on Mangrove Extension and Distribution.

    abstract::Mangroves function as a natural coastline protection for erosion and inundation, providing important environmental services. Due to their geographical distribution at the continent-ocean interface, the mangrove habitat may suffer heavy impacts from global climate change, maximized by local human activities occurring i...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201520150055

    authors: Godoy MD,de Lacerda LD

    更新日期:2015-04-01 00:00:00

  • Effect of essential oil from Citrus aurantium in maternal reproductive outcome and fetal anomaly frequency in rats.

    abstract::Citrus aurantium L., commonly known as bitter orange, is widely used in folk medicine, but there is little data in the literature about the effects on pregnancy. The aim of the present study was to evaluate the influence of essential oil obtained from fruits of Citrus aurantium on the maternal reproductive outcome and...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201520140354

    authors: Volpato GT,Francia-Farje LA,Damasceno DC,Oliveira RV,Hiruma-Lima CA,Kempinas WG

    更新日期:2015-03-01 00:00:00

  • Uncertainties Associated with Arithmetic Map Operations in GIS.

    abstract::Arithmetic map operations are very common procedures used in GIS to combine raster maps resulting in a new and improved raster map. It is essential that this new map be accompanied by an assessment of uncertainty. This paper shows how we can calculate the uncertainty of the resulting map after performing some arithmet...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201820170589

    authors: Yamamoto JK,Kikuda AT,Rampazzo GJ,Leite CBB

    更新日期:2018-08-01 00:00:00

  • D-Pinitol Increases Insulin Secretion and Regulates Hepatic Lipid Metabolism in Msg-Obese Mice.

    abstract::D-pinitol is one of the major inositol found in plants and studies suggest its potential hypoglycemic and hypolipidemic actions in diabetic rodents. Here, we investigated the actions of D-pinitol on adiposity, and in lipid and glycemic homeostasis in monosodium glutamate (MSG)-obese mice. Swiss mice received daily sub...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765202020201382

    authors: Silva JÚnior JAD,Silva ACVFD,Figueiredo LS,Araujo TR,Freitas IN,Carneiro EM,Ribeiro ES,Ribeiro RA

    更新日期:2020-11-20 00:00:00

  • Metabolic responses to dietary carbohydrate/lipids ratios in neotropical hybrid catfish (♂Pseudoplatystoma corruscans×♀Pseudoplatystoma fasciatum).

    abstract::The purpose of this study was to assess the effect of different carbohydrate and lipid (CHO/L) ratios on the performance and energy metabolism of hybrid catfish (♂Pseudoplatystoma corruscans × ♀ Pseudoplatystoma fasciatum). One hundred and sixty-eight fish (104.9±16.5 g BW) were distributed into 24 100-L tanks. The ex...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/0001-3765201920190075

    authors: Okamura D,Fortes-Silva R,Paulino RR,Araújo FG,Costa DVD,Pereira RT,Rosa PV

    更新日期:2019-11-25 00:00:00

  • The eolianites between Sanga do Cabral and Botucatu formations in Rio Grande do Sul State, Brazil.

    abstract::This paper discusses the facies distribution of Mesozoic eolian sandstones between the Sanga do Cabral and Botucatu formations and also their contact relationships, in São Leopoldo area, State of Rio Grande do Sul (RS), southern Brazil. The main distinctive characteristics regarding these sandstones and formations are...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652000000200010

    authors: Nowatzki CH,Kern HP

    更新日期:2000-06-01 00:00:00

  • Immature stages of Spodoptera albula (Walker) (Lepidoptera: Noctuidae): developmental parameters and host plants.

    abstract::This study aimed to detail the temporal and morphological parameters of the immature stages of Spodoptera albula (Walker 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase) and to gather information about their larval host plants. For this purpose, a new rearing method and artificial diet ...

    journal_title:Anais da Academia Brasileira de Ciencias

    pub_type: 杂志文章

    doi:10.1590/s0001-37652013000100013

    authors: Montezano DG,Specht A,Bortolin TM,Fronza E,Sosa-Gómez DR,Roque-Specht VF,Pezzi P,Luz PC,Barros NM

    更新日期:2013-03-01 00:00:00