Exploring the impact of external shading system on cognitive task performance, alertness and visual comfort in a daylit workplace environment

The authors examined the effect of external shading system on cognitive performance, alertness and visual comfort of visual display terminal (VDT) users under two realistic office lighting settings in this study. Daylight was the source of illumination being considered as the most significant and preferred one. A total of 26 participants performed visual and cognitive demanding tasks as well as providing subjective alertness, performance and visual evaluations in a full-scale mock-up VDT workstation. Two trials (with and without shading system) were executed during one experimental session. Results revealed that the use of a shading system improves the performance of a user on colour-naming task requiring sustained attention, while no differential effects were observed on tasks involving other cognitive skills such as search velocity and vigilance. Within-subject performance differences were more pronounced during morning hours. Higher performance was reported in some cognitive tests when the subjective sensation of visual discomfort was lower

Perception of Light in Museum Environments: Comparison between Real-Life and Virtual Visual Experiences

Alternative environments to real-life have been in recent demand in regard to lighting design and in museums. In this study, the effectiveness of the perception of the museum space in simulations or virtual-based environments is studied. Answers to a questionnaire regarding lighting in four different visual experiences are compared: Real-life, virtual-video-based, virtual-photo-based and virtual-render-based. A total of 117 participants were divided into four visual experience groups. Each group answered the same lighting related questions for four exhibition halls in the Natural History Museum of the University of Pisa (Italy), which is housed in the Monumental Charterhouse of Calci. The answers were analyzed using ANOVA and a T-test. The results show that virtual experiences can be acceptable alternatives to real-life experience as the answers were indifferent in more than half of the criteria, and no criterion was affected significantly by experience, regardless of the hall’s characteristics. However, it was found that the hall’s characteristics also had an impact on the perception of the criteria in different experiences. Controlled artificial lighting or uniformly distributed lighting (full day or artificial light) were found to be more indifferent to the experience

Stellar archeology: a cosmological view of dwarf galaxies

The origin of dwarf spheroidal galaxies (dSphs) is investigated in a global cosmological context by simultaneously following the evolution of the Milky Way Galaxy and its dwarf satellites. This approach enable to study the formation of dSphs in their proper birth environment and to reconstruct their own merging histories. The proposed picture simultaneously accounts for several dSph and Milky Way properties, including the Metallicity Distribution Functions of metal-poor stars. The observed features are interpreted in terms of physical processes acting at high redshifts.Comment: 8 pages, 5 figures; "Dwarf Galaxies: Keys to Galaxy Formation and Evolution" JENAM 2010 Symposium S

The atrophic effect of 1,25(Oh)2 vitamin d3 (calcitriol) on c2c12 myotubes depends on oxidative stress

Dysfunctional mitochondrial metabolism has been linked to skeletal muscle loss in several physio-pathological states. Although it has been reported that vitamin D (VD) supports cellular redox homeostasis by maintaining normal mitochondrial functions, and VD deficiency often occurs in conditions associated with skeletal muscle loss, the efficacy of VD supplementation to overcome muscle wasting is debated. Investigations on the direct effects of VD metabolites on skeletal muscle using C2C12 myotubes have revealed an unexpected pro-atrophic activity of calcitriol (1,25VD), while its upstream metabolites cholecalciferol (VD3) and calcidiol (25VD) have anti-atrophic effects. Here, we investigated if the atrophic effects of 1,25VD on myotubes depend on its activity on mitochondrial metabolism. The impact of 1,25VD and its upstream metabolites VD3 and 25VD on mitochondria dynamics and the activity of C2C12 myotubes was evaluated by measuring mitochondrial content, architecture, metabolism, and reactive oxygen species (ROS) production. We found that 1,25VD induces atrophy through protein kinase C (PKC)-mediated ROS production, mainly of extramito-chondrial origin. Consistent with this, cotreatment with the antioxidant N-acetylcysteine (NAC), but not with the mitochondria-specific antioxidant mitoTEMPO, was sufficient to blunt the atrophic activity of 1,25VD. In contrast, VD3 and 25VD have antioxidant properties, suggesting that the efficacy of VD supplementation might result from the balance between atrophic pro-oxidant (1,25VD) and protective antioxidant (VD3 and 25VD) metabolites

A methodology for analysing temporal changes of forest surface using aerial photos for the application of Kyoto protocol: a study case in Northern Italy

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Improvement in the sustainability and stability of acrylic protective coatings for outdoor bronze artworks

Outdoor bronze artworks are an entrenched part of our urban landscape. They are usually covered by a patina resulting from their exposition to the environment. This patina plays an important aesthetic role and may provide some passivation on the surface, nonetheless it does not prevent the degradation processes promoted by external factors such as pollution, light and humidity. One of the strategies to slow down these unwanted processes is the application of protective coatings. The products currently available have some limitations due to the loss of effectiveness over time and poor environmental sustainability. With the aim of proposing more performing alternatives, coatings based on Paraloid (R) B44 modified with corrosion inhibitors and light stabilizers were prepared and characterized. Two non-toxic corrosion inhibitors were studied, 5-mercapto-1-pheniltetrazole (MPT) and 5-ethyl-1,3,4-thiadiazol-2-amine (AEDTA), comparing them with the traditional benzotriazole (BTA). The approach used aimed to identify the blend providing the most stable coatings. The chemical and physical properties of the coatings, such as colour, solubility, glass transition and composition, were studied and monitored over time. All coatings have shown adequate visual properties; however, corrosion inhibitors degrade some other properties of the coatings and need to be used in conjunction with light stabilizers. The permanence of corrosion inhibitors in the coatings over time was also studied by investigating the role of the support. The establishment of specific interactions between inhibitors and the bronze surface lengthens their permanence in the coatings compared to what happens with inert supports. Especially for AEDTA, the inhibitor retention within the coating and at the coating-bronze interface is better than for BTA and MPT. The effect of each of the additives on the photooxidation stability of the coating was evaluated and the most promising inhibitor and stabilizer combination was identified

Continuous-wave room-temperature diamond maser

The maser, older sibling of the laser, has been confined to relative obscurity due to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this it has found application in deep-space communications and radio astronomy due to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid- state maser exploiting photo-excited triplet states in organic pentacene molecules paves the way for a new class of maser that could find applications in medicine, security and sensing, taking advantage of its sensitivity and low noise. However, to date, only pulsed operation has been observed in this system. Furthermore, organic maser molecules have poor thermal and mechanical properties, and their triplet sub-level decay rates make continuous emission challenging: alternative materials are therefore required. Therefore, inorganic materials containing spin-defects such as diamond and silicon carbide have been proposed. Here we report a continuous-wave (CW) room-temperature maser oscillator using optically pumped charged nitrogen-vacancy (NV) defect centres in diamond. This demonstration unlocks the potential of room-temperature solid-state masers for use in a new generation of microwave devices.Comment: 7 pages, 4 figure

Ocorrência do Barley/Cereal yellow dwarf virus e seus vetores em cereais de inverno no Rio Grande do Sul, Santa Catarina, Paraná e Mato Grosso do Sul em 2008.

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The stellar content of the Hamburg/ESO survey VI. The metallicity distribution of main-sequence turnoff stars in the Galactic halo

We determine the metallicity distribution function (MDF) of the Galactic halo based on metal-poor main-sequence turnoff-stars (MSTO) which were selected from the Hamburg/ESO objective-prism survey (HES) database. Corresponding follow-up moderateresolution observations (R ~ 2000) of some 682 stars (among which 617 were accepted program stars) were carried out with the 2.3m telescope at the Siding Spring Observatory (SSO). Corrections for the survey volume covered by the sample stars were quantitatively estimated and applied to the observed MDF. The corrections are quite small, when compared with those for a previously studied sample of metal-poor giants. The corrected observational MDF of the turnoff sample was then compared with that of the giants, as well as with a number of theoretical predictions of Galactic chemical evolution, including the mass-loss modified Simple Model. Although the survey-volume corrected MDFs of the metal-poor turnoff and the halo giants notably differ in the region of [Fe/H] > -2.0, below [Fe/H] ~ -2.0, (the region we scientifically focus on most) both MDFs show a sharp drop at [Fe/H] ~ -3.6 and present rather similar distributions in the low-metallicity tail. Theoretical models can fit some parts of the observed MDF, but none is found to simultaneously reproduce the peak as well as the features in the metal-poor region with [Fe/H] between -2.0 to -3.6. Among the tested models only the GAMETE model, when normalized to the tail of the observed MDF below [Fe/H] ~ -3.0, and with Z_{cr} = 10^{-3.4}Z_{\odot}, is able to predict the sharp drop at [Fe/H] ~ -3.6.Comment: 10 pages, 11 figures, accepted for publication in A&