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Morlin Carneiro Franciele Angeli Furlani Carlos Eduardo Zerbato Cristiano Candida de Menezes Patricia da Silva Gírio Lucas Augusto Freire de Oliveira Mailson 《Precision Agriculture》2020,21(5):979-1007
Precision Agriculture - Crop monitoring through remote sensing techniques enable greater knowledge of average variability in crop growth. Canopy sensors help provide information on the variability... 相似文献
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Early ventures into site-specific management involved fertilizer management decisions based on soil chemical properties characterized by some form of grid sampling. This is both labor and capital intensive and practitioners quickly began investigating other methods to get a measure of spatial variability. Aerial photographs, which were mainly used to evaluate and assess crop status, allow for the collection of whole-field data at relatively low cost. Our objective is to determine what relationships exist between aerial spectral data and intensive grid soil test results and whether this information can be used to improve future soil sampling strategies. Soil-test organic matter (OM) and Bray-1 P concentrations were measured on soil samples taken using an alternating 12.2- by 24.4-m grid in late March 1994 from a quarter section under center pivot irrigation. Spectral data were collected in the spring of 1996 prior to planting using a multispectral network of digital cameras. Correlations of brightness values from the blue, green, and NIR bands with both OM and Bray-1 P were significant, but relatively low. Normality tests revealed that brightness values for the spectral data sets were generally evenly distributed while those of the soil test OM and Bray-1 P were positively skewed. Many of the very high soil-test data values were due to past management. When those values were removed from the database, greater correlations between spectral data and soil test data were obtained. These results substantiated that aerial imagery can be used to improve sampling strategies, but it must be used in conjunction with existing knowledge and past management histories. 相似文献
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Brian Krienke Richard B. Ferguson Michael Schlemmer Kyle Holland David Marx Kent Eskridge 《Precision Agriculture》2017,18(6):900-915
Ground-based active sensors have been used in the past with success in detecting nitrogen (N) variability within maize production systems. The use of unmanned aerial vehicles (UAVs) presents an opportunity to evaluate N variability with unique advantages compared to ground-based systems. The objectives of this study were to: determine if a UAV was a suitable platform for use with an active crop canopy sensor to monitor in-season N status of maize, if UAV’s were a suitable platform, is the UAV and active sensor platform a suitable substitute for current handheld methods, and is there a height effect that may be confounding measurements of N status over crop canopies? In a 2013 study comparing aerial and ground-based sensor platforms, there was no difference in the ability of aerial and ground-based active sensors to detect N rate effects on a maize crop canopy. In a 2014 study, an active sensor mounted on a UAV was able to detect differences in crop canopy N status similarly to a handheld active sensor. The UAV/active sensor system (AerialActive) platform used in this study detected N rate differences in crop canopy N status within a range of 0.5–1.5 m above a relatively uniform turfgrass canopy. The height effect for an active sensor above a crop canopy is sensor- and crop-specific, which needs to be taken into account when implementing such a system. Unmanned aerial vehicles equipped with active crop canopy sensors provide potential for automated data collection to quantify crop stress in addition to passive sensors currently in use. 相似文献
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Hefti A Schlemmer I Sauter-Louis C Metzner M 《Berliner und Münchener tier?rztliche Wochenschrift》2012,125(7-8):315-325
The objective of this study was to compare the effects of three anaesthetic protocols with respect to possible pain-associated reactions: injection (INJE) with xylazine (0.2 mg/kg), ketamine (5 mg/kg) and local anaesthesia (procain 2%); a combination of injection and inhalation (KOMB) with xylazine (0.2 mg/kg), ketamine (2 mg/kg), and isoflurane (1.5-3.0 vol%); and inhalation with isoflurane (control group [o]) surgery. During the trial, the anaesthetic level was controlled, and signs of response to surgical stimulation or spontaneous movements, changes in heart rate, mean arterial pressure, plasma L-lactate and cortisol levels were recorded. The dosage of 5 mg ketamine/kg body mass was rarely sufficient to obtain surgical tolerance in group INJE. In order to attain surgical tolerance, it was necessary to administer an average of 8.4 mg ketamine/kg body mass. All animals of the INJEc/o groups started to show signs of spontaneous movements or response to surgical stimulation between five and twelve minutes after the last administration of ketamine. Signs of response to surgical stimulation at the time of skin incision were significantly most frequent (37%) in the INHAc group, while agitation or response to surgical stimulation at least once during the entire time of anaesthesia was significantly (p <0.01) most frequent in the INJEc group (100%). Changes in heart rate and mean blood pressure were not found to be related to surgical stress situations.Ten minutes after the incision, the highest increases in plasma cortisol levels above basal levels of the previous day were determined in the groups INJEc and INJEo (53.5 and 57.7 nmol/l, respectively). However, a significant increase of plasma cortisol levels between the previous day and ten minutes after incision was only found between INHAc and INHAo (30.1 versus 7.5 nmol/l, p < 0.01) but not in the other pairs of groups (INJEc/o and KOMBdc/o). Within the three experimental groups the increase of plasma cortisol levels between the previous day and ten minutes after incision was only significant between INJEc and KOMBc (53.5 versus 28.3 nmol/l, p < 0.01). Among the protocols tested in this study, the combination anaesthesia (KOMB) was associated with the least amount of pain-associated reactions by the calves. Therefore, this protocol should be used preferred to the other two protocols in order to minimise stress and pain for the animals as much as posssible. 相似文献
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Asvany O P PK Redlich B Hegemann I Schlemmer S Marx D 《Science (New York, N.Y.)》2005,309(5738):1219-1222
Protonated methane, CH5+, continues to elude definitive structural assignment, as large-amplitude vibrations and hydrogen scrambling challenge both theory and experiment. Here, the infrared spectrum of bare CH5+ is presented, as detected by reaction with carbon dioxide gas after resonant excitation by the free electron laser at the FELIX facility in the Netherlands. Comparison of the experimental spectrum at approximately 110 kelvin to finite-temperature infrared spectra, calculated by ab initio molecular dynamics, supports fluxionality of bare CH5+ under experimental conditions and provides a dynamical mechanism for exchange of hydrogens between CH3 tripod positions and the three-center bonded H2 moiety, which eventually leads to full hydrogen scrambling. The possibility of artificially freezing out scrambling and internal rotation in the simulations allowed assignment of the infrared spectrum despite this pronounced fluxionality. 相似文献
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Thomas Miedaner Franciele Caixeta Firas Talas 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(4):743-752
Fusarium culmorum is a haploid, worldwide occurring phytopathogenic fungus causing seedling blight, foot rot, and head blight of cereals and producing the mycotoxins deoxynivalenol (DON) and nivalenol (NIV) associated with health hazards in human and animals. The fungus reproduces asexually by conidiospores, a teleomorph is not known. We analyzed for the first time naturally occurring F. culmorum populations collected randomly in the field from infected wheat heads. A total of 186 isolates, from three populations from Germany (GER), Russia (RUS), Syria (SYR), as well as an international collection (INT) for comparison, were genotyped by 10 microsatellite (SSR, single sequence repeat) markers. A high genetic diversity within the three natural populations and the INT population as well was detected. About 90 % of multi-locus haplotypes (MLH) were unique across populations. The largest part of variance (81 %) was found within populations. Accordingly, population subdivision was low, fixation indices were significant only in one out of six comparisons, while estimates of gene flow (N m ) ranged from 0.8–4.8. Linkage equilibrium was revealed by the index of multi-locus association and the quotient of observed and expected variance when two linked markers were deleted. DON and NIV chemotypes grouped closely together in a principle coordinate analysis. SYR isolates were partly separated from GER and RUS populations. All population-genetic parameters were in a similar range compared to those for the sexually propagating species F. graminearum. In conclusion, results support the hypothesis of a recombining structure in F. culmorum as revealed by the high genetic variation within populations, a low fixation index and low gametic phase disequilibrium within populations. 相似文献
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The present study gives an overview on the whole mechanism of phytate degradation in the gut and the enzymes involved. Based on the similarity of the human and pigs gut, the study was carried out in pigs as model for humans. To differentiate between intrinsic feed phytases and endogenous phytases hydrolysing phytate in the gut, two diets, one high (control diet) and the other one very low in intrinsic feed phytases (phytase inactivated diet) were applied. In the chyme of stomach, small intestine and colon inositol phosphate isomers and activities of phytases and alkaline phosphatases were determined. In parallel total tract phytate degradation and apparent phosphorus digestibility were assessed. In the stomach chyme of pigs fed the control diet, comparable high phytase activity and strong phytate degradation were observed. The predominant phytate hydrolysis products were inositol phosphates, typically formed by plant phytases. For the phytase inactivated diet, comparable very low phytase activity and almost no phytate degradation in the stomach were determined. In the small intestine and colon, high activity of alkaline phosphatases and low activity of phytases were observed, irrespective of the diet fed. In the colon, stronger phytate degradation for the phytase inactivated diet than for the control diet was detected. Phytate degradation throughout the whole gut was nearly complete and very similar for both diets while the apparent availability of total phosphorus was significantly higher for the pigs fed the control diet than the phytase inactivated diet. The pathway of inositol phosphate hydrolysis in the gut has been elucidated. 相似文献
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Leandro Schlemmer Brasil André Felipe Alves de Andrade Bruno R. Ribeiro Zander A. Spigoloni Leandro Juen Paulo De Marco Jr 《水产资源保护:海洋与淡水生态系统》2021,31(12):1150-1157
- Despite the current rates of deforestation and the expected climatic changes, protecting species in their natural habitats is still the simplest, cheapest, and most effective way of safeguarding biodiversity. Here, the network of protected areas in the Brazilian Amazon was evaluated to assess its effectiveness in safeguarding species of Odonata.
- Ecological niche models were built to assess the suitability of the habitat for 503 Amazonian odonate species. Then, the effectiveness for the protection of odonate species of three classes of protected areas (strictly protected area, sustainable use area, and indigenous territory) was evaluated.
- Approximately 30% of the species are protected within the network of protected areas. These findings highlight the importance of protected areas for safeguarding most odonate species in the Amazon. For under-represented or gap species, additional resources are still needed for effective management and protection on some private properties, which need to set aside land for conservation. In this way, it is possible to preserve habitats for odonate species and guarantee their conservation in the Amazon.