Modern Methodological Approaches to Sample Preparation for the Determination of Trace Elements in Food Products and Plant Raw Materials

Introduction. Various copper compounds are most widely used as plant protection agents in agriculture. From a hygienic point of view, information on excessive accumulation of copper in plants related to the use of a specific formulation of copper-containing pesticides is of interest. Our objective was to assess feasibility of increasing statistical significance of results of determining low residue levels of a copper-containing pesticide in apple samples by flame atomic absorption spectrometry using a high-resolution spectrometer in combination with developed approaches to sample preparation of plant-based foods, including homogenization with dry ice and microwave mineralization. Materials and methods: We analyzed 30 samples of apples collected in three different agro-climatic zones by flame atomic absorption spectrometry and electrothermal atomization atomic absorption spectrometry. Both methods were validated on 10 samples with added copper at levels 1-5 of the lower limit of quantitation. A statistical calculation was performed based on a simple Student’s test to assess the significance of differences between the results of measurements by flame and electrothermal techniques. Homogeneity of variances was estimated using the Fisher test to clarify the possibility of comparing two data sets. Results: The use of a technique of cryo-grinding and microwave decomposition in a microwave reactor in combination with a high-resolution continuum source atomic absorption spectrometry demonstrated a decrease in scattering and the limit of detection and better repeatability in the analysis of parallel samples. Results of statistical calculations confirmed the homogeneity of variances in data samples obtained for electrothermal and flame techniques, and the further Student’s t-test showed insignificant differences between the results of measurements obtained by FAAS and ET-AAS. Conclusion: Our findings prove that modern methods of sample preparation in combination with highly sensitive equipment allow a significant reduction in the limit of detection and scattering of test results.

Observations on the Potential of an Endophytic Fungus Associated with Cacao Leaves against Phytophthora palmivora

A study was conducted to test the pathogenicity of an endophytic fungus associated with asymptomatic cacao leaves, to determine its identity through cultural, morphological and molecular characterization, and to evaluate itsantagonistic ability vs. Phytophthora palmivora causing cacao black pod rot disease. Experiments were carried out under laboratory and shade house conditions. Homogeneity of variances and normal data distribution were determined using Bartlett’s and Shapiro–Wilk tests, respectively. Inoculation of the endophyte in healthy cacao seedlings and pods at 5 × 105 to 1 × 106 conidia per mL by spraying resulted in asymptomatic infections. The endophyte was recovered from artificially inoculated tissues 14 and 26 days after inoculation (DAI) (UF18 seedlings), and at 10 (K9 seedlings) and 14 DAI from cacao pods. The endophyte was identified as Colletotrichum siamense based on its cultural, morphological and molecular characteristics. In vitroanti-pathogen assays showed that C. siamense had the potential to limit pathogen growth by antibiosis. At 3, 5 and 7 days after incubation period (DAIP), growth of the pathogen in co-cultivation with the endophyte measured 60.0, 70.0 and 71.0 mm, respectively, which wasconsiderably lower than the growth of the pathogen alone.

Analysis of Reverse Logistics Functions of Small and Medium Enterprises: The Evaluation of Strategic Business Operations

Today, reverse logistics (RL) is still considered as an emerging field, despite the fact that it has drawn increasing attention over the last decade and now there is a growing interest in the domain of RL than ever before. Although many firms have yet to recognize the capability of effective RL, some firms have realized the strategic importance of RL and initiated deployment of thoughtful investments in functions and systems of their RL practices. Nowadays, RL is considered as a crucial activity for the survival of companies. This article deliberates on RL, cost optimization (CO) and return strategies (RS), along with their implications for small and medium enterprises (SMEs). Information is collected from 420 SMEs using judgemental sampling. On the basis of the literature, the framework of the study is proposed and further analysis is performed using a reliability assessment, normality and adequacy examination, evaluation of the homogeneity of variances, development of the structural model with coefficients and testing of the model through fitment analysis. The outcome of the study highlights that there is no direct causal association between RL and CO; however, there is an indirect association through RS. It is observed that there is a significant cause-and-effect association between RL and RS, as well as a significant cause-and-effect association between RS and CO, in SMEs.

Pengaruh Latihan Target Cone dan Ban terhadap Hasil Ketepatan Shooting Jarak 9 Meter pada Atlet Petanque Di Kabupaten Brebes

Petanque adalah salah satu bentuk permainan olahraga yang bertujuan untuk melemparkan bola besi dekat ke arah bola kayu. Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh..latihan target cone dan ban terhadap hasil ketepatan shooting jarak 9..meter pada Atlet petanque Brebes. Dalam penelitian ini jenis penelitian yang digunakan yaitu penelitian kuantitatif dengan metode penelitian Quasi Experimental Design. Sedangkan desain penelitian menggunakan Two Grup Pretest-Posttest Desaign. Sampel yang digunakan sebanyak 8 Atlet petanque Kabupaten Brebes. Hasil penelitian ini menunjukan bahwa meningkatannya latihan target cone dan ban terhadap hasil ketepatan shooting jarak 9 meter bedasarkan hasil dari hitung tabel Test of Homogeneity of Variances diperoleh nilai Sig = 0.069. Homogenitas di Sig sebesar 5% atau 0.05, terlihat bahwa nilai Sig 0.069 > 0.05, maka untuk keseluruhan variabel hipotesi telah di terima. Kesimpulan dari penelitian ini ada pengaruh latihan target cone dan ban terhadap hasil ketepatan shooting jarak 9 meter pada Atlet.petanque di.Kabupaten Brebes.

Eucalypt Clonal Hybrid Influences the Carbon Amount of Below-Ground Biomass in Oxisol, Brazil

The objective of this study was to evaluate whether there is an influence of different clonal hybrids of Eucalyptus urophylla on the carbon concentration and amount in below-ground biomass in trees cultivated in Oxisol, Brazil. Stumps and roots of three different eucalypt hybrid clones, AEC 0144, AEC 0223, and VM01, were selected, weighed immediately after being removed from the ground, and sampled for carbon determination and moisture content at the laboratory. The Shapiro-Wilk and Bartlett tests were used to evaluate data distribution and the homogeneity of variances, respectively. Analysis of variance (ANOVA) complemented by the Scott-Knott test was used to evaluate the effects of specie/hybrid on the below-ground biomass (dry matter) and carbon amount per stump. The hybrid type of Eucalyptus urophylla does not influence the carbon concentration; however, there is a difference in below-ground biomass production and carbon amount with it being higher for Eucalyptus urophylla × Eucalyptus camaldulensis when compared to the species Eucalyptus urophylla and hybrid Eucalyptus urophylla × Eucalyptus grandis.

Characterizing the amount and variability of intramuscular fat deposition throughout pork loins using barrows and gilts from two sire lines

The objective was to determine the amount and variability of intramuscular fat (IMF) in a pork loin attributable to anatomical chop location, sex, and sire line. Pigs were sired by commercially available terminal Duroc boars selected for meat quality (MQ; n = 96) or lean growth (LG; n = 96) and equally split between barrows and gilts. After slaughter and fabrication, bone-in chops were removed from four locations of each left-side loin (A = 6th rib, B = 10th rib, C = last rib, and D = 4th lumbar vertebrae). An adjacent pair of chops from each location was collected and evaluated for visual color and marbling, subjective firmness, moisture and extractable lipid (IMF) (anterior chop), and Warner–Bratzler shear force (posterior chop). Data were analyzed using the MIXED procedure of SAS as a split-plot design. Homogeneity of variances was tested on raw data using Levene’s test of the GLM procedure and found to be heterogeneous. Thus, a two-variance model was fit using the REPEATED statement of the MIXED procedure, grouped by pig. The mivque(0) option of the VARCOMP procedure was used to calculate the proportion of variability that each factor contributed to the total variance. Barrows (3.64%) produced chops with greater (P < 0.01) IMF content than gilts (3.20%), and barrows (2.14) had greater (P < 0.01) IMF variability than gilts (1.23). Chops from MQ pigs (4.02%) exhibited greater (P < 0.01) IMF content than LG (2.82%), and MQ (1.76) had greater IMF variability (P < 0.01) than LG pigs (0.97). Chops from locations A (3.80%) and D (3.77%) had greater IMF than B (3.34%; P < 0.01), and A, B, and D had greater IMF than C (2.77%; P < 0.01). Variances of IMF also differed (A = 1.44, B = 1.59, C = 1.05, and D = 2.18; P = 0.01) across chop locations. Of the variability in IMF, 33.0% was attributed to sire line, 10.16% to chop location, and 4.01% to sex, with 52.83% not accounted for by these three factors. Location A chops were the most (P < 0.01) tender (2.57 kg) and C chops the least (P < 0.01) tender (2.93 kg), while B and D chops were intermediate and not different from each other. No differences in variability (P = 0.40) of tenderness were observed among chop locations (A = 0.31, kg B = 0.24 kg, C = 0.24 kg, and D = 0.23 kg). These results demonstrated that variability in tenderness values did not reflect the variability of IMF. In conclusion, chop location, sex, and sire line all contribute to the amount and variability of pork loin marbling.

EFFECTIVENESS OF IMPLEMENTATION OF PROBLEM BASED LEARNING MODELS TO IMPROVE STUDENTS’ MATHEMATICAL LEARNING OUTCOMES IN XI-MIPA SMA NEGERI 8 PEKANBARU

The background of this research was the low ability of student’ mathematical learning outcomes of SMA Negeri 8 Pekanbaru. The purposes of this research were: 1) to find the significance of students’ mathematical learning outcomes who study through Problem Based Learning (PBL) model with student who study through conventional learning with scientific approach; (2) to examine the improvement of students’ mathematical learning outcomes who study through PBL model and students who study through conventional learning with scientific approach in class XI-MIPA SMA Negeri 8 Pekanbaru. This research was an experimental research (quasi experiment) with The Nonequivalent Pretest-Posttest Control Group Design. The population of this research is all students of class XI-MIPA SMA Negeri 8 Pekanbaru. Sample of this research consist of two classes, class XI-MIPA4 as experiment class and XI-MIPA3 as control class. The data of this research were student’s mathematical learning outcomes from pretest-posttest. Students’ mathematical learning outcomes were analyzed using independent sample t-test which was preceded by normality test and homogeneity of variances test. The result of this research shows that the improvement of students’ mathematical learning outcomes who study through PBL model is higher than students who study through conventional learning with scientific approach.

Comparisons of Four Methods for Thinning Eucalyptus Hybrid Coppice Shoots in Brazil

Both manual and semi-mechanized systems are used for operations involved in coppice remodeling. Thus, there is a paradigm about the higher yield of semi-mechanized operations compared to manual operations. However, the small volume of research on this subject does not present data which is capable of confirming this hypothesis. Thus, the present study aimed to perform a technical analysis of costs, quality and productivity of different methods for conducting regrowth in Eucalyptus grandis x Eucalyptus urophylla hybrid plantations under coppice regeneration in areas of forest fostering. The experiment was conducted under a completely randomized design with four treatments (sprouting methods) and four replications in plots of 360m² each. The methods used were: brushcutter, sickle, machete and hand digger. An F-test (p <0.05) was performed to verify the differentiation between treatments for a given characteristic after verifying the normal distribution of data and homogeneity of variances. The means were compared by analysis of variance at the 5% significance level to analyze if there was significant difference between the operating times in the analyzed methods. An estimate of the costs per hectare was subsequently obtained in each offspring method and the quality of the operation was evaluated by observing the frequency of damage to the remaining trunk. The mean operation time of the methods did not differ significantly (p> 0.05). The brushcutter presented the highest cost per hectare (US$ 40,06/ha-1) and the excavator presented the lowest (US$ 18,65/ha-1). Spreading with the brushcutter presented the lowest percentage of mechanical damage (6.88%) and the sickle obtained the highest (20.63%). It was concluded that the operation with brushcutter was the method that provided the highest productivity, but has the highest operational cost, making the method with brushcutter, advantageous for its low cost, associated with a satisfactory productivity.