bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants and Measurement of Neonatal Vitamin D: Overestimation of 25(OH)D in Cord Blood Using CLIA Assay Technology
Authors: Lu Mengdi , Hollis Bruce W , Carey Vincent J , Laranjo Nancy , Singh Ravinder J , Weiss Scott T , Litonjua Augusto A
Published: December 2019

Context

Vitamin D (VD) deficiency in pregnancy and the neonatal period has impacts on childhood outcomes. Maternal VD sufficiency is crucial for sufficiency in the neonate, though the effect of early versus late pregnancy 25-hydroxy-vitamin D (25(OH)D) levels on neonatal levels is unknown. Furthermore, chemiluminescence immunoassays (CLIAs) are widely used, though their validity in measuring 25(OH)D specifically in cord blood specimens has not been established.

Objective

To assess the validity of a CLIA in the measurement of cord blood 25(OH)D and to evaluate maternal determinants of neonatal 25(OH)D, including early versus late pregnancy 25(OH)D levels.

Design

This is an ancillary analysis from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized, double-blinded, placebo-controlled study.

Participants and Intervention

A total of 881 pregnant women at high risk of having offspring asthma were randomized to receive VD supplementation or placebo. Serum samples were collected from mothers in early and late pregnancy and from offspring cord blood at birth. 25(OH)D levels were assayed by CLIA in all maternal and offspring samples and by LC-MS/MS in all offspring samples and a subset of 200 maternal third trimester samples.

Results

Cord blood 25(OH)D levels were higher as measured by CLIA (mean 37.13 ng/mL [SD 18.30]) than by LC-MS/MS (mean 23.54 ng/mL [SD 11.99]), with a mean positive bias of 13.54 ng/mL (SD 12.92) by Bland-Altman analysis. This positive bias in measurement by CLIA was not observed in maternal samples. Third trimester 25(OH)D was a positive determinant of neonatal 25(OH)D levels.

Conclusion

Chemiluminescence immunoassays overestimate 25(OH)D levels in human cord blood samples, an effect not observed in maternal blood samples. The quantification of 25(OH)D by CLIA should therefore not be considered valid when assayed in cord blood samples. Third trimester, but not first trimester, maternal 25(OH)D is one of several determinants of neonatal 25(OH)D status.
Circulating miR-181c-5p and miR-497-5p Are Potential Biomarkers for Prognosis and Diagnosis of Osteoporosis
Authors: Ma Jianhua , Lin Xiao , Chen Chu , Li Siyu , Zhang Shasha , Chen Zhihao , Li Dijie , Zhao Fan , Yang Chaofei , Yin Chong , Qiu Wuxia , Xiao Yunyun , Zhang Kewen , Miao Zhiping , Yang Tuanmin , Qian Airong
Published: December 2019

Context

Osteoporosis is a degenerative bone disease in aging men and women. MiRNAs associated with progressive bone loss in osteoporosis had not been clearly demonstrated.

Objective

The evaluation of the differentially expressed miRNAs in the bone tissue and serum of osteoporotic women with aging.

Methods

MiRNAs GeneChip and real-time PCR were used to screen differently expressed miRNAs in bone tissues of 21 osteoporotic women ages 60–69 years and 80–89 years. Identified miRNAs were detected in the serum of the validation cohort, which consisted of 14 healthy premenopausal women and 86 postmenopausal women with osteopenia or osteoporosis. MiR-181c-5p and miR-497-5p expression were validated in aging and OVX mice models, and osteoblasts. Their role in osteogenesis was validated in vitro.

Results

Twenty-four miRNAs showed the highest differential expression in bone tissues of osteoporotic women in initial screening. Among them, four miRNAs were identified both in the bone tissue and serum in the validation cohort. The levels of miR-181c-5p and miR-497-5p were decreased in the serum of postmenopausal women with osteopenia or osteoporosis, but increased in subjects treated with bisphosphonate plus calcitriol. MiR-181c-5p and miR-497-5p were significantly downregulated in the bone tissue of aging and OVX mice models, and upregulated during the osteogenic differentiation of hFOB1.19 and MC3T3-E1 cells. Overexpression of miR-181c-5p and miR-497-5p promoted the differentiation and mineralization of osteoblasts.

Conclusions

MiR-181c-5p and miR-497-5p are involved in bone metabolism and associated with progressive bone loss of due to osteoporosis, suggesting that circulating miR-181c-5p and miR-497-5p might act as potential biomarkers for monitoring the effects of antiosteoporotic therapies or the diagnostic approach.
Anesthetic Management of a Parturient With Cardiac Tamponade due to Heart Perforation by an Atrial Septum Defect Repair Device: A Case Report
Authors: Chloropoulou Pelagia P. , Konstantinou Fotios , Nikitidis Nikos , Tsikouras Panagiotis , Vogiatzaki Theodosia
Published: December 2019

With the ongoing development of safer anesthesia, pregnant women with cardiac disease are presenting more frequently for cesarean delivery. We report the successful anesthetic management of a 31-year-old parturient, on long-term anticoagulant therapy, who presented with acute cardiac tamponade due to perforation of the left atrium from a dislodged atrial septum defect occluder. The cesarean delivery was followed by temporary repair of the perforation without extracorporeal circulation (EC) due to concerns about excessive postpartum bleeding. The definitive repair of the atrial defect and the perforation were successfully accomplished under (EC) 5 days after delivery.
A Multidisciplinary Perioperative Intervention to Improve Positive Airway Pressure Adherence in Patients With Obstructive Sleep Apnea: A Case Series
Authors: Wong Jimmy K. , Rodriguez Elayne M. , Wee-Tom Bradford , Lejano Michael , Kushida Clete A. , Howard Steven K. , Memtsoudis Stavros G. , Mariano Edward R.
Published: December 2019

Positive airway pressure (PAP) adherence in patients with obstructive sleep apnea (OSA) remains low despite known benefits. The postoperative inpatient period may represent a unique opportunity to address technical issues and promote self-efficacy, 2 important factors determining adherence, which may result in patients’ seeking outpatient sleep medicine follow-up. We report our experience in developing a perioperative multidisciplinary intervention of reintroducing PAP therapy to nonadherent OSA patients with the intent of motivating patients to return to their outpatient sleep medicine clinics.
In Situ Preparation and Unique Electrical Behaviors of Gold@Hollow Polyaniline Nanospheres through Recovery of Gold from Simulated e-Waste
Authors: Tian Xiangyu , Zhang Bin , Hou Jie , Gu Minchao , Chen Yu
Published: December 2019

One of the most effective ways to solve the dilemma between resources shortages and increasing demand is to develop a cost-effective approach for recovery and reuse of the precious metals (especially Au and Ag) derived from e-wastes (electronic devices and the components thereof), which will most likely be driven by breakthroughs in environmentally friendly methodologies that combine the economy of scale with function. Here a facile and novel approach is described for the recovery of gold from simulated e-wastes by using hollow polyaniline nanospheres (P(VAn-g-PANI)) in which PANI and its derivatives can not only be used to reduce Au3+ to Au0 from the metal salts, but also be used to stabilize the achieved polymer nanosphere-supported Au nanoparticles (Au@P(VAn-g-PANI)). The Au@P(VAn-g-PANI) was directly used to fabricate electronic devices with a configuration of Al/Au@P(VAn-g-PANI) + PVA]/ITO, in which Au@P(VAn-g-PANI) was uniformly integrated into poly(vinyl alcohol) (PVA) as electrically insulating matrix. When the Au/N molar ratio in P(VAn-g-PANI) reached 1:10, the device could be electrically erased and reprogrammed showing typical nonvolatile rewritable memory effect, with an ON/OFF current ratio exceeding 105, a turn-on voltage of −1.85 V and a turn-off voltage of 2.90 V. In the case of Au/N molar ratio of 1:1, the corresponding device exhibited conductor behaviour. This work opens a way that can both recycle gold in situ from e-wastes and fabricate electronic devices by using polymer nanosphere-supported Au nanoparticles.
The Cascade Analysis Tool: software to analyze and optimize care cascades
Authors: Kedziora David J , Abeysuriya Romesh , Kerr Cliff C , Chadderdon George L , Harbuz Vlad-Ștefan , Metzger Sarah , Wilson David P , Stuart Robyn M
Published: December 2019

Introduction: Cascades, which track the progressive stages of engagement on the path towards a successful outcome, are increasingly being employed to quantitatively assess progress towards targets associated with health and development responses. Maximizing the proportion of people with successful outcomes within a budget-constrained context requires identifying and implementing interventions that are not only effective, but also cost-effective.

Methods: We developed a software application called the Cascade Analysis Tool that implements advanced analysis and optimization methods for understanding cascades, combined with the flexibility to enable application across a wide range of areas in health and development. The tool allows users to design the cascade, collate and enter data, and then use the built-in analysis methods in order to answer key policy questions, such as: understanding where the biggest drop-offs along the cascade are; visualizing how the cascade varies by population; investigating the impact of introducing a new intervention or scaling up/down existing interventions; and estimating how available funding should be optimally allocated among available interventions in order to achieve a variety of different objectives selectable by the user (such as optimizing cascade outcomes in target years). The Cascade Analysis Tool is available via a user-friendly web-based application, and comes with a user guide, a library of pre-made examples, and training materials.

Discussion: Whilst the Cascade Analysis Tool is still in the early stages of existence, it has already shown promise in preliminary applications, and we believe there is potential for it to help make sense of the increasing quantities of data on cascades.
REVIEW AND ANALYSIS OF LESSONS LEARNED HANDWRITING EXPERTISE AS A WAY TO IDENTIFY PROBLEMS AND WAYS TO SOLVE THEM IN EXISTING METHODS OF HANDWRITING RESEARCH
Authors: Lozben Vladlena Vyacheslavovna , Gajkova Luybov Vadimovna
Published: December 2019

In today’s environment, information security needs constant improvement. Therefore, biometric technologies are becoming increasingly important as a key area of information protection, contributing to the widespread introduction of biometric systems across firms and organizations.

Purpose: in the course of handwriting research, human participation is a prerequisite for handwriting expertise, which entails certain problems in the field of biometric expertise, the emphasis on which is contained in the article.

Methodology: tools and methods are considered to reduce the impact of problems on the process of handwriting examination: popular scientific methods of phase and case analysis and synthesis; Mathematical and simulation modeling methods and tools.

Results: in order to identify approaches to reducing subjectivity of expert’s conclusions, a review and analysis of existing solutions was carried out, as a result of which a comparative characteristic of approaches to solving the problem of handwriting examination was drawn up.

Scope of results: the results of this study will help the organization’s leadership in information security.
SPECIFICS OF PROJECT MANAGEMENT APPLICATION IN AGRIBUSINESS
Authors: Korshikova Marina Viktorovna , Svistunova Inna Georgievna
Published: December 2019

This article discusses the features of project management, the possibility of its application in the organizations of the agro-industrial complex. The analysis of the structure of the agro-industrial complex was made, which allowed to allocate the fourth sphere of organization and management. The features of cost accounting in crop production are revealed and the limitations of the possibility of using the current classification as a source of information in project management are proved. The ways of updating of accounting information are offered. The factors contributing to the spread of project management in agriculture are identified. The allocation of innovative work and undertakings to projects implies the application of project management methods to them, which differ from operational management techniques. Using project management methods allows you to fulfill three main limitations of the project – meet deadlines, do not exceed the budget and perform the amount of work with the declared quality.

Purpose – determination of methods for the application of project management in the agricultural sector.

Methodology the article used statistical and economic analysis methods.

Results: the most used methods and techniques of cost accounting are identified that are the result of organizational, technological and industry-specific features of production.

Practical implications the obtained results should be applied to agricultural entities in order to implement the principles of project management.
IS TEACHING SEROTONIN POSSIBLE?
Authors: Panfilova Alvina Pavlovna , Loginova Natalya Anatolyevna
Published: December 2019

State of the issue: the article describes the modern educational technology «education» in the framework of the development of an interactive educational environment, shows its close connection with the idea of «joyful learning» described by I.G. Pestalozzi in the 18th century and development trajectories in the transition to a digital economy.

Research methods: in the article, methods were used to achieve the goal: grouping, comparison, analysis, synthesis.

Research results: as a result of the study, the features of interactive learning in the game interaction mode were identified and substantiated, in particular: practical validity (learning more successfully with the expressed usefulness of the knowledge gained); additional training (including independent study, but with a soft accompaniment of an educational intermediary – scaffolding); distributed learning, providing wide access to the educational resources of many users, in which all trainees study in different ways, at different time periods, in different territorial spaces.

Discussion: the course of the educational process is described, in which a comprehensive view of the discussed problem is formed, within the context of the context of joint activity. In the process of using the educational technology «education», it is possible to summarize a project, conference, training or exchange experience by uniting completely different people, avoiding possible misunderstandings and overcoming unwillingness to work together.

Conclusion: the advantages of the described educational process are formulated as part of the developmental training described by I. Pestalozzi.
DEVELOPMENT MODELING OF THE REGIONAL ECONOMY IN THE INDUSTRY 4.0 CONDITIONS
Authors: Sirotin Dmitriy Vladimirovich
Published: December 2019

The development of the Russian economy should take into account the implementation of the Industry 4.0 concept. This concept does not have clear assessment parameters. Estimating such parameters is problematic. The development of high-tech industries is one of the main objectives of the implementation of Industry 4.0. Prediction of economic development in modern conditions is possible on the basis of mathematical modeling methods. The difference in technological stage of the domestic economy determines the feasibility of a regional approach. Agent-based modeling is the optimal approach to solving this problem. This approach allows simulating the activities of agents. The simulated environment sets the conditions for the agents to function. A gravitational model proposed to assess the economic system functioning environment. The proposed gravitational model allows us to assess the relationship between regions on the basis of high-tech trade. The approbation carried in the Sverdlovsk region conditions. As a result of the study established, the development of the Sverdlovsk region high-tech environment, covering the main industrial regions of The Urals, Volga and Siberian federal districts, and the Central Region.

Purpose: Construction of the spatial development an assessing model of high-tech environment in the agent-oriented model of territories economic development in the Industry 4.0 conditions.

Methodology: methods of system, structural and logical analysis, tools of gravitational modeling.

Results: The proposed gravitational model allowed us to assess the interregional interrelations of Sverdlovsk region on the basis of high-tech trade.

Practical implications: The results can be useful for assessing the environment of the economic system in the context of Industry 4.0 in the agent-oriented approach.
Skin integrity in older adults: pressure-prone, inaccessible areas of the body
Authors: Payne Drew
Published: December 2019

Good skin integrity is vital to good health because the skin acts as a barrier to microbes and toxins, as well as physical stressors such as sunlight and radiation. It is well known that the skin loses integrity with the ageing process, and this makes older adults susceptible to pressure injury. Additionally, older skin takes longer to heal where there are injuries or breaks. This article looks at what skin integrity is by briefly outlining the physiology of the skin. It discusses how skin integrity can be impaired, what can be done to maintain skin integrity and skin health, and why skin integrity is important for pressure ulcer prevention. Some of the factors that can make skin care difficult are discussed, in addition to the role of community nurses in helping patients engage in skin care. The article outlines how community nurses can identify when there is skin integrity risk or damage and support patients and carers or relatives, in maintaining skin integrity.
Caseload management framework for public health nurses in the Republic of Ireland
Authors: Pye Virginia
Published: December 2019

This article outlines the steps taken in a change management project to develop and implement a national caseload management framework for clinical nursing activities within public health nursing services in the Republic of Ireland. It involved the development of metrics, definitions, data collection resources and relevant written procedures. It was developed and implemented over a period of 12 months and involved the engagement and involvement of approximately 2000 frontline, management and administrative staff. Implementation was challenging due to the lack of software systems to collect and return data and support caseload management. Alternative IT-based data collection systems were identified, and work is ongoing to develop additional metrics and resources that will continue to support caseload management.
‘I lost my sight at 23’ – dentistry and visual impairment
Authors: Bissett Julie
Published: December 2019

Sassy Wyatt is a disability blogger and journalist. Here, she shares how she has adapted to life's challenges and discusses how you can make a difference to the next visually impaired patient who puts their trust in you and your practice
Characterization of Congenital Syphilis Cases Reported in a Brazilian Region
Authors: Da Silva Jhenifer Cristina , Silva Santos William Messias , Silva Santos Jaqueline , Halboth Nadia Veronica , Cardoso Maia Maria Ambrosina
Published: December 2019

Congenital syphilis is a challenge for health services and its characteristics is an important area of study. This study identified the profile of congenital syphilis cases reported in an inland region of the state of Minas Gerais, Brazil, from 2012 to 2016. This is a descriptive historical cohort study from 2012 to 2016, and the data were from documentary sources. The study involved detailed analysis of the compulsory notification forms registered in the Information System on Diseases of Compulsory Declaration (SINAN). For data collection, researchers created a form for subsequent quantitative data analysis approach. The data obtained were tabulated and analyzed using simple descriptive statistics and shown in tables. The data were organized into five charts and separated based on: (1) number of cases notified; (2) information about mothers whose newborns have syphilis; (3) pregnancies that culminated in the birth of newborns with congenital syphilis, diagnosis and treatment of these mothers; (4) information about newborns with syphilis; (5) diagnosis, treatment, and outcome of these newborns. The researchers of this study believe that, by enabling the identification of the profile of congenital syphilis cases reported in a Brazilian region, the results may contribute to the development of health strategies to prevent and control syphilis in mothers and their children.
Evidence-based policy, knowledge from experience and validity
Authors: Smith-Merry Jennifer
Published: December 2019

Evidence-based policy has at its foundation a set of ideas about what makes evidence valid so that it can be trusted in the creation of policy. This validity is frequently conceptualised in terms of rigour deriving from scientific studies which adhere to highly structured processes around data collection, analysis and inscription. In comparison, the knowledge gained from lived experience, while viewed as important for ensuring that policy meets the needs of the people it is trying to serve, is characterised by its tacit nature, unstructure and difficulty in transferring from one actor to another. Validity of experiential knowledge in policy arises from the connection of policy knowledge to the lived experience of individuals. This paper considers validity in this context through exploring four modes in which experiential knowledge is currently utilised within policy. The tensions surrounding validity in the policy context find resolution through the development of a situated notion of validity decoupled from structural rigour and recoupled to context.
A Rent-Seeking View of the Ageing Problem in Developed Countries
Authors: Colombatto Enrico
Published: December 2019

I Paesi industrialmente avanzati stanno sperimentando un notevole incremento nel loro tasso di dipendenza dagli anziani ed una caduta nella quota dei giovani.

Questo scritto si concentra sul problema delle pensioni, suggerendo che il peso di questi fattori dovrebbe essere correlato al modo in cui essi influiscono sul sottostante contratto tra contribuenti e altre coalizioni, ivi incluse la burocrazia e i politici.

Dal punto di vista della logica economica, non vi sarebbero ragioni per riconoscere alio Stato un potere decisionale nella redistribuzione di risorse tra eenerazioni. Il fatto che, invece, lo Stato svolga questo ruolo richiede una spiegazione delle ragioni per cui lo Stato trovi necessaria la redistribuzione.

L’esclusione dei giovani dal processo decisionale permette agli elettori ed ai politici di accordarsi su soluzioni che sono svantaggiose per le giovani generazioni.

Il sistema di pagamento delle pensioni sulla base delle entrate correnti garantisce i beneficiari che in ciascun momento le pensioni siano pagate da qualcun altro, cioè da chi in quel momento lavora.

Due tipi di soluzioni possono essere perseguiti: 1) riduzione del welfare state, con aumento delle risorse destinate alle pensioni; 2) se, però il potere della burocrazia e delle classi che usufruiscono di rendite parassitarie è molto forte, è più probabile che la spesa si stabilizzi, aumentando le imposte o riducendo le pensioni, o spostando in avanti l’età della pensione.

L’aspetto che qui viene evidenziato è che un problema può emergere se gli individui non adattano sistematicamente i loro profili di risparmio e consumo per tener conto dei futuri sviluppi demografici. Tale incapacità degli individui potrebbe richiedere l’intervento pubblico, peraltro limitato all’informazione, che sarebbe certamente di qualità migliore di quella disponibile a livello privato.
The Economics of Election Campaign Spending Limits
Authors: Palda Filip
Published: December 2019

I limiti alia spesa sono una regola importante nel «gioco» elettorale. I critici dei limiti affermano che i candidati già in carica (gli «uscenti») elaborano queste norme per tenere lontani i possibili sfidanti.

Questi ragionamenti sono interessanti, ma non poggiano su di una base empirica solida. I dati potrebbero sostenere o respingere l’opinione critica, dopo opportuno trattamento.

La tesi di quest’articolo è che se i candidati già in carica traggono vantaggio dai limiti alia spesa, tale vantaggio viene ottenuto in un modo che non è in alcun modo evidenziato dai dati.

Il vantaggio non emerge in forma di maggiori voti per i candidati in carica, ma in termini di maggiori benefici per i loro più stretti sostenitori.

Questa spiegazione va al di là di quella tradizionale sul modo in cui le limitazioni alle spese elettorali aiutano i candidati in carica. Essa può anche contribuire alia comprensione dei motivi per cui non è possibile dare una risposta definitiva alia controversia su chi trae vantaggio dai limiti alle spese elettorali.
On the Welfare Gains from Fiscal Decentralization
Authors: Oates Wallace E.
Published: December 2019

Questo lavoro esplora i vantaggi in termini di benessere derivanti dalla decentralizzazione in un sistema di governo a livelli multipli. L’analisi rivela che nei casi in cui le differenze in output locali efficienti risiedano nella domanda locale, i potenziali vantaggi in benessere dovuti alia decentralizzazione variano con l’entità di queste divergenze nella domanda e con il valore del coefficiente angolare (in termini assoluti) della curva di domanda. Al contrario, se la fonte delle differenze nei livelli efficienti dell’output locale risiede nei costi, allora l’entità dei vantaggi in benessere dovuti alia decentralizzazione fiscale varia direttamente con la grandezza delle differenze di costo intergiurisdizionale ma inversamente all’inclinazione della curva della domanda. Inoltre, quando si fa venir meno l’assunzione di «tecnologie” date, la decentralizzazione fiscale offre potenziali benefici in benessere grazie alia «sperimentazione» locale di diverse forme di programmi pubblici; il cosiddetto «federalismo di laboratorio» puo promuovere innovazione nei settore pubblico.
The Regional Policy of the European Communities and the Subsidiarity Principle
Authors: van Meerhaeghe Marcel A.G.
Published: December 2019

Il principio di «sussidiarietà» è stato utilizzato nell’ambito europeo per indicare che le decisioni non devono essere prese al livello più alto (Comunità), quando è possibile prenderle a livelli minori (Stati membri).

Dopo essersi soffermato sul principio di sussidiarietà, evidenziandone il carattere dinamico, questo scritto approfondisce la politica regionale della Comunità Europea, dapprima delineando le principali norme del Trattato di Roma che riguardano la politica regionale e poi considerando la corrispondente politica.

Vengono particolarmente approfonditi i problemi delle regioni prioritarie e i principali strumenti della politica in loro sostegno, i cosiddetti «fondi strutturali», giungendo alia conclusione che sino ad oggi tali strumenti non hanno dato luogo a risultati conformi alle aspettative.
Exhaustive dithering algorithm for 3D shape reconstruction by fringe projection profilometry
Authors: Silva Adriana , Muñoz Antonio , Flores Jorge L. , Villa Jesus
Published: December 2019

Three-dimensional (3D) shape reconstruction by projection of defocused binary patterns overcomes the nonlinearity introduced by the projector. Current patch-based procedures that generate dithered patterns are time consuming and are affected by the harmonics introduced through the tiling process. To overcome this problem, we propose a novel idea, to the best of our knowledge, to generate dithering patterns using the composition of two-dimensional patches as a stack of one-dimensional arrays obtained through an efficient deterministic approach. This procedure is a one-dimension optimization problem in the intensity domain, employing only a quarter of the fringe pitch. Furthermore, the unwanted distorting harmonics are eliminated using a Hilbert transform method. Both numerical simulations and experimental results verify the effectiveness of the proposal.
Composite gyroscope with high sensitivity in the low-velocity region and no dead zone
Authors: Jiang Weiguo , Zhang Yundong , Wang Jinfang , Ma Kai , Zhu Fuxing , Yi Guo , Tian He
Published: December 2019

In order to solve the problems of low sensitivity for traditional interference fiber-optic gyroscopes at low velocity and the existence of measurement dead zone for slow-light gyro, a composite fiber-optic gyroscope that consists of a Sagnac loop and a resonant loop is proposed in this paper. Since it combines the characteristics of the two gyroscopes, the composite gyro can meet the requirements of high sensitivity at low rotation velocity and no measurement dead zone. Loss has a significant influence on the sensitivity of the gyroscope, while the transmission coefficient also has a certain influence on it. The relative sensitivity in the low-velocity and high-velocity regions can be flexibly adjusted by tuning the length ratio of the Sagnac loop and the resonant loop to meet the practical application requirements. The proposed composite gyroscope can provide potential applications in high precision, miniaturization, and integration of the fiber-optic gyroscope.
Comparison of data-acquisition designs for single-shot edge-illumination X-ray phase-contrast tomography
Authors: Chen Yujia , Zhou Weimin , Hagen Charlotte K. , Olivo Alessandro , Anastasio Mark A.
Published: December 2019

Edge-illumination X-ray phase-contrast tomography (EIXPCT) is an emerging technique that enables practical phase-contrast imaging with laboratory-based X-ray sources. A joint reconstruction method was proposed for reconstructing EIXPCT images, enabling novel flexible data-acquisition designs. However, only limited efforts have been devoted to optimizing data-acquisition designs for use with the joint reconstruction method. In this study, several promising designs are introduced, such as the constant aperture position (CAP) strategy and the alternating aperture position (AAP) strategy covering different angular ranges. In computer-simulation studies, these designs are analyzed and compared. Experimental data are employed to test the designs in real-world applications. All candidate designs are also compared for their implementation complexity. The tradeoff between data-acquisition time and image quality is discussed.
Spectroscopic ellipsometry of inhomogeneous thin films exhibiting thickness non-uniformity and transition layers
Authors: Ohlídal Ivan , Vohánka Jiří , Buršíková Vilma , Franta Daniel , Čermák Martin
Published: December 2019

In this paper the complete optical characterization of an inhomogeneous polymer-like thin film of SiO
x
C
y
H
z
exhibiting a thickness non-uniformity and transition layer at the boundary between the silicon substrate and this film is performed using variable angle spectroscopic ellipsometry. The Campi-Coriasso dispersion model was utilized for describing the spectral dependencies of the optical constants of the SiO
x
C
y
H
z
thin film and transition layer. The multiple-beam interference model was used for expressing inhomogeneity of the SiO
x
C
y
H
z
thin film. The thickness non-uniformity of this film was taken into account by means of the averaging of the elements of the Mueller matrix performed using the thickness distribution for the wedge-shaped non-uniformity. The spectral dependencies of the optical constants of the SiO
x
C
y
H
z
thin film at the upper and lower boundaries together with the spectral dependencies of the optical constants of the transition layer were determined. Furthermore, the thickness values of the SiO
x
C
y
H
z
film and transition layer, profiles of the optical constants of the SiO
x
C
y
H
z
thin film and the rms value of local thicknesses corresponding to its thickness non-uniformity were determined. Thus, all the parameters characterizing this complicated film were determined without any auxiliary methods.
Spectral-temporal dynamics of (Al,In)GaN laser diodes
Authors: Uhlig Lukas , Wachs Matthias , Kunzmann Dominic J. , Schwarz Ulrich T.
Published: December 2019

(Al,In)GaN laser diodes have various relevant applications, especially in projection systems for virtual and augmented reality devices and in optical communication, all requiring fast modulation. This corresponds to pulses in the nanosecond to microsecond range, where a rich longitudinal mode dynamics occurs. We investigate this spectral-temporal dynamics experimentally with a streak camera system and simulate it using a longitudinal multi-mode rate equation model. We observe an interplay of effects, which have been observed selectively, such as relaxation oscillations, mode competition and inhomogeneous pumping of multiple quantum wells. A mechanism is included in the simulations to model the red-shift of the gain spectrum due to the carrier density in the quantum wells exceeding threshold density, which is amplified by inhomogeneous pumping. Mode competition leads to spectral cycles of the active mode with a noticeable jitter, which is observed in single pulse measurements in comparison to multi pulse averaged measurements where blurring occurs. Here, some statistical behavior as well as repeating patterns are investigated at the same effect. Also thermal effects as laser diode self-heating are discussed and have been measured over six orders of magnitude in time.
Iterative calibration method for measurement system having lens distortions in fringe projection profilometry
Authors: Xing Shuo , Guo Hongwei
Published: December 2019

In fringe projection profilometry, system calibration is crucial for guaranteeing the measurement accuracies. Its difficulty lies in calibrating projector parameters, especially when the projector lens has distortions, since the projector, unlike a camera, cannot capture images, leading to an obstacle to knowing the correspondences between its pixels and object points. For solving this issue, this paper, exploiting the fact that the fringe phases on a plane board theoretically have a distribution of rational function, proposes an iterative calibration method based on phase measuring. Projecting fringes onto the calibration board and fitting the measured phases with a rational function allow us to determine projector pixels corresponding to the featured points on the calibration board. Using these correspondences, the projector parameters are easy to estimate. Noting that the projector lens distortions may deform the fitted phase map thus inducing errors in the estimates of the projector parameters, this paper suggests an iterative strategy to overcome this problem. By implementing the phase fitting and the parameter estimating alternately, the intrinsic and extrinsic parameters of the projector, as well as its lens distortion coefficients, are determined accurately. For compensating for the effects of the lens distortions on measurement, this paper gives two solutions. The pre-compensation actively curves the fringes in computer when generating them; whereas when using the post-compensation, the lens distortion correction is performed in the data processing stage. Both methods are experimentally verified to be effective in improving the measurement accuracies.
Image reconstruction algorithm based on frequency-wavenumber decoupling for three-dimensional MIMO-SAR imaging
Authors: Gao Hang , Li Chao , Wu Shiyou , Zheng Shen , Li Hongwei , Fang Guangyou
Published: December 2019

In this paper, a frequency-wavenumber decoupling algorithm with high-efficiency and high-precise for three-dimensional (3-D) multiple-input-multiple-output synthetic aperture radar (MIMO-SAR) imaging is proposed. Based on one-dimensional (1-D) MIMO array combined with synthetic aperture scan along another dimension, MIMO-SAR imaging scheme allows the number of array elements to be greatly reduced compared with the two-dimensional (2-D) MIMO arrays. By multi-dimensional Fourier transforming and Method of Stationary Phase (MSP), analytical expression of the object function in the frequency-wavenumber domain was derived. By further expanding the range Fourier transform factor to its Taylor series form, the range compression can be realized by a simple fast Fourier transform (FFT) without multi-dimensional interpolation. After that, a decoupling factor was multiplied to compensate for the cross-range and range coupling in frequency domain. Finally, 2-D IFFT is carried out after rearrangement in the MIMO spatial frequency to get a fully focused 3-D image. Simulation and experimental results demonstrated that the algorithm can obtain the same high-precision images as back projection (BP) algorithm, and has the same high efficiency as range migration algorithm (RMA) while avoiding cumbersome multi-dimensional interpolation. A bistatic prototype imaging system in 0.1 THz band was designed for the proof-of-principle experiments. The 3-D reconstruction results of different targets were presented to verify the theoretical results and effectiveness of the proposed algorithm for MIMO-SAR imaging.
Single-shot, omni-directional x-ray scattering imaging with a laboratory source and single-photon localization
Authors: Dreier Erik S. , Silvestre Chantal , Kehres Jan , Turecek Daniel , Khalil Mohamad , Hemmingsen Jens H. , Hansen Ole , Jakubek Jan , Feidenhans’l Robert , Olsen Ulrik L.
Published: December 2019

Omni-directional, ultra-small-angle x-ray scattering imaging provides a method to measure the orientation of micro-structures without having to resolve them. In this letter, we use single-photon localization with the Timepix3 chip to demonstrate, to the best of our knowledge, the first laboratory-based implementation of single-shot, omni-directional x-ray scattering imaging using the beam-tracking technique. The setup allows a fast and accurate retrieval of the scattering signal using a simple absorption mask. We suggest that our new approach may enable faster laboratory-based tensor tomography and could be used for energy-resolved x-ray scattering imaging.
Metasurface lens with angular modulation for extended depth of focus imaging
Authors: Zhang Zhengren , Yang Quanlong , Gong Maohua , Chen Ming , Long Zhengwen
Published: December 2019

The depth of focus (DOF) indicates the tolerance of the imaging displacement. The axial long-focal-depth is significant in practical applications, including optical imaging and communication. The importance of extending the DOF is rapidly growing with the advance of metasurface lenses. Angular modulation, as a promising way to extend the DOF, offers an additional degree of freedom to improve the imaging quality. Here we theoretically and experimentally demonstrate an angular modulated metasurface lens for extended DOF imaging by means of applying the geometrical phase. Unlike previous studies of the geometrical phase, which is sensitive to the polarity of circular polarization incidence, the polarity of circular polarization independence and broadband characteristic of angular modulation yield the potential of robust and efficient extension of the DOF imaging, thus providing novel opportunities for highly integrated optical circuits.
Mode characteristic manipulation of random feedback interferometers in Brillouin random fiber laser
Authors: Zhou Zichao , Chen Liang , Bao Xiaoyi
Published: December 2019

The Brillouin random fiber laser (BRFL) suffers from high intensity noise that comes mainly from longitudinal mode beating at different mode frequencies. In this Letter, we propose and demonstrate that the mode characteristic of BRFL can be manipulated by distributed random feedback, which acts as the longitudinal mode filter. A theoretical model is developed for the first time, to the best of our knowledge, to analyze the mode characteristics of BRFL with different lengths of a weak fiber Bragg grating (FBG) array. In experiment, a single FBG, weak FBG array (reflection of

−

40

d
B

) at various lengths, and a Rayleigh scattering fiber are used to provide the random feedback. Both theoretical analysis and experimental results show that single longitudinal mode operation can be realized with the distributed random feedback interferometer, leading to a stable temporal intensity output of the BRFL in the time domain.
Deterministic generation of a four-component optical cat state
Authors: Hastrup Jacob , Neergaard-Nielsen Jonas Schou , Andersen Ulrik Lund
Published: December 2019

The four-component cat state represents a particularly useful quantum state for realizing fault-tolerant continuous variable quantum computing. While such encoding has been experimentally generated and employed in the microwave regime, the states have not yet been produced in the optical regime. Here, we propose a simple linear optical circuit combined with photon counters for the generation of such optical four-component cat states. This work might pave the way for the first experimental generation of fault-tolerant optical continuous variable quantum codes.
Dual-controlled switchable broadband terahertz absorber based on a graphene-vanadium dioxide metamaterial
Authors: Wang Tongling , Zhang Yuping , Zhang Huiyun , Cao Maoyong
Published: December 2019

We propose a dual-controlled switchable broadband terahertz (THz) metamaterial absorber based on a hybrid of vanadium dioxide (VO2) and graphene that demonstrates strong polarization-independent characteristics and works well at a wide range of incidence angles. The peak absorptance of the proposed absorber can be tuned from 26 to 99.2% by changing the Fermi energy of the graphene; the absorptance can be dynamically tuned from 9 to 99.2% by adjusting the conductivity of the vanadium dioxide because of its unique insulator-to-metal transition characteristic. Using these two independent controls in tandem, we found that the state of the proposed absorber can be switched from absorption (>96%) to reflection (>73.5%), and the transmittance can be tuned from 0% to 65% while maintaining broad bandwidth (1.05-1.6 THz), resulting in a better-performing switchable broadband terahertz absorber. Furthermore, we have provided a discussion of the interference theory in which the physical mechanism of the absorption is explained from an optical point of view. The absorber achieves dual-controlled absorptance switching via two independently controllable pathways, offering a new method for switching and modulation of broadband THz radiation.
Ultra-broadband nanophotonic phase shifter based on subwavelength metamaterial waveguides
Authors: González-Andrade David , Luque-González José Manuel , Gonzalo Wangüemert-Pérez J. , Ortega-Moñux Alejandro , Cheben Pavel , Molina-Fernández Íñigo , Velasco Aitor V.
Published: December 2019

Optical phase shifters are extensively used in integrated optics not only for telecom and datacom applications but also for sensors and quantum computing. While various active solutions have been demonstrated, progress in passive phase shifters is still lacking. Here we present a new type of ultra-broadband 90° phase shifter, which exploits the anisotropy and dispersion engineering in subwavelength metamaterial waveguides. Our Floquet–Bloch calculations predict a phase-shift error below

±
1.7
°

over an unprecedented operation range from 1.35 to 1.75 μm, i.e., 400 nm bandwidth covering the E, S, C, L, and U telecommunication bands. The flat spectral response of our phase shifter is maintained even in the presence of fabrication errors up to

±
20
  
nm

, showing greater robustness than conventional structures. Our device was experimentally demonstrated using standard 220 nm thick SOI wafers, showing a fourfold reduction in the phase variation compared to conventional phase shifters within the 145 nm wavelength range of our measurement setup. The proposed subwavelength engineered phase shifter paves the way for novel photonic integrated circuits with an ultra-broadband performance.
“Periodic” soliton explosions in a dual-wavelength mode-locked Yb-doped fiber laser
Authors: Liu Meng , Li Ti-Jian , Luo Ai-Ping , Xu Wen-Cheng , Luo Zhi-Chao
Published: December 2019

We report the “periodic” soliton explosions induced by intracavity soliton collisions in a dual-wavelength mode-locked Yb-doped fiber laser. Owing to the different group velocities of the two wavelengths, the mode-locked solitons centered at different wavelengths would periodically collide with each other. By using the dispersive Fourier transformation technique, it was found that each collision would induce soliton explosions, but none of them would be identical. Therefore, this phenomenon was termed as “periodic” soliton explosions. In addition, the dissipative rogue waves were detected in the dual-wavelength mode-locked state. The experimental results would be fruitful to the communities interested in soliton dynamics and dual-comb lasers.
ICTs as Juju: African inspiration for understanding the compositeness of being human through digital technologies
Authors: Nyamnjoh Francis B.
Published: December 2019

In this article, I liken information and communication technologies (ICTs) or digital technologies to what we in West and Central Africa have the habit of referring to as Juju. I invite as scholars of the digital humanities to see in the region’s belief in incompleteness and the compositeness of being human, as well as in the capacity to be present everywhere at the same time an indication that we have much to learn from the past on how best to understand and harness current purportedly innovative advances in ICTs. The idea of digital technologies making it possible for humans and things to be present even in their absence and absent even in their presence is not that dissimilar to the belief in what is often labelled and dismissed as witchcraft and magic that lends itself to a world of infinite possibilities – a world of presence in simultaneous multiplicities and eternal powers to redefine reality. The article argues in favour of incompleteness as a normal way of being. It challenges students of humanity to envisage a relationship between humans and digital technologies that is founded less on dichotomies and binary oppositions, nor on zero-sum games of conquest and superiority. If humans are present in things and things in humans, thanks to the interconnections, the flexibility and fluidity of being that come with recognition of and provision for incompleteness, it is important to see things and humans not only as intricately entangled, but also as open-ended composites.
A comparative analysis of social media messaging by African-centred LGBT refugee NGOs
Authors: Kenix Linda Jean , Abikanlu Femi
Published: December 2019

Approximately 40 per cent of countries categorize homosexuality as illegal. However, refugee status is still granted largely on the basis of the 1951 Convention Relating to the Status of Refugees, which found that a refugee is a person who has a ‘well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion’. On that basis, few countries allow sexual orientation as grounds for refugee status. Owing to the extraordinary odds of gaining successful refugee status and because lesbian, gay, bisexual and transgender (LGBT) asylum seekers are often socially isolated in their search for refugee status, there is a heightened need for non-government organization support networks for these individuals. This research explores social media from four LGBT refugee organizations, largely focused on Africa, to ascertain where the differences and similarities reside in communicating with community members, sharing information, building community and encouraging action.