Using bioacoustic tools to clarify species delimitation within the Blakiston's Fish Owl(Bubo blakistoni)complex     

Nyanasengeran Movin  Tatjana Gamova  Sergei G.Surmach  Jonathan C.Slaght  A.A.Kisleiko  James A.Eaton  Frank E.Rheindt 《中国鸟类》2022,(1):17-24

Although Blakiston's Fish Owl(Bubo blakistoni)is widely treated as a single species,marked differences in the structure of pair duets between continental and in...  相似文献   

Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters     

Coale KH  Johnson KS  Chavez FP  Buesseler KO  Barber RT  Brzezinski MA  Cochlan WP  Millero FJ  Falkowski PG  Bauer JE  Wanninkhof RH  Kudela RM  Altabet MA  Hales BE  Takahashi T  Landry MR  Bidigare RR  Wang X  Chase Z  Strutton PG  Friederich GE  Gorbunov MY  Lance VP  Hilting AK  Hiscock MR  Demarest M  Hiscock WT  Sullivan KF  Tanner SJ  Gordon RM  Hunter CN  Elrod VA  Fitzwater SE  Jones JL  Tozzi S  Koblizek M  Roberts AE  Herndon J  Brewster J  Ladizinsky N  Smith G  Cooper D  Timothy D  Brown SL  Selph KE  Sheridan CC  Twining BS 《Science (New York, N.Y.)》2004,304(5669):408-414

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.  相似文献   

Density of Mars' south polar layered deposits     

Zuber MT  Phillips RJ  Andrews-Hanna JC  Asmar SW  Konopliv AS  Lemoine FG  Plaut JJ  Smith DE  Smrekar SE 《Science (New York, N.Y.)》2007,317(5845):1718-1719

Both poles of Mars are hidden beneath caps of layered ice. We calculated the density of the south polar layered deposits by combining the gravity field obtained from initial results of radio tracking of the Mars Reconnaissance Orbiter with existing surface topography from the Mars Orbiter Laser Altimeter on the Mars Global Surveyor spacecraft and basal topography from the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express spacecraft. The results indicate a best-fit density of 1220 kilograms per cubic meter, which is consistent with water ice that has approximately 15% admixed dust. The results demonstrate that the deposits are probably composed of relatively clean water ice and also refine the martian surface-water inventory.  相似文献   

Fat mobilization in adipose tissue is promoted by adipose triglyceride lipase   总被引：3，自引：0，他引：3  

Zimmermann R  Strauss JG  Haemmerle G  Schoiswohl G  Birner-Gruenberger R  Riederer M  Lass A  Neuberger G  Eisenhaber F  Hermetter A  Zechner R 《Science (New York, N.Y.)》2004,306(5700):1383-1386

Mobilization of fatty acids from triglyceride stores in adipose tissue requires lipolytic enzymes. Dysfunctional lipolysis affects energy homeostasis and may contribute to the pathogenesis of obesity and insulin resistance. Until now, hormone-sensitive lipase (HSL) was the only enzyme known to hydrolyze triglycerides in mammalian adipose tissue. Here, we report that a second enzyme, adipose triglyceride lipase (ATGL), catalyzes the initial step in triglyceride hydrolysis. It is interesting that ATGL contains a "patatin domain" common to plant acyl-hydrolases. ATGL is highly expressed in adipose tissue of mice and humans. It exhibits high substrate specificity for triacylglycerol and is associated with lipid droplets. Inhibition of ATGL markedly decreases total adipose acyl-hydrolase activity. Thus, ATGL and HSL coordinately catabolize stored triglycerides in adipose tissue of mammals.  相似文献   

Venus: an upper limit on intrinsic magnetic dipole moment based on absence of a radiation belt     

Van Allen JA  Krimgis SM  Frank LA  Armstrong TP 《Science (New York, N.Y.)》1967,158(3809):1673-1675

On the basis of the absence of energetic electrons (E(e) 45 kiloelectron volts) and protons (E(p) 320 kiloelectron volts) associated with Venus to within a radial distance of 10,150 kilometers from the center of the planet and using a physical similitude argument and the observational and theoretical knowledge of the magnetosphere of Earth, we conclude that the intrinsic magnetic dipole moment of Venus is almost certainly less than 0.01 and probably less than 0.001 of that of Earth. Corresponding upper limits on the magnetic field at the equatorial surface of Venus are about 350 and 35 x 10(-5) gauss, respectively.  相似文献   

Separation of metallic from semiconducting single-walled carbon nanotubes     

Krupke R  Hennrich F  Löhneysen Hv  Kappes MM 《Science (New York, N.Y.)》2003,301(5631):344-347

We have developed a method to separate metallic from semiconducting single-walled carbon nanotubes from suspension using alternating current dielectrophoresis. Our method takes advantage of the difference of the relative dielectric constants of the two species with respect to the solvent, resulting in an opposite movement of metallic and semiconducting tubes along the electric field gradient. Metallic tubes are attracted toward a microelectrode array, leaving semiconducting tubes in the solvent. Proof of the effectiveness of separation is given by a comparative Raman spectroscopy study on the dielectrophoretically deposited tubes and on a reference sample.  相似文献   

The effect of systemic pesticides on total glycoalkaloid content of potato tubers at harvest     

J. M. Wilson  J. S. Frank 《American Journal of Potato Research》1975,52(6):179-184

Two studies were conducted to determine the effect of systemic pesticides on the potato tuber total glycoalkaloid (TGA) content at harvest. In a field study, a pretuberization application of three systemic insecticides (disulfoton, aldicarb, carbofuran) and three systemic fungicides (thiabendazole, benomyl, thiophanate methyl) on three potato cultivars (Cobbler, Katahdin and B5141-6) showed carbofuran to be the only treatment significantly different (P= .05) from the control. The tuber TGA content of the carbofuran treatment was lower than that of the control. In a greenhouse study, carbofuran applied during tuberization to three potato varieties (Norland, Kennebec, Abnaki) produced a highly significant increase (P= .01) in the tuber TGA content. A significant varietal difference (P=.01) in response to the carbofuran treatment was also evidenced.  相似文献   

Russette: A Russet-skin potato variety,combining high quality,high yields,and adaptation to the Northeastern states and Florida     

R. E. Webb  D. R. Wilson  J. A. Frank  R. W. Goth  J. R. Shumaker  M. R. Henninger 《American Journal of Potato Research》1984,61(2):77-81

Russette is a new, late maturing, russet potato variety adapted primarily for the northeastern United States and northern Florida. Tubers are oval to oblong, smooth with a medium-russet skin, and shallow eyes. Its specific gravity is similar to those of BelRus and Russet Burbank in areas of adaptation. Glycoalkaloid content is about 11 mg/100 g fresh weight. Baking quality is excellent, flesh is white, and best color of french fries is obtained from tubers stored at or above 13°C (55°F). Its long rest period makes it amenable to storage at a relatively high temperature before a chemical sprout inhibitor is needed. Russette is immune to virus A and leaf roll-induced tuber net necrosis; highly resistant to Verticillium wilt, tuber pinkeye, and tuber heat necrosis; and has good tolerance to scab, early blight, and Rhizoctonia infection of sprouts, stolon, and roots. Losses to rots and shrinkage in storage have been minimal. Russette is not resistant to viruses X, S, Y, and leaf roll and bacterial ring rot. Russette emerges to a stand about 10 days later than most varieties, however, subsequent vine growth is rapid until tuberization begins. Large-sized tubers may develop hollow heart under a late-season regime of high nitrogen and high moisture. A 22–30 cm (9″- to -12″) seed-piece spacing and 220 kg/ha (180 pounds/a) of nitrogen are recommended for production on mineral soils.  相似文献   

The use ofStreptococcus zymogenes for estimating tryptophan and methionine bioavailability in 17 foods     

Patricia Wells  Frank McDonough  C. E. Bodwell  Anthony Hitchens 《Plant foods for human nutrition (Dordrecht, Netherlands)》1989,39(1):121-127

As part of a cooperative study assessing amino acid bioavailability and/or protein quality, the provisional method of Boyneet al. (Brit J Nutr 21: 181–206) was used to assay 17 protein sources for methionine and tryptophan availability withS. zymogenes. Pronase was used as the predigesting enzyme. Product composition was found to affect reproducibility. The microbial assay results correlated positively with results from rat growth studies on the same foods (p=0.05), and were generally accurate in identifying products of lower protein quality. Defatting four high-fat products increased microbial values in the methionine assay, but only the chicken franks and the sausage values in the tryptophan assay. Heating non-fat milk increased methionine values slightly. Low values for rolled oats were further reduced by finer grinding.  相似文献   

The potential for incorporating herbicides into a mulch farming system in Costa Rica     

Frank S. Conklin  Thomas V. McCarty  Stanley F. Miller 《Crop Protection》1982,1(4):441-451

Experiments on the use of herbicides in the mulch farming system of the North Atlantic Zone of Costa Rica have given promising results. In order to ascertain whether extension of investigations to farm-field trials is warranted, 20 farms were surveyed, providing data which facilitated comparison between the net benefits of the traditional weed-control methods and those of the new system incorporating herbicides. The results indicate that, without taking crop-yield increase into account, approximately 30% of the farms sampled would have increased their cash income by adopting the new weed-control system. This figure increases to 50% when the yield increase recently reported is considered. The new system is particularly promising in areas heavily infested with weeds such as Rottboellia exaltata and Panicum maximum. In our view, these results justify advancing the research from experimental plots to farm-field trials.  相似文献