On the Production of π+π+\pi^+\pi^+ Pairs in pp Collisions at 0.8 GeV

Data accumulated recently for the exclusive measurement of the $pp\to pp\pi^+\pi^-$ reaction at a beam energy of 0.793 GeV using the COSY-TOF spectrometer have been analyzed with respect to possible events from the $pp \to nn\pi^+\pi^+$ reaction channel. The latter is expected to be the only $\pi\pi$ production channel, which contains no major contributions from resonance excitation close to threshold and hence should be a good testing ground for chiral dynamics in the $\pi\pi$ production process. No single event has been found, which meets all conditions for being a candidate for the $pp \to nn \pi^+\pi^+$ reaction. This gives an upper limit for the cross section of 0.16 $\mu$b (90% C.L.), which is more than an order of magnitude smaller than the cross sections of the other two-pion production channels at the same incident energy

On the SigmaN cusp in the pp -> pK+Lambda reaction

Measurements of the $pp \to pK^+\Lambda$ reaction at $T_p$ = 2.28 GeV have been carried out at COSY-TOF. In addition to the $\Lambda p$ FSI and $N^*$ resonance excitation effects a pronounced narrow structure is observed in the Dalitz plot and in its projection on the $p\Lambda$-invariant mass. The structure appears at the $pp \to$N$K^+\Sigma$ threshold and is interpreted as $\Sigma$N cusp effect. The observed width of 20 MeV/$c^2$ is substantially broader than anticipated from previous inclusive measurements. Angular distributions of this cusp structure are shown to be dissimilar to those in the residual $pK^+\Lambda$ channel, but similar to those observed in the $pK^+\Sigma^0$ channel

Evaluation of the Validity of SAMe-TT2R2 Score in a Cohort of Venous Thromboembolism Patients Treated With Warfarin

Low SAMe-TT2R2 score of <2 was validated as a predictor of optimum anticoagulation control, reflected by mean time in therapeutic range (TTR) above 65% to 70%, among warfarin-treated atrial fibrillation patients. This study aimed to validate the ability of SAMe-TT2R2 score and its individual components in predicting anticoagulation control (mean TTR and clinical events) among a cohort of venous thromboembolism (VTE) patients in Qatar. A total of 295 patients were retrospectively evaluated. There was a trend toward statistical significance in mean TTR between low (<2) and high (≥ 2) SAMe-TT2R2 score groups (P = .05), a difference that was not sustained when a cutoff of 3 was used (ie, a score of 3 or more). Patients with poor INR control (TTR <70%) were numerically less likely to have SAMe-TT2R2 score of <2 compared with those with good INR control, though the difference was not statistically significant (16.7% vs 83.3%, respectively, P = .4). No thromboembolic events were reported, and no association was found between the score and risk of bleeding. Non-Caucasian origin was the only significant predictor of good anticoagulation in the studied cohort. In conclusion, SAMe-TT2R2 score could not predict quality of anticoagulation control in a cohort of VTE patients treated with warfarin in Qatar. Contribution of other clinical factors and whether a different scoring may yield better prediction of anticoagulation control remains to be tested.The authors disclose receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Medical Research Center in Hamad Medical Corporation. The authors would like to thank Mr Walid Mekkawi and Dr Sayed Yameen, senior pharmacists, for their contribution in data collection. The authors disclose receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Medical Research Center in Hamad Medical Corporation.Scopu

Cross section of the pp→K+Σ+npp\to K^+\Sigma^+n reaction close to threshold

We have measured inclusive data on $K^+$-meson production in $pp$ collisions at COSY J\"ulich close to the hyperon production threshold and determined the hyperon-nucleon invariant mass spectra. The spectra were decomposed into three parts: $\Lambda p$, $\Sigma^0p$ and $\Sigma^+n$. The cross section for the $\Sigma^+n$ channel was found to be much smaller than a previous measurement in that excess energy region. The data together with previous results at higher energies are compatible with a phase space dependence.Comment: accepted by Phys. lett. B some typos correcte

Quinoa in Egypt - plant density effects on seed yield and nutritional quality in marginal regions

Grain quinoa is a halophyte crop with potentially increasing cultivation area. Yet, no standards exist for optimum plant density in arid-regions. The aim of this work was to evaluate the effect of planting density on Peruvian valley type of Chenopodium quinoa Willd. cv. CICA from the standpoint of yield and seed quality in marginal area. Two Field experiments were conducted over two consecutive seasons viz., 2015-2016 in a marginal land at El-Fayoum oasis, Egypt with one quinoa cultivar and two planting densities namely, 56.000 plant ha-1(Low) and 167.000 plant ha(High). A complete randomized block design with six replicates was used. Seed yield increased by 34.7% with increase of plant density from 56.000 plant ha-1 to 167.000 plant ha-1. The increase of plant density significantly decreased weight of 1000-seeds and weight of hectoliter. Protein and ash concentrations in seeds increased at low planting density, whereas carbohydrate concentration decreased. However, there were no significant differences between the two planting densities on the seed concentration of the crude fiber or total fat. Regarding effects of plant density on mineral content in quinoa seeds, the calcium and magnesium contents significantly increased at low density compared with high planting density. Meanwhile, no significant effects of plant density on phosphorus, potassium, iron and zinc content in quinoa seeds were detected. Thus, the present study concludes that the plant density that gives higher seed yield is associated with significant reduction in seed quality in terms of protein content. On the other hand, low plant density significantly increased weight of 1000-seeds and hectoliter, which is reflected on the grain size. The latter is considered as a very important parameter for quinoa global market preference.Fil: Eisa, Sayed S.. Faculty Of Agriculture, Ain Shams University, Cairo; EgiptoFil: Abd El Samad, Emad H.. National Research Centre, Egypt; EgiptoFil: Hussin, Sayed A.. Faculty Of Agriculture, Ain Shams University, Cairo; EgiptoFil: Ali, Essam A.. Desert Research Center, Egypt; EgiptoFil: Ebrahim, Mohamed. Faculty Of Agriculture, Ain Shams University, Cairo; EgiptoFil: González, Juan Antonio. Fundación Miguel Lillo; ArgentinaFil: Ordano, Mariano Andrés. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Erazzú, Luis Ernesto. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: El Bordeny, Nasr E.. Faculty Of Agriculture, Ain Shams University, Cairo; EgiptoFil: Abdel-Ati, Ahmed A.. Desert Research Center, Egypt; Egipt

Mixed 2D-3D Halide Perovskite Solar Cells

The 3D-perovskite halides have gained a considerable reputation versus their counterpart semiconductor materials since they achieved a remarkable high-power conversion efficiency of 25.2% within a decade. Perovskite solar cells also have some problems as lattice degradation and sensitivity against moisture, oxygen, and strong irradiation. The perovskite instability is the drawback in front of this emerging technology towards mass production and commercialization. 2D-perovskites, with the general formula A2Bn − 1MnX3n + 1, have been recently introduced to overcome some of the drawbacks of the stability of 3D-perovskites; however, this is at the expense of sacrificing a part of the power conversion efficiency. Mixed 2D/3D perovskites could solve this dilemma towards the way to high stability-efficiency perovskites. The research is expected to obtain highly stable and efficient mixed 2D/3D perovskite solar cells in the few coming years. This chapter reviews 2D-perovskites’ achieved progress, highlighting their properties, current trends, challenges, and future prospects

High resolution study of the Lambda p final state interaction in the reaction p + p -> K+ + (Lambda p)

The reaction pp -> K+ + (Lambda p) was measured at Tp=1.953 GeV and Theta = 0 deg with a high missing mass resolution in order to study the Lambda p final state interaction. The large final state enhancement near the Lambda p threshold can be described using the standard Jost-function approach. The singlet and triplet scattering lengths and effective ranges are deduced by fitting simultaneously the Lambda p invariant mass spectrum and the total cross section data of the free Lambda p scattering.Comment: submitted to Physics Letters B, 10 pages, 3 figure

Comparison of Isoscalar Vector Meson Production Cross Sections in Proton-Proton Collisions

The reaction $pp\to pp\bf \omega$ was investigated with the TOF spectrometer, which is an external experiment at the accelerator COSY (Forschungszentrum J\"ulich, Germany). Total as well as differential cross sections were determined at an excess energy of $93 MeV$ ($p_{beam}=2950 MeV/c$). Using the total cross section of $(9.0\pm 0.7 \pm1.1) \mu b$ for the reaction $pp\to pp\omega$ determined here and existing data for the reaction $pp\to pp\bf \phi$, the ratio $\mathcal{R}_{\phi/\omega}=\sigma_\phi/\sigma_\omega$ turns out to be significantly larger than expected by the Okubo-Zweig-Iizuka (OZI) rule. The uncertainty of this ratio is considerably smaller than in previous determinations. The differential distributions show that the $\omega$ production is still dominated by S-wave production at this excess energy, however higher partial waves clearly contribute. A comparison of the measured angular distributions for $\omega$ production to published distributions for $\phi$ production at $83 MeV$ shows that the data are consistent with an identical production mechanism for both vector mesons

Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the $np\pi^+$ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the $pp\pi^0$ channel we find in the $np\pi^+$ channel a strong influence of the $\Delta$ excitation already at this energy close to threshold. In particular we find a $(3 cos^2\Theta + 1)$ dependence in the pion angular distribution, typical for a pure s-channel $\Delta$ excitation and identical to that observed in the $d\pi^+$ channel. Since the latter is understood by a s-channel resonance in the $^1D_2$ $pn$ partial wave, we discuss an analogous scenario for the $pn\pi^+$ channel

The reaction Δ+N→N+N+ϕ\Delta+N\to N+N+\phi in ion-ion collisions

We study the threshold $\phi$-meson production in the process $\Delta+N\to N+N+\phi$, which appears as a possible important mechanism in high energy nuclei-nuclei collisions. The isotopic invariance of the strong interaction and the selection rules due to P-parity and total angular momentum result in a general and model independent parametrization of the spin structure of the matrix element in terms of three partial amplitudes. In the framework of one-pion exchange model these amplitudes can be derived in terms of the two threshold partial amplitudes for the process $\pi+N\to N+\phi$. We predict the ratio of cross sections for $\phi-$meson production in $pp$- and $\Delta N$-collisions and the polarization properties of the $\phi$-meson, in $\Delta+N\to N+N+\phi$, as a function of a single parameter, which characterizes the relative role of transversal and longitudinal $\phi$-meson polarizations in the process $\pi+N\to N+\phi$.Comment: 10 pages 3 figure