2,711 research outputs found
Long-term social restrictions and lack of work activities during the COVID-19 pandemic:Impact on the daily lives of people with intellectual disabilities
Purpose: Lockdowns due to the Covid-19 pandemic may have had a disproportionate impact on the daily lives of people with intellectual disabilities. Many of them had to deal with limited social contacts for an extended period. This study explores in depth how people with intellectual disabilities in the Netherlands experienced their daily lives, in particular due to lack of access to regular work activities. Materials and methods: Eight participants with intellectual disabilities were interviewed. Interpretative Phenomenological Analysis (IPA) was employed in conducting and analysing interviews. Results and conclusions: Analysis yielded three overarching themes that are conceptually linked. Participants experienced a prolonged lack of social connections that resulted in experiences of social isolation and feelings of loneliness. This led to different kinds of struggles: either internal struggles involving negative thoughts or depressive feelings, or a perceived threat to their autonomous position in society. Meanwhile participants had to sustain their sense of self-worth in the absence of work activities. The findings emphasise the importance of social opportunities through the access to work activities for people with intellectual disabilities. Interventions are suggested to help reverse the increased social inequalities and enhance rehabilitation via work activities for people with intellectual disabilities. Implications for rehabilitation: More awareness may be raised among authorities, employers and the general public about the significant value people with intellectual disabilities attribute to meaningful social connections, in particular through work activities. Also, more awareness may be raised about the potential adverse effects of the loss of work activities and social connections on the quality of life of people with intellectual disabilities. Providing social support to others may help people with intellectual disabilities to construct social valued roles, either in or outside the work situation. Professionals and employers can support people with intellectual disabilities to find opportunities to provide social support to others. It is important to invest in sustainable and innovative post-pandemic community participation initiatives and particularly in accessible post-pandemic employment support, for example by organising paid in-company training placements. It is essential that professionals support people with intellectual disabilities to enhance their sources of resilience and coping strategies, that may have diminished as a result of the pandemic
Edge detection versus densitometry in the quantitative assessment of stenosis phantoms: an in vivo comparison in procine coronary arteries
The aim of this study was the in vivo validation and comparison of the geometric and densitometric technique of a computer-assisted automatic quantitative angiographic system (CAAS system). In six Landrace Yorkshire pigs (45 to 55 kg), precision-drilled phantoms with a circular lumen of 0.5, 0.7, 1.0, 1.4, and 1.9 mm were percutaneously introduced into the left anterior descending or left circumflex coronary artery. Twenty-eight coronary angiograms obtained with the phantom in a wedged intracoronary position could be quantitatively analyzed. Minimal lumen diameter, minimal cross-sectional area, percent diameter stenosis, and cross-sectional area stenosis were automatically measured with both the geometric and densitometric technique and were compared with the known phantom dimensions. When minimal lumen diameter was measured using the geometric approach, a nonsignificant underestimation of the phantom size was observed, with a mean difference of -0.06 +/- 0.14 mm. The larger mean difference observed with videodensitometry (-0.11 +/- 0.20 mm) was the result of the failure of the technique to differentiate the low lumen videodensities of two phantoms of smaller size (0.5 and 0.7 mm) from a dense background. Percent cross-sectional area stenosis measured with the two techniques showed a good correlation with the corresponding phantom measurements (mean difference between percent cross-sectional area stenosis calculated from the quantitative angiographic measurements and the corresponding phantom dimensions was equal to 2 +/- 6% for both techniques, correlation coefficient = 0.93 with both techniques, SEE = 5% with the geometric technique and 6% with the densitometric approach).(ABSTRACT TRUNCATED AT 250 WORDS
Improved stability regions for ground states of the extended Hubbard model
The ground state phase diagram of the extended Hubbard model containing
nearest and next-to-nearest neighbor interactions is investigated in the
thermodynamic limit using an exact method. It is found that taking into account
local correlations and adding next-to-nearest neighbor interactions both have
significant effects on the position of the phase boundaries. Improved stability
domains for the -pairing state and for the fully saturated ferromagnetic
state at half filling have been constructed. The results show that these states
are the ground states for model Hamiltonians with realistic values of the
interaction parameters.Comment: 21 pages (10 figures are included) Revtex, revised version. To be
published in Phys. Rev. B. E-mail: [email protected]
Social learning in multilevel flood risk governance: Lessons from the Dutch Room for the River Program
Although social learning is a key element of multilevel flood risk governance, it is hardly studied. This paper addresses this knowledge gap. The paper aims to identify enabling conditions for social learning in multilevel flood risks governance arrangements.We first conceptualize social learning and draw up a conceptual framework consisting of enabling conditions for social learning, using the literature on adaptive co-management, sustainable land and water management, and integrated flood risk management. Next, we apply this framework to analyze social learning in the context of the Dutch Room for the River program. Our interview results reveal that social learning about integrated flood protection measures took place at multiple levels. We found that a strong personal commitment to learning and mutual interpersonal trust in working groups are key conditions for successful social learning. Based on our analysis, we conclude with some recommendations for enhancing social learning processes in future flood protection programs
Increasing morphological disparity and decreasing optimality for jaw speed and strength during the radiation of jawed vertebrates
The Siluro-Devonian adaptive radiation of jawed vertebrates, which underpins almost all living vertebrate biodiversity, is characterized by the evolutionary innovation of the lower jaw. Multiple lines of evidence have suggested that the jaw evolved from a rostral gill arch, but when the jaw took on a feeding function remains unclear. We quantified the variety of form in the earliest jaws in the fossil record from which we generated a theoretical morphospace that we then tested for functional optimality. By drawing comparisons with the real jaw data and reconstructed jaw morphologies from phylogenetically inferred ancestors, our results show that the earliest jaw shapes were optimized for fast closure and stress resistance, inferring a predatory feeding function. Jaw shapes became less optimal for these functions during the later radiation of jawed vertebrates. Thus, the evolution of jaw morphology has continually explored previously unoccupied morphospace and accumulated disparity through time, laying the foundation for diverse feeding strategies and the success of jawed vertebrates
In vivo imaging of brain androgen receptors in rats: a [18F]FDHT PET study
AbstractIntroductionSteroid hormones like androgens play an important role in the development and maintenance of several brain functions. Androgens can act through androgen receptors (AR) in the brain. This study aims to demonstrate the feasibility of positron emission tomography (PET) with 16β-[18F]fluoro-5α-dihydrotestosterone ([18F]FDHT) to image AR expression in the brain.MethodsMale Wistar rats were either orchiectomized to inhibit endogenous androgen production or underwent sham-surgery. Fifteen days after surgery, rats were subjected to a 90-min dynamic [18F]FDHT PET scan with arterial blood sampling. In a subset of orchiectomized rats, 1mg/kg dihydrotestosterone was co-injected with the tracer in order to saturate the AR. Plasma samples were analyzed for the presence of radioactive metabolites by radio-TLC. Pharmacokinetic modeling was performed to quantify brain kinetics of the tracer. After the PET scan, the animals were terminated for ex-vivo biodistribution.ResultsPET imaging and ex vivo biodistribution studies showed low [18F]FDHT uptake in all brain regions, except pituitary. [18F]FDHT uptake in the surrounding cranial bones was high and increased over time. [18F]FDHT was rapidly metabolized in rats. Metabolism was significantly faster in orchiectomized rats than in sham-orchiectomized rats. Quantitative analysis of PET data indicated substantial spill-over of activity from cranial bones into peripheral brain regions, which prevented further analysis of peripheral brain regions. Logan graphical analysis and kinetic modeling using 1- and 2-tissue compartment models showed reversible and homogenously distributed tracer uptake in central brain regions. [18F]FDHT uptake in the brain could not be blocked by endogenous androgens or administration of dihydrotestosterone.ConclusionThe results of this study indicate that imaging of AR availability in rat brain with [18F]FDHT PET is not feasible. The low AR expression in the brain, the rapid metabolism of [18F]FDHT in rats and the poor brain penetration of the tracer likely contributed to the poor performance of [18F]FDHT PET in this study
Paraprofessionals for anxiety and depressive disorders
Background The established mental health care system does not have the resources to meet the extensive need for care of those with anxiety and depressive disorders. Paraprofessionals partially replacing professionals may be cost-effective. Objectives To investigate the effectiveness of any kind of psychological treatment for anxiety and depressive disorders performed by paraprofessionals compared with professionals, waiting list or placebo condition. To examine whether the results apply to clinically significant anxiety and depressive disorders of referred patients with a psychiatric history and/or whose illness has lasted two years or more. Search strategy CCDANCTR-Studies using the following terms: (paraprofessional* or para-professional* or non-professional* or non-professional* or peer or volunt*); EMBASE (ExerptaMedica), MEDLINE and PsycINFO, all years published, key words: para-/paraprofessional, non-/nonprofessional, rand*, respectively psy*; citation lists of articles reviewing the subject and included studies; correspondence with authors of controlled studies and review reports on the subject. Selection criteria Randomised controlled trials that used symptom measures, and compared the effects of psychological treatments given by paraprofessionals (mental health care workers, paid or voluntary, unqualified with respect to the psychological treatment) with psychological treatments given by professionals, and with waiting list or placebo condition. Data collection and analysis The standard mean difference was used to pool continuous data from each trial, and odds ratios were used to pool dichotomous data, using a random effects model. The generic inverse variance method was used for combining continuous and dichotomous data. The effect of low quality studies and the use of self-rated versus observer-rated measures were tested, and subgroup analyses were performed for differences between depression and anxiety diagnosis, paraprofessionals with/without professional background, group/individual intervention, length of follow-up and gender (post-hoc subgroup analysis). Main results Five studies, all using self-report measures, reported five comparisons of paraprofessionals versus professionals (n=106) and five comparisons of paraprofessionals versus control condition (n=220). No differences were found between paraprofessionals and professionals (SMD=0.09, 95% CI -0.23 to 0.40, p=0.58; no significant heterogeneity). Studies comparing paraprofessionals versus control reported mixed continuous and dichotomous data showed a significant pooled effect in favour of paraprofessionals (OR=0.34, 95% CI 0.13 to 0.88, p=0.03), but heterogeneity was indicated (I-2=60.9%, Chi(2)=10.24, df=4, p=0.04). After correction for heterogeneity and removing one study of low quality, the pooling of data from three studies (n=128; mixed gender and women only) indicated no significant difference in effect between paraprofessionals and professionals (SMD=0.13, 95% CI -0.39 to 0.64; p=0.63) and a strongly significant pooled effect for three studies (n=188; women only) favouring paraprofessionals over the control condition (OR=0.30, 95% CI 0.18 to 0.48, p Authors' conclusions The few studies included in the review did not allow conclusions about the effect of paraprofessionals compared to professionals. Pooling data from three studies, involving women only, indicated a significant effect for paraprofessionals (all volunteers) compared to no treatment. The evidence to date may justify the development and evaluation of programs incorporating paraprofessionals in treatment programs for anxiety and depressive disorders
Attacks on quantum key distribution protocols that employ non-ITS authentication
We demonstrate how adversaries with unbounded computing resources can break
Quantum Key Distribution (QKD) protocols which employ a particular message
authentication code suggested previously. This authentication code, featuring
low key consumption, is not Information-Theoretically Secure (ITS) since for
each message the eavesdropper has intercepted she is able to send a different
message from a set of messages that she can calculate by finding collisions of
a cryptographic hash function. However, when this authentication code was
introduced it was shown to prevent straightforward Man-In-The-Middle (MITM)
attacks against QKD protocols.
In this paper, we prove that the set of messages that collide with any given
message under this authentication code contains with high probability a message
that has small Hamming distance to any other given message. Based on this fact
we present extended MITM attacks against different versions of BB84 QKD
protocols using the addressed authentication code; for three protocols we
describe every single action taken by the adversary. For all protocols the
adversary can obtain complete knowledge of the key, and for most protocols her
success probability in doing so approaches unity.
Since the attacks work against all authentication methods which allow to
calculate colliding messages, the underlying building blocks of the presented
attacks expose the potential pitfalls arising as a consequence of non-ITS
authentication in QKD-postprocessing. We propose countermeasures, increasing
the eavesdroppers demand for computational power, and also prove necessary and
sufficient conditions for upgrading the discussed authentication code to the
ITS level.Comment: 34 page
Practical free-start collision attacks on 76-step SHA-1
In this paper we analyze the security of the compression function
of SHA-1 against collision attacks, or equivalently free-start collisions
on the hash function. While a lot of work has been dedicated to the analysis
of SHA-1 in the past decade, this is the first time that free-start collisions
have been considered for this function. We exploit the additional
freedom provided by this model by using a new start-from-the-middle
approach in combination with improvements on the cryptanalysis tools
that have been developed for SHA-1 in the recent years. This results in
particular in better differential paths than the ones used for hash function
collisions so far. Overall, our attack requires about evaluations
of the compression function in order to compute a one-block free-start
collision for a 76-step reduced version, which is so far the highest number
of steps reached for a collision on the SHA-1 compression function.
We have developed an efficient GPU framework for the highly branching
code typical of a cryptanalytic collision attack and used it in an optimized
implementation of our attack on recent GTX 970 GPUs. We report
that a single cheap US\$ 350 GTX 970 is sufficient to find the collision in
less than 5 days. This showcases how recent mainstream GPUs seem to
be a good platform for expensive and even highly-branching cryptanalysis
computations. Finally, our work should be taken as a reminder that
cryptanalysis on SHA-1 continues to improve. This is yet another proof
that the industry should quickly move away from using this function
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