Comparaison des qualités sensorielles de la viande et de la carcasse d’agneaux élevés au pâturage en production biologique ou conventionnelle à deux niveaux de disponibilités en herbe

Nous avons comparé les qualités sensorielles des carcasses et des viandes d’agneaux engraissés au pâturage en élevage biologique ou conventionnel (O vs. C) à deux niveaux de disponibilités en herbe (Haut H vs. Bas L). Le profil de croissance a été maintenu similaire entre les deux systèmes de production. L’expérimentation a été conduite pendant deux années avec 12 agneaux mâles castrés de race Limousine dans chaque groupe OH, OL, CH et CL chaque année. Les traitements O et C différaient par le niveau de fertilisation azotée minérale épandu sur les parcelles. Les parcelles expérimentales étaient des repousses après fauche et elles étaient conduites en pâturage tournant pour conduire à un âge moyen des agneaux à l’abattage de 5 et 6 mois dans les lots H et L respectivement. Les côtelettes O ont été moins appréciées que les côtelettes C. L’indice de rouge du muscle longissimus thoracis et lumborum après 2h d’exposition à l’air a été plus élevé chez les agneaux L que chez les agneaux H, indiquant les effets possibles d’une intensification de l’élevage biologique à travers une augmentation du chargement

Travail des enfants, enfants des rues et approche par les capabilités : Liens méthodologiques et implications pour les politiques

Le débat sur le travail des enfants a pris une ampleur considérable ces vingt dernières années. Les politiques se sont majoritairement orientées vers la promotion de l’éducation. Pourtant, le débat n’a guère fait de place à la question des enfants des rues. Intégrer cette catégorie d’enfants au débat pose de nouvelles questions. En particulier, l’éducation doit prendre une forme non violente et des espaces de travail doivent être ouverts pour les enfants des rues.The debate on child labour has taken a fullness these last twenty years. Policies are actually largely based on the promotion of education. Meanwhile, the debate has not taken into account the very question of street children. Integrating this category of children set new issues. Particularly, education must be non violent and spaces of work must be openned for street children

A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction

The XA region of the Cygnus Loop is a complex zone of radiative and nonradiative shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra and a high-resolution longslit Halpha spectrum to study the spatial emission line variations across the region. These spectral data are placed in context using ground-based, optical emission line images of the region and a far-UV image obtained by the Ultraviolet Imaging Telescope (UIT). The presence of high-ionization ions (OVI, NV, CIV) indicates a shock velocity near 170 km/s while other diagnostics indicate v_shock=140 km/s. It is likely that a large range of shock velocities may exist at a spatial scale smaller than we are able to resolve. By comparing CIV 1550, CIII 977 and CIII] 1909, we explore resonance scattering across the region. We find that a significant column depth is present at all positions, including those not near bright optical/UV filaments. Analysis of the OVI doublet ratio suggests an average optical depth of about unity in that ion while flux measurements of [SiVIII] 1443 suggest a hot component in the region at just below 10^6K. Given the brightness of the OVI emission and the age of the interaction, we rule out the mixing layer interpretation of the UV emission. Furthermore, we formulate a picture of the XA region as the encounter of the blast wave with a finger of dense gas protruding inward from the pre-SN cavity.Comment: 21 pages, 9 figures, accepted by the Astronomical Journal, July 2001 Full resolution figures available at http://fuse.pha.jhu.edu/~danforth/xa

Electronic structure and magnetic properties of pyroxenes (Li,Na)TM(Si,Ge)2O6: novel low-dimensional magnets with 90 bonds

The results of the LSDA+U calculations for pyroxenes with diverse magnetic properties (Li,Na)TM(Si,Ge)$_2$O$_6$, where TM is the transition metal ion (Ti,V,Cr,Mn,Fe), are presented. We show that the anisotropic orbital ordering results in the spin-gap formation in NaTiSi$_2$O$_6$. The detailed analysis of different contributions to the intrachain exchange interactions for pyroxenes is performed both analytically using perturbation theory and basing on the results of the band structure calculations. The antiferromagnetic $t_{2g}-t_{2g}$ exchange is found to decrease gradually in going from Ti to Fe. It turns out to be nearly compensated by ferromagnetic interaction between half-filled $t_{2g}$ and empty $e_g$ orbitals in Cr-based pyroxenes. The fine-tuning of the interaction parameters by the crystal structure results in the ferromagnetism for NaCrGe$_2$O$_6$. Further increase of the total number of electrons and occupation of $e_g$ sub-shell makes the $t_{2g}-e_g$ contribution and total exchange interaction antiferromagnetic for Mn- and Fe-based pyroxenes. Strong oxygen polarization was found in Fe-based pyroxenes. It is shown that this effect leads to a considerable reduction of antiferromagnetic intrachain exchange. The obtained results may serve as a basis for the analysis of diverse magnetic properties of pyroxenes, including those with recently discovered multiferroic behavior.Comment: 11 pages, 10 figure

Un mode de conduite biologique et un niveau élevé d'herbe améliorent la qualité nutritionelle des acides gras de la viande chez l'agneau engraisse au pâturage

This study aimed at comparing the nutritional quality of meat fatty acids (FA) of pasture-fed lambs reared organically or conventionally and offered two levels of herbage availability. Forty eight castrated male lambs of Limousine breed were used in a 2 x 2 experimental design, i.e. production system (Organic –O- vs. Conventional –C-) x level of herbage availability (High vs. Low). The O and C pastures differed in the level of on-pasture mineral N fertilization (0 vs. 100 U. ha-1. year-1) since 10 years. The level of pasture availability was managed to obtain a mean lamb age at slaughter of 5 vs. 6 months in the High and the Low level respectively. GLC analysis of fatty acids from the Longissimus thoracis muscle showed that organic farming system improved the health value of lamb meat by decreasing the level of saturated FA and especially 16:0, thus leading to a higher value of polyunsaturated FA (PUFA) to saturated FA ratio (+15%, P<0.03) and increasing the level of CLA (+18.2%, P< 0.002). The high level of herbage availability led to a better nutritional and health value of meat FA by increasing significantly deposition of n-6 PUFA (+16.3%), n-3 PUFA (+15%) and CLA (+20.2%) in LT muscle to the detriment of saturated FA (-3.4%). In conclusion, the present study confirmed the general interest of pasture-feeding on the nutritional quality of the lamb meat. It showed, for the first time, the beneficial impact of organic farming on the health value of lamb meat FA by favouring deposition of PUFA (compared to saturated FA) and CLA, this effect being reinforced by a high level of pasture availability

Роль сечової кислоти в механізмах кардіоінотропних ефектів бальнеотерапевтичного комплексу курорту Трускавець

В русле концепции оо эндогенной мочевой кислоте как одном из звеньев механизма действия биоактивной воды Нафтуся на функциональные системы организма проанализированы совместные изменения под влиянием бальнеотерапии на курорте Трускавець уровня урикемии и сократительной активности миокарда. Выявлены три типа детерминации урикемией инотропии: ураторто-, уратинверс- и уратнезависимый типы, реализация которых обуславливается констелляцией 22 исходных параметров вегетативной регуляции, велоэргометрии, электролитного и липидного обменов, гемодинамики, а также антропометрии.It is detected three types determination of inotropy by plasma level of uric acid: uratorthodependent, uratinversdependent and uratindependent types. It is selected constellation of initial parameters of vegetative regulation, veloergometry, haemodynamic, antropometry, electrolythic and lipid exchange conditionizes these types

Qualités de la viande d’agneaux d’herbe produits en élevage biologique ou conventionnel

La mention "Agriculture Biologique" sur un produit garantit une manière de produire, mais l’obligation de résultats est limitée à la conformation et l’état d’engraissement de la carcasse, d’où des questions sur les qualités alimentaires du produit viande

Comparison of the meat and carcass quality of lambs raised in organic or conventional production systems.

The ‘organic’ label on a product guarantees that synthetic fertilisers, pesticides and hormones are not used in the production process and that the use of pharmaceutical products and drugs is limited. However, product quality is often questioned and we have to anticipate the consumer demand for product quality guarantees. This study was conducted to compare the sensory and nutritional meat and carcass qualities of lambs raised under an organic (O) or a conventional (C) production system. Comparisons were made with both pasture-fed lambs and lambs that were stall-fed indoors with concentrate and hay. The experiment was conducted over two years for stall-fed lambs (S) (group O, n=24; group C, n=24) and three years for pasture-fed lambs (P) (group O, n=36; group C, n=36). For P lambs, O and C production systems differed in terms of the level of mineral N fertilisation of the pasture. For S lambs, the feed was organic vs. conventional, and the ingredients of O and C concentrates were the same. The nutritional quality of the meat (longissimus dorsi) was assessed in terms of its fatty acid (FA) composition, and the sensory quality of the loin chop was assessed by a trained sensory panel. In stall-fed lambs, the health value of meat FA for human consumption was higher in the O group than in the C group, but there was no difference in the sensory quality of the meat and the carcass between the O and C groups. In pasture-fed lambs, there were no significant differences between the O and C groups in terms of the health value of meat FA. However, in pasture-fed lambs, the loin chops had a higher level of abnormal odour of the fat in the organic than in the conventional group, probably due to a higher proportion of white clover in the diet

In which shell-type SNRs should we look for gamma-rays and neutrinos from p-p collisions?

We present a simple analytic model for the various contributions to the non-thermal emission from shell type SNRs, and show that this model's results reproduce well the results of previous detailed calculations. We show that the \geq 1 TeV gamma ray emission from the shell type SNRs RX J1713.7-3946 and RX J0852.0-4622 is dominated by inverse-Compton scattering of CMB photons (and possibly infra-red ambient photons) by accelerated electrons. Pion decay (due to proton-proton collisions) is shown to account for only a small fraction, \lesssim10^-2, of the observed flux, as assuming a larger fractional contribution would imply nonthermal radio and X-ray synchrotron emission and thermal X-ray Bremsstrahlung emission that far exceed the observed radio and X-ray fluxes. Models where pion decay dominates the \geq 1 TeV flux avoid the implied excessive synchrotron emission (but not the implied excessive thermal X-ray Bremsstrahlung emission) by assuming an extremely low efficiency of electron acceleration, K_ep \lesssim 10^-4 (K_ep is the ratio of the number of accelerated electrons and the number of accelerated protons at a given energy). We argue that observations of SNRs in nearby galaxies imply a lower limit of K_ep \gtrsim 10^-3, and thus rule out K_ep values \lesssim 10^-4 (assuming that SNRs share a common typical value of K_ep). It is suggested that SNRs with strong thermal X-ray emission, rather than strong non-thermal X-ray emission, are more suitable candidates for searches of gamma rays and neutrinos resulting from proton-proton collisions. In particular, it is shown that the neutrino flux from the SNRs above is probably too low to be detected by current and planned neutrino observatories (Abridged).Comment: 13 pages, 1 figure, accepted for publication in JCAP, minor revision

Distribution and Kinematics of O VI in the Galactic Halo

FUSE spectra of 100 extragalactic objects are analyzed to obtain measures of O VI absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the approximate velocity range from -100 to 100 km/s reveals a widespread but highly irregular distribution of thick disk O VI, implying the existence of substantial amounts of hot gas with T ~ 3x10^5 K in the Milky Way halo. Large irregularities in the distribution of the absorbing gas are found to be similar over angular scales extending from less than one to 180 degrees, indicating a considerable amount of small and large scale structure in the gas. The overall distribution of Galactic O VI is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with a scale height of 2.3 kpc, and a 0.25 dex excess of O VI in the northern Galactic polar region. The O VI absorption has a Doppler parameter b = 30 to 99 km/s, with an average value of 60 km/s . Thermal broadening alone cannot explain the large observed profile widths. The average O VI absorption velocities toward high latitude objects range from -46 to 82 km/s, with a sample average of 0 km/s and a standard deviation of 21 km/s. O VI associated with the thick disk moves both toward and away from the plane with roughly equal frequency. A combination of models involving the radiative cooling of hot fountain gas, the cooling of supernova bubbles in the halo, and the turbulent mixing of warm and hot halo gases is required to explain the presence of O VI and other highly ionized atoms found in the halo. (abbreviated)Comment: 70 pages, single-spaced, PDF format. Bound copies of this manuscript and two accompanying articles are available upon request. Submitted to ApJ