bluuebunny/crossref_metadata_2025 huggingface dataset:
Rank the spreading influence of nodes using dynamic Markov process
Authors: Lin Jianhong , Chen Bo-Lun , Yang Zhao , Liu Jian-Guo , Tessone Claudio J.
Published: February 2023

Ranking the spreading influence of nodes is of great importance in practice and research. The key to ranking a node’s spreading ability is to evaluate the fraction of susceptible nodes being infected by the target node during the outbreak, i.e. the outbreak size. In this paper, we present a dynamic Markov process (DMP) method by integrating the Markov chain and the spreading process to evaluate the outbreak size of the initial spreader. Following the idea of the Markov process, this method solves the problem of nonlinear coupling by adjusting the state transition matrix and evaluating the probability of the susceptible node being infected by its infected neighbors. We have employed the susceptible-infected-recovered and susceptible-infected-susceptible models to test this method on real-world static and temporal networks. Our results indicate that the DMP method could evaluate the nodes’ outbreak sizes more accurately than previous methods for both single and multi-spreaders. Besides, it can also be employed to rank the influence of nodes accurately during the spreading process.
Random walk and non-Gaussianity of the 3D second-quantized Schrödinger–Newton nonlocal soliton
Authors: Conti Claudio
Published: February 2023

Nonlocal quantum fluids emerge as dark-matter models and tools for quantum simulations and technologies. However, strongly nonlinear regimes, like those involving multi-dimensional self-localized solitary waves, are marginally explored for what concerns quantum features. We study the dynamics of 3D+1 solitons in the second-quantized nonlocal nonlinear Schrödinger–Newton equation. We theoretically investigate the quantum diffusion of the soliton center of mass and other parameters, varying the interaction length. 3D+1 simulations of the Ito partial differential equations arising from the positive P-representation of the density matrix validate the theoretical analysis. The numerical results unveil the onset of non-Gaussian statistics of the soliton, which may signal quantum-gravitational effects and be a resource for quantum computing. The non-Gaussianity arises from the interplay between the soliton parameter quantum diffusion and the stable invariant propagation. The fluctuations and the non-Gaussianity are universal effects expected for any nonlocality and dimensionality.
On monogamy and polygamy relations of multipartite systems
Authors: Zhang Xia , Jing Naihuan , Liu Ming , Ma Haitao
Published: February 2023

We study the monogamy and polygamy relations related to quantum correlations for multipartite quantum systems in a unified manner. It is known that any bipartite measure obeys monogamy and polygamy relations for the r-power of the measure. We show in a uniformed manner that the generalized monogamy and polygamy relations are transitive to other powers of the measure in weighted forms We demonstrate that our weighted monogamy and polygamy relations are stronger than recently available relations. Comparisons are given in detailed examples which show that our results are stronger in both situations.
Silicon-on-silica waveguides-based all-optical logic gates at 1.55 μm
Authors: Kotb Amer , Zoiros Kyriakos E , Li Wei
Published: February 2023

The demand for faster and more efficient integrated photonic circuits has prompted the rise of silicon-on-insulator technology. In this paper, silicon-on-silica waveguides have been employed for the all-optical realization of a complete family of logic gates, including XOR, AND, OR, NOT, NOR, NAND and XNOR operated at 1.55 μm. This waveguide consists of three identical slots and six microring resonators, all made of silicon patterned on silica. The principle of operation of these logic gates is based on the constructive and destructive interference induced by the phase difference between the input signals. The gates’ performance is evaluated against the contrast ratio (CR) metric. Compared to existing waveguides, the proposed waveguides achieve higher CRs with a speed as high as 120 Gb s−1.
Free streaming length of axion-like particle after oscillon/I-ball decays
Authors: Imagawa Kaname , Kawasaki Masahiro , Murai Kai , Nakatsuka Hiromasa , Sonomoto Eisuke
Published: February 2023

Axion-like particles (ALPs) are pseudoscalar bosons predicted by string theory.
The ALPs have a shallower potential than a quadratic one, which induces the instability and can form the solitonic object called oscillon/I-ball.
Although the lifetime of oscillons can be very long for some type of potentials, they finally decay until the present.
We perform the numerical lattice simulations to investigate the decay process of oscillons and evaluate the averaged momentum of ALPs emitted from the oscillon decay.
It is found that, if oscillons decay in the early universe, the free-streaming length of ALPs becomes too long to explain the small-scale observations of the matter power spectrum.
We show that oscillons with long lifetimes can change the density fluctuations on small scales, which leads to stringent constraints on the ALP mass and the oscillon lifetime.
Upper limits on the polarized isotropic stochastic gravitational-wave background from advanced LIGO-Virgo's first three observing runs
Authors: Jiang Yang , Huang Qing-Guo
Published: February 2023

Parity violation is expected to generate an asymmetry between the amplitude of left and
right-handed gravitational-wave modes which leads to a circularly polarized stochastic
gravitational-wave background (SGWB). Due to the three independent baselines in the LIGO-Virgo
network, we focus on the amplitude difference in strain power characterized by Stokes' parameters
and do maximum-likelihood estimation to constrain the polarization degree of SGWB. Our results
indicate that there is no evidence for the circularly polarized SGWB in the data. Furthermore, by
modeling the SGWB as a power-law spectrum, we place upper limit on the normalized energy density
Ωgw(25 Hz) < 5.3 × 10-9 at 95% confidence level after marginalizing
over the polarization degree and spectral index.
Decoherence-free subspace and entanglement sudden death of multi-photon polarization states in fiber channels
Authors: Liu Yiwen
Published: February 2023

The construction of quantum networks requires long-distance teleportation of multi-qubit entangled states. Here, we investigate the entanglement dynamics of GHZ and W states in fiber channels. In a fiber channel, the two most important phenomena that affect polarization entanglement are polarization mode dispersion (PMD) and polarization-dependent loss (PDL). We theoretically characterize how PMD and PDL vectors affect three-qubit states. In particular, upon quantifying the entanglement at the output states using concurrence and entanglement witnesses, we reveal the occurrence of entanglement sudden death and the appearance of decoherence-free subspaces in tripartite systems. Finally, we explore the evolution of GHZ and W state with an arbitrary number of photons in a fiber network and discuss the decoherence mechanism of the 4-party cluster state.
A spin-based magnetic scanning microscope for in-situ strain tuning of soft matter
Authors: Ding Zhe , Sun Yumeng , Wang Mengqi , Yu Pei , Zheng Ningchong , Zang Yipeng , Wang Pengfei , Wang Ya , Nie Yuefeng , Shi Fazhan , Du Jiangfeng
Published: February 2023

We present a magnetic scanning microscope equipped with a nitrogen-vacancy (NV) center scanning probe that has the ability to mechanically tune the strain of soft matter in-situ. The construction of the microscope and a continuous strain-tuning sample holder are discussed. An optically detected magnetic resonance protocol utilized in the imaging is described. In order to show the reliability of this microscope, the strain conduction is estimated with finite element simulation, and x-ray diffraction is required for calibration when freestanding crystal films are under consideration. A magnetic imaging result is displayed to demonstrate the nano-scale imaging capability. The microscope presented in this work is helpful in studying strain-coupled magnetic physics such as magnetic phase transition under strain and strain-tuned cycloidal orientation tilting.
A thermal conductivity switch via the reversible 2H-1T′ phase transition in monolayer MoTe2
Authors: Zhang Dingbo , Ren Weijun , Wang Ke , Chen Shuai , Zhang Lifa , Ni Yuxiang , Zhang Gang
Published: February 2023

The two-dimensional (2D) material-based thermal switch is attracting attention due to its novel applications, such as energy conversion and thermal management, in nanoscale devices. In this paper, we observed that the reversible 2H–1T′ phase transition in MoTe2 is associated with about a fourfold/tenfold change in thermal conductivity along the X/Y direction by using first-principles calculations. This phenomenon can be profoundly understood by comparing the Mo–Te bonding strength between the two phases. The 2H-MoTe2 has one stronger bonding type, while 1T′-MoTe2 has three weaker types of bonds, suggesting bonding inhomogeneity in 1T′-MoTe2. Meanwhile, the bonding inhomogeneity can induce more scattering of vibration modes. The weaker bonding indicates a softer structure, resulting in lower phonon group velocity, a shorter phonon relaxation lifetime and larger Grüneisen constants. The impact caused by the 2H to 1T′ phase transition in MoTe2 hinders the propagation of phonons, thereby reducing thermal conductivity. Our study describes the possibility for the provision of the MoTe2-based controllable and reversible thermal switch device.
Localization of deep brain stimulation trajectories via automatic mapping of microelectrode recordings to MRI
Authors: Rao Akshay T , Chou Kelvin L , Patil Parag G
Published: February 2023

Objective. Suboptimal electrode placement during subthalamic nucleus deep brain stimulation (STN DBS) surgery may arise from several sources, including frame-based targeting errors and intraoperative brain shift. We present a computer algorithm that can accurately localize intraoperative microelectrode recording (MER) tracks on preoperative magnetic resonance imaging (MRI) in real-time, thereby predicting deviation between the surgical plan and the MER trajectories. Approach. Random forest (RF) modeling was used to derive a statistical relationship between electrophysiological features on intraoperative MER and voxel intensity on preoperative T2-weighted MR imaging. This model was integrated into a larger algorithm that can automatically localize intraoperative MER recording tracks on preoperative MRI in real-time. To verify accuracy, targeting error of both the planned intraoperative trajectory (‘planned’) and the algorithm-derived trajectory (‘calculated’) was estimated by measuring deviation from the final DBS lead location on postoperative high-resolution computed tomography (‘actual’). Main results. MR imaging and MERs were obtained from 24 STN DBS implant trajectories. The cross-validated RF model could accurately distinguish between gray and white matter regions along MER trajectories (AUC 0.84). When applying this model within the localization algorithm, the calculated MER trajectory estimate was found to be significantly closer to the actual DBS lead when compared to the planned trajectory recorded during surgery (1.04 mm vs 1.52 mm deviation, p < 0.002), with improvement shown in 19/24 cases (79%). When applying the algorithm to simulated DBS trajectory plans with randomized targeting error, up to 4 mm of error could be resolved to <2 mm on average (p < 0.0001). Significance. This work presents an automated system for intraoperative localization of electrodes during STN DBS surgery. This neuroengineering solution may enhance the accuracy of electrode position estimation, particularly in cases where high-resolution intraoperative imaging is not available.
Filter bank sinc-convolutional network with channel self-attention for high performance motor imagery decoding
Authors: Chen Jiaming , Wang Dan , Yi Weibo , Xu Meng , Tan Xiyue
Published: February 2023

Objective. Motor Imagery Brain-Computer Interface (MI-BCI) is an active Brain-Computer Interface (BCI) paradigm focusing on the identification of motor intention, which is one of the most important non-invasive BCI paradigms. In MI-BCI studies, deep learning-based methods (especially lightweight networks) have attracted more attention in recent years, but the decoding performance still needs further improving. Approach. To solve this problem, we designed a filter bank structure with sinc-convolutional layers for spatio-temporal feature extraction of MI-electroencephalography in four motor rhythms. The Channel Self-Attention method was introduced for feature selection based on both global and local information, so as to build a model called Filter Bank Sinc-convolutional Network with Channel Self-Attention for high performance MI-decoding. Also, we proposed a data augmentation method based on multivariate empirical mode decomposition to improve the generalization capability of the model. Main results. We performed an intra-subject evaluation experiment on unseen data of three open MI datasets. The proposed method achieved mean accuracy of 78.20% (4-class scenario) on BCI Competition IV IIa, 87.34% (2-class scenario) on BCI Competition IV IIb, and 72.03% (2-class scenario) on Open Brain Machine Interface (OpenBMI) dataset, which are significantly higher than those of compared deep learning-based methods by at least 3.05% (

p

= 0.0469), 3.18% (

p

= 0.0371), and 2.27% (

p

= 0.0024) respectively. Significance. This work provides a new option for deep learning-based MI decoding, which can be employed for building BCI systems for motor rehabilitation.
Connections between spatially distant primary language regions strengthen with age during infancy, as revealed by resting-state fNIRS
Authors: Paranawithana Ishara , Mao Darren , McKay Colette M , Wong Yan T
Published: February 2023

Objective. Hearing is an important sensory function that plays a key role in how children learn to speak and develop language skills. Although previous neuroimaging studies have established that much of brain network maturation happens in early childhood, our understanding of the developmental trajectory of language areas is still very limited. We hypothesized that typical development trajectory of language areas in early childhood could be established by analyzing the changes of functional connectivity in normal hearing infants at different ages using functional near-infrared spectroscopy. Approach. Resting-state data were recorded from two bilateral temporal and prefrontal regions associated with language processing by measuring the relative changes of oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) concentrations. Connectivity was calculated using magnitude-squared coherence of channel pairs located in (a) inter-hemispheric homologous and (b) intra-hemispheric brain regions to assess connectivity between homologous regions across hemispheres and two regions of interest in the same hemisphere, respectively. Main results. A linear regression model fitted to the age vs coherence of inter-hemispheric homologous test group revealed a significant coefficient of determination for both HbO (R
2 = 0.216, p = 0.0169) and HbR (R
2 = 0.206, p = 0.0198). A significant coefficient of determination was also found for intra-hemispheric test group for HbO (R
2 = 0.237, p = 0.0117) but not for HbR (R
2 = 0.111, p = 0.0956). Significance. The findings from HbO data suggest that both inter-hemispheric homologous and intra-hemispheric connectivity between primary language regions significantly strengthen with age in the first year of life. Mapping out the developmental trajectory of primary language areas of normal hearing infants as measured by functional connectivity could potentially allow us to better understand the altered connectivity and its effects on language delays in infants with hearing impairments.
Effect of driving pressure and flux rate on red wine nanofiltration
Authors: Lazarova M , Dencheva-Zarkova M , Yankov D , Genova J
Published: February 2023

Red wine contains many bioactive components, such as phenolics, which play a beneficial role on human health and also are responsible for important sensory qualities of wine. Membrane technology offers advantages compared to the conventional methods used for polyphenols extraction in terms of high recovery/removal efficiency, no phase transition and mild operating conditions. In this study, nanofiltration of the native Bulgarian red wine Mavrud was performed. The MaxiMem membrane filtration system employing the nanofiltration membrane Microdyn Nadir™ NP030 P (MWCO 500 Da) was used for this purpose. The effects of the operating parameters (transmembrane pressure and flow rate) on the retention of bioactive compounds in wine were investigated. The phenolic amount of the obtained wine after nanofiltration was evaluated and compared with the data of the original wine. It was found out that the examined nanofiltration membrane can be effectively used for concentration of phenolics in wine. Optimal results with 29 % concentration of the phenolics in the obtained wine were achieved applying two sets of pressure and flow rate, namely 40 bar and 1.2 L/min, and 30 bar and 3 L/min.
Enzyme activity of β-galactosidase immobilized in polyelectrolyte multilayers deposited on corona charged composite substrates
Authors: Grigorov A , Viraneva A , Marudova M , Yovcheva T , Iliev I
Published: February 2023

In the present paper chitosan and xanthan polyelectrolyte multilayers (PEMs) deposited on composite multicomponent poly(D-lactic acid) (PDLA) / poly(ε-caprolactone) (PEC) substrates were investigated. The substrates' melting phenomena and degree of crystallinity were investigated by differential scanning calorimetry (DSC). Based on the melting behaviour it was suggested that PLA and PEC are not miscible at molecular level and no co-crystallization is realized. The substrates obtained were charged in a corona discharge. Positive or negative 5 kV voltages were applied to the corona electrode and 1 kV voltage of the same polarity - to the grid. The normalized surface potential dependences on the storage times were investigated. The results obtained show that the values of the normalized surface potential decay faster for negatively charged substrates. Layer-by-layer (LbL) technique was used for multilayer deposition on the substrates. PEMs with 8 layers were obtained. The enzyme of β-galactosidase was immobilized in the obtained polyelectrolyte multilayers. The enzyme activity of the immobilized enzyme was studied. The experimental results obtained show that the enzyme immobilization in positively charged films have higher activity compared to the negatively charged ones, independently of substrates type.
Effect of nanofiller concentration on its dispersion in a system of liquid crystalline SB(3R)-11 and single walled carbon nanotubes
Authors: Exner Ginka , Marinov Yordan , Veerabhadraswamy Bhyranalyar , Yelamaggad Channabasaveshwar , Rafailov Peter , Georgieva Veselina
Published: February 2023

We report on the concentration dependence of the dispersion of single walled carbon nanotubes, SWCNTs, in a nanocomposite with a recently synthesized ferroelectric and optically active thermotropic liquid crystal ((R,E)-4-(4-((3,7-dimethyloctyl) oxy) styryl) phenyl 4-(undecyloxy)benzoate. Excellent dispersion of the SWCNTs in the concentration range from 0.01 up to 10 wt % was proven by means of differential scanning calorimetry, polarized optical microscopy, and Raman spectroscopy. It is believed to be facilitated by the formation of core-shell fibres, consisting of liquid crystal decorated SWCNTs, yet in the solution state. The fibres are maintained after the solvent evaporation and so the aggregation at elevated temperatures is prevented. The preservation of the liquid crystalline behaviour in all investigated cases can be considered as an additional benefit.
Crosslinked chitosan-based particles obtained by water-in-oil emulsion technique
Authors: Milenkova Sofia , Marudova Maria , Zahariev Nikolay , Yovcheva Temenuzhka , Pilicheva Bissera
Published: February 2023

Particles based on emulsified chitosan in oil phase have been reported in the present study. Sodium Tripolyphosphate (NaTPP) was introduced to them as a crosslinker and its effect on their properties was examined. Laser diffraction technique showed that the obtained structures are micronsized particles with single modal distribution. Optical microscopy has confirmed their size range, together with the fact that their shape is regular and spherical. Swelling studies in simulated saliva conditions (pH = 6.8) has shown a relation between the crosslinking degree of the particles and cycles of swelling and dissolution at different rates. Mucoadhesion test confirmed their potential as delivery systems through a mucosal route and showed dependence of the mucoadhesion properties upon the free amino groups left onto the chitosan chains.
Chitosan/grapeseed oil multicomponent edible films - design and properties
Authors: Gechev Biser , Zsivanovits Gabor , Iliev Angel , Marudova Maria
Published: February 2023

Physical and antioxidant properties of edible chitosan films, formed by casting method, were investigated. The films were loaded with grapeseed oil (GsO), which is a strong antioxidant, contains vitamin E and protects human cells against cancer. The mechanical puncture characteristics, thickness, water uptake, barrier, and antioxidant (DPPH assay) properties of the films were investigated. The results showed that the addition of GsO to chitosan film accelerated the oxygen and water vapor exchange and reduced the strength of the films. The increased antioxidant activity of the films is a prerequisite for extending the shelf life of food products packaged in them.
Polarised line shape calculations for conditions encountered in stellar magnetic atmospheres
Authors: Giustolisi L , Leone F , Stift M , Giarrusso M , Rosato J
Published: February 2023

We present new investigations into spectral line shapes under conditions typical for magnetic stellar atmospheres. Our method for simulating line profiles takes into account the coupled Zeeman and Stark effects. The calculations presented here will ultimately help to correctly model the Stokes parameters of peculiar stellar objects such as the Magnetic White Dwarfs (MWDs), retrieving their magnetic field geometries from spectropolarimetric observations. For the magnetic analysis of this class of stars, in general only Stokes I profiles as a function of rotational phase have been used in the past, in a very few cases, also Stokes V. The present improved simulations of the full Stokes parameters are expected to provide a powerful tool for the analysis of strong magnetic fields like those found in the MWDs.
Review of recent advances in the analytical theory of Stark broadening of spectral lines in plasmas: applications to laboratory discharges and astrophysical plasmas
Authors: Oks E. , Dalimier E. , Angelo P. , Sanders P.
Published: February 2023

We present an overview of latest advances in the analytical theory of Stark broadening of spectral lines and their applications to various types of laboratory and astrophysical plasmas. They include: 1) in-depth study of intra-Stark spectroscopy in the x-ray range in relativistic laser-plasma interactions; 2) effect of diamagnetism on the number of observable hydrogen lines in plasmas; 3) influence of magnetic-field-caused modifications of trajectories of plasma electrons on the width of hydrogen/deuterium spectral lines: applications to white dwarfs; 4) Stark broadening of hydrogen/deuterium spectral lines by a relativistic electron beam: analytical results and applications to magnetic fusion; 5) counterintuitive dependence of the dynamical Stark width of hydrogenic spectral lines on the electron density.
Distinguishing cospectral quantum graphs by scattering
Authors: Mugnolo Delio , Pivovarchik Vyacheslav
Published: February 2023

We propose a simple method for resolution of cospectrality of Schrödinger operators on metric graphs. Our approach consists of attaching a lead to them and comparing the S-functions of the corresponding scattering problems on these (non-compact) graphs. We show that in several cases—including general graphs on at most six vertices, general trees on at most nine vertices, and general fuzzy balls—eigenvalues and scattering data are together sufficient to distinguish cospectral metric graphs.
Validation of the fractional exhaled breath temperature measurement: reference values
Authors: Huljev Šipoš Ivana , Šipoš Kristijan , Steiner Justinija , Grubić Rotkvić Petra , Ljubičić Đivo , Šola Ana Marija , Lozo Vukovac Emilija , Kereš Tatjana , Plavec Davor
Published: February 2023

Exhaled breath temperature (EBT) is a known biomarker of inflammation and airways blood flow. As opposed to previous studies, we were able to measure temperature of separate fractions of exhaled breath (fEBT) (those from the peripheral and central airways). The aim was to validate the fEBT measurement method to determine the reference values and the influence of endogenous and exogenous factors on fEBT in healthy subjects. This cross-sectional study included 55 healthy adults in whom fEBT was repeatedly measured, two days in a row, using a FractAir® device. Also, basal metabolic rate, level of physical activity, distance from the main road, outdoor and ambient temperature, air pressure and humidity, haematology and inflammation markers, lung function, cumulative EBT and body temperature at characteristic points on the body were measured. The results showed that fEBT from central airways was lower compared to fEBT from the periphery and that fEBTs were not related to body temperature (p > 0.05 for all). We also showed repeatability of fEBT measurements for two consecutive days. All EBT fractions correlated significantly with ambient temperature (<0.01). No associations of fEBT with other personal and external factors were found using multivariate analysis. At room temperature of 22 °C, the physiological temperature values of the first fraction were 23.481 ± 3.150 °C, the second fraction 26.114 ± 4.024 °C and the third fraction 28.216 ± 3.321 °C. The proposed reference values represent the first part of validation of fEBT as the method for the use in clinical practice.
Coral recruitment and its relationship to hard coral cover in the Derawan Islands, East Kalimantan
Authors: Giyanto  , Dewi R , Azkiyah B U
Published: February 2023

Coral recruitment is the process when coral larvae settle to the substrate and establish themselves as a reef community. The success of coral recruitment is very important for the sustainability of coral reefs in an area, including the Derawan Islands which develop underwater tourism. Observations on coral reef recruitment were carried out in the Derawan Islands. This study aimed to determine the density of coral recruitment, hard coral cover, and the relationship between coral recruitment and hard coral cover. Data were collected using the Underwater Photo Transect method at 11 stations in the Derawan Islands. The results showed that coral recruitment in the Derawan Islands was low, ranging from 1.41 to 3.13 colonies.m−2. Hard coral cover was categorized as “moderate” with an average of 28.04% (+SE=3.63%). The relationship between coral recruitment and hard coral cover occurred for medium-sized juvenile corals (3-6 cm). Their negative relationship was shown by the presence of more medium-sized juvenile corals in areas with lower hard coral cover. The large availability of stable substrates such as DCA in areas with low hard coral cover can increase the potential for coral reef ecosystems to recover naturally.
Dissolved Pb and Cd Distribution in Cengkok Nearshore of Banten Bay, Indonesia: Processes and Mechanisms
Authors: Pramadhana D , Prartono T , Sulistiono
Published: February 2023

The onshore of Banten Bay has been an active zone with settlements, industries, and ports that potentially release heavy-metal containing waste. This study aims to explain the extent to which Pb and Cd may disperse in the Cengkok nearshore of Banten Bay, Indonesia. Water samples were collected monthly from April to September 2019. Analysis of dissolved heavy metals followed the APHA 2012 procedure. The water quality conditions of the Cengkok nearshore varied during the study period. The distribution of dissolved Pb and Cd in April, June, July, and August are generally undetected although they were found in May ranging <0.002 - 0.011 mg/L Cd and <0.002 - 0.008 mg/L Pb. In September, Cd and Pb were found at all locations varying 0.007 - 0.014 mg/L and 0.004 - 0.042 mg/L, respectively. Cd and Pb distribution patterns varied and could indicate both the riverine effect and coastal processes. Cd and Pb were found discontinuously and disperse differently, indicating the effect of monthly seasons and coastal dynamics.
Epipelic diatom assemblages to determine water quality in the Tuntang River downstream, Demak, Central Java
Authors: Al Falah M H , Soeprobowati T R , Hadiyanto
Published: February 2023

Tuntang River downstream, located in the Demak Regency, Central Java, frequently experiences floods caused by sedimentation, which has occurred continuously since 1970. Changes in land use resulted in ample surface runoff water. The phenomenon affects society’s activities around the Tuntang River downstream which can hinder their activities. The study aimed to analyze diatoms with a biological index and investigate their effect on water quality. Diatoms are one of the bioindicators describing water quality in the river. The sampling technique was used through purposive sampling by selecting four stations along the Tuntang River downstream. The extraction method of sediment was carried out with HCl and H2O2as the solution. The results showed 59 species with 38363 individuals/gram from all research stations. The results showed the highest diversity index (H’) at station 4 (2.96), the highest uniformity index (e) at station 3 (0.68), and the highest dominance index (D) at station 1 (0.11), respectively.Nitzschia paleaindicates the waters containing high C organic and meso-eutrophic based on the dominant species. The results’ findings are expected to become references for river management in the Tuntang River downstream.
The offshore Foraminifera of the Togean Islands, Tomini Gulf; distribution and ecological significance
Authors: Rositasari R , Witasari Y , Wibowo S P A , Hayati N
Published: February 2023

The hydrological complexity, the gulf shape, and the undeveloped geological setting of the Togean Islands in the middle of the waters assembled the area to be such an interesting place to discover its ecological uniqueness. Foraminifera was widely used as proxies for various ecological aspects. Real time and retrospective studies of the vertical and horizontal distribution of foraminiferal communities on such waters are the reflection of many ecological factors in the area. The purpose of the Foraminiferal research on the offshore Togean Islands is to discover the ecological roles that directly and indirectly affect the characteristics of the vertical and horizontal distribution. The study was also referring various ecological aspects from previous studies at the research site. Sampling was carried out in September 2015 using the Baruna Jaya VIII RV in the Togean Islands waters, Tomini Gulf, through a gravity core. Foraminifera analysis was carried out at four core samples from the adjacent waters of four reef islands; Una-una, Pengempang, Togean, and Kalla at 5 m to 455 m water depths. Core samples of various lengths, from 8 cm to 34 cm were dominated by planktonic foraminifera. The dominance of planktonic taxa in reef waters indicates a robust oceanic influence to the reef islands. Upwelling events in several locations in the region as well as volcanic processes that are ongoing also play a role in the distribution of the bulk of planktonic taxa in the reef waters of Togean Islands.
Identification of eddy-induced chlorophyll in the Northeastern Natuna Sea
Authors: Mujiasih S , Soeyanto E , Hafizt M
Published: February 2023

We detected a robust cyclonic eddy in the northeastern Natuna Island in the Northwest Monsoon during an extremely negative El Niño-Southern Oscillation (ENSO) period (i.e., extreme La Niña event) using the Copernicus Marine Environment Monitoring Service (CMEMS) reanalysis results. In the intense La Niña event from 1999 to 2001, we also found an increase in the abundance of chlorophyll coincided with the eddy strength pattern using the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data. Furthermore, this chlorophyll intensity may be related to the upwelling of water mass to the surface at the eddy’s center. The intensification of chlorophyll compared to the average value at the corresponding year is 83,4% (1999), 37.8% (2000), 37.3% (2008), and 72.5% (2011). In this paper, we revisit the identification of solid eddies in extreme La Niña events from 1999 to 2012 and further discuss the mechanism of the relationship between chlorophyll intensity and eddy strength, especially during the months of the extreme La Niña event.
Seasonal spreading and age of Citarum River water in the Jakarta Bay
Authors: Soeyanto E , Morimoto A , Hayami Y , Sudaryanto A
Published: February 2023

Citarum River is considered one of the most polluted rivers in the world, which could contribute to Jakarta Bay’s environmental quality. The purpose of this study is to predict the impact of the Citarum River on Jakarta Bay’s pollution by understanding the river’s seasonal spreading and water age. This study uses numerical ocean modeling for the largest river flowing to Jakarta Bay in 2016. The constituent-oriented age and residence time theory (CART), which supports a solution to the environmental problems in this bay, was employed to comprehend long-term river water movement. The CART’s water age calculation module is embedded in a numerical hydrodynamic model to generate the temporal variation and spatial distribution of Citarum River water. Hydrographic observations were used to validate the model in February, May, and November this year. Surface current distribution patterns, which were controlled by surface wind stress and river discharge, determined the seasonal spread of the Citarum River water distribution. Meanwhile, the average age of Citarum River water in Jakarta Bay was a few days.
Seasonal variation of mixed layer depth and thermocline thickness from the ctd argo float data in the Southern Makassar Strait
Authors: Putra D R , Natih N M N , Purwandana A
Published: February 2023

The Makassar Strait (MS) is directly connected to the Sulawesi Sea in the north and the Java Sea and the Flores Sea in the south and is the main route of Indonesia Throughflow(ITF). Hence Stratification of water mass in the MS is influenced by the dynamics of these waters. This study aims to describe seasonal variations of the mixed layer depth and the thermocline thickness, identify ITF water masses, and the occurrence of coastal upwelling in the southern part of the MS. The results show that the North Pacific water origin of North Pacific Subtropical Water (NPSW) and North Pacific Intermediate Water (NPIW) are dominant, with a maximum salinity characteristic of 34.6-34.7 psu in the thermocline layer and a minimum salinity of 34.5 psu in the intermediate layer. However, near-surface fresh Java Seawater appears to be dominant during the northwest monsoon (NWM-DJF) period. Seasonal variation of the mixed layer depth is much deeper (93m) and vertical gradient of temperature and salinity are much stronger due to the presence of fresh Java Sea water advected by the eastward Java Monsoon Current. However, during the southeast monsoon (SEM-JJA) period the mixed layer depth is much shallower and the thermocline layer is much thicker (198 m), Associated with much stronger ITF and upwelled colder water from the upwelling area. The coastal upwelling event during the SEM period in the study are is characterized by an increase of isotherm of 25 °C, isohaline of 34.0 psu, and isopycnal of 22.0 kg/m3 from about 75 m depth to the sea surface layer.
Simulated circulation and trajectory analysis in the Makassar Strait
Authors: Noorsyoda R M A , Naulita Y , Apriansyah  , Natih Nyoman M
Published: February 2023

Makassar Strait conveys the main Indonesian Throughflow (ITF) pathway, as part of the global thermohaline circulation transferring heat and freshwater fluxes from the Pacific Ocean to the Indian Ocean. Dynamics and variability of the ITF and the monsoon winds system influence significantly marine ecosystem in the Indonesian Seas. The study aims to analyze sea surface circulation patterns and particle trajectories in the Makassar Strait by developing a simulation of the CROCO’s 1/36º regional general circulation model between 2017-2018. The results revealed the dynamics of near-surface layer (0 – 50 m depth) varied seasonally. The magnitude of surface current was about 0.6 m/s during the peak of northwest monsoon (NWM) flowing northward and reverse southward during the peak of southeast monsoon (SEM). The magnitude of the current intensified up to 1 m/s in the subsurface at Labani Channel and persistent flows to the southward. The thermocline transport volume was maximum during SEM with average transport about -11.00 (±1.54) Sv. The analysis shows that the particles near Balikpapan coast spreaded slowly to the north, then rotating at the center of the strait and spreaded according to the NWM and SEM.
The ocean response to El Nino Southern Oscillation (ENSO) in the Bali Sea: a model study
Authors: Adhinugraha F A C , Atmadipoera A S , Hartanto M T
Published: February 2023

The Bali Sea (BS) is connected to the Java Sea and Makassar Strait in the north and is one of the main outflow straits of the Indonesian Throughflow (ITF) in Lombok Strait (LS). Local ocean dynamics and their variability may be controlled significantly by the ITF. This study aims to investigate the interannual variation of circulation, mixed layer depth, and isotherm of 20°C, by performing a simulation of fine- a resolution 1/84° ocean circulation model of CROCO between 2010-2020 with a focus on El Nino 2015 (EN2015) and La Nina 2020 (LN2020) events. The model validation reproduces well the satellite-derived SST and SSH dataset with a correlation coefficient of >0.9. The model demonstrated an anti-clockwise circulation of the ITF in the BS, entering via the northern and exiting into the LS via the southern area. This circulation changes drastically during the ENSO event, where the ITF transport inflow is weaker and shallower during EN2015, compared to a much stronger and deeper ITF inflow during LN2020. Accordingly, shallower mixed layer depth and depth of isotherm of 20°C are found during EN2015, and vice versa. Coherence of these parameters with NINO3.4 is very significant (>-0.89) with a phase lag of 1.7 months.
Distribution of phytoplankton diversity and abundance in Manokwari waters, West Papua - Indonesia
Authors: Badila A , Matulessy M , Kolibongso D
Published: February 2023

The distribution of phytoplankton diversity and abundance found in coastal areas is usually different from the open seas due to changes in environmental parameters. The study was conducted to provide data on the distribution, diversity (H’ and Simpson’s indices), and abundance of phytoplankton in five different stations and to identify some influencing factors using canonical correspondence analysis (CCA). Three stations (Arowi, Rendani, and Maruni) are inside an embayment area and close to the center of human activity; the other two stations (Sidei and Undi) are off the bay. Total cell abundance ranged from 1,680 to 10,260 cells.m−3. The Baccilariophyceae were the most diverse and numerous classes. There were 17 phytoplankton taxa members of the classes of Bacillariophyceae (11 taxa), Dinophyceae (2 taxa), Chlorophyceae (2 taxa), and Cyanophyceae (2 taxa). The phytoplankton from Arowi station showed highest diversity (H’ = 2.38), followed by Sidey (H’ = 2.24), Undi (H’ = 2.10), Rendani (H’ = 2.06), and Maruni stations (H’ = 1.83). The ecological indices of Arowi, Sidey, Undi, and Rendani indicated quite stable communities, while Maruni was indicated unstable communities. Several species of blooming and toxic phytoplankton were found at all stations, one of which was Pseudonitczhia sp. CCA analysis showed that salinity, temperature, pH, phosphate, and current are limiting factors for the distribution and abundance of phytoplankton in Manokwari waters.
Genetic diversity of six populations of Ajamaru rainbowfish (Melanotaenia ajamaruensis) with different breeding ratios
Authors: Hayuningtyas E P
Published: February 2023

The Ajamaru rainbowfish (Melanotaenia ajamaruensis) is a West Papuan endemic and has been successfully cultured. The study aims to determine the genetic diversity of the Ajamaru rainbowfish ornamental fish populations that breed with differences in the breeding ratio to offspring. Tail fin samples were taken from six populations of Ajamaru rainbowfish consisting of 2 generations for DNA extraction. Three-broodstock populations (1:1, 1:2, and 3:1) spawn at seven months old, and three offspring populations. The method used was Randomly Amplified Polymorphic DNA (RAPD) analysis, primary screening using 20 primers, and four selected primers (OPG 2, OPB 6, OPH 5, and OPZ 9). Data analysis used TFPGA software to generate genetic diversity values in heterozygosity and polymorphism. The results showed the lowest genetic diversity in population 1, with polymorphism (46.99%) and heterozygosity 0.1894. The highest genetic diversity was in population 4, with descendants with polymorphism (78.31%) and heterozygosity of 0.2922. Relationships among 6 Ajamaru rainbowfish populations formed two clades based on their generation. Improving genetic quality in the breeding of Ajamaru rainbowfish can be done through selective breeding with a breeding ratio of 1:1 or the full-sib broodstock for higher genetic diversity values.
The use of stereo cameras and artificial intelligence data to support capture fisheries landing data monitoring
Authors: Wibowo S , Hargiyatno I T , Faizah R , Natsir M
Published: February 2023

Reliable data and data collection are important key factors in realizing sustainable fisheries management. Landing data collected by the fishing port authority through has issues with coverage and accuracy. The fast development of image processing and artificial intelligence (AI) analysis opens the possibilities of automatic catch monitoring and data collection in the fishing port. This paper aims to develop a catch data collection program in fishing ports based on stereo camera video monitoring which AI processes. The first version of the devices, FishQi-L (Fish Quantitative Intelligence in Landing site), was developed. FishQi-L consisted of a set stereo camera and a pre-programed JETSON Nano image/video processor. The stereo camera allows image size quantification, size estimation, and spatial mapping capabilities. FishQi-L was able to detect the character and dimensions of objects, the trial object in Pekalongan was “Basket” with mean average precision (mAP) of the detection was 84% and 0.4387 losses. To increase the accuracy and reliability of the systems, we need to increase the number of data and data training iterations.
The effectiveness of brood stock management in captive breeding of marine ornamental Fish
Authors: Hadie L E , Kontara E K M , Kusdiarti  , Putri A W M
Published: February 2023

Nowadays, the trade in marine ornamental fish is growing to be a multimillion-dollar industry. Because marine ornamental fish are successfully being bred in captivity, the industry can flourish. The breeding process is progressively applied through collecting fish from their natural habitat, inventory and domestication. An important stage in the breeding process of marine ornamental fish is the efficient management of brood stocks. A considerable number of initial populations become one of the keys to success in breeding marine ornamental fish. The principle of high genetic diversity in populations at the beginning of the collection is also an important indicator of the sustainability of the breeding process. The study aims to evaluate the management of brood stocks for marine ornamental fish in captive breeding. The observed parameters are the number of brood stocks populations, effective population size, and the utility of inbreeding in a population. The success of its cultivation is determined by the genetic diversity in the basic population which needs to be monitored from the start of the captive program.
Tilapia growth performance and body physical index given synbiotic feed at different salinities
Authors: Rahmi R , Akmal A , Nisaa K , Sudrajat I , Relatami A N R , Tampangallo B R , Ikbal M
Published: February 2023

Tilapia saline is a fishery commodity with a fairly large market prospect but has problems with slow growth performance, affecting the speed of its production. This study aims to determine the best growth performance with the body’s physical index of tilapia at different salinities using the synbiotic feed. The synbiotic feed is given with probiotic Bacillus subtilis 105 CFU/mL density and banana flour prebiotic 1%. This study used five different salinity treatments (A. 0 ppt; B. 5 ppt; C. 10 ppt; D. 15 ppt; E. 20 ppt) with a weight of tilapia 3,35±0,5g each 20 fish/aquarium. The results showed that mortality, FCR, weight gain (WG), and feed efficiency showed significant results in the 15 ppt salinity treatment compared to other treatments. The HIS, DSI, and Condition Factor (K) values were not significantly different (P>0,05), but the IPF values were significantly different (P<0,05) from other treatments. The average treatment at 15 ppt salinity gave optimal growth performance and physical body index, especially IPF in tilapia fry.
Applying edible coating based on chitosan and liquid smoke on the quality and microstructure of barracuda fish sausage (Sphyraena sp.)
Authors: Swastawati F , Antami H A , Purnamayati L
Published: February 2023

Barracuda fish has abundant nutritional value and can be processed into a variety of products, including sausages. This research has been carried out to improve the quality of barracuda fish sausage during storage. Chitosan was chosen as an edible coating because of its antibacterial properties. However, it cannot dissolve at neutral pH, so the liquid smoke is used as a solvent and is expected to give maximum results. The best formulation of edible coating is 1% chitosan and 3% liquid smoke, applied to the sausage by immersion, then stored at cold temperature ± 5°C for 12 days with test intervals of 0, 4, 8, and 12 days. Edible coating treatment had a significant effect (p<0.05) on product quality. Fish sausage with coating has a more even and slightly loose microstructure. The structure without coating forms lumps and more cavities. The gel strength of coated sausage until day 12 was higher (2624.29 ± 9.02) than sausage without coating, on day 12, the sensory value on coated sausage was 7.35. The moisture and protein content of sausage coating on day 12 is 67.94% and 11.80%, and the total bacteria is 4.34 colonies/g. Barracuda fish sausage with edible coating has met the standard of SNI 7755-2013.
Changes in mineral content and vitamin A of cobia (Rachycentron canadum) due to the steaming process
Authors: Nurjanah  , Suwandi R , Aisyah E N , Hidayat T
Published: February 2023

Cobia (Rachycentron canadum) is a commodity that has the potential to be cultured, but little information about the nutritional content of those fish. This study aimed to determine the effect of the steaming process on the chemical composition, mineral, and vitamin A of cobia from Balai Besar Pengembangan Budidaya Laut Lampung. Steaming lowered the chemical composition of cobia meat including moisture content, ash, fat, and protein on a dry based. The steaming process affected the decreasing vitamin A, and minerals content (calcium, sodium, phosphorus, magnesium, and zinc) and showed no effect on iron and potassium content. The highest mineral loss happened after steaming to magnesium (140 mg/100 g) and the lowest one was iron (0.004 mg/100 g). Steaming lowered the vitamin A content of cobia meat up to 42.36%.