36 research outputs found
Thermodynamic instabilities in dynamical quark models with complex conjugate mass poles
We show that the CJT thermodynamic potential of dynamical quark models with a
quark propagator represented by complex conjugate mass poles inevitably
exhibits thermodynamic instabilities. We find that the minimal coupling of the
quark sector to a Polyakov loop potential can strongly suppress but not
completely remove such instabilities. This general effect is explicitly
demonstrated in the framework of a covariant, chirally symmetric, effective
quark model.Comment: Minor typos corrected, submitted versio
Relationship between internal accuracy and load-bearing capacity of minimally invasive lithium disilicate occlusal veneers
Purpose: To test whether internal accuracy affects the load-bearing capacity of 0.5-mm-thick occlusal veneers made out of milled or heat-pressed lithium disilicate (LS2).
Materials and methods: Extracted human molars (N = 80) were divided into four groups (n = 20 each) depending on the bonding substrate (enamel [E] or dentin [D]) and the fabrication method (milling [CAD] or heat pressing [PRE]) for the occlusal LS2 veneers: (1) E-CAD, (2) D-CAD, (3) E-PRE, or (4) D-PRE. After restoration fabrication, the abutment teeth and the corresponding restorations were scanned and superimposed in order to measure the marginal and internal accuracy. After adhesive cementation, the specimens were thermomechanically aged and thereafter loaded until fracture. The load-bearing capacities (Fmax) were measured. Fmax and the marginal and internal accuracy between the groups were compared using Kruskal-Wallis test (P < .05) and pairwise group comparisons. In addition, the relationship between Fmax and the internal accuracy was analyzed using Spearman rank correlation.
Results: Median Fmax values (and first and third quartiles) per group were as follows: 1,495 N (Q1: 932; Q3: 2'318) for E-CAD; 1,575 N (Q1: 1,314; Q3: 1,668) for E-PRE; 1,856 N (Q1: 1,555; Q3: 2,013) for D-CAD; and 1,877 N (Q1: 1,566; Q3: 2,131) for D-PRE. No statistical difference was found between the groups (P = .0981). Overall, the internal accuracy in the areas of the cusp (P < .0007) and fossa (P < .0001) showed significant differences. While no significant differences were detected in the marginal area (P = .3518), a significant correlation with a negative linear relationship was found between the 3D internal accuracy and the Fmax values (P = .0007).
Conclusion: An increase in the internal accuracy raised the load-bearing capacity of minimally invasive LS2 occlusal veneers. In general, the restorations bonded to dentin in the occlusal regions showed a better accuracy compared to those bonded to enamel
HYGIENE, WELFARE AND BEHAVIOUR OF LAYING HENS HOUSED IN CONVENTIONAL CAGES AND ALTERNATIVE SYSTEMS
U radu je prikazano istraživanje dva sustava smještaja nesilica za proizvodnju konzumnih jaja, klasični i alternativni (aviarij) s posebnim osvrtom na higijenu zraka, dobrobit i ponašanje neslica. Higijenska kakvoća zraka u alternativnim sustavima držanja značajno je lošija u odnosu na konvencionalne sustave glede sadržaja bakterija, gljivica, prašine i endotoksina. Što se tiče dobrobiti i zadovoljenja bihevioralnih potreba alternativni sustavi odnosno aviariji su prihvatljiviji, međutim ovi sustavi s higijenskog stajališta ne zadovoljavaju s obzirom na veći broj zaprljanih i polomljenih jaja, kao i povećanu mogućnost izbijanja bolesti.This paper demonstrate two housing systems for production consume eggs, clasical and alternative (aviary) with special overview on air hygiene, welfare and laying hens behaviour. Hygienic air quality in alternative housing systems is significantly worse in relations with conventional systems regarding content of bacteria, fungi, dust and endotoxins. Considering welfare and satisfaction of behavioral needs alternative systems are acceptable, however this systems from hygienic point of view do not satisfy considering more dirty and broken eggs as well as great possibility of diseases emerge
DJELOVANJE TEMPERATURE ZRAKA, RELATIVNE VLAGE I BRZINE STRUJANJA ZRAKA NA BROJ GLJIVICA I ZRAKOM NOŠENU EMISIJU IZ MLIJEČNIH STAJA NA OKOLIŠ
An Merck MAS-100 air sampler was employed with respective nutrient agar for capture, incubation and counting of airborne fungi. Microclimate parameters were simultaneously determined by a Testo 400 device. Air sampling was done once a week in the morning, at noon at 12:00) and in the evening (at 19:00) during two autumn months. Within the barn, measurements were performed in the animal housing area along the feedlot, and outside the barn at a distance of 5 m, 25 m and 50 m eastward and westward from the barn. The mean values of total airborne fungi count in the barn air was 7.23x103 CFU/m3 in the morning, 2.84x104 CFU/m3 at noon, and 7.25x104 CFU/m3 in the evening. Fungi count showed a statistically significant decrease as close as 5 m from the barn (p0.05). Rezultati istraživanja pokazuju da uvjeti držanja, konstrukcija i položaj staje, te broj mliječnih krava ne utječu na broj gljivica i emisiju u staji i izvan nje, te tako ne djeluju na zdravlje i proizvodnju životinja ili onečišćenje okoliša
Prevalence of contagious and environmental mastitis-causing bacteria in bulk tank milk and its relationships with milking practices of dairy cattle herds in São Miguel Island (Azores)
This study aimed to assess the degree of contamination of bulk tank milk (BTM) by Staphylococcus spp. and coliform bacteria and to identify major milking practices that help perpetuate them in dairy cattle herds in São Miguel Island. In July 2014, BTM was sampled and a survey concerning local milking practices was conducted on 100 herds. Semi quantitative multiplex polymerase chain reaction detected coagulase-negative staphylococci, Escherichia coli, Staphylococcus aureus, and other coliform bacteria (Klebsiella oxytoca, Klebsiella pneumoniae, andSerratia marcescens) in 100, 75, 59, and 35 % of BTM, respectively. According to multivariable univariate models, on herds not using hot water for cleaning the milking machine and teat liners, there was at least 3.4 more odds (P<0.01) to have S. aureus or coliform bacteria contamination in BTM. The likelihoodoffinding S.aureus inBTMwas higher(P<0.001)on herds without high hygiene during milking, when milking mastitic cows at the end, on abrupt cessation of milking at dry-off, and official milk control implementation. The glove use also favored (odds ratio (OR) 5.8; P<0.01)thedetection ofcoliformbacteriainBTM.Poormilkingpracticesidentified in this study should be avoided in order to decrease S. aureus and coliform bacteria contamination of BTM. Other factors
associated with milk quality in São Miguel Island also should be further investigated