3,426 research outputs found
Participatory design, beyond the local
This workshop aims at stimulating and opening a debate around the capacity of Participatory Design (PD) and other co-design approaches to deliver outcomes and methodologies that can have an impact and value for reuse well beyond the local context in which they were originally developed. This will be achieved by stimulating the submission of position papers by researchers from the PD community and beyond.These papers will be discussed during the workshop in order to identify challenges, obstacles but also potentials for scaling up PD processes and results from the local to the global.</p
Footprints of element mobility during metasomatism linked to a late Miocene peraluminous granite intruding a carbonate host (Campiglia Marittima, Tuscany)
The Campiglia Marittima magmatic-hydrothermal system includes a peraluminous granite, its carbonatic host, and skarn. The system evolved generating a time-transgressive exchange of major and trace elements between granite, metasomatic fluids, and host rock. The process resulted in partial metasomatic replacement of the granite and severe replacement of the carbonate host rocks. The fluid activity started during a late-magmatic stage, followed by a potassicâcalcic metasomatism, ending with a lower temperature acidic metasomatism. During the late-magmatic stage, B-rich residual fluids led to the formation of disseminated tourmalineâquartz orbicules. High-temperature metasomatic fluids generated a pervasive potassicâcalcic metasomatism of the granite, with replacement of plagioclase, biotite, ilmenite, and apatite by K-feldspar, phlogopiteâchloriteâtitanite, titaniteârutile, and significant mobilization of Fe, Na, P, Ti, and minor HFSE/REE. The metasomatized granite is enriched in Mg, K, Rb, Ba, and Sr, and depleted in Fe and Na. Ca metasomatism is characterized by crystallization of a variety of calc-silicates, focusing along joints into the granite (endoskarn) and at the marble/pluton contact (exoskarn), and exchange of HFSE and LREE with hydrothermal fluids. Upon cooling, fluids became more acidic and fluorine activity increased, with widespread crystallization of fluorite from disequilibrium of former calc-silicates. At the pluton-host boundary, fluids were accumulated, and pH buffered to low values as temperature decreased, leading to the formation of a metasomatic front triggering the increasing mobilization of REE and HFSE and the late crystallization of REEâHFSE minerals
Ρ1-Allylpalladium complexes with a tridentate PNP ligand with different phosphino groups
The iminodiphosphine 2-(PPh2)C6H4-1-CHvNC6H4-2-(PPh2) (PâNâPâ˛) is used for the preparation of the
complexes [Pd(Ρ1-CHR1âCHvCR2R3)(PâNâPâ˛)]BF4 [R1 = R2 = R3 = H: (1); R1 = R2 = Ph,
R3 = H: (2); R1 = R3 = H, R2 = Ph: (3); R1 = H, R2 = R3 = Me: (4)]. The PâNâPⲠtridentate coordination
and the Ρ1-allyl bonding mode in the solid are confirmed by the X-ray structural analysis of 1. In solution,
the complexes 1 and 2 undergo an Ρ1âΡ3âΡ1 rearrangement at 298 K interconverting the bonding site of
the allyl group. A five-coordinate structure with the phosphine ligands in the axial position is proposed
for the Ρ3-allyl intermediate. For the dynamic process, a ÎGâ value of 53.8 kJ molâ1 is obtained from
1H NMR data of 2. In 3 and 4, the allyl ligand is rigidly bound to the metal through the less substituted
terminus, in line with the higher free energy content of the corresponding isomers: [Pd(Ρ1-CHPhâ
CHvCH2)(PâNâPâ˛)]+ +48.78 kJ molâ1; [Pd(Ρ1-CMe2âCHvCH2)(PâNâPâ˛)]+ +69.35 kJ molâ1. The
complexes react with secondary amines in the presence of fumaronitrile at different rates yielding
allylamines and the palladium(0) derivative [Pd(Ρ2-fn)(PâNâPâ˛)] (5). On the basis of charge distribution
on the allylic carbon atoms and of steric factors, the difference in rate and the regioselectivity in the
amination of 1â3 are better rationalized by a mechanism with nucleophilic attack at the Ρ3-intermediate
rather than by an SN2 mechanism with nucleophilic attack at the PdâCHR1 carbon atom. The high
regioselectivity in the reaction of 4 with piperidine implies an SN2Ⲡmechanism with nucleophilic attack at
the CMe2 allyl carbon. A dynamic process occurs also for the 18-electron complex 5 consisting in a
dissociationâassociation equilibrium of the olefin
The Potential Role of Mother-in-Law in Prevention of Mother-to-Child Transmission of HIV: A Mixed Methods Study from the Kilimanjaro Region, Northern Tanzania.
In the Kilimanjaro region the mother-in-law has traditionally had an important role in matters related to reproduction and childcare. The aim of this study was to explore the role of the mothers-in-law in prevention of mother-to-child transmission (PMTCT) service utilization and adherence to infant feeding guidelines. The study was conducted during 2007-2008 in rural and urban areas of Moshi district in the Kilimanjaro region of Tanzania. Mixed methods were used and included focus group discussions with mothers-in-law, mothers and fathers; in-depth interviews with mothers-in-law, mothers, fathers and HIV-infected mothers, and a survey of 446 mothers bringing their four-week-old infants for immunisation at five reproductive and child health clinics. The study demonstrated that the mother-in-law saw herself as responsible for family health issues in general and child care in particular. However she received limited trust, and couples, in particular couples living in urban areas, tended to exclude her from decisions related to childbearing and infant feeding. Mothers-in-law expected their daughters-in-law to breastfeed in a customary manner and were generally negative towards the infant feeding methods recommended for HIV-infected mothers; exclusive replacement feeding and exclusive breastfeeding. Decreasing influence of the mother-in-law and increasing prominence of the conjugal couples in issues related to reproduction and child care, reinforce the importance of continued efforts to include male partners in the PMTCT programme. The potential for involving mothers-in-law in the infant feeding component, where she still has influence in some areas, should be further explored
Catadioptric stereo-vision system using a spherical mirror
Abstract In the computer vision field, the reconstruction of target surfaces is usually achieved by using 3D optical scanners assembled integrating digital cameras and light emitters. However, these solutions are limited by the low field of view, which requires multiple acquisition from different views to reconstruct complex free-form geometries. The combination of mirrors and lenses (catadioptric systems) can be adopted to overcome this issue. In this work, a stereo catadioptric optical scanner has been developed by assembling two digital cameras, a spherical mirror and a multimedia white light projector. The adopted configuration defines a non-single viewpoint system, thus a non-central catadioptric camera model has been developed. An analytical solution to compute the projection of a scene point onto the image plane (forward projection) and vice-versa (backward projection) is presented. The proposed optical setup allows omnidirectional stereo vision thus allowing the reconstruction of target surfaces with a single acquisition. Preliminary results, obtained measuring a hollow specimen, demonstrated the effectiveness of the described approach
Morfologia e anatomia do fruto em desenvolvimento de Matisia cordata (Humb. & Bonpl. - Bombacaceae).
Strong Rayleigh-Darcy convection regime in three-dimensional porous media
We perform large-scale numerical simulations to study Rayleigh-Darcy convection in three-dimensional fluid-saturated porous media up to Rayleigh-Darcy number. At these large values of, the flow is dominated by large columnar structures - called megaplumes - which span the entire height of the domain. Near the boundaries, the flow is hierarchically organized, with fine-scale structures interacting and nesting to form larger-scale structures called supercells. We observe that the correlation between the flow structure in the core of the domain and at the boundaries decreases only slightly for increasing, and remains rather high even at the largest considered here. This confirms that supercells are the boundary footprint of megaplumes dominating the core of the domain. In agreement with available literature predictions, we show that the thickness of the thermal boundary layer scales very well with the Nusselt number as. Measurements of the mean wavenumber - inverse of the mean length scale - in the core of the flow support the scaling, in very good agreement with theoretical and numerical predictions. Interestingly, the behaviour of the mean wavenumber near the boundaries scales as, which is distinguishably different from the presumed linear behaviour. We hypothesize that a linear behaviour can only be observed in the ultimate regime, which we argue to set in only at in excess of, whereas a sublinear behaviour is recovered at more modest. The present results are expected to help the development of long desired reliable models to predict the large- and fine-scale structure of Rayleigh-Darcy convection in the high- regime typically encountered in geophysical processes, such as for instance in geological carbon dioxide sequestration
Towards the ultimate regime in Rayleigh-Darcy convection
Numerical simulations are used to probe Rayleigh-Darcy convection in fluid-saturated porous media towards the ultimate regime. The present three-dimensional dataset, up to Rayleigh-Darcy number, suggests that the appropriate scaling of the Nusselt number is, fitting the computed data for. Extrapolation of current predictions to the ultimate linear regime yields the asymptotic law, about less than indicated in previous studies. Upon examination of the flow structures near the boundaries, we confirm previous indications of small flow cells hierarchically nesting into supercells, and we show evidence that the supercells at the boundary are the footprints of the megaplumes that dominate the interior part of the flow. The present findings pave the way for more accurate modelling of geophysical systems, with special reference to geological sequestration
Long non-axisymmetric fibres in turbulent channel flow
In this work, we investigate the dynamics of long non-axisymmetric fibres in turbulent channel flow. The experimental facility is the TU Wien Turbulent Water Channel, consisting of a closed water channel (aspect ratio of 10), and the experiments are performed at a shear Reynolds number of 360. Fibres are neutrally buoyant rods that are curved and characterised by a length-to-diameter ratio of 120. Illumination is provided by a laser sheet and the motion of fibres is recorded by four high-speed cameras in a fully developed flow section. We apply multiplicative algebraic reconstruction techniques to the recorded images from four high-speed cameras to identify the three-dimensional location, shape and orientation of the fibres. The fibres are also tracked in time to obtain their three-dimensional vectors of velocity and rotation rate. We investigate the behaviour of the fibres, from the near-wall region to the channel centre, and we produce original statistics on the effect of curvature of the fibres on their orientation and rotation rate. Specifically, we measured the orientation and rotation rate of the fibres, and we can confirm that in the centre, the most homogeneous part of the channel, statistics, although influenced by the curvature, bear similarities to those obtained in previous investigations in homogeneous isotropic turbulence. In addition, we have been able to compare the tumbling rate of our long non-axisymmetric fibres with previous solutions for curved ellipsoids in simple shear flow
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