bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pedestal analysis of jitter in a 20.97  GHz regeneratively mode-locked laser formed with a short polarization-maintaining fiber amplifier
Authors: Ng W. , Stasyuk V. , Reddy K. V. 
Published: February 2021

We demonstrated a 20.97 GHz regeneratively mode-locked Er fiber laser that has a short ring length of 5.84 m. The short active ring enabled large filter-rejection of adjacent supermodes during extraction of its clock signal for regenerative feedback. Very stable mode locking was observed with the generation of

∼

5.5

p
s

Gaussian pulses. A characterization of the noise pedestals in the photodetected first and second harmonics of the mode-locked pulses indicated there was cross-correlated coupling between the timing and amplitude jitter. From an analysis of the noise pedestals in these harmonics, as well as the noise spectrum at baseband, we estimated an amplitude jitter of

∼

0.19

%

, and a timing jitter of

∼

60

f
s

. Using a generalized harmonic analysis approach, we estimated a cross correlation of 0.11% between the timing and amplitude jitter.
Transmission characteristics of electromagnetic waves in 2D tunable plasma photonic crystals
Authors: Liang Yichao , Liu Zhen , Lin Liguang , Peng Jun , Liu Rubing , Lin Qi 
Published: February 2021

The transmission characteristics of electromagnetic waves in a 2D plasma photonic crystal (PPC) in the frequency range of 1–12 GHz are investigated by experiments and numerical simulations. For PPC composed of discharge plasma tubes, the transmission characteristics of electromagnetic waves in PPC can be adjusted by changing the discharge current. The transmission characteristics of PPC in different array arrangements and working modes are obtained experimentally; the finite difference time domain (FDTD) method is used to obtain the band structure of PPC in different array arrangements and working modes. The results show the following: the simulation results of the layered model are close to the experimental results; whether the discharge plasma tube is working or not has an important influence on the transmission characteristics of PPC; and Bragg scattering and the localized surface plasmons (LSPs) are the main reasons for the generation of the bandgap. The increase in electron density causes the bandgap to move to higher frequencies and increases the number of bandgaps. The research results can be used as a reference for the evaluation of electromagnetic properties of 2D PPCs and the design of new devices such as plasma antennas.
Optical 1-bit comparator based on two-dimensional photonic crystals
Authors: Parandin Fariborz , Kamarian Reza , Jomour Mohamadreza 
Published: February 2021

A comparator is one of the important combinational logic circuits. An optical comparator was designed and simulated based on photonic crystals. Point and linear defects were also used in the proposed optical comparator. The use of simple defect paths and the absence of ring resonators reduced the complexity of the structure. One of the characteristics of the proposed structure is that it has a very small size, which leads to the suitability of this comparator for optical integrated circuits. Another characteristic of this comparator is an increase in the optical power difference for the logical values “0” and “1,” which reduces the bit detection error in the output. This comparator is also designed to operate on the 1.55 µm wavelength, and it can be used in today’s optical telecommunication circuits.
On-chip optical true time delay lines based on subwavelength grating waveguides
Authors: Wang Yue , Sun Hao , Khalil Mostafa , Dong Wei , Gasulla Ivana , Capmany José , Chen Lawrence R. 
Published: February 2021

An optical true time delay line (OTTDL) is a fundamental building block for signal processing applications in microwave photonics and optical communications. Here, we experimentally demonstrate an index-variable OTTDL based on an array of 40 subwavelength grating (SWG) waveguides in silicon-on-insulator. Each SWG waveguide in the array is 34 mm long and arranged in a serpentine manner; the average incremental delay between waveguides is about 4.7 ps, and the total delay between the first and last waveguides is approximately 181.9 ps. The waveguide array occupies a chip area of

∼

6.5

m
m

×

8.7

m
m

=

56.55

m
m

2

. The proposed OTTDLs bring potential advantages in terms of compactness as well as operation versatility to a variety of microwave signal processing applications.
Micro-electromechanical-system-tuned resonant filters spanning the 8–12  µm band
Authors: Ko Y. H. , Lee K. J. , Das S. , Gupta N. , Magnusson R. 
Published: February 2021

The spectral band covering

∼

8

−

12

µ

m

is atmospherically transparent and therefore important for terrestrial imaging, day/night situational awareness systems, and spectroscopic applications. There is a dearth of tunable filters spanning the band. Here, we propose and demonstrate a new, to the best of our knowledge, tunable-filter method engaging the fundamental physics of the guided-mode resonance (GMR) effect realized with a non-periodic lattice. The polarization-dependent filter is fashioned with a one-dimensional Ge grating on a ZnSe substrate and interrogated with a

∼

1.5

m
m

Gaussian beam to show clear transmittance nulls. To expand the tuning range, the device parameters are optimized for sequential operation in TM and TE polarization states. The theoretical model exhibits a tunable range exceeding 4 µm, thus covering the band fully. In the experiment, a prototype device exhibits a spectral range of 8.6–10.0 µm in TM and 9.9–11.7 µm in TE polarization or

>

3

µ

m

total. With additional efforts in fabrication, we expect to achieve the full range.
800  Gb/s/200  m FSO link with a WDM-PAM4 scheme and SLM-based beam tracking technology
Authors: Lu Hai-Han , Huang Xu-Hong , Tsai Wen-Shing , Feng Chao-Yu , Chou Cing-Ru , Chen Yi-Hao , Huang Yu-Ting , Nainggolan Agustina 
Published: February 2021

An 800 Gb/s/200 m free-space optical (FSO) link with a wavelength-division multiplexing (WDM)-four-level pulse amplitude modulation (PAM4) scheme and spatial light modulator (SLM)-based beam tracking technology is constructed. To the best of our knowledge, this is the first one that adopts a WDM-PAM4 scheme and an SLM-based beam tracking technology to simultaneously afford a high transmission capacity of 800 Gb/s and resolve the laser beam misalignment problem due to target device movement. By adopting a 16-wavelength WDM-PAM4 scheme, the transmission capacity of the FSO link is considerably enhanced with an 800 Gb/s (

50

G
b

/

s

P
A
M
4

/

λ
×

16

λ

) total capacity. By deploying an SLM-based beam tracking technology, the laser beam misalignment problem is practically resolved for providing an FSO link with high link accessibility. This demonstrated WDM-PAM4 FSO link fully meets the requirements of high-speed, long-reach, and high-reliability transmissions.
Novel health system strategies for tuberculin skin testing at primary care clinics: Performance assessment and health economic evaluation
Authors: Van Ginderdeuren Eva , Bassett Jean , Hanrahan Colleen F. , Mutunga Lillian , Van Rie Annelies 
Published: February 2021

Background
Tuberculin skin test (TST) for guiding initiation of tuberculosis preventive therapy poses major challenges in high tuberculosis burden settings.

Methods
At a primary care clinic in Johannesburg, South Africa, 278 HIV-positive adults self-read their TST by reporting if they felt a bump (any induration) at the TST placement site. TST reading (in mm) was fast-tracked to reduce patient wait time and task-shifted to delegate tasks to lower cadre healthcare workers, and result was compared to TST reading by high cadre research staff. TST reading and placement cost to the health system and patients were estimated. Simulations of health system costs were performed for 5 countries (USA, Germany, Brazil, India, Russia) to evaluate generalizability.

Results
Almost all participants (269 of 278, 97%) correctly self-identified the presence or absence of any induration [sensitivity 89% (95% CI 80,95) and specificity 99.5% (95% CI 97,100)]. For detection of a positive TST (induration ≥ 5mm), sensitivity was 90% (95% CI 81,96) and specificity 99% (95% CI 97,100). TST reading agreement between low and high cadre staff was high (kappa 0.97, 95% CI 0.94, 1.00). Total TST cost was 2066 I$ (95% UI 594, 5243) per 100 patients, 87% (95% UI 53, 95) of which were patient costs. Combining fast-track and task-shifting, reduced total costs to 1736 I$ (95% UI 497, 4300) per 100 patients, with 31% (95% UI 15, 42) saving in health system costs. Combining fast-tracking, task-shifting and self-reading, lowered the TST health system costs from 16% (95% UI 8, 26) in Russia to 40% (95% UI 18, 54) in the USA.

Conclusion
A TST strategy where only patients with any self-read induration are asked to return for fast-tracked TST reading by lower cadre healthcare workers is a promising strategy that could be effective and cost-saving, but real-life cost-effectiveness should be further examined.
The relative contribution of intraspecific variation and species turnover to the community-level foliar stoichiometric characteristics in different soil moisture and salinity habitats
Authors: Tusifujiang Yelike , Zhang Xueni , Gong Lu 
Published: February 2021

BackgroundTrait-based approaches have been used to demonstrate the responses of plant functional traits to environmental change may manifest both among- and/or within-species. However, how community-level foliar stoichiometric characteristic variations respond to aridity and salinity is still not well-known.MethodsWe calculated community weighted means (CWMs) and non-weighted means (CMs) of foliar C, N, and P concentrations (and their ratios) in a dryland plant community respond to high (HSW) and low soil moisture and salinity (LSW). Based on a sum of squares decomposition method, we determined the relative contributions of intraspecific variation and species turnover in both HSW and LSW habitats.ResultsThe CWMs of foliar C, C:N and C:P, and CM of N in the HSW habitat were significantly greater than those in the LSW habitat. The trait variations in two habitats were mainly driven by intraspecific variation, and its contribution to trait variation mostly declined with the decrease of soil moisture and salinity. The CWMs of foliar C-related stoichiometric characteristics were mainly dominated by species turnover in both habitats. Moreover, the contribution of species turnover to C and C:P variations showed an increasing trend in the LSW habitat. For CWMs, negative covariations between intraspecific variation and turnover occurred in HSW and positive covariations (except N:P) occurred in LSW; however, CMs were generally positively correlated in both habitats.ConclusionsThe intraspecific variation declined as drought stress intensified, which indicates that the adaptability of desert plants declined when the stress changed from salinity to aridity. The total variation of C-related traits in both habitats were mainly dominated by species turnover. These findings highlight the importance of intraspecific variation in driving desert plant response of community functional composition to salt stress, and the joint role of intraspecific variation and species turnover in resisting drought stress.
Relationship dynamics and anticipated stigma: Key considerations for PrEP use among Tanzanian adolescent girls and young women and male partners
Authors: Jani Nrupa , Mathur Sanyukta , Kahabuka Catherine , Makyao Neema , Pilgrim Nanlesta 
Published: February 2021

Objectives
We examined key gender, interpersonal and community dynamics influencing PrEP acceptability among adolescent girls and young women (AGYW) and their male partners.

Methods
We administered 12 in-depth interviews (IDI) to partnered, or married AGYW aged 15–24 years living without HIV, and 16 IDIs to male partners living without HIV aged 18 or older, partnered or married to an AGYW in Tanzania. Card sorting, a participatory qualitative method for facilitating systematic discussion, was used to identify attitudes, values, and desires that would influence PrEP acceptability.

Results
Relationship distrust, partner communication about HIV risk, and need to control HIV risk were highly influential considerations for PrEP use. AGYW and male partners both wanted to discuss PrEP use amidst relationship distrust, while most male partners encouraged AGYW PrEP use for shared protective benefit. Anticipated stigma of being perceived as a person living with HIV, as a result of PrEP use, was a deterrent for both AGYW and male partners while AGYW also feared additional stigma of being considered sexually promiscuous.

Conclusions
Couples counseling for PrEP uptake and adherence might be a well-placed strategy for couples who are living without HIV to educate one another about the relationship benefits of using PrEP, thereby increasing its acceptance and adherence, addressing unequal power dynamics, and reducing associated relationship distrust. Community awareness and education about PrEP can help curb persistent PrEP stigma, including intersectional stigma.
Factors influencing the delivery and uptake of early infant diagnosis of HIV services in Greater Accra, Ghana: A qualitative study
Authors: Ankrah Antoinette Kailey , Dako-Gyeke Phyllis 
Published: February 2021

BackgroundEarly Infant Diagnosis (EID) of HIV and timely initiation of Antiretroviral Therapy (ART) can significantly reduce morbidity and mortality of HIV infected infants. Despite the benefits of early infant testing, the coverage of EID of HIV services is still low in Sub-Saharan Africa, including Ghana.ObjectivesTo ascertain the factors that facilitate or hinder the delivery and uptake of EID of HIV services.MethodsThe study is a cross-sectional exploratory qualitative research conducted in two health facilities in the Greater Accra Region of Ghana. Respondents (n = 50) comprising health workers (n = 20) and HIV positive mothers (n = 30) were purposively sampled and engaged in in-depth interviews. The Nvivo 11 software and the Braun and Clarke’s stages of thematic analysis were used in coding data and data analysis respectively.ResultsThe study found that health system factors such as inadequate Staff with sample collection skills, unavailability of vehicles to convey samples to the reference laboratory for analysis, the long turnaround time for receipt of Polymerase Chain Reaction (PCR) results, inadequate and frequent breakdown of PCR machine hindered EID service delivery. On the other hand, adequate knowledge of health workers on EID, availability of Dried Blood Spot (DBS) cards and the adoption of task shifting strategies facilitated EID service delivery. Factors such as the denial of HIV status, non-completion of the EID process due to frustrations encountered whiles accessing service and delay in receipt of PCR results served as barriers to mother’s utilisation of EID services for their exposed infants. The study also identified that adequate knowledge of EID, perceived importance of EID, financial stability as well as financial support from others and the positive attitudes of health workers facilitated HIV positive mother’s uptake of EID services for their exposed infants.ConclusionThe factors attributing to the low coverage of EID of HIV services must be promptly addressed to improve service delivery and uptake.
Impact of COVID-19 pandemic on the utilization of routine immunization services in Lebanon
Authors: Mansour Ziad , Arab Jinan , Said Racha , Rady Alissar , Hamadeh Randa , Gerbaka Bernard , Bizri Abdul Rahman 
Published: February 2021

Introduction
The global abrupt progression of the COVID-19 pandemic may disrupt critical life-saving services such as routine immunization (RI), thus increasing the susceptibility of countries to outbreaks of vaccine-preventable diseases (VPDs). Being endemic to several infectious diseases, Lebanon might be at increased risk of outbreaks as the utilization of RI services might have deteriorated due to the pandemic and the country’s political unrest following the October 2019 uprising. The aim of this study was to assess the changes in the utilization of RI services in both the public and private sectors following the COVID-19 pandemic.

Methods
A self-administered cross-sectional survey was completed electronically, in April 2020, by 345 private pediatricians who are registered in professional associations of physicians in Lebanon and provide immunization services at their clinics. Means of the reported percentages of decrease in the utilization of vaccination services by pediatricians were calculated. As for the public sector, an examination of the monthly differences in the number of administered vaccine doses in addition to their respective percentages of change was performed. Adjustment for the distribution of RI services between the sectors was performed to calculate the national decrease rate.

Results
The utilization of vaccination services at the national level decreased by 31%. In the private sector, immunization services provision diminished by 46.9% mainly between February and April 2020. The highest decrease rates were observed for oral poliovirus vaccine (OPV) and hepatitis A, followed by measles and pneumococcal conjugate vaccines. The number of vaccine doses administered in the public sector decreased by 20%. The most prominent reductions were detected for the OPV and measles vaccines, and during October 2019 and March 2020.

Conclusion
The substantial decrease in the utilization of RI as a result of the COVID-19 pandemic requires public health interventions to prevent future outbreaks of VPDs.
Phytochemical characterization of turnip greens (Brassica rapa ssp. rapa): A systematic review
Authors: Dejanovic Gordana M. , Asllanaj Eralda , Gamba Magda , Raguindin Peter Francis , Itodo Oche Adam , Minder Beatrice , Bussler Weston , Metzger Brandon , Muka Taulant , Glisic Marija , Kern Hua 
Published: February 2021

Objective
The Turnip (Brassica rapa L. ssp. rapa) is a leaf and root vegetable grown and consumed worldwide. The consumption of Turnip has been associated with beneficial effects on human health due to their phytochemicals that may control a variety of physiological functions, including antioxidant activity, enzyme regulation, and apoptotic control and the cell cycle. The current systematic review of the literature aims to evaluate both the profile and quantity of phytochemicals commonly found in Turnip greens and to provide perspectives for further investigation.

Methods
This review was conducted following the PRISMA guidelines. Four bibliographic databases (PubMed, Embase, Web-of-Science and Cochrane Central Register of Controlled Trials) were searched to identify published studies until April 8th, 2020 (date last searched) without data and language restriction. Studies were included if they used samples of Turnip greens (the leaves), and evaluated its phytochemical content. Two reviewers independently evaluated the titles and abstracts according to the selection criteria. For each potentially eligible study, two reviewers assessed the full-texts and independently extracted the data using a predesigned data extraction form.

Results
Based on the search strategy 5,077 potentially relevant citations were identified and full texts of 37 studies were evaluated, among which 18 studies were eligible to be included in the current review. The majority of included studies were focused on identification of glucosinolates and isothiocyanates (n = 14, 82%), four studies focused on organic acids, and five studies reported phenolic component profile in Turnip greens. Among included studies nine studies (50%) provided information on phytochemical’s content. We found 129 phytochemicals (19 glucosinolates, 33 glucosinolate-breakdown products, 10 organic acids and 59 polyphenolic compounds) reported in Turnip greens. Flavonoids were mainly present as quercetin, kaempferol and isorhamnetin derivatives; while aliphatic forms were the predominant glucosinolate (gluconapin was the most common across five studies, followed by glucobrassicanapin). In general, the phytochemical content varied among the leaves, tops and Turnip roots.

Conclusions
Emerging evidence suggests the Turnip as a substantial source of diverse bioactive compounds. However, detailed investigation on the pure compounds derived from Turnip green, their bioavailability, transport and metabolism after consumption is further needed. Additional studies on their biological activity are crucial to develop dietary recommendations on the effective dosage and dietary recommendation of Turnip greens for nutrition and health.
Is a verification phase useful for confirming maximal oxygen uptake in apparently healthy adults? A systematic review and meta-analysis
Authors: Costa Victor A. B. , Midgley Adrian W. , Carroll Sean , Astorino Todd A. , de Paula Tainah , Farinatti Paulo , Cunha Felipe A. 
Published: February 2021

Background
The ‘verification phase’ has emerged as a supplementary procedure to traditional maximal oxygen uptake (VO2max) criteria to confirm that the highest possible VO2 has been attained during a cardiopulmonary exercise test (CPET).

Objective
To compare the highest VO2 responses observed in different verification phase procedures with their preceding CPET for confirmation that VO2max was likely attained.

Methods
MEDLINE (accessed through PubMed), Web of Science, SPORTDiscus, and Cochrane (accessed through Wiley) were searched for relevant studies that involved apparently healthy adults, VO2max determination by indirect calorimetry, and a CPET on a cycle ergometer or treadmill that incorporated an appended verification phase. RevMan 5.3 software was used to analyze the pooled effect of the CPET and verification phase on the highest mean VO2. Meta-analysis effect size calculations incorporated random-effects assumptions due to the diversity of experimental protocols employed. I2 was calculated to determine the heterogeneity of VO2 responses, and a funnel plot was used to check the risk of bias, within the mean VO2 responses from the primary studies. Subgroup analyses were used to test the moderator effects of sex, cardiorespiratory fitness, exercise modality, CPET protocol, and verification phase protocol.

Results
Eighty studies were included in the systematic review (total sample of 1,680 participants; 473 women; age 19–68 yr.; VO2max 3.3 ± 1.4 L/min or 46.9 ± 12.1 mL·kg-1·min-1). The highest mean VO2 values attained in the CPET and verification phase were similar in the 54 studies that were meta-analyzed (mean difference = 0.03 [95% CI = -0.01 to 0.06] L/min, P = 0.15). Furthermore, the difference between the CPET and verification phase was not affected by any of the potential moderators such as verification phase intensity (P = 0.11), type of recovery utilized (P = 0.36), VO2max verification criterion adoption (P = 0.29), same or alternate day verification procedure (P = 0.21), verification-phase duration (P = 0.35), or even according to sex, cardiorespiratory fitness level, exercise modality, and CPET protocol (P = 0.18 to P = 0.71). The funnel plot indicated that there was no significant publication bias.

Conclusions
The verification phase seems a robust procedure to confirm that the highest possible VO2 has been attained during a ramp or continuous step-incremented CPET. However, given the high concordance between the highest mean VO2 achieved in the CPET and verification phase, findings from the current study would question its necessity in all testing circumstances.

PROSPERO Registration ID
CRD42019123540.