Search results for "ECD"
showing 10 items of 195 documents
Exogenous makisterone A accelerates early embryonic development in the milkweed bugOncopeltus fasciatus
1982
Reproducing females ofOncopeltus fasciatus which were treated with exogenous makisterone A and 20-hydroxyecdysone laid eggs with considerably elevated ecdysteroid contents. The early embryonic development was markedly accelerated when the mother was treated with makisterone A, whereas 20-hydroxyecdysone had no influence.
Hysteresis vs. natural rate of unemployment: new evidence for OECD countries
2004
Abstract The paper tests hysteresis effects in unemployment using panel data for 19 OECD countries. We apply a sequential procedure based in two multivariate augmented Dickey-Fuller test (ADF)-type panel unit root tests in a SURE framework. We strongly reject the joint null of hysteresis and find that only seven countries present evidence of hysteresis.
DNA Content and Synthesis in Several Tissues and Variation of Moulting Hormone-Level in Gryllus bimaculatus DEG (Ensifera, Insecta)
1983
The mode of growth of several tissues in Gryllus bimaculatus was investigated during postembryonic development by cytophotometric methods. In contrast to the situation in holo- metabolous insects, the tissues growing by endomitosis reach only moderate levels of polyploidy. In this case the growth of tissues is achieved by mitotic divisions of small cells with subsequent polyploidization. The time courses of DNA synthesis were measured within the 3rd and, for comparison, the 8th larval instar by incorporation of labelled thymidine followed by autoradiography. Hemocytes, cells of the regeneration crypts of the midgut, gonads and nervous tissue showed a continuous incorporation rate; by contra…
Six3 demarcates the anterior-most developing brain region in bilaterian animals
2010
Abstract Background The heads of annelids (earthworms, polychaetes, and others) and arthropods (insects, myriapods, spiders, and others) and the arthropod-related onychophorans (velvet worms) show similar brain architecture and for this reason have long been considered homologous. However, this view is challenged by the 'new phylogeny' placing arthropods and annelids into distinct superphyla, Ecdysozoa and Lophotrochozoa, together with many other phyla lacking elaborate heads or brains. To compare the organisation of annelid and arthropod heads and brains at the molecular level, we investigated head regionalisation genes in various groups. Regionalisation genes subdivide developing animals …
The comparison of beta-thymosin homologues among metazoa supports an arthropod-nematode clade.
2000
The definition of an Ecdysozoa clade among the protostomians, including all phyla with a regularly molted alpha-chitin-rich cuticle, has been one of the most provocative hypotheses to arise from recent investigations on animal phylogeny. Here we present evidence in favor of an arthropod-nematode clade, from the comparison of beta-thymosin homologues among the Metazoa. Arthropods and nematodes share the absence of the highly conserved beta-thymosin form found in all other documented bilaterian phyla as well as sponges, and the possession of a very unusual, internally triplicated homologue of the beta-thymosin protein, unknown in other phyla. We argue that such discrete molecular character is…
Diflubenzuron-Induced alterations during in vitro development ofTenebrio molitor pupal integument
1987
The effects of diflubenzuron (DFB) in Tenebrio molitor pupae were first investigated on cuticle secretion induced by 20-hydroxyecdysone in vitro. The sternal integuments were treated by DFB either 3 days before culture or during culture. DFB, when applied before culture, did not prevent the molting hormone from inducing a new cuticle deposition by integument explants in vitro. However, this cuticle showed several architectural alterations and a thickness reduction. When applied during the culture in the presence of 20-hydroxyecdysone, DFB at high dose (≥ 20 μg/ml) was able to inhibit cuticle secretion, but lower doses (⩽ 10 μg/ml) resulted in epicuticle deposition. These observations confir…
New evidence on international R&D spillovers, human capital and productivity in the OECD
2002
Abstract In this article we show how the use of more reliable data on average years of schooling can change the conclusions about the magnitude of international R&D spillovers based on previous evidence, while pointing to a superior role of human capital.
Development of antennal sensilla during moulting inNeomysis integer (Leach) (Crustacea, Mysidacea)
1980
The sensilla are associated with 6 enveloping cells. The innermost enveloping cell (e 1) secretes the dendritic sheath (=thecogen cell). All other enveloping cells are involved in the formation of the outer cuticular apparatus in secreting the cuticle of a definite region of the new hair shaft. The development of the new sensilla begins when an exuvial space expands between old cuticle and epithelium. The newly forming hair shafts lie folded back in an invagination of the epidermal tissue. Only a distal shaft part projects into the free exuvial space. The cuticle of the distal and middle shaft region is secreted by the three middle enveloping cells (e 2–e 4) (=trichogen cells), which are ar…
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…
Kukuļņemšanas un kukuļdošanas krimināltiesiskais regulējums
2019
Maģistra darba “Kukuļņemšanas un kukuļdošanas krimināltiesiskais regulējums” mērķis ir izpētīt un analizēt tādus korupcijas noziedzīgus nodarījumus kā kukuļņemšana un kukuļdošana, lai izprastu, ar kādam problēmām var saskarties tiesību normu piemērotāji, kvalificējot šos noziedzīgus nodarījumus. Kvalifikācijas problēmas ir dažādas: kukuļdošanas un kukuļņemšanas norobežošana no citiem noziedzīgiem nodarījumiem, nodoma analīze, brīdis, ar kuru kukuļdošana atzīstama par pabeigtu noziegumu, speciālā subjekta identificēšana, kukuļa pieprasīšanas un kukuļa izspiešanas norobežošana. Aplūkojot ārvalsts kukuļošanas krimināltiesisko regulējumu, nacionālo regulējumu un tiesu praksi, autors izdarīja sa…