The sorting of female careers after first birth : a competing risks analysis of maternity leave duration

A number of contributions have found evidence for motherhood being a critical life event for women's employment careers. This study presents a detailed model for the du- ration of maternity leave in which young mothers can make a transition into a number of states related to employment and unemployment among others. The model incorporates a large number of factors including the legal framework, individual and firm character- istics. We provide a comprehensive picture of the sorting mechanisms that lead to the differentiation of women's employment careers after birth. Our empirical evidence is de- rived from large linked administrative individual labour market data from Germany for a period of three decades. We obtain unprecedented insights how women's skills, the quality of the previous job match, firm level characteristics, labour market conditions and leave legislation are related to the length of maternity duration

Fixing the leak: unemployment incidence before and after the 2006 reform of unemployment benefits in Germany

"Das Gesetz zu Reformen am Arbeitsmarkt schränkte ab Februar 2006 die Bezugshöchstdauern des Arbeitslosengeldes für Ältere stark ein; je nach Altersgruppe um bis zu 14 Monate. Wir untersuchen dieses natürliche Experiment und zeigen: Bei den betroffenen Altersgruppen stiegen die Übergangsraten aus Beschäftigung in Arbeitslosigkeit in den drei Monaten vor der Reform deutlich an: Bei einem durchschnittlichen Arbeitnehmer der Altersgruppe 57 bis 64 war die monatliche Übergangswahrscheinlichkeit sogar um etwa 120 Prozent höher, als ohne Reform zu erwarten gewesen wäre. Im Nachreform-Zeitraum bis Ende 2007 sanken die monatlichen Eintrittsraten Älterer in Arbeitslosigkeit deutlich ab; sie lagen bei den 57-64 Jährigen um gut 20 Prozent niedriger als ohne Reform. Ein Teil der geringeren Eintritte im Nachreform-Zeitraum dürfte darauf zurückzuführen sein, dass Übergänge in die Monate vor der Reform vorgezogen wurden. Da der Gesetzgeber die Bezugshöchstdauern bereits Anfang 2008 teils wieder verlängerte, lässt sich der exakte langfristige Reformeffekt leider nicht identifizieren." (Autorenreferat)"From 2002-2004, the German government passed several laws that curtailed the generosity of the unemployment compensation system. One of the most ambitious changes was a considerable reduction in unemployment benefit entitlement lengths for older unemployed, which was effective during 2006 and 2007. We apply a difference-in-differences approach to show that the highly disputed reform induced a considerable decline in unemployment incidence among older workers. It thus sealed an important leak in the unemployment insurance system. Furthermore, we find a strong anticipation effect; unemployment entries of elderly workers peaked during the months preceding the reform." (author's abstract

Differentiation of Cultured Human Epidermal Keratinocytes at High Cell Densities is Mediated by Endogenous Activation of the Protein Kinase C Signaling Pathway

Normal human epidermal keratinocytes (NHEK) grown in serum-free medium on a plastic substrate spontaneously differentiate at high cell densities in vitro. Because protein kinase C (PKC) regulates murine keratinocyte differentiation triggered by a variety of stimuli, we examined the role of this signaling pathway in density-dependent activation of NHEK differentiation. Relative to subconfluent cultures, confluent NHEK expressed markedly higher levels of multiple differentiation markers assayed by immunoblotting, including keratin 1, loricrin, filaggrin, involucrin, TGK, and SPR-1. Expression of several of these markers continued to increase for several days after cells reached confluency. The total level of several PKC isoforms was not substantially altered in NHEK harvested at different cell densities, based on immunoblotting; however, subcellular fractionation revealed that PKCα underwent a redistribution to the particulate fraction in confluent and postconfluent NHEK cultures, suggesting that this isozyme was activated under these conditions and may be involved in triggering the terminal differentiation program. Supporting this concept, inhibition of PKC function using bryostatin 1 or GF 109203X blocked the induction of keratinocyte differentiation markers at high cell densities. These data suggest that endogenous activation of PKC is responsible for cell density-mediated stimulation of NHEK differentiation, establishing a critical role for this pathway in regulating human as well as murine keratinocyte differentiation

Avaliação de tipologias da Floresta Ombrófila Mista por meio de processamento digital de imagens de alta resolução.

Resumo

Índice para a avaliação de segmentação de imagens.

O presente artigo descreve o desenvolvimento de um índice para avaliar quantitativamente resultados gerados por algoritmos segmentadores, tomando-se por base o Índice para Avaliação de Segmentação (IAVAS). As variáveis componentes do novo índice, denominado IAVASmod, tiveram seus valores obtidos com a aplicação do método empírico de discrepância, que é dependente da existência de uma imagem de referência. Sobre essa imagem, também chamada segmentação-referência, efetua-se a comparação numérica relativa (em percentagem) dos resultados produzidos pelos valores de limiares aplicados ao algoritmo segmentador. A avaliação quantitativa dos resultados da segmentação envolve os seguintes parâmetros: número de polígonos, distância entre centroides, diferença em área, diferença em perímetro e faixa de coincidência. Métodos de avaliação quantitativa apresentam resultados mais consistentes em análises envolvendo segmentações, eliminando a subjetividade do analista, que ocorre quando se aplicam métodos qualitativos para a aceitação ou rejeição de valores de limiares. Palavras-chave: Segmentação; avaliação quantitativa; índice IAVAS