Showing papers by "University of Bath published in 2012"

Academic Engagement and Commercialisation: A Review of the Literature on University-Industry Relations

Abstract: A considerable body of work highlights the relevance of collaborative research, contract research, consulting and informal relationships for university-industry knowledge transfer. We present a systematic review of research on academic scientists’ involvement in these activities to which we refer as ‘academic engagement’. Apart from extracting findings that are generalisable across studies, we ask how academic engagement differs from commercialization, defined as intellectual property creation and academic entrepreneurship. We identify the individual, organizational and institutional antecedents and consequences of academic engagement, and then compare these findings with the antecedents and consequences of commercialization. Apart from being more widely practiced, academic engagement is distinct from commercialization in that it is closely aligned with traditional academic research activities, and pursued by academics to access resources supporting their research agendas. We conclude by identifying future research needs, opportunities for methodological improvement and policy interventions. (Published version available via open access)

Psychological therapies for the management of chronic pain (excluding headache) in adults

Abstract: Background Psychological treatments are designed to treat pain, distress and disability, and are in common practice. This review updates and extends the 2009 version of this systematic review. Objectives To evaluate the effectiveness of psychological therapies for chronic pain (excluding headache) in adults, compared with treatment as usual, waiting list control, or placebo control, for pain, disability, mood and catastrophic thinking. Search methods We identified randomised controlled trials (RCTs) of psychological therapy by searching CENTRAL, MEDLINE, EMBASE and Psychlit from the beginning of each abstracting service until September 2011. We identified additional studies from the reference lists of retrieved papers and from discussion with investigators. Selection criteria Full publications of RCTs of psychological treatments compared with an active treatment, waiting list or treatment as usual. We excluded studies if the pain was primarily headache, or was associated with a malignant disease. We also excluded studies if the number of patients in any treatment arm was less than 20. Data collection and analysis Forty-two studies met our criteria and 35 (4788 participants) provided data. Two authors rated all studies. We coded risk of bias as well as both the quality of the treatments and the methods using a scale designed for the purpose. We compared two main classes of treatment (cognitive behavioural therapy(CBT) and behaviour therapy) with two control conditions (treatment as usual; active control) at two assessment points (immediately following treatment and six months or more following treatment), giving eight comparisons. For each comparison, we assessed treatment effectiveness on four outcomes: pain, disability, mood and catastrophic thinking, giving a total of 32 possible analyses, of which there were data for 25. Main results Overall there is an absence of evidence for behaviour therapy, except a small improvement in mood immediately following treatment when compared with an active control. CBT has small positive effects on disability and catastrophising, but not on pain or mood, when compared with active controls. CBT has small to moderate effects on pain, disability, mood and catastrophising immediately post-treatment when compared with treatment as usual/waiting list, but all except a small effect on mood had disappeared at follow-up. At present there are insufficient data on the quality or content of treatment to investigate their influence on outcome. The quality of the trial design has improved over time but the quality of treatments has not. Authors' conclusions Benefits of CBT emerged almost entirely from comparisons with treatment as usual/waiting list, not with active controls. CBT but not behaviour therapy has weak effects in improving pain, but only immediately post-treatment and when compared with treatment as usual/waiting list. CBT but not behaviour therapy has small effects on disability associated with chronic pain, with some maintenance at six months. CBT is effective in altering mood and catastrophising outcomes, when compared with treatment as usual/waiting list, with some evidence that this is maintained at six months. Behaviour therapy has no effects on mood, but showed an effect on catastrophising immediately post-treatment. CBT is a useful approach to the management of chronic pain. There is no need for more general RCTs reporting group means: rather, different types of studies and analyses are needed to identify which components of CBT work for which type of patient on which outcome/s, and to try to understand why.

Socioeconomic status and smoking: a review

Abstract: Smoking prevalence is higher among disadvantaged groups, and disadvantaged smokers may face higher exposure to tobacco's harms. Uptake may also be higher among those with low socioeconomic status (SES), and quit attempts are less likely to be successful. Studies have suggested that this may be the result of reduced social support for quitting, low motivation to quit, stronger addiction to tobacco, increased likelihood of not completing courses of pharmacotherapy or behavioral support sessions, psychological differences such as lack of self-efficacy, and tobacco industry marketing. Evidence of interventions that work among lower socioeconomic groups is sparse. Raising the price of tobacco products appears to be the tobacco control intervention with the most potential to reduce health inequalities from tobacco. Targeted cessation programs and mass media interventions can also contribute to reducing inequalities. To tackle the high prevalence of smoking among disadvantaged groups, a combination of tobacco control measures is required, and these should be delivered in conjunction with wider attempts to address inequalities in health.

Fear-avoidance model of chronic pain: the next generation.

Abstract: Objective: The fear-avoidance (FA) model of chronic pain describes how individuals experiencing acute pain may become trapped into a vicious circle of chronic disability and suffering. We propose to extend the FA model by adopting a motivational perspective on chronic pain and disability. Methods: A narrative review. Results: There is ample evidence to support the validity of the FA model as originally formulated. There are, however, some key challenges that call for a next generation of the FA model. First, the FA model has its roots in psychopathology, and investigators will have to find a way to account for findings that do not easily fit within such framework. Second, the FA model needs to address the dynamics and complexities of disability and functional recovery. Third, the FA model should incorporate the idea that pain-related fear and avoidance occurs in a context of multiple and often competing personal goals. Discussion: To address these 3 key challenges, we argue that the next generation of the FA model needs to more explicitly adopt a motivational perspective, one that is built around the organizing powers of goals and self-regulatory processes. Using this framework, the FA model is recast as capturing the persistent but futile attempts to solve pain-related problems to protect and restore life goals.

Corporate Social Responsibility and Institutional Theory: New Perspectives on Private Governance

Abstract: Corporate Social Responsibility (CSR) has become a pervasive topic in the business literature, but has largely neglected the role of institutions. This introductory article to the Special Issue of Socio-Economic Review examines the potential contributions of institutional theory to understanding CSR as a mode of governance. This perspective suggests going beyond grounding CSR in the voluntary behaviour of companies, and understanding the larger historical and political determinants of whether and in what forms corporations take on social responsibilities. Historically, the prevailing notion of CSR emerged through the defeat of more institutionalized forms of social solidarity in liberal market economies. Meanwhile, CSR is more tightly linked to formal institutions of stakeholder participation or state intervention in other advanced economies. The tensions between business-driven and multi-stakeholder forms of CSR extend to the transnational level, where the form and meaning of CSR remain highly contested. CSR research and practice thus rest on a basic paradox between a liberal notion of voluntary engagement and a contrary implication of socially binding responsibilities. Institutional theory seems to be a promising avenue to explore how the boundaries between business and society are constructed in different ways, and improve our understanding of the effectiveness of CSR within the wider institutional field of economic governance.

Environmentally conscious machining of difficult-to-machine materials with regard to cutting fluids

Abstract: Machining difficult-to-machine materials such as alloys used in aerospace, nuclear and medical industries are usually accompanied with low productivity, poor surface quality and short tool life. Despite the broad use of the term difficult-to-machine or hard-to-cut materials, the area of these types of materials and their properties are not clear yet. On the other hand, using cutting fluids is a common technique for improving machinability and has been acknowledged since early 20th. However, the environmental and health hazards associated with the use of conventional cutting fluids together with developing governmental regulations have resulted in increasing machining costs. The aim of this paper is to review and identify the materials known as difficult-to-machine and their properties. In addition, different cutting fluids are reviewed and major health and environmental concerns about their usage in material cutting industries are defined. Finally, advances in reducing and/or eliminating the use of conventional cutting fluids are reviewed and discussed.

Kesterite Thin‐Film Solar Cells: Advances in Materials Modelling of Cu2ZnSnS4

Abstract: Quaternary semiconducting materials based on the kesterite (A2BCX4) mineral structure are the most promising candidates to overtake the current generation of light-absorbing materials for thin-film solar cells. Cu2ZnSnS4 (CZTS), Cu2ZnSnSe4 (CZTSe) and their alloy Cu2ZnSn(Se,S)4 consist of abundant, low-cost and non-toxic elements, unlike current CdTe and Cu(In,Ga)Se2 based technologies. Zinc-blende related structures are formed by quaternary compounds, but the complexity associated with the multi-component system introduces difficulties in material growth, characterization, and application. First-principles electronic structure simulations, performed over the past five years, that address the structural, electronic, and defect properties of this family of compounds are reviewed. Initial predictions of the bandgaps and crystal structures have recently been verified experimentally. The calculations highlight the role of atomic disorder on the cation sub-lattice, as well as phase separation of Cu2ZnSnS4 into ZnS and CuSnS3, on the material performance for light-to-electricity conversion in photovoltaic devices. Finally, the current grand challenges for materials modeling of thin-film solar cells are highlighted.

Systematic Review and Evidence Synthesis as a Practice and Scholarship Tool

Abstract: Reviews of existing research evidence have the potential to inform both practice and scholarship. This opportunity is currently not being fully realized in management and organization studies due to the limitations of traditional methods of review, which fail to identify clearly what is known and not known about a given topic. For practitioners, systematic review can help address managerial problems by producing a reliable knowledge base through accumulating findings from a range of studies. For scholars, systematic review can enhance methodological rigour as well as highlight opportunities for further research. Systematic reviews are guided by a set of principles rather than a specific, inflexible and restricted protocol. By revealing these principles, outlining a systematic review methodology and offering examples we hope that this chapter helps both practitioners and scholars to use systematic review to inform their practice.

Amidines, isothioureas, and guanidines as nucleophilic catalysts.

Abstract: Over the last ten years there has been a huge increase in development and applications of organocatalysis in which the catalyst acts as a nucleophile. Amidines and guanidines are often only thought of as strong organic bases however, a number of small molecules containing basic functional groups have been shown to act as efficient nucleophilic catalysts. This tutorial review highlights the use of amidine, guanidine, and related isothiourea catalysts in organic synthesis, as well as the evidence for the nucleophilic nature of these catalysts. The most common application of these catalysts to date has been in acyl transfer reactions, although the application of these catalysts towards other reactions is an increasing area of interest. In this respect, amidine and guanidine derived catalysts have been shown to be effective in catalysing aldol reactions, Morita–Baylis–Hillman reactions, conjugate additions, carbonylations, methylations, silylations, and brominations.

Low loss silica hollow core fibers for 3–4 μm spectral region

Abstract: We describe a silica hollow-core fiber for mid-infrared transmission with a minimum attenuation of 34 dB/km at 3050 nm wavelength. The design is based on the use of a negative curvature core wall. Similar fiber designed for longer wavelengths has a transmission band extending beyond 4 µm.

Integrating Emotions into the Analysis of Institutional Work

Abstract: We argue for the importance of including analyses of emotional and unconscious processes in the study of institutional work. We develop a framework that integrates emotions and their connection to domination, and we offer a typology of interactions between the emotional and cognitive antecedents of institutional maintenance, disruption, and creation. We conclude by discussing the implications of paying closer attention to emotions for future institutional research, including questions regarding reproduction versus change, intentionality, and rationality.

An Institution of Corporate Social Responsibility (CSR) in Multi-National Corporations (MNCs): Form and Implications

Abstract: This article investigates corporate social responsibility (CSR) as an institution within UK multi-national corporations (MNCs). In the context of the literature on the institutionalization of CSR and on critical CSR, it presents two main findings. First, it contributes to the CSR mainstream literature by confirming that CSR has not only become institutionalized in society but that a form of this institution is also present within MNCs. Secondly, it contributes to the critical CSR literature by suggesting that unlike broader notions of CSR shared between multiple stakeholders, MNCs practise a form of CSR that undermines the broader stakeholder concept. By increasingly focusing on strategic forms of CSR activity, MNCs are moving away from a societal understanding of CSR that focuses on redressing the impacts of their operations through stakeholder concerns, back to any activity that supports traditional business imperatives. The implications of this shift are considered using institutional theory to evaluate macro-institutional pressures for CSR activity and the agency of powerful incumbents in the contested field of CSR.

Environmental Management in SMEs in the UK: Practices, Pressures and Perceived Benefits

Abstract: Environmental management represents a significant challenge for small businesses, and prior research has shown that they are typically less engaged with environmental issues than their larger counterparts. At the same time, prior research has seldom explored engagement among small and medium-sized companies (SMEs) with the wide variety of practices that are encompassed by environmental management, nor has it sought to explore heterogeneity among SMEs. In this study, we analyse the extent of SME involvement in a wide range of environmental management practices and the differences between small and medium-sized businesses. We also explore SME perceptions of pressures for, and benefits of, engagement with environmental issues. Our findings show that most small businesses are engaged in some environmental initiatives but that there is significant heterogeneity in the engagement of small and medium-sized businesses. Consistent with this, we show that the smallest companies perceive significantly fewer benefits of engagement with environmental issues. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.

A Brief Index of Affective Job Satisfaction

Abstract: This article responds to criticisms that affective job satisfaction research suffers serious measurement problems: Noncomparable measures; studies conceptualizing job satisfaction affectively but measuring it cognitively; and ad hoc measures lacking systematic development and validation, especially across populations by nationality, job level, and job type. We address these problems through a series of qualitative (total N = 28) and quantitative (total N = 901) studies to systematically develop and validate a short affective job satisfaction measure ultimately deriving from Brayfield and Rothe’s (1951) job satisfaction index. Unlike any previous job satisfaction measure, the resulting four-item Brief Index of Affective Job Satisfaction is overtly affective, minimally cognitive, and optimally brief. The new measure also differs from any previous job satisfaction measure in being comprehensively validated not just for internal consistency reliability, temporal stability, convergent and criterion-related validities, but also for cross-population invariance by nationality, job level, and job type.

‘Too interconnected to fail’ financial network of US CDS market: Topological fragility and systemic risk

Abstract: A small segment of credit default swaps (CDS) on residential mortgage backed securities (RMBS) stand implicated in the 2007 financial crisis. The dominance of a few big players in the chains of insurance and reinsurance for CDS credit risk mitigation for banks’ assets has led to the idea of too interconnected to fail (TITF) resulting, as in the case of AIG, of a tax payer bailout. We provide an empirical reconstruction of the US CDS network based on the FDIC Call Reports for off balance sheet bank data for the 4th quarter in 2007 and 2008. The propagation of financial contagion in networks with dense clustering which reflects high concentration or localization of exposures between few participants will be identified as one that is TITF. Those that dominate in terms of network centrality and connectivity are called ‘super-spreaders’. Management of systemic risk from bank failure in uncorrelated random networks is different to those with clustering. As systemic risk of highly connected financial firms in the CDS (or any other) financial markets is not priced into their holding of capital and collateral, we design a super-spreader tax based on eigenvector centrality of the banks which can mitigate potential socialized losses.

The Theory of Scale Functions for Spectrally Negative Lévy Processes

Abstract: The purpose of this review article is to give an up to date account of the theory and applications of scale functions for spectrally negative Levy processes. Our review also includes the first extensive overview of how to work numerically with scale functions. Aside from being well acquainted with the general theory of probability, the reader is assumed to have some elementary knowledge of Levy processes, in particular a reasonable understanding of the Levy–Khintchine formula and its relationship to the Levy–Ito decomposition. We shall also touch on more general topics such as excursion theory and semi-martingale calculus. However, wherever possible, we shall try to focus on key ideas taking a selective stance on the technical details. For the reader who is less familiar with some of the mathematical theories and techniques which are used at various points in this review, we note that all the necessary technical background can be found in the following texts on Levy processes; (Bertoin, Levy Processes (1996); Sato, Levy Processes and Infinitely Divisible Distributions (1999); Kyprianou, Introductory Lectures on Fluctuations of Levy Processes and Their Applications (2006); Doney, Fluctuation Theory for Levy Processes (2007)), Applebaum Levy Processes and Stochastic Calculus (2009).

Predicting students' physical activity and health-related well-being: A prospective cross-domain investigation of motivation across school physical education and exercise settings

Abstract: A three-wave prospective design was used to assess a model of motivation guided by self-determination theory (Ryan & Deci, 2008) spanning the contexts of school physical education (PE) and exercise. The outcome variables examined were health-related quality of life (HRQoL), physical self-concept (PSC), and 4 days of objectively assessed estimates of activity. Secondary school students (n = 494) completed questionnaires at three separate time points and were familiarized with how to use a sealed pedometer. Results of structural equation modeling supported a model in which perceptions of autonomy support from a PE teacher positively predicted PE-related need satisfaction (autonomy, competence, and relatedness). Competence predicted PSC, whereas relatedness predicted HRQoL. Autonomy and competence positively predicted autonomous motivation toward PE, which in turn positively predicted autonomous motivation toward exercise (i.e., 4-day pedometer step count). Autonomous motivation toward exercise positively predicted step count, HRQoL, and PSC. Results of multisample structural equation modeling supported gender invariance. Suggestions for future work are discussed.

Do Consumers Care About Ethical-Luxury?

Abstract: This article explores the extent to which consumers consider ethics in luxury goods consumption. In particular, it explores whether there is a significant difference between consumers’ propensity to consider ethics in luxury versus commodity purchase and whether consumers are ready to purchase ethical-luxury. Prior research in ethical consumption focuses on low value, commoditized product categories such as food, cosmetics and high street apparel. It is debatable if consumers follow similar ethical consumption patterns in luxury purchases. Findings indicate that consumers’ propensity to consider ethics is significantly lower in luxury purchases when compared to commoditized purchases and explores some of the potential reasons for this reduced propensity to identify or act upon ethical issues in luxury consumption.

Does the internet change how we die and mourn? Overview and analysis

Abstract: The article outlines the issues that the internet presents to death studies. Part 1 describes a range of online practices that may affect dying, the funeral, grief and memorialization, inheritance and archaeology; it also summarizes the kinds of research that have been done in these fields. Part 2 argues that these new online practices have implications for, and may be illuminated by, key concepts in death studies: the sequestration (or separation from everyday life) of death and dying, disenfranchisement of grief, private grief, social death, illness and grief narratives, continuing bonds with the dead, and the presence of the dead in society. In particular, social network sites can bring dying and grieving out of both the private and public realms and into the everyday life of social networks beyond the immediate family, and provide an audience for once private communications with the dead.

Structure of Cellulose Microfibrils in Primary Cell Walls from Collenchyma

Abstract: In the primary walls of growing plant cells, the glucose polymer cellulose is assembled into long microfibrils a few nanometers in diameter. The rigidity and orientation of these microfibrils control cell expansion; therefore, cellulose synthesis is a key factor in the growth and morphogenesis of plants. Celery (Apium graveolens) collenchyma is a useful model system for the study of primary wall microfibril structure because its microfibrils are oriented with unusual uniformity, facilitating spectroscopic and diffraction experiments. Using a combination of x-ray and neutron scattering methods with vibrational and nuclear magnetic resonance spectroscopy, we show that celery collenchyma microfibrils were 2.9 to 3.0 nm in mean diameter, with a most probable structure containing 24 chains in cross section, arranged in eight hydrogen-bonded sheets of three chains, with extensive disorder in lateral packing, conformation, and hydrogen bonding. A similar 18-chain structure, and 24-chain structures of different shape, fitted the data less well. Conformational disorder was largely restricted to the surface chains, but disorder in chain packing was not. That is, in position and orientation, the surface chains conformed to the disordered lattice constituting the core of each microfibril. There was evidence that adjacent microfibrils were noncovalently aggregated together over part of their length, suggesting that the need to disrupt these aggregates might be a constraining factor in growth and in the hydrolysis of cellulose for biofuel production.

Fetal Testosterone Influences Sexually Dimorphic Gray Matter in the Human Brain

Abstract: In nonhuman species, testosterone is known to have permanent organizing effects early in life that predict later expression of sex differences in brain and behavior. However, in humans, it is still unknown whether such mechanisms have organizing effects on neural sexual dimorphism. In human males, we show that variation in fetal testosterone (FT) predicts later local gray matter volume of specific brain regions in a direction that is congruent with sexual dimorphism observed in a large independent sample of age-matched males and females from the NIH Pediatric MRI Data Repository. Right temporoparietal junction/posterior superior temporal sulcus (RTPJ/pSTS), planum temporale/parietal operculum (PT/PO), and posterior lateral orbitofrontal cortex (plOFC) had local gray matter volume that was both sexually dimorphic and predicted in a congruent direction by FT. That is, gray matter volume in RTPJ/pSTS was greater for males compared to females and was positively predicted by FT. Conversely, gray matter volume in PT/PO and plOFC was greater in females compared to males and was negatively predicted by FT. Subregions of both amygdala and hypothalamus were also sexually dimorphic in the direction of Male > Female, but were not predicted by FT. However, FT positively predicted gray matter volume of a non-sexually dimorphic subregion of the amygdala. These results bridge a long-standing gap between human and nonhuman species by showing that FT acts as an organizing mechanism for the development of regional sexual dimorphism in the human brain.

Energy efficient process planning for CNC machining

Abstract: Machining is one of the major activities in manufacturing industries and is responsible for a significant portion of the total consumed energy in this sector. Performing machining processes with better energy efficiency will, therefore, significantly reduce the total industrial consumption of energy. In this paper, a framework is presented to validate the introduction of energy consumption in the objectives of process planning for CNC machining. The state of the art in process planning and energy consumption in manufacturing research is utilised as a basis for the framework. A mathematical representation of the logic used is presented followed by two sets of experiments on energy consumption in machining to validate the logic. It is shown that energy consumption can be added to multi-criteria process planning systems as a valid objective and the discussion on using resource models for energy consumption estimation concludes the paper. These experiments represent a part test procedure machining proposal for the new environmental machine standard ISO 14955 Part 3.

Kinetics of light-driven oxygen evolution at alpha-Fe2O3 electrodes.

Abstract: The kinetics of light-driven oxygen evolution at polycrystalline alpha-Fe2O3 layers prepared by aerosol-assisted chemical vapour deposition has been studied using intensity modulated photocurrent spectroscopy (IMPS). Analysis of the frequency-dependent IMPS response gives information about the competition between the 4-electron oxidation of water by photogenerated holes and losses due to electron-hole recombination via surface states. The very slow kinetics of oxygen evolution indicates the presence of a kinetic bottleneck in the overall process. Surface treatment of the alpha-Fe2O3 with dilute cobalt nitrate solution leads to a remarkable improvement in the photocurrent response, but contrary to expectation, the results of this study show that this is not due to catalysis of hole transfer but is instead the consequence of almost complete suppression of surface recombination.

Methicillin Resistance Alters the Biofilm Phenotype and Attenuates Virulence in Staphylococcus aureus Device-Associated Infections

Abstract: Clinical isolates of Staphylococcus aureus can express biofilm phenotypes promoted by the major cell wall autolysin and the fibronectin-binding proteins or the icaADBC-encoded polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG). Biofilm production in methicillin-susceptible S. aureus (MSSA) strains is typically dependent on PIA/PNAG whereas methicillin-resistant isolates express an Atl/FnBP-mediated biofilm phenotype suggesting a relationship between susceptibility to β-lactam antibiotics and biofilm. By introducing the methicillin resistance gene mecA into the PNAG-producing laboratory strain 8325-4 we generated a heterogeneously resistant (HeR) strain, from which a homogeneous, high-level resistant (HoR) derivative was isolated following exposure to oxacillin. The HoR phenotype was associated with a R602H substitution in the DHHA1 domain of GdpP, a recently identified c-di-AMP phosphodiesterase with roles in resistance/tolerance to β-lactam antibiotics and cell envelope stress. Transcription of icaADBC and PNAG production were impaired in the 8325-4 HoR derivative, which instead produced a proteinaceous biofilm that was significantly inhibited by antibodies against the mecA-encoded penicillin binding protein 2a (PBP2a). Conversely excision of the SCCmec element in the MRSA strain BH1CC resulted in oxacillin susceptibility and reduced biofilm production, both of which were complemented by mecA alone. Transcriptional activity of the accessory gene regulator locus was also repressed in the 8325-4 HoR strain, which in turn was accompanied by reduced protease production and significantly reduced virulence in a mouse model of device infection. Thus, homogeneous methicillin resistance has the potential to affect agr- and icaADBC-mediated phenotypes, including altered biofilm expression and virulence, which together are consistent with the adaptation of healthcare-associated MRSA strains to the antibiotic-rich hospital environment in which they are frequently responsible for device-related infections in immuno-compromised patients.

Coverage Properties of Confidence Intervals for Generalized Additive Model Components

Abstract: We study the coverage properties of Bayesian confidence intervals for the smooth component functions of generalized additive models (GAMs) represented using any penalized regression spline approach. The intervals are the usual generalization of the intervals first proposed by Wahba and Silverman in 1983 and 1985, respectively, to the GAM component context. We present simulation evidence showing these intervals have close to nominal ‘across-the-function’ frequentist coverage probabilities, except when the truth is close to a straight line/plane function. We extend the argument introduced by Nychka in 1988 for univariate smoothing splines to explain these results. The theoretical argument suggests that close to nominal coverage probabilities can be achieved, provided that heavy oversmoothing is avoided, so that the bias is not too large a proportion of the sampling variability. Otherwise, because the Bayesian intervals account for bias and variance, the coverage probabilities are surprisingly insensitive to the exact choice of smoothing parameter. The theoretical results allow us to derive alternative intervals from a purely frequentist point of view, and to explain the impact that the neglect of smoothing parameter variability has on confidence interval performance. They also suggest switching the target of inference for component-wise intervals away from smooth components in the space of the GAM identifiability constraints. Instead intervals should be produced for each function as if only the other model terms were subject to identifiability constraints. If this is done then coverage probabilities are improved.

Discovery of an Organic Trefoil Knot

Abstract: Molecular knots remain difficult to produce using the current synthetic methods of chemistry because of their topological complexity. We report here the near-quantitative self-assembly of a trefoil knot from a naphthalenediimide-based aqueous disulfide dynamic combinatorial library. The formation of the knot appears to be driven by the hydrophobic effect and leads to a structure in which the aromatic components are buried while the hydrophilic carboxylate groups remain exposed to the solvent. Moreover, the building block chirality constrains the topological conformation of the knot and results in its stereoselective synthesis. This work demonstrates that the hydrophobic effect provides a powerful strategy to direct the synthesis of entwined architectures.