12,358 research outputs found
Taxonomic results of the Bryotrop expedition to Zaire and Rwanda : 24., Leskeaceae, Brachytheciaceae, Stereophyllaceae, Plagiotheciaceae, Entodontaceae, Sematophyllaceae p.pte, Hypnaceae (except Hypnum)
This very distinctive and easily recognized moss has terete foliation when dry, and has leaves spreading when moist. The leaves are ovate, abruptly broad-acuminate, about 1.5-2 mm long, and strongly plicate. The single costa extends to the base of the acumen, and the laminal cells are 1-2(-3):1 and low unipapillose
Biogeography of the Greater Antillean mosses
The distinctions between dispersal and vicariance are discussed and shown how they relate to geological history. Postulated theories on the tectonic origins and history of the Greater Antilles are reviewed, as well as possible climatic events that would affect biogeography. Numerous zoological examples are presented to argue both dispersalist and vicariance viewpoints. It is proposed that the modern moss flora of the Greater Antilles is best explained primarily by dispersal events. Post-vicariant events, such as Pleistocene climate changes, would have extirpated the vast majority of mosses from the islands and even among those taxa that survived, disperal by the same taxa would have obscured their origins. It is assumed that many of the North American elements in the high elevations of Hispaniola are a result of invasions during the Pleistocene. The Andean elements are considered relatively recent dispersally derived taxa that have successfully colonized the Antilles because of ecologically compatible habitats
Unit circle MVDR beamformer
The array polynomial is the z-transform of the array weights for a narrowband
planewave beamformer using a uniform linear array (ULA). Evaluating the array
polynomial on the unit circle in the complex plane yields the beampattern. The
locations of the polynomial zeros on the unit circle indicate the nulls of the
beampattern. For planewave signals measured with a ULA, the locations of the
ensemble MVDR polynomial zeros are constrained on the unit circle. However,
sample matrix inversion (SMI) MVDR polynomial zeros generally do not fall on
the unit circle. The proposed unit circle MVDR (UC MVDR) projects the zeros of
the SMI MVDR polynomial radially on the unit circle. This satisfies the
constraint on the zeros of ensemble MVDR polynomial. Numerical simulations show
that the UC MVDR beamformer suppresses interferers better than the SMI MVDR and
the diagonal loaded MVDR beamformer and also improves the white noise gain
(WNG).Comment: Accepted to ICASSP 201
On the variation of leaf border in Rhizomnium (Cinclidiaceae)
In the genus Rhizomnium T. Kop. most taxa have a strong leaf border several cells broad and bi- to tristratose. Rhizomnium striatulum (Mitt.) T. Kop. belongs to that group. In Northeast China one population of R. striatulum was found with a very weak leaf border, and also the costa of these plants is weaker than is characteristic for the species. The deviating population is figured and its significance discussed. The distribution of R. striatulum is mapped
Fundamental Studies Connected with Electrochemical Energy Storage
Papers are presented which deal with electrochemical research activities. Emphasis is placed on electrochemical energy storage devices. Topics discussed include: adsorption of dendrite inhibitors on zinc; proton discharge process; electron and protron transfer; quantum mechanical formulation of electron transfer rates; and theory of electrochemical kinetics in terms of two models of activation; thermal and electrostatic
Bryophytes of Uganda : 5., Bryocrumia L.E.Anderson (Hypnaceae) ; a monotypic moss genus new to Africa
A number of collections from Africa identified as Phyllodon scutellifolius or Glossadelphus serpyllifolius belong to Bryocrumia vivicolor, previously known only from America and Asia. Phyllodon scutellifolius is known only from one (possibly two) collections from Madagascar, and Glossadelphus serpyllifolius is a synonym of Bryocrumia vivicolor
Plagiothecium lucidum (Hook. f. & Wils.) Paris in tropical Africa
Plagiothecium lucidum (Hook. f. & Wils.) Paris is confirmed as a new addition to the bryoflora of tropical Africa on the basis of two collections from the Bale Mountains in Ethiopia. The type material of Isopterygium integrifolium Bartr. from Costa Rica in Central America is evaluated and this species is considered to be conspecific with P. lucidum. As a result of this taxonomic conclusion the range of this species is extended to Costa Rica and this is the first recognition of this species in the Central American isthmus. A world distribution map for this species is presented and some details of African plants and the type of I. integrifolium are illustrated
Bryophytes from the Republic of Equatorial Guinea (West-Central Africa) : 2., bryophytes collected by Emilio Guinea (1907-1985) in the Island of Bioco in 1947
Some unidentified samples of bryophytes collected by Emilio Guinea in Bioco (Equatorial Guinea) in 1947 have been studied. Twenty-seven taxa are the result of this study, nine of them being new for Equatorial Guinea and two new for the island of Bioco.Se han estudiado varias muestras de briófitos sin identificar recogidas por Emilio Guinea en Bioco (Guinea Ecuatorial) en 1947. Veintisiete taxones son el resultado de este estudio, siendo nueve de ellos novedad para Guinea Ecuatorial y dos más, nuevos para la isla de Bioco
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