The Expanding Workweek? Understanding Trends in Long Work Hours Among U.S. Men, 1979-2004

According to Census and CPS data, the share of employed American men regularly working more than 48 hours per week is higher today than it was 25 years ago. Using CPS data from 1979 to 2006, we show that this increase was greatest among highly educated, highly-paid, and older men, was concentrated in the 1980s, and was largely confined to workers paid on a salaried basis. We rule out a number of possible explanations of these changes, including changes in measurement, composition effects, and internet-facilitated work from home. Among salaried men, increases in long work hours were greatest in detailed occupations and industries with larger increases in residual wage inequality and slowly-growing real compensation at 'standard' (40) hours.

A informação informal e a monitoração do ambiente: fontes e exploração/ disseminação

Dentre todas as atividades que uma organização realiza, a monitoração do ambiente certamente deveria ser uma delas. Essa atividade, que tem como principal entrada [e também saída] a informação, raramente é corretamente desenvolvida. Muitos são os fatores que a influenciam e um deles é o excesso de informação disponível no mercado, o que dificulta a monitoração, levando os indivíduos a recorrerem a informações não-estruturadas, informais, provenientes das mais diversas fontes. O objetivo deste artigo é buscar compreender, por meio da identificação de algumas dimensões da atividade de monitoração do ambiente, o uso da informação informal por executivos da área de TI. Por se tratar de um estudo de natureza exploratória e qualitativa, a coleta de dados foi realizada por meio de entrevistas em profundidade com executivos da área. Os resultados, analisados à luz das dimensões identificadas, permitiu que se obtivesse um panorama do uso da informação informal na monitoração do ambiente

Optically driven ultra-stable nanomechanical rotor

Nanomechanical devices have attracted the interest of a growing interdisciplinary research community, since they can be used as highly sensitive transducers for various physical quantities. Exquisite control over these systems facilitates experiments on the foundations of physics. Here, we demonstrate that an optically trapped silicon nanorod, set into rotation at MHz frequencies, can be locked to an external clock, transducing the properties of the time standard to the rod's motion with the remarkable frequency stability $f_{\rm r}/\Delta f_{\rm r}$ of $7.7 \times 10^{11}$. While the dynamics of this periodically driven rotor generally can be chaotic, we derive and verify that stable limit cycles exist over a surprisingly wide parameter range. This robustness should enable, in principle, measurements of external torques with sensitivities better than 0.25zNm, even at room temperature. We show that in a dilute gas, real-time phase measurements on the locked nanorod transduce pressure values with a sensitivity of 0.3%.Comment: 5 pages, 4 figure

IAMCR debate o diálogo entre culturas

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Fluxos radiofônicos em países lusófonos

Este artigo apresenta os resultados de uma pesquisa empírica voltada para a observação de fluxos internacionais de conteúdo na programação transmitida via Internet por emissoras convencionais de países lusófonos. A pesquisa foi realizada em Janeiro de 2007, valendo-se da metodologia proposta por Kuhn (2005), a qual se baseia na amostragem de websites das rádios, submetidos a um protocolo de observação para a atribuição de perfis relacionados ao âmbito de cada programação. Os resultados são discutidos comparativamente em relação aos obtidos por Kuhn (2005)

Cavity-assisted manipulation of freely rotating silicon nanorods in high vacuum

Optical control of nanoscale objects has recently developed into a thriving field of research with far-reaching promises for precision measurements, fundamental quantum physics and studies on single-particle thermodynamics. Here, we demonstrate the optical manipulation of silicon nanorods in high vacuum. Initially, we sculpture these particles into a silicon substrate with a tailored geometry to facilitate their launch into high vacuum by laser-induced mechanical cleavage. We manipulate and trace their center-of-mass and rotational motion through the interaction with an intense intra-cavity field. Our experiments show optical forces on nanorotors three times stronger than on silicon nanospheres of the same mass. The optical torque experienced by the spinning rods will enable cooling of the rotational motion and torsional opto-mechanics in a dissipation-free environment.Comment: 8 page

One book, two language varieties

This paper presents a comparative study of alignment pairs, either contrasting expressions or stylistic variants of the same expression in the European (EP) and the Brazilian (BP) varieties of Portuguese. The alignments were collected semi-automatically using the CLUE-Aligner tool, which allows to record all pairs of paraphrastic units resulting from the alignment task in a database. The corpus used was a children’s literature book Os livros que devoraram o meu pai (The Books that Devoured My Father) by the Portuguese author Afonso Cruz and the Brazilian adaptation of this book. The main goal of the work presented here is to gather equivalent phrasal expressions and different syntactic constructions, which convey the same meaning in EP and BP, and contribute to the optimisation of editorial processes compulsory in the adaptation of texts, but which are suitable for any type of editorial process. This study provides a scientific basis for future work in the area of editing, proofreading and converting text to and from any variety of Portuguese from a computational point of view, namely to be used in a paraphrasing system with a variety adaptation functionality, even in the case of a literary text. We contemplate “challenging” cases, from a literary point of view, looking for alternatives that do not tamper with the imagery richness of the original version .info:eu-repo/semantics/acceptedVersio

Continuous-flow precipitation of hydroxyapatite in ultrasonic microsystems

This paper describes the continuous-flow precipitation of hydroxyapatite Ca5(PO4)3OH (HAp) in two ultrasonic microreactors using diluted aqueous solutions of calcium and phosphate at 37 °C. Precipitation of HAp was first carried out in a tubular microreactor immersed in an ultrasonic bath, where single-phase (laminar) flow and segmented gas-liquid flow were both evaluated. The single-phase flow study was then conducted in a novel microfluidic device developed at MIT. It consists of a Teflon stack microreactor with an integrated piezoelectric element (Teflon microreactor), thereby allowing the direct transmission of ultrasound to the reactor. Both microsystems produce single-phased calcium-deficient carbonated HAp under near-physiological conditions of temperature and pH. In addition, particle aggregation and primary particle size were significantly reduced in the segmented-flow tubular microreactor and in the Teflon microreactor. The as-prepared particles mostly consisted of rod-like shape nanoparticles with dimensions below 100 nm in length and around 20 nm in width. Further, the microreactors used yielded HAp particles with improved characteristics text was removed, namely higher crystallinity and less carbonate contamination, when compared to the HAp particles produced in a stirred tank batch reactor.This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/42992/2008) through the MIT-Portugal Program, Bioengineering Systems Focus Area. The authors are thankful to Dr. Speakman for his help with the X-ray measurements and with the interpretation of the results. S.K. acknowledges funding from the Swiss National Science Foundation (SNF)

Full rotational control of levitated silicon nanorods

We study a nanofabricated silicon rod levitated in an optical trap. By manipulating the polarization of the light we gain full control over the ro-translational dynamics of the rod. We are able to trap both its centre-of-mass and align it along the linear polarization of the laser field. The rod can be set into rotation at a tuned frequency by exploiting the radiation pressure exerted by elliptically polarized light. The rotational motion of the rod dynamically modifies the optical potential, which allows tuning of the rotational frequency over hundreds of Kilohertz. This ability to trap and control the motion and alignment of nanoparticles opens up the field of rotational optomechanics, rotational ground state cooling and the study of rotational thermodynamics in the underdamped regime.Comment: 5 pages, 4 figures, 4 Supplementary pages, 4 Supplementary figure