Nature in motion: The tuning of the visual system to the spatiotemporal properties of natural scenes.

Natural scenes contain several statistical regularities despite their superficially diverse appearances (e.g., mountains, rainforests, deserts). First, they exhibit a unique distribution of luminance intensities decreasing across spatial frequency, known as the 1/fα amplitude spectrum (α ≈ 1). Additionally, natural scenes share consistent geometric properties, comprising similar densities of structure across multiple scales-a property classifying them as fractal (e.g., how the branching patterns of rivers and trees appear similar irrespective of scale). These two properties are intimately related and correlate strongly in natural scenes. However, research using thresholded noise images suggests that spatially, the human visual system is preferentially tuned to natural scene structure more so than 1/fα spectra. It is currently unclear whether this dependency on natural geometry extends to the temporal domain. We used a psychophysics task to measure discrimination sensitivity toward two types of synthetic noise movies: gray scale and thresholded (N = 60). Each movie type shared the same geometric properties (measured fractal D), but substantially differing spectral properties (measured α). In both space and time, we observe a characteristic dependency on stimulus structure across movie types, with sensitivity peaking for stimuli with natural geometry despite having altered 1/fα spectra. Although only measured behaviorally, our findings may imply that the neural processes underlying this tuning have developed to be sensitive to the most stable signal in our natural environment-structure (e.g., the structural properties of a tree are consistent from morning to night despite illumination changes across time points).

Nursing students' attitudes towards mental illness: A multi-national comparison.

Accessible Summary What is known on the subject Health professionals, including nurses, are shown to have stigmatizing attitudes towards mental illness. For nursing students who are in their formative years of professional development, mental illness stigma can severely impact the care they provide. Little research has investigated multi-national comparisons of nursing students' attitudes towards mental illness. What this paper adds to existing knowledge This study shows that between countries, there were substantial differences amongst nursing students in stigmatizing attitudes towards mental illness. Cultural perspectives may explain some of these differences. What are the implications for practice Regardless of location, stigmatizing attitudes are present at varying levels. Each nation can take steps to reduce these by acknowledging the presence of stigmatizing attitudes amongst nurses, educating nurses regarding the negative impacts of stigma on patient outcomes, and decrease stigmatizing attitudes by facilitating opportunities for nurses (particularly student nurses) to have direct contact with people with lived experiences of mental illness. ABSTRACT: INTRODUCTION: Stigmatizing attitudes perpetuated by nursing professionals are a pervasive problem for people experiencing mental health issues. This global issue has detrimental consequences; inhibiting one's life chances and help-seeking behaviours. To date, few studies have compared nursing students' attitudes towards mental illness from a multi-national perspective. AIM: To compare undergraduate nursing students' attitudes towards mental illness across six countries: Australia, India, Jordan, Saudi Arabia, Taiwan and USA. METHOD: In a cross-sectional design, data were collected from undergraduate nursing students (N = 426) using the Social Distance Scale. A one-way analysis of variance was used to compare differences between countries. RESULTS: Nursing students' attitudes to mental illness differed between countries. Social Distance Scores were highest amongst nursing students from Jordan and Saudi Arabia. Students from Taiwan and India possessed moderate stigma scores. Social Distance Scores from the USA and Australia were lowest. DISCUSSION: Clear differences in stigmatizing attitudes emerged between countries; these are discussed in relation to possible cultural influences. IMPLICATIONS FOR PRACTICE: It is suggested that educating nurses, combined with direct contact with people with lived experiences of mental illness, can reduce stigmatizing attitudes regardless of country, location or educational institution.

HumanBrainAtlas: an in vivo MRI dataset for detailed segmentations.

We introduce HumanBrainAtlas, an initiative to construct a highly detailed, open-access atlas of the living human brain that combines high-resolution in vivo MR imaging and detailed segmentations previously possible only in histological preparations. Here, we present and evaluate the first step of this initiative: a comprehensive dataset of two healthy male volunteers reconstructed to a 0.25 mm isotropic resolution for T1w, T2w, and DWI contrasts. Multiple high-resolution acquisitions were collected for each contrast and each participant, followed by averaging using symmetric group-wise normalisation (Advanced Normalisation Tools). The resulting image quality permits structural parcellations rivalling histology-based atlases, while maintaining the advantages of in vivo MRI. For example, components of the thalamus, hypothalamus, and hippocampus are often impossible to identify using standard MRI protocols-can be identified within the present data. Our data are virtually distortion free, fully 3D, and compatible with the existing in vivo Neuroimaging analysis tools. The dataset is suitable for teaching and is publicly available via our website (hba.neura.edu.au), which also provides data processing scripts. Instead of focusing on coordinates in an averaged brain space, our approach focuses on providing an example segmentation at great detail in the high-quality individual brain. This serves as an illustration on what features contrasts and relations can be used to interpret MRI datasets, in research, clinical, and education settings.

Nice and slow: Measuring sensitivity and visual preference toward naturalistic stimuli varying in their amplitude spectra in space and time.

The 1/fα amplitude spectrum is a statistical property of natural scenes characterising a specific distribution of spatial and temporal frequencies and their associated luminance intensities. This property has been studied extensively in the spatial domain whereby sensitivity and visual preference overlap and peak for slopes within the natural range (α ≈ 1), but remains relatively less studied in the temporal domain. Here, we used a 4AFC task to measure sensitivity and a 2AFC task to measure visual preference and across a wide range of spatial (α = 0.25, 1.25, 2.25) and temporal (α = 0.25 to 2.50, step size: 0.25) slope conditions. Stimuli with a shallow temporal slope modulate rapidly (e.g. 0.25), whereas stimuli with a steep slope modulate slowly (e.g. 2.25). Interestingly, sensitivity and visual preference did not closely overlap. While the sensitivity of the visual system is highest for our stimulus with an intermediate modulation rate (1.25), which is most abundant in nature, the stimulus with the slowest modulation rate (2.25) was most preferred. It seems sensible for the visual system to be sensitive to spatiotemporal spectra that most commonly exist in nature (α ≈ 1). However, it is possible that preference might be related to what these properties signal in the natural world. Consider the cases of waves slowly vs. rapidly crashing on a beach or fast vs. slow animals. In both instances the slowest option is often the safest and preferential, suggesting that the temporal 1/fα amplitude spectrum provides additional information that may indicate preferred environmental conditions.

Walking speed and global cognition: results from the OKLAHOMA Study.

Executive functioning and processing speed have been related to physical functioning in non-demented, elderly samples; however, the relationship between walking speed and global cognition has not been examined. Six hundred and seventy-five community dwelling older adults were enrolled through their primary care physicians. Walking speed was assessed on a 50-foot course at usual pace. Global cognition was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Total Scale score. After adjusting for age, gender, and education, there was a strong inverse relationship between walking speed and global cognition, with slower walkers performing worse on the cognitive measures, faster walkers performing better on the cognitive measures, and the intermediate walkers performing in the middle. In these older adults, global cognition was related to walking speed.

Medical burden and cognition in older patients in primary care: selective deficits in attention.

Cognitive deficits have been associated with several chronic medical conditions, but the additive effects of multiple conditions on cognition have less studied. Six hundred ninety-two community dwelling older adults were enrolled through their primary care physicians and evaluated for medical burden and cognition. Medical burden was assessed by self-report questionnaire. Cognition was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). After adjusting for age and gender, there was a strong inverse relationship between medical burden and cognition, with individuals with more medical comorbidities performing worse on cognitive measures. Attention was selectively poor, especially for a speeded, divided attention task, in patients with five or more comorbid medical conditions. These findings could have clinical implications, as poorer attention, especially in patients with multiple medical problems, could lead to poorer medical compliance and worse outcomes.

Elevated serum parathormone level after "concise parathyroidectomy" for primary sporadic hyperparathyroidism.

BACKGROUND: Cure after parathyroid exploration is traditionally assessed by serum calcium concentration 6 months postoperatively. Postoperative normocalcemic elevation of serum parathormone (PTH) level has been described but is of unclear significance. METHODS: In a 6-year prospective study of outcomes in 380 patients undergoing initial parathyroidectomy for primary sporadic hyperparathyroidism, we measured intact serum PTH and calcium levels at more than 5 months. Those with normocalcemic high PTH levels were begun on oral calcium + vitamin supplements and monitored. RESULTS: At more than 5 months postoperatively, normocalcemic elevation in serum PTH level occurred in 28% of patients, was more common after resection of double adenomas (P =.01), and predated the onset of recurrent hypercalcemia in 3 of 3 patients with unrecognized multiglandular disease. Although delayed treatment with calcium and vitamin supplements produced no clear benefit, patients who took such supplements from the date of surgery were much less likely to have an elevated serum PTH level more than 5 months later (P =.0005). CONCLUSIONS: After successful parathyroid surgery, compensatory normocalcemic elevation in serum PTH level is frequent and may arise from dietary deficiency. Monitored supplemental intake of calcium and vitamin D appears to prevent or to normalize the condition in most patients. Patients with normocalcemic elevation in serum PTH level should receive evaluation for dietary deficiencies as well as follow-up for possible residual disease.

Teflon-induced granuloma: a false-positive finding with PET resolved with combined PET and CT.

Patients who have undergone thyroidectomy may have recurrent laryngeal nerve injury; until recently, Teflon injection was commonly used for vocal cord medialization. We present a case of a patient who underwent thyroidectomy who had significantly increased and unilateral (18)F-fluorodeoxyglucose uptake in the neck, which was found to be localized to the left vocal cord by use of combined positron emission tomography (PET) and CT, presumably because of a Teflon-induced granuloma. Knowledge of this potential source of false-positive PET interpretation because of its inability to precisely localize neoplastic lesions, and the use of combined PET and CT imaging, may allow precise diagnosis and prevention of unnecessary interventions.

Elastically relaxed free-standing strained-silicon nanomembranes.

Strain plays a critical role in the properties of materials. In silicon and silicon-germanium, strain provides a mechanism for control of both carrier mobility and band offsets. In materials integration, strain is typically tuned through the use of dislocations and elemental composition. We demonstrate a versatile method to control strain by fabricating membranes in which the final strain state is controlled by elastic strain sharing, that is, without the formation of defects. We grow Si/SiGe layers on a substrate from which they can be released, forming nanomembranes. X-ray-diffraction measurements confirm a final strain predicted by elasticity theory. The effectiveness of elastic strain to alter electronic properties is demonstrated by low-temperature longitudinal Hall-effect measurements on a strained-silicon quantum well before and after release. Elastic strain sharing and film transfer offer an intriguing path towards complex, multiple-layer structures in which each layer's properties are controlled elastically, without the introduction of undesirable defects.