Electronic decoupling of polyacenes from the underlying metal substrate by sp ³ carbon atoms

We report on the effect of sp3 hybridized carbon atoms in acene derivatives adsorbed on metal surfaces, namely decoupling the molecules from the supporting substrates. In particular, we have used a Ag(100) substrate and hydrogenated heptacene molecules, in which the longest conjugated segment determining its frontier molecular orbitals amounts to five consecutive rings. The non-planarity that the sp3 atoms impose on the carbon backbone results in electronically decoupled molecules, as demonstrated by the presence of charging resonances in dI/dV tunneling spectra and the associated double tunneling barriers, or in the Kondo peak that is due to a net spin S=1/2 of the molecule as its LUMO becomes singly charged. The spatially dependent appearance of the charging resonances as peaks or dips in the differential conductance spectra is further understood in terms of the tunneling barrier variation upon molecular charging, as well as of the different orbitals involved in the tunneling process

Genetic diversity and stability of groundnut mini-core collections for early and late leaf spot resistance in Nigeria

Disease epidemics of early and late leaf spots (ELS and LLS, respectively) are affected by weather patterns such as hot and wet conditions, making them prevalent in the Guinea and Sudan Savanna zones of Nigeria. The objective of this research was to determine the genetic diversity and stability of groundnut ( Arachis hypogaea L.) mini-core collections for ELS and LLS in Nigeria. The collections were evaluated at Bayero University Kano (2015, 2016 and 2017) and Minjibir (2017) during the rainy seasons. The data collected were analysed by a mixed model and Cluster analysis was carried out to summarise relationships among the mini-core collections. Significant differences were observed between the lines for kernel yield, ELS and LLS resistance. The highest kernel yield was recorded by ICG 12988 (1225 kg ha-1). The highest yielding check variety was Samnut 24, with a kernel yield of 805 kg ha-1. Lines with low ratings for ELS and LLS were in cluster one but had the lowest mean kernel yield; followed by Cluster 2 with a similar trend. Two lines, ICG 12988 and ICG 12989, were grouped in Cluster 10, which had the highest mean yield (1107 kg ha-1), with ELS and LLS rating of 3 and 4, respectively. Check varieties such as Samnut 22, 24 and 25 were grouped in Cluster 9 and are moderately tolerant to leaf spots; while Samnut 26, which is a more recent improved variety was in Cluster 7 with moderate resistance to leaf spots. There was a significant line 7 environment interaction for kernel yield. ICG 12988 and ICG 12989 were highly unstable; while ICG 2019 was the most stable line followed by ICG 12697, ICG 3312 and ICG 8567. In general, results of the current study show a linkage between kernel yield and leaf spots diseases. Therefore, special breeding techniques such as backcrossing or marker-assisted backcrossing are required to improve lines identified with low yield but high resistance or high yield with low resistance.Les \ue9pid\ue9mies de maladies des taches foliaires pr\ue9coces et tardives (ELS et LLS, respectivement) sont affect\ue9es par des conditions m\ue9t\ue9orologiques telles que des conditions chaudes et humides, ce qui les rend r\ue9pandues dans les zones de savane de la Guin\ue9e et du Soudan au Nigeria. L\u2019objectif de cette recherche \ue9tait de d\ue9terminer la diversit\ue9 g\ue9n\ue9tique et la stabilit\ue9 des collections de mini-noyaux d\u2019arachide ( Arachis hypogaea L.) pour ELS et LLS au Nigeria. Les collections ont \ue9t\ue9 \ue9valu\ue9es \ue0 Bayero University Kano (2015, 2016 et 2017) et Minjibir (2017) pendant les saisons des pluies. Les donn\ue9es recueillies ont \ue9t\ue9 analys\ue9es par un mod\ue8le mixte et une analyse par grappes a \ue9t\ue9 effectu\ue9e pour r\ue9sumer les relations entre les collections mini-core. Des diff\ue9rences significatives ont \ue9t\ue9 observ\ue9es entre les lign\ue9es pour le rendement en grains, la r\ue9sistance ELS et LLS. Le rendement en grains le plus \ue9lev\ue9 a \ue9t\ue9 enregistr\ue9 par ICG 12988 (1225 kg ha-1). La vari\ue9t\ue9 t\ue9moin la plus performante \ue9tait Samnut 24, avec un rendement en grains de 805 kg ha-1. Les lign\ue9es avec de faibles notes pour ELS et LLS \ue9taient dans la grappe un mais avaient le rendement moyen du noyau; suivi du Cluster 2 avec une tendance similaire. Deux lign\ue9es, ICG 12988 et ICG 12989, ont \ue9t\ue9 regroup\ue9es dans le groupe 10, qui avait le rendement moyen le plus \ue9lev\ue9 (1107 kg ha-1), avec une cote ELS et LLS de 3 et 4, respectivement. Les vari\ue9t\ue9s de contr\uf4le telles que Samnut 22, 24 et 25 ont \ue9t\ue9 regroup\ue9es dans le groupe 9 et sont mod\ue9r\ue9ment tol\ue9rantes aux taches foliaires; tandis que Samnut 26, qui est une vari\ue9t\ue9 am\ue9lior\ue9e plus r\ue9cente, appartenait au groupe 7 avec une r\ue9sistance mod\ue9r\ue9e aux taches foliaires. Il y avait une interaction ligne 7 environnement significative pour le rendement du noyau. ICG 12988 et ICG 12989 \ue9taient tr\ue8s instables; tandis que ICG 2019 \ue9tait la lign\ue9e la plus stable, suivie par ICG 12697, ICG 3312 et ICG 8567. En g\ue9n\ue9ral, les r\ue9sultats de la pr\ue9sente \ue9tude montrent un lien entre le rendement des grains et les maladies des taches foliaires. Par cons\ue9quent, des techniques de s\ue9lection sp\ue9ciales telles que le r\ue9trocroisement ou le r\ue9trocroisement assist\ue9 par marqueur sont n\ue9cessaires pour am\ue9liorer les lign\ue9es identifi\ue9es avec un faible rendement mais une r\ue9sistance \ue9lev\ue9e ou un rendement \ue9lev\ue9 avec une faible r\ue9sistance

Low-lying quadrupole collective states of the light and medium Xenon isotopes

Collective low lying levels of light and medium Xenon isotopes are deduced from the Generalized Bohr Hamiltonian (GBH). The microscopic seven functions entering into the GBH are built from a deformed mean field of the Woods-Saxon type. Theoretical spectra are found to be close to the ones of the experimental data taking into account that the calculations are completely microscopic, that is to say, without any fitting of parameters.Comment: 8 pages, 4 figures, 1 tabl

Association of Lipoprotein(a) With Atherosclerotic Plaque Progression

BACKGROUND: Lipoprotein(a) [Lp(a)] is associated with increased risk of myocardial infarction, although the mechanism for this observation remains uncertain. OBJECTIVES: This study aims to investigate whether Lp(a) is associated with adverse plaque progression. METHODS: Lp(a) was measured in patients with advanced stable coronary artery disease undergoing coronary computed tomography angiography at baseline and 12 months to assess progression of total, calcific, noncalcific, and low-attenuation plaque (necrotic core) in particular. High Lp(a) was defined as Lp(a) ≥ 70 mg/dL. The relationship of Lp(a) with plaque progression was assessed using linear regression analysis, adjusting for body mass index, segment involvement score, and ASSIGN score (a Scottish cardiovascular risk score comprised of age, sex, smoking, blood pressure, total and high-density lipoprotein [HDL]–cholesterol, diabetes, rheumatoid arthritis, and deprivation index). RESULTS: A total of 191 patients (65.9 ± 8.3 years of age; 152 [80%] male) were included in the analysis, with median Lp(a) values of 100 (range: 82 to 115) mg/dL and 10 (range: 5 to 24) mg/dL in the high and low Lp(a) groups, respectively. At baseline, there was no difference in coronary artery disease severity or plaque burden. Patients with high Lp(a) showed accelerated progression of low-attenuation plaque compared with low Lp(a) patients (26.2 ± 88.4 mm(3) vs −0.7 ± 50.1 mm(3); P = 0.020). Multivariable linear regression analysis confirmed the relation between Lp(a) and low-attenuation plaque volume progression (β = 10.5% increase for each 50 mg/dL Lp(a), 95% CI: 0.7%-20.3%). There was no difference in total, calcific, and noncalcific plaque volume progression. CONCLUSIONS: Among patients with advanced stable coronary artery disease, Lp(a) is associated with accelerated progression of coronary low-attenuation plaque (necrotic core). This may explain the association between Lp(a) and the high residual risk of myocardial infarction, providing support for Lp(a) as a treatment target in atherosclerosis

Pulmonary Tuberculosis in Severely-malnourished or HIV-infected Children with Pneumonia: A Review

Presentation of pulmonary tuberculosis (PTB) as acute pneumonia in severely-malnourished and HIVpositive children has received very little attention, although this is very important in the management of pneumonia in children living in communities where TB is highly endemic. Our aim was to identify confirmed TB in children with acute pneumonia and HIV infection and/or severe acute malnutrition (SAM) (weight-for-length/height or weight-for-age z score <-3 of the WHO median, or presence of nutritional oedema). We conducted a literature search, using PubMed and Web of Science in April 2013 for the period from January 1974 through April 2013. We included only those studies that reported confirmed TB identified by acid fast bacilli (AFB) through smear microscopy, or by culture-positive specimens from children with acute pneumonia and SAM and/or HIV infection. The specimens were collected either from induced sputum (IS), or gastric lavage (GL), or broncho-alveolar lavage (BAL), or percutaneous lung aspirates (LA). Pneumonia was defined as the radiological evidence of lobar or patchy consolidation and/or clinical evidence of severe/ very severe pneumonia according to the WHO criteria of acute respiratory infection. A total of 17 studies met our search criteria but 6 were relevant for our review. Eleven studies were excluded as those did not assess the HIV status of the children or specify the nutritional status of the children with acute pneumonia and TB. We identified only 747 under-five children from the six relevant studies that determined a tubercular aetiology of acute pneumonia in children with SAM and/or positive HIV status. Three studies were reported from South Africa and one each from the Gambia, Ethiopia, and Thailand where 610, 90, 35, and 12 children were enrolled and 64 (10%), 23 (26%), 5 (14%), and 1 (8%) children were identified with active TB respectively, with a total of 93 (12%) children with active TB. Among 610 HIV-infected children in three studies from South Africa and 137 SAM children from other studies, 64 (10%) and 29 (21%) isolates of M. tuberculosis were identified respectively. Children from South Africa were infected with HIV without specification of their nutritional status whereas children from other countries had SAM but without indication of their HIV status. Our review of the existing data suggests that pulmonary tuberculosis may be more common than it is generally suspected in children with acute pneumonia and SAM, or HIV infection. Because of the scarcity of data, there is an urgent need to investigate PTB as one of the potential aetiologies of acute pneumonia in these children in a carefully-conducted larger study, especially outside Africa

Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

We report a high precision measurement of the transverse single spin asymmetry $A_N$ at the center of mass energy $\sqrt{s}=200$ GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The $A_N$ was measured in the four-momentum transfer squared $t$ range $0.003 \leqslant |t| \leqslant 0.035$ \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of $A_N$ and its $t$-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this $\sqrt{s}$, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

We present the measurement of non-photonic electron production at high transverse momentum ($p_T >$ 2.5 GeV/$c$) in $p$ + $p$ collisions at $\sqrt{s}$ = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons ($\frac{e^++e^-}{2}$) at 3 GeV/$c < p_T <~$10 GeV/$c$ from bottom and charm meson decays to be ${d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0}$ = 4.0$\pm0.5$({\rm stat.})$\pm1.1$({\rm syst.}) nb and ${d\sigma_{D\to e} \over dy_e}|_{y_e=0}$ = 6.2$\pm0.7$({\rm stat.})$\pm1.5$({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at $\sqrt{s_{NN}} = 200$ GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, $\eta/s$, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of $\eta/s$ that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.