The Casimir force between two neutral metallic plates is often considered conclusive evidence for the reality of electromagnetic zero-point fluctuations in ‘empty space’. However, it is not well known that the Casimir force can be derived from many different points of view. The purpose of this note is to supply a conceptually oriented introduction to a representative set of these different interpretations. The different accounts suggest that the Casimir effect reveals nothing conclusive about the nature of the vacuum.

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into (...) two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop. (shrink)

A fuzzy predictive fault-tolerant control scheme is proposed for a wide class of discrete-time nonlinear systems with uncertainties, interval time-varying delays, and partial actuator failures as well as unknown disturbances, in which the main opinions focus on the relevant theory of FPFTC based on Takagi-Sugeno fuzzy model description of these systems. The T-S fuzzy model represents the discrete-time nonlinear system in the form of the discrete uncertain time-varying delay state space, which is firstly constructed by a set of local linear (...) models and the nonlinear membership functions. The novel improved state space model can be further obtained by extending the output tracking error to the constructed model. Then the fuzzy predictive fault-tolerant control law based on this extended model is designed, which can increase more control degrees of freedom. Utilizing Lyapunov-Krasovskill theory, less conservative delay-range-dependent stable conditions in terms of linear matrix inequality constraints are given to ensure the asymptotically robust stability of closed-loop system. Meanwhile, the optimized cost function and H-infinity performance index are introduced to the stable conditions to guarantee the robust performance and antidisturbance capability. The simulation results on the temperature control of a strong nonlinear continuous stirred tank reactor show that the proposed control scheme is feasible and effective. (shrink)

Giải quyết biến đổi khí hậu và ô nhiễm môi trường đang và sẽ là thách thức lớn của nhân loại trong thế kỷ 21. Con người không còn nhiều thời gian để sửa chữa, phục hồi đưa hệ sinh thái môi trường (tự nhiên) trở về trạng thái an toàn. Trong khi các nỗ lực trong thời gian qua chưa thực sự hiệu quả thì COP26 mở ra cơ hội lớn để nhân loại tiến gần đến mục tiêu kiềm (...) chế nhiệt độ của trái đất không vượt quá 1.5 độ C. Mặc dù Việt Nam cùng với 146 quốc gia trên thế giới đã có cam kết mạnh mẽ nhất trong việc giảm phát thải vào năm 2050, tuy nhiên việc cụ thể hóa cam kết thông qua các giải pháp sáng tạo là rất quan trọng. Sử dụng (áp dụng, vận dụng) hệ sáng tạo 3D và nguyên lý bán dẫn giá trị, tác giả đề xuất hệ sinh thái “giải pháp trụ cột” cần thực hiện gồm có tăng cường thông tin, truyền thông, nghiên cứu khoa học về môi trường (biến đổi khí hậu, ô nhiễm môi trường...); xây dựng, chuyển đổi và nâng cao văn hóa và môi trường; đẩy mạnh phát triển kinh tế gia tăng phúc lợi; xây dựng (chuyển đổi) lớp doanh nhân có văn hóa, trách nhiệm môi trường; tăng cường mở rộng sự hợp tác quốc tế về mọi mặt đặc biệt là trong lĩnh vực kinh tế, truyền thông và khoa học; và thực thi các giải pháp nêu trên một cách kỷ luật. (shrink)

1. Amūnīyūs ibn Hirmiyās wa-atharuh fī falsafat al-Farābī = Ammonius son of Hermias and his influence on the philosophy of Al-Farabi--2. Simbilīlīkūs wa-atharuh fī mītāfīzīqā Ibn Sīnā = Simplicius and his influence on Avicenna's metaphysics.

PurposeThis study aimed to explore current developments and trends in the field of subjective well-being of older adults at a macro level and identify research hotspots.MethodsWe included reviews and articles on the SWB of older adults in the Web of Science Core Collection published from 2002 to 2021. We used CiteSpace to draw a knowledge map of the authors, institutions, countries, references, and keywords for visual analysis and used Microsoft Excel tables to count basic information details.ResultsA total of 354 papers (...) were included, and the number of papers published over the past two decades showed a pattern of growth. The core force of publications was primarily attributed to studies conducted in Europe, North America, Asia, and Oceania, which have relatively major issues of aging and good economic strength. However, links between states, institutions, and authors were relatively weak. Cluster analysis showed that the research field could be divided into eight topics: the application of social psychology in the study of the SWB of older adults, aging in older adults, health condition of older adults, achieving successful aging, interventions for SWB, age differences in SWB research, an economic perspective of SWB research and social support for older adults. Current research frontiers are socioeconomic status, community, intervention, participation, adjustment, validation, and personality.ConclusionThe results of the present study provided a comprehensive picture in the research field of SWB of older adults. It showed that the mechanism, especially the bidirectional effect, between the SWB of older adults and its influencing factors is still worthy of further exploration. More research on evidence-based and intervention strategies should be conducted in the future. (shrink)

How is the embryonic bipotential gonad regulated to produce either an ovary or a testis? In males, transient early activation of the Y chromosome Sry gene makes both germ cells and soma male. However, in females, available evidence suggests that the process of ovary sex determination may take place independently in the germline and somatic lineages. In addition, in contrast to testis, in ovary somatic cells, female‐to‐male gonadal sex reversal can occur at times throughout ovary development and maturation. We suggest (...) that a single gene pathway, likely hinging on the Foxl2 transcription factor, both initiates and maintains sex differentiation in somatic cells of the mammalian ovary. BioEssays 29: 15–25, 2007. Published 2006 Wiley Periodicals, Inc. (shrink)

Receptor‐mediated stimulation induces massive actin polymerization and cyto‐skeletal reorganization. The activity of a potent actin‐modulating protein, gelsolin, is regulated both by Ca2+ and polyphos‐phoinositides, and it may have a pivotal role in restructuring the actin cytoskeleton in response to agonist stimulation. Structure‐function analysis of gelsolin has (1) indicated that its NH2‐terminal half is primarily responsible for modulating actin filament length and polymerization; and (2) elucidated mechanisms by which Ca2+ and phospholipids may regulate such functions. Gelsolin is functionally and structurally similar (...) to villin, another Ca2+‐activated actin‐severing protein found in microvilli, suggesting that gelsolin may be a prototype of this family of actin‐modulating proteins. A molecular variant of gelsolin is secreted and may be involved in the clearance of actin filaments released during tissue damage. The two forms of gelsolin are encoded by a single gene, and distinct messages are derived by alternative message splicing. (shrink)

Commentators are divided on the interpretation of Metaphysics Z4 1029b13–22. For one thing, it is unclear whether the passage rejects a claim about the essence of surface, or about the essence of pale. It is usually thought that the claim is disavowed because it involves a circular definition. However, this is conjectural, since Aristotle does not explicitly say anything about circularity in the lines in question. I argue here for an alternative account, which reads the disputed lines as an extension (...) of the immediately preceding remarks. If correct, this also solves the problem as to just what Aristotle is denying. As will emerge, my story is helped by St. Thomas’ reading of lines 21–22, an account that has been curiously ignored in the recent literature. (shrink)

If James has a latent tuberculosis infection , he is at risk of developing active tuberculosis disease but he is not yet sick. LTBI is a liminal space between health and illness. Diagnosed with LTBI, James could be conceptualised as having a liminal body. Treatments for LTBI are available, but why would a person seek treatment for a disease he does not yet have? One thing is definite: James needs to be educated about the symptoms and severity of active tuberculosis (...) disease. (shrink)