T-Dualities and Doubled Geometry of the Principal Chiral Model

The Principal Chiral Model (PCM) defined on the group manifold of SU(2) is here investigated with the aim of getting a further deepening of its relation with Generalized and Doubled Geometry. A one-parameter family of equivalent Hamiltonian descriptions is introduced, and cast into the form of Born geometries. Then O(3,3) duality transformations of the target phase space are performed and we show that the resulting dual models are defined on the group SB(2,C) which is the Poisson-Lie dual of SU(2) in the Iwasawa decomposition of the Drinfel'd double SL(2, C). Moreover, starting from the Lagrangian approach, a new kind of duality is found between the SU(2) PCM and the natural one defined on SB(2,C) which is not an isometry of the target phase space. A parent action with doubled degrees of freedom and configuration space SL(2, C) is then defined that reduces to either one of the dually related models, once suitable constraints are implemented.Comment: 41 pages, revised version published in JHE

The Elicitation of Descriptive and Procedural Discourse in Expressive Aphasia

Currently, there are no clear clinical guidelines for determining the method that will elicit the best discourse sample from individuals with expressive aphasia. Additionally, there is no universal method used to evaluate discourse samples. Archival data was collected from a 42-year old male who experienced a cerebrovascular accident 15 years ago and was then diagnosed with expressive aphasia. Two consecutive 8-week courses of treatment periods were analyzed to determine the best discourse elicitation and evaluation method. A comparison of descriptive and procedural discourse elicitation techniques revealed that procedural discourse results in a higher average percent Correct Information Units (%CIUs), words per minute (WPM), and Type-Token Ratio (TTR). Additionally, the results suggested that evaluating discourse using a combined analysis approach, both microlinguistic and macrolinguistic analyses, revealed more clinically relevant information. Though this study does need to be replicated with a larger population, this analysis may lead to more informed discussions when selecting a discourse elicitation and evaluation technique for treatment

NK cells on the ViP stage of COVID-19

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Distance measures in gravitational-wave astrophysics and cosmology

We present quantities which characterize the sensitivity of gravitational-wave observatories to sources at cosmological distances. In particular, we introduce and generalize the horizon, range, response, and reach distances. These quantities incorporate a number of important effects, including cosmologically well-defined distances and volumes, cosmological redshift, cosmological time dilation, and rate density evolution. In addition, these quantities incorporate unique aspects of gravitational wave detectors, such as the variable sky sensitivity of the detectors and the scaling of the sensitivity with inverse distance. An online calculator (https://users.rcc.uchicago.edu/~dholz/gwc/) and python notebook (https://github.com/hsinyuc/distancetool) to determine GW distances are available. We provide answers to the question: "How far can gravitational-wave detectors hear?

Livable neighborhoods for sustainable cities: Insights from Barcelona

The paper proposes a reflection on the superblock model - or supermanzana, in its well-known Spanish application - in the context of the debate on the 15-minute city and on the functional reorganization of mobility and public space to improve the quality of life, health and accessibility in urban areas. The impacts of car traffic on the livability of cities and neighborhoods, in terms of safety, air pollution, noise, but also in terms of consumption and quality of public space, are widely acknowledged. These issues are not new to the debate: since the first decades of the 20th century, with the advent and rapid diffusion of the automobile, concerns on the impacts of vehicular traffic and issues of urban livability and traffic separation have been raised by urban and transport planners. As a consequence, various models of neighborhood planning emerged, proposing solutions to limit these impacts. The supermanzana model takes up the principles of neighborhood planning by identifying a main road network and setting up a system of superblocks within the meshes of this network, in order to improve accessibility, equity, health and livability; it aims on the one hand to transform public spaces at the neighborhood level and on the other hand to reorganize the existing urban structure. The application of the supermanzana model in Barcelona offers an interesting contribution to the debate on the 15-minute city, showing how the principle of traffic separation can be applied to existing, dense urban contexts, reclaiming public space to more livable neighborhoods and sustainable cities. The analysis of the case study of Barcelona can contribute to research and policy, learning from this experience and especially from the critical issues that emerged

Photo-Protective Mechanisms and the Role of Poly (ADP-Ribose) Polymerase Activity in a Facultative CAM Plant Exposed to Long-Term Water Deprivation

The Crassulacean acid metabolism (CAM) pathway helps plants to alleviate the oxidative stress under drought, but the shift to CAM-idling may expose plants to the overproduction of reactive oxygen species causing cell damages. The facultative CAM species Portulacaria afra L., was subjected to long-term water deprivation to assess the photo-protective strategies and the poly (ADP-ribose) polymerase (PARP) activity during water stress and plant capability to recover from the stress. Measurements of titratable acidity, chlorophyll fluorescence emission, and antioxidant activity were performed during the stress and rewatering. Under water deprivation, plants shifted from C3 to CAM metabolism, reaching the CAM-idling status at the end of the stress period. The daily variation of the titratable acidity and PARP activity increased at the beginning of stress and declined with stress progression, reaching the lowest value at the end of stress treatment. H2 O2 content, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities increased with the severity of water stress. The photochemical processes remained high during the entire stress period indicating the presence of alternative sinks to CO2 fixation. The elevated activity of catalase under severe water stress suggests the occurrence of photorespiration in sustaining the photosynthetic electron transport under CAM-idling condition. The overall data indicate that scavenger enzymes, photorespiration and PARP activity modulation contribute to the strong resistance of P. afra to severe water stress, preserving the functioning of photosynthetic apparatus and ensuring plant recovery with rewatering

A low-luminosity type-1 QSO sample; III. Optical spectroscopic properties and activity classification

We report on the optical spectroscopic analysis of a sample of 99 low-luminosity quasi-stellar objects (LLQSOs) at $z\leq 0.06$ base the Hamburg/ESO QSO survey (HES). The LLQSOs presented here offer the possibility of studying the faint end of the QSO population at smaller cosmological distances and, therefore, in greater detail. A small number of our LLQSO present no broad component. Two sources show double broad components, whereas six comply with the classic NLS1 requirements. As expected in NLR of broad line AGNs, the [S{\sc{ii}}]$-$based electron density values range between 100 and 1000 N$_{e}$/cm$^{3}$. Using the optical characteristics of Populations A and B, we find that 50\% of our sources with H$\beta$ broad emission are consistent with the radio-quiet sources definition. The remaining sources could be interpreted as low-luminosity radio-loud quasar. The BPT-based classification renders an AGN/Seyfert activity between 50 to 60\%. For the remaining sources, the possible star burst contribution might control the LINER and HII classification. Finally, we discuss the aperture effect as responsible for the differences found between data sets, although variability in the BLR could play a significant role as well.Comment: 22 pages; 5 tables; 17 figures; in press with A&