bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Customer Churn via Service Mode Control
Authors: Kanoria Yash , Lobel Ilan , Lu Jiaqi
Published: July 2023

We introduce a novel stochastic control model for the problem of a service firm interacting over time with one of its customers who probabilistically churns depending on the customer’s satisfaction. The firm has two service modes available, and they determine the drift and volatility of the Brownian reward process. The firm’s objective is to maximize the rewards generated over the customer’s lifetime. Meanwhile, the customer might churn probabilistically if the customer’s satisfaction, modeled as an Orstein–Uhlenbeck process controlled by the firm’s service mode, is below a certain threshold. We build upon Markov processes with spatial delay to solve this problem, and we explicitly characterize the firm’s optimal policy, which is either myopic or a sandwich policy. A sandwich policy is one in which the firm deploys the service mode with inferior reward rate when the customer satisfaction level is in a specific interval near the satisfaction threshold and uses the myopically optimal service mode for all other satisfaction levels. Specifically, we find that the firm should use the safe service mode when the customer is marginally satisfied and the risky service mode when the customer is marginally unsatisfied. We find numerically that the customer lifetime value under the optimal policy is large relative to that under the myopic policy. Our results are robust to a variety of alternative model specifications.

Funding: J. Lu gratefully acknowledges financial support from Natural Science Foundation of China (NSFC) [Project 72192805].

Supplemental Material: The online appendix is available at https://doi.org/10.1287/moor.2021.0179 .
Probabilistic Bounds on the k-Traveling Salesman Problem and the Traveling Repairman Problem
Authors: Blanchard Moïse , Jacquillat Alexandre , Jaillet Patrick
Published: July 2023

The [Formula: see text]traveling salesman problem (k-TSP) seeks a tour of minimal length that visits a subset of [Formula: see text] points. The traveling repairman problem (TRP) seeks a complete tour with minimal latency. This paper provides constant-factor probabilistic approximations of both problems. We first show that the optimal length of the k-TSP path grows at a rate of [Formula: see text]. The proof provides a constant-factor approximation scheme, which solves a TSP in a high-concentration zone, leveraging large deviations of local concentrations. Then, we show that the optimal TRP latency grows at a rate of [Formula: see text]. This result extends the classic Beardwood–Halton–Hammersley theorem to the TRP. Again, the proof provides a constant-factor approximation scheme, which visits zones by decreasing order of probability density. We discuss practical implications of this result in the design of transportation and logistics systems. Finally, we propose dedicated notions of fairness—randomized population-based fairness for the k-TSP and geographic fairness for the TRP—and give algorithms to balance efficiency and fairness.

Funding: This work was partly supported by [Grant ONR N00014-18-1-2122] and the Singapore National Research Foundation through the Singapore–Massachusetts Institute of Technology Alliance for Research and Technology Centre for Future Urban Mobility.

Supplemental Material: The e-companion is available at https://doi.org/10.1287/moor.2021.0286 .
An Iterated Local Search Metaheuristic for the Capacitated Demand-Driven Timetabling Problem
Authors: Schettini Tommaso , Gendreau Michel , Jabali Ola , Malucelli Federico
Published: July 2023

In many major cities, metro lines constitute the backbone of urban public transport, providing an efficient and greener alternative to private mobility. An important feature that distinguishes metro lines from other public transport means, such as buses, is that metros are typically tightly resource constrained. The trains operating on a particular line are often specifically fitted for that line, making any capacity expansion extremely costly and time-consuming. Therefore, researchers and operators alike are seeking ways to make better use of existing resources. One possible way of doing so is by adapting timetables to forecasted demand while accounting for limited vehicle capacities. Thus, we consider a demand-driven nonperiodic timetabling problem for a two-directional metro line that minimizes the total passenger waiting time through the efficient scheduling of the available trains. Considering that passengers board trains using a well-mixed policy, we explicitly account for train capacities on a moment-to-moment basis. Last, we consider that trains are allowed to short turn. In this respect, we assume that trains must pass by a given station before short turning and are only allowed to idle after having short turned. We devise a polynomial time algorithm for assessing the total passenger waiting time generated by a given timetable and an effective lower bound that is evaluated in linear time. These are used in a variable neighborhood search algorithm, which is embedded in an iterated local search metaheuristic. Classical local search-based neighborhoods are not effective for our problem because they do not explicitly handle the vehicle scheduling decisions. To handle this challenge, we proposed three tailored neighborhoods. We validate our heuristic on the uncapacitated version of the problem. Considering a benchmark of 48 artificial instances with up to 20 stations, our heuristic achieved an average gap of 0.67% and found eight new best solutions. We also validated our heuristic on three sets of instances based on realistic lines from Milan, Madrid, and Beijing. Furthermore, we demonstrate the operational advantages of our optimized timetables in the capacitated version of the problem by comparing them with regular timetables and with exact solutions obtained for the uncapacitated case. Furthermore, we conduct a sensitivity analysis with respect to the capacity of the trains and investigate the impact of a priority boarding policy.

Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2022.0271 .
The Pedagogical Role of the Primary-School Headteacher: Insights From Greece
Authors: Alexopoulos Nikolaos , Babalis Thomas , Tsoli Konstantina , Delioridou Stavroula
Published: July 2023

The pedagogical and didactic guidance of teachers has been linked, in the relevant literature, to the school management’s adoption of the model of pedagogical leadership as well as to the assurance of a series of factors that influence it. This study aims at investigating the pedagogical role of the principal in Greek primary schools. Data were collected through an anonymous questionnaire completed by 133 Greek primary school head teachers. Results show that head teachers consider that their pedagogical role has mainly to do with the pedagogical climate, psychosocial and pedagogical guidance of the school unit. Additionally, the research results show that head teachers carry out their pedagogical role cooperating and communicating mainly with the members of the educational community of the school. Another noteworthy finding of the present study is that the factors that support head teachers in their pedagogical leadership role, are hard to exist in hierarchical educational realities such as Greece. The originality of the paper draws attention to the school's socio-economic environment, which significantly influences school leadership. Conclusions on the implications of the study are made and directions for future research are suggested.
Evaluation of Low-Cost UV-Vis Spectroscopy for Measuring Nitrate Using Synthetic Water Samples
Authors: Carter Joe Barrett , Sarkees Ashley , Singh A. , Bean Eban
Published: July 2023

Highlights

A novel low-cost, modular spectroscopy system is compared to a standard system using synthetic samples, principal component analysis, and partial least squares regression.

The information contained in the data produced by the two systems is similar according to principal component analysis.

The low-cost system was able to accurately predict nitrate concentrations in concentrated and diluted samples using partial least squares regression.

The methodology could be applied to water quality analysis in agriculture and water resources management.

Abstract. Water quality data collection is an essential component of water systems management. For instance, the effective management of nutrients in hydroponic systems is necessary for maximizing yields efficiently and sustainably. Additionally, nutrients in natural and engineered waterbodies must be monitored to ensure they are meeting the required chemical characteristics for their ecological and social functions. However, conventional water quality data collection methods place limitations on water systems management due to their high resource requirements. Nitrate (NO3) is a major nutrient in ecological and agricultural systems, which can be reliably measured with ultraviolet-visible (UV-Vis) spectroscopy, a highly established technique for water quality analysis. The goal of this research was to evaluate a novel, low-cost, modular UV-Vis spectroscopy setup (GatorSpec) for the measurement of NO3 concentration in chemically complex solutions. UV-Vis absorbance of synthetic samples was measured using the GatorSpec and a commonly used bench-top laboratory spectroscopy system, the NanoDrop2000C. These data were analyzed using principal component analysis (PCA) to compare the spectral data produced by each system and partial least squares (PLS) regression to compare their ability to predict NO3 concentration. Results showed that data from both measurement systems were similar, indicating that the low-cost GatorSpec provided similar measurement accuracy to that of the laboratory reference system, the NanoDrop2000C. The PLS results revealed that for the diluted samples, the models derived from both systems were very good at predicting NO3 concentration. With these outcomes, it can be concluded that the GatorSpec is effective at measuring NO3 concentration in complex solutions and is comparable in performance to that of the NanoDrop2000C. In the future, this low-cost setup could be used to manage NO3 concentrations more efficiently in various applications such as hydroponic plant production, environmental monitoring, and stormwater treatment, which, in turn, could reduce the economic and environmental costs of these systems. Keywords: Low-cost, Synthetic samples, Ultraviolet-visible absorption spectroscopy, Water quality.
Cost Optimization and Reliability Parameter Extraction of a Complex Engineering System
Authors: Kumar Anuj , Pant Sangeeta , Ram Mangey
Published: July 2023

Nowadays, the transformation of the various energy system is the core objective of the dedicated sustainable development goal related to energy sustainable world within the new United Nations development agenda. Different nuclear regulatory authorities around the globe, sets Technical Specifications (TSs) for ensuring the human and environmental safety of various highly volatile and complex Nuclear Power Generation Plants (NPGPs). TSs define numerous measures and limitations related to safety and sustainability that must be followed by all NPGPs around the world. Reliability, availability and cost components associated with a NPGPs form important bases for the setting of TSs. In this work, a framework based on few recent metaheuristics like Cuckoo Search Algorithm (CSA), Grey Wolf Optimizer (GWO), Hybrid PSO GWO algorithm (HPSOGWO) has been presented for cost optimization and reliability parameter extraction of a complex engineering system named Heat Removal System (HRS) of a nuclear power generation plant safety system (NPGPSS). A multi-criteria decision-making (MCDM) method named Weighted-Sum Method (WSM) has also been employed for prioritizing the available metaheuristics based on available beneficial and non-beneficial criteria’s.
Identifying Optimal Locations for Hardwood CLT Plants in Tennessee: Application of a Spatially Explicit Framework
Authors: Adhikari Ram K. , Poudyal Neelam C. , Brandeis Consuelo , Nepal Prakash
Published: July 2023

The prospect of using mass timber products, such as cross-laminated timber (CLT), for building material has increased in recent years because of the advantage of these products over their substitutes in terms of structural rigidity, cost efficiency, and climate benefits. However, the American National Standard developed for CLT currently applies to softwood only. With the expected increase in the market for CLT, the supply chain needs to address the projected rise in demand for hardwood as well. Promoting the production of hardwood mass timber like CLT requires studying the feasibility of quality hardwood lumber supply and identifying the optimal locations for investing capital in CLT manufacturing plants. By presenting a case from Tennessee, this study provides a spatially explicit framework to use a variety of factors such as transportation networks, proximity to sawmills, sawmill capacity, and roundwood supply to identify optimal CLT plant locations. Specifically, fuzzy multicriteria analysis was used to identify potential locations, which provided inputs for a location-allocation model to identify optimal locations for CLT plants. Among the several potential locations, three optimal locations suitable for CLT plants were identified with 12,504 thousand cubic feet (MCF) annual production potential of CLT panels in Tennessee. Although increasing transportation distance for lumber procurement would increase CLT production capacity, it would also result in increased lumber supply costs. Potential investors and regional planners interested in using hardwood forest products can benefit from these findings to locate suitable sites for new investment.
The intonation of Spanish spoken in Bucaramanga (Colombia)
Authors: Roberto Yeimy J.
Published: July 2023

This paper presents the characteristics of the intonation of Spanish spoken in Bucaramanga, Colombia, a variety considered as “strong and rude”. Spontaneous, semi-spontaneous and read utterances from four participants were analysed acoustically. After stylisation with MOMEL, the data was tagged according to the Sp_ToBI system, within the Autosegmental-Metrical model. The declarative, interrogative, and exhortative contours were compared with the intonational inventories available for Spanish. The results confirm prior dialectal boundaries based on lexical data and supports the dichotomy between  coastal and mountain varieties in the dialects of Spanish spoken in Colombia.
The realisation and phonetic features of the glottal stop in Bahdini Kurdish
Authors: Hasan Aveen Mohammed , Mohammed Fakhir Omar
Published: July 2023

In Bahdini Kurdish (henceforth, BK), the realisation and the phonetic features of the glottal stop (GS) has not been extensively investigated and there is a debate about its phonemic status. In one hand, it is considered a phoneme that occurs only in a word-initial position. On the other hand, it is not con- sidered a phoneme but optionally produced at the beginning of vowel-initial words and does not affect meaning. The study aims at identifying the realisation of this sound experimentally, analyses its acous- tic features and whether it is affected by parameters such as vowel type, vowel position in the word and stress. The study is based on read speech produced by 10 BK native speakers. Then it is analysed phonetically using Praat to identify the presence/absence of the GS. Then the number of occurrences of the GSs are compared across vowel types, vowel position and stress. The results show that the GS is an epenthetic sound in BK that is inserted by the speakers to avoid onsetless syllables and to avoid vowel clusters. Different phonetic variations of the sound are realized in BK: A clear closure of the glottal stop, intermittent vocal folds vibrations during the GS closure, vocal folds vibrations start sim- ultaneously with the GS release. It appears not to be affected by stress but by position, as it is found more medially in V+V contexts than initially, and vowel quality as it is produced more before low vowels than non-low vowels.
Associations Between Different Types of Housing Insecurity and Future Emergency Department Use Among a Cohort of Emergency Department Patients
Authors: Routhier Giselle , Mijanovich Tod , Schretzman Maryanne , Sell Jessica , Gelberg Lillian , Doran Kelly M.
Published: July 2023

Abstract: Housing insecurity can take multiple forms, such as unaffordability, crowding, forced moves, multiple moves, and homelessness. Existing research has linked homelessness to increased emergency department (ED) use, but gaps remain in understanding the relationship between different types of housing insecurity and ED use. In this study, we examined the association between different types of housing insecurity, including detailed measures of homelessness, and future ED use among a cohort of patients initially seen in an urban safety-net hospital ED in the United States between November 2016 and January 2018. We found that homelessness was associated with a higher mean number of ED visits in the year post-baseline. Other measures of housing insecurity (unaffordability, crowding, forced moves, and multiple moves) were not associated with greater ED use in the year post-baseline in multivariable models. We also found that only specific types of homelessness, primarily unsheltered homelessness, were associated with increased ED use.
Promoting Access to Dental Care in a Developing Caribbean Nation, Post-disaster
Authors: Modha Bhaven
Published: July 2023

Abstract: In September 2017, Hurricane Irma struck several Caribbean islands, which suffered catastrophic damage. Anguilla, the most northerly of the Caribbean's Leeward Islands, a developing nation, experienced devastating damage to its social, physical, political, and economic infrastructures. Anguilla's longstanding Dental Unit, a public sector health care facility, was among the services that suffered irreparable destruction. Hurricane Irma's debilitating impact on a developing nation and its citizens' livelihoods exacerbated existing challenges in dental care, and created barriers to access. As part of the rehabilitation process, it was essential to promote access to dental care. This commentary shares examples of some practical and economical approaches that were employed: providing direct access to dental therapists, offering dedicated emergency and routine care appointments, delivering oral health campaigns, partaking in community health fairs, and social media engagement. The commentary also considers future approaches that could be beneficial.
On the Construction of National Symbol in S. Y. Abramovitsh's Susati
Authors: Burns Rhona
Published: July 2023

Abstract: This paper focuses on the way national symbol is constructed in the Hebrew novel Susati , which was written as a national allegory at around the turn of the twentieth century. The paper sheds new light on the Jewishness of the chosen aesthetic representation. The paper argues that Abramovitsh's symbolic method accentuates a new understanding of Jewish national existence that is represented through the behavioral constructions that develop between the novel's human protagonist and the animal protagonist—the mare—as well as between these two and the devil. This elaborate and complicated literary representation mirrors the chaotic reality experienced by many Jews in early twentieth-century Eastern Europe.
Unleashing the power of optical attenuation coefficients to facilitate segmentation strategies in OCT imaging of age-related macular degeneration: perspective
Authors: Rosenfeld Philip J. , Cheng Yuxuan , Shen Mengxi , Gregori Giovanni , Wang Ruikang K.
Published: July 2023

The use of optical attenuation coefficients (OAC) in optical coherence
tomography (OCT) imaging of the retina has improved the segmentation
of anatomic layers compared with traditional intensity-based
algorithms. Optical attenuation correction has improved our ability to
measure the choroidal thickness and choroidal vascularity index using
dense volume scans. Algorithms that combine conventional
intensity-based segmentation with depth-resolved OAC OCT imaging have
been used to detect elevations of the retinal pigment epithelium (RPE)
due to drusen and basal laminar deposits, the location of
hyperpigmentation within the retina and along the RPE, the
identification of macular atrophy, the thickness of the outer retinal
(photoreceptor) layer, and the presence of calcified drusen. OAC OCT
algorithms can identify the risk-factors that predict disease
progression in age-related macular degeneration.
Super-resolution image projection using a diffractive optical decoder
Authors: Işıl Çağatay , Mengu Deniz , Zhao Yifan , Tabassum Anika , Li Jingxi , Luo Yi , Jarrahi Mona , Ozcan Aydogan
Published: July 2023

We report a diffractive super-resolution image display framework consisting of a digital encoder and an all-optical decoder to synthesize/project high-resolution images at an output plane using a low-resolution input light-modulator.
Combination of Optical Phase Conjugation and Advanced Pruning Techniques to reduce the Computational Complexity of Neural Network-Based Equalisers
Authors: Ron Diego Argüello
Published: July 2023

Combining midlink optical phase conjugation and different pruning techniques is proposed to develop low complexity complex-valued neural networks based equalisers in a PDM 28 Gbaud 64 QAM transmission over 400km of SSMF.
Three-dimensional refractive index estimation based on deep-inverse non-interferometric optical diffraction tomography (ODT-Deep)
Authors: Bazow Brad , Phan Thuc , Raub Christopher B. , Nehmetallah George
Published: July 2023

Optical diffraction tomography (ODT) solves an inverse scattering problem to obtain label-free, 3D refractive index (RI) estimation of biological specimens. This work demonstrates 3D RI retrieval methods suitable for partially-coherent ODT systems supported by intensity-only measurements consisting of axial and angular illumination scanning. This framework allows for access to 3D quantitative RI contrast using a simplified non-interferometric technique. We consider a traditional iterative tomographic solver based on a multiple in-plane representation of the optical scattering process and gradient descent optimization adapted for focus-scanning systems, as well as an approach that relies solely on 3D convolutional neural networks (CNNs) to invert the scattering process. The approaches are validated using simulations of the 3D scattering potential for weak phase 3D biological samples.
Fiber-tip spintronic terahertz emitters
Authors: Paries Felix , Tiercelin Nicolas , Lezier Geoffrey , Vanwolleghem Mathias , Selz Felix , Syskaki Maria-Andromachi , Kammerbauer Fabian , Jakob Gerhard , Jourdan Martin , Kläui Mathias , Kaspar Zdenek , Kampfrath Tobias , Seifert Tom S. , von Freymann Georg , Molter Daniel
Published: July 2023

Spintronic terahertz emitters promise terahertz sources with an unmatched broad frequency bandwidth that are easy to fabricate and operate, and therefore easy to scale at low cost. However, current experiments and proofs of concept rely on free-space ultrafast pump lasers and rather complex benchtop setups. This contrasts with the requirements of widespread industrial applications, where robust, compact, and safe designs are needed. To meet these requirements, we present a novel fiber-tip spintronic terahertz emitter solution that allows spintronic terahertz systems to be fully fiber-coupled. Using single-mode fiber waveguiding, the newly developed solution naturally leads to a simple and straightforward terahertz near-field imaging system with a 90%-10% knife-edge-response spatial resolution of 30 µm.
Continuous-wave terahertz quantum cascade microlaser arrays operating on various bound states in the continuum
Authors: Bai Hongzhou , Liu Guowen , Wang Kai , Chang Gaolei , Zang Shanzhi , Tan Cheng , Gan Lianghua , Zhang Yueheng , He Li , Xu Gangyi
Published: July 2023

We report on the continuous-wave (CW) operation of 1D terahertz quantum cascade (THz QC) microlaser arrays working on various bound states in the continuum (BICs). We first created a quasi-BIC state by breaking the inversion symmetry of the microlaser array, which enables flexible control of the radiation efficiency. The optimized multi-periods array exhibits single-mode emission with the maximum output power of 21 mW (at 30 K), and the maximum operation temperature (Tcw) of 45 K. To further increase Tcw, we created a hybrid-BIC state by hybridizing a quasi-BIC generated in a few-periods array and a high-Q surface plasmon polariton mode formed in an unbiased array. The hybridization minimizes the pumping area with no obvious degradation of the threshold current density. The reduced pumping area, together with the discrete distribution of microlasers, significantly decreases the device thermal resistance. Such scheme improves the Tcw up to 79 K with a low beam divergence of 17°×17°, and the output power remains 3.4 mW at 20 K. Our work provides a novel solution to control the output power, the operating temperature, and the beam quality of THz QC lasers in CW mode.
Inverse design of omnidirectional coherent absorbers for optical power beaming applications
Authors: Markowitz Matthew , Vela Erina , Jahromi Ali K. , Tamargo Maria C. , Kuskovsky Igor L. , Miri Mohammad-Ali
Published: July 2023

An efficient photovoltaic power converter is a critical element in laser power beaming systems for maximizing the end-to-end power transfer efficiency while minimizing beam reflections from the receiver for safety considerations. We designed a multilayer absorber that can efficiently trap monochromatic light from broad incident angles. The proposed design is built on the concept of a one-way coherent absorber with inverse-designed aperiodic multilayer front- and back-reflectors that enable maximal optical absorption in a thin-film photovoltaic material for broad angles. We argue that the broad bandwidth is achieved through an optimization search process that automatically engineers the modal content of the cavity to create multiple overlapping resonant modes at the desired angle or frequency range. A realistic design is provided based on GaAs thin films with inverse-designed multilayer binary AlAs/AlGaAs mirrors. The proposed device can pave the way for efficient optical power beaming systems.
Highly sensitive torsion sensor based on a coupled optoelectronic oscillator incorporating nonlinear polarization rotation
Authors: Feng Danqi , Tang Yangxu , Liu Yuwei , Deng Ming
Published: July 2023

We propose and demonstrate a new, to the best of our knowledge, technique to implement a high-speed and highly sensitive torsion sensor based on a coupled optoelectronic oscillator (COEO) incorporating nonlinear polarization rotation (NPR). The COEO consists of a mode-locked laser loop and an OEO loop. In the laser loop, the NPR effect effectively induces intensity- and wavelength-dependent loss, which acts as a Lyot birefringent fiber filter. When twisting the polarization-maintaining fiber (PMF), the transmission of the filter varies as well as the laser output wavelength. In the OEO loop, the optical source is provided by the output signal of the mode-locked laser. The variation in the optical carrier wavelength changes the time delay and the oscillation frequency of the OEO loop. The oscillation frequency shift is a linear function of the twist angle. Sensitivities of −60.006 Hz/deg over 360° for a 48 cm PMF and −180.996 Hz/deg over 92° for a 22 cm PMF are achieved.
Fabrication of a multilevel Fresnel axicon deep in fused silica by femtosecond laser machining
Authors: Stankevič Valdemar , Karosas Jonas , Gečys Paulius
Published: July 2023

This manuscript presents a simple approach to the manufacturing and optimization of a multilevel phase-only diffractive conical lens (Fresnel axicon or “fraxicon”). The method for recording deep type I modifications in fused silica was established and its ability proven. We showed the prospects and limitations of elements processed using this method. The fine and advanced parameters optimization allowed us to get a compensation mechanism for almost uniform refractive index change for each separate layer. The maximum diffraction efficiency of the fraxicon for a wavelength of 515 nm was ∼80%. The measured Bessel beam depth of field was compared with commercially available conical lens axicons and showed good agreement.
Plasmon-enhanced fluorescence of gold nanoparticle/graphene quantum dots for detection of Cr3+ ions
Authors: Chen You-Long , Hu Yi-Hua , Yang Xing , Gu You-Lin , Wang Xin-Yu , Xia Yu-Hao , Zhang Xin-Yuan , Zhang Yu-Shuang
Published: July 2023

Graphene quantum dots (GQDs), fascinating semiconductors with stable photoluminescence (PL), have important potential applications in the fields of biology, medicine, and new semiconductor devices. However, it is still challenging to overcome the weak PL intensity. Here, we report a strategy for selective resonance enhancement of GQD fluorescence using gold nanoparticles (AuNPs) as plasmas. Interestingly, the addition of low concentration AuNP makes AuNP/GQDs exhibit significant fluorescence enhancement of 2.67 times in the visible range. The addition of high concentration AuNP leads to the formation of an excitation peak at 421 nm and selectively enhances certain radiation modes. We concluded that the main reason for the selective enhancement of PL intensity in high concentration AuNP is the transfer of generous hot electrons at high energy states from AuNP to GQD and relaxation to the ground state. The electron resonance of low concentration AuNP transfers to GQD and relaxes to lower energy levels, exhibiting an overall enhancement of PL intensity. We apply it for detection of the heavy metal ion Cr3+, and verify that it has a correlation coefficient of 97.36%. We believe AuNP/GQDs can be considered excellent candidates for heavy metal detection and high fluorescence bio-imaging.
Spatiotemporally reconfigurable light in degenerate laser cavities
Authors: Bartolo A. , Vigne N. , Marconi M. , Beaudoin G. , Le Gratiet L. , Pantzas K. , Sagnes I. , Garnache A. , Giudici M.
Published: July 2023

We show that a III-V semiconductor vertical external-cavity surface-emitting laser (VECSEL) can be engineered to generate light with a customizable spatiotemporal structure. Temporal control is achieved through the emission of temporal localized structures (TLSs), a particular mode-locking regime that allows individual addressing of the pulses traveling back and forth in the cavity. The spatial profile control relies on a degenerate external cavity, and it is implemented due to an absorptive mask deposited onto the gain mirror that limits the positive net gain within two circular spots in the transverse section of the VECSEL. We show that each spot emits spatially uncorrelated TLSs. Hence, the spatiotemporal structure of the light emitted can be shaped by individually addressing the pulses emitted by each spot. Because the maximum number of pulses circulating in the cavity and the number of positive net-gain spots in the VECSEL can be increased straightforwardly, this result is a proof of concept of a laser platform capable of handling light states of scalable complexity. We discuss applications to three-dimensional all-optical buffers and to multiplexing of frequency combs that share the same laser cavity.
Higher-order exceptional points in waveguide-coupled microcavities: perturbation induced frequency splitting and mode patterns
Authors: Kullig Julius , Grom Daniel , Klembt Sebastian , Wiersig Jan
Published: July 2023

Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian coalesce. Especially, the robust construction of higher-order exceptional points with more than two degenerate eigenfrequencies and eigenstates is challenging but yet worthwhile for applications. In this paper, we reconsider the formation of higher-order exceptional points through waveguide-coupled microring cavities and asymmetric backscattering. In this context, we demonstrate the influence of perturbations on the frequency splitting of the system. To generate higher-order exceptional points in a simple and robust way, a mirror-induced asymmetric backscattering approach is used. In addition to the exceptional-point enhanced sensing capabilities of such systems, also a cavity-selective sensitivity is achieved for particle sensing. The results are motivated by an effective Hamiltonian description and verified by full numerical simulations of the dielectric structure.
Implications of differential size-scaling of cell-cycle regulators on cell size homeostasis
Authors: Ji Xiangrui , Lin Jie
Published: July 2023

Accurate timing of division and size homeostasis is crucial for cells. A potential mechanism for cells to decide the timing of division is the differential scaling of regulatory protein copy numbers with cell size. However, it remains unclear whether such a mechanism can lead to robust growth and division, and how the scaling behaviors of regulatory proteins influence the cell size distribution. Here we study a mathematical model combining gene expression and cell growth, in which the cell-cycle activators scale superlinearly with cell size while the inhibitors scale sublinearly. The cell divides once the ratio of their concentrations reaches a threshold value. We find that the cell can robustly grow and divide within a finite range of the threshold value with the cell size proportional to the ploidy. In a stochastic version of the model, the cell size at division is uncorrelated with that at birth. Also, the more differential the cell-size scaling of the cell-cycle regulators is, the narrower the cell-size distribution is. Intriguingly, our model with multiple regulators rationalizes the observation that after the deletion of a single regulator, the coefficient of variation of cell size remains roughly the same though the average cell size changes significantly. Our work reveals that the differential scaling of cell-cycle regulators provides a robust mechanism of cell size control.
Using model-based geostatistics for assessing the elimination of trachoma
Authors: Sasanami Misaki , Amoah Benjamin , Diori Adam Nouhou , Amza Abdou , Souley Abdoul Salam Youssoufou , Bakhtiari Ana , Kadri Boubacar , Szwarcwald Célia L. , Ferreira Gomez Daniela Vaz , Almou Ibrahim , Lopes Maria de Fátima Costa , Masika Michael P. , Beidou Nassirou , Boyd Sarah , Harding-Esch Emma M. , Solomon Anthony W. , Giorgi Emanuele
Published: July 2023

Background

Trachoma is the commonest infectious cause of blindness worldwide. Efforts are being made to eliminate trachoma as a public health problem globally. However, as prevalence decreases, it becomes more challenging to precisely predict prevalence. We demonstrate how model-based geostatistics (MBG) can be used as a reliable, efficient, and widely applicable tool to assess the elimination status of trachoma.

Methods

We analysed trachoma surveillance data from Brazil, Malawi, and Niger. We developed geostatistical Binomial models to predict trachomatous inflammation—follicular (TF) and trachomatous trichiasis (TT) prevalence. We proposed a general framework to incorporate age and gender in the geostatistical models, whilst accounting for residual spatial and non-spatial variation in prevalence through the use of random effects. We also used predictive probabilities generated by the geostatistical models to quantify the likelihood of having achieved the elimination target in each evaluation unit (EU).

Results

TF and TT prevalence varied considerably by country, with Brazil showing the lowest prevalence and Niger the highest. Brazil and Malawi are highly likely to have met the elimination criteria for TF in each EU, but, for some EUs, there was high uncertainty in relation to the elimination of TT according to the model alone. In Niger, the predicted prevalence varied significantly across EUs, with the probability of having achieved the elimination target ranging from values close to 0% to 100%, for both TF and TT.

Conclusions

We demonstrated the wide applicability of MBG for trachoma programmes, using data from different epidemiological settings. Unlike the standard trachoma prevalence survey approach, MBG provides a more statistically rigorous way of quantifying uncertainty around the achievement of elimination prevalence targets, through the use of spatial correlation. In addition to the analysis of existing survey data, MBG also provides an approach to identify areas in which more sampling effort is needed to improve EU classification. We advocate MBG as the new standard method for analysing trachoma survey outputs.
Spatial distribution of Glossina morsitans (Diptera: Glossinidae) in Zambia: A vehicle-mounted sticky trap survey and Maxent species distribution model
Authors: Muyobela Jackson , Pirk Christian W. W. , Yusuf Abdullahi A. , Sole Catherine L.
Published: July 2023

Background

Tsetse-transmitted African trypanosomiasis is a debilitating and fatal disease of humans and livestock if left untreated. While knowledge of the spatial distribution patterns of tsetse is essential for the development of risk-based vector control strategies, existing distribution maps in Zambia are more than 40 years old and were based on coarse spatial resolution data. The recently developed vehicle-mounted sticky trap (VST) provides an alternative sampling device to aid in updating existing distribution maps but has not been applied outside an experimental setting and is limited to motorable tracks. Therefore, the objective of the present study was to demonstrate the effectiveness of utilizing the VST for area-wide surveys of Glossina morsitans and to use the occurrence records to predict its spatial distribution in Zambia under current environmental conditions using Maxent.

Methodology/Principal findings

Two-sided all-blue VST baited with butanone and 1-octen-3-ol was used to survey 692 and 1020 km of transect routes in G. m. centralis Machado and G. m. morsitans Westwood previously published distribution in Zambia. Maxent species distribution technique was used to predict the potential distribution of the two subspecies using current climatic and environmental data which was then compared to the historical distribution. A total of 15,602 tsetse were captured with G. m. morsitans (58%) being the most abundant. G. m. centralis and G. pallidipes Austin represented 39 and 2% of the catch respectively, and G. brevipalpis Newstead was also detected. The predicted potential distribution for G. m. centralis was 80,863 km2 while that of G. m. morsitans was 70,490 km2 representing a 47 and 29% reduction compared to their historical distributions, respectively.

Conclusion/Significance

The VST is effective for sampling G. morsitans outside experimental settings and is recommended for use as an additional tsetse survey tool. The spatial distribution of G. morsitans in Zambia has reduced by 101,051 km2 due to temperature and land cover changes.
Discrete choice experiment versus swing-weighting: A head-to-head comparison of diabetic patient preferences for glucose-monitoring devices
Authors: Whichello Chiara , Smith Ian , Veldwijk Jorien , de Wit G. Ardine , Rutten- van Molken Maureen P. M. H. , de Bekker-Grob Esther W.
Published: July 2023

Introduction

Limited evidence exists for how patient preference elicitation methods compare directly. This study compares a discrete choice experiment (DCE) and swing-weighting (SW) by eliciting preferences for glucose-monitoring devices in a population of diabetes patients.

Methods

A sample of Dutch adults with type 1 or 2 diabetes (n = 459) completed an online survey assessing their preferences for glucose-monitoring devices, consisting of both a DCE and a SW exercise. Half the sample completed the DCE first; the other half completed the SW first. For the DCE, the relative importance of the attributes of the devices was determined using a mixed-logit model. For the SW, the relative importance of the attributes was based on ranks and points allocated to the ‘swing’ from the worst to the best level of the attribute. The preference outcomes and self-reported response burden were directly compared between the two methods.

Results

Participants reported they perceived the DCE to be easier to understand and answer compared to the SW. Both methods revealed that cost and precision of the device were the most important attributes. However, the DCE had a 14.9-fold difference between the most and least important attribute, while the SW had a 1.4-fold difference. The weights derived from the SW were almost evenly distributed between all attributes.

Conclusions

The DCE was better received by participants, and generated larger weight differences between each attribute level, making it the more informative method in our case study. This method comparison provides further evidence of the degree of method suitability and trustworthiness.
Financial investment trust mechanism based on smart contract
Authors: Xiong Wei , Wan Danping
Published: July 2023

In this paper, a financial investment trust solution based on smart contract is proposed to solve the distrust problem in financial investment caused by information asymmetry. By utilizing the functional attributes of blockchain-based smart contracts, the financial investment trust mechanism is established. By operating this mechanism, the financial investment information is received, stored, and processed, and the information is sent to the nodes in the blockchain. By devising the algorithms of "requesting financial investment service", "successful financial investment", "product contract fraud arbitration" and "investment contract fraud arbitration", the financial investment trust mechanism is achieved. By presenting the algorithms and their invoking processes, smart contracts for the solution are written and debugged. Finally, the smart contracts are tested and validated. The smart contract source code is available in GitHub.
The criterion for dividing the surrounding rock EDZs of underground caverns based on the energy dissipation degree
Authors: Wang Xianliang , Zhang Jianhai , Qian Li , Yao Tianzhi , Mo Zuguo , He Jianhua , Zhang Ru , Zhao Changgui , Qiao Zanbo
Published: July 2023

An energy calculation parameter named the energy dissipation degree (RUd) is introduced based on the analysis of the energy dissipation mechanism and energy evolution characteristics during conventional triaxial tests of the granite of Shuangjiangkou. The deviatoric stress‒strain curve of rock can be divided into five stages using four stress thresholds (crack closure stress σcc, crack initiation stress σci, damage stress σcd and peak stress σp), which also correspond to the four RUd thresholds (RUdc, RUdi, RUdd and RUdp) on the energy dissipation degree–strain curve. A given stress threshold increases with increasing confining pressure; however, a given RUd threshold is basically stable under different confining pressures. Then, a new criterion for dividing the excavation damaged zones (EDZs) in the rock surrounding underground caverns based on the monotonically increasing characteristics of the energy dissipation degree‒axial strain relationship curve is proposed, and it allows for the classification of the surrounding rock into five types of zones through quantitative analysis of the RUd thresholds. Based on the criterion for dividing the EDZs of the surrounding rock mass of the underground cavern, the EDZs of the surrounding rocks of the underground cavern group of the Shuangjiangkou Hydropower Station are analyzed. The distribution characteristics of the EDZs of the rock surrounding underground caverns obtained by numerical simulation calculations based on RUd are basically the same as those obtained by in situ elastic wave tests. However, the RUd-based method for classifying the EDZs of the surrounding rock has the obvious advantage of being able to probe the boundaries of the undamaged zone (UDZ) of the surrounding rock more explicitly, while the method based on wave velocity testing is not sufficiently explicit. The damage zoning of the surrounding rock based on RUd can provide support design advice for the excavation of the surrounding rock, such as the support method, the length of the free section and anchor section of the prestressing anchor, etc.
Validation of robust radiobiological optimization algorithms based on the mixed beam model for intensity-modulated carbon-ion therapy
Authors: Yagi Masashi , Tsubouchi Toshiro , Hamatani Noriaki , Takashina Masaaki , Saruwatari Naoto , Minami Kazumasa , Wakisaka Yushi , Fujitaka Shinichiro , Hirayama Shusuke , Nihongi Hideaki , Hasegawa Azusa , Koizumi Masahiko , Shimizu Shinichi , Ogawa Kazuhiko , Kanai Tatsuaki
Published: July 2023

Currently, treatment planning systems (TPSs) that can compute the intensities of intensity-modulated carbon-ion therapy (IMCT) using scanned carbon-ion beams are limited. In the present study, the computational efficacy of the newly designed IMCT algorithms was analyzed for the first time based on the mixed beam model with respect to the physical and biological doses; moreover, the validity and effectiveness of the robust radiobiological optimization were verified. A dose calculation engine was independently generated to validate a clinical dose determined in the TPS. A biological assay was performed using the HSGc-C5 cell line to validate the calculated surviving fraction (SF). Both spot control (SC) and voxel-wise worst-case scenario (WC) algorithms were employed for robust radiobiological optimization followed by their application in a Radiation Therapy Oncology Group benchmark phantom under homogeneous and heterogeneous conditions and a clinical case for range and position errors. Importantly, for the first time, both SC and WC algorithms were implemented in the integrated TPS platform that can compute the intensities of IMCT using scanned carbon-ion beams for robust radiobiological optimization. For assessing the robustness, the difference between the maximum and minimum values of a dose–volume histogram index in the examined error scenarios was considered as a robustness index. The relative biological effectiveness (RBE) determined by the independent dose calculation engine exhibited a −0.6% difference compared with the RBE defined by the TPS at the isocenter, whereas the measured and the calculated SF were similar. Regardless of the objects, compared with the conventional IMCT, the robust radiobiological optimization enhanced the sensitivity of the examined error scenarios by up to 19% for the robustness index. The computational efficacy of the novel IMCT algorithms was verified according to the mixed beam model with respect to the physical and biological doses. The robust radiobiological optimizations lowered the impact of range and position uncertainties considerably in the examined scenarios. The robustness of the WC algorithm was more enhanced compared with that of the SC algorithm. Nevertheless, the SC algorithm can be used as an alternative to the WC IMCT algorithm with respect to the computational cost.