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Performance enhancement of Vivaldi-shaped planar UWB antenna using a single-layer FSS reflector
No full textThis work proposes the design of a frequency-selective surface (FSS)-based planar monopole antenna for ultra-wideband (UWB) communication applications. The UWB response is observed by integrating a Vivaldi-shaped slot and by introducing a stepped-like pattern on the bottom edges of the radiating patch, while the back side is composed of a partial ground plane. This configuration results in a broad impedance bandwidth spanning from 3.11 to 20 GHz. For radiation performance enhancement of the proposed antenna, a single-layer UWB FSS reflector is placed beneath the antenna element at an optimized distance. The proposed FSS reflector employs a 3 × 3 array of fractal structure with a unit cell size of 12.25 × 12.25 mm2. The designed FSS reflector exhibits a linear phase response over a frequency range of 3.28 to 14 GHz, with a stop-band transmission coefficient less than -10 dB. The incorporation of the FSS reflector results in an increased gain, elevating it from 1 to 4 dBi at low-band frequencies, while at mid-band frequencies, the gain is increased from 1 to 6 dBi. The structural configuration of the proposed antenna yields directional far-field patterns, making it well-suited for UWB radar applications
A mixed passivity/small-gain theorem for Sobolev input-output stability
Get PDFA stability theorem for the feedback connection of two (possibly infinite-dimensional) time-invariant linear systems is presented. The theorem is formulated in the frequency domain and is in the spirit of combined passivity/small-gain results. It places a mixture of positive realness and small-gain assumptions on the two transfer functions to ensure a certain notion of input-output stability, called Sobolev stability (which includes the classical L2-stability concept as a special case). The result is more general than the classical passivity and small-gain theorems: strong positive realness of either the plant or controller is not required and the small gain condition only needs to hold on a suitable subset of the open right-half plane. We show that the “mixed” stability theorem is applicable in settings where L2-stability of the feedback connection is not possible, such as output regulation and disturbance rejection of certain periodic signals by so-called repetitive control
Evaluation of the Here4U Scotland application
No full textScotland's drug death statistics for 2022 were recently published showing a 21% reduction in the number of drug deaths since 2021 (National_Records_Scotland, 2023). The number reduced from 1330 to 1051 which appears a positive reflection of the work completed by agencies (third sector, charities, and NHS) to reduce drug-related fatalities (National_Records_Scotland, 2023).Despite the reduction in 2022, Scotland remains the drug death capital of Europe. It presents with 3.7 times as many related deaths in 2022 as in 2000, and those in the most deprived areas are 16 times more likely to perish from drug-related causes (National_Records_Scotland, 2023). Men are twice as likely to die from drug deaths as women and although the number of drug deaths has reduced by 21% in 2022 to 659, men are still almost 3 times more likely to die from drug use in 2022 than in 2000 (National_Records_Scotland, 2023). Women are almost 7 times as likely to die from drug use than in 2000 and although a modest reduction from 2021 of 10%, to 359 in 2022 and when compared against male drug deaths, female fatalities have risen by circa 233% over 22 years
The information environment and ecological environment perspectives: Capital market openness and firm ESG rating divergence
Get PDFAmid increasing demands for green economic growth, firms must adapt their business models and development strategies. However, most of the studies on this topic focus on examining the economic consequences of differences in firms’ environmental, social, and governance (ESG) ratings and ignore the external influences that lead to differences in information environments. This paper explores the impact of capital market openness on firm ESG rating divergence and conducts a related mechanism analysis. It is found that capital market openness creates an information environment concern effect that is generated by analysts’ concerns, audit quality, and investors’ concerns, which in turn exacerbates firm ESG rating divergence. A moderating effect test shows that the pressure created by government and public concerns regarding the ecological environment generates an ecological environment concern effect on firm ESG performance and effectively decreases the firm ESG rating divergence caused by the information concern effect
Deferred cord clamping to improve neonatal blood values. A systematic review and meta-analysis
Get PDFBackgroundPractices related to umbilical cord clamping at birth should be evidence-based. Deferred cord clamping, compared to immediate cord clamping, shows benefits for preterm neonates but this may also apply to healthy term neonates. Different blood sampling techniques are used to measure effect of deferred and immediate cord clamping.ObjectiveTo assess the statistical and effect size differences between blood biomarkers from umbilical cord and capillary blood samples of healthy term neonates following either immediate or deferred cord clamping.DesignSystematic review and meta-analysis.MethodsThe databases PubMed, Medline, CENTRAL, CINAHL and EMBASE were systematically searched. We included studies with a randomised clinical trial design comparing deferred and immediate cord clamping among healthy term neonates born by a spontaneous vaginal birth, reporting on blood biomarkers. Studies including caesarean births and premature births/neonates were excluded. Study attributes, sampling technique, blood biomarkers, mean differences, and standard deviations were extracted. The standardised mean differences (SMD) and sampling errors were calculated for effect size estimation. Meta-analyses were performed if ≥ 2 studies reported the same outcome using RevMan 5. Subgroup analyses distinguished effects from umbilical cord and capillary blood samples. Moderator tests and publication bias analyses were performed using JASP.ResultsThirteen studies were included for analysis. The biomarkers haematocrit, haemoglobin, and bilirubin were reported in ≥ 2 studies and thus eligible for pooling. No differences were found in haemoglobin (SMD 0.05, 95%CI -0.73 to 0.82) or bilirubin values (SMD 0.03, 95%CI -0.24 to 0.31) between umbilical cord blood samples collected after deferred or immediate cord clamping. Deferred cord clamping led to lower haematocrit values (SMD -0.3, 95%CI -0.53 to − 0.07). Higher haematocrit (SMD 0.67, 95%CI 0.37 to 0.97) and haemoglobin values (SMD 0.75, 95%CI 0.42 to 1.09) from capillary blood samples, collected 2 to 72 h postpartum, showed when cord clamping was deferred. No effect was found on bilirubin values (SMD 0.13, 95%CI -0.09 to 0.36) irrespective of the sampling technique.ConclusionsBlood collected after deferred umbilical cord clamping showed increased haemoglobin and haematocrit values up to 72 h after birth, opposed to bilirubin values. Clinical evaluation of blood biomarkers from the umbilical cord shows different values compared to capillary blood. Sampling time and technique therefore seem essential in estimating the effects of deferred cord clamping
Virtual Reality as a Method to Cope With Labor Pain: What Do Women Want?
Get PDFThis study aimed to determine what childbearing women want when using virtual reality as an intrapartum pain management method. Researchers performed a qualitative exploratory study using content analysis. Two focus groups were organized including pregnant women anticipating a vaginal birth and women who recently had given birth, no longer than 6 months ago. The focus groups included a 30-minute virtual reality demo. In total, 10 women participated. Five themes emerged: (1) “try, test and explore”: the need to receive information and to get acquainted with virtual reality during the antenatal period; (2) “variety and diversity in physical and digital options”: the preference for a variety in virtual content and view virtual reality as a complementary method to methods for intrapartum pain management; (3) “distraction versus focus”: virtual reality as a method to distract from pain, from the clinical context or to help them focus; (4) “comfort both physical and digital”: measures to ensure a comfortable physical and virtual experience; and (5) “birthing partner”: the potential need to include partners. This study is an essential step informing the development, implementation, and research of labor-specific virtual reality and informing antenatal healthcare providers when offering women virtual reality as intrapartum pain management
Young men and violence against women prevention: Exploring reactions and emotions
Get PDFThere has been an increase in attention paid to the need for prevention work in response to the pervasive issue of violence against women (VAW) which includes femicide, rape and other violence. The need to directly address men and boys in prevention work has led to a focus on improving the impact of this work. Previous research has shown that young men often feel discomfort in response to these messages however little more is known about these feelings. This briefing paper outlines the key findings from a project that interviewed 20 young men (18 to 25 years) who live in Scotland to ask about their reactions to VAW prevention messages focusing on how these make them feel and how prevention messages could be improved
Interaction Effects in the Cross-Section of Country and Industry Returns
Get PDFWe comprehensively examine the interaction effects in the cross-sectional predictability of country and industry returns. Using nearly five decades of data from 68 countries, we construct all possible double-sorted portfolios based on 44 portfolio characteristics and uncover numerous significant interactions. An out-of-sample value-weighted strategy that selects the top long-short country (industry) interactions generates a monthly World CAPM alpha of 0.33% (0.62%) with a Sharpe ratio of 0.58 (0.75). The strongest interactions stem from implementing momentum and technical analysis signals in small and illiquid countries or industries. Furthermore, the return patterns mainly emanate from frontier and weakly integrated markets—highlighting the role of market frictions and segmentation in the occurrence of abnormal returns. Consistent with these interpretations, the interactions decline over time as global markets mature and become more integrated
Dynamic service of geographically dispersed time-sensitive demands
Get PDFThis paper presents a new framework that models the novel dynamic vehicle dispatch problem with holding costs (DVDPHC), which focuses on serving stochastic demands at geographically dispersed locations in a timely manner. This framework is applicable, among others, to the post-disaster ambulance bus routing problem, where an ambulance bus must pick up (urgent) patients at geographically dispersed locations and bring them to a centrally-located hospital as quickly as possible. Solving the DVDPHC requires a dynamic decision-making rule at each decision moment for which demands to serve at the current location, and where to direct the vehicle next. We propose a heuristic based on approximate dynamic programming combined with a neural network (ADP-NN) for effectively solving the DVDPHC. Numerical experiments demonstrate that our proposed method is fast, scalable and robust. Furthermore, it keeps up with computationally heavy direct lookahead (DLA) benchmarks on 120 large representative instances, achieving on average 12.77% total cost improvement. Numerical analysis also reveals that our proposed method exhibits complex self-learned flexible behavior, such as waiting near locations in anticipation of new demand
The energy-balance method for optimal control in renewable energy applications
Get PDFA theoretical method is presented, called the energy-balance method, for maximising the energy extracted from a renewable energy converter in terms of determination of an optimal control. The method applies to control systems specified by linear graphs, and graph-theoretic techniques are employed. The method simplifies a number of optimal control problems by essentially expressing the performance objective — maximising energy extraction — in terms of an equivalent objective involving fewer variables, thereby reducing the complexity of the optimisation. As illustrated, in certain cases the optimal control problem may be reduced to one solvable by elementary calculus techniques. The theory is illustrated with examples from solar, wave and wind applications
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