170,198 research outputs found
Reply to "Comment on 'Piezonuclear decay of thorium' [Phys. Lett. A 373 (2009) 1956]" [Phys. Lett. A 373 (2009) 3795]
No full textIn a paper appearing in this issue of Physics Letters A, Ericsson et al. raise some critical comments on the experiment [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] we carried out by cavitating a solution of thorium-228, which evidenced its anomalous decay behaviour, thus confirming the results previously obtained by Urutskoev et al. by explosion of titanium foils in solutions. In this Letter, we reply to these comments. In our opinion, the main shortcomings of the criticism by the Swedish authors are due to their omitting of inserting our experiment in the wider research stream of piezonuclear reactions, and to the statistical analysis they used, which does not comply with the rules generally accepted for samples with small numbers. However, apart from any possible theoretical speculation, there is the basic fact that two different experiments (ours and that by Urutskoev et al.), carried out independently and by different means, highlight an analogous anomaly in the decay of thorium subjected to pressure waves. Such a convergence of results shows that it is worth to further carry on experimental investigations, in order to get either a confirmation or a disproof of the induced-pressure anomalous behaviour of radioactive nuclides even different from thorium. (C) 2009 Elsevier B.V. All rights reserved
Influence of Ca2+ and 6-benzyladenine on chestnut (Castanea sativa Mill.) in vitro shoot-tip necrosis
No full textShoot apex necrosis affects in vitro chestnut cultures particularly during the rooting stage. Lack of cytokinins or Ca2+ deficiency in the culture medium have been reported to be responsible for occurrence of tip necrosis. In the present research the effects of three Ca2+ levels (3, 9 and 18 mmol l-1) were tested on C. sativa 'Garrone rosso' and 'Clone 46' shoots treated for rooting. Tissue Ca2+ content of the apical, middle and basal portion of both brown and healthy shoots was determined. In a second trial the tip necrosis related effect of the local (tip) application of CaCl2 (3 mmol l-1), BA (5 μmol l-1) and CaCl2 + BA (3 mmol l-1 and 5 μmol l-1) was tested on Clone 46 shoots, during rooting. With regard to Ca2+ concentration in the rooting medium, no significant difference could be detected from the three tested Ca2+ levels on tip necrosis but the highest one caused a drop in rooting ability. Regardless of Ca2+ concentration, Garrone rosso showed a lower percentage of the disorder and a higher affinity for calcium in terms both of uptake and ion translocation. The data of the second trial showed that the local application of 5 μmol l-1 BA completely eliminated tip necrosis while the application of CaCl2 + BA delayed the appearance of the disorder. Apex calcium content of shoots treated locally revealed that the most the healthy tissue contained higher calcium levels than the necrotic one. BA treated shoots contained the lowest ion levels, independently from their status
Water status, growth and calcium nutrition of apple trees in relation of bitter pit
No full textThree different water status conditions (full watered, mild deficit and high deficit) were applied to cultivar 'Granny Smith' apple trees growing in pots during two periods of 4 weeks (last phase of fruit growth by cell division and middle phase of fruit growth by cell enlargement). In the first period, water deficit strongly reduced shoot, leaf and fruit growth, increased the calcium content in leaves and reduced the appearance of bitter pit in fruits. When applied in the second period, water deficit reduced leaf weight and fruit growth, increased the calcium content in leaves and reduced the appearance of bitter pit in fruits. Leaf sap osmolarity was lowered by the water deficit condition. These results are discussed with regard to patterns of diurnal water status in the differently watered trees
Biochemical parameters for the evaluation of different peach flesh types
No full textThe features of quality in peach fruits include both organoleptic and postharvest traits. Flesh texture is one of the main peach quality parameters and different flesh phenotypes have been described: the melting (M), with a range of firmness from very low to very firm (MVF), the stony hard (SH), that has long-lasting, very firm flesh and the non melting (NM), that produces a rubbery texture that is distinct from melting. Fruits from twenty four cultivars or selections with the above flesh types were assessed for ethylene prodn. rate, total, sol., and insol. pectins, and calcium content in the cell wall. SH fruits showed no or a very low ethylene prodn., always less than 10 mL/kg h, while the M and NM flesh produced more than 10 mL/kg h and the latter often more than 25 mL/kg h. Ethylene level seemed a useful index also because of its rather simple and fast measurement. Calcium and pectin content was also different, particularly the ion bound to the insol. pectin fraction. SH showed a high pectin content with a low sol./insol. pectin ratio, while the NM had the highest total pectin and high calcium content in the cell walls. MVF presented a low pectin content but with a low sol./insol. pectin ratio and the highest amt. of total and insol. pectin-bound calcium. [on SciFinder (R)
Motivazione, apprendimento e valutazione nella scuola secondaria di II grado : il caso delle olimpiadi nazionali di statistica
No full textit is well known from literature on teaching statistics that learning of this discipline gives better results if the students are involved in empirical problems. This paper describes the results of the National Olympic Games of Statistics at High School. The aim of this project is to encourage and stimulate students to develop statistical reasoning
The reaction e(+)e(-) gamma pi(0) gamma nu(nu)over-bar as a probe of neutrino mass
No full textThe reaction e(+)e(-) --> gamma pi(0) --> gamma nu is considered. It is shown that this The reaction ef reaction possesses a clear signature, producing in the resonance region practically monochromatic photons, which can easily be distinguished from background bremsstrahlung photons. Since the cross section of the reaction is proportional to the square of the neutrino mass, such a reaction can be used as a probe for neutrino mass. (C) 1997 American Institute of Physics
Effects of postharvest treatments and storage conditions on chestnut quality
No full textInterest in chestnut is increasing because of both its healthy nutritional contents and curiosity about ancient traditional foods. Fruit is grown either for fresh market or for production of special and typical foodstuff. The nut loses viability rapidly after harvest due to fruit rots and insects and several storage methods have previously been applied to prolong its postharvest life. The present work considers two local chestnut cultivars (Catot and Platella) from Valle Camonica (Brescia, Northern Italy), grown at 900 m a.s.l. Nuts were treated (or not) with traditional curing (nine days submerged in water), hot (51°C) water for 45 min, NaHCO3 1% and stored for 60 and 105 days in cold room (1°C) equipped with two different Controlled Atmosphere conditions (CA1: 2.5 % CO2, 1.5 % O2; CA2: 20% CO 2, 2% O2). At harvest and following storage, fruit of cv Platella from control, cured and CA2 treatments, were peeled, sterilized, cut into halves, plated in Petri dishes and incubated at 24°C for 21 days to assess fungal contamination. Curing, heat treatment and CA2 were very effective in controlling fruit rots until December (60 days) then their effect decreased. CA2 maintained the best quality of fruits in term of freshness, taste and flavor. For example, in mid February (105 days) the chestnuts looked as fresh and bright as just picked nuts. Cured and heat treated fruits were respectively a little or very dry and NaHCO3 treatment had no effect in controlling fruit rots. The treatments seemed to exhibit a selective effect on diverse fungal contaminants; i.e. curing was efficacious in reducing contamination due to all fungi except from Penicillium spp., and CA gave excellent results, but it was ineffective in controlling Aspergillus niger. Apart from NaHCO3, the treatments were effective in controlling insect development
Non-invariant ground states, thermal average, and generalized fermionic statistics
No full textWe present an approach to generalized fermionic statistics which relates the existence of a generalized statistical behaviour to non-invariant ground states. Considering the thermal average of an operator generalization of the Heisenberg algebra, we get an occupation number which depends on the degree of mixing between symmetric and antisymmetric sectors of the ground state. A natural prescription is given for the construction of a supersymmetric statistics. We also show that the structure of the vacuum, and therefore the statistical behaviour of the system, can be accounted for in terms of a second-order phase transition. (C) 1999 Published by Elsevier Science B.V. All rights reserved
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