On the scalar curvature of constant mean curvature hypersurfaces in space forms

In this paper we study the behavior of the scalar curvature $S$ of a complete hypersurface immersed with constant mean curvature into a Riemannian space form of constant curvature, deriving a sharp estimate for the infimum of $S$. Our results will be an application of a weak Omori-Yau maximum principle due to Pigola, Rigoli and Setti \cite{PRS}.Comment: Final version (August 2009). To appear in Journal of Mathematical Analysis and Applications. Dedicated to Professor Marcos Dajczer on the occasion of his 60th birthda

Listening to the Experts: Correctional and Community College Administrators’ Perceptions of How Collaboration Contributes to the Public Value of a Postsecondary Correctional Education Partnership

This research examined correctional and community college administrators\u27 perceptions of collaboration and the public value impact of a PSCE partnership through a systems thinking conceptual framework. Through interviews, observations, and document reviews, I determined how these perceptions aligned with the public value of a PSCE partnership. This was a basic qualitative study involving six participants from two public agencies. Findings from this study indicate that administrators recognized: Public Safety Realignment legislation contributed to the viability of a PSCE partnership in a county jail system. Public safety improvements in the county jail system promoted a jail environment to facilitate the success of a PSCE partnership. Service coordination with jail in-reach services promoted a continuum of services to enhance the PSCE partnership. An improved jail culture has contributed to the collaboration by administrators of the PSCE partnership. Improved interagency communication has contributed to a better understanding of the missions of both partners. Promoting correctional best practices has contributed to improving the collection of program data of the PSCE partnership. Recommendations for practice and for future research are provided

Relativistic quantum dynamics of scalar bosons under a full vector Coulomb interaction

The relativistic quantum dynamics of scalar bosons in the background of a full vector coupling (minimal plus nonminimal vector couplings) is explored in the context of the Duffin-Kemmer-Petiau formalism. The Coulomb phase shift is determined for a general mixing of couplings and it is shown that the space component of the nonminimal coupling is a {\it sine qua non} condition for the exact closed-form scattering amplitude. It follows that the Rutherford cross section vanishes in the absence of the time component of the minimal coupling. Bound-state solutions obtained from the poles of the partial scattering amplitude show that the time component of the minimal coupling plays an essential role. The bound-state solutions depend on the nonminimal coupling and the spectrum consists of particles or antiparticles depending on the sign of the time component of the minimal coupling without chance for pair production even in the presence of strong couplings. It is also shown that an accidental degeneracy appears for a particular mixing of couplings.Comment: 8 pages, 1 table. arXiv admin note: text overlap with arXiv:1403.603

Innovative solutions and challenges to increase the use of poly(3-hydroxybutyrate) in food packaging and disposables

[EN] Poly(3-hydroxybutyrate) (PHB) has gain in recent years a huge interest in the food packaging field due to its renewable origin from waste as well as non-food crops, high mechanical strength, medium-to-high barrier performance, and inherent biodegradability in natural environments. Despite these advantages, PHB also shows a narrow processing window and high brittleness since this homopolyester shows low thermal stability and high crystallinity, limiting its industrial application. The present review provides an updated state of the art of the most relevant aspects in terms of processing and properties of PHB materials with a particular emphasis for their use in sustainable food packaging. It also describes the most potential strategies that can be applied to improve both the processability and mechanical properties of PHB, including the melt blending with green plasticizers and flexible biodegradable polymers as well as the development of more ductile co-polyesters. Finally, the waste management of the newly developed PHB-based articles is discussed, from their potential compostability to develop more biopolymers to more economically favored alternatives such as mechanical and chemical recycling technologies.This work was funded by the Spanish Ministry of Science and Innovation (MICINN, Spain), grant PID2021-123753NA-C32 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe", by the "European Union"; Comunidad de Madrid (Spain) by CIRCULAGROPLAST, a research Project that has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid; as well as by the Generalitat Valenciana (Spain) through the BEST Program (CIBEST/2021/94). S. Torres-Giner acknowledges the Spanish Ministry of Science and Innovation (MICINN, Spain) for his Ramón y Cajal contract (RYC2019-027784-I).Garcia-Garcia, D.; Quiles-Carrillo, L.; Balart, R.; Torres-Giner, S.; Arrieta, MP. (2022). Innovative solutions and challenges to increase the use of poly(3-hydroxybutyrate) in food packaging and disposables. European Polymer Journal. 178:1-20. https://doi.org/10.1016/j.eurpolymj.2022.11150512017

Support vector machine classification of arterial volumeâ weighted arterial spin tagging images

IntroductionIn recent years, machineâ learning techniques have gained growing popularity in medical image analysis. Temporal brainâ state classification is one of the major applications of machineâ learning techniques in functional magnetic resonance imaging (fMRI) brain data. This article explores the use of support vector machine (SVM) classification technique with motorâ visual activation paradigm to perform brainâ state classification into activation and rest with an emphasis on different acquisition techniques.MethodsImages were acquired using a recently developed variant of traditional pseudocontinuous arterial spin labeling technique called arterial volumeâ weighted arterial spin tagging (AVAST). The classification scheme is also performed on images acquired using blood oxygenationâ level dependent (BOLD) and traditional perfusionâ weighted arterial spin labeling (ASL) techniques for comparison.ResultsThe AVAST technique outperforms traditional pseudocontinuous ASL, achieving classification accuracy comparable to that of BOLD contrast images.ConclusionThis study demonstrates that AVAST has superior signalâ toâ noise ratio and improved temporal resolution as compared with traditional perfusionâ weighted ASL and reduced sensitivity to scanner drift as compared with BOLD. Owing to these characteristics, AVAST lends itself as an ideal choice for dynamic fMRI and realâ time neurofeedback experiments with sustained activation periods.In this article, we test the performance of our recently introduced method for dynamic arterial blood volume imaging (AVAST) in the context of functional MRI data classification. AVAST is compared with blood oxygenationâ level dependent (BOLD) and arterial spin labeling (ASL) perfusion data collected during a simple motor task using a support vector machine algorithm to classify the brain state. Findings suggest that the AVAST technique has similar performance as BOLD imaging, while preserving the statistical benefits of ASL techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135476/1/brb3549_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135476/2/brb3549.pd

Estudio histomorfométrico del hueso diafísario en la rata

Se ha realizado un estudio histomorfométrico de la diálisis femoral en la rata blanca cepa «Wistar» calculando las dimensiones del endostio y periostio, así como las modificaciones de las áreas de la corteza, cavidad medular y hueso total en relación a la actividad endóstica y perióstica del hueso durante el primer año de vida. Los resultados demuestran un crecimiento discontinuo con una fase de enlentecimiento entre los 25 y 45 días de vida. La evolución de los cambios diafisarios en la rata es superponible a la del hombre, considerándola un animal de experimentación válido para estudiar los fenómenos de remodelación ósea durante el crecimiento.A histomophometric study of the femoral diaphyseal bone was undertaken in «Wistar» albine rat. Measurements of the endosteal and periosteal thickness as weel as variations in cortical, medular and total bone areas in relation to the endosteal and periosteal bone activity during the first year of life were analyzed. The results showed a continuous growth increase with a phase of lower growth rate from the 25th to the 45th day of life. The pattern of diaphyseal growing changes resembled that found in humans. The rat can therefore be considered as a suitable experimental animal for the study of bone remodeling during growth