1,223 research outputs found

    Robustness of the O(NN) universality class

    Full text link
    We calculate the critical exponents for Lorentz-violating O(NN) λϕ4\lambda\phi^{4} scalar field theories by using two independent methods. In the first situation we renormalize a massless theory by utilizing normalization conditions. An identical task is fulfilled in the second case in a massive version of the same theory, previously renormalized in the BPHZ method in four dimensions. We show that although the renormalization constants, the β\beta and anomalous dimensions acquire Lorentz-violating quantum corrections, the outcome for the critical exponents in both methods are identical and furthermore they are equal to their Lorentz-invariant counterparts. Finally we generalize the last two results for all loop levels and we provide symmetry arguments for justifying the latter

    Bursaphelenchus pinophilus Brzeski & Baujard, 1997 (Nematoda: Parasitaphelenchinae) associated with nematangia on Pityogenes bidentatus (Herbst, 1783) (Coleoptera: Scolytinae), from the Czech Republic

    Get PDF
    The occurrence of Bursaphelenchus species in the Czech Republic is poorly known, the first report of the genus being made by Kubátová et al. (2000) who reported the association of B. eremus with the hyphomycetous microfungus, Esteya vermicola, and the bark beetle, Scolytus intricatus, collected from Quercus robur, in central Bohemia. To date, four other species have been reported from the country, namely B. fungivorus (Braasch et al., 2002), B. hofmanni (see Braasch, 2001), B. mucronatus (see Braasch, 2001) and B. vallesianus (Gaar et al., 2006). More recently, a survey for Bursaphelenchus species associated with bark- and wood-boring insects in the Czech Republic identified B. pinophilus Brzeski & Baujard, 1997 from the Moravia region. Although this represents a new country record, it was also associated with nematangia on the hind wings of a new insect vector. A total of 404 bark- and wood-boring insects were collected from declining or symptomatic trees and screened for the presence of Bursaphelenchus. Bark and longhorn beetles were captured manually after debarking parts of the trunk displaying symptoms of insect attacks. Longhorn beetle larvae were also collected together with logs cut from the trunk. Logs were kept at room temperature in the laboratory until insect emergence. Each adult insect was individually dissected in water and examined for nematodes. All nematodes resembling dauer juveniles of Bursaphelenchus were collected and identified by molecular characterisation using a region of ribosomal DNA (rDNA) containing the internal transcribed spacer regions ITS1 and ITS2. ITS-RFLP analyses using five restriction enzymes (AluI, HaeIII, HinfI, MspI, RsaI) were performed to generate the species-specific profile according to Burgermeister et al. (2009). Species identification was also confirmed by morphological data after culture of the dauers on Botrytis cinerea Pers. ex Ft., growing in 5% malt extract agar. During this survey, only species belonging to the Curculionidae, subfamily Scolytinae, revealed the presence of nematodes belonging to Bursaphelenchus. Dauers of this genus were found aggregated under the elytra in nematangia formed at the root of the hind wings (Fig. 1). The dauers were identified from 12 individuals of Pityogenes bidentatus (Herbst, 1783) (Coleoptera: Scolytinae) collected under the bark of Pinus sylvestris trunks. Each insect carried ca 10-100 dauers. The ITS-RFLP patterns of the dauers so obtained confirmed the identification of B. pinophilus associated with this insect species. Bursaphelenchus pinophilus has been found mainly in Europe and has been reported from various countries such as Poland (Brzeski & Baujard, 1997), Germany (Braasch, 2001), and Portugal (Penas et al., 2007). The recent detection of this species associated with dead P. koraiensis in Korea (Han et al., 2009) expands its geographical distribution and potential importance. It has been found associated only with Pinus species, but very little is known about the insect vector. The bark beetle, Hylurgus ligniperda, was initially suggested as the insect vector by Pe-nas et al. (2006), although the nematode associated with this insect was later reclassified as B. sexdentati by morphological and molecular analysis (Penas et al., 2007). According to the literature, P. bidentatus has been cited as a vector of Ektaphelenchus sp. (Kakuliya, 1966) in Georgia, and an unidentified nematode species in Spain (Roberston et al., 2008). Interestingly, B. pinophilus was found in the nematangia formed at the root of the hind wings of P. bidentatus. Although this phenomenon is not so common in other Bursaphelenchus species, B. rufipennis has been found recently in such a structure on the hind wings of the insect Dendroctonus rufipennis (Kanzaki et al., 2008). Although other nematode species (e.g., Ektaphelenchus spp.) are frequently found associated within the same nematangia (see Kanzaki et al., 2008), in this particular case, only dauers of B. pinophilus were identified. The association between B. pinophilus and P. bidentatus represents the first report of this biological association and the association with the Scolytinae strengthens the tight and specific links between this group of Bursaphelenchus species and members of the Scolytinae (Ryss et al., 2005)

    Management Targets to Maximize Short-Term Herbage Intake Rate

    Get PDF
    Besides grazing, the animals carry a host of other essential activities to their survival, such as rumination, vigilance and idling, and these activities compete with each other in the animal’s daily time (Fonseca et al. 2012). Therefore, any management action that provides an increase in forage intake rate, with a consequent reduction in the time necessary to achieve the daily nutrient requirements, is essential for an animal product-ion success. In this study, four experiments were performed based upon the hypothesis that different sward structures, formed by distinct sward surface heights (SSH) and levels of grazing down influence the short-term herbage intake rate (STIR)

    Optimized exploitation of aquifers: application to the Querenca-Silves aquifer system

    Get PDF
    A great deal of optimization models have been developed to support aquifer planning and management with the goal of arriving at the best decisions in relation to the number and siting of infrastructures to be built and how to operate them. A mixed-integer multi-objective linear model has been taken from the literature to define the best decision for the development of the aquifer of Querenca-Silves (Portugal). It identifies efficient solutions for the location and design of pumping stations and their catchment area to supply a given number of demand centers, without disregarding the effect of groundwater management on the piezometric surface of aquifers and the many facets of groundwater management. The multi-objective model includes two objectives: (1) the minimization of aggregate water elevation height, and (2) the minimization of aggregate water transport length, weighted by the flows conveyed from the facilities to the centers. The effect of groundwater extraction on the piezometric surface of the aquifer is modelled with a response matrix method, with the establishment of maximum drawdown to prevent over-exploitation

    An update on the genera Longidorus , Paralongidorus and Xiphinema (Family Longidoridae) in Portugal

    Get PDF
    The tribe Longidorini within the subfamily Longidorinae (Longidorus spp. and Paralongidorus spp.) and the subfamily Xiphineminae (Xiphinema spp.) are two large nematode groups with about 260 and 230 known species, respectively. They are globally two important groups of ectoparasitic nematodes considered to be major pests because of their activity as vectors of important plant nepovirus, with some species included in the list of quarantine pathogenic organisms in many European countries. Knowledge of the biodiversity and occurrence of this nematode group is a prerequisite for the establishment of sound management strategies and control measures. According to data collected from the databases (such as EPPO, FSTA, and Web of Science) and published in specialised literature, a total of 15 Longidorus, 1 Paralongidorus and 40 Xiphinema species have been recorded as present in Portugal. However, the taxonomic status of some species is controversial, and thus needs to be clarified. A comprehensive review for unravelling the biodiversity and occurrence of nematode species of the genus Longidorus, Paralongidorus and Xiphinema in Portugal is herein provided. This review includes an updated checklist of species with information on the localities, host plants and geographical distribution. Additionally, maps on the species distributions of Longidorinae and Xiphineminae nematodes present in Continental Portugal and the Portuguese Macaronesian islands are provided, as well as unpublished data on authors and comments on the current taxonomic status. Finally, new insights and directions for future research on Longidoridae in Portugal are presented

    Going green and sustainable : The influence of green HR practices on the organizational rationale for sustainability

    Get PDF
    Organizations that go green need their employees to perceive that sustainability is a priority in order to increase pro-sustainability behavior. Several factors can influence how employees perceive their organization’s com- mitment to sustainability; however, no research has yet explored how green human resource management can influence that perception. This study thus examines the role of green hiring, green training, and green com- pensation, along with age and gender, in sustaining the organizational rationale for sustainability (ORS). Results from a sample of 275 Portuguese employees, analysed through the fuzzy-set qualitative comparative analysis (fsQCA), shows that perceived ORS is mainly grounded in green hiring, and to a lesser extent, in green training. Green hiring is especially important for older employees, whereas younger employees require green training. Green compensation is surprisingly irrelevant. The study is useful for researchers and practitioners who seek to understand employees’ perception about the value and priority their organizations give to sustainability.info:eu-repo/semantics/publishedVersio

    Bioactivity of Trichilia pallida Swartz (Meliaceae) derived molecules on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

    Get PDF
    A partir do extrato em diclorometano (DIC) de folhas e frutos de Trichilia pallida Swartz, objetivou-se fazer o isolamento e identificação de substâncias com atividade inseticida sobre a traça-do-tomateiro, Tuta absoluta (Meyrick). Do extrato em DIC de folhas de T. pallida foram isolados os triterpenos 24-metilenocicloarta-3β-ol (TRIT-1), 24-metilenocicloarta-3β-26-diol (TRIT-2) e cicloarta-23-eno-3β,25-diol (TRIT-3), os esteróides 24-metileno-3,22-diidroxicolesterol (EST-1), 24-metilenocolesterol (EST-2) e 24-metileno-3β,4β,22-triidroxicolesterol (EST-3), além do limonóide gedunina (LIM) obtido de frutos da planta. As substâncias foram dissolvidas em acetona e pulverizadas a 0,1% em folíolos de tomateiro infestados com lagartas recém-eclodidas. Foram avaliadas a mortalidade de lagartas aos quinto e nono dias após a infestação, duração e sobrevivência das fases de larva e pupa, peso de pupas e porcentagem de adultos deformados. TRIT-1, EST-1 e LIM foram as moléculas que apresentaram maior atividade sobre T. absoluta, alongando o desenvolvimento larval e reduzindo a sobrevivência dessa fase.Dichloromethane (DIC) leaf and fruit extracts of Trichiliapallida Swartz were obtained for the isolation and identification of molecules with insecticidal activity against the tomato leafminer, Tuta absoluta (Meyrick). DIC leaf extracts of T. pallida yielded six compounds, the triterpenes 24-methylenecycloarta-3β-ol (TRIT-1), 24-methylenecycloarta-3β-26-diol (TRIT-2) and cycloarta-23-eno-3β,25-diol (TRIT-3), the sterols 24-methylene-3,22-dihydroxycholesterol (EST-1), 24-methylenecholesterol (EST-2) and 24-methylene-3β,4β,22-trihydroxycholesterol (EST-3), while the fruit extract yielded the limonoid gedunine (LIM). These molecules were dissolved in acetone and sprayed at 0.1% on tomato leaflets infested with newly-hatched larvae. Larval mortality at day 5 and 9 after infestation, larval and pupal developmental time and survival, pupal weight and adult malformation were evaluated. TRIT-1, EST-1 and LIM were the most effective against T. absoluta due to larval development arrestment and reduced larval survivorship.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    In Vitro Screening

    Get PDF
    This research was funded by Fundação para a Ciência e a Tecnologia (FCT-MCTES), Radiation Biology and the Biophysics Doctoral Training Programme (RaBBiT, PD/00193/2012); the scholarship grant number PD/BD/142829/2018, to T.P.P. from the RaBBiT Doctoral Training Programme. Publisher Copyright: © 2023 by the authors.Photodynamic therapy is a minimally invasive procedure used in the treatment of several diseases, including some types of cancer. It is based on photosensitizer molecules, which, in the presence of oxygen and light, lead to the formation of reactive oxygen species (ROS) and consequent cell death. The selection of the photosensitizer molecule is important for the therapy efficiency; therefore, many molecules such as dyes, natural products and metallic complexes have been investigated regarding their photosensitizing potential. In this work, the phototoxic potential of the DNA-intercalating molecules—the dyes methylene blue (MB), acridine orange (AO) and gentian violet (GV); the natural products curcumin (CUR), quercetin (QT) and epigallocatechin gallate (EGCG); and the chelating compounds neocuproine (NEO), 1,10-phenanthroline (PHE) and 2,2′-bipyridyl (BIPY)—were analyzed. The cytotoxicity of these chemicals was tested in vitro in non-cancer keratinocytes (HaCaT) and squamous cell carcinoma (MET1) cell lines. A phototoxicity assay and the detection of intracellular ROS were performed in MET1 cells. Results revealed that the IC50 values of the dyes and curcumin in MET1 cells were lower than 30 µM, while the values for the natural products QT and EGCG and the chelating agents BIPY and PHE were higher than 100 µM. The IC50 of MB and AO was greatly affected by irradiation when submitted to 640 nm and 457 nm light sources, respectively. ROS detection was more evident for cells treated with AO at low concentrations. In studies with the melanoma cell line WM983b, cells were more resistant to MB and AO and presented slightly higher IC50 values, in line with the results of the phototoxicity assays. This study reveals that many molecules can act as photosensitizers, but the effect depends on the cell line and the concentration of the chemical. Finally, significant photosensitizing activity of acridine orange at low concentrations and moderate light doses was demonstrated.publishersversionpublishe
    corecore