bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial distribution of the ethnomedicinal plant Aglaonema simplex at the Sakaerat Environmental Research Station, Northeastern Thailand
Authors: O-THONG NUTCHAPAT , TASEN WATTANACHAI , MAROD DOKRAK , THINKAMPHEANG SATHID , PHUMPHUANG WONGSATORN
Published: October 2024

Abstract. O-thong N, Tasen W, Marod D, Thinkampheang S, Phumphuang W. 2024. Spatial distribution of the ethnomedicinal plant Aglaonema simplex at the Sakaerat Environmental Research Station, Northeastern Thailand. Biodiversitas 25: 3043-3050. Aglaonema simplex Blume (Araceae) is an evergreen herbaceous plant used ornamentally and in traditional medicine. Although the usefulness of this plant has been widely studied and reported, its ecology remains poorly understood. In this study, we examined the effects of various environmental factors on the spatial distribution of A. simplex in a Dry Evergreen Forest (DEF) at the Sakaerat Environmental Research Station (SERS) in Northeastern Thailand. All individual plants were counted; their positions were recorded within a 16-ha Forest Dynamics Plot (FDP), and their distribution pattern was analyzed using Ripley's K function. The spatial distribution of A. simplex was determined using a generalized linear model that incorporated plant density and topographic and edaphic variables within the 16-ha study plot. We found a total of 11,232 A. simplex individuals with a density of 702 individuals ha-1, with a clumped distribution pattern. The modeling results showed that the spatial distribution of A. simplex was positively influenced by soil clay content, soil pH, exchangeable magnesium, and adult tree density; it was negatively influenced by sapling density and rocky outcrops. These findings contribute to the broader understanding of the ecological niche of A. simplex. They can be used to design integrated land management approaches that balance ecological conservation with economic development goals.
Life history traits of the gastropod-associated bacterivorous nematode Caenorhabditis brenneri (Nematoda: Rhabditida)
Authors: DALAN LOEL , TAÑAN VERONICA , DIANO MICHELLE ANNE , DEMAYO CESAR , TABELIN MYLAH , SUMAYA NANETTE HOPE
Published: October 2024

Abstract. Dalan L, Tañan V, Diano MA, Demayo C, Tabelin M, Sumaya NH. 2024. Life history traits of the gastropod-associated bacterivorous nematode Caenorhabditis brenneri (Nematoda: Rhabditida). Biodiversitas 25: 3106-3113. Caenorhabditis species are associated with decaying plant materials and invertebrates such as terrestrial gastropods. Few Caenorhabditis species have been studied regarding their ecology, genetics, development, and essential life history traits (LHT). In this study, we describe the life cycle of a free-living, wild-type, bacterivorous nematode, Caenorhabditis brenneri Sudhaus and Kiontke 2007, associated with the terrestrial slug Philippinella moellendorffi Collinge 1899 and account for the effects of food density and temperature on its population dynamics by employing the hanging drop technique. The bacterial food supply was sourced from the slug cadaver and identified as Alcaligenes faecalis (MT012081). C. brenneri was fed with varying bacterial densities (109 and 5×109 cells mL-1) and incubated at 20 and 25°C. The bacterial food density-temperature interaction was found to have no significant influence on the offspring production of C. brenneri. Moreover, the total fertility rate (TFR) and net reproductive rate (Ro) are higher in 109 cells mL-1 in both temperatures (TFR at 20°C: 139; 25°C: 169 and Ro at 20°C: 134; 25°C: 156). Whereas the alternative generation time (To, T1, T) and population doubling time (PDT) are faster at 25°C in both bacterial densities, the intrinsic rate of natural increase (rm) is faster at lower temperatures (20°C) in both bacterial densities. The average lifespan of C. brenneri is seven days when fed with A. faecalis. Offspring somatic growth (body length and width) was influenced by bacterial food density-temperature interaction with increased length and girth observed in higher bacterial density and temperature in our knowledge. This study is the first attempt to use A. faecalis, a wild-type bacterium from the terrestrial slug P. moellendorffi cadaver, as the bacterial food source for a Caenorhabditis LHT analysis.
Distribution of ESBL-producing and non-ESBL-producing Klebsiella pneumoniae isolated from sputum specimens in the Zainoel Abidin General Hospital, Banda Aceh, Indonesia
Authors: SUHARTONO SUHARTONO , HAYATI ZINATUL , MAHDANI WILDA , ANDINI FIRA
Published: October 2024

Abstract. Suhartono S, Hayati Z, Mahdani W, Andini F. 2024. Distribution of ESBL-Producing and Non-ESBL-Producing Klebsiella pneumoniae isolated from sputum specimens in the Zainoel Abidin General Hospital, Banda Aceh, Indonesia. Biodiversitas 25: 3247-3254. Klebsiella pneumoniae, a significant nosocomial pathogen, particularly in the case of strains producing extended-spectrum beta-lactamase (ESBL), was the focus of this study. The study aimed to determine the distributions stratified by patients’ age, sex, hospital wards, and the antimicrobial susceptibility pattern of ESBL and non-ESBL K. pneumoniae isolated from expectorate sputum at Zainoel Abidin General Hospital (RSUD dr. Zainoel Abidin), Banda Aceh, Indonesia, from January 2021 to January 2024. The prevalence of ESBL-producing K. pneumoniae was 79.84% (103/129 isolates), with the highest incidence found in patients aged >45 years (74.76%) and males (67.96%). The prevalence of non-ESBL-producing K. pneumoniae was 20.16% (26 isolates), with the highest incidence in patients aged >45 years (76.92%) and males (62.23%). The surgical ward had the highest incidence of ESBL-producing K. pneumoniae (14.56%), followed by the cardiopulmonary ward (14.56%). The cardiopulmonary ward also had the highest incidence of non-ESBL-producing K. pneumoniae (38.47%). The ESBL-producing K. pneumoniae isolates were more sensitive to amikacin than non-ESBL isolates, while the non-ESBL-producing K. pneumoniae isolates were sensitive to cefotaxime, amikacin, and tobramycin. The increasing prevalence of ESBL-producing K. pneumoniae underscores the significance of the study's findings, providing valuable insights into the epidemiology and antibiotic susceptibility profiles of K. pneumoniae in this clinical setting and the importance of reasonable antibiotic use.
Biochemical composition and volatile profile analysis of three varieties of Coffea arabica and their correlation with the microclimate of Mount Tangkuban Perahu, West Java, Indonesia
Authors: FIRNABILLAH ROSY ANNAZA , MUSTARI ERI , MARWANI ERLY
Published: October 2024

Abstract. Firnabillah RA, Mustari E, Marwani E. 2024. Biochemical composition and volatile profile analysis of three varieties of Coffea arabica and their correlation with the microclimate of Mount Tangkuban Perahu, West Java, Indonesia. Biodiversitas 25: 3264-3276. The quality of coffee is determined by various biochemical compounds, including chlorogenic acid, caffeine, trigonelline, sucrose, and oil, as well as the volatile metabolite profile in coffee beans. Genetic factors and environmental conditions at the coffee cultivation site influence the composition of these compounds. This study aimed to analyze the biochemical composition and volatile profile of various coffee samples, including Ateng, Tim-Tim, and Sigarar Utang, and investigate their correlation with microclimate factors. Different analytical methods were used to examine the green beans, including High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) for caffeine, chlorogenic acids, sucrose, and trigonelline, Soxhlet methods for oil content determination, and Gas Chromatography-Mass Spectrometry (GC-MS) for volatile compound analysis. The results showed distinct biochemical components and metabolite profiles among the three arabica coffee varieties. The Ateng variety had the highest concentrations of chlorogenic acid, while the Tim-Tim variety had the lowest content of these compounds. Trigonelline and caffeine content was similar across all varieties. Sucrose content was highest in the Sigarar Utang variety, while oil content was higher in the Ateng and Tim-Tim varieties compared to Sigarar Utang. Principal Component Analysis (PCA) showed significant metabolite variation among the three varieties, with PC1 and PC2 accounting for 69.2% of the variance. Furthermore, Partial Least Squares-Discriminant Analysis (PLS-DA) successfully distinguished the three varieties and identified potential biomarker compounds for classification. Additionally, the study discovered that the environmental factor, specifically light intensity affected the sucrose and oil compounds in arabica green beans coffee. The study concluded that the three varieties' biochemical composition and volatile metabolites differed. Certain compounds were found to correlate with measured microclimatic factor.
Scenario of stable transition from diffeomorphism of torus isotopic to identity one to skew product of rough transformations of circle
Authors: Baranov Denis A , Nozdrinova Elena Vyacheslavovna , Pochinka Olga Vital'evna
Published: October 2024

In this paper, we consider gradient-like diffeomorphisms of a two-dimensional torus isotopic to the identical one. The isotopicity of diffeomorphisms $f_0$, $f_1$ on an $n$-manifold $M^n$ means the existence of some arc $\{f_t:M^n\to M^n,t\in[0,1]\}$ connecting them in the space of diffeomorphisms. If isotopic diffeomorphisms are structurally stable (qualitatively not changing their properties with small perturbations), then it is natural to expect the existence of a stable arc (qualitatively not changing its properties under small perturbations) connecting them. In this case, one says that the isotopic diffeomorphisms $f_0$, $f_1$ are stably isotopic or belong to the same class of stable isotopic connectivity. The simplest structurally stable diffeomorphisms on surfaces are gradient-like transformations having a finite hyperbolic non-wandering set, stable and unstable manifolds of various saddle points of which do not intersect. However, even on a two-dimensional sphere, where all orientation-preserving diffeomorphisms are isotopic, gradient-like diffeomorphisms are generally not stably isotopic. The countable number of pairwise different classes of stable isotopic connectivity is constructed on the base of a rough transformation of the circle $\phi_{\frac{k}{m}}$ with exactly two periodic orbits of the period $m$ and the rotation number $\frac{k}{m}$, which can be continued to a diffeomorphism $F_{\frac k m}:\mathbb S^2\to\mathbb S^2$ with two fixed sources at the North and South poles. On the torus $\mathbb T^2$, the model representative in the considered class is the skew products of rough transformations of a circle. We show that any isotopic gradient-like diffeomorphism of a torus is connected by a stable arc with some model transformation.
Random walks on a line and algebraic curves
Authors: Grishin Stanislav Vladimirovich
Published: October 2024

This work is devoted to the studying the generating function of the first hitting time of the positive semi-axis under the homogeneous discrete integer random walk on a line. In the first part of the work the increments are supposed to be independent. Recurrent relations for the probabilities allow us to write the system of equations for the sought generating function. Applying the resultants technique, we succeed to reduce this system to a single equation. Then we can study it by calculating the genus of the correposponding plane algrebraic curve via analyzing its singularities. In the work we write the sought equations for some random walks and we show that if the increments take all integer values from $-2$ to $2$, or from $-1$ to $3$ with equal probabilities or they take equally probable values $-1$ and $4$, then the curve is rational, while this is not true in the first case. In the second part of the work we consider a symmetric process, the increments take the values $-1$, $0$, $1$, but then we suppose a non-zero correlation of each next increment with the previous one. For such process the equation for the generating function defines an elliptic curve depending on the square of the correlation coefficient for neighbouring increments if all increments are non-zero and it defines a hyperelliptic curve of genus $2$. The degeneration criterion of the latter is the presence of multiple roots of a sixth order polynomial under general symmetrically distributed conditional probabilities.
Influence of Winkler - Steklov conditions on natural oscillations of elastic weighty body
Authors: Nazarov Sergei Aleksandrovich
Published: October 2024

We consider the spectral problem for the spacial system of equations of the elasticity theory. Small parts of the body surface are supplied with the Winkler - Steklov conditions, which model spring mount, while the remaining part of the boundary is traction-free. In several cases (the relative stiffness of springs and their positions are varied) we construct asymptotics for eigenfrequencies of the body and for corresponding eigenmodes. The limiting problems are ones for the body (spectral or stationary in some case) and problems of the elasticity theory for the half-spaces with the Winkler - Steklov conditions on flat sets (separated or joined into a single spectral theory in some cases). The discreteness of the spectrum of the problem in the half-space is ensured by a polynomial property of the system of equations of the elasticity theory. We study particular cases, formulate open questions and discuss patological situations, in which the spectrum loses usual properties. We construct asymptotic models of the problem, which provide two-terms asymptotics for the eigenpairs of the initial problem and which use the technique of self-adjoint extensions of differential operators or Hilbers spaces with separated asymptotics.
Generalized composition operators on weighted Fock spaces
Authors: Worku Mafuz , Wesen Legessa Tekatel
Published: October 2024

The generalized composition operators $J_g^{\varPhi}$ and $C_g^{\varPhi}$, induced by analytic functions $g$ and $\varPhi$ on the complex plane $\mathbb{C}$, are defined by \begin{align*} J_g^{\varPhi}(f)(z)=\int\limits_0^zf'(\varPhi(\omega))g(\omega)d\omega and C_g^{\varPhi}(f)(z)=\int\limits_0^{\varPhi(z)}f'(\omega)g(\omega)d\omega. \end{align*} In this paper, we consider these operators on weighted Fock spaces $\mathcal{F}_p^{\varPsi}$, consisting of entire functions, which are $\mathcal{L}^p(\mathbb{C})$-integrable with respect to the measure $d\lambda(z)=e^{-\varPsi (z)}d\Lambda(z)$, where $d\Lambda$ is the usual Lebesgue area measure in $\mathbb{C}$. We assume that the weight function $\varPsi$ in the spaces satisfies certain smoothness conditions, in particular, this weight function grows faster than the Gaussian weight $\frac{|z|^2}{2}$ defining the classical Fock spaces. We first consider bounded and compact properties of $J_{g}^ {\varPhi}$ and $C_{g}^{\varPhi}$, and characterize these properties in terms function theory of inducing functions $g$ and $\varPhi$, given by \begin{align*} \mathcal{M}_g^{\varPhi}(z):=\frac{|g(z)|\varPsi'(\varPhi(z))}{1+\varPsi'(z)}e^{\varPsi(\varPhi(z))-\varPsi(z)}. \end{align*} Our characterization is simpler to use than the Berezin type integral transform characterization. In some cases, our result shows that these operators experience poorer boundedness and compactness structures when acting between such spaces than the classical Fock spaces. For instance, for $\varPhi(z)=z$, there is no nontrivial bounded $J_g^{\varPhi}$ and $C_g^{\varPhi}$ on weighted Fock spaces. In the case of classical Fock spaces, they are bounded if and only if $g$ is constant. In the second part of this paper, we apply our simpler characterization of boundedness and compactness to further study the Schatten-class membership of these operators. In particular, we express the Schatten $S_p(\mathcal{F}_2^{\varPsi})$ class membership property in terms of $\mathcal{L}^p(\mathbb{C}, \Delta \varPsi d\Lambda)$-integrability of $\mathcal{M}_g^{\varPhi}$.
Inductive methods for Hardy inequality on trees
Authors: Parfenov Anton Igorevich
Published: October 2024

We study the Hardy inequality on at most countable rooted tree. The main known criteria in the lower - triangle case for this inequality are two Arcozzi - Rochberg - Sawyer criteria and the capacity criterion. In the survey we show that these two criteria are connected with the criteria for the Hardy inequalities for the sequences, for the Hardy inequality on an interval of the real axis and for the trace inequalities with the Riesz potentials. We provide the examples from the literature, when the trace inequality or another statement is characterized in terms of the validity of the Hardy inequality on the tree. We simplify two known proofs of the Arcozzi - Rochberg - Sawyer criteria, which are based on the Marcinkiewicz interpolation theorem and on the capacity criterion. We provide new proofs for Arcozzi - Rochberg - Sawyer criteria, which are based on the induction in the tree, the inductive formula for the capacity and the formula of integration by parts. The latter of the proofs is written for the Hardy inequality on the tree with a boundary and for the Hardy inequality over the family of all binary cubes. In the diagonal case this proof provides an optimal constant $p$, which coincides with the Bennett constant in the Hardy inequality for the sequences. In the general case we provide a few new inductive criteria for the validity of the Hardy inequality in terms of the existence of a family of functions satisfying an inductive relation. One of these criteria is applied in the proof of a theorem containing additional equivalent conditions for the validity of the Hardy inequality on the trees in the diagonal case.
On mean - square approximation of functions in Bergman space $B_2$ and value of widths of some classes of functions
Authors: Shabozov Mirgand Shabozovich , Tukhliev Dilshod Kamaridinovich
Published: October 2024

Let $A(U)$ be a set of functions analytic in the circle $U:=z\in\mathbb{C}, |z|<1\}$ and $B_{2}:=B_{2}(U)$ be the space of the functions $f\in A(U)$ with a finite norm $$\|f\|_{2}=(\frac{1}{\pi}\iint_{(U)}|f(z)|^{2} d\sigma)^{\frac{1}{2}}<\infty,$$ where $d\sigma$ is the area differential and the integral is treated in the Lebesgue sense. In the work we study extremal problems related with the best polynomial approximation of the functions $f\in A(U)$. We obtain a series of sharp theorems and calculate the values of various $n$ - widths of some classes of functions defined by the continuity moduluses of $m$th order for the $r$th derivative $f^{(r)}$ in the space $B_2$.
Improved hole injection for AlGaN-based DUV LEDs with graded-composition multiple quantum barrier insertion layers
Authors: Tang Yizheng , Qi Ying , Lu Yunshu , Li Shuti , Liu Chao
Published: October 2024

The primary impediments to achieving high external quantum efficiency (EQE) and light output power (LOP) in AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) are inadequate hole injection efficiency and pronounced electron leakage. The significant polarization-induced positive charges, originating from the discontinuity in the Al composition between the last quantum barrier (LQB) and electron-blocking layer (EBL), attract electrons, consume holes, and reflect holes back into the p-type region, leading to severe electron leakage and low hole injection efficiency. In this paper, we introduce a graded-composition multiple quantum barrier (GQB) structure at the LQB/EBL interface. We adjust the Al composition in the insertion layer to alter the electrical polarity of the polarization-induced sheet charges, thereby modifying the electric field distribution in the EBL, LQB, and inserted GQB structure. Consequently, holes acquire boosted energy during their migration towards the active region. In addition, we enhance the hole injection and electron confinement ability via reducing the effective valence band barrier height and increasing the effective conduction band barrier height, thus diminishing the possibility of electron leakage from the active region into the p-type region. Therefore, the GQB structure proposed in this study provides a promising approach to improving the optical and electrical performance of DUV LEDs.
Integratable high-efficiency achromatic metalens across the entire low-loss bands of optical fiber from 1260 to 1625  nm
Authors: Cheng Dongping , Zou Xiujuan , Wan Peng , Chen Mengdan , Li Wenjie , Zhai Yalin , Jiang Mingming , Kan Caixia
Published: October 2024

A challenge in optic fiber is to control dispersion over the entire low-loss bands covering the O + E + S + C + L bands with integratable ultracompact devices, which inevitably limits the range of fiber-based applications. Metalens supplies a dynamic platform for correcting chromatic aberration of optical devices in a flexible, integratable, and ultracompact way. Hence, we propose a broadband achromatic metalens integrated on the end face of a single-mode fiber covering the entire low-loss wavelength region. Utilizing the particle swarm optimization algorithm, we have substantially mitigated the phase-compensated matching error in the achromatic scheme. It demonstrates that the metalens is achievable with achromatic aberration and focuses over the entire low-loss wavelength band with a high mean focusing efficiency of 84.55%. Furthermore, this device exhibits a remarkable capability to break through the diffraction limit of the output field. This work provides a theoretical basis for fiber-integrated achromatic metalens over the entire low-loss bands, which has promising applications in imaging, sensing, and optical communication.
Wavepacket interference of two photons through a beam splitter: from temporal entanglement to wavepacket shaping
Authors: Tian Zhaohua , Liu Qi , Tian Yu , Gu Ying
Published: October 2024

Quantum interferences based on beam splitting are widely used for entanglement. However, the quantitative measurement of the entanglement in terms of temporal modes and wavepacket shaping facilitated by this entanglement remain unexplored. Here we analytically study the interference of two photons with different temporal shapes through a beam splitter (BS) and then propose its application in temporal entanglement and shaping of photons. The temporal entanglement described by Von Neumann entropy is determined by the splitting ratio of BS and temporal indistinguishability of input photons. We found that maximum mode entanglement can be achieved with a 50/50 BS configuration, enabling the generation of a Bell state encoded in temporal modes, independent of the exact form of the input photons. Then, detecting one of the entangled photons at a specific time enables the probabilistic shaping of the other photon. This process can shape the exponentially decaying (ED) wavepacket into the ED sine shapes, which can be further shaped into Gaussian shapes with a fidelity exceeding 99%. The temporal entanglement and shaping of photons based on interference may solve the shape mismatch issues in large-scale optical quantum networks.
Wide-field scanning ghost imaging based on a local binary pattern and untrained neural network
Authors: Nan Suqin , Luo Lin , Zou Xuanpengfan , Guo Yang , Huang Xianwei , Tan Wei , Zhu Xiaohui , Jiang Teng , Li Chuang , Bai Yanfeng , Fu Xiquan
Published: October 2024

Continuous scene imaging is an important research goal in the field of autonomous driving, and the key is to ensure the imaging quality and efficiency. In this paper, we propose a method for information fusion in wide-field scanning ghost imaging using a local binary pattern (LBP) based on deep learning. The initial physical model formed by the LBP integrated into a deep neural network, which effectively enhances the expression of image texture details. Then the collected bucket signals are used as labels for adaptive image reconstruction, enabling the acquisition of images at each scanning position without the need for training on any dataset. Moreover, by employing weighted fusion to combine the image data from each scanning position, which effectively eliminates gaps that arise from direct stitching. Both simulation and experimental results demonstrate that our approach is capable of achieving high-quality detailed imaging with fewer measurements. Additionally, we analyze the impact of the projection beam step length, finding that our method yields significantly better imaging quality with larger steps compared to other methods using smaller steps. Our research also has the application prospect in medical detection, remote sensing and other fields.
Application of deep learning in active alignment leads to high-efficiency and accurate camera lens assembly
Authors: Liu Haibin , Li Wenyong , Gao Shaohua , Jiang Qi , Sun Lei , Zhang Benhao , Zhao Liefeng , Zhang Jiahuang , Wang Kaiwei
Published: October 2024

Active alignment plays a crucial role in minimizing decentering errors in optical systems and enhancing imaging quality. Traditional alignment techniques typically pay less attention to alignment speed and require precision apparatuses, such as laser locators, wavefront sensors and so on. To address these issues, this paper proposes a learning-search method that combines deep learning with search for achieving efficient alignment with a simple hardware system. With the powerful analytical capabilities of deep learning for images, our method achieves a speed of 9.2 seconds in experiments, which is a 56% improvement over the conventional search-based method. In terms of accuracy, it reaches an average weighted modulation transfer function (WMTF) of 0.594, with a difference from search-based method of no more than 0.003. Our method significantly improves alignment speed while maintaining accuracy, making it well-suited for large-scale applications.
Subwavelength-modulated silicon photonics for low-energy free-electron-photon interactions
Authors: Ates Omer Emre , Slayton Benjamin J. , Putnam William P.
Published: October 2024

We investigate silicon waveguides with subwavelength-scale modulation for applications in free-electron-photon interactions. The modulation enables velocity matching and efficient interactions between low-energy electrons and co-propagating photons. Specifically, we design a subwavelength-grating (SWG) waveguide for interactions between 23-keV free electrons and ≈1500-nm photons. The SWG waveguide and electron system exhibit a coupling coefficient of |gQu| = 0.23, and as we corroborate with time-domain, particle-in-cell simulations, the system operates as a backward-wave oscillator. Overall, our results show that modulated waveguides could open the door to strong, extended interactions between photons and low-energy (10-keV-scale) electrons, like those typically present in scanning electron microscopes. Additionally, our SWG waveguide design suggests that periodic waveguides could offer intriguing dispersion engineering opportunities for tailoring these interactions.
Fivefold increased power handling in waveguide UTC-PDs using dual-injection shared CPW PD-arrays
Authors: de Graaf J. P. , van Veldhoven R. , Williams K. A. , Jiao Y.
Published: October 2024

This work presents two circuit-based solutions to enhance the power handling capabilities of waveguide-integrated uni-travelling carrier photodetectors (WG-UTC-PDs). Compared to a baseline WG-UTC-PD, these solutions achieve a fivefold increase in photocurrent before thermal breakdown. First, dual-injection improves the optical power distribution within a baseline WG-UTC-PD, raising the photocurrent threshold before thermal breakdown. Second, an array of four optically parallel WG-UTC-PDs, electrically connected to a single coplanar waveguide (CPW) line, further increases the maximum photocurrent by distributing the input optical power across multiple PDs. The design omits a termination resistor, as the arrays do not rely on a traveling wave configuration, maximizing photocurrent without a 50% reduction of bandwidth. Both 4-PD single-injection and dual-injection arrays were designed, fabricated, and characterized. Compared to a baseline UTC-PD, with a maximum photocurrent of 1.8 mA at a 3 dB bandwidth of 55 GHz, the 4-PD single-injection circuit achieved 5.1 mA at 43 GHz. The dual-injection array further increased the photocurrent to 9.2 mA at a bandwidth of 35 GHz. Electrical reflection measurements confirmed the negative effects of CPW losses on RF performance. These power handling improvements enable compact, high-power integrated solutions for microwave photonics.
Optically transparent, broadband and omnidirectional microwave absorber based on graphene-SiO2 metasurfaces
Authors: Kwon Hoyeong , D’Aguanno Giuseppe , Alù Andrea
Published: October 2024

Broadband and omnidirectional absorption of electromagnetic waves is required in various technologies, such as stealth, high quality wireless communications, spacecraft shielding. In this study, we theoretically and numerically study a graphene-based absorber achieving broadband and omnidirectional absorption from 4 GHz to 100 GHz and 0∘ to 50∘∼70∘, with over 90% absorption efficiency. By applying a thin layer of graphene upon a SiO2 moth-eye structure, we show that electromagnetic waves can be effectively absorbed in the graphene layer and that the structure is optically transparent, ideal for civilian and military applications.
Compact speckle spectrometer using femtosecond laser-induced double-sided surface nanostructures
Authors: Xu Yunlong , Wu Jie , Li Hongru , Cai Rui , Zhu Yuehong , Li Yue , Shang Tao , Zhou Hao , Deng Guoliang
Published: October 2024

The utilization of light scattering in disordered media has shown
promise in the design of highly sensitive speckle spectrometers.
Significant advances have been made in the research of all-fiber
speckle spectrometers, and various planar scattering media have also
garnered the attention of many researchers. In this study, we designed
a compact speckle spectrometer employing a femtosecond laser to induce
double-sided nanostructures on a quartz glass as a scattering medium.
Once the transmission matrix is calibrated, the spectrum can be
reconstructed over a bandwidth of 100 nm, achieving a spectral
resolution of 0.1 nm. A 5 pm spectral resolution has
been demonstrated by integrating a neural network to recognize speckle
patterns in 100 pm bandwidths at 1500, 1550, and
1600 nm. By combining ResNet-50 and GRU, a simulated continuous
spectrum spinning a bandwidth of 2 nm can be accurately
reconstructed. This innovative, compact spectrometer features low
cost, small size, simple preparation, and repeatability.
Frequency shift caused by a magnetic field and light intensity inhomogeneity in an optically detected clock
Authors: Li Yuanhao , Liu Chen , Chen Sifei , Fan Lifeng , Lyu Hangzhe , Feng Chen , Duan Jian , Wang Yanhui
Published: October 2024

We present a novel, to the best of our knowledge, frequency shift mechanism in the optically detected atomic clock. This frequency shift is analogous to the light shift that is associated with a detecting light power. However, this shift arises from the inhomogeneity of the magnetic field (C-field) and the detecting light intensity. We call this shift the “pseudo-light shift” (p-LS). This shift allows the correlation between the clock output frequency and the detecting light power to switch between positive and negative, depending on the magnetic field. The mechanism is described and experimentally validated in our cesium beam clock through two experiments. The study of this frequency shift can enhance the accuracy of light shift assessments in atom–laser interaction systems and suppress long-term stability deterioration caused by the light power fluctuation.
Poincaré tornados
Authors: Brimis Apostolos , Makris Konstantinos G. , Papazoglou Dimitris G.
Published: October 2024

We show that Poincaré polarization singularities, spiraling like a tornado, can be generated by superimposing two orthogonally polarized, abruptly auto-focusing ring-Airy beams that carry orbital angular momentum (OAM). Seeded by phase vortices of the same helicity, which are adapted to the high-intensity rings of one of the superimposing beams, these polarization singularities follow trajectories that twist and shrink in an accelerating fashion along their propagation. Reaching angular acceleration that exceeds 120 rad/mm2, these Poincaré tornados can find application in singular optics, wavefront shaping, polarization engineering, and imaging through complex media.
Intense white-light emission of amorphous lead chloride trimers at high pressure
Authors: Meng Xinmiao , Wang Yayun , Wang Yanan , Li Aisen , Fang Yuanyuan , Li Lei , Wang Kai , Li Qian
Published: October 2024

Developing efficient, single-phase white-light phosphors remains a formidable challenge in optoelectronics. Herein, high pressure initially induces trimeric contraction and distortion in (C9NH20)9(ZnCl4)2[Pb3Cl11], regulating the transition equilibrium of self-trapped excitons (STEs) with varied emission colors. Then, considerable structural distortion and destruction lead to intense white-light emission of an amorphous phase. A narrowed bandgap with promoted excitation efficiency, as well as strengthened electron–phonon coupling effect with increased binding energy of STEs, together result in the significant emission enhancement. This work provides valuable insights into white-light luminescent materials and offers new strategies for designing white-light-emitting devices.
Effect of the estimation result of the degree of polarization of target light on clear imaging
Authors: Deng Jinxin , Zhu Jingping , Li Haoxiang , Li Angze , Kuang Yucai , Liu Xiaofang , Hou Xun
Published: October 2024

Previous underwater imaging methods have not developed a clear idea of estimating the degree of polarization of target light (Pobj). To address this issue, this Letter answers the question of how the estimation result of Pobj affects clear imaging. First, the theoretical derivation states that Pobj is simply a scale modulation factor of the imaging result. Second, experiments are conducted for validation, and results conform well to the derivation. Hence, the effect of the estimated Pobj on clear imaging is obtained. This parameter only influences brightness rather than contrast but may cause noise amplification as well as the unfavorable result of negative pixels. Therefore, no precise estimation is needed; pick the value near the ends of the definition domain directly and take the absolute value. Based on these, a new imaging formula is proposed, enabling the processing time to fulfill the actual dynamic imaging requirements. As far as we are concerned, the attained prior knowledge and formula could provide strong assistance for underwater polarization imaging.
Abrupt and spontaneous strategy switches emerge in simple regularised neural networks
Authors: Löwe Anika T. , Touzo Léo , Muhle-Karbe Paul S. , Saxe Andrew M. , Summerfield Christopher , Schuck Nicolas W.
Published: October 2024

Humans sometimes have an insight that leads to a sudden and drastic performance improvement on the task they are working on. Sudden strategy adaptations are often linked to insights, considered to be a unique aspect of human cognition tied to complex processes such as creativity or meta-cognitive reasoning. Here, we take a learning perspective and ask whether insight-like behaviour can occur in simple artificial neural networks, even when the models only learn to form input-output associations through gradual gradient descent. We compared learning dynamics in humans and regularised neural networks in a perceptual decision task that included a hidden regularity to solve the task more efficiently. Our results show that only some humans discover this regularity, and that behaviour is marked by a sudden and abrupt strategy switch that reflects an aha-moment. Notably, we find that simple neural networks with a gradual learning rule and a constant learning rate closely mimicked behavioural characteristics of human insight-like switches, exhibiting delay of insight, suddenness and selective occurrence in only some networks. Analyses of network architectures and learning dynamics revealed that insight-like behaviour crucially depended on a regularised gating mechanism and noise added to gradient updates, which allowed the networks to accumulate “silent knowledge” that is initially suppressed by regularised gating. This suggests that insight-like behaviour can arise from gradual learning in simple neural networks, where it reflects the combined influences of noise, gating and regularisation. These results have potential implications for more complex systems, such as the brain, and guide the way for future insight research.
Measuring the climate security nexus: The Integrated Climate Security Framework
Authors: Pacillo Grazia , Medina Leonardo , Liebig Theresa , Carneiro Bia , Schapendonk Frans , Craparo Alessandro , Ramirez-Villegas Julian , Basel Ashleigh , Minoarivelo Henintsoa Onivola , Estrella Harold Achicanoy , Villa Victor , Belli Anna , Caroli Giulia , Madurga-Lopez Ignacio , Scartozzi Cesare , DuttaGupta Tanaya , Mendez Andres , Kenduiywo Benson , Resce Giuliano , Ruscica Giosue , Sax Niklas , Mastrorillo Marina , Läderach Peter
Published: October 2024

International, regional, and national organizations, alongside policymakers, are increasingly acknowledging the crucial connection between climate, peace, and security. However, there remains a notable gap in research methodologies capable of fully grasping the intricate dynamics of this relationship. This paper introduces the Integrated Climate Security Framework (ICSF), a comprehensive mixed-methods approach designed to unravel the complexities of climate-human security-conflict connections across various scales. By integrating traditional and innovative research methods, the ICSF aims to provide cutting-edge, policy-relevant insights to address five main measurement challenges of the climate security nexus: multiple pathways; context specificity; non-linearity; multiple actors and scales, and multiple geographic and time scales. By drawing on diverse epistemological perspectives and engaging directly with local communities, the framework offers a comprehensive evaluation of the complex social-ecological dynamics at play. Using Kenya as a case study—a country where climate and security risks frequently intersect and amplify each other—we demonstrate the comprehensive insights the framework offers to address the complex challenges at the nexus of climate, human security, and conflict.
The Drosophila circadian clock gene cycle controls the development of clock neurons
Authors: Biondi Grace , McCormick Gina , Fernandez Maria P.
Published: October 2024

Daily behavioral and physiological rhythms are controlled by the brain’s circadian timekeeping system, a synchronized network of neurons that maintains endogenous molecular oscillations. These oscillations are based on transcriptional feedback loops of clock genes, which in Drosophila include the transcriptional activators Clock (Clk) and cycle (cyc). While the mechanisms underlying this molecular clock are very well characterized, the roles that the core clock genes play in neuronal physiology and development are much less understood. The Drosophila timekeeping center is composed of ~150 clock neurons, among which the four small ventral lateral neurons (sLNvs) are the most dominant pacemakers under constant conditions. Here, we show that downregulating the clock gene cyc specifically in the Pdf-expressing neurons leads to decreased fasciculation both in larval and adult brains. This effect is due to a developmental role of cyc, as both knocking down cyc or expressing a dominant negative form of cyc exclusively during development lead to defasciculation phenotypes in adult clock neurons. Clk downregulation also leads to developmental effects on sLNv morphology. Our results reveal a non-circadian role for cyc, shedding light on the additional functions of circadian clock genes in the development of the nervous system.
HTL/KAI2 signaling substitutes for light to control plant germination
Authors: Hountalas Jenna E. , Bunsick Michael , Xu Zhenhua , Taylor Andrea A. , Pescetto Gianni , Ly George , Boyer François-Didier , McErlean Christopher S. P. , Lumba Shelley
Published: October 2024

Plants monitor multiple environmental cues, such as light and temperature, to ensure they germinate at the right time and place. Some specialist plants, like ephemeral fire-following weeds and root parasitic plants, germinate primarily in response to small molecules found in specific environments. Although these species come from distinct clades, they use the same HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE 2 (HTL/KAI2) signaling pathway, to perceive different small molecules suggesting convergent evolution on this pathway. Here, we show that HTL/KAI2 signaling in Arabidopsis thaliana bypasses the light requirement for germination. The HTL/KAI2 downstream component, SUPPRESSOR OF MAX2 1 (SMAX1) accumulates in the dark and is necessary for PHYTOCHROME INTERACTING FACTOR 1/PHYTOCHROME INTERACTING FACTOR 3-LIKE 5 (PIF1/PIL5) to regulate hormone response pathways conducive to germination. The interaction of HTL/KAI2 and light signaling may help to explain how specialist plants like ephemeral and parasitic weeds evolved their germination behaviour in response to specific environments.
The role and value of counsellors in the treatment journeys of people with tuberculosis and their families: Qualitative insights from the South Fly District of Papua New Guinea
Authors: Jops Paula , Cowan John , Trumb Richard Nake , Kupul Martha , Kuma Allan , Bell Stephen , Keam Tess , Bauri Mathias , Nindil Herolyn , Majumdar Suman S. , Finch Stacia , Pomat William , Marais Ben J. , Marks Guy B. , Kaldor John , Vallely Andrew , Graham Stephen M. , Kelly-Hanku Angela
Published: October 2024

Combined education and counselling can contribute to person-centred care for tuberculosis (TB), improving uptake, adherence, and outcomes of treatment for TB disease and TB infection. Though strongly recommended by the World Health Organization for all people diagnosed with TB, education and counselling is not widely implemented in TB programs around the world. In 2016, a pilot TB education and counselling program, delivered by trained professionals and peers, was initiated to support people on TB treatment in the South Fly District of Papua New Guinea. This article reports on select findings from a qualitative study that examined the socio-cultural dimensions of TB, including treatment support such as education and counselling, in the South Fly District. An assessment on data collected during 128 semi-structured in-depth interviews of the role of counsellors on TB treatment journeys revealed strong participant support for the counsellors and the services they delivered, with particular emphasis on the emotional support provided to address fears and concerns related to TB diagnosis and treatment, and to support treatment adherence; valuable attributes of counsellors; their role as intermediaries between patients and health workers; their provision of biomedical knowledge of TB transmission and disease; and their assistance in addressing stigma and discrimination from family and community. Participants also noted how tackling the socio-structural issues that drive TB transmission in people’s homes and communities were beyond the remit of counsellors’ work. TB education and counselling should be an essential part of all TB services to provide support and encouragement for people to continue treatment to completion.
Explaining socioeconomic inequality in food consumption patterns among households with women of childbearing age in South Africa
Authors: Nglazi Mweete D. , Ataguba John E.
Published: October 2024

The changing food environment shifts peoples’ eating behaviour toward unhealthy food, including ultra-processed food (UPF), leading to detrimental health outcomes like obesity. This study examines changes in socioeconomic inequalities in food consumption spending between 2005/06 and 2010/11 in South African households with women of childbearing age (15 to 49) (WCBA). Data come from the 2005/06 and 2010/11 Income and Expenditure Surveys. The distribution of spending according to the NOVA food classification system groupings (unprocessed or minimally processed foods, processed culinary ingredients, processed and UPF products) was analysed using standard methodologies. Changes in spending inequalities between 2005/06 and 2010/11 were assessed using the concentration index (C), while the factors explaining the changes in spending inequalities were identified using the Oaxaca decomposition approach. The Kakwani index (K) was used to assess progressivity. Results show that average real spending on all food categories, including UPF, increased between 2005/06 and 2010/11. Socioeconomic inequality in UPF consumption spending decreased (C = 0.498 in 2005/06 and C = 0.432 in 2010/11), and spending on processed foods (C = 0.248 in 2005/06 and C = 0.209 in 2010/11). Socioeconomic status, race, and urban residence contributed to overall socioeconomic inequality and changes in UPF consumption inequality between 2005/06 and 2010/11. Spending on all food categories was regressive in 2005/06 (K = -0.173 for UPF and -0.425 for processed foods) and 2010/11 (K = -0.192 for UPF and -0.418 for processed foods) because such spending comprises a larger share of poorer household’s income than their wealthier counterparts. The government should address these contributors to inequality to mitigate the risks associated with UPF consumption, especially among less affluent households.
3D CNN for neuropsychiatry: Predicting Autism with interpretable Deep Learning applied to minimally preprocessed structural MRI data
Authors: Garcia Mélanie , Kelly Clare
Published: October 2024

Predictive modeling approaches are enabling progress toward robust and reproducible brain-based markers of neuropsychiatric conditions by leveraging the power of multivariate analyses of large datasets. While deep learning (DL) offers another promising avenue to further advance progress, there are challenges related to implementation in 3D (best for MRI) and interpretability. Here, we address these challenges and describe an interpretable predictive pipeline for inferring Autism diagnosis using 3D DL applied to minimally processed structural MRI scans. We trained 3D DL models to predict Autism diagnosis using the openly available ABIDE I and II datasets (n = 1329, split into training, validation, and test sets). Importantly, we did not perform transformation to template space, to reduce bias and maximize sensitivity to structural alterations associated with Autism. Our models attained predictive accuracies equivalent to those of previous machine learning (ML) studies, while side-stepping the time- and resource-demanding requirement to first normalize data to a template. Our interpretation step, which identified brain regions that contributed most to accurate inference, revealed regional Autism-related alterations that were highly consistent with the literature, encompassing a left-lateralized network of regions supporting language processing. We have openly shared our code and models to enable further progress towards remaining challenges, such as the clinical heterogeneity of Autism and site effects, and to enable the extension of our method to other neuropsychiatric conditions.