Phytochemical data parallel morpho-colorimetric variation in Polygala flavescens DC

Phytochemical data, integrated with other sources of information, represent a valuable tool helping to solve different kinds of taxonomic problems in plant systematics. In the present study, a comparative investigation, in order to clarify the systematic relationships of the three subspecies currently recognized within the Italian endemic Polygala flavescens, was carried out. Preliminarily, a morphometric and colorimetric analysis, in order to test the degree of morphological distinctiveness among the taxa, was performed. Then, a phytochemical analysis based both on volatile and non-volatile compounds was obtained. Concerning the morpho-colorimetric analysis, our results confirm most of the characters as useful to discriminate the three subspecies. In addition, some volatile and non-volatile compounds are good taxonomic markers. Morpho-colorimetric variation is clearly paralleled by phytochemical results, confirming the value of this kind of data to infer relationships in plant systematics. Based on these results, we support a taxonomic treatment at subspecific level for the involved taxa. Finally, based on the most significant morphological characters, a revision of herbarium specimens allowed to redefine the distribution pattern of the three subspecies. Accordingly, the range of P. flavescens subsp. maremmana is limited to Mt. Argentario (southern Tuscany) only. A key is also reported for the identification of the three subspecies

Workshops without Walls: Broadening Access to Science around the World

The National Aeronautics and Space Administration (NASA) Astrobiology Institute (NAI) conducted two “Workshops Without Walls” during 2010 that enabled global scientific exchange—with no travel required. The second of these was on the topic “Molecular Paleontology and Resurrection: Rewinding the Tape of Life.” Scientists from diverse disciplines and locations around the world were joined through an integrated suite of collaborative technologies to exchange information on the latest developments in this area of origin of life research. Through social media outlets and popular science blogs, participation in the workshop was broadened to include educators, science writers, and members of the general public. In total, over 560 people from 31 US states and 30 other nations were registered. Among the scientific disciplines represented were geochemistry, biochemistry, molecular biology and evolution, and microbial ecology. We present this workshop as a case study in how interdisciplinary collaborative research may be fostered, with substantial public engagement, without sustaining the deleterious environmental and economic impacts of travel

Biogeography of orchids and their pollination syndromes in small Mediterranean islands

Aims Despite the research on orchid in insular conditions, few studies are focused on the spatial distribution of their reproductive syndromes across complex insular systems. By using island species-area relationships (ISAR), we explore orchid biogeography in the Central Western-Mediterranean islands. In this study, we aim to investigate variation in ISARs using orchid pollination mechanisms as proxies to establish permanent populations explaining how the c and z parameters of ISARs vary among island types and pollination strategies and defining the most influential factors in shaping orchids' distribution.LocationMediterranean Basin.TaxonOrchidaceae. MethodsChecklist of native orchids was obtained for 112 islands of Central-Western Mediterranean Basin. The Arrhenius power function (S=c center dot Az$$S=c\cdotp {A}z$$) was used to fit ISARs for the total number of orchids as well as for functional groups defined by the pollination strategies, across different island types. We used GLM to investigate the relation between pollination syndromes with area and isolation as well as elevation, island origin, taxa richness of the source area and habitat diversity.ResultsWe found that ISARs differ between continental and volcanic islands depending on isolation. The z-value was found to be higher for more specialized strategies while the c-value increases from autogamy to allogamy, supporting the role of these two parameters in understanding distributional dynamics. Distance from the mainland is a negative predictor for all the strategies except when deception is decoupled; island area is a positive predictor only for allogamic, deceptive and food deceptive strategies, while habitat diversity is a positive predictor for allogamic, rewarding and deceptive strategies. Main Conclusions Pollination syndromes contribute in explaining the distribution of orchids in insular conditions. Furthermore, we identified differences in ISARs across pollination syndromes in which the intercept increases when the pollination shifts from a generalist to a more specialized one

Pair production with electron capture in peripheral collisions of relativistic heavy ions

The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z.alpha into account. The dependence on the transverse momentum transfer is studied and the accuracy of the equivalent photon approximation is discussed as a function of the nuclear charge.Comment: 4 postscript figure

Self-Consistent Separable Rpa Approach for Skyrme Forces: Axial Nuclei

The self-consistent separable RPA (random phase approximation) method is formulated for Skyrme forces with pairing. The method is based on a general self-consistent procedure for factorization of the two-body interaction. It is relevant for various density- and current-dependent functionals. The contributions of the time-even and time-odd Skyrme terms as well as of the Coulomb and pairing terms to the residual interaction are taken self-consistently into account. Most of the expression have a transparent analytical form, which makes the method convenient for the treatment and analysis. The separable character of the residual interaction allows to avoid diagonalization of high-rank RPA matrices and thus to minimize the calculation effort. The previous studies have demonstrated high numerical accuracy and efficiency of the method for spherical nuclei. In this contribution, the method is specified for axial nuclei. We provide systematic and detailed presentation of formalism and discuss different aspects of the model.Comment: 42 page

Anatomical Characteristics Of Intrapetrous Carotid Artery : A 3d Segmentation Study On Head Ct-Scan

The intrapetrous portion of internal carotid artery (IPCA) is one of the most unexplored anatomical regions, and its three-dimensional reconstruction in living subjects is still missing. The present study aims at describing IPCA on 3D models extracted from head CT-scans. The intrapetrous carotid artery was manually segmented on head CT-scans of 100 healthy patients free from vascular and neurological pathologies (50 males and 50 females aged between 18 and 91 years). Angles of the posterior and anterior genu, diameter and length of the horizontal portion, and volume of the entire canal were calculated through VAM\uae software. Statistically significant differences according to sex and side were assessed through two-way ANOVA test (p<0.05). Correlation of each measurement with age was calculated as well. On average the angles of the posterior and anterior genu were 120.1\ub110.4\ub0 and 118.0\ub110.0\ub0 in males, 119.5\ub19.2\ub0 and 117.6\ub110.3\ub0 in females, respectively, without statistically significant differences according to sex or side (p>0.05). Average length and diameter of the horizontal part were respectively 25.5\ub12.9 mm and 5.8\ub10.8 mm in males, 24.0\ub12.3 mm and 5.3\ub10.8 mm in females. The volume of IPCA was 0.941\ub10.215 cm3 in males, and 0.752\ub10.159 cm3 in females. Length and diameter of horizontal portion, and volume of IPCA showed statistically significant differences according to sex (p<0.05). No correlation with age was found. This study first provided data concerning not only linear and angular measurements, but also volumes of IPCA, useful in planning surgical interventions of the cranial base

Transcriptome analysis of differentiating spermatogonia stimulated with kit ligand

Kit ligand (KL) is a survival factor and a mitogenic stimulus for differentiating spermatogonia. However, it is not known whether KL also plays a role in the differentiative events that lead to meiotic entry of these cells. We performed a wide genome analysis of difference in gene expression induced by treatment with KL of spermatogonia from 7-day-old mice, using gene chips spanning the whole mouse genome. The analysis revealed that the pattern of RNA expression induced by KL is compatible with the qualitative changes of the cell cycle that occur during the subsequent cell divisions in type A and B spermatogonia, i.e. the progressive lengthening of the S phase and the shortening of the G2/M transition. Moreover, KL up-regulates in differentiating spermatogonia the expression of early meiotic genes (for instance: Lhx8, Nek1, Rnf141, Xrcc3, Tpo1, Tbca, Xrcc2, Mesp1, Phf7, Rtel1), whereas it down-regulates typical spermatogonial markers (for instance: Pole, Ptgs2, Zfpm2, Egr2, Egr3, Gsk3b, Hnrpa1, Fst, Ptch2). Since KL modifies the expression of several genes known to be up-regulated or down-regulated in spermatogonia during the transition from the mitotic to the meiotic cell cycle, these results are consistent with a role of the KL/kit interaction in the induction of their meiotic differentiation