Transverse Takahashi Identities and Their Implications for Gauge Independent Dynamical Chiral Symmetry Breaking

In this article, we employ transverse Takahashi identities to impose valuable non-perturbative constraints on the transverse part of the fermion-photon vertex in terms of new form factors, the so called $Y_i$ functions. We show that the implementation of these identities is crucial in ensuring the correct local gauge transformation of the fermion propagator and its multiplicative renormalizability. Our construction incorporates the correct symmetry properties of the $Y_i$ under charge conjugation operation as well as their well-known one-loop expansion in the asymptotic configuration of incoming and outgoing momenta. Furthermore, we make an explicit analysis of various existing constructions of this vertex against the demands of transverse Takahashi identities and the previously established key features of quantum electrodynamics, such as gauge invariance of the critical coupling above which chiral symmetry is dynamically broken. We construct a simple example in its quenched version and compute the mass function as we vary the coupling strength and also calculate the corresponding anomalous dimensions $\gamma_m$. There is an excellent fit to the Miransky scalling law and we find $\gamma_m=1$ rather naturally in accordance with some earlier results in literature, using arguments based on Cornwall-Jackiw-Tomboulis effective potential technique. Moreover, we numerically confirm the gauge invariance of this critical coupling.Comment: 16 pages, 4 figure

Establishment of economic thresholds for olive moth, Prays oleae (Bern.) in Tras-os-Montes region

A mathematical model is presented which aims to establish the economic thresholds for the flower generation of olive moth, Prays oleae (Bern.) in Tràs-os- Montes (north-eastern Portugal). The model is based on observations taken between 1993 and 1998, on olives of the oil variety Cobrançosa, grown under rain-fed conditions and without pesticide treatments for several years. It takes into account factors such as cost and efficacy of spraying, environmental impact, expected yield, price and crop losses. According to this model the control of the pest is justified when the percent of flower infestation is between 4.0 % and 6.0 % during the years of intermediate and high expected yields, (i.e., about 2400 kg/ha) and between 8.0 % and 11.0 % in the years of lower expected yields (i.e. approximately 1000 kg/ha) for prices usually practised in the region

Screening of pair fluctuations in superconductors with coupled shallow and deep bands: a route to higher temperature superconductivity

A combination of strong Cooper pairing and weak superconducting fluctuations is crucial to achieve and stabilize high-Tc superconductivity. We demonstrate that a coexistence of a shallow carrier band with strong pairing and a deep band with weak pairing, together with the Josephson-like pair transfer between the bands to couple the two condensates, realizes an optimal multicomponent superconductivity regime: it preserves strong pairing to generate large gaps and a very high critical temperature but screens the detrimental superconducting fluctuations, thereby suppressing the pseudogap state. Surprisingly, we find that the screening is very efficient even when the inter-band coupling is very small. Thus, a multi-band superconductor with a coherent mixture of condensates in the BCS regime (deep band) and in the BCS-BEC crossover regime (shallow band) offers a promising route to higher critical temperatures.Comment: 8 pages, 1 figure, including supplemental material

Pseudoscalar mesons: Light front wave functions, GPDs, and PDFs

We develop a unified algebraic model which satisfactorily describes the internal structure of pion and kaon as well as heavy quarkonia (ηc and ηb). For each of these mesons, we compute their generalized parton distributions (GPDs), built through the overlap representation of their light front wave function, tightly constrained by the modern and precise knowledge of their quark distribution amplitudes. From this threedimensional knowledge of mesons, we deduce parton distribution functions (PDFs) as well as electromagnetic form factors and construct the impact parameter space GPDs. The PDFs for mesons formed with light quarks are then evolved from the hadronic scale of around 0.3 to 5.2 GeV, probed in experiments. We make explicit comparisons with experimental results available and with earlier theoretical predictions.FAPESP Postdoctoral Fellowship Grant No. 2018/17643-5CONACyTCIC of UMSNH for the Research Grant No. 4.10

Protecção contra a traça da oliveira, Prays oleae Bern. em olivicultura biológica.

Com uma área correspondente a mais de 30% da área certificada em agricultura biológica em Portugal, o olival e também, no país, uma das culturas com maior potencial de crescimento segundo este modo de produção. Tal potencial só poderá no entanto, concretizar-se desde que sejam dispensados a cultura as cuidados adequados, nomeadamente ao nível da protecção contra pragas e doenças, como forma de garantir uma produção rentável, num mercado cada vez mais competitivo. Entre as pragas da oliveira que deverão ser alvo de medidas de protecção, destaca-se, pela gravidade dos prejuízos que pode ocasionar, a traça-da-oliveira, Prays aleae (Bern.), espécie que, desenvolvendo três gerações anuais, ataca sucessivamente, folhas, flores e frutos. Na presente comunicação analisam-se as principais estratégias de protecção disponíveis contra esta praga em olivicultura biológica, assim como os progressos em curso no sentido do desenvolvimento de novas estratégias. Refere-se, por um lado, a importância da valorização da acção da fauna auxiliar indígena e da luta microbiológica por meio de Bacillus turingiensis (Berliner). Par outro lado analisam-se as possibilidades do tratamento biológico com tricogramas e crisópideos, assim como da luta por confusão sexual

Generalizing the DGLAP Evolution of Fragmentation Functions to the Smallest x Values

An approach which unifies the Double Logarithmic Approximation at small x and the leading order DGLAP evolution of fragmentation functions at large x is presented. This approach reproduces exactly the Modified Leading Logarithm Approximation, but is more complete due to the degrees of freedom given to the quark sector and the inclusion of the fixed order terms. We find that data from the largest x values to the peak region can be better fitted than with other approaches.Comment: 10 pages, 3 figure

Protecção contra a mosca da azeitona, Bactrocera oleae (Gmel.) em olivicultura biológica: situação actual e perspectivas.

O interesse crescente da parte, quer de produtores quer de consumidores, pela agricultura biológica, a par da grande importância económica e social que a oliveira tem em Portugal, justificam a prioridade que deverá ser atribuída, no País, ao desenvolvimento da olivicultura biológica. Assim, a prática deste modo de produção poderá contribuir decisivamente para um melhor equilíbrio entre a oferta e a procura do azeite respeitando, ao mesmo tempo, exigências de protecção ambiental e de preservação do espaço rural. No entanto, a olivicultura biológica só terá futuro se concretizada através de práticas agrícolas adequadas, nomeadamente no domínio da protecção contra pragas e doenças. Nesta óptica deverá ser dedicada especial atenção à mosca-da-azeitona, Bactrocera oleae (Gmel.), a mais disseminada e melhor conhecida praga da oliveira, pela gravidade dos prejuízos directos e indirectos que pode ocasionar. Face ao exposto, na presente comunicação analisam-se as possibilidades actuais e os progressos registados no âmbito da protecção contra esta importante praga, em olivicultura biológica. Referem-se quer as medidas indirectas, como a escolha de cultivares, o fomento e protecção da fauna auxiliar indígena e a antecipação da colheita, quer os meios directos, como os biológicos, culturais, biotécnicos e químicos com pesticidas autorizados

Ecosystem indicators for measuring industrial symbiosis

Industrial symbiosis (IS) is a collaborative approach among firms involving physical exchanges of materials, energy, and wastes, which creates economic advantages for firms and environmental benefits for the society. In this paper, we adopt an ecosystem approach to conceptualize the network of firms involved in IS relationships (ISN), in terms of organisms (firms), functions (waste exchange), and services (environmental benefits), and provide new insight on how to assess and compute IS performance indicators. In particular, we designed five classes of indicators aimed at assessing 1) the impact of services provided by ISNs on the environment, 2) the performance of the ISN services, 3) how the single functions contribute to ISN services, 4) the performance of the ISN functions, and 5) how the single firms contribute to ISN functions. A numerical example is also discussed showing how to compute them and the information they provide. The proposed indicators are useful to develop proper strategies to increase the efficiency of the system in exploiting the IS synergies, to improve the symbiotic exchanges carried out in ISNs, and to identify firms contributing most to IS benefits. Hence, they may assist managers of ISNs and policymakers in decision-making aspects, an urgent need of the literature