Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Clin Ophthalmol ; 17: 3379-3387, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37954910

RESUMEN

Purpose: To report on the visual outcomes of the second-generation (ActivShieldTM) Light Adjustable Lens (LAL) used in cataract surgery for patients with a history of laser refractive surgery (LASIK and/or photorefractive keratectomy [PRK]) using a co-managed, open-access methodology. Patients and Methods: This retrospective case series of consecutive patients with history of laser refractive surgery implanted with the second-generation LAL with an emmetropic target were included in the study. Following surgery, all patients received their ultraviolet (UV) light treatments at a separate open-access facility through a co-managed arrangement. Uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and residual cylinder for eyes with an emmetropic refractive target were the primary outcome measures as documented at the patient's final, stable, refractive postoperative exam. Results: Thirty-three patients (34 eyes) with a history of laser refractive surgery were included in the study and implanted with the second-generation LAL with a postoperative emmetropic refractive target. Twenty-eight (82.4%) saw 20/20 or better and 9 (26.5%) saw 20/15 or better. The mean SE was 0.01 ± 0.31 D and 33 (97.1%) were within ±0.50 D SE of plano. The mean residual cylinder was -0.28 ± 0.32 D and 30 (88.2%) were within ±0.50 D. Conclusion: Use of the second-generation LAL was efficacious in cataract surgical patients with a history of LASIK and/or PRK using a co-managed, open-access methodology.

2.
IEEE Trans Vis Comput Graph ; 28(4): 1835-1847, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33001803

RESUMEN

We propose a robust normal estimation method for both point clouds and meshes using a low rank matrix approximation algorithm. First, we compute a local isotropic structure for each point and find its similar, non-local structures that we organize into a matrix. We then show that a low rank matrix approximation algorithm can robustly estimate normals for both point clouds and meshes. Furthermore, we provide a new filtering method for point cloud data to smooth the position data to fit the estimated normals. We show the applications of our method to point cloud filtering, point set upsampling, surface reconstruction, mesh denoising, and geometric texture removal. Our experiments show that our method generally achieves better results than existing methods.

4.
Water Environ Res ; 93(4): 502-515, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32866312

RESUMEN

While researchers have acknowledged the potential role of environmental scientists, engineers, and industrial hygienists during this pandemic, the role of the water utility professional is often overlooked. The wastewater sector is critical to public health protection and employs collection and treatment system workers who perform tasks with high potential for exposures to biological agents. While various technical guidances and reports have initially provided direction to the water sector, the rapidly growing body of research publications necessitates the constant review of these papers and data synthesis. This paper presents the latest findings and highlights their implications from a water and wastewater utility operation and management perspective. PRACTITIONER POINTS: Extrapolation from SARS-CoV-1 and MERS-CoV, as well as other surrogates, has helped predicting SARS-CoV-2 behavior and risk management. Data from treated wastewater effluent suggest that current processes are sufficient for SARS-CoV-2 control. Scientific evidence supports the possibility of fecal-oral transmission for SARS-CoV-2. Limited evidence supports the potential survival of infective SARS-CoV-2 on surfaces and in aerosols and the efficacy of control measures at reducing transmission. Protective practices and PPE can protect workers from SARS-CoV-2 and other pathogens found in wastewater.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Pandemias , Aguas Residuales , Agua
5.
IEEE Trans Vis Comput Graph ; 24(7): 2129-2139, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-28600251

RESUMEN

Retrieving salient structure from textured images is an important but difficult problem in computer vision because texture, which can be irregular, anisotropic, non-uniform and complex, shares many of the same properties as structure. Observing that salient structure in a textured image should be piece-wise smooth, we present a method to retrieve such structures using an minimization of a modified form of the relative total variation metric. Thanks to the characteristics shared by texture and small structures, our method is effective at retrieving structure based on scale as well. Our method outperforms state-of-art methods in texture removal as well as scale-space filtering. We also demonstrate our method's ability in other applications such as edge detection, clip art compression artifact removal, and inverse half-toning.

6.
PLoS One ; 10(6): e0127162, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26039066

RESUMEN

Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks. Regardless of its actual identification, this new specimen provides further evidence that large-bodied lamniform sharks had evolved prior to the Late Cretaceous.


Asunto(s)
Tamaño Corporal , Fósiles , Tiburones/anatomía & histología , Tiburones/clasificación , Animales , Texas
7.
Mol Phylogenet Evol ; 52(2): 416-23, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19254770

RESUMEN

Phylogenetic relationships among the trichomycterid catfishes are investigated for the first time using molecular sequence data. Data derived from mitochondrial and nuclear DNA sequences for representatives of 17 genera were analyzed to test previous hypotheses of relationships among trichomycterid subfamilies, the monophyly of the subfamily Stegophilinae, and the monophyly and relationships among the genera of parasitic members of the family. We analyzed 2325 aligned base-pairs from mitochondrial 12S, 16S, ND4 (tRNA(His) tRNA(Ser)), and the nuclear histone H3 gene for representatives of 10 of 12 stegophiline and 3 of 4 vandelliine genera, plus 10 outgroup taxa selected to represent the range of subfamilial diversity. Maximum parsimony and likelihood approaches resolved a monophyletic semiparasitic Stegophilinae as the sister-group of the obligate hematophagous Vandelliinae. At the level of subfamilies, the pattern of relationships of the parasitic members among the remainder of the family is fully congruent with the most recent hypothesis of relationships for trichomycterids based exclusively on morphological data. Within stegophilines, our results differ from multiple previous morphological studies in recovery of (1) Haemomaster and Ochmacanthus as sister-taxa, (2) the morphologically plesiomorphic Pareidon microps nested within a relatively distal part of the tree topology, (3) Apomatoceros as sister to Henonemus, rather than to the morphologically similar Megalocentor. These result indicate that parasitism arose once and was unreversed within the Trichomycteridae. Survey of diet and feeding morphology among trichomycterids suggests that the semiparasitic lifestyle of the members of the Stegophilinae was retained in the enigmatic Pareiodon microps, despite reversal to the generalized trichomycterid condition of the associated morphological specializations found in all other stegophilines. These results further support the reconstruction of semiparasitism, rather than blood feeding, for the shared common ancestor of the parasitic Trichomycteridae.


Asunto(s)
Bagres/genética , Evolución Molecular , Filogenia , Animales , Bagres/anatomía & histología , Bagres/clasificación , Bagres/parasitología , Núcleo Celular/genética , ADN Mitocondrial/genética , Funciones de Verosimilitud , Modelos Genéticos , Alineación de Secuencia , Análisis de Secuencia de ADN
8.
Water Environ Res ; 80(2): 101-8, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18330219

RESUMEN

Anaerobic digestion of corn ethanol thin stillage was tested at thermophilic temperature (55 degrees C) with two completely stirred tank reactors. The thin stillage wastestream was organically concentrated with 100 g/L total chemical oxygen demand and 60 g/L volatiles solids and a low pH of approximately 4.0. Steady-state was achieved at 30-, 20-, and 15-day hydraulic retention times (HRTs) and digester failure at a 12-day HRT. Significant reduction of volatile solids was achieved, with a maximum reduction (89.8%) at the 20-day HRT. Methane yield ranged from 0.6 to 0.7 L methane/g volatile solids removed during steady-state operation. Effluent volatile fatty acids below 200 mg/L as acetic acid were achieved at 20- and 30-day HRTs. Ultrasonic pretreatment was used for one digester, although no significant improvement was observed. Ethanol plant natural gas consumption could be reduced 43 to 59% with the methane produced, while saving an estimated $7 to $17 million ($10 million likely) for a facility producing 360 million L ethanol/y.


Asunto(s)
Reactores Biológicos , Digestión , Contaminación Ambiental/prevención & control , Etanol/metabolismo , Ácidos Grasos Volátiles/metabolismo , Metano/metabolismo , Anaerobiosis , Biodegradación Ambiental , Concentración de Iones de Hidrógeno , Temperatura , Factores de Tiempo , Ultrasonido , Zea mays
9.
IEEE Trans Vis Comput Graph ; 13(3): 610-9, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17356225

RESUMEN

Dual Contouring (DC) is a feature-preserving isosurfacing method that extracts crack-free surfaces from both uniform and adaptive octree grids. We present an extension of DC that further guarantees that the mesh generated is a manifold even under adaptive simplification. Our main contribution is an octree-based topology-preserving vertex-clustering algorithm for adaptive contouring. The contoured surface generated by our method contains only manifold vertices and edges, preserves sharp features, and possesses much better adaptivity than those generated by other isosurfacing methods under topologically safe simplification.

10.
Planta ; 222(5): 858-66, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16047198

RESUMEN

Genes coding for an iris ribosomal-inactivating protein (I-RIP), a maize beta-glucanase (M-GLU), and a Mirabilis jalapa antimicrobial peptide (Mj-AMP1) were separately introduced into tomato (Lycopersicon esculentum cv. Sweet Chelsea) cotyledons via Agrobacterium tumefaciens-mediated transformation. Transgenic lines carrying each of the transgenes were confirmed for integration into the tomato genome using Southern blot hybridization. Transcription of I-RIP, M-GLU, and Mj-AMP1 genes in various transgenic lines was determined using Northern blot analysis. Plants of selected transgenic lines were inoculated with a 2-3x10(4) conidial spores/ml suspension of the fungal pathogen Alternaria solani, the causal agent of tomato early blight. Compared to control (non-transformed) plants, two transgenic lines carrying either a M-GLU or Mj-AMP1 showed enhanced resistance to early blight disease. None of the four lines carrying the I-RIP transgene showed increased resistance to early blight.


Asunto(s)
Genes de Plantas , Enfermedades de las Plantas/genética , Solanum lycopersicum/genética , Agrobacterium tumefaciens/genética , Alternaria/patogenicidad , Expresión Génica , Glicósido Hidrolasas/genética , Género Iris/genética , Solanum lycopersicum/microbiología , Mirabilis/genética , N-Glicosil Hidrolasas/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Proteínas Inactivadoras de Ribosomas Tipo 1 , Transformación Genética , Zea mays/enzimología , Zea mays/genética
11.
Mol Phylogenet Evol ; 36(1): 135-53, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15904862

RESUMEN

Suprafamilial relationships among characiform fishes and implications for the taxonomy and biogeographic history of the Characiformes were investigated by parsimony analysis of four nuclear and two mitochondrial genes across 124 ingroup and 11 outgroup taxa. Simultaneous analysis of 3660 aligned base pairs from the mitochondrial 16S and cytochrome b genes and the nuclear recombination activating gene (RAG2), seven in absentia (sia), forkhead (fkh), and alpha-tropomyosin (trop) gene loci confirmed the non-monophyly of the African and Neotropical assemblages and corroborated many suprafamilial groups proposed previously on the basis of morphological features. The African distichodontids plus citharinids were strongly supported as a monophyletic Citharinoidei that is the sistergroup to all other characiforms, which form a monophyletic Characoidei composed of two large clades. The first represents an assemblage of both African and Neotropical taxa, wherein a monophyletic African Alestidae is sister to a smaller clade comprised of the Neotropical families Ctenolucidae, Lebiasinidae, and the African Hepsetidae, with that assemblage sister to a strictly Neotropical clade comprised of the Crenuchidae and Erythrinidae. The second clade within the Characoidei is strictly Neotropical and includes all other Characiformes grouped into two well supported major clades. The first, corresponding to a traditional definition of the Characidae, is congruent with some groupings previously supported by morphological evidence. The second clade comprises a monophyletic Anostomoidea that is sister to a clade formed by the families Hemiodontidae, Parodontidae, and Serrasalmidae, with that assemblage, in turn, the sistergroup of the Cynodontidae. Serrasalmidae, traditionally regarded as a subfamily of Characidae, was recovered as the sistergroup of (Anostomoidea (Parodontidae+Hemiodontidae)) and the family Cynodontidae was recovered with strong support as the sistergroup to this assemblage. Our results reveal three instances of trans-continental sistergroup relationships and, in light of the fossil evidence, suggest that marine dispersal cannot be ruled out a priori and that a simple model of vicariance does not readily explain the biogeographic history of the characiform fishes.


Asunto(s)
Peces/clasificación , Peces/genética , Animales , Secuencia de Bases , Citocromos b/genética , ADN/genética , Evolución Molecular , Proteínas de Peces/genética , Factores de Transcripción Forkhead , Proteínas Nucleares/genética , Filogenia , ARN Ribosómico 16S/genética , Factores de Transcripción/genética , Tropomiosina/genética , Ubiquitina-Proteína Ligasas
13.
J Morphol ; 254(2): 139-48, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12353298

RESUMEN

Two types of odontodes, or dermal teeth, occur in the neotropical Andean astroblepid catfishes. Both odontode types conform in structure to dermal teeth of gnathostomes in having dentine surrounding a central pulp cavity covered by a superficial layer of enameloid, but differ from one another in terms of attachment and association with other epidermis features. Type I odontodes in astroblepids, also found in all representatives of the superfamily Loricarioidea, are larger (40-50 microm base diameter), generally conical and sharply pointed, occur on the fin rays, and are associated with dermal bone. Type I odontodes attach to an elevated pediment of dermal bone of the fin lepidotrich, and to dermal bone generally in loricarioids, via a ring of connective tissue. Type II odontodes of astroblepids are smaller (15-20 microm base diameter) and blunt, occur in the skin of the head, maxillary barbels, nasal flap, and lip margins, and are not associated with dermal bone. Observations based on histology and scanning electron microscopy indicate that Type II odontodes are associated with other epithelial structures to form a putative mechanosensory organ. The odontode base lies deep in the dermis. The shaft is surrounded by a dense patch of microvillous epithelium and projects from within a pit formed by an elevated ring of laminar epithelial cells bearing several columnar, knob-like putative mechanosensory structures. Type II odontode organs have thus far been observed in only three astroblepid species, Astroblepus longifilis, A. chotae, A. rosei, where they occur in especially dense arrays on the maxillary barbels, surrounded by discrete patches of microvilli and separate mechanoreceptors. Type II odontode organs are less dense elsewhere on the body, but also occur in the skin of the snout, head, and lips. Typical taste buds are absent from the barbels of these species, but present in other astroblepids. The presence of Type II odontodes and their association with specialized epithelial pit organs are unique to astroblepids among siluriforms and may be potentially important adaptations to life in torrential mountain streams.


Asunto(s)
Bagres/anatomía & histología , Piel/anatomía & histología , Diente/anatomía & histología , Animales , Microscopía Electrónica de Rastreo , Odontogénesis
14.
Evolution ; 50(4): 1661-1675, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28565701

RESUMEN

The "decoupling hypothesis" has been proposed as a mechanistic basis for the evolution of novel structure and function. Decoupling derives from the release of functional constraints via loss of linkages and/or repetition of individual elements as redundant design components, followed by specialization of one or more elements. Examples of apomorphic decoupling have been suggested for several groups of organisms, however there have been few empirical tests of explicit statements concerning functional and morphological consequences of decoupling. Using the loricarioid catfishes, we tested one particular consequence of decoupling, the prediction that clades possessing decoupled systems having increased biomechanical complexity will exhibit greater morphological variability of associated structures than outgroups having no such decoupled systems. Morphometric procedures based on interlandmark distances were used to quantify morphological variance at three levels of design at successive nodes in the loricarioid cladogram. Additional landmark-based procedures were used to localize major patterns of shape change between clades. We report significantly greater within-group morphometric variance at all three morphological levels in those lineages associated with decoupling events, confirming our predictions under the decoupling hypothesis. Two of 12 comparisons, however, yielded significant variance effects where none were predicted. Localization of the major patterns of shape change suggests that disassociation between morphological and functional evolution may contribute to the lack of fit between variance predictions and decoupling in these two comparisons.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...