Search results for "BIF"
showing 10 items of 539 documents
Indoor air pesticide in dwellings of breastfeeding mothers of the Valencian Region (Spain): Levels, exposure and risk assessment
2021
This study assessed the inhalation risk associated with indoor pesticide concentrations in the dwellings of 41 lactating mothers living in the Valencian Region, Spain, who were participants in the BETTERMILK project. Twenty-eight substances were investigated, including pyrethroid (PYRs), organophosphate (OPPs), and organochlorine (OCPs) pesticides. Bifenthrin, cypermethrin, lambda-cyhalothrin, malathion, permethrin and pyrimethanil were detected with frequencies ranging from 2% (malathion) to 80% (cypermethrin), and with an arithmetic mean concentration ranging from 4.1 ng m(-3) (bifenthrin) to 12.1 ng m-(3) (cypermethrin). The indoor air analysis was combined with several surveys to assess…
Desingularization Theory and Bifurcation of Non-elementary Limit Periodic Sets
1998
In the study of the Bogdanov-Takens unfolding, we introduced in 4.3.5.2 the following formulas of rescaling in the phase-space and in the parameter space: $$ x = {r^2}\bar x,y = {r^3}\bar y,\mu = - {r^4},\nu = {r^2}\bar \nu . $$
One-pot synthesis of graphene quantum dots and simultaneous nanostructured self-assembly via a novel microwave-assisted method: impact on triazine re…
2018
One-step methods for fabricating green materials endowed with diverse functions is a challenge to be overcome in terms of reducing environmental risk and cost. We report a fast and easy synthesis of multifunctional materials composed of only fluorescent dots with structural flexibility and high sorption capability. The synthesis consists of a one-pot microwave-assisted reaction for the simultaneous formation of graphene quantum dots (GQDs) from organic precursors and their spontaneous self-assembly forming porous architectures. The GQD-assemblies are robust and no signs of degradation were observed with most organic solvents. The ensuing GQDs and their porous solids were fully characterized…
Transition to turbulence in toroidal pipes
2011
AbstractIncompressible flow in toroidal pipes of circular cross-section was investigated by three-dimensional, time-dependent numerical simulations using a finite volume method. The computational domain included a whole torus and was discretized by up to ${\ensuremath{\sim} }11. 4\ensuremath{\times} 1{0}^{6} $ nodes. Two curvatures $\delta $ (radius of the cross-section/radius of the torus), namely 0.3 and 0.1, were examined; a streamwise forcing term was imposed, and its magnitude was made to vary so that the bulk Reynolds number ranged between ${\ensuremath{\sim} }3500$ and ${\ensuremath{\sim} }14\hspace{0.167em} 700$. The results were processed by different techniques in order to confirm…
On hyperbolic type involutions
2001
We give a bound on the number of hyperbolic knots which are double covered by a fixed (non hyperbolic) manifold in terms of the number of tori and of the invariants of the Seifert fibred pieces of its Jaco-Shalen-Johannson decomposition. We also investigate the problem of finding the non hyperbolic knots with the same double cover of a hyperbolic one and give several examples to illustrate the results.
Ship-in-a-bottle synthesis of triphenylamine inside faujasite supercages and generation of the triphenylamminium radical ion
2005
Abstract The ship-in-a-bottle synthesis of triphenylamine encapsulated within basic X zeolite has been accomplished by reacting sodium diphenylamide with bromobenzene in the presence of a bifunctional palladium (Hartwig–Buchwald conditions). The presence of incarcerated triphenylamine was demonstrated by dissolving the zeolite with concentrated HF and analyzing the organic material in the dichloromethane extract. Laser flash photolysis (266 nm) gives rise to the generation of triphenylamminium radical cation detected as a transient species decaying in hundreds of microseconds. Upon repetitive cyclic voltammograms, zeolite encapsulated triphenylamine shows a reversible oxidation–reduction pr…
2,2′:6′,2″-Terpyridine Trimethylplatinum(IV) Iodide Complexes as Bifunctional Halogen Bond Acceptors
2016
Three new organometallic trimethylplatinum(IV) iodide complexes of 2,2′:6′,2″-terpyridines have been synthesized and characterized by 1H NMR spectroscopy, mass spectrometry, elemental analysis, and single crystal X-ray diffraction analysis. The X-ray crystal structures of PtMe3I(L) complexes 1–3 {L for 1 = 4′-chloro-2,2′:6′,2″-terpyridine, 2 = 4′-(4-cyanophenyl)-2,2′:6′,2″-terpyridine, and 3 = 4′-(4-tolyl)-2,2′:6′,2″-terpyridine} reveal distorted octahedral coordination geometry of the platinum(IV) metal centers with bidentate coordination of the terpyridine ligands. Complexation of 1–3 with iodopentafluorobenzene (IPFB) afforded single-crystal structures of halogen bond (XB) complexes 1a–3…
Socioemotional Wealth and Networking in the Internationalisation of Family SMEs
2021
In internationalisation processes, international expansion exposes family SMEs to external networking and the risks such expansion entails, and perceived threats to their socioemotional wealth (SEW) might restrain their willingness to take these actions. However, very few studies measure SEW and associate it with internationalisation. Considering SEW preservation’s prominence in family SMEs and SMEs’ heavy dependence on networking during internationalisation, we hypothesise that SEW preservation has a negative association and networking has a positive association with the family SMEs’ degree of internationalisation (DOI). We reconstruct four SEW constructs that carry significance for family…
Dynamic instability in absence of dominated splittings.
2006
We want to understand the dynamics in absence of dominated splittings. A dominated splitting is a weak form of hyperbolicity where the tangent bundle splits into invariant subbundles, each of them is more contracted or less expanded by the dynamics than the next one. We first answer an old question from Hirsch, Pugh and Shub, and show the existence of adapted metrics for dominated splittings.Mañé found on surfaces a $C^1$-generic dichotomy between hyperbolicity and Newhouse phenomenons (infinitely many sinks/sources). For that purpose, he showed that without a strong enough dominated splitting along one periodic orbit, a $C^1$-perturbation creates a sink or a source. We generalise that last…
Membrane fatty acid composition and fluidity are involved in the resistance to freezing of Lactobacillus buchneri R1102 and Bifidobacterium longum R0…
2015
International audience; Determinations of membrane fatty acid composition and fluidity were used together with acidification activity and viability measurements to characterize the physiological state after freezing of Lactobacillus buchneri R1102 and Bifidobacterium longum R0175 cells harvested in the exponential and stationary growth phases. For both strains, lower membrane fluidity was achieved in cells harvested in the stationary growth phase. This change was linked to a lower unsaturated-to-saturated fatty acid ratio for both strains and a higher cyclic-to-saturated fatty acid ratio for L. buchneri R1102 alone. These membrane properties were linked to survival and to maintenance of aci…