Experiment measurement of Alford's force in axial-flow turbomachinery

Results of experimental measurements made on a small high speed, axial flow test apparatus are presented to verify the existence of Alford's force (that circumferential variation of blade-tip clearances in axial-flow turbomachinery will produce cross-coupled (normal to the eccentricity) aerodynamic forces on the rotor) and to investigate the validity of his mathematical prediction model

Prediction of pressure fluctuation in sounding rockets and manifolded recovery systems

The determination of altitude by means of barometric sensors in sounding rocket applications is discussed. A method for predicting the performance of such sensing systems is needed. A method is developed for predicting the pressure-time response of a volume subjected to subsonic air flow through from one to four passages. The pressure calculation is based on one-dimensional gas flow with friction. A computed program has been developed which solves the differential equations using a self-starting predictor-corrector integration technique. The input data required are the pressure sensing system dimensions, pressure forcing function(s) at the inlet port(s), and a trajectory over the time of analysis (altitude-velocity-time), if the forcing function is trajectory dependent. The program then computes the pressure-temperature history of the gas in the manifold over the time interval specified

Wage Differentials and Market Imperfections: Some Cross Section Results in Canadian Manufacturing Industries

Dans l'article précédent, l'auteur tente de démontrer dans quelle mesure les imperfections des marchés des produits et des facteurs de production sont responsables des différences de salaire. L'article se divise en trois parties. La première partie est consacrée à l'examen théorique des différences de salaire et des imperfections des marchés, à la formulation d'une hypothèse vérifiable et à l'ébauche d'un modèle. La deuxième partie rend compte des résultats concrets obtenus. S'y ajoute enfin une conclusion.Théoriquement, deux points apparaissent importants. En elles-mêmes, les imperfections du marché des produits ne peuvent engendrer les différences de salaire ; d'autre part, ces différences ne peuvent exister que s'il y a des imperfections sur le marché des facteurs, autrement dit, si, du côté de l'employeur, il y a monopole ou si, de l'autre, les syndicats sont très puissants.Par la théorie, on ne peut guère être éclairé sur ce qui se passe généralement lorsqu'il y a interaction du marché des produits et du marché des facteurs. Globalement, selon notre hypothèse, l'existence conjointe d'un syndicalisme fort et la situation de monopole de l'entreprise exerceraient une certaine influence sur la négociation des salaires. Pour approfondir cette hypothèse, il s'agissait de prendre pour acquis que l'objectif principal des syndicats est de faire augmenter les salaires au-dessus du niveau du marché des facteurs tout en maintenant le niveau de l'emploi. Il s'ensuit que l'action syndicale sera beaucoup plus perceptible dans les industries qui, de l'avis des dirigeants syndicaux, sont en mesure d'accepter des hausses de salaire sans réduire les occasions d'emploi pour les membres du syndicat. Ceci signifie qu'il n'y a guère de marge pour l'action syndicale dans les secteurs très concurrentiels de l'économie, étant donné que les profits des entreprises tendent alors vers le point zéro, et que, en conséquence, on ne peut y obtenir d'augmentation de salaire sans risquer de provoquer une réduction des emplois. Dans les circonstances, on ne peut s'attendre à ce que l'efficacité des syndicats y soit très grande.D'autre part, si les entreprises monopolisées fonctionnement sans être troublées par les revendications des syndicats, elles paieront les taux de salaire courants et, s'il y a profit clair, il restera intact. Par conséquent, un syndicat ne peut obtenir de hausses de salaire que dans les industries où l'on sait qu'il y a des profits clairs. Ces industries sont nécessairement celles qui détiennent une certaine exclusivité sur le marché des produits.Si ceci est exact, les hypothèses suivantes peuvent se vérifier. En premier lieu, on notera un rapport positif entre les taux de salaire et la puissance du syndicat. En deuxième lieu, il y a aussi un rapport positif entre les salaires et la concentration qui favorise la puissance de l'entreprise sur le marché. Toutefois, cette dernière prévision se fonde sur l'hypothèse déterminante d'une corrélation entre le degré de syndicalisation et le degré de concentration, ce qui voudrait dire que la concentration n'exerce aucune influence sur les salaires et que le rapport salaire-concentration est faux.En utilisant surtout les données relatives à la concentration, aux profits, au degré de syndicalisation et à la productivité, nous avons examiné leur impact sur les salaires en recourant à la technique de la régression multiple pour évaluer à la fois les coefficients des séries chronologiques et des échantillonnages. Le résultat le plus marquant qu'on a obtenu de cette analyse peut se formuler ainsi : des syndicats puissants et une situation d'oligopole sur le marché exercent une influence positive certaine sur les salaires. Cependant, on ne sait pas par là l'ampleur des différences de salaire dont on peut attribuer la responsabilité aux syndicats lorsque l'on ne décèle pas la présence d'oligopole sur le marché. On ne connaît pas plus d'ailleurs l'ampleur des différences de salaire attribuables à la présence d'un oligopole sans pression de la part des syndicats. Naturellement, il faudrait poursuivre plus avant les analyses pour faire le départ entre la différence dans les salaires et le degré de concentration du marché.The purpose of this paper is to analyse the extent to which factor and product market imperfections are responsible for wage differentials. The conclusion is that without some form of factor market imperfection, the existence of imperfection in the product market cannot explain wage differentials

ElectrochemicalN-demethylation of tropane alkaloids

A practical, efficient, and selective electrochemicalN-demethylation method of tropane alkaloids to their nortropane derivatives is described. Nortropanes, such as noratropine and norscopolamine, are important intermediates for the semi-synthesis of the medicines ipratropium or oxitropium bromide, respectively. Synthesis was performed in a simple home-made electrochemical batch cell using a porous glassy carbon electrode. The reaction proceeds at room temperature in one step in a mixture of ethanol or methanol and water. The method avoids hazardous oxidizing agents such as H(2)O(2)orm-chloroperbenzoic acid (m-CPBA), toxic solvents such as chloroform, as well as metal-based catalysts. Various key parameters were investigated in electrochemical batch or flow cells, and the optimized conditions were used in batch and flow-cells at gram scale to synthesize noratropine in high yield and purity using a convenient liquid-liquid extraction method without any need for chromatographic purification. Mechanistic studies showed that the electrochemicalN-demethylation proceeds by the formation of an iminium intermediate which is converted by water as the nucleophile. The optimized method was further applied to scopolamine, cocaine, benzatropine, homatropine and tropacocaine, showing that this is a generic way ofN-demethylating tropane alkaloids to synthesize valuable precursors for pharmaceutical products

Onecut-dependent Nkx6.2 transcription factor expression is required for proper formation and activity of spinal locomotor circuits.

In the developing spinal cord, Onecut transcription factors control the diversification of motor neurons into distinct neuronal subsets by ensuring the maintenance of Isl1 expression during differentiation. However, other genes downstream of the Onecut proteins and involved in motor neuron diversification have remained unidentified. In the present study, we generated conditional mutant embryos carrying specific inactivation of Onecut genes in the developing motor neurons, performed RNA-sequencing to identify factors downstream of Onecut proteins in this neuron population, and employed additional transgenic mouse models to assess the role of one specific Onecut-downstream target, the transcription factor Nkx6.2. Nkx6.2 expression was up-regulated in Onecut-deficient motor neurons, but strongly downregulated in Onecut-deficient V2a interneurons, indicating an opposite regulation of Nkx6.2 by Onecut factors in distinct spinal neuron populations. Nkx6.2-null embryos, neonates and adult mice exhibited alterations of locomotor pattern and spinal locomotor network activity, likely resulting from defective survival of a subset of limb-innervating motor neurons and abnormal migration of V2a interneurons. Taken together, our results indicate that Nkx6.2 regulates the development of spinal neuronal populations and the formation of the spinal locomotor circuits downstream of the Onecut transcription factors

Effect of sumac (Rhus coriaria L.) seed powder on growth, carcass traits, blood parameters, immune system and selected ileal microorganisms of broilers

Sumac (Rhus coriaria L.) is a plant species belong to Anacardiaceous family that is worldwide diffused. The sumac seed power (SSP), produced by grinding dried fruits, is recognized to have defensive and beneficial effects on numerous health‑related problems. In this study, SSP was included in broilers basal‑diet to investigate the comparative effects of different levels of SSP on performance, carcass characteristics, blood parameters, immune system and ileal microorganisms. A total of 225, one day‑old male broilers (Ross 308) were randomly assigned to the five dietary treatments with three replicates per treatment. The experimental diets were: basal‑diet (BD); and BD including 0.05, 0.10, 0.15 and 0.20% SSP, respectively. During the whole feeding period (42 days), birds fed corn‑based grower (1‑21 days) and finisher (22‑42 days) diets, respectively. Results indicated that supplementing SSP had no effect on broiler body weight gain, feed intake and feed conversion as well as carcass characteristics (P > 0.05). Similarly, blood total protein, albumin, glucose and triglyceride were not influenced by dietary SSP. Conversely, serum total cholesterol and LDL‑cholesterol levels were decreased, while HDL‑cholesterol increased in all SSP fed groups compared to control (P < 0.05). In this study the addition of SSP in broilers diets did not show any effect on blood heterophils and lymphocyte. Moreover, the lactobacillus count remained unaffected by dietary treatments, while E. coli count in broiler ileal content was lower when fed 0.10% SSP than the other groups (P < 0.05). Thus, the present findings indicated a positive effect of feeding SSP (especially at 0.10% diet) on blood cholesterol levels and E. coli count in broiler chickens

Effect of dietary simvastatin and L-carnitine supplementation on blood biochemical parameters, carcass characteristics and growth of broiler chickens

The aim of this study was to evaluate the effect of simvastatin (SIM) and L-carnitine (LC) additives and their interactions, on productive performance and carcass quality of broilers. For this purpose, a feeding trial was conducted, under 3×3 factorial design, using SIM at 0, 1 or 2 g/kg level and LC at 0, 150 or 300 mg/kg level in a basal-diet and originating a total of nine treatments: T1 (control-diet, 0/0), T2 (0/150), T3 (0/300), T4 (1/0), T5(1/150), T6 (1/300), T7 (2/0), T8 (2/150), and T9 (2/300). Feed intake was higher in T2 (4716 g), T7 (4722 g) and T9 (4698 g) than in T1 (4545 g; P<0.05) considering the last growing phase (35-42 days) or whole 42-day production cycle. An improvement of feed efficiency was also observed in T8 (1.64) and T9 (1.67) when compared to T1 (1.77; P<0.05), and these were mainly due to SIM × LC interactions (P<0.05). The LC influenced positively (P<0.05) the weight of eviscerated carcass, breast, drumsticks and abdominal fat, as well as plasma triglycerides level. This findings suggests that the combination of SIM and LC additives have a positive influence on growth performance and carcass traits of broiler chickens

Does visual cortex lactate increase following photic stimulation in migraine without aura patients? A functional 1H-MRS study

Proton magnetic resonance spectroscopy (1H-MRS) has been used in a number of studies to assess noninvasively the temporal changes of lactate (Lac) in the activated human brain. Migraine neurobiology involves lack of cortical habituation to repetitive stimuli and a mitochondrial component has been put forward. Our group has recently demonstrated a reduction in the high-energy phosphates adenosine triphosphate (ATP) and phosphocreatine (PCr) in the occipital lobe of migraine without aura (MwoA) patients, at least in a subgroup, in a phosphorus MRS (31P-MRS) study. In previous studies, basal Lac levels or photic stimulation (PS)-induced Lac levels were found to be increased in patients with migraine with aura (MwA) and migraine patients with visual symptoms and paraesthesia, paresia and/or dysphasia, respectively. The aim of this study was to perform functional 1H-MRS at 3 T in 20 MwoA patients and 20 control subjects. Repetitive visual stimulation was applied using MR-compatible goggles with 8 Hz checkerboard stimulation during 12 min. We did not observe any significant differences in signal integrals, ratios and absolute metabolite concentrations, including Lac, between MwoA patients and controls before PS. Lac also did not increase significantly during and following PS, both for MwoA patients and controls. Subtle Lac changes, smaller than the sensitivity threshold (i.e. estimated at 0.1–0.2 μmol/g at 3 T), cannot be detected by MRS. Our study does, however, argue against a significant switch to non-aerobic glucose metabolism during long-lasting PS of the visual cortex in MwoA patients