Influência da minhoca Pontoscolex corethrurus na distribuição do acaricida dicofol em um Argissolo Effects of earthworm Pontoscolex corethrurus on distribution of acaricida dicofol in a Podzolic soil

O objetivo deste trabalho foi estudar a importância da minhoca Pontoscolex corethrurus na distribuição do pesticida dicofol em um Argissolo. Como modelo foram utilizados microcosmos contendo solo tamizado e acondicionado na densidade 1,25 g cm-3. Em microcosmos com e sem Pontoscolex corethurus, foram aplicados 14C-dicofol, e após um período de 52 dias fez-se uma simulação de chuvas torrenciais. Na camada de 0-1 cm, recuperou-se 75% da radioatividade no solo sem minhoca, e no solo com minhoca, a recuperação foi 9% inferior. Nas camadas mais profundas, os valores da radioatividade ficaram abaixo de 20%, e as diferenças entre os tratamentos não ultrapassaram 2%. Esta espécie de minhoca, muito freqüente no Brasil, mostrou não ter influência relevante na distribuição do pesticida no solo.<br>The aim of this work was to study the influence of earthworm on pesticides distribution in a Podzolic soil. The experimental model used was a microcosm filled with sieved soil to a final density of 1.25 g cm-3. In microcosms with or without Pontoscolex corethurus 14C-dicofol was applied, and after a period of 52 days strong rain simulation was performed. In the layer of 0-1 cm 75% of the radioactivity in the soil without earthworms were recovered, and in the soil with earthworms the recovery was 9% inferior. In the deepest layers the values of the radioactivity were below 20% and the differences among the treatments did not surpass 2%. This earthworm species of large occurrence in Brazil showed no important influence on the distribution of the pesticide in soil

The geography of job creation and destruction in the U.S. manufacturing sector, 1967–1997

Much geographical research focuses on the causes of geographical differences in net employment change. While net employment change is an important indicator of regional growth and decline, it masks the underlying process of creative destruction resulting in tremendous employment turnover rates. Labor economists and those who work in industrial organization emphasize the importance of theorizing the individual processes of job creation and destruction to uncover technological and institutional differences among industries and over the business cycle. This work demonstrates that over the course of a year, 10 percent of all jobs are destroyed and close to 10 percent of jobs are newly created. This article bridges the work of geographers on net employment change and the nongeographical work in industrial organization and provides the first comprehensive account of regional and metropolitan differences of job creation and destruction in U.S. manufacturing. Plant level data of the U.S. Census Bureau show that geographical differences in net employment change are primarily the result of differences in job creation rates and to a lesser extent in job destruction rates, that different types of plants drive the job creation process in different metropolitan areas, and that the snowbelt/sunbelt dichotomy collapses in the 1990s with selected midwestern urban areas among the fastest growing areas in the country

Relationship between bacterial diversity and function under biotic control: the soil pesticide degraders as a case study

In soil, the way biotic parameters impact the relationship between bacterial diversity and function is still unknown. To understand these interactions better, we used RNA-based stable-isotope probing to study the diversity of active atrazine-degrading bacteria in relation to atrazine degradation and to explore the impact of earthworm-soil engineering with respect to this relationship. Bulk soil, burrow linings and earthworm casts were incubated with 13C-atrazine. The pollutant degradation was quantified by liquid chromatography–mass spectrometry for 8 days, whereas active atrazine degraders were identified at 2 and 8 days by sequencing the 16S ribosomal RNA in the 13C-RNA fractions from the three soil microsites. An original diversity of atrazine degraders was found. Earthworm soil engineering greatly modified the taxonomic composition of atrazine degraders with dominance of α-, β- and γ-proteobacteria in burrow linings and of Actinobacteria in casts. Earthworm soil bioturbation increased the γ-diversity of atrazine degraders over the soil microsites generated. Atrazine degradation was enhanced in burrow linings in which primary atrazine degraders, closely related to Pelomonas aquatica, were detected only 2 days after atrazine addition. Atrazine degradation efficiency was not linearly related to the species richness of degraders but likely relied on keystone species. By enhancing soil heterogeneity, earthworms sustained high phylogenetic bacterial diversity and exerted a biotic control on the bacterial diversity–function relationships. Our findings call for future investigations to assess the ecological significance of biotic controls on the relationships between diversity and function on ecosystem properties and services (for example, soil detoxification) at larger scales

Office Lighting - current state and problems

Office lighting is a rapidly developing field in which new technologies are constantly introduced. In this work a review of the state of office lighting technology has been made, both generally and with a case example. The HUT Valotalo was used as the case. A survey was made to find out the problems and development needs of office lighting. This survey included all actors active in the various phases of the life cycle of an office lighting installation. The survey did not reveal anyone significant problem; the problems are associated more with methods than the devices.Toimistovalaistus kehittyy nopeasti ja uusia teknologioita kehitetään markkinoille jatkuvasti. Työssä on luotu katsaus toimistovalaistusteknologian tilaan vuonna 2001. sekä yleensä että esimerkkikohteen kautta. Esimerkkikohteena käytettiin TKK:n Valotaloa. Tämän lisäksi työssä tehtiin kyselytutkimus toimistovalaistustekniikassa ilmenevien ongelmien ja kehitystarpeitten kartoittamiseksi. Tutkimus käsitti kaikki valaistusasennuksen elinkaareen liittyvät tahot. Valaistusteknologiassa ei ole yhtä merkittävää ongelmakohtaa, ja ongelmat ilmenevat yleensä enemmän toimintatavoissa kuin itse laitteissa