175 research outputs found
Investigation of the electronic properties of the recombination heterointerface in CGS/CIGS monolithic tandem solar cell
Spontaneous breaking of spatial and spin symmetry in spinor condensates
Parametric amplification of quantum fluctuations constitutes a fundamental
mechanism for spontaneous symmetry breaking. In our experiments, a spinor
condensate acts as a parametric amplifier of spin modes, resulting in a twofold
spontaneous breaking of spatial and spin symmetry in the amplified clouds. Our
experiments permit a precise analysis of the amplification in specific spatial
Bessel-like modes, allowing for the detailed understanding of the double
symmetry breaking. On resonances that create vortex-antivortex superpositions,
we show that the cylindrical spatial symmetry is spontaneously broken, but
phase squeezing prevents spin-symmetry breaking. If, however, nondegenerate
spin modes contribute to the amplification, quantum interferences lead to
spin-dependent density profiles and hence spontaneously-formed patterns in the
longitudinal magnetization.Comment: 5 pages, 4 figure
Parametric amplification of vacuum fluctuations in a spinor condensate
Parametric amplification of vacuum fluctuations is crucial in modern quantum
optics, enabling the creation of squeezing and entanglement. We demonstrate the
parametric amplification of vacuum fluctuations for matter waves using a spinor
F=2 Rb-87 condensate. Interatomic interactions lead to correlated pair creation
in the m_F= +/- 1 states from an initial unstable m_F=0 condensate, which acts
as a vacuum for m_F unequal 0. Although this pair creation from a pure m_F=0
condensate is ideally triggered by vacuum fluctuations, unavoidable spurious
initial m_F= +/- 1 atoms induce a classical seed which may become the dominant
triggering mechanism. We show that pair creation is insensitive to a classical
seed for sufficiently large magnetic fields, demonstrating the dominant role of
vacuum fluctuations. The presented system thus provides a direct path towards
the generation of non-classical states of matter on the basis of spinor
condensates.Comment: 5 pages, 4 figure
Mirroring the Zeitgeist: An Analysis of CSR Policies in the UK’s Food, Soft Drink and Packaging Industries
Purpose
The purpose of this paper is to explore changes in corporate social responsibility (CSR) policies in food, soft drinks and packaging industries to capture changes in CSR implementation given increased environmental activism. The paper takes an exploratory approach in reviewing CSR policy changes to explore to what extent companies change CSR policies with increased environmentalism.
Design/methodology/approach
A comparative website analysis was used to analyse CSR policies of companies in the food, soft drinks and packaging industries in the UK. The companies were selected for the analysis based on their annual turnover and 23 companies were analysed (seven for the soft drinks industry, eight for the food industry and eight for packaging industry). Five interviews were conducted with packaging and retail professionals, and the findings were analysed by using thematic analysis, which captured trends in responses.
Findings
The findings show that companies are implementing and communicating CSR policies heavily focussed on reducing the environmental impact of their work and matching social debates on human rights, with which traditional CSR policies (corporate governance, supporting local communities and consultation with stakeholders) are fading away. Instead, companies have shifted attention towards the gender pay gap, modern slavery and extensive environmentalism. The interviews with packaging professionals and CSR managers from the retail industry show that the packaging industry designs CSR policies in line with requests from supermarkets, which are, in turn, influenced by consumer activism.
Practical implications
This paper shows the circular relationship between media coverage, consumer activism, which comes as a result, and the impact and changes this brings to the industry. To avoid reputation damage, companies should closely follow media debates to pre-empty consumer criticism and activism.
Social implications
The findings show that companies are “mirroring the zeitgast” and going with trends to meet consumer expectations, which brings into question the sincerity of CSR policies and revives the criticism of capitalism and raises a question whether CSR is used by companies as a smokescreen that on the outset makes a difference to the society but keeps status quo intact.
Originality/value
The paper provides an insight into CSR implementation of three industries that faced heavy criticism from campaigners and the general public for their environmental impact. The paper shows how the CSR policy shifted to match this expectation and thus provides a good ground for studying the evolution of CSR using a case study from three selected industries
Multi-resonant spinor dynamics in a Bose-Einstein condensate
We analyze the spinor dynamics of a Rb-87 F=2 condensate initially prepared
in the m_F=0 Zeeman sublevel. We show that this dynamics, characterized by the
creation of correlated atomic pairs in m_F=+/-1, presents an intriguing
multi-resonant magnetic field dependence induced by the trap inhomogeneity.
This dependence is directly linked to the most unstable Bogoliubov spin
excitations of the initial m_F = 0 condensate, showing that, in general, even a
qualitative understanding of the pair creation efficiency in a spinor
condensate requires a careful consideration of the confinement.Comment: 5 pages, 4 figure
Electroluminescence imaging of PV devices: Advanced vignetting calibration
IEEE Electroluminescence (EL) imaging is affected by off-axis illumination together with sensor and lens imperfections. The images’ spatial intensity distribution is mainly determined by the vignetting effect. For quantitative EL imaging, its correction is essential. If neglected, intensities can vary significantly (>50%) across the image. This paper introduces and tests four vignetting measurement methods. The quantitative comparison of different methods shows that vignetting should be characterized preferably in plane by the source of the same type as the photovoltaic (PV) device to be tested. A direct PV-based measurement in short distance with spatial inhomogeneity correction is proposed for general-purpose vignetting characterization. For precise vignetting characterization, vignetting-object separation using pattern recognition is proposed. The use of non-PV light sources for vignetting characterization can cause vignetting overcorrection and can even decrease the quality of the vignetting-corrected images
Polymorphism of alpha-1-antitrypsin in hematological malignancies
Alpha-1-antitrypsin (AAT) or serine protease inhibitor A1 (SERPINA1) is an important serine protease inhibitor in humans. The main physiological role of AAT is to inhibit neutrophil elastase (NE) released from triggered neutrophils, with an additional lesser role in the defense against damage inflicted by other serine proteases, such as cathepsin G and proteinase 3. Although there is a reported association between AAT polymorphism and different types of cancer, this association with hematological malignancies (HM) is, as yet, unknown. We identified AAT phenotypes by isoelectric focusing (in the pH 4.2-4.9 range) in 151 serum samples from patients with HM (Hodgkins lymphomas, non-Hodgkins lymphomas and malignant monoclonal gammopathies). Healthy blood-donors constituted the control group (n = 272). The evaluated population of patients as well as the control group, were at Hardy-Weinberg equilibrium for the AAT gene (χ2 = 4.42, d.f.11, p = 0.96 and χ2 = 4.71, d.f.11, p = 0.97, respectively). There was no difference in the frequency of deficient AAT alleles (Pi Z and Pi S) between patients and control. However, we found a significantly higher frequency of PiM1M1 homozygote and PiM1 allele in HM patients than in control (for phenotype: f = 0.5166 and 0.4118 respectively, p = 0.037; for allele: f = 0.7020 and 0.6360 respectively, p = 0.05). In addition, PiM homozygotes in HM-patients were more numerous than in controls (59% and 48%, respectively, p = 0.044). PiM1 alleles and PiM1 homozygotes are both associated with hematological malignancies, although this is considered a functionally normal AAT variant
Management of infections pre- and post-liver transplantation: Report of an AISF consensus conference
The burden of infectious diseases both before and after liver transplantation is clearly attributable to the dysfunction of defensive mechanisms of the host, both as a result of cirrhosis, as well as the use of immunosuppressive agents. The present document represents the recommendations of an expert panel commended by the Italian Association for the Study of the Liver (AISF), on the prevention and management of infectious complications excluding hepatitis B, D, C, and HIV in the setting of liver transplantation. Due to a decreased response to vaccinations in cirrhosis as well as within the first six months after transplantation, the best timing for immunization is likely before transplant and early in the course of disease. Before transplantation, a vaccination panel including inactivated as well as live attenuated vaccines is recommended, while oral polio vaccine, Calmette-Guerin's bacillus, and Smallpox are contraindicated, whereas after transplantation, live attenuated vaccines are contraindicated. Before transplant, screening protocols should be divided into different levels according to the likelihood of infection, in order to reduce costs for the National Health Service. Recommended preoperative and postoperative prophylaxis varies according to the pathologic agent to which it is directed (bacterial vs. viral vs. fungal). Timing after transplantation greatly determines the most likely agent involved in post-transplant infections, and specific high-risk categories of patients have been identified that warrant closer surveillance. Clearly, specifically targeted treatment protocols are needed upon diagnosis of infections in both the pre- as well as the post-transplant scenarios, not without considering local microbiology and resistance patterns
Critical Exponents of the N-vector model
Recently the series for two RG functions (corresponding to the anomalous
dimensions of the fields phi and phi^2) of the 3D phi^4 field theory have been
extended to next order (seven loops) by Murray and Nickel. We examine here the
influence of these additional terms on the estimates of critical exponents of
the N-vector model, using some new ideas in the context of the Borel summation
techniques. The estimates have slightly changed, but remain within errors of
the previous evaluation. Exponents like eta (related to the field anomalous
dimension), which were poorly determined in the previous evaluation of Le
Guillou--Zinn-Justin, have seen their apparent errors significantly decrease.
More importantly, perhaps, summation errors are better determined. The change
in exponents affects the recently determined ratios of amplitudes and we report
the corresponding new values. Finally, because an error has been discovered in
the last order of the published epsilon=4-d expansions (order epsilon^5), we
have also reanalyzed the determination of exponents from the epsilon-expansion.
The conclusion is that the general agreement between epsilon-expansion and 3D
series has improved with respect to Le Guillou--Zinn-Justin.Comment: TeX Files, 27 pages +2 figures; Some values are changed; references
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