2,612 research outputs found
Spatial Variability of Irrigated Corn Yield in Relation to Field topography and Soil Chemical Characteristics
Corn yield, topography and soil characteristics were sampled on a 26 ha area of a centre pivot irrigated cropland. The aim of the study was to determine relationships between corn yield, field topography and soil characteristics. The study was carried out in the Alentejo region of Portugal. Corn yield was measured with a combine harvester fitted with a grain-flow sensor and positioned by means of the Global Positioning System (GPS). A grid-based digital elevation model (DEM) with 1-m resolution was constructed and several topographic attributes were calculated from the DEM: the local slope gradient (S), profile curvature (Curv), specific catchments area (SCa), and a steady-state wetness index (W). Yield and
topographical attributes were computed for areas of radius 5, 10, 25 and 50 m, being considered its maximum, minimum, range and average values. The soil was systematically sampled with a mechanical probe for a total of 109 soil profiles used for analysis of the following soil superficial (<0.30 m) characteristics: extractable phosphorous (P2O5) and extractable potassium (K2O), soil pH, cation exchange capacity (CEC) and exchangeable bases. With centre pivot irrigation systems, the Wave50 index was shown to be useful for the identification of field areas in which low corn yields may be due to lack of water. At the same time, SCa was found to be useful for the identification of field areas in which low yields are due to
excess water and drainage problems. Higher positive correlation between pH, Ca and Curv were observed; calcium concentration was found on the transition areas between flat surfaces to concave ones, while lower
values were detected in convex and concave areas. Topographical indexes, namely Wave50, SCa and Curv, can be especially helpful in site-specific management for delineating areas where crop yields are more sensitive to extreme water conditions
Soil carbonation processes as evidence of tillage-induced erosion
Tillage-induced soil erosion or redistribution increases spatial variation of several soil properties and often reduces the
productive capacity of soil resources. Our objectives were to identify the extent of this type of erosion by observing the
changes in soil morphological properties in the field and analysing its possible effects on soil productivity. The study was
initiated in 2001 and conducted at two irrigated sites located approximately at Terena, Alandrol, 80 km east of Évora, Portugal.
They were planted to corn (Zea mays L.) during this study, but have a long history of agricultural use with a trend toward
increasing intensity in recent years. Soils in the field studies are classified mainly as Calcaric Regosols, Calcaric Cambisols,
Luvisols and small areas of Fluvisols. The amount of erosion was estimated by simulation and verified by describing the lithology and measuring soil carbonates. The presence of carbonates in the superficial Ap horizons of soils that were previously devoid of this compound, provide evidence of soil redistribution: (1) in soils derived from calcareous parent material, this is the
result of a re-carbonation process; (2) in soils derived from non-calcareous parent material the presence of carbonates in the
superficial Ap horizons results from a carbonation process. On both sites, A and B, approximately 17% of the soils sampled
were either carbonated or re-carbonated. Carbonation and re-carbonation of soil profiles confirmed that tillage had redistributed the soil-ploughing layer over time. Decreased corn yield was also observed as slope increase. If current agricultural practices are continued in this area, a decrease in soil quality and maximum yield on higher slopes can be expected
Solo e diferenciação do vinho à escala da exploração no sul de Portugal
Tendo em vista a avaliação da variabilidade espacial da produção e da qualidade do vinho à escala da parcela, apresentam-se resultados preliminares de um estudo em curso no Alentejo.
Observou-se uma correlação positiva entre a condutividade eléctrica aparente (ECa) do solo e a presença de solos com maior espessura de horizontes de textura fina, alguns desde a superfície e com argilas de maior CTC. Estes solos têm uma representação crescente nos talhões (T): 5, 2D, 10 e 12. Em 2012, esta sequência (excluindo T10) também correspondeu ao decréscimo do NDVI e da produção de uva e ao aumento da nota de prova do vinho
Image, satisfaction, destination and product post-visit behaviours: How do they relate in emerging destinations?
This study proposes a conceptual model that sheds light on how the destination image of emerging tourist destinations relates to tourism satisfaction and intention to subsequently recommend the place and purchase its products. Destination image is studied through three components – cognitive, affective, and unique. Unique image has been overlooked in previous research and few studies focus on its measurement. This study uses a new method of measuring it through text-mining of user-generated blog posts. Findings from a sample of 314 foreign visitors to Sofia, Bulgaria, reveal that the affective image influences tourist satisfaction and post-visit behaviour; the cognitive component has a significant effect on all the constructs, except for tourist satisfaction, whereas unique image only influences the intention to recommend and purchase destination country products. Joining together two streams of research, this study also argues that the intention to recommend a destination spot influences the intention to buy its products.This study proposes a conceptual model that sheds light on how the destination image of emerging tourist destinations relates to tourism satisfaction and intention to subsequently recommend the place and purchase its products. Destination image is studied through three components – cognitive, affective, and unique. Unique image has been overlooked in previous research and few studies focus on its measurement. This study uses a new method of measuring it through text-mining of user-generated blog posts. Findings from a sample of 314 foreign visitors to Sofia, Bulgaria, reveal that the affective image influences tourist satisfaction and post-visit behaviour; the cognitive component has a significant effect on all the constructs, except for tourist satisfaction, whereas unique image only influences the intention to recommend and purchase destination country products. Joining together two streams of research, this study also argues that the intention to recommend a destination spot influences the intention to buy its products.info:eu-repo/semantics/acceptedVersio
Coordinated Multi-Point MIMO Processing for 4G
The concept of cooperative Multiple-Input-Multiple-Output (MIMO), also referred
to as network MIMO, or as Coordinated Multi-Point Transmission (CoMP), was standardized in
3GPP Release 11. The goal of CoMP is to improve the coverage of high data rates and cell-edge
throughput, and also to increase system throughput. In this paper we analyze only the latter
scenario, using system level simulations in accordance with 3GPP guidelines. It is shown that the
use of joint coordinated multipoint transmission achieves additional throughput gains. However,
the gains depend on the scheduling type. This paper also indicates that the criterion of fairness
is an important parameter when the number of users is high
The role of brand equity in a new rebranding strategy of a private label brand
The purpose of this study is to understand the effects of the rebranding process on private label performance output, namely, on brand equity. More specifically, the study aims to investigate the performance of brand equity constructs (brand awareness, brand associations, perceived quality and brand loyalty) before and after the rebranding process.
A questionnaire was administered to 466 shoppers, who put forth their perceptions, of the brand’s image, before and after the rebranding. When analyzed altogether, brand equity constructs have not suffered significant changes, meaning that previously existing brand equity had successfully been transferred onto the new brand; however, new brand equity was not created in the process. Consumers do still associate the private label brand image with its previous brand identity. Nevertheless, their ability to easily identify the various brand tiers was improved with the new image. Consumers associate the rebranded image with being “innovative” and “original” and describe the previous image as “inexpensive” and “trustworthy”. Brand awareness and loyalty are the factors that relate the most to consumers’ perceptions of the brand before its rebranding.
This study contributes to the brand management literature by providing a new look into the under-researched problem of rebranding and brand equity, empirically validating the real-life market case.info:eu-repo/semantics/acceptedVersio
Interannual sub-aerial beach variability along a sector of the Tróia- Sines embayed coast
The comprehension of sub-aerial beach variability of sandy beaches is essential to describe and predict his behaviour after
extreme events (e.g. storms). Around the world coastline beach monitoring plans are established in order to characterize the
main morphodynamic changes at different spatial and temporal scales. Within this scope, four field surveys (19th to 28th May
2009; 30th October to 10th November 2009, 21th to 30th May 2010 and 14l to 21 April 2011), using a new coastal survey
system named INSHORE system(Differential Global Positioning System) [1], were conducted along the Tróia-Sines
embayed beach (INSHORE project -PTDC/AMB/73169/2006).
The interannual variability of the sub-aerial beach topography along the Tróia-Sines embayed coast for the first three field
surveys were analysed considering the DEM (Digital Elevation Model) analysis regarding the: alongshore coastline
configuration; subaerial beach width; beach profile configuration and volumetric changes.
The results points to the definition of eight main coastline sectors very similar to the results previously described by [2].
Although a general north-south increasing beach width trend can be observed, [3] one of these main sectors, Sector 6,
presents a significant variation of the beach width and beach profile configuration. This sector was selected to describe the
morphodynamic pattern responsible for the sediment accommodation (beach width, and profile configuration) during the
studied period.
The subtraction between the three DEMs points to the importance of the beach width variation that describes the landward
or seaward subaerial beach displacement. Although this might affect the beach width, this variable should not be taken as
the unique one to describe the shoreline change. In fact, this parameter does not describe the beach variability regarding
the profile configuration (e.g. berm width and sediment accommodation). According to our results the volumetric changes
are strictly related to the beach width variation but the profile configuration has a particular role in the final budget analysis.
The proxies that were used (+2m, +3.4m and +4,3m MSL elevation contours) and the relation between the beach width and
subaerial beach volume, has given high correlation values. These results proved that not only the MHW (mean high water)
used by others authors [4] can be defined as a proxy to describe the shoreline evolution, but also other morphodynamic
meaningful contour elevations can give reliable results
SLaMA-URM method for the seismic vulnerability assessment of UnReinforced Masonry structures: Formulation and validation for a substructure
An analytical procedure based on the SLaMA (Simplified Lateral Mechanism Analysis) method is proposed for the seismic vulnerability assessment of UnReinforced Masonry (URM) structures. The procedure considers an equivalent frame discretization for the structure (pier, spandrel, and joint elements) and includes: (i) the evaluation of moment‒rotation capacity curves at each pier-spandrel subassembly; (ii) the assessment of the hierarchy of strength in each subassembly; and (iii) the calculation of the structure capacity curve according to the expected failure mechanism. Validation of the proposed SLaMA-URM procedure is achieved in a one-story URM substructure tested under lateral cyclic loading. The analytical predictions are compared with numerical ones from a 2D continuous finite element (FE) model based on a macro-modelling strategy. The flexural capacity of the components is estimated using a monolithic beam analogy, and the results compared with those from traditional sectional analysis. The influence of the substructure geometry on the hierarchy of strength at the subassembly and global levels is investigated. An analytical formulation of the pier-spandrel joint strength is also proposed to be considered in the assessment of the hierarchy of strength. The method is validated for a one-story substructure subjected to lateral in-plane loading. Results, in terms of crack patterns and capacity curves, are in relatively good agreement with the experimental and FE results, even when a bilinear curve approximation is used. The potential of the SLaMA-URM method for the seismic assessment of URM buildings is demonstrated, whose application to a larger URM structure is planned as a subsequent study
Interference Suppression consisting of Pre-Distortion Filtering and Beamforming with joint Transmit Diversity
The purpose of the current paper is to combat both the MAI and fading, in the downlink direction. First, we propose a new pre-distortion (PD) filtering technique, which can be used to combat the Multiple Access Interference (MAI), combined the Selective Transmit Diversity (STD) for high data rate transmissions over frequency selective Rayleigh fading channels. The proposed PD scheme considers a RAKE in the receiver. By pre-distorting the signals to be transmitted by the Base Station (BS) with a Minimum Variance (MV) algorithm, the orthogonality between the desired signal and all interfering signals can be improved. With the PD, the increase in performance is achieved with a small increase in power processing at the BS, avoiding any need to increase complexity at the Mobile Station (MS). Second, we consider a combination of the Beamforming (BF) and Transmit Diversity (TD). The performances of space-time transmit diversity (STTD) in combination with STD, beamforming (BF) and beam selective transmit diversity (BSTD), which is a composite scheme of STD and BF, have been studied at the system level using BER as performance index It is shown that the use of the proposed PD filter, alone or combined with the STD tends to achieve a performance improvement over the corresponding schemes without PD. A good alternative scheme for BSTD, BF and STTD+STD is the use of PD filter, which corresponds to a decrease in complexity
Companion animals-An overlooked and misdiagnosed reservoir of carbapenem resistance
Research Areas: Infectious Diseases ; Pharmacology & PharmacyABSTRACT - The dissemination of antimicrobial-resistance is a major global threat affecting both human
and animal health. Carbapenems are human use β-lactams of last resort; thus. the dissemination of
carbapenemase-producing (CP) bacteria creates severe limitations for the treatment of multidrugresistant bacteria in hospitalized patients. Even though carbapenems are not routinely used in
veterinary medicine, reports of infection or colonization by carbapenemase-producing Enterobacterales in companion animals are being reported. NDM-5 and OXA-48-like carbapenemases are
among the most frequently reported in companion animals. Like in humans, Escherichia coli and
Klebsiella pneumoniae are the most represented CP Enterobacterales found in companion animals,
alongside with Acinetobacter baumannii. Considering that the detection of carbapenemase-producing
Enterobacterales presents several difficulties, misdiagnosis of CP bacteria in companion animals
may lead to important animal and public-health consequences. It is of the upmost importance to
ensure an adequate monitoring and detection of CP bacteria in veterinary microbiology in order
to safeguard animal health and minimise its dissemination to humans and the environment. This
review encompasses an overview of the carbapenemase detection methods currently available, aiming to guide veterinary microbiologists on the best practices to improve its detection for clinical or
research purposes.info:eu-repo/semantics/publishedVersio
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