The influence of highly intensive single impulses on the cochlea of guinea pig was studied in an acute experiment. Very short impulses of less than or equal to 0.1 ms duration were produced by a sparknoise generator. The cochlear microphonics (CM) to a test stimulus (sinus tone, 3150 Hz) were recorded from the round window and measured prior to, during, and following impulse treatment. During the impulse treatment, the greatest amplitude reduction of CM occurred after the first impulse, while the further impulses caused a decreasing reduction. At first the number of impulses was varied: 1, 3, and 5 impulses were applied at intervals of 15 s each, at an impulse sound level of 164 dB sound pressure level re. 0.002 mubar (SPL). After these impulse treatments, in all cases a continual decrease of CM amplitudes up to a constant end value without recovery was found within a 2-hrs period of observation. The height of the end value depends on the number of impulses applied. Subsequently, at an exposure to 5 impluses the impulse sound level was stepwise reduced (164, 153, 144, 139 and 133 dB SPL). Again, a characteristic decrease of CM amplitudes was observed during the 2-hrs period of observation. The height of the end value is now dependent on the impluse sound level. Impulses of 164, 153 and 144 dB SPL cause a strong decrease of CM while the effect of impulses of 139 and 133 dB SPL is distinctly lower.

Abstract A graph theoretical method is developed which enables to calculate the contribution of a particular ring to the total π-electron energy of a conjugated molecule.

Borove i hrastove šume su višestruko značajno prirodno bogatstvo. Iz njih se dobijaju vrlo cijenjeni drvni sortimenti, a ujedno predstavljaju i elemenat zaštite i unapredjenja čovjekove radne i životne okoline. U BIH visoke šume bora rasprostiru se na oko 86 hiljada ha, a visoke šume hrasta kitnjaka na oko 102 hiljade ha. Medjutim, usljed dosadašnjeg neracionalnog gazdovanja, kvalitet drvnih zaliha i prirast ne zadovoljavaju. Zato su potrebna naučna istraživanja koja će ukazati na to kakve zahvate treba preduzeti u ovim šumama da bi se najbolje iskoristile proizvodne mogućnosti raspoloživog zemljišta radi kvantitativnog i kvalitativnog povećanja drvne mase ove dvije vrste drveća, istraživanja su započeta u onim šumama bora i hrasta (tzv, ekonomskim) koje bi mogle, izborom odgovarajućih tehnoloških poduhvata, dati što brže i povoljnije ekonomske efekte.

Značajna sirovlnska baza šumarske privrede u SR Bosni i Hercegovini, stalan i intenzivan porast potrošnje šumskih odnosno drvnih proizvoda, a uz nedovoljno proučeni način gazdovanja u šumarstvu Bosne i Hercegovine, zahtijevaju istraživanje mjera koje će obezbijediti potpunije i optimalnije korišćenje, obnavljanje i unapredjivanje proizvodnog potencijala šuma, šumskog zemljišta i postojećeg drvnog fonda u šumama Bosne i Hercegovine. Do danas nije bilo naučno verifikovanog stava o tome kako se ekonomski optimalno može gospodariti šumama Bosne i Hercegovine. U većini šuma nije konsenkventno primjenjivan odredjenl sistem gospodarenja, jer se načinu korišćenja šumom i gazdovanja šumama, uglavnom, praktistički prilazilo, bez teorijski dovoljno proučenog sistema gospodarenja.