Glacial survival of boreal trees in northern Scandinavia     

Parducci L  Jørgensen T  Tollefsrud MM  Elverland E  Alm T  Fontana SL  Bennett KD  Haile J  Matetovici I  Suyama Y  Edwards ME  Andersen K  Rasmussen M  Boessenkool S  Coissac E  Brochmann C  Taberlet P  Houmark-Nielsen M  Larsen NK  Orlando L  Gilbert MT  Kjær KH  Alsos IG  Willerslev E 《Science (New York, N.Y.)》2012,335(6072):1083-1086

It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west-an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Tr?ndelag in central Norway dating back ~10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free And?ya refugium in northwestern Norway as early as ~22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.  相似文献   

Interactions between earthworms (Aporrectodea caliginosa), plants and crop residues for restoring properties of a degraded arable soil The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

Patricia M. Fraser  Michael H. Beare  Ruth C. Butler  Tina Harrison-Kirk  Jacqueline E. Piercy 《Pedobiologia》2003,47(5-6):870-876

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Chemical analysis of Radix Astragali (Huangqi) in China: a comparison with its adulterants and seasonal variations   总被引：8，自引：0，他引：8  

Ma XQ  Shi Q  Duan JA  Dong TT  Tsim KW 《Journal of agricultural and food chemistry》2002,50(17):4861-4866

Radix Astragali (root of Astragalus; Huangqi) is a popular traditional Chinese medicine, and Astragalus membranaceus and A. membranaceus var. mongolicus are two commonly used species; however, there are many Astragalus species that could act as adulterants of Radix Astragali. To find the chemical composition of Radix Astragali, the main constituents including flavonoids, saponins, polysaccharides, amino acids, and trace elements were determined in two Radices Astragali, A. membranaceus and A. membranaceus var. mongolicus, and its eight adulterants, Astragalus propinquus, Astragalus lepsensis, Astragalus aksuensis, Astragalus hoantchy, Astragalus hoantchy subsp. dshimensis, Astragalus lehmannianus, Astragalus sieversianus, and Astragalus austrosibiricus. The results showed that the amounts of main constituents such as isoflavonoids and astragalosides varied in different species. In distinction, A. membranaceus and A. membranaceus var. mongolicus contained a higher amount of astragaloside I and IV. In addition, the main constituents of A. membranaceus var.mongholicus changed according to seasonal variation and age of the plant. The chemical composition of different species of Astragalus would provide useful information for the quality control of Radix Astragali.  相似文献   

The effects of clearcutting on snowshoe hare (Lepus americanus) relative abundance in central Labrador     

Tina L. Newbury  Neal P.P. Simon 《Forest Ecology and Management》2005,210(1-3):131-142

To assess the effects of clearcutting on snowshoe hare (Lepus americanus) relative abundance, we surveyed pellets in 1 m² circular plots and, vegetation and browse surveys in 4.5 m² circular plots among four different aged clearcut (30, 20, 10, 5 years post-harvest) and mature forests (>150 years old) in central Labrador, Canada. Data were modelled at three grain sizes: transect (4400 m²), plot (314 m²) and subplot scales (4.5 m²). Betula papyrifera, distance from mature forest edge, tree and herb cover as well as remotely sensed forest inventory data were used as predictors for hare pellets. We found pellet abundance was 5 and 37 times greater (new and old pellets, respectively) in clearcut stands 30 years old than the next highest in 20 year old cuts. There were few hare pellets in the remaining stand ages. B. papyrifera was the most proportionately used browse species and most important of our fine-detailed vegetation in predicting hare pellets. The coarse-detailed, forest inventory and topographic data better predicted hare pellets than the fine-detailed vegetation data.  相似文献   

Multivariate principal component analysis to evaluate growth performances in Malabari goats of India     

Valsalan  Jamuna  Sadan  Tina  Venketachalapathy  Thirupathy 《Tropical animal health and production》2020,52(5):2451-2460

Tropical Animal Health and Production - Evaluation of growth performances in Malabari goats was done with body weight and major morphometric traits, viz. body height, body length and chest girth at...  相似文献   

Radiographic vertebral left atrial size: A reference interval study in healthy adult dogs     

Tommaso Vezzosi  Caterina Puccinelli  Rosalba Tognetti  Tina Pelligra  Simonetta Citi 《Veterinary radiology & ultrasound》2020,61(5):507-511

Thoracic radiography is a useful technique for the evaluation of cardiac dimensions, especially when echocardiography is not possible. The vertebral left atrial size (VLAS) has recently been proposed as a new radiographic method for quantifying left atrial dimensions in dogs. The aims of this retrospective, reference interval, observational study were to describe values for VLAS in a group of healthy adult dogs and to compare intraobserver and interobserver agreement for VLAS versus vertebral heart score (VHS) methods. Thoracic radiographs of 80 healthy adult dogs were evaluated. Normal left atrial size was determined based on an echocardiographic left atrial‐to‐aorta ratio < 1.6. The VLAS and vertebral heart score values were measured from right lateral radiographs. The correlations between VLAS, the vertebral heart score, and the left atrial‐to‐aorta ratio were evaluated. The effects of body weight, sex, and age were also tested using regression analyses. The median value of VLAS were 1.9, with a reference interval of 1.4‐2.2. A positive correlation was found between VLAS and vertebral heart score values (r = 0.53; P < .0001). No effect of body weight, sex, and age on VLAS was detected. Excellent intraobserver and interobserver agreements were found for both VLAS and vertebral heart score methods (intraclass correlation coefficients ≥ 0.91). Findings from this sample of healthy dogs indicated that VLAS is a repeatable radiographic method for quantifying left atrial size. Further studies are warranted to evaluate this measure in clinically affected dogs.  相似文献   

Systemic lime sulfur toxicosis secondary to dermal exposure in two cats     

Colette E. Nix  Justine A. Lee  Tina Wismer 《Journal of Veterinary Emergency and Critical Care》2020,30(3):302-307

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Monitoring of spirodiclofen susceptibility in field populations of European red mites, Panonychus ulmi (Koch) (Acari: Tetranychidae), and the cross-resistance pattern of a laboratory-selected strain     

Kramer T  Nauen R 《Pest management science》2011,67(10):1285-1293

BACKGROUND: Phytophagous mites such as the European red mite, Panonychus ulmi (Koch), are serious pests in European fruit tree orchards, and a number of acaricides are frequently used to control them. Spirodiclofen (Envidor^®) has been a commonly used acaricide for several years. In the present study, European field populations collected in 2009 and 2010 were checked for their susceptibility to spirodiclofen by using discriminating dose and full dose response bioassays. RESULTS: In 2009 and 2010, a total of 63 field populations (including winter eggs) of European red mites were collected in different European countries, and in several populations from south‐western Germany a shifting in susceptibility against spirodiclofen was observed. Full dose response bioassays on different developmental stages of field‐collected strains suggested an age‐dependent expression of resistance because eggs remain fully susceptible to spirodiclofen. Artificial selection with spirodiclofen of one of the field strains resulted in resistance ratios of > 7000. Synergism studies suggest a possible role of cytochrome‐P450‐dependent monooxygenases in spirodiclofen detoxification. Most of the other acaricides from different chemical classes displayed no or low cross‐resistance in a spirodiclofen‐selected strain. CONCLUSION: In order to preserve spirodiclofen as an important tool in spider mite resistance management, the efficacy situation should be continuously monitored, and it is suggested that spirodiclofen be alternated with acaricides coming from different mode‐of‐action classes. An observed age‐specific expression of resistance revealed full susceptibility of eggs, so targeting spirodiclofen particularly against eggs is likely to reduce the selection pressures imposed on other life stages. Copyright © 2011 Society of Chemical Industry  相似文献   

Pilot evaluation of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Food-O-Meter, a computer-tailored nutrition advice for adolescents: a study in six European cities     

Maes L  Cook TL  Ottovaere C  Matthijs C  Moreno LA  Kersting M  Papadaki A  Manios Y  Dietrich S  Hallström L  Haerens L  De Bourdeaudhuij I  Vereecken C;HELENA Study Group 《Public health nutrition》2011,14(7):1292-1302

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THE SOYBEAN CROP IN THE UNITED STATES     

VON Struve AW 《Science (New York, N.Y.)》1941,93(2404):86-87

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