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161.
Camila Almeida Melo Lílian Karla de Oliveira Leonardo Fernandes Fraceto André Henrique Rosa 《Communications in Soil Science and Plant Analysis》2018,49(12):1530-1539
The objective of this work was to evaluate the adsorption of macronutrients calcium, potassium, magnesium, nitrogen, and phosphorus in two Brazilian tropical peat samples, investigating the effect of pH and determining the kinetics of the adsorption process. Two different Brazilian tropical peat samples were characterized using FTIR, TG, and SEM techniques. Different pH conditions were tested, as well as different mass concentrations of the peats. Differences in the chemical structures of the peat samples directly influenced the adsorptive capacities for the macronutrients. The adsorptive capacity for nitrogen was highest at pH 3, while the best adsorption of calcium and potassium was obtained at pH 6. The best fit to the data was provided by the pseudo-second-order model, which confirmed the rapid adsorption of calcium by both peats. 相似文献
162.
Analysis of tree interactions in a mixed Mediterranean pine stand using competition indices 总被引:1,自引:1,他引:0
Nicolás Cattaneo Andrés Bravo-Oviedo Felipe Bravo 《European Journal of Forest Research》2018,137(1):109-120
Studying species interactions in mixed forests allows us to assess their potential benefits and adapt current silvicultural tools developed in monospecific stands to multi-specific stands. We analyzed tree interactions in a Pinus halepensis Mill. and Pinus pinea L. mixed plantation using individual tree neighborhood models and competition indices that accounted for symmetric and asymmetric competition, to analyze whether the growth of each species was better explained by symmetric or asymmetric competition. We also split the competition indices into their intra- and interspecific forms, to test for competition effects on growth change based on competitor identity. Finally, we analyzed whether P. halepensis and P. pinea trees had different growth responses to competition. When calculating competition indices, we explored how spatial information and size of competitor trees contributed to the quantification of the process. Competition measurements were optimized to more precisely describe interactions. Results showed that the inclusion of competition indices generated important improvements in growth models. The main mode of competition was symmetric, which could be related to water restrictions typical of the Mediterranean climate. Considering competitor identity did not improve the growth models, while measurement without discriminating competitors by species generated more parsimonious models. P. halepensis and P. pinea trees had similar growth responses to competition, indicating that the two species cope with competition in similar ways. However, P. pinea showed lower average growth than P. halepensis in the period analyzed. Results suggest that preventing the onset of intense interspecific competition processes could help slow down the long-term replacement of P. pinea by P. halepensis and could have benefits for silvicultural management in systems with two species that share ecological niches but are capable of generating different goods and services. 相似文献
163.
Denise T. Fantoni Keila K. Ida André M. Gimenes Matheus M. Mantovani Jacqueline R. Castro Geni C.F. Patrício Aline M. Ambrósio Denise A. Otsuki 《Veterinary anaesthesia and analgesia》2017,44(4):710-718
Objective
To investigate whether pulse pressure variation (PPV) can predict fluid responsiveness in healthy dogs during clinical surgery.Study design
Prospective clinical study.Animals
Thirty-three isoflurane-anesthetized dogs with arterial hypotension during orthopedic surgery.Methods
Fluid challenge with lactated Ringer's solution (15 mL kg?1 in 15 minutes) was administered in mechanically ventilated dogs (tidal volume 10 mL kg?1) with hypotension [mean arterial pressure (MAP) < 65 mmHg]. The volume expansion was considered effective if cardiac output (CO; transesophageal Doppler) increased by ≥ 15%. Cardiopulmonary data were analyzed using two-way ANOVA, receiver operating characteristics (ROC) curves and Spearman coefficient; p < 0.05 was considered significant.Results
Effective volume expansion, mean ± standard deviation 42 ± 4% increase in CO (p < 0.0001) was observed in 76% of the dogs, resulting in a decrease in PPV (p < 0.0001) and increase in MAP (p < 0.0001), central venous pressure (CVP; p = 0.02) and ejection fraction (p < 0.0001) compared with before the fluid challenge. None of these changes occurred when volume expansion resulted in a nonsignificant CO increase of 4 ± 5%. No significant differences were observed in blood gas analysis between responsive and nonresponsive dogs. The increase in CO was correlated with the decrease in PPV (r = ?0.65; p < 0.0001) but absolute values of CO and PPV were not correlated. The PPV performance (ROC curve area: 0.89 ± 0.06, p = 0.0011) was better than that of CVP (ROC curve area: 0.54 ± 0.12) and MAP (ROC curve area: 0.59 ± 0.13) to predict fluid responsiveness. The best cut-off for PPV to distinguish responders and nonresponders was 15% (50% sensitivity and 96% specificity).Conclusions and clinical relevance
In mechanically ventilated, healthy, isoflurane-anesthetized dogs, PPV predicted fluid responsiveness to volume expansion, and MAP and CVP did not show such applicability. 相似文献164.
Shayne P. Bisetto Adriano B. Carregaro André E.S. Nicolai Thais F. Bressan William P. Leal Nathalia V. Xavier Diego F. Leal André F.C. Andrade 《Veterinary anaesthesia and analgesia》2017,44(3):594-599
Objective
To evaluate the effect of hyaluronidase on uptake, duration and speed of elimination of xylazine–tiletamine–zolazepam administered in the subcutaneous fat over the dorsal lumbar region of swine.Study design
Blinded, randomized, crossover study.Animals
Six healthy Landrace/Large White pigs weighing 132 ± 24 kg (mean ± standard deviation).Methods
Animals were administered xylazine (1 mg kg?1) and tiletamine–zolazepam (8 mg kg?1) (control treatment, CON), or xylazine–tiletamine–zolazepam at the same doses with hyaluronidase (400 IU) (treatment HYA). The treatments were administered into the dorsal lumbar adipose tissue, 2.5–3.0 cm laterally from the spinous process of the second lumbar vertebra. The latency, anesthesia and recovery periods were measured. Heart rate, noninvasive systolic, diastolic, and mean arterial pressures, respiratory rate, hemoglobin oxygen saturation and rectal temperature were recorded every 10 minutes for up to 50 minutes.Results
One animal in CON and one animal in HYA were responsive to stimulation and did not allow safe handling. No significant difference was found between treatments for latency (CON 11.3 ± 5.9 minutes, HYA 7.4 ± 5.1 minutes) and anesthesia (CON 53 ± 53 minutes, HYA 49 ± 38 minutes) periods. Recovery period was shorter in HYA (9 ± 6 minutes) than in CON (32 ± 16 minutes) (p < 0.05). Physiological variables were not significantly changed over time and were within accepted normal clinical limits for the species in both treatments.Conclusion and clinical relevance
Hyaluronidase (400 IU) administered into adipose tissue in pigs did not reduce the latency and duration of dissociative anesthesia, but was associated with faster recovery. 相似文献165.
Investor ownership or social investment? Changing farmland ownership in Saskatchewan,Canada 总被引:1,自引:0,他引:1
Annette Aurélie Desmarais Darrin Qualman André Magnan Nettie Wiebe 《Agriculture and Human Values》2017,34(1):149-166
There is growing recognition that land grabbing is a global phenomenon. In Canada, investors are particularly interested in Saskatchewan farmland, the province where 40 % of country’s agricultural land is situated. This article examines how the changing political, economic, and legal context under neoliberalism has shaped patterns of farmland ownership in Saskatchewan, between 2002 and 2014. Our research indicates that over this time, the amount of farmland owned by investors increased 16-fold. Also, the concentration of farmland ownership is on the rise, with the share of farmland owned by the largest four private owners increasing six-fold. Our methodology addresses some of the criticisms raised in the land grabbing literature. By using land titles data, we identified farmland investors and determined very precisely their landholdings thus allowing us to provide a fine-grained analysis of the actual patterns of farmland ownership. Although the article analyzes changes to farmland ownership in a specific historical, cultural and legislative context, it serves as the basis for a broader discussion of the values and priorities that land ownership policies reflect. Namely, we contrast an ‘open for business’ approach that prioritizes financial investment to one based on a land sovereignty approach that prioritizes social investment. The latter has greater potential if the aim is ecological sustainability and food sovereignty. 相似文献
166.
Paulo André Vidal Bandeira José Morais Pereira Filho Aderbal Marcos de Azevêdo Silva Marcílio Fontes Cezar Olaf Andreas Bakke Uilma Laurentino Silva Jucileide Barbosa Borburema Leilson Rocha Bezerra 《Tropical animal health and production》2017,49(5):1001-1007
This study evaluated the performance and carcass characteristics of lambs fed diets with increasing levels of Mimosa tenuiflora (Willd.) hay replacing Buffel grass (Cenchrus ciliaris). Twenty-eight Santa Inês male lambs with an average body weight (BW) of 20.3 ± 1.49 kg(mean ± SD) were allocated in individual stalls and distributed in a completely random design with four treatments (0, 20, 40, and 60 g/100 g total DM M. tenuiflora hay replacing Buffel grass hay in diet) with seven replications. M. tenuiflora hay at the level of 20% dry matter (DM) total replacing Buffel grass hay increased final weight (P = 0.006), total weight gain (P < 0.001), average daily weight gain (ADWG; P < 0.001), DM intake (P < 0.001), and feed efficiency (P < 0.001). Intake of crude protein, NDFap, ADFap, ash, ether extract, total and non-fibrous carbohydrates, and total digestible nutrients presented a positive quadratic effect with M. tenuiflora hay replacing Buffel grass hay and 40 g/100 g total DM level presented greater intake. There were positive quadratic effects by M. tenuiflora hay inclusion at 20 g/100 g total DM level on slaughtering weight (P = 0.005), hot carcass weight (P = 0.002), cold carcass weight (P = 0.002), empty body weight (P = 0.001), hot carcass yield (P = 0.002), cold carcass yield (P = 0.003), and increase linear on biological yield (P = 0.003). There was no influence on cooling weight loss (P = 0.284). M. tenuiflora hay may be included in lamb diets at amounts up to 20 g/100 g total DM substitution of Buffel grass hay because increase in the nutrients intake, growth performance, and carcass characteristics. 相似文献
167.
168.
Jeroen C.J. Groot André Jellema Walter A.H. Rossing 《European Journal of Agronomy》2010,32(1):112-119
Spatial planning aimed at multifunctional agriculture can be seen as a negotiation process on environmental, social and economic aspects of land use. Complexity arises due to the high number of stakeholders and due to the limited knowledge, which is often organized along disciplinary divides. This paper sets out from the premise that the role of agronomy in such land use planning processes can be strengthened by approaches that allow multi-objective and multi-scale evaluation of spatially explicit land use alternatives. We present an application of the explorative Landscape IMAGES framework, which employs the Differential Evolution optimization strategy and the concepts of Pareto optimality that are relatively easy to implement and to combine with spatially explicit indicator assessments. This technique yields a set of solutions, each representing a spatial configuration of hedgerows in a landscape along with the performance of the landscape in terms of Pareto rank and efficiency. The methodology was applied in a redesign of the structure of linear landscape elements in an agri-ecological zone in The Netherlands where 7 indicators representing ecological quality, landscape character and implementation costs were considered. The case study was developed in interaction with an NGO involved in landscape management planning and implementation.Spatial cohesion in the landscape was found to increase with larger total hedgerow length, but could also be improved without increasing the total length (and therefore costs of establishment and maintenance). Trade-offs existed with other objectives, since this change would involve replacing hedgerows currently positioned in the longitudinal direction (L) of the fields by hedgerows in the transversal direction (T). This change would compromise cultural heritage value as expressed in the L/T ratio, and it would require removal of mature hedgerows in some places and adding of new hedgerows elsewhere in the landscape, thereby increasing implementation costs.The approach was evaluated positively in terms of design validity, output validity and end-user validity. The role of the Landscape IMAGES framework in setting a research agenda to enhance the role of agronomy in multifunctional land use planning is discussed. 相似文献
169.
A real time PCR assay was developed for the detection of Chalara fraxinea in common ash. PCR primers and Taqman probes, based on the internal transcribed spacer region of the multi‐copy gene rDNA, were tested for specificity and sensitivity. The primers amplified an 81 bp fragment for C. fraxinea but did not amplify DNA from other Chalara species or from other fungi isolated from ash, whether pathogenic or saprophytic. The limit of detection was 5 pg of genomic DNA per PCR. Moreover, naturally‐infected samples were correctly diagnosed. A procedure for DNA extraction from woody tissues using an electric drill yielded DNA of an appropriate quality for real time PCR. This molecular method could be useful for routine analysis of this emergent pathogen and for epidemiological studies. 相似文献
170.
Alternative poultry production with special reference to free range broilers has increased significantly since the nineties
in many regions of the world. Numerous factors influence the productive performance of this type of broilers: genotype (namely
the use of naked neck animals), feeding and access to an outdoor area. The aim of this paper is to study the influence of
each of these factors on the productive performance of free range broilers under commercial rearing conditions. A total of
3200, day old chicks of both sexes from naked neck and normally feathered genotypes were used in this trial. After a joint
initiation phase, animals were divided into four different treatments with the combination of two concentrates (high vs low
energy content) and management (access to outside park or not). Experiment lasted a total of 12 weeks. Live weight date was
recorded weekly and a samples of animals from the trial were sacrificed at the age of 8, 10 and 12 weeks, when carcass characteristics
were determined. Besides sex, the only factor that seems to affect growth characteristics was genotype as naked neck animals
had poorer growth rates than normally feathered. No effect was detected on carcass yields and percentages of carcass components
for any of the variables. From the data presented in this trial the practises associated with free range production are of
relative inconsequence to the technical animal production parameters and can only be justified by a pressing need to differentiate
these products from standard poultry products in what concerns both welfare issues and meat characteristics. The results also
indicate that genetic material from alternative poultry production in Europe can be a useful option in poultry production
development projects in the tropics. 相似文献