Consistent Off-Shell Tree String Amplitudes

We give a construction of off-shell tree bosonic string amplitudes, based on the operatorial formalism of the $N$-string Vertex, with three external massless states both for open and closed strings by requiring their being projective invariant. In particular our prescription leads, in the low-energy limit, to the three-gluon amplitude in the usual covariant gauge.Comment: 12 pages. Introductory and final parts modified in order to make them more clear. Cosmetic changes in formulae (13) and (14). Some misprints correcte

Prescriptions for Off-Shell Bosonic String Amplitudes

We give, in the framework of the bosonic string theory, simple prescriptions for computing, at tree and one-loop levels, off-shell string amplitudes for open and closed string massless states. In particular we obtain a tree amplitude for three open strings that in the field theory limit coincides with the three-gluon vertex in the usual covariant gauge and two-string one-loop amplitudes satisfying the property of transversality.Comment: 11 pages, LaTeX, to appear in the proceedings of the workshop "Quantum Aspects of Gauge Theories, Supersymmetry and Unification", Corfu (Greece), 20-26 September 1998. Eq. (12) and numerical factors in eqs. (13) and (16) corrected; some minor changes and references adde

Demand or supply? An empirical exploration of the effects of climate change on the macroeconomy

Using an original panel data set for 24 OECD countries over the sample 1990–2019 and a multivariate empirical macroeconomic framework for business cycle analysis, the paper tests the combined macroeconomic effects of climate change, environmental policies and green innovation. Overall, we find evidence of significant macroeconomic effects over the business cycle: physical risks act as negative demand shocks while transition risks act as downward supply movements. The disruptive effects on the economy typical of a disorderly transition are exacerbated for low income, high emission countries with no history of environmental policy or with a high exposure to natural disasters. In general, one size does not fit all and results support the need for a (possibly country-specific) policy mix to counteract climate change with a balance between demand-pull and technology-push policies

SURVEY OF HISTORICAL GARDENS: MULTI-CAMERA PHOTOGRAMMETRY VS MOBILE LASER SCANNING

This paper presents an investigation into the characterization of historical gardens by comparing two 3D survey methodologies. In this context, approaches employing terrestrial laser scanning are considered the most accurate, while Mobile Mapping Systems (MMSs) are considered promising due to their extreme productivity. Less common is the use of close-range photogrammetry. This paper compares two approaches based on the use of a wearable MMS and the use of an in-house built photogrammetric multi-camera prototype. The comparison aims to assess the applicability of the two techniques in this field, evaluating their advantages and disadvantages in surveying a historical garden and extracting information for tree inventory, such as the DBH (Diameter at Breast Height) and canopy footprint. We compared the practicality of surveying and processing operations; and the quality and characteristics of the point clouds obtained. Both systems produced a dense representation of the terrain. The multi-camera survey resulted to be more defined due to the lower noise of the point cloud but incomplete in the definition of tree canopies. DBH of tree trunks can be extracted with both systems, except for thinner and finer diameter trunks detected by the MMS approach but not always by the multi-camera. The MMS approach proved more effective thanks to a shorter survey time required to cover an equal area and the fact that the MMS survey alone is sufficient for the geometric description of trees. In contrast, the multi-camera approach cannot avoid integration with an aerial survey for canopy reconstructio

Review about comorbidities of behavioural disorders in children and adolescents: The focus on attention-deficit/hyperactivity disorder

Disruptive behavior disorders (DBD) present high comorbidity rate mainly for opposite-defiant disorders that are frequent among children, adolescents and adults affected by with attention deficit and hyperactivity disorder (ADHD), probably as result of common temperamental risk factors such as attention, distraction, impulsivity. ADHD tend to manifest in about 50% of individuals diagnosed as disruptive behavioral disorders