PAMELA measurements of cosmic-ray proton and helium spectra     

Adriani O  Barbarino GC  Bazilevskaya GA  Bellotti R  Boezio M  Bogomolov EA  Bonechi L  Bongi M  Bonvicini V  Borisov S  Bottai S  Bruno A  Cafagna F  Campana D  Carbone R  Carlson P  Casolino M  Castellini G  Consiglio L  De Pascale MP  De Santis C  De Simone N  Di Felice V  Galper AM  Gillard W  Grishantseva L  Jerse G  Karelin AV  Koldashov SV  Krutkov SY  Kvashnin AN  Leonov A  Malakhov V  Malvezzi V  Marcelli L  Mayorov AG  Menn W  Mikhailov VV  Mocchiutti E  Monaco A  Mori N  Nikonov N  Osteria G  Palma F  Papini P  Pearce M 《Science (New York, N.Y.)》2011,332(6025):69-72

Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 1.2 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics). We find that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data.  相似文献   

Exploitation of SSR,SRAP and CAPS-SNP markers for genetic diversity of Citrus germplasm collection     

Mohamed Hamdy Amar  Manosh Kumar Biswas  Zongwen Zhang  Wen-Wu Guo 《Scientia Horticulturae》2011

The present study was to assess informativeness and efficiency of three different molecular markers for genetic diversity among 24 Citrus and its relative species. Sixty one SSR, 33 SRAP and 24 CAPS-SNP markers were used to evaluate the level of polymorphism and discriminating capacity. A total of 596, 656 and 135 polymorphic amplicons were observed in SSR, SRAP and CAPS-SNP markers with average polymorphism information content (PIC) of 0.97, 0.98 and 0.89, respectively. High levels of polymorphism were recorded for SSR and SRAP compared with CAPS-SNP markers. The highest correlations (r = 0.930) were obtained between SSR and SRAP markers, whereas SSR and CAPS-SNP were poorly correlated (r = 0.833). Cluster analysis was performed to construct dendrograms using UPGMA. And the dendrogram from SSR data was most congruent with the general dendrogram. These findings provide basis for future efficient use of these molecular markers in the genetic analysis of Citrus and its relatives.  相似文献   

Heavy metal pollutant tolerance of Azolla Pinnata     

Amar Sarkar  Sasadhar Jana 《Water, air, and soil pollution》1986,27(1-2):15-18

The effects of Hg, As, Pb, Cu, Cd, and Cr (1, 2, and 5 mg L^?1 each) on Azolla pinnata R. Br. were analyzed. The treatments (2 and 5 mg L^?1) of the heavy metal pollutants decreased Hill activity, chlorophyll, protein and dry wt, and increased tissue permeability over control values. The effects were most pronounced with the treatment of 5 mg L^?1. The harmful effects of the metals were, in general, found by the treatments in the order: Cd 〉 Hg 〉 Cu 〉 As 〉 Pb 〉 Cr. There was no significant change in these parameters at 1 mg L^?1 of the metals over control. Thus Azolla pinnata shows tolerance to the heavy metals tested up to 1 mg L^?1 each.  相似文献   

Cryopreservation of silver barb Puntius gonionotus (Bleeker) spermatozoa: effect of extender composition,cryoprotective agents and freezing rate on their postthawing fertilization ability     

Padmanav Routray  Surjya Narayan Dash  Chidananda Dash  Priyabrat Swain  Sampad Kumar Sarkar  Niranjan Sarangi 《Aquaculture Research》2008,39(15):1597-1605

The effects of extender composition, cryoprotectant concentration and freezing and thawing on the fertilization efficiency of cryopreserved spermatozoa of Puntius gonionotus were evaluated. Computer‐aided motility analysis of semen was conducted to check the suitability of spermatozoa for cryopreservation after mixing with different extenders and cryoprotective agents (CPAs). Extender‐4 with an osmolality 260 mOsmol kg⁻¹and pH 7.6 was used for the cryopreservation study. Among the CPAs, dimethyl sulphoxide (DMSO) was least toxic and more than 60% fertilization was achieved when used at 1.4 M at 0 °C for 10 and 30 min, whereas the toxicity of all CPAs to spermatozoa was evident when tested at 30 °C. Semen frozen at −16 °C min⁻¹ with 1.4 M DMSO showed 70% fertilization, which was significantly higher (P<0.05) than other freezing rates. Samples thawed at 35 °C water showed a fertilization rate comparable with that of fresh semen. Computer‐assisted semen analysis of fresh and frozen semen after thawing showed variations in different types of motility in spermatozoa and in their class. There was no significant difference in motility before or after cryopreservation; however, significant differences could be observed in the average path velocity (VAP), straight line velocity (VSL) and curve linear velocity (VCL). Semen of silver barb could be cryopreserved with extender‐4 by addition of 1.4 M DMSO to a final cryopreservation medium (MED 2) cooled at a rate of −16 °C min⁻¹, stored in liquid nitrogen (−196 °C) and utilized after thawing at 35±2 °C.  相似文献   

The effects of undernutrition of suckled pigs on subsequent growth and body composition after nutritional rehabilitation     

N K Sarkar  G A Lodge  C J Williams  J I Elliot 《Journal of animal science》1983,57(1):34-42

The effect of nutritional restriction and rehabilitation imposed between 5 and 35 d and 35 and 166 d of age, respectively, on body and tissue growth were investigated in 96 Yorkshire pigs from 12 litters. One-half of the pigs were allowed to suckle continuously until weaning (fully fed, FF); the remainder were removed from the sow for 16 h of each 24 h period (1600 to 0800 h), during which time they received only water (restricted feeding, RF). All pigs were fed ad libitum from 35 d of age. Although significantly lower body and tissue (liver, kidney and gastrocnemius muscle) weights were observed in the RF pigs at 35 and 70 d of age, by 166 d, because of compensatory growth between 35 and 166 d, the difference in body and muscle weights between the two groups of pigs (RF and FF) was reduced to 5%, but the difference in kidney and liver weight remained as high as 15 and 9%, respectively. Total DNA, RNA and protein in the tissues examined were also lower in the RF pigs at 35 and 70 d of age, but increased after ad libitum feeding to more than 90% of the corresponding value in the FF pigs by the time they reached 166 d of age. The results of these measurements and the comparison of the protein: DNA ratios of the tissues indicated that growth retardation in the RF pigs was associated with reduced cell proliferation in liver and kidney and nuclear proliferation in muscle rather than any decrease in cell (or fiber) volume. Percentage of fat was lower while percentage of protein was higher (on a dry matter basis) in the RF pigs than in the FF pigs at 35 d of age. No significant difference in fat and protein content in the carcasses between the RF and FF pigs at 70 or 166 d of age or 90 kg body weight was noted. The carcass of intact males had more protein and less fat than that of females.  相似文献   

ARTERIOGRAPHIC ANATOMY OF THE ABDOMINAL AORTA IN THE GOAT, DOG, PIG, AND RABBIT     

Ambika P.  Singh  MVSc  PhD  Gaj Raj  Singh  MVSc  Dwarika N.  Sharma  MVSc  PhD  Janki M.  Nigam  MVSc  PhD  Amar K.  Bhargava  MS  PhD 《Veterinary radiology & ultrasound》1982,23(6):279-281

Arteriographic anatomy of the major branches of the abdominal aorta of rabbits, dogs, pigs, and goats was investigated. The origin and location of the celiac, cranial mesenteric, right renal, left renal, caudal mesenteric, and external iliac arteries were demonstrated, and their placement was described in relation to the iliac bifurcation and lumbar vertebral bodies.  相似文献   

Comparative nucleotide sequence analysis of the phosphoprotein gene of peste des petits ruminants vaccine virus of Indian origin   总被引：2，自引：0，他引：2  

Muthuchelvan D  Sanyal A  Sarkar J  Sreenivasa BP  Bandyopadhyay SK 《Research in veterinary science》2006,81(1):158-164

The nucleotide sequences of the phosphoprotein (P) gene of peste des petits ruminants (PPRV) vaccine virus (PPRV Sungri/96) belongs to Asian lineage have been determined and the deduced amino acid sequences were compared with another vaccine strain PPRV/Nigeria75/1 and with those of the other morbilliviruses. The 1652 nucleotides of the P gene encode a phosphoprotein of 509 amino acid residues (from nucleotide numbers 60 to 1587), which is 91% identical to that of PPRV/Nigeria75/1. The C protein consists of 177 amino acid residues and is 91% identical with that of PPRV/Nigeria75/1. The conserved mRNA editing site (5'TTAAAAGGGCACAG) was present at positions 742-756 in the P gene, which is conserved in all other morbilliviruses. The CTT trinucleotide sequence is present at the N/P and P/M intergenic region, which is totally conserved in morbilliviruses. This will be the third sequence for the P gene of PPRV since that of the vaccine strain and a wild-type Turkish isolate has been published already.  相似文献   

GGE biplot analysis to evaluate genotype, environment and their interactions in sorghum multi-location data   总被引：1，自引：0，他引：1  

Sujay Rakshit  K. N. Ganapathy  S. S. Gomashe  A. Rathore  R. B. Ghorade  M. V. Nagesh Kumar  K. Ganesmurthy  S. K. Jain  M. Y. Kamtar  J. S. Sachan  S. S. Ambekar  B. R. Ranwa  D. G. Kanawade  M. Balusamy  D. Kadam  A. Sarkar  V. A. Tonapi  J. V. Patil 《Euphytica》2012,185(3):465-479

Sorghum [Sorghum bicolor (L.) Moench] is a very important crop in the arid and semi-arid tropics of India and African subcontinent. In the process of release of new cultivars using multi-location data major emphasis is being given on the superiority of the new cultivars over the ruling cultivars, while very less importance is being given on the genotype?×?environment interaction (GEI). In the present study, performance of ten Indian hybrids over 12 locations across the rainy seasons of 2008 and 2009 was investigated using GGE biplot analysis. Location attributed higher proportion of the variation in the data (59.3–89.9%), while genotype contributed only 3.9–16.8% of total variation. Genotype?×?location interaction contributed 5.8–25.7% of total variation. We could identify superior hybrids for grain yield, fodder yield and for harvest index using biplot graphical approach effectively. Majority of the testing locations were highly correlated. ‘Which-won-where’ study partitioned the testing locations into three mega-environments: first with eight locations with SPH 1606/1609 as the winning genotypes; second mega-environment encompassed three locations with SPH 1596 as the winning genotype, and last mega-environment represented by only one location with SPH 1603 as the winning genotype. This clearly indicates that though the testing is being conducted in many locations, similar conclusions can be drawn from one or two representatives of each mega-environment. We did not observe any correlation of these mega-environments to their geographical locations. Existence of extensive crossover GEI clearly suggests that efforts are necessary to identify location-specific genotypes over multi-year and -location data for release of hybrids and varieties rather focusing on overall performance of the entries.  相似文献   

Prevalence,molecular fingerprinting and drug resistance profile of enterovirulent <Emphasis Type="Italic">Escherichia coli</Emphasis> isolates from free-ranging yaks of Tawang district,Arunachal Pradesh,India     

Bandyopadhyay S  Lodh C  Sarkar M  Ghosh MK  Bera AK  Bhattacharyya D  Mondal DK  Baruah KK 《Tropical animal health and production》2012,44(5):1063-1072

Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.  相似文献   

绿叶汁发酵液为添加剂改善玉米青贮品质的研究     

严萍  张永辉  麦热姆妮萨·  艾麦尔 《草业科学》2012,29(1):160-164

本研究以饲料玉米(Zea mays)为原料,采用绿叶汁发酵液1.0%、1.5%、2.0%作青贮添加剂,并与传统青贮工艺添加1%、3% NaCl做比较,在实验室条件下贮藏60 d。测定其青贮品质(包括微生物群落结构、pH值、粗蛋白、干物质、纤维素含量、有机酸含量)及体外消化率,并与传统青贮工艺做比较。结果显示,添加绿叶汁发酵液可以明显改善青贮品质,pH值显著降低,干物质、粗蛋白及有机酸含量均有显著性增加(P<0.05)。经体外消化试验可知,与对照相比,添加绿叶汁发酵液可显著提高青贮饲料消化率。  相似文献