Search results for "ECD"
showing 10 items of 195 documents
Latvijas skolu segregācijas iezīmes SSNP 2015 pētījumā
2017
Latvijas skolu segregācijas iezīmes SSNP 2015 pētījumā. Darbā veiktā pētījuma mērķis ir, analizējot OECD Starptautiskās skolēnu novērtēšanas programmas (SSNP) 2015 dabaszinātņu kompetences novērtēšanā iegūtos datus, noteikt faktorus, kuri statistiski nozīmīgi ietekmētu sasniegumu atšķirības starp skolām un būtu izmantojami skolu segregācijas ietekmes uz skolēnu sasniegumiem mazināšanai. Darba izstrādes laikā tika apkopota zinātniskā literatūra par segregāciju, tās iezīmēm un attīstības vēsturi, kā arī aplūkoti izglītības segregācijas piemēri gan Pasaulē, gana arī Latvijā. Darba praktiskajā daļā tika izanalizēti Latvijas OECD SSNP 2015 dati, konkrēti par dabaszinātņu kompetenci, kā arī tika …
Molecular cloning and expression of Tenebrio molitor ultraspiracle during metamorphosis and in vivo induction of its phosphorylation by 20-hydroxyecd…
2000
Using a RT-PCR approach, the Tenebrio molitor homologue of Drosophila Ultraspiracle (TmUSP) was characterized. Its DNA binding domain shows a degree of identity with those of the other insect USPs. However, the ligand binding domain is closer to those of retinoid X receptors. Using an antibody raised against DmUSP, Western blot analysis of proteins from epidermis and other tissues revealed five immunoreactive bands, corresponding to different phosphorylated forms of a unique polypeptide, as shown by lambda-phosphatase treatment. The nuclear form of TmUSP seems unphosphorylated. An in vivo 20-hydroxyecdysone treatment increases considerably and rapidly the phosphorylated forms of TmUSP. This…
The Mutation without childrenrgl Causes Ecdysteroid Deficiency in Third-Instar Larvae of Drosophila melanogaster
2000
Larvae homozygous for the recessive lethal allele without children(rgl) (woc(rgl)) fail to pupariate. Application of exogenous 20-hydroxyecdysone elicits puparium formation and pupation. Ecdysteroid titer measurements on mutant larvae show an endocrine deficiency in the brain-ring gland complex, which normally synthesizes ecdysone, resulting in a failure of the larvae to achieve a threshold whole body hormone titer necessary for molting. Ultrastructural investigation revealed extensive degeneration of the prothoracic cells of the ring gland in older larvae. The woc gene, located in polytene chromosomal region 97F, consists of 11 exons. A 6.8-kb transcript is expressed throughout development…
Measurement error in schooling data: the OECD case
2003
The effect of human capital is difficult to estimate in cross-country analysis due to measurement errors in schooling data. Using data for OECD countries over the period 1960–1990, the reliability of the widely used Barro and Lee's data set and also the new De la Fuente and Domenech's data set is analysed. Results show that both suffer from measurement errors, but the latter seems to reflect the rate of growth of schooling more accurately, especially when taking long differences.
Análisis de la sostenibilidad del sector exterior en la OCDE con técnicas de multicointegración
2022
Este artículo analiza la sostenibilidad externa de un grupo de 23 países de la OCDE durante el periodo 1970-2020. La estrategia empírica adoptada muestra la importancia del desequilibrio acumulado como desencadenante del ajuste externo, en línea con la propuesta de Gourinchas y Rey (2007). Para ello, contrastamos la sostenibilidad externa a través de la relación acumulado-flujo entre las variables que representan las relaciones externas de una economía abierta utilizando varios tipos de contrastes de cointegración y multicointegración. Los resultados obtenidos apuntan hacia la sostenibilidad en sentido débil en el análisis de los flujos, mientras que desde el punto de vista del enfoque acum…
A new ecdysteroid and other constituents from two Dioscorea species
2008
Phytochemical investigation of the rhizome of Dioscorea dumetorum has led to the isolation by several chromatographic steps on normal and reversed phase silica gel of a new ecdysteroid, (20R)-5β,11α,20-trihydroxyecdysone (1), and two known ecdysteroids, ajugasterone C (2) and herkesterone (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR (COSY, TOCSY, HSQC and HMBC). This is the first report on the occurrence of phytoecdysteroids in the Dioscoreaceae family. These compounds were devoid of antifungal activity against three Candida species (Candida albicans, Candida glabrata and Candida tropicalis, MIC > 200 μg/ml).
Identification of proteins and developmental expression of RNAs encoded by the 65A cuticle protein gene cluster in Drosophila melanogaster
1998
0965-1748 (Print) Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S.; Proteins of the third instar larval cuticle of Drosophila melanogaster, LCP5-LCP9, were purified and their N-terminal sequences determined. Three of these proteins (LCP5, 6, and 8) were found to be encoded by two multicopy genes previously mapped to the gene cluster at 65A 5-6 on the left arm of the third chromosome. The analysis of the patterns of developmental expression of the 8 distinct genes at this site showed that all but two were expressed during larval life. The patterns fell into three groups: one where expression was all through larval life, one where expression was primar…
Entre théorie et pratique en ecdotique galloromane
2015
Ce chapitre traite du conditionnement réciproque entre théorie et pratique éditoriales en philologie galloromane (ancien français et ancien provençal) dans une perspective historique, depuis l’introduction de la méthode dite lachmannienne jusqu’à nos jours. On a essayé d’illustrer, d’une part, comment l’expérience éditoriale des philologues ait influencé leur propositions de méthode, et, d’autre part, comment une application trop rigide ou bien peu contrôlée de ces méthodes ait parfois produit des éditions critiques insatisfaisantes sous certains aspects, ou bien elle ait causé des défaillances au niveau de la reconstruction textuelle. À travers la leçon des maîtres de différentes écoles ph…
2-Deoxyecdysone is a circulating ecdysteroid in the beetle Zophobas atratus
1997
A qualitative analysis of ecdysteroids has been performed during the post-embryonic development of the tenebrionid beetle, Zophobas atratus, by high performance liquid chromatography (HPLC) combined with enzyme immunoassay (EIA) using two different antibodies. Three HPLC peaks were found to be immunoreactive, in hemolymph extracts of both sexes. Moreover, these peaks had ecdysteroid-like UV spectra, determined using a photodiode array detector. The use of two different HPLC systems (reverse and normal phases), in combination with two different EIA antibodies, allowed us to identify 20-hydroxyecdysone (20E) and ecdysone (E), as the two main ecdysteroids, but also suggested the presence of 2-…
Ultrastructural changes of the oenocytes of Gryllus bimaculatus DEG (Saltatoria, Insecta) during the moulting cycle
1974
1. The oenocytes of Gryllus bimaculatus are characterized by an abundant smooth-surfaced ER (ATER). In spite of the great cell size the plasma membrane never shows extensive infoldings during the moulting cycle. In addition to mitochondria there are very large numbers of microbodies containing peroxidase but apparently not uricase. Within the second part of the instar the microbodies lie along the clefts which run through the whole cell. 2. The following changes are observed in the course of a moulting cycle: Immediately after hatching the ATER is scarcely developed, some liposomes are located within areas of ATER disappearing some hours later. 20 hours after emergence glycogen deposits app…