Observation of an incoherent thermally activated proton hopping process in calix-[4]-arene by means of anelastic spectroscopy

The anelastic spectrum of calix[4]arene was measured at two different vibrational frequencies. Three thermally activated peaks were detected. The lowest temperature peak can be described considering a continous distribution function of activation energies for the relaxation. This anelastic peak can be ascribed to a thermally activated hopping process of H atoms of the OH groups, corresponding to a flip-flop of the OH bond. From the results of the present study, it seems that anelastic spectroscopy is a good experimental technique to study atomic motion inside molecules at a mesoscopic (few molecules) level.Comment: 5 pages, 4 figures, submitted to Phys. Rev.

Communications Biophysics

Contains research objectives and reports on one research project.U.S. Air Force under Contract AF19(604)-411

Coordination between plant and apex development in Hordeum vulgare ssp. distichum

Developmental scales for cereals describe apex and plant morphology separately. In order to link crucial steps of internal and external development, in three varieties of Hordeum vulgare spp. distichum L., sown in autumn and in spring, we recorded plant, leaf and apex stage, following the scales of Zadoks, Haun, and Banerjee and Wienhues, the number of primordia, culm and spike length, and the final number of leaves and spikelets. Primordia initiation was coordinated with leaf appearance and the relative rate was constant for the initiation of productive primordia. The maximum number of primordia was achieved just before the first node became detectable, but development was completed only by those initiated before floret differentiation and internode distension started. The first spikelet was initiated when the third leaf tip became visible, and the last one when plants were at the pseudo stem erection stage and five leaves had still to appear

Optics Measurements and Matching of TT2-TT10 Line for Injection of the LHC Beam in the SPS

A well matched injection in the SPS is very important for preserving the emittance of the LHC beam. The paper presents the algorithms used for the analysis and the results of the optics measurements done in the transfer line TT2-TT10 and in the SPS. The dispersion is computed by varying the beam momentum and recording the offsets at the BPMs, while the Twiss parameters and emittance measurements in TT2-TT10 are performed with beam profile monitors equipped with OTR screens. These results are completed by those obtained with a matching monitor installed in the SPS as a prototype for the LHC. This device makes use of an OTR screen and a fast acquisition system, to get the turn by turn beam profiles right at injection in the ring, from which the beam mismatch is computed and compared with the results obtained in the line. Finally, on the basis of such measurements, a betatron and dispersion matching of TT2-TT10 for injection in the SPS has been performed and successfully put in operation

Post-anthesis accumulation and remobilization of dry matter, nitrogen and phosphorus in durum wheat as affected by soil type

The objective of the research was to quantify the changes in the accumulation of dry matter and N and P content of four durum wheat (Triticum durum Desf.) varieties grown on two soil types (sandy-loam and clay-loam), differing for texture, nitrogen content and water holding capacity. Plants were grown in containers and were rainfed until anthesis; irrigation was performed during grain filling to avoid water stress. The difference in total vegetative weight and nitrogen and phosphorus content of plants between anthesis and maturity was used to indirectly estimate the relative contribution of pre-anthesis assimilation and remobilization to grain yield. The behaviour of the four varieties was similar as they ranked in the same order for pre-anthesis and post-anthesis dry matter accumulation and grain yield and differences in soil characteristics induced similar changes in dry matter, N and P accumulation and remobilization. Soil type greatly affected the patterns of dry matter, N and P accumulation and remobilization. Plants grown on clay-loam soil had higher dry weight and N and P content both at anthesis and at maturity and higher grain yield at maturity, compared to plants grown on sandy-loam soil and the remobilization of dry matter, N and P were 75, 140 and 55% higher. Most of the grain carbohydrates originated from photosynthates produced during grain fill, as the contribution of remobilization of dry matter to grain yield did not reach 30%, while most of the grain N and P originated from the remobilization of N and P accumulated prior to anthesis as remobilization of N accounted for 73–82% of grain N content and remobilization of P accounted for 56–63% of grain P content