1,058 research outputs found
Annual Research Review: An expanded account of information-processing mechanisms in risk for child and adolescent anxiety and depression
Background: Anxiety and depression occurring during childhood and adolescence are common and costly. While
early-emerging anxiety and depression can arise through a complex interplay of ‘distal’ factors such as genetic and
environmental influences, temperamental characteristics and brain circuitry, the more proximal mechanisms that
transfer risks on symptoms are poorly delineated. Information-processing biases, which differentiate youth with and
without anxiety and/or depression, could act as proximal mechanisms that mediate more distal risks on symptoms.
This article reviews the literature on information-processing biases, their associations with anxiety and depression
symptoms in youth and with other distal risk factors, to provide direction for further research. Methods: Based on
strategic searches of the literature, we consider how youth with and without anxiety and/or depression vary in how
they deploy attention to social-affective stimuli, discriminate between threat and safety cues, retain memories of
negative events and appraise ambiguous information. We discuss how these information-processing biases are
similarly or differentially expressed on anxiety and depression and whether these biases are linked to genetic and
environmental factors, temperamental characteristics and patterns of brain circuitry functioning implicated in
anxiety and depression. Findings: Biases in attention and appraisal characterise both youth anxiety and depression
but with some differences in how these are expressed for each symptom type. Difficulties in threat-safety cue
discrimination characterise anxiety and are understudied in depression, while biases in the retrieval of negative and
overgeneral memories have been observed in depression but are understudied in anxiety. Information-processing
biases have been studied in relation to some distal factors but not systematically, so relationships remain
inconclusive. Conclusions: Biases in attention, threat-safety cue discrimination, memory and appraisal may
characterise anxiety and/or depression risk. We discuss future research directions that can more systematically test
whether these biases act as proximal mechanisms that mediate other distal risk factors. Keywords: Anxiety;
depression; risk factors.Full Tex
D-cycloserine augmentation of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders: a systematic review and meta-analysis of individual participant data
Importance: Whether and under which conditions D-cycloserine (DCS) augments the effects of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders is unclear. Objective: To clarify whether DCS is superior to placebo in augmenting the effects of cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders and to evaluate whether antidepressants interact with DCS and the effect of potential moderating variables. Data Sources: PubMed, EMBASE, and PsycINFO were searched from inception to February 10, 2016. Reference lists of previous reviews and meta-analyses and reports of randomized clinical trials were also checked. Study Selection: Studies were eligible for inclusion if they were (1) double-blind randomized clinical trials of DCS as an augmentation strategy for exposure-based cognitive behavior therapy and (2) conducted in humans diagnosed as having specific phobia, social anxiety disorder, panic disorder with or without agoraphobia, obsessive-compulsive disorder, or posttraumatic stress disorder. Data Extraction and Synthesis: Raw data were obtained from the authors and quality controlled. Data were ranked to ensure a consistent metric across studies (score range, 0-100). We used a 3-level multilevel model nesting repeated measures of outcomes within participants, who were nested within studies. Results: Individual participant data were obtained for 21 of 22 eligible trials, representing 1047 of 1073 eligible participants. When controlling for antidepressant use, participants receiving DCS showed greater improvement from pretreatment to posttreatment (mean difference, -3.62; 95% CI, -0.81 to -6.43; P = .01; d = -0.25) but not from pretreatment to midtreatment (mean difference, -1.66; 95% CI, -4.92 to 1.60; P = .32; d = -0.14) or from pretreatment to follow-up (mean difference, -2.98, 95% CI, -5.99 to 0.03; P = .05; d = -0.19). Additional analyses showed that participants assigned to DCS were associated with lower symptom severity than those assigned to placebo at posttreatment and at follow-up. Antidepressants did not moderate the effects of DCS. None of the prespecified patient-level or study-level moderators was associated with outcomes. Conclusions and Relevance: D-cycloserine is associated with a small augmentation effect on exposure-based therapy. This effect is not moderated by the concurrent use of antidepressants. Further research is needed to identify patient and/or therapy characteristics associated with DCS response.2018-05-0
A Novel Universal Corner Module for Urban Electric Vehicles: Design, Prototype, and Experiment
This thesis presents the work of creating and validating a novel corner module for a three-wheeled urban electric vehicle in the tadpole configuration. As the urban population increases, there will be a growing need for compact, personal transportation. While urban electric vehicles are compact, they are inherently less stable when negotiating a turn, and they leave little space for passengers, cargo and crash structures. Corner modules provide an effective solution to increase the space in the cabin and increase the handling capabilities of the vehicle.
Many corner module designs have been produced in the hopes of increasing the cabin space and improving the road holding capabilities of the wheel. However, none have been used to increase the turning stability of the vehicle via an active camber mechanism while remaining in an acceptable packaging space. Active camber mechanisms are also not a new concept, but they have not been implemented in a narrow packaging space with relatively large camber angle.
Parallel mechanism research and vehicle dynamics theory were combined to generate and analyse this new corner module design. The corner module increases the stability of the urban electric vehicle by cambering the front wheels to -15 degrees when the vehicle is turning. The camber angle augmentation increases the track width which subsequently decreases the center of gravity height. These changes accumulated to increase the stability of the vehicle. The corner module uses two actuators to control the orientation of the wheel. Bias ply tires are incorporated into the corner module to enable the large camber angles. To increase the space in the cabin, the front left and right wheels are not connected by a mechanical linkage, and the motors are mounted to the wheel rim. While disc brakes are integrated into the corner module, the motor is also capable of regenerative braking.
By integrating this corner module into urban electric vehicles, the vehicle size and pollution can be reduced while increasing the cabin space and public space
Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.
BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 × coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution
Statistical modeling of earthquake damage
The purpose of this study was to build a statistical model of the economic damage that arises from earthquakes in order to better predict losses from future earthquakes. Though earthquakes are essentially a random event and cannot be fully anticipated, analyzing historical data and creating a statistical model can provide researchers with a more accurate estimate of future losses. The data set from which this model was built incorporated earthquakes occurring worldwide from 1915-2015 in which the total damage was recorded. The final model was a multiple linear regression model explaining total damage resulting from an earthquake through four independent variables: whether or not a tsunami occurred (tsunami_dummy), whether or not the earthquake occurred in a developed nation (developed_dummy), intensity (intensity), and number of injuries (total_injuries). Statisticians, specifically those at insurance companies, can use these results to provide rough estimates of potential losses after an earthquake occurs. This model is just a starting point for statisticians, however; more accurate and representative models can be created from insurance companies’ historical losses in order to better estimate future losses
Decentralizing Attribute-Based Encryption
We propose a Multi-Authority Attribute-Based Encryption (ABE) system.
In our system, any party can become an authority and there is no
requirement for any global coordination other than the creation of an
initial set of common reference parameters. A party can simply act as
an ABE authority by creating a public key and issuing private keys to
different users that reflect their attributes. A user can encrypt
data in terms of any boolean formula over attributes issued from any
chosen set of authorities. Finally, our system does not require any
central authority.
In constructing our system, our largest technical hurdle is to make it collusion resistant. Prior Attribute-Based Encryption systems achieved collusion resistance when the ABE system authority ``tied\u27\u27 together different components (representing different attributes) of a user\u27s private key by randomizing the key. However, in our system each component will come from a potentially different authority, where we assume no coordination between such authorities. We create new techniques to tie key components together and prevent collusion attacks between users with different global identifiers.
We prove our system secure using the recent dual system encryption
methodology where the security proof works by first converting the
challenge ciphertexts and private keys to a semi-functional form and
then arguing security. We follow a recent variant of the dual system
proof technique due to Lewko and Waters and build our system using
bilinear groups of composite order. We prove security under similar
static assumptions to the LW paper in the random oracle model
Low-mass pre--main-sequence stars in the Magellanic Clouds
[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar
stars form in very large numbers. Most attractive places for catching low-mass
star formation in the act are young stellar clusters and associations, still
(half-)embedded in star-forming regions. The low-mass stars in such regions are
still in their pre--main-sequence (PMS) evolutionary phase. The peculiar nature
of these objects and the contamination of their samples by the evolved
populations of the Galactic disk impose demanding observational techniques for
the detection of complete numbers of PMS stars in the Milky Way. The Magellanic
Clouds, the companion galaxies to our own, demonstrate an exceptional star
formation activity. The low extinction and stellar field contamination in
star-forming regions of these galaxies imply a more efficient detection of
low-mass PMS stars than in the Milky Way, but their distance from us make the
application of special detection techniques unfeasible. Nonetheless, imaging
with the Hubble Space Telescope yield the discovery of solar and sub-solar PMS
stars in the Magellanic Clouds from photometry alone. Unprecedented numbers of
such objects are identified as the low-mass stellar content of their
star-forming regions, changing completely our picture of young stellar systems
outside the Milky Way, and extending the extragalactic stellar IMF below the
persisting threshold of a few solar masses. This review presents the recent
developments in the investigation of PMS stars in the Magellanic Clouds, with
special focus on the limitations by single-epoch photometry that can only be
circumvented by the detailed study of the observable behavior of these stars in
the color-magnitude diagram. The achieved characterization of the low-mass PMS
stars in the Magellanic Clouds allowed thus a more comprehensive understanding
of the star formation process in our neighboring galaxies.Comment: Review paper, 26 pages (in LaTeX style for Springer journals), 4
figures. Accepted for publication in Space Science Review
Revocation Systems with Very Small Private Keys
In this work, we design a method for creating public key broadcast
encryption systems. Our main technical innovation is based
on a new ``two equation\u27\u27 technique for revoking users. This technique
results in two key contributions:
First, our new scheme has ciphertext size overhead ,
where is the number of revoked users, and the size of public and
private keys is only a \emph{constant} number of group elements from
an elliptic-curve group of prime order. In addition, the public key allows
us to encrypt to an unbounded number of users. Our system is the first to
achieve such parameters. We give two versions of our scheme: a simpler version which we prove to be selectively secure in the standard model under a new, but non-interactive assumption, and another version that employs the new dual system encryption technique of Waters to obtain adaptive security under the d-BDH and decisional Linear assumptions.
Second, we show that our techniques can be used to realize
Attribute-Based Encryption (ABE) systems with non-monotonic access
formulas, where our key storage is significantly more efficient than
previous solutions.
This result is also proven selectively secure in the standard model under our new non-interactive assumption.
We believe that our new technique will be of use elsewhere as well
How to Leak on Key Updates
In the continual memory leakage model, security against attackers who can repeatedly obtain leakage is achieved by periodically updating the secret key. This is an appealing model which captures a wide class of side-channel attacks, but all previous constructions in this model provide only a very minimal amount of leakage tolerance \emph{during secret key updates}. Since key updates may happen frequently, improving security guarantees against attackers who obtain leakage during these updates is an important problem. In this work, we present the first cryptographic primitives which are secure against a super-logarithmic amount of leakage during secret key updates. We present signature and public key encryption schemes in the standard model which can tolerate a constant fraction of the secret key to be leaked between updates as well as \emph{a constant fraction of the secret key and update randomness} to be leaked during updates. Our signature scheme also allows us to leak a constant fraction of the entire secret state during signing. Before this work, it was unknown how to tolerate super-logarithmic leakage during updates even in the random oracle model. We rely on subgroup decision assumptions in composite order bilinear groups
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