Investigation of an optically induced superstrate plasma for tuning microstrip antennas

Optically induced electron-hole plasmas in silicon are used to perform radiation pattern tuning. The antenna is a slot loaded microstrip patch and the effect of illumination is shown to produce beam switching in the radiation patterns of certain modes while other modes are left unaffected. The structure is specifically designed to make the best use of currently available miniature laser sources to form a compact tunable package. Modelled and measured results for tuning of the radiation patterns and frequency response are presented. The effect of the losses incurred by the plasma along with the losses in the optically transparent ground plane are quantified in both simulation and measurement. This forms the basis for designing other types of optically tunable miniature antennas based on the structure presented

Detection of B-mode polarization at degree angular scales by BICEP2

We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around ℓ∼80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of ≈300  μKCMB√s . BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ΛCDM expectation in the range 305σ. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power ∼(5–10)× smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3σ significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7σ. The observed B-mode power spectrum is well fit by a lensed-ΛCDM+tensor theoretical model with tensor-to-scalar ratio r=0.20 +0.07 −0.05, with r=0 disfavored at 7.0σ. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets

Reconsidering the Gospel According to Group Studies: A Neuropsychological Case Study Approach to Schizophrenia

Original article can be found at: http://www.informaworld.com/smpp/title~content=t713659088 Copyright Informa / Taylor and Francis GroupIndividual patterns of performance on tests of: visual perception, language, executive function, memory, and face-processing, were examined in 10 schizophrenic patients who were preselected for having current WAIS IQ and premorbid NART IQ scores in the normal range. Although the patients showed some heterogeneity in the type, pervasiveness, and degree of cognitive impairment, a majority had severely impaired verbal recall and familiar face-naming. This contrasted with the low incidence and severity of impairment on tests of executive function, visual recall, recognition memory, naming, and unfamiliar faceprocessing. Contrasts between individual patients indicated that verbal recall and executive performance are independent in some patients and that memory appears to be the core deficit. The profile of impaired and preserved cognitive function revealed some important dissimilarities from the pattern that has emerged from group studies. Finally, face-naming correlated highly with the learning of unrelated paired associates, confirming a similarity with neurological patients who have person name anomia. It is suggested that both deficits might reflect a problem with learning ''meaninglessness'' associations; this interpretation is discussed with reference to a deficit at the level of the Supervisory Attentional System (Shallice, 1988).Peer reviewe

Exploring the Williams Syndrome face-processing debate: the importance of building developmental trajectories

Background: Face processing in Williams syndrome (WS) has been a topic of heated debate over the past decade. Initial claims about a normally developing (‘intact’) face-processing module were challenged by data suggesting that individuals with WS used a different balance of cognitive processes from controls, even when their behavioural scores fell within the normal range. Measurement of evoked brain potentials also point to atypical processes. However, two recent studies have claimed that people with WS process faces exactly like normal controls. Method: In this paper, we examine the details of this continuing debate on the basis of three new face-processing experiments. In particular, for two of our experiments we built task-specific full developmental trajectories from childhood to adolescence/ adulthood and plotted the WS data on these trajectories. Results: The first experiment used photos of real faces. While it revealed broadly equivalent accuracy across groups, the WS participants were worse at configural processing when faces were upright and less sensitive than controls to face inversion. In Experiment 2, measuring face processing in a storybook context, the face inversion effect emerged clearly in controls but only weakly in the WS developmental trajectory. Unlike the controls, the Benton Face Recognition Test and the Pattern Construction results were not correlated in WS, highlighting the different developmental patterns in the two groups. Again in contrast to the controls, Experiment 3 with schematic faces and non-face stimuli revealed a configural-processing deficit in WS both with respect to their chronological age (CA) and to their level of performance on the Benton. Conclusion: These findings point to both delay and deviance in WS face processing and illustrate how vital it is to build developmental trajectories for each specific task. Keywords: Williams syndrome, configural, holistic, featural, face processing, developmental trajectories, progressive modularisation of function

Sustainable food systems and nutrition in the 21st Century: a report from the 22nd Annual Harvard Nutrition Obesity Symposium

Food systems are at the center of a brewing storm consisting of a rapidly changing climate, rising hunger and malnutrition and significant social inequities. At the same time, there are vast opportunities to ensure that food systems produce healthy and safe food in equitable ways that promote environmental sustainability, especially if the world can come together at the UN Food Systems Summit in late 2021 and make strong and binding commitments towards food system transformation. The NIH-funded Nutrition Obesity Research Center at Harvard and the Harvard Medical School Division of Nutrition held their 22nd Annual Harvard Nutrition Obesity Symposium entitled ―Global Food Systems and Sustainable Nutrition in the 21st Century” in June 2021. This paper presents a synthesis of this symposium and highlights the importance of food systems to address the burden of malnutrition and non-communicable diseases, climate change, and the economic and social inequities. Transformation of food systems is possible, and the nutrition and health communities have a significant role to play in this transformative process