232 research outputs found
Corporate governance and corporate social responsibility
Corporate governance and corporate social responsibilityIn recent decades, the field of corporate governance has increasingly recognized corporate social responsibility (CSR)âthe responsibility of firms to serve the interests of a broader set of stakeholders beyond their shareholdersâas an important part of the corporate goal. This dissertation includes three empirical studies that are designed to advance our knowledge about the role of corporate governance in shaping a firmâs CSR practices. Findings from these studies highlight two issues regarding the intersection between corporate governance and CSR. First, in some cases, corporate governance mechanisms that should stimulate socially responsible behavior merely play a symbolic role. As demonstrated in Chapter 2, NGO directors are more prevalent among firms with lower prior year CSR performance. Yet, their presence on boards is not associated with subsequent improvements in CSR performance. Second, institutions manifest their influence on the relationship between corporate governance mechanisms and CSR over time and across space. Chapter 3 explores the time dimension, revealing that transient institutional investors and quasi-indexers have become more important in reducing executive-to-worker pay dispersion as this issue becomes more salient since the 2007-2008 financial crisis. Chapter 4 focuses on the space dimension and shows that the effectiveness of board gender diversity policies in increasing women on boards varies across countries due to the different legislative, cultural, and economic institutions
Corporate social responsibility and NGO directors on boards
In the years 2009 to 2016, approximately 35% of Standard & Poorâs (S&P) 500 firms had at least one director with a professional background in private, not-for-profit organizations (NGO director). Yet research provides little guidance on what kind of firms are more likely to have NGO directors on their boards, neither do we know these directorsâ effects on firm strategic outcomes. Our study examines the above two questions in the context of corporate social responsibility (CSR), taking the lens of resource dependence theory. Results from an analysis of all firms included in the S&P 500 index between 2010 and 2016 show that the number of NGO directors serving on a firmâs board in a certain year is positively related to the extent to which the firm displays poor CSR performance in the prior year. We also find that NGO directors on boards are not associated with immediate improvements in CSR performance; rather, their positive influence on CSR performance takes hold after 3 years. Our findings suggest that whereas NGO directors may potentially be appointed to a firmâs board for legitimization reasons, these directors are associated with enhanced CSR performance in the long term
Isolation and characterization of a novel alphanodavirus
<p>Abstract</p> <p>Background</p> <p><it>Nodaviridae </it>is a family of non-enveloped isometric viruses with bipartite positive-sense RNA genomes. The <it>Nodaviridae </it>family consists of two genera: alpha- and beta-nodavirus. Alphanodaviruses usually infect insect cells. Some commercially available insect cell lines have been latently infected by Alphanodaviruses.</p> <p>Results</p> <p>A non-enveloped small virus of approximately 30 nm in diameter was discovered co-existing with a recombinant <it>Helicoverpa armigera </it>single nucleopolyhedrovirus (<it>Hear</it>NPV) in Hz-AM1 cells. Genome sequencing and phylogenetic assays indicate that this novel virus belongs to the genus of alphanodavirus in the family <it>Nodaviridae </it>and was designated HzNV. HzNV possesses a RNA genome that contains two segments. RNA1 is 3038 nt long and encodes a 110 kDa viral protein termed protein A. The 1404 nt long RNA2 encodes a 44 kDa protein, which exhibits a high homology with coat protein precursors of other alphanodaviruses. HzNV virions were located in the cytoplasm, in association with cytoplasmic membrane structures. The host susceptibility test demonstrated that HzNV was able to infect various cell lines ranging from insect cells to mammalian cells. However, only Hz-AM1 appeared to be fully permissive for HzNV, as the mature viral coat protein essential for HzNV particle formation was limited to Hz-AM1 cells.</p> <p>Conclusion</p> <p>A novel alphanodavirus, which is 30 nm in diameter and with a limited host range, was discovered in Hz-AM1 cells.</p
Recommended high performance telescope system design for the TianQin project
China is planning to construct a new space-borne gravitational-wave (GW)
observatory, the TianQin project, in which the spaceborne telescope is an
important component in laser interferometry. The telescope is aimed to transmit
laser beams between the spacecrafts for the measurement of the displacements
between proof-masses in long arms. The telescope should have ultra-small
wavefront deviation to minimize noise caused by pointing error, ultra-stable
structure to minimize optical path noise caused by temperature jitter,
ultra-high stray light suppression ability to eliminate background noise. In
this paper, we realize a telescope system design with ultra-stable structure as
well as ultra-low wavefront distortion for the space-based GW detection
mission. The design requirements demand extreme control of high image quality
and extraordinary stray light suppression ability. Based on the primary
aberration theory, the initial structure design of the mentioned four-mirror
optical system is explored. After optimization, the maximum RMS wavefront error
is less than lamda/300 over the full field of view (FOV), which meets the noise
budget on the telescope design. The stray light noise caused by the back
reflection of the telescope is also analyzed. The noise at the position of
optical bench is less than 10-10 of the transmitted power, satisfying the
requirements of space gravitational-wave detection. We believe that our design
can be a good candidate for TianQin project, and can also be a good guide for
the space telescope design in any other similar science project
Enhancement of the Antibacterial Activity of Silver Nanoparticles against Phytopathogenic Bacterium Ralstonia solanacearum
In this paper, the enhanced antibacterial activity of silver nanoparticles (AgNPs) against the phytopathogenic bacterium Ralstonia solanacearum after stabilization using selected surfactants (SDS, SDBS, TX-100, and Tween 80) was examined, in comparison with silver ion. Tween 80 was found to be the most preferable stabilizer of AgNPs due to the beneficial synergistic effects of the AgNPs and surfactant. However, all the surfactants nearly had no effects on the antibacterial activity of Ag+. In vitro, Tween 80-stabilized AgNPs showed the highest bactericidal activity against R. solanacearum. Further measurements using TEM, fluorescence microscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that though Ag+ and Tween 80-Ag+ induced high toxicity, Tween 80-stabilized AgNPs displayed most severe damage when in direct contact with cells, causing mechanistic injury to the cell membrane and strongly modifying and destructing the cellular proteins. Meanwhile, in vivo, the pot experiments data indicated that the control efficiency of Tween 80-stabilized AgNPs on tobacco bacterial wilt was 96.71%, 90.11%, and 84.21%, at 7 days, 14 days, and 21 days, respectively. Based on the results evidencing their advantageous low dosage requirements and strong antimicrobial activity, Tween 80-stabilized AgNPs are a promising antibacterial agent for use in alternative crop disease control approaches
Transport evidence of superlattice Dirac cones in graphene monolayer on twisted boron nitride substrate
Strong band engineering in two-dimensional (2D) materials can be achieved by
introducing moir\'e superlattices, leading to the emergence of various novel
quantum phases with promising potential for future applications. Presented
works to create moir\'e patterns have been focused on a twist embedded inside
channel materials or between channel and substrate. However, the effects of a
twist inside the substrate materials on the unaligned channel materials are
much less explored. In this work, we report the realization of superlattice
multi-Dirac cones with the coexistence of the main Dirac cone in a monolayer
graphene (MLG) on a ~0.14{\deg} twisted double-layer boron nitride (tBN)
substrate. Transport measurements reveal the emergence of three pairs of
superlattice Dirac points around the pristine Dirac cone, featuring multiple
metallic or insulating states surrounding the charge neutrality point (CNP).
Displacement field tunable and electron-hole asymmetric Fermi velocities are
indicated from temperature dependent measurements, along with the gapless
dispersion of superlattice Dirac cones. The experimental observation of
multiple Dirac cones in MLG/tBN heterostructure is supported by band structure
calculations employing periodic moir\'e potential. Our results unveil the
potential of using twisted substrate as a universal band engineering technique
for 2D materials regardless of lattice matching and crystal orientations, which
might pave the way for a new branch of twistronics.Comment: 13 pages, 4 figure
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Vehicle emission and atmospheric pollution in China: problems, progress, and prospects
China has been the largest vehicle market in the world since 2009. The stalemate between the rapid development of the vehicle industry and delayed vehicle emission control has become increasingly prominent. Vehicle emission has become a significant source of air pollution in Chinaâs cities. Understanding the current barriers in the vehicle industry is necessary for the development of effective and sustainable measures and policy to manage vehicle-induced air pollution. This review provides insight into the circumstances and causes of vehicle-induced air pollution and outlines recent progress in policy-makersâ long-term strategies and regulations. The development of an integrated mechanism of social participation, technical revolution, and regulatory innovation in vehicles, fuel, and roads is suggested to break the stalemate between air pollution and the automobile boom in China; the implications of this review extend to other countries facing the similar atmospheric pollution problems
Supercurrent, Multiple Andreev Reflections and Shapiro Steps in InAs Nanosheet Josephson Junctions
High-quality free-standing InAs nanosheets are emerging layered semiconductor
materials with potentials in designing planar Josephson junction devices for
novel physics studies due to their unique properties including strong
spin-orbit couplings, large Land\'e g-factors and the two dimensional nature.
Here, we report an experimental study of proximity induced superconductivity in
planar Josephson junction devices made from free-standing InAs nanosheets. The
nanosheets are grown by molecular beam epitaxy and the Josephson junction
devices are fabricated by directly contacting the nanosheets with
superconductor Al electrodes. The fabricated devices are explored by
low-temperature carrier transport measurements. The measurements show that the
devices exhibit a gate-tunable supercurrent, multiple Andreev reflections, and
a good quality superconductor-semiconductor interface. The superconducting
characteristics of the Josephson junctions are investigated at different
magnetic fields and temperatures, and are analyzed based on the
Bardeen-Cooper-Schrieffer (BCS) theory. The measurements of ac Josephson effect
are also conducted under microwave radiations with different radiation powers
and frequencies, and integer Shapiro steps are observed. Our work demonstrates
that InAs nanosheet based hybrid devices are desired systems for investigating
forefront physics, such as the two-dimensional topological superconductivity
Perpendicular in-plane negative magnetoresistance in ZrTe5
The unique band structure in topological materials frequently results in
unusual magneto-transport phenomena, one of which is in-plane longitudinal
negative magnetoresistance (NMR) with the magnetic field aligned parallel to
the electrical current direction. This NMR is widely considered as a hallmark
of chiral anomaly in topological materials. Here we report the observation of
in-plane NMR in the topological material ZrTe5 when the in-plane magnetic field
is both parallel and perpendicular to the current direction, revealing an
unusual case of quantum transport beyond the chiral anomaly. We find that a
general theoretical model, which considers the combined effect of Berry
curvature and orbital moment, can quantitatively explain this in-plane NMR. Our
results provide new insights into the understanding of in-plane NMR in
topological materials
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