Project Citizen CaseBase: Strengthening Youth Voices in an Open-Source Democracy

The Center for Civic Education seeks a Level II Digital Humanities Start-Up Grant to develop a prototype of a free online multimedia dashboard and database that will enable more than 1.5 million young people in more than 65 countries participating in the Center’s Project Citizen program to share their public policy initiatives with audiences beyond their immediate communities. It will allow middle and high school students to work easily with peers in their school and other schools as well as scholars and public officials in their communities and in other countries, using online interaction and digital media to increase the impact of their joint endeavors. The online database of student public policy projects will grow with each posting and will be searchable by topic, location, and other criteria. Integrated social networking tools will allow students to share ideas directly with other students across the nation and around the world

a comparison of state based peridynamics and solid mesh to sph conversion techniques to reproduce fragmentation of a ceramic tile subject to ballistic impact

Abstract This paper presents a comparison of two present meshfree approaches for modelling brittle material in case of ballistic impact, where extensive cracking and fragmentation is present. These phenomena are very unfeasible to simulate with a standard Lagrangian technique thus alternative methods have been considered in the last years. A comparison between two methods is the main aim of the present article. Smoothed Particle Hydrodynamics (SPH) is an almost consolidated method that exploit the description of a continuum by means of discrete elements whose properties are "smoothed" by a Kernel Function. In this paper a procedure that exploits the transition from finite elements (FE) to SPH particles, following the onset of an erosion criterion is used. This approach and its results are then compared to the recent state-based Peridynamics. Peridynamics method is based on integral equation and allow a direct application to discontinuities and fractures. The results from both methods are critically compared with experimental data and show that the damage morphology is reproduced similarly by both approaches; however less computation efforts are required when peridynamics are used

Forage and grain yield of common buckwheat in Mediterranean conditions: Response to sowing time and irrigation

With the view to extending the cultivation of common buckwheat to Mediterranean environments, we investigated the responses of two varieties to three sowing times, early spring, late spring and late summer, in rainfed and irrigated conditions. Plants were harvested at two ripening stages for forage production and at maturity for grain yield. The crop cycle lasted 82-88 days independent of sowing time, whereas the thermal time was ∼1000 degree-days in early spring and late summer sowings, and 1200 degree-days when sown in late spring. Forage yield increased up to 75% between ripening stages. Early spring was the best sowing time for forage (4tha-1 dry weight) and grain yield (2tha-1 dry weight) in rainfed conditions. Late spring sowings give the highest forage yield when irrigated (6tha-1 dry weight), but were not suitable for producing grain, for the adverse effect of high summer temperatures on seed set and seed filling. Late summer sowings produced acceptable grain yield (1.5tha-1 dry weight), whereas short days and low temperatures limited forage production. Thus, in Mediterranean environments, buckwheat could be profitably introduced as a minor summer crop, sown in early spring for grain production and in late spring for forage production

A growth scale for the phasic development of common buckwheat

Growth scales give a standardized definition of crop development and increase the understanding among researchers and growers. In this research we defined a growth scale for the phasic development of common buckwheat that was mainly based on a sequence of easily recognizable changes occurring on the first and the terminal clusters of inflorescences formed on the main stem. Observations were carried out on plants grown in two years throughout spring. In an attempt to uniform the duration of phasic development across sowing dates, the length of phases and sub-phases was calculated in days and in thermal time using nine combinations of cardinal temperatures. A sequence of stages and various patterns of coordinated development were maintained throughout all sowings and years. Specifically, (1) the first inflorescence became visible after three true leaves had fully expanded on the main stem; (2) flowering reached the terminal inflorescence cluster before full-sized green fruits became visible in the first inflorescence, and (3) fruit ripening in the whole plant ended within two weeks of the end of ripening in the oldest inflorescence. Plant size was increased with the delay of sowing, and the length of the growth cycle was by approximately 400°Cd longer when plants experienced a day length longer than 15 h. This changed the correspondence between flowering and ripening stages, so that full flowering was associated with the development of green fruits in the first inflorescence when the cycle was short, but with their development in the terminal cluster when it was long. Trends in grain yield did not correspond to those in plant size and phase length. We are confident that this growth scale will be a valuable tool for following the progress of buckwheat development and to predict growth patterns and harvest time in response to temperature and photoperiod

Forage potential of winter cereal/legume intercrops in organic farming

This research was performed to assess the potential of cereal/legume intercropping to enhance forage yield and quality when compared with cereal sole crops under the constrains imposed by UE organic farming regulations. Sole crops (SC) and intercrops (IC) of two winter cereals, barley (Hordeum vulgare L.) and durum wheat (Triticum durum Desf.), and two legumes, white lupin (Lupinus albus L.) and common vetch (Vicia sativa L.), were evaluated at two harvest times for dry matter yield (DMY), crude protein concentration (CPC), and nitrogen yield (NY). Yield values and dry matter concentration (DMC) were generally higher when cereals were at the hard dough compared to the late milk stage. On average, intercropping increased forage yield by 72%, NY by 190%, and CPC by 40 g kg-1, compared to cereal sole crops, but the choice of legume species affected the yield advantage and the composition of forage. Land equivalent ratio (LER) of intercrops was always higher than 1, ranging from 1.39 to 1.61. Intercropping also enhanced weed suppression, compared to sole crop

Cadmium uptake and translocation in durum wheat varieties differing in grain-Cd accumulation

Wheat grain products are the primary source of dietary Cd-intake for humans. Since varieties differ markedly in grain-Cd accumulation, efforts are needed to find traits associated with low, or high, accumulation. Two durum wheat varieties, selected in a field screening as low (Creso) and high (Svevo) grain-Cd accumulating, were grown on soil spiked with 1.5, 3 and 4.5 mg Cd/kg. Growth patterns, Cd uptake and translocation were investigated at heading and maturity. Cadmium did not affect plant growth and grain yield, but grain-Cd concentration always exceeded the permissible limit of 0.2 mg Cd/kg, and was approximately double in Svevo than in Creso. At maturity, total Cd-uptake increased linearly with supply in Creso, from 13 to 23 μg/plant, and was approximately 18 μg/plant, irrespective of Cd level, in Svevo. Partitioning to shoot was higher in Svevo than in Creso, both at heading and maturity. We suggest that reduced plant height, high root to shoot biomass ratio during vegetative growth and elevated post-heading dry matter accumulation promoted Cd accumulation into grain. Since these traits are common to modern wheat varieties, risks of grain Cd-contamination can increase in the future