bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum Leptin in Hospitalized Community-Acquired Pneumonia Children under the Age of Five Years
Authors: Abouhussein Heba , Mohamed Shereen , Dougman Talal , ElHawary Rabab
Published: March 2020

Background

Community-acquired pneumonia (CAP) accounts for 19% of the world’s total deaths among all age groups yearly, with highest rates in children less than 5 years. This study is designed to evaluate the serum leptin level in hospitalized children under the age of 5 years with CAP.

Results

This prospective cross-sectional study included CAP children under the age of 5 years. Forty-one patients admitted to pediatric intensive care unit (PICU) and 41 patients admitted to general ward were enrolled. Patients with any other cause that may elevate serum leptin were excluded. Serum leptin was measured on the day of admission. The PICU patients had a significantly higher median serum leptin than that of the ward patients (p < 0.001). C-reactive protein (CRP) level was significantly higher in patients with elevated serum leptin than in patients with normal serum leptin (p = 0.001). There was a significant association between high serum leptin and positive sputum cultures (p < 0.001), particularly cultures growing more than one organism (p < 0.001). There was a positive, weak correlation between serum leptin and length of stay (r = 0.30, p = 0.007). Serum leptin showed good discrimination between PICU admissions and inpatient ward admissions (AUC = 0.777, p < 0.001); at a cut-off value of > 29.6 pg/ml, serum leptin had a sensitivity of 70.7% and a specificity of 87.8%

Conclusion

We may conclude that CAP patients with a serum leptin level above 29.6 pg/ml should be considered for PICU admission.
Executive Perspectives
Authors: Agnew Tom
Published: March 2020

Growing up in Colchester, England, Bob Brook knew one day he would be the CEO of an oil and gas company. Not really. Bob was just interested in taking risks and had a desire to travel and see the world. Armed with a mathematics degree from the University of East Anglia in Norwich, Bob signed on with Geophysical Service International (GSI), which took him to an office outside London where he began his career in geophysics.
Structured Psychological Support for people with personality disorder: feasibility randomised controlled trial of a low-intensity intervention
Authors: Crawford Mike J. , Thana Lavanya , Parker Jennie , Turner Oliver , Carney Aidan , McMurran Mary , Moran Paul , Weaver Timothy , Barrett Barbara , Roberts Sarah , Claringbold Amy , Bassett Paul , Sanatinia Rahil , Spong Amanda
Published: March 2020

Background

National guidance cautions against low-intensity interventions for people with personality disorder, but evidence from trials is lacking.

Aims

To test the feasibility of conducting a randomised trial of a low-intensity intervention for people with personality disorder.

Method

Single-blind, feasibility trial (trial registration: ISRCTN14994755). We recruited people aged 18 or over with a clinical diagnosis of personality disorder from mental health services, excluding those with a coexisting organic or psychotic mental disorder. We randomly allocated participants via a remote system on a 1:1 ratio to six to ten sessions of Structured Psychological Support (SPS) or to treatment as usual. We assessed social functioning, mental health, health-related quality of life, satisfaction with care and resource use and costs at baseline and 24 weeks after randomisation.

Results

A total of 63 participants were randomly assigned to either SPS (n = 33) or treatment as usual (n = 30). Twenty-nine (88%) of those in the active arm of the trial received one or more session (median 7). Among 46 (73%) who were followed up at 24 weeks, social dysfunction was lower (−6.3, 95% CI −12.0 to −0.6, P = 0.03) and satisfaction with care was higher (6.5, 95% CI 2.5 to 10.4; P = 0.002) in those allocated to SPS. Statistically significant differences were not found in other outcomes. The cost of the intervention was low and total costs over 24 weeks were similar in both groups.

Conclusions

SPS may provide an effective low-intensity intervention for people with personality disorder and should be tested in fully powered clinical trials.
Differential Frequency of CYP2R1 Variants Across Populations Reveals Pathway Selection for Vitamin D Homeostasis
Authors: Casella Alex , Long Caela , Zhou Jingman , Lai Meizan , O’Lear Lauren , Caplan Ilana , Levine Michael A , Roizen Jeffrey D
Published: March 2020

Context

Normal vitamin D homeostasis is necessary to ensure optimal mineral metabolism. Dietary insufficiency of vitamin D and the lack of sunlight each have well understood roles in vitamin D deficiency; however, the extent to which common genetic variations in vitamin D metabolizing enzymes contribute to alterations in vitamin D homeostasis remains uncertain.

Objective

To examine the possibility that common coding variation in vitamin D metabolizing enzymes alters vitamin D homeostasis we determined the effect of 44 nonsynonymous polymorphisms in CYP2R1, the vitamin D 25-hydroxylase, on enzyme function.

Results

Twenty-one of these polymorphisms decreased activity, while 2 variants increased activity. The frequency of CYP2R1 alleles with decreased 25-hydroxylase activity is 3 in every 1000 Caucasians and 7 in every 1000 African Americans. In populations where exposure to sunlight is high, alleles with decreased function occur at a frequency as high as 8%. The pattern of selected variation as compared to nonselected variation is consistent with it being the result of positive selection for nonfunctional alleles closer to the equator. To examine this possibility, we examined the variation pattern in another protein in the vitamin D pathway, the vitamin D binding protein (GC protein). The pattern of selected variation in the GC protein as compared to nonselected variation is also consistent with it being the result of positive selection for nonfunctional alleles closer to the equator.

Conclusions

CYP2R1 polymorphisms have important effects on vitamin D homeostasis, and the geographic variability of CYP2R1 alleles represents an adaptation to differential exposures to UVB irradiation from sunlight.
Serum Androgens Are Independent Predictors of Insulin Clearance but Not of Insulin Secretion in Women With PCOS
Authors: Tosi Flavia , Dal Molin Francesca , Zamboni Federica , Saggiorato Enrica , Salvagno Gian Luca , Fiers Tom , Kaufman Jean-Marc , Bonora Enzo , Moghetti Paolo
Published: March 2020

Context/Objective

In insulin-resistant individuals, hyperinsulinemia is a key compensatory mechanism, aimed at maintaining glucose homeostasis. Increased secretion and reduced clearance of insulin may both potentially contribute to this phenomenon. Insulin resistance and hyperinsulinemia are common findings in women with polycystic ovary syndrome (PCOS). While there is some information on insulin secretion, very few studies have investigated metabolic clearance rate of insulin (MCRI) in these women. Moreover, there is paucity of data on the relationships between MCRI and the pathophysiological characteristics of PCOS. The aim of the study was to explore these issues.

Patients

One hundred ninety women with PCOS, diagnosed according to the Rotterdam criteria, with normal glucose tolerance.

Design

Assessment of MCRI and clinical, hormonal, and metabolic characteristics of subjects. MCRI and insulin sensitivity were measured by the hyperinsulinemic euglycemic clamp. Serum androgens were assessed by liquid chromatography-mass spectrometry and equilibrium dialysis. A historical sample of healthy women was used to define the corresponding reference intervals.

Results

MCRI was impaired in about two-thirds of women with PCOS. Subjects with low MCRI differed from those with normal MCRI for a number of anthropometric, metabolic, and endocrine features. In multivariate analysis, the degree of adiposity, estimates of insulin secretion, and serum androgen concentrations were independent predictors of MCRI. Conversely, age, adiposity, MCRI, and insulin sensitivity, but not serum androgens, were independent predictors of insulin secretion.

Conclusions

In women with PCOS, metabolic clearance of insulin is reduced, contributing to generating hyperinsulinemia. Serum androgens are independent predictors of this phenomenon.
Recharacterizing the Metabolic State of Energy Balance in Thrifty and Spendthrift Phenotypes
Authors: Hollstein Tim , Basolo Alessio , Ando Takafumi , Votruba Susanne B , Walter Mary , Krakoff Jonathan , Piaggi Paolo
Published: March 2020

Purpose

The human thrifty phenotype hypothesis presupposes that lower 24-hour (24h) energy expenditure (24EE) during famine preserves body mass and promotes survival. The prevailing view defines thrifty individuals as having a lower 24EE during fasting. However, it is also plausible that the greater decline in 24EE during fasting in thrifty individuals is due to higher 24EE during energy balance conditions (ENBAL). Herein, we provide evidence that this is indeed the case.

Methods

In 108 healthy subjects, 24EE was measured in a whole-room indirect calorimeter both during ENBAL and 24h fasting conditions. Subjects were categorized as thrifty or spendthrift based on the median value (−162 kcal/day) of the difference in 24EE (adjusted for body composition) between fasting and ENBAL conditions. Concomitant 24h urinary catecholamines were assessed by liquid chromatography–mass spectrometry.

Results

Compared to ENBAL, 24EE decreased during 24h fasting by 172 kcal/day (standard deviation = 93; range, −470 to 122). A greater-than-median decrease in 24EE (“thriftier” phenotype) was due to higher 24EE during ENBAL (+124 kcal/day; P < 0.0001) but not to lower 24EE during fasting (P = 0.35). Greater fasting-induced increase in epinephrine was associated with concomitant lower decrease in 24EE (r = 0.27; P = 0.006).

Main Conclusion

The greater decrease in 24EE during acute fasting (which characterizes the thrifty phenotype) is not due to reduced metabolic rate during fasting but to a relatively higher 24EE during feeding conditions, and this decrease in 24EE during fasting is accompanied by a smaller increase in epinephrine. These results recharacterize the prevailing view of the short-term 24EE responses that define the human metabolic phenotypes.

Clinical Trials: NCT00523627, NCT00687115, NCT02939404
Integration of luminal pressure and signalling in tissue self-organization
Authors: Chan Chii J. , Hiiragi Takashi
Published: March 2020

Many developmental processes involve the emergence of intercellular fluid-filled lumina. This process of luminogenesis results in a build up of hydrostatic pressure and signalling molecules in the lumen. However, the potential roles of lumina in cellular functions, tissue morphogenesis and patterning have yet to be fully explored. In this Review, we discuss recent findings that describe how pressurized fluid expansion can provide both mechanical and biochemical cues to influence cell proliferation, migration and differentiation. We also review emerging techniques that allow for precise quantification of fluid pressure in vivo and in situ. Finally, we discuss the intricate interplay between luminogenesis, tissue mechanics and signalling, which provide a new dimension for understanding the principles governing tissue self-organization in embryonic development.
Single-cyst transcriptome analysis of Drosophila male germline stem cell lineage
Authors: Shi Zhen , Lim Cindy , Tran Vuong , Cui Kairong , Zhao Keji , Chen Xin
Published: March 2020

The Drosophila male germline stem cell (GSC) lineage provides a great model to understand stem cell maintenance, proliferation, differentiation and dedifferentiation. Here, we use the Drosophila GSC lineage to systematically analyze the transcriptome of discrete but continuously differentiating germline cysts. We first isolated single cysts at each recognizable stage from wild-type testes, which were subsequently applied for RNA-seq analyses. Our data delineate a high-resolution transcriptome atlas in the entire male GSC lineage: the most dramatic switch occurs from early to late spermatocyte, followed by the change from the mitotic spermatogonia to early meiotic spermatocyte. By contrast, the transit-amplifying spermatogonia cysts display similar transcriptomes, suggesting common molecular features among these stages, which may underlie their similar behavior during both differentiation and dedifferentiation processes. Finally, distinct differentiating germ cell cyst samples do not exhibit obvious dosage compensation of X-chromosomal genes, even considering the paucity of X-chromosomal gene expression during meiosis, which is different from somatic cells. Together, our single cyst-resolution, genome-wide transcriptional profile analyses provide an unprecedented resource to understand many questions in both germ cell biology and stem cell biology fields.
Physical interactions between Gsx2 and Ascl1 balance progenitor expansion versus neurogenesis in the mouse lateral ganglionic eminence
Authors: Roychoudhury Kaushik , Salomone Joseph , Qin Shenyue , Cain Brittany , Adam Mike , Potter S. Steven , Nakafuku Masato , Gebelein Brian , Campbell Kenneth
Published: March 2020

The Gsx2 homeodomain transcription factor promotes neural progenitor identity in the lateral ganglionic eminence (LGE), despite upregulating the neurogenic factor Ascl1. How this balance in maturation is maintained is unclear. Here, we show that Gsx2 and Ascl1 are co-expressed in subapical progenitors that have unique transcriptional signatures in LGE ventricular zone (VZ) cells. Moreover, whereas Ascl1 misexpression promotes neurogenesis in dorsal telencephalic progenitors, the co-expression of Gsx2 with Ascl1 inhibits neurogenesis. Using luciferase assays, we found that Gsx2 reduces the ability of Ascl1 to activate gene expression in a dose-dependent and DNA binding-independent manner. Furthermore, Gsx2 physically interacts with the basic helix-loop-helix (bHLH) domain of Ascl1, and DNA-binding assays demonstrated that this interaction interferes with the ability of Ascl1 to bind DNA. Finally, we modified a proximity ligation assay for tissue sections and found that Ascl1-Gsx2 interactions are enriched within LGE VZ progenitors, whereas Ascl1-Tcf3 (E-protein) interactions predominate in the subventricular zone. Thus, Gsx2 contributes to the balance between progenitor maintenance and neurogenesis by physically interacting with Ascl1, interfering with its DNA binding and limiting neurogenesis within LGE progenitors.
Plakophilin 3 phosphorylation by ribosomal S6 kinases supports desmosome assembly
Authors: Müller Lisa , Rietscher Katrin , Keil René , Neuholz Marvin , Hatzfeld Mechthild
Published: March 2020

Desmosome remodeling is crucial for epidermal regeneration, differentiation and wound healing. It is mediated by adapting the composition, and by post-translational modifications, of constituent proteins. We have previously demonstrated in mouse suprabasal keratinocytes that plakophilin (PKP) 1 mediates strong adhesion, which is negatively regulated by insulin-like growth factor 1 (IGF1) signaling. The importance of PKP3 for epidermal adhesion is incompletely understood. Here, we identify a major role of epidermal growth factor (EGF), but not IGF1, signaling in PKP3 recruitment to the plasma membrane to facilitate desmosome assembly. We find that ribosomal S6 kinases (RSKs) associate with and phosphorylate PKP3, which promotes PKP3 association with desmosomes downstream of the EGF receptor. Knockdown of RSKs as well as mutation of an RSK phosphorylation site in PKP3 interfered with desmosome formation, maturation and adhesion. Our findings implicate a coordinate action of distinct growth factors in the control of adhesive properties of desmosomes through modulation of PKPs in a context-dependent manner.
The teleost fish intestine is a major oxalate-secreting epithelium
Authors: Whittamore Jonathan M.
Published: March 2020

Oxalate is a common constituent of kidney stones but the mechanism of its transport across epithelia are not well understood. With prior research on the role of the intestine focused on mammals this study considered oxalate handling by teleost fish. Given the osmotic challenge of seawater (SW), teleosts have limited scope for urinary oxalate excretion relative to freshwater (FW). The marine teleost intestine was hypothesized as the principal route for oxalate elimination thus demanding epithelial secretion. To test this, intestinal 14C-oxalate flux was compared between FW- and SW-acclimated sailfin molly (Poecilia latipinna). In SW, oxalate was secreted at remarkable rates (367.90±22.95 pmol cm−2 h−1) which were similar following FW transfer (387.59±27.82 pmol cm−2 h−1), implying no regulation by salinity. Nevertheless, this ability to secrete oxalate 15-19 times higher than mammalian small intestine supports this proposal of the teleost gut as a previously unrecognized excretory pathway.
Comparative evaluation of sensitivity and specificity of immunochromatography kit for the rapid detection of norovirus and rotavirus in Bangladesh
Authors: Shaha Modhusudon , Sifat Sadia Farzana , Mamun Md. Al , Billah Md. Baki , Sharif Nadim , Nobel Nasir Uddin , Parvez Anowar Khasru , Talukder Ali Azam , Nomura Akiko , Ushijima Hiroshi , Dey Shuvra Kanti
Published: March 2020

We report a comprehensive analysis of sensitivity and specificity of immunochromatography kit (IC Kit) for the rapid detection of norovirus and rotavirus in Bangladesh. The IC kit (IP-Noro/Rota) provides highest sensitivity (100%) to both viruses compared to the reference method reverse transcription- polymerase chain reaction (RT- PCR) for diagnosis. Furthermore, the test provides a high specificity of 98.9% and 88.5% to diagnose norovirus and rotavirus, respectively, as well as good agreement with the reference method. We also found high prevalence of rotavirus infection (74%) among Bangladeshi pediatric population, of which most of the patients were less than five years old, suffering from severe dehydration, abdominal pain and vomiting. This study is the first to report the ease and rapid detection of norovirus and rotavirus by IC kits in Bangladesh. Therefore, IP-Noro/Rota kit is recommended for the rapid detection of these viruses in routine diagnosis as well as during outbreaks.
Emerging Challenges of Teaching English in Non-native English-Speaking Countries: Teachers’ View
Authors: Hasanah Nurul , Utami Pratiwi Tri
Published: March 2020

Teaching English to students, particularly non-English speakers, requires proper strategies and methods. By doing so, each teacher has his/her challenges. This study intends to unveil the emerging challenges faced by English teachers from non-native English-speaking countries (non-NESCs) such as China, Japan, Thailand, Senegal, Mongolia, Cambodia, and Laos. This study stands on to answer two research questions: 1. What are the challenges of teaching English in non-native English-speaking countries? 2. Is there any effort to overcome the challenges? If so, how do they overcome it? By utilizing the qualitative method, seven teachers are interviewed to tell their challenges. The result indicates three main problems, including learning materials which do not cover students’ need, too big classroom size and school environment, and also students’ low motivation. Some programs are conducted to overcome those challenges. For example, Japan has an Assistant Language Teacher (ALT) who comes once a week to cooperate with the English teacher in each school. Then, Volunteer English Teacher (VET) program helps English Teachers in Laos.
Current solutions for the treatment of chronic articular cartilage defects in the knee
Authors: Chimutengwende-Gordon Mukai , Donaldson James , Bentley George
Published: March 2020

Chondral and osteochondral defects in the knee are common and may lead to degenerative joint disease if treated inappropriately. Conventional treatments such as microfracture often result in fibrocartilage formation and are associated with inferior results. Additionally, microfracture is generally unsuitable for the treatment of defects larger than 2–4 cm2. The osteochondral autograft transfer system (OATS) has been shown to produce superior clinical outcomes to microfracture but is technically difficult and may be associated with donor-site morbidity. Osteochondral allograft use is limited by graft availability and failure of cartilage incorporation is an issue. Autologous chondrocyte implantation (ACI) has been shown to result in repair with hyaline-like cartilage but involves a two-stage procedure and is relatively expensive. Rehabilitation after ACI takes 12 months, which is inconvenient and not feasible for athletic patients. Newer methods to regenerate cartilage include autologous stem cell transplantation, which may be performed as a single-stage procedure, can have a shorter rehabilitation period and is less expensive than ACI. Longer-term studies of these methods are needed.

Cite this article: EFORT Open Rev 2020;5:156-163. DOI: 10.1302/2058-5241.5.190031
Digital image correlation with improved efficiency by pixel selection
Authors: Shao Xinxing , Zhong Fuqiang , Huang Wei , Dai Xiangjun , Chen Zhenning , He Xiaoyuan
Published: March 2020

With the increase in digital image correlation (DIC) applications, the computational efficiency of DIC is becoming increasingly important. In previous studies, real-time DIC was realized with a relatively small subset. However, a small subset does not always include sufficient gray gradient information. In this paper, a pixel selection strategy is proposed to improve the computational efficiency of DIC further, allowing a real-time deformation measurement with a large subset. Within the subset, zero weight is assigned to unreliable pixels as a way of pursuing maximum efficiency. The modulus of the local intensity gradient vector of each pixel in the reference image is used as the criterion for reliability. Numerical and real experiments conducted to validate the feasibility and effectiveness of the strategy showed that the computational speed of DIC could be improved about 2 times.
Peripheral image quality in pseudophakic eyes
Authors: Togka Konstantina A. , Livir-Rallatos Angelos , Christaras Dimitrios , Tsoukalas Spyridon , Papasyfakis Nikolaos , Artal Pablo , Ginis Harilaos
Published: March 2020

The purpose of this work was to evaluate peripheral image quality in the pseudophakic eye using computational, physical, and psychophysical methods. We designed and constructed a physical model of the pseudophakic human eye with realistic dimensions using a corneal phantom and a board-only camera that was pivoted around an axis that matched the anatomical center of a human retina, assuming a radius of curvature of 12 mm, while it was submersed in a 23.4 mm long water filled chamber to emulate human ocular axial length. We used this optical setup to perform direct recording of the point spread function (PSF) and the associated retinal images for a commercial intraocular lens (IOL). Additionally, psychophysical tests were carried out to investigate the impact of the off-axis astigmatism in peripheral visual performance, where spectacle-induced astigmatism simulated the pseudophakic conditions in healthy subjects. Our findings using the physical eye model confirm the existence of large amounts of astigmatism in the periphery of the pseudophakic eye. The psychophysical tests revealed a significant reduction of detection sensitivity in the peripheral visual field. The latter suggests that off-axis astigmatism in patients implanted with IOLs may have performance and safety implications for activities requiring efficient peripheral vision.
Ghost polarimetry using Stokes correlations
Authors: Hannonen Antti , Hoenders Bernhard J. , Elsässer Wolfgang , Friberg Ari T. , Setälä Tero
Published: March 2020

We present here a novel ghost polarimeter based on Stokes parameter correlations and a spatially incoherent classical source with adjustable polarization state and Gaussian statistics. The setup enables extracting the four amplitudes and three phase differences related to the spectral

2
×
2

complex Jones matrix of any transmissive polarization-sensitive object. Our work extends the ghost imaging methods from the traditional intensity correlation measurements to the detection of polarization state correlations.
Quality estimation of non-demolition measurement with lossy atom-light hybrid interferometers
Authors: Fan D.-H. , Chen S.-Y. , Yu Z.-F. , Zhang Keye , Chen L. Q.
Published: March 2020

The atom-light hybrid interferometer recently attracted much attention in the research of precision metrology for its combination of light and atomic spin wave. With the AC Stark effect and proper design, it can be applied in the scheme of quantum non-demolition (QND) measurement of photon numbers. In this work, we apply the QND criteria to the scheme and theoretically derive its explicit formulas with various losses of the atomic-light hybrid interferometer. With the formulas and actual experiment parameters, we estimate and compare the performance of the vapor-atom-based and cold-atom-based hybrid interferometer in the QND measurement, analyze the influences of different kinds of losses, and provide optimized working parameter ranges of the interferometer.
Separation method of bending and torsion in shape sensing based on FBG sensors array
Authors: Yi Xinhua , Chen Xiangyan , Fan Hongchao , Shi Fei , Cheng Xiaomin , Qian Jinwu
Published: March 2020

This paper presents a theoretical method for separating bending and torsion of shape sensing sensor to improve sensing accuracy during its deformation. We design a kind of shape sensing sensor by encapsulating three fibers on the surface of a flexible rod and forming a triangular FBG sensors array. According to the configuration of FBG sensors array, we derive the relationship between bending curvature and bending strain, and set up a function about the packaging angle of FBG sensor and strain induced by torsion under different twist angles. Combined with the influence of bending and torsion on strain, we establish a nonlinear matrix equation resolving three unknown parameters including maximum strain, bending direction and wavelength shift induced by torsion and temperature. The three parameters are sufficient to separate bending and torsion, and acquire two scalar functions including curvature and torsion, which could describe 3D shape of rod according to Frenet-Serret formulas. Experimental results show that the relative average error of measurement about maximum strain, bending direction is respectively 2.65% and 0.86% when shape-sensing sensor is bent into an arc with a radius of 260 mm. The separating method also applied to 2D shape and 3D shape of reconstruction, and the absolute spatial position maximum error is respectively 3.79mm and 11.10mm when shape-sensing sensor with length 500mm is bent into arc shape with a radius 260mm and helical curve. The experiment results verify the feasibility of separating method, which would provide effective parameters for precise 3D reconstruction model of shape sensing sensor.
High-precision fiber Bragg gratings inscription by infrared femtosecond laser direct-writing method assisted with image recognition
Authors: Yu Yanjiang , Shi Jindan , Han Feng , Sun Wenjuan , Feng Xian
Published: March 2020

For achieving high efficiency fiber Bragg gratings (FBGs) utilizing infrared femtosecond laser point-by-point inscription method, it is crucial to make the inscribed periodic structure perfectly in phase. It requires a perfect alignment between the micrometer-sized laser spot with the fiber along the length. Here we report the highly precise fabrication of FBGs by infrared femtosecond laser point-by-point direct-writing method. Image recognition technique is applied to for automatically aligning the trace of the laser spot with the referenced central axis of the fiber along the whole FBG length. FBGs inscription with high spatial precision is confirmed by multiple approaches, including microscopic photographing and FBG spectroscopic measurement. 50 mm-long uniform FBGs with high reflectivity have been successfully demonstrated in a small-core single-mode silica fiber using auto-aligning technique.
High-peak-power eye-safe orthogonally-polarized dual-wavelength Nd:YLF/KGW Raman laser
Authors: Tu Zhi-Hua , Dai Shi-Bo , Chen Meng-Ting , Yin Hao , Zhu Si-Qi , Li Zhen , Ji Encai , Chen Zhen-Qiang
Published: March 2020

An actively Q-switched eye-safe orthogonally-polarized dual-wavelength intracavity Raman laser was demonstrated for the first time, to the best of our knowledge. The gain balanced dual-wavelength operation at 1314 and 1321 nm within an in-band pumped Nd:YLF laser was realized by slightly titling the cavity mirrors. Owing to the KGW bi-axial properties, two sets of simultaneous orthogonally-polarized dual-wavelength Raman lasers at 1470, 1490 nm and 1461, 1499 nm were achieved by simply rotating the KGW crystal for 90°, respectively. With an incident pump power of 30 W and an optimized pulse repetition frequency of 5 kHz, the maximum dual-wavelength Raman output powers of 2.6 and 2.4 W were obtained with the pulse widths of 5.8 and 6.3 ns, respectively, corresponding to the peak powers up to 89.7 and 76.5 kW.
Coaxial scanning holography
Authors: Kim Taegeun , Kim Taewoong
Published: March 2020

Optical scanning holography requires interference optics, which separates a laser beam into two paths and recombines the two path beams after being modulated spatially and temporarily. This requires high accuracy and stability of the apparatus with a highly coherent light source. In this Letter, we propose a coaxial scanning holography (CSH) capable of realizing scanning holography with high stability and low complexity by forming a scanning beam in a single optical path using a geometrical phase shift. An experimental verification of the CSH by optical acquisition and subsequent reconstruction of the hologram is reported.
High-speed SSB transmission with a silicon MZM and a soft combined artificial neural network-based equalization
Authors: Ming Hao , Zhang Lei , Yang Fan , Ruan Xiaoke , Zhang Fan
Published: March 2020

We experimentally demonstrate high-speed metro-scale optical transmission of a single sideband (SSB) 4-ary pulse amplitude modulation (PAM-4) signal based on a silicon photonic dual-drive Mach–Zehnder modulator (MZM). We propose a novel, to the best of our knowledge, artificial neural network (ANN) structure of soft combined ANN (SC-ANN) to compensate for both linear and nonlinear impairments of the signal. SC-ANN obtains the enhanced performance by averaging the outputs of conventional ANN with different sizes. With the help of the SC-ANN, we achieve a 320 km standard single-mode fiber (SSMF) transmission of 184 Gb/s (92Gbaud) PAM-4 with a bit-error rate (BER) below the 20% soft-decision forward error-correction (SD-FEC) threshold of

2.4

×

10

−
2

, and the optical signal-to-noise ratio (OSNR) penalty is only 0.3 dB compared to the back-to-back (BTB) results.
Kilowatt-level ytterbium-Raman fiber amplifier with a narrow-linewidth and near-diffraction-limited beam quality
Authors: Ma Pengfei , Miao Yu , Liu Wei , Meng Daren , Zhou Pu
Published: March 2020

By focusing on a typical emitting wavelength of 1120 nm as an example, we present the first, to the best of our knowledge, demonstration of a high-efficiency, narrow-linewidth kilowatt-level all-fiber amplifier based on hybrid ytterbium-Raman (Yb-Raman) gains. Notably, two temporally stable, phase-modulated single-frequency lasers operating at 1064 nm and 1120 nm, respectively, were applied in the fiber amplifier, to simultaneously alleviate the spectral broadening of the 1120 nm signal laser and suppress the stimulated Brillouin scattering effect. An over 1 kW narrow-linewidth 1120 nm signal laser was obtained with slope efficiency of

∼

77

%

and beam quality of

M

x
2

∼

1.25

,

M

y
2

∼

1.17

. The amplified spontaneous emission (ASE) noise in the fiber amplifier was effectively suppressed by incorporating an ASE-filtering system between the seed laser and the main amplifier. Furthermore, the experimental results demonstrate that the spectral linewidth broadening effect is tightly related to the injected power ratios between the two seed lasers. Overall, this setup could provide a reference on obtaining and optimizing high-power narrow-linewidth fiber lasers operating in the long wavelength extreme of the Yb gain spectrum.
Femtometer-resolved simultaneous measurement of multiple laser wavelengths in a speckle wavemeter
Authors: Bruce Graham D. , O’Donnell Laura , Chen Mingzhou , Facchin Morgan , Dholakia Kishan
Published: March 2020

Many areas of optical science require an accurate measurement of optical spectra. Devices based on laser speckle promise compact wavelength measurement, with attometer-level sensitivity demonstrated for single wavelength laser fields. The measurement of multimode spectra using this approach would be attractive, yet this is currently limited to picometer resolution. Here, we present a method to improve the resolution and precision of speckle-based multi-wavelength measurements. We measure multiple wavelengths simultaneously, in a device comprising a single 1-m-long step-index multimode fiber and a fast camera. Independent wavelengths separated by as little as 1 fm are retrieved with 0.2 fm precision using principal component analysis. The method offers a viable way to measure sparse spectra containing multiple individual lines and may find application in the tracking of multiple lasers in fields such as quantum technologies and optical telecommunications.
High pulse energy and quantum efficiency mid-infrared gas Raman fiber laser targeting CO2 absorption at 4.2  µm
Authors: Wang Yazhou , Dasa Manoj K. , Adamu Abubakar I. , Antonio-Lopez J. E. , Habib Md. Selim , Amezcua-Correa Rodrigo , Bang Ole , Markos Christos
Published: March 2020

In this Letter, we demonstrate a high pulse energy and linearly polarized mid-infrared Raman fiber laser targeting the strongest absorption line of

C
O

2

at

∼

4.2

µ

m

. This laser was generated from a hydrogen (

H

2

)-filled antiresonant hollow-core fiber, pumped by a custom-made 1532.8 nm Er-doped fiber laser delivering 6.9 ns pulses and 11.6 kW peak power. A quantum efficiency as high as 74% was achieved, to yield 17.6 µJ pulse energy at 4.22 µm. Less than 20 bar

H

2

pressure was required to maximize the pulse energy since the transient Raman regime was efficiently suppressed by the long pump pulses.
280-km experimental demonstration of a quantum digital signature with one decoy state
Authors: Ding Hua-Jian , Chen Jing-Jing , Ji Liang , Zhou Xing-Yu , Zhang Chun-Hui , Zhang Chun-Mei , Wang Qin
Published: March 2020

A quantum digital signature (QDS) guarantees the unforgeability, nonrepudiation, and transferability of signature messages with information-theoretic security, and hence has attracted much attention recently. However, most previous implementations of QDS showed relatively low signature rates and/or short transmission distance. In this Letter, we report a proof-of-principle phase-encoding QDS demonstration using only one decoy state. First, such a method avoids the modulation of the vacuum state, thus reducing experimental complexity and random number consumption. Moreover, incorporated with low-loss asymmetric Mach–Zehnder interferometers and a real-time polarization calibration technique, we have successfully achieved a higher signature rate, e.g., 0.98 bit/s at 103 km, and to date, a record-breaking, to the best of our knowledge, transmission distance of over 280-km installed fibers. Our work represents a significant step towards real-world applications of QDS.
Democracia y movimientos sociales en América Latina
Authors: Paramio Ludolfo
Published: March 2020

RESUMEN: En el presente, en la ,fase de recuperación de la democracia en América Latina, el sistema político tiene dos alternativas frente a los movimientos sociales que se han desarrollado en los periodos de dictaduras y que se han organizado como formas de sobrevivencia de los sectores excluídos política, social y económicamente: o políticas populistas, o situar la recuperación económica por encima de las demandas sociales. Por su parte la acción de los movimientos sociales hoy puede llevarles a una estrategia autodestructiva: su triunfo signIficaría una mayor crisis social; su fracaso provocan'a el desencanto de los ciudadanos con los partidos políticos y los movimientos sociales.ABSTRACT: Nowadays, when Latin America is in a period of recovering democracy, the political system can develop two ways of approaching the social movements which have arised during dirtatorial regimes and which have been organized as forms of survival by groups that are excluded either in political, social or economic terms: either populist politics or economic recovery above social demands. As for social movements, their action might take them to an autodestructive strategy: their victory would mean a bigger social crisis; their failure would provoke in citizenship disillusion towards potitical parties and social movements.
¿Cómo hacer sustentables las ciudades?
Authors: Villasante Tomás R.
Published: March 2020

RESUMEN: Las ciudades, como producto social, no han dejado de cambiar con el paso del tiempo. Y tales cambios han conllevado las correspondientes transformaciones de los métodos de conocimiento e intervención en la ciudad. En los tiempos actuales, marcados por la globalización, la construcción de sentido de las ciudades requiere plantearse y responder a las preguntas de por qué, para qué, para quién y cómo analizamos e intervenimos en las ciudades de modo que sean sustentables. El artículo profundiza en estas cuestiones y ofrece ejemplos de prácticas urbanas basadas en la participación social.ABSTRACT: Cities, as social products, are in permanent change. These changes produce transformations about ways of acknowledge and intervention in cities. Nowadays, characterized by globalization, construction of significance of cities requires anwsers to questions about what, for who and how we analyse and intervene in cities in order they were sustainable. This article goes deeply into these questions and offers cases of urban practices based on social participation.
Movimientos Sociales y Democracia. Notas sobre la Crisis del Sindicalismo Boliviano
Authors: Ibañez Rojo Enrique
Published: March 2020

RESUMEN: El caso boliviano demuestra el papel decisivo jugado por los movimientos sociales en los procesos de transición denwcrática. Así como ,sus carencias atribuidas a la peculiar "cultura política" del movimiento obrero boliviano. Sin embargo un análisis del contexto de la transición - caótico, vioknto y con fuerte polarización ideológica - exige la consideración de un conjunto de variables estructurales. La multiplicación de la "incertidumbre estructural" favorecid la inhibición de la acción estratégica constructiva de la COB que junto a las disfuncionalidad de su propuesta sindicalista en una sociedad heterogénea, explica la incapacidad de la central para encauzar el proceso en favor de sus intereses. Se sugiere la urgencia de recomponer la mediación política capazde articular la dispersión del campo popular mediante fórmulas adecuadas a la estructura social y a la tradición hiktórica boliviana.ABSTRACT: The bolivian case shows the decisive rol played by social movements in the proceses towards democracy, so as their lacks, due to the peculiar "political culture" in labor movement. Nevertheless a further analysis of the transition environment - caotic, violent and with a high polarization - has to take into account a set of structural variables. So, the multiplication of structural uncertainty favourend the inhibition of the strategic constructive action of COB that added to plus disfuncionality of the union proposals in a heterogeneous society, explain the union uncapability for guiding the process towards its own interests. Its also suggested the urgency of rebuilding the political mediation capable of structuring the dispersed popular sector by means of suittable formulas to the social structure and historic traditions of Bolivia.
Chile. Actores Populares en la Protesta Nacional, 1983-1984
Authors: Revilla Blanco Marisa
Published: March 2020

RESUMEN: Los acontecimientos y los actores implicados en las movilizaciones producidas en Santiago de Chile en 1983-84, son el objeto de andlisis de este artículo. Tras una breve exposición del contexto económico y político, se describen los rasgos fundamentales y la evolución de las protestas. Del análisis de los hechos se deducen tres objetivos implícitos en las movilizaciones: recuperación de la identidad política y social, integración polltica de los excluidos y democracia. Los resultados son dispares; mientras en el plano político se produce una derrota, en lo referente a la expresividad de las acciones y al problema de la integración, las movilizaciones fueron exitosas.ABSTRACT: ThLs article focuses on the events and actors involved in the mobilizations tha took place in Santiago de Chile between 1983-1984. After a short exposition of the political and economic context, it describes the main characteristics and the protest's evolution. Three implicit objetives can be identified from the demostrations: the recovering of social and political identity, the political integration of the excluded people and democracy. The results are inequal; while on the political level a defeat ocurs, with regard to the expressiveness of the actions and the integration's problem, the mobilizations were successful.
La institucionalización de los sistemas de partido en la América Latina
Authors: Mainwaring Scott , Scully Timothy R.
Published: March 2020

RESUMEN: Estos autores señalan que la institucionalización de un sistema de partidos es importante en el proceso de consolidación democrática en la mayoría de los países latinoamericanos. Un sistema de partidos institucionalizado implica estabilidad en la competición intrapartidista, la existencia de partidos con raíces estables en la sociedad, la legitimidad de partidos, elecciones e instituciones, y unas organizaciones partidistas con reglas y estructuras razonablemente estables. También establecen diferencias en el grado de institucionalización y tratan de caracterizar los distintos sistemas de partidos en América Latina.ABSTRACT: These authors argue that institutionalizing a party system is important to the process of democratic consolidation in mast of Latin American countries. An institutionalized party system implies stability in interparty competition, the existence of parties that have stablee roots in society, the legitimacy of parties elections and institutions and party organizations with reasonably stablee rules and estructures. They also establish differences in the degree of institutionalization and try to charaterize the district party systems in Latin America.
Movilización y desmovilización del movimiento obrero en la transición chilena a la democracia
Authors: Durán Muñoz Rafael
Published: March 2020

RESUMEN: Según las propias palabras del autor, el presente artículo intenta analizar la importancia del nivel y la naturaleza de las movilizaciones sociales de presión y/o protesta en la determinación tanto del acaecimiento como de la naturaleza del proceso de transición hacia la democracia en Chile en los últimos años. Este análisis se presenta como un estudio complementario (aunque crítico) del modelo explicativo de los especialistas en transitología de la contingencia. Desde esta perspectiva, el autor sugiere que dado que la desmovilización social comenzó en el período de liberalización del régimen (1985/86) el costo de la misma fue mucho menor para las autoridades dictatoriales.ABSTRACT: This article analyses the characteristics of social protest mobilizations and their implications on the transition towards democracy in Chile. This analysis criticizes and complementa those explanations of democratic transitions which emphasize contingence. In this analysis, the author argues that since social mobilization started in the same period as the liberalization process (1985-86), such a mobilization had low costs for the military regime.
Élites parlamentarias e intergración subregional en América Latina
Authors: Alcántara Sáez Manuel , Freindenberg Flavia
Published: March 2020

RESUMEN: El objetivo de este trabajo es presentar las opiniones de las élites parlamentarias de los países miembros del Sistema de la Integración Centroamericana (SICA), la Comunidad Andina y el Mercosur hacia aquellos esquemas de integración económica donde su país es miembro activo; hacia las distintas fórmulas de integración subregional y hacia el interés de sus países de participar en esos sistemas de integración.ABSTRACT: This paper presents the opinions of the parlamentarians elites from the countries member of the System of the Central American Integration (SIGA), the Andean Community and the Mercosur regarding the performance of economic integration member shipspecial attention is paid to the interest of their countries in participating in these systems of integration.
Los retos de la economía mexicana más allá de la apertura comercial
Authors: Murayama Rendón Ciro
Published: March 2020

RESUMEN: Este artículo presenta la evolución reciente de la economía mexicana en el marco del proceso de integración en que está inserta. Especialmente analiza las consecuencias de la crisis de 1995 para las relaciones externas de México y para la evolución del Trabajo de Libre Comercio que lo vincula con Canadá y Estados Unidos. Finalmente se refiere a las repercusiones de este proceso en el empleo.ABSTRACT: This article presents recent evolution of Mexican economy on the frame of its integration process. I focuses on consequences of 1995 crisis for Mexican international relations and for evolution of the TLC. Finally, it refers to its echoes on the employment.
La iniciativa Bush para las americas: ¿Gesto vacio, hábil estrategia o cambio reseñable en las relaciones continentales?
Authors: Tulchin Josep S.
Published: March 2020

RESUMEN: El autor de este artículo aborda el análisis de la Iniciativa Bush para las Américas a dos años vista de su exposición por los portavoces de la Casa Blanca. Los escasos logros alcanzados no serán obstáculo para que Joseph S. Tulchin muestre un moderado optimismo por el desarrollo de la Iniciativa y los desafíos que le aguardan en los años próximos. Tras contextualizarla en el marco histórico del final de la guerra fría y del comienzo del desenvolvimiento a nivel global de las políticas económicas neoliberales, se pasa revista a los problemas por los que ha pasado la idea original en el interior de Estados Unidos y el entusiasmo con que fue acogida en América Latina. En este contexto uno de los primeros "tests" que pondrán a prueba el avance real de la Iniciativa para las Américas, será, sin lugar a dudas, la firma del Tratado de Libre Comercio (NAFTA) con México.ABSTRACT: The author of this article tackles the analysis of the Enterprise for the Americas Initiative (EA1) two years after the White House spokesmen threw the idea. Scarce results achieved, won't be obstacle for Joseph S. Tulchin when he proves a moderate optimism with the development of the EAI and the coming challenges in the years ahead. After pointing the context out the EAI in the end of the Cold War and the evolution of neoliberal economics policies frame, he reviews difficulties to implement the original idea incide the United States and the enthusiastic reaction in Latin America. In this context, one of the first facts that will put the EAI real advance to the test, shall be without no doubt, the Free Trade Treaty(NAFTA) signing with Mexico.