Germination patterns and ecological characteristics of Vellozia seeds from high-altitude sites in south-eastern Brazil

2013 ◽  
Vol 23 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Letícia A. Soares da Mota ◽  
Queila S. Garcia
Keyword(s):  
Light Sensitivity ◽  
Mountain Range ◽  
Continuous Darkness ◽  
South Eastern ◽  
Eastern Brazil ◽  
Germination Characteristics ◽  
Wide Range ◽  
Minas Gerais State ◽  
High Degree ◽  
Seed Characteristics

AbstractThe present work aims to determine whether there are patterns of seed and germination characteristics in Vellozia due to the phylogenetic proximity among the species examined and if these characteristics explain their restricted geographical distributions. We evaluated the germination characteristics of freshly collected seeds from 13 species of the genus Vellozia (Velloziaceae) that show different degrees of endemism, collected at various locations in the Espinhaço Mountain Range in Minas Gerais State, south-eastern Brazil. The size and mass of the seeds, as well as the influence of light and temperature on their germination, were measured. Experiments were performed in germination chambers under constant temperatures of 10–40°C (intervals of 5°C), with a 12-h photoperiod, as well as in continuous darkness. All species studied had small seeds with mass varying from 0.06 to 1.21 mg. Most species required light for germination, displaying high germinability in the range of 15–40°C; some species, however, germinated in the absence of light at the highest temperatures (35 and 40°C). The sizes and masses of the seeds showed significant linear correlations, but light sensitivity was not related to these seed characteristics. The responses observed suggest that light requirement for germination, associated with the small sizes of Vellozia spp. seeds, contribute to the formation of persistent seed banks. The observed tolerance of these seeds to a wide range of germination temperatures is consistent with the large daily temperature fluctuations experienced in campos rupestres sites, although these seed characteristics cannot by themselves explain the high degree of endemism or the restricted distributions observed among the species examined.

Germination characteristics of Syngonanthusseeds (Eriocaulaceae) incampos rupestresvegetation in south-eastern Brazil

2010 ◽  
Vol 21 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Patrícia G. Oliveira ◽  
Queila S. Garcia
Keyword(s):  
Geographic Distribution ◽  
Campos Rupestres ◽  
Continuous Darkness ◽  
Eastern Brazil ◽  
Light Requirements ◽  
Germination Characteristics ◽  
Minas Gerais State ◽  
Water Conditions ◽  
Different Temperatures ◽  
Soil Water Conditions

AbstractThe present study evaluated the size and germination characteristics of seeds of seven species ofSyngonanthus(distributed among four sections) that occur in different microhabitats incampos rupestresvegetation in Minas Gerais State, to determine if (1) the germination responses of the various species characterize a single germination pattern for the genus; and (2) there is a correlation between the germination characteristics and the geographic distribution as well as the microhabitat of the different species. The experiments were undertaken with recently collected seeds exposed to a 12-h photoperiod and continuous darkness, at constant temperatures of 10–40°C (at intervals of 5°C) in germination chambers. The results indicated the existence of a pattern of reduced seed size and light requirements for germination within the genus. The geographic distribution of different species of the genus cannot be explained by the responses of seed germination to different temperatures, but suggests some relationship to their edaphic microhabitats. Therefore, germination characteristics of the populations studied may have been selected to colonize specific environments at different soil water conditions.

scholarly journals MINERAIS RECENTEMENTE DESCRITOS NO BRASIL: A PARTICIPAÇÃO DO CENTRO DE PESQUISA PROF. MANOEL TEIXEIRA DA COSTA - CPMTC, INSTITUTO DE GEOCIÊNCIAS (UFMG)

2018 ◽  
Author(s):  
Mario Luiz de Sá Carneiro Chaves ◽  
Antônio Wilson Romano ◽  
Luiz Alberto Dias Menezes Filho
Keyword(s):  
Minas Gerais ◽  
New Mineral ◽  
Mountain Range ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
New Mineral Species ◽  
Eastern Brazil ◽  
Minas Gerais State ◽  
Mining Projects ◽  
Phd Thesis

Embora o potencial mineral do Brasil seja imenso e, por conseguinte, a possibilidade de encontro de novas espécies minerais nos empreendimentos minerários seja naturalmente alta, até 2010 somente 51 descobertas haviam sido verificadas no país. Entretanto, nos últimos sete anos, através de um projeto de Tese de Doutoramento realizado no Programa de Pós-Graduação em Geologia do IGC/UFMG, esta situação procurou ser mudada. Com ênfase em dois dos principais ambientes geológicos do Estado de Minas Gerais e adjacências, a Província Pegmatítica Oriental do Brasil e a Serra do Espinhaço, estudos foram conduzidos visando especificamente o encontro de novos minerais. Destacam-se os resultados extremamenete satisfatórios; nesses anos foram descobertos oito minerais, o que representa média de 1,3 mineral/ano, contrastando com os inexpressivos 0,2 mineral/ano verificados desde 1789 (ano em que o crisoberilo foi descrito). Os novos minerais são, incluindo seus códigos de identificação na International Mineralogical Association (IMA): carlosbarbosaíta [(UO2)2Nb2O6(OH)2.2H2O], IMA 2010-047; pauloabibita [NaNbO3], IMA 2012-090; cesarferreiraíta [Fe2+Fe3+2(AsO4)2(OH)2.8H2O], IMA 2012-099; correianevesita [Fe2+Mn2+2(PO4)2.3H2O], IMA 2013-007; almeidaíta [Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2], IMA 2013-020; wilancookita [(Ba,K,Na)8(Ba,Li,[])6Be24P24O96.3H2O], IMA 2015-034; parisita-(La) [CaLa2(CO3)3F2], IMA 2016-031; e brandãoita [BeAl2(PO4)2(OH)2(H2O)4], IMA 2016-071a. Este foi o primeiro programa de pesquisa desenvolvido no país voltado especialmente para a descoberta de novos minerais, tendo alcançado pleno êxito.Palavras Chave: Novos minerais, Centro de Pesquisa Prof. Manoel Teixeira da Costa, (IGC-UFMG), BrasilAbstract:RECENT MINERALS DESCRIBED IN BRAZIL: PARTICIPATION OF THE CENTRO DE PESQUISA PROF. MANOEL TEIXEIRA DA COSTA - CPMTC, GEOSCIENCES INSTITUTE (UFMG). Although the mineral potential of Brazil is immense and, consequently, the possibility of finding new mineral species in mining projects is obviously high, until 2010 only 51 discoveries had been verified in this country. However, in the last seven years, through a PhD Thesis project carried at the Postgraduate in Geology Program of the IGC/UFMG, this situation has been modified. With emphasis on two of the main geological environments of Minas Gerais State and surrounding regions, the Eastern Brazil Pegmatite Province and the Espinhaço Mountain Range, studies were conducted specifically aimed at finding new minerals. The results are extremely satisfactory; in those years eight minerals were discovered, representing an average of 1.3 mineral/year, contrasting with the inexpressive 0.2 mineral/year verified since 1789 (year of chrysoberyl description). The new minerals are, including their identification codes in the International Mineralogical Association (IMA): carlosbarbosaite [(UO2)2Nb2O6(OH)2.2H2O], IMA 2010-047; pauloabibite [NaNbO3], IMA 2012-090; cesarferreiraita [Fe2+Fe3+2(AsO4)2(OH)2.8H2O], IMA 2012-099; correianevesite [Fe2+Mn2+2(PO4)2.3H2O], IMA 2013-007; almeidaite [Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2], IMA 2013-020; wilancookite [(Ba,K,Na)8(Ba,Li,[])6Be24P24O96.3H2O], IMA 2015-034; parisite-(La) [CaLa2(CO3)3F2], IMA 2016-031; and brandãoite [BeAl2(PO4)2(OH)2(H2O)4], IMA 2016-071a. This was the first research program developed in the country focused especially on the discovery of new minerals, reaching full success.Keywords: New minerals, Prof. Manoel Teixeira da Costa Research Center (IGC-UFMG), Brazil. 

scholarly journals Infection patterns of Paradollfusnema amphisbaenia (Nematoda: Cosmocercidae) in a population of Amphisbaena wuchereri (Squamata: Amphisbaenidae) from Minas Gerais state, south-eastern Brazil, and its relations with host size, sex and fat body mass

2012 ◽  
Vol 87 (2) ◽  
pp. 135-140 ◽  
Author(s):  
R. Filogonio ◽  
G.M. Toledo ◽  
L.A. Anjos ◽  
B. Rajão ◽  
C.A.B. Galdino ◽  
...  
Keyword(s):  
Small Intestine ◽  
Body Mass ◽  
Fat Body ◽  
Nematode Species ◽  
Minas Gerais ◽  
Gastrointestinal Parasites ◽  
South Eastern ◽  
Eastern Brazil ◽  
Minas Gerais State ◽  
Fat Body Mass

AbstractSpecimens (n= 41) of the amphisbaenid Amphisbaena wuchereri taken from a population in Minas Gerais state, south-eastern Brazil, were examined for gastrointestinal parasites. A single nematode species was found, Paradollfusnema amphisbaenia. This was a new host record for this nematode species. This parasite was encountered in the large intestine (prevalence of 100%), in the stomach (prevalence of 2%) and in the small intestine (prevalence of 7.3%). The intensity of infection ranged from 1 to 457 individual parasites per host and was positively correlated with body size of both male and female amphisbaenians. The discrepancy index (D) indicated that P. amphisbaenia tended to an even distribution in this host population. The nematode, which did not affect fat body mass, induced inflammatory infiltrations in the small intestine, indicating that the parasites might injure the host's organs.

scholarly journals Characterization of non-calcareous "thin" red clay from south-eastern Brazil: applicability in wall tile manufacture

Cerâmica ◽  
2012 ◽  
Vol 58 (345) ◽  
pp. 29-35 ◽  
Author(s):  
S. J. G. Sousa ◽  
J. N. F. Holanda
Keyword(s):  
Wall Tile ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Firing Cycle ◽  
Red Clay ◽  
X Ray ◽  
Dry Process ◽  
South Eastern ◽  
Eastern Brazil ◽  
Wide Range

In this work the use of "thin" red clay from south-eastern Brazil (Campos dos Goytacazes, RJ) as raw material for the manufacture of wall tile was investigated. A wide range of characterization techniques was employed, including X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), grain-size analysis, and thermogravimetric analysis. The wall tile body was prepared by the dry process. The tile pieces were uniaxially pressed and fired between 1080 - 1180 ºC using a fast-firing cycle. The following technological properties were determined: linear shrinkage, water absorption, apparent density, and flexural strength. The development of the microstructure was followed by SEM and XRD analyses. It was found that the "thin" red clay is kaolinitic type containing a substantial amount of quartz. The results also showed that the "thin" red clay could be used in the manufacture of wall tiles, as they present properties compatible with those specified for class BIII of ISO 13006 standard.

Understanding Conformational Entropy in Small Molecules

2020 ◽  
Author(s):  
Lucian Chan ◽  
Garrett Morris ◽  
Geoffrey Hutchison
Keyword(s):  
Small Molecules ◽  
Degrees Of Freedom ◽  
Absolute Error ◽  
Low Energy ◽  
Standard Entropy ◽  
Free Energies ◽  
Conformational Entropy ◽  
Wide Range ◽  
High Degree ◽  
Empirical Corrections

The calculation of the entropy of flexible molecules can be challenging, since the number of possible conformers grows exponentially with molecule size and many low-energy conformers may be thermally accessible. Different methods have been proposed to approximate the contribution of conformational entropy to the molecular standard entropy, including performing thermochemistry calculations with all possible stable conformations, and developing empirical corrections from experimental data. We have performed conformer sampling on over 120,000 small molecules generating some 12 million conformers, to develop models to predict conformational entropy across a wide range of molecules. Using insight into the nature of conformational disorder, our cross-validated physically-motivated statistical model can outperform common machine learning and deep learning methods, with a mean absolute error ≈4.8 J/mol•K, or under 0.4 kcal/mol at 300 K. Beyond predicting molecular entropies and free energies, the model implies a high degree of correlation between torsions in most molecules, often as- sumed to be independent. While individual dihedral rotations may have low energetic barriers, the shape and chemical functionality of most molecules necessarily correlate their torsional degrees of freedom, and hence restrict the number of low-energy conformations immensely. Our simple models capture these correlations, and advance our understanding of small molecule conformational entropy.

Cerebellotrigeminal Dermal Dysplasia (Gómez-López-Hernández Syndrome)

2018 ◽  
Vol 16 (05) ◽  
pp. 362-368 ◽  
Author(s):  
Federica Sullo ◽  
Agata Polizzi ◽  
Stefano Catanzaro ◽  
Selene Mantegna ◽  
Francesco Lacarrubba ◽  
...  
Keyword(s):  
De Novo ◽  
Chromosomal Rearrangements ◽  
Number Of Patients ◽  
Wide Range ◽  
Visual Problems ◽  
Neurodevelopmental Abnormalities ◽  
Clinical Triad ◽  
High Degree ◽  
Motor Handicap

Cerebellotrigeminal dermal (CTD) dysplasia is a rare neurocutaneous disorder characterized by a triad of symptoms: bilateral parieto-occipital alopecia, facial anesthesia in the trigeminal area, and rhombencephalosynapsis (RES), confirmed by cranial magnetic resonance imaging. CTD dysplasia is also known as Gómez-López-Hernández syndrome. So far, only 35 cases have been described with varying symptomatology. The etiology remains unknown. Either spontaneous dominant mutations or de novo chromosomal rearrangements have been proposed as possible explanations. In addition to its clinical triad of RES, parietal alopecia, and trigeminal anesthesia, CTD dysplasia is associated with a wide range of phenotypic and neurodevelopmental abnormalities.Treatment is symptomatic and includes physical rehabilitation, special education, dental care, and ocular protection against self-induced corneal trauma that causes ulcers and, later, corneal opacification. The prognosis is correlated to the mental development, motor handicap, corneal–facial anesthesia, and visual problems. Follow-up on a large number of patients with CTD dysplasia has never been reported and experience is limited to few cases to date. High degree of suspicion in a child presenting with characteristic alopecia and RES has a great importance in diagnosis of this syndrome.

scholarly journals Controlling Teleportation-Based Locomotion in Virtual Reality with Hand Gestures: A Comparative Evaluation of Two-Handed and One-Handed Techniques

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 715
Author(s):  
Alexander Schäfer ◽  
Gerd Reis ◽  
Didier Stricker
Keyword(s):  
Virtual Reality ◽  
Virtual Worlds ◽  
User Preferences ◽  
Interaction Techniques ◽  
Hand Gestures ◽  
Wide Range ◽  
Effectiveness And Efficiency ◽  
High Degree ◽  
Additional Hardware ◽  
Comprehensive Study

Virtual Reality (VR) technology offers users the possibility to immerse and freely navigate through virtual worlds. An important component for achieving a high degree of immersion in VR is locomotion. Often discussed in the literature, a natural and effective way of controlling locomotion is still a general problem which needs to be solved. Recently, VR headset manufacturers have been integrating more sensors, allowing hand or eye tracking without any additional required equipment. This enables a wide range of application scenarios with natural freehand interaction techniques where no additional hardware is required. This paper focuses on techniques to control teleportation-based locomotion with hand gestures, where users are able to move around in VR using their hands only. With the help of a comprehensive study involving 21 participants, four different techniques are evaluated. The effectiveness and efficiency as well as user preferences of the presented techniques are determined. Two two-handed and two one-handed techniques are evaluated, revealing that it is possible to move comfortable and effectively through virtual worlds with a single hand only.

Krypton 85 myocardial blood flow: precordial scintillation versus coronary sinus sampling

1965 ◽  
Vol 209 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Michael D. Klein ◽  
Lawrence S. Cohen ◽  
Richard Gorlin
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Coronary Sinus ◽  
Human Subjects ◽  
Radioactive Decay ◽  
Empirical Correction ◽  
Wide Range ◽  
Actual Flow ◽  
Flow Through ◽  
High Degree

Myocardial blood flow in human subjects was assessed by comparative simultaneous measurement of krypton 85 radioactive decay from coronary sinus and precordial scintillation. Empirical correction of postclearance background from precordial curves yielded a high degree of correlation between flows derived from the two sampling sites (r = .889, P < .001). Comparison of left and right coronary flows in nine subjects revealed similarity in flow through the two vessels over a wide range of actual flow values (r = .945, P < .001).

scholarly journals A new species ofEugenia(Myrtaceae) from south-eastern Brazil

2008 ◽  
Vol 158 (2) ◽  
pp. 306-308
Author(s):  
MARCELO DA COSTA SOUZA ◽  
MARLI PIRES MORIM
Keyword(s):  
New Species ◽  
South Eastern ◽  
Eastern Brazil ◽  
A New Species
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