Influence of water pressure on the final quality of arabica espresso coffee. Application of multivariate analysis

Water pressure is one of the most important factors which influence the final quality of espresso coffee (EC). However, few studies dealing with this issue have been found. The aim of this work was to study the effect of water pressure on the final quality of Arabica ECs as well as to classify ECs prepared at different pressures (7, 9, and 11 atm) according to their physicochemical and sensory characteristics, key odorants, by means of multivariate analysis. Statistically, principal component 1 (PC1) separated ECs prepared at 7 and 9 atm from ECs prepared at 11 atm and included the main foam and taste characteristics as well as some key odorants and flavor compounds. ECs prepared at 7 and 9 atm were separated by principal component 2 (PC2). Coffees prepared at 9 atm showed consistency of foam and a high percentage of key odorants related to freshness and fruity, malty, and buttery flavors. A simple discriminate function was obtained by discriminate analysis, allowing the classification of ECs prepared at three pressures into their respective groups with a success rate of 100%.     

水稻萌发耐淹性种质资源筛选及QTL定位

作者用水培的方法研究水稻不同生育期缺磷的影响,结果证明：幼苗期缺磷的影响最显著,表现出生长缓慢,分蘖减少。因此,栽培水稻在幼苗期及分蘖期充分供应磷肥有特别重要意义。     

Optimizing headspace temperature and time sampling for identification of volatile compounds in ground roasted Arabica coffee

Equilibration time and temperature were the factors studied to choose the best conditions for analyzing volatiles in roasted ground Arabica coffee by a static headspace sampling extraction method. Three temperatures of equilibration were studied: 60, 80, and 90 degrees C. A larger quantity of volatile compounds was extracted at 90 degrees C than at 80 or 60 degrees C, although the same qualitative profile was found for each. The extraction of the volatile compounds was studied at seven different equilibration times: 30, 45, 60, 80, 100, 120, and 150 min. The best time of equilibration for headspace analysis of roasted ground Arabica coffee should be selected depending on the chemical class or compound studied. One hundred and twenty-two volatile compounds were identified, including 26 furans, 20 ketones, 20 pyrazines, 9 alcohols, 9 aldehydes, 8 esters, 6 pyrroles, 6 thiophenes, 4 sulfur compounds, 3 benzenic compounds, 2 phenolic compounds, 2 pyridines, 2 thiazoles, 1 oxazole, 1 lactone, 1 alkane, 1 alkene, and 1 acid.     

Genotypic versus phenotypic identification of staphylococcal species of canine origin with special reference to Staphylococcus schleiferi subsp. coagulans

A comparative study was performed to examine the respective accuracy of 16S rDNA sequencing and of the commercial biochemical assay ID32 STAPH (bioMérieux, Marcy l'Etoile, France) in the identification of 232 staphylococcal samples representing 20 species and subspecies isolated from 367 dogs. Notable differences in species distribution were observed by comparing genotypic and phenotypic data. Partial sequencing of 16S rDNA resulted in an unambiguous identification of 226 (97.4%) of the isolates, whereas the phenotypic approach resulted in a correct diagnosis of 162 (69.8%) of the isolates. Statistical agreement between genotypic and phenotypic identification of staphylococci was substantial (Kappa coefficient of 0.6-0.8) for Staphylococcus aureus, S. hominis, S. warneri, S. cohnii subsp. urealyticus, and S. simulans, and "almost perfect" (Kappa coefficient of 0.8-1) for S. intermedius, S. epidermidis, S. equorum, S. haemolyticus, S. sciuri, and S. kloosi. No agreement above that expected by chance (Kappa coefficient=0) was observed for S. schleiferi subsp. coagulans, which was either confounded with S. intermedius and S. capitis, or categorized as unacceptable by the biochemical assay. Given the growing importance of this pathogen in veterinary medicine and its frequent misidentification with related staphylococci, a PCR-RFLP approach producing a S. schleiferi-specific restriction profile was developed. This fast and reliable assay represents a valuable tool in assisting in the monitoring of this pathogen.     

Genotypic characterization and phylogenetic analysis of Cryptosporidium sp. from domestic animals in Brazil

The purpose of the present study was the genetic characterization, sequencing and phylogenetic analysis of 18S rDNA sequences of Cryptosporidium isolates obtained from different animal hosts in Brazil. Fecal samples containing Cryptosporidium oocysts were obtained from chickens, ducks, quails, guinea pigs, dairy calves, dogs and cats. For amplification of 18S rDNA sequences the Secondary-PCR product of the extracted DNA from fecal suspension of each studied animal was utilized. The primary genetic characterization of Cryptosporidium sp. was performed using RFLP with the enzymes SspI and VspI. DNA samples were sequenced and subjected to phylogenetic analysis. The results showed C. baileyi infecting two ducks and one quail and C. melagridis infecting one chicken. The sequences obtained from Cryptosporidium sp. infecting guinea pigs were not identified within groups of known Cryptosporidium species. The isolates found parasitizing cats and one dog were diagnosed as C. felis and C. canis, respectively. One isolate of calf origin was identified as C. parvum. The phylogenetic analysis showed clear distribution of isolates between two Cryptosporidium sp. groups according to their gastric or intestinal parasitism. A great genetic distance was observed between C. felis and C. canis from Brazil when compared to the reference sequences obtained from GenBank. The results obtained during this study constitute the first report of rDNA sequences from C. baileyi, C. meleagridis, C. felis, C. canis and C. parvum isolated in Brazil.     

Ordinary Least Squares Regression of Ordered Categorical Data: Inferential Implications for Practice

Ordered categorical variables are frequently encountered as response variables in many disciplines. Agricultural examples include quality assessments of soil or food products, and evaluation of lesion severity, such as teat ends status in dairy cattle. Ordered categorical responses (OCR) are characterized by multiple levels recorded on a ranked scale, whereby levels appraise order but may not be informative of relative magnitude or proportionality between levels. A number of statistically sound methods are available in the standard toolbox to deal with OCR, such as constrained cumulative logit and probit models; however, these are commonly underutilized in practice. Instead, ordinary least squares linear regression (OLSLR) is often employed to infer upon OCR, despite violation of basic model assumptions. In this study, we investigate the inferential implications of OLSLR-based inference on OCR using simulated data to explore realized Type I error rate and realized statistical power under a variety of scenarios. The design of the simulation study was motivated by a data application, thus considering increasing number of levels and various frequency distributions of the OCR. We then illustrate inferential performance of OLSLR relative to a probit regression model fitted to an OCR using a survey dataset of veterinarian antimicrobial use in cattle feedlots. This article has supplementary material online.     

Formation and decay of ethylenethiourea (ETU) in soil and water under tropical conditions

Mancozeb is a fungicide frequently used in tropical countries. It rapidly decomposes into ethylenethiourea (ETU), a more stable and toxic metabolite than mancozeb that is, therefore, regarded as a pollutant of concern. The objective was to study ETU formation and decay kinetics in soil and water under tropical conditions in order to assess its potential for accumulation. Batch experiments, spiked with either mancozeb or ETU, were carried out under natural (= active) as well as tyndallized conditions. In active soils, dissipation of ETU occurred significantly faster (half‐life 1.5 h) than in tyndallized soils (half‐life time 28 h). In water under natural and sterile conditions, decay was slower than in soils with an ETU half‐life time of 115 and 99 h, respectively. Microbial activity was seen to play an important role in ETU dissipation in soil. However, in water nonbiological processes seem to be more important in the breakdown of the molecule, with hydrolysis being the most probable decay mechanism. Decay of both mancozeb and ETU was found to occur more rapidly than previously reported. The high humidity and temperatures under the simulated humid tropical conditions, and higher microbial activity, lead to more rapid decay of these molecules than under other conditions. Nevertheless, a concentration of 1.29 mg ETU L^–1 was still observed 8 d after adding mancozeb (20.83 mg L^–1) to water under humid tropical conditions. These results suggest that, in comparable regions in the humid tropics, it is unlikely that ETU would accumulate in soil but it represents a potential risk for accumulation in water bodies.