Estimating the Prompt Electromagnetic Luminosity of a Black Hole Merger

Although recent work in numerical relativity has made tremendous strides in quantifying the gravitational wave luminosity of black hole mergers, very little is known about the electromagnetic luminosity that might occur in immediate conjunction with these events. We show that whenever the heat deposited in the gas near a pair of merging black holes is proportional to its total mass, and the surface density of the gas in the immediate vicinity is greater than the (quite small) amount necessary to make it optically thick, the characteristic scale of the luminosity emitted in direct association with the merger is the Eddington luminosity independent of the gas mass. The duration of the photon signal is proportional to the gas mass, and is generally rather longer than the merger event. At somewhat larger distances, dissipation associated with realigning the gas orbits to the new spin orientation of the black hole can supplement dissipation of the energy gained from orbital adjustment to the mass lost in gravitational radiation; these two heat sources can combine to augment the electromagnetic radiation over longer timescales.Comment: 14 pages. Ap J, in pres

PAALF People\u27s Plan: East Portland Pilot

Recognizing the traumatic experience of being forced to move and losing community, this plan reflects the hopes of community members who seek to rebuild their lives in a new place. The East Portland Pilot Plan applies the urban planning practice of placemaking as a transformative intervention for addressing challenges and stabilizing the Black community in East Portland. This plan also emerges at a critical time, as existing city plans for East Portland indicate significant future public investment and development. This plan has been written with a wide audience in mind. The material is relevant to homeowners, community activists, urban planners, nonprofit advocates and policymakers among others. The East Portland Pilot Plan is on the one hand a portrait of the Black community in East Portland; a portrait that has been narrated largely by the people themselves, and recorded in this document. On the other hand, the EPPP is a guide to action, a toolkit to address some of the most persistent issues facing Africans and African Americans and a roadmap to a thriving and vibrant Black community in East Portland. This project was conducted under the supervision of Sy Adler, Susan Hartnett and Marisa Zapata

Microscopic theory of network glasses

A molecular theory of the glass transition of network forming liquids is developed using a combination of self-consistent phonon and liquid state approaches. Both the dynamical transition and the entropy crisis characteristic of random first order transitions are mapped out as a function of the degree of bonding and the density. Using a scaling relation for a soft-core model to crudely translate the densities into temperatures, the theory predicts that the ratio of the dynamical transition temperature to the laboratory transition temperature rises as the degree of bonding increases, while the Kauzmann temperature falls relative to the laboratory transition. These results indicate why highly coordinated liquids should be "strong" while van der Waals liquids without coordination are "fragile".Comment: slightly revised version that has been accepted for publication in Phys. Rev. Let

Structural dynamics effects on the ultrafast chemical bond cleavage of a photodissociation reaction

The correlation between chemical structure and dynamics has been explored in a series of molecules with increasing structural complexity in order to investigate its influence on bond cleavage reaction times in a photodissociation event. Femtosecond time-resolved velocity map imaging spectroscopy reveals specificity of the ultrafast carbon–iodine (C–I) bond breakage for a series of linear (unbranched) and branched alkyl iodides, due to the interplay between the pure reaction coordinate and the rest of the degrees of freedom associated with the molecular structure details. Full-dimension time-resolved dynamics calculations support the experimental evidence and provide insight into the structure–dynamics relationship to understand structural control on time-resolved reactivity

The Histone Chaperones SET/TAF-1β and NPM1 Exhibit Conserved Functionality in Nucleosome Remodeling and Histone Eviction in a Cytochrome c-Dependent Manner

Chromatin homeostasis mediates essential processes in eukaryotes, where histone chaperones have emerged as major regulatory factors during DNA replication, repair, and transcription. The dynamic nature of these processes, however, has severely impeded their characterization at the molecular level. Here, fluorescence optical tweezers are applied to follow histone chaperone dynamics in real time. The molecular action of SET/template-activating factor-Iβ and nucleophosmin 1—representing the two most common histone chaperone folds—are examined using both nucleosomes and isolated histones. It is shown that these chaperones present binding specificity for fully dismantled nucleosomes and are able to recognize and disrupt non-native histone-DNA interactions. Furthermore, the histone eviction process and its modulation by cytochrome c are scrutinized. This approach shows that despite the different structures of these chaperones, they present conserved modes of action mediating nucleosome remodeling.Ministerio de Educación y Cultura FPU016/01513European Commission PAIDI-DOCTOR 2020 DOC_00796European Molecular Biology Organization 8541European ARBRE-Mobieu consortium CA15126Ministerio de Ciencia e Innovación PGC 2018-096049-BI00, PID2021-126663NB-100Junta de Andalucía BIO198, US-1254317, P18-FR-3487, P18HO-409

Acoso en el ambiente escolar : análisis de un cuestionario mediante Teoría de Respuesta al Ítem y Análisis de Correspondencias Múltiples

Universitas Psychologica, vol. 13, no. 2, pp 443-456En este estudio se reanalizaron los datos de Cepeda, Pacheco, García y Piraquive (2008) mediante un modelo de teoría de respuesta al ítem, y mediante análisis de correspondencias múltiples y de clasificación. Se encontró que las propiedades psicométricas del cuestionario de acoso escolar son bastante buenas (α = 0.96 y buen ajuste al modelo unidimensional a partir del análisis paralelo). Además, se presentan las coincidencias entre los resultados de los dos tipos de análisis, y se encuentran resultados similares a otros estudios en el país. Los resultados de este estudio indican que el cuestionario analizado es una medida válida y confiable del acoso en el contexto escolar

Human embryonic stem cells passaged using enzymatic methods retain a normal karyotype and express CD30

Human embryonic stem cells (hESCs) are thought to be susceptible to chromosomal rearrangements as a consequence of single cell dissociation. Compared in this study are two methods of dissociation that do not generate single cell suspensions (collagenase and EDTA) with an enzymatic procedure using trypsin combined with the calcium-specific chelator EGTA (TEG), that does generate a single cell suspension, over 10 passages. Cells passaged by single cell dissociation using TEG retained a normal karyotype. However, cells passaged using EDTA, without trypsin, acquired an isochromosome p7 in three replicates of one experiment. In all of the TEG, collagenase and EDTA-treated cultures, cells retained consistent telomere length and potentiality, demonstrating that single cell dissociation can be used to maintain karyotypically and phenotypically normal hESCs. However, competitive genomic hybridization revealed that subkaryotypic deletions and amplifications could accumulate over time, reinforcing that present culture regimes remain suboptimal. In all cultures the cell surface marker CD30, reportedly expressed on embryonal carcinoma but not karyoptically normal ESCs, was expressed on hESCs with both normal and abnormal karyotype, but was upregulated on the latter. © 2008 Mary Ann Liebert, Inc

The effect of ultrasound pretreatment on some selected physicochemical properties of black cumin (Nigella Sativa)

Background In the present study, the effects of ultrasound pretreatment parameters including irradiation time and power on the quantity of the extracted phenolic compounds quantity as well as on some selected physicochemical properties of the extracted oils including oil extraction efficiency, acidity and peroxide values, color, and refractive index of the extracted oil of black cumin seeds with the use of cold press have been studied. Methods For each parameter, three different levels (30, 60, and 90 W) for the ultrasound power and (30, 45, and 60 min) and for the ultrasound irradiation time were studied. Each experiment was performed in three replications. Results The achieved results revealed that, with enhancements in the applied ultrasound power, the oil extraction efficiency, acidity value, total phenolic content, peroxide value, and color parameters increased significantly (P 0.05). Conclusions In summary, it could be mentioned that the application of ultrasound pretreatment in the oil extraction might improve the oil extraction efficiency, the extracted oil’s quality, and the extracted phenolic compounds content.info:eu-repo/semantics/publishedVersio