Diffraction and an infrared finite gluon propagator

We discuss some phenomenological applications of an infrared finite gluon propagator characterized by a dynamically generated gluon mass. In particular we compute the effect of the dynamical gluon mass on $pp$ and ${\bar{p}}p$ diffractive scattering. We also show how the data on $\gamma p$ photoproduction and hadronic $\gamma \gamma$ reactions can be derived from the $pp$ and $\bar{p}p$ forward scattering amplitudes by assuming vector meson dominance and the additive quark model.Comment: 4 pages, 7 figures, added references and figures, changed structure. Contribution to Proceedings of XVIIIth Reuniao de Trabalho sobre Interacoes Hadronicas, Sao Paulo, Brazil, 22-24 May, 200

Control as an approach to preventing burnout among health care personnel

The burnout syndrome may be understood as a result of sustained physiological activation upcoming from occupational stress, together with the failure of the subject to cope with job situation—at stimulus level or on consequent reaction. Under this model, one can put forward two main conditions to prevent burnout through emotional regulation: (1) awareness of the uneasiness on the part of the subject enabling him to (2) act over those demands. The aim of the present study was to gain additional information about the relationship between burnout and control. With a mean age of 33.6 years (S.D.=9.06), subjects were 273 oncology nurses (33 men and 240 women) with direct care responsibilities. All subjects completed the Portuguese adaptations of the Maslach Burnout Inventory, to assess the burnout syndrome, and the Working Conditions and Control Questionnaire, which elicits six job control aspects. The correlations between MBI and control show that individuals who reported greater control feel more personal accomplishment, decreased emotional exhaustion, and display less depersonalization. Moreover, prediction of burnout through regression analysis shows that it is highly dependent of all control variables. These findings are consistent with the hypothesis that burnout is mostly due to the lack of control over stressful work conditions.info:eu-repo/semantics/publishedVersio

Variation, Systematics, and Relationships of the \u3cem\u3eLeptodactylus Bolivianus\u3c/em\u3eComplex (Amphibia: Anura: Leptodactylidae)

A cluster of morphologically similar frogs of the genus Leptodactylus having a pair of distinct dorsolateral folds on the dorsum and well-developed lateral fringes on the toes has never been systematically evaluated by examining materials from throughout its geographic range. The species involved are herein referred to as members of the Leptodactylus bolivianus complex. There have been three names proposed for members of this complex: Leptodactylus bolivianus Boulenger, 1898; Leptodactylus insularum Barbour, 1906; and Leptodactylus romani Melin, 1941. The collective range for the L. bolivianus complex is from Costa Rica southward through Panama, extending across northern South America (east of the Andes) in the river valleys draining to the Caribbean, and throughout much of the Amazon basin with southernmost limits in the Bolivian departments of La Paz, Cochabamba, and Santa Cruz. We analyze variation in this complex of frogs throughout its geographic range to understand inherent patterns of differentiation and to interpret those patterns in terms of species-level recognition, distributions, and relationships

Are \u3cem\u3eLeptodactylus didymus\u3c/em\u3e and \u3cem\u3eL. mystaceus\u3c/em\u3e Phylogenetically Sibling Species (Amphibia, Anura, Leptodactylidae)?

The Leptodactylus fuscus species group consists of 25 currently recognized species; within this species group and distributed throughout the Amazon Basin, Atlantic Forests, Gran Chaco, and cerrados is the L. mystaceus species complex. This species complex consists of L. didymus, L. elenae, L. mystaceus, L. notoaktites, and L. spixi. Adult morphologies have been used to distinguish these species from each other except for L. didymus and L. mystaceus (Heyer, 1978; Heyer et al., 1996). Leptodactylus didymus and L. mystaceus are morphologically indistinguishable; the species are recognizable only by the characteristics of their advertisement calls: non-pulsed in L. didymus and pulsed in L. mystaceus (Heyer et al., 1996). Traditionally, L. mystaceus and L. didymus have been considered sibling species. The concept of sibling species was originally introduced by Mayr (1942: 151) to describe pairs or groups of morphologically identical or nearly identical species; however, in subsequent work Mayr (1976) interchangeably used the terms sibling and cryptic species to describe morphologically similar species. Mayr (1942: 151) considered sibling species to be important in understanding the full complexity of animal speciation. In order to differentiate these two terms, herein we take a narrow cladistic methodological approach (i.e., dichotomous speciation) by which we restrict the term sibling species to two taxa that share a most recent common ancestor; whereas, the term cryptic (derived from the Greek Kruptos, meaning \u27hidden\u27; Allaby, 1991) species refers to hidden diversity and does not necessarily imply close phylogenetic relationship. Thus, the sibling species pair of L. didymus and L. mystaceus assumes two postulates: (1) the taxa shared a most recent common ancestor not shared with other species in the L. mystaceus species complex and (2) the two taxa could represent a recent speciation event (i.e., not enough time has passed to reach morphological differentiation, although this is not a requisite). Herein, we analyze the genetic diversity among taxa in this species complex to determine if the sibling species L. didymus and L. mystaceus are sister taxa. If the assumptions about sibling species are correct, then we would expect that the two taxa involved would be genetically closer between themselves than with any other closely related species

ARE Leptodactylus didymus AND L. mystaceus PHYLOGENETICALLY SIBLING SPECIES (AMPHIBIA, ANURA, LEPTODACTYLIDAE)?

The Leptodactylus fuscus species group consists of 25 currently recognized species; within this species group and distributed throughout the Amazon Basin, Atlantic Forests, Gran Chaco, and cerrados is the L. mystaceus species complex. This species complex consists of L. didymus, L. elenae, L. mystaceus, L. notoaktites, and L. spixi. Adult morphologies have been used to distinguish these species from each other except for L. didymus and L. mystaceus (Heyer, 1978; Heyer et al., 1996). Leptodactylus didymus and L. mystaceus are morphologically indistinguishable; the species are recognizable only by the characteristics of their advertisement calls: non-pulsed in L. didymus and pulsed in L. mystaceus (Heyer et al., 1996). Traditionally, L. mystaceus and L. didymus have been considered sibling species. The concept of sibling species was originally introduced by Mayr (1942: 151) to describe pairs or groups of morphologically identical or nearly identical species; however, in subsequent work Mayr (1976) interchangeably used the terms sibling and cryptic species to describe morphologically similar species. Mayr (1942: 151) considered sibling species to be important in understanding the full complexity of animal speciation. In order to differentiate these two terms, herein we take a narrow cladistic methodological approach (i.e., dichotomous speciation) by which we restrict the term sibling species to two taxa that share a most recent common ancestor; whereas, the term cryptic (derived from the Greek Kruptos, meaning \u27hidden\u27; Allaby, 1991) species refers to hidden diversity and does not necessarily imply close phylogenetic relationship. Thus, the sibling species pair of L. didymus and L. mystaceus assumes two postulates: (1) the taxa shared a most recent common ancestor not shared with other species in the L. mystaceus species complex and (2) the two taxa could represent a recent speciation event (i.e., not enough time has passed to reach morphological differentiation, although this is not a requisite). Herein, we analyze the genetic diversity among taxa in this species complex to determine if the sibling species L. didymus and L. mystaceus are sister taxa. If the assumptions about sibling species are correct, then we would expect that the two taxa involved would be genetically closer between themselves than with any other closely related species

\u3cem\u3eLeptodactylus silvanimbus\u3c/em\u3e

Adult Leptodactylus silvanimhus are of moderate sized, the head is about as wide as long, and the hind limbs are moderate in length (see Table; also see Heyer and Thompson 2000 for definitions of adult size and leg length categories for Leptodacrylus). The male vocal sac is single and internal. Male forearms are hypertrophied in larger individuals. Adult males have two black thumb spines on each hand and lack chest spines. Individuals lack dorsolateral folds. The toe tips are narrow, not expanded. Females have weakly developed lateral toe fringes and males either have lateral toe ridges or weakly developed fringes. The upper shank surface is shagreened with several dark coni apicales. The outer tarsus has white-tipped tubercles and small dark coni apicales. The sole of the foot is mostly smooth with a few tiny dark coni apicales. The upper lip is gray, paler below and behind the eye. The dorsal pattern is grayish-brown with slightly darker interorbital and middorsal blotches. The species lacks light middorsal stripes. The belly pattern is almost uniform cream. The posterior thigh surfaces are mottled; no individuals have distinct light horizontal stripes on the lower portion of the posterior thigh. The dorsal shank surfaces have irregular dark crossbands

On the Engimatic Distribution of The Honduran Endemic \u3cem\u3eLeptodactylus Silvanimbus\u3c/em\u3e (Amphibia: Anura: Leptodactylidae)

Most species of the frog genus Leptodactylus occur in South America, and all authors who have treated the zoogeography of the genus have concluded that it originated somewhere in South America (e.g., Savage 1982). Savage (1982, 518) summarized the historical herpetofaunal units of the Neotropics as follows: All evidence points to an ancient contiguity and essential similarity of a generalized tropical herpetofauna that ranged over tropical North, Middle, and most of South America in Cretaceous-Paleocene times. Descendents of this fauna are represented today by the South and Middle American tracks (Elements). To the north of this fauna ranged a subtropical-temperate Laurasian derived unit, today represented by the Old Northern Element (track). By Eocene, northern and southern fragments of the generalized tropical units had become isolated in Middle and South America, respectively. Differentiation in situ until Pliocene produced the distinctive herpetofaunas that became intermixed with the establishment of the Isthmian Link

Genetic Resolution of the Enigmatic Lesser Antillean Distribution of the Frog \u3cem\u3eLeptodactylus Validus\u3c/em\u3e (Anura, Leptodactylidae)

Leptodactylus validus has an unusual distribution, inhabiting Trinidad, Tobago, and the Lesser Antilles, but not the mainland of South America. This distribution is inconsistent with other distribution patterns observed for these islands. Although slight variation in adult morphology has been observed among the different island populations of L. validus, call data suggest the presence of a single species. Calls of L. pallidirostris from Venezuela and Brazil suggested that this taxon might be conspecific with L. validus. Sequence data from the 12S and 16S mt rDNA genes indicate that L. validus represents a single species throughout its distribution and is conspecific with L. pallidirostris. Dispersal of L. validus from Trinidad and Tobago to the Lesser Antilles was likely mediated by human activities