980 research outputs found
MADEC. Material Design Culture
No full textDue to the increased complexity of materials and production processes, the responsibility of the development of a design is often left in the hands of technicians and production personnel. This lack of knowledge about materials thus effectively creates a barrier between the designer and the product. Bridging this gap represents a challenge to designers and especially to the design schools. Designers cannot know everything but they can open their minds and develop a more conscious understanding of this new field of design practice starting from a cultural point of view. This paper wants to present a re-search promoted by the Design Department of Politecnico di Milano and funded by FARB (University Funds for Basic Re-search), for the creation of a Research Centre named MADEC, with the ambition of recognizing peculiarities of Italian Mate-rial Design Culture, and tracking their evolution in the contemporary era of “tailor made materials” as technological para-digma. The paper is divided into three parts: the first part concerns reasons, motivations and the state of the art of the research; the second part describes in detail the research activities developed during the first year of the project; and the third part is dedicated to conclusions with some critical considerations and future actions
Global maps of internal tide generation and dissipation
No full textThe dataset consists of global two-dimensional maps of internal tide energy sources and sinks, at half-degree horizontal resolution. Estimated energy sources are provided for the three most energetic tidal constituents: M2, S2 and K1. They are decomposed into vertical normal modes. Units are Watts per square meter. Estimated energy sinks are provided for each of M2, S2 and K1 and for 'All constituents'. 'All constituents' is an extrapolation to the eight most energetic tidal constituents, obtained as a weighted sum of M2, S2 and K1 fields. Energy sinks are depth-integrated and decomposed into five process contributions: (i) local dissipation of high modes; (ii) dissipation of low modes via wave-wave interactions; (iii) dissipation of low modes via scattering by abyssal hills; (iv) dissipation of low modes via critical reflection; (v) dissipation of low modes via shoaling. Units are Watts per square meter. Methods and documentation can be found in the following publication: de Lavergne, C., Falahat, S., Madec, G., Roquet, F., Nycander, J., Vic, C. Toward global maps of internal tide energy sinks. Ocean Modelling, 137, 52-75 (2019). doi:10.1016/j.ocemod.2019.03.010. Provided maps of energy sinks correspond to the reference (REF) experiment described in the article.</span
Global estimates of internal tide generation rates at 1/30º resolution
No full textThe dataset contains global estimates of barotropic-to-baroclinic tidal energy conversion at 1/30-degree resolution. Three types of estimates are available: 1. Non-modal conversion rates calculated by Falahat et al. (2014) following the method of Nycander (2005). A map for each of the eight most energetic tidal constituents (M2, S2, K1, O1, N2, K2, P1, Q1) is provided. 2. Mode-by-mode conversion rates calculated by Falahat et al. (2014). A map for each of the three most energetic tidal constituents (M2, S2, K1) and each of vertical normal modes 1, 2, 3, 4, 5 and 6-10 is provided. 3. Mode-by-mode conversion rates calculated by Falahat et al. (2014), to which an ad hoc correction to eliminate negative conversion rates has been applied (following de Lavergne et al., 2019). The correction preserves basin-integrated, depth-dependent conversion rates. A map for each of the three most energetic tidal constituents (M2, S2, K1) and each of vertical normal modes 1, 2, 3, 4, 5 and 6-10 is provided. All maps were computed using the WOCE global climatology of stratification, the ETOPO2v2 bathymetry product and the TXO6.2 atlas of barotropic tidal velocities. Detailed methods and documentation can be found in the following publications: Nycander, J. Generation of internal waves in the deep ocean by tides. Journal of Geophysical Research 110, C10028 (2005). doi:10.1029/2004JC002487 Falahat, S., Nycander, J., Roquet, F., Moundheur, Z. Global calculation of tidal energy conversion into vertical normal modes. Journal of Physical Oceanography 44, 3225-3244 (2014). doi:10.1175/JPO-D-14-0002.1 de Lavergne, C., Falahat, S., Madec, G., Roquet, F., Nycander, J., Vic, C. Toward global maps of internal tide energy sinks. Ocean Modelling,137, 52-75 (2019). doi:10.1016/j.ocemod.2019.03.010.</span
Impact of isopycnal mixing on the tropical ocean circulation
No full textThe sensitivity of tropical ocean dynamics to the ocean lateral mixing orientation is explored using a z-coordinate climate-type ocean general circulation model. Compared to a simulation using horizontal mixing on both tracers and dynamics (HOR), a rotation of the tracer tensor in which mixing occurs along isopycnals (ISOT) improves the structure of the off-equatorial density field, which consequently enhances the off-equatorial circulation through geostrophy. However, the dynamics at the equator in ISOT are degraded compared to observations, as the upper part of the Equatorial Undercurrent (EUC) is too deep and the South Equatorial Current (SEC) is too intense. Next, isopycnal diffusion on momentum is implemented (ISOMT). An examination of the momentum balance at the equator shows that this change in lateral diffusion direction significantly reduces the meridional diffusive flux of momentum at the top of the EUC. This intensifies the EUC, which, in turn, weakens the SEC along the equator through vertical diffusion. The equatorial degradations observed in ISOT disappear. Compared to ISOT and HOR, the separation of the two SEC branches and the equatorial current magnitude in the surface layers are much better reproduced. Moreover, in contrast to the results from ISOT and HOR, isopycnal momentum mixing allows the existence of both horizontal up-gradient and down-gradient eddy momentum fluxes, notably improving the vertical profile of the lateral viscosity term. The ISOMT experiment is therefore shown to be the closest to observations. These results suggest that isopycnal mixing should be used on both tracers and momentum to better simulate the observed eddy effects and the tropical circulation in climate models. <br/
A modeling study of the impact of tropical instability waves on the heat budget of the eastern Equatorial Pacific
No full textA numerical simulation is used to investigate the mixed layer heat balance of the tropical Pacific Ocean including the equatorial cold tongue and the region of vortices associated with tropical instability waves (TIWs). The study is motivated by a need to quantify the effects that TIWs have on the climatological heat budget of the cold tongue mixed layer; there has been some discrepancy between observations indicating very large equatorward heat transport by TIWs and models that disagree on the full three-dimensional budget. Validation of the model reveals that the TIW-induced circulation patterns are realistic but may have amplitudes about 15% weaker than those in the observations. The SST budget within tropical instabilities is first examined in a frame of reference moving with the associated tropical instability vortices (TIVs). Zonal advection of temperature anomalies and meridional advection of temperature by current anomalies dominate horizontal advection. These effects strongly heat the cold cusps and slightly cool the downwelling areas located at the leading edge of the vortices. Cooling by vertical mixing is structured at the vortex scale and almost compensates for horizontal advective heating in the cold cusps. In contrast to some previous studies, TIW-induced vertical advection is found to be negligible in the SST budget. Cooling by this term is only significant below the mixed layer. The effect of TIWs on the climatological heat budget is then investigated for the region bounded by 2°S–6°N, 160°–90°W, where instabilities are most active. TIW-induced horizontal advection leads to a warming of 0.84°C month?1, which is of the same order as the 0.77°C month?1 warming effect of atmospheric fluxes, while the mean currents and vertical mixing cool the upper ocean by ?0.59°C month?1 and ?1.06°C month?1, respectively. The cooling effect of TIW-induced vertical advection is also negligible in the long-term surface layer heat budget and only becomes significant below the mixed layer. The results above, and in particular the absence of cancellation between horizontal and vertical TIW-induced eddy advection, are robust in three other sensitivity experiments involving different mixing parameterizations and increased vertical resolution.<br/
Effects of endothelin-1 on fibroblasts from type 2 diabetic patients: Possible role in wound healing and tissue repair
No full textEndothelin-1 (ET-1) promotes the contractile ability of fibroblasts, essential for wound closure and reconstitution of the dermis. Wound healing is impaired in type 2 diabetic patients (D). We compared the effect of ET-1 on proliferative transforming growth factor (TGFbeta(1)) expression, fibronectin and laminin release), differentiative [alpha-smooth muscle actin (alpha-SMA) expression] and inflammatory [monocyte chemo-attractant protein (MCP-1) and interleukin-6 (IL-6) expression] responses in skin fibroblasts of healthy subjects (C) and D, testing the relative role of ET(A) and ET(B) receptors in mediating these responses. ET-1 did not influence TGFbeta(1), fibronectin or laminin production. alpha-SMA was more abundant and more stimulated in D, as well as MCP-1 and IL-6 expression and release. These effects were prevented by BMS-182874, selective antagonist of ET(A), more abundant than ET(B) in both cell strains and whose expression rose more in D than C upon stimulation with ET-1. This peculiar pattern of responses to ET-1, presumably acquired during the chronic in vivo exposure to hyperglycemia along the natural history of the disease, may partially explain the increased susceptibility of D to chronic ulcerations
Water-mass transformations in a neutral density framework and the key role of light penetration
No full textA new formulation is proposed for the evaluation of the dianeutral transport in the ocean. The method represents an extension of the classical diagnostic approach for estimating the water-mass formation from the buoyancy balance. The inclusion of internal sources such as the penetrative solar shortwave radiation (i.e., depth-dependent heat transfer) in the estimate of surface buoyancy fluxes has a significant impact in several oceanic regions, and the former simplified formulation can lead to a 100% error in the estimate of water-mass formation due to surface buoyancy fluxes. Furthermore, internal mixing can also be overestimated in inversions of in situ data when the shortwave radiation is not allowed to be penetrative.The method examines the evolution equation of neutral density via the tendencies of potential temperature and salinity. The neutral density framework does not require the choice of a reference pressure and thus, unlike previous approaches that consider potential density, it is well suited for examining the whole open-ocean water column.The methodology is easy to implement, particularly for ocean numerical models. The authors present here its application to a long simulation made with an ice–ocean global model, which allowed the method to be validated.<br/
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Understanding 1968: the case of Brest
No full textThis article examines the dominance of Paris in how May '68 has been portrayed over the years. It will be argued, through a case-study of the revolt in the Breton city of Brest, that the Paris-centred approach is one that belies the true nationwide aspect of May/June 1968. As one of a range of characteristics, the concentration on the Latin Quarter has helped mould what Kristin Ross has described as the 'official history' of 1968. An examination of how the events were played out within different regional contexts would go a long way towards helping overcome the shortcomings of the increasingly narrow portrayal that has come to dominate the stereotypical image of 1968
Effect of statins on soluble CD40 ligand in hypercholesterolemic Type 2 diabetic patients
No full textHypercholesterolemia and Type 2 diabetes are well-recognized risk factors for cardiovascular disease, promoted by a condition of subclinical inflammation and a hypercoagulable state. Soluble CD40 ligand (sCD40L), a marker of vascular inflammation, seems to predict vascular damage in patients with Type 2 diabetes. Beside the lipid-lowering effect, statins seem to slow the progression of atherosclerosis through a series of anti-inflammatory effects, including a reduction of sCD40L levels. This study compared the effect of a short-term (12 weeks) treatment with rosuvastatin or simvastatin on some markers of inflammation in 36 patients with Type 2 diabetes and moderate hypercholesterolemia. As expected, both drugs significantly modified lipid profile; moreover, rosuvastatin and simvastatin were both able to significantly reduce albumin excretion rate in these patients, without affecting urinary N-acetyl-beta-D-glucosaminidase. Serum homocysteine was not influenced by the treatment, as interleukin-6 levels, while C reactive protein diminished; moreover, rosuvastatin, but not simvastatin, was able to significantly reduce sCD40L. The only clinical parameter related with the variations in sCD40L was systolic blood pressure. In hypercholesterolemic Type 2 diabetic patients, sCD40L, a factor playing a pivotal role in the pathogenesis of atherosclerosis and associated with more rupture-prone lesions, is reduced by short-term treatment with rosuvastatin
Effect of statins on soluble CD40 liqand in hypercholesterolemic type 2 diabetic patients
No full textHypercholesterolemia and Type 2 diabetes are well-recognized risk factors for cardiovascular disease, promoted by a condition of subclinical inflammation and a hypercoagulable state. Soluble CD40 ligand (sCD40L), a marker of vascular inflammation, seems to predict vascular damage in patients with Type 2 diabetes. Beside the lipid-lowering effect, statins seem to slow the progression of atherosclerosis through a series of antiinflammatory effects, including a reduction of sCD40L levels. This study compared the effect of a short-term (12 weeks) treatment with rosuvastatin or simvastatin on some markers of inflammation in 36 patients with Type 2 diabetes and moderate hypercholesterolemia. As expected, both drugs significantly modified lipid profile; moreover, rosuvastatin and simvastatin were both able to significantly reduce albumin excretion rate in these patients, without affecting urinary N-acetyl-beta-D-glucosaminidase. Serum homocysteine was not influenced by the treatment, as interleukin-6 levels, while C reactive protein diminished; moreover, rosuvastatin, but not simvastatin, was able to significantly reduce sCD40L. The only clinical parameter related with the variations in sCD40L was systolic blood pressure. In hypercholesterolemic Type 2 diabetic patients, sCD40L, a factor playing a pivotal role in the pathogenesis of atherosclerosis and associated with more rupture-prone lesions, is reduced by short-term treatment with rosuvastatin. ©2008, Editrice Kurtis
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