Controlling inter-particle distances in crowds of motile, cognitive, active particles

Distance control in many-particle systems is a fundamental problem in nature. This becomes particularly relevant in systems of active agents, which can sense their environment and react by adjusting their direction of motion. We employ agent-based simulations to investigate the complex interplay between agent activity, characterized by Péclet number Pe , reorientation maneuverability Ω , vision angle θ and vision range R 0 , and agent density, which determines agent distancing and dynamics. We focus on semi-dense crowds, where the vision range is much larger than the particle size. The minimal distance to the nearest neighbors, exposure time, and persistence of orientation direction are analyzed to characterize the behavior. With increasing particle speed at fixed maneuverability, particles approach each other more closely, and exhibit shorter exposure times. The temporal persistence of motion decreases with increasing Pe , reflecting the impact of activity and maneuverability on direction changes. For a vision angle θ = π / 4 , we observe the emergence of flocking aggregates with a band-like structure, somewhat reminiscent of the bands in the Vicsek model. Additionally, for vision angles θ ≥ π / 2 , several quantities are found to display a universal scaling behavior with scaling variablePe 3 / 2 / Ω . Our results are in good agreement with recent experiments of pedestrians in confined spaces.

Emergent collective behavior of active Brownian particles with visual perception

Systems comprised of self-steering active Brownian particles are studied via simulations for a minimal cognitive flocking model. The dynamics of the active Brownian particles is extended by an orientational response with limited maneuverability to an instantaneous visual input of the positions of neighbors within a vision cone and a cut-off radius. The system exhibits large-scale self-organized structures, which depend on selected parameter values, and, in particular, the presence of excluded-volume interactions. The emergent structures in two dimensions, such as worms, worm-aggregate coexistence, and hexagonally close-packed structures, are analysed and phase diagrams are constructed. The analysis of the particle's mean-square displacement shows ABP-like dynamics for dilute systems and the worm phase. In the limit of densely packed structures, the active diffusion coefficient is significantly smaller and depends on the number of particles in the cluster. Our analysis of the cluster-growth dynamics shows distinct differences to processes in systems of short-range attractive colloids in equilibrium. Specifically, the characteristic time for the growth and decay of clusters of a particular size is longer than that of isotropically attractive colloids, which we attribute to the non-reciprocal nature of the directed visual perception. Our simulations reveal a strong interplay between ABP-characteristic interactions, such as volume exclusion and rotational diffusion, and cognitive-based interactions and navigation.

To study the awareness of osteoporosis in postmenopausal Indian women in a Northeast part of India: An evaluation of the Osteoporosis Health Belief Scale

Aim and Objective:

Our study's objective is to determine the level of awareness in postmenopausal women in Guwahati, Northeast part of India, using the Osteoporosis Health Belief Scale (OHBS).

Settings and Design:

Osteoporosis is the most common silent health problem in postmenopausal Indian women. An awareness level among this subset of women needs to study. The present study is based on a self-explanatory questionnaire.

Methods:

We conducted a self-explanatory questionnaire study on 2000 postmenopausal women in Guwahati, North East region of India. The bone mineral density (BMD) was measured using calcaneum Quantitative ultrasound (QUS) to assess BMD. Baseline characteristics were noted and analyzed.

Results:

The awareness level was noted only in757 (37.85%). Women with education level 12^th standard and above have some awareness regarding osteoporosis.

Conclusions:

Based on the present study, we can conclude that there is a lack of awareness in postmenopausal women regarding osteoporosis in India's North-East region. This subset of women is unaware of the condition that can leads to fragility fracture if not address in time. The study emphasizes that health care professionals should conduct frequent awareness programs in the community to prevent this silent disease, and morbidities so arise from osteoporosis can be minimized.

Assessment of climate change pattern in the Pauri Garhwal of the Western Himalayan Region: based on climate parameters and perceptions of forest-dependent communities

This study assessed the climate change in Pauri district, Uttarakhand, India, a region highly vulnerable to climate change with potentially high loss of livelihoods and lives. The scale of change in the district's climate was analyzed using meteorological station data (1901-2000) and grid data (1985-2015). Perceptions of climate change among forest-dependent communities in three altitude zones (< 1200 m asl (zone A); 1200-1800 m asl (zone B), and > 1800 m asl (zone C)) in the study region were surveyed with respect to 14 climate-specific indicators. Annual mean, maximum, and minimum temperature of seasonal data indicated increasing trends except monsoon. Percentage cloud cover showed an increase, of approximately 3%, while diurnal temperature displayed decreasing trends. Rainfall in the district showed a decreasing trend, with more than 50% of years 1985-2015 receiving less rainfall than the annual average. More than 90% of respondents in zones A and B, and around 65-70% respondents in zone C, reported changes in climate parameters. These findings confirm the long-term observable changes in climate in the region and demonstrate the utility of station data, grid data, and surveys of local communities' perceptions when analyzing climate change. The analysis provided important clues about the nature of climate changes in the district. The results can be used to reduce the gap between bottom-up understanding and top-down policies and to formulate precautionary and ongoing site-specific adaptation practices for communities in different altitude zones in the study region, leading to effective and efficient mitigation of climate change impacts.

MR Geyser Sign in chronic rotator cuff tears

Acromio-clavicular (AC) joint cysts are rare presentation of chronic shoulder pathology. These cysts may be observed secondary to either degenerative changes in the AC joint with an intact rotator cuff (type 1 cyst) or following a chronic rotator cuff tear (type 2 cyst). The latter phenomenon is known as Geyser Sign and is described by ultrasound, conventional arthrogram and magnetic resonance imaging (MRI). We present a case of chronic rotator cuff tear presenting with a large type 2 cyst and Geyser Sign on MRI.

Spectrum of Clinical Presentation of Pulmonary Alveolar Microlithiasis: Case Series from North India

We describe five cases of pulmonary alveolar microlithiasis (PAM) from North India with characteristic radiological and histopathological features. All patients were symptomatic with variable severity and duration of the symptoms and one patient developed cor-pulmonale during the course of follow-up. Diagnosis of PAM was suspected on the basis of classical sand-storm appearance on radiological examination and confirmed by transbronchial lung biopsy in four of the five cases. Apart from other features, presence of pleural and pericardial calcification in one case makes this discussion valuable. Awareness of this specific entity among the clinicians is essential to avoid unnecessary investigations.

Askin's tumour in pregnancy with dismal prognosis

Askin's tumour is a rare malignant neoplasm of the chest wall. A 23-year-old primigravida patient was admitted to the hospital with complaints of chest wall swelling, cough and dyspnoea. Radiological examination showed a chest wall mass in right hemithorax with erosion of ribs and moderate pleural effusion. Fine-needle aspiration cytology was suggestive of malignant small round cell tumour. Immunohistochemical analysis together with the clinical and radiological findings led to the definitive diagnosis of Askin's tumour. Despite receiving multimodality therapy, she had residual soft tissue mass and died after 6 months. Rarity of this malignancy during pregnancy renders the case unique.

Hydatid disease of the lung mimicking a pericardial cyst

We report a young girl who presented to us with chest discomfort and had a paracardiac mass on chest radiograph. Computerised tomographic (CT) scan of the thorax was suggestive of pericardial cyst. Hydatid serology was negative. The cyst was excised.