Barley–legumes rotations for semi-arid areas of Lebanon     

S. K. Yau  M. Bounejmate  J. Ryan  R. Baalbaki  A. Nassar  R. Maacaroun 《European Journal of Agronomy》2003,19(4):599-610

In arid and semi-arid areas of West Asia and North Africa, including the northern Bekaa Valley of Lebanon, farmers have been increasingly practicing continuous barley cultivation. The objectives of the study were to (1) determine whether barley monoculture is unsustainable¹, (2) ascertain if barley and total dry matter yields can be increased and sustained by including a legume crop in the rotation, and (3) determine which barley–legume rotations are more productive. The trial was set up in a randomised complete block design with two replicates under rain-fed conditions in 1994–1995 at the Agricultural Research and Educational Center (33°56′ N, 36°5′ E, 995 m above sea level). Eight two-phase barley-based rotations were compared: barley in rotation with barley, lentil, common vetch, bitter vetch, common vetch for grazing, medics for grazing, common vetch for hay, and common vetch with barley for hay. Seed and straw were harvested from barley and legumes in the first four rotations. Relative to the trial mean, seed and straw yield under barley monoculture slumped in 1997–1998 and did not recover since then. Infestation of wild barley was a cause of this yield decline. Barley–legume rotations yielded 44–80% more barley grain and 27–53% more barley straw than the barley monoculture over the 6 years (1995–1996 to 2000–2001). Furthermore, in the legume phase, common and bitter vetch gave higher seed yield than barley monoculture. Thus, all barley–legume rotations, except barley–medics, yielded more total dry matter than barley monoculture on the basis of per rotation cycle. Among the barley–legume rotations, the barley-common vetch for seed rotation gave the highest and most stable dry matter yield. In conclusion, barley monoculture was unsustainable, but barley yields could be increased and sustained by including legumes in the rotation. Farmers in semi-arid areas of Lebanon should discontinue practicing barley monoculture and adopt a barley–legume, such as common vetch, rotation.  相似文献   

Identification of phenolic compounds in tissues of the novel olive cultivar hardy's mammoth     

Ryan D  Antolovich M  Herlt T  Prenzler PD  Lavee S  Robards K 《Journal of agricultural and food chemistry》2002,50(23):6716-6724

A methodological approach to phenolic profiling making extensive use of LC-MS with extracted ion chromatograms was applied to extracts of five different olive tissues: pulp, seed, stone, new-season leaves, and old-season leaves. Tissue extracts of the cultivars Hardy's Mammoth, Corregiola, Verdale, and Manzanillo were analyzed by HPLC with UV and ESI MS detection. Chromatograms of samples of green Hardy's Mammoth drupes, a uniquely Australian olive cultivar, were dominated by a large, broad peak. This peak was not attributable to oleuropein, which is usually the dominant phenolic compound in green olive fruit, but the phenolic compound I. This compound was isolated by semipreparative HPLC and characterized by 1D- and 2D-NMR. Extraction studies showed that the compound was not likely to be an artifact of an enzymatic degradation process. Tritium labeling studies were used to establish a possible relationship between the biosynthesis of I and oleuropein.  相似文献   

Reaction of proteins with formaldehyde in the presence and absence of sodium borohydride   总被引：1，自引：0，他引：1  

F Galembeck  D S Ryan  J R Whitaker  R E Feeney 《Journal of agricultural and food chemistry》1977,25(2):238-245

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Use of a population model to assess the impact of longline fishing on wandering albatross Diomedea exulans populations     

Coleen L. Moloney  John Cooper  Peter G. Ryan  W. Roy Siegfried 《Biological conservation》1994,70(3):195-203

An age-structured model of a wandering albatross Diomedea exulans population is developed to stimulate population trends over time, using demographic parameters from the population at Possession Island, Crozets, during 1968–1986. The simulation results portray a population decreasing at a rate of 2·29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5–10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30–50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trends; short-term (<20 year) estimates may not provide good indications of long-term trends.  相似文献   

Drought and fire suppression lead to rapid forest composition change in a forest-prairie ecotone   总被引：1，自引：0，他引：1  

Ryan D. DeSantis  Stephen W. Hallgren 《Forest Ecology and Management》2011,261(11):1833-1840

Altered fire regimes and increased drought can lead to major vegetation changes, especially in ecotones. A decrease in fire can lead to woody species encroachment in prairies and increasing forest stand density. The threat of global climate change raises questions about potential increases in the length, severity, and incidence of droughts substantially altering species composition. Re-measured upland forests in south-central North America's midcontinent forest-prairie ecotone exhibited major changes in woody species composition and structure over fifty years and successional trajectories appeared to favor invasive Juniperus virginiana L. over the previous dominant Quercus species. The objective of this study was to determine whether climate and fire exclusion affected the recruitment history of dominant woody species in these upland forests located near the xeric western edge of the eastern deciduous forest biome of North America. We removed cores and cross-sections from 992 J. virginiana, Quercus marilandica Münchh. and Q. stellata Wangenh. trees from eleven forest stands located across central and northwest Oklahoma, and determined their ages using standard dendrochronological methods. Recruitment of all species increased following a severe mid-20th century drought, but a rapid increase in J. virginiana recruitment and decrease in Quercus recruitment appeared to be linked to a decrease in fire. Future fire regime changes and increased drought due to global climate change could lead to widespread shifts from Quercus- to Juniperus- dominated forests and cause substantial changes to ecosystem services.  相似文献   

Robust two-stage approach to repeated measurements analysis of chronic ozone exposure in rats     

Beow?Yong?YeapEmail author  Paul?J.?Catalano  Louise?M.?Ryan  Marie?Davidian 《Journal of Agricultural, Biological & Environmental Statistics》2003,8(4):438-454

A robust two-stage approach is used to reanalyze the repeated measurements from an experiment of airway responsiveness in rats randomized to long-term exposure at four ozone doses. The concentration-response data generated for each rat may be represented as a hierarchical nonlinear model encompasing the sources of variation within and between individual profile for each rat, the conditional modeling approach can assess the adequacy of an assumed mean model, a fundamental advantage not intrinsic to marginal techniques. The two-stage population inference is based on the estimated individual parameters, thus maintaining an intuitive appeal to the toxicologists who traditionally have fitted a separate curve for each animal and then applied ANOVA to the summary statistics. However, we formally adjust the standard errors for the extra variability due to the initial estimation of the individual parameters and also allow for their within-rat correlation. The robust two-stage method appropriately down weights the a berrant responses arising sporadically within individualsand, more importantly, the rats which may be outlying relative to the usual population variation. The true effect of chronic ozone exposure, including a significant gender interaction, may be masked by a few rats which exert undue influence on the population estimates in a nonrobust analysis.  相似文献   

Conservation of argali Ovis ammon in western Mongolia and the Altai-Sayan     

Ryan L. Maroney 《Biological conservation》2005,121(2):231-241

Management of argali in Mongolia historically has been tied to improving biological research and anti-poaching activities within the framework of trophy hunting. Argali populations in protected areas, where trophy hunting does not occur, have received little attention, and conservation or management plans for these areas generally do not exist. In this study, results from interviews with pastoralists in Siilkhemiin Nuruu National Park in western Mongolia indicate that local people revere argali and are generally aware of and support government protections, but may not be inclined to reduce herd sizes or discontinue grazing certain pastures for the benefit of wildlife without compensation. Because past protectionist approaches to argali conservation in western Mongolia and the greater Altai-Sayan ecoregion have not achieved effective habitat conservation or anti-poaching enforcement, alternative management policies should be considered. Results from this study suggest local receptiveness to management programs based on community involvement and direct benefit.  相似文献   

Quantitative changes in phenolic content during physiological development of the olive (Olea europaea) cultivar Hardy's Mammoth     

Ryan D  Prenzler PD  Lavee S  Antolovich M  Robards K 《Journal of agricultural and food chemistry》2003,51(9):2532-2538

This investigation was designed to characterize phenolic metabolism of the olive cultivar, Hardy's Mammoth, by examining its constitutive tissues. The phenolic profiles of pulp, seed, stone, and new and old season leaves were monitored over two fruiting seasons, to investigate possible relationships between tissues and phenol content and to determine the impact of alternate fruit bearing. No major qualitative differences in phenolic composition were found between the various tissues; however, distinct differences between the tissues with respect to quantifiable phenols were established. Relationships between 2-(3,4-dihydroxyphenyl)ethyl (3E,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate ester, oleuropein, and hydroxytyrosol in pulp and leaf were identified and found to be related to alternate bearing. Concentrations of 5-caffeoylquinic acid in old season leaves differed dramatically between seasons, confirming earlier studies.  相似文献   

Mercury in soils,sediments, and clams from a North Carolina peatland     

Richard T. Di Giulio  Elizabeth A. Ryan 《Water, air, and soil pollution》1987,33(1-2):205-219

Mercury concentrations were measured in samples of peat soils, sediments and clams (Rangia cuneata) from a peatland region of the Albemarle-Panlico Peninsula of North Carolina. Total Hg concentrations in peat cores ranged from 40 to 193 ng g^?1 (dw); no depth-related trends were noted. Mercury concentrations in surface sediments from canals draining the peatlands and from the Pungo River that receives this drainage ranged from 8 to 20 ng g^?1 (dw). Selective extractions of these peat and sediment samples revealed that the bulk of the Hg was associated with organic matter-associated fractions (particularly humic/fulvic acid bound and organic-sulfide bound fractions). No Hg was detected in the relatively mobile and bioavailable water-soluble or ion-exchangeable fractions. Total Hg concentrations in the soft tissues of clams from the Pungo River ranged from 25 to 32 ng g^?1 (ww). No concentrations of methyl Hg above the detection limit of a 25 ng g^?1 were measured in soils, sediments, or clams. These data indicate that Hg concentrations in this region are at the low end of the distribution of levels reported for uncontaminated systems and that mining of these peatlands is unlikely to significantly elevate Hg concentrations in the receiving estuarine system.  相似文献   

The availability for the rat of methionine and cystine contained in dry bean seed (Phaseolus vulgaris)     

R J Evans  D H Bauer  K A Sisak  P A Ryan 《Journal of agricultural and food chemistry》1974,22(1):130-133

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