QCD×\timesQED evolution of TMDs

We consider for the first time the QED corrections to the evolution of (un)polarized quark and gluon transverse-momentum-dependent distribution and fragmentation functions (TMDs in general). By extending their operator definition to QCD$\times$QED, we provide the mixed new anomalous dimensions up to ${\cal O}(\alpha_s\alpha)$ and the pure QED ones up to ${\cal O}(\alpha^2)$. These new corrections are universal for all TMDs up to the flavor of the considered parton, i.e., the full flavor universality of TMD evolution found in pure QCD is broken in QCD$\times$QED by the presence of the electric charge. In addition, we provide the leading-order QED corrections to the matching coefficients of the unpolarized quark TMD parton distribution function onto its integrated counterparts at ${\cal O}(\alpha_s^0\alpha)$.Comment: 9 pages, 3 figures. v2: minor corrections, accepted for publication in Phys. Lett.

Generalized Universality for TMD Distribution Functions

Azimuthal asymmetries in high-energy processes, most pronounced showing up in combination with single or double (transverse) spin asymmetries, can be understood with the help of transverse momentum dependent (TMD) parton distribution and fragmentation functions. These appear in correlators containing expectation values of quark and gluon operators. TMDs allow access to new operators as compared to collinear (transverse momentum integrated) correlators. These operators include nontrivial process dependent Wilson lines breaking universality for TMDs. Making an angular decomposition in the azimuthal angle, we define a set of universal TMDs of definite rank, which appear with process dependent gluonic pole factors in a way similar to the sign of T-odd parton distribution functions in deep inelastic scattering or the Drell-Yan process. In particular, we show that for a spin 1/2 quark target there are three pretzelocity functions.Comment: 9 pages, updated references and minor corrections, to appear in the proceedings of the QCD Evolution Workshop 2012 (May 14-17, JLAB

Effects of TMD evolution and partonic flavor on e+e−e^+e^- annihilation into hadrons

We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of BES-III and BELLE experiments. We use the parameters of the transverse-momentum-dependent (TMD) fragmentation functions that were recently extracted from the semi-inclusive deep-inelastic-scattering multiplicities at low energy from HERMES. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.Comment: 33 pages, 10 composite figures, JHEP style fil

Renormalization-group anatomy of transverse-momentum dependent parton distribution functions in QCD

The ultraviolet and rapidity divergences of transverse-momentum dependent parton distribution functions with lightlike and transverse gauge links is studied, also incorporating a soft eikonal factor. We find that in the light-cone gauge with $q^-$-independent pole prescriptions extra divergences appear which amount, at one-loop, to a cusp-like anomalous dimension. We show that such contributions are absent when the Mandelstam-Leibbrandt prescription is used. In the first case, the soft factor cancels the anomalous-dimension defect, while in the second case its ultraviolet-divergent part reduces to unity.Comment: 10 pages, 3 figures; needs ws-mpla-hep.cls (supplied). Talk presented by the first author at Workshop on "Recent Advances in Perturbative QCD and Hadronic Physics", 20--25 July 2009, ECT*, Trento, Italy, in Honor of Prof. Anatoly Efremov's 75th birthda

From global to local scale: where is the best for conservation purpose?

Demographic analysis of plant populations represents an essential conservation tool allowing to identify the population trends both at global and at the local level. In this study, the population dynamics of Helianthemum caput-felis (Cistaceae) was investigated at the local level by monitoring six populations distributed in Sardinia, Balearic Islands and Ibero-Levantine coast (Alicante). Demographic data for each population were analysed by performing Integral Projection Models (IPMs). Our results showed that, although the local trend of the main basic demographic functions was similar, vital rates and demographic dynamics varied among populations indicating high variability. In fact, asymptotic growth rate in Spanish populations widely varied both between years and populations (some populations growth, decline or strongly decline), while Sardinian populations showed greater equilibrium or a slight increase. Also, the typical pattern of a long-lived species was not supported by the results at the local scale. These results indicated that different populations of the same species can present extremely different population dynamics and support the belief that, for conservation needs, local studies are more informative than global ones: the conservation status of H. caput-felis could notably vary at a small spatial scale and, accordingly, the conservation efforts must be planned at the population level and supported by local analysis

Breeding system and inbreeding depression in a translocated population of the endangered plant Dianthus morisianus (Caryophyllaceae)

Know the breeding system of endemic plants is important to design conservation strategies. Translocations are actions to improve the survival prospects of the species, but nowadays there are only a few studies that analyse their success and make a comparison between translocation and the natural populations. Dianthus morisianus is a threatened narrow endemic plant species growing on sand dunes in SW Sardinia (Italy). The objective of this study was to assess the breeding system, the presence of inbreeding depression and pollen limitation, as well as the success of the plant translocation. All these results were compared with those from the single natural population. The breeding system was tested through five pollination treatments and the reproductive success was analysed by the fruit set, seed set, seed weight, germination and mortality rate. The translocated population behaved like the natural one on fruit and seed formation. Autonomous self-pollination was lower than the other treatments regarding fruit set and seed/ovule ratio in the two studied populations. The species is self-compatible and presents partial self-fertility. The selfing rate was higher in the translocated population and the inbreeding depression presented low values for the natural population, while the translocated population presented negative values. Neither of the populations suffered pollen limitation. The species did not present reproductive problems and it is pollinator dependent. Moreover, the translocated population demonstrated high success after five years, as an increase of the population area and new recruited plants was observed; the offspring were able to flower, fruiting and reproduce. This translocation success increases the survival prospects of the species

The vascular flora of the Marine Protected Area of "Capo Carbonara" (SE-Sardinia)

This study aims at presenting an updated inventory of the vascular flora of the Capo Carbonara Marine Protected Area, including the Sites of Community Importance “Isola dei Cavoli, Serpentara, Punta Molentis e Campulongu” and partially of “Costa di Cagliari”, in Sardinia (Italy). A total of 653 taxa are reported, 84% of which are native (5% endemics) and 16% non-native (10% neophytes, 6% archaeophytes). The native component includes 406 species, 135 subspecies, two variety and one hybrid, belonging to 75 families and 313 genera. The non-native taxa are 94 species, 13 subspecies, one variety and one hybrid, belonging to 40 families and 81 genera. Life-form analysis of native species revealed a prevalence of therophytes (49%) followed by hemicryptophytes (21%), geophytes (14%) and chamaephytes (7%). Therophytes (33%) fol lowed by phanerophytes (32%) are prevalent among the non-native taxa. Biogeographically, among native species, the Mediterranean element is largely prevailing (81%), mainly consisting of Circum-Mediterranean (39%) and Euro-Mediterranean (27%) taxa, while the American ele ment (35%) prevails over the Mediterranean species (29%) among the non-native taxa. Among endemics, the Sardo-Corsican taxa are dominant (55%), followed by Sardo-Corsican-Tuscan Archipelago (14%) and Sardinian (10%) taxa

Gone with the waves: the role of sea currents as key dispersal mechanism for Mediterranean coastal and inland plant species

Thalassochory, the dispersal of propagules through marine currents, is a key long-distance dispersal (LDD) mechanism with implications for global biogeography and particularly for island colonization. The propagules of coastal plant species are generally assumed to be better adapted for sea dispersal than those of inland plants, but this hypothesis remains largely untested. We conducted experiments on four genera (Juniperus, Daucus, Ferula, and Pancratium) and compared traits among nine species with different habitats and distributions. Our results showed that Juniperus spp. and P. maritimum have strong thalassochorous potential within the Mediterranean Basin. Interestingly, we did not find a clear association on the thalassochorous potential of coastal versus inland species within all the tested genera, apart from P. maritimum compared with the endemic inland P. illyricum. These findings suggest that thalassochory may be a more common dispersal mechanism than previously assumed. The apparently weak link of dispersal syndrome with species ecology broadens the possibility of dispersal by the sea also for inland plants, although considered to be poorly salt-tolerant. Moreover, our results reveal significant differences in sea dispersal between endemic and widespread species, but do not rule out an important role of thalassochory in shaping the distribution patterns of archipelago endemic flora. The presented method is largely replicable and could be used for further studies with a larger set of species to better delineate trends of sea dispersal syndrome among species with different ecology or dispersal traits

Germination data of four Mediterranean species of coastal sand dunes

The present work gathers new germination assays of four Mediterranean species of coastal sand dunes. The studied species are: Anthemis maritima L. subsp. maritima, Crucianella maritima L., Eryngium maritimum L. and Thinopyrum junceum (L.) Á.Löve. Seeds were collected at the time of natural seed dispersal in two sites in the South of Sardinia. The germination tests were carried out at the Sardinian Germplasm Bank (BG-SAR). Our results show a high germination capability and germination rate for the tested plant species