bluuebunny/crossref_metadata_2025 huggingface dataset:
Local structural investigation of non-crystalline materials at high pressure: the case of GeO2 glass
Authors: Hong Xinguo , Newville Matt , Ding Yang
Published: February 2023

Local structures play a crucial role in the structural polyamorphism and novel electronic properties of amorphous materials, but their accurate measurement at high pressure remains a formidable challenge. In this article, we use the local structure of network-forming GeO2 glass as an example, to present our recent approaches and advances in high-energy x-ray diffraction, high-pressure x-ray absorption fine structure, and ab initio first-principles density functional theory calculations and simulations. Although GeO2 glass is one of the best studied materials in the field of high pressure research due to its importance in glass theory and geophysical significance, there are still some long-standing puzzles, such as the existence of appreciable distinct fivefold [5]Ge coordination at low pressure and the sixfold-plus [6+]Ge coordination at ultrahigh pressure. Our work sheds light on the origin of pressure-induced polyamorphism of GeO2 glass, and the [5]Ge polyhedral units may be the dominant species in the densification mechanism of network-forming glasses from tetrahedral to octahedral amorphous structures.
An ab initio study of catechol sensing in pristine and transition metal decorated γ-graphyne
Authors: Dewangan Juhee , Mahamiya Vikram , Shukla Alok , Chakraborty Brahmananda
Published: February 2023

Catechol is a toxic biomolecule due to its low degradability to the ecosystem and unpredictable impact on human health. In this work, we have investigated the catechol sensing properties of pristine and transition metal (Ag, Au, Pd, and Ti) decorated γ-graphyne (GY) systems by employing the density functional theory and first-principles molecular dynamics approach. Simulation results revealed that Pd and Ti atom is more suitable than Ag and Au atom for the decoration of the GY structure with a large charge transfer of 0.29e and 1.54e from valence d-orbitals of the Pd/Ti atom to the carbon-2p orbitals of GY. The GY + Ti system offers excellent electrochemical sensing towards catechol with charge donation of 0.14e from catechol O-p orbitals to Ti-d orbitals, while the catechol molecule is physisorbed to pristine GY with only 0.04e of charge transfer. There exists an energy barrier of 5.19 eV for the diffusion of the Ti atom, which prevents the system from metal–metal clustering. To verify the thermal stability of the sensing material, we have conducted the molecular dynamics simulations at 300 K. We have reported feasible recovery times of 2.05 × 10−5 s and 4.7 × 102 s for sensing substrate GY + Pd and GY + Ti, respectively, at 500 K of UV light.
The rotational rocket
Authors: Mungan Carl E
Published: February 2023

A rotational rocket is the angular analogue of the familiar translational rocket. It spins about an axis fixed in position, as a result of the ejection of matter (typically in the form of one or more fluid jets) tangentially from its rim. Examples include a rotary lawn sprinkler, Hero’s engine, or a carousel off of which balls are thrown. The thrust equation is developed starting from Newton’s second law for rotations. Special cases that could be used in class or homework in an introductory mechanics course are discussed.
The role of laser chirp in relativistic electron acceleration using multi-electron gas targets
Authors: Grigoriadis A , Andrianaki G , Tatarakis M , Benis E P , Papadogiannis N A
Published: February 2023

The role of multi-10 TW chirped laser pulses interacting with N2 gas jet targets, as a test case for multi-electron targets, is experimentally examined. Complementary measurements using He gas jet targets, which are fully ionized well before the laser pulse peak, are also presented for comparison with the measurements for the multi-electron N2 targets. It is found that for both gases positively chirped laser pulses accelerate electrons more efficiently compared to the Fourier transform-limited and negatively chirped pulses. Furthermore, multi-electron targets offer additional electron injection mechanisms for efficient electron acceleration as a function of the chirp, due to the dynamic ionization of inner-shell electrons near the peak of the laser pulse. Finally, we show that the background plasma density value plays a critical role in the efficient acceleration of positively chirped pulses as well as in the tuning of the positive chirp value for maximizing the electron energy. We clearly observe that larger plasma density values require higher positive chirp values for efficient electron acceleration.
A novel multigranulation roughness of bipolar fuzzy set over dual universes and its applications
Authors: Mubarak Asad , Shabir Muhammad , Mahmood Waqas
Published: February 2023

In the world, multigranulation rough sets and bipolar fuzzy sets are the practical tools for dealing with the uncertainty, vagueness, and imperfection that frequently arise in decision making problems. The goal of multigranulation rough sets is to characterize uncertain situations in various granularity spaces, whereas bipolar fuzzy sets (BFSs) have the capacity to handle uncertainty as well as informational bipolarity in a variety of contexts. This article examines the optimistic multigranulation rough approximation of a BFS in the light of multi-soft binary relations across two different universes. We investigate some algebraic properties of our newly constructed optimistic multigranulation rough set scheme. Measures of accuracy and roughness are also covered in this paper. Finally, two decision algorithms are designed with respect to aftersets and foresets that are applied to a decision making problem in disease diagnoses, and the applicability of the method is illustrated by a numerical example.
ITO/MgSe interfaces designed as gigahertz/terahertz filters
Authors: Almotiri R A , Qasrawi A F
Published: February 2023

Herein a new class of MgSe gigahertz/terahertz band filters operatives in the frequency domain of 1.0 GHz-1.86 THz is fabricated and experimentally tested. MgSe band filters are coated onto glass and indium tin oxide (ITO) substrates by the thermal evaporation technique under a vacuum pressure of 10−5 mbar. Thin films of MgSe are structurally, morphologically, compositionally, optically and electrically characterized. It is observed that ITO substrates induce the growth of monophasic of MgSe, enhances the crystallinity of the films and blueshifts the energy band gaps of MgSe. Practical applications were verified by impedance spectroscopy technique through imposing an ac signal of driving frequency in the domain of 10.0 MHz-1.8 GHz between the terminals of ITO/MgSe/Au (IMA) devices. It is observed that the IMA devices exhibit negative capacitance effect. Analysis of the cutoff frequency spectra has shown that IMA devices can reveal wide range of tunability in the gigahertz frequency domain. In addition, the cutoff frequency spectra show values reaching ∼1.86 THz for signals of driving frequencies of ∼1.0 GHz. Evaluation of the magnitude of the reflection coefficient spectra and return loss spectra for these devices show that the IMA devices can perform as bandstop filters with return loss values exceeding 20 dB at 1.0 GHz. The features of the ITO/MgSe/Au devices are appropriate for the 5 G/6 G technology needs indicating that the device can be employed in communication technology and other gigahertz/terahertz applications.
Classical fermion dynamics in presence of non abelian monopoles
Authors: Morano Alejandro , Santillán Osvaldo P
Published: February 2023

In the present letter, the dynamics of a spin one-half particle with non abelian charge, interacting with a non abelian monopole like configuration, is studied. In the non spinning case, these equations correspond to the Wong ones S Wong (1970, Il Nuovo Cimento LXV, 4 689), and the associated dynamics has been extensively investigated in I Alekseev (1988, Theoret. and Math. Phys.
77 1273), L G Feher (1984, Acta Physica Polonica
15 920). The classical limit of a spinning particle in an abelian was considered in A Davis and W Perkins (1989, Phys. Lett. B
228 37), where an interpretation of the celebrated Callan-Rubakov effect C G Callan (1982, Phys. Rev. D
26 2058); V A Rubakov (1982, Nucl. Phys. B
203 311), V A Rubakov and M S Serebryakov (1983, Nucl. Phys. B
218 240); V A Rubakov (1981, JETP Len.
33 644). was obtained in purely classical terms The present work studies an interpolating situation, in which spin and non abelian charges are turned on. The corresponding equations are obtaining by taking into account some earlier works about spinning particles N Linden, A Macfarlane and J van Holten Czechoslovak (1996, J. Phys.
46 209), A Barducci, R Casalbuoni and L Lusanna (1977, Nuclear Physics B
124 93, A P Balachandran Per Salomson, B -S Skagerstam, and J -O Winnberg (1977, Phys. Rev. D
15 2308). The conservation laws are studied in this context, and it is found that energy and some generalization of angular momentum are conserved just in particular limits. This is a reflection that the non abelian interaction contains gauge field quartic interaction, which spoils the symmetries leading to these conservation laws. The precession of the particle is analyzed and compared with its abelian counterpart in this limit.
Trajectories of directed lattice paths
Authors: Janse van Rensburg EJ
Published: February 2023

The distribution of monomers along a linear polymer grafted on a hard wall is modelled by determining the probability distribution of occupied vertices of Dyck path and Dyck meander models of adsorbing linear polymers. For example, the probability that a Dyck path passes through the lattice site with coordinates

(
⌊
ϵ
n
⌋
,
⌊
δ

n

⌋
)

in the square lattice, for 0 < ϵ < 1 and δ ≥ 0, is determined asymptotically as n → ∞ and this uncovers the probability density of vertices along Dyck paths in the limit as the length of the path n approaches infinity:

P

(
D
)

(
ϵ
,
δ
)
=

4

δ

2

π

ϵ

3

1
−
ϵ

3

e

−

δ

2

/

ϵ
(
1
−
ϵ
)

.

The properties of a polymer coating of a hard wall and the density or distribution of monomers in the coating is relevant in applications such as the stabilisation of a colloid dispersion by a polymer or in a drug delivery system such as a drug-eluding stent covered by a grafted polymer.
Magnetic field control and swift heavy ion beam assisted tuning of resistive switching properties of BSFO/CFO/LNO heterostructures
Authors: Thankachen Nisha , Chhaya U V , Tripathi A , Joshi U S
Published: February 2023

Resistive switching (RS) behavior in mixed oxide insulators has shown a great promise as memristors or non-volatile resistive random-access memory (RRAM) applications. For dilute magnetic oxide multilayers, a novel approach of controlled defects induced and the magnetic field control of RS behavior is proposed. Resistive switching in Bi0.6Sr0.4FeO3 /CoFe2O4 /LaNiO3 (BSFO/CFO/LNO) multilayer heterostructures has been investigated as a case study. All oxide junctions consisting of conducting LaNiO3 (LNO) bottom electrode and BSFO-CFO active layers were fabricated by using chemical solution deposition. A set of samples were irradiated with 150 MeV Ag11+ ions for three different ion fluence of ∼1 × 10+11 ions cm−2, 1 × 10+12 ions cm−2 and 5 × 10+12 ions cm−2. Polycrystalline phase pure films with smooth, crack free surfaces were observed for pristine and irradiated samples. Optical spectroscopy revealed a decrease in the transmittance upon increasing ion fluence due to increase in the light scattering centres. The optical band gap showed a systematic decrease from 2.09 eV to 1.65 eV with increasing ion fluence. Room temperature I-V characteristics showed consistent and pronounced bipolar switching for all samples below ± 5 V. Upon applied magnetic fields of 0.58 T, the resistive switching ratios were found to increase significantly and were further tuned by 150 MeV Ag11+ ion beam irradiations. The magnetic field control of electrical transport properties in the controlled defect assisted oxide heterojunctions offers new insights to the existing understanding of oxide-based RS mechanism.
Analysis of thermodynamic resistive switching in ZnO-based RRAM device
Authors: Bature Usman Isyaku , Nawi Illani Mohd , Khir Mohd Haris Md , Zahoor Furqan , Ba Hashwan Saeed S , Algamili Abdullah Saleh , Abbas Haider
Published: February 2023

Due to its excellent performance, resistive random access memory (RRAM) has become one of the most appealing and promising types of memory. However, RRAM has significant problems concerning understanding and modelling the resistive-switching mechanism, despite being very promising from the perspectives of scalability and techniques. This paper presents an analysis of thermodynamic resistive switching and fundamentals of thermal energy flow in a ZnO-based RRAM stack. The field and thermal energy flow within the device are analysed using the thermodynamic process. The influence of parameter variations during the SET and RESET operations is shown and their effect on the switching characteristic is characterized. The real I-V characteristics show fixed current vibrations and field-driven ion transport is evidenced and more prominent at higher currents. It shows that the nucleation of the filament as well as the growth of the gap complements the increase in the free energy (FE) of the system. These studies contribute to better comprehension and account for SET-RESET characteristics, rightly unfolding the thermal energy flow during dynamic switching operations that causes device degradation and allowing stability for future data storage projections.
Differential cross sections for projectile scattering angle in proton-helium collision at intermediate energies
Authors: Igarashi A , Kato D
Published: February 2023

The collisions between proton and helium are treated with a semi-classical atomic orbital expansion for proton incident energies 5–150 keV considering two-electrons explicitly. Differential cross sections with respect to the projectile scattering angle are calculated for elastic scattering, 21S and 21P excitation, single electron capture, and single ionization. The agreement with experiments are mostly good, but non-negligible discrepancies are seen for the elastic scattering and the single electron capture with target excitation.
Constraints on dark matter scattering with long lived mediators from observations of the Sun with the Fermi Large Area Telescope
Authors: Serini D. , Loparco F. , Mazziotta M.N. , De Gaetano S. , Di Venere L. , Gargano F. , Lorusso L. , Panzarini G. , Pillera R.
Published: February 2023

The Sun represents a promising target for indirect dark matter searches, as dark matter particles from the Galactic halo can be gravitationally trapped in its core or in external orbits, and their annihilations can lead to final states with standard model particles that are able to reach the Earth. In this work we have considered a scenario in which dark matter particles can annihilate into pairs of long-lived mediators, which in turn can escape from the Sun and decay into pairs of gamma rays or into the bb̅, τ
+
τ
-, μ
+
μ
- channels, with the production of gamma rays in the final states. All these processes are expected to yield an excess in the energy spectrum of gamma rays towards the Sun. We have therefore analyzed the data collected by the Fermi Large Area Telescope during its first 13.5 years of operation, searching for possible excesses in the solar gamma-ray spectrum. Since no statistically significant excess is found, we have set constraints on the dark matter-nucleon scattering cross sections in both the spin-dependent and spin-independent cases. For all the mediator decay channels explored and for dark matter masses between a few GeV/c2 and 1 TeV/c2, we have found that the upper limits on the spin-dependent and spin-independent cross sections are in the ranges from 10-45 to 10-39 cm2 and from 10-47 up to 10-42 cm2, respectively.
A closer look at the seesaw-dark matter correspondence
Authors: Coy Rupert , Gupta Aritra
Published: February 2023

In an earlier work [1], we showed that in very simple neutrino portal-like
extensions of the Standard Model it is possible to achieve a one-to-one correspondence between
dark matter physics and the seesaw parameters controlling the genesis of neutrino masses.
Notably, this can occur both when the dark matter is produced via freeze-in and relativistic
freeze-out. In this article, we carry out a detailed phenomenological study of such
scenarios. Specifically, we find the allowed regions for the neutrino portal coupling within which
the correspondence is valid. We further constrain the parameter space from various observational
and theoretical considerations. Within this, we derive the distribution function of a doubly
frozen-in particle in order to more accurately compute its free-streaming horizon.
Variation of UV-A/UV-B daily profiles depending on locations and altitude
Authors: Tyutyundzhiev Nikolay , Angelov Christo , Arsov Todor , Nitchev Hristo , Lovchinov Konstantin , Mutafov Asen
Published: February 2023

Solar UV/visible monitoring has increased its importance in the recent years due to the global warming, unexpected atmospheric anomalies and storms, and the increasing needs for additional human protection. In mountain areas with high elevation the interest to UV irradiation measurements is expected to increase due to atmospheric transparency, however frequent events of lightning and risk of equipment failures has to be taken into account. The cost of the UV measurement systems can be greatly reduced by employing low-cost integrated inexpensive digital sensors with on-chip signal conditioning as detectors which are more convenient for field deployment and outdoor measurements. Thus, a compact portable UV/visible sensor equipment is in great demand for annual solar irradiation monitoring and seasonal all-day measurement campaigns. In this work, we report on the development of an in-house portable UV sensor system based on digital sensors with I2C communication, open-source hardware and software. The developed equipment is based on integrated digital sensors (VEML 6075, TSL 2591). It has been developed by employing Wi-Fi ESP 32 microcontroller, ODROID microcomputer and open-source software (InfluxDB and Grafana visualization tool). We investigate the system performance by measuring daily profiles of UV-B/UV-A irradiation in different locations and under different atmospheric conditions in order to evaluate its feasibility for prevention of humans from UV overexposure during outdoor operations. On-field tests are performed for 2 years in 7 different locations in Bulgaria. Interestingly, in downtown during particular days with high traffic an increased UV scattering and absorption due to urban pollution has been observed.
Preparation and characterization of RF sputtered ZnO layers for application in thin films solar cells
Authors: Spasova S. , Dikov Hr. , Ganchev M.
Published: February 2023

Transparent conductive electrodes (TCO) serve as window and contact layers and they should combine high optical transmittance with low electrical resistivity. Recently ZnO has been considered to be the most promising TCO material in view of cost and properties. Chalcopyrite based solar cells commonly consist of Cu(In,Ga)Se2 (CIGS) absorber layer and a sputter sequence of undoped and doped ZnO layers in a structure: glass/Mo/CIGS/CdS/ZnO/ZnO:Al. In some cases, ZnO plays the role of the buffer layer itself as an alternative of the mostly used toxic CdS. An advanced application of this material is considered to be involving in Organic Solar Cells (OSCs) as Electron Transporting Material (ETM). The work presents fabrication of uniform resistive thin (50-100 nm) undoped ZnO films serving as buffer layers and conductive Al-doped ZnO films (Al:ZnO) with thickness in the range of 100-500 nm. In the latter case the film thickness was optimized to combine high transmittance and low resistivity. Both types of films are with good adhesion and possess a transmittance over 90% in the visible region. Highly transparent bi-layer films (ZnO/ZnO:Al) were finally embedded in the solar cell structure: glass/Mo/CIGS/ZnO/ZnO:Al/Al.
On the relation of the potential energy landscape and the cooperatively rearranging region
Authors: Solunov Hristo
Published: February 2023

In an extension of Adam-Gibbs’ theory, an equation for the measuring the size of cooperatively rearranging region has been found and interpreted as the number of the beads rearranging during the relaxation time. A relation for the partitioning the molecules to the number of the beads has been also suggested. The size of the cooperatively rearranging region has been found to be the molecular basis of the fragility for the glass forming liquids. In the potential eenergy landscape, the maximal number of the potential minima in the configuration space is assumed to be measure of the fragility. Here, a relation between the size of the cooperatively rearranging region and the parameters in the model functions determining the maximal number of the potential minima (inherent structures) is suggested. For the first time the total number of minima per the mole molecule and per mol of the beads are compared. Two of the most fragile liquids, toluene and o-terphenyl are investigated, and it is found that the molecular, the kinetic and the thermodynamic measures for the fragility are correlated with the maximal number of minima in the mol of the beads but not in that of the mol of the molecules.
Cyanide Molecular Laser-Induced Plasma Spectroscopy
Authors: Parigger C G , Helstern C M
Published: February 2023

This work communicates recent measurements of CN in laser-induced plasma. The main goals and objectives comprise (a) exploring CN measurement using optical emission spectroscopy in optical breakdown plasma; (b) determining the effects of laser-induced shockwave for time delays of the order of 1 μs; (c) evaluating the spatial distribution of CN signals; (d) inferring CN temperature distribution; and (e) associating recorded shadowgraphs with laser-spectroscopy results. Q-switched, 150 mJ, 6 ns pulsed Nd:YAG laser radiation at the fundamental wavelength of 1064 nm is used to generate micro-plasma in a gas mixture with ultra-high purity nitrogen and research grade carbon dioxide. The CO2 to N2 molar ratio is 1 to 1 for the gaseous mixture near atmospheric pressure flowing through the chamber. Optical emissions are dispersed by a 0.64-m Czerny-Turner spectrometer and an intensified charge-coupled device records the data along the wavelength and slit dimensions. The analysis utilizes Abel integral inversion techniques for determination of spatiotemporal profiles.
Study of arsenic resonance spectral lines in far UV region from a HFEDL for usage in Zeeman absorption spectroscopy
Authors: Zorina Natalja , Abola Anda , Skudra Atis , Revalde Gita
Published: February 2023

This work is focused on obtaining and analyzing the main spectral characteristics of a high-frequency electrodeless light source filled with arsenic for use in high-precision atomic absorption analyzers. We analyzed the relative intensities of the three arsenic resonance spectral lines 189.0 nm, 193.7 nm, and 197.3 nm in the far UV spectral region, the dependence of the intensity on the applied voltage, the impact of the instrumental function on the emission spectra, the influence of self-absorption and the stability of the radiation. Among others, a deconvolution procedure was implemented to obtain the real shapes of the emitted profiles.
Accurately computed H2–He collision-induced absorption coefficients for modeling of planetary atmospheres
Authors: Gustafsson Magnus
Published: February 2023

Accurate collision-induced absorption profiles for H2–He pairs, in the rototranslational band of H2, are computed accounting for the full anisotropic interaction potential. The calculations are time consuming and complicated compared to those pursued in the isotropic potential approximation. A machine learning approach is implemented in order to produce highly accurate data on a dense frequency grid, by combining data computed in the full calculation with those from the isotropic approximation. Thus an extensive, highly accurate, data base can be obtained for a set of frequencies, temperatures, and ortho-H2/para-H2 fractions, appropriate for use in modeling of planetary atmospheres, in particular of the gas giants.
Reconstruction of charged tracks with Timepix4 ASICs
Authors: Akiba K. , van Beuzekom M. , van Beveren V. , Byczynski W. , Coco V. , Collins P. , Dall'Occo E. , Dumps R. , Evans T. , Geertsema R. , Gkougkousis E.L. , Halvorsen M.M. , van der Heijden B. , Heijhoff K. , Lemos Cid E. , Pajero T. , Rolf D. , Schindler H.
Published: February 2023

The spatial and temporal performance of a four-plane system
composed of silicon sensors bump-bonded to Timepix4 ASICs is
assessed with a 180 GeV/c mixed hadron beam at the CERN SPS and
reported in detail. Particle tracks are reconstructed using
time-space measurements from the four detector planes, two
100 μm planes perpendicular to the beam and two 300 μm
sensors under an angle of 9°. The spatial hit resolution
is assessed to be (15.5 ± 0.5) μm and (4.5 ± 0.3) μm
for 100 μm and 300 μm thick sensors, respectively.
The timestamps from the detectors are also measured with fine
precision, yielding time resolutions of (452 ± 10) ps,
(420 ± 10) ps, (639 ± 10) ps, (631 ± 10) ps for the two
100 μm and two 300 μm thick sensors respectively.
These measurements are combined to a track time resolution of
(340 ± 5) ps. The design of the detector system is described
together with its data acquisition system, operational
infrastructure, and dedicated software.
Inverse scattering transforms for the nonlocal Hirota–Maxwell–Bloch system
Authors: An Ling , Chen Yiren , Ling Liming
Published: February 2023

The Hirota and Maxwell–Bloch (H-MB) system is a mathematical model that can be used to describe the wave propagation in an erbium-doped nonlinear fiber with higher-order dispersion. By extending the parameter ω in the H-MB system to the complex domain, all the nonlocal forms of the H-MB system, including the reverse-space-time, complex reverse-space, complex reverse-time, complex reverse-space-time H-MB systems, are found. Then the Riemann–Hilbert problem of the nonlocal H-MB system is established to analyze the corresponding inverse scattering problem and construct the corresponding soliton solutions. When N = 1, the singularity of the one-soliton solutions of each nonlocal H-MB system is analyzed. When N = 2, we take the nonlocal reverse-space-time H-MB system and the nonlocal complex reverse-time H-MB system as examples, showing that a two-soliton can also be regarded as a superposition of two single-soliton in the nonlocal cases as

|

t

|

→
∞

.
Clusters in the critical branching Brownian motion
Authors: Ferté Benoît , Le Doussal Pierre , Rosso Alberto , Cao Xiangyu
Published: February 2023

Brownian particles that are replicated and annihilated at equal rate have strongly correlated positions, forming a few compact clusters separated by large gaps. We characterize the distribution of the particles at a given time, using a definition of clusters in terms of a coarse-graining length recently introduced by some of us. We show that, in a non-extinct realization, the average number of clusters grows as

∼

t

D

f

/

2

where

D

f

≈
0.22

is the Hausdorff dimension of the boundary of the super-Brownian motion (SBM), found by Mueller, Mytnik, and Perkins. We also compute the distribution of gaps between consecutive particles. We find two regimes separated by the characteristic length scale

ℓ
=

D

/

β

where D is the diffusion constant and β the branching rate. The average number of gaps greater than g decays as

∼

g

D

f

−
2

for

g
≪
ℓ

and

∼

g

−

D

f

for

g
≫
ℓ

. Finally, conditioned on the number of particles n, the above distributions are valid for

g
≪

n

; the average number of gaps greater than

g
≫

n

is much less than one, and decays as

≃

4
(
g

/

n

)

−
2

, in agreement with the universal gap distribution predicted by Ramola, Majumdar, and Schehr. Our results interpolate between a dense SBM regime and a large-gap regime, unifying two previously independent approaches.
Preliminary study on marine associated bacteria-marine invertebrate relationship: observation of valinomycin from Streptomyces in Stichopus vastus
Authors: Wibowo J T , Kellerman M Y , Schupp P J
Published: February 2023

We isolated valinomycin and its analogs from Streptomyces sp. SV 21 obtained from sea cucumber Stichopus vastus. Besides its antibacterial capacity, past studies on valinomycin also showed a broad-spectrum antiviral activity. From an ecological perspective, valinomycin showed interesting bioactivities in host-microbes relationships, such as protection against pathogenic fungi in leafcutter ant Acromymex echinatior and suppression of large patch disease in zoysia grass Zoysia japonica. However, valinomycin’s ecological role remains unclear in the marine environment. For that reason, we observed a trace of valinomycin in S. vastus. We extracted S.vastus with MeOH. Unlike the extract of Streptomyces sp. SV 21, the extract of S. vastus showed no activity when tested against environmental bacteria using disc-diffusion assays. The crude extract was fractionated with n-hexane, DCM, BuOH, and water. The samples were then analyzed with UHPLC-MS. The MS spectra showed valinomycin was not detected in the MeOH extract. However, some mass fragments of valinomycin were observed in the mass spectra of the DCM and BuOH fractions. These results could pave the way for further studies on the observation of valinomycin in the parts of sea cucumber and/or its habitat and valinomycin’s role for marine organisms, especially sea cucumbers.
The effect of phytoplankton abundance on zooplankton behavior during the day and night in the waters of the northern Peninsula of the Banyuasin Coast, South Sumatra
Authors: Febrianti A A P , Fauziyah  , Agustriani F , Ningsih E N , Manik H M , Wijopriono  , Supriyadi F
Published: February 2023

Plankton has an important role and can be used as a bioindicator of water conditions. The abundance of phytoplankton and the behavior of zooplankton are interrelated, namely the interaction of prey and predators. Phytoplankton form community structures and zooplankton community structures give rise to feeding strategies as predators. The purpose was to observe the behavior of zooplankton at the time of observation based on the level of abundance of phytoplankton. This research was conducted in October 2020 in the waters of the northern peninsula of the Banyuasin coast, South Sumatra. Sampling of plankton using a horizontally pulled bongonet for 5 minutes. The results showed that the abundance of phytoplankton contributed indirectly to the behavior of zooplankton, differences in time and environmental conditions such as tides and temperature also contributed. The highest abundance of phytoplankton was found at station 4 at night with an abundance of 71553 cells/m3, while the highest abundance of zooplankton was at station 5 at night 1332 ind/m3. The distribution of the movement of zooplankton in the study waters is below during the day and begins to increase in abundance at night, this is indicated by the behavior of zooplankton looking for prey at night with the main target being phytoplankton.
Relationship analysis of Scalloped Hammerhead (Sphyrna lewini) from West Aceh Waters using molecular genetics approach
Authors: Bahri S , Hikmah N , Fadli N
Published: February 2023

Hammerhead sharks are particularly vulnerable to fishing because of their slow growth rate and reproductive constraints. This type of sharks needs special attention due to its conservation status. This research was aimed to describe the relationships of the hammerhead sharks from West Aceh waters with the hammerhead sharks from other places. Samples of the shark were collected from Ujong Baroh Fish Port, West Aceh. The samples were analysed at the Laboratory of Department of Marine Science and Fisheries, Syiah Kuala University. The laboratory activity was started with extraction of DNA enhanced by Polymerase Chain Reaction method and visualized by an electrolytical. Analysis using BLAST showed that the first sample obtained 94%-95% cover query value and produced a 683 base pair length while the second sample obtained 98% per sample for a cover query value and produced a 658 base pair length. The average nucleotide values of the hammerhead shark were T=32.8, C=26.6, A=25.7 and G=14.9. The phylogenetic tree shows that the hammerhead sharks from the study area were more similar to the hammerhead sharks from Australia and Malaysia. Overall, based on the nucleotide composition, phylogenetic tree and genetic distance, the hammerhead sharks from the study area are unique compared to the populations from the other places.
Is the variability of butterflyfish species domination driven by its habitat conditions?
Authors: Faricha A , Rejeki H A , Munasik
Published: February 2023

The coral conditions contribute to the abundance and species composition of butterflyfish. This study investigates the relationship between its habitat conditions and dominance of butterflyfish in western Indonesia. Data were collected using UVC in 78 sites during 2015, 2016, and 2018 that are grouped into 2 groups. The results show group A has a lower number of species (2 - 6) but the density is high, instead, group B is 9-20 species but has a low density. Species dominant and their relations with benthic substrate were Chaetodon octofasciatus (7.2%) in group A, and group B Heniochus pleurotaenia and Chaetodon triangulum (21%). The differences in species domination might also be affected by habitat conditions, such as the period of the highest sea surface temperature. The group had different environmental conditions, which group A might be influenced by the Karimata strait and Indian Ocean west Sumatera in group B. Those 4 species have relation to SST include F. flavissimus.
Characteristics of coral reef fisheries in the Wakatobi islands
Authors: Prihatiningsih  , Taufik M , Baihaqi  , Yusuf H N , Fauzi M , Hufiadi  , Chodrijah U , Panggabean A S , Pane A R P , Hartati S T
Published: February 2023

Wakatobi National Park has a diverse fish population, and its conservation potential for reef fish resources is quite large. As a result, to be sustainable, the exploitation of these resources must be properly managed. This study aims to look into the characteristics of reef fish fisheries, such as species composition, catch, fishing ground, and fish length. The outcomes are hoped to be beneficial in monitoring the management of the resources. This research was conducted in April-November 2018 in Wakatobi, Indonesia. Analytical methods process the data. The results showed that gold spotted rabbitfish (Siganus punctatus), parrotfish (Hipposcarus longiceps), emperor (Lethrinus lentjan), grouper (Epinephelus sp), and trevallies (Caranx sp) dominated the total catch from muroami, speargun, and hand line. Muroami boats have a higher average CPUE (212 kg/trip/month) than speargun (29.0 kg/trip/month) and handlines (13.0 kg/trip/ship). Some of the reef fish caught in Wakatobi National Park is small and immature. Muroami net, speargun, and handline fishing are mostly done in the southern part of the Wakatobi National Park area, around Binongko Island. One of the management actions undertaken by Wakatobi fishermen is fishing inside the management zone that has been established, namely the local use zone.
Fishing impact of blue swimming crab (Portunus pelagicus) fishery on target in Lamongan Water, Northern Coast of Eastern Java Province
Authors: Nabila A N , Taurusman A A , Wiryawan B , Riyanto M
Published: February 2023

Blue swimming crab (Portunus pelagicus) is a high-value export commodity of fisheries to the international market. Thus, it promotes overfishing, reducing target stocks, and ecological impact on non-target biota. Fishers in Lamongan Regency use traps, trammel nets, and mini trawl (arad) to target the crabs. The fishing gears have different levels of selectivity. This study aims to evaluate the impact of crab fishing on target (P. pelagicus), particularly in the study area. The samples of blue swimming crab (BSC) were collected using the quota sampling method. The parameters of the crab catch (Portunus pelagicus) collected included carapace width, weight, sex, and gonad maturity stage (GMS). 1424 fishing vessels and 3598 fishers targeted the BSC in the Lamongan water. The result of this study showed that 93% of BSC catch was higher than the legal size from traps, 66% (arad), 89 % (trammel nets). The growth parameter of L∞ = 156.95 mm (for female) and L∞ = 182.22 mm (male), while K = 1.4 per year (for female) and K = 1.4 per year (male). The relationship between carapace width and weight of the male and female crabs was positive allometric growth. The LB-SPR parameter value was 23% which indicated that the crab resource stock in Lamongan waters was a ‘fully-moderately’ status, while the selectivity level indicated an ‘over-exploitation’ base on the E value = 0.69 (for female crab) and E = 0.72 (for male). This study proposes urgently reducing the fishing effort targeting BSC, particularly by the mini trawl (arad) and implementing a rebuilding stock program for the BSC.
Effect of dietary honey supplementation on weight growth performance of Asian seabass (Lates calcarifer)
Authors: Muzahar  , Viruly L , Muslim A
Published: February 2023

This study aimed to identify the effect of local bee (Apis dorsata) honey as a feed additive on the growth performance of Asian seabass (Lates calcarifer). The honey was supplemented at 1%, 2%, and 3% per kg diet. The test fish were reared for 35 days in a net placed in a floating-net cage (KJA). The results showed that the dietary honey supplementation affected the absolute weight and specific growth rate (p<0.05). The supplementation of 3% honey per kg diet obtained the highest growth performance compared to other treatments with the weight growth at 42.43 ± 12.78 g, specific growth rate at 1.21 ± 0.37 g/day and survival rate at 100%. The water quality parameters in the rearing tank of test fish were eligible based on the Indonesian National Standard (SNI) of 01-6493.1-2000 about water quality for Asian seabass grow-out rearing.
Estimating ecological and production carrying capacity for lobster farming based on organic carbon deposition in the mariculture zone
Authors: Thesiana L , Albasri H , Pratama I , Hanintyo R , Rahmania R , Susilo E , Suniada K I , Puspasari R , Istiyarini N , Setiati N A
Published: February 2023

Lobster farming produces higher organic carbon footprints; thus, a carrying capacity model must be developed specifically to address the issue. This study aimed to develop a carrying capacity for lobster farming based on a carbon deposition model. Bay and open waters (worst and best scenarios) carbon deposition models were developed using DEPOMOD. Two net cage configurations were used in each model. Current velocity, farming practices, and coastal geodatabases of seven provinces were analysed. The maximum carbon deposition in the bay was higher (1.67 kgC/m2/day) than in the coastal area (0.55 kgC/m2/day) for the single net cage configuration. Similarly, the bay’s four net cages produced a higher carbon deposition (4.11 C kg/m2/day) than the coastal net cages (0.88 kgC/m2/day). The bay has a smaller carbon footprint for both net cage configurations (68.98-140.12 m) compared to the coastal waters’ net cages (100.76-198.19 m). Based on the carbon deposition models, it is estimated that the assessed 598 Indonesia’s mariculture zones (total area of 1.47 million ha) could support 92,904 net cages (200 frames/net cage) capable of producing lobster of 557,429 tonnes/year. The proposed models could be used to replace the generic carrying capacity for lobster farming in Indonesia’s mariculture zones
Fish and shrimp hydrolysate as additives in lobster feed formulation: effect on growth, survival, feed consumption of spiny lobster (Panulirus homarus)
Authors: Astuti N W W , Sudewi  , Giri N A , Fahrudin  , Asih Y N , Slamet B
Published: February 2023

Artificial feed formulation has been developed to minimize trash fish use in spiny lobster (Panulirus homarus) culture. However, lobster growth was higher when they were fed fresh diets. Low feed intake was considered a problem in artificial feed development. This study aimed to evaluate fish and shrimp hydrolysate as attractants in lobster feed formulation. This research conducted three treatments, i.e., benchmark feed as control (A), feed with 3% fish hydrolysate (B), and feed with 3% shrimp hydrolysate (C). Lobsters with an initial carapace length of 6.12 cm and initial weight of 97.6 g were allocated into fiberglass tanks (2×2×1 m3) with a stocking density of 40 lobsters/tank. Lobsters were fed with moisture pellets with 24%-25% moisture content three times daily. The lobster’s weight and carapace length were measured every four weeks. Twelve weeks of observation showed no significant effects of treatments (p<0.05) on growth, feed consumption, lobster survival, and molt frequency. The final weight of the lobster ranged from 115.81 g to 116.10 g. The final carapace length was around 6.52 cm - 6.55 cm, the specific growth rate was around 0.20 %/day, and feed consumption ranged from 250 g/day – 267 g/day. While the survival rate ranged from 60.83% to 72.50%, and molt frequency was around 21 - 25 times during observation.
Bombay duck (Harpodon nehereus) natural formaldehyde levels and changes during frozen storage
Authors: Ariyani F , Barokah G R , Wibowo S
Published: February 2023

Demersal fish, including the Bombay duck (Harpodon nehereus), have relatively high levels of TMAO and hence have the potential for high natural formaldehyde content. This study aimed to determine the natural formaldehyde content of bombay duck and the pattern of the change during frozen storage. Approximately 15 kg bombay duck of 38 – 45g each caught by one-day fishing in Juwata Waters, Tarakan, North Kalimantan Indonesia, was transported in ice to the Laboratory of Marine Biotechnology, Research Center for Marine and Fisheries Product Processing and Biotechnology, Jakarta. Upon arrival, they were split into three groups as replicates and stored frozen for five months. Every month, the levels of formaldehyde, TVB, and sensory properties were monitored, and proximate analysis was performed before storage. The results showed that natural formaldehyde was detected in Bombay duck flesh before storage at a relatively high level of 12.58 + 0.35 ppm, increased to 17.3 ppm after one month of storage, and then decreased afterward. In contrast, TVB levels were low, 12.66 + 2, 54 mg N% before storage, then increased during storage. Based on sensory evaluation, all attributes of the bombay duck were deemed in good condition, with scores ranging from 7-8, except for the eyes, which received a score of less than 6.
Characteristics of crab shells and green mussel shells as potential chitosan material from Karangantu, Banten, Indonesia
Authors: Pratama G , Munandar A , Surilayani D , Rizky J A , Hasanah A N , Haryati S , Meata B A , Nuryadin D F E , Aditia R P
Published: February 2023

Shells are a waste of crab (Portunus pelagicus) and green mussels (Perna viridis) waste in Karangantu. That is a problem for the environment with a large number. One solution is to use it as a raw material for chitosan. This study aims to see the potential of crab shells and green mussel shells as well as raw materials for chitosan biomaterials. This research used shell waste of P. pelagicus and P. viridis (3 replications). The stages of the method of this research include the preparation of raw materials, manufacture of chitosan, and analysis product. Parameters measured in this study include yield, moisture, ash, degree of deacetylation, and viscosity. The results showed that the yield, ash, and viscosity of green mussels shells were higher than that of crab shells, but the moisture and degree of deacetylation were lower. These results indicate that crab shells are better than clam shells, although the yield is lower as a potential for making chitosan from waste in Karangantu.
The role of dryoprotectants on the quality of surimi powder of red tilapia
Authors: Ramadhan W , Santoso J , Trilaksani W , Rieuwpassa F J
Published: February 2023

Since the commercial wet surimi should be stored at frozen temperature, thus requires space and high energy consumption. Interestingly, surimi in dried powder form reveals the new prospect of relieving those drawbacks of wet surimi. However, the drying process indicates fast hydration that may affect water and protein content loss, causing a reduction of gelling capacity. To date, this study aimed to determine the right type and concentration of cryoprotectant to protect the quality of red tilapia surimi powder during its freeze-drying process. The inclusion of different cryoprotectants was obtained in the production of surimi powder, namely surimi powder with cryoprotectant blend I (4% sucrose, 4% sorbitol, 0.3% polyphosphate) (DB4), cryoprotectant blend II (8% sucrose, 8% sorbitol, 0.5% polyphosphate) (DB 8), trehalose 2 (TH2), 4 (TH4), 6 (TH6) and 8% (TH8) and as well as surimi powder without cryoprotectant as the control (WD). The generated surimi powder with various cryoprotectant types was evaluated for the whiteness degree, myofibril content, gel strength, emulsion capacity, and foaming capacity. The generated surimi powder with TH8 showed the most acceptable result with myofibril 1.098±0.103 mg/mL, gel strength 1156.65±41.32 gf/cm2, whiteness 90.35%, emulsion capacity 79.1% and foaming capacity 39.12%.
The role of microorganisms in solid biofertilizer production
Authors: Basmal J , Kusumawati R , Nurhayati
Published: February 2023

Trials of making organic fertilizer using seaweed, fish silage, molasses, and a consortium of microbes were carried out. This study aimed to determine the activity of Bacillus subtilis, Pseudomonas florescent, and Trichoderma sp to produce micro and macro nutrients, humic acid, water content, and growth hormone. The organic fertilizer formula consisted of 26.6% sargassum flour, 16% fish silage, 1.8% molasses, 2.4% K. alvarezii paste; and 53.2% sargassum paste. The treatments consisted of formulated without adding microbial consortium (SK) and with adding microbial consortium (SM) as much as 10% volume per weight (v/w), then fermented for 10 days at room temperature. The balance values of growth hormone auxin (IAA), gibberellin (GA3) and cytokinins in SM treatment were the best measured at 181 ppm, 73 ppm, and 120 ppm, respectively.