Thermal fluctuations and NMR spectra of incommensurate systems

Journal ArticleIn the presence of thermal fluctuations the incommensurate NMR line shape is a convolution of a static inhomogeneous with a dynamic homogeneous line shape which can be determined separately by 2D NMR. The form of the dynamic line shape and its variation over the inhomogeneous NMR spectrum permit a separate determination of the relative sizes of the phason and amplitudon fluctuations, compared to the static part of the order parameter. 8 7Rb 2D spectra of ultrapure Rb2ZnCU agree with the above theory and show the existence of a temperature range where the incommensurate splitting induced by the static part of the order parameter is averaged out by thermal fluctuations

The order parameter-entropy relation in some universal classes: experimental evidence

The asymptotic behaviour near phase transitions can be suitably characterized by the scaling of $\Delta s/Q^2$ with $\epsilon=1-T/T_c$, where $\Delta s$ is the excess entropy and $Q$ is the order parameter. As $\Delta s$ is obtained by integration of the experimental excess specific heat of the transition $\Delta c$, it displays little experimental noise so that the curve $\log(\Delta s/Q^2)$ versus $\log\epsilon$ is better constrained than, say, $\log\Delta c$ versus $\log\epsilon$. The behaviour of $\Delta s/Q^2$ for different universality classes is presented and compared. In all cases, it clearly deviates from being a constant. The determination of this function can then be an effective method to distinguish asymptotic critical behaviour. For comparison, experimental data for three very different systems, Rb2CoF4, Rb2ZnCl4 and SrTiO3, are analysed under this approach. In SrTiO3, the function $\Delta s/Q^2$ does not deviate within experimental resolution from a straight line so that, although Q can be fitted with a non mean-field exponent, the data can be explained by a classical Landau mean-field behaviour. In contrast, the behaviour of $\Delta s/Q^2$ for the antiferromagnetic transition in Rb2CoF4 and the normal-incommensurate phase transition in Rb2ZCl4 is fully consistent with the asymptotic critical behaviour of the universality class corresponding to each case. This analysis supports, therefore, the claim that incommensurate phase transitions in general, and the A$_2$BX$_4$ compounds in particular, in contrast with most structural phase transitions, have critical regions large enough to be observable.Comment: 13 pp. 9 ff. 2 tab. RevTeX. Submitted to J. Phys.: Cond. Matte

Optimization of wear loss in silicon nitride (Si3N4)–hexagonal boron nitride (hBN) composite using DoE–Taguchi method

Introduction The contacting surfaces subjected to progressive loss of material known as ‘wear,’ which is unavoidable between contacting surfaces. Similar kind of phenomenon observed in the human body in various joints where sliding/rolling contact takes place in contacting parts, leading to loss of material. This is a serious issue related to replaced joint or artificial joint. Case description Out of the various material combinations proposed for artificial joint or joint replacement Si3N4 against Al2O3 is one of in ceramic on ceramic category. Minimizing the wear loss of Si3N4 is a prime requirement to avoid aseptic loosening of artificial joint and extending life of joint. Discussion and evaluation In this paper, an attempt has been made to investigate the wear loss behavior of Si3N4–hBN composite and evaluate the effect of hBN addition in Si3N4 to minimize the wear loss. DoE–Taguchi technique is used to plan and analyze experiments. Conclusion Analysis of experimental results proposes 15 N load and 8 % of hBN addition in Si3N4 is optimum to minimize wear loss against alumina

Wild boar density data generated by camera trapping in nineteen European areas

This report presents the results of field activities in relation to the generation of reliable wild boar density values by camera trapping (CT) in 19 areas in Europe, mainly in East Europe. Random Encounter Model (REM) densities ranged from 0.35±0.24 to 15.25±2.41 (SE) individuals/km2. No statistical differences in density among bioregions were found. The number of contacts was the component of the trapping rate that determined the coefficient of variation (CV) the most. The daily range (DR) significantly varied as a function of management; the higher values were detected in hunting grounds compared to protected areas, indicating that movement parameters are population specific, and confirming the potential role of hunting activities in increasing wild boar movement and contact rates among individual or groups. The results presented in this report illustrate that a harmonized approach to actual wildlife density estimation (namely for terrestrial mammals) is possible at a European scale, sharing the same protocols, collaboratively designing the study, processing, and analysing the data. This report adds reliable wild boar density values that have the potential to be used for wild boar abundance spatial modelling, both directly or to calibrate outputs of model based on abundance (such as hunting bags) or occurrence data. Future REM developments should focus on improving the precision of estimates (probably through increased survey effort). Next steps require an exhaustive and representative design of a monitoring network to estimate reliable trends of wild boar populations as a function of different factors in Europe. In this regard, the newly created European Observatory of Wildlife will be a network of observation points provided by collaborators from all European countries capable to monitor wildlife population at European level.EFSA-Q-2020-00677Peer reviewe

The efficacy of flubendazole against Trichinella spiralis in swine

A trial was undertaken to assess the efficacy of flubendazole against experimentally induced trichinellosis in pigs when given mixed with food at different dose rates. At the start of the experiment, 48 pigs were infected with approximately 35,000 larvae of Trichinella spiralis, afterwhat the animals were distributed in six groups. The first three groups were used to test the activity of the drug against adult stages. Other three groups served to define the efficacy against muscle larvae. The dose rate of flubendazole varied according to the purpose of the experiment (from 8 mg/kg up to 62 mg/kg). At the end of the trial, the pigs were necropsied and the number of adults and larvae in predilection muscles were determined. At a dose rate of 8 mg/kg flubendazole supplied with food during eight days was 100 % effective against adults. At a dose rate of 31 mg/kg flubendazole administered for 14 days was 72.35 % effective. Treatment with higher dosages of flubendazole (62 mg/kg) resulted in increased efficacy (87.77 %) against the parasites. The biological assay performed with larvae from the muscle samples originating from the pigs treated with 62 mg/kg showed that at least half of the larvae were not infective

The efficacy of flubendazole against

A trial was undertaken to assess the efficacy of flubendazole against experimentally induced trichinellosis in pigs when given mixed with food at different dose rates. At the start of the experiment, 48 pigs were infected with approximately 35,000 larvae of Trichinella spiralis, afterwhat the animals were distributed in six groups. The first three groups were used to test the activity of the drug against adult stages. Other three groups served to define the efficacy against muscle larvae. The dose rate of flubendazole varied according to the purpose of the experiment (from 8 mg/kg up to 62 mg/kg). At the end of the trial, the pigs were necropsied and the number of adults and larvae in predilection muscles were determined. At a dose rate of 8 mg/kg flubendazole supplied with food during eight days was 100 % effective against adults. At a dose rate of 31 mg/kg flubendazole administered for 14 days was 72.35 % effective. Treatment with higher dosages of flubendazole (62 mg/kg) resulted in increased efficacy (87.77 %) against the parasites. The biological assay performed with larvae from the muscle samples originating from the pigs treated with 62 mg/kg showed that at least half of the larvae were not infective

Le transplant libre j\ue9junal r\ue9vascularis\ue9 pour la reconstruction du pharynx etde l'oesophage cervical

Reconstruction of the pharynx and cervical esophagus by means of jejunal free flap. Reconstruction of the pharynx and cervical part of the esophagus after total laryngopharyngectomy can be done by different surgical techniques. The use of a revascularized jejumal free flap has currently appears to be a methodof choice. The authors report on 22 patients treated by surgery in the years 1990-1997. All the patients were males, aged 38-67 years. In all cases total laryngopharyngectomies, and in some also resection of the upper part of the esophagus were performed owing to {carcinoma.Seventeen} patients had carcinoma situated in hypopharynx, 3 in the larynx, and two in the {oropharynx.The} esophagus was not involved in 15 patients, while in 7 patients the tumor was found to have spread from the pharynx into the esophageal orifice. By the end of 1997, out af all surgically treated patients 8 were free of recurrence, 10 had died due to progressing disease and one due to surgery-related complications; one patient of cancer-underlated disease, and two patients have the disease in progress