Search Results (11)

A Cl-rich annitic mica is present in zones in taxitic gabbro–dolerite enriched in base metal sulfides in the eastern portion of the Oktyabrsky deposit in the Norilsk complex (Russia). Other Cl-enriched minerals in the assemblage include hastingsite (4.06 wt.% Cl), ferro-hornblende (2.53 wt.%), and chlorapatite (>6 wt.%). New wavelength-dispersive electron probe analyses reveal compositions with up to 7.75 wt.% Cl, corresponding to the formula K_0.742Na_0.047Ca_0.007)_Σ0.796 (Fe²⁺_2.901Mg_0.078Mn_0.047Ti_0.007Cr_0.003)_Σ3.036 (Si_3.190Al_0.782)_Σ3.972O₁₀ (Cl_1.105OH_0.854F_0.041)_Σ2.000 based on 22 negative charges per formula unit, in which OH(calc.) = 2 − (Cl + F). Unfortunately, the grain size of the Cl-dominant mica precluded a single-crystal X-ray diffraction study even though its EBSD pattern confirms its identity as a member of the Mica group. We present results of a refinement of a crystal from the same mineralized sample containing 0.90(6) apfu Cl [R1 = 7.89% for 3720 unique reflections]. The mica is monoclinic, space group C2/m, a 5.3991(4), b 9.3586(6), c 10.2421(10) Å, β 100.873(9)°, V = 508.22(7) ų, Z = 2. We also describe physical properties and provide a Raman spectrum. Among the mica compositions acquired from the same sample, a high Cl content is correlated with relative enrichment in Si, Mn, and Na and with a depletion in Al, Mg (low Mg#), K, Cr, and Ti. The buildup in Cl in the ore-forming environment is ultimately due to efficient fractional crystallization of the basic magma, with possible contributions from the Devonian metasedimentary sequences that it intruded. Full article

Background: Stigma education for nursing students has focused solely on stigma reduction, with studies showing temporary improvements in attitudes. However, nursing education research should also emphasize the importance of critical reflection and self-reflection to enhance attitudes, beliefs, topic comprehension, and learning satisfaction. This study aimed to evaluate the effectiveness of the “This is me” intervention regarding knowledge, attitudes, and communication skills of senior undergraduate nursing students in responding to mental illness-related stigma. Methods: This study employed a psychoeducational intervention for reducing mental illness stigma, using a questionnaire survey to assess pre- and post-intervention effects, with 37 eligible nursing students undergoing clinical training in psychiatric services between 16 May and 15 July 2022. Instruments included sociodemographic and health questions, the MICA-4 scale to evaluate students’ attitudes toward mental illness, the MAKS to measure mental health knowledge, the Empathy Scale (JSPE-S), the Intergroup Anxiety Scale (SS-12), and the Attribution Questionnaire (AQ-27). Results: Most students were female (73.0%) and single (70.3%), with a mean age of around 29 years. After implementing the psychoeducational program, there was a statistically significant increase in overall stigma-related knowledge (MAKS: Z = −1.99, p < 0.05), a decrease in intergroup anxiety (IAS: Z = −3.42, p < 0.05), and reductions in the perceptions of patients as dangerous (AQ27—Dangerousness: Z = −2.399, p < 0.05) and fear (AQ27—Fear: Z = −2.415, p < 0.05). Additionally, there was an improvement in empathy, specifically in Perspective Taking (JSPE: Z = −2.555, p < 0.05). Conclusions: This program may contribute to mental health literacy related to stigma, positively impacting therapeutic relationships and communication with people with mental illness and resulting in more effective care practices. Full article

Digital transformation has increased its proportion in the last few years and the Internet-on-Things (IoT) domain is not an exception, with more and more devices or sensors being connected to the Internet and transmitting different types of data. Usually, being part of more complex IT systems, it must be ensured that the IoT devices transmitting the data are authenticated components of the system before sending the data to a storage server. However, usually, IoT devices have limited computing power, therefore all of the work that they are doing should not be too expensive in terms of computations. This is the case for the authentication mechanism, too. Having this context, in this paper, we propose an authentication mechanism for IoT devices based on elliptic curves, which are known as having a low computational cost compared to other techniques used in cryptography that provide the same level of security. The proposed system includes a blockchain network that will verify the identity of the device which tries to connect within the system to send the data to the storage server, a process that will be made together with the storage server. Once the identity is valid, the blockchain records the transaction and the storage server initiates the data transmission process. Besides including a lightweight authentication mechanism, the proposed method has several other important properties due to it using the blockchain network. Compared to the related work that we analyzed, we show that the proposed authentication mechanism is secure against common attacks designed for IoT devices. The performance analysis shows that the authentication query made by the IoT device takes place in less than a second on both a MSP430F1611 microcontroller and a MICAz sensor. Full article

${\alpha }_1$-Antitrypsin is a protease inhibitor belonging to the serpin family. Serpin polymerisation is at the core of a class of genetic conformational diseases called serpinopathies. These polymers are known to be unbranched, flexible, and heterogeneous in size with a beads-on-a-string appearance viewed by negative stain electron microscopy. Here, we use atomic force microscopy and time-lapse dynamic light scattering to measure polymer size and shape for wild-type (M) and Glu342→Lys (Z) ${\alpha }_1$-antitrypsin, the most common variant that leads to severe pathological deficiency. Our data for small polymers deposited onto mica and in solution reveal a power law relation between the polymer size, namely the end-to-end distance or the hydrodynamic radius, and the polymer mass, proportional to the contour length. We use the scaling concepts of polymer physics to assess that ${\alpha }_1$-antitrypsin polymers are random linear chains with a low persistence length. Full article

This study presents the latest updates to the Audubon Society of Western Pennsylvania (ASWP) testbed, a $50,000 USD, 104-node outdoor multi-hop wireless sensor network (WSN). The network collects environmental data from over 240 sensors, including the EC-5, MPS-1 and MPS-2 soil moisture and soil water potential sensors and self-made sap flow sensors, across a heterogeneous deployment comprised of MICAz, IRIS and TelosB wireless motes. A low-cost sensor board and software driver was developed for communicating with the analog and digital sensors. Innovative techniques (e.g., balanced energy efficient routing and heterogeneous over-the-air mote reprogramming) maintained high success rates (>96%) and enabled effective software updating, throughout the large-scale heterogeneous WSN. The edaphic properties monitored by the network showed strong agreement with data logger measurements and were fitted to pedotransfer functions for estimating local soil hydraulic properties. Furthermore, sap flow measurements, scaled to tree stand transpiration, were found to be at or below potential evapotranspiration estimates. While outdoor WSNs still present numerous challenges, the ASWP testbed proves to be an effective and (relatively) low-cost environmental monitoring solution and represents a step towards developing a platform for monitoring and quantifying statistically relevant environmental parameters from large-scale network deployments. Full article

The Smart Grid (SG) is conceived as the evolution of the current electrical grid representing a big leap in terms of efficiency, reliability and flexibility compared to today’s electrical network. To achieve this goal, the Wireless Sensor Networks (WSNs) are considered by the scientific/engineering community to be one of the most suitable technologies to apply SG technology to due to their low-cost, collaborative and long-standing nature. However, the SG has posed significant challenges to utility operators—mainly very harsh radio propagation conditions and the lack of appropriate systems to empower WSN devices—making most of the commercial widespread solutions inadequate. In this context, and as a main contribution, we have designed a comprehensive ad-hoc WSN-based solution for the Smart Grid (SENSED-SG) that focuses on specific implementations of the MAC, the network and the application layers to attain maximum performance and to successfully deal with any arising hurdles. Our approach has been exhaustively evaluated by computer simulations and mathematical analysis, as well as validation within real test-beds deployed in controlled environments. In particular, these test-beds cover two of the main scenarios found in a SG; on one hand, an indoor electrical substation environment, implemented in a High Voltage AC/DC laboratory, and, on the other hand, an outdoor case, deployed in the Transmission and Distribution segment of a power grid. The results obtained show that SENSED-SG performs better and is more suitable for the Smart Grid than the popular ZigBee WSN approach. Full article

This paper presents a wireless sensor node (WSN) system where an electromagnetic (EM) energy harvester is utilized for charging its rechargeable batteries while the system is operational. The capability and the performance of an in-house low-frequency EM energy harvester for charging rechargeable NiMH batteries were experimentally verified in comparison to a regular battery charger. Furthermore, the power consumption of MicaZ motes, used as the WSN, was evaluated in detail for different operation conditions. The battery voltage and current were experimentally monitored during the operation of the MicaZ sensor node equipped with the EM vibration energy harvester. A compact (24.5 cm³) in-house EM energy harvester provides approximately 65 µA charging current to the batteries when excited by 0.4 g acceleration at 7.4 Hz. It has been shown that the current demand of the MicaZ mote can be compensated for by the energy harvester for a specific low-power operation scenario, with more than a 10-fold increase in the battery lifetime. The presented results demonstrate the autonomous operation of the WSN, with the utilization of a vibration-based energy harvester. Full article

In this paper four wireless sensor network operating systems are compared in terms of power consumption. The analysis takes into account the most common operating systems—TinyOS v1.0, TinyOS v2.0, Mantis and Contiki—running on Tmote Sky and MICAz devices. With the objective of ensuring a fair evaluation, a benchmark composed of four applications has been developed, covering the most typical tasks that a Wireless Sensor Network performs. The results show the instant and average current consumption of the devices during the execution of these applications. The experimental measurements provide a good insight into the power mode in which the device components are running at every moment, and they can be used to compare the performance of different operating systems executing the same tasks. Full article

Frequently, Wireless Sensor Networks (WSN) are designed focusing on applications and omitting transmission problems in these wireless networks. In this paper, we present a measurement campaign that has been carried out using one of the most commonly used WSN platforms, the micaZ from Crossbow^© . Based on these measurements, some guidelines to deploy a robust and reliable WSN are provided. The results are focused on security and environmental applications but can also be extrapolated to other scenarios. A main conclusion that can be extracted is that, from the transmission point of view, a dense WSN is one of the best choices to overcome many of the transmission problems such as the existence of a transitional region, redundance, forwarding, obstructions or interference with other systems. Full article

Wireless sensor networks (WSNs) are autonomous networks that have beenfrequently deployed to collaboratively perform target localization and classification tasks.Their autonomous and collaborative features resemble the characteristics of agents. Suchsimilarities inspire the development of heterogeneous agent architecture for WSN in thispaper. The proposed agent architecture views WSN as multi-agent systems and mobileagents are employed to reduce in-network communication. According to the architecture,an energy based acoustic localization algorithm is proposed. In localization, estimate oftarget location is obtained by steepest descent search. The search algorithm adapts tomeasurement environments by dynamically adjusting its termination condition. With theagent architecture, target classification is accomplished by distributed support vectormachine (SVM). Mobile agents are employed for feature extraction and distributed SVMlearning to reduce communication load. Desirable learning performance is guaranteed bycombining support vectors and convex hull vectors. Fusion algorithms are designed tomerge SVM classification decisions made from various modalities. Real world experimentswith MICAz sensor nodes are conducted for vehicle localization and classification.Experimental results show the proposed agent architecture remarkably facilitates WSNdesigns and algorithm implementation. The localization and classification algorithms alsoprove to be accurate and energy efficient. Full article

Patient vital sign monitoring within hospitals requires the use of non-invasivesensors that are hardwired to bedside monitors. This set-up is cumbersome, forcing thepatient to be confined to his hospital bed thereby not allowing him to move around freelywithin the hospital premises. This paper addresses the use of wireless sensor networks formonitoring patient vital sign data in a hospital setting. Crossbow MICAz motes have beenused to design a robust mesh network that routes patient data to a remote base station withinthe hospital premises. A hospital care giver can have access to this data at any point in timeand doesn’t have to be physically present in the patient’s room to review the readings. Thenetwork infrastructure nodes are self-powered and draw energy from overhead 34Wfluorescent lights via solar panels. The sensor nodes can be interfaced to a variety of vitalsign sensors such as electrocardiograms (ECGs), pulse-oximeters and blood pressure (BP)sensors. In order to verify a completely functioning system, a commercial BP/heart-ratemonitor (BPM) was interfaced to a wireless sensor node. The sensor node controls the BPMto initiate a reading, then collects the data and forwards it to the base station. An attractivegraphical user interface (GUI) was designed to store and display patient data on the basestation PC. The set-up was found to be extremely robust with low power consumption. Full article