Role of roots in winter water relations of Engelmann spruce saplings     

Boyce RL  Lucero SA 《Tree physiology》1999,19(13):893-898

Roots play a role in maintaining foliar water balance in subalpine conifer saplings during winter. We used deuterium-labeled water to demonstrate that roots of Engelmann spruce (Picea engelmannii Parry) take up water during the late-winter-early spring period. Based on a root severing experiment, we conclude that small, snow-covered saplings were largely dependent on root water uptake to meet winter transpiration needs, whereas larger saplings relied more on water stored in stem sapwood. Both water uptake and water stored in roots appeared to be critical for the survival of saplings exposed above the snowpack during the late-winter-early spring period, when sap reserves were insufficient to meet increasing transpirational demands.  相似文献   

Geological history of the Western north pacific     

Fischer AG  Heezen BC  Boyce RE  Bury D  Douglas RG  Garrison RE  Kling SA  Krasheninnikov V  Lisitzin AP  Pimm AC 《Science (New York, N.Y.)》1970,168(3936):1210-1214

A considerable portion of the abyssal floor of the western North Pacific was already receiving pelagic sediment in late Jurassic time. Carbonate sediments were later replaced by abyssal clays as the basin deepened and bottom waters became more aggressive. The resulting facies boundary, which can be recognized on seismic profiles, is broadly transgressive; it ranges in age from mid-Cretaceous in the western Pacific to Oligocene in the central Pacific. Cherts are encountered at and below the major facies boundary and appear to have been formed by postdepositional processes.  相似文献   

Review of recent literature     

WM. Stuart 《American Journal of Potato Research》1928,5(6):182-182

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Errata     

WM Webster  BA Reynolds 《New Zealand veterinary journal》2013,61(3)

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Earth-Based Radio Tracking of the Galileo Probe for Jupiter Wind Estimation     

WM Folkner  RA Preston  JS Border  J Navarro  WE Wilson  M Oestreich 《Science (New York, N.Y.)》1997,275(5300):644-646

Although the Galileo probe was designed to communicate only to the orbiter, the probe radio signal was detected at two Earth-based radio observatories where the signal was a billion times weaker. The measured signal frequency was used to derive a vertical profile of the jovian zonal wind speed. Due to the mission geometry, the Earth-based wind estimates are less sensitive to descent trajectory errors than estimates based on probe-orbiter Doppler measurements. The two estimates of wind profiles agree qualitatively; both show high wind speeds at all depths sampled.  相似文献   

Tinkering with life     

Rensberger B 《Science (New York, N.Y.)》1981,2(9):44-49

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Analysis of the volatile components in vanilla extracts and flavorings by solid-phase microextraction and gas chromatography   总被引：5，自引：0，他引：5  

Sostaric T  Boyce MC  Spickett EE 《Journal of agricultural and food chemistry》2000,48(12):5802-5807

The development and application of a solid-phase microextraction (SPME) method in the analysis of vanilla extracts and vanilla flavorings was studied. The SPME method was developed to be used in conjunction with gas chromatography mass spectrometry (GC-MS). The optimized SPME sampling parameters for the determination of the volatile components included a poly(acrylate) fiber, a 40-min sampling time at room temperature, and a 2-min desorption time. The reproducibility of the method was good, with a percent relative standard deviation between 2.5 and 6.4% for the target compounds. The data suggest that the origin of natural extracts can be readily determined from the GC profile and that differences exist between nature-identical and synthetic flavorings and the natural extracts. The method also has potential for identifying the type of vanilla extract/flavoring used to flavor food.  相似文献   

Maquiladora Employment Dynamics in Nuevo Laredo     

JESÚS CA AS  THOMAS M. FULLERTON  WM. DOYLE SMITH 《Growth and change》2007,38(1):23-38

ABSTRACT The Nuevo Laredo maquiladora sector has grown enormously during the last two decades. The short‐term time series characteristics of this portion of the regional economy are analyzed in an attempt to quantify the trends underlying this remarkable performance. Parameter estimation is accomplished via linear transfer function (LTF) analysis. Data are drawn from the January 1990–December 2000 sample period. Empirical results indicate that real wage rates, maquiladora plants, U.S. industrial activity, and the real exchange rate of the peso play significant roles in determining month‐to‐month fluctuations in maquiladora employment. Furthermore, sub‐sample forecast simulation exercises are conducted as an additional means for verifying model reliability. Empirical results indicate that the forecasts generated with the LTF model are less accurate than those associated with a simple random walk procedure for twelve separate step‐length periods.  相似文献   

Conference explores ethics of using animals for food.     

J Boyce 《Journal of the American Veterinary Medical Association》1991,199(3):318-319

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A one-way (non-rebreathing) valve suitable for use in gas analysis of exercising horses     

RF SLOCOMBE  WM BAYLY 《Australian veterinary journal》1993,70(4):151-152

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