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Increasing the number of quantum bits while preserving precise control of their quantum electronic properties is a significant challenge in materials design for the development of semiconductor quantum computing devices. Semiconductor heterostructures can host multiple quantum dots that are electrostatically defined by voltages applied to an array of metallic nanoelectrodes. The structural distortion of multiple-quantum-dot devices due to elastic stress associated with the electrodes has been difficult to predict because of the large micrometer-scale overall sizes of the devices, the complex spatial arrangement of the electrodes, and the sensitive dependence of the magnitude and spatial variation of the stress on processing conditions. Synchrotron X-ray nanobeam Bragg diffraction studies of a GaAs/AlGaAs heterostructure reveal the magnitude and nanoscale variation of these distortions. Investigations of individual linear electrodes reveal lattice tilts consistent with a 28-MPa compressive residual stress in the electrodes. The angular magnitude of the tilts varies by up to 20% over distances of less than 200 nm along the length of the electrodes, consistent with heterogeneity in the metal residual stress. A similar variation of the crystal tilt is observed in multiple-quantum-dot devices, due to a combination of the variation of the stress and the complex electrode arrangement. The heterogeneity in particular can lead to significant challenges in the scaling of multiple-quantum-dot devices due to differences between the charging energies of dots and uncertainty in the potential energy landscape. Alternatively, if incorporated in design, stress presents a new degree of freedom in device fabrication.
In this paper we examine the role of weak magnetic fields in breaking Kelvin’s circulation theorem and in vortex breakup in two-dimensional magnetohydrodynamics for the physically important case of a fluid with low magnetic Prandtl number (low
). We consider three canonical inviscid solutions for the purely hydrodynamical problem, namely a Gaussian vortex, a circular vortex patch and an elliptical vortex patch. We examine how magnetic fields lead to an initial loss of circulation
and attempt to derive scaling laws for the loss of circulation as a function of field strength and diffusion as measured by two non-dimensional parameters. We show that for all cases the loss of circulation depends on the integrated effects of the Lorentz force, with the patch cases leading to significantly greater circulation loss. For the case of the elliptical vortex, the loss of circulation depends on the total area swept out by the rotating vortex, and so this leads to more efficient circulation loss than for a circular vortex.
Hyperbolic polariton modes are highly appealing for a broad range of applications in nanophotonics, including surfaced enhanced sensing, sub-diffractional imaging, and reconfigurable metasurfaces. Here we show that attenuated total reflectance (ATR) micro-spectroscopy using standard spectroscopic tools can launch hyperbolic polaritons in a Kretschmann–Raether configuration. We measure multiple hyperbolic and dielectric modes within the naturally hyperbolic material hexagonal boron nitride as a function of different isotopic enrichments and flake thickness. This overcomes the technical challenges of measurement approaches based on nanostructuring, or scattering scanning near-field optical microscopy. Ultimately, our ATR approach allows us to compare the optical properties of small-scale materials prepared by different techniques systematically.
This work is part of the interlaboratory collaboration to study the stability of organic solar cells containing PCDTBT polymer as a donor material. The varieties of the OPV devices with different device architectures, electrode materials, encapsulation, and device dimensions were prepared by seven research laboratories. Sets of identical devices were aged according to four different protocols: shelf lifetime, laboratory weathering under simulated illumination at ambient temperature, laboratory weathering under simulated illumination, and elevated temperature (65 °C) and daylight outdoor weathering under sunlight. The results generated in this study allow us to outline several general conclusions related to PCDTBT-based bulk heterojunction (BHJ) solar cells. The results herein reported can be considered as practical guidance for the realization of stabilization approaches in BHJ solar cells containing PCDTBT.
In this review article, we discuss selected developments regarding the role of the equation of state in simulations of core-collapse supernovae. There are no first-principle calculations of the state of matter under supernova conditions since a wide range of conditions is covered, in terms of density, temperature, and isospin asymmetry. Instead, model equation of state are commonly employed in supernova studies. These can be divided into regimes with intrinsically different degrees of freedom: heavy nuclei at low temperatures, inhomogeneous nuclear matter where light and heavy nuclei coexist together with unbound nucleons, and the transition to homogeneous matter at high densities and temperatures. In this article, we discuss each of these phases with particular view on their role in supernova simulations.
The diagnosis and treatment of depression are complicated by the presence of a serious medical illness, such as cancer. The role of inflammation in the pathophysiology of depression remains unknown; however, the symptom cluster of sickness behavior is more clearly related to inflammation. Symptom clusters may provide the specificity needed to improve treatment outcomes. The purpose of this study is to use confirmatory factor analysis to examine the construct of sickness behavior in patients with advanced cancer using the Beck Depression Inventory–II (BDI–II).
Patients (N = 167) were recruited from chemotherapy clinics and the Department of Psychiatry at Memorial Sloan Kettering Cancer Center. Symptoms were a priori delineated using the factor labels sickness behavior and negative affectivity (two-factor model), and affective, cognitive, and sickness behavior (three-factor model). These data were also fit for a more traditional model using affective, cognitive, and somatic factors.
The mean total BDI–II score was 14.74 (SD = 8.52; range = 1–46). Fit statistics for all models were good, but the novel three-factor model with sickness behavior provided the best fit: χ2(186) = 273.624; p < 0.001; root-mean-square error of approximation = 0.053; comparative fit index = 0.949.
Significance of results:
Both the two- and three-factor models provide support for the unique construct of sickness behavior in patients with advanced cancer. High factor correlations with the BDI–II and other measures of distress were observed, which raises questions about theoretically distinct, but related, constructs.
Subjective cognitive decline (SCD), the potentially earliest notable manifestation of preclinical Alzheimer's disease and other dementias, was consistently associated with lower quality of life in cross-sectional studies. The aim of this study was to investigate whether such an association persists longitudinally – particularly with health-related quality of life (HRQoL) in older individuals without cognitive impairment.
Data were derived from follow-up 2–6 of the prospective Germany Study on Ageing, Cognition and Dementia in Primary Care (AgeCoDe) covering a total six-year observation period. We used linear mixed effects models to estimate the effect of SCD on HRQoL measured by the EQ-5D visual analogue scale (EQ VAS).
Of 1,387 cognitively unimpaired individuals aged 82.2 years (SD = 3.2) on average, 702 (50.6%) reported SCD and 230 (16.6%) with SCD-related concerns. Effect estimates of the linear mixed effects models revealed lower HRQoL in individuals with SCD (unadjusted: –3.7 points on the EQ VAS, 95%CI = –5.3 to –2.1; SE = 0.8; p < 0.001; adjusted: –2.9 points, 95%CI = –3.9 to –1.9; SE = 0.5; p < 0.001) than in individuals without SCD. The effect was most pronounced in SCD with related concerns (unadjusted: –5.4, 95%CI = –7.6 to –3.2; SE = 1.1; p < 0.001; adjusted: –4.3, 95%CI = –5.8 to –2.9, SE = 0.7; p < 0.001).
SCD constitutes a serious issue to older cognitively unimpaired individuals that is depicted in persisting lower levels of HRQoL beyond depressive symptoms and functional impairment. Therefore, SCD should be taken seriously in clinical practice.
The current study investigates potential pathways from socio-economic status (SES) to BMI in the adult population, considering psychological domains of eating behaviour (restrained eating, uncontrolled eating, emotional eating) as potential mediators stratified for sex.
Data were derived from the population-based cross-sectional LIFE-Adult-Study. Parallel-mediation models were conducted to obtain the total, direct and indirect effects of psychological eating behaviour domains on the association between SES and BMI for men and for women.
We studied 5935 participants aged 18 to 79 years.
Uncontrolled eating mediated the association between SES and BMI in men only and restrained eating in both men and women. Emotional eating did not act as mediator in this relationship. The total effect of eating behaviour domains on the association between SES and BMI was estimated as β=−0·03 (se 0·02; 95 % CI −0·062, −0·003) in men and β=−0·18 (se 0·02; 95 % CI −0·217, −0·138) in women.
Our findings do not indicate a strong overall mediation effect of the eating behaviour domains restrained eating, uncontrolled eating and emotional eating on the association between SES and BMI. Further research on other pathways of this association is strongly recommended. Importantly, our findings indicate that, independent from one’s social position, focusing on psychological aspects in weight reduction might be a promising approach.
Parasites of the genera Plasmodium and Haemoproteus (Apicomplexa: Haemosporida) are a diverse group of pathogens that infect birds nearly worldwide. Despite their ubiquity, the ecological and evolutionary factors that shape the diversity and distribution of these protozoan parasites among avian communities and geographic regions are poorly understood. Based on a survey throughout the Neotropics of the haemosporidian parasites infecting manakins (Pipridae), a family of Passerine birds endemic to this region, we asked whether host relatedness, ecological similarity and geographic proximity structure parasite turnover between manakin species and local manakin assemblages. We used molecular methods to screen 1343 individuals of 30 manakin species for the presence of parasites. We found no significant correlations between manakin parasite lineage turnover and both manakin species turnover and geographic distance. Climate differences, species turnover in the larger bird community and parasite lineage turnover in non-manakin hosts did not correlate with manakin parasite lineage turnover. We also found no evidence that manakin parasite lineage turnover among host species correlates with range overlap and genetic divergence among hosts. Our analyses indicate that host switching (turnover among host species) and dispersal (turnover among locations) of haemosporidian parasites in manakins are not constrained at this scale.
To evaluate the agreement between the current National Healthcare Safety Network (NHSN) definition for ventriculitis and others found in the literature among patients with an external ventricular drain (EVD)
Retrospective cohort study from January 2009 to December 2014
Neurology and neurosurgery intensive care unit of a large tertiary-care center
Patients with an EVD were included. Patients with an infection prior to EVD placement or a permanent ventricular shunt were excluded.
We reviewed the charts of patients with positive cerebrospinal fluid (CSF) cultures and/or abnormal CSF results while they had an EVD in place and applied various ventriculitis definitions.
We identified 48 patients with a total of 52 cases of ventriculitis (41 CSF culture-positive cases and 11 cases based on abnormal CSF test results) using the NHSN definition. The most common organisms causing ventriculitis were gram-positive commensals (79.2%); however, 45% showed growth of only 1 colony on 1 piece of media. Approximately 60% of the ventriculitis cases by the NHSN definition met the Honda criteria, approximately 56% met the Gozal criteria, and 23% met Citerio’s definition. Cases defined using Honda versus Gozal definitions had a moderate agreement (κ=0.528; P<.05) whereas comparisons of Honda versus Citerio definitions (κ=0.338; P<.05) and Citerio versus Gozal definitions (κ=0.384; P<.05) had only fair agreements.
The agreement between published ventriculostomy-associated infection (VAI) definitions in this cohort was moderate to fair. A VAI surveillance definition that better defines contaminants is needed for more homogenous application of surveillance definitions between institutions and better comparison of rates.
Most of the previous studies attempted to disentangle the relationship between disability and depressive symptoms were limited to observation periods of only few years. Moreover, evidence is missing regarding the complex co-occurrence of disability and depressive symptoms in old age in Germany. In order to close the research gap, we aimed at disentangling the complex co-occurrence of disability and depressive symptoms in old age in Germany over a longer time frame.
Based on data from a representative survey of the German general population aged 75 years and older, the course of disability as well as depressive symptoms was observed every 1.5 years over six waves. While disability was quantified by the Lawton and Brody Instrumental Activities of Daily Living scale, the Geriatric Depression Scale was used to measure depressive symptoms. Taking into account the complex co-occurrence of depressive symptoms and disability, a panel vector autoregressive model was used. By taking the first differences, unobserved heterogeneity was taken into account.
In the total sample and in both sexes, we revealed a robust positive association between an initial change in depressive symptoms and subsequent changes in disability. No robust association between an initial change in disability and a subsequent change in depressive symptoms was detected.
Our findings highlight the importance of changes in depressive symptoms for future changes in disability in old age.
In accelerator systems, beam lines are generally equipped with diagnostic elements, such as Faraday cups and beam profile monitors (BPM), to optimize beam transport. These diagnostic elements, or at least commercial ones, are designed to only work with continuous beams, and their typical maximum sensitivity is about few tens of pA. Thus, in the case of diagnosis of rare isotope beams in accelerator mass spectrometry (AMS), Faraday cups and BPMs are not suitable on the high-energy side of the tandem accelerator, after energy-mass-charge analysis. For example, in 14C AMS, even for a modern sample, the expected counting rate is a few tens of Hz; in these conditions, a commercial BPM cannot be used. On the other hand, checking the shape and the position of the rare isotope beam hitting the detector can be important in order to better identify signals in the detector itself, thus also helping in reducing the measurement background.
This paper presents a prototype BPM especially designed for low-intensity beams. The BPM is based on a multiwire proportional chamber characterized by 2 grids of anode wires, oriented perpendicular to each other in order to measure both the x and the y coordinates of the particle impact point. Details about the design and the electronics of the device are given, and the first test measurements are discussed.
On 5 February 2016, the National Oceanic and Atmospheric Administration (hereinafter, NOAA),within the United States (hereinafter, US) Department of Commerce, published a Proposed Rule to create a seafood traceability programme. The programme intends to combat illegal, unreported and unregulated (hereinafter, IUU) fishing, prevent fraudulent trade and to serve as the contribution of the US to the global action to combat IUU fishing, along the lines of other similar regulatory frameworks, such as the EU's extensive regulationon IUU fishing. However, despite the legitimate objectives of the measure, it is imperative that regulators take into account the potential consequences for international trade when designing such programmes.
The use of a catalyst is required to synthesize poly(D,L-lactide) (PLA) and tin (II) 2-ethylhexanoate could be highlighted among them. However, this kind of catalysts can produce bio-dangerous compounds limiting the PLA in medical applications, therefore there is a need to investigate novel bio-safe catalysts. Taking into account this problem, this communication reports the use of micro- and nano-ZnO particles as catalysts for the microwave-assisted polymerization of D,L-lactide. By microwave heating a high monomer conversion (higher than 95%) was achieved in a relatively short reaction time (3 hours). Morphology/size and concentration of ZnO particles presented a strong effect on the production of PLA, star-like microparticles leaded to conversion ca. 25%, well below to the values achieved with the nanoparticles. Furthermore, the formation of a ZnO-PLA hybrid was evidenced by spectroscopic and thermal characterization techniques. The methodology herein developed represents a new pathway for the green synthesis of PLA.
Introduction: The diagnosis of trisomy 21 in children has been associated with failed extubation after CHD surgery. Dexmedetomidine may be a useful agent to improve postoperative outcomes in these patients, such as ventilator time, ICU length of stay, or hospital length of stay. Materials and methods: The Pediatric Health Information System database was queried from January, 2008 to December, 2010 for patients with trisomy 21 who underwent CHD surgery. Patients who received dexmedetomidine were matched to patients who did not by propensity score. The primary outcome was ventilator days charged, and secondary outcomes included ICU and hospital length of stay. Results: A total of 1088 patients (544 matched pairs) met inclusion criteria. Patient characteristics were similar, with the exception of more patients in the dexmedetomidine group undergoing repair of complete atrioventricular canal and fewer undergoing mechanical valve replacement (p<0.01). More patients in the dexmedetomidine group were administered milrinone, epinephrine, vasopressin, benzodiazepines, opiates, and adjunct pain and sedative medications (p<0.01). The dexmedetomidine group had greater time on the ventilator [7 (4.5–11) versus 6 (4–10) days (median, interquartile range) p<0.01] and similar ICU length of stay, hospital length of stay, and mortality compared with controls. Mixed-effects modelling clustered on institution did not show beneficial effect of dexmedetomidine on ventilator time, ICU stay, or hospital length of stay. Conclusions: The use of dexmedetomidine was not associated with the decreased ventilatory time. Routine use of dexmedetomidine is not warranted in this patient population.
The fiduciary duty principle has taken center-stage in the debate concerning the integration of environmental, social and corporate governance (ESG) performance. For decades, it has been widely agreed that “trustees or fiduciaries [are to manage] assets in the best interests of the individual beneficiaries or investors: the ultimate recipients or owners of the funds” (Chapter 1 of this volume). The “best interests” of the beneficiaries or investors have typically been reduced to their financial interests (Langbein and Posner 1980; Sandberg 2011). Addressing this fiduciary duty problem is seen as pivotal for future development of the socially responsible investment (SRI) market in general (e.g., Richardson 2009). As a result, an ever-increasing body of literature has focused on the analysis of the financial implications of incorporating nonfinancial interests into investment decision-making. Over the past three decades, several thousand “does it pay to be green?” or “does it pay to be responsible?” studies have been published with the aim to shed light on this relationship (for excellent – albeit slightly contradictory – overviews see, for example, Margolis and Walsh 2003; Orlitzky et al. 2003; Salzmann et al. 2005). It is generally agreed that the inconclusiveness within this body of literature is a result of the diversity of the underlying measures of financial performance, the methodologies applied, the sample sizes analyzed, the time horizons under investigation, the respective industries analyzed and, most importantly, the operationalization of the environmental or social performance of the companies under investigation (cf. Horváthová 2010; Ullman 1985).