Airplane Balance

The authors argue that the center of gravity has a preponderating influence on the longitudinal stability of an airplane in flight, but that manufacturers, although aware of this influence, are still content to apply empirical rules to the balancing of their airplanes instead of conducting wind tunnel tests. The author examines the following points: 1) longitudinal stability, in flight, of a glider with coinciding centers; 2) the influence exercised on the stability of flight by the position of the axis of thrust with respect to the center of gravity and the whole of the glider; 3) the stability on the ground before taking off, and the influence of the position of the landing gear. 4) the influence of the elements of the glider on the balance, the possibility of sometimes correcting defective balance, and the valuable information given on this point by wind tunnel tests; 5) and a brief examination of the equilibrium of power in horizontal flight, where the conditions of stability peculiar to this kind of flight are added to previously existing conditions of the stability of the glider, and interfere in fixing the safety limits of certain evolutions

Audit fees and cost of debt: differences in the credibility of voluntary and mandatory audits

Despite the extensive research on audit fees, few studies have examined the effect of audit fees on the cost of debt. Based on the credence goods theory, we examine whether the effect of audits on the cost of debt is affected by the type of audit (voluntary or mandatory) and the audit fees, as well as whether there is a combined effect of voluntary audits and audit fees, so that the effect of voluntary audits on the cost of debt is affected by audit fees. Using a sample of Spanish SMEs, we find an asymmetric effect of audit fees on the cost of debt: higher audit fees are associated with a lower cost of debt for voluntarily audited companies, while the association is not significant for mandatory audits. Results suggest that, although the type of audit and the audit fees do not have a direct effect on the credibility of audits, the combination of both factors has relevance for lenders, so that higher audit fees in the voluntary setting are positively valued by them. The study contributes to the literature on auditing by showing that voluntary audits are relevant for capital providers as long as audits are perceived of quality

Réflexions sur le sort des forêts tropicales

International audienc

Mass treatment of trachoma with azithromycin 1.5% eye drops in the Republic of Cameroon: feasibility, tolerance and effectiveness

International audienceAn epidemiological study carried out in 2006 indicated the existence of a high prevalence of blinding trachoma in the Kolofata Health District, Far North Region, Cameroon. As a result, the national blindness control program of Cameroon instituted a trachoma elimination programme using the SAFE strategy