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Spectra of secondary particles in gamma-families, detected at the Pamirs level in X-ray emulsion chambers, are analyzed. This analysis showed that secondary particle spectra change their slope at the particle energy equal to the summary particle energy at which we select gamma-families. Above this bend the secondary particle slope is sensitive to the PCR spectrum slope and composition. The slopes of secondary particle spectra in the Experiment PAMIR are close to the slopes in the variants of the MC0 model, in which the fraction of primary protons is not less than 25% after the knee.

The response of the X-ray emulsion chamber (XREC) is analyzed. The code GEANT 3.21 has been adopted for simulating the measurement procedure in the PAMIR XREC experiment. The contribution of below threshold gamma-quanta, the mutual influence of neighboring electromagnetic cascades in gamma-families, identification against a background by Raleigh's criterion are taken into account. Our earlier publications overestimated the family energy by about ( 10 ÷ 20 )% and the real family angular distribution is less steeper than the measured one. Consequently, the gamma-family intensity should be reduced by 1.10 ÷ 1.15 times. It means, that the Pamir experiment estimate of the PCR proton fraction in the energy region 1 ÷ 100 PeV slowly decreases from 25% to 20%.

The mass composition of the primary cosmic rays (PCR) is deduced from the intensity and energy spectrum of γ -families recorded in X-ray emulsion chambers (XREC) at the Pamirs. The analysis is based on comparison of the experimental data with model calculation. The best fit is attained assuming that the proton fraction in the PCR gradually decreases from 25% at PCR energy E 0 = 10 15 eV to 15% at E 0 = 10 17 eV . The unusual phenomena (alignment effect and penetrating hadrons) are also discussed. Further experiments with XREC at the Tien Shan is in the progress.

Seven cellulase preparations from Penicillium and Trichoderma spp. were evaluated for their ability to hydrolyze the cellulose fraction of hardwoods (yellow poplar and red maple) pretreated by organosolv extraction, as well as model cellulosic substrates such as filter paper. There was no significant correlation among hydrolytic performance on pretreated hardwood, based on glucose release, and filter paper activity. However, performance on pretreated hardwood showed significant correlations to the levels of endogenous beta-glucosidase and xylanase activities in the cellulase preparation. Accordingly, differences in performance were reduced or eliminated following supplementation with a crude beta-glucosidase preparation containing both activities. These results complement a previous investigation using softwoods pretreated by either organosolv extraction or steam explosion. Cellulase preparations that performed best on hardwood also showed superior performance on the softwood substrates.

Experimental data obtained with X-ray emulsion chambers by the "Pamir" collaboration are compared with calculations using the code MC0 of the quark-gluon-string model. The best fit to the experimental data is attained assuming that the primary cosmic ray (PCR) mass composition in the PCR energy range 1015–1017 eV becomes slowly enriched with heavy nuclei, so that the proton fraction decreases from 33% at E 0 = 10 15 eV to 20% at E 0 = 10 17 eV . To bring model calculations in agreement with experimental data at PCR energy E 0 = 10 17 – 10 18 eV it is necessary to assume a rapid increase of the proton fraction in PCR composition and a possible change of slope exponent of the PCR energy integral spectrum from γ = 2.05 to γ = 1.65 .

Seven fungal cellulase preparations from Trichoderma and Penicillium spp. were evaluated for their ability to hydrolyze the cellulose component of lignocellulose samples prepared from softwoods by steam explosion or organosolv pretreatment. Hydrolysis was quantified using two indices: mean specific rate and specific conversion. The activities of the cellulase preparations on model cellulosic substrates (filter paper, carboxymethylcellulose and Avicel) were also determined, together with their β-glucosidase, xylanase, pectinase, galactomannanase and β-glucanase activities. The ability of a cellulase preparation to hydrolyze pretreated softwood showed little correlation with its activity on filter paper, carboxymethylcellulose and Avicel; however, there was a significant correlation with its level of endogenous β-glucosidase and xylanase activity. Differences in the performance of the various cellulase preparations were substantially reduced following supplementation with a commercial β-glucosidase preparation from Aspergillus niger. In addition to β-glucosidase, this preparation was shown to contain significant levels of endogenous xylanase activity. It appears that the levels of endogenous β-glucosidase and xylanase are important factors in determining the ability of a cellulase preparation to hydrolyze pretreated softwood and that deficiencies in the levels of both enzymes can be compensated by supplementation with corresponding activities present in the β-glucosidase preparation. Presumably, β-glucosidase improves cellulose hydrolysis by reducing end-product inhibition by cellobiose, while xylanase activity increases the accessibility of cellulose to cellulases.

A new complex installation ATHLET is now being built at Tien Shan near Almaty. Some problems of the planned cosmic ray studies are discussed.

Adjusted data on the fraction of protons in the mass composition of primary cosmic rays (PCRs) in the energy range of 1015–1017 eV are presented. Adjustments are made according to detailed calculations of the response of the X-ray emulsion chamber in the PAMIR experiment. It is demonstrated that the fraction of protons in a PCR is 16–18% for E0 ≈ 1015–1016 eV and does not change within the error for E0 ≈ 1016–1017 eV.

I. V. AMURINA,1 V. P. ANTONOVA,2 G. M. AUTOVA,3 M. K. BABAEV,4 A. S. BAYGUBEKOV,4 P. F. BEYL’,1 R. U. BEISEMBAEV,1 A. E. BODUNOV-SKVORTSOV,5 A. S. BORISOV,5 K. V. CHERDYNTSEVA,5 A. P. CHUBENKO,5 P. A. CHUBENKO,5 V. G. DENISOVA,5 V. I. DROBZHEV,2 E. N. GUDKOVA,5 A. V. GUREVICH,5 Z. M. GUSEVA,5 E. A. KANEVSKAYA,5 J. KEMPA,6 M. G. KOGAN,5 E. V. KOSTIN,5 O. N. KRYAKUNOVA,2 A. V. KRUGLOV,1 S. V. KRYUKOV,2 M. I. KRYLOWA,1 A. I. KUPCHISHIN,7 A. K. MANAGADZE,8 I. S. MART’YANOV,4 V. M. MAXIMENKO,5 K. M. MUKASHEV,3 R. A. MUKHAMEDSHIN,9 R. A. NAM,1 N. M. NESTEROVA,5 KH. NURITDINOV,10 V. V. OSKOMOV,7 V. P. PAVLYUCHENKO,5 V. V. PISCAL’,1 R. YU. POLYAKOV,1 V. S. PUCHKOV,5 S. E. PYATOVSKY,5 I. V. RAKOBOL’SKAYA,8 T. M. ROGANOVA,8 N. N. ROINISHVILI,11 V. A. RYABOV,5 N. O. SADUEV,7 T. KH. SADYKOV,4 S. B. SHAULOV,5 A. L. SHCHEPETOV,5 S. A. SLAVATINSKY,5 A. V. STEPANOV,1 L. G. SVESHNIKOVA,8 G. T. SHOIYNBAEVA,3 ZH. T. TOLEGEN,7 YU. N. VAVILOV,5 A. V. VARGASOV,5 N. G. VIL’DANOV,1 L. I. VIL’DANOVA,1 V. I. YAKOVLEV,5 T. S. YULDASHBAEV,10 N. N. ZASTROZHNOVA,4 G. T. ZATSEPIN9 and V. V. ZHUKOV1 1Tien Shan Mountain Scientific Station of LPI, Almaty, 480037 Kazakhstan 2Institute of Ionosphere, Ministry of Education and Science, Almaty, 480020 Kazakhstan 3Abai Almaty State University, Almaty, 480100 Kazakhstan 4Physical-Technical Institute of Academy of Sciences of Uzbekistan, Almaty, 700084 Kazakhstan 5P. N. Lebedev Physical Institute, Moscow, 119991 Russia 6Warsaw University of Technology, Warszawska Politechnika, Off-Campus, Plock, 09400 Poland 7Al-Faraby Kazakh National University, Ministry of Education and Science, Almaty, 480012 Kazakhstan 8D. V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, 119899 Russia 9Institute for Nuclear Research, Russian Academy of Sciences, Moscow, 117312 Russia 10Physical-Technical Institute of Academy of Sciences of Uzbekistan, Tashkent, 700084 Uzbekistan 11Institute of Physics Academy of Sciences of the Georgian Republic, Tbilisi, 380077 Georgia

The experimental spectrum of halo areas for gamma-families with Σ E γ ≥ 500 TeV is obtained and compared with simulations in quark-gluon string model. The comparison suggests a ∼ 2 times decrease of the proton fraction in primary cosmic ray (PCR) composition in the energy region 10 16 ÷ 10 17 eV. However at an energy above 10 17 eV, the experimental flux of halo events with area exceeding 300 ÷ 400 mm 2 is 5 ÷ 10 times larger than the simulated one. Such a difference may be explained by the assumption that in this region the fraction of protons increases as much as 3 times, while the slope of the spectrum decreases (γ = 2.6 ÷ 2.7).

Characteristics of cosmic-ray hadronic interactions in the 1015 − 1017 eV range are studied by observing a total of 429 cosmic-ray families of visible energy greater than 100 TeV found in emulsion chamber experiments at high mountain altitudes, Chacaltaya (5200 m above sea level) and the Pamirs (4300 m above sea level). Extensive comparisons were made with simulated families based on models so far proposed, concentrating on the relation between the observed family flux and the behaviour of high-energy showers in the families, hadronic and electromagnetic components. It is concluded that there must be global change in characteristics of hadronic interactions at around 1016 eV deviating from thise known in the accelerator energy range, specially in the forwardmost angular region of the collision. A detailed study of a new shower phenomenon of small-pT particle emissions, pT being of the order of 10 MeV/c, is carried out and its relation to the origin of huge “halo” phenomena associated with extremely high energy families is discussed as one of the possibilities. General characteristics of such super-families are surveyed.

Parameters R ¯ > , ER ¯ > of gamma-hadron families with a visible energy Σ E γ ≥ 100 TeV are analysed with the aim to prove their sensitivity to the mass composition of primary cosmic rays (PCR). The experimental values of these parameters are in agreement with the assumption that PCR become enriched with CNO nuclei at an energy ≥ 10 16 PeV.

Spectrum of “halo” areas in gamma-hadron families with ∑ Eγ ≥ 500 TeV is analyzed. The comparison of experimental data and simulations by quark-gluon string model suggests an increasing contribution of nuclei heavier than protons and α-particles to the primary cosmic radiation (PCR) at energy E0 > 1016 eV. Such a model is consistent both with the accelerator data and those from X-ray emulsion chamber experiments under assumption that PCR mass composition is normal for E0

An exotic cosmic-ray family event is observed in the large emulsion chamber exposed by the joint at the Pamirs (4360 m above sea level). The family is composed of 120 γ -ray-induced showers and 37 hadron-induced showers with individual visible energy exceeding 1 TeV. The decisive feature of the event is the hadron dominance: ΣE γ , ΣE ( γ ) h , 〈 E γ , 〈 E ( γ ) h 〉, 〈 E γ · R γ 〉 and 〈 E ( γ ) · R h 〉 being 298 TeV, 476 TeV, 2.5 TeV, 12.9 TeV, 28.6 GeV m and 173 GeV m, respectively. Most probably the event is due to a Centauro interaction, which occured in the atmosphere at ∼700 m above the chamber. The event will constitute the second beautiful candidate for a Centauro observed at the Pamirs.

Here we present a summary of joint discussions on the results of three mountain experiments with large-scale emulsion chambers, at Pamir, Mt. Fuji and Chacaltaya. Observations cover gamma quanta, hadrons and their clusters (called “families”). The following topics are covered, concerning the characteristics of nuclear interactions the energy region 1014–1016 eV: (i) rapid dissipation seen in atmospheric diffusion of high-energy cosmic-rays; (ii) multiplicity and Pt increase in produced pi-mesons in the fragmentation region; (iii) existence of large-Pt jets, (iv) extremely hadron-rich family of the Centauro type; (v) exotic phenomena in the extremely high energy region beyond 1016 eV.