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Autonomous teams of unmanned ground and air vehicles rely on networking and distributed processing to collaborate as they jointly localize, explore, map, and learn in sometimes difficult and adverse conditions. Co-designed intelligent wireless networks are needed for these autonomous mobile agents for applications including disaster response, logistics and transportation, supplementing cellular networks, and agricultural and environmental monitoring. In this paper we describe recent progress on wireless networking and distributed processing for autonomous systems using a low frequency portion of the electromagnetic spectrum, here defined as roughly 25 to 100 MHz with corresponding wavelengths of 3 to 12 meters. This research is motivated by the desire to support autonomous systems operating in dense and cluttered environments by harnessing low frequency propagation, where meters long wavelengths yield significantly reduced scattering and enhanced penetration of obstacles and structures. This differs considerably from higher frequency propagation, requiring different low frequency propagation models than those widely employed for other bands. Progress in use of low frequency for autonomous systems has resulted from combined advances in low frequency propagation modeling, networking, antennas and electromagnetics, geolocation, multi-antenna array distributed beamforming, and mobile collaborative processing. This article describes the breadth and the depth of interaction between areas, leading to new tools and methods, especially in physically complex indoor/outdoor, dense urban, and other challenging scenarios. We bring together key results, models, measurements, and experiments that describe the state of the art for new uses of low frequency spectrum for multi-agent autonomy.

IntroductionMany studies have documented the profound impact that the mother-child relationship has on child sociality and behavior. However, the biological mechanisms that govern the relationship are poorly understood. We developed a mother-child emotional preparation program (MCEP), based on a novel autonomic nervous system learning mechanism. MCEP is hypothesized to condition the child's autonomic nervous system to better meet the preschool socioemotional classroom challenges.MethodsWe conducted a randomized controlled trial of MCEP, comparing a group of children receiving standard curriculum with children receiving standard curriculum plus MCEP. Previously, we reported that the MCEP mother-child dyads (vs controls) were more emotionally connected at six months post intervention and MCEP children (vs controls) displayed better socioemotional behavior at home and in the classroom. At six months post intervention, mothers and children underwent a stressful interaction-interruption paradigm, during which we acquired child ECG. We analyzed heart rate and several measures of child heart rate variability obtained during the 10-minute post-stress recovery period.ResultsWe found that MCEP children showed better autonomic regulation following the stressor, as measured by lower heart rate (p = 0.017) and increased high frequency respiratory sinus arrhythmia (RSA) or vagal tone (p = 0.043). Surprisingly, despite a sample size limited by COVID (n = 12 and 12), the effect sizes were large (g's ranging from 0.89 to 1.09). In addition, we found significant correlations with large effect sizes between autonomic measures and scores on the Welch Emotional Connection Screen (WECS).DiscussionThese findings support the conclusion that MCEP had a significant positive impact on child autonomic regulation in response to stress, which correlates with behavioral assessments of emotional connection. We discuss theoretical considerations and the implications of our findings for preschool education programs in general. This trial was retrospectively registered (clinicaltrial.gov registry NCT02970565) three months after the start of the first recruitment on April 9, 2019.

Understanding circuit-level manipulations that affect the brain’s capacity for plasticity will inform the design of targeted interventions that enhance recovery after stroke. Following stroke, increased contralesional activity (e.g. use of the unaffected limb) can negatively influence recovery, but it is unknown which specific neural connections exert this influence, and to what extent increased contralesional activity affects systems- and molecular-level biomarkers of recovery. Here, we combine optogenetic photostimulation with optical intrinsic signal imaging to examine how contralesional excitatory activity affects cortical remodeling after stroke in mice. Following photothrombosis of left primary somatosensory forepaw (S1FP) cortex, mice either recovered spontaneously or received chronic optogenetic excitation of right S1FP over the course of 4 weeks. Contralesional excitation suppressed perilesional S1FP remapping and was associated with abnormal patterns of stimulus-evoked activity in the unaffected limb. This maneuver also prevented the restoration of resting-state functional connectivity (RSFC) within the S1FP network, RSFC in several networks functionally distinct from somatomotor regions, and resulted in persistent limb-use asymmetry. In stimulated mice, perilesional tissue exhibited transcriptional changes in several genes relevant for recovery. Our results suggest that contralesional excitation impedes local and global circuit reconnection through suppression of cortical activity and several neuroplasticity-related genes after stroke, and highlight the importance of site selection for targeted therapeutic interventions after focal ischemia.

In this paper, we study a wireless network where multiple distributed transmitters control the phases of their signals so that they can be constructively combined at a client receiver. Unlike centralized beamforming with co-located and phase-synchronized antennas, geographically separated transmitters experience phase offsets caused by the individual local oscillators. In practical scenarios, the transmitters should not be placed too close to each other in order to alleviate mutual coupling effects and extend the coverage region. In this regard, we model the spatial distribution of the transmitters as a β -Ginibre point process that models the repulsive feature. We investigate two types of transmission strategies: (i) Transmitter selection in which the client selects the transmitter providing the highest received power at the client, and (ii) Coherent beamforming in which multiple transmitters send their signals simultaneously to the client in the presence of phase offsets among the transmitters. We introduce the exact expression of the coverage probability of the transmitter selection method. Also, we derive an approximation of the coverage probability of the coherent beamforming scheme by leveraging two scaling factors that respectively capture the impacts of the phase offsets and the degree of repulsion on the coverage probability. From numerical simulations, we validate the accuracy of our analysis.

Chronic rhinosinusitis (CRS) is an inflammatory condition that affects up to 12% of the human population in developed countries. Previous studies examining the potential role of the sinus bacterial microbiota within CRS infections have found inconsistent results, possibly because of inconsistencies in sampling strategies. The aim of this study was to determine whether the sinus microbiome is altered in CRS and additionally if the middle meatus is a suitable representative site for sampling the sinus microbiome. Swab samples were collected from 12 healthy controls and 21 CRS patients, including all eight sinuses for CRS patients and between one and five sinuses for control subjects. The left and right middle meatus and nostril swabs were also collected. Significant differences in the sinus microbiomes between CRS and control samples were revealed using high-throughput 16S rRNA gene sequencing. The genus Escherichia was over-represented in CRS sinuses, and associations between control patients and Corynebacterium and Dolosigranulum were also identified. Comparisons of the middle meatuses between groups did not reflect these differences, and the abundance of the genus Escherichia was significantly lower at this location. Additionally, intra-patient variation was lower between sinuses than between sinus and middle meatus, which together with the above results suggests that the middle meatus is not an effective representative sampling site.

A unilateral tumour in the nasal cavity or paranasal sinuses is commonly caused by polyps, cysts, and mucoceles, as well as invasive tumours such as papillomas and squamous cell carcinomas. Schwannomas, in contrast, are rare lesions in this area (Minhas et al., 2013). We present a case of a 52-year-old female who presented with a 4-year progressive history of mucous hypersecretion, nasal obstruction, pain, and fullness. Imaging of the paranasal sinuses showed complete opacification of the entire left nasal cavity and sinuses by a tumour causing subsequent obstruction of the frontal and maxillary sinuses. The tumour was completely excised endoscopically. Histopathology was consistent with that of a schwannoma.