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"Hall, D."
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Cosmic Explorer: A Next-Generation Ground-Based Gravitational-Wave Observatory
Cosmic Explorer is a concept for a new laser interferometric observatory in the United States to extend ground-based gravitational-wave astrophysics into the coming decades. Aiming to begin operation in the 2030s, Cosmic Explorer will extend current and future detector technologies to a 40 km interferometric baseline—ten times larger than the LIGO observatories. Operating as part of a global gravitational-wave observatory network, Cosmic Explorer will have a cosmological reach, detecting black holes and neutron stars back to the times of earliest star formation. It will observe nearby binary collisions with enough precision to reveal details of the dynamics of the ultradense matter in neutron stars and to test the general-relativistic model of black holes.
Journal Article
Observation of Dirac monopoles in a synthetic magnetic field
Dirac magnetic monopoles are created, directly imaged and identified in real space in the synthetic magnetic field produced by a spinor Bose–Einstein condensate.
Dirac action creates elusive monopoles
Ever since Dirac developed a comprehensive theory of magnetic monopoles in 1931, physicists have been eager to isolate these hypothetical particles featuring a north or south pole only. Although magnetic monopole analogues have been found in spin ices and other exotic systems, no Dirac monopoles have been observed directly within a medium described by a quantum field. But now David Hall and colleagues report the experimental observation of Dirac monopoles in the synthetic magnetic field produced by a spinor Bose–Einstein condensate. The authors obtain real-space images of monopoles at the termini of vortex lines within the condensate, providing evidence of the existence of Dirac monopoles. The creation and manipulation of Dirac monopoles in a controlled environment opens up a wide range of experimental and theoretical investigations.
Magnetic monopoles—particles that behave as isolated north or south magnetic poles—have been the subject of speculation since the first detailed observations of magnetism several hundred years ago
1
. Numerous theoretical investigations and hitherto unsuccessful experimental searches
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have followed Dirac’s 1931 development of a theory of monopoles consistent with both quantum mechanics and the gauge invariance of the electromagnetic field
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. The existence of even a single Dirac magnetic monopole would have far-reaching physical consequences, most famously explaining the quantization of electric charge
3
,
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. Although analogues of magnetic monopoles have been found in exotic spin ices
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,
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and other systems
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,
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,
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, there has been no direct experimental observation of Dirac monopoles within a medium described by a quantum field, such as superfluid helium-3 (refs
10
,
11
,
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,
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). Here we demonstrate the controlled creation
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of Dirac monopoles in the synthetic magnetic field produced by a spinor Bose–Einstein condensate. Monopoles are identified, in both experiments and matching numerical simulations, at the termini of vortex lines within the condensate. By directly imaging such a vortex line, the presence of a monopole may be discerned from the experimental data alone. These real-space images provide conclusive and long-awaited experimental evidence of the existence of Dirac monopoles. Our result provides an unprecedented opportunity to observe and manipulate these quantum mechanical entities in a controlled environment.
Journal Article
The global obesity pandemic: shaped by global drivers and local environments
The simultaneous increases in obesity in almost all countries seem to be driven mainly by changes in the global food system, which is producing more processed, affordable, and effectively marketed food than ever before. This passive overconsumption of energy leading to obesity is a predictable outcome of market economies predicated on consumption-based growth. The global food system drivers interact with local environmental factors to create a wide variation in obesity prevalence between populations. Within populations, the interactions between environmental and individual factors, including genetic makeup, explain variability in body size between individuals. However, even with this individual variation, the epidemic has predictable patterns in subpopulations. In low-income countries, obesity mostly affects middle-aged adults (especially women) from wealthy, urban environments; whereas in high-income countries it affects both sexes and all ages, but is disproportionately greater in disadvantaged groups. Unlike other major causes of preventable death and disability, such as tobacco use, injuries, and infectious diseases, there are no exemplar populations in which the obesity epidemic has been reversed by public health measures. This absence increases the urgency for evidence-creating policy action, with a priority on reduction of the supply-side drivers.
Journal Article
Accelerating antiviral drug discovery: lessons from COVID-19
During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in several therapeutics being discovered, approved and deployed in a 2-year time frame. This article summarizes the collective experience of several pharmaceutical companies and academic collaborations that were active in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral discovery. We outline our opinions and experiences on key stages in the small-molecule drug discovery process: target selection, medicinal chemistry, antiviral assays, animal efficacy and attempts to pre-empt resistance. We propose strategies that could accelerate future efforts and argue that a key bottleneck is the lack of quality chemical probes around understudied viral targets, which would serve as a starting point for drug discovery. Considering the small size of the viral proteome, comprehensively building an arsenal of probes for proteins in viruses of pandemic concern is a worthwhile and tractable challenge for the community.The COVID-19 pandemic spurred a wave of rapid and collaborative drug discovery efforts. This Perspective article summarizes scientific drivers and considerations behind such antiviral small-molecule discovery programmes and proposes strategies to accelerate future efforts.
Journal Article
تربية طفل متمرد : دليل يحفظ العقل لإيقاف السلوك السيئ
يوفر هذا الكتاب، سواء أظهر طفلك أنماطا متكررة من السلوك المندفع الغيرالملائم، لا أكثر، أم استوفى معايير التشخيص لاضطراب العناد الشارد، أساليب داعمة ومنورة، تم اختبارها، لتوجيهك وطفلك في الاتجاه الصحيح، وستتعلم كيفية منح طفلك الأساس والدعم اللذين يحتاجهما ليدرك إشارات التواصل الاجتماعي بدقة أكبر، ويمتلك السيطرة على اندفاعاته، فضلا عن تعزيز العلاقة بينكما، وتوفير الإمكانية لطفلك لتحقيق كل ما تعلم بقدرته على إنجازه.
BOOK
Revisiting the role of ABC transporters in multidrug-resistant cancer
Most patients who die of cancer have disseminated disease that has become resistant to multiple therapeutic modalities. Ample evidence suggests that the expression of ATP-binding cassette (ABC) transporters, especially the multidrug resistance protein 1 (MDR1, also known as P-glycoprotein or P-gp), which is encoded by ABC subfamily B member 1 (ABCB1), can confer resistance to cytotoxic and targeted chemotherapy. However, the development of MDR1 as a therapeutic target has been unsuccessful. At the time of its discovery, appropriate tools for the characterization and clinical development of MDR1 as a therapeutic target were lacking. Thirty years after the initial cloning and characterization of MDR1 and the implication of two additional ABC transporters, the multidrug resistance-associated protein 1 (MRP1; encoded by ABCC1)), and ABCG2, in multidrug resistance, interest in investigating these transporters as therapeutic targets has waned. However, with the emergence of new data and advanced techniques, we propose to re-evaluate whether these transporters play a clinical role in multidrug resistance. With this Opinion article, we present recent evidence indicating that it is time to revisit the investigation into the role of ABC transporters in efficient drug delivery in various cancer types and at the blood–brain barrier.
Journal Article