Twin-Row Production and Optimal Plant Population for Modern Maize Hybrids

Maize (Zea mays L.) is widely grown for food, feed, and fuel, and optimal yield will be required to meet increasing demand due to world population growth and increased biofuel usage. This requires matching of the best maize hybrids with optimal plant population and spacing. Modern maize hybrids have increased “crowding stress” tolerance, and Bt (Bacillus thuringiensis) hybrids now resist European corn borer and corn rootworm which has created interest in altering row configuration and increasing plant population. Three Bt hybrids were evaluated from 2009 to 2010 near Mead, NE at target populations from 69136 to 106173 plants ha-1 in 76 cm single rows and twin rows. Maximum yield occurred at the highest target population in 9 of 12 year, hybrid, and row configuration combinations although target population had a small effect on yield. Varying hybrid, plant population, and row configuration had small and inconsistent effects on grain yield, yield components, plant morphology and leaf area, interception of solar radiation, and stalk lodging. It appears that the major impacts of altering row configuration occur early in the growing season, and plant growth and other factors occurring later in the growing season have a greater impact on yield. Two pairs of near isogenic Bt and non-Bt maize hybrids were evaluated under rainfed and irrigated conditions from 2008 to 2010 at target populations from 49383 to 111111 plants ha-1 near Mead, NE. For all hybrids and environments, yield increased linearly and the highest target population resulted in the greatest grain yield. Bt hybrids had 0.4 Mg ha-1 greater yield than non-Bt hybrids at all populations. Bt hybrids lodged less in three of five environments. Results indicate that twin-row production has little influence on maize yield and growth in Nebraska. In general, maize yield increased linearly with increasing target population although the rate of yield increase varied across experiments, environments and hybrids. Farmers in East-Central Nebraska should consider increasing maize plant population and planting Bt hybrids to optimize maize grain yield

Amino Acids and Layers

Studies conducted over a four-year period with low protein diets for caged layers are summarized in Table 1. The data indicate that the 9.4 percent protein diet with added methionine, lysine and tryptophan would support a rate of egg production nearly the same as a 15.4 percent protein diet. The rate of production from a 12.4 percent protein diet was not improved by raising the protein level to 15.4 percent. Further addition of protein after the amino acid deficiency has been corrected should only cause an increase in loss of nitrogen in the excreta

Replacement of Protein with Amino Acids in Diets for Laying Hens and Turkey Poults

Low protein diets were formulated for experiments with laying hens and turkey poults. The diets were supplemented with equal amounts of protein and different feedstuffs while maintaining equal calculated levels of selected amino acids. Single trails were also reported for factorially applied amino acid supplements to turkey starter and cage-layer diets. The three-year studies indicated that a typical corn-soy layer diet diluted with glucose monohydrate to 9.4 percent protein was deficient in methionine, lysine and tryptophan. Attempts to further improve the rate of egg production by additional supplements of arginine, isoleucine, valine, or diammonium citrate were not successful. The low protein diet for layers was then supplemented with3 or 6 percentage equivalents for protein from common feedstuffs in an effort to improve egg production from approximately 55 percent, on a hen-day basis, to 65 percent or better for 10 months of production. It was apparent that the 9.4 percent protein layer diet was deficient in a substance which could be supplied by several feedstuffs. Supplements of three percentage equivalents of protein from yellow corn, spring wheat, barley, soybean meal, soybean protein and fish meal, soybean protein and fish meal elicited a response in production. Supplements of 6 percentage equivalents of protein from soybean meal, soybean protein or a mixture consisting of a 40:60 ratio of protein from corn and soybean meal did not further improve production. Supplements of 3 percentage equivalents of protein from hydrolyzed feather meal, oats, meat and bone scraps, or milo or of nf-180 did not stimulate marked improvement over that obtained from the 9.4 percent protein amino acid supplemented basal diet. Studies were also made with turkey poults fed low protein starter diets supplemented with amino acids to 40, 60, or 80 percent of the feeding standard proposed by Dunkelgod et al. (1961). Growth rates of poults fed to four weeks of age on 20 percent protein diets were slower for poults fed diets containing 13 percent protein equivalents from hydrolyzed blood meal, corn gluten or meat and bone scraps than were growth rates of poults fed diets with soybean mean, safflower meal or fish meal as the supplementing the diet with amino acids to 60 percent of the standard. Further supplements to 80 percent of the standard did not affect growth rates. Studies were also made with turkey poults which involved factorial application of treatments. The 20 percent protein diet was supplemented with amino acids to 100 percent of the amount calculated for the 28 percent protein corn-soy control diet. The results of the factorial expressed as effects means of body weight indicated that the effects indicate that methionine, lysine, and tryptophan were deficient in the 20 percent protein corn-soy starter diet. Further indications of a deficiency of valine and detrimental effect of excess isoleucine were observed. A similar type of study was made with a 9.4 percent protein diet for caged layers. Supplements of methionine, lysine, valine and inositol were used. The results indicated that variation between groups was not consistently correlated with time or with the four factors in the test. The effect means of hen-day egg production may not have been an adequate measure of response to dietary supplements in this limited study. Free amino acid levels in serum from turkey poults and electrophoretic patterns of egg protein and plasma protein on polyacrylamide gel were found to be poor indicators of the nutritional adequacy of the diets used in this study. Free amino acid levels were not consistent among birds treated alike. Serum protein electrophoretic patterns were essentially the same for all hens and poults regardless of the diet being fed

On the Classification of the Early Tertiary Erinaceomorpha (Insectivora, Mammalia)

Definitions are provided for three Early Tertiary families of Erinaceomorpha. The family Dormaaliidae includes Dormaalius, Macrocranion, Scenopagus, Ankylodon, Crypholestes, Sespedectes, and Proterixoides

Historia de las relaciones científicas entre Cuba y el American Museum of Natural History (AMNH) : 160 años de colección y colaboración (1857-2017)

132 pages : illustrations (some color), color map ; 28 cm.Spanish and English on facing pages. Includes bibliographical references (pages 123-126)

Amino Acid and Protein Requirements of Layers

Studies on this problem have taken two approaches, one using a 9.4% protein basal diet supplemented with 0.19% lysine, 0.25% DL-methionine and 0.04% DL-tryptophane and the other comparing a 14% protein plus methionine diet with a typical 16% protein diet

Desmostylian skeleton

8 p. : ill. ; 26 cm.Includes bibliographical references (p. 7-8)."According to several standard descriptions, desmostylians lack certain specializations shared by proboscideans, sirenians, and hyracoids. These specializations are amastoidy and the serial arrangement of the carpals with the concomitant loss of contact between the lunar and unciform. We argue that original descriptions of desmostylians pertaining to these traits are either in error, or have alternative phylogenetic implications. Hence, comparisons of these conditions do not exclude desmostylians from the superordinal group Tethytheria (proboscideans and sirenians) or the more inclusive Paenungulata (tethytheres and hyracoids)"--P. [1]

Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia

The Cretaceous–Paleogene (KPg) boundary, one of Earth’s five major extinction events, occurred just before the appearance of Placentalia in the fossil record. The Gobi Desert, Mongolia and the Western Interior of North America have important fossil mammals occurring just before and after the KPg boundary (e.g. Prodiacodon, Deltatheridium) that have yet to be phylogenetically tested in a character-rich context with molecular data. We present here phylogenetic analyses of >6000 newly scored anatomical observations drawn from six untested fossils and added to the largest existing morphological matrix for mammals. These data are combined with sequence data from 27 nuclear genes. Results show the existence of a new eutherian sister clade to Placentalia, which we name and characterize. The extinct clade Leptictidae is part of this placental sister clade, indicating that the sister clade survived the KPg event to co-exist in ancient ecosystems during the Paleogene radiation of placentals. Analysing the Cretaceous metatherian Deltatheridium in this character-rich context reveals it is a member of Marsupialia, a finding that extends the minimum age of Marsupialia before the KPg boundary. Numerous shared-derived features from multiple anatomical systems support the assignment of Deltatheridium to Marsupialia. Computed tomography scans of exquisite new specimens better document the marsupial-like dental replacement pattern of Deltatheridium. The new placental sister clade has both Asian and North American species, and is ancestrally characterized by shared derived features such as a hind limb modified for saltatorial locomotion

Human RAD51 rapidly forms intrinsically dynamic nucleoprotein filaments modulated by nucleotide binding state.

Formation of RAD51 filaments on single-stranded DNA is an essential event during homologous recombination, which is required for homology search, strand exchange and protection of replication forks. Formation of nucleoprotein filaments (NF) is required for development and genomic stability, and its failure is associated with developmental abnormalities and tumorigenesis. Here we describe the structure of the human RAD51 NFs and of its Walker box mutants using electron microscopy. Wild-type RAD51 filaments adopt an 'open' conformation when compared to a 'closed' structure formed by mutants, reflecting alterations in helical pitch. The kinetics of formation/disassembly of RAD51 filaments show rapid and high ssDNA coverage via low cooperativity binding of RAD51 units along the DNA. Subsequently, a series of isomerization or dissociation events mediated by nucleotide binding state creates intrinsically dynamic RAD51 NFs. Our findings highlight important a mechanistic divergence among recombinases from different organisms, in line with the diversity of biological mechanisms of HR initiation and quality control. These data reveal unexpected intrinsic dynamic properties of the RAD51 filament during assembly/disassembly, which may be important for the proper control of homologous recombination