To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Background: Based on the vulnerability model, several studies indicate that low self-esteem seems to contribute to depressive symptoms. Aims: The aim of this study was to treat depressive symptoms in a cognitive behavioural group therapy, focusing on the enhancement of self-esteem, and to explore co-variation in depressive symptoms and the level of self-esteem. Method: The Multidimensional Self-esteem Scale (MSWS) and the Beck Depression Inventory (BDI) were administered to 147 psychiatric in-patients with current depressive symptoms due to an affective disorder (major depression, bipolar I, dysthymia). Self-esteem was measured pre-treatment (t0) and post-treatment (t4, after 5 weeks of eight group sessions); the BDI was applied weekly. A linear mixed growth analysis was conducted to estimate the change in depressive symptoms including interactions with self-esteem. Results: Within the 5 weeks of group therapy, depressive symptoms showed a linear decline, which was stronger for patients with higher gains in self-esteem between t0 and t4. Self-esteem at t0 was unrelated to the change in depression but predicted self-esteem at t4. Conclusions: Treating depressive symptoms in a cognitive behavioural group therapy in a naturalistic setting might have a positive effect on the process of recovery. Moreover, depressive symptoms and level of self-esteem seemed to co-vary.
Abstract. We continue the study of effective Hausdorff dimension as it was initiated by Lutz. Whereas he uses a generalization of martingales on the Cantor space to introduce this notion we give a characterization in terms of effective s-dimensional Hausdorff measures, similar to the effectivization of Lebesgue measure by Martin-Löf. It turns out that effective Hausdorff dimension allows to classify sequences according to their ‘degree’ of algorithmic randomness, i.e., their algorithmic density of information. Earlier the works of Staiger and Ryabko showed a deep connection between Kolmogorov complexity and Hausdorff dimension. We further develop this relationship and use it to give effective versions of some important properties of (classical) Hausdorff dimension. Finally, we determine the effective dimension of some objects arising in the context of computability theory, such as degrees and spans.
§1. Introduction. Generally speaking, the concepts of Hausdorff measure and dimension are a generalization of Lebesgue measure theory. In the early 20th century, Hausdorff  used Caratheodory's construction of measures to define a whole family of outer measures. For examining a set of a peculiar topological or geometrical nature Lebesgue measure often is too coarse to investigate the features of the set, so one may ‘pick’ a measure from this family of outer measures that is suited to study this particular set. This is one reason why Hausdorff measure and dimension became a prominent tool in fractal geometry.
Hausdorff dimension is extensively studied in the context of dynamical systems, too. On the Cantor space, the space of all infinite binary sequences, the interplay between dimension and concepts from dynamical systems such as entropy becomes really close. Results of Besicovitch  and Eggleston  early brought forth a correspondence between the Hausdorff dimension of frequency sets (i.e., sets of sequences in which every symbol occurs with a certain frequency) and the entropy of a process creating such sequences as typical outcomes. Besides, under certain conditions the Hausdorff dimension of a set in the Cantor space equals the topological entropy of this set, viewed as a shift space.
Abstract. A set A is Martin-Lof random iff the class ﹛A﹜ does not have measure 0. A set A is PA-complete if one can compute relative to A a consistent and complete extension of Peano Arithmetic. It is shown that every Martin-Lof random set either permits to solve the halting problem K or is not PA-complete. This result implies a negative answer to the question of Ambos-Spies and Kucera whether there is a Martin-Lof random set not above K which is also PA-complete.
Introduction. Gacs  and Kucera [7, 8] showed that every set can be computed relative to a Martin-Lof random set. In particular, for every set B there is a Martin-Lof random set A such that where K is the halting problem. A can even be chosen such that the reduction from B to A is a weak truth-table reduction, Merkle and Mihailovic  give a simplified proof for this fact.
A natural question is whether it is necessary to go up to the degree of in order to find the random set A. Martin-L of random sets can be found below every set which is PA-complete, so there are Martin-Lof random sets in low and in hyperimmune-free Turing degrees. A set A is called PA-complete if one can compute relative to A a complete and consistent extension of the set of first-order formulas provable in Peano Arithmetic. An easier and equivalent definition of being PA-complete is to say that given any partial-recursive and ﹛0, 1﹜-valued function, one can compute relative to A a total extension Ψ of. One can of course choose Ψ such that also Ψ is ﹛0, 1﹜-valued.
Extending all possible ﹛0, 1﹜-valued partial-recursive functions is as difficult as to compute a ﹛0, 1﹜-valued DNR function. A diagonally nonrecursive (DNR) function f satisfies whenever is defined.
We present first results of a new heterodyne spectrometer dedicated to high-resolution spectroscopy of molecules of astrophysical importance. The spectrometer, based on a room-temperature heterodyne receiver, is sensitive to frequencies between 75 and 110 GHz with an instantaneous bandwidth of currently 2.5 GHz in a single sideband. The system performance, in particular the sensitivity and stability, is evaluated. Proof of concept of this spectrometer is demonstrated by recording the emission spectrum of methyl cyanide, CH3CN. Compared to state-of-the-art radio telescope receivers the instrument is less sensitive by about one order of magnitude. Nevertheless, the capability for absolute intensity measurements can be exploited in various experiments, in particular for the interpretation of the ever richer spectra in the ALMA era. The ease of operation at room-temperature allows for long time integration, the fast response time for integration in chirped pulse instruments or for recording time dependent signals. Future prospects as well as limitations of the receiver for the spectroscopy of complex organic molecules (COMs) are discussed.
Using the UVES echelle spectrograph at the ESO VLT we obtained high-resolution (R=40 000) spectra of the QSO 0103-260 in the FORS Deep Field (FDF). In addition to numerous Ly forest lines we identified 16 metal absorption systems with redshifts between 0.97 < z < 3.36. A comparison of the observed redshift distributions of the metal line systems and of the spectroscopically observed galaxies in the FDF shows that the distribution of metal absorption clouds and of the galaxies along the line of sight to the QSO are well correlated and obviously trace the cosmic structure in the direction of the FDF.
Bipolar disorder is a highly heritable polygenic disorder. Recent
enrichment analyses suggest that there may be true risk variants for
bipolar disorder in the expression quantitative trait loci (eQTL) in the
We sought to assess the impact of eQTL variants on bipolar disorder risk
by combining data from both bipolar disorder genome-wide association
studies (GWAS) and brain eQTL.
To detect single nucleotide polymorphisms (SNPs) that influence
expression levels of genes associated with bipolar disorder, we jointly
analysed data from a bipolar disorder GWAS (7481 cases and 9250 controls)
and a genome-wide brain (cortical) eQTL (193 healthy controls) using a
Bayesian statistical method, with independent follow-up replications. The
identified risk SNP was then further tested for association with
hippocampal volume (n = 5775) and cognitive performance
(n = 342) among healthy individuals.
Integrative analysis revealed a significant association between a brain
eQTL rs6088662 on chromosome 20q11.22 and bipolar disorder (log Bayes
factor = 5.48; bipolar disorder P =
5.85×10–5). Follow-up studies across multiple independent
samples confirmed the association of the risk SNP (rs6088662) with gene
expression and bipolar disorder susceptibility (P =
3.54×10–8). Further exploratory analysis revealed that
rs6088662 is also associated with hippocampal volume and cognitive
performance in healthy individuals.
Our findings suggest that 20q11.22 is likely a risk region for bipolar
disorder; they also highlight the informative value of integrating
functional annotation of genetic variants for gene expression in
advancing our understanding of the biological basis underlying complex
disorders, such as bipolar disorder.
Because of stability constraints, most numerical schemes applied to hyperbolic systems of equations turn out to be costly when the flux term is multiplied by some very large scalar. This problem emerges with the M1 system of equations in the field of radiotherapy when considering heterogeneous media with very disparate densities. Additionally, the flux term of the M1 system is non-linear, and in order for the model to be well-posed the numerical solution needs to fulfill conditions called realizability. In this paper, we propose a numerical method that overcomes the stability constraint and preserves the realizability property. For this purpose, we relax the M1 system to obtain a linear flux term. Then we extend the stencil of the difference quotient to obtain stability. The scheme is applied to a radiotherapy dose calculation example.
Rapid changes in agricultural systems call for profound changes in agricultural research and extension practices. The Diagnosis, Design, Assessment, Training and Extension (DATE) approach was developed and applied to co-design Conservation Agriculture-based cropping systems in contrasted situations. DATE is a multi-scale, multi-stakeholder participatory approach that integrates scientific and local knowledge. It emerged in response to questions raised by and issues encountered in the design of innovative systems. A key feature of this approach is the high input of innovative systems which are often although not exclusively based on conservation agricultural practices. Prototyping of innovative cropping systems (ICSs) largely relies on a conceptual model of soil–plant–macrofauna–microorganism system functioning. By comparing the implementation of the DATE approach and conservation agriculture-based cropping systems in Madagascar, Lao PDR, and Cambodia, we show that: (i) the DATE approach is flexible enough to be adapted to local conditions; (ii) market conditions need to be taken into account in designing agricultural development scenarios; and (iii) the learning process during the transition to conservation agriculture requires time. The DATE approach not only enables the co-design of ICSs with farmers, but also incorporates training and extension dimensions. It feeds back practitioners’ questions to researchers, and provides a renewed and extended source of innovation to farmers.
In this paper we present a study of the switching kinetics of SrTiO3 based resistive switching memory devices. A pulse scheme is used to cycle the cells between the high resistive state (HRS) and the low resistive state (LRS) thereby monitoring the transient currents for a precise analysis of the SET and RESET transitions. By variation of the width and amplitude of the applied pulses the switching kinetics are studied between 10-8 and 104 s. Taking the pre-switching currents into account, a power dependency of the SET is found that emphasizes the importance of local Joule heating for the nonlinearity of the switching kinetics.
The present study is dealing with the basic physics for a novel way to generate a free-formed ceramic body, not like common layer by layer, but directly by Selective Volume Sintering (SVS) in a compact block of ceramic powder. To penetrate with laser light into the volume of a ceramic powder compact it is necessary to investigate the light scattering properties of ceramic powders. Compared with polymers and metals, ceramic materials are unique as they offer a wide optical window of transparency. The optical window typically ranges from below 0.3 up to 5 µm wave length. In the present study thin layers of quartz glass (SiO2) particles have been prepared. As a function of layer thickness and the particle size, transmission and reflection spectra in a wave length range between 0.5 and 2.5 µm have been recorded. Depending on the respective particle size and by choosing a proper relation between particle size and wave length of the incident laser radiation, it is found that light can penetrate a powder compact up to a depth of a few millimeters. With an adjustment of the light absorption properties of the compact the initiation of sintering in the volume of the compact is possible.
The Stern Review received widespread attention for its innovative approach to the economics of climate change when it appeared in 2006, and generated controversies that have continued to this day. One key controversy concerns the magnitude of the expected impacts of climate change. Stern's estimates, based on results from the PAGE2002 model, sounded substantially greater than those produced by many other models, leading several critics to suggest that Stern had inflated his damage figures. We reached the opposite conclusion in a recent application of PAGE2002 in a study of the costs to the US economy of inaction on climate change. This chapter describes our revisions to the PAGE estimates, and explains our conclusion that the model runs used in the Stern Review may well underestimate US and global damages. Stern's estimates from PAGE2002 implied that mean business-as-usual damages in 2100 would represent just 0.4 percent of GDP for the United States and 2.2 percent of GDP for the world. Our revisions and reinterpretation of the PAGE model imply that climate damages in 2100 could reach 2.6 percent of GDP for the United States and 10.8 percent for the world.
The Stern Review received widespread attention for its innovative approach to the economics of climate change when it appeared in 2006. It represented a break with conventional analyses in several respects, generating debates about climate economics that have continued to this day. One of the foundations of the Stern analysis was the use of the PAGE2002 model (Alberth and Hope 2007; Hope 2006a; Wahba and Hope 2006) to estimate the damages that would be expected under business-as-usual conditions (i.e., in the absence of effective new climate policies). Based on PAGE, Stern estimated that the present welfare cost of climate damages through 2200 could amount to 5 percent of world output under a relatively narrow definition of damages, up to as much as 20 percent under the broadest definition. These estimates were substantially greater than those produced by many other models, leading several critics to suggest that Stern had inflated his damage figures (Byatt et al. 2006; Lomborg 2006; Mendelsohn 2006; Nordhaus 2007c; Tol and Yohe 2006).
In contrast with the notion of complexity, a set A is called anti-complex if the Kolmogorov complexity of the initial segments of A chosen by a recursive function is always bounded by the identity function. We show that, as for complexity, the natural arena for examining anti-complexity is the weak-truth table degrees. In this context, we show the equivalence of anti-complexity and other lowness notions such as r.e. traceability or being weak truth-table reducible to a Schnorr trivial set. A set A is anti-complex if and only if it is reducible to another set B with tiny use, whereby we mean that the use function for reducing A to B can be made to grow arbitrarily slowly, as gauged by unbounded nondecreasing recursive functions. This notion of reducibility is then studied in its own right, and we also investigate its range and the range of its uniform counterpart.