2,955 research outputs found

    Standardization and the Impacts of Voluntary Program Participation: Evidence from Environmental Auditing

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    We explore how limits to our insight about the underlying decision-making structure of firms may affect the conclusions we draw about the likely impacts of participation in voluntary environmental programs. We develop a theoretical model to examine the conditions under which a multi-facility firm chooses to employ a standardized adoption policy for a voluntary program. We test this model empirically using a firm-level dataset on the adoption of a voluntary environmental auditing program and find that, consistent with the theoretical model, a standardized auditing outcome is less likely among firms with more heterogeneous portfolios of facilities. We also examine the effect of environmental auditing on facility compliance using both firm-level and facility-level controls. We find that the estimated effect depends on whether or not measures that proxy for firm incentives for standardization are included in the analysis. These findings suggest caution in drawing conclusions on the effectiveness of voluntary programs in improving compliance based on analyses that assume standardization on the part of the firm

    Continuously tunable modulation scheme for precision control of optical cavities with variable detuning

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    We present a scheme for locking optical cavities with arbitrary detuning by many linewidths from resonance using an electro-optic modulator that can provide arbitrary ratios of amplitude-to-phase modulation. We demonstrate our scheme on a Fabry–Perot cavity, and show that a well-behaved linear error signal can be obtained by demodulating the reflected light from a cavity that is detuned by several linewidths.National Science Foundation (U.S.) (PHY-0757058

    Making NSCLC Crystal Clear:How Kinase Structures Revolutionized Lung Cancer Treatment

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    The parallel advances of different scientific fields provide a contemporary scenario where collaboration is not a differential, but actually a requirement. In this context, crystallography has had a major contribution on the medical sciences, providing a “face” for targets of diseases that previously were known solely by name or sequence. Worldwide, cancer still leads the number of annual deaths, with 9.6 million associated deaths, with a major contribution from lung cancer and its 1.7 million deaths. Since the relationship between cancer and kinases was unraveled, these proteins have been extensively explored and became associated with drugs that later attained blockbuster status. Crystallographic structures of kinases related to lung cancer and their developed and marketed drugs provided insight on their conformation in the absence or presence of small molecules. Notwithstanding, these structures were also of service once the initially highly successful drugs started to lose their effectiveness in the emergence of mutations. This review focuses on a subclassification of lung cancer, non-small cell lung cancer (NSCLC), and major oncogenic driver mutations in kinases, and how crystallographic structures can be used, not only to provide awareness of the function and inhibition of these mutations, but also how these structures can be used in further computational studies aiming at addressing these novel mutations in the field of personalized medicine

    Properties and dynamics of meron topological spin textures in the two-dimensional magnet CrCl3

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    Merons are nontrivial topological spin textures highly relevant for many phenomena in solid state physics. Despite their importance, direct observation of such vortex quasiparticles is scarce and has been limited to a few complex materials. Here we show the emergence of merons and antimerons in recently discovered two-dimensional (2D) CrCl3 at zero magnetic field. We show their entire evolution from pair creation, their diffusion over metastable domain walls, and collision leading to large magnetic monodomains. Both quasiparticles are stabilized spontaneously during cooling at regions where in-plane magnetic frustration takes place. Their dynamics is determined by the interplay between the strong in-plane dipolar interactions and the weak out-of-plane magnetic anisotropy stabilising a vortex core within a radius of 8-10 nm. Our results push the boundary to what is currently known about non-trivial spin structures in 2D magnets and open exciting opportunities to control magnetic domains via topological quasiparticles.Comment: Nature Communications 12, 185 (2021). Editors' Highlights sectio

    Livestock-Associated Methicillin-Resistant Staphylococcus aureus From Animals and Animal Products in the UK

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    [EN] Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an emerging problem in many parts of the world. Although animal-adapted LA-MRSA has been known for many years, recent reports suggest a possible increasing trend in the zoonotic transmission of LA-MRSA in Europe. Since its emergence in the early 2000¿s, several investigations have indicated that persons in prolonged, repeated contact with affected livestock are at a higher risk of becoming colonized with LA-MRSA. LA-MRSA monitoring in livestock is voluntary under current EU legislation, and not all member states, including the UK, participate. UK LA-MRSA isolates have been detected through scanning surveillance, where samples are submitted from clinically diseased livestock for diagnostic investigation, and research studies. Surveys conducted on retail beef, pig and poultry meat on sale in the UK have also detected LA-MRSA. Taken together these results suggest that LA-MRSA is present in the UK, possibly at low prevalence level, as suggested by available evidence. In this review, we examine the data available from UK livestock and animal products, and make recommendations for future. We also review the findings from whole genome sequencing (WGS) of the possible lineage of some UK livestock isolates.We are grateful to the Veterinary Medicines Directorate in the UK for funding this work through VMD0533. FM-J contributed during a sabbatical to the APHA with a grant from Consellería de Educación y Ciencia of Generalitat Valenciana (BEST/2017/050). CM contributed during a sabbatical to the APHA which was supported by a Lecturer research grant from the Santander bank (programme XIII Convocatoria de ayudas a la movilidad investigadora CEU-Banco Santander).Anjum, MF.; Marco-Jiménez, F.; Duncan, D.; Marin-Orenga, C.; Smith, RP.; Evans, SJ. (2019). Livestock-Associated Methicillin-Resistant Staphylococcus aureus From Animals and Animal Products in the UK. Frontiers in Microbiology. 10:1-7. https://doi.org/10.3389/fmicb.2019.02136S171

    Breaking through the Mermin-Wagner limit in 2D van der Waals magnets

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    The Mermin-Wagner theorem states that long-range magnetic order does not exist in one- (1D) or two-dimensional (2D) isotropic magnets with short-ranged interactions. Here we show that in finite-size 2D van der Waals magnets typically found in lab setups (within millimetres), short-range interactions can be large enough to allow the stabilisation of magnetic order at finite temperatures without any magnetic anisotropy. We demonstrate that magnetic ordering can be created in 2D flakes independent of the lattice symmetry due to the intrinsic nature of the spin exchange interactions and finite-size effects. Surprisingly we find that the crossover temperature, where the intrinsic magnetisation changes from superparamagnetic to a completely disordered paramagnetic regime, is weakly dependent on the system length, requiring giant sizes (e.g., of the order of the observable universe ~ 1026 m) to observe the vanishing of the magnetic order as expected from the Mermin-Wagner theorem. Our findings indicate exchange interactions as the main ingredient for 2D magnetism

    Breaking through the Mermin-Wagner limit in 2D van der Waals magnets

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    The Mermin-Wagner theorem states that long-range magnetic order does not exist in one- or two-dimensional (2D) isotropic magnets with short-ranged interactions. The theorem has been a milestone in magnetism and has been driving the research of recently discovered 2D van der Waals (vdW) magnetic materials from fundamentals up to potential applications. In such systems, the existence of magnetic ordering is typically attributed to the presence of a significant magnetic anisotropy, which is known to introduce a spin-wave gap and circumvent the core assumption of the theorem. Here we show that in finite-size 2D vdW magnets typically found in lab setups (e.g., within millimetres), short-range interactions can be large enough to allow the stabilisation of magnetic order at finite temperatures without any magnetic anisotropy for practical implementations. We demonstrate that magnetic ordering can be created in flakes of 2D materials independent of the lattice symmetry due to the intrinsic nature of the spin exchange interactions and finite-size effects in two-dimensions. Surprisingly we find that the crossover temperature, where the intrinsic magnetisation changes from superparamagnetic to a completely disordered paramagnetic regime, is weakly dependent on the system length, requiring giant sizes (e.g., of the order of the observable universe ~1026^{26} m) in order to observe the vanishing of the magnetic order at cryogenic temperatures as expected from the Mermin-Wagner theorem. Our findings indicate exchange interactions as the main driving force behind the stabilisation of short-range order in 2D magnetism and broaden the horizons of possibilities for exploration of compounds with low anisotropy at an atomically thin level

    How Is Chimpanzee Self-Control Influenced by Social Setting?

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    Self-control is often required in natural situations involving interactions with other individuals, and personal self-control can be compromised if other individuals act impulsively. In this study, we tested self-control in pairs of chimpanzees in a variety of settings where at least one chimpanzee of each pair performed an established test for self-control in which candies accumulated one at time as long as the chimpanzee did not eat any of them. When tested alone, some chimpanzees exhibited greater self-control as compared to when tested alongside a chimpanzee that independently performed the same type of test. However, when the nonfocal animal freely consumed rewards while the focal chimpanzee performed the accumulation task, the self-control of some focal chimpanzees was elevated as compared to when working alone. Finally, when the focal and nonfocal animals worked jointly on the same test and the number of rewards accumulated was dependent on both animals’ continued ability to inhibit eating the items, chimpanzees performed the same when housed together or in adjacent enclosures. On the whole, the effects of social setting were modest, but these results may relate to the literature on vicarious depletion of self-control, and they present interesting avenues for future research
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