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| Registros recuperados: 268 | |
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| Brieger,F. G.. |
| Na aplicação do X2-teste devemos distinguir dois casos : Á) Quando as classes de variáveis são caracterizadas por freqüências esperadas entre p = 0,1 e p = 0,9, podemos aplicar o X2-teste praticamente sem restrição. É talvez aconselhável, mas não absolutamente necessário limitar o teste aos casos nos quais a freqüência esperada é pelo menos igual a 5. e porisso incluimos na Táboa II os limites da variação de dois binômios ( 1/2 + 1/2)n ( 1/4 + 3/4)n para valo r es pequenos de N e nos três limites convencionais de precisão : ,5%, 1% e 0,1%. Neste caso, os valores dos X2 Índividuais têm apenas valor limitado e devemos sempre tomar em consideração principalmente o X2 total. O valor para cada X2 individual pode ser calculado porqualquer das expressôe... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761948000100002 |
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| Castro,Yone G.P. de. |
| In the present paper the behaviour of the chromosomes in the spermatogenesis of the Myriapod Rhinocricus Padbergi Verhoeff, 1938 is studied. The primary spermatocytes are provided with 10 independent bivalents which separate normally giving rise to equivalent secondary spermatocytes. No indication of sex chromosomes has been found. Fusion of two bivalents or of four, two by two, has been observed, giving origin to secondary spermatocytes with 9 and 8 chromosomes respectively, in which fused chromosomes could be discovered. For analysing the facts the chomosomes of both, primary and secondary metaphases were separately counted from a total of 190 celis of four individuals and statistically treted. The X2-test gave insignificant results. Twenty chomosomes... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761948000100004 |
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| Kerr,Warwick Estevam. |
| 1° - Cita-sé a evolução das abelhas segundo MICÍÍENÉR" (1944). 2.° - A evolução dos Melíponíneos é estudada sob o ponto de vista da sua biologia, estabelecendo-se o tipo do meliponíneo primitivo. 3.° - São feitas considerações sobre a distribuição geográfica dos meliponíneos, entrando-se em detalhes sobre os seus fosseis, sobre a influência dos deslocamentos geológicos do cenozoico sobre sua distribuição, com particular referência ao seu estabelecimento na América do Sul. Considera-se também o e$eito das glaciações e a descontinuidade por ela provocada na distribuição dos meliponíneos. 4.° - São feitas hipóteses sobre a época em que se formaram as Meliponas, sobre o processo de determinação das castas e sua influência na evolução das mesmas. O tipo M.... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761948000100005 |
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| Brieger,F. G.. |
| 1) O equilíbrio em populações, inicialmente compostas de vários genotipos depende essencialmente de três fatores: a modalidade de reprodução e a relativa viabilidade e fertilidade dos genotipos, e as freqüências iniciais. 2) Temos que distinguir a) reprodução por cruzamento livre quando qualquer indivíduo da população pode ser cruzado com qualquer outro; b) reprodução por autofecundação, quando cada indivíduo é reproduzido por uma autofecundação; c) finalmente a reprodução mista, isto é, os casos intermediários onde os indivíduos são em parte cruzados, em parte autofecundados. 3) Populações heterozigotas para um par de gens e sem seleção. Em populações com reprodução cruzada se estabelece na primeira geração um equilíbrio entre os três genotipos, segundo a... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761948000100003 |
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| Boock,O. J.. |
| This paper presents the results obtained from six replicated experimental plantings of Irish potatoes in the State of São Paulo, Brazil. The potatoes tubers employed as seed in these test plantings were selected from the crop produced from the original tubers introduced from Holland in 1947. The results obtained from plantings in February 1947 made of the original seed pieces were the subject of a previous publication. The current tests reported herein were carried out in the same areas as those previously reported. The date of the second planting was, September 1947 and the second crop was harvested in February and March of 1948. The results obtained from the second plantings were similar to those secured from the original tests. Phytopthora infection was... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100004 |
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| Roston,P. J.. |
| A comparison has been made between faced hoes manufactured in Brazil and those manufactured in Great Britain. The Brazilian hoes lack uniformity in the raw materials employed in subsequent heat treatments and in the finishing processes. The British hoes were used as a standard for all comparison. Differences between Brazilian and British hoes were due in part to the differences in raw material employed and in part to the different methods of fabrication. In the author's opinion, the Brazilian hoes are of poorer quality because the raw material are very heterogeneous. They come from several sources and there is no process for selection of raw materials. In this regard it is suggested in this paper that the Brazilian factories should buy the raw material at... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100001 |
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| Franco,C. M.. |
| It has been noticed in the greenhouse of the "Instituto Agronômico de Campinas" that many species of plants developed poorly when planted in seed beds that have been repeatedly used without change of soil. In many cases even the seeds would not germinate in such seed beds. Experiments have showed that the; lack of normal plant development in these beds is the result of the increase in soil salinity. This salinity may be due to additions of fertilizers or to salts introduced in the ordinary applications of water. It was found that the soil solution had an osmotic pressure of 13.5 athmospheres at the wilting point. The tests showed that common bean (Phaseolus vulgaris L.) plants were more susceptible to the soil salinity than were the soybean and the corn... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100002 |
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| Medina,J. C.. |
| Sisal (Agave sisalana Perrine) accounts for about one half of the world's production of hard fibers. In spite os its economic importance pratically no research work has been carried out on this plant. Very little is known about the agronomic problems of its cultivation, while the physiological and genetic problems are nearly unknown. This is perhaps due to the fact that A. sisalana is a perennial plant with a life cycle of 5-8 years and the carrying out of field research work requires a great deal of time and is very expensive. This paper, the first of a series to be published on the agronomic problems of sisal cultivation, presents the data obtained from field trials on distance of planting and its relation to weight and number of leaves produced. The... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100007 |
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| Boock,O. J.. |
| The author reports the results of six experiments with eight yellow fleshed potato varieties from Holland, conducted at six different locations in the State of São Paulo. Time of planting was February-March, less favorable than August-September, because of climatic conditions during the growth period (somewhat dry weather). For this reason, yields were not good. Observations were made on development; resistance, precocity and production of varieties, as well as specific gravety of tubers. Under the conditions of the experiments the varieties Voran and Alpha were the least susceptible to Phytpphthora while Eersteling, and Saskia were the most susceptible. The Doré, Eersteling, Saskia and Geelblon were found to be early maturing varieties while Alpha, Voran... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100003 |
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| Castro,G. Paiva; Correia,F. A.. |
| Tests were made on samples of ramie fibers (Boehmeria nivea Hook., var. locally known as Murakami), obtained from three month old plants grown at Campinas, State of São Paulo. The harvested material was processed and the fibers were degummed and bleached by the methods described. The physical and chemical tests made on six samples of the fibers gave the following average results : PHYSICAL TESTS Length maximum.................................. 360 mm average .................................. 200 mm minimum .................................. 90 mm Width maximum ................................. 63 mm average................................... 32 mm minimum .................................. 16 mm Tensile Strength maximum .................................... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100008 |
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| Franco,C. M.; Loomis,W. E.. |
| Moderate amounts of KH2PO4 (0.5 to 0.7 millimols) caused iron chlorosis of seedlings in solutions less acid than pH 5.5-6.0. The trouble could be avoided by omitting the phosphorus entirely and adding it separately after 2-4 days. Even with this modification the Knop type of solution (Hoagland, 2) caused persistent chlorosis in soybeans and broccoli. In the commonly used Shive solution (R5-C2) a large excess of KH2PO4 holds the pH of the solution between 4.5 and 5.0 and chlorosis is moderate to slight. The Shive solution contains 36 times as much phosphorus as the Hoagland and 6-week-old plants growing in it absorbed 15 times as much to make a slightly poorer growth. The addition of as little as 0.125 g per liter of NH4NO3 resulted in decidedly acid... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100006 |
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| Santos,S. Ribeiro dos; Fraga Jr.,C. G.. |
| This paper describes an experiment with factorial design and two levels of treatment, used in testing fertilizer applications for tobacco seed beds. The fertilizers employed were : Chilean nitrate, superphosphate, potassium chloride, and cotton seed meal. Tobacco plants were grown in ten liter clay pots containing a steam sterilized soil composed of equal parts* of thoroughly mixed sub-soil and surface washed sand. Each of the sixteen treatments tested was applied to six pots and these were divided into three replications of two pote each. Measurements of height and weight of the plants were taken about two months after the seed germinated. An analysis of the data obtained is presented and shows that under the conditions of the test, all fertilizer... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100009 |
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| Registros recuperados: 268 | |
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