Evaluation of Misalignment Effect in Vehicle-to-Vehicle Visible Light Communications: Experimental Demonstration of a 75 Meters Link

The use of visible light communications technology in communication-based vehicle applications is gaining more and more interest as the research community is constantly overcoming challenge after challenge. In this context, this article addresses the issues associated with the use of Visible Light Communications (VLC) technology in Vehicle-to-Vehicle (V2V) communications, while focusing on two crucial issues. On the one hand, it aims to investigate the achievable communication distance in V2V applications while addressing the least favorable case, namely the one when a standard vehicle rear lighting system is used as a VLC emitter. On the other hand, this article investigates another highly unfavorable use case scenario, i.e., the case when two vehicles are located on adjacent lanes, rather than on the same lane. In order to evaluate the compatibility of the VLC technology with the usage in inter-vehicle communication, a VLC prototype is intensively evaluated in outdoor conditions. The experimental results show a record V2V VLC distance of 75 m, while providing a Bit Error Ratio (BER) of 10−7–10−6. The results also show that the VLC technology is able to provide V2V connectivity even in a situation where the vehicles are located on adjacent lanes, without a major impact on the link performances. Nevertheless, this situation generates an initial no-coverage zone, which is determined by the VLC receiver reception angle, whereas in some cases, vehicle misalignment can generate a BER increase that can go up to two orders of magnitude.

Design and Test of a Miniature Hydrogen Production Integrated Reactor

A detailed study of the experimental issues involved in the design and operation of a methanol steam microreformer is presented in this paper. Micromachining technology was utilized to fabricate a metallic microchannel block coupling the exothermic and endothermic process. The microchannel block was coated with a Pd/ZnO catalyst in the reforming channels and with Pd/Al2O3 in the combustion channels by washcoating. An experimental system had been designed and fine-tuned allowing estimation of the heat losses of the system and to compensate for them by means of electric heating cartridges. In this way, the heat necessary for the reforming reaction is provided by methanol combustion, thanks to the temperature and flow cascade controller we developed. Thus, the coupling of both reactions in a block of microchannels without the interference caused by significant heat loss due to the small size of the laboratory microreactor could be studied. Runs of this microreformer device were carried out, varying the deposited catalyst amount, methanol steam reforming temperature and space velocity. When the reforming reaction was compensated by the combustion reaction and the heat losses by the electric heating, an almost isothermal behavior of the microchannel reactor was observed. In the less favorable case, with a 460 mg catalyst load, ΔTMSR was about 8 K and ΔTCOMB was about 16 K. This confirmed good coupling of the methanol steam reforming and the methanol combustion.

Evading resistance to gene drives

Gene drives offer the possibility of altering and even suppressing wild populations of countless plant and animal species, and CRISPR technology now provides the technical feasibility of engineering them. However, population-suppression gene drives are prone to select resistance, should it arise. Here, we develop mathematical and computational models to identify conditions under which suppression drives will evade resistance, even if resistance is present initially. Previous models assumed resistance is allelic to the drive. We relax this assumption and show that linkage between the resistance and drive loci is critical to the evolution of resistance and that evolution of resistance requires (negative) linkage disequilibrium between the two loci. When the two loci are unlinked or only partially so, a suppression drive that causes limited inviability can evolve to fixation while causing only a minor increase in resistance frequency. Once fixed, the drive allele no longer selects resistance. Our analyses suggest that among gene drives that cause moderate suppression, toxin-antidote systems are less apt to select for resistance than homing drives. Single drives of moderate effect might cause only moderate population suppression, but multiple drives (perhaps delivered sequentially) would allow arbitrary levels of suppression. The most favorable case for evolution of resistance appears to be with suppression homing drives in which resistance is dominant and fully suppresses transmission distortion; partial suppression by resistance heterozygotes or recessive resistance are less prone to resistance evolution. Given that it is now possible to engineer CRISPR-based gene drives capable of circumventing allelic resistance, this design may allow for the engineering of suppression gene drives that are effectively resistance-proof.

The greenhouse effect and its impacts on environment

The buildup of so-called «greenhouse gases» in the atmosphere - CO2 in particular-appears to be having an adverse impact on the global climate. This article briefly reviews current expectations with regard to physical and biological effects, their potential costs to society, and likely costs of abatement. For a «worst case» scenario it is impossible to assess, in economic terms, the full range of possible non-linear synergistic effects. In the «most favorable» case, however, it seems likely that the impacts are within the «affordable» range, at least in the industrialized countries of the world. In the «third world» the notion of affordability is of doubtful relevance, making the problem of quantitative evaluation almost impossible.

Professional substitutability and additional education of engineering graduates

The paper deals with the psycho-didactic problems arising in employing engineering graduates for positions that dont meet either the level or the area of training acquired at a technical higher school. Foreign authors refer to this socio-didactic phenomenon as professional substitutability. It is stressed that in a market-based society professional substitutability is, to some extent, predictable and inevitable. For that reason, the adaptation of university graduates to taking up job vacancies is becoming highly relevant both for young specialists and for their potential employers, as well as for the system of additional education. It is shown that professional substitutability may be of two kinds: vertical and horizontal. Vertical substitutability refers to the situations when graduates with a specific degree (specialist, bachelor, master) in a specific field and subject of training are employed according to the area of their higher school, but the job qualification doesnt match the graduates qualification (it may be either higher or lower). Horizontal substitutability refers to the processes when the graduate, due to some extraordinary circumstances, is to take up a vacancy that is fully in line with the university qualification; however (in a more favorable situation) it doesnt match the university training, although that major belongs to the same field of training. In a less favorable case, the graduate takes up a position requiring the qualification that may differ from the field of university training. The paper outlines the content and the components of the adaptation period needed for the young employee, when he/she is to go through psychological and professional subject and industry specific functional adaptation independently to bridge the knowledge gap and acquire professional competencies. Usually, the young specialist is to undergo additional training (in industry, technology, science), take a refresher course or enter a masters degree or a post-graduate program. In the paper there is a summary table demonstrating the kinds and types of additional education for young specialists taking up job vacancies according to different types of horizontal and vertical professional substitutability. This table (which, actually, is a morphological matrix) can be used as a navigator for engineering graduates when taking up a job vacancy. It can be also applied by institutions of additional education to develop educational programs and curricula for refreshment and requalification courses.

Determinants of brain tumor malpractice litigation outcome and indemnity payments: a 29-year nationwide analysis

OBJECTIVEMedical malpractice litigation is a significant challenge in neurosurgery, with more than 25% of a neurosurgeon’s career on average spent with an open malpractice claim. While earlier research has elucidated characteristics of litigation related to brain tumor treatment, factors impacting outcome and indemnity payment amount are incompletely understood.METHODSThe authors identified all medical malpractice cases related to brain tumors from 1988 to 2017 in VerdictSearch, a database of 200,000 cases from all 50 states. The outcome for each case was dichotomized from the perspective of the defendant physician as favorable (defendant victory) or unfavorable (plaintiff victory or settlement). Indemnity payments were recorded for cases that resulted in settlement or plaintiff victory. Univariate regression was used to assess the association between case characteristics and case outcome as well as indemnity payment amount. Subsequently, significant variables were used to generate multivariate models for each outcome. Statistical significance was maintained at p < 0.05.RESULTSA total of 113 cases were analyzed, resulting most commonly in defendant (physician) victory (46.9%), followed by settlement and plaintiff victory (both 26.5%). The most common specialty of the primary defendant was neurosurgery (35.4%), and the most common allegation was improper diagnosis (59.3%). Indemnity payments totaled $191,621,392, with neurosurgical defendants accounting for $109,000,314 (56.9%). The average payments for cases with a plaintiff victory ($3,333,654) and for settlements ($3,051,832) did not significantly differ (p = 0.941). The highest rates of unfavorable outcomes were observed among radiologists (63.6%) and neurosurgeons (57.5%) (p = 0.042). On multivariate regression, severe disability was associated with a lower odds of favorable case outcome (OR 0.21, p = 0.023), while older plaintiff age (> 65 years) predicted higher odds of favorable outcome (OR 5.75, p = 0.047). For 60 cases resulting in indemnity payment, higher payments were associated on univariate analysis with neurosurgeon defendants (β-coefficient = 2.33, p = 0.017), whether the plaintiff underwent surgery (β-coefficient = 2.11, p = 0.012), and the plaintiff experiencing severe disability (β-coefficient = 4.30, p = 0.005). Following multivariate regression, only medical outcome was predictive of increased indemnity payments, including moderate disability (β-coefficient = 4.98, p = 0.007), severe disability (β-coefficient = 6.96, p = 0.001), and death (β-coefficient = 3.23, p = 0.027).CONCLUSIONSNeurosurgeons were the most common defendants for brain tumor malpractice litigation, averaging more than $3 million per claim paid. Older plaintiff age was associated with case outcome in favor of the physician. Additionally, medical outcome was predictive of both case outcome and indemnity payment amount.

Soiling Loss Rate Measurements of Photovoltaic Modules in a Hot and Humid Desert Environment

Power generation from renewable energy sources, in particular solar photovoltaics (PV), has become extremely attractive thanks to its very low levelized cost of electricity (LCoE). In desert-like environments, the energy yield is drastically reduced due to dust accumulation. While effective and affordable cleaning strategies can be implemented in large, MW-size PV power plants, soiling remains an economic and logistic challenge. In this article, we analyze the soiling loss rates of PV modules for different tilt angles measured during a period of 15 months in the Western Region of Saudi Arabia. We observe a strong correlation between weather parameters like humidity and wind speed and the mechanism of dust accumulation. Our measurements show that, for specific weather conditions, soiled modules undergo a partial cleaning process. As a consequence, and for the first time, the soiling loss rates are shown to have a clear dependence on the current soiling state of the modules, with clean modules soiling twice as fast as soiled ones. This dependency is a key for predicting the correct cleaning frequency of a PV power plant. Finally, the results obtained for vertically mounted modules (90 deg), where dust accumulation is negligible, point to a favorable case for the use of bifacial PV modules.

Evading resistance to gene drives

Gene drives offer the possibility of altering and even suppressing wild populations of countless plant and animal species, and CRISPR technology now provides the technical feasibility of engineering them. However, population-suppression gene drives are prone to select resistance, should it arise. Here we develop mathematical and computational models to identify conditions under which suppression drives will evade resistance, even if resistance is present initially. Previous models assumed resistance is allelic to the drive. We relax this assumption and show that linkage between the resistance and drive loci is critical to the evolution of resistance and that evolution of resistance requires (negative) linkage disequilibrium between the two loci. When the two loci are unlinked or only partially so, a suppression drive that causes limited inviability can evolve to fixation while causing only a minor increase in resistance frequency. Once fixed, the drive allele no longer selects resistance. Our analyses suggest that among gene drives that cause moderate suppression, toxin-antidote systems are less apt to select for resistance than homing drives. Single drives of moderate effect might cause only moderate population suppression, but multiple drives (perhaps delivered sequentially) would allow arbitrary levels of suppression. The most favorable case for evolution of resistance appears to be with suppression homing drives in which resistance is dominant and fully suppresses transmission distortion; partial suppression by resistance heterozygotes or recessive resistance are less prone to resistance evolution. Given that it is now possible to engineer CRISPR-based gene drives capable of circumventing allelic resistance, this design may allow for the engineering of suppression gene drives that are effectively resistance-proof.

Numerical analysis of the mine blast action on an armored vehicle for different V-hull geometries

The main objective of this research is to develop a numerical model of vehicle damage caused by an explosion of a mine, as well as to find the most favorable case of V-hull geometry and to point out a possible solution for mitigating the effects of mine explosion on an armored vehicle. Seven different V-hull geometries were considered and structure damage analysis was performed for all seven options. Also, the mass change for different geometries was analyzed. The effect of the mine explosion on the target structure was analyzed using the overpressure function according to the empirical CONWEP model, using Abaqus / Explicit software. An example of an explosion of 8 kg of Composition B acting on a vehicle with a total mass of 8000 kg was analyzed. The vehicle has two main parts - the cabin with mass of 6 t and a V-hull of mass of 2 t. The V-shaped hull in all the examples shown is made of 10 mm thick plates of Hardox 400 steel. The position of the explosive charge is the same for all geometry examples and is 0.6 m below the center of the vehicle. After analysis of the obtained results the most favorable V-hull geometry is determined. The guidelines for the further work and model improvement are suggested.

A gyógyszer által indukált állcsontnecrosis-kockázat mértékének meghatározása az általános fogorvosi gyakorlatban

Medication-related osteonecrosis of the jaw may appear as adverse effect in antiresorptive therapy. Its successful treatment is challenging. We aimed to gather the systemic and local factors playing a role in etiology, published after its recognition. Risk factors were collected from the PubMed database 1998–2018. The three main groups of risk patients are: patients starting, patients having antiresorptive therapy, osteonecrosis diagnosed patients. The dentist must recognize risk factors, determine appropriate treatment plan and frequency of check-ups. Oncological disease treated intravenously means the greatest risk. Further systemic risk factors are: supportive therapies, concomitant disease, way of life, individual factors. Local risk factors may be: dentoalveolar surgery, periapical and periodontal inflammation, ill-fitting denture, presence of some anatomical structures. The accumulation of risk factors determines the probability of the manifestation of osteonecrosis. The most favorable case is patient starting antiresorptive therapy with a dental status needing no treatment. Orv hetil. 2019; 160(7): 243–251.