scholarly journals LARGE QUANTUM GRAVITY EFFECTS: CYLINDRICAL WAVES IN FOUR DIMENSIONS

2000 ◽  
Vol 09 (06) ◽  
pp. 669-686 ◽  
Author(s):  
MARÍA E. ANGULO ◽  
GUILLERMO A. MENA MARUGÁN
Keyword(s):  
Quantum Gravity ◽  
Symmetry Axis ◽  
Point Of View ◽  
Three Dimensions ◽  
Asymptotic Region ◽  
Four Dimensions ◽  
Cylindrical Waves ◽  
Significant Difference ◽  
Gravity Effects ◽  
Linearly Polarized

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein–Gordon) field in three dimensions. The quantization of this latter system was performed by Ashtekar and Pierri in a recent work. Employing that quantization, we obtain here a complete quantum theory which describes the four-dimensional geometry of the Einstein–Rosen waves. In particular, we construct regularized operators to represent the metric. It is shown that the results achieved by Ashtekar about the existence of important quantum gravity effects in the Einstein–Maxwell system at large distances from the symmetry axis continue to be valid from a four-dimensional point of view. The only significant difference is that, in order to admit an approximate classical description in the asymptotic region, states that are coherent in the Maxwell field need not contain a large number of photons anymore. We also analyze the metric fluctuations on the symmetry axis and argue that they are generally relevant for all of the coherent states.

scholarly journals Probing quantum gravity effects with quantum mechanical oscillators

2020 ◽  
Vol 74 (9) ◽  
Author(s):  
Michele Bonaldi ◽  
Antonio Borrielli ◽  
Avishek Chowdhury ◽  
Gianni Di Giuseppe ◽  
Wenlin Li ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Quantum Physics ◽  
Deformation Parameter ◽  
Thermal State ◽  
Classical Trajectory ◽  
Point Of View ◽  
Gravity Models ◽  
Gravity Effects ◽  
The Status ◽  
Mechanical Oscillators

Abstract Phenomenological models aiming to join gravity and quantum mechanics often predict effects that are potentially measurable in refined low-energy experiments. For instance, modified commutation relations between position and momentum, that account for a minimal scale length, yield a dynamics that can be codified in additional Hamiltonian terms. When applied to the paradigmatic case of a mechanical oscillator, such terms, at the lowest order in the deformation parameter, introduce a weak intrinsic nonlinearity and, consequently, deviations from the classical trajectory. This point of view has stimulated several experimental proposals and realizations, leading to meaningful upper limits to the deformation parameter. All such experiments are based on classical mechanical oscillators, i.e., excited from a thermal state. We remark indeed that decoherence, that plays a major role in distinguishing the classical from the quantum behavior of (macroscopic) systems, is not usually included in phenomenological quantum gravity models. However, it would not be surprising if peculiar features that are predicted by considering the joined roles of gravity and quantum physics should manifest themselves just on purely quantum objects. On the basis of this consideration, we propose experiments aiming to observe possible quantum gravity effects on macroscopic mechanical oscillators that are preliminary prepared in a high purity state, and we report on the status of their realization. Graphical abstract

scholarly journals EFFECT OF A STEM-ORIENTED COURSE ON STUDENTS’ MARINE SCIENCE MOTIVATION, INTEREST, AND ACHIEVEMENTS

2021 ◽  
Vol 20 (1) ◽  
pp. 134-145
Author(s):  
Liang-Ting Tsai ◽  
Cheng-Chieh Chang ◽  
Hao-Ti Cheng
Keyword(s):  
Science Achievement ◽  
Learning Motivation ◽  
Three Dimensions ◽  
Control Group ◽  
Marine Science ◽  
Four Dimensions ◽  
9Th Grade ◽  
Significant Difference ◽  
The Subject ◽  
Experimental Group

In recent years, marine science education has received increasing attention around the world, but the integration of STEM education into the marine curriculum is rarely applied to lower-secondary schools. The purpose of this research was to determine the effect of a teaching module on the topic of marine science, developed using a STEM approach, on the motivation, interest, and marine science achievements. The 9th-grade students from two classes in a Taiwanese public school were recruited in this study. Students in the experimental group were taught using the STEM course. Students in the control group were taught in a traditional didactic teaching course. Pre- and post-tests were used to determine marine science achievement, interest, and learning motivation. The experimental group gained significantly superior scores in three out of four dimensions towards motivation and two out of three dimensions interest. A significant difference was found between the experimental group and the control group, with the former showing increased marine science achievement over the latter in higher-order thinking; however, no significant differences were with respect to cognition. It is concluded that involving STEM-based implementations in teaching, the subject “Marine Science” increases the success rate and attitude towards the subject of students. Keywords: learning interest, learning motivation, marine science achievement, STEM

QUANTUM CYLINDRICAL WAVES AND PARAMETRIZED FIELD THEORY

2006 ◽  
Vol 15 (10) ◽  
pp. 1743-1752 ◽  
Author(s):  
MADHAVAN VARADARAJAN
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Quantum Gravity ◽  
Flat Space ◽  
Space Time ◽  
Gravitational Fields ◽  
Cylindrical Waves ◽  
Cylindrically Symmetric ◽  
Gravity Effects ◽  
Free Scalar

In this article, we review some illustrative results in the study of two related toy models for quantum gravity, namely cylindrical waves (which are cylindrically symmetric gravitational fields)and parametrized field theory (which is just free scalar field theory on a flat space–time in generally covariant disguise). In the former, we focus on the phenomenon of unexpected large quantum gravity effects in regions of weak classical gravitational fields and on an analysis of causality in a quantum geometry. In the latter, we focus on Dirac quantization, argue that this is related to the unitary implementability of free scalar field evolution along curved foliations of the flat space–time and review the relevant results for unitary implementability.

LABORATORY TESTS OF THYROID FUNCTION IN HYPERTHYROIDISM II.

1969 ◽  
Vol 62 (4_Suppla) ◽  
pp. S23-S35
Author(s):  
B.-A. Lamberg ◽  
O. P. Heinonen ◽  
K. Liewendahl ◽  
G. Kvist ◽  
M. Viherkoski ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Laboratory Tests ◽  
Goodness Of Fit ◽  
Point Of View ◽  
Accurate Estimation ◽  
Diagnostic Efficiency ◽  
Normal Limits ◽  
Significant Difference ◽  
Crossing Point ◽  
Hyperthyroid Patients

ABSTRACT The distributions of 13 variables based on 10 laboratory tests measuring thyroid function were studied in euthyroid controls and in patients with toxic diffuse or toxic multinodular goitre. Density functions were fitted to the empirical data and the goodness of fit was evaluated by the use of the χ2-test. In a few instances there was a significant difference but the material available was in some respects too small to allow a very accurate estimation. The normal limits for each variable was defined by the 2.5 and 97.5 percentiles. It appears that in some instances these limits are too rigorous from the practical point of view. It is emphasized that the crossing point of the functions for euthyroid controls and hyperthyroid patients may be a better limit to use. In a preliminary analysis of the diagnostic efficiency the variables of total or free hormone concentration in the blood proved clearily superior to all other variables.

Governance Disclosure on the Internet by Leading Indian Public Sector Companies

Think India ◽  
2019 ◽  
Vol 22 (2) ◽  
pp. 174-187
Author(s):  
Harmandeep Singh ◽  
Arwinder Singh
Keyword(s):  
Public Sector ◽  
Financial Information ◽  
Three Dimensions ◽  
The Internet ◽  
Web Pages ◽  
Non Profit ◽  
Index Approach ◽  
Significant Difference ◽  
Governance Disclosure ◽  
The Web

Nowadays, internet satisfying people with different services related to different fields. The profit, as well as non-profit organization, uses the internet for various business purposes. One of the major is communicated various financial as well as non-financial information on their respective websites. This study is conducted on the top 30 BSE listed public sector companies, to measure the extent of governance disclosure (non-financial information) on their web pages. The disclosure index approach to examine the extent of governance disclosure on the internet was used. The governance index was constructed and broadly categorized into three dimensions, i.e., organization and structure, strategy & Planning and accountability, compliance, philosophy & risk management. The empirical evidence of the study reveals that all the Indian public sector companies have a website, and on average, 67% of companies disclosed some kind of governance information directly on their websites. Further, we found extreme variations in the web disclosure between the three categories, i.e., The Maharatans, The Navratans, and Miniratans. However, the result of Kruskal-Wallis indicates that there is no such significant difference between the three categories. The study provides valuable insights into the Indian economy. It explored that Indian public sector companies use the internet for governance disclosure to some extent, but lacks symmetry in the disclosure. It is because there is no such regulation for web disclosure. Thus, the recommendation of the study highlighted that there must be such a regulated framework for the web disclosure so that stakeholders ensure the transparency and reliability of the information.

scholarly journals Using Wearable Cameras to Assess Foods and Beverages Omitted in 24 Hour Dietary Recalls and a Text Entry Food Record App

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1806
Author(s):  
Virginia Chan ◽  
Alyse Davies ◽  
Lyndal Wellard-Cole ◽  
Silvia Lu ◽  
Hoi Ng ◽  
...  
Keyword(s):  
Dietary Assessment ◽  
Fats And Oils ◽  
Point Of View ◽  
Self Report ◽  
Smartphone App ◽  
Food Record ◽  
Post Hoc Analysis ◽  
Significant Difference ◽  
Post Hoc ◽  
Paired T Test

Technology-enhanced methods of dietary assessment may still face common limitations of self-report. This study aimed to assess foods and beverages omitted when both a 24 h recall and a smartphone app were used to assess dietary intake compared with camera images. For three consecutive days, young adults (18–30 years) wore an Autographer camera that took point-of-view images every 30 seconds. Over the same period, participants reported their diet in the app and completed daily 24 h recalls. Camera images were reviewed for food and beverages, then matched to the items reported in the 24 h recall and app. ANOVA (with post hoc analysis using Tukey Honest Significant Difference) and paired t-test were conducted. Discretionary snacks were frequently omitted by both methods (p < 0.001). Water was omitted more frequently in the app than in the camera images (p < 0.001) and 24 h recall (p < 0.001). Dairy and alternatives (p = 0.001), sugar-based products (p = 0.007), savoury sauces and condiments (p < 0.001), fats and oils (p < 0.001) and alcohol (p = 0.002) were more frequently omitted in the app than in the 24 h recall. The use of traditional self-report methods of assessing diet remains problematic even with the addition of technology and finding new objective methods that are not intrusive and are of low burden to participants remains a challenge.

scholarly journals An exceptionally preserved conulariid from Ordovician erratics of Northern European Lowlands

PalZ ◽  
2021 ◽  
Author(s):  
Consuelo Sendino ◽  
Martin M. Bochmann
Keyword(s):  
Internal Structure ◽  
Late Pleistocene ◽  
Point Of View ◽  
Three Dimensions ◽  
Northern European ◽  
Current Location ◽  
Transport Direction ◽  
First Time ◽  
Erratic Boulder

AbstractA conulariid preserved in three dimensions from Ordovician fluvioglacial erratics of the Northern European Lowlands (North German Plain) is described under open nomenclature. It is assigned to the genus Conularia with similarities to Baltoscandian conulariids. The lithology of the erratic boulder and fauna contained in it provide important information on the origin and transport direction of the sediment preserved in a kame from the Saalian glaciation. This paper deals with the site of origin of the boulder in Baltoscandia analysing the comprised palaeofauna, from a palaeostratigraphic and palaeogeographic point of view, from its deposition in Ordovician times until its arrival at its current location in the Late Pleistocene. It also reveals for the first time the internal structure of the conulariid aperture.

On Five Lines, in Space of Four Dimensions, which lie upon a, Quadric Threefold and the Normal Quartic Curves of which they are Chords

1924 ◽  
Vol 22 (2) ◽  
pp. 189-199
Author(s):  
F. Bath
Keyword(s):  
Three Dimensions ◽  
Apparent Contradiction ◽  
Four Dimensions ◽  
Quartic Curve ◽  
Lines In Space ◽  
Quadric Threefold ◽  
Quartic Curves

The connexion between the conditions for five lines of S4(i) to lie upon a quadric threefold,and (ii) to be chords of a normal quartic curve,leads to an apparent contradiction. This difficulty is explained in the first paragraph below and, subsequently, two investigations are given of which the first uses, mainly, properties of space of three dimensions.

scholarly journals Influence of the measure on simplicial quantum gravity in four dimensions

1992 ◽  
Vol 69 (5) ◽  
pp. 713-716 ◽  
Author(s):  
Wolfgang Beirl ◽  
Erwin Gerstenmayer ◽  
Harold Markum
Keyword(s):  
Quantum Gravity ◽  
Four Dimensions
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