HIGH TEMPERATURE EXPANSION OF STRING FREE ENERGY IN HYPERBOLIC SPACE

The high temperature behaviour of the open bosonic string free energy in the space $S^1 \otimes H^N$ with vanishingly small curvature is investigated. The leading term of the high temperature expansion of the one-loop free energy, near the Hagedorn instability, is obtained. The problem of infrared regularization of thermodynamical quantities is pointed out. For minimally coupling quantum fields related to the normal modes of strings, the results are similar to the ones valid for Rindler space. In the lower mass string states regime a connection with the quantum corrections to the black hole entropy is outlined.Comment: 7 pages, latex file, no figures

A Finite-Temperature Periodic Structure in (SUPER)STRING Theory

Using a Laurent series representation for the (super)string one-loop free energy, an explicit form for the analytic continuation of the Laurent series beyond the critical (Hagedorn) temperature is obtained. As an additional result, a periodic structure is found in (super)string thermodynamics. A brief physical discussion about the origin and meaning of such structure is carried out.Comment: 9 pages, LaTeX file, UB-ECM-PF 92/3

Influence of cold storage time on the softening prediction in Spring Bright nectarines

With Time-resolved Reflectance Spectroscopy (TRS) the maturity of nectarines at harvest can be assessed by measuring the absorption coefficient at 670 nm (µa 670) in the fruit flesh. A kinetic model has been developed linking the optical properties as measured by TRS with the models of µa 670 and firmness decay in shelf-life at 20°C, making the prediction of the softening time for individual fruit possible. In order to study the influence of cold storage time prior to shelf life on the softening prediction, 540 (year 2003) and 870 (year 2004) ‘Spring Bright’ nectarines were measured at harvest with TRS; then fruit were put in shelf life after various periods of cold storage at 0°C (4 and 10 d, year 2003; 6, 13 and 20 days, year 2004). During the 5-day period of shelf life at 20°C, fruit were analysed for firmness by pressure test after 30, 48, 54, 72, 78, 96, 102 and 120h in 2003 and after 36, 43, 62, 87, 108 and 135h in 2004. For each year and cold storage time, the parameters of the logistic model of softening as a function of µa 670 at harvest were computed. The cold storage up to 13 days did not significantly influence the estimates of the softening rate constant (kf), of the maximum firmness at minus infinite time (Fmax) and of parameter alpha (a) in both years, whereas parameter beta (ß) in 2003 significantly decreased from -1.867 at day 4 to -2.237 at day 10. The further 7 days of cold storage in 2004 significantly affected kf, which decreased from 0.00084 at days 6 and 13 to 0.00069 at day 20, and ß which increased from -2.395 at day 6 to -2.053 at day 20. Our results indicate that the cold storage time significantly influences the softening prediction of nectarines as the longer the cold storage, the lower the softening rat

Asymptotic Level State Density for Parabosonic Strings

Making use of some results concerning the theory of partitions, relevant in number theory, the complete asymptotic behavior, for large $n$, of the level density of states for a parabosonic string is derived. It is also pointed out the similarity between parabosonic strings and membranes.Comment: 9 pages , LaTe

Ethylene production and quality in 1-Methylcyclopropene treated 'Abbé Fètel'pears after storage in Dynamically Controlled Atmosphere

This research studies the ethylene production rate (EP) and quality in 1-MCP treated ‘Abbé Fètel’ pears after storage in DCA compared to NA and CA. 1-MCP treated (300 ppb) and control fruit were stored at -0.5°C in NA, CA (2 kPa O2 + 0.7 kPa CO2) and DCA (0.7 kPa O2 + 0.3 kPa CO2). After 4 and 6 months storage, fruit were held up to 7 d at 20°C. Skin colour, firmness and EP were measured during shelf life and the incidence of disorders after 7 d. 1-MCP treatment drastically reduced EP, which began to recover after 7 d at 20°C, except for DCA stored pears. In control fruit, NA stored pears showed the highest EP. 1-MCP treated fruit were the greenest at the end of shelf-life, especially after CA and DCA. Control fruit stored in DCA and in CA were greener than NA both at 1 d and 7 d of shelf life. Pears treated with 1-MCP did not soften during shelf life, while in control fruit firmness decreased from about 40 N to about 15-20 N, whatever the storage atmosphere. 1-MCP treatment prevented soft and superficial scald and internal breakdown, independently of storage atmosphere. DCA prevented superficial scald in control fruit, while it increased internal browning and breakdown in control and 1-MCP treated pears. No differences were found for soft scald incidence between control DCA and CA stored fruit. The highest percentage of sound fruit was found in NA stored 1-MCP treated pears, and the lowest in control fruit stored in DC