71 research outputs found
Anisotropic magnetoresistance of spin-orbit coupled carriers scattered from polarized magnetic impurities
Anisotropic magnetoresistance (AMR) is a relativistic magnetotransport
phenomenon arising from combined effects of spin-orbit coupling and broken
symmetry of a ferromagnetically ordered state of the system. In this work we
focus on one realization of the AMR in which spin-orbit coupling enters via
specific spin-textures on the carrier Fermi surfaces and ferromagnetism via
elastic scattering of carriers from polarized magnetic impurities. We report
detailed heuristic examination, using model spin-orbit coupled systems, of the
emergence of positive AMR (maximum resistivity for magnetization along
current), negative AMR (minimum resistivity for magnetization along current),
and of the crystalline AMR (resistivity depends on the absolute orientation of
the magnetization and current vectors with respect to the crystal axes)
components. We emphasize potential qualitative differences between pure
magnetic and combined electro-magnetic impurity potentials, between short-range
and long-range impurities, and between spin-1/2 and higher spin-state carriers.
Conclusions based on our heuristic analysis are supported by exact solutions to
the integral form of the Boltzmann transport equation in archetypical
two-dimensional electron systems with Rashba and Dresselhaus spin-orbit
interactions and in the three-dimensional spherical Kohn-Littinger model. We
include comments on the relation of our microscopic calculations to standard
phenomenology of the full angular dependence of the AMR, and on the relevance
of our study to realistic, two-dimensional conduction-band carrier systems and
to anisotropic transport in the valence band of diluted magnetic
semiconductors.Comment: 15 pages, Kohn-Littinger model adde
Anxiety and Depression in Adults with Autism Spectrum Disorder: A Systematic Review and Meta-analysis
Adults with autism spectrum disorder (ASD) are thought to be at disproportionate risk of developing mental health comorbidities, with anxiety and depression being considered most prominent amongst these. Yet, no systematic review has been carried out to date to examine rates of both anxiety and depression focusing specifically on adults with ASD. This systematic review and meta-analysis examined the rates of anxiety and depression in adults with ASD and the impact of factors such as assessment methods and presence of comorbid intellectual disability (ID) diagnosis on estimated prevalence rates. Electronic database searches for studies published between January 2000 and September 2017 identified a total of 35 studies, including 30 studies measuring anxiety (n = 26 070; mean age = 30.9, s.d. = 6.2 years) and 29 studies measuring depression (n = 26 117; mean age = 31.1, s.d. = 6.8 years). The pooled estimation of current and lifetime prevalence for adults with ASD were 27% and 42% for any anxiety disorder, and 23% and 37% for depressive disorder. Further analyses revealed that the use of questionnaire measures and the presence of ID may significantly influence estimates of prevalence. The current literature suffers from a high degree of heterogeneity in study method and an overreliance on clinical samples. These results highlight the importance of community-based studies and the identification and inclusion of well-characterized samples to reduce heterogeneity and bias in estimates of prevalence for comorbidity in adults with ASD and other populations with complex psychiatric presentations
Centering inclusivity in the design of online conferences: An OHBM-Open Science perspective
As the global health crisis unfolded, many academic conferences moved online in 2020. This move has been hailed as a positive step towards inclusivity in its attenuation of economic, physical, and legal barriers and effectively enabled many individuals from groups that have traditionally been underrepresented to join and participate. A number of studies have outlined how moving online made it possible to gather a more global community and has increased opportunities for individuals with various constraints, e.g., caregiving responsibilities. Yet, the mere existence of online conferences is no guarantee that everyone can attend and participate meaningfully. In fact, many elements of an online conference are still significant barriers to truly diverse participation: the tools used can be inaccessible for some individuals; the scheduling choices can favour some geographical locations; the set-up of the conference can provide more visibility to well-established researchers and reduce opportunities for early-career researchers. While acknowledging the benefits of an online setting, especially for individuals who have traditionally been underrepresented or excluded, we recognize that fostering social justice requires inclusivity to actively be centered in every aspect of online conference design. Here, we draw from the literature and from our own experiences to identify practices that purposefully encourage a diverse community to attend, participate in, and lead online conferences. Reflecting on how to design more inclusive online events is especially important as multiple scientific organizations have announced that they will continue offering an online version of their event when in-person conferences can resume
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Outcomes of treatment of neovascular glaucoma with intravitreal bevacizumab
To evaluate the course of treatment and outcomes of neovascular glaucoma (NVG) treated with intravitreal bevacizumab.
The study is a retrospective, non-comparative, consecutive, interventional case series. Demographic data, past ocular history, cause of NVG and anterior chamber angle status were recorded. Visual acuity (VA), intraocular pressure (IOP), number of IOP-lowering medications and type of treatment administered were recorded at the time of NVG diagnosis and at follow-up intervals. Treatment-related complications and reasons for vision loss were recorded.
The study included 56 eyes of 52 patients. At the time of NVG diagnosis, the median VA was count fingers, and the mean IOP (SD) was 40 (11) mm Hg. At 6 months after initial bevacizumab injection, the median VA was 1/200, and the mean IOP (SD) was 18 (15) mm Hg. Seventy-one per cent of eyes underwent panretinal photocoagulation after NVG diagnosis. Sixty-one per cent of eyes received a glaucoma drainage implant (GDI). The Kaplan-Meier cumulative proportion of eyes with open angles receiving a GDI after initial bevacizumab injection was not statistically significantly different from that of eyes with closed angles. Forty-six per cent of eyes received repeat bevacizumab injections. Eleven eyes had hyphaema after both bevacizumab injection and GDI surgery, while three eyes had hyphaema after GDI surgery but prior to initial bevacizumab injection.
Intravitreal bevacizumab is now a frequently used adjunct for the treatment of NVG. Eyes must be monitored closely after initial injection of intravitreal bevacizumab, regardless of initial angle status, as many may still require surgery to lower IOP or repeat injections of intravitreal bevacizumab
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