A Single Deformed Bow Shock for Titan-Saturn System

During periods of high solar wind pressure, Saturn's bow shock is pushed inside Titan's orbit exposing the moon and its ionosphere to the solar wind. The Cassini spacecraft's T96 encounter with Titan occurred during such a period and showed evidence for shocks associated with Saturn and Titan. It also revealed the presence of two foreshocks: one prior to the closest approach (foreshock 1) and one after (foreshock 2). Using electromagnetic hybrid (kinetic ions and fluid electrons) simulations and Cassini observations, we show that the origin of foreshock 1 is tied to the formation of a single deformed bow shock for the Titan‐Saturn system. We also report the observations of a structure in foreshock 1 with properties consistent with those of spontaneous hot flow anomalies formed in the simulations and previously observed at Earth, Venus, and Mars. The results of hybrid simulations also show the generation of oblique fast magnetosonic waves upstream of the outbound Titan bow shock in agreement with the observations of large‐amplitude magnetosonic pulsations in foreshock 2. We also discuss the implications of a single deformed bow shock for new particle acceleration mechanisms and also Saturn's magnetopause and magnetosphere

Transient Foreshock Structures Upstream of Mars: Implications of the Small Martian Bow Shock

We characterize the nature of magnetic structures in the foreshock region of Mars associated with discontinuities in the solar wind. The structures form at the upstream edge of moving foreshocks caused by slow rotations in the interplanetary magnetic field (IMF). The solar wind plasma density and the IMF strength noticeably decrease inside the structures' core, and a compressional shock layer is present at their sunward side, making them consistent with foreshock bubbles (FBs). Ion populations responsible for these structures include backstreaming ions that only appear within the moving foreshock, and accelerated reflected ions from the quasi-perpendicular bow shock. Both ion populations accumulate near the upstream edge of the moving foreshock which facilitates FB formation. Reflected ions with hybrid trajectories that straddle between the quasi-perpendicular and quasi-parallel bow shocks during slow IMF rotations contribute to formation of foreshock transients.Comment: Submitted to Geophysical Research Letter

Characterizing cometary electrons with kappa distributions

The Rosetta spacecraft has escorted comet 67P/Churyumov-Gerasimenko since 6 August 2014 and has offered an unprecedented opportunity to study plasma physics in the coma. We have used this opportunity to make the fi rst characterization of cometary electrons with kappa distributions. Two three-dimensional kappa functions were fi t to the observations, which we interpret as two populations of dense and warm (density=10cm 3 , temperature=2×10 5 K, invariant kappa index=10 > 1000), and rare fi ed and hot (density=0.005cm 3 , temperature=5×10 5 K, invariant kappa index=1 – 10) electrons. We fi t the observations on 30 October 2014 when Rosetta was 20km from 67P, and 3AU from the Sun. We repeated the analysis on 15 August 2015 when Rosetta was 300km from the comet and 1.3AU from the Sun. Comparing the measurements on both days gives the fi rst comparison of the cometary electron environment between a nearly inactive comet far from the Sun and an active comet near perihelion. We fi nd that the warm population density increased by a factor of 3, while the temperature cooled by a factor of 2, and the invariant kappa index was unaffected. We fi nd that the hot population density increased by a factor of 10, while the temperature and invariant kappa index were unchanged. We conclude that the hot population is likely the solar wind halo electrons in the coma. The warm population is likely of cometary origin, but its mechanism for production is not known

A cluster-driven energy routing protocol for optimal network lifetime in ad hoc networks

Mobile Ad hoc Network (MANET) is a group of networked mobile devices working in a cooperative manner. Due to usage, these devices quickly run out of battery power in critical situations and consequently fail in packet transmission. Power-Efficient Gathering in Sensor Information Systems (PEGASIS) and Dynamic State algorithm are two research works with unique energy efficiency concepts that, if harmonized and refined, will deliver a better optimized energy-efficient routing protocol for MANETs. This study, therefore, proposes PEGADyn – a hybrid version of PEGASIS and Dynamic State algorithm for a new energy-efficient routing protocol in ad hoc networks. PEGADyn creates a virtual grid classification of nodes based on current location, followed by a cluster formation of nodes in each virtual grid created. In each cluster and virtual grid formed, cluster heads (CHs) and designated cluster heads (dCH) are selected based on their energy levels. CHs and dCHs are used for communication between clusters and virtual grids. The use of CHs and dCHs limits communication overheads among nodes, reducing the energy expended and increasing the network lifetime. A simulation comparison of PEGADyn with PEGASIS and Dynamic State shows PEGADyn to be better in extending network lifetime and maintaining network throughput

Designing a memory-aid and reminder system for dementia patients and older adults

The United Nations statistics show that our society is rapidly aging, and this has led to the surge in the development of assisted living technologies. Of note is the minimal attention given to the assisted living technologies for dementia sufferers. This research study therefore, proposes the design of an assisted living technology that could aid older adults and dementia sufferers to lead an independent life. The design incorporates speech system, schedules and task reminders, video and picture reminders of loved ones, events etc. Although there are some available systems that aid these sufferers, however, most of these systems are geared towards monitoring of patients due to accidents or sudden changes in their health conditions rather than assisting them to live an independent life. The novelty of our system provides the ability for sufferers and older adults to live an independent life while also providing a monitoring system for healthcare workers and loved ones of the patients

mHealth and big-data integration: promises for healthcare system in India

BACKGROUND The use of mobile devices in health (mobile health/mHealth) coupled with related technologies promises to transform global health delivery by creating new delivery models that can be integrated with existing health services. These delivery models could facilitate healthcare delivery into rural areas where there is limited access to high-quality access care. Mobile technologies, Internet of Things and 5G connectivity may hold the key to supporting increased velocity, variety and volume of healthcare data. OBJECTIVE The purpose of this study is to identify and analyse challenges related to the current status of India’s healthcare system—with a specific focus on mHealth and big-data analytics technologies. To address these challenges, a framework is proposed for integrating the generated mHealth big-data and applying the results in India's healthcare. METHOD A critical review was conducted using electronic sources between December 2018 and February 2019, limited to English language articles and reports published from 2010 onwards MAIN OUTCOME This paper describes trending relationships in mHealth with big-data as well as the accessibility of national opportunities when specific barriers and constraints are overcome. The paper concentrates on the healthcare delivery problems faced by rural and low-income communities in India to illustrate more general aspects and identify key issues. A model is proposed that utilises generated data from mHealth devices for big-data analysis that could result in providing insights into the India population health status. The insights could be important for public health planning by the government towards reaching the Universal Health Coverage. CONCLUSION Biomedical, behavioural and lifestyle data from individuals may enable customised and improved healthcare services to be delivered. The analysis of data from mHealth devices can reveal new knowledge to effectively and efficiently support national healthcare demands in less developed nations, without fully accessible healthcare systems

Ionospheric density depletions around crustal fields at Mars and their connection to ion frictional heating

Mars' ionosphere is formed through ionization of the neutral atmosphere by solar irradiance, charge exchange, and electron impact. Observations by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft have shown a highly dynamic ionospheric layer at Mars impacted by loss processes including ion escape, transport, and electron recombination. The crustal fields at Mars can also significantly modulate the ionosphere. We use MAVEN data to perform a statistical analysis of density depletions of ionospheric species (O+, O2+, and electrons) around crustal fields. Events mostly occur when the crustal magnetic fields are radial, outward, and with a mild preference towards east in the planetocentric coordinates. We show that events near crustal fields are typically accompanied by an increase in suprathermal electrons within the depletion, either throughout the event or as a short-lived electron beam. However, no correlation between the changes in the bulk electron densities and suprathermal electron density variations is observed. Our analysis indicates that the temperature of the major ionospheric species, O2+, increases during most of the density depletion events, which could indicate that some ionospheric density depletions around crustal fields are a result of ion frictional heating.</p