scholarly journals Chaotic photon spheres in non-Euclidean billiard

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3367-3372 ◽  
Author(s):  
Dongyang Wang ◽  
Changxu Liu ◽  
Shuang Zhang ◽  
Che Ting Chan
Keyword(s):  
Chaotic Systems ◽  
Geodesic Equation ◽  
Extensive Study ◽  
Wave Chaos ◽  
Light Localization ◽  
Transition Position ◽  
Cavity System ◽  
Light Matter Interaction ◽  
Ray Chaos ◽  
Made In

AbstractWith the advancement in understanding of the physics inside chaotic systems, chaos has been harnessed from a nuisance to a beneficial factor in optical devices. Light–matter interaction in chaotic systems has been utilised for improving broadband energy harvesting and momentum transformations, achieving light localization beyond diffraction limit and even stabilizing the dynamics of high power laser. While extensive study about wave chaos has been made in deformed microcavities, investigation of how chaos dynamics evolves in curved space manifold remains elusive. Here, we study the non-Euclidean billiard of a torus-like manifold, which is a closed 2D cavity system with effective periodic boundaries. The ray chaotic behaviours on the deformed toroidal surface are explored using the geodesic equation. By tuning the deformation parameter of the torus, we observe the transition of the billiard from the ordered phase state to mixed phase states and then complete ray chaos. The photon sphere of the torus is identified as the transition position from ordered states to chaotic states. Compared with other chaotic behaviours resulted from the random scattering inside deformed cavities, we demonstrate chaotic dynamics purely on a curved surface, which may shed light on the better understanding of chaos in optics.

scholarly journals Studies on the moss flora of the Bío-Bío region of Chile

2006 ◽  
Vol 28 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Robert R. Ireland ◽  
Gilda Bellolio ◽  
Roberto Rodríguez ◽  
Juan Larraín
Keyword(s):  
South America ◽  
New Taxa ◽  
New Records ◽  
Recent Literature ◽  
Extensive Study ◽  
Central Chile ◽  
Number Of Species ◽  
South Central ◽  
Made In

An extensive study was made on the moss flora of the Bío-Bío Region (VIII Región) in south-central Chile in 2001-2003. Collections were made in all four provinces of the region: Arauco, Bío-Bío, Concepción and Ñuble. Approximately 265 localities in the region were explored with over 6,000 mosses collected in the four provinces. The mosses of this region had not previously been studied to any great extent and with part of the region’s environment being destroyed by the construction of several dams on one of the major rivers, the Bío-Bío, the study of this area seemed of utmost importance. Thus far, a total of 20 taxa were found which are new to Chile, making a total of 877 known for the country, with four new taxa known for South America. An additional 87 taxa are reported new only to the Bío-Bío Region. That number, together with some new records from the recent literature, increases the total for the Region from 190 to 300. It was determined from the 87 new taxa for the Bío-Bío Region that the majority (41) represent northern extensions of taxa, while a much smaller number (10) represent southern extensions. The remainder (36) fill in a gap in the distribution of the taxa between the northern and southern parts of the country. Many difficult species still remain to be identified and the number of species new to science, to Chile and to the Bío-Bío Region, is certain to increase when the remaining specimens are identified.

scholarly journals Plant-derived alkaloids as anti-viral agents

2020 ◽  
Vol 11 (4) ◽  
pp. 6174-6182
Author(s):  
Nagasathiya Krishnan ◽  
Velmurugan Devadasan ◽  
Pachaiappan Raman
Keyword(s):  
Viral Infections ◽  
Health And Safety ◽  
Extensive Study ◽  
Human Immune Deficiency Virus ◽  
Pharmacological Activities ◽  
Viral Pathogens ◽  
The Past ◽  
Medicinal Use ◽  
Human Immune ◽  
Made In

Humans are prone to many viral infections, most of them not causing diseases, and some will do. The new pandemic situation in global development and comfort to travel have highlighted their protection as a crucial problem in people’s health and safety even though significant advancements are being made in the making of vaccines and drugs. The provenance of viral mutants generally threatens immunisation and effective anti-viral treatments. The discovery of novel anti-viral drugs is, therefore of paramount importance. The secondary metabolites from the plants with pharmacological activities are regarded as an exemplary repository for this diagnosis.  An extensive study of phytochemicals and their mechanisms of action against the viruses might help in controlling harmful viruses. Many phytochemical entities, including terpenes, flavonoids, polyphenol, and phenolic compounds, have been studied for their anti-viral activity. Particularly in alkaloids, cutting edge study is making way to uncover innovative therapeutic strategies. Most of the alkaloids are being used as anti-viral agents, act against few prominent viral pathogens such as coronavirus (CoV), human immune deficiency virus (HIV), systemic acute respiratory syndrome (SARS) and respiratory virus (RSV). In this review, we intend to summarise the medicinal use of plant-derived alkaloids utilised to cure viral diseases in the past four decades.

Development and characterization of bio-composites using senegalia catechu resin

2021 ◽  
pp. 096739112110542
Author(s):  
Vinayagamoorthy R ◽  
Venkatakoteswararao G
Keyword(s):  
Thermal Characterization ◽  
Extensive Study ◽  
Positive Sign ◽  
Impact Loads ◽  
Synthetic Resin ◽  
Structural Investigations ◽  
Light Load ◽  
Mechanical Strengths ◽  
Made In

Owing to the increase in demand on bio-degradable materials, the present researches focus on the development of materials with full degradability. This research is intended to develop a bio-resin–based composite from senegalia catechu gum for light load automotive applications. The bio-resin obtained from the plant is processed with commercial polyester in order to make it as a functional resin for composite preparation. The synthesized resin is made in the form of structural materials by adding jute reinforcements in varying proportions. An extensive study on the various characters in comparison with the synthetic resin–based composites has been done which includes mechanical strengths analysis and thermal characters investigation. It is revealed that the bio-resin–based composites are good against tensile, flexural and impact loads as compared to that of the synthetic resin composites. In addition, it has been witnessed that the material with 40% weight of jute fabric is apt for offering highest resistance against tensile, flexural and impact loads. Micro-structural investigations proved that the bio-resin–based composites are superior in reducing the flaws and enhancing the bonding of resin with fibres as compared to that of the synthetic resin-based composites. Further, the thermal characterization showed that the bio-resin–based composites have high thermal stability as compared to the synthetic composites, and hence, a positive sign is obtained for bio-resin–based composites in both mechanical and thermal characters.

scholarly journals Design of Adaptive TSK Fuzzy Self-Organizing Recurrent Cerebellar Model Articulation Controller for Chaotic Systems Control

2021 ◽  
Vol 11 (4) ◽  
pp. 1567
Author(s):  
Shun-Yuan Wang ◽  
Chuan-Min Lin ◽  
Chen-Hao Li
Keyword(s):  
Chaotic Systems ◽  
Tracking Error ◽  
Extensive Study ◽  
Fuzzy Rules ◽  
Cerebellar Model Articulation Controller ◽  
Control Performance ◽  
Fuzzy Cmac ◽  
Structure Complexity ◽  
Takagi Sugeno ◽  
Self Organizing

The synchronization and control of chaos have been under extensive study by researchers in recent years. In this study, an adaptive Takagi–Sugeno–Kang (TSK) fuzzy self-organizing recurrent cerebellar model articulation controller (ATFSORC) is proposed, which is composed of a set of TSK fuzzy rules, a cerebellar model articulation controller (CMAC), a recurrent CMAC (RCMAC), a self-organizing CMAC (SOCMAC), and a compensation controller. Specifically, SOCMAC, RCMAC, and adaptive laws are adopted so that the association memory layers of ATFSORC can be modulated in accordance with the layer decision-making mechanism in order to reduce the structure complexity and improve the control performance of ATFSORC. Moreover, the Takagi–Sugeno–Kang fuzzy rules are introduced to increase the learning speed of ATFSORC, and the improved compensating controller is designed to dispel the errors between an ideal controller and the TFSORC. Moreover, the proposed ATFSORC is applied to chaotic systems in order to validate its performance and feasibility. Several simulation schemes are demonstrated to show the effectiveness of the proposed method. Simulation results show that the proposed ATFSORC can obtain a favorable control performance when the chaotic systems are operated at different parameters. Specifically, ATFSORC can achieve faster convergence of the tracking error than fuzzy CMAC (FCMAC) and CMAC.

scholarly journals Sverre Fehns museumsteori

1970 ◽  
pp. 75
Author(s):  
Hans Egede-Nissen
Keyword(s):  
17Th Century ◽  
Extensive Study ◽  
Material Objects ◽  
Historical Information ◽  
Historical Objects ◽  
Made In

Sverre Fehn and his theory of exhibitions In the 17th century a large barn was erected on the ruins of a medieval bishop's residence at Hamar in Norway. Today it has been transformed into a historical museum, Storhamarlåven. The exhibition of historical objects has been designed by the famous architect Sverre Fehn. In this paper, which is a chapter in a more extensive study of Fehn, the author analyses the exhibition against the background of Fehn's own writings and statements made in press interviews. The author finds that Fehn in his adherence to modernism, is akin to Elias Cannetti who has characterized 'history' as an old vampire sucking the blood out of young people's brains and who argues that people who do not make their way out of history are irretrievably lost. How can Fehn combine the modernistic rejection of everything with a taste for history and nationalism with the museological responsibility to further identity and factual historical information? Both aims to be achieved through the medium of material objects. 

Rhythmicity in the early swimming of anuran larvae

Development ◽  
1964 ◽  
Vol 12 (4) ◽  
pp. 665-671
Author(s):  
Michael Corner
Keyword(s):  
Tactile Stimulation ◽  
Extensive Study ◽  
The Body ◽  
Quantitative Characterization ◽  
Anatomical Basis ◽  
The Central Nervous System ◽  
Two Sides ◽  
The Waves ◽  
Made In

Previous observations of the development of somatic movements in amphibians concentrated their attention on ‘reflex’ mechanisms (for review, see Hooker, 1952). Extensive study has been made of the types of movement evoked by tactile stimulation at different stages in early development and on the anatomical basis for such responses. Emphasis was thus placed upon the formation of direct pathways through the central nervous system from receptor to effector. For the swimming movements, this approach was able to account for (a) the cranio-caudal wave of somite contractions, in response to sensory input from any part of the body surface, and (b) the existence of a phase difference between the waves on the two sides of the body. A quantitative characterization of behavior at successive stages has also been made, in terms of the distances travelled per response (cf. Detwiler, 1948; Sladeček, 1960).

STUDY OF A LARGE STEROID SPECTRUM IN NORMAL SUBJECTS AND HYPERTENSIVE PATIENTS

1960 ◽  
Vol XXXV (III) ◽  
pp. 413-425 ◽  
Author(s):  
Jacques Genest ◽  
Erich Koiw ◽  
Wojciech Nowaczynski ◽  
Thomas Sandor
Keyword(s):  
Healthy Volunteers ◽  
Intravenous Infusion ◽  
Fold Increase ◽  
Normal Subjects ◽  
Extensive Study ◽  
Malignant Hypertension ◽  
Hypertensive Patients ◽  
Significant Difference ◽  
Normotensive Subjects ◽  
Made In

ABSTRACT An extensive study made in 110 normal subjects and hypertensive patients has shown a statistically significant 2-fold mean increase in urinary aldosterone excretion and a statistically significant mean decrease in urinary pregnanetriol and in pregnanetriol/aldosterone ratio from groups of patients with essential, renal and malignant hypertension as compared to that of normal subjects. No significant difference was found in cortisone, cortisol and their tetrahydro derivatives, aetiocholanolone and the tetrahydro derivative of 17,21-dihydroxy-pregn-4-ene-3,20-dione excretion of hypertensive patients as compared to normotensive subjects. In four healthy volunteers, intravenous infusion of angiotensin was followed by a 2 to 10-fold increase in urinary aldosterone excretion.

scholarly journals Idiopathic Deep Vein Thrombosis and Subsequent Cancer: Suggestions for a Patient-Oriented and Practical Approach

2001 ◽  
Vol 7 (4) ◽  
pp. 321-324 ◽  
Author(s):  
Antonio Girolami
Keyword(s):  
Deep Vein Thrombosis ◽  
Extensive Study ◽  
Personal History ◽  
Vein Thrombosis ◽  
Wait And See ◽  
Deep Vein ◽  
The Relationship ◽  
Subsequent Cancer ◽  
Selection Of ◽  
Made In

The relationship between an idiopathic deep vein thrombosis and a cancer is well established. It is not clear yet whether all patients with an idiopathic deep vein thrombosis should be thoroughly investigated for an occult cancer or only some. As a matter of fact, once a physician is faced with a patient who has an idiopathic deep vein thrombosis, three approaches are possible, mainly: 1) a wait and see approach; 2) a limited investigation; and 3) an extensive or invasive investigation. No sure criteria for the selection of the patients who should be extensively investigated are available. Suggestions have been made in this regard. Negative family or personal history for thrombosis, advanced age, deep vein thrombosis of upper limbs, existence of silent deep vein thrombosis in contralateral leg, tendency to relapse and/or to migrate, constitutional symptoms, or smoking may represent important clues that may justify an extensive study. This patient-oriented approach is mainly based on the experience of the caring physician.

A STUDY OF THE MECHANISMS INVOLVED IN THE PRODUCTION OF IODINE-DEFICIENCY GOITER

1965 ◽  
Vol 49 (4) ◽  
pp. 610-628 ◽  
Author(s):  
Hugo Studer ◽  
Monte A. Greer
Keyword(s):  
Iodine Deficiency ◽  
Elevated Serum ◽  
Extensive Study ◽  
The Body ◽  
Total Evidence ◽  
High Iodine ◽  
Tsh Secretion ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Made In

ABSTRACT An extensive study of the temporal sequence of changes in thyroid function after initiation of a low iodine regimen has been made in rats. Variables measured include: thyroid weight, 131I uptake, monoiodotyrosine/diiodotyrosine (MIT/DIT) and triiodothyronine/thyroxine (T3/T4) ratios, iodide clearance, and 127I content. Also measured were protein-bound iodine (PBI), inorganic iodide and thyrotrophin (TSH) levels in the serum. Significant thyroid hypertrophy was produced during the first week and before there was a fall in serum PBI. Temporally related to the appearance of goiter were a rise in 131I uptake, MIT/DIT ratio and iodide clearance and a fall in thyroidal 127I concentration. In contrast, a fall in total thyroidal 127I appeared later and was closely correlated with a decline in serum PBI concentration and a rise in the thyroidal T3/T4 ratio. Manipulations such as hypophysectomy, injections of iodide, thyroxine or TSH, and refeeding a high iodine diet gave results consistent with the view that changes produced by iodine deficiency involve both autonomous and TSH-dependent thyroidal mechanisms. Although elevated serum TSH levels could not be demonstrated until after the first week of the iodine-deficient regimen, the total evidence of these studies permits the conclusion that increased TSH secretion is the most important factor in producing the thyroidal response to iodine deficiency. It is shown that homeostatic mechanisms allow maintenance of a normal level of circulating thyroid hormone in an iodine-deficient state until the body iodine pool becomes too severely depleted to supply adequate iodide substrate to the thyroid. The changes observed closely resemble those found in human iodine-deficient goiters. Although the large goiters produced after several weeks of an iodine-deficient regimen were hyperplastic, they could readily be converted to typical colloid goiters by feeding a high iodine diet for a few days.

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