bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometric Control of Harmonic Generation
Authors: Luther G. G. , Alber M. S. , Marsden J. E. , Robbins J. M.
Published: February 2023

Theoretical treatments of three and four-wave interactions are typically based on the transformation

q
j

=

ρ
j

exp

(

i

ϕ
j

)

. Using the Manley-Rowe relations and the Hamiltonian, these systems are integrated in terms of elliptic functions [1]. A new approach, which ultimately leads to the same elliptic function solutions and is also based on the Hamiltonian structure, is introduced. It yields a useful geometric picture of wave interactions and simplifies the understanding and analysis of these processes. In doing so, it facilitates the development and optimization of control strategies for wave interactions such as quasi-phase-matching [1–3].
Packet Networks using All-Optical Bit Serial Processing
Authors: Blow K.J. , Poustie A. , Manning R.J.
Published: February 2023

In the early days of computing (1940’s and 1950’s), computers were designed to operate serially as no static memory was available and storage could only be implemented using recirculating delay lines. Modem silicon based computers process data in parallel using static memory and latching logic gates. If processing is to be possible in all-optical form we believe it is necessary to return to serial techniques since it has proved difficult to keep light still and obtain latching. Recent work at Colorado [1] has used these serial techniques to implement a stored program optoelectronic computer using a combination of electronic detection to control lithium niobate gates and optical fibres to provide the optical pathways. The key feature of the bit serial design is to use the time of flight of the light to provide a natural memory and to arrange for computation to occur by appropriate synchronisation of data and control pulses. One advantage of this approach is that the optical processing is scaleable in bit rate. In this paper we will describe an all-optical implementation of these techniques, based on the Nonlinear Optical Loop Mirror (NOLM)[2] switch architecture, with application to the operation of packet switched networks.
Spatial Control of Pulses in Quadratic Non-Linear Materials
Authors: Celioni R. , Dekker J. , Sibilia C. , Bertolotti M.
Published: February 2023

Recently a great interest has been given to the propagation of self-guided beams or spatial solitary waves in quadratic media [1-9].
Theory of mixed-polarisation spatial solitons in anisotropic cubic media
Authors: Hutchings D. C. , Arnold J. M. , Parker D. F.
Published: February 2023

AlGaAs is an attractive material system for the study of the dynamics of Kerr spatial solitons, having a nonlinear coefficient around 1000 times that of silica around the communication wavelength of 1.55 µm. However there are a number of differences between AlGaAs and silica when the polarisation dependence of nonlinear refraction is considered. Cubic semiconductors can display an anisotropic third-order nonlinearity1 (although in terms of linear optics they are non-birefringent) and are also usually exploited in the vicinity of an optical resonance (e.g. just below the half-bandgap) so Kleinmann symmetry cannot be assumed. On considering the propagation of two orthogonal polarisation components in such a medium, one obtains not only self-phase-modulation, cross-phase-modulation and four-wave-mixing but now with a orientation dependence, but an additional three terms which only contribute in anisotropic media.2
Nonparaxiality stabilizes three-dimensional soliton beams in Kerr media
Authors: Sheppard A. P. , Haelterman M.
Published: February 2023

Three-dimensional (1+2D) spatial solitons have been well known since the early 1960's [1,2] as the unstable equilibrium state between self-focusing and diffraction. Theory have shown that below a certain critical power, the soliton beam diffracts away into radiation, while above this threshold, suffers catastrophic self-focusing [3,4]. However, although experiment corroborates this result, it should be noted that the 1+2D soliton instability is predicted from an incomplete mathematical model, namely, the nonlinear Schrödinger (NLS) equation that is based on the paraxial approximation. The 1+2D NLS equation makes the physically unreasonable prediction that the soliton beam will collapse to a singularity within a finite distance [3,4]. The arrest of catastrophic collapse observed experimentally has been explained by appealing to either saturation [5,6] or nonlocality [7-9] of the nonlinearity. However, the problem of singularity simply breaks up by recognizing that the paraxial model is not fit to describe a strongly collapsing beam and that the effects of nonparaxiality [10-12] and polarization coupling [13] should be incorporated into the model.
Conjugate solitons in optical fibers
Authors: Wabnitz S. , Soto-Crespo J. M.
Published: February 2023

As well-known, optical phase conjugation undoes optical signal distortions upon propagation in dispersive and nonlinear medium [1]. By generating the conjugate replica of a signal at the middle of fiber-optic transmission link, dispersive and nonlinear broadenings may be compensated for [2]. When applied to soliton systems, mid-span spectral inversion also removes other important transmission capacity-limiting effects such as pulse interactions [3]. Four-wave mixing in fibers may also be exploited for wavelength-shifting and time-demultiplexing of high-bit-rate signals. For efficient and broadband frequency conversion, pumping near the zero-dispersion wavelength of a dispersion-shifted fiber (DSF) is required [4,5]. As a result, the fiber group-velocity dispersion (GVD) has opposite signs at the signal and conjugate wavelengths. In the conjugation of ultrashort solitons, that is for DSF lengths equal or longer than the dispersion distance, the effect of finite GVD at the signal and conjugate wavelengths sets a fundamental limit to the conversion efficiency.
Efficient birefringence phase-matched blue light second-harmonic generation in KNbO3 ridge waveguides
Authors: Pliska Tomas , Fluck Daniel , Günter Peter , Gini Emilio , Melchior Hans , Beckers Lutz , Eckau Arne , Buchal Christoph
Published: February 2023

Ridged channel waveguides in KNbO3 were fabricated using a new technique involving He+ ion implantation and Ar+ ion sputtering. A continuous-wave second-harmonic power of 14 mW at 438 nm was obtained with an in-coupled fundamental power of 340 mW.
Modulational instability in a communication link exploiting a negative nonlinearity for compensation of self-phase modulation
Authors: Paré C. , Villeneuve A. , Larochelle S.
Published: February 2023

In optical communication systems, the technique of alternating dispersion is commonly used as a way to counteract the dispersive pulse broadening. The main limitations, in terms of bit-rate, then come from the fiber Kerr nonlinearity acting through self-phase modulation and four-wave mixing [1]. The recently introduced method of "dispersion management", where the dispersion compensation is only partial, appears as a very promising approach for coping with this problem (for a recent review, see [2]). It might still be worth, though, exploring alternatives such as the one suggesting that, besides alternating the sign of the dispersion parameter, one might also alternate the sign of the nonlinearity [3]. Similar, in some respect, to optical phase conjugation, this method would ensure the perfect restoration of a distorted pulse by passing it through a medium characterized by a dispersion parameter of opposite sign and exhibiting a negative nonlinearity (n2 < 0). A simplified and approximate version of this compensation scheme is illustrated in Fig.1. A material with a negative n2 (e.g. a semiconductor or a χ(2):χ(2) cascaded system) is inserted symmetrically between two gratings or two compensating fibers. Besides being more suitable to an experimental testing, this split compensator has been shown, through numerical simulations, to be effective in minimizing the impact of fiber nonlinearities on the quality of the transmitted signal in a long-haul communication system [4]. However, extensive numerical work also gives to think that, as with dispersion-managed systems [5,6], this compensation scheme might be subject to a modulation instability (MI). This paper presents a linear stability analysis which confirms this observation.
Dual-functional Polymeric Waveguide with Optical Amplification and Electro-optic Modulation
Authors: An Dechang , Yue Zuzhou , Chen Ray T.
Published: February 2023

Dichromated gelatin (DCG) has been used widely as a volume hologram emulsion for many years. A myriad of optical elements has been demonstrated using this polymeric material.1-6 In order to realize a monolithically-integrated polymer-based optical circuit, active devices such as waveguide modulators, switches, amplifiers, and lasers are needed. In this paper we report a dual-functional polymeric waveguide using the same host polymeric material for dichromated gelatin, aimed at providing not only holographic optical elements but also amplification and electro-optic (EO) switching. The host material photo-lime gelatin is co-doped with neodymium chloride hexahydrate (NdCl3·6H2O) and chlorophenol red (C19H12Cl2O5S). Neodymium chloride hexahydrate is doped to provide Nd+3 ions for optical amplification, and chlorophenol red to provide electro-optic modulation.
Maximizing scanning speed in the ultrafast laser cutting of thin materials
Authors: Du Xinpeng , Yu Xiaoming
Published: February 2023

A mathematical model is derived to predict the maximum speed of a focused laser beam in the laser cutting of thin materials. This model contains only two material parameters and is used to obtain an explicit relationship between the cutting speed and laser parameters. The model shows that there exists an optimal focal spot radius with which cutting speed is maximized for a given laser power. We compare the modeling results with experiments and find a good agreement after correcting laser fluence. This work is useful for the practical application of lasers in processing thin materials such as sheets and panels.
High-sensitivity acoustic impedance sensing based on forward Brillouin scattering in a highly nonlinear fiber
Authors: Zeng Keyan , Yang Guijiang , Xu Zuying , Song Li , Wang Liang , Tang Ming , Liu Deming
Published: February 2023

By using radial acoustic modes induced forward Brillouin scattering (FBS) in a highly nonlinear fiber (HNLF), to the best of our knowledge we have demonstrated acoustic impedance sensing with the sensitivity reaching beyond 3MHz for the first time. Benefiting from the high acousto-optical coupling efficiency, both radial acoustic modes (R0,m) and torsional-radial acoustic modes (TR2,m) induced FBS in HNLF have larger gain coefficient and scattering efficiency than those in standard single-mode fiber (SSMF). This provides better signal-to-noise ratio (SNR) and hence larger measurement sensitivity. By using R0,20 mode in HNLF, we have achieved a higher sensitivity of 3.83 MHz/[kg/(s · mm2)], in contrast to that of 2.70 MHz/[kg/(s · mm2)] when measured using R0,9 mode (with almost the largest gain coefficient) in SSMF. Meanwhile, with the use of the TR2,5 mode in HNLF, the sensitivity is measured to be 0.24 MHz/[kg/(s · mm2)], which is still 1.5 times larger than that reported when using the same mode in SSMF. The improved sensitivity would make the detection of the external environment by FBS based sensors more accurate.
Fabrication and characterization of iodine photonic microcells for sub-Doppler spectroscopy applications
Authors: Goïcoechéa Clément , Billotte Thomas , Chafer Matthieu , Maurel Martin , Jouin Jenny , Thomas Philippe , Naik Devang , Gérôme Frédéric , Debord Benoît , Benabid Fetah
Published: February 2023

We report on the development of all-fiber stand-alone iodine-filled photonic microcells demonstrating record absorption contrast at room temperature. The microcell’s fiber is made of inhibited coupling guiding hollow-core photonic crystal fibers. The fiber-core loading with iodine was undertaken at 10−1-10−2mbar vapor pressure using what, to the best of our knowledge, is a novel gas-manifold based on metallic vacuum parts with ceramic coated inner surfaces for corrosion resistance. The fiber is then sealed on the tips and mounted on FC/APC connectors for better integration with standard fiber components. The stand-alone microcells display Doppler lines with contrasts up to 73% in the 633 nm wavelength range, and an off-resonance insertion loss between 3 to 4 dB. Sub-Doppler spectroscopy based on saturable absorption has been carried out to resolve the hyperfine structure of the P(33)6-3 lines at room temperature with a full-width at half maximum of 24 MHz on the b4 component with the help of lock-in amplification. Also, we demonstrate distinguishable hyperfine components on the R(39)6-3 line at room temperature without any recourse to signal-to-noise ratio amplification techniques.
Optical scintillation in a maritime environment
Authors: Rabinovich W. S. , Mahon R. , Ferraro M. S.
Published: February 2023

Free space optical propagation affects many application areas, including communication, LIDAR, and directed energy. Optical turbulence causes dynamic changes in the propagated beam that can impact these applications. A primary measure of these effects is the optical scintillation index. In this work, we report on a comparison of experimental measurements of optical scintillation, conducted on a 16 km range across the Chesapeake Bay over a period of three months, to model predictions. Models for turbulence parameters were based on NAVSLaM, a Monin Obhukov similarity theory, and used environmental measurements taken on the range simultaneously with the scintillation measurements. These parameters were then used in two different classes of optical scintillation models: Extended Rytov theory, and wave optic simulation. We show that wave optics simulation matched the data much better than Extended Rytov theory, and that prediction of scintillation using environmental parameters is possible. In addition, we show that optical scintillation over water has different characteristics in stable versus unstable conditions.
Layout pattern analysis and coverage evaluation in computational lithography
Authors: Feng Yaobin , Song Zhiyang , Liu Jiaman , Li Zhiqin , Yang Feng , Jiang Hao , Liu Shiyuan
Published: February 2023

In advanced semiconductor technology nodes, the model accuracy of optical proximity correction (OPC) is the key for integrated circuit (IC) chip mask tape out, yield ramp up, and product time-to-market. An accurate model means a small prediction error for the full chip layout. As the full chip layout usually has large pattern variety, an optimal pattern set with good coverage is desired during the model calibration process. Currently, no existing solutions can provide the effective metrics to evaluate the coverage sufficiency of the selected pattern set before a real mask tape out, which may potentially cause higher re-tape out cost and product time-to-market delay due to the multiple rounds of model calibration. In this paper, we construct the metrics to evaluate the pattern coverage before any metrology data is obtained. The metrics are based on either the pattern’s intrinsic, numerical feature representation, or its potential model simulation behavior. Experimental results show a positive correlation between these metrics and lithographic model accuracy. An incremental selection method is also proposed based on the pattern simulation error. It reduces up to 53% of the model’s verification error range. These pattern coverage evaluation methods can improve the efficiency of OPC model building, and are, in turn, beneficial to the whole OPC recipe development process.
Switchable optical ring lattice in free space
Authors: Xu Da , Qi Tong , Chen Yizhe , Gao Wei
Published: February 2023

Optical lattices with spatially regular structures have recently attracted considerable attention across physics and optics communities. In particular, due to the increasing emergence of new structured light fields, diverse lattices with rich topology are being generated via multi-beam interference. Here, we report a specific ring lattice with radial lobe structures generated via superposition of two ring Airy vortex beams (RAVBs). We show that the lattice morphology evolves upon propagation in free space, switching from a bright-ring lattice to dark-ring lattice and even to fascinating multilayer texture. This underlying physical mechanism is related to the variation of the unique intermodal phase between the RAVBs as well as topological energy flow with symmetry breaking. Our finds provide an approach for engineering customized ring lattices to inspire a wide variety of new applications.
Measuring red blood cell shape in the human retina
Authors: Bedggood Phillip , Ding Yifu , Metha Andrew
Published: February 2023

The free diameter of a red blood cell generally exceeds the lumen diameter of capillaries in the central nervous system, requiring significant cellular deformation. However, the deformations undertaken are not well established under natural conditions due to the difficulty in observing corpuscular flow in vivo. Here we describe a novel, to the best of our knowledge, method to noninvasively study the shape of red blood cells as they traverse the narrow capillary networks of the living human retina, using high-speed adaptive optics. One hundred and twenty-three capillary vessels were analyzed in three healthy subjects. For each capillary, image data were motion-compensated and then averaged over time to reveal the appearance of the blood column. Data from hundreds of red blood cells were used to profile the average cell in each vessel. Diverse cellular geometries were observed across lumens ranging from 3.2 to 8.4 µm in diameter. As capillaries narrowed, cells transitioned from rounder to more elongated shapes and from being counter-aligned to aligned with the axis of flow. Remarkably, in many vessels the red blood cells maintained an oblique orientation relative to the axis of flow.
Feeding ecology of broadbill swordfish (Xiphias gladius) in the California current
Authors: Preti Antonella , Stohs Stephen M. , DiNardo Gerard T. , Saavedra Camilo , MacKenzie Ken , Noble Leslie R. , Jones Catherine S. , Pierce Graham J.
Published: February 2023

The feeding ecology of broadbill swordfish (Xiphias gladius) in the California Current was described based on analysis of stomach contents collected by fishery observers aboard commercial drift gillnet boats from 2007 to 2014. Prey were identified to the lowest taxonomic level and diet composition was analyzed using univariate and multivariate methods. Of 299 swordfish sampled (74 to 245 cm eye-to-fork length), 292 non-empty stomachs contained remains from 60 prey taxa. Genetic analyses were used to identify prey that could not be identified visually. Diet consisted mainly of cephalopods but also included epipelagic and mesopelagic teleosts. Jumbo squid (Dosidicus gigas) and Gonatopsis borealis were the most important prey based on the geometric index of importance. Swordfish diet varied with body size, location and year. Jumbo squid, Gonatus spp. and Pacific hake (Merluccius productus) were more important for larger swordfish, reflecting the ability of larger specimens to catch large prey. Jumbo squid, Gonatus spp. and market squid (Doryteuthis opalescens) were more important in inshore waters, while G. borealis and Pacific hake predominated offshore. Jumbo squid was more important in 2007–2010 than in 2011–2014, with Pacific hake being the most important prey item in the latter period. Diet variation by area and year probably reflects differences in swordfish preference, prey availability, prey distribution, and prey abundance. The range expansion of jumbo squid that occurred during the first decade of this century may particularly explain their prominence in swordfish diet during 2007–2010. Some factors (swordfish size, area, time period, sea surface temperature) that may influence dietary variation in swordfish were identified. Standardizing methods could make future studies more comparable for conservation monitoring purposes.
Regression shrinkage and selection via least quantile shrinkage and selection operator
Authors: Daneshvar Alireza , Mousa Golalizadeh
Published: February 2023

Over recent years, the state-of-the-art lasso and adaptive lasso have aquired remarkable consideration. Unlike the lasso technique, adaptive lasso welcomes the variables’ effects in penalty meanwhile specifying adaptive weights to penalize coefficients in a different manner. However, if the initial values presumed for the coefficients are less than one, the corresponding weights would be relatively large, leading to an increase in bias. To dominate such an impediment, a new class of weighted lasso will be introduced that employs all aspects of data. That is to say, signs and magnitudes of the initial coefficients will be taken into account simultaneously for proposing appropriate weights. To allocate a particular form to the suggested penalty, the new method will be nominated as ‘lqsso’, standing for the least quantile shrinkage and selection operator. In this paper, we demonstate that lqsso encompasses the oracle properties under certain mild conditions and delineate an efficient algorithm for the computation purpose. Simulation studies reveal the predominance of our proposed methodology when compared with other lasso methods from various aspects, particularly in ultra high-dimensional condition. Application of the proposed method is further underlined with real-world problem based on the rat eye dataset.
Using a substitute species to inform translocation of an endangered territorial mammal
Authors: Morandini Marina , Koprowski John L.
Published: February 2023

Substitute species can inform management strategies without exposing endangered species to unacceptable risk. Furthermore, experimental approaches may help to identify the causes of translocation failures, improving the chances of success. We used a surrogate subspecies,Tamiasciurus fremonti fremontito test different translocation techniques to inform on potential management actions with regards to the endangered Mt. Graham red squirrel (Tamiasciurus fremonti grahamensis). Individuals of both subspecies defend year-round territories in similar mixed conifer forests at elevations between 2650–2750 m, where they store cones to survive over winter. We fitted VHF radio collars to 54 animals, and we monitored their survival and movements until individuals settled on a new territory. We considered the effect of season, translocation technique (soft or hard release), and body mass on survival, distance moved after release, and time to settlement of translocated animals. Survival probability averaged 0.48 after 60 days from the translocation event and was not affected by season or translocation technique. 54% of the mortality was caused by predation. Distance moved and number of days to settlement varied with season, where winter was characterized by shorter distances (average of 364 m in winter versus 1752 m in fall) and a smaller number of days (6 in winter versus 23 in fall). The data emphasized on the potential of substitute species to provide valuable information for possible outcomes of management strategies to closely related endangered species.
Cancer detection for small-size and ambiguous tumors based on semantic FPN and transformer
Authors: He Jingzhen , Wang Jing , Han Zeyu , Li Baojun , Lv Mei , Shi Yunfeng
Published: February 2023

Early detection of tumors has great significance for formative detection and determination of treatment plans. However, cancer detection remains a challenging task due to the interference of diseased tissue, the diversity of mass scales, and the ambiguity of tumor boundaries. It is difficult to extract the features of small-sized tumors and tumor boundaries, so semantic information of high-level feature maps is needed to enrich the regional features and local attention features of tumors. To solve the problems of small tumor objects and lack of contextual features, this paper proposes a novel Semantic Pyramid Network with a Transformer Self-attention, named SPN-TS, for tumor detection. Specifically, the paper first designs a new Feature Pyramid Network in the feature extraction stage. It changes the traditional cross-layer connection scheme and focuses on enriching the features of small-sized tumor regions. Then, we introduce the transformer attention mechanism into the framework to learn the local feature of tumor boundaries. Extensive experimental evaluations were performed on the publicly available CBIS-DDSM dataset, which is a Curated Breast Imaging Subset of the Digital Database for Screening Mammography. The proposed method achieved better performance in these models, achieving 93.26% sensitivity, 95.26% specificity, 96.78% accuracy, and 87.27% Matthews Correlation Coefficient (MCC) value, respectively. The method can achieve the best detection performance by effectively solving the difficulties of small objects and boundaries ambiguity. The algorithm can further promote the detection of other diseases in the future, and also provide algorithmic references for the general object detection field.
FHbp variants among meningococci of serogroup B in Italy: Evolution and selective pressure, 2014–2017
Authors: Lo Presti Alessandra , Carannante Anna , Fazio Cecilia , Neri Arianna , Vacca Paola , Ambrosio Luigina , Lista Florigio , Fillo Silvia , Stefanelli Paola
Published: February 2023

Background

Neisseria meningitidis (meningococcus) is the causative agent of invasive meningococcal disease (IMD). Meningococcus of serogroup B (MenB) is one of the main serogroup causing IMD. MenB strains may be prevented by meningococcal B vaccines. In particular, vaccines with Factor H-binding protein (FHbp), classified into two subfamilies (A or B) or in three variants (v1, v2 or v3), are those available. The objective of the study was to investigate the phylogenetic relationships of FHbp subfamilies A and B (variants v1, v2 or v3) genes and proteins, together with their evolution patterns and selective pressure.

Materials and methods

Overall, alignments of FHbp nucleotide and protein sequence from 155 MenB samples collected in different parts of Italy, from 2014 to 2017, were analyzed by ClustalW. JModeltest and the Smart Model Selection software were used for the statistical selection of the best-fit substitution models for nucleotide and protein alignments. Site-specific positive and negative selection were estimated through the HYPHY package. The phylogenetic signal was investigated with the likelihood mapping method. The Maximum Likelihood (ML) phylogenetic reconstructions were performed with Phyml.

Results

The phylogenic analysis identified different clusters within the FHbp subfamily A and B variants, confirming sequence diversity. The pattern of selective pressure in our study indicated that subfamily B FHbp sequences are subjected to greater variations and positive selective pressure respect to subfamily A, with 16 positively supported selected sites identified.

Conclusion

The study pointed out the need for continued genomic surveillance for meningococci to monitor selective pressure and amino acidic changes. Monitoring the genetic diversity and molecular evolution of FHbp variants may be useful to investigate genetic diversity which may emerge over time.
Experimental investigation of the creep damage evolution of coal rock around gas extraction boreholes at different water contents
Authors: Guo Jiangbo , Zhang Tianjun , Pan Hongyu , Wu Jinyu
Published: February 2023

The creep process of the coal rock around the extraction boreholes under stress-water coupling is an important factor affecting the stability of the boreholes. To study the influence of the water content of perimeter of the coal rock around the boreholes on its creep damage, a creep intrinsic model considering water damage was established by introducing the plastic element model from the Nishihara model. To study the steady-state strain and damage evolution of coal rocks containing pores, and verify the practicality of the model, a graded loading water-bearing creep test was designed to explore the role of different water-bearing conditions in the creep process. The following conclusions were obtained: 1) water has a physical erosion and softening water wedge effect on the perimeter of the coal rock around the boreholes, which affects the loading axial strain and displacement of the perforated specimens; 2) an increase in water content reduces the time taken for perforated specimens to enter the creep phase, making the accelerated creep phase come earlier; 3) the parameters of the water damage model are considered to be exponentially related with the water content. The experimental data are similar to the results of the model parameters, and the model shows some practicality; 4) the damage variables in the accelerated creep phase increase rapidly throughout the creep process, leading to local instability in the borehole. The findings of the study provide important theoretical implications for the study of instability in gas extraction boreholes.
Spatial pattern and determinants of institutional delivery in Ethiopia: Spatial and multilevel analysis using 2019 Ethiopian demographic and health survey
Authors: Awol Mukemil , Edosa Dejene , Jemal Kemal
Published: February 2023

Background

In Ethiopia, despite the progress that has been made to improve maternal and child health, the proportion of births occurring at health institutions is still very low (26%), Which significantly contribute to a large number of maternal death 412 deaths/100,000 live births. Therefore, this study intended to determine spatial pattern and factors affecting institutional delivery among women who had live birth in Ethiopia within five years preceding survey.

Method

Data from 2019 Ethiopian demographic and health survey were used. Taking into account the nested structure of the data, multilevel logistic regression analysis has been employed to a nationally representative sample of 5753 women nested with in 305 communities/clusters.

Result

A significant heterogeneity was observed between clusters for institutional delivery which explains about 57% of the total variation. Individual-level variables: primary education (OR = 1.8: 95% CI: 1.44–2.26), secondary education (OR = 3.65: 95% CI: 2.19–6.1), diploma and higher (OR = 2.74: 95% CI: 1.02–7.34), women who had both Radio and Television were 4.6 times (OR = 4.6; 95% CI: 2.52, 8.45), four and above Antenatal visit (AOR = 2.72, 95% CI:2.2, 3.34), rich wealth index (OR = 2.22; 95% CI: 1.62–2.99), birth interval for 18 to 33 months (OR = 1.8; 95% CI: 1.19, 2.92), and women who space birth for 33 and above months (OR = 2.02; 95% CI: 1.3, 3.12) were associated with institutional delivery. Community level variables, community high proportion of antenatal visit (OR = 4.68; 95% CI: 4.13–5.30), and Region were associated with institutional delivery.

Conclusion

A clustered pattern of areas with low institutional delivery was observed in Ethiopia. Both individual and community level factors found significantly associated with institutional delivery theses showed the need for community women education through health extension programs and community health workers. And the effort to promote institutional delivery should pay special attention to antenatal care, less educated women and interventions considering awareness, access, and availability of the services are vital for regions. A preprint has previously been published.
Microbiological diagnosis and mortality of tuberculosis meningitis: Systematic review and meta-analysis
Authors: Seid Getachew , Alemu Ayinalem , Dagne Biniyam , Gamtesa Dinka Fekadu
Published: February 2023

Background

Tuberculosis (TB) which is caused by Mycobacterium tuberculosis poses a significant public health global treat. Tuberculosis meningitis (TBM) accounts for approximately 1% of all active TB cases. The diagnosis of Tuberculosis meningitis is notably difficult due to its rapid onset, nonspecific symptoms, and the difficulty of detecting Mycobacterium tuberculosis in cerebrospinal fluid (CSF). In 2019, 78,200 adults died of TB meningitis. This study aimed to assess the microbiological diagnosis TB meningitis using CSF and estimated the risk of death from TBM.

Methods

Relevant electronic databases and gray literature sources were searched for studies that reported presumed TBM patients. The quality of included studies was assessed using the Joanna Briggs Institute Critical Appraisal tools designed for prevalence studies. Data were summarized using Microsoft excel ver 16. The proportion of culture confirmed TBM, prevalence of drug resistance and risk of death were calculated using the random-effect model. Stata version 16.0 was used perform the statistical analysis. Moreover, subgroup analysis was conducted.

Results

After systematic searching and quality assessment, 31 studies were included in the final analysis. Ninety percent of the included studies were retrospective studies in design. The overall pooled estimates of CSF culture positive TBM was 29.72% (95% CI; 21.42–38.02). The pooled prevalence of MDR-TB among culture positive TBM cases was 5.19% (95% CI; 3.12–7.25). While, the proportion of INH mono-resistance was 9.37% (95% CI; 7.03–11.71). The pooled estimate of case fatality rate among confirmed TBM cases was 20.42% (95%CI; 14.81–26.03). Based on sub group analysis, the pooled case fatality rate among HIV positive and HIV negative TBM individuals was 53.39% (95%CI; 40.55–66.24) and 21.65% (95%CI;4.27–39.03) respectively.

Conclusion

Definite diagnosis of TBM still remains global treat. Microbiological confirmation of TBM is not always achievable. Early microbiological confirmation of TBM has great importance to reduce mortality. There was high rate of MDR-TB among confirmed TBM patients. All TB meningitis isolates should be cultured and drug susceptibility tested using standard techniques.
Spatio-temporal and transmission dynamics of sarcoptic mange in an endangered New World kit fox
Authors: Foley Patrick , Foley Janet , Rudd Jaime , Clifford Deana , Westall Tory , Cypher Brian
Published: February 2023

Sarcoptic mange poses a serious conservation threat to endangered San Joaquin kit foxes (Vulpes macrotis mutica). After first appearing in Bakersfield, California in spring 2013, mange reduced the kit fox population approximately 50% until the epidemic ended with minimally detectable endemic cases after 2020. Mange is lethal and thus, with such a high force of infection and lack of immunity, it remains unclear why the epidemic did not burn itself out rapidly and how it persisted so long. Here we explored spatio-temporal patterns of the epidemic, analyzed historical movement data, and created a compartment metapopulation model (named “metaseir”)to evaluate whether movement of foxes among patches and spatial heterogeneity would reproduce the eight years epidemic with 50% population reduction observed in Bakersfield. Our main findings frommetaseirwere that: 1) a simple metapopulation model can capture the Bakersfield-like disease epidemic dynamics even when there is no environmental reservoir or external spillover host, 2) the most impactful parameter on persistence and magnitude of the epidemic is the projection, β/αβ(transmission over decay rate of transmission over space), 3) heterogeneity in patch carrying capacities changes the critical value of the projection needed to achieve an epidemic but makes little difference to epidemic persistence time, and 4) the epidemic is relatively insensitive to birth rates and density vs. frequency-dependent transmission. Our model can help guide management and assessment of metapopulation viability of this vulpid subspecies, while the exploratory data analysis and model will also be valuable to understand mange in other, particularly den-occupying, species.
Temporal changes in the systemic concentrations of retinoids in pregnant and postpartum women
Authors: Jeong Hyunyoung , Armstrong Abigail T. , Isoherranen Nina , Czuba Lindsay , Yang Amy , Zumpf Katelynn , Ciolino Jody , Torres Elizabeth , Stika Catherine S. , Wisner Katherine L.
Published: February 2023

Retinoids and vitamin A are essential for multiple biological functions, including vision and immune responses, as well as the development of an embryo during pregnancy. Despite its importance, alterations in retinoid homeostasis during normal human pregnancy are incompletely understood. We aimed to characterize the temporal changes in the systemic retinoid concentrations across pregnancy and postpartum period. Monthly blood samples were collected from twenty healthy pregnant women, and plasma concentrations of retinol, all-trans-retinoic acid (atRA), 13-cis-retinoic acid (13cisRA), and 4-oxo-retinoic acids were measured using liquid chromatography-tandem mass spectrometry. Significant decreases in 13cisRA concentrations over the pregnancy were observed, with rebound increases in retinol and 13cisRA levels after delivery. Of note,atRA concentrations exhibited a unique temporal pattern with levels peaking at mid-pregnancy. While the 4-oxo-atRA concentration was below the limit of quantification, 4-oxo-13cisRA was readily detectable, and its temporal change mimicked that of 13cisRA. The time profiles ofatRA and 13cisRA remained similar after correction by albumin levels for plasma volume expansion adjustment. Together, the comprehensive profiling of systemic retinoid concentrations over the course of pregnancy provides insights into pregnancy-mediated changes in retinoid disposition to maintain its homeostasis.
Implementing social interventions in primary care in Canada: A qualitative exploration of lessons learned from leaders in the field
Authors: Bloch Gary , Rozmovits Linda
Published: February 2023

Purpose

Primary health care providers and practices are increasingly instituting direct interventions into social determinants of health and health inequities, but experiences of the leaders in these initiatives remain largely unexamined.

Methods

Sixteen semi-structured interviews with Canadian primary care leaders in developing and implementing social interventions were conducted to assess barriers, keys to success, and lessons learned from their work.

Results

Participants focused on practical approaches to establishing and maintaining social intervention programs and our analysis pointed to six major themes. A deep understanding of community needs, through data and client stories, forms a foundation for program development. Improving access to care is essential to ensuring programs reach those most marginalized. Client care spaces must be made safe as a first step to engagement. Intervention programs are strengthened by the involvement of patients, community members, health team staff, and partner agencies in their design. The impact and sustainability of these programs is enhanced by implementation partnerships with community members, community organizations, health team members, and government. Health providers and teams are more likely to assimilate simple, practical tools into practice. Finally, institutional change is key to establishing successful programs.

Conclusion

Creativity, persistence, partnership, a deep understanding of community and individual social needs, and a willingness to overcome barriers underlie the implementation of successful social intervention programs in primary health care settings.
Short-term association between ambient air pollution and cardio-respiratory mortality in Rio de Janeiro, Brazil
Authors: Cortes Taísa Rodrigues , Silveira Ismael Henrique , de Oliveira Beatriz Fátima Alves , Bell Michelle L. , Junger Washington Leite
Published: February 2023

Background

Several epidemiological studies have reported associations between ambient air pollution and mortality. However, relatively few studies have investigated this relationship in Brazil using individual-level data.

Objectives

To estimate the short-term association between exposure to particulate matter <10 μm (PM10) and ozone (O3), and cardiovascular and respiratory mortality in Rio de Janeiro, Brazil, between 2012 and 2017.

Methods

We used a time-stratified case-crossover study design with individual-level mortality data. Our sample included 76,798 deaths from cardiovascular diseases and 36,071 deaths from respiratory diseases. Individual exposure to air pollutants was estimated by the inverse distance weighting method. We used data from seven monitoring stations for PM10 (24-hour mean), eight stations for O3 (8-hour max), 13 stations for air temperature (24-hour mean), and 12 humidity stations (24-hour mean). We estimated the mortality effects of PM10 and O3 over a 3-day lag using conditional logistic regression models combined with distributed lag non-linear models. The models were adjusted for daily mean temperature and daily mean absolute humidity. Effect estimates were presented as odds ratios (OR) with their 95% confidence interval (CI) associated with a 10 μg/m3 increase in each pollutant exposure.

Results

No consistent associations were observed for both pollutant and mortality outcome. The cumulative OR of PM10 exposure was 1.01 (95% CI 0.99–1.02) for respiratory mortality and 1.00 (95% CI 0.99–1.01) for cardiovascular mortality. For O3 exposure, we also found no evidence of increased mortality for cardiovascular (OR 1.01, 95% CI 1.00–1.01) or respiratory diseases (OR 0.99, 95% CI 0.98–1.00). Our findings were similar across age and gender subgroups, and different model specifications.

Conclusion

We found no consistent associations between the PM10 and O3 concentrations observed in our study and cardio-respiratory mortality. Future studies need to explore more refined exposure assessment methods to improve health risk estimates and the planning and evaluation of public health and environmental policies.
Doing more with less: The use of non-invasive ventilatory support in a resource-limited setting
Authors: Buys Heloise , Kerbelker Tamara , Naidoo Shirani , Mukuddem-Sablay Zakira , Nxumalo Zanele , Muloiwa Rudzani
Published: February 2023

Objectives

Bubble CPAP (bCPAP), a non-invasive ventilation modality, has emerged as an intervention that is able to reduce pneumonia-related mortality in children in low resourced settings. Our study primarily aimed to describe a cohort of children who were started on CPAP in the Medical Emergency Unit (MEU) of Red Cross War Memorial Children’s Hospital 2016–2018.

Methods

A retrospective review of a randomly selected sample of paper-based folders was conducted. Children started on bCPAP at MEU were eligible for inclusion. Demographic and clinical data, management, and outcomes regarding admission to PICU, need for invasive ventilation and mortality were documented. Descriptive statistical data were generated for all relevant variables. Percentages depicted frequencies of categorical data while medians with interquartile ranges (IQR) were used to summarise continuous data.

Results

Of 500 children started on bCPAP, 266 (53%) were male; their median age was 3.7 (IQR 1.7–11.3) months and 169 (34%) were moderately to severely underweight-for-age. There were 12 (2%) HIV-infected children; 403 (81%) had received appropriate immunisations for their age; and 119 (24%) were exposed to tobacco smoke at home. The five most common primary reasons for admission were acute respiratory illness, acute gastroenteritis, congestive cardiac failure, sepsis and seizures. Most children, 409 (82%), had no underlying medical condition. Most children, 411 (82%), were managed in high care areas of the general medical wards while 126 (25%) went to PICU. The median time on CPAP was 1.7 (IQR 0.9–2.8) days. The median hospitalisation time was 6 (IQR 4–9) days. Overall, 38 (8%) children required invasive ventilatory support. Overall, 12 (2%) children with a median age of 7.5 (IQR 0.7–14.5) months died, six of whom had an underlying medical condition.

Conclusions

Seventy-five percent of children initiated on bCPAP did not require PICU admission. This form of non-invasive ventilatory support should be considered more widely in the context of limited access to paediatric intensive care units in other African settings.
Respiratory syncytial virus reinfections among infants and young children in the United States, 2011–2019
Authors: Nduaguba Sabina O. , Tran Phuong T. , Choi Yoonyoung , Winterstein Almut G.
Published: February 2023

Background

Although respiratory syncytial virus (RSV) immunoprophylaxis is recommended for high-risk infants, the American Academy of Pediatrics (AAP) recommends against immunoprophylaxis in the same season following a breakthrough hospitalization due to limited risk for a second hospitalization. Evidence in support of this recommendation is limited. We estimated population-based re-infection rates from 2011–2019 in children <5 years since RSV risk remains relatively high in this age group.

Materials and methods

Using claims data from private insurance enrollees, we established cohorts of children <5 years who were followed to ascertain annual (July 1-June 30) and seasonal (November 1- February 28/29) RSV recurrence estimates. Unique RSV episodes included inpatient encounters with RSV diagnosis ≥30 days apart, and outpatient encounters ≥30 days apart from each other as well as from inpatient encounters. The risk of annual and seasonal re-infection was calculated as the proportion of children with a subsequent RSV episode in the same RSV year/season.

Results

Over the 8 assessed seasons/years (N = 6,705,979) and across all age groups annual inpatient and outpatient infection rates were 0.14% and 1.29%, respectively. Among children with a first infection, annual inpatient and outpatient re-infection rates were 0.25% (95% confidence interval (CI) = 0.22–0.28) and 3.44% (95% CI = 3.33–3.56), respectively. Both infection and re-infection rates declined with age.

Conclusion

While medically-attended re-infections contributed numerically only a fraction of the total RSV infections, re-infections among those with previous infection in the same season were of similar magnitude as the general infection risk, suggesting that a previous infection may not attenuate the risk for a re-infection.
Glycolytic reprogramming is involved in tissue remodeling on chronic rhinosinusitis
Authors: Jo Min-Sik , Yang Hyun-Woo , Park Joo-Hoo , Shin Jae-Min , Park Il-Ho
Published: February 2023

Background

Glycolytic reprogramming is a key feature of chronic inflammatory disease. Extracellular matrix (ECM) produced by myofibroblasts plays an important role in tissue remodeling of nasal mucosa in chronic rhinosinusitis (CRS). This study aimed to determine whether glycolytic reprogramming contributes to myofibroblast differentiation and ECM production in nasal fibroblasts.

Methods

Primary nasal fibroblasts were isolated from the nasal mucosa of patients with CRS. Glycolytic reprogramming was assessed by measuring the extracellular acidification and oxygen consumption rates in nasal fibroblast, with and without transforming growth factor beta 1 (TGF-β1) treatment. Expression of glycolytic enzymes and ECM components was measured by real-time polymerase chain reaction, western blotting, and immunocytochemical staining. Gene set enrichment analysis was performed using whole RNA-sequencing data of nasal mucosa of healthy donors and patients with CRS.

Result

Glycolysis of nasal fibroblasts stimulated with TGF-B1 was upregulated along with glycolytic enzymes. Hypoxia-inducing factor (HIF)-1α was a high-level regulator of glycolysis, and increased HIF-1α expression promoted glycolysis of nasal fibroblasts, and inhibition of HIF-1α down-regulated myofibroblasts differentiation and ECM production.

Conclusion

This study suggests that inhibition of the glycolytic enzyme and HIF-1α in nasal fibroblasts regulates myofibroblast differentiation and ECM generation associated with nasal mucosa remodeling.