Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sensors (Basel) ; 22(7)2022 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-35408240

RESUMO

The automatic positioning of machines in a large number of application areas is an important aspect of automation. Today, this is often done using classic geodetic sensors such as Global Navigation Satellite Systems (GNSS) and robotic total stations. In this work, a stereo camera system was developed that localizes a machine at high frequency and serves as an alternative to the previously mentioned sensors. For this purpose, algorithms were developed that detect active markers on the machine in a stereo image pair, find stereo point correspondences, and estimate the pose of the machine from these. Theoretical influences and accuracies for different systems were estimated with a Monte Carlo simulation, on the basis of which the stereo camera system was designed. Field measurements were used to evaluate the actual achievable accuracies and the robustness of the prototype system. The comparison is present with reference measurements with a laser tracker. The estimated object pose achieved accuracies higher than 16 mm with the translation components and accuracies higher than 3 mrad with the rotation components. As a result, 3D point accuracies higher than 16 mm were achieved by the machine. For the first time, a prototype could be developed that represents an alternative, powerful image-based localization method for machines to the classical geodetic sensors.

2.
Nat Commun ; 13(1): 1868, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35387986

RESUMO

The human parasite Plasmodium malariae has relatives infecting African apes (Plasmodium rodhaini) and New World monkeys (Plasmodium brasilianum), but its origins remain unknown. Using a novel approach to characterise P. malariae-related sequences in wild and captive African apes, we found that this group comprises three distinct lineages, one of which represents a previously unknown, highly divergent species infecting chimpanzees, bonobos and gorillas across central Africa. A second ape-derived lineage is much more closely related to the third, human-infective lineage P. malariae, but exhibits little evidence of genetic exchange with it, and so likely represents a separate species. Moreover, the levels and nature of genetic polymorphisms in P. malariae indicate that it resulted from the zoonotic transmission of an African ape parasite, reminiscent of the origin of P. falciparum. In contrast, P. brasilianum falls within the radiation of human P. malariae, and thus reflects a recent anthroponosis.


Assuntos
Hominidae , Malária Falciparum , Malária , Plasmodium , Animais , Hominidae/genética , Humanos , Malária/parasitologia , Malária/veterinária , Malária Falciparum/parasitologia , Filogenia , Plasmodium/genética , Plasmodium malariae/genética
3.
Ecohealth ; 19(4): 450-457, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36629957

RESUMO

Flies form high-density associations with human settlements and groups of nonhuman primates and are implicated in transmitting pathogens. We investigate the movement of nonhuman primate-associated flies across landscapes surrounding Kibale National Park, Uganda, using a mark-recapture experiment. Flies were marked in nine nonhuman primate groups at the forest edge ([Formula: see text] = 929 flies per group), and we then attempted to recapture them in more anthropized areas (50 m, 200 m and 500 m from where marked; 2-21 days after marking). Flies marked in nonhuman primate groups were recaptured in human areas (19/28,615 recaptured). Metabarcoding of the flies in nonhuman primate groups revealed the DNA of multiple eukaryotic primate parasites. Taken together, these results demonstrate the potential of flies to serve as vectors between nonhuman primates, livestock and humans at this biodiverse interface.


Assuntos
Animais Selvagens , Dípteros , Humanos , Animais , Dípteros/genética , Primatas/parasitologia , Gado , DNA
4.
Nat Commun ; 12(1): 5769, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34599175

RESUMO

Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Δ, Y144Δ, and LLA241/243Δ. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers.


Assuntos
COVID-19/transmissão , COVID-19/virologia , SARS-CoV-2/genética , África Central/epidemiologia , Anticorpos Neutralizantes/imunologia , COVID-19/epidemiologia , Europa (Continente)/epidemiologia , Humanos , Evasão da Resposta Imune/genética , Mutação , Filogenia , Filogeografia , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Viagem/estatística & dados numéricos
5.
Nature ; 598(7882): 652-656, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34646009

RESUMO

Humans are considered as the main host for Mycobacterium leprae1, the aetiological agent of leprosy, but spillover has occurred to other mammals that are now maintenance hosts, such as nine-banded armadillos and red squirrels2,3. Although naturally acquired leprosy has also been described in captive nonhuman primates4-7, the exact origins of infection remain unclear. Here we describe leprosy-like lesions in two wild populations of western chimpanzees (Pan troglodytes verus) in Cantanhez National Park, Guinea-Bissau and Taï National Park, Côte d'Ivoire, West Africa. Longitudinal monitoring of both populations revealed the progression of disease symptoms compatible with advanced leprosy. Screening of faecal and necropsy samples confirmed the presence of M. leprae as the causative agent at each site and phylogenomic comparisons with other strains from humans and other animals show that the chimpanzee strains belong to different and rare genotypes (4N/O and 2F). These findings suggest that M. leprae may be circulating in more wild animals than suspected, either as a result of exposure to humans or other unknown environmental sources.


Assuntos
Hanseníase/veterinária , Pan troglodytes/microbiologia , Animais , Autopsia/veterinária , Côte d'Ivoire , Fezes/microbiologia , Genótipo , Guiné-Bissau , Humanos , Hanseníase/microbiologia , Mycobacterium leprae/genética , Mycobacterium leprae/isolamento & purificação , Filogenia
6.
Microb Genom ; 6(11)2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33125317

RESUMO

Many non-human primate species in sub-Saharan Africa are infected with Treponema pallidum subsp. pertenue, the bacterium causing yaws in humans. In humans, yaws is often characterized by lesions of the extremities and face, while T. pallidum subsp. pallidum causes venereal syphilis and is typically characterized by primary lesions on the genital, anal or oral mucosae. It remains unclear whether other T. pallidum subspecies found in humans also occur in non-human primates and how the genomic diversity of non-human primate T. pallidum subsp. pertenue lineages is distributed across hosts and space. We observed orofacial and genital lesions in sooty mangabeys (Cercocebus atys) in Taï National Park, Côte d'Ivoire and collected swabs and biopsies from symptomatic animals. We also collected non-human primate bones from 8 species in Taï National Park and 16 species from 11 other sites across sub-Saharan Africa. Samples were screened for T. pallidum DNA using polymerase chain reactions (PCRs) and we used in-solution hybridization capture to sequence T. pallidum genomes. We generated three nearly complete T. pallidum genomes from biopsies and swabs and detected treponemal DNA in bones of six non-human primate species in five countries, allowing us to reconstruct three partial genomes. Phylogenomic analyses revealed that both orofacial and genital lesions in sooty mangabeys from Taï National Park were caused by T. pallidum subsp. pertenue. We showed that T. pallidum subsp. pertenue has infected non-human primates in Taï National Park for at least 28 years and has been present in two non-human primate species that had not been described as T. pallidum subsp. pertenue hosts in this ecosystem, western chimpanzees (Pan troglodytes verus) and western red colobus (Piliocolobus badius), complementing clinical evidence that started accumulating in Taï National Park in 2014. More broadly, simian T. pallidum subsp. pertenue strains did not form monophyletic clades based on host species or the symptoms caused, but rather clustered based on geography. Geographical clustering of T. pallidum subsp. pertenue genomes might be compatible with cross-species transmission of T. pallidum subsp. pertenue within ecosystems or environmental exposure, leading to the acquisition of closely related strains. Finally, we found no evidence for mutations that confer antimicrobial resistance.


Assuntos
Cercocebus atys/microbiologia , Genoma Bacteriano/genética , Doenças dos Macacos/transmissão , Treponema/genética , Bouba/veterinária , Animais , Côte d'Ivoire , Sequenciamento de Nucleotídeos em Larga Escala , Doenças dos Macacos/microbiologia , Reação em Cadeia da Polimerase , Treponema/isolamento & purificação , Sequenciamento Completo do Genoma , Bouba/microbiologia , Bouba/transmissão
7.
Science ; 368(6497): 1367-1370, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32554594

RESUMO

Many infectious diseases are thought to have emerged in humans after the Neolithic revolution. Although it is broadly accepted that this also applies to measles, the exact date of emergence for this disease is controversial. We sequenced the genome of a 1912 measles virus and used selection-aware molecular clock modeling to determine the divergence date of measles virus and rinderpest virus. This divergence date represents the earliest possible date for the establishment of measles in human populations. Our analyses show that the measles virus potentially arose as early as the sixth century BCE, possibly coinciding with the rise of large cities.


Assuntos
Doenças Transmissíveis Emergentes/história , Evolução Molecular , Variação Genética , Vírus do Sarampo/genética , Sarampo/história , Cidades/história , Doenças Transmissíveis Emergentes/virologia , História Antiga , Humanos , Sarampo/virologia , Vírus da Peste Bovina/genética
8.
Nat Microbiol ; 5(7): 955-965, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32341480

RESUMO

Monkeypox is a viral zoonotic disease on the rise across endemic habitats. Despite the growing importance of monkeypox virus, our knowledge on its host spectrum and sylvatic maintenance is limited. Here, we describe the recent repeated emergence of monkeypox virus in a wild, human-habituated western chimpanzee (Pan troglodytes verus, hereafter chimpanzee) population from Taï National Park, Ivory Coast. Through daily monitoring, we show that further to causing its typical exanthematous syndrome, monkeypox can present itself as a severe respiratory disease without a diffuse rash. By analysing 949 non-invasively collected samples, we identify the circulation of at least two distinct monkeypox virus lineages and document the shedding of infectious particles in faeces and flies, suggesting that they could mediate indirect transmission. We also show that the carnivorous component of the Taï chimpanzees' diet, mainly consisting of the sympatric monkeys they regularly hunt, did not change nor shift towards rodent consumption (the presumed reservoir) before the outbreaks, suggesting that the sudden emergence of monkeypox virus in this population is probably due to changes in the ecology of the virus itself. Using long-term mortality surveillance data from Taï National Park, we provide evidence of little to no prior viral activity over at least two decades. We conclude that great ape sentinel systems devoted to the longitudinal collection of behavioural and health data can help clarify the epidemiology and clinical presentation of zoonotic pathogens.


Assuntos
Animais Selvagens , Monkeypox virus/fisiologia , Mpox/virologia , Pan troglodytes/virologia , Animais , Ecossistema , Exantema/etiologia , Exantema/metabolismo , Exantema/patologia , Espaço Extracelular/metabolismo , Fezes/virologia , Genoma Viral , Genômica/métodos , Glutationa/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Mpox/complicações , Mpox/metabolismo , Mpox/mortalidade , Monkeypox virus/classificação , Monkeypox virus/isolamento & purificação , Pan troglodytes/metabolismo , Filogenia , Transtornos Respiratórios/etiologia , Transtornos Respiratórios/metabolismo
9.
Mol Ecol Resour ; 20(1): 204-215, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31600853

RESUMO

Despite their ubiquity, in most cases little is known about the impact of eukaryotic parasites on their mammalian hosts. Comparative approaches provide a powerful method to investigate the impact of parasites on host ecology and evolution, though two issues are critical for such efforts: controlling for variation in methods of identifying parasites and incorporating heterogeneity in sampling effort across host species. To address these issues, there is a need for standardized methods to catalogue eukaryotic parasite diversity across broad phylogenetic host ranges. We demonstrate the feasibility of a metabarcoding approach for describing parasite communities by analysing faecal samples from 11 nonhuman primate species representing divergent lineages of the primate phylogeny and the full range of sampling effort (i.e. from no parasites reported in the literature to the best-studied primates). We detected a number of parasite families and regardless of prior sampling effort, metabarcoding of only ten faecal samples identified parasite families previously undescribed in each host (x̅ = 8.5 new families per species). We found more overlap between parasite families detected with metabarcoding and published literature when more research effort-measured as the number of publications-had been conducted on the host species' parasites. More closely related primates and those from the same continent had more similar parasite communities, highlighting the biological relevance of sampling even a small number of hosts. Collectively, results demonstrate that metabarcoding methods are sensitive and powerful enough to standardize studies of eukaryotic parasite communities across host species, providing essential new tools for macroecological studies of parasitism.


Assuntos
Parasitos/isolamento & purificação , Doenças Parasitárias em Animais/parasitologia , Doenças dos Primatas/parasitologia , Primatas/classificação , Primatas/parasitologia , Animais , Fezes/parasitologia , Especificidade de Hospedeiro , Parasitos/classificação , Parasitos/genética , Parasitos/fisiologia , Filogenia
10.
Viruses ; 11(3)2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30893858

RESUMO

New technologies enable viral discovery in a diversity of hosts, providing insights into viral evolution. We used one such approach, the virome capture sequencing for vertebrate viruses (VirCapSeq-VERT) platform, on 21 samples originating from six dead Maxwell's duikers (Philantomba maxwellii) from Taï National Park, Côte d'Ivoire. We detected the presence of an orthohepadnavirus in one animal and characterized its 3128 bp genome. The highest viral copy numbers were detected in the spleen, followed by the lung, blood, and liver, with the lowest copy numbers in the kidney and heart; the virus was not detected in the jejunum. Viral copy numbers in the blood were in the range known from humans with active chronic infections leading to liver histolytic damage, suggesting this virus could be pathogenic in duikers, though many orthohepadnaviruses appear to be apathogenic in other hosts, precluding a formal test of this hypothesis. The virus was not detected in 29 other dead duiker samples from the Côte d'Ivoire and Central African Republic, suggesting either a spillover event or a low prevalence in these populations. Phylogenetic analysis placed the virus as a divergent member of the mammalian clade of orthohepadnaviruses, though its relationship to other orthohepadnaviruses remains uncertain. This represents the first orthohepadnavirus described in an artiodactyl. We have tentatively named this new member of the genus Orthohepadnavirus (family Hepadnaviridae), Taï Forest hepadnavirus. Further studies are needed to determine whether it, or some close relatives, are present in a broader range of artiodactyls, including livestock.


Assuntos
Antílopes/virologia , Orthohepadnavirus/classificação , Orthohepadnavirus/isolamento & purificação , Animais , Côte d'Ivoire , Variação Genética , Genoma Viral , Parques Recreativos , Filogenia
11.
Sportverletz Sportschaden ; 31(4): 222-230, 2017 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-29228408

RESUMO

Background Muscles and tendons are subjected to a high level of stress in everyday life and sports. This often leads to injuries and is associated with training failure and reduced performance as well as with high costs for treatment and rehabilitation. Fast and successful treatment is therefore very important, both from an athletic and economic point of view. This study aims to demonstrate the relevance of biomechanical procedures for the objective monitoring of rehabilitation. At the same time, the results are to be used to establish progress and evaluation criteria for an efficient and controlled rehabilitation. Patients and methods In a retrospective study, a total of 42 patients were evaluated biomechanically after surgical repair of a complete Achilles tendon rupture 18 (18 W) and 26 weeks (26 W) postoperatively. Ground reaction forces in barefoot walking on a treadmill as well as isokinetic maximum strength for the plantar flexors and dorsal extensors were assessed. Results The push-off force on the injured side increased from 0.88 (18 W) to 0.95 (26 W). The percentage of heel contact time on the injured side was 59 % at 18 W and 55 % at 26 W. Plantar flexion torque increased from 70 Nm (18 W) to 90 Nm (26 W) on average on the injured side. The percentage of the plantar flexion deficit (injured/non-injured side) decreased from 34 % to 21 % on the two postoperative measuring dates. Conclusions The described biomechanical methods allow for a quantitative assessment and an objective control of the rehabilitation process. The results can also be used for the definition of evaluation and progression criteria in order to assess the progress of a patient's therapy and to guide the rehabilitation process in a controlled manner.


Assuntos
Tendão do Calcâneo/lesões , Tendão do Calcâneo/cirurgia , Traumatismos dos Tendões/reabilitação , Traumatismos dos Tendões/cirurgia , Adulto , Fenômenos Biomecânicos , Feminino , , Calcanhar , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Torque , Caminhada
12.
Chemistry ; 21(1): 13, 2015 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-25382313

RESUMO

Invited for the cover of this issue is the group of Bernhard Kräutler at the University of Innsbruck, Austria. The image depicts the autumnal "disappearance" of chlorophyll and the ensuing rapid formation of colorless phyllobilins. Read the full text of the article at 10.1002/chem.201404783.


Assuntos
Clorofila/metabolismo , Lilium/química , Tetrapirróis/química , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Clorofila/química , Lilium/metabolismo , Oxirredução , Folhas de Planta/química , Folhas de Planta/metabolismo , Estereoisomerismo
13.
Chemistry ; 21(1): 136-49, 2015 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-25382809

RESUMO

In senescent leaves, chlorophyll typically is broken down to colorless and essentially photo-inactive phyllobilanes, which are linear tetrapyrroles classified as "nonfluorescent" chlorophyll catabolites (NCCs) and dioxobilane-type NCCs (DNCCs). In homogenates of senescent leaves of the tropical evergreen Spathiphyllum wallisii, when left at room temperature and extracted with methanol, the major endogenous, naturally formed NCC was regio- and stereoselectively oxidized (in part) to a mixture of its 15-hydroxy and 15-methoxy derivative. In the absence of methanol in the extract, only the 15-OH-NCC was observed. The endogenous oxidation process depended upon molecular oxygen. It was inhibited by carbon monoxide, as well as by keeping the leaf homogenate and extract at low temperatures. The remarkable "oxidative activity" was inactivated by heating the homogenate for 10 min at 70 °C. Upon addition of a natural epimeric NCC (epiNCC) to the homogenate of senescent or green Sp. wallisii leaves at room temperature, the exogenous epiNCC was oxidized regio- and stereoselectively to 15-OH-epiNCC and 15-OMe-epiNCC. The identical two oxidized epiNCCs were also obtained as products of the oxidation of epiNCC with dicyanodichlorobenzoquinone (DDQ). Water elimination from 15-OH-epiNCC occurred readily and gave a known "yellow" chlorophyll catabolite (YCC). The endogenous oxidation process, described here, may represent the elusive natural path from the colorless NCCs to yellow and pink coloured phyllobilins, which were found in (extracts of) some senescent leaves.


Assuntos
Clorofila/metabolismo , Lilium/química , Tetrapirróis/química , Benzoquinonas/química , Clorofila/química , Cianetos/química , Hidróxidos/química , Lilium/metabolismo , Oxirredução , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Solventes/química , Estereoisomerismo , Temperatura
14.
Environ Sci Pollut Res Int ; 22(19): 14606-20, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25331527

RESUMO

The purpose of the present study was to assess the hazard potentials of contaminated suspended particulate matter (SPM) sampled during a flood event for floodplain soils using in vitro bioassays and chemical analysis. Sediment-contact tests were performed to evaluate the direct exposure of organisms to native soils and SPM at two different trophic levels. For comparison, acetonic extracts were tested using both contact tests and additionally two cell-based biotests for cytotoxicity and Ah receptor-mediated activity (EROD-Assay). The sediment-contact tests were carried out with the dehydrogenase assay with Arthrobacter globiformis and the fish embryo assay with Danio rerio. The results of this study clearly document that native samples may well be significantly more effective than corresponding extracts in the bacteria contact assay or the fish embryo test. These results question the commonly accepted concept that acetonic extracts are likely to overestimate the toxicity of soil and SPM samples. Likewise, the priority organic compounds analyzed failed to fully explain the toxic potential of the samples. The outcomes of this study revealed the insufficient knowledge regarding the relationship between the different exposure pathways. Finally, there is concern about adverse effects by settling suspended particulate matter and remobilized sediments in frequently inundated floodplain soils due to an increase of the hazard potential, if compared with infrequently inundated floodplain soils. We showed that the settling of SPM and sediments revealed a significant impact on the dioxin-like potencies of riparian soils.


Assuntos
Material Particulado/análise , Dibenzodioxinas Policloradas/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Animais , Arthrobacter/efeitos dos fármacos , Bioensaio , Inundações , Sedimentos Geológicos/química , Alemanha , Dose Letal Mediana , Análise Multivariada , Material Particulado/toxicidade , Dibenzodioxinas Policloradas/toxicidade , Rios/química , Solo/química , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/toxicidade , Qualidade da Água , Peixe-Zebra
15.
Chemistry ; 2014 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-25376601

RESUMO

Invited for the cover of this issue is the group of Bernhard Kräutler at the University of Innsbruck, Austria. The image depicts the autumnal "disappearance" of chlorophyll and the ensuing rapid formation of colorless phyllobilins. Read the full text of the article at 10.1002/chem.201404783.

17.
Recent Pat Antiinfect Drug Discov ; 7(3): 223-30, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22742396

RESUMO

The effects of low-temperature plasma treatment on microorganisms typically related to skin diseases are studied qualitatively by the inhibition of growth and viability assays to evaluate the potential for classifying as a prospective antiseptic agent. A variety of microorganisms enveloping gram- negative and gram-positive bacteria as well as one genus of yeast and fungus each were exposed to plasma in vitro. In a comparative approach, two power supplies, both of which produce high voltage pulses yet at different temporal characteristics, are applied for the growth study. While operation with both devices led to growth inhibition of all microbes, the results indicate a superior antimicrobial efficacy for high voltage pulse lengths in the nanosecond scale. Fluorescence assays reveal the efficacy of nanosecond-pulse driven plasma in reducing germ viability. Furthermore, the technical background for patents related to low-temperature plasma technology in the field of plasma medicine is discussed.


Assuntos
Anti-Infecciosos Locais , Antissepsia/instrumentação , Antissepsia/métodos , Gases em Plasma/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Humanos , Testes de Sensibilidade Microbiana/instrumentação , Testes de Sensibilidade Microbiana/métodos , Microsporum/efeitos dos fármacos , Microsporum/fisiologia , Gases em Plasma/uso terapêutico , Estudos Prospectivos , Infecções Cutâneas Estafilocócicas/fisiopatologia , Infecções Cutâneas Estafilocócicas/terapia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia
18.
Emerg Infect Dis ; 18(5): 859-62, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22515991

RESUMO

During 2010-2011, we investigated interspecies transmission of partetraviruses between predators (humans and chimpanzees) and their prey (colobus monkeys) in Côte d'Ivoire. Despite widespread infection in all species investigated, no interspecies transmission could be detected by PCR and genome analysis. All sequences identified formed species- or subspecies (chimpanzee)-specific clusters, which supports a co-evolution hypothesis.


Assuntos
Variação Genética , Infecções por Parvoviridae/transmissão , Parvovirus/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Colobus/virologia , Côte d'Ivoire , DNA Viral/química , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Pan troglodytes/virologia , Infecções por Parvoviridae/virologia , Parvovirus/classificação , Filogenia , Análise de Sequência de DNA , Proteínas Virais/genética , Adulto Jovem
19.
IEEE Trans Pattern Anal Mach Intell ; 34(10): 1902-14, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22201058

RESUMO

This paper describes an approach for recognizing instances of a 3D object in a single camera image and for determining their 3D poses. A hierarchical model is generated solely based on the geometry information of a 3D CAD model of the object. The approach does not rely on texture or reflectance information of the object's surface, making it useful for a wide range of industrial and robotic applications, e.g., bin-picking. A hierarchical view-based approach that addresses typical problems of previous methods is applied: It handles true perspective, is robust to noise, occlusions, and clutter to an extent that is sufficient for many practical applications, and is invariant to contrast changes. For the generation of this hierarchical model, a new model image generation technique by which scale-space effects can be taken into account is presented. The necessary object views are derived using a similarity-based aspect graph. The high robustness of an exhaustive search is combined with an efficient hierarchical search. The 3D pose is refined by using a least-squares adjustment that minimizes geometric distances in the image, yielding a position accuracy of up to 0.12 percent with respect to the object distance, and an orientation accuracy of up to 0.35 degree in our tests. The recognition time is largely independent of the complexity of the object, but depends mainly on the range of poses within which the object may appear in front of the camera. For efficiency reasons, the approach allows the restriction of the pose range depending on the application. Typical runtimes are in the range of a few hundred ms.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...