Highlights • Sex differences in cognitive abilities are changing and vary across nations. • Some differences are found in infancy but depend on task characteristics. • Fraternal-twin studies help ...establish the role of prenatal androgens. • International data help explain the role of economic prosperity and gender equity. • Modifying biological and environmental factors could maximize cognitive potential.
We analyze energy consumption in optical modulators operated in depletion and intended for low-power interconnect applications. We include dynamic dissipation from charging modulator capacitance and ...net energy consumption from absorption and photocurrent, both in reverse and small forward bias. We show that dynamic dissipation can be independent of static bias, though only with specific kinds of bias circuits. We derive simple expressions for the effects of photocurrent on energy consumption, valid in both reverse and small forward bias. Though electroabsorption modulators with large reverse bias have substantial energy penalties from photocurrent dissipation, we argue that modulator diodes with thin depletion regions and operating in small reverse and/or forward bias could have little or no such photocurrent energy penalty, even conceivably being more energy-efficient than an ideal loss-less modulator.
This meta-analysis, spanning 5 decades of Draw-A-Scientist studies, examined U.S. children's gender-science stereotypes linking science with men. These stereotypes should have weakened over time ...because women's representation in science has risen substantially in the United States, and mass media increasingly depict female scientists. Based on 78 studies (N = 20,860; grades K-12), children's drawings of scientists depicted female scientists more often in later decades, but less often among older children. Children's depictions of scientists therefore have become more gender diverse over time, but children still associate science with men as they grow older. These results may reflect that children observe more male than female scientists in their environments, even though women's representation in science has increased over time.
Summary The diagnosis of multiple sclerosis is based on neurological symptoms and signs, alongside evidence of dissemination of CNS lesions in space and time. MRI is often sufficient to confirm the ...diagnosis when characteristic lesions accompany a typical clinical syndrome, but in some patients, further supportive information is obtained from cerebrospinal fluid examination and neurophysiological testing. Differentiation is important from other diseases in which demyelination is a feature (eg, neuromyelitis optica spectrum disorder and acute disseminated encephalomyelitis) and from non-demyelinating disorders such as chronic small vessel disease and other inflammatory, granulomatous, infective, metabolic, and genetic causes that can mimic multiple sclerosis. Advances in MRI and serological and genetic testing have greatly increased accuracy in distinguishing multiple sclerosis from these disorders, but misdiagnosis can occur. In this Series paper we explore the progress and challenges in the diagnosis of multiple sclerosis with reference to diagnostic criteria, important differential diagnoses, controversies and uncertainties, and future prospects.
We propose a device that can take an arbitrary monochromatic input beam and, automatically and without any calculations, couple it into a single-mode guide or beam. Simple feedback loops from ...detectors to modulator elements allow the device to adapt to any specific input beam form. Potential applications include automatic compensation for misalignment and defocusing of an input beam, coupling of complex modes or multiple beams from fibers or free space to single-mode guides, and retaining coupling to a moving source. Straightforward extensions allow multiple different overlapping orthogonal input beams to be separated simultaneously to different single-mode guides with no splitting loss in principle. The approach is suitable for implementation in integrated optics platforms that offer elements such as phase shifters, Mach-Zehnder interferometers, grating couplers, and integrated monitoring detectors, and the basic approach is applicable in principle to other types of waves, such as microwaves or acoustics.
As atmospheric levels of CO(2) increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on ...either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO(2) conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification.
Can teaching students about brain plasticity improve their grades? A recent large, national experiment (Yeager et al.) found that a brief growth mindset intervention improved lower-achieving ...adolescents’ grades by 0.10 points. Debate about interpreting the study’s findings illustrates the need to consider effect heterogeneity and contextual factors when evaluating effect sizes.
The United States government is encouraging physicians to adopt patient portals-secure websites that allow patients to access their health information. For patient portals to recognize their full ...potential and improve patient care, health care providers' acceptance and encouragement of their use will be essential. However, little is known about provider concerns or views of patient portals.
We conducted this qualitative study to determine how administrators, clinic staff, and health care providers at practices serving a lower income adult population viewed patient portals in terms of their potential benefit, areas of concern, and hopes for the future.
We performed in-depth interviews between October 2013 and June 2014 with 20 clinic personnel recruited from health centers in four North Carolina counties. Trained study personnel conducted individual interviews following an interviewer guide to elicit perceptions of the benefits and disadvantages of patient portals. Interviews were recorded and transcribed. Research team members reviewed transcribed interviews for major themes to construct a coding dictionary. Two researchers then coded each transcript with any coding discrepancies resolved through discussion.
The interviews revealed that clinic personnel viewed patient portals as a mandated product that had potential to improve communication and enhance information sharing. However, they expressed many concerns including portals' potential to generate more work, confuse patients, alienate non-users, and increase health disparities. Clinic personnel expected few older and disadvantaged patients to use a portal.
Given that clinic personnel have significant concerns about portals' unintended consequences, their uptake and impact on care may be limited. Future studies should examine ways portals can be implemented in practices to address providers' concerns and meet the needs of vulnerable populations.
We examine the current performance and future demands of interconnects to and on silicon chips. We compare electrical and optical interconnects and project the requirements for optoelectronic and ...optical devices if optics is to solve the major problems of interconnects for future high-performance silicon chips. Optics has potential benefits in interconnect density, energy, and timing. The necessity of low interconnect energy imposes low limits especially on the energy of the optical output devices, with a ~ 10 fJ/bit device energy target emerging. Some optical modulators and radical laser approaches may meet this requirement. Low (e.g., a few femtofarads or less) photodetector capacitance is important. Very compact wavelength splitters are essential for connecting the information to fibers. Dense waveguides are necessary on-chip or on boards for guided wave optical approaches, especially if very high clock rates or dense wavelength-division multiplexing (WDM) is to be avoided. Free-space optics potentially can handle the necessary bandwidths even without fast clocks or WDM. With such technology, however, optics may enable the continued scaling of interconnect capacity required by future chips.
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