scholarly journals Torus-Breakdown Near a Heteroclinic Attractor: A Case Study

2021 ◽  
Vol 31 (10) ◽  
pp. 2130029
Author(s):  
Luísa Castro ◽  
Alexandre Rodrigues

There are few explicit examples in the literature of vector fields exhibiting observable chaos that may be proved analytically. This paper reports numerical experiments performed for an explicit two-parameter family of [Formula: see text]-symmetric vector fields whose organizing center exhibits an attracting heteroclinic network linking two saddle-foci. Each vector field in the family is the restriction to [Formula: see text] of a polynomial vector field in [Formula: see text]. We investigate global bifurcations due to symmetry-breaking and we detect strange attractors via a mechanism called Torus-Breakdown. We explain how an attracting torus gets destroyed by following the changes in the unstable manifold of a saddle-focus. Although a complete understanding of the corresponding bifurcation diagram and the mechanisms underlying the dynamical changes is out of reach, we uncover complex patterns for the symmetric family under analysis, using a combination of theoretical tools and computer simulations. This article suggests a route to obtain rotational horseshoes and strange attractors; additionally, we make an attempt to elucidate some of the bifurcations involved in an Arnold tongue.

1985 ◽  
Vol 5 (1) ◽  
pp. 27-46 ◽  
Author(s):  
Colin Boyd

AbstractA class of vector fields on the 2-torus, which includes Cherry fields, is studied. Natural paths through this class are defined and it is shown that the parameters for which the vector field is unstable is the closure ofhas irrational rotation number}, where ƒ is a certain map of the circle andRtis rotation throught. This is shown to be a Cantor set of zero Hausdorff dimension. The Cherry fields are shown to form a family of codimension one submanifolds of the set of vector fields. The natural paths are shown to be stable paths.


1996 ◽  
Vol 5 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Chris Halpin ◽  
Barbara Herrmann ◽  
Margaret Whearty

The family described in this article provides an unusual opportunity to relate findings from genetic, histological, electrophysiological, psychophysical, and rehabilitative investigation. Although the total number evaluated is large (49), the known, living affected population is smaller (14), and these are spread from age 20 to age 59. As a result, the findings described above are those of a large-scale case study. Clearly, more data will be available through longitudinal study of the individuals documented in the course of this investigation but, given the slow nature of the progression in this disease, such studies will be undertaken after an interval of several years. The general picture presented to the audiologist who must rehabilitate these cases is that of a progressive cochlear degeneration that affects only thresholds at first, and then rapidly diminishes speech intelligibility. The expected result is that, after normal language development, the patient may accept hearing aids well, encouraged by the support of the family. Performance and satisfaction with the hearing aids is good, until the onset of the speech intelligibility loss, at which time the patient will encounter serious difficulties and may reject hearing aids as unhelpful. As the histological and electrophysiological results indicate, however, the eighth nerve remains viable, especially in the younger affected members, and success with cochlear implantation may be expected. Audiologic counseling efforts are aided by the presence of role models and support from the other affected members of the family. Speech-language pathology services were not considered important by the members of this family since their speech production developed normally and has remained very good. Self-correction of speech was supported by hearing aids and cochlear implants (Case 5’s speech production was documented in Perkell, Lane, Svirsky, & Webster, 1992). These patients received genetic counseling and, due to the high penetrance of the disease, exhibited serious concerns regarding future generations and the hope of a cure.


Author(s):  
Hendri Wasito ◽  
Hening Pratiwi ◽  
Adi Wibowo ◽  
Nia Kurnia Solihat

Drugs are an important component of health services that are the needs of the community. There is still a lack ofcommunity knowledge of medicines and management especially for family members, hence an educational effort as well asimprovement of quality of drug management in family through training program and mentoring by pharmacist. Thiscommunity service activity aims to determine the knowledge and attitude of the community in managing drugs in the familyand improve the quality of drug management by the community in the family. The activity was conducted in SidasariWetanKubangkangkung Village Kawunganten Cilacap. The workshop on drug management in family was conducted by pharmaciststo the 33 participants. Data collection was done by using questionnaire and observation through home visit. The result of theactivity shows that the increase of knowledge and attitude of the society in managing drugs in the familywere 10% and 7%,respectively. Workshop activities and mentoring by pharmacists can provide benefits and behavioral changes in family drugsmanagement.


2012 ◽  
Author(s):  
Asimina Vasalou ◽  
Anne-Marie Oostveen ◽  
Adam N. Joinson
Keyword(s):  

2021 ◽  
Vol 14 ◽  
pp. 194008292110281
Author(s):  
Elène Haave-Audet ◽  
Doris Audet ◽  
Michelle Monge-Velazquez ◽  
Eleanor Flatt ◽  
Andrew Whitworth

Introduction: Background and Research Aims: Assessing biodiversity recovery is key to determine whether the objectives of habitat restoration for conservation are met. Many restoration initiatives use cross-sectional comparisons of wildlife communities to infer restoration impact instead of longitudinal assessments from a baseline state. Using an indicator of biodiversity in the neotropics— bats— we demonstrate how assessing community diversity and composition in an area targeted for restoration prior to implementation, and when compared to surrounding intact forest, provides the groundwork to track changes in the community post-restoration. Methods We assessed bat communities by 1) using mist-net surveys to identify species in the family Phyllostomidae (leaf-nosed bats), and 2) conducting acoustic surveys to identify non-phyllostomid species (aerial insectivores). Results For both groups, we found that areas targeted for restoration had similar diversity as the surrounding forest, but the two habitat types differed in community composition. Phyllostomids were captured at higher rates in forest, but aerial insectivores were detected at higher rates in restoration habitat. Conclusion Our baseline assessment revealed unexpected diversity in areas targeted for restoration. The presence of all trophic groups in restoration habitat suggests that bats provide key ecosystem services in the restoration process, such as through seed dispersal, pollination and insect pest control. Implications for Conservation: Conducting a baseline survey of bats in areas targeted for restoration demonstrated that the community was not species poor at the baseline and was different from the surrounding forest, allowing us to better track restoration success and the effects of different restoration treatments.


Author(s):  
J. J. Nuño-Ballesteros ◽  
R. Oset Sinha

AbstractWe study liftable vector fields of smooth map-germs. We show how to obtain the module of liftable vector fields of any map-germ of finite singularity type from the module of liftable vector fields of a stable unfolding of it. As an application, we obtain the liftable vector fields for the family $$H_k$$ H k in Mond’s list. We then show the relation between the liftable vector fields of a stable germ and its augmentations.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Graziano Crasta ◽  
Virginia De Cicco ◽  
Annalisa Malusa

AbstractWe introduce a family of pairings between a bounded divergence-measure vector field and a function u of bounded variation, depending on the choice of the pointwise representative of u. We prove that these pairings inherit from the standard one, introduced in [G. Anzellotti, Pairings between measures and bounded functions and compensated compactness, Ann. Mat. Pura Appl. (4) 135 1983, 293–318], [G.-Q. Chen and H. Frid, Divergence-measure fields and hyperbolic conservation laws, Arch. Ration. Mech. Anal. 147 1999, 2, 89–118], all the main properties and features (e.g. coarea, Leibniz, and Gauss–Green formulas). We also characterize the pairings making the corresponding functionals semicontinuous with respect to the strict convergence in \mathrm{BV}. We remark that the standard pairing in general does not share this property.


2021 ◽  
pp. tobaccocontrol-2020-056145 ◽  
Author(s):  
Ollie Ganz ◽  
Mary Hrywna ◽  
Kevin R J Schroth ◽  
Cristine D Delnevo

In 2009, the Family Smoking Prevention and Tobacco Control Act (TCA) granted the U.S. Food and Drug Administration (FDA) regulatory authority over tobacco products, although initially this only included cigarettes, smokeless tobacco and roll-your-own tobacco. In 2016, the deeming rule extended regulatory authority to include all tobacco products, including cigars. The deeming rule prohibited the introduction of new tobacco products into the marketplace without proper marketing authorisation and laid out pathways for tobacco companies to follow. The deeming rule should have frozen the cigar marketplace in 2016. In this paper, we describe how the cigarillo marketplace, nevertheless, continues to diversify with new brands, flavors, styles and packaging sizes entering the market regularly. As an example, we highlight recent promotional efforts by Swedish Match North America (Swedish Match) for their popular cigarillo brands, including White Owl, Night Owl and Garcia y Vega’s Game brand. We argue that ambiguities in the TCA make it unclear whether Swedish Match’s seemingly new cigarillos fit the definition of new tobacco products and, if so, whether they are on the market legally. Swedish Match and other cigarillo companies may be taking advantage of these ambiguities to promote a variety of cigarillo flavors and styles in innovative ways. Given that cigars are combustible tobacco products that pose many of the same risks as cigarettes, this business practice raises significant concerns regarding the protection of public health, particularly among young people.


2019 ◽  
Vol 16 (11) ◽  
pp. 1950180 ◽  
Author(s):  
I. P. Lobo ◽  
G. G. Carvalho

Motivated by the hindrance of defining metric tensors compatible with the underlying spinor structure, other than the ones obtained via a conformal transformation, we study how some geometric objects are affected by the action of a disformal transformation in the closest scenario possible: the disformal transformation in the direction of a null-like vector field. Subsequently, we analyze symmetry properties such as mutual geodesics and mutual Killing vectors, generalized Weyl transformations that leave the disformal relation invariant, and introduce the concept of disformal Killing vector fields. In most cases, we use the Schwarzschild metric, in the Kerr–Schild formulation, to verify our calculations and results. We also revisit the disformal operator using a Newman–Penrose basis to show that, in the null-like case, this operator is not diagonalizable.


2001 ◽  
Vol 8 (1) ◽  
pp. 31-34
Author(s):  
Allan Macinnes

This paper makes an important, interdisciplinary contribution, to the ongoing debate on the transition from clanship to capitalism. Integral to this contribution is the important distinction between capitalism as an individualist ideology and capitalist societies where individualism is a widespread but not necessarily a universal ideology. His concern is not with the bipolar opposition of landlord and people which tends to dominate debates on the land issue in the Highlands. Instead, he focuses on material culture change in relation to landscape organisation, settlement patterns and morphology in order to examine how social relationships were structured during the critical period of estate re-orientation often depicted progressively as Improvement but regressively as clearance through the removal and relocation of population. His case study on Kintyre is particularly valuable. By scrutinising spatial as well as social relationships Dalglish demonstrates that clanship was based as much on daily practices of living as on an patrimonial ideology of kinship, practices which led the House of Argyll to attempt the reinvention of concepts of occupancy in order to emphasise the importance of the individual over the family through partitioned space.


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