16,235 research outputs found
Vertical Restraints Facilitating Horizontal Collusion: ‘Stretching’ Agreements in a Comparative Approach
This article discusses the approaches of the European Union (EU) and of the United States (US) to the notions of agreement and concerted practice applied to horizontal collusive consequences of vertical restraints. It concludes that networks of vertical restraints blur the
differences between vertical and horizontal agreements; therefore, both options of attack are available for enforcers in the EU and the US context. If the analysed vertical restraints are adopted in parallel by agreement, they should be deemed illegal as long as they restrict
competition producing collusive consequences. In the absence of explicit coordination to adopt the practice, I suggest first looking for a stretched concept of horizontal agreement or a broadly interpreted concept of concerted practice, including unilateral ‘communication’ that
intentionally reduces uncertainty. Even when the analysed practices are adopted individually and not by all firms, they can represent a commitment to focal points, observable by market players, thus amounting to communication of intent. If that is not possible, I propose that an
analysis of market power, incentives, coercion and induction should guide the finding of an
illegal vertical agreement and ground the analysis of the consequences. The agreement/concerted practice path is an appropriate, feasible and coherent way to deal with
vertical restraints facilitating horizontal tacit coordination, but that does not exclude alternative effective enforcement mechanisms
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Unfolding the impacts of transaction-specific investments: Moderation by out-of-thechannel-loop perceptions and achievement orientations
When distribution channel partners make specific investments, tailored to a particular supplier, it could prompt either opportunism or beneficial (e.g., extra-role) behaviors. The impact of the investment in turn may depend on whether the channel partner perceives that it is being left out of the channel loop by the supplier, as well as that partner’s achievement orientation. This study considers a sample of 155 IT professional service firms and finds that their knowledge-intensive, transaction-specific investments (TSIs) encourage distinct behavioral intentions. If they perceive that the supplier is leaving them out of the channel loop, the effects of the TSIs get amplified in relation to opportunistic and extra-role behavioral intentions. Furthermore, the firms’ achievement orientation moderates these influences. Suppliers thus should attend closely to achievement-oriented partners to ensure they do not perceive that they have been left out of the channel loop
Oxytocin makes us trusting but not gullible
Originally known for its role in childbirth and lactation, oxytocin (OT) has recently proved to play a key role in social behavior. Deprived of OT, humans are unable to recognize and to bond to their peers. Inversely, once boosted with OT, people become more caring, trusting and generous. Effect-sizes on trust and generosity were sufficiently large that OT started to be perceived as a natural drug that would make people credulous. But could OT really impede judgment and lead individuals to trust untrustworthy peers? Here we show that oxytocin makes people trusting, but not gullible. Namely, OT did not have a trust-enhancing effect on people who interacted with seemingly unreliable peers. These results emphasize that the effect of OT is much more context-dependent than previously thought. This finding therefore invalidates some of the potential commercial or military applications of oxytocin
An improved limit on the neutrino mass with CMB and redshift-dependent halo bias-mass relations from SDSS, DEEP2, and Lyman-Break Galaxies
We use measurements of luminosity-dependent galaxy bias at several different
redshifts, SDSS at , DEEP2 at and LBGs at , combined with
WMAP five-year cosmic microwave background anisotropy data and SDSS Red
Luminous Galaxy survey three-dimensional clustering power spectrum to put
constraints on cosmological parameters. Fitting this combined dataset, we show
that the luminosity-dependent bias data that probe the relation between halo
bias and halo mass and its redshift evolution are very sensitive to sum of the
neutrino masses: in particular we obtain the upper limit of eV at the 95% confidence level for a
model, with a equal to (1). When we
allow the dark energy equation of state parameter to vary we find
for a general model with the 95% confidence
level upper limit on the neutrino masses at eV. The
constraint on the dark energy equation of state further improves to
when using also ACBAR and supernovae Union data, in addition
to above, with a prior on the Hubble constant from the Hubble Space Telescope.Comment: 9 pages, 6 figures, submitted to PR
Histopathological evaluation of H. Pylori associated gastric lesions in Benin city, Nigeria
Background: Endoscopic biopsy of the gastric mucosa allows early diagnosis, grading, staging and classification of gastric diseases. Helicobacter pylori, has been recognized as a major aetiologic factor for chronic gastritis, benign gastric ulcers and gastric adenocarcinoma and lymphoma. The loco-regional variability in the prevalence of Helicobacter pylori and associated diseases in Nigeria, emphasise the need for evaluation of subsets of a heterogeneous population like oursObjective: To determine the frequency of helicobacter pylori in gastric endoscopic biopsies and document the pathology of gastric lesions commonly associated with Helicobacter pylori infection.Design: Retrospective descriptive study.Settings: University of Benin Teaching Hospital (UBTH), and Biogenics Histopathology Laboratory (a private Histopathology Laboratory), both based in Benin City, Niger Delta region of Nigeria.Subjects: Endoscopic gastric biopsies recorded in the surgical pathology register of the department from 2005-2009 were studied and relevant demographic and clinical information extracted from the registers, original request cards and patient case files. The clinical data and slides processed from paraffin embedded tissue blocks of endoscopic biopsies of gastric lesions seen from year 2005 to 2009 were studied, analyzed and statistically presented.Results: Total number of specimens studied was 142. Chronic gastritis was present in 117(82.39%) specimens; 9(6.34%) were benign gastric ulcers; 3(2.11%) were gastric polyps; and 11(7.75%) were gastric malignancies. Helicobacter pylori, was demonstrated in 55.6% of all specimens. The peak age for Chronic Gastritis and Gastric Cancer is the 6th decade. Amongst patients with chronic gastritis, inflammatory activity was present in 65%; atrophy in 53%; and intestinal metaplasia in 16.6%. All gastric malignancies seen were intestinal type adenocarcinomas.Conclusion: The spectrum of lesions diagnosed in gastric endoscopic biopsy specimens in Benin, their frequency and associations are largely comparable to what has been described elsewhere in Nigeria and Africa.Key words: Helicobacter Pylori; Gastric lesions; Endoscopic biopsies
Popliteus impingement after TKA may occur with well-sized prostheses
To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (1) popliteus impingements after TKA may occur at both the tibia and the femur, and (2) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.
The location of the popliteus in three cadaver knees was measured using computed tomography, before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized, and undersized implants (one size increments).
At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1 +/- 2 mm for normosized implants, and 15.8 +/- 3 mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80A degrees and 120A degrees: 2 +/- 0.4 mm for normosized implants and 2.6 +/- 0.5 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the posterosuperior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).
A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA
Stellar Ages and Metallicities of Central and Satellite Galaxies: Implications for Galaxy Formation and Evolution
Using a large SDSS galaxy group catalogue, we study how the stellar ages and
metallicities of central and satellite galaxies depend on stellar mass and halo
mass. We find that satellites are older and metal-richer than centrals of the
same stellar mass. In addition, the slopes of the age-stellar mass and
metallicity-stellar mass relations are found to become shallower in denser
environments. This is due to the fact that the average age and metallicity of
low mass satellite galaxies increase with the mass of the halo in which they
reside. A comparison with the semi-analytical model of Wang et al. (2008) shows
that it succesfully reproduces the fact that satellites are older than centrals
of the same stellar mass and that the age difference increases with the halo
mass of the satellite. This is a consequence of strangulation, which leaves the
stellar populations of satellites to evolve passively, while the prolonged star
formation activity of centrals keeps their average ages younger. The resulting
age offset is larger in more massive environments because their satellites were
accreted earlier. The model fails, however, in reproducing the halo mass
dependence of the metallicities of low mass satellites, yields
metallicity-stellar mass and age-stellar mass relations that are too shallow,
and predicts that satellite galaxies have the same metallicities as centrals of
the same stellar mass, in disagreement with the data. We argue that these
discrepancies are likely to indicate the need to (i) modify the recipes of both
supernova feedback and AGN feedback, (ii) use a more realistic description of
strangulation, and (iii) include a proper treatment of the tidal stripping,
heating and destruction of satellite galaxies. [Abridged]Comment: 20 pages, 12 figures, submitted for publication in MNRA
The abundance and clustering of dark haloes in the standard Lambda CDM cosmogony
Much evidence suggests that we live in a flat Cold Dark Matter universe with
a cosmological constant. Accurate analytic formulae are now available for many
properties of the dark halo population in such a Universe. Assuming current
``concordance'' values for the cosmological parameters, we plot halo abundance
against redshift as a function of halo mass, of halo temperature, of the
fraction of cosmic matter in haloes, of halo clustering strength, and of the
clustering strength of the z=0 descendants of high redshift haloes. These plots
are useful for understanding how nonlinear structure grows in the model. They
demonstrate a number of properties which may seem surprising, for example: 10^9
solar mass haloes are as abundant at z=20 as L_* galaxies are today; 10^6K
haloes are equally abundant at z=8 and at z=0; 10% of all matter is currently
in haloes hotter than 1 keV, while more than half is in haloes too cool to trap
photo-ionized gas; 1% of all matter at z=15 is in haloes hot enough to ionise
hydrogen; haloes of given mass or temperature are more clustered at higher
redshift; haloes with the abundance of present-day L_* galaxies are equally
clustered at all z10 are more
clustered at z=0 than are L_* galaxies.Comment: 10 pages, 2 ps figures, version to be published in MNRA
Pattern formation in pulsed gas-solid fluidized beds - The role of granular solid mechanics
Under certain conditions, gas-solid fluidized beds are known to develop a structured flow of bubbles when exposed to periodically pulsating air flows. In quasi-two-dimensional beds, periodically rising bubbles form a triangular tessellation in the vertical plane. Bubble nucleation sites at the distributor plate alternate during each cycle. This pattern sets an excellent benchmark for fundamental studies of fluidization. Notably, most common Eulerian descriptions of granular flow do not yet capture this interplay between solid mechanics and fluid-solid momentum exchange, which we show to be instrumental to the dynamic rearrangement of bubbles in a pulsed bed. We report the first successful CFD simulations of structured bubble flows in a deep, quasi-2D geometry using a Eulerian-Lagrangian CFD-DEM framework. Numerical results are in quantitative agreement with experiments. The simulated dynamics reveal that the patterns emerge from the transition of the granular collective behavior between solid-like and fluid-like, which is an outcome of dynamical coupling between gas and particles. The simulated results point out the essential role of solid frictional stresses on inducing and maintaining the formation of bubble patterns. This underscores the value of investigating pulsation-induced patterns as a prime manifestation of the mesoscopic physics underpinning fluidization, and highlights the direction for improving current practices
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