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BackgroundHyperbaric oxygen (HBO2) therapy has been proposed to treat hypoxaemia and reduce inflammation in COVID-19. Our objective was to analyse safety and efficacy of HBO2in treatment of hypoxaemia in patients with COVID-19 and evaluate time to hypoxaemia correction.MethodsThis was a multicentre, open-label randomised controlled trial conducted in Buenos Aires, Argentina, between July and November 2020. Patients with COVID-19 and severe hypoxaemia (SpO2≤90% despite oxygen supplementation) were assigned to receive either HBO2treatment or the standard treatment for respiratory symptoms for 7 days. HBO2treatment was planned for ≥5 sessions (1 /day) for 90 min at 1.45 atmosphere absolute (ATA). Outcomes were time to normalise oxygen requirement to SpO2≥93%, need for mechanical respiratory assistance, development of acute respiratory distress syndrome and mortality within 30 days. A sample size of 80 patients was estimated, with a planned interim analysis after determining outcomes on 50% of patients.ResultsThe trial was stopped after the interim analysis. 40 patients were randomised, 20 in each group, age was 55.2±9.2 years. At admission, frequent symptoms were dyspnoea, fever and odynophagia; SpO2was 85.1%±4.3% for the whole group. Patients in the treatment group received an average of 6.2±1.2 HBO2sessions. Time to correct hypoxaemia was shorter in treatment group versus control group; median 3 days (IQR 1.0–4.5) versus median 9 days (IQR 5.5–12.5), respectively (p2group at day 3 compared with the control group was 23.2 (95% CI 1.6 to 329.6; p=0.001) Treatment had no statistically significant effect on acute respiratory distress syndrome, mechanical ventilation or death within 30 days after admission.ConclusionOur findings support the safety and efficacy of HBO2in the treatment of COVID-19 and severe hypoxaemia.Trial registration numberNCT04477954.

Two functional protein sequences can sometimes be separated by a fitness valley - a series of low or non-functional intermediate mutations that must be traversed to reach a more optimal or refined function. Time-varying selection pressure modulates evolutionary sampling of such valleys. Yet, how the amplitude and frequency of fluctuating selection influence the rate of protein evolution is poorly understood. Here, we derive a simple equation for the time-dependent probability of crossing a fitness valley as a function of evolutionary parameters: valley width, protein size, mutation rate, and selection pressure. The equation predicts that, under low selection pressure, the valley crossing rate is magnified by a factor that depends exponentially on valley width. However, after a characteristic time set by the evolutionary parameters, the rate rapidly decays. Thus, there is an optimal frequency of selection-pressure fluctuations that maximizes the rate of protein optimization. This result is reminiscent of the resonance frequency in mechanical systems. The equation unites empirical and theoretical results that were previously disconnected, and is consistent with time-dependent in vitro and clinical data. More generally, these results suggest that seasonal and climate oscillations could synchronously drive protein evolution at the resonant frequency across a range of organism hosts and timescales. This theory could also be applied to optimize de novo protein evolution in laboratory directed evolution using time-varying protocols.

Il contributo, muovendo dalle leggi razziali del1939, analizza il tema delle responsabilità italiane nella Shoah

A correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-019-7506-9

We propose for the spin density matrix two parametrizations which automatically fulfil the non-negativity conditions, without setting any bound on the parameters. The first one relies on a theorem, that we prove, and it is rather simple and easily adaptable to some specific reactions, where, for example, parity is conserved or angular momentum conservation entails selection rules. Moreover, in the case when the rank is less than the order of the density matrix, we show how to improve the fits to the data, either by implementing previous suggestions, or by elaborating an alternative method, for which we prove a second theorem. Our second parametrization is a variant of previous treatments, it appears suitable for some particular processes. Moreover, we discuss about the possibility of inferring the elements of the density matrix from the differential decay width. Last, we illustrate various examples of current interest, both in strong and weak decays; some of them may be helpful in the investigation of physics beyond the standard model., Comment: 19 pages

Funding Acknowledgements Type of funding sources: None. Background – Although percutaneous mitral valve repair is an attractive alternative treatment option for patients with severe mitral regurgitation (MR) at high surgical risk, residual MR is commonly observed after the procedure and little is known about its impact on outcomes after MitraClip therapy, expecially in patients with severe left ventricular (LV) impairment. Purpose – The aim of this prospective, observational study was to evaluate the impact of residual MR (MR ≤1+ vs. MR >1+) on long-term outcomes of mitral valve repair with the MitraClip System in high surgical risk patients presenting with moderate-to-severe or severe MR and with severe reduction of LV ejection fraction (EF). Methods – Patients enrolled in the prospective Getting Reduction of Mitral Insufficiency by Percutaneous Clip Implantation (GRASP) with functional MR and EF ≤30% who were eligible at almost five-year follow-up were included in the present analysis. The primary endpoint was death at 5-year follow-up. Also echocardiographic parameters at baseline and 5-year follow-up and rehospitalization rates were assessed. Results – A total of 139 patients were included: 92 (66.2%) with post-procedural residual MR ≤1+ and 47 (33.8%) with residual MR > 1+ (41 patients with residual MR 2+, 5 with residual MR 3+, 1 with residual MR 4+). Comparable clinical and echocardiographic baseline characteristics were observed between the two groups except for NYHA functional class IV and implanted pace-maker (more frequent in patients with residual MR >1+) and previous myocardial infarction (more frequent in patients with residual MR ≤1+). At 5-year follow-up, no significant differences were reported in the primary endpoint (49.6% in patients with residual MR ≤ 1+ vs. 65.3% in patients with residual MR > 1+, p 0.203) and in cardiac death (37.8% in patients with residual MR ≤ 1+ vs. 42.6% in patients with residual MR > 1+, p 0.921). Cox regression analysis identified residual MR > 1+ as an independent predictor of re-hospitalization (HR 0.51, 95% CI 0.28-0.92, p =0.026). At 5-year follow-up, a significant reduction in left ventricular end-systolic volume was observed in patients with residual MR ≤ 1+. Conclusions – At 5-year follow no significant differences in survival emerged in patients with severe LV dysfunction undergoing MitraClip therapy regardless residual MR. Nevertheless residual MR > 1+ emerged as an indipendent predictor of re-hospitalization.

Familial Mediterranean fever (FMF) is the most common autosomal recessive autoinflammatory disease. To date, following the isolation of more than 280 MEFV sequence variants, the genotype-phenotype correlation in FMF patients has been intensively investigated; however, an univocal and clear consensus has not been yet reached. Thus, the aim of this systematic review was to analyze the available literature findings in order to provide to scientific community an indirect estimation of the impact of genetic factors on the phenotypic variability of FMF. This systematic review has been conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. The p.M694V mutation was reported to have a relatively severe clinical course, similarly, patients homozygous for M694I and M680I, or carrying a combination of both at codons 694 and 680, have a severe disease. Also, patients homozygous for M694V and V726A variants experienced more severe clinical picture. Conversely, heterozygous p.V726A and p.E148Q genotypes have been correlated with a milder disease course. At present, doubts remain on the potential pathogenic role of E148Q variant. The heterogenity in clinical FMF manifestations reflects the changes occuring in repertoire of mutations. We believe that clinical criteria and gene tests, enhancing each other, could better support the diagnosis of FMF.

Trillions of microbial cells colonize human body both internally and externally. The prevalent amount of these reside in the gastrointestinal tract (gut microbiome). Gut microflora support the transformation of food nutrients. The products of this modification processes both modulate gastro-intestinal immunity, and influence other organs such as lung and brain. Recently, it was reported the role of micro-RNAs (miRNAs) as regulators in different pathways of the innate and/or adaptive immune responses. Latest studies discussed the aptitude of probiotics strains to balance the host immune response at a post-transcriptional level by controlling miRNAs expression. We speculated a model of lung immune regulation driven by the axis microbiota-microRNAs, involving asthma, acute injury, cancer and COPD. Based on this axis, we propose a novel approach based on the modification of microRNAs expression centered not exclusively on antagomiRs but also on microbiota modification in order to further potentiate their therapeutic effects.

We consider two-body and quasi-two-body decays of the type $f_1 \to f_2 B$, where $f_1$ and $f_2$ are spin-1/2 fermions and $B$ a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay amplitudes, we derive the expression of the differential decay width and of the polarizations of the final spinning particles, both on- and off-shell. We find an intriguing geometrical interpretation of the results about the polarization. We also illustrate some methods for measuring the polarizations of the resonances and for optimizing data analysis. Then we propose applications to semi-leptonic weak decays, with a major attention to the $T$-odd component of the polarization; this may help to find, simultaneously, possible time-reversal violations and hints to physics beyond the standard model. We suggest also a $CPT$ test. Last, we discuss some $T$-odd observables for the production process of $f_1$ and for the study of the strong final state interactions of non-leptonic decays., 19 pages

The aims of this study were: (i) the characterization of the structure of the indigenous microbial community associated with the sediments under study; (ii) the isolation and characterization of microbial consortia able to degrade the aged hydrocarbons contaminating the sediments, and (iii) the assessment of related biodegradation capability of selected consortia. Samples of surface sediments were collected in Priolo Gargallo harbour (Sicily, Italy). The samples were analysed for physical, chemical (GC-FID analysis) and microbiological characteristics (qualitative (16S rDNA clone library) and quantitative (DAPI, CFU and MPN count) analysis). The sediment samples were used for the selection of two microbial consortia (indicated as PSO and PSM) with high biodegradation capacity for crude oil (~95%) and PAHs (~63%) respectively. Genetic analysis showed that Alcanivorax and Cycloclasticus were the dominant genera in both the PSO and PSM consortia. Oil-polluted environments naturally develop an elevated biorecovery potential. The presence of a highly specialized microbial flora (adapted to support the contamination) and their stimulation through favourable induced conditions provides a promising recovery strategy. The chance to identify and select indigenous bacteria and/or consortia with a high biodegradation capacity is fundamental for the development and optimization of bioaugmentation strategies especially for those concerning in situ applications.

Proximal tibia fractures are caused by a complex trauma, and may lead to invalidating sequelae. These fractures are caused by high-energy trauma as indirect forces in varus-valgus, axial compression and combined. The classification of these fractures is fundamental for adequate treatment (Frattini et al. in Musculoskelet. Surg. 93:109–114, 2009, Ref. [1]).

We examine in detail the semileptonic decay [Formula: see text], which may confirm previous hints, from the analogous [Formula: see text] decay, of a new physics beyond the Standard Model. First of all, starting from rather general assumptions, we predict the partial width of the decay. Then we analyze the effects of five possible new physics interactions, adopting in each case five different form factors. In particular, for each term beyond the Standard Model, we find some constraints on the strength and phase of the coupling, which we combine with those found by other authors in analyzing the analogous semileptonic decays of [Formula: see text]. Our analysis involves some dimensionless quantities, substantially independent of the form factor, but which, owing to the constraints, turn out to be strongly sensitive to the kind of nonstandard interaction. We also introduce a criterion thanks to which one can discriminate among the various new physics terms: the left-handed current and the two-Higgs-doublet model appear privileged, with a neat preference for the former interaction. Finally, we suggest a differential observable that could, in principle, help to distinguish between the two cases.

Pain is a highly distressing symptom for patients with advanced cancer. WHO analgesic ladder is widely accepted as a guideline for its treatment. Our aim was to describe pain prevalence among patients diagnosed with advanced non-small-cell lung cancer (NSCLC), impact of pain on quality of life (QoL) and adequacy of pain management. Data of 1021 Italian patients enrolled in three randomised trials of chemotherapy for NSCLC were pooled. QoL was assessed by EORTC QLQ-C30 and LC-13. Analgesic consumption during the 3 weeks following QoL assessment was recorded. Adequacy of pain management was evaluated by the Pain Management Index (PMI). Some pain was reported by 74% of patients (42% mild, 24% moderate and 7% severe); 50% stated pain was affecting daily activities (30% a little, 16% quite a bit, 336 very much). Bone metastases strongly affected presence of pain. Mean global QoL linearly decreased from 64.9 to 36.4 from patients without pain to those with severe pain (P < 0.001). According to PMI, 616 out of 752 patients reporting pain (82%) received inadequate analgesic treatment. Bone metastases were associated with improved adequacy and worst pain with reduced adequacy at multivariate analysis. In conclusion, pain is common in patients with advanced NSCLC, significantly affects QoL, and is frequently undertreated. We recommend that: (i) pain self-assessment should be part of oncological clinical practice; (ii) pain control should be a primary goal in clinical practice and in clinical trials; (iii) physicians should receive more training in pain management; (iv) analgesic treatment deserves greater attention in protocols of anticancer treatment. © 2004 Cancer Research UK.

G eant 4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.

15 pages; International audience; We give a unitary description of T-odd effects in various sectors of atomic, nuclear and particle physics, like elastic scattering, deep inelastic processes and weak decays. This we get thanks to a particular transformation, which suggests a simple and unambiguous procedure for defining the two typical T-odd observables, the azimuthal asymmetry and the normal polarization. This approach allows to revise the two observables quite naturally in various situations, mainly in deep inelastic processes and in weak decays. In the latter case, useful suggestions for phenomenological analyses and an interesting result for normal and transverse polarization are derived.

We consider two different spin asymmetries in Drell–Yan processes generated by the collisions of an unpolarized proton beam on transversely polarized protons: the muon helicity asymmetry and the left–right asymmetry. We calculate the asymmetries in the framework of the QCD improved parton model, taking into account the parton transverse momentum and considering first-order QCD corrections. The muon helicity asymmetry is sensitive to the quark transversity distribution and is nonvanishing even at zero order. On the contrary the left–right asymmetry vanishes at zero order but not at first order in the QCD coupling constant, as a result of the gluon contribution.

A 62-year-old diabetic woman developed permanent neurological deficits in the legs following spinal anaesthesia. MRI showed oedema in the spinal cord and a small intramedullary focus of signal void at the T10 level, with negative density at CT. Intramedullary gas bubbles have not been reported previously among the possible neurological complications of spinal anaesthesia; a combined ischaemic/embolic mechanism is hypothesised.

We discuss the perspectives of measuring direct CP violation parameters in hyperon decays by measurements with proton and/or antiproton beams, to be carried out at various facilities, and in particular we propose new experiments at the Tevatron and at the LHC., 8 pages, latex

We propose to test instanton models of QCD – in particular the single instanton approximation and the Diakonov and Petrov model – against some exact relations inferred from QCD + QED axial anomaly. One of these relations, in chiral limit, is satisfied by the latter model, but not by the former one. More refined tests, obtained beyond the chiral limit, are not fulfilled by the Diakonov and Petrov model.

We try to reconcile the nonrelativistic quark model predictions with deep inelastic experimental and theoretical results about the first moments of the leading twist contributions to the isotriplet unpolarized and polarized nucleon structure functions (which, by the way, in the limit of large Q 2 tend respectively to the Gottfried sum and to the Bjorken sum). To this end we propose a nonperturbative evolution model for such moments, showing that for Q 2 less than 4 GeV 2 they have the same evolution and that, starting from deep inelastic results at large Q 2 , at very small Q 2 the moments match the nonrelativistic quark model predictions.

Marine microorganisms often reach high swimming speeds, either to take advantage of evanescent nutrient patches or to beat Brownian forces. Since this implies that a sizable part of their energetic budget must be allocated to motion, it is reasonable to assume that some fast-swimming microorganisms may increase their nutrient intake by increasing their speed v. We formulate a model to investigate this hypothesis and its consequences, finding the steady state solutions and analyzing their stability. Surprisingly, we find that even modest increases in nutrient absorption may lead to a significant increase of the microbial speed. In fact, evaluations obtained using realistic parameter values for bacteria indicate that the speed increase due to the enhanced nutrient absorption may be quite large., Comment: 20 pages, 6 figures

We use QCD sum rules, together with two numerical algorithms, for predicting masses of first excited states and partial decay widths of ground states in various channels of charmonium. The method, which has already been applied to the pseudoscalar channel, is now extended to the 1P1 channel. We predict the mass of the first excited state, m h c ′ ⋍ 4.355 GeV ; moreover we fix bounds on the partial decay width of the hc-resonance into light hadrons.

We start from a field-theoretical model of zero range approximation to derive three-dimensional relativistic two- and three-body equations on a null plane. We generalize those equations to finite range interactions. We propose a three-body null-plane equation whose form is different from the one presented earlier in the framework of light-cone dynamics. We discuss the choices of the kernels in two- and three-body cases and apply our model to the description of meson and baryon Regge trajectories. Our approach overcomes some theoretical and phenomenological difficulties met in preceding relativized treatments of the three-body problem., 35 pages LaTex, 6 figs (available from disalvo@vaxgea.ge.infn.it)

A surprising feature of many bacterial motors is the apparently conserved form of their torque-frequency relation. Experiments indicate that the torque provided by the bacterial rotary motor is approximately constant over a large range of angular speeds. This is observed in both monotrichous and peritrichous bacteria, independently of whether they are propelled by a proton flux or by a Na+ ion flux. If the relation between angular speed ω and swimming speed is linear, a ω-independent torque implies that the power spent in active motion is proportional to the instantaneous bacterial speed. Using realistic values of the relevant parameters, we show that a constant torque maximizes the volume of the region explored by a bacterium in a resource-depleted medium. Given that nutrients in the ocean are often concentrated in separate, ephemeral patches, we propose that the observed constancy of the torque may be a trait evolved to maximize bacterial survival in the ocean. Fil: Di Salvo, Mario Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Condat, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina

We show that the Politzer theorem on the equations of motion implies approximate constraints on the quark correlator, restricting considerably, for sufficiently large Q^2, the number of independent distribution functions that characterize the internal structure of the nucleon, and of independent fragmentation functions. This result leads us to suggesting an alternative method for determining transversity. Moreover our approach implies predictions on the Q^2-dependence of some azimuthal asymmetries, like Sivers, Qiu-Sterman and Collins asymmetry. Lastly, we discuss some implications on the Burkhardt-Cottingham and Efremov-Leader-Teryaev sum rules., 49 pages, 5 figures

We elaborate two different methods for extracting from data the relative phase of two amplitudes of some sequential decays of baryons. We also relate this phase to a particular physical angle. Moreover, we suggest how to infer some time-reversal (TR) odd observables — in particular, asymmetries — from data. Last, we comment on the Standard Model (SM) predictions of such asymmetries, showing that most of the decays considered are quite suitable for revealing possible new physics (NP) contributions.

We propose some methods for studying hadronic sequential two-body decays involving more spinning particles. It relies on the analysis of T-odd and T-even asymmetries, which are related to interference terms. The latter asymmetries turn out to be as useful as the former ones in inferring time reversal violating observables; these in turn may be sensitive, under some particular conditions, to possible contributions beyond the standard model. Our main result is that one can extract such observables even after integrating the differential decay width over almost all of the available angles. Moreover we find that the correlations based exclusively on momenta are quite general, since they provide as much information as those involving one or more spins. We generalize some methods already proposed in the literature for particular decay channels, but we also pick out a new kind of time reversal violating observables. Our analysis could be applied, for example, to data of LHCb experiment., Comment: 35 pages

We use QCD sum rules for predicting the mass of the η c resonance and the partial decay width into two gammas of the η c resonance, which are poorly known experimentally. To this end we elaborate two numerical algorithms. The former one allows us to extract the mass of the ground state in a given channel of charmonium, if some parameters are known, and the mass of the first excited state, if the mass of the ground state and the coupling constant g 1 of the ground state to the proper quark current are known. The algorithm is applied to the vector channel for determining one free parameter which is common to all channels; moreover, closely examining the relation between g 1 and the mass of the first excited state in that channel suggests a second algorithm for determining g 1 . Applying these algorithms to the pseudoscalar channel leads us to predicting m η ′ c = 3575 −48 +30 MeV and Γ ( η c → γγ ) = 5585 −635 +490 eV, in good agreement with other predictions and with presently available data.

Introduction: In inguinal hernia repair, many complications are due to mesh fixation technique. Therefore, new types of atraumatic methods of fixation have been proposed. In this article, we present the results of a prospective multicentric parallel randomized controlled trial aiming to compare two mesh fixation techniques: fibrin sealant (QUIXIL ®, Omrix Biopharmaceuticals S.A., Belgium) and Lichtenstein technique. Method: Adult patients with primary uncomplicated inguinal hernia were randomized in two groups: fibrin sealant group (FSG) and Lichtenstein group (LTG). The two groups underwent a follow-up of 15 months. Operative time is the primary outcome. Intraoperative and postoperative outcomes were analyzed. Moreover, a differential cost analysis was performed. Patients and evaluators (with exception of the surgeon who treated the patient) were blinded. Results: A total of 102 patients, 50 in FSG and 52 in LTG, were enrolled from January 2009 to June 2010, and two patients were lost to follow-up at the twelfth month. No significant differences in baseline and clinical characteristics were observed in the two groups. Operative time was longer in LTG (median/ interquartile range: 35 min/30-42.5 min vs. 31 min/28-35 min; effect size: 0.65/95 % CI 0.50-0.91; p < 0.05). No differences in intraoperative complications were observed. No significant differences were observed in early complication rate (RR = 0.62; p > 0.05). Numbness rate was lower in the FSG at 1 week (RR = 0.43; p < 0.01) and at 1 month (RR = 0.17; p < 0.05). No significant differences were observed after 6 months. Postoperative pain was lower in the FSG at 1 week (0/0-1 vs. 1/0-2; p < 0.05) and at 1 month (0/0-0 vs. 0/0-1; p < 0.05). Pain disappeared in all patients after 6 months. Analgesic assumption rate was lower in the FSG (RR = 0.42; p < 0.05). Twenty per cent of FSG and 9.62 % of LTG patients were discharged within 12 h; 78 % of FSG and 90.38 % of LTG patients were discharged within 24 h. The only one recurrence we observed was in FSG group. About costs, although fibrin sealant needed for one mesh fixation is about 10 times more costly than the needed sutures, the total costs of the two procedures did not change significantly. This was mainly due to reduction in operative time. Conclusions: The use of fibrin sealant determined a significant reduction in short-term numbness rate and postoperative pain. There was no relevant difference in total costs per patient between the two procedures. © 2012 Springer-Verlag France.

We study how self-propelled organisms administer their energetic resources in order to optimize space exploration. Noting the existence of two very different time scales, we use a quasistatic approximation to analyze the relation between bacterial dynamics and changes in the energy stored by a bacterium. We then find both steady-state and time-dependent solutions for the bacterial speed and stored energy. The model also predicts the volume of the region that a bacterium may visit in a resource-depleted medium.

We propose a model of interactions among «wee» quarks and antiquarks. Our fundamental assumption is that such partons may give rise —through nonperturbative interactions— to pseudoscalar\(q - \bar q\) bosons and to scalar diquarks; in particular we suppose that sea is organized in pseudoscalar\(q - \bar q\) bosons. Some of the interactions that a valence quark has, either with another valence quark or with sea, modify the predictions of the naive quark-parton model about the spin and spin-averaged quark densities. In order to take into account these modifications we have suitably parametrized the probability densities relative to the interactions in question; moreover we have fixed all the parameters involved, in such a way that our model matches some data of nucleon structure functions and of low-energy hadron physics. Our model has some predictive power with respect to other data of deep inelastic scattering, in particular with respect to the recent EMC and NMC data; furthermore some predictions do not depend on the specific parametrizations chosen for the probability densities, but only on the kinds of interactions assumed. The predictions are in good agreement with available data.

We find, under rather general assumptions, that the average spin of the quarks in the proton is very small. We reproduce the EMC result about the proton polarization on the ground of a phenomenologically successful model. We suggest also a valence-sea interaction mechanism for explaining the spin crisis.

Stenosis in the unprotected left main coronary artery (ULMCA) is considered a standard indication for surgical revascularization. Some studies have demonstrated that stenting of the ULMCA is safe and feasible in selected patients. Drug eluting stents (DES) have been shown to be superior to bare metal stents (BMS) in reducing restenosis and major adverse cardiac events (MACE) both in-hospital and at follow-up after treatment of ULMCA disease. Several studies showed that the mid-term prognosis of patients with left main stenting is good, but most of them are limited by small populations and the availability of mid-term results. Thus, we sought to evaluate the very long term impact of DES vs BMS in a large cohort of patients undergoing stent implantation for ULMCA disease in our center.Between June 2002 and June 2008 a total of 354 consecutive patients with ULMCA stenosis were treated with percutaneous coronary intervention with BMS (53 patients) or DES (301 patients) implantation. A multivariable adjustment was provided in order to account for baseline differences between groups.The average clinical follow-up was 551+/-512 days. Overall, MACE rate was significantly lower in the DES group (16.6% vs 26.4%, P=0.02). The beneficial effect was driven by a reduction of death (6.0% vs 9.4%, P=0.11), MI (2.7% vs 3.8%, P=0.33) and target vessel revascularization after DES implantation (9.0 % vs 15.1%, P=0.11). After correcting for independent predictors of adverse events, the adjusted hazard ratios (HRs) for the risk of mortality and myocardial infarction after DES implantation relative to BMS implantation were 0.99 (95% CIs 0.30-3.21, P=0.98) and 0.59 (95% CIs 0.01-3.45, P=0.56), respectively. The adjusted HR for two-year MACE was 0.50 (95 CIs 0.25-1.02), P=0.056, mainly driven by a statistical significant reduction of TVR (HR 0.30 [95 CIs 0.11-0.82], P=0.018].Patients presenting with ULMCA disease, who are treated with DES have a significant reduction in the rate of target lesion revascularization with no increased risk of death or myocardial infarction.

Marine bacteria often reach high swimming speeds, either to take advantage of evanescent nutrient patches or to beat Brownian forces. Since this implies that a sizable part of their energetic budget must be allocated to motion, it is reasonable to assume that some bacteria are able to increase their nutrient intake by increasing their speed v. We formulate a model that uses the concept of internal energy depot originally developed by Schweitzer, Ebeling, and Tilch to investigate this hypothesis. We postulate that the nutrient absorption rate is of the form q(v) = q0 +Av, with q0 and A being constants. If the fraction c of energy spent non-mechanically is low, we find that there is a single stable velocity v1*, but if c is large, there is a critical value of A, Ac, below which only the v = 0 solution is stable. Above the bifurcation point Ac a second stable solution appears, whose value v2* increases monotonically with A. The mechanical efficiency of the molecular motors is also shown to increase with A. The description of the motion is further clarified by the use of the Fokker-Planck formalism. Solutions obtained using realistic parameter values indicate that the speed increase due to the enhanced nutrient absorption may be substantial.

Weak decays of beauty baryons like \Lambda_b (\bar\Lambda_b) into \Lambda (\bar\Lambda) and V (J^P = 1^-), where both decay products are polarized, offer interesting opportunities to perform tests of time reversal and CP violations and of CPT invariance. We propose a model independent parametrization of the angular distribution and of the polarization of the final resonances, by means of the spin density matrix. The transverse component of the polarization is sensitive to time reversal violations, moreover CP-and CPT-sensitive observables are defined., Comment: 14 pages

We try to extend the QCD sum rules for the two-point functions of the quark currents to the case of the pseudoscalar current of the «up» and «down» quarks. The essential ingredient is the coupling of this current to the instantons, whose effect is to make the sum rule more sensitive to the mass of the pion. A phenomenological approach to the problem yields an effective instanton Lagrangian which is consistent with the one required for reproducing quantitatively the ΔI=1/2 rule in the nonleptonic K-meson decay.

A model of interactions between sea quark-antiquark pairs and valence quarks is proposed. The model is simultaneously consistent with some features of the proton and neutron unpolarized and polarized structure functions; furthermore it makes predictions about the polarization of partons inside the nucleon.

In the framework of the Regge representation, we propose a parametrization of the nuclear elastic scattering amplitude which could be very useful at large angles. The formula proposed is widely illustrated and discussed; moreover the advantages of using this representation are exhibited.

We elaborate a phenomenological model for jets in minimum-bias physics; its essential ingredient is the final-state interaction between active and spectator partons. The model, compared with the UA1 experimental data of integrated jet cross-section, results to agree with the data better than the usual cut-off procedure.

We propose an, approach to multiple partonic interactions in which the collision amplitude is defined as a convolution of the elementary parton-parton scattering amplitude over the overlap functions between the initial and final states of the active partons. According to this approach we predict some features of the multiple hard collisions, among them a clean transition from a regime of «low» momentum transfers to one of «high» momentum transfers. Moreover we deduce the total «hard» cross-section, which we compare with the formulae obtained by other authors.

I deduce some properties of the quark correlator, by exploiting the equations of motion. As a first result, at zero order in the coupling constant the correlator depends on just three independent functions; therefore approximate relations can be established among functions defined in the usual parametrizations of the correlator. Secondly, the azimuthal asymmetries which can be attributed to T‐odd functions are suppressed by powers of the QCD hard scale Q. Lastly, higher twist terms are conveniently parametrized in a particular gauge.