4,204 research outputs found
Loneliness in autistic adults: A systematic review
In this systematic review, we examined quantitative, qualitative and mixed methods studies on loneliness in autistic adults. A total of 1460 articles were identified, and 34 of these met inclusion criteria. Results demonstrated that (1) there is a paucity of qualitative data providing first-hand descriptions of loneliness from autistic adults; (2) few empirical studies have used reliable/valid measures of loneliness developed specifically for autistic adults, and in just one study was a measure of loneliness developed for, and validated in, autistic adults; (3) the collective dimension of loneliness (i.e. belonging in society) has been described by autistic adults, yet has not been investigated as frequently as the intimate (i.e. romantic relationships) or relational (i.e. friend/family relationships) dimensions of loneliness; (4) the factors associated with increased loneliness in autistic adults include autistic characteristics, anxiety, depression and suicidal ideation, negative experiences and learned helplessness, a lack of autism understanding and acceptance, sensory avoidance, camouflaging and unemployment; and (5) the factors associated with decreased loneliness in autistic adults include having relationships, participation in social skill interventions and/or experiencing fewer difficulties with social skills, positive views and acceptance of oneself, being female and time spent engaging in activities (e.g. online gaming). Directions for future research are considered
Conservation of Nonsense-Mediated mRNA Decay Complex Components Throughout Eukaryotic Evolution
Nonsense-mediated mRNA decay (NMD) is an essential eukaryotic process regulating transcript quality and abundance, and is involved in diverse processes including brain development and plant defenses. Although some of the NMD machinery is conserved between kingdoms, little is known about its evolution. Phosphorylation of the core NMD component UPF1 is critical for NMD and is regulated in mammals by the SURF complex (UPF1, SMG1 kinase, SMG8, SMG9 and eukaryotic release factors). However, since SMG1 is reportedly missing from the genomes of fungi and the plant Arabidopsis thaliana, it remains unclear how UPF1 is activated outside the metazoa. We used comparative genomics to determine the conservation of the NMD pathway across eukaryotic evolution. We show that SURF components are present in all major eukaryotic lineages, including fungi, suggesting that in addition to UPF1 and SMG1, SMG8 and SMG9 also existed in the last eukaryotic common ancestor, 1.8 billion years ago. However, despite the ancient origins of the SURF complex, we also found that SURF factors have been independently lost across the Eukarya, pointing to genetic buffering within the essential NMD pathway. We infer an ancient role for SURF in regulating UPF1, and the intriguing possibility of undiscovered NMD regulatory pathways
The TOPLESS corepressor regulates developmental switches in the bryophyte Physcomitrium patens that were critical for plant terrestrialisation
The plant-specific TOPLESS (TPL) family of transcriptional corepressors is integral to multiple angiosperm developmental processes. Despite this, we know little about TPL function in other plants. To address this gap, we investigated the roles TPL plays in the bryophyte Physcomitrium patens, which diverged from angiosperms approximately 0.5 billion years ago. Although complete loss of PpTPL function is lethal, transgenic lines with reduced PpTPL activity revealed that PpTPLs are essential for two fundamental developmental switches in this plant: the transitions from basal photosynthetic filaments (chloronemata) to specialised foraging filaments (caulonemata) and from two-dimensional (2D) to three-dimensional (3D) growth. Using a transcriptomics approach, we integrated PpTPL into the regulatory network governing 3D growth and we propose that PpTPLs represent another important class of regulators that are essential for the 2D-to-3D developmental switch. Transcriptomics also revealed a previously unknown role for PpTPL in the regulation of flavonoids. Intriguingly, 3D growth and the formation of caulonemata were crucial innovations that facilitated the colonisation of land by plants, a major transformative event in the history of life on Earth. We conclude that TPL, which existed before the land plants, was co-opted into new developmental pathways, enabling phytoterrestrialisation and the evolution of land plants
Computational and Biological Analogies for Understanding Fine-Tuned Parameters in Physics
In this philosophical paper, we explore computational and biological
analogies to address the fine-tuning problem in cosmology. We first clarify
what it means for physical constants or initial conditions to be fine-tuned. We
review important distinctions such as the dimensionless and dimensional
physical constants, and the classification of constants proposed by
Levy-Leblond. Then we explore how two great analogies, computational and
biological, can give new insights into our problem. This paper includes a
preliminary study to examine the two analogies. Importantly, analogies are both
useful and fundamental cognitive tools, but can also be misused or
misinterpreted. The idea that our universe might be modelled as a computational
entity is analysed, and we discuss the distinction between physical laws and
initial conditions using algorithmic information theory. Smolin introduced the
theory of "Cosmological Natural Selection" with a biological analogy in mind.
We examine an extension of this analogy involving intelligent life. We discuss
if and how this extension could be legitimated.
Keywords: origin of the universe, fine-tuning, physical constants, initial
conditions, computational universe, biological universe, role of intelligent
life, cosmological natural selection, cosmological artificial selection,
artificial cosmogenesis.Comment: 25 pages, Foundations of Science, in pres
An XMM-Newton observation of the massive, relaxed galaxy cluster ClJ1226.9+3332 at z=0.89
A detailed X-ray analysis of an XMM-Newton observation of the high-redshift
(z=0.89) galaxy cluster ClJ1226.9+3332 is presented. The X-ray temperature is
found to be 11.5{+1.1}{-0.9}keV, the highest X-ray temperature of any cluster
at z>0.6. In contrast to MS1054-0321, the only other very hot cluster currently
known at z>0.8, ClJ1226.9+3332 features a relaxed X-ray morphology, and its
high overall gas temperature is not caused by one or several hot spots. The
system thus constitutes a unique example of a high redshift, high temperature,
relaxed cluster, for which the usual hydrostatic equilibrium assumption, and
the X-ray mass is most reliable. A temperature profile is constructed (for the
first time at this redshift) and is consistent with the cluster being
isothermal out to 45% of the virial radius. Within the virial radius
(corresponding to a measured overdensity of a factor of 200), a total mass of
(1.4+/-0.5)*10^15 M_solar is derived, with a gas mass fraction of 12+/-5%. The
bolometric X-ray luminosity is (5.3+/-0.2)*10^45 erg/s. The probabilities of
finding a cluster of this mass within the volume of the discovery X-ray survey
are 8*10^{-5} for Omega_M=1 and 0.64 for Omega_M=0.3, making Omega_M=1 highly
unlikely. The entropy profile suggests that entropy evolution is being
observed. The metal abundance (of Z=0.33{+0.14}{-0.10} Z_solar), gas mass
fraction, and gas distribution are consistent with those of local clusters;
thus the bulk of the metals were in place by z=0.89.Comment: 13 pages, 8 figures. Accepted for publication in MNRA
The problem of equilibration and the computation of correlation functions on a quantum computer
We address the question of how a quantum computer can be used to simulate
experiments on quantum systems in thermal equilibrium. We present two
approaches for the preparation of the equilibrium state on a quantum computer.
For both approaches, we show that the output state of the algorithm, after long
enough time, is the desired equilibrium. We present a numerical analysis of one
of these approaches for small systems. We show how equilibrium
(time)-correlation functions can be efficiently estimated on a quantum
computer, given a preparation of the equilibrium state. The quantum algorithms
that we present are hard to simulate on a classical computer. This indicates
that they could provide an exponential speedup over what can be achieved with a
classical device.Comment: 25 pages LaTex + 8 figures; various additional comments, results and
correction
Young children, gender and the heterosexual matrix
In this paper I consider the adult focus of current mainstream gender theory. I relate this to how the concept of the heterosexual matrix originates in a social contract which excludes children from civil society. I argue that this exclusion is problematic both for theoretical reasons and from the perspective of children themselves. I start by discussing the nature of the heterosexual matrix and its foundations. I consider the implications for participation which arise from being named as a child, how that affects children’s attempts to claim participation in civil society, and how this is related to children’s naming of themselves as gendered. I then briefly consider the possibility that, because of their exclusion, children might also be considered to be exempt from the heterosexual matrix. However, I argue, there is considerable evidence that children are actively sexual beings who also work hard to claim inclusion in local practices of heterosexuality. I end by suggesting that there are three key reasons for this: that the discourses of normative sexuality provide children with a language to express sexual feelings; that self-insertion in the heterosexual matrix is a way for children to claim rights to participation; and that taking up heterosexual formations is a means whereby children can experience the power of naming themselves as part of the social world
On the ability of spectroscopic SZ effect measurements to determine the temperature structure of galaxy clusters
(abridged) We explore in this paper the ability of spatially resolved
spectroscopic measurements of the SZ effect (SZE) to determine the temperature
profile of galaxy clusters. We derive a general formalism for the thermal SZE
in galaxy clusters with a non-uniform temperature profile that can be applied
to both cool-core clusters and non-cool core cluster with an isothermal or
non-isothermal temperature structure. We derive an inversion technique through
which the electron distribution function can be extracted from spectroscopic
SZE observations over a wide frequency range. We study the fitting procedure to
extract the cluster temperature from a set of simulated spatially resolved
spectroscopic SZE observations in different bands of the spectrum, from 100 to
450 GHz. The results of our analysis for three different cluster prototypes
(A2199 with a low-temperature cool core, Perseus with a relatively
high-temperature cool core, Ophiuchus with an isothermal temperature
distribution) provide both the required precision of the SZE observations and
the optimal frequency bands for a determination of the cluster temperature
similar or better than that obtainable from X-ray observations. The precision
of SZE-derived temperature is also discussed for the outer regions of clusters.
We also study the possibility to extract, from our method, the parameters
characterizing the non-thermal SZE spectrum of the relativistic plasma
contained in the lobes of radio galaxies as well as the spectrum of
relativistic electrons co-spatially distributed with the thermal plasma in
clusters with non-thermal phenomena. We find that the next generation SZE
experiments with spectroscopic capabilities can provide precise temperature
distribution measurements (...)Comment: Submitted to Astronomy & Astrophysic
Detecting Sunyaev-Zel'dovich clusters with PLANCK: I. Construction of all-sky thermal and kinetic SZ-maps
All-sky thermal and kinetic Sunyaev-Zel'dovich (SZ) maps are presented for
assessing how well the PLANCK-mission can find and characterise clusters of
galaxies, especially in the presence of primary anisotropies of the cosmic
microwave background (CMB) and various galactic and ecliptic foregrounds. The
maps have been constructed from numerical simulations of structure formation in
a standard LCDM cosmology and contain all clusters out to redshifts of z = 1.46
with masses exceeding 5e13 M_solar/h. By construction, the maps properly
account for the evolution of cosmic structure, the halo-halo correlation
function, the evolving mass function, halo substructure and adiabatic gas
physics. The velocities in the kinetic map correspond to the actual density
environment at the cluster positions. We characterise the SZ-cluster sample by
measuring the distribution of angular sizes, the integrated thermal and kinetic
Comptonisations, the source counts in the three relevant PLANCK-channels, and
give the angular power-spectra of the SZ-sky. While our results are broadly
consistent with simple estimates based on scaling relations and spherically
symmetric cluster models, some significant differences are seen which may
affect the number of cluster detectable by PLANCK.Comment: 14 pages, 16 figures, 3 tables, submitted to MNRAS, 05.Jul.200
Quantum Computation with Quantum Dots
We propose a new implementation of a universal set of one- and two-qubit
gates for quantum computation using the spin states of coupled single-electron
quantum dots. Desired operations are effected by the gating of the tunneling
barrier between neighboring dots. Several measures of the gate quality are
computed within a newly derived spin master equation incorporating decoherence
caused by a prototypical magnetic environment. Dot-array experiments which
would provide an initial demonstration of the desired non-equilibrium spin
dynamics are proposed.Comment: 12 pages, Latex, 2 ps figures. v2: 20 pages (very minor corrections,
substantial expansion), submitted to Phys. Rev.
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