bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibrational strong coupling between Tamm phonon polaritons and organic molecules
Authors: Xu Chenran , Cai Han , Wang Da-Wei
Published: March 2021

Phonon polaritons (PhPs) have a long lifetime and high confinement of light fields compared with their plasmonic counterparts in the mid-infrared range. Thus, PhPs are promising candidates for realizing vibrational strong coupling (VSC) with molecules. However, VSCs of PhPs in nanoresonators and thin films require the near-field technique and are limited to the transverse magnetic mode. Here we propose a new configuration based on the Tamm structure, which supports PhPs excited by the free-space incident light in both transverse-electric and transverse-magnetic modes. The VSC of a 300 nm thick molecular layer can be achieved with

21

c
m

−
1

Rabi splitting, according to the numerically obtained angle resolved reflectivity spectra with the transfer matrix method. Our findings provide a promising platform for applications in free-space sensing of vibrational modes and control of chemical reactions in compact devices.
Daylight window based on the nano-disorder inspired by Morpho butterflies’ coloration
Authors: Saito Akira , Yamashita Kazuma , Shibuya Takuto , Kuwahara Yuji
Published: March 2021

Some species of Morpho butterflies reflect interfered brilliant blue, which is contradictory to the interference effect due to low angular dependence. This coloration is typically attributed to the disordered nanostructure of the species scales. Applying this reflective principle into light transmission, we discover a new daylight window with high transmittance, wide angular spread, and low color dispersion. The effectiveness of this window was verified through numerical simulations. The optical conditions were investigated by changing the structural parameters, and the required conditions were clarified. This concept realizes an ideal window based on a new principle.
Tunable electromagnetically induced transparency metamaterial based on solid-state plasma: from a narrow band to a broad one
Authors: Chen Quanfang , Li Fenying , Zhang Dan , Zhang Haifeng
Published: March 2021

Based on solid-state plasma (SSP), an electromagnetically induced transparent (EIT) metamaterial is proposed. Simulations illustrate that the given metamaterial has the characteristics of adjustment, polarization insensitivity, and low dissipation. Because SSP can be coordinated in state I, the ideal transmittance frequency band can cover 8.0335–9.02531 GHz (a narrow band). If the regulatory status is switched to state II, that frequency region will alter to 9.7982–12.9275 GHz (a broad band). As SSP can be switched back and forth between states I and II under actual demand, the tailored EIT metamaterial can be achieved. The maximum group delays of state I and state II are 0.9437 ns and 0.5546 ns, respectively, and the maximum group refractive indices are 526.60 and 300.45, respectively, which conforms to its slow light characteristic. Regardless of how the polarization angle changes, the two transmission valleys of state I are at 7.9172 GHz and 10.4446 GHz, and the transmission peak is situated at 8.2091 GHz, and those values of state II are 9.3777 GHz, 13.9600 GHz, and 10.1920 GHz, respectively, which proves that the obtained EIT is polarization independent and also has a low dissipation factor. Such an EIT metamaterial has excellent properties in sensing, communication, slow light, and other fields.
Transmitter and receiver impairment monitoring using adaptive multi-layer linear and widely linear filter coefficients controlled by stochastic gradient descent
Authors: Arikawa Manabu , Hayashi Kazunori
Published: March 2021

We propose a monitoring method for individual impairments in a transmitter (Tx) and receiver (Rx) by using filter coefficients of multi-layer strictly linear (SL) and widely linear (WL) filters to compensate for relevant impairments where the filter coefficients are adaptively controlled by stochastic gradient descent with back propagation from the last layer outputs. Considering the order of impairments occurring in a Tx or Rx of coherent optical transmission systems and their non-commutativity, we derive a model relating in-phase (I) and quadrature (Q) skew, IQ gain imbalance, and IQ phase deviation in a Tx or Rx to the WL filter responses in our multi-layer filter architecture. We evaluated the proposed method through simulations using polarization-division multiplexed (PDM)-quadrature phase shift keying and a transmission experiment of 32-Gbaud PDM 64-quadrature amplitude modulation over a 100-km single-mode fiber span. The results indicate that both Tx and Rx impairments could be individually monitored by using the filter coefficients of adaptively controlled multi-layer SL and WL filters precisely and simultaneously, decoupled by chromatic dispersion and frequency offset, even when multiple impairments existed.
Highly efficient polarization-entangled photon-pair generation in lithium niobate waveguides based on bound states in continuum
Authors: Chen G. Y. , Li Z. X. , Chen Y. H. , Zhang X. D.
Published: March 2021

Integrated optics provides a platform for the experimental implementation of highly complex and compact circuits for practical applications as well as for advances in the fundamental science of quantum optics. The lithium niobate (LN) waveguide is an important candidate for the construction of integrated optical circuits. Based on the bound state in the continuum (BIC) in a LN waveguide, we propose an efficient way to produce polarization-entangled photon pairs. The implementation of this method is simple and does not require the polarization process needed for periodically poled LN. The generation rate of the entangled photon pairs increases linearly with the length of the waveguide. For visible light, the generation efficiency can be improved by more than five orders of magnitude with waveguides having the length of only a few millimeters, compared with the corresponding case without BICs. The phenomena can appear in a very wide spectrum range from the visible to THz regions. This study is of great significance for the development of active integrated quantum chips in various wavelength ranges.
Broadband and compact polarization beam splitter in LNOI hetero-anisotropic metamaterials
Authors: Deng Chunyu , Lu Mengjia , Sun Yu , Huang Lei , Wang Dongyu , Hu Guohua , Zhang Ruohu , Yun Binfeng , Cui Yiping
Published: March 2021

In this paper, theoretical modeling and numerical simulations of a high-performance polarization beam splitter (PBS) based on hetero-anisotropic metamaterials are proposed on the lithium-niobate-on-insulator (LNOI) platform. The hetero-anisotropic metamaterials constructed by sub-wavelength gratings (SWGs) can be regarded as effective anisotropy medium, which exhibits strong birefringence without breaking the geometrical symmetry, contributing to the formation of PBS. Rather than the principle of PBS based on beat-length difference of transverse electric (TE) polarization and transverse magnetic (TM) polarization, the device can realize polarization beam splitting in single beat length, and the footprint of the proposed PBS can be reduced to 8 µm × 160 µm (with S-bend). The simulation results show that the bandwidth is 185 nm (1450∼1634 nm) for TE polarization while the bandwidth is 85 nm (1490∼1575 nm) for TM polarization when the polarization extinction ratio is >20 dB. Furthermore, the insertion loss is less than 1 dB in the range of 1450 to 1650 nm, for both TE and TM polarization. Additionally, the proposed device proves strong robustness of the fabrication tolerance.
Nonlinear modulation on optical trapping in a plasmonic bowtie structure
Authors: Zhang Wenjun , Zhang Yuquan , Zhang Shuoshuo , Wang Yulong , Yang Wu , Min Changjun , Yuan Xiaocong
Published: March 2021

Surface plasmon optical tweezers based on micro- and nano-structures are capable of capturing particles in a very small spatial scale and have been widely used in many front research fields. In general, distribution of optical forces and potential wells exerted on the particles can be modulated by controlling the geometric parameters of the structures. However, these fabricated structures are irreversible once processed, which greatly limits its application in dynamic manipulation. The plasmonic field in these structures can be enhanced with orders of magnitude compared to the excitation light, offering a possibility to stimulate nonlinear responses as a new degree of freedom for dynamic modulation. Here, we theoretically demonstrate that the optical force and potential well can be modulated on account of the nonlinear Kerr effect of a gold bowtie structure under a pulsed laser with high peak power. The results verify that the trapping states, including the position, width, and depth of the potential well, can be dynamically modulated by changing intensity of the incident laser. It provides an effective approach for stable trapping and dynamic controlling of particles on nanostructure-based plasmonic trapping platforms and thus has great application potential in many fields, such as enhanced Raman detection, super-resolution imaging, and optical sensing.
Inverse design of unparametrized nanostructures by generating images from spectra
Authors: Malkiel Itzik , Mrejen Michael , Wolf Lior , Suchowski Haim
Published: March 2021

Recently, there has been an increasing number of studies applying machine learning techniques for the design of nanostructures. Most of these studies train a deep neural network (DNN) to approximate the highly nonlinear function of the underlying physical mapping between spectra and nanostructures. At the end of training, the DNN allows an on-demand design of nanostructures, i.e., the model can infer nanostructure geometries for desired spectra. While these approaches have presented a new paradigm, they are limited in the complexity of the structures proposed, often bound to parametric geometries. Here we introduce spectra2pix, which is a DNN trained to generate 2D images of the target nanostructures. By predicting an image, our model architecture is not limited to a closed set of nanostructure shapes, and can be trained for the design of a much wider space of geometries. We show, for the first time, to the best of our knowledge, a successful generalization ability, by designing completely unseen shapes of geometries. We attribute the successful generalization to the ability of a pixel-wise architecture to learn local properties of the meta-material, therefore mimicking faithfully the underlying physical process. Importantly, beyond synthetical data, we show our model generalization capability on real experimental data.
Compressive imaging for defending deep neural networks from adversarial attacks
Authors: Kravets Vladislav , Javidi Bahram , Stern Adrian
Published: March 2021

Despite their outstanding performance, convolutional deep neural networks (DNNs) are vulnerable to small adversarial perturbations. In this Letter, we introduce a novel approach to thwart adversarial attacks. We propose to employ compressive sensing (CS) to defend DNNs from adversarial attacks, and at the same time to encode the image, thus preventing counterattacks. We present computer simulations and optical experimental results of object classification in adversarial images captured with a CS single pixel camera.
Optical characterization of Y3Al5O12 and Lu3Al5O12 single crystals
Authors: Hrabovský J. , Kučera M. , Paloušová L. , Bi L. , Veis M.
Published: March 2021

In this work spectrally dependent optical parameters of nominally pure single crystals of yttrium aluminum garnet (YAG) and lutetium aluminum garnet (LuAG) were studied using spectroscopy ellipsometry together with transmittance measurements in a broad spectral range from 0.73 to 6.42 eV (193–1700 nm). Obtained data in terms of complex refractive index and reflectivity represent an extension of previous studies towards the ultraviolet spectral region and provide a background for the design of a variety of optical applications such as laser host matrix systems, doped luminescence materials, optical imaging devices for semiconductor immersion lithography, construction of scintillators and other devices operating in the ultraviolet spectral region. A complete database of obtained optical parameters (real and imaginary parts of complex refractive index) in the whole spectral range is included in the supplementary part.
Mid-infrared interference coatings with excess optical loss below 10  ppm
Authors: Winkler G. , Perner L. W. , Truong G.-W. , Zhao G. , Bachmann D. , Mayer A. S. , Fellinger J. , Follman D. , Heu P. , Deutsch C. , Bailey D. M. , Peelaers H. , Puchegger S. , Fleisher A. J. , Cole G. D. , Heckl O. H.
Published: March 2021

Low excess optical loss, combined absorption and scatter loss, is a key performance metric for any high-reflectance coating technology and is currently one of the main limiting factors for the application of optical resonators in the mid-infrared spectral region. Here we present high-reflectivity substrate-transferred single-crystal GaAs/AlGaAs interference coatings at a center wavelength of 4.54 µm with record-low excess optical loss below 10 parts per million. These high-performance mirrors are realized via a novel microfabrication process that differs significantly from the production of amorphous multilayers generated via physical vapor deposition processes. This new process enables reduced scatter loss due to the low surface and interfacial roughness, while low background doping in epitaxial growth ensures strongly reduced absorption. We report on a suite of optical measurements, including cavity ring-down, transmittance spectroscopy, and direct absorption tests to reveal the optical losses for a set of prototype mirrors. In the course of these measurements, we observe a unique polarization-orientation-dependent loss mechanism which we attribute to elastic anisotropy of these strained epitaxial multilayers. A future increase in layer count and a corresponding reduction of transmittance will enable optical resonators with a finesse in excess of 100,000 in the mid-infrared spectral region, allowing for advances in high-resolution spectroscopy, narrow-linewidth laser stabilization, and ultrasensitive measurements of various light–matter interactions.
Lamellar hafnium ditelluride as an ultrasensitive surface-enhanced Raman scattering platform for label-free detection of uric acid
Authors: Li Yang , Chen Haolin , Guo Yanxian , Wang Kangkang , Zhang Yue , Lan Peilin , Guo Jinhao , Zhang Wen , Zhong Huiqing , Guo Zhouyi , Zhuang Zhengfei , Liu Zhiming
Published: March 2021

The development of two-dimensional (2D) transition metal dichalcogenides has been in a rapid growth phase for the utilization in surface-enhanced Raman scattering (SERS) analysis. Here, we report a promising 2D transition metal tellurides (TMTs) material, hafnium ditelluride (

HfTe

2

), as an ultrasensitive platform for Raman identification of trace molecules, which demonstrates extraordinary SERS activity in sensitivity, uniformity, and reproducibility. The highest Raman enhancement factor of

2.32
×

10

6

is attained for a rhodamine 6G molecule through the highly efficient charge transfer process at the interface between the

HfTe

2

layered structure and the adsorbed molecules. At the same time, we provide an effective route for large-scale preparation of SERS substrates in practical applications via a facile stripping strategy. Further application of the nanosheets for reliable, rapid, and label-free SERS fingerprint analysis of uric acid molecules, one of the biomarkers associated with gout disease, is performed, which indicates arresting SERS signals with the limits of detection as low as 0.1 mmol/L. The study based on this type of 2D SERS substrate not only reveals the feasibility of applying TMTs to SERS analysis, but also paves the way for nanodiagnostics, especially early marker detection.
Healthcare without borders: A cross-sectional study of immigrant and nonimmigrant children admitted to a large public sector hospital in the Gauteng Province of South Africa
Authors: Janse van Rensburg Gerhard H. , Feucht Ute Dagmar , Makin Jennifer , le Clus Nanya , Avenant Theunis
Published: March 2021

Background

Human migration is a worldwide phenomenon that receives considerable attention from the media and healthcare authorities alike. A significant proportion of children seen at public sector health facilities in South Africa (SA) are immigrants, and gaps have previously been noted in their healthcare provision.

The objective of the study was to describe the characteristics and differences between the immigrant and SA children admitted to Kalafong Provincial Tertiary Hospital (KPTH), a large public sector hospital in the urban Gauteng Province of SA.

Methods and findings

A cross-sectional study was conducted over a 4-month period during 2016 to 2017. Information was obtained through a structured questionnaire and health record review. The enrolled study participants included 508 children divided into 2 groups, namely 271 general paediatric patients and 237 neonates. Twenty-five percent of children in the neonatal group and 22.5% in the general paediatric group were immigrants. The parents/caregivers of the immigrant group had a lower educational level (p < 0.0001 neonatal and paediatric), lower income (neonatal p < 0.001; paediatric p = 0.024), difficulty communicating in English (p < 0.001 neonatal and paediatric), and were more likely residing in informal settlements (neonatal p = 0.001; paediatric p = 0.007) compared to the SA group. In the neonatal group, there was no difference in the number of antenatal care (ANC) visits, type of delivery, gestational age, and birth weight. In the general paediatric group, there was no difference in immunisation and vitamin A supplementation coverage, but when comparing growth, the immigrant group had more malnutrition compared to the SA group (p = 0.029 for wasting). There was no difference in the prevalence of maternal human immunodeficiency virus (HIV) infection, with equally good prevention of mother-to-child transmission (PMTCT) coverage. There was also no difference in reported difficulties by immigrants in terms of access to healthcare (neonatal p = 0.379; paediatric p = 0.246), although a large proportion (10%) of the neonates of immigrant mothers were born outside a medical facility.

Conclusions

Although there were health-related differences between immigrant and SA children accessing in-hospital care, these were fewer than expected. Differences were found in parental educational level and socioeconomic factors, but these did not significantly affect ANC attendance, delivery outcomes, immunisation coverage, HIV prevalence, or PMTCT coverage. The immigrant population should be viewed as a high-risk group, with potential problems including suboptimal child growth. Health workers should advocate for all children in the community they are serving and promote tolerance, respect, and equal healthcare access.
Learning can be detrimental for a parasitic wasp
Authors: Bertoldi Valeria , Rondoni Gabriele , Peri Ezio , Conti Eric , Brodeur Jacques
Published: March 2021

Animals have evolved the capacity to learn, and the conventional view is that learning allows individuals to improve foraging decisions. The parasitoid Telenomus podisi has been shown to parasitize eggs of the exotic stink bug Halyomorpha halys at the same rate as eggs of its coevolved host, Podisus maculiventris, but the parasitoid cannot complete its development in the exotic species. We hypothesized that T. podisi learns to exploit cues from this non-coevolved species, thereby increasing unsuccessful parasitism rates. We conducted bioassays to compare the responses of naïve vs. experienced parasitoids on chemical footprints left by one of the two host species. Both naïve and experienced females showed a higher response to footprints of P. maculiventris than of H. halys. Furthermore, parasitoids that gained an experience on H. halys significantly increased their residence time within the arena and the frequency of re-encounter with the area contaminated by chemical cues. Hence, our study describes detrimental learning where a parasitoid learns to associate chemical cues from an unsuitable host, potentially re-enforcing a reproductive cul-de-sac (evolutionary trap). Maladaptive learning in the T. podisi—H. halys association could have consequences for population dynamics of sympatric native and exotic host species.
Differential privacy fuzzy C-means clustering algorithm based on gaussian kernel function
Authors: Zhang Yaling , Han Jin
Published: March 2021

Fuzzy C-means clustering algorithm is one of the typical clustering algorithms in data mining applications. However, due to the sensitive information in the dataset, there is a risk of user privacy being leaked during the clustering process. The fuzzy C-means clustering of differential privacy protection can protect the user’s individual privacy while mining data rules, however, the decline in availability caused by data disturbances is a common problem of these algorithms. Aiming at the problem that the algorithm accuracy is reduced by randomly initializing the membership matrix of fuzzy C-means, in this paper, the maximum distance method is firstly used to determine the initial center point. Then, the gaussian value of the cluster center point is used to calculate the privacy budget allocation ratio. Additionally, Laplace noise is added to complete differential privacy protection. The experimental results demonstrate that the clustering accuracy and effectiveness of the proposed algorithm are higher than baselines under the same privacy protection intensity.
A model-based cost-utility analysis of multi-professional simulation training in obstetric emergencies
Authors: Yau Christopher Wai Hung , Lenguerrand Erik , Morris Steve , Draycott Tim , Pizzo Elena
Published: March 2021

Objective

To determine the cost-utility of a multi-professional simulation training programme for obstetric emergencies–Practical Obstetric Multi-Professional Training (PROMPT)–with a particular focus on its impact on permanent obstetric brachial plexus injuries (OBPIs).

Design

A model-based cost-utility analysis.

Setting

Maternity units in England.

Population

Simulated cohorts of individuals affected by permanent OBPIs.

Methods

A decision tree model was developed to estimate the cost-utility of adopting annual, PROMPT training (scenario 1a) or standalone shoulder dystocia training (scenario 1b) in all maternity units in England compared to current practice, where only a proportion of English units use the training programme (scenario 2). The time horizon was 30 years and the analysis was conducted from an English National Health Service (NHS) and Personal Social Services perspective. A probabilistic sensitivity analysis was performed to account for uncertainties in the model parameters.

Main outcome measures

Outcomes for the entire simulated period included the following: total costs for PROMPT or shoulder dystocia training (including costs of OBPIs), number of OBPIs averted, number of affected adult/parental/dyadic quality adjusted life years (QALYs) gained and the incremental cost per QALY gained.

Results

Nationwide PROMPT or shoulder dystocia training conferred significant savings (in excess of £1 billion ($1.5 billion)) compared to current practice, resulting in cost-savings of at least £1 million ($1.5 million) per any type of QALY gained. The probabilistic sensitivity analysis demonstrated similar findings.

Conclusion

In this model, national implementation of multi-professional simulation training for obstetric emergencies (or standalone shoulder dystocia training) in England appeared to both be cost-saving when evaluating their impact on permanent OBPIs.
The association of pregnancy control, emotions, and beliefs with pregnancy desires: A new perspective on pregnancy intentions
Authors: Manze Meredith G. , Romero Diana R. , De Prabal , Hartnett Josette , Roberts Lynn
Published: March 2021

Context

Standard pregnancy intentions measures do not always align with how people approach pregnancy. Studies that have investigated beyond a binary framework found that those with “ambivalent” feelings towards pregnancy are less likely to use contraception consistently, but the reasons for this are unclear. We sought to gain a nuanced understanding of pregnancy desires, and how perceptions about pregnancy are associated with contraceptive use.

Methods

We used non-probability quota sampling based on sex, age, and geographic region for a web-based survey of heterosexual men and women, aged 21–44 years, who could become pregnant/impregnate and were not currently pregnant (n = 1,477; 51% female). The survey was created using unique items informed by recent literature. Bivariate and multivariable analyses explored relationships between various perceptions about pregnancy with pregnancy desires categorized as: wanting a pregnancy, not wanting a pregnancy, and not trying but would be okay with a pregnancy. We conducted a sub-group analysis of those who were not trying but would be okay with a pregnancy (n = 460), using descriptive statistics to examine how consistent contraceptive use was associated with emotions and beliefs about avoiding pregnancy.

Results

After adjustment, those who felt that pregnancy may not always be avoidable, but instead determined by fate/higher power, or a natural process that happens when it is meant to, were significantly more likely (aOR: 1.83, 95% CI: 1.05–3.36; aOR: 2.21, 95% CI: 1.29–3.76, respectively) to report not trying but being okay with pregnancy, whereas those with negative feelings about a pregnancy were less likely to feel okay about a pregnancy (aOR: 0.11, 95% CI: 0.08–0.15), versus not wanting a pregnancy. In the sub-group analysis, those who felt pregnancy was determined by fate/higher power or a natural process were more likely to report not using contraception consistently (70%, 68%, respectively).

Conclusions

Those who state they are not trying but would be okay with pregnancy may not use contraception consistently because of beliefs that pregnancy is predetermined. Our findings support less categorical and more multidimensional approaches to measuring fertility intentions, with important implications for reproductive health service provision.
Becoming the temporary surgeon: A grounded theory examination of anaesthetists performing emergency front of neck access in inter-disciplinary simulation-based training
Authors: Silverio Sergio A. , Wallace Hilary , Gauntlett William , Berwick Richard , Mercer Simon , Morton Ben , Rogers Simon N. , Sandars John E. , Groom Peter , Brown Jeremy M.
Published: March 2021

The time-critical ‘can’t intubate, can’t oxygenate’ [CICO] emergency post-induction of anaesthesia is rare, but one which, should it occur, requires Anaesthetists to perform rapid emergency front of neck access [FONA] to the trachea, restoring oxygenation, and preventing death or brain hypoxia. The UK Difficult Airway Society [DAS] has directed all Anaesthetists to be trained with surgical cricothyroidotomy [SCT] as the primary emergency FONA method, sometimes referred to as ‘Cric’ as a shorthand. We present a longitudinal analysis using a classical approach to Grounded Theory methodology of ten Specialist Trainee Anaesthetists’ data during a 6-month training programme delivered jointly by Anaesthetists and Surgeons. We identified with a critical realist ontology and an objectivist epistemology meaning data interpretation was driven by participants’ narratives and accepted as true accounts of their experience. Our theory comprises three themes: ‘Identity as an Anaesthetist’; ‘The Role of a Temporary Surgeon’; and ‘Training to Reconcile Identities’, whereby training facilitated the psychological transition from a ‘bloodless Doctor’ (Anaesthetist) to becoming a ‘temporary Surgeon’. The training programme enabled Specialist Trainees to move between the role of control and responsibility (Identity as an Anaesthetist), through self-described ‘failure’ and into a role of uncertainty about one’s own confidence and competence (The Role of a Temporary Surgeon), and then return to the Anaesthetist’s role once the airway had been established. Understanding the complexity of an intervention and providing a better insight into the training needs of Anaesthetic trainees, via a Grounded Theory approach, allows us to evaluate training programmes against the recognised technical and non-technical needs of those being trained.
Correlation between choroidal structure and smoking in eyes with central serous chorioretinopathy
Authors: Okawa Kazuyoshi , Inoue Tatsuya , Asaoka Ryo , Azuma Keiko , Obata Ryo , Arasaki Rei , Ikeda Shouko , Ito Arisa , Maruyama-Inoue Maiko , Yanagi Yasuo , Kadonosono Kazuaki
Published: March 2021

Purpose

A smoking habit can cause various health problems encompassing retinal diseases including central serous chorioretinopathy (CSC). The aim of the current study was to investigate the effect of smoking on the choroidal structure in patients with CSC.

Methods

The choroidal vascular index (CVI) was calculated using the binarized OCT images. Baseline parameters (age, refractive error [SE], subfoveal choroidal thickness [SFCT] and CVI) were compared between smokers and non-smokers using Wilcoxon rank sum test. Moreover, the associations between SFCT and the baseline parameters were analyzed using a multivariate linear regression followed by the AICc model selection.

Results

Among 75 CSC patients, 45 patients were smokers and 30 patients were non-smokers. No significant differences in age and SE were seen between the smoking group and the non-smoking group. A significant difference in the SFCT was seen between two groups (382.0 ± 68.2 μm in the smoking group vs. 339.3 ± 52.3 μm in the non-smoking group,p= 0.0038), while no significant difference was observed in the CVI (p= 0.32). The optimal model for SFCT included the variables of age, SE and past history of smoking among the baseline parameters. Additionally, increased pack years was associated with increased SFCT.

Conclusion

Cigarette smoking was associated with an increased SFCT in patients with CSC. Thicker choroid in smoking CSC patients may be an important modulator of the disease.
Magnitude of asymptomatic COVID-19 cases throughout the course of infection: A systematic review and meta-analysis
Authors: Alene Muluneh , Yismaw Leltework , Assemie Moges Agazhe , Ketema Daniel Bekele , Mengist Belayneh , Kassie Bekalu , Birhan Tilahun Yemanu
Published: March 2021

Background

Asymptomatic SARS-CoV-2 infections are responsible for potentially significant transmission of COVID-19. Worldwide, a number of studies were conducted to estimate the magnitude of asymptomatic COVID-19 cases. However, there is a need for more robust and well-designed studies to have a relevant public health intervention. Synthesis of the available studies significantly strengthens the quality of evidences for public health practice. Thus, this systematic review and meta-analysis aimed to determine the overall magnitude of asymptomatic COVID-19 cases throughout the course of infection using available evidences.

Methods

We followed the PRISMA checklist to present this study. Two experienced review authors (MA and DBK) were systematically searched international electronic databases for studies. We performed meta-analysis using R statistical software. The overall weighted proportion of asymptomatic COVID-19 cases throughout the course infection was computed. The pooled estimates with 95% confidence intervals were presented using forest plot. Egger’s tests were used to assess publication bias, and primary estimates were pooled using a random effects model. Furthermore, a sensitivity analysis was conducted to assure the robustness of the result.

Results

A total of 28 studies that satisfied the eligibility criteria were included in this systematic review and meta-analysis. Consequently, in the meta-analysis, a total of 6,071 COVID-19 cases were included. The proportion of asymptomatic infections among the included studies ranged from 1.4% to 78.3%. The findings of this meta-analysis showed that the weighted pooled proportion of asymptomatic COVID-19 cases throughout the course of infection was 25% (95%CI: 16–38). The leave-one out result also revealed that the weighted pooled average of asymptomatic SARS-CoV-2 infection was between 28% and 31.4%.

Conclusions

In conclusion, one-fourth of SARS-CoV-2 infections are remained asymptomatic throughout the course infection. Scale-up of testing, which targeting high risk populations is recommended to tackle the pandemic.
Moist wound dressing and its application in distant skin flap in cats
Authors: Erwin Erwin , Etriwati Etriwati , Zamzami Rumi Sahara , Hosea Cindy Trie Permatasari
Published: March 2021

Background and Aim: Wound healing is a dynamic and complex process that requires an appropriate environment to promote healing process. The healing of distant flaps in cats is determined by vascularization, nutrient sufficiency for the cells, and stability of skin flaps. This study aims to evaluate the healing of distant flaps treated with moist wound dressing through subjective and objective observation in five cats with wounds in the forelimb and hindlimb area to determine the time to cut the skin flaps from the donor site.

Materials and Methods: In this study, five Indonesian local cats with wounds of various sizes in the limb were brought to the Veterinary Teaching Hospital. The sterile wound treatment included the administration of anesthesia, wound debridement, and distant flap closure in the thoracic and abdominal area. The distant flap and time to cut the skin flaps from the donor site were evaluated through subjective and objective examinations.

Results: The subjective observation on the color of the distant skin flaps showed redness and response to pain on day 3 after surgery, whereas the objective observation, which was based on drug absorption capability and drug effect showed good results. On day 7 after surgery, the skin flaps from the donor site were cut and showed good progress.

Conclusion: Overall, moist dressing helps in stabilizing the distant flap, allowing the distant flaps from the donor site to be cut on day 7 after surgery.
Intézményi és egyéni hasznosságok a hallgatói identitás tükrében
Authors: Mihály Nikolett
Published: March 2021

A szerző tanulmányában Akerlof és Kranton (2002) identitásmodelljét és egy ahhoz kötődő hazai kutatást mutat be. Igazolja, hogy pozitív kapcsolat mutatható ki az egyetem értékeivel való azonosulás, az egyéni hasznosság és az intézmény lehetséges hosszú távú hasznosságai között. Akerlof és Kranton (2005) az identitás és hasznosság hasonló összefüggéseit vállalati szinten is modellezte. A szerzők rámutatnak, hogy egy szervezet működését és eredményességét (hasznosságát) meghatározza, hogy a dolgozók mennyire képesek azonosulni a szervezeti értékekkel, annak küldetésével. E kapcsolat vizsgálata a vállalati eredményesség szempontjából is új lehetőségeket nyújt.
The Design Concept of Rotary Tray Dryer Machine to Dry Gepuk Beef Patties
Authors: Hendrawan Iyus , Haifan Mohamad , Nurani Darti
Published: March 2021

Gepuk is a typical West Java Sundanese food made from cattle beef, tastes a little sweet and savory. Before being served, usually gepuk is fried first, so the effect of frying process can cause health problems due to the repeated use of cooking oil. This study aims to create a design concept for a rotary tray dryer for drying beef patties as an effort to replace the frying process. The research method used an engineering design approach which included design analysis, functional design and structural design of rotary tray dryer.
Component Analysis based Hybrid Face Recognition System using Artificial Neural Network
Authors: Yesu D Kolhandai , Shandilya Shivam , Ankit Kumar
Published: March 2021

Digital Face Recognition is a problem in Computer Vision, Computer Human Interface and especially in Biometrics for identifying and verifying the identity of persons. This paper presents a novel Hybrid Face Recognition System (FRS) basing on and modifying the existing component analysis based FRS.
Faraday Cup for Electron Flux Measurements on the Microtron MT 25
Authors: Vognar M. , Šimáně Č. , Chvátil D.
Published: March 2021

The basic criteria for constructing of an evacuated Faraday cup for precise measurement of 5 to 25 MeV electron beam currents in air from a microtron are established. The Faraday cup, built in the microtron laboratory of the Faculty of Nuclear Sciences and Physical Engineering of CTU Prague, is described together with the electronic chain and its incorporation in the measuring line on the beam. Measures to reduce the backward escape of electrons are explained. The range of currents is from 10–5 to 10–10 A. The diameter of the Al entry window of the Faraday cup is 1.8 cm, and its area is 2.54 cm2. The thickness of the entry window is 0.1 mm.
Evaluation of Water Resistance and Diffusion Properties of Paint Materials
Authors: Drchalová J. , Poděbradská J. , Maděra J. , Černý R.
Published: March 2021

A simple method is presented for evaluating the water-proofness quality of paints on lining materials. The method is based on measuring the integral capillarity in dependence on time, and then comparing this value to the value determined for the basic lining material. Measurements of the effective water vapor permeability then provide information on the risk of condensation which may increase after applying the paint. A practical application of the method is performed with four Karlocolor paints on glass concrete substrates. All the Karlocolor paints are found to be very effective materials for driven rain protection. The diffusion properties of all the paints are found to be excellent.
Experimental Investigations on Drying of Porous Media Using Infrared Radiation
Authors: Haghi A. K.
Published: March 2021

Increased interest is being shown in infrared drying today because of the environmental and technological advantages offered by this method. In order to assess the advantages of this drying process, extensive trials have been carried out. The objective of this investigation was to study the drying rate of infrared drying. This was achieved with the use of scanning pyrometer and image analysis.
Reliability - Based Designof Precast Buildings
Authors: Kalousková M. , Novotná E. , Šejnoha J.
Published: March 2021

We present a numerical analysis of a precast structure regarding random properties of the material characteristics of joints, as well as the random character of loading, especially due to temperature impact. Using FEM we compare some of our results with a deterministic nonlinear solution.
A Logic Object and its State
Authors: Bokr J. , Jáneš V.
Published: March 2021

This paper shows not only that the state of an objecty parameterizes the dyad (stimulus, response) but that it is also the performer of the state transition initiated by the stimulus. Thus, the logic object is a feedback composition of the logic pseudoobject and the static logic object. It is also stated that, without considering the new role of the state, the content of the concept "state" cannot be completely explained. The current intuitive conception of canonical decomposition of an entity is confronted with the exactly introduced decomposition and with the mentioned division of the logic object into a pseudoobject and a static object.
Modelling of Highway Runoff Quantity and Quality
Authors: Elsayed Ashraf El-Shahat , Grünwald A. , Synáčková M. , Slavíček M.
Published: March 2021

The stormwater Management Model (SWMM) is a well-known stormwater runoff-simulation model. It is a deterministic, spatially distributed model for calculation of runoff quantity and quality. The aim of this study was to predict highway runoff characteristics using data from different highway catchments. The SWMM was used in the simulation process and the predicted data was verified using monitoring data collected from Prague-Plzeň highway for both total suspended solids and organic compounds. The analyzed data indicated that the simulated TSS, BOD5 concentrations lie within the range of the measured data and both data sets are considered highly polluted with respect to the specification limits. The analyzed data also show that the first flush of runoff is the most polluted, and is responsible for contamination of retention and/or received waters.
Rapid Prediction of Configuration Aerodynamics in the ConceptualDesign Phase
Authors: Munro C. , Krus P.
Published: March 2021

Conceptual aircraft design is characterised by the requirement to analyse a large number of configurations rapidly and cost effectively. For unusual configurations such as those typified by unmanned combat air vehicles (UCAVs) adequately predicting their aerodynamic characteristics through existing empirical methods is fraught with uncertainty. By utilising rapid and low cost experimental tools such as the water tunnel and subscale flight testing it is proposed that the required aerodynamic characteristics can rapidly be acquired with sufficient fidelity for the conceptual design phase. Furthermore, the initial design predictions can to some extent be validated using flight-derived aerodynamic data from subscale flight testing.
The Validation of Computer-based Models in Engineering: Some Lessons from Computing Science
Authors: Murray-Smith D. J.
Published: March 2021

Questions of the quality of computer-based models and the formal processes of model testing, involving internal verification and external validation, are usually given only passing attention in engineering reports and in technical publications. However, such models frequently provide a basis for analysis methods, design calculations or real-time decision-making in complex engineering systems. This paper reviews techniques used for external validation of computer-based models and contrasts the somewhat casual approach which is usually adopted in this field with the more formal approaches to software testing and documentation recommended for large software projects. Both activities require intimate knowledge of the intended application, a systematic approach and considerable expertise and ingenuity in the design of tests. It is concluded that engineering degree courses dealing with modelling techniques and computer simulation should put more emphasis on model limitations, testing and validation.
Computational Investigation of Flows in Diffusing S-shaped Intakes
Authors: Menzies R.
Published: March 2021

This paper examines the flow in a diffusing s-shaped aircraft air intake using computational fluid dynamics (CFD) simulations. Diffusing s-shaped ducts such as the RAE intake model 2129 (M2129) give rise to complex flow patterns that develop as a result of the offset between the intake cowl plane and engine face plane. Euler results compare favourably with experiment and previous calculations for a low mass flow case. For a high mass flow case a converged steady solution was not found and the problem was then simulated using an unsteady flow solver. A choked flow at the intake throat and complex shock reflection system, together with a highly unsteady flow downstream of the first bend, yielded results that did not compare well with previous experimental data. Previous work had also experienced this problem and a modification to the geometry to account for flow separation was required to obtain a steady flow.RANS results utilising a selection of turbulence models were more satisfactory. The low mass flow case showed good comparison with experiment and previous calculations. A problem of the low mass flow case is the prediction of secondary flow. It was found that the SST turbulence model best predicted this feature. Fully converged high mass flow results were obtained. Once more, SST results proved to match experiment and previous computations the best. Problems with the prediction of the flow in the cowl region of the duct were experienced with the S-A and k-w models. One of the main problems of turbulence closures in intake flows is the transition of the freestream from laminar to turbulent over the intake cowl region. It is likely that the improvement in this prediction using the SST turbulence model will lead to more satisfactory results for both high and low mass flow rates.
Deriving Triggers from Integrity Constraint Specifications in the Database Management Systems
Authors: Badawy M. , Richta K.
Published: March 2021

Supporting integrity constraints is essential for database systems. Integrity constraints are used to ensure that the data in a database complies with rules that have been set to establish accurate and acceptable information for a database. Triggers provide a very powerful and flexible means to realize effective constraint enforcing mechanisms. Implementing triggers based on constraint specifications follows some simple rules that are basically independent of a particular commercial database system. This paper gives these rules, which can be used to derive triggers from constraint specifications. A comparison of advantages of constraints and triggers is also given in this paper.
The Risks of Investments in Transport Infrastructure Projects
Authors: Pokorná O. , Mocková D.
Published: March 2021

Investment decisions should not be taken without an in-depth analysis of the risks. This is an important stage in project preparation and should be performed simultaneously with the planning of the financial operations. Infrastructure development requires that project risks and responsibilities be assigned to the public or private entity that is best able to manage them. The risks and their financial impacts are usually not quantified equally by all parties. Each party views the given risks according to the guarantees provided. These guarantees are related to the form of participation in the project.
A Mathematical Approach for Evaluation of Surface Topography Parameters
Authors: Haghi A. K.
Published: March 2021

The probability characteristics of surface topography parameters described by the composition of the deterministic component and the homogeneous random normal field were analysed. Formulae for the calculation of the mathematical expectation of the Ras parameter and the evaluation of its variance are given.
Reducing Ultrasonic Signal Noise by Algorithms based on Wavelet Thresholding
Authors: Kreidl M. , Houfek P.
Published: March 2021

Traditional techniques for reducing ultrasonic signal noise are based on the optimum frequency of an acoustic wave, ultrasonic probe construction and low-noise electronic circuits. This paper describes signal processing methods for noise suppression using a wavelet transform. Computer simulations of the proposed testing algorithms are presented.
Optimisation and Just-in-Time
Authors: Beran V.
Published: March 2021

Arranging production activities to fit in with other construction activities is one of the basic ideas of the Just-in-Time approach. In the construction industry it has never been very fully applied. This is a mistake [1]. Construction works, particularly expensive parts of them, are a field where the approach can be and should be applied.
Measurement of Moisture Fields in the Bridge Structure of Charles Bridge
Authors: Římal J.
Published: March 2021

This paper describes measurements of the moisture field of Charles Bridge in Prague. The measurements were scheduled to cover a one-year cycle, including the spring, summer, autumn and winter, in order to monitor the behaviour of the bridge structure over a period of one year.