scholarly journals Sphere tangencies, line incidences and Lie’s line-sphere correspondence

2021 ◽  
pp. 1-21
Author(s):  
JOSHUA ZAHL
Keyword(s):  
Heisenberg Group ◽  
Contact Geometry ◽  
Three Dimensions ◽  
Incidence Geometry ◽  
Significant Progress ◽  
The Past ◽  
Three Space

Abstract Two spheres with centers p and q and signed radii r and s are said to be in contact if |p–q|2=(r–s)2. Using Lie’s line-sphere correspondence, we show that if F is a field in which –1 is not a square, then there is an isomorphism between the set of spheres in F3 and the set of lines in a suitably constructed Heisenberg group that is embedded in (F[i])3; under this isomorphism, contact between spheres translates to incidences between lines. In the past decade there has been significant progress in understanding the incidence geometry of lines in three space. The contact-incidence isomorphism allows us to translate statements about the incidence geometry of lines into statements about the contact geometry of spheres. This leads to new bounds for Erdős’ repeated distances problem in F3, and improved bounds for the number of point-sphere incidences in three dimensions. These new bounds are sharp for certain ranges of parameters.

The Sea Fight Tomorrow

2018 ◽  
Author(s):  
Donald C. Williams
Keyword(s):  
Three Dimensions ◽  
The Past ◽  
The World ◽  
The Future ◽  
Metaphysics Of Time ◽  
Manifold Theory ◽  
Dimensions Of Space

This chapter is the first of this book to deal specifically with the metaphysics of time. This chapter defends the pure manifold theory of time. On this view, time is just another dimension of extent like the three dimensions of space, the past, present, and future are equally real, and the world is at bottom tenseless. What is true is eternally true. For example, it is now true that there will be a sea fight tomorrow or that there will not be a sea fight tomorrow. It is argued that the pure manifold theory does not entail fatalism and that contingent statements about the future do not imply that only the past and present exist.

scholarly journals Spontaneous deformation of protocatechuic acid crystals

1949 ◽  
Vol 197 (1050) ◽  
pp. 283-294 ◽  
Keyword(s):  
Protocatechuic Acid ◽  
Motion Pictures ◽  
Extensive Study ◽  
The Other ◽  
Three Dimensions ◽  
Stable Configuration ◽  
Unique Case ◽  
The Past ◽  
Spontaneous Deformation ◽  
Lattice Planes

In this paper an extensive study is reported of the very remarkable, and thus far apparently unique, case of the deformation in three dimensions of protocatechuic acid, to which attention was drawn many years ago by Otto Lehmann. The deformations are spontaneous, and are probably due to progressive gliding of the lattice planes, which exist in two configurations, one stable and the other unstable, the latter being the condition of the long prismatic rods when they first form. Such a prism presently deforms into a zigzag crystal, with stable and unstable sections in alternation which, with continuation of the deformation, becomes again straight, but now in the stable configuration. The bending is progressive, like that of an umbrella case, pendant from the end of an oblique cane pointed down, when the latter is pushed into it. The movements are so rapid that motion pictures, made with a microscope, were necessary for the observation of certain stages of the deformation. The deformations have been shown to many chemists and physicists during the past decade or more, none of whom had ever seen or heard of this remarkable type of crystal movement. The deformations are usually observed as the warm saturated solution cools, but they also occur after the crystal has been dried for many hours.

DESIGN DISCOURSE AND THE COGNITIVE SCIENCE OF DESIGN

2014 ◽  
Vol 79 (1) ◽  
pp. 37-53
Author(s):  
Jeroen de Ridder
Keyword(s):  
Cognitive Science ◽  
Science And Religion ◽  
The Other ◽  
Significant Progress ◽  
The Past ◽  
The One ◽  
Bare Bones ◽  
Single Focus

Much of Alvin Plantinga’s Where the Conflict Really Lies(2011) will contain few surprises for those who have been following his work over the past decades. This —I hasten to add — is nothing against the book. The fact alone that his ideas on various topics, which have appeared scattered throughout the literature, are now actualized, applied to the debate about the (alleged) conflict between science and religion, and organized into an overarching argument with a single focus makes this book worthwhile. Moreover, I see this book making significant progress on two opposite ends of the spectrum of views about science and religion. On the one end, we find the so-called new atheists and other conflict-mongers. Compared to the overheated rhetoric that oozes from their writings, this book is a breath of fresh air. Plantinga cuts right to the chase and soberly exposes the bare bones of the new atheists’ arguments. It immediately becomes clear how embarrassingly bare these bones really are. On the other end of the spectrum are theologians and scientists who envisage harmony and concord between science and religion.

scholarly journals Calcium Signaling in Plant Programmed Cell Death

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1089
Author(s):  
Huimin Ren ◽  
Xiaohong Zhao ◽  
Wenjie Li ◽  
Jamshaid Hussain ◽  
Guoning Qi ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Abiotic Stresses ◽  
Animal Studies ◽  
Future Research ◽  
Significant Progress ◽  
Biotic And Abiotic Stresses ◽  
Stress Perception ◽  
The Past

Programmed cell death (PCD) is a process intended for the maintenance of cellular homeostasis by eliminating old, damaged, or unwanted cells. In plants, PCD takes place during developmental processes and in response to biotic and abiotic stresses. In contrast to the field of animal studies, PCD is not well understood in plants. Calcium (Ca2+) is a universal cell signaling entity and regulates numerous physiological activities across all the kingdoms of life. The cytosolic increase in Ca2+ is a prerequisite for the induction of PCD in plants. Although over the past years, we have witnessed significant progress in understanding the role of Ca2+ in the regulation of PCD, it is still unclear how the upstream stress perception leads to the Ca2+ elevation and how the signal is further propagated to result in the onset of PCD. In this review article, we discuss recent advancements in the field, and compare the role of Ca2+ signaling in PCD in biotic and abiotic stresses. Moreover, we discuss the upstream and downstream components of Ca2+ signaling and its crosstalk with other signaling pathways in PCD. The review is expected to provide new insights into the role of Ca2+ signaling in PCD and to identify gaps for future research efforts.

scholarly journals RECENT ADVANCES IN SODIUM INTERCALATION POSITIVE ELECTRODE MATERIALS FOR SODIUM ION BATTERIES

2013 ◽  
Vol 06 (01) ◽  
pp. 1330001 ◽  
Author(s):  
JING XU ◽  
DAE HOE LEE ◽  
YING SHIRLEY MENG
Keyword(s):  
Electrode Materials ◽  
High Energy ◽  
Positive Electrode ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Significant Progress ◽  
Layered Oxides ◽  
Solid State Physics ◽  
The Past ◽  
Positive Electrode Materials

Significant progress has been achieved in the research on sodium intercalation compounds as positive electrode materials for Na-ion batteries. This paper presents an overview of the breakthroughs in the past decade for developing high energy and high power cathode materials. Two major classes, layered oxides and polyanion compounds, are covered. Their electrochemical performance and the related crystal structure, solid state physics and chemistry are summarized and compared.

scholarly journals Western Objections to the Islamic Concept of Gender Equality: A Critical Review

Fahm-i-Islam ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 55-70
Author(s):  
Dr Aurangzeb
Keyword(s):  
Gender Equality ◽  
Critical Review ◽  
Critical Analysis ◽  
View Point ◽  
Significant Progress ◽  
The West ◽  
The Past ◽  
Viable Solution ◽  
The World ◽  
Islamic View

Over the past several years, despite the constant evolution of the legislation the problem of gender equality in the West has been steadily increasing. What is the reason why there is no significant progress in solving gender equality issues in the West yet? Several reports and researches have pointed out to this problem. On the contrary, Islam provides a viable solution to this ever increasing problem; for Islam has a comprehensive yet simple view of gender equality. But the West, instead of understanding Islamic principles objectively, raises objections without a thorough study. However, the Western principle of gender equality has completely failed. In this article a critical analysis of the western gender equality and Islamic principles has been carried out. It also highlights Islamic view point of gender equality. The study argues that the contemporary gender equality problems and issues that have engulfed the world particularly the Western countries can be mitigated by employing the Islamic principles of gender equality

ANALYSIS OF THE INNOVATIVE DEVELOPMENT OF VIETNAM AND ITS ROLE IN INTERNATIONAL TRADE

2020 ◽  
Vol 3 (12) ◽  
pp. 147-150
Author(s):  
S. S. MURTUZALIEV ◽  
Keyword(s):  
Human Capital ◽  
International Trade ◽  
Innovative Development ◽  
Significant Progress ◽  
The Past ◽  
Global Innovation ◽  
Business Market

In this article, the author examines the level of innovative development of Vietnam and its impact on the course of international trade of this country, analyzes the statistics of the global innovation index of Vietnam and reviews Vietnam's cooperation with Russia and the EAEU. The relevance of this article is determined by the significant progress Vietnam has made over the past 20 years in the development of business, market, and technologies. Also, its global innovation index is growing steadily. However, problems with human capital and infrastructure continue to slow the pace of development of the country's economy.

Organic- or Inorganic-based Nanomaterials: Opportunities and Challenges in the Selection for Biomedicine

2021 ◽  
Vol 27 ◽  
Author(s):  
Ranjith Kankala
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Therapeutic Strategies ◽  
Lessons Learned ◽  
Clinical Translation ◽  
Significant Progress ◽  
Morphological Attributes ◽  
The Past ◽  
Selection For

: Since the inception of nanotechnology, several efforts have been dedicated to fabricating diverse nanodevices with exceptional performance. These innovative constructs have been applied in medicine due to their tailorable physicochemical properties (chemical composition, optical activity, spectra, and charge) and morphological attributes (size, shape, and surface area). Moreover, these versatile nanomedicines could promisingly offer better performance over the conventional therapeutic strategies. Broadly speaking, in terms of chemical composition, nanobiomaterials are classified into two predominant categories of organic and inorganic-based components. Despite their success and enormous versatile advancements in the past two decades, the significant progress towards clinical translation has been hampered by their corresponding intrinsic limitations. In this perspective, we give a brief overview of these organic- and inorganic-based materials, highlighting opportunities and challenges towards their utilization in medicine. Finally, we provide an interesting outlook in lessons learned and looking forward to developing these materials, emphasizing their scope towards clinical translation.

The Peptidyl Transferase Center: a Window to the Past

2021 ◽  
Author(s):  
Madhan R. Tirumalai ◽  
Mario Rivas ◽  
Quyen Tran ◽  
George E. Fox
Keyword(s):  
Genetic Code ◽  
21St Century ◽  
Origins Of Life ◽  
Current View ◽  
Significant Progress ◽  
Peptidyl Transferase ◽  
Peptidyl Transferase Center ◽  
The Road ◽  
The Past ◽  
History Of

In his 2001 article, “Translation: in retrospect and prospect,” the late Carl Woese made a prescient observation that “our current view of translation be reformulated to become an all-embracing perspective about which 21st century Biology can develop” (RNA 7:1055–1067, 2001, https://doi:10.1017/s1355838201010615 ). The quest to decipher the origins of life and the road to the genetic code are both inextricably linked with the history of the ribosome. After over 60 years of research, significant progress in our understanding of how ribosomes work has been made.

The Need for Culturally Responsive Mediation Practices to Enhance the Process and Outcomes of Mediation for Unmarried Fathers

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Razia Nordien-Lagardien ◽  
Blanche Pretorius ◽  
Susan Terblanche
Keyword(s):  
South Africa ◽  
Culturally Responsive ◽  
Customary Law ◽  
Significant Progress ◽  
Structured Interviews ◽  
Family Mediation ◽  
The Past ◽  
Explorative Study ◽  
Factors Influencing ◽  
Unmarried Fathers

The past decade has shown significant progress in family mediation services in South Africa, following the implementation of the amended Children’s Act of 2005, which has not fully considered issues relating to customary law and culture pertaining to mediation with unmarried fathers. A broader qualitative explorative study was undertaken to understand the experiences and perceptions of unmarried fathers, unmarried mothers and mediators regarding mediation. This article focuses on factors influencing the process and outcomes of mediation for unmarried fathers. Semi-structured interviews were conducted with a sample of seven unmarried fathers and eight mediators. Factors were identified that influence the process and outcomes of family mediation, of which culture, customary law and family dynamics are the focus of this article. Findings from Xhosa and Zulu participants in the study highlight the need for the inclusion of culturally responsive approaches to family mediation services by foregrounding issues relating to customary law, culture, and unmarried fathers.

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