1,188 research outputs found
On the asymptotic reduction of a bifurcation equation for edge-buckling instabilities
Weakly clamped uniformly stretched thin elastic plates can experience edge buckling when subjected to a transverse pressure. This situation is revisited here for a circular plate, under the assumption of finite rotations and negligible bending stiffness in the pre-buckling range. The eigenproblem describing this instability is formulated in terms of two singularly perturbed fourth-order differential equations involving the non-dimensional bending stiffness ε>0. By using an extension of the asymptotic reduction technique proposed by Coman and Haughton (Acta Mech 55:179–200, 2006), these equations are formally reduced to a simple second-order ordinary differential equation in the limit ε→0+. It is further shown that the predictions of this reduced problem are in excellent agreement with the direct numerical simulations of the original bifurcation equations
The geometric algebra of Fierz identities in arbitrary dimensions and signatures
We use geometric algebra techniques to give a synthetic and computationally
efficient approach to Fierz identities in arbitrary dimensions and signatures,
thus generalizing previous work. Our approach leads to a formulation which
displays the underlying real, complex or quaternionic structure in an explicit
and conceptually clear manner and is amenable to implementation in various
symbolic computation systems. We illustrate our methods and results with a few
examples which display the basic features of the three classes of pin
representations governing the structure of such identities in various
dimensions and signatures.Comment: 77 pages; version published in JHEP in 201
Laparoscopic re-interventions for bile duct injuries
Clinica Chirurgie II, Timișoara, România, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Lucrarea prezintă 2 cazuri exemplificate cu filme video în care intervenţia chirurgicală laparoscopică a fost indicată pentru rezolvarea unor suferinţe
biliare postcolecistectomie pe cale clasică. Primul caz a fost o pacientă cu colecistectomie clasică incompletă la care s-a efectuat totalizarea colecistectomiei pe cale laparoscopică la două luni după intervenţia clasică. Acest caz susţine ideea din literatura actuală conform căreia vechiul termen de
neocolecist corespundea unor colecistectomii incomplete. Abordul laparoscopic este posibil, dar recomandabil în centre cu multă experienţă în chirurgia laparoscopică. Al doilea caz a fost o pacientă cu o leziune de coledoc după o colecistectomie clasică. Această leziune a fost reparată laparoscopic
în urgenţă la 8 zile după prima intervenţie. Evoluţia ambelor paciente a fost simplă, dovedind că în unele cazuri reintervenţia pe cale laparoscopică
este fezabilă, sigură şi benefică pentru pacient.This paper presents 2 case reports illustrated by surgical video. In both cases laparoscopic intervention was indicated for repair of bile duct injuries
produced during open cholecystectomy. The first case describes a female patient who underwent an incomplete open cholecystectomy. Two months
after the first intervention cholecystectomy was completed by the laparoscopic approach. This case supports the idea circulating in the actual medical
literature that postoperative dilatation of cystic duct (neocholecyst) is the consequence of the incomplete cholecystectomy. Laparoscopic approach is
possible but can be recommended only in centers with experience in minimally invasive surgery. The second case was a patient with bile duct injury
after classic cholecystectomy. This lesion was repaired in emergency by laparoscopic approach 8 days after the first operation. The evolution of both
patients was uneventful, therefore proving that in selected cases laparoscopic re- intervention is a safe and feasible treatment option
Convergence and multiplicities for the Lempert function
Given a domain , the Lempert function is a
functional on the space Hol (\D,\Omega) of analytic disks with values in
, depending on a set of poles in . We generalize its definition
to the case where poles have multiplicities given by local indicators (in the
sense of Rashkovskii's work) to obtain a function which still dominates the
corresponding Green function, behaves relatively well under limits, and is
monotonic with respect to the indicators. In particular, this is an improvement
over the previous generalization used by the same authors to find an example of
a set of poles in the bidisk so that the (usual) Green and Lempert functions
differ.Comment: 24 pages; many typos corrected thanks to the referee of Arkiv for
Matemati
In vitro evaluation on HeLa cells of protective mechanisms of probiotic lactobacilli against Candida clinical isolates
Aims: To characterize in vitro the ability of human Lactobacillus strains to inhibit the adhesion, to displace and to compete with clinically isolated Candida strains.
Methods and Results: Three types of assays were performed to determine the inhibitory effect of Lactobacillus plantarum 319, Lactobacillus rhamnosus IMC 501, Lactobacillus paracasei IMC 502 and a specific probiotic combination
(SYNBIO) on adhesion of Candida pathogens to HeLa cells: blockage by exclusion (lactobacilli and HeLa followed by pathogens), competition (lactobacilli, HeLa and pathogens together) and displacement (pathogens and HeLa followed by the addition of lactobacilli). Bacterial adhesion to HeLa was quantified by microscopy after May-Grunwald/Giemsa stain. The inhibition results highlight a significant (P < 0.05) competition of the considered probiotics against all the Candida strains. The results suggest that the probiotic strains used in this study could prevent colonization of the urogenital tract by
relevant pathogens such as Candida strains through barrier and interference mechanisms (mainly displacement and competition), but the degree of inhibition of adhesion was bacterial strain-dependent.
Conclusions: The results support the potential of these Lactobacillus probiotic strains as anti-infective agents in the vagina and encourage further studies about their capacity to prevent and manage urogenital tract infections in females.
Significance and Impact of the Study: To optimize the defensive properties of the vaginal microbiota, improving the health of many women by probiotic intervention
Pluricomplex Green and Lempert functions for equally weighted poles
For a domain in , the pluricomplex Green function with
poles is defined as .
When there is only one pole, or two poles in the unit ball, it turns out to be
equal to the Lempert function defined from analytic disks into by . It is known
that we always have . In the more general case where we
allow weighted poles, there is a counterexample to equality due to Carlehed and
Wiegerinck, with equal to the bidisk.
Here we exhibit a counterexample using only four distinct equally weighted
poles in the bidisk. In order to do so, we first define a more general notion
of Lempert function "with multiplicities", analogous to the generalized Green
functions of Lelong and Rashkovskii, then we show how in some examples this can
be realized as a limit of regular Lempert functions when the poles tend to each
other. Finally, from an example where in the case of
multiple poles, we deduce that distinct (but close enough) equally weighted
poles will provide an example of the same inequality. Open questions are
pointed out about the limits of Green and Lempert functions when poles tend to
each other.Comment: 25 page
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