The forgotten monoid

We study properties of the forgotten monoid which appeared in work of Lascoux and Schutzenberger and recently resurfaced in the construction of dual equivalence graphs by Assaf. In particular, we provide an explicit characterization of the forgotten classes in terms of inversion numbers and show that there are n^2-3n+4 forgotten classes in the symmetric group S_n. Each forgotten class contains a canonical element that can be characterized by pattern avoidance. We also show that the sum of Gessel's quasi-symmetric functions over a forgotten class is a 0-1 sum of ribbon-Schur functions.Comment: 13 pages; in version 3 the proof of Proposition 3 is correcte

Well-posedness of the Stokes-Coriolis system in the half-space over a rough surface

This paper is devoted to the well-posedness of the stationary $3$d Stokes-Coriolis system set in a half-space with rough bottom and Dirichlet data which does not decrease at space infinity. Our system is a linearized version of the Ekman boundary layer system. We look for a solution of infinite energy in a space of Sobolev regularity. Following an idea of G\'erard-Varet and Masmoudi, the general strategy is to reduce the problem to a bumpy channel bounded in the vertical direction thanks a transparent boundary condition involving a Dirichlet to Neumann operator. Our analysis emphasizes some strong singularities of the Stokes-Coriolis operator at low tangential frequencies. One of the main features of our work lies in the definition of a Dirichlet to Neumann operator for the Stokes-Coriolis system with data in the Kato space $H^{1/2}_{uloc}$.Comment: 64 page

Perceptual adjustment to time-compressed Speech: a cross-linguistic study

revious research has shown that, when hearers listen to artificially speeded speech, their performance improves over the course of 10-15 sentences, as if their perceptual system was "adapting" to these fast rates of speech. In this paper, we further investigate the mechanisms that are responsible for such effects. In Experiment 1, we report that, for bilingual speakers of Catalan and Spanish, exposure to compressed sentences in either language improves performance on sentences in the other language. Experiment 2 reports that Catalan/Spanish transfer of performance occurs even in monolingual speakers of Spanish who do not understand Catalan. In Experiment 3, we study another pair of languages--namely, English and French--and report no transfer of adaptation between these two languages for English-French bilinguals. Experiment 4, with monolingual English speakers, assesses transfer of adaptation from French, Dutch, and English toward English. Here we find that there is no adaptation from French and intermediate adaptation from Dutch. We discuss the locus of the adaptation to compressed speech and relate our findings to other cross-linguistic studies in speech perception

Labour Market Institutions and Unemployment: Does Finance Matter?

We explore whether finance influences the impact of labour market institutions on unemployment. Using a data set of 18 OECD countries over 1980-2004, we estimate a panel VectorAutoRegressive model. We check whether causalities from labour market variables to unemployment are affected by financial factors. In Belgium, Italy, Australia, Japan and Spain, accounting for financial indicators mitigates the benefits of labour market flexibilization or makes it harmful to employment. In Austria, Canada, Finland and Portugal, it reduces its detrimental impact or makes it beneficial. In Ireland and Netherlands, both effects prevail, depending on the labour market indicator used.unemployment, labour market, financial factors, institutional interactions, panel VAR

The spectrum of the B[e] star BAL224

We present optical spectroscopy of the emission line star BAL 224 (V=17.3, B-V=0.46). This star also named KWBBE 485, [MA93]906 is located at the periphery of the young SMC cluster NGC 330; it is known as a photometric variable with a possible period around 1 day (Balona 1992). Furthermore it was reported as the optical counterpart of the prominent mid-infrared source (MIR1) by Kucinskas et al. (2000), indicating the presence of a dust shell. The star was included in a sample of B-type stars observed using the ESO VLT-FLAMES facilities. The presence of emission lines such as Fe II,[Fe II], [S II] make this object like a B[e] star. The H$alpha$, H$gamma$ and H$delta$ lines show an asymmetrical double-peaked emission profile suggesting the presence of an accretion disk. Moreover the MACHO and OGLE light curves were analyzed; in addition to a long-term variability ($simeq$ 2300d), a short period very close to 1 day has been detected using different methods, confirming the variability previously reported by Balona (1992). Finally the nature of this object is reconsidered.Comment: 4 page

Unemployment and finance: how do financial and labour market factors interact?

sing annual data for 18 OECD countries over the period 1980-2004, we investigate how labour and financial factors interact to determine unemployment by estimating a dynamic panel model using the system generalized method of moments (GMM). We show that the impact of financial variables depends strongly on the labour market context. Increased market capitalization as well as decreased banking concentration reduce unemployment if the level of labour market regulation, union density and coordination in wage bargaining is low. The above financial variables have no effect otherwise. Increasing intermediated credit and banking concentration is beneficial for employment when the degree of labour market regulation, union density and coordination in wage bargaining is high. These results suggest that the respective virtues of ed and market-based finance are crucially tied to the labour market context.Unemployment, institutional complementarities and substituabilities, labour market, financial system.

A new intersecting tunnel structure in the AIMIII[PO3(OH)]2 series for AI = Ag, MIII = In : Analysis of structural relationships.

A new indium hydroxyphosphate containing silver, AgIn[PO3(OH)]2, has been synthesized using hydrothermal method. It crystallizes in the P21/c space group with the cell parameters a = 6.6400(2)Å, b=14.6269(6)Å, c=6.6616(4)A, β=95.681(5)°, V=643.82(6)Å3, Z=4. Its three-dimensional framework, built up of comer-sharing PO3(OH) tetrahedra and InO6 octahedra, presents intersecting tunnels running along and [100] directions, in which the Ag+ cations are located. The presence of hydroxyl groups has been confirmed from IR spectroscopy studies and hydrogen atoms were located from the single crystal X-ray diffraction study. The structural relationships with the other compounds of general formula AΙΜΙΙΙ[PΟ3(OH)]2 are analyz

Preparation-microstructure-property relationships in double-walled carbon nanotubes/alumina composites

Double-walled carbon nanotube/alumina composite powders with low carbon contents (2– 3 wt.%) are prepared using three different methods and densified by spark plasma sintering. The mechanical properties and electrical conductivity are investigated and correlated with the microstructure of the dense materials. Samples prepared by in situ synthesis of carbon nanotubes (CNTs) in impregnated submicronic alumina are highly homogeneous and present the higher electrical conductivity (2.2–3.5 Scm-1) but carbon films at grain boundaries induce a poor cohesion of the materials. Composites prepared by mixing using moderate sonication of as-prepared double-walled CNTs and lyophilisation, with little damage to the CNTs, have a fracture strength higher (+30%) and a fracture toughness similar (5.6 vs 5.4 MPa m1/2) to alumina with a similar submicronic grain size. This is correlated with crack-bridging by CNTs on a large scale, despite a lack of homogeneity of the CNT distribution