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1.
JMIR Public Health Surveill ; 10: e48186, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38451620

RESUMO

BACKGROUND: Increasingly, survey researchers rely on hybrid samples to improve coverage and increase the number of respondents by combining independent samples. For instance, it is possible to combine 2 probability samples with one relying on telephone and another on mail. More commonly, however, researchers are now supplementing probability samples with those from online panels that are less costly. Setting aside ad hoc approaches that are void of rigor, traditionally, the method of composite estimation has been used to blend results from different sample surveys. This means individual point estimates from different surveys are pooled together, 1 estimate at a time. Given that for a typical study many estimates must be produced, this piecemeal approach is computationally burdensome and subject to the inferential limitations of the individual surveys that are used in this process. OBJECTIVE: In this paper, we will provide a comprehensive review of the traditional method of composite estimation. Subsequently, the method of composite weighting is introduced, which is significantly more efficient, both computationally and inferentially when pooling data from multiple surveys. With the growing interest in hybrid sampling alternatives, we hope to offer an accessible methodology for improving the efficiency of inferences from such sample surveys without sacrificing rigor. METHODS: Specifically, we will illustrate why the many ad hoc procedures for blending survey data from multiple surveys are void of scientific integrity and subject to misleading inferences. Moreover, we will demonstrate how the traditional approach of composite estimation fails to offer a pragmatic and scalable solution in practice. By relying on theoretical and empirical justifications, in contrast, we will show how our proposed methodology of composite weighting is both scientifically sound and inferentially and computationally superior to the old method of composite estimation. RESULTS: Using data from 3 large surveys that have relied on hybrid samples composed of probability-based and supplemental sample components from online panels, we illustrate that our proposed method of composite weighting is superior to the traditional method of composite estimation in 2 distinct ways. Computationally, it is vastly less demanding and hence more accessible for practitioners. Inferentially, it produces more efficient estimates with higher levels of external validity when pooling data from multiple surveys. CONCLUSIONS: The new realities of the digital age have brought about a number of resilient challenges for survey researchers, which in turn have exposed some of the inefficiencies associated with the traditional methods this community has relied upon for decades. The resilience of such challenges suggests that piecemeal approaches that may have limited applicability or restricted accessibility will prove to be inadequate and transient. It is from this perspective that our proposed method of composite weighting has aimed to introduce a durable and accessible solution for hybrid sample surveys.


Assuntos
Pesquisadores , Humanos , Probabilidade
2.
Front Plant Sci ; 13: 1003471, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36299789

RESUMO

The performance of existing rice-paddy weeding machines is not optimal. In this study, the influence of the installation angle of the weeding-wheel blade on cutting resistance and soil-slippage ability was analyzed. The optimal blade angle of the weeding wheel (i.e., the angle at which the resistance to the weeding wheel is minimal and the disturbance speed of the soil maximal) was shown to be< 20°; numerical simulation showed the actual optimal value to be 0°. Different weeding depths (30, 40, and 50 mm), rotation speed of weeding wheel (120, 180, and 240 r/min), and weeder forward speeds (0.3, 0.6, and 0.9 m/s) were used as test factors, and the rates of seedling injury and weeding were used as performance-evaluation criteria to optimize the machine in a secondary orthogonal-rotation combination test. Field experiments showed that the weeding wheel can exhibit optimal working performance under the operating conditions of weeding depth of 39 mm, rotation speed of 175 r/min, and forward speed of 0.6 m/s. The seedling injury and weeding rates were 4.4% and 88.2%, respectively, which were consistent with the numerically predicted results and met the agronomic requirements. This study provides a technical reference for the improvement of paddy-field weeding components.

3.
Materials (Basel) ; 14(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34885519

RESUMO

A hypothesis was put forward that a nano-modifying additive of micro silica, which had a beneficial effect on achieving a perfect structure of heavy concrete, can also be effectively used in lightweight fiber-reinforced concrete. The nano-modifying additives of micro silica application in manufacturing lightweight fiber reinforced concrete products and structures can significantly enchain their strength characteristics without increasing their mass and consequently improve their design characteristics. The purpose of the work was to increase the structural quality coefficients for all types of strengths of lightweight fiber-reinforced concrete due to its modification with micro silica. The effect of nano-modifying additives of micro silica on the strength characteristics of lightweight fiber reinforced concrete was studied. The optimal amount of micro silica addition was experimentally confirmed and established of 10% of the cement mass. The coefficients of constructive quality for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete modified with micro silica additives were calculated. The coefficient of constructive quality for tensile strength in bending of lightweight fiber reinforced concrete with additives was two and a half times higher than that of heavy concrete without additives and up to 37% higher than that of lightweight fiber-reinforced concrete without additives.

4.
J Food Sci ; 86(4): 1180-1200, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33682943

RESUMO

Micronutrient fortification of rice by extrusion is an effective strategy to enhance micronutrient levels within rice-consuming individuals. The success of extrusion-based fortification is associated with micronutrient retention, enhanced bioavailability, low postprocessing losses, prolonged storage stability, and minimal sensory changes. The success of an optimally fortified product is primarily reliant upon the compositional considerations, but many attributes of extrudates can be indebted to the processing parameters too. Hence, an exhaustive investigation of this technology has been taken-up here, emphasizing on the compositional parameters in association with process parameters, which influence the final quality attributes like nutrient stability, bioavailability, and sensory properties. Based on these attributes of the end product, a collected data have been presented here to bring out the optimal compositional requirements. These together with cooking processes, extrusion process parameters, and storage conditions will enable formulate a product with enhanced sensory acceptance, better retention during cooking and storage, improved texture, and acceptable color. This review will thus help to optimize a need-based product, its quality, and enhance benefits of fortified extruded rice products.


Assuntos
Tecnologia de Alimentos/métodos , Alimentos Fortificados , Micronutrientes , Oryza , Disponibilidade Biológica , Culinária , Qualidade dos Alimentos , Alimentos Fortificados/análise , Humanos , Micronutrientes/análise , Micronutrientes/farmacocinética , Oligoelementos/análise
5.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-906369

RESUMO

Objective:To explore the feasibility of replacing wood (or wood chips) with crop residues for culturing <italic>Armillaria gallica</italic> targeting the problems of forest resource destruction and increased cultivation cost caused by the extensive use of wood in <italic>Gastrodia elata</italic> cultivation, so as to reduce the cultivation cost of <italic>G. elata</italic>, promote the effective use of crop residues, and protect forest resources. Method:The growth situation of <italic>A. gallica</italic> in different media was observed, followed by the measurement of its growth rate using streaking method and the determination of total polysaccharide content of <italic>A. gallica</italic> by phenol-concentrated sulfuric acid colorimetric method. In order to further optimize the soybean straw cultivation medium, we carried out a four-factor three-level L<sub>9</sub>(3<sup>4</sup>) orthogonal assay on the ratio of main ingredients, sucrose content, inorganic salt content, and water content. Result:The comparison of growing states of <italic>A. gallica</italic> cultured in different media revealed that <italic>A. gallica</italic> in soybean straw medium began to grow since the fourth day of inoculation, and the mycelium grew well, with the growth rate being 0.352 cm·d<sup>-1</sup>, which was 1.48 times that in birch wood medium. The total polysaccharide content of <italic>A. gallica</italic> cultured in soybean straw medium was the highest, which was 39.260 mg·g<sup>-1</sup>, much higher than 17.028 mg·g<sup>-1</sup> of that cultured in birch wood medium. This demonstrated the obvious advantage of soybean straw medium, whose main ingredients were soybean straw and wheat bran at the ratio of 8:2, with the sucrose and inorganic salt content accounting for 1% and 0.5% of the main ingredients, respectively. When the water content reached 50%, the growth rate of <italic>A. gallica</italic> was maintained at 0.392 cm·d<sup>-1</sup>. Conclusion:This study has provided a basis for utilizing soybean straw instead of wood (or wood chips) as cultivation medium for <italic>A. gallica</italic>, thus better reducing the waste of forest resources and protecting the natural environment in the cultivation of <italic>G. elata</italic>.

6.
Nanomaterials (Basel) ; 10(6)2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32560355

RESUMO

The incorporation of nanomaterials on (bio)sensors based on composite materials has led to important advances in the analytical chemistry field due to the extraordinary properties that these materials offer. Nanodiamonds (NDs) are a novel type of material that has raised much attention, as they have the possibility of being produced on a large scale by relatively inexpensive synthetic methodologies. Moreover, NDs can present some other interesting features, such as fluorescence, due to surface functionalization and proved biocompatibility, which makes them suitable for biomedical applications. In addition, NDs can be customized with metallic nanoparticles (NPs), such as silver or gold, in order to combine the features of both. Raw NDs were used as modifiers of sensors due to the electrocatalytic effect of the sp2 and oxygenated species present on their surface. The aim of this research work is evaluating the applicability of NDs modified with silver (Ag@NDs) and gold (Au@NDs) nanoparticles for the development of a suitable (bio)sensing platform. A complete morphological and electrochemical characterization as a function of the prepared nanocomposite composition was performed in order to improve the electroanalytical properties of the developed (bio)sensors. In the present work, the optimal composition for Au@NDs present on the nanocomposite matrix is 3.5% and the one for Ag@NDs is 1%. Good results were obtained in the evaluation of the optimal composition towards hydrogen peroxide and glucose as a model analyte using a (bio)sensor based on graphite-epoxy-Ag@NDs (17:82:1).

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