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First Pair (first + pair)
Selected AbstractsSpatial and temporal 850 hPa air temperature and sea-surface temperature covariances in the Mediterranean region and their connection to atmospheric circulationINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2002C. J. Lolis Abstract The spatial and temporal covariability between the lower troposphere and sea surface temperatures (SSTs) are studied in the Mediterranean basin for the period 1958,98. Monthly air temperature anomalies for the 850 hPa pressure level (T-850hPa) at 2.5° × 2.5° grid points and SST anomalies in 5° × 5° grid boxes are utilized. As a first step, factor analysis is applied on both sets of data in order to reduce their dimensionality. Then, canonical correlation analysis is applied and this leads to one statistically significant pair of canonical variates for winter and to two pairs for summer. In winter, a teleconnection (see-saw) between western Europe and the eastern Mediterranean at the 850 hPa level is revealed, and a corresponding weaker one between the areas of central-west and eastern Mediterranean for SST. The correlation between T-850hPa and SST appears higher over the eastern Mediterranean. In summer, the first pair of canonical variates reveals a covariability between T-850hPa and SST in the western Mediterranean, and the second one shows a covariability in the eastern Mediterranean, without the existence of any strong spatial teleconnection. The analysis is repeated, using time lags of 1 month, or longer, in order to detect any possible non-synchronous relation. Statistically significant results are found only when T-850hPa leads SST with a time lag of 1 month. In particular, the results are statistically significant for winter only, and the findings are similar to those of the first analysis. Therefore, the existence of a 1 month time scale SST persistence is detected for winter months. Copyright © 2002 Royal Meteorological Society. [source] Crystal structure of calcium-free human sorcin: A member of the penta-EF-hand protein familyPROTEIN SCIENCE, Issue 12 2001Xiaoling Xie Abstract Sorcin is a 22 kD calcium-binding protein that is found in a wide variety of cell types, such as heart, muscle, brain and adrenal medulla. It belongs to the penta-EF-hand (PEF) protein family, which contains five EF-hand motifs that associate with membranes in a calcium-dependent manner. Prototypic members of this family are the calcium-binding domains of calpain, such as calpain dVI. Full-length human sorcin has been crystallized in the absence of calcium and the structure determined at 2.2 Å resolution. Apart from an extended N-terminal portion, the sorcin molecule has a globular shape. The C-terminal domain is predominantly ,-helical, containing eight ,-helices and connecting loops incorporating five EF hands. Sorcin forms dimers through the association of the unpaired EF5, confirming this as the mode of association in the dimerization of PEF proteins. Comparison with calpain dVI reveals that the general folds of the individual EF-hand motifs are conserved, especially that of EF1, the novel EF-hand motif characteristic of the family. Detailed structural comparisons of sorcin with other members of PEF indicate that the EF-hand pair EF1,EF2 is likely to correspond to the two physiologically relevant calcium-binding sites and that the calcium-induced conformational change may be modest and localized within this pair of EF-hands. Overall, the results derived from the structural observations support the view that, in sorcin, calcium signaling takes place through the first pair of EF-hands. [source] Enantiotropic phase transition and twinning in 2,2,3,3,4,4-hexafluoropentane-1,5-diolACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Jeong-Myeong Ha Four crystal structure determinations of 2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD), C5H6F6O2, were conducted on a single specimen by varying the temperature. Two polymorphs of HFPD were found to be enantiotropically related as phases (I) and (II), both in the space group P1. These structures contain closely related R44(20) sheets. A structure determination was completed on form (Ia) at 283,K. Form (Ia) was then supercooled below the phase transition temperature at 279 to 173,K to give form (Ib) for a second structure determination. Metastable form (Ib) was transformed by momentary warming and recooling to give form (II) for a third structure determination at 173,K. Form (II) transformed to form (Ic) upon warming to 283,K. Enantiotropic phase transitions between phases (I) and (II) were confirmed with X-ray powder diffraction and differential scanning calorimetry. Form (Ia) was found as a twin by nonmerohedry by a reflection in (011). This twinning persists in all phases described. Additional twinning was found after the phase (I) to phase (II) transformation. These two additional twin components are related to the first pair by a 180° rotation about the (012) plane. This latter pair of twins persisted as the specimen was warmed back to form (Ic) at 283,K. [source] Linkage isomeric oxamate chelates: rac -bis(ethane-1,2-diamine)oxamatocobalt(III) bis(trifluoromethanesulfonate) dihydrate and ,(+)578 -bis(ethane-1,2-diamine)[oxamato(2,)]cobalt(III) trifluoromethanesulfonateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Anders Hammershøi The structures of rac -bis(ethane-1,2-diamine)(oxamato-,2O1,O2)cobalt(III) bis(trifluoromethanesulfonate) dihydrate, [Co(C2H2NO3)(C2H8N2)2](CF3SO3)2·2H2O, (I), and ,(+)578 -bis(ethane-1,2-diamine)[oxamato(2,)-,2N,O1]cobalt(III) trifluoromethanesulfonate, [Co(C2HNO3)(C2H8N2)2]CF3SO3, (II), are compared. Together, the two complexes constitute the first pair of linkage isomers of bidentate oxamate available for structural comparison. [source] Reproduction, early development and larviculture of the barber goby, Elacatinus figaro (Sazima, Moura & Rosa 1997)AQUACULTURE RESEARCH, Issue 1 2009Maria Eugenia Meirelles Abstract The barber goby, Elacatinus figaro, is a cleaner species of ecological importance and of keen interest to the aquarium trade. Endemic to Brazil, it is a threatened species and so aquaculture is a potential solution for reducing pressure on the natural stocks. This study describes the reproductive behaviour, the embryonic and larval development and the general breeding and rearing conditions. Ten wild fish initiated the formation of breeding pairs 20 days after acclimation to captivity. Spawning started 12 days after the first pair was formed, with one female from each pair spawning from 140 to 700 eggs (n=15 spawnings). The average period of incubation of the eggs was 6.8 days at 25 °C. The best hatching rate was 99.5% (n=10 spawnings). Larval rearing used Nannochloropsis oculata with rotifers (Brachionus rotundiformis) as the first food (day 0,25); nauplii and meta-nauplii of Artemia were fed from day 18 until larval metamorphosis with subsequent weaning using commercial marine fish diets. The transformation to juveniles started at around the 30th day post hatch. The best larval survival rate until complete metamorphosis was 30.6% (n=4 larvicultures). After this period, the mortality was insignificant. This study demonstrated that the cultivation of barber goby is feasible. [source] Environmental sex determination, external sex differentiation and structure of the androgenic gland in the Pacific white shrimp Litopenaeus vannamei (Boone)AQUACULTURE RESEARCH, Issue 15 2006Rafael Campos-Ramos Abstract Environmental effects on sex determination in Litopenaeus vannamei were studied by rearing day 1 postlarvae at three temperatures, under three photoperiods, at high density and by starving. None of the environmental conditions affected sex determination or differential development of gender in this species. From day 50, the development of the endopodite of the first pair of pleopods revealed the first external differentiation, showing a triangular structure with three setae in females, whereas a tubular structure remained in males. Juvenile shrimp sex differentiation took place from days 50,90, independent of size, only if postlarvae reached a development threshold of 150 mg of body weight and 20 mm of body length previously. Histology and scanning electron microscopy of the vas deferens revealed that the androgenic gland (AG) is a single 2-mm cord attached in the subterminal ejaculatory region, just before the distal vas deferens narrows. The AG is composed of large oval cells containing vacuolated cytoplasm, and each cell has a prominent rounded nucleus, similar to all descriptions of the AG in Malacostracans, so we assume that it should have the same function in sex differentiation. [source] | |||||||||||||