810 research outputs found
General cost analysis for scholarly communication in Germany : results of the "Houghton Report" for Germany
Management Summary: Conducted within the project âEconomic Implications of New Models for Information Supply for Science and Research in Germanyâ, the Houghton Report for Germany provides a general cost and benefit analysis for scientific communication in Germany comparing different scenarios according to their specific costs and explicitly including the German National License Program (NLP).
Basing on the scholarly lifecycle process model outlined by Björk (2007), the study compared the following scenarios according to their accounted costs:
- Traditional subscription publishing,
- Open access publishing (Gold Open Access; refers primarily to journal publishing where access is free of charge to readers, while the authors or funding organisations pay for publication)
- Open Access self-archiving (authors deposit their work in online open access institutional or subject-based repositories, making it freely available to anyone with Internet access; further divided into (i) CGreen Open Accessâ self-archiving operating in parallel with subscription publishing; and (ii) the âoverlay servicesâ model in which self-archiving provides the foundation for overlay services (e.g. peer review, branding and quality control services))
- the NLP.
Within all scenarios, five core activity elements (Fund research and research communication; perform research and communicate the results; publish scientific and scholarly works; facilitate dissemination, retrieval and preservation; study publications and apply the knowledge) were modeled and priced with all their including activities.
Modelling the impacts of an increase in accessibility and efficiency resulting from more open access on returns to R&D over a 20 year period and then comparing costs and benefits, we find that the benefits of open access publishing models are likely to substantially outweigh the costs and, while smaller, the benefits of the German NLP also exceed the costs.
This analysis of the potential benefits of more open access to research findings suggests that different publishing models can make a material difference to the benefits realised, as well as the costs faced. It seems likely that more Open Access would have substantial net benefits in the longer term and, while net benefits may be lower during a transitional period, they are likely to be positive for both âauthor-paysâ Open Access publishing and the âover-lay journalsâ alternatives (âGold Open Accessâ), and for parallel subscription publishing and self-archiving (âGreen Open Accessâ). The NLP returns substantial benefits and savings at a modest cost, returning one of the highest benefit/cost ratios available from unilateral national policies during a transitional period (second to that of âGreen Open Accessâ self-archiving). Whether âGreen Open Accessâ self-archiving in parallel with subscriptions is a sustainable model over the longer term is debateable, and what impact the NLP may have on the take up of Open Access alternatives is also an important consideration. So too is the potential for developments in Open Access or other scholarly publishing business models to significantly change the relative cost-benefit of the NLP over time.
The results are comparable to those of previous studies from the UK and Netherlands. Green Open Access in parallel with the traditional model yields the best benefits/cost ratio. Beside its benefits/cost ratio, the meaningfulness of the NLP is given by its enforceability. The true costs of toll access publishing (beside the buybackâ of information) is the prohibition of access to research and knowledge for society
Large deviations for many Brownian bridges with symmetrised initial-terminal condition
Consider a large system of Brownian motions in with some
non-degenerate initial measure on some fixed time interval with
symmetrised initial-terminal condition. That is, for any , the terminal
location of the -th motion is affixed to the initial point of the
-th motion, where is a uniformly distributed random
permutation of . Such systems play an important role in quantum
physics in the description of Boson systems at positive temperature .
In this paper, we describe the large-N behaviour of the empirical path
measure (the mean of the Dirac measures in the paths) and of the mean of
the normalised occupation measures of the motions in terms of large
deviations principles. The rate functions are given as variational formulas
involving certain entropies and Fenchel-Legendre transforms. Consequences are
drawn for asymptotic independence statements and laws of large numbers.
In the special case related to quantum physics, our rate function for the
occupation measures turns out to be equal to the well-known Donsker-Varadhan
rate function for the occupation measures of one motion in the limit of
diverging time. This enables us to prove a simple formula for the large-N
asymptotic of the symmetrised trace of , where
is an -particle Hamilton operator in a trap
Self-intersection local times of random walks: Exponential moments in subcritical dimensions
Fix , not necessarily integer, with . We study the -fold
self-intersection local time of a simple random walk on the lattice up
to time . This is the -norm of the vector of the walker's local times,
. We derive precise logarithmic asymptotics of the expectation of
for scales that are bounded from
above, possibly tending to zero. The speed is identified in terms of mixed
powers of and , and the precise rate is characterized in terms of
a variational formula, which is in close connection to the {\it
Gagliardo-Nirenberg inequality}. As a corollary, we obtain a large-deviation
principle for for deviation functions satisfying
t r_t\gg\E[\|\ell_t\|_p]. Informally, it turns out that the random walk
homogeneously squeezes in a -dependent box with diameter of order to produce the required amount of self-intersections. Our main tool is
an upper bound for the joint density of the local times of the walk.Comment: 15 pages. To appear in Probability Theory and Related Fields. The
final publication is available at springerlink.co
Efficacy and toxicity of bimodal radiotherapy in WHO grade 2 meningiomas following subtotal resection with carbon ion boost:Prospective phase 2 MARCIE trial
Background: Novel radiotherapeutic modalities using carbon ions provide an increased relative biological effectiveness (RBE) compared to photons, delivering a higher biological dose while reducing radiation exposure for adjacent organs. This prospective phase 2 trial investigated bimodal radiotherapy using photons with carbon-ion (C12)-boost in patients with WHO grade 2 meningiomas following subtotal resection (Simpson grade 4 or 5).Methods:A total of 33 patients were enrolled from July 2012 until July 2020. The study treatment comprised a C12-boost (18 Gy [RBE] in 6 fractions) applied to the macroscopic tumor in combination with photon radiotherapy (50 Gy in 25 fractions). The primary endpoint was the 3-year progression-free survival (PFS), and the secondary endpoints included overall survival, safety and treatment toxicities. Results:With a median follow-up of 42 months, the 3-year estimates of PFS, local PFS and overall survival were 80.3%, 86.7%, and 89.8%, respectively. Radiation-induced contrast enhancement (RICE) was encountered in 45%, particularly in patients with periventricularly located meningiomas. Patients exhibiting RICE were mostly either asymptomatic (40%) or presented immediate neurological and radiological improvement (47%) after the administration of corticosteroids or bevacizumab in case of radiation necrosis (3/33). Treatment-associated complications occurred in 1 patient with radiation necrosis who died due to postoperative complications after resection of radiation necrosis. The study was prematurely terminated after recruiting 33 of the planned 40 patients. Conclusions:Our study demonstrates a bimodal approach utilizing photons with C12-boost may achieve a superior local PFS to conventional photon RT, but must be balanced against the potential risks of toxicities.</p
Frequency and gender differences in the use of professional home care in late life: Findings from three German old-age cohorts
Aim: The aim of this study was to investigate the frequency of and the gender
differences in the use of professional home care in Germany.
Methods: We used harmonized data from three large cohort studies from
Germany (âHealthy Aging: Gender-specific trajectories into the latest lifeâ;
AgeDifferent.de Platform). Data were available for 5,393 older individuals
(75 years and older). Mean age was 80.2 years (SD: 4.1 years), 66.6%
were female. Professional homecare outcome variables were use of
outpatient nursing care, paid household assistance, and meals on wheelsâ
services. Logistic regression models were used, adjusting for important
sociodemographic variables.
Results: Altogether 5.2% of older individuals used outpatient nursing care (6.2%
women and 3.2% men; p < 0.001), 24.2% used paid household assistance
(26.1% women and 20.5% men; p < 0.001) and 4.4% used meals on wheelsâ
services (4.5% women and 4.0% men; p = 0.49). Regression analysis revealed
that women had higher odds of using paid household assistance than men
(OR = 1.48, 95% CI: [1.24â1.76]; p < 0.001), whereas they had lower odds of
using meals on wheelsâ services (OR = 0.64, 95% CI: [0.42â0.97]; p < 0.05). No statistically significant differences in using outpatient nursing care between
women and men were found (OR = 1.26, 95% CI: [0.87â1.81]; p = 0.225).
Further, the use of home care was mainly associated with health-related
variables (e.g., stroke, Parkinsonâs disease) and walking impairments.
Conclusions: Our study showed that gender differences exist in using paid
household assistance and in culinary dependency. For example, meals on
wheelsâ services are of great importance (e.g., for individuals living alone or
for individuals with low social support). Gender differences were not identified
regarding outpatient nursing care. Use of professional home care servicesmay
contribute to maintaining autonomy and independence in old age
Kondo effect in coupled quantum dots: a Non-crossing approximation study
The out-of-equilibrium transport properties of a double quantum dot system in
the Kondo regime are studied theoretically by means of a two-impurity Anderson
Hamiltonian with inter-impurity hopping. The Hamiltonian, formulated in
slave-boson language, is solved by means of a generalization of the
non-crossing approximation (NCA) to the present problem. We provide benchmark
calculations of the predictions of the NCA for the linear and nonlinear
transport properties of coupled quantum dots in the Kondo regime. We give a
series of predictions that can be observed experimentally in linear and
nonlinear transport measurements through coupled quantum dots. Importantly, it
is demonstrated that measurements of the differential conductance , for the appropriate values of voltages and inter-dot tunneling
couplings, can give a direct observation of the coherent superposition between
the many-body Kondo states of each dot. This coherence can be also detected in
the linear transport through the system: the curve linear conductance vs
temperature is non-monotonic, with a maximum at a temperature
characterizing quantum coherence between both Kondo states.Comment: 20 pages, 17 figure
Hundreds of variants clustered in genomic loci and biological pathways affect human height
Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (Pâ<â0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
Distributed Fading Memory for Stimulus Properties in the Primary Visual Cortex
The brain has a one-back memory for visual stimuli. Neural responses to an image contain as much information about the current image as it does about another image presented immediately before
Cognitive behavioural therapy versus supportive therapy for persistent positive symptoms in psychotic disorders: The POSITIVE Study, a multicenter, prospective, single-blind, randomised controlled clinical trial
Background: It has been demonstrated that cognitive behavioural therapy (CBT) has a moderate effect on symptom reduction and on general well being of patients suffering from psychosis. However, questions regarding the specific efficacy of CBT, the treatment safety, the cost-effectiveness, and the moderators and mediators of treatment effects are still a major issue. The major objective of this trial is to investigate whether CBT is specifically efficacious in reducing positive symptoms when compared with non-specific supportive therapy (ST) which does not implement CBT-techniques but provides comparable therapeutic attention. Methods: The POSITIVE study is a multicenter, prospective, single-blind, parallel group, randomised clinical trial, comparing CBT and ST with respect to the efficacy in reducing positive symptoms in psychotic disorders. CBT as well as ST consist of 20 sessions altogether, 165 participants receiving CBT and 165 participants receiving ST. Major methodological aspects of the study are systematic recruitment, explicit inclusion criteria, reliability checks of assessments with control for rater shift, analysis by intention to treat, data management using remote data entry, measures of quality assurance (e.g. on-site monitoring with source data verification, regular query process), advanced statistical analysis, manualized treatment, checks of adherence and competence of therapists. Research relating the psychotherapy process with outcome, neurobiological research addressing basic questions of delusion formation using fMRI and neuropsychological assessment and treatment research investigating adaptations of CBT for adolescents is combined in this network. Problems of transfer into routine clinical care will be identified and addressed by a project focusing on cost efficiency. Discussion: This clinical trial is part of efforts to intensify psychotherapy research in the field of psychosis in Germany, to contribute to the international discussion on psychotherapy in psychotic disorders, and to help implement psychotherapy in routine care. Furthermore, the study will allow drawing conclusions about the mediators of treatment effects of CBT of psychotic disorders. Trial Registration Current Controlled Trials ISRCTN2924287
Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment
Biodiversity is rapidly declining1, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes4 across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades
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