In-City Rain Mapping from Commercial Microwave Links-Challenges and Opportunities

Obtaining accurate rainfall measurements is highly important in urban areas, having a significant impact on different aspects in city life. Opportunistic rainfall sensing utilizing measurements collected by existing microwave and mmWave-based wireless networks has been researched in the last two decades and can be considered as an opportunistic integrated sensing and communication (ISAC) approach. In this paper, we compare two methods that utilize received signal level (RSL) measurements obtained by an existing smart-city wireless network deployed in the city of Rehovot, Israel, for rain estimation. The first method is a model-based approach using the RSL measurements from short links, in which two design parameters are calibrated empirically. This method is combined with a known wet/dry classification method, which is based on the rolling standard deviation of the RSL. The second method is a data-driven approach, based on a recurrent neural network (RNN), which is trained to estimate rainfall and classify wet/dry periods. We compare the results of rainfall classification and estimation from both methods and show that the data-driven approach slightly outperforms the empirical model and that the improvement is most significant for light rainfall events. Furthermore, we apply both methods to construct high-resolution 2D maps of accumulated rainfall in the city of Rehovot. The ground-level rainfall maps constructed over the city area are compared for the first time with weather radar rainfall maps obtained from the Israeli Meteorological Service (IMS). The rain maps generated by the smart-city network are found to be in agreement with the average rainfall depth obtained from the radar, demonstrating the potential of using existing smart-city networks as a source for constructing 2D high-resolution rainfall maps.

Optimal sequential detection of stimuli from multiunit recordings taken in densely populated brain regions

We address the problem of detecting the presence of a recurring stimulus by monitoring the voltage on a multiunit electrode located in a brain region densely populated by stimulus reactive neurons. Published experimental results suggest that under these conditions, when a stimulus is present, the measurements are gaussian with typical second-order statistics. In this letter we systematically derive a generic, optimal detector for the presence of a stimulus in these conditions and describe its implementation. The optimality of the proposed detector is in the sense that it maximizes the life span (or time to injury) of the subject. In addition, we construct a model for the acquired multiunit signal drawing on basic assumptions regarding the nature of a single neuron, which explains the second-order statistics of the raw electrode voltage measurements that are high-pass-filtered above 300 Hz. The operation of the optimal detector and that of a simpler suboptimal detection scheme is demonstrated by simulations and on real electrophysiological data.

Australian endodontists' perceptions of single and multiple visit root canal treatment

AIM

To ascertain endodontist's point of view (treatment philosophy, rationale and preference) regarding single- and multiple-visit root canal treatment. To identify the basis on which the choice is made and how the information necessary for the choice is acquired.

METHODOLOGY

Endodontists registered with the dental practice board of every state in Australia were contacted, and if they agreed to participate, they were interviewed either face to face or by telephone. The following topics were addressed in an interview lasting 15 to 20 min: demographics, current clinical procedures, treatment rationales and preference. A hypothetical scenario was posed to investigate which treatment regimen they would prefer to deliver if biological concerns were eliminated from consideration.

RESULTS

Fifty-two endodontists (71% of all Australian endodontists) agreed to participate in the study. Almost all (51/52) participants had performed single-visit root canal treatment, but very few routinely performed it. A majority of participants were willing to provide single-visit treatment where patients had time constraints, and in vital cases (including elective endodontics). The most powerful factor of influencing practice change was interpersonal contact with colleagues. Publications in academic journals have a weak influence in practice change.

CONCLUSIONS

Australian endodontists strongly prefer multiple-visit over single-visit root canal treatment even in cases where biological concerns are not an issue. Operator preference rather than biological or patient considerations appear to be the primary determinant of treatment choice.

The prevalence of postoperative pain and flare-up in single- and multiple-visit endodontic treatment: a systematic review

AIM

The aim of this systematic review was to assess the evidence regarding postoperative pain and flare-up of single- or multiple-visit root canal treatment.

METHODOLOGY

CENTRAL, MEDLINE and EMBASE databases were searched. Reference lists from identified articles were scanned. A forward search was undertaken on the authors of the identified articles. Papers that had cited these articles were also identified through Science Citation Index to identify potentially relevant subsequent primary research.

REVIEW METHODS

The included clinical studies compared the prevalence/severity of postoperative pain or flare-up in single- and multiple-visit root canal treatment. Data in those studies were extracted independently.

RESULTS

Sixteen studies fitted the inclusion criteria in the review, with sample size varying from 60 to 1012 cases. The prevalence of postoperative pain ranged from 3% to 58%. The heterogeneity amongst included studies was far too great to conduct meta-analysis and yield meaningful results.

CONCLUSION

Compelling evidence indicating a significantly different prevalence of postoperative pain/flare-up of either single- or multiple-visit root canal treatment is lacking.

Antibacterial efficacy of calcium hydroxide intracanal dressing: a systematic review and meta-analysis

AIM

To determine to what extent does calcium hydroxide intracanal medication eliminate bacteria from human root canals, compared with the same canals before medication, as measured by the number of positive cultures, in patients undergoing root canal treatment for apical periodontitis (teeth with an infected root canal system).

METHODOLOGY

CENTRAL, MEDLINE and EMBASE databases were searched. Reference lists from identified articles were scanned. A forward search was undertaken on the authors of the identified articles. Papers that had cited these articles were also identified through the Science Citation Index to identify potentially relevant subsequent primary research.

REVIEW METHODS

The included studies were pre-/post-test clinical trials comparing the number of positive bacterial cultures from treated canals. Data in those studies were independently extracted. Risk differences of included studies were combined using the generic inverse variance and random effect method.

RESULTS

Eight studies were identified and included in the review, covering 257 cases. Sample size varied from 18 to 60 cases; six studies demonstrated a statistically significant difference between pre- and post-medicated canals, whilst two did not. There was considerable heterogeneity among studies. Pooled risk difference was -21%; 95% CI: -47% to 6%. The difference between pre- and post-medication was not statistically significant (P = 0.12).

CONCLUSIONS

Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal when assessed by culture techniques.

Environmental monitoring by wireless communication networks

The global spread of wireless networks brings a great opportunity for their use in environmental studies. Weather, atmospheric conditions, and constituents cause propagation impairments on radio links. As such, while providing communication facilities, existing wireless communication systems can be used as a widely distributed, high-resolution atmospheric observation network, operating in real time with minimum supervision and without additional cost. Here we demonstrate how measurements of the received signal level, which are made in a cellular network, provide reliable measurements for surface rainfall. We compare the estimated rainfall intensity with radar and rain gauge measurements.

Conservative management of an intruded immature maxillary permanent central incisor with healing complication of pulp bone

Traumatic intrusion injury of permanent teeth is serious with multiple complications possible associated with the pulp, periodontal ligament, alveolar bone and Hertwig's epithelial root sheath. The optimal treatment for the management of an intrusion injury has not yet been determined. A case is presented involving the conservative management of an immature maxillary permanent central incisor intrusively luxated by allowing for re-eruption and orthodontic extrusion two weeks later. After a follow-up period of ten months, the intruded tooth continued to show a mobility of grade one, without metallic percussion tone or infra-occlusion, which confirmed periodontal ligament healing. Although the intruded tooth failed to respond to dry ice testing, no other signs of pulp necrosis were evident and the colour of the intruded tooth was within normal limits throughout the follow-up period. However, complications of healing of Hertwig's epithelial root sheath occurred, causing in-growth of bone and periodontal ligament into the root canal.

Underwater source detection using a spatial stationarity test

The problem of detecting a source in shallow water is addressed. The complexity of such a propagation channel makes precise modeling practically impossible. This lack of accuracy causes a deterioration in the performance of the optimal detector and motivates the search for suboptimal detectors which are insensitive to uncertainties in the propagation model. A novel, robust detector which measures the degree of spatial stationarity of a received field is presented. It exploits the fact that a signal propagating in a bounded channel induces spatial nonstationarity to a higher degree than mere background noise. The performance of the proposed detector is evaluated using both simulated data and experimental data collected in the Mediterranean Sea. This performance is compared to those of three other detectors, employing different extents of prior information. It is shown that when the propagation channel is not completely known, as is the case of the experimental data, the novel detector outperforms the others in terms of threshold signal-to-noise ratio (SNR). In the presence of environmental mismatch, the threshold SNR of the novel detector for the experimental data appears 2-5 dB lower than the other detectors. That is, this detector couples good performance with robustness to propagation uncertainties.

Long-term retention of a paper point in the periapical tissues: a case report

A case is reported of a 15 mm paper point found in the periapical area of a maxillary right central incisor during endodontic surgery for an unresolved periapical radiolucency. The paper point had been present for between five and nine years. Histopathological examination showed the presence of chronically inflamed fibrous connective tissue with a number of foreign body giant cells and focal collections of chronic inflammatory cells. SEM comparison of the specimen with a similarly treated fresh paper point showed no indication of degradation of the paper point by host defense cells.