N ucleic a c id m etabolism of th e b r in e shrim p, Artem ia s a l i n a , has been th e s u b je c t o f r e c e n t in v e s t ig a t io n a t th e Oak Ridge N a tio n a l L a b o ra to r ie s (U .S .A .) t o determ ine th e source o f n u c le ic a c id p u rin e s r e l a t i v e t o th e c e l l u l a r n u c le o tid e p oo ls d u rin g developm ent. As a seq u e l t o t h i s work, and...

Fi lms of e th ylen e conde nsed ont o a co ld fin ge r ma int a ine d a t 20 K we re ir radi a ted with photons whose e ne rgy ra nged fro m 8.4 to 21.2 e V. At the highe r ph oton e ne rgies th e re la tive yie lds of produc ts co mpa re we ll with those seen in th e radi o lys is of so lid e th yle ne. Expe rime nt s on C H2C D2 d e m ons tra te th a t in the photo lys is h ydrogen is ma inl...

Depth profiles of total Th (dissolved+particulate) were collected at Station ALOHA (22145N, 158100W) in the North Pacific Subtropical Gyre during 9 cruises from April 1999 to March 2000. Samples were collected and processed by a new 2L technique that enables more detailed depth resolution then previous Th studies. Significant zones of particle export (Th deficiency) and particle remineralizatio...

in this study, the ion association phenomenon in the saturated solution of kcl in the mixed solvent(methanol+water) was studied. the solubility of this compound in the mixed solvent (methanol+water by value percent of methanol = 60%), and in the presence of various molarities of nano3 wasdetermined by the solvent evaporation method at 25.0°c. the results enable us to estimate the valueof thermo...

in te re s t in s e v e ra l fi e ld s , e s p e c ia ll y in g e o p h y s ic s , w h e re s u c h e x p e ri m e n ts a re u s e d to s tu d y h ig h p re s s u re b e h a v io r o f e a rt h m a te ri a ls . Im p a c ts g e n e ra te d in th e s e e x p e ri m e n ts s o m e ti m e s in d u c e p h a s e c h a n g e s . T h is ta lk d e s c ri b e s th e a p p li c a ti o n to im p a c tin d...

The study of the carbonate cements in the Permian-Triassic Dalan-Kangan formations resulted in the identification of five stages of calcite and dolomite cementation, which completely or partially occluded pores. Cement types appear to be early isopachous calcite (i; C1-non-luminescence), equant (ii; C2-dull CL), fairly coarse secondary dolomite rhombs (iii; C3-zoning red CL), coarse sparry calc...

In th is a rtic le we focus on som e restric tions we m ay im pose on Tree H om om orphic F ea tu re S tru c tu re G ram m ar (THFSG) regard ing th e em pty strin g . A fter defin ing the re s tric tio n s , we prove som e closure p ro p erties of th e two new classes of languages these re s tr ic tio n s give us. F u rtherm ore , we estab lish th a t th e m em bersh ip prob lem is PSPA C E com...

Sin ce 198 7, ice co res have bee n clri ll ecl from th e Duncl e a nd Gu li ya ice caps on th e Tibeta n Pl a teau, wes tern C hin a . H ere, th e oxygen iso topi c (80 ) records for th e las t 1000 yea rs from both th ese co res a re compil ed a nd compa red. Using surfa ce tempera ture obse rva ti ons since th e micl-l960s from meteorologica l sta ti ons on th e pl a teau a nd 60 measured on...

Let X be a Hausdorff compact space and C(X) be the algebra of all continuous complex-valued functions on X, endowed with the supremum norm. We say that C(X) is (approximately) n-th root closed if any function from C(X) is (approximately) equal to the n-th power of another function. We characterize the approximate n-th root closedness of C(X) in terms of ndivisibility of first Čech cohomology gr...