RESUMO
Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.
Assuntos
Syzygium , Árvores , Especiação Genética , Genômica , Filogenia , Syzygium/genéticaRESUMO
A newly fabricated prosthesis may need a complete remake if it does not match the patient's skin tone. Remakes of craniofacial implant-retained prostheses may require significant time and incur additional costs. An alternative procedure is presented to improve the predictability of such prostheses.
Assuntos
Prótese Maxilofacial , Pigmentação em Prótese/métodos , Resinas Acrílicas , Humanos , Implante de Prótese Maxilofacial/instrumentação , Elastômeros de SiliconeRESUMO
BACKGROUND AND AIMS: Recent studies have reported high prevalence rates of short segments of specialized columnar epithelium (SCE) in the distal esophagus. The association of SCE with gastroesophageal reflux disease is not well established. We studied the prevalence and associations of short segments of SCE in the distal esophagus amongst Indians. METHODS: 271 patients (mean age 36 [14] y; 160 men) undergoing diagnostic upper gastrointestinal endoscopy were interviewed regarding symptoms of gastroesophageal reflux, and history of medications, smoking or chewing tobacco and alcohol ingestion. At endoscopy, presence and grade of esophagitis and hiatus hernia were recorded. One biopsy each was taken from the squamocolumnar junction and 2 cm proximal to it. Biopsies were stained with hematoxylin/eosin and alcian blue/periodic acid-Schiff. The pathologist was blinded to the clinical and endoscopic data. RESULTS: Short segments of SCE in the distal esophagus were present in 16/271 (6%; CI 5.03-6.97) patients. Increasing age (p<0.01), and endoscopic (p<0.01) and histologic (p<0.001) esophagitis were associated with its presence, whereas symptoms of gastroesophageal reflux, smoking, tobacco chewing, use of alcohol or non-steroidal anti-inflammatory drugs, and hiatus hernia were not. One patient with SCE had dysplasia. CONCLUSION: Prevalence of short segments of SCE in the distal esophagus amongst Indians is low and is usually associated with inflammation in the esophagus.
Assuntos
Esôfago/química , Esôfago/patologia , Mucosa Laríngea/patologia , Adulto , Idoso , Azul Alciano , Esôfago de Barrett/etiologia , Intervalos de Confiança , Endoscopia , Feminino , Refluxo Gastroesofágico/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Reação do Ácido Periódico de Schiff/métodos , PrevalênciaRESUMO
Centring of spectacle lenses is much neglected field of ophthalmology. The prismatic effect caused by wrong centring results in a phoria on the eye muscles which in turn causes persistent eyestrain. The theory of visual axis, optical axis and angle alpha is discussed. Using new methods the visual axis and optical axis of 35 subjects were measured. The results were computed for facial asymmetry, parallax error, angle alpha and also decentration for near vision. The results show that decentration is required on account of each of these factors. Considerable correction is needed in the vertical direction, a fact much neglected nowadays; and vertical decentration results in vertical phoria which is more symptomatic than horizontal phorias. Angle Alpha was computed for each of these patients. A new devise called 'The Kerala Decentration Meter' using the pinhole method for measuring the degree of decentration from the datum centre of the frame, and capable of correcting all the factors described above, is shown with diagrams.