bluuebunny/crossref_metadata_2025 huggingface dataset:
Horror Cities
Authors: Balthaser Benjamin
Published: April 2020

In both art and politics, the deindustrialized city would seem to have taken on the qualities of the “unrepresentable,” a traumatic experience that can only be recorded by its attendant silence, or of depoliticized representation in genres such as “ruin porn.” Despite or perhaps because of this, the postindustrial city is ubiquitous within the genres of scifi/speculative, fantasy, and horror cinema, appearing consistently as backdrop, symbol, animus, and even in some cases, character. Given the wide literature on horror film, haunting, and traumatic memory, this article suggests we read the emergence of the “horror city” as a representation of the political unconscious of this historical conjuncture. Many films refer back to older mythologies of imperial and racial conquest, but also by doing so represent the symbol of modernity—the city—as travel back to a traumatic past. Yet within this return to history, there is a contest over allegory. Contrasting neoconservative narratives of films like The Road (dir. John Hillcoat, US, 2009) and the slasher film Hostel (dir. Eli Roth, US/Germany/Czech Republic/Slovakia/Iceland, 2005) suggests that the future has not vanished but rather has been spatially dislocated to the peripheries, as the modern site of production returns to inflict pain only on those unaware of its existence. And perhaps more radical still, two independent films, Vampz (dir. Steve Lustgarten, US, 2004) and Hood of the Living Dead (dir. Eduardo and Jose Quiroz, US, 2005), suggest that the abandoned city is still a site for the basic labor of human reproduction even as the infrastructure of full employment has vanished. As a counternarrative to both “ruin porn” and the “horror city,” these low-budget films offer the deindustrialized city as a site of mutuality and political contestation rather than a mystified object of horror and abjection.
Heterogeneous nuclear ribonucleoprotein A3a controls mitotic progression of neural progenitors via interaction with cohesin
Authors: Ou Min-Yi , Ju Xiang-Chun , Cai Yi-Jun , Sun Xin-Yao , Wang Jun-Feng , Fu Xiu-Qing , Sun Qiang , Luo Zhen-Ge
Published: April 2020

Cortex development is controlled by temporal patterning of neural progenitor (NP) competence with sequential generation of deep and superficial layer neurons, but underlying mechanisms remain elusive. Here, we report a role of heterogeneous nuclear ribonucleoprotein A3 (HNRNPA3) in regulating the division of early cortical NPs that mainly give rise to deep-layer neurons via direct neurogenesis. HNRNPA3 is highly expressed in NPs of mouse and human cortex at early stages with a unique peri-chromosome pattern. Intriguingly, down-regulation of HNRNPA3 caused chromosome disarrangement, which hindered normal separation of chromosomes during NP division, leading to mitotic delay. Furthermore, HNRNPA3 is associated with the cohesin-core subunit SMC1A and controls its association with chromosomes, implicating a mechanism for the role of HNRNPA3 in regulating chromosome segregation in dividing NPs. Hnrnpa3 deficient mice exhibited reduced cortical thickness, especially of deep layers. Moreover, down-regulation of HNRNPA3 in cultured human cerebral organoids led to marked reduction in NPs and deep-layer neurons. Thus, this study has identified a critical role of HNRNPA3 in NP division and highlighted the relationship between mitosis progression and early neurogenesis.
On the regeneration of fish scales: structure and mechanical behavior
Authors: Ghods S. , Waddell S. , Weller E. , Renteria C. , Jiang H.-Y. , Janak J. M. , Mao S. S. , Linley T. J. , Arola D.
Published: April 2020

Fish scales serve as a dermal armor that provides protection from physical injury. Due to a number of outstanding properties, fish scales are inspiring new concepts for layered engineered materials and next-generation flexible armors. While past efforts have primarily focused on the structure and mechanical behavior of ontogenetic scales, the structure-property relationships of regenerated scales have received limited attention. In the present study, common carp (Cyprinus carpio) acquired from the wild were held live in an aquatic laboratory at 10° and 20°C. Ontogenetic scales were extracted from the fish for analysis, as well as regenerated scales after approximately 1 year of development and growth. Their microstructure was characterized using microscopy and Raman spectroscopy, and the mechanical properties were evaluated in uniaxial tension to failure under hydrated conditions. The strength, strain to fracture and toughness of the regenerated scales were significantly lower than those of ontogenetic scales from the same fish, regardless of the water temperature. Scales that regenerated at 20°C exhibited significantly higher strength, strain to fracture and toughness than those regenerated at 10°C. The regenerated scales exhibited a highly mineralized outer layer, but no distinct limiting layer or external elasmodine; they also possessed a significantly lower number of plies in the basal layer than in the ontogenetic scales. The results suggest that a mineralized layer develops preferentially during scale regeneration with the topology needed for protection, prior to the development of other qualities.
Fly eyes are not still: a motion illusion in Drosophila flight supports parallel visual processing
Authors: Salem Wael , Cellini Benjamin , Frye Mark A. , Mongeau Jean-Michel
Published: April 2020

Most animals shift gaze by a ‘fixate and saccade’ strategy, where the fixation phase stabilizes background motion. A logical prerequisite for robust detection and tracking of moving foreground objects, therefore, is to suppress the perception of background motion. In a virtual reality magnetic tether system enabling free yaw movement, Drosophila implemented a fixate and saccade strategy in the presence of a static panorama. When the spatial wavelength of a vertical grating was below the Nyquist wavelength of the compound eyes, flies drifted continuously­ and gaze could not be maintained at a single location. Because the drift occurs from a motionless stimulus—thus any perceived motion stimuli are generated by the fly itself—it is illusory, driven by perceptual aliasing. Notably, the drift speed was significantly faster than under a uniform panorama suggesting perceptual enhancement due to aliasing. Under the same visual conditions in a rigid tether paradigm, wing steering responses to the unresolvable static panorama were not distinguishable from a resolvable static pattern, suggesting visual aliasing is induced by ego motion. We hypothesized that obstructing the control of gaze fixation also disrupts detection and tracking of objects. Using the illusory motion stimulus, we show that magnetically tethered Drosophila track objects robustly in flight even when gaze is not fixated as flies continuously drift. Taken together, our study provides further support for parallel visual motion processing and reveals the critical influence of body motion on visuomotor processing. Motion illusions can reveal important shared principles of information processing across taxa.
The metabolic response to an immune challenge in a viviparous snake, Sistrurus miliarius
Authors: Lind C. M. , Agugliaro J. , Farrell T. M.
Published: April 2020

Mounting an immune response may be energetically costly and require the diversion of resources away from other physiological processes. Yet, both the metabolic cost of immune responses and the factors that impact investment priorities remain poorly described in many vertebrate groups. For example, although viviparity has evolved many times in vertebrates, the relationship between immune function and pregnancy has been disproportionately studied in placental mammals. To examine the energetic costs of immune activation and the modulation of immune function during pregnancy in a non-mammalian vertebrate, we elicited an immune response in pregnant and non-pregnant pygmy rattlesnakes, Sistrurus miliarius, using lipopolysaccharide (LPS). Resting metabolic rate (RMR) was measured using flow-through respirometry. Immune function was examined using bactericidal assays and leukocyte counts. The RMR of pygmy rattlesnakes increased significantly in response to LPS injection. There was no statistically significant difference in the metabolic response of non-reproductive and pregnant snakes to LPS. Mean metabolic increments for pregnant females, non-reproductive females, and males were 13%, 18%, and 26%, respectively. The ratio of heterophils to lymphocytes was elevated in response to LPS across reproductive categories; however, LPS did not impact plasma bactericidal ability in non-reproductive snakes. Although pregnant females had significantly higher plasma bactericidal ability compared to non-reproductive snakes prior to manipulation, their bactericidal ability declined in response to LPS. LPS administration also significantly reduced several litter characteristics, particularly when administrated relatively early in pregnancy. Our results indicate that immune performance is energetically costly, altered during pregnancy, and that immune activation during pregnancy may result in tradeoffs that affect offspring in a viviparous reptile.
Red-Light-Mediated Barton–McCombie Reaction
Authors: Ogura Akihiro , Ichii Naoki , Shibata Kouhei , Takao Ken-ichi
Published: April 2020

A red-light-mediated Barton–McCombie reaction is described, in which chlorophyll a is used as a photocatalyst and tris(trimethylsilyl)silane or Hantzsch ester is used as the hydrogen source. The reaction can be performed with a set of easily available equipment and reagents, and a variety of linear and cyclic xanthates could be applied. In contrast to the traditional conditions, the reaction does not involve toxic organotin or an explosive radical initiator. The reaction mechanism was analyzed both by experiments and computation, and it was suggested that the radical chain mechanism initiated by excitation of complex followed by charge transfer is likely to be operative.
An extensive sclerosing odontogenic carcinoma in mandible: a case report and literature review
Authors: Seyiti Pakezhati , Feng Yinglian , Gao Antian , Lin Zitong , Huang Xiaofeng , Sun Guowen , Zhang Lei , Wang Tiemei
Published: April 2020

Sclerosing odontogenic carcinoma (SOC) is a primary intraosseous carcinoma of the jaw that was listed as a separate entity for the first time in the latest version of the World Health Organization classification of Head and Neck Tumors (2017). In this report, we present a case of SOC involving a circuitous diagnostic process because of the inadequately detailed biopsy findings and inherent impression based on the imaging manifestations. Through an extensive literature review, the histopathological and immunohistochemical features of the disease were briefly summarized. Radiological findings of SOC have been characterized in detail, and an imaging classification scheme has been proposed to further discuss the diversity of radiographic features. Due to the rarity of the disease, a comprehensive understanding of SOC is needed, and close collaboration between clinicians, radiologists, and pathologists is crucial to avoid misdiagnosis.
Eessõna
Authors: Leijen Äli , Mikser Rain , Krull Edgar
Published: April 2020

Uus EHA erinumber keskendub õpetaja professionaalsuse ja professionaalse arengu temaatikale. Tänapäeval oodatakse professionaalidelt järjepidevat teadmiste ja oskuste uuendamist. See on muutnud arusaama sellest, kes on professionaal. Minevikus oli paljudes valdkondades võimalik omandada peamised erialaoskused ja -teadmised esmaõppe käigus ning pidev erialane enesetäiendamine ei olnud tingimata vajalik. Tänapäeval ei ole selline teguviis enam võimalik. Eeldatakse, et iga professionaal, ka õpetaja, täiendab end kogu ametiaja jooksul. Erinumbri keskmes on ühelt poolt üks konkreetne teema Eesti õpetajate töös – kaasava hariduse põhimõtete tähenduslik rakendamine Eesti kontekstis – ja teiselt poolt märksa laiemad küsimused seoses õpetaja professionaalsuse ja professionaalse arenguga.
Läbilõikeline ülevaade üliõpilaste hinnangutest Tartu Ülikooli õpetajakoolituse õppekavade sidususele 2014.–2018. aastal
Authors: Malva Liina , Leijen Äli
Published: April 2020

Õpetajakoolitus on praktikaga tihedalt seotud õppevaldkond, kuid siiski on teooria ja praktika sidumine õpetajakoolituses veel paljudes riikides proovikivi (Darling-Hammond, 1999; Hammerness & Klette, 2015). Tartu Ülikoolis hakati selle kitsaskohaga ulatuslikult tegelema 2013. aastast, uuendades õpetajakoolituse alus- ja praktikamoodulit. Selleks, et läbi aastate tehtud muudatuste tulemuslikkust seirata, on alates 2014. aastast igal sügisel alusmooduli üliõpilaste seas (n = 572) kogutud andmeid nende hinnangute kohta õppekava sidususele. Tulemused näitavad, et üliõpilaste hinnangul on märgatavalt paranenud nii teoreetiliste õppeainete kooskõla praktikal kogetuga kui ka võimalused õppekava osi omavahel siduda. Samas leiti, et ülikooli õppetöös on liiga vähe tegevusi, mis valmistaksid üliõpilasi ette õppija arengust lähtumiseks õpetajatöös. Ülikooli õppeained keskenduvad enam õppe kavandamisele ja analüüsile, vähem tegeletakse õppetöö tegevustega.

 Summary
De recolectores a cultivadores certificados: tensiones y articulaciones de saberes territoriales en la Reserva de la Biosfera Los Tuxtlas, Veracruz (México)
Authors: Velázquez Emilia , Ramírez Fernando
Published: April 2020

En este artículo se discute cómo al amparo de la creación de áreas naturales protegidas se generan nuevas territorializaciones que se sobreponen a territorios y territorializaciones ya existentes. Cada una de estas territorializaciones está anclada a saberes territoriales particulares, que responden a intereses y valoraciones de la naturaleza a veces contrapuestos. Se analizó cómo la creación de un área natural protegida, basada en un saber territorial experto, impactó las modalidades y posibilidades de acceso a recursos forestales esenciales para la economía familiar de varias poblaciones. Mostramos que en torno a la recolección de un recurso forestal no maderable existente en la montaña, los campesinos crearon su propio saber territorial. El cambio de extracción a cultivo de este recurso trastocó dicho saber. Los resultados aquí presentados son producto de un largo trabajo de campo en el que se combinó la investigación-acción y el trabajo etnográfico.
A metapopulation model for whale-fall specialists: The largest whales are essential to prevent species extinctions
Authors: Smith Craig R. , Roman Joe , Nation J. B.
Published: April 2020

The sunken carcasses of great whales (i.e., whale falls) provide an important deep-sea habitat for more than 100 species that may be considered whale-fall specialists. Commercial whaling has reduced the abundance and size of whales, and thus whale-fall habitats, as great whales were
hunted and removed from the oceans, often to near extinction. In this article, we use a metapopulation modeling approach to explore the consequences of whaling to the abundance and persistence of whale-fall habitats in the deep sea and to the potential for extinction of whale-fall specialists.
Our modeling indicates that the persistence of metapopulations of whale-fall specialists is linearly related to the abundance of whales, and extremely sensitive (to the fourth power) to the mean size of whales. Thus, whaling-induced declines in the mean size of whales are likely to have been
as important as declines in whale abundance to extinction pressure on whale-fall specialists. Our modeling also indicates that commercial whaling, even under proposed sustainable yield scenarios, has the potential to yield substantial extinction of whale-fall specialists. The loss of whale-fall
habitat is likely to have had the greatest impact on the diversity of whale-fall specialists in areas where whales have been hunted for centuries, allowing extinctions to proceed to completion. The North Atlantic experienced dramatic declines, and even extirpation, of many whale species before
the 20th century; thus, extinctions of whale-fall specialists are likely to have already occurred in this region. Whale depletions have occurred more recently in the Southern Hemisphere and across most of the North Pacific; thus, these regions may still have substantial "extinction debts,"
and many extant whale-fall specialists may be destined for extinction if whale populations do not recover in abundance and mean size over the next few decades. Prior to the resumption of commercial whaling, or the loosening of protections to reduce incidental take, the impacts of hunting on
deep-sea whale-fall ecosystems, as well as differential protection of the largest whales within and across species, should be carefully considered.
Study of a fiber spectrometer based on offset fusion
Authors: Wang Tianliang , Li Yi , Meng Yanlong , Qiu Yanqing , Mao Bangning
Published: April 2020

A near-infrared spectrometer based on offset fused multimode fiber (MMF) is investigated in this study. The light spectrum is recovered by analyzing the speckle images when light is passing through the MMF. In order to generate adequate speckles, a polarization maintaining fiber (PMF) and a 30 cm long MMF are fused with a vertical offset. Seven different offset displacements are implemented in the fiber fusion. The follow-up experiments show that the fiber offset fusion has a significant influence on the spectral correlation and the resolution. Larger offset fusion can excite more high-order modes in the MMF, and it greatly improves the spectrometer’s performance. The simulation results also show that more modes are excited in MMF, and the increase of mode number leads to lower correlation coefficients of the neighboring spectral channels. However, large offset fusion increases the fusion and the insertion loss of the whole system, which may bring difficulties in the low-light cases. In addition, an image denoising algorithm based on dynamic threshold filtering and a spectral reconstruction algorithm originated from complete orthogonal decomposition were used to remove the speckle pattern noise and recover the spectrum. The final speckle-based spectrometer has a spectral resolution of

0.6

∼
0.016

n
m

depending on the different offset fusions.
Tilted wavefront coding system to eliminate the retroreflection with superior imaging property: publisher’s note
Authors: Wang Lei , Ye Qing , Nie Jinsong , Sun Xiaoquan
Published: April 2020

This publisher’s note corrects information in the author affiliations
in Appl.
Opt. 58, 7205
(2019).APOPAI0003-693510.1364/AO.58.007205
Digital sorting perturbed Laguerre–Gaussian beams by radial numbers
Authors: Volyar A. , Bretsko M. , Akimova Ya. , Egorov Yu.
Published: April 2020

We developed a new alterative technique of the digital sorting of Laguerre–Gaussian beams (LG) by radial numbers resorting to algebra of the high-order intensity moments. The term “digital mode sorting” involves sorting the main mode characteristics (in the form of a mode spectrum) by the computer cells. If necessary, the spatial mode spectrum can be reproduced, for example, by means of a spatial light modulator. In the experiment, we investigated both a single LG mode and a composition of LG modes with the same topological charge but different radial numbers subjected to perturbations via a hard-edged circular aperture. The LG beams sorting was accomplished by monitoring the amplitude spectrum of the triggered secondary LG modes then recovering the sorted modes and the perturbed beam as a whole. We have revealed degenerate states of the perturbed LG beam composition when the one

k

th mode in the amplitude spectrum can be related to a set of LG modes with the same radial numbers. In order to decrypt and to sort beams in such a degenerate state, it is necessary to know several keys, the number of which is equal to the number of LG modes in the initial wave composition. We were also able to analyze and to sort such degenerate mode states. For monitoring the measure of uncertainty arising in the perturbed beam, we measured informational entropy (Shannon entropy).
Design guidelines for normal-dispersion fiber optical parametric chirped-pulse amplifiers
Authors: Fu Walter , Herda Robert , Wise Frank W.
Published: April 2020

We theoretically investigate methods of controlling pulse generation in normal-dispersion fiber optical parametric chirped-pulse amplifiers. We focus on high-energy, ultrashort pulses at wavelengths widely separated from those of the pump, and find that within this regime, a number of simple properties describe the essential phase and gain dynamics. Of primary importance are the relationships between the chirps of the pump, seed, and parametric gain, which we theoretically predict and then experimentally validate. By properly arranging these parameters, the signal and idler waves can be widely customized to fulfill a remarkable range of application requirements, spanning from narrowband to few-cycle.
Linear cavity tapered fiber sensor using mode-tracking phase-shift cavity ring-down spectroscopy
Authors: Ayaz Rana M. Armaghan , Uysalli Yigit , Morova Berna , Bavili Nima , Ullah Ubaid , Ghauri M. Daniyal , Cheema M. Imran , Kiraz Alper
Published: April 2020

Phase-shift cavity ring-down spectroscopy (PS-CRDS) is an alternative CRDS approach that allows the detection of minute changes in cavity losses by measurement of the phase shift experienced by a modulated laser as it propagates through a high-quality factor cavity. Fiber loop resonators and microresonators have been employed in previous PS-CRDS demonstrations for liquid phase applications. Here we employ a tapered fiber-based linear fiber cavity for the demonstration of a highly sensitive sensor for sucrose concentration in water using PS-CRDS. Our linear fiber cavity has a small cavity length (

∼

1.25

m

) that enables the observation and tracking of individual cavity modes in transmission and phase spectra recorded during laser sweeps. Hence, we eliminate the need for Pound–Drever–Hall locking of the laser source to the cavity resonance and thus provide a simpler experimental scheme. We analyze the recorded data sets to track the changes in phase shifts observed only when the laser wavelength is in resonance with the cavity modes. Such a mode-tracking PS-CRDS approach reveals limit of detection values less than around 400 µM, better than the performance of previously demonstrated PS-CRDS sucrose concentration sensors employing fiber loop resonators. The sensitivity of our sensor critically depends on the fiber taper diameter and can reach up to around 6°/1 mM Suc. for 3.2 µm taper diameter at 6 MHz modulation frequency using fiber Bragg gratings (FBGs) with reflectivities around 86%. This value can be further increased by employing FBGs with higher reflectivities or fiber tapers with smaller diameters provided that the cavity loss due to water absorption is compensated with an amplifier.
Ratiometric optical thermometry based on temperature-induced shift of V-O charge transfer band edge
Authors: Zhou Shaoshuai , Li Xiaoman , Zhang Shoubao , Zhao Hongyan
Published: April 2020

Ratiometric optical thermometry was designed using temperature-induced shift of V-O charge transfer band (CTB) edge combined with temperature-induced variation of Tb3+ emission in YV1-xPxO4. P was introduced into YVO4 lattice to form YV1-xPxO4 solid solution successfully, with the purpose of enhancing Tb3+ emission. Under 352 nm excitation which locates in the tail of the V-O CTB, emission spectra of YV0.3P0.7O4:Tb3+, Eu3+/Sm3+ were recorded at a series of temperatures ranging from 300 to 440 K. It is demonstrated that Tb3+ and Eu3+/Sm3+ emissions exhibit opposite temperature dependences. The mechanisms for such opposite variations have been interpreted in detail. Based on the varied fluorescence intensity ratio of Eu3+/Sm3+ to Tb3+ with temperature, high relative sensitivity was obtained with a maximal value of 2.85% K−1 around 365 K. Our results imply that the proposed strategy is a promising candidate for high-sensitive optical temperature sensing.
Investigation of a noise source and its impact on the photocurrent performance of long-wave-infrared InAs/GaSb type-II superlattice detectors
Authors: Meng Chenxu , Li Jinlan , Yu Le , Wang Xiaomu , Han Ping , Yan Feng , Xu Zhicheng , Chen Jianxin , Ji Xiaoli
Published: April 2020

Electrical noise significantly limits the detectivity of infrared photodiode detectors. In this paper, we investigated the dark current and noise spectra for long-wave-infrared InAs/GaSb type-II superlattice (T2SL) detectors to study the origin of noise under various work conditions. The temperature-dependent I-V characteristics reveal a turning point near 90 K, below which the dominant dark current mechanism changes from Shockley-Hall-Read generation current and diffusion current to shunt current and trap-assisted tunneling (TAT) current. The contribution of shunt and tunneling process to the total 1/f noise are analyzed by fitting the noise power spectral density at 77 K for detectors. It is found that the TAT current dominates the 1/f noise at the reverse bias stronger than -0.1 V, while shunt current exhibits a larger contribution at the reverse bias less than -0.1 V with the shunt noise coefficient αshunt of 5×10−8. Furthermore, the leakage routes related to the shunt process and their temperature dependence are illustrated by two-dimensional photocurrent mapping.
Surface plasmon coupled nano-probe for near field scanning optical microscopy
Authors: Yin Xiaojin , Shi Peng , Yang Aiping , Du Luping , Yuan Xiaocong
Published: April 2020

Near-field scanning optical microscopy (NSOM) is a powerful tool for study of the nanoscale information of objects by measuring their near-field electric field distributions. The near-field probe, which determines NSOM system performance, can be either a scattering-type or an aperture-type. Both types have strengths and weaknesses. Here we propose and study a surface plasmon-coupled type nano-probe, which works as a hybrid scheme and could potentially combine the advantages of the two NSOM probe types. The key element of the proposed probe is a nanoparticle-on-film structure designed on a tapered fiber tip. On the one hand, the probe can yield the signals scattered in the near field by a nanoparticle with a scattering mechanism; on the other hand, the scattered signals can be transmitted by the metal film and coupled into the fiber via surface plasmon coupled emission, thus providing a collection mode similar to an aperture-type NSOM. This will lead to signal enhancement, while greatly suppressing background noise. This surface plasmon-coupled nano-probe thus has great potential for near-field optical microscopy applications.
Low-noise distributed acoustic sensing using enhanced backscattering fiber with ultra-low-loss point reflectors
Authors: Redding Brandon , Murray Matthew J. , Donko Andrei , Beresna Martynas , Masoudi Ali , Brambilla Gilberto
Published: April 2020

We present a low-noise distributed acoustic sensor using enhanced backscattering fiber with a series of localized reflectors. The point reflectors were inscribed in a standard telecom fiber in a fully automated system by focusing an ultra-fast laser through the fiber cladding. The inscribed reflectors provided a reflectance of −53 dB, significantly higher than the Rayleigh backscattering level of −70 dB/m, despite adding only 0.01 dB of loss per 100 reflection points. We constructed a coherent φ-OTDR system using a double-pulse architecture to probe the enhanced backscattering fiber. Using this system, we found that the point reflectors enabled an average phase noise of −91 dB (re rad2/Hz), 20 dB lower than sensors formed using Rayleigh backscattering in the same fiber. The sensors are immune to interference fading, exhibit a high degree of linearity, and demonstrate excellent non-local signal suppression (>50 dB). This work illustrates the potential for low-cost enhanced backscattering fiber to enable low-noise, long-range distributed acoustic sensing.
Theory of autocalibration feasibility and precision in full Stokes polarization imagers
Authors: Li Xiaobo , Le Teurnier Benjamin , Boffety Matthieu , Liu Tiegen , Hu Haofeng , Goudail François
Published: April 2020

We propose a general theory of simultaneous estimation of Stokes vector and instrumental autocalibration of polarization imagers. This theory is applicable to any polarization imager defined by its measurement matrix. We illustrate it on the example of retardance autocalibration in a large class of polarization imagers based on rotating retarders and polarimeters. We show that although all these architectures can yield optimal estimation precision of the Stokes vector if they are properly configured, they do not have the same autocalibration capacity and have to be specifically optimized for that purpose. These results are important to determine the best compromise between autocalibration capacity and polarimetric precision in practical applications.
Linewidth characteristics of period-one dynamics induced by optically injected semiconductor lasers
Authors: AlMulla Mohammad , Liu Jia-Ming
Published: April 2020

Period-one (P1) nonlinear dynamics of optically injected semiconductor lasers exhibit periodic intensity fluctuations with operating frequencies that are tunable in the micro/millimeter-wave range. Through numerical experiments, the characteristics of the microwave linewidth of the P1 oscillation and the linewidths of its optical frequency components due to intrinsic laser noise sources are investigated. The field noise and carrier noise of the master and slave lasers are systematically considered. The contribution of the field noise of the master laser is significant; it considerably broadens the microwave linewidth of the P1 oscillation. When the operating conditions in the regions of high microwave power are properly adjusted, the microwave linewidth of the P1 oscillation becomes narrower than the free-running optical linewidths of the master and slave lasers. Regions with low sensitivity to time-dependent fluctuations in an operating parameter show reduced microwave linewidth of the P1 oscillation.
Investigation of dual-wavelength pump schemes for optically pumped rare gas lasers
Authors: Sun P. , Zuo D. , Wang X. , Han J. , Heaven M. C.
Published: April 2020

Optically pumped rare gas lasers (OPRGLs) have shown great potential to generate high energy laser radiation with high beam quality. As an alternative to the diode-pumped alkali vapor lasers (DPALs), they have similar working principles and characteristics, but OPRGLs have the advantage that the gain medium is chemically inert and is appropriate for closed-cycle operation. One of the challenges OPRGLs are faced with is the bottleneck caused by the slow 1s4-1s5 collisional relaxations at room temperature. A 1s4-2p10 dual-wavelength pump method had been proposed to transfer the populations pooled on the 1s4 level to the lasing cycle using a steady-state laser model. We explored this method further through 1s4-2p8 and 1s4-2p7 dual-wavelength pump schemes. The enhancement efficiencies at room temperature for a repetitively pulsed discharge, CW dual-wavelength pump system were examined using a dynamic model, and an experiment with a pulsed secondary pump was conducted for qualitative evaluations.
Fabrication and transmission of optical polymer waveguide backplane for high - performance computers
Authors: Yang Shuailong , Yang Liu , Li Bin , Luo Fengguang , Wang Xiaobo , Du Yuting
Published: April 2020

In this paper, a high-speed, large-capacity and compact optical backplane architecture for high-performance computers (HPC) is proposed and designed. The MT couplers is designed without additional mirror to divert the light from vertical cavity surface emitting laser (VCSEL) array by 90°. The light is then coupled into the optical waveguide through the MT. A bidirectional 8 channels polymer optical waveguide array with low insertion loss is designed and fabricated. The waveguides are embedded in the printed circuit board. We test the performance of 8 channels for the optical waveguide backplane. In the entire optical backplane, the averaged insertion loss of optical backplane with 50 μm input fiber is 1.62 dB with 850 nm VCSEL. The misalignment loss is 0.5 dB when the misalignment between waveguide and multi-mode fiber is 8.5 μm. Then, the transmission performances of 4 channels with different speed signals is demonstrated by off-line experiment. The optical backplane network can achieve 15 G data error-free transmission in the range of [-2 dBm, -10 dBm] received optical power (ROP). Based on VCSEL arrays, the optical interconnection network system can achieve 8 channels parallel signal transmission. In the optical backplane, the 10 Gbit / s data generated / processed by field programmable gate array (Xilinx Kintex-7) chips can realize error-free transmission. In large-capacity, high-speed parallel HPC, the designed optical backplane system can facilitate the establishment of a large number of parallel transmissions.
Selective ultrafast control of multi-level quantum systems by subcycle and unipolar pulses
Authors: Arkhipov Rostislav , Pakhomov Anton , Arkhipov Mikhail , Demircan Ayhan , Morgner Uwe , Rosanov Nikolay , Babushkin Ihar
Published: April 2020

The most typical way to optically control population of atomic and molecular systems is to illuminate them with radiation, resonant to the relevant transitions. Here we consider a possibility to control populations with the subcycle and even unipolar pulses, containing less than one oscillation of electric field. Despite the spectrum of such pulses covers several levels at once, we show that it is possible to selectively excite the levels of our choice by varying the driving pulse shape, duration or time delay between consecutive pulses. The pulses which are not unipolar, but have a peak of electric field of one polarity much higher (and shorter) than of the opposite one, are also capable for such control.
Active control of near-field radiative heat transfer by a graphene-gratings coating-twisting method
Authors: He Mingjian , Qi Hong , Ren Yatao , Zhao Yijun , Antezza Mauro
Published: April 2020

In this Letter, active control of near-field radiative heat transfer (NFRHT) between two isotropic materials is realized by a coating-twisting method. The two slabs are coated with graphene gratings, and then the NFRHT can be not only enhanced but also weakened, by tuning the twisted angle between the two gratings. The physical mechanism is attributed to the modes coupled by the graphene gratings and the isotropic material, which can vary with the twisted angle. The proposed method is also applicable for other kinds of anisotropic films and may provide a way to realize high-precision nanoscale thermal management, nimble thermal communications, and thermal switch.
Tailoring soliton fission at telecom wavelengths using composite-liquid-core fibers
Authors: Chemnitz Mario , Junaid Saher , Walther Nico , Scheibinger Ramona , Schaarschmidt Kay , Kobelke Jens , Schmidt Markus A.
Published: April 2020

Accurate dispersion management is key for efficient nonlinear light generation. Here, we demonstrate that composite-liquid-core fibers—fibers with binary liquid mixtures as the core medium—allow for accurate and tunable control of dispersion, loss, and nonlinearity. Specifically, we show numerically that mixtures of organic and inorganic solvents in silica capillaries yield anomalous dispersion and reasonable nonlinearity at telecommunication wavelengths. This favorable operation domain is experimentally verified in various liquid systems through dispersion-sensitive supercontinuum generation, with all results being consistent with theoretical designs and simulations. Our results confirm that mixtures introduce a cost-effective means for liquid-core fiber design that allows for loss control, nonlinear response variation, and dispersion engineering.
Transition-metal-doped saturable absorbers for passive Q-switching of visible lasers
Authors: Tanaka Hiroki , Kränkel Christian , Kannari Fumihiko
Published: April 2020

We experimentally investigate crystals doped with tetravalent chromium or divalent cobalt as saturable absorbers for passive Q-switching of visible solid-state lasers. The recovery time of the ground-state and excited-state absorption cross sections are determined by pump-probe and Z-scan measurements, respectively. We provide saturation intensities, useful wavelength ranges of the investigated materials, and advices to realize passive Q-switching of visible lasers using these crystals as saturable absorbers.
The strange case of the three-column screenplay format in 1950s Czechoslovakia
Authors: Černík Jan
Published: April 2020

In the nationalized Czechoslovak film industry, between 1952 and 1956, eight very rare three-column screenplays appeared. The historical evidence of this different screenplay format has been overlooked by historians up to now. Three-column screenplays are not just a dead end of screenwriting practice; they can also be read as evidence of basic tendencies within the Czechoslovak film industry in the 1950s. One effect of nationalization of the film industry was the attempt to standardize the organization of script development. The administrative intervention caused the modification of the script format, but instead of standardization, the effect was a multitude of formats, of which the three-column technical screenplays were a by-product. In this article I read these three-column screenplays within the industry context of the first half of the 1950s in Czechoslovakia and offer an in-depth analysis of particular three-column screenplays.
The origins of screenwriting practice and discourse in Portugal
Authors: Benis Rita
Published: April 2020

Following previous works by Patrick C. Loughney, Isabelle Raynauld, Steven Maras, Ian Macdonald, Alain Carou and Steven Price on screenwriting’s historical development in national frameworks, this article proposes to examine Portuguese screenwriting historical culture in relation to its major external influences: French, Italian and American cinema. If it is true that American mainstream cinema and its screenwriting models are now hegemonic and increasingly present in Portuguese film culture, it is also true that Portugal had (and continues to have) a strong ‘author-oriented’ film tradition, focused on artistic processes, clearly present in its screenwriting culture. Such characteristics developed first under the influence of French and Italian silent cinema, through the contribution of foreign film directors who worked in Portugal and established schools there. Also important were the cinematographic experiences (film and writing) made by modernist poets during the silent film period. Finally, the powerful influence of the French Politique des Auteurs (1950s) also helped to configure Portuguese screenwriting culture. To contextualize the Portuguese experience specifically, I explore the origins of screenwriting practice and discourse in Portugal, addressing the many political, historical and financial aspects that impacted the Portuguese perception of screenwriting craft from an early stage.
Campañas presidenciales de 2018 en México: nivel de profesionalización, equipo de campaña y estrategias políticas
Authors: González Tule Luis , Restrepo Echavarría Néstor Julián
Published: April 2020

En las últimas dos décadas las campañas presidenciales en México han evidenciado una mayor profesionalización. Partidos y candidatos realizan encuestas, planean estrategias discursivas, hacen uso intensivo de nuevas tecnologías, personalizan la campaña en el candidato y contratan a especialistas en marketing político, imagen, medios de comunicación, redes sociales y producción audiovisual. Considerando estos avances, cabe plantearse: ¿cuál es el nivel de profesionalización de las campañas electorales? En el presente trabajo nos planteamos 1) medir el nivel de profesionalización de las campañas presidenciales mexicanas de 2018 y 2) identificar las áreas de mayor desarrollo e innovación y las diferencias que presentaron los equipos de los tres candidatos más votados. Para medir el nivel de profesionalización, construimos un índice que permite hacer comparaciones tanto al interior de un sistema partidista como al exterior de este.
COVID-19 and SARS-COV-2 Infection and Virulence, Hypothesis II: Elevated Temperature, Humidity and Far Infrared Irradiation will significantly lower the Viability, Infectivity and Virulence of SARS-COV-2
Authors: Tung H.Y. Lim
Published: April 2020

SARS-COV-2 is the etiologic agent of COVID-19. There is currently no effective means of preventing infections by SARS-COV-2, except through restriction of population movement and contact. An understanding of the origin, evolution and biochemistry (molecular biology) of SARS-COV-2 is a prerequisite to its control. There is no definitive answer as to the origin of SARS-COV-2. The evolution of SARS-COV-2 can be gleaned from a comparative study of its infectivity and virulence in different populations and environments. There are few reports on the biochemistry (molecular biology) of SARS-COV-2. Analysis of the biochemistry (moleuclar biology) of SARS-COV-2 and past discoveries of viruses that infect humans revealed that SARS-COV-2 most probably emerged from its latent forms through induction by Low Temperature, Low Sunlight and Low Humidity caused by Seasonal Change and Drought. Far Infrared Radiation (FIR), an important component of Sun Light can eradicate RNA viruses. Thus, it is hypothesized that an environment of high humidity, temperature approaching 39
0C (or higher) and Far Infrared Irradiation will significantly lower the viability and infectivity of SARS-COV-2 and enhance the recovery of individuals infected with SARS-COV-2. Increasing the temperature and humidity with constant Far Infrared Irradiation in the room in which individuals infected with SARS-COV-2 are being treated is relatively easy to implement. Protocol for irradiation with FIR which is not harmful to humans but will destroy SARS-COV-2 already exists and can be implemented relatively easy. It is also hypothesized that the process of steaming up to 70
0 C - 80
0 C in a FIR Sauna may not only reduce the viability and infectivity of SARS-COV-2 but also enhance the recovery of individuals infected with SARS-COV-2. It is further hypothesized that Individuals infected with SARS-COV-2 who have mild symptoms and Asymptomatic Carriers of SARS-COV-2 will also benefit from steaming in a FIR Sauna. These hypotheses are realtively easy to test and will take no more than two weeks to accomplish.
Investigation of potential inhibitor properties of ethanolic propolis extracts against ACE-II receptors for COVID-19 treatment by Molecular Docking Study
Authors: Güler Halil Ibrahim , Tatar Gizem , Yildiz Oktay , Belduz Ali Osman , Kolayli Sevgi
Published: April 2020

The angiotensin-converting enzyme (ACE)-related carboxypeptidase, ACE-II, is a type I integral membrane protein of 805 amino acids that contains one HEXXH-E zinc binding consensus sequence. ACE-II has been implicated in the regulation of heart function and also as a functional receptor for the coronavirus that causes the severe acute respiratory syndrome (SARS). In this study, the potential of some flavonoids present in propolis to bind to ACE II receptors was calculated in silico. Binding constants of ten flavonoids, caffeic acid, caffeic acid phenethyl ester, chrysin, galangin, myricetin, rutin, hesperetin, pinocembrin, luteolin and quercetin were measured using the AutoDock 4.2 molecular docking program. And also, these binding constants were compared to reference ligand of MLN-4760. The results are shown that rutin has the best inhibition potentials among the studied molecules with high binding energy -8,97 kcal/mol and Ki 0,261 M, and it is followed by myricetin, caffeic acid phenethyl ester, hesperetin and pinocembrin. However, the reference molecule has binding energy of -7,28 kcal/mol and 4,65 M. In conclusion, the high potential of flavonoids in ethanolic propolis extracts to bind to ACE II receptors indicates that this natural bee product has high potential for Covid- 19 treatment, but this needs to be supported by experimental studies.
THE PROTOTYPIC NUTRITIONAL ASSESSMENT AND THE PARSING OF THE NUTRITIONAL CRITICAL CONTROL POINTS (NCCP) IN ORTHOPEDICS
Authors: Briguglio Matteo , Banfi Giuseppe , Vitale Jacopo , Sirtori Paolo , Perazzo Paolo
Published: April 2020

We presented preliminary results of an ongoing trial comprehensively evaluating older adults undergoing prosthetic hip surgery from a biochemical, dietetic, nutritional, and functional perspective.
Hereditary syndromal and nonsyndromal forms of primary hyperparathyroidism
Authors: Gorbacheva Anna M. , Eremkina Anna K. , Mokrysheva Natalya G.
Published: April 2020

Primary hyperparathyroidism is a common disorder of mineral homeostasis, characterized by overproduction of parathyroid hormone and upper normal or elevated calcium levels due to hyperplasia or a tumor of parathyroid gland. 9095% of cases of primary hyperparathyroidism are sporadic, while hereditary genetic forms occur in 510% of all cases. Primary hyperparathyroidism as the component of hereditary syndromes can present in various clinical forms (asymptomatic, symptomatic), can be associated with other endocrine or non-endocrine diseases, and require special approaches to treatment. Given that primary hyperparathyroidism is one of the most common components of these syndromes, it can be used as an important diagnostic tool in identifying affected families. This review is devoted to modern ideas about the clinical course and genetic characteristics of hereditary variants of primary hyperparathyroidism and the diagnostic and treatment algorithms recommended today. The review considers primary hyperparathyroidism as a component of hereditary syndromes including multiple endocrine neoplasias types 1, 2A and 4 and syndrome of hyperparathyroidism with a jaw tumor. Also non-syndromic hereditary forms are descripted, such as familial isolated hyperparathyroidism, familial hypocalciuric hypercalcemia, and severe neonatal primary hyperparathyroidism.
Optical telescope with Cassegrain metasurfaces
Authors: Liu Xuan , Deng Junhong , Li King Fai , Jin Mingke , Tang Yutao , Zhang Xuecai , Cheng Xing , Wang Hong , Liu Wei , Li Guixin
Published: April 2020

The Cassegrain telescope, made of a concave primary mirror and a convex secondary mirror, is widely utilized for modern astronomical observation. However, the existence of curved mirrors inevitably results in bulky configurations. Here, we propose a new design of the miniaturized Cassegrain telescope by replacing the curved mirrors with planar reflective metasurfaces. The focusing and imaging properties of the Cassegrain metasurface telescopes are experimentally verified for circularly polarized incident light at near infrared wavelengths. The concept of the metasurface telescopes can be employed for applications in telescopes working at infrared, Terahertz, and microwave and even radio frequencies.
Visible-wavelength pulsed lasers with low-dimensional saturable absorbers
Authors: Zou Jinhai , Ruan Qiujun , Zhang Xiaojin , Xu Bin , Cai Zhiping , Luo Zhengqian
Published: April 2020

The recent renaissance in pulsed lasers operating in the visible spectral region has been driven by their significant applications in a wide range of fields such as display technology, medicine, microscopy, material processing, and scientific research. Low-dimensional nanomaterials as saturable absorbers are exploited to create strong nonlinear saturable absorption for pulse generation at visible wavelengths due to their absorption peaks located in visible spectral region. Here we provide a detailed overview of visible-wavelength pulsed lasers based on low-dimensional nanomaterials, covering the optical properties and various integration strategies of these nanomaterials saturable absorbers, and their performance from solid-state as well as fiber pulsed lasers in the visible spectral range. This emerging application domain will undoubtedly lead to the rapid development of visible pulsed lasers.