Persistent effect of organic matter pulse on a sandy soil of semiarid Patagonia     

Marina González Polo  Esteban Kowaljow  Elisa Castán  Ophelie Sauzet  María Julia Mazzarino 《Biology and Fertility of Soils》2015,51(2):241-249

  相似文献   

Detection of bovine viral diarrhea virus (BVDV) in seropositive cattle     

Gogorza LM  Morán PE  Larghi JL  Seguí R  Lissarrague C  Saracco M  Braun M  Esteban EN 《Preventive veterinary medicine》2005,72(1-2):49-54; discussion 215-9

Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three non-vaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response.  相似文献   

Factors Affecting Fertility According to the Postpartum Period in Crossbred Dual-Purpose Suckling Cows in the Tropics     

Perea-Ganchou F  Soto Belloso E  González Stagnaro C  Soto Castillo G  Hernández Fonseca H 《Tropical animal health and production》2005,37(7):559-572

To determine the relationship between first service conception rate (FSC) and the postpartum period (PP), 6160 calvings from 2250 crossbred dual-purpose cows were analysed. The effects of breed predominance (BT: Bos taurus and BI: Bos indicus), season of service (dry, intermediate and humid), parity (1 or 2 and more), agroecological region (Sub-humid and Dry Tropical Forest) and milk production were studied. The postpartum period was grouped according to the calving–first service interval as G1 ≤ 60 days (n = 1889); G2 > 60 ≤ 90 days (n = 1436); G3 > 90 ≤ 120 days (n = 1030); and G4 > 120 days (n = 1805). Data were analysed by chi-squared test. The overall mean for FSC was 58.2% and was lower in G1 (p < 0.01). All PP showed a breed effect on FSC, with mean values of 61.6% and 53.3% for BI and BT, respectively. Season of service also affected FSC, which was significantly lower during the humid period: 51.2% versus 57.4% and 61.5% for the intermediate and dry periods (p < 0.01), respectively. Parity and environmental effects were not observed on FSC. Levels of milk yield did influence the FSC, which decreased from 66.7% and 61.0% for milk yields of < 1500 kg and between 1501 and 2000 kg to 46.0% in milk yields > 2000 kg (p < 0.01).  相似文献   

Effect of industrial dehydration on the soluble carbohydrates and dietary fiber fractions in legumes     

Martín-Cabrejas MA  Aguilera Y  Benítez V  Molla E  López-Andréu FJ  Esteban RM 《Journal of agricultural and food chemistry》2006,54(20):7652-7657

The effects of soaking, cooking, and industrial dehydration treatments on soluble carbohydrates, including raffinose family oligosaccharides (RFOs), and also on total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble (SDF) dietary fiber fractions were studied in legumes (lentil and chickpea). Ciceritol and stachyose were the main alpha-galactosides for chickpea and lentil, respectively. The processing involved a drastic reduction of soluble carbohydrates of these legumes, 85% in the case of lentil and 57% in the case of chickpea. The processed legume flours presented low residual levels of alpha-galactosides, which are advisable for people with digestive problems. Processing of legumes involved changes in dietary fiber fractions. A general increase of IDF (27-36%) due to the increase of glucose and Klason lignin was observed. However, a different behavior of SDF was exhibited during thermal dehydration, this fraction increasing in the case of chickpea (32%) and decreasing in the case of lentil (27%). This is probably caused by the different structures and compositions of the cell wall networks of the legumes.  相似文献   

Monthly variation of fertility and oestrus frequency in crossbred dual-purpose cows in three agroecological areas of the South American tropics     

Perea F  Soto E  Hernández H  González D  Palomares R  De Ondiz A  González C 《Tropical animal health and production》2006,38(4):353-363

The aim of this study was to examine the monthly variation of the first service conception (FSC) and oestrus frequency (OF) from 8308 artificial inseminations (AI) of 2960 crossbred dual-purpose cows on three commercial farms with improved management located in the Maracaibo Lake Basin, Venezuela. The effects of month of the year, agroecological area (from dry tropical forest to sub-humid tropical forest on the three farms), predominant breed (BT, Bos taurus; BI, Bos indicus), and season (December–April}; May–August; and September–November) were considered. Data were analysed using logistic regression (FSC) and GLM (OF) from SAS. The mean FSC was 55.4% overall and 48.7%, 57.0% and 58.3% for farms A, B and C, respectively (p < 0.01). Within the three agroecological areas (farms A, B and C), the FSC was highest during the cooler and drier months of the year (season 1), while the lowest FSC was obtained during the months of highest rainfall and humidity (season 3) (53.3% vs 37.4%; 58.5% vs 49.0% and 63.0% vs 52.3% on farms A, B, C, respectively; p < 0.01). In the three studied farms, OF was higher during the first 4 months of the year; with a diminishing trend towards the end of the year (p % 0.05). In general, BI cows had a higher FSC than BT cows, especially during the second half of the year, when environmental conditions were characterized by higher rainfall and humidity with lower wind velocity (58.8%^a 55.5%^b and 46.4%^c in season 1, 2 and 3 respectively; ^{a, b, c} p < 0.01).  相似文献   

Ethnicity and conflict: theory and facts     

Esteban J  Mayoral L  Ray D 《Science (New York, N.Y.)》2012,336(6083):858-865

Over the second half of the 20th century, conflicts within national boundaries became increasingly dominant. One-third of all countries experienced civil conflict. Many (if not most) such conflicts involved violence along ethnic lines. On the basis of recent theoretical and empirical research, we provide evidence that preexisting ethnic divisions do influence social conflict. Our analysis also points to particular channels of influence. Specifically, we show that two different measures of ethnic division--polarization and fractionalization--jointly influence conflict, the former more so when the winners enjoy a "public" prize (such as political power or religious hegemony), the latter more so when the prize is "private" (such as looted resources, government subsidies, or infrastructures). The available data appear to strongly support existing theories of intergroup conflict. Our argument also provides indirect evidence that ethnic conflicts are likely to be instrumental, rather than driven by primordial hatreds.  相似文献   

Perspectives in dryland restoration: approaches for climate change adaptation     

V. Ramón Vallejo  Athanasios Smanis  Esteban Chirino  David Fuentes  Alejandro Valdecantos  Alberto Vilagrosa 《New Forests》2012,43(5-6):561-579

Reforestation efforts in dryland ecosystems frequently encounter drought and limited soil productivity, although both factors usually interact synergistically to worsen water stress for outplanted seedlings. Land degradation in drylands (e.g. desertification) usually reduces soil productivity and, especially, soil water availability. In dry sub-humid regions, forest fires constitute a major disturbance affecting ecosystem dynamics and reforestation planning. Climate change projections indicate an increase of drought and more severe fire regime in many dryland regions of the world. In this context, the main target of plantation technology development is to overcome transplant shock and likely adverse periods, and in drylands this is mostly related to water limitations. In this paper, we discuss some selected steps that we consider critical for improving success in outplanting woody plants, both under current and projected climate change conditions including: (1) Plant species selection, (2) Improved nursery techniques, and (3) Improved planting techniques. The number of plant species used in reforestation is increasing rapidly, moving from a reduced set of well-known, easy-to-grow, widely used species, to a large variety of promising native species. Available technologies allow for reintroducing native plants and recovering critical ecosystem functions for many degraded drylands. However, climate change projections introduce large uncertainties about the sustainability of current reforestation practices. To cope with these uncertainties, adaptive restoration approaches are suggested, on the basis of improved plant quality, improved techniques for optimizing rain use efficiency in plantations, and exploring native plant species, including provenances and genotypes, for their resilience to fire and water use efficiency.  相似文献   

Magnetic resonance imaging of canine mast cell tumors     

Pokorny E  Hecht S  Sura PA  LeBlanc AK  Phillips J  Conklin GA  Haifley KA  Newkirk K 《Veterinary radiology & ultrasound》2012,53(2):167-173

Mast cell tumors (MCT) are the most common cutaneous tumors in dogs. Our purpose was to describe the magnetic resonance (MR) imaging characteristics of cutaneous MCT and to identify imaging characteristics that allow differentiation of metastatic from normal lymph nodes. Eight dogs with a total of nineMCT were imaged as were their presumed draining and associated contralateral lymph nodes. The signal intensity of tumors and lymph nodes was compared to adjacent musculature. On T2-W images, 7/9 MCT were hyperintense to muscle and 2/9 were isointense. On T1-W images, 8/9 MCT were isointense and 1/9 were mildly hypointense. All tumors were strongly contrast enhancing; 5/9 were homogeneous and 4/9 heterogeneous in their enhancement patterns. Six lymph node pairs were included in the evaluation (five sentinel lymph nodes with metastases, one without, and six contralateral lymph nodes). Metastatic lymph nodes were significantly larger than their contralateral lymph nodes (P = 0.039). All lymph nodes were isointense on T1-W images and hyperintense on T2-W images. 5/5 metastatic and 2/7 normal lymph nodes were heterogeneously T2-hyperintense. All lymph nodes were moderately to strongly contrast enhancing. 4/5 metastatic and 2/7 normal lymph nodes had heterogeneous enhancement patterns. While heterogeneity was more common in metastatic than in normal lymph nodes, this difference was not significant (P = 0.058 for T2-W images; P = 0.234 for postcontrast images). MR imaging may be useful in the presurgical evaluation and clinical staging of cutaneous MCT.  相似文献   

Antioxidant Activity Evaluation of New Dosage Forms as Vehicles for Dehydrated Vegetables     

María Dolores Romero-de Soto  Patricia García-Salas  Salvador Fernández-Arroyo  Antonio Segura-Carretero  Francisco Fernández-Campos  Beatriz Clares-Naveros 《Plant foods for human nutrition (Dordrecht, Netherlands)》2013,68(2):200-206

A dehydrated vegetables mixture loaded in four pharmaceutical dosage forms as powder, effervescent granulate, sugar granulate and gumdrops were investigated for their antioxidant capacity using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging capacity assay, oxygen radical absorbance capacity assay and ferric reducing antioxidant potential assay. Total phenolic content of dehydrated vegetables powder mixture was also measured by the Folin-Ciocalteu method, so as to evaluate its contribution to their total antioxidant function. The effect of different temperatures on stability of these systems after 90 days storage was also evaluated. These formulations presented strong antioxidant properties and high phenolic content (279 mg gallic acid equivalent/g of sample) and thus could be potential rich sources of natural antioxidants. Antioxidant properties differed significantly among selected formulations (p?<?0.05). Generally, the losses were lower in samples stored under refrigeration. To interpret the antioxidant properties a kinetic approach was performed. Degradation kinetics for the phenolic content and antioxidant capacity followed a zero-order function. Effervescent granulate was the formulation which underwent faster degradation. Contrary, sugar granulate and gumdrops were much more slowly. Time required to halve the initial amount of phenolic compounds was 589?±?45 days for samples stored at 4?º C, and 312?±?16 days for samples stored at room temperature. These developed dosage forms are new and innovative approach for vegetable intakes in population with special requirements providing an improvement in the administration of vegetables and fruits.  相似文献   

A new method to trace colloid transport pathways in macroporous soils using X‐ray computed tomography and fluorescence macrophotography     

Diego Soto‐Gmez  Paula Prez‐Rodríguez  Laura Vzquez Juíz  Jos E. Lpez‐Periago  Marcos Paradelo Prez 《European Journal of Soil Science》2019,70(3):431-442

  相似文献