Do followers really matter in Stackelberg competition?

In this note, we consider a generalized T−stage Stackelberg oligopoly. We provide a proof and an interpretation that under the two necessary and sufficient conditions of linear aggregate demand and identical constant marginal costs, followers do not matter for leaders. Leaders act as rational myopic agents, voluntarily ignoring the number of followers and remaining stages, thereby behaving as Cournotian oligopolists. Strategies of incumbent firms are invariant to entry of new cohorts. Their profits can be studied by the way of two discount factors: the first impacting markup and the second impacting output supply. Some implications in terms of welfare and convergence toward competitive equilibrium are derived.Leader’s markup discount factor, linear economy, follower’s output discount factor, myopic behavior

Theoretical investigation of topological ferrimagnetic intertwining double chain

In this paper, a novel trimeric chain approach to organometallic ferrimagnetics is proposed. The inter and intratrimer exchange interaction has been determined to be antiferromagnetic from a theoretical model magnetic susceptibility. The Curie law observed at very low temperature (q = 5.764 K l0) contrasts with significant ferromagnetic behaviour. The magnetic data were fitted with the IDC model. The compounds interestingly exhibit ferrimagnetic interactions with gCu1 =1.81, gCu2 =2.04 and gCu3 =2.43; J1 =-89.93K and J2= -2.68 KIn this paper, a novel trimeric chain approach to organometallic ferrimagnetics is proposed. The inter and intratrimer exchange interaction has been determined to be antiferromagnetic from a theoretical model magnetic susceptibility. The Curie law observed at very low temperature (q = 5.764 K l0) contrasts with significant ferromagnetic behaviour. The magnetic data were fitted with the IDC model. The compounds interestingly exhibit ferrimagnetic interactions with gCu1 =1.81, gCu2 =2.04 and gCu3 =2.43; J1 =-89.93K and J2= -2.68

Pb et As dans des eaux alcalines minières : contamination, comportement et risques (mine abandonnée de Zeïda, Maroc)

Des échantillons d’eau et de matière en suspension ont été prélevés le long de l’oued Moulouya et dans des lacs de carrière au niveau de l’ancien centre minier de Zeïda (Haute Moulouya, Maroc) en vue d’en évaluer la salubrité. Il est en effet important d’établir le degré et les causes éventuelles de dégradation de la qualité de ces eaux, compte tenu de leur usage à des fins tant domestiques qu’agricoles. Des résidus de traitement ont également été échantillonnés dans les haldes abandonnées.L’analyse des distributions et des variations spatio-temporelles des concentrations de Pb et As a permis de mettre en évidence que le centre minier a véritablement un impact sur la qualité des eaux de surface environnantes, malgré le caractère neutre à alcalin du drainage. Aucune ne rejoint les critères de l’Organisation mondiale de la santé en matière de Pb et As dans l’eau potable (10 µg/L), mais près de la moitié souscrit aux normes marocaines (50 µg/L). L’importance de la dégradation varie selon la saison et la localité, et le contraste entre sites a priori non dégradés et sites dégradés n’est pas toujours très prononcé. On observe même des variations à l’inverse des tendances attendues. Les résultats peuvent cependant être réconciliés en tenant compte de l’importance du transport particulaire par rapport au transport dissous au moment et au lieu de l’échantillonnage.Il appert que les minéralisations et les résidus miniers restés sur place peuvent constituer la principale source de pollution des eaux de surface de la région de Zeïda.The Upper Moulouya Basin was the location of extensive lead mining between 1930 and 1985, with three major operations near Aouli, Mibladen and Zeïda. The Moulouya drains about 7.5% of the Moroccan territory and provides drinking and irrigation water to many communities over its more than 500 km path. It is thus important to determine the impact of past mining activities on its water quality, since the mining sites were abandoned with little or no rehabilitation. This paper focuses on the Zeïda area, the uppermost of these mining centres on the Moulouya.About 630,172 t of lead concentrates (40‑70% Pb) were produced between 1972 and 1985 at Zeïda. Lead was mined from carbonate and sulphide mineral deposits (cerussite, 70%; galena, 30%) mixed with barite in stratiform ore bodies hosted by Permo-Triassic arkoses. Mining left 12 Mt and 70 Mt of tailings and wastes in fully exposed piles on each side of the Moulouya, as well as a dozen water-filled open-stopes. Mine drainage is of neutral pH, thanks to the low content of residual sulphide minerals and the availability of carbonate in the tailings and host rock. The river and some quarry-lakes are tapped to fulfill domestic, agricultural and stock-breeding needs. One lake is used to directly feed Zeïda’s water network (pop. 3,000), without any water treatment.The Moulouya, upstream and downstream of Zeïda, and four lakes were sampled twice in 2002 (dry period: February; wet period: April). Temperature, electric conductivity (EC), Eh and pH were measured in the field. Samples were filtered through 0.45 µm membranes. The filtrates were preserved with 4% HNO3 and kept at 4°C until analysis. The filters and their particulate fraction, as well as a composite sample of the tailings, were dried and kept dry until dissolution and analysis. All measurements were performed by ICP-MS and capillary electrophoresis analyses.Lead and arsenic are well above « normal » concentrations in the tailings, at 5,547 g/t and 192 g/t, respectively. These elements are clear threats to population health, since dust from unstabilized tailings can be dispersed by wind and rain waters, contaminating agricultural soils and surface waters, and eventually leading to cases of saturnism or arsenical intoxication in the population. All Pb and As concentrations measured in the waters sampled are above the World Health Organisation criteria for drinking water (10 µg/L for Pb and As). Nevertheless, about half of these measurements meet the Moroccan criteria (50 µg/L). All samples show near neutral or slightly basic pH values (7.2-8.9). EC is also high (> 1,000 µS/cm).As and Pb are largely associated with the particulate fraction (> 80% of total As and Pb), except for As in two lakes (< 40%). Overall, their concentrations are higher in the Zeïda area than upstream in the Moulouya. However, this is a tendency rather than a rule, because the differences are often small (< 50%) and suffer exceptions. For instance, Pb concentrations are 60% lower than the so-called uncontaminated reference station, in two quarry-lakes sampled during the wet period. The occasional lack of significant and consistent contrast between an obviously degraded environment and a pristine site was unexpected. The results were therefore further investigated, in order to identify possible explanations for the apparent discrepancies.Coherency in the data set emerges when one considers the relative importance of dissolved and particulate transport in the various types of environments sampled. Using this interpretation scheme, EC is considered as an indicator of solute transportation, since EC is a function of dissolved ionic components. Total Pb is regarded as an indicator of particulate transportation, since Pb is strongly adsorbed to particulate substrates at the pH observed. Following these assumptions, particulate transport appears to dominate over dissolved transportation in the Moulouya. Total Pb increases by factors of 3.4 and 9.8 from dry to wet periods, whereas EC decreases by 0.7-0.8, as a result of rain dilution. In two of the four lakes, dissolved transport is comparatively more important, since EC does not change significantly and total Pb shows only a small increase from the dry to the wet period. In these lakes, the dissolved input during the rainy period appears to be large enough to keep EC at its previous value, without significant dilution, as opposed to what is going on in the Moulouya. In the two other lakes, both EC and total Pb decrease from the dry to the wet period, pointing to dilution effects greater than either dissolved or particulate mobilization.Apparent discrepancies in the intensity and direction of variations are explained when prevailing modes of dispersion are taken into account. For instance, the enrichment factor of total Pb in the Moulouya, downstream of Zeïda, jumps from 1.1 (dry) to 3.2 (wet), with respect to the reference station. Meanwhile, EC increases only from 1.2 (dry) to 1.5 (wet). The greater increase of total Pb over EC is explained by prevalent particulate transport. In another case, the enrichment of EC with respect to the reference station, in two lakes, increases from 14.2 and 20.4 (dry) to 20.1 and 27.9 (wet) while total Pb enrichment decreases from 2.0 and 2.0 (dry) to 1.6 and 1.3 (wet). Here, the prevalence of dissolved transport in these two lakes, combined with particulate transport at the reference station, allow for a strong increase in the EC parameter, concurrent with a weak increase in total Pb. Finally, in the lakes where both dissolved and particulate transport are presumably minor, total Pb undergoes enrichment with respect to the reference station, in the dry period (by 3.4 and 1.8), whereas depletion characterizes the wet period (0.6 in both lakes). In this case, enrichment is likely the result of evaporation during the dry season, and depletion the result of dilution by rain during the wet period. These two types of lake behave differently because they are located next to residual mineral deposits (likely with more soluble phases), have short travel distances and thus fewer contacts with adsorbing substrates, which is not the case for the other two lakes

Callus Induction from Carob (Ceratonia siliqua L.) Seedlings and Leaves of Mature Tree

Callus induction was successfully carried out from several explants of carob (Ceratonia siliqua L.). Callogenesis from the apex was tested on three different media containing Woody Plant Medium (WPM), Murashige and Skoog (MS) or Schenk and Hildebrandt (SH) macronutrients supplemented with two different hormonal solutions: benzylaminopurine (BAP) at 4.44 µM alone, or 2.22 µM of BAP plus 5 µM of 2-naphthalineacetic acid (NAA). Primary callus formation was obtained on a medium containing 88% WPM macronutrients. Callus formation from other parts of the plant was as follows: − Cotyledon embryos extracted from immature seeds (85% success rate on WPM medium, containing 4.44 µM BAP and 5 µM NAA); − Cotyledon leaves taken from 7-day-old seedlings, obtained from in vitro germination of seeds (62% success rate on WPM medium, containing 4.44 µM BAP and 5 µM NAA); − Hypocotyls taken from 7-day-old seedlings (55% success rate on WPM containing 2.22 µM BAP and 5 µM NAA); − Differentiated leaves taken from mature tree (84% success rate on WPM medium, containing 4.44 µM of BA and 2.26 µM of NAA). In general, production of primary calli and their growth after transplantation was better on WPM medium supplemented with 2.5 µM NAA and 2.22 µM BAP

Evaluation of Azido 3-Deoxy- d - Manno-oct-2-ulosonic Acid (Kdo) Analogues for Click Chemistry-Mediated Metabolic Labeling of Myxococcus xanthus DZ2 Lipopolysaccharide

[Image: see text] Metabolic labeling paired with click chemistry is a powerful approach for selectively imaging the surfaces of diverse bacteria. Herein, we explored the feasibility of labeling the lipopolysaccharide (LPS) of Myxococcus xanthus—a Gram-negative predatory social bacterium known to display complex outer membrane (OM) dynamics—via growth in the presence of distinct azido (-N(3)) analogues of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo). Determination of the LPS carbohydrate structure from strain DZ2 revealed the presence of one Kdo sugar in the core oligosaccharide, modified with phosphoethanolamine. The production of 8-azido-8-deoxy-Kdo (8-N(3)-Kdo) was then greatly improved over previous reports via optimization of the synthesis of its 5-azido-5-deoxy-d-arabinose precursor to yield gram amounts. The novel analogue 7-azido-7-deoxy-Kdo (7-N(3)-Kdo) was also synthesized, with both analogues capable of undergoing in vitro strain-promoted azide–alkyne cycloaddition (SPAAC) “click” chemistry reactions. Slower and faster growth of M. xanthus was displayed in the presence of 8-N(3)-Kdo and 7-N(3)-Kdo (respectively) compared to untreated cells, with differences also seen for single-cell gliding motility and type IV pilus-dependent swarm community expansion. While the surfaces of 8-N(3)-Kdo-grown cells were fluorescently labeled following treatment with dibenzocyclooctyne-linked fluorophores, the surfaces of 7-N(3)-Kdo-grown cells could not undergo fluorescent tagging. Activity analysis of the KdsB enzyme required to activate Kdo prior to its integration into nascent LPS molecules revealed that while 8-N(3)-Kdo is indeed a substrate of the enzyme, 7-N(3)-Kdo is not. Though a lack of M. xanthus cell aggregation was shown to expedite growth in liquid culture, 7-N(3)-Kdo-grown cells did not manifest differences in intrinsic clumping relative to untreated cells, suggesting that 7-N(3)-Kdo may instead be catabolized by the cells. Ultimately, these data provide important insights into the synthesis and cellular processing of valuable metabolic labels and establish a basis for the elucidation of fundamental principles of OM dynamism in live bacterial cells

Weekends-off efavirenz-based antiretroviral therapy in HIV-infected children, adolescents and young adults (BREATHER): Extended follow-up results of a randomised, open-label, non-inferiority trial

BACKGROUND: Weekends off antiretroviral therapy (ART) may help engage HIV-1-infected young people facing lifelong treatment. BREATHER showed short cycle therapy (SCT; 5 days on, 2 days off ART) was non-inferior to continuous therapy (CT) over 48 weeks. Planned follow-up was extended to 144 weeks, maintaining original randomisation. METHODS: BREATHER was an open-label, non-inferiority trial. Participants aged 8-24yrs with virological suppression on efavirenz-based first-line ART were randomised 1:1, stratified by age and African/non-African sites, to remain on CT or change to SCT. The Kaplan-Meier method was used to estimate the proportion of participants with viral rebound (confirmed VL≥50 copies/mL) under intent-to-treat at 48 weeks (primary outcome), and in extended follow-up at 96, 144, and 192 weeks. SCT participants returned to CT following viral rebound, 3 VL blips or discontinuation of efavirenz. FINDINGS: Of 199 participants (99 SCT, 100 CT), 97 per arm consented to extended follow-up. Median follow-up was 185.3 weeks (IQR 160.9-216.1). 69 (70%) SCT participants remained on SCT at last follow-up. 105 (53%) were male, baseline median age 14 years (IQR 12-18), median CD4 count 735 cells/μL (IQR 576-968). 16 SCT and 16 CT participants had confirmed VL≥50 copies/mL by the end of extended follow-up (HR 1.00, 95% CI 0.50-2.00). Estimated difference in percentage with viral rebound (SCT minus CT) by week 144 was 1.9% (90% CI -6.6-10.4; p = 0.72) and was similar in a per-protocol analysis. There were no significant differences between arms in proportions of participants with grade 3/4 adverse events (18 SCT vs 16 CT participants; p = 0.71) or ART-related adverse events (10 vs 12; p = 0.82). 20 versus 8 serious adverse events (SAEs) were reported in 16 SCT versus 4 CT participants, respectively (p = 0.005 comparing proportions between groups; incidence rate ratio 2.49, 95%CI 0.71-8.66, p = 0.15). 75% of SAEs (15 SCT, 6 CT) were hospitalisations for a wide range of conditions. 3 SCT and 6 CT participants switched to second-line ART following viral failure (p = 0.50). CONCLUSIONS: Sustainable non-inferiority of virological suppression in young people was shown for SCT versus CT over median 3.6 years. Standard-dose efavirenz-based SCT is a viable option for virologically suppressed HIV-1 infected young people on first-line ART with 3-monthly VL monitoring. TRIAL REGISTRATION: EudraCT 2009-012947-40 ISRCTN 97755073 ClinicalTrials.gov NCT01641016

Motile sperm organelle morphology examination (MSOME): intervariation study of normal sperm and sperm with large nuclear vacuoles

<p>Abstract</p> <p>Background</p> <p>Although the motile sperm organelle morphology examination (MSOME) was developed only as a selection criterion, its application as a method for classifying sperm morphology may represent an improvement in evaluation of semen quality, with potential clinical repercussions. The present study aimed to evaluate individual variations in the motile sperm organelle morphology examination (MSOME) analysis after a time interval.</p> <p>Methods</p> <p>Two semen samples were obtained from 240 men from an unselected group of couples undergoing infertility investigation and treatment. Mean time interval between the two semen evaluations was 119 +/- 102 days. No clinical or surgical treatment was realized between the two observations. Spermatozoa were analyzed at greater than or equal to 8400× magnification by inverted microscope equipped with DIC/Nomarski differential interference contrast optics. At least 200 motile spermatozoa per semen sample were evaluated and percentages of normal spermatozoa and spermatozoa with large nuclear vacuoles (LNV/one or more vacuoles occupying >50% of the sperm nuclear area) were determined. A spermatozoon was classified as morphologically normal when it exhibited a normal nucleus (smooth, symmetric and oval nucleus, width 3.28 +/- 0.20 μm, length 4.75 +/- 0.20 μm/absence of vacuoles occupying >4% of nuclear area) as well as acrosome, post-acrosomal lamina, neck and tail, besides not presenting cytoplasm around the head. One examiner, blinded to subject identity, performed the entire study.</p> <p>Results</p> <p>Mean percentages of morphologically normal and LNV spermatozoa were identical in the two MSOME analyses (1.6 +/- 2.2% vs. 1.6 +/- 2.1% <it>P </it>= 0.83 and 25.2 +/- 19.2% vs. 26.1 +/- 19.0% <it>P </it>= 0.31, respectively). Regression analysis between the two samples revealed significant positive correlation for morphologically normal and for LNV spermatozoa (r = 0.57 95% CI:0.47-0.65 <it>P </it>< 0.0001 and r = 0.50 95% CI:0.38-0.58 <it>P </it>< 0.0001, respectively).</p> <p>Conclusions</p> <p>The significant positive correlation and absence of differences between two sperm samples evaluated after a time interval with respect to normal morphology and LNV spermatozoa indicated that MSOME seems reliable (at least for these two specific sperm forms) for analyzing semen. The present result supports the future use of MSOME as a routine method for semen analysis.</p