bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress-Induced Birefringence in Gradient-Index Structures Fabricated by Ion-Exchange
Authors: Tomkinson Todd H. , Saxer Christopher E.
Published: February 2023

This paper examines an axial gradient-index (GRIN) glass sample produced by ion-exchange in the glass system:

0.704

SiO

2

+
0.044

Al

2

O
3

+
(
0.252
−
χ
(
z
)
)

Na

2

O
+
χ
(
z
)

Li

2

O

(where χ(z) represents the degree of exchange versus position, z), with the intention of determining χ(z) from a measurement of the index profile, n(z). Due to the ion-exchange conditions, the sample contains “frozen-in” stresses that strain the glass network, preventing it from obtaining its free expansion volume. The resulting volume change causes an additional birefringent index change. Therefore, when the index profile of the sample, n(z), is measured, it is necessary to take into account the sample’s birefringence to accurately determine the exchange profile, χ(z).

The gradient’s index change, Δn(z), (where, Δn(z)=n(z)-nb, and nb is the base index), can be determined to accuracies reaching 0.03%. This paper shows that when frozen stresses are not taken into consideration, errors in determining χ(z) can reach 1.8%. However, it is shown that by also measuring the sample’s birefringence, determination of χ(z) may become more accurate.
Modified angular spectrum algorithm for the propagation of partially coherent beams in optical systems
Authors: Zhong Zhicheng , Zhao Shuai
Published: February 2023

A modified angular spectrum algorithm is presented for the diffraction calculation of partially coherent beams propagating in optical systems. The proposed algorithm can directly calculate the cross-spectral density of partially coherent beams at each surface of the optical system and possesses much higher computational efficiency for low coherent beams compared with that of the common modal expansion methods. Then, a Gaussian–Schell model beam propagating in a double-lens array homogenizer system is introduced to carry out a numerical simulation. Results show that the proposed algorithm can obtain an identical intensity distribution as the selected modal expansion method but with a much higher speed, thus verifying its accuracy and high efficiency. However, it’s worth noting that the proposed algorithm is only suitable to the optical systems in which the partially coherent beams and optical components have no coupling effects in the x and y directions and can be dealt with individually.
Optical-cryptographic scheme based on an image self-disordering algorithm
Authors: Mosso Edward
Published: February 2023

This paper demonstrates a novel optical-cryptographic system based on a new image self-disordering algorithm (ISDA). The cryptographic stage is based on an iterative procedure using an ordering sequence from the input data to produce diffusion and confusion keys. Our system uses this approach over plaintext and optical cipher from a 2f-coherent processor working with two random phase masks. Since the keys used for encryption depend on the initial input information, the system is resistant to common attacks such as the chosen-plaintext attack (CPA) and the known-plaintext attack (KPA). In addition, since the ISDA operates the optical cipher, the 2f processor linearity is destroyed, producing an enhanced ciphertext in phase and amplitude, improving optical encryption protection. This new approach offers higher security and efficiency than other reported systems. We perform security analyses and validate the feasibility of this proposal by synthesizing an experimental keystream and performing color image encryption.
Mid-infrared quasi-parametric chirped-pulse amplification based on Sm:LGN crystals
Authors: Ding Yufang , Liu Jinsheng , Gu Xingbin , Yuan Peng , Ma Jingui
Published: February 2023

We numerically demonstrate highly efficient mid-infrared quasi-parametric chirped-pulse amplification (QPCPA) based on a recently developed Sm3+-doped La3Ga5.5Nb0.5O14 (Sm:LGN) crystal. At pump wavelength around 1 µm, the broadband absorption of Sm3+ on idler pulses can enable QPCPA for femtosecond signal pulses centered at 3.5 or 5 µm, with a conversion efficiency approaching the quantum limit. Due to suppression of back conversion, such mid-infrared QPCPA exhibits robustness against phase-mismatch and pump-intensity variation. The Sm:LGN-based QPCPA will provide an efficient approach for converting currently well-developed intense laser pulses at 1 µm to mid-infrared ultrashort pulses.
Perfect excitation and attenuation-free propagation of graphene surface polaritons under optical admittance matching
Authors: Sun Lixun , Li Shuang , Xiao Yuyang , Lu Fanfan , Zhang Wending , Mei Ting
Published: February 2023

Graphene supports both transverse magnetic and electric modes of surface polaritons due to the intraband and interband transition properties of electrical conductivity. Here, we reveal that perfect excitation and attenuation-free propagation of surface polaritons on graphene can be achieved under the condition of optical admittance matching. With both vanished forward and backward far-field radiation, incident photons are fully coupled to surface polaritons. This requires an exact match between the admittance difference of sandwiching media and the conductivity of graphene, resulting in no decay of propagating surface polaritons. The dispersion relation has a completely different line shape for structures that support compared to those that do not support admittance matching. This work promotes complete comprehension of the excitation and propagation behaviors of graphene surface polaritons and may further inspire ideas for research on surface waves on two-dimensional materials.
Investigation of the electro-optic effect in high-Q 4H-SiC microresonators
Authors: Wang Ruixuan , Li Jingwei , Cai Lutong , Li Qing
Published: February 2023

Silicon carbide (SiC) recently emerged as a promising photonic and quantum material owing to its unique material properties. In this work, we carried out an exploratory investigation of the Pockels effect in high-quality-factor (high-Q) 4H-SiC microresonators and demonstrated gigahertz-level electro-optic modulation for the first time. The extracted Pockels coefficients show certain variations among 4H-SiC wafers from different manufacturers, with the magnitudes of r13 and r33 estimated to be in the range of (0.3–0.7) pm/V and (0–0.03) pm/V, respectively.
High-velocity upward shifts in vegetation are ubiquitous in mountains of western North America
Authors: Kellner James R. , Kendrick Joseph , Sax Dov F.
Published: February 2023

The velocity of climate change and its subsequent impact on vegetation has been well characterized at high elevations and latitudes, including the Arctic. But whether species and ecosystems are keeping pace with the velocity of temperature change is not as well documented. Some evidence indicates that species are less able to keep pace with the velocity of climate change along elevational gradients than latitudinal ones. If substantiated this finding could warrant reconsideration of a current cornerstone of conservation planning. Here we use 27 years of high-resolution satellite data to quantify changes in vegetation cover across elevation within nine mountain ranges in western North America, spanning tropical Mexico to subarctic Canada and from coastal California to interior deserts. Across these ranges we show a uniform pattern at the highest elevations in each range, where increases in vegetation have occurred ubiquitously over the past three decades. At these highest elevations, the realized velocity of vegetation varies among mountain ranges from 19.8–112.8 m · decade-1 (mean = 67.3 m · decade-1). This is equivalent, with respect to gradients in temperature, to a 14.4–104.3 km · decade-1 poleward shift (mean = 56.1 km · decade-1). This realized velocity is 4.4 times larger than previously reported for plants, and is among the fastest rates predicted for the velocity of climate change. However, in three of the five mountain ranges with long-term climate data, realized velocities fail to keep pace with changes in temperature, a finding with important implications for conservation of biological diversity.
Implementation of a Level III neonatal intensive care unit was associated with reduced NICU mortality in a resource limited public tertiary care hospital in Guyana, South America
Authors: Singh Sara , Scott Winsome , Yeager Caitlin , Rambaran Madan , Singh Narendra C. , Nelin Leif D.
Published: February 2023

Neonatal mortality is a significant contributor to child mortality, and there is increasing interest in low resource settings to implement neonatal intensive care practices to lower neonatal mortality. In Guyana, South America neonatal mortality remains relatively high. At Georgetown Public Hospital Corporation (GPHC), the only tertiary referral hospital in Guyana, a Level III NICU was developed starting in January, 2012 with full implementation in September, 2015. In this study, we report the association of the implementation of a Level III NICU with in-hospital neonatal survival at GPHC. Using an observational study design, available data were collected from January 1, 2015 through September 30, 2020. During the study period, there were 30,733 deliveries at GPHC and 4,467 admissions to the NICU at GPHC. There were no significant changes in the numbers of births or NICU admissions during the time of the study. The survival rate for patients admitted to the NICU was ~64% during the first 3 quarters of 2015 with most deaths were caused by sepsis or respiratory failure. By the last quarter of 2015, the NICU survival rate increased dramatically and has been sustained at ~87% (p<0.0001). The inborn mortality rate at GPHC, calculated as a percentage of all live births at GPHC, was 2.9% prior to the full implementation of the NICU and was 1.4% after the full implementation of the NICU (p<0.0001). These findings suggest that the implementation of a Level III NICU at GPHC was associated with an improvement in survival to NICU discharge in a resource limited setting.
Telemedicine and its acceptance by patients with type 2 diabetes mellitus at a single care center during the COVID-19 emergency: A cross-sectional observational study
Authors: Sartore Giovanni , Caprino Rosaria , Ragazzi Eugenio , Lapolla Annunziata
Published: February 2023

Introduction

When Italy was placed under lockdown to contain the COVID-19 pandemic from 9 March to 18 May 2020, alternative approaches to delivering care—such as telemedicine—were promoted for patients with chronic diseases like diabetes mellitus (DM). The aim of this study was to analyze patients’ perception of, and satisfaction with the telehealth services offered during the COVID-19 emergency at an outpatient diabetes care unit in Italy.

Methods

A cross-sectional survey was conducted on 250 patients with type 2 diabetes mellitus who regularly attended our diabetes care unit. Data were collected by means of telephone interviews, asking patients how they perceived the telehealth services, and their satisfaction with the televisit and computer-based care. A standardized questionnaire was administered: there were questions answered using a five-point Likert scale, and one open-ended question. Patients’ demographic, anthropometric and biological data were collected from their medical records. Correlations between patients’ characteristics, their perception of telemedicine, and their satisfaction with the televisit were examined. Spearman’s rank-order correlation coefficient ρ (rho) and Kendall’s rank correlation coefficient τ (tau) were used as nonparametric measures of the strength of the association between the scores obtained for the two ordinal variables, Perception and Satisfaction, and between other clinical parameters. Principal component analysis (PCA) was also used to assess overall links between the variables.

Results

Almost half of the interviewees expressed a strongly positive perception of the medical services received, and more than 60% were very satisfied with the telehealth service provided during the COVID-19 emergency. There was a strong correlation between patients’ perception and satisfaction ratings (p<0.0001). Duration of disease showed a significant positive correlation with patients’ satisfaction with their medical care. By means of PCA, it was found that BMI correlated inversely with both perception and satisfaction. Following a qualitative analysis of patients’ answers to the open-ended question, contact with their specialist was important to them: it was reassuring and a source of scientifically correct information about their disease and the association between COVID-19 and diabetes.

Conclusions

Based on our telephone interviews, patients appreciated the telehealth approach and were satisfied with it, regardless of the characteristics of their disease. Telemedicine proved essential to avoid interrupting the continuity of care, and therefore had not only clinical, but also psycho-social repercussions.
Water temperature dynamics in a headwater forest stream: Contrasting climatic, anthropic and geological conditions create thermal mosaic of aquatic habitats
Authors: Bois Paul , Beisel Jean-Nicolas , Cairault Alban , Flipo Nicolas , Leprince Corentin , Rivière Agnès
Published: February 2023

The thermal regime of streams is a relevant driver of their ecological functioning. As this regime is presently submitted to numerous alterations (among others, impoundments, and climate change), it seems important to study both their effects and potential recovery from the latter. Thus, we investigated the surface and hyporheic water temperature along a small headwater stream with contrasting environmental contexts: forest landscape, open grassland landscape without riparian vegetation, several artificial run-of-the-river impoundments and one discharge point of a by-pass impoundment. The main objectives were to study the influence of these contrasting contexts on surface and subsurface water temperature at a local scale. Contrasting contexts were supposed to create effects on both surface and hyporheic thermal regimes at a local scale. Differences of thermal regimes between surface and hyporheos were expected, as well as between geological contexts. Sensors located at multiple stations allowed monitoring of stream and hyporheos temperature along the stream, while comparison with adjacent reference stream allowed for surface water thermal regime benchmark. Impoundments and landscapes significantly influenced stream thermal regime at a local scale (impoundments created up to +3.7°C temperature increase in average). Their effect on hyporheos thermal regime was less marked than the ones generated by solar radiation or geological features. Hyporheos thermal regime varies from stream one by temperature dynamics delay (up to 18h) and decrease (up to -7°C between surface and hyporheos temperature in average). These coupled effects create a mosaic of thermal habitats, which could be used for river biodiversity preservation and restoration.
Sadness, hopelessness and suicide attempts in bullying: Data from the 2018 Iowa youth survey
Authors: Newman Kaela L. , Alexander Daniel S. , Rovers John P.
Published: February 2023

Background

Bullying in schools is a common problem that can have significant consequences on the mental health of both bullies and victims of bullying. Some estimates suggest that 30% of American youth are bullied. Self-reported incidence of depression, anxiety, and suicide attempts has been correlated with bullying. Victims may also suffer from a variety of somatic complaints such as headache, sleep disorders, and others. Youth surveys undertaken by Education or Public Health Departments in most US states are an underutilized resource in evaluating the problem and any consequences.

Objective

The objective of this study was to explore the association of being involved in bullying either as a victim and/or a bully on mental health and suicide ideation by analyzing data from the 2018 Iowa Youth Survey. The results will then be applied to the published anti-bullying literature to make suggestions for how anti-bullying programs may be designed.

Methods

Data were obtained from the 2018 Iowa Youth Survey (IYS), which is a cross-sectional survey of 6th, 8th and 11th grade students. We chose two mental health questions as dependent variables and used a multivariable logistic regression analysis to evaluate the correlation between the two dependent variables and ten types of bullying included in the IYS. Since some respondents in the IYS were prescribed psychotropic medications to help with feeling angry, anxious, nervous, or sad, we adjusted for the use of psychotropic medication in our analysis. Similarly, the literature suggests that some students are both bullies and victims (bully-victims). Accordingly, we also adjusted for bully-victims.

Results

Unadjusted Odds Ratios (ORs) showed that not all forms of bullying were correlated with a significant risk of mental distress. Physical bullying had comparatively little association (ORs < 1 or overlapped 1), while identity bullying on sexual orientation or gender identity or sexual joking was consistently correlated with significant ORs for feeling sad or hopeless and attempting suicide (ORs 1.40–2.84). Cyberbullying (ORs 1.32–1.70) and social bullying (ORs < 1–2.21) were correlated with mental distress with ORs generally between physical and identity bullying. When adjusting for medication use or bully-victim status, adjusted ORs (aORs) were generally lower than unadjusted ORs.

Conclusions

Not all types of bullying were significantly correlated with feeling sad or hopeless or attempting suicide. Being able to evaluate the specific associations of different types of bullying may have implications for teachers or policy makers hoping to implement bullying mitigation strategies in their schools.
Reviewing the potentials of MMOGs as research environments: A case study from the strategy game Travian
Authors: Müller Siegfried , Ghawi Raji , Pfeffer Jürgen
Published: February 2023

Massively Multiplayer Online Games (MMOGs) provide many opportunities for scientists. Previous research ranges from personality trait prediction to alternative cancer treatments. However, there is an ongoing debate on whether these virtual worlds are able to represent real world scenarios. The mapping of online and offline findings is key to answering this question. Our work contributes to this discussion by providing an overview of the findings from network-based team and leadership research and by matching them with concrete results from our MMOG case study. One major finding is that team size matters. We show that high diversity in the type of teams is a major challenge, especially when combined with the immense amount of data in MMOGs. In our work, we discuss these issues and show that a well-grounded understanding of the data and the game environment makes it possible to overcome these limitations. Besides the team size, the aggregation periods play an important role. Regarding MMOGs as research environments, we show that it is important to pay close attention to the specific game-related contexts, the incentive structures, and the downside risks. Methodologically, we apply support and communication networks to show the influence of certain group-based measures (e.g., density, transitivity) as well as leadership-centered characteristics (e.g., k-core, group centrality, betweenness centralization) on team performance. Apart from our findings on centralization in communication networks, we are able to demonstrate that our results confirm the theoretical predictions which suggest that the behavioral patterns observed in MMOG teams are comparable to those observed in offline work teams.
In Ethiopia’s Kutaber district, does community-based health insurance protect households from catastrophic health-care costs? A community- based comparative cross-sectional study
Authors: Kassa Ayesheshim Muluneh
Published: February 2023

Objective

Every health system needs to take action to shield households from the expense of medical costs. The Ethiopian government implemented community-based health insurance (CBHI) to protect households from catastrophic health care expenditure (CHE) and enhance the utilization of health care services. The impact of CBHI on CHE with total household expenditure and non-food expenditure measures hadn’t been studied, so the study aimed to evaluate the impact of CBHI on CHE among households in Kutaber district, Ethiopia.

Methods

A total of 472 households (225 insured and 247 uninsured) were selected by multistage sampling techniques. Households total out-of-pocket (OOP) health payments ≥10% threshold of total household expenditure or ≥40% threshold of household non-food expenditure categorized as CHE. The co-variants for participation in the CBHI scheme were estimated by using a probit regression model. A propensity score matching analysis was used to determine the impact of CBHI on CHE. A Chi-square (χ2) test was computed to compare CHE between insured and uninsured households.

Results

The magnitude of CHE was 39.1% with total household expenditure and 1.8% with non-food expenditure measures among insured households. Insured households were 46.3% protected from CHE when compared to uninsured households with total household expenditure measures and 24.2% to 25% with non-food expenditure measures.

Conclusion

The magnitude of CHE was lower among CBHI-enrolled households. CBHI is an effective means of financial protection benefits for households as a share of total household expenditure and non-food expenditure measures. Therefore, increasing the upper limits of benefit packages, minimizing exclusions, and CBHI scale-up to uninsured households is essential.
The impact of the COVID-19 pandemic and the expansion of free vaccination policy on influenza vaccination coverage: An analysis of vaccination behavior in South Korea
Authors: Yeo Muhan , Seo Jeongmin , Lim Juwon
Published: February 2023

Background

Annual vaccination for influenza is globally recommended for some prioritized groups due to its high morbidity and mortality. Until 2019, South Korea has provided free influenza vaccination to children aged ≤12, adults aged ≥65, and pregnant women to enhance vaccination coverage. In 2020, with the COVID-19 pandemic, free flu vaccination was temporarily broadened to adults aged 62–64 and children aged 13–18. We analyzed the trends in influenza vaccination coverages in South Korea and evaluated the impact of the COVID-19 pandemic and the expansion of the free vaccination policy on influenza vaccination coverage.

Methods

We conducted a cross-sectional study with nationwide survey data from Korea National Health and Nutrition Examination Survey (KNHANES). We evaluated the trends in influenza vaccination coverages of target populations from 2010 to 2020. Influenza vaccination coverages of children aged 13–18, adults aged 62–64, and adults aged ≥65 were compared between 2019 and 2020.

Results

In total, 72,443 individuals were analyzed. From 2019 to 2020, with the expansion of free influenza vaccination and the COVID-19 pandemic, the vaccination coverage of children aged 13–18 increased from 27.8% to 43.5% (P<0.001) but that of people aged 62–64 showed insignificant change from 57.4% to 51.5% (P = 0.266). Furthermore, the vaccination coverage in adults aged ≥65 declined from 87.2% to 79.1% (P<0.001).

Conclusion

In 2020, along with COVID-19 outbreaks, a decline of influenza vaccination coverage in older adults was observed regardless of free immunizations. It is likely due to behavioral changes to reduce the risk of COVID-19 transmission. This is supported by a greater reduction of influenza vaccination coverage in regions with higher COVID-19 outbreaks, as well as by South Korea’s high medical accessibility and highly congested medical facilities. To sustain a high level of vaccination coverage of high-risk population during epidemics, additional efforts beyond free vaccination policies should be implemented.
Somewhere under the rainbow: LGBTQ youth and school climate in Portugal
Authors: Fernandes Telmo , Alves Beatriz , Ioverno Salvatore , Gato Jorge
Published: February 2023

This article presents a narrative review about the situation of lesbian, gay, bisexual, trans, queer and questioning (LGBTQ) youths in Portuguese schools. The Portuguese context and social climate towards LGBTQ people were presented and a review of existing legislation, policies and interventions focusing on LGBTQ youth was conducted. Results from social science research with this population were examined and complemented with data from a recent survey. Pervasiveness of prejudice and discrimination and the concurrent need to manage the visibility of LGBTQ identities both in school context and in the family were confirmed. Support from school is not always guaranteed, and evidence of anti-bullying policies that explicitly mention sexual orientation and gender identity is still scarce. Some implications for future practice and research are drawn.
Cohesion in Finnish EFL essays
Authors: Niitemaa Marja-Leena
Published: February 2023

The study investigated cohesion in Finnish upper-secondary school
EFL learners’ essays (N=46). Cohesive devices were digitally identified
using TAACO 2.0.4, and robust correlations were run to examine how the
devices related to human-rated holistic essay quality. The analyses found
that the two most important predictors of writing quality were the use of
modifying adverbs and adverbials as referential devices across paragraphs,
and a wide array of connectives to organise the text. Further, the writing
sessions were video-recorded to examine the role of consulting digital
sources in cohesionbuilding. The recorded data suggested that consulting
online dictionaries and informational pages assisted cohesion-building if
the writer possessed adequate vocabulary knowledge and computer skills and
knew how to exploit the sources efficiently. Pedagogically, the findings
indicated that learners need more instruction and practice not only on
writing cohesive texts but also on how to search for information and lexis
effectively.
The master’s element in initial teacher training: what is its value?
Authors: Merchant Georgina , Bubb Sara
Published: February 2023

A theory–practice divide has beset initial teacher training (ITT) for many decades. In England, there are multiple ways to gain qualified teacher status, which can be broadly categorised into school-led or university-led, with underlying arguments about the relative importance of theory and practice, and how far learning to teach should be seen as an apprenticeship. Government policy has moved towards more prescription with its ITT Core Content Framework, a curriculum that suggests that there is a right way to learn to teach. In this climate, it is important to establish what value universities – and, in particular, the master’s element of the Postgraduate Certificate in Education – add to student teachers. Thus, this article asks: What is the contribution of a research-informed master’s module to ITT? The findings of the research indicate that the master’s module offered opportunities to alter preconceptions and beliefs about teaching and learning; the process of essay writing enhanced critical reflection, which inspired more confidence in the classroom; and the potential theory–practice divide can be viewed as offering opportunities for enhancing self-efficacy. These findings suggest that master’s study has an impact on teachers within their ITT period and beyond it, and have implications for learning processes and content for programmes both in England and internationally.
Evaluation of Sawdust as a Sustainable Dye Source in Ethiopia
Authors: P. Chandrasekaran , Ratnapandian Saminathan
Published: February 2023

Increasing eco-consciousness among consumers is creating an expanding niche market for textiles coloured using natural dyes. Natural dyes are derived from different parts of plants, animals (insects and invertebrates) and minerals. Although plant sources are common, a growing global population makes them compete with food crops. Hence, there is a need to investigate alternate avenues for procuring natural dyes. This research examined the feasibility of utilizing extractions of sawdust, a waste product of the wood furniture industry, as a natural colorant. Sawdust is an inevitable waste generated during the conversion of wood into consumer products such as furniture (tables, chairs, etc.), doors and windows. Sawdust, generated in significant amounts by timber mills, may be used in chipboard manufacture. However, the furniture industry disposes of sawdust as fuel or sometimes as communal waste. In this study, segregated sawdust of the most common woods was collected from Ethiopian furniture houses in Addis Ababa and Bahir Dar. Dyeing was attempted on cotton and wool fabrics using individual aqueous extractions. Different shades were obtained only on wool by simultaneous mordanting with mordants, such as copper sulphate, ferrous sulphate and potassium dichromate, using the exhaust dyeing method. Acceptable fastness to light, perspiration, rubbing and washing, as evaluated according to the relevant ISO standards, was obtained. It may be concluded that sawdust is a viable secondary source of natural dyes for textile coloration in Ethiopia and elsewhere.
Formulation and Characteristics Analysis of Soap with The Addition of Spirulina Platensis
Authors: Hadiyanto H. , Handayani Aniek Sri , Izzah Miftah Aqidatul , Christwardana Marcelinus
Published: February 2023

Cleanliness has become an integral element of daily living. Soap is often used as a cleaning agent. Soap can remove grime and microorganisms that adhere to the skin. Various types of fats or oils are often utilized as soap's primary constituents. The usage of these diverse oils alters the properties of soap, beginning with its hardness, its impact on the skin, and the resultant foam. 3 grams and 5 grams of Spirulina are added to the soap formulation. The pH test, foam height test, and organoleptic test are the test parameters. The findings demonstrated that the pH of each solid soap preparation was nine, which was in agreement with national standard criteria. The foam stability formed was 75% and 25%, and that the soap formulation maintained its color, shape, and odor for a period of ten days during storage. This research concludes that Spirulina platensis can be made into a solid soap formulation. The effects of the addition of Spirulina to solid soap include a light green color, a solid shape or solid texture, and a distinct perfume of essential tea tree oil, as well as the production of quite a bit of foam and a little coarseness.
Mohammed Bin Salman’s Rising to Power. Chances for Transition in Saudi Arabia?
Authors: Ożarowski Rafał
Published: February 2023

The aim of this paper is to present the outline of planned and already implemented social, political and economic changes in the context of gradual transition of power in the Kingdom of Saudi Arabia. The main thesis put in this paper relates to Mohammed bin Salman’s leading project – “Vision 2030” which assumed gradual multi-dimensional transition in Saudi Arabia. Many of changes implemented already, including the limitation of clergy’s activity will not bring about quick social-political transition due to long-lasting and deeply rooted alliance between Saudi ruling clan and radical movement of Wahhabis, that determines conservative regime in the country. Basing on the main thesis Author tries to give the answer to research questions correlated with the thesis and touching the issue of possibility for implementation political, economic changes in Saudi Arabia by Mohammed bin Salman. In the paper following research methods has been applied: historical method, which refers to analysis of historical process of shaping and development Saudi monarchy; documentary analysis - relating to governmental project “Vision 2030” particularly; elements of systemic approach in which system is constituted by political regime of Saudi Arabia; elements of statistical method employed in the context of variable economic or social data and elements of predictive referring to the model of Saudi Arabia’s development under the rule of Mohammed bin Salman.
The Study of the Effects of us Geopolitical Policies on the Divergence of the Islamic World. Case Study: Southwest Asia
Authors: Afzali Rasoul , Seyedi Asl Seyedmohammad
Published: February 2023

The Islamic world is one of the most important regions in the world in terms of geopolitical competition, focusing on the region of Southwest Asia in terms of geo-economic, geo-strategic and geo-culture. Despite the widespread commonalities in the political geography of the Islamic world in structural and functional terms, the interdependence of the region has not been able to move towards convergence, cooperation and interaction. One of the influential variables in the political trends of this region has been the geopolitical policies of the United States of America. The United States has always influenced the political trends of this strategic region based on its goals and interests. The result of researches show that the United States has a significant impact on divergence of Islamic world in terms of geo-culture in promoting the discourse of liberalism, geo-strategy on arms sales and stabilization of military rivalries between world powers, and geo-economics in free market competition and cheap energy resources. The convergence of Islamic world has been against the geopolitical interests of the United States of America.
Japan’s Taiwan Policy in the Xi Jinping Era: Moving Toward Strategic Clarity
Authors: Chen Yu-Hua
Published: February 2023

Like the United States, Japan views its relations with Taiwan through a greater China framework. It uses a similar strategic ambiguity toward Taiwan to navigate its relations with China and Taiwan. However, Japan’s recent strong support for Taiwan to counter China’s pressure on the island seems to suggest that Japan’s Taiwan policy is moving away from its old strategic ambiguity toward a new strategic clarity. Why has Japan started to protect Taiwan proactively and directly in recent years? How to explain the transformation of Japan’s policy regarding Taiwan from strategic ambiguity to strategic clarity? Drawing upon various primary materials, this article approached those questions from a social constructivism lens. It argues that Japan’s new identity is a critical factor in Japan’s strategic transformation of its Taiwan policy. Japan’s new identity has first taken shape due to the growing challenge from China, and second been accelerated and hardened by the caprices of the United States. It is this new identity and its associated normative expectations that have caused Japan’s foreign behaviour to change fundamentally. This article will detail the process in which how Japan steadily changed its state identity over the years after showing that the existing explanations are unable to properly account for the shift of Japan’s policy toward Taiwan. Some policy implications will be offered in the conclusion section.
Scientific Research in Austrian Security Strategies and Research on Security and Defence
Authors: Szewior Krzysztof
Published: February 2023

Official documents of the Austrian government indicate the growing dependence of the economy and society on technical infrastructure, which required continuous research. Austria has developed a national research program to promote its economy, technology and cooperation. It is also intended to support the Austrian defence and civilian economy as a coherent part of the EU’s research, technology and economic structures. This text is based in particular on primary literature, which includes documents of EU institutions, Austrian security and defence strategies, and statements of the Ministry of Defense. This publication attempts to answer the question of how Austria made an effort to integrate security and defence issues with the national research-technology-innovation system (Forschung-Technologie-Innovation, hereinafter FTI), with the specificity of the domestic industry dominated by small and medium-sized enterprises. This paper is based on the analysis of documents and scientific interpretation of key EU and Austrian positions. The research aims to analyze and understand the role of research in the concept of (national) security in Austria and to link it with the EU’s security and defence policy. Research and this publication verify the assumption that the security and strategic autonomy of the EU / Member States require integrated solutions (Europeanization process). Going beyond the soft impact toward hard instruments requires a knowledge-based development and synergies of coherent strategies, technologies and research. The EU saw the need for a structured promotion of research and innovation in the field of security and defence. Austria has been developing such research for several years, mainly at the national level and application. The steps taken by Austria demonstrate the will to operate in wider EU (infra) structures and to benefit from financial instruments while supporting and profiting from socio-economic processes.
Dual-band open-loop monopole (2 × 1) printed MIMO antenna for 4G and 5G applications
Authors: Abdulhameed Abdulghafor A. , Alnahwi Falih M. , Abdullah Abdulkareem S.
Published: February 2023

This paper presents a compact dual-band open-loop monopole MIMO antenna to serve 4G/5G applications. This antenna consists of two printed monopole antennas with very high isolation. Two enhancement techniques are utilized to improve the isolation between ports. Since each technique can provide high isolation of a single band, a combination of λ/4 slot and T-shape techniques are used to achieve high isolation of −19 dB and −35 dB at 2.4 GHz and 3.5 GHz, respectively. The proposed design has high efficiency, a low envelope correlation coefficient, and an acceptable level of realized gain (2.7 dBi and 2.2 dBi) at low and high bands. This design has been fabricated using low-profile printed circuit technology with a compact patch size of 50 × 25 mm2 based on an FR-4 substrate. Moreover, the simulation and measurement results are in good agreement.
A novel non-iterative algorithm for the joint design of transceiver beamforming and surface reflection in an IRS-enhanced MIMO system
Authors: Asgari Tabatabaee Seyyed Mohammad Javad , Samsami Khodadad Farid
Published: February 2023

Intelligent reflecting surface (IRS) is an emerging and low-cost revolutionary technology that can be deployed in future communication systems to enhance data transmission performance. An IRS comprises a lot of small, passive, and low-cost elements that can smartly reflect the incident signal from the transmitter to the receiver. In this paper, an IRS-enhanced multiple-input multiple-output (MIMO) downlink network is considered, in which a cell-edge user receives the data signal from a base station (BS). In this network, the direct path between the BS and the user is blocked by an obstacle, and the user receives only the tunable reflected signal from the IRS. To achieve spatial diversity, beamforming is applied to the antennas at the BS and the user. The goal is to jointly design the transceiver beamforming vectors and the IRS reflection coefficients so that the signal-to-noise ratio (SNR) of the user is maximized. Since the IRS elements are passive, the amplitude of the IRS reflection coefficients must be equal to or smaller than one. The constrained SNR optimization problem is non-convex. We propose a three-step procedure to obtain an effective sub-optimal solution for this problem. Accordingly, an innovative non-iterative algorithm is proposed to design the problem parameters. Simulation results show that the IRS-enhanced MIMO downlink system, in which the proposed non-iterative algorithm is used to develop the network parameters, outperforms the conventional network without IRS in terms of bit error rate (BER).
A New Perspective on Humanity in the Cosmic Future: A Critical Reflection on Some Transhumanist Visions
Authors: Farbák Martin , Plašienková Zlatica
Published: February 2023

The authors of this article critically consider selected transhumanist views of new perspectives on humanity in the cosmic future. Their focus is on philosophical and ethical thinking about the futuristic concepts of Cyborgs and Cosmic Beings promoted by Ted Chu. They weight up the possible negative consequences of radical human enhancement and analyse the utilitarian roots of the conceptions discussed. The theory of planetary and cosmic personality appears to be a safer alternative to radical human enhancement but they also pinpoint drawbacks to the theory. The authors conclude that a more conservative and authentic approach to human enhancement is found in the truly human enhancement proposed by Nicholas Agar and consider life-centred ethics an appropriate ethical standpoint in the search for humans’ place in the cosmic future.
Influence of surfactant concentration on structural properties and corrosion behaviour of electrodeposited Ni–SiO2 nanocomposite coatings
Authors: Guerguer Louiza , Hamdi Ahmed , Ziouche Aicha , Benbertal Djamel , Belalem Mohammed Abdelkader , Benmoussat Abderrahim
Published: February 2023

In this study, Ni–SiO2 nanocomposite coatings were deposited on the surface of X70 steel by performing direct current electrodeposition. The effect of different concentrations of cetyltrimethylammonium bromide surfactant (0.3, 0.5, 1, and 2 g L−1) on particle distribution and corrosion behaviour of the coatings was analysed. The structural properties of the obtained coatings were evaluated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis, X-ray diffraction, and atomic force microscopy. The corrosion behaviour of the coatings was tested by potentiodynamic polarisation and electrochemical impedance spectroscopy. The results showed that the electrodeposited coatings obtained from the electroplating bath with 1 g L−1 of surfactant modified the surface morphology of the Ni–SiO2 nanocomposite coating and presented a finer and more uniform microstructure. The results of the phase structure analysis showed that the addition of the surfactant in the electrodeposition process changed the preferred orientations for the coatings from (111) to (220) and (200) planes. The anti-corrosion performance of the resulting coating produced in the presence of 1 g L−1 of surfactant was significantly higher than the anti-corrosion performance of the other coatings and showed a lower corrosion rate.
Synthesis of nickel oxide nanoparticles as an agent for antibacterial and wastewater remediation applications by calcination
Authors: Şenocak Ayşegül , İmamoğlu Rızvan , Yılmaz Sefa
Published: February 2023

In this paper, a nickel complex with the general formula [Ni(HST)(OAc)] (HST: 1-salicylaldehydethiosemicarbazone, OAc: acetate) was subjected to thermal decomposition to produce nanoparticles at three different temperatures. The semiconductor nanoparticles have a particle size of 22.18 nm and a band gap of 2.68 eV. Furthermore, it was observed that the nanoparticles exhibiting a zeta-potential value of −26.1 are stable in colloidal media. The produced nanoparticles have the potential to be used as wastewater treatment agents under optimized conditions, as evidenced by the photocatalytic activity on methylene blue degradation with a 69.30% decomposition. Although all the synthesized compounds exhibit high antibacterial activity with low minimal inhibitory concentration values, the nanoparticles obtained by calcination at 400 °C had the highest activity, which is consistent with the literature.
Deep learning for content-based image retrieval in FHE algorithms
Authors: Abdullah Sura Mahmood , Jaber Mustafa Musa
Published: February 2023

Content-based image retrieval (CBIR) is a technique used to retrieve image from an image database. However, the CBIR process suffers from less accuracy to retrieve many images from an extensive image database and prove the privacy of images. The aim of this article is to address the issues of accuracy utilizing deep learning techniques such as the CNN method. Also, it provides the necessary privacy for images using fully homomorphic encryption methods by Cheon–Kim–Kim–Song (CKKS). The system has been proposed, namely RCNN_CKKS, which includes two parts. The first part (offline processing) extracts automated high-level features based on a flatting layer in a convolutional neural network (CNN) and then stores these features in a new dataset. In the second part (online processing), the client sends the encrypted image to the server, which depends on the CNN model trained to extract features of the sent image. Next, the extracted features are compared with the stored features using a Hamming distance method to retrieve all similar images. Finally, the server encrypts all retrieved images and sends them to the client. Deep-learning results on plain images were 97.87% for classification and 98.94% for retriever images. At the same time, the NIST test was used to check the security of CKKS when applied to Canadian Institute for Advanced Research (CIFAR-10) dataset. Through these results, researchers conclude that deep learning is an effective method for image retrieval and that a CKKS method is appropriate for image privacy protection.
Sustainable development of simulation setups and addons for OpenFOAM for nuclear reactor safety research
Authors: Lehnigk Ronald , Bruschewski Martin , Huste Tobias , Lucas Dirk , Rehm Markus , Schlegel Fabian
Published: February 2023

Open-source environments such as the Computational Fluid Dynamics software OpenFOAM are very appealing for research groups since they allow for an efficient prototyping of new models or concepts. However, for downstream developments to be sustainable, i.e. reproducible and reusable in the long term, a significant amount of maintenance work must be accounted for. To allow for growth and extensibility, the maintenance work should be underpinned by a high degree of automation for repetitive tasks such as build tests, code deployment and validation runs, in order to keep the focus on scientific work. Here, an information technology environment is presented that aids the centralized maintenance of addon code and setup files with relation to reactor coolant system safety research. It fosters collaborative developments and review processes. State-of-the-art tools for managing software developments are adapted to meet the requirements of OpenFOAM. A flexible approach for upgrading the underlying installation is proposed, based on snapshots of the OpenFOAM development line rather than yearly version releases, to make new functionality available when needed by associated research projects. The process of upgrading within so-called sprint cycles is accompanied by several checks to ensure compatibility of downstream code and simulation setups. Furthermore, the foundation for building a validation data base from contributed simulation setups is laid, creating a basis for continuous quality assurance.
Topological phases and non-Hermitian topology in photonic artificial microstructures
Authors: Liu Hui , Lai Pengtao , Wang Haonan , Cheng Hua , Tian Jianguo , Chen Shuqi
Published: February 2023

In the past few decades, the discovery of topological matter states has ushered in a new era in topological physics, providing a robust framework for strategically controlling the transport of particles or waves. Topological photonics, in particular, has sparked considerable research due to its ability to construct and manipulate photonic topological states via photonic artificial microstructures. Although the concept of topology originates from condensed matter, topological photonics has given rise to new fundamental ideas and a range of potential applications that may lead to revolutionary technologies. Here, we review recent developments in topological photonics, with a focus on the realization and application of several emerging research areas in photonic artificial microstructures. We highlight the research trend, spanning from the photonic counterpart of topological insulator phases, through topological semimetal phases, to other emerging non-Hermitian topologies.