1,245 research outputs found
Robustness of the O() universality class
We calculate the critical exponents for Lorentz-violating O()
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
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
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)
Enabling Seamless Data Security, Consensus, and Trading in Vehicular Networks
Cooperative driving is an emerging paradigm to enhance the safety and
efficiency of autonomous vehicles. To ensure successful cooperation, road users
must reach a consensus for making collective decisions, while recording
vehicular data to analyze and address failures related to such agreements. This
data has the potential to provide valuable insights into various vehicular
events, while also potentially improving accountability measures. Furthermore,
vehicles may benefit from the ability to negotiate and trade services among
themselves, adding value to the cooperative driving framework. However, the
majority of proposed systems aiming to ensure data security, consensus, or
service trading, lack efficient and thoroughly validated mechanisms that
consider the distinctive characteristics of vehicular networks. These
limitations are amplified by a dependency on the centralized support provided
by the infrastructure. Furthermore, corresponding mechanisms must diligently
address security concerns, especially regarding potential malicious or
misbehaving nodes, while also considering inherent constraints of the wireless
medium. We introduce the Verifiable Event Extension (VEE), an applicational
extension designed for Intelligent Transportation System (ITS) messages. The
VEE operates seamlessly with any existing standardized vehicular communications
protocol, addressing crucial aspects of data security, consensus, and trading
with minimal overhead. To achieve this, we employ blockchain techniques,
Byzantine fault tolerance (BFT) consensus protocols, and cryptocurrency-based
mechanics. To assess our proposal's feasibility and lightweight nature, we
employed a hardware-in-the-loop setup for analysis. Experimental results
demonstrate the viability and efficiency of the VEE extension in overcoming the
challenges posed by the distributed and opportunistic nature of wireless
vehicular communications
Optimized exploitation of aquifers: application to the Querenca-Silves aquifer system
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
Management Targets to Maximize Short-Term Herbage Intake Rate
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)
An update on the genera Longidorus , Paralongidorus and Xiphinema (Family Longidoridae) in Portugal
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
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)
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
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