排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
T. Winkel H. D. Bertero P. Bommel J. Bourliaud M. Chevarría Lazo G. Cortes P. Gasselin S. Geerts R. Joffre F. Léger B. Martinez Avisa S. Rambal G. Rivière M. Tichit J. F. Tourrand A. Vassas Toral J. J. Vacher M. Vieira Pak 《Journal of Agronomy and Crop Science》2012,198(4):314-319
Reviewing the situation of quinoa production in southern Bolivia, Jacobsen (2011, J. Agron. Crop Sci. 197: 390) argues that the booming export market has a negative effect on the environment and on the home consumption of quinoa, thereby leading to an environmental disaster in the region. In view of the scarcity of scientific knowledge on the rapid social and environmental dynamics in the region, we consider that Jacobsen’s review misrepresents the situation of quinoa production in southern Bolivia. Specifically, we argue that (i) the data presented by Jacobsen (2011, J. Agron. Crop Sci. 197: 390) do not support any drop in quinoa crop yield supposed to reflect soil degradation and (ii) his demonstration regarding home consumption of quinoa is ill‐founded from both a nutritional and a cultural point of view. We suggest that the diffusion of the arguments exposed by Jacobsen (2011, J. Agron. Crop Sci. 197: 390), because of their flaws, might have strong negative impacts on those concerned with sustainable food production and fair‐trade with developing countries. We conclude that, rather than reinforced agro‐technical controls on local farmers, the rising competition in the international quinoa market requires a shift towards an ethical economy and ethical research cooperation with quinoa producers. 相似文献
2.
A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. This paper summarizes its findings on the various agro-ecological features of the system and evaluates the system's functional aspects vis-a-vis the trends and developments in land use in the region over the past few centuries. The synergistic effects of tree cover on understorey grassland vegetation is discussed in terms of soil fertility build-up and favourable micro-climatic and hydrological features, and the potential use of this information in future research and development programmes to improve the dehesa system in the Mediterranean region is outlined. 相似文献
3.
Falush D Wirth T Linz B Pritchard JK Stephens M Kidd M Blaser MJ Graham DY Vacher S Perez-Perez GI Yamaoka Y Mégraud F Otto K Reichard U Katzowitsch E Wang X Achtman M Suerbaum S 《Science (New York, N.Y.)》2003,299(5612):1582-1585
Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade. 相似文献
4.
Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5 degreesC and that the 20th century has been the warmest of the past five centuries. The subsurface temperatures also indicate that Earth's mean surface temperature has increased by about 1.0 degreesC over the past five centuries. The geothermal data offer an independent confirmation of the unusual character of 20th-century climate that has emerged from recent multiproxy studies. 相似文献
5.
Blum JW Bruckmaier RM Vacher PY Münger A Jans F 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2000,47(1):43-60
Effects of feeding crystalline triglycerides (TGA), free fatty acids (FFA), and a starch-rich ration (STA) on metabolite and hormone concentrations in blood plasma were studied in high-yielding dairy cows over a 24-h period in week 9 and 19 of lactating. Energy-corrected milk production in the three groups was similar, but was lower in week 19 than in week 9. Energy and protein intakes were greater in week 9 than in week 19, but energy and protein balances in the three groups and in weeks 9 and 19 were similar. Plasma glucose and triglyceride concentrations were lower in week 9 than in week 19. In cows fed FFA, glucose concentrations were highest in week 9. Plasma triglyceride, phospholipid and cholesterol concentrations were highest, whereas beta-hydroxybutyrate concentrations were lowest in FFA-fed cows in weeks 9 and 19. Concentrations of insulin-like growth factor-I in week 19 were lower in cows fed TGA and FFA than in those fed the starch-rich ration. Post-prandial responses were usually greater following morning than afternoon meals. Fructosamine, albumin, urea, growth hormone, thyroxine, and 3,5,3'-triiodothyronine concentrations were similar in weeks 9 and 19 and were not influenced by dietary treatment or feeding times. In conclusion, there were distinct metabolic and endocrine effects of feeding TGA and FFA compared with STA and the concentrations as well as the 24-h changes of various metabolic and endocrine traits in weeks 9 and 19 of lactation were also different. 相似文献
6.
Scanlan SN Eagles DA Vacher NE Irvine MA Ryan CJ McKenzie RA 《Australian veterinary journal》2006,84(10):367-370
Four incidents of Duranta erecta (golden dewdrop, Sheena's Gold, Geisha Girl) poisoning affecting nine dogs and a cat produced drowsiness, hyperaesthesia and tetanic seizures in all affected animals with evidence of alimentary tract irritation (vomiting, gastric and intestinal haemorrhage, diarrhoea, melaena) in five dogs and the cat. Fruits and leaves were seen to be eaten by affected animals. Therapy was successful in three of the dogs. Repeated diazepam doses and, in some cases, additional pentobarbitone or propofol anaesthesia, were successful in controlling seizures. 相似文献
7.
Richard Joffre Jean Vacher Carlos de los Llanos Gilbert Long 《Agroforestry Systems》1988,6(1-3):71-96
A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa
system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. This paper
summarizes its findings on the various agro-ecological features of the system and evaluates the system's functional aspects
vis-a-vis the trends and developments in land use in the region over the past few centuries. The synergistic effects of tree
cover on understorey grassland vegetation is discussed in terms of soil fertility build-up and favourable micro-climatic and
hydrological features, and the potential use of this information in future research and development programmes to improve
the dehesa system in the Mediterranean region is outlined. 相似文献
8.
Modeling the potential for closing quinoa yield gaps under varying water availability in the Bolivian Altiplano 总被引:1,自引:0,他引:1
S. Geerts D. Raes M. Garcia C. Taboada R. Miranda J. Cusicanqui T. Mhizha J. Vacher 《Agricultural Water Management》2009,96(11):1652-1658
In the Bolivian Altiplano, the yields of rainfed quinoa are relatively low and highly unstable. We use a validated crop water productivity model to examine the potential of closing quinoa yield gaps in this region. We simulate the expectable yields under rainfed cultivation and under different deficit irrigation (DI) strategies using the AquaCrop model for the Northern, Central and Southern Bolivian Altiplano. Simulated DI scenarios include a reference strategy avoiding stomatal closure during all sensitive growth stages and allowing drought stress during the tolerant growth stages (DI0) and various restrictive deficit irrigation strategies (DIi) representing cases when water resources are limited. We obtain a logistic crop water production function for quinoa by plotting the seasonal actual evapotranspiration versus total grain yield. Due to the large scatter, this function only indicatively provides expectable yields. From the scenario analysis, we derive yield probability curves for the 3 agro-climatic regions. DI, without restriction in irrigation water during the drought sensitive growth stages, is able to close the yield gaps in the Northern, Central and Southern Bolivian Altiplano, and would guarantee a high and stable level of water productivity (WP). The yields of quinoa under rainfed cultivation during dry years are only 1.1, 0.5 and 0.2 Mg ha−1 in the Northern, Central and Southern Bolivian Altiplano, whereas under DI0 they are 2.2, 1.6 and 1.5 Mg ha−1, respectively. Under limited water availability for irrigation, these stable yield levels decrease, most drastically in the Southern Bolivian Altiplano. Below a minimum water availability of 600 m3 per ha and 700 m3 per ha in the Central and Southern Bolivian Altiplano, respectively, the application of DI for quinoa is not significantly effective and should be avoided to save valuable resources. The yield probability curves we derive can serve as input for stochastic economic analysis of DI of quinoa in the Bolivian Altiplano. 相似文献
9.
The hypothesis that the percentage of nonnative plant species inhabiting a landscape might be used as an integrated measure
of anthropogenic disturbance was explored in 26 diverse landscape parcels in Rhode Island. Nine correlates of anthropogenic
disturbance within, and immediately adjacent to the refuges were compared to two refuge-specific indices of relative nonnative
vascular plant species abundance. The percentage of the total vascular flora of each refuge that was nonnative was the Nonnative
Index for each refuge. The percentage of all nonnative species in the 26 refuges combined that occurred in a given refuge
was the Regional Nonnative Index for each refuge (nonnative species in each refuge divided by the nonnative species in all
26 refuges, times 100). The latter index measured how successful species from the finite pool of nonnative species present
in the region were at invading and colonizing a refuge. Of the 869 vascular plant species in all 26 refuges, 28% were nonnative.
The percentage of the vascular flora that was nonnative in each refuge varied from 2 to 50%. Few comparisons between correlates
of anthropogenic disturbance and Nonnative Indices were statistically significant, yet two of the nine correlates of anthropogenic
disturbance were highly related to Regional Nonnative Indices. Collectively, the correlates of anthropogenic disturbance accounted
for 39% of the variance in the Regional Nonnative Index for all species combined, and 56% of the variance in the Regional
Nonnative Index for tree species alone. The Regional Nonnative Index was also highly related to the richness of native plant
species. The hypothesis that the nonnative vascular plant diversity of a landscape can be used as a surrogate for the integrated
effects of anthropogenic disturbance was generally rejected by the analysis of our Nonnative Index, and supported by the analysis
of our Regional Nonnative Index. 相似文献
10.