180 research outputs found
How Disabled Readers Try to Remember Words
Studies of memory tasks with normal learners, involving letters and word-like patterns, indicate that recall is easier when stimuli present familiar patterns, either as pronounceable syllables (Gibson, 1965) or as contextual dependencies (Miller & Selfridge, 1950). Blumberg (1968), studying associative learning tasks, found brain injured children to have the least difficulty in making associations between visual non-word like stimuli and spoken words, while having greatest difficulty with visual word-like associations. Bakker (1967) reports that severely disabled readers were significantly poorer than better readers in the recall of meaningful, but not meaningless, sequences
Rotational Broadening of Atomic Spectral Features from Neutron Stars
The discovery of the first gravitationally redshifted spectral line from a
neutron star (NS) by Cottam, Paerels and Mendez has triggered theoretical
studies of the physics of atomic line formation in NS atmospheres. Chang,
Bildsten and Wasserman showed that the hydrogenic Fe H line formed
above the photosphere of a bursting NS is intrinsically broad. We now include
rotational broadening within general relativity and compare the resulting
profile to that observed during Type I bursts from EXO 0748-676. We show that
the fine structure splitting of the line precludes a meaningful constraint on
the radius. Our fitting of the data show that the line forming Fe column is
and
gravitational redshift with 95% confidence. We
calculate the detectability of this spectral feature for a large range of spins
and inclinations assuming that the emission comes from the entire surface. We
find that at 300 (600) Hz only 10-20% (5-10%) of NSs would have spectral
features as deep as that seen in EXO 0748-676.Comment: 4 pages, 4 figures, to appear in ApJ Letter
New Types of Thermodynamics from -Dimensional Black Holes
For normal thermodynamic systems superadditivity , homogeneity \H and
concavity \C of the entropy hold, whereas for -dimensional black holes
the latter two properties are violated. We show that -dimensional black
holes exhibit qualitatively new types of thermodynamic behaviour, discussed
here for the first time, in which \C always holds, \H is always violated
and may or may not be violated, depending of the magnitude of the black
hole mass. Hence it is now seen that neither superadditivity nor concavity
encapsulate the meaning of the second law in all situations.Comment: WATPHYS-TH93/05, Latex, 10 pgs. 1 figure (available on request), to
appear in Class. Quant. Gra
Overview of BIM integration into the Construction Sector in European Member States and European Union Acquis
The amount of information involved in any construction project and the necessity of control of time, cost and waste, has established Building Information Modelling (BIM) as an integral part of construction sector towards achieving adequate communication of information among various parties involved in construction projects. Moreover, it can be considered as a valuable tool for the optimum selection of materials, systems and design decisions, regarding not only the improve of a structure’s performance, but also in terms of reducing its carbon footprint during its life cycle. The study attempts to present the integration of BIM into the national legislation of European Member States, with a special focus on the energy related aspects of BIM analysis. This study performs an overview of the introduction of BIM into different aspects and requirements of the EU Member States building practices, through a comprehensive literature and legislation review of relative legislative documents of the construction sector. According to the findings of this overview study, the concept of BIM has already been incorporated in many aspects of the Acquis of EU Member States, which is recognized as a valuable tool to be exploited by the construction sector, however there is still room for development in this area. The study has revealed that especially in the energy assessment of the built environment, BIM applications are still lacking from the European Legislation. Examples and good practices of employing BIM for the implementation of the European Energy targets in the building sector are also presented and discussed. The findings of this study aim to shed light on the needs and requirements in the field of BIM development for the construction sector, as well as to indicate gaps and weaknesses of the European Member States Acquis towards harmonizing with BIM practices
Self-completeness and spontaneous dimensional reduction
A viable quantum theory of gravity is one of the biggest challenges facing
physicists. We discuss the confluence of two highly expected features which
might be instrumental in the quest of a finite and renormalizable quantum
gravity -- spontaneous dimensional reduction and self-completeness. The former
suggests the spacetime background at the Planck scale may be effectively
two-dimensional, while the latter implies a condition of maximal compression of
matter by the formation of an event horizon for Planckian scattering. We
generalize such a result to an arbitrary number of dimensions, and show that
gravity in higher than four dimensions remains self-complete, but in lower
dimensions it is not. In such a way we established an "exclusive disjunction"
or "exclusive or" (XOR) between the occurrence of self-completeness and
dimensional reduction, with the goal of actually reducing the unknowns for the
scenario of the physics at the Planck scale. Potential phenomenological
implications of this result are considered by studying the case of a
two-dimensional dilaton gravity model resulting from dimensional reduction of
Einstein gravity.Comment: 12 pages, 3 figures; v3: final version in press on Eur. Phys. J. Plu
Exact Black Hole and Cosmological Solutions in a Two-Dimensional Dilaton-Spectator Theory of Gravity
Exact black hole and cosmological solutions are obtained for a special
two-dimensional dilaton-spectator () theory of gravity. We show how
in this context any desired spacetime behaviour can be determined by an
appropriate choice of a dilaton potential function and a ``coupling
function'' in the action. We illustrate several black hole solutions
as examples. In particular, asymptotically flat double- and multiple- horizon
black hole solutions are obtained. One solution bears an interesting
resemblance to the string-theoretic black hole and contains the same
thermodynamic properties; another resembles the Reissner-Nordstrom
solution. We find two characteristic features of all the black hole solutions.
First the coupling constants in must be set equal to constants of
integration (typically the mass). Second, the spectator field and its
derivative both diverge at any event horizon. A test particle with
``spectator charge" ({\it i.e.} one coupled either to or ),
will therefore encounter an infinite tidal force at the horizon or an
``infinite potential barrier'' located outside the horizon respectively. We
also compute the Hawking temperature and entropy for our solutions. In
cosmology, two non-singular solutions which resemble two exact solutions
in string-motivated cosmology are obtained. In addition, we construct a
singular model which describes the standard non-inflationary big bang
cosmology (). Motivated by the
similaritiesbetween and gravitational field equations in
cosmology, we briefly discuss a special dilaton-spectator action
constructed from the bosonic part of the low energy heterotic string action andComment: 34 pgs. Plain Tex, revised version contains some clarifying comments
concerning the relationship between the constants of integration and the
coupling constants
Naringenin-functionalized multi-walled carbon nanotubes: a potential approach for site-specific remote-controlled anticancer delivery for the treatment of lung cancer cells
Multi-walled carbon nanotubes functionalized with naringenin have been developed as new drug carriers to improve the performance of lung cancer treatment. The nanocarrier was characterized by Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy, Raman Spectroscopy, and Differential Scanning Calorimetry (DSC). Drug release rates were determined in vitro by the dialysis method. The cytotoxic profile was evaluated using the MTT assay, against a human skin cell line (hFB) as a model for normal cells, and against an adenocarcinomic human alveolar basal epithelial (A569) cell line as a lung cancer in vitro model. The results demonstrated that the functionalization of carbon nanotubes with naringenin occurred by non-covalent interactions. The release profiles demonstrated a pH-responsive behavior, showing a prolonged release in the tumor pH environment. The naringenin-functionalized carbon nanotubes showed lower cytotoxicity on non-malignant cells (hFB) than free naringenin, with an improved anticancer effect on malignant lung cells (A549) as an in vitro model of lung cancer.This work was supported by the Banco do Nordeste (grant FUNDECI/2016.0015), Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Apoio à Pesquisa e à Inovação Tecnológica do Estado de Sergipe (Fapitec) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Eliana B. Souto would like to acknowledge the contributions from the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) for the projects M-ERA-NET/0004/2015-PAIRED and UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio
Fermions Tunnelling from Black Holes
We investigate the tunnelling of spin 1/2 particles through event horizons.
We first apply the tunnelling method to Rindler spacetime and obtain the Unruh
temperature. We then apply fermion tunnelling to a general non-rotating black
hole metric and show that the Hawking temperature is recovered.Comment: 22 pages, v2: added references, v3: fixed minor typos, v4: added a
new section applying fermion tunnelling method to Kruskal-Szekers
coordinates, fixed minor typo, and added references, v5: modified
introduction and conclusion, fixed typo
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