La génération de la valeur dans les opérations de capital investissement : proposition d’une revue de la littérature adaptée aux pays émergents.

Le capital investissement (dorénavant CI) est devenu aujourd’hui une classe d’actif omniprésente dans chaque économie, qui va au-delà de la simple intermédiation financière vers une forme hybride d’entreprenariat active. Au Maroc comme dans d’autres pays de l’Afrique du Nord, il devient de plus en plus important de comprendre le fonctionnement et le processus de création de la valeur qui motive la raison d’être de ce type de fonds d’investissement sur le continent. Elément centrale dans la réflexion des capital investisseurs, la réalisation de la création de la valeur est sujette à une assimilation de ses leviers et méthodes, selon la contingente, notamment dans un contexte de marchés émergents. L’objectif de ce papier est de pouvoir proposer une synthèse de la revue de la littérature traitant de la question de la création de la valeur dans les opérations de CI en général et au niveau des pays émergents en particulier

Microwave spectrum of toluene⋅SO2: Structure, barrier to internal rotation, and dipole moment

The microwave spectrum of toluene⋅SO2 was observed with a pulsed beam Fourier‐transform microwave spectrometer. The spectrum displays a‐, b‐, and c‐dipole transitions. The transitions occur as doublets arising from the internal rotation of the methyl group. The transitions were assigned using the principal‐axis method (PAM) internal rotation Hamiltonian with centrifugal distortions. Assuming a threefold symmetry for the internal rotation potential, the barrier height was determined as V3=83.236(2) cm−1. The torsional–rotational spectra of toluene‐CD3⋅SO2 and toluene‐d8⋅SO2 were also assigned. Additional small splittings of the c‐dipole transitions for the normal species and toluene‐CD3⋅SO2 suggest a reorientation tunneling motion of SO2 with respect to the aromatic plane. The moment of inertia data show that the two monomer units are separated by Rcm=3.370(1) Å, with the SO2 located above the aromatic ring. The projection of the C2 axis of SO2 on the aromatic plane makes an angle of τ=47.0(1)° with the C3 axis of toluene. The dipole moment of the complex is μT=1.869(27) D.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69732/2/JCPSA6-98-5-3627-1.pd

The microwave spectrum, structure, and tunneling motion of the sulfur dioxide dimer

The microwave spectrum of (SO2)2 has been reinvestigated using a pulsed beam Fourier‐transform microwave spectrometer. Several new a‐type transitions for the normal species and the a‐type spectra of eight isotopically substituted species were measured. The spectra indicate that the SO2 dimer undergoes a high‐barrier tunneling motion. Based on the analysis used for (H2O)2 by Coudert and Hougen [J. Mol. Spectrosc. 130, 86 (1988)], the internal motion is identified as a geared interconversion motion similar to that displayed by (H2O)2. From the analysis of the moments of inertia of the various isotopic species, an ac plane of symmetry is established for the dimer and the tilt angles of the C2 axes of each subunit relative to the line joining their centers of mass were determined. From Stark effect measurements, μa was redetermined and μc was shown to be nearly zero. Electrostatic calculations using distributed multipoles were carried out to explore the structure of this dimer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70674/2/JCPSA6-94-11-6956-1.pd

Correlation between the tribology of concrete and the rheology of the corresponding mortars

The present work aims to study the possibility of characterizing the pumpability of concrete from the rheology of the derived mortars, i.e. concrete mortar (CM) and concrete equivalent mortar (CEM). As concrete is a material that is heavier than mortar, it is better to carry out tests on mortar. To this end, two test campaigns are presented in this article; the first campaign concerns the formulation of admixed concrete based on two mineral additions, namely limestone fillers and blast furnace slag. The aim of this first campaign was to study the tribological behavior of the formulated concretes. In the second test campaign, the formulations of the mortars were derived from the formulations of the corresponding concretes. Afterwards, a rheological study was carried out on these mortars. Analysis of the results obtained showed that there is a good correlation between the developed concretes and their corresponding CEMs, with fairly high determination coefficients

Correlation between the tribology of concrete and the rheology of the corresponding mortars

The present work aims to study the possibility of characterizing the pumpability of concrete from the rheology of the derived mortars, i.e. concrete mortar (CM) and concrete equivalent mortar (CEM). As concrete is a material that is heavier than mortar, it is better to carry out tests on mortar. To this end, two test campaigns are presented in this article; the first campaign concerns the formulation of admixed concrete based on two mineral additions, namely limestone fillers and blast furnace slag. The aim of this first campaign was to study the tribological behavior of the formulated concretes. In the second test campaign, the formulations of the mortars were derived from the formulations of the corresponding concretes. Afterwards, a rheological study was carried out on these mortars. Analysis of the results obtained showed that there is a good correlation between the developed concretes and their corresponding CEMs, with fairly high determination coefficients

Centrifugal distortions in molecules: An ab initio approach with application to phosphine

Our procedure for employing analytic gradients of ab initio potential energy hypersurfaces in the description of centrifugally distorted molecules is applied to a symmetric top, namely phosphine. Quartic centrifugal spectroscopic coefficients are obtained and are in excellent agreement with the coefficients from the Kivelson and Wilson method for J || z. We proposed a Borel form that enables us to fit the stabilization energies up to J = 80 for the vibrational ground state of phosphine. The sextic spectroscopic constant for J || z is obtained. Both single determinantal (HF/6-31G**) and multideterminantal Moller-Plesset (MP2/6-31G*) surfaces were utilized.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27562/1/0000606.pd

Microwave spectrum, structure, barrier to internal rotation, dipole moment, and deuterium quadupole coupling constants of the ethylene–sulfur dioxide complex

The microwave spectra of the complex between ethylene and sulfur dioxide and nine of its isotopic species have been observed in a Fourier transform microwave spectrometer. The spectra exhibit a and c dipole selection rules; transitions of the normal species and several of the isotopically substituted species occur as tunneling doublets. The complex has a stacked structure with Cs symmetry; the C2H4 and SO2 moieties both straddle the mirror plane with the C2 axis of SO2 crossed at 90 ° to the carbon–carbon bond axis (i.e., only the S atom lies in the symmetry plane). The distance between the centers of mass (Rcm) of C2H4 and SO2 is 3.504(1) Å and the deviation of their planes from perpendicular to Rcm is 21(2) ° and 12(2) °, respectively. The tunneling splittings arise from a rotation of the ethylene subunit in its molecular plane. The barrier to internal rotation is 30(2) cm−1. The dipole moment of the complex is 1.650(3)D. The deuterium nuclear quadrupole coupling constants for C2H3D⋅SO2 are χaa=−0.119(1) MHz, χbb=0.010(1) MHz, and χcc=0.109(1) MHz. The binding energy is estimated to be 490 cm−1 from the pseudo‐diatomic approximation. A distributed multipole electrostatic model is explored to rationalize the structure and binding energies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70892/2/JCPSA6-93-10-7030-1.pd

Applicability and outcome of laparoscopic adrenalectomy for large tumours

Laparoscopic adrenalectomy has been shown to be as safe and effective as conventional open surgery for small and benign adrenal lesions. With increasing experience with laparoscopic adrenalectomy, this approach has become the procedure of choice for the majority of patients requiring adrenalectomy. In our department, from 2011 to 2016, a total of 28 patients with 31 adrenal tumours underwent laparoscopic adrenalectomy regardless of tumour size. Our policy in the department is to exclude adrenal tumours that are potentially malignant or metastatic adrenal tumours for laparoscopic resection. In this a retrospective study, we divided patients into two groups according to tumour size: < 5 or ≥ 5 cm, which was considered as the definition of large adrenal tumours. We compared demographic data and per- and postoperative outcomes. There was no statistical difference between the two groups for per-operative complications (16,6% vs 18,75% , P = 0.71), postoperative complications (16,6% vs 18,75% , P = 0.71), postoperative length of hospital stay (5 vs 8 days P = 0.40), mortality (0% vs 0%) or oncologic outcomes: recurrence and metastasis (8.3% vs 6.25% P = 0.70). The only statistical difference was the operating time, at a mean (SD) 194 (60) vs 237 (71) min (P = 0.039) and the conversion rate (0% vs 12.5% P < 0.01). Laparoscopic adrenalectomy can be done for all patients with adrenal tumours regardless of tumour size, even it needs more time for large tumour but appears to be safe and feasible when performed by experienced surgeons

Origin, distribution, and behaviour of rare earth elements in river bed sediments from a carbonate semi-arid basin (Tafna River, Algeria)

The behaviour and sources of rare earth elements (REE) in river sediments were investigated at ten stations and two dams of the Tafna basin (Northern Algeria) during contrasting hydrological conditions and using a combination of normalisation procedures, REE anomalies, various REE ratios, and multivariate statistical analysis. The ranking and REE concentrations were in the range of other carbonated areas. The classical fractionation of the heavy REE(HREE) erosion pattern, evidenced from upstream to downstream by the La/Yb or Sm/Yb ratios,was disturbed by the presence of dams, which retained the light REE (LREE) in particular. The hydrological conditions, particle size, and geochemical characteristics controlled the REE patterns. The LREE were associated with clay minerals and HREE with coarse silts, whereas carbonate and particulate organic carbon (POC) did not influence the transport downstream. The total concentration of REE in sediments was not strongly affected by anthropogenic inputs from various sources (industrial activities, and domestic or medical wastes). Indeed, some LREE enrichment and anomalies were detected at a few stations and locally for Gd, Tb, and Yb. However, the anthropogenic contribution can partially be hidden by dilution due to particle erosion. High flow increased the LREE and MREE enrichment and LREE/HREE fractionation in some places due to erosion processes and anthropic influences (dam releases and local wastes inputs). Middle REE (MREE) and HREE were the most extractable elements unlike LREE (which are the most concentrated), particularly during high water conditions. Finally, the REE demonstrated the impact of natural processes (hydrological, geochemical, and physical) and some anthropogenic disturbances (waste inputs, fertilisers, and dams). This might inspire to develop such investigations in other similar semi-arid basins undergoing various pressures. The use of local bedrock as a reference and a set of geochemical and statistical tools, is recommended