bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation on the interaction between mode-2 internal solitary wave and horizontal transverse cylinder
Authors: Wang Shaodong , Du Hui , Wei Gang , Peng Pai , Xuan Pu , Wang Guanjing
Published: August 2023

The experimental study on the interaction between a mode-2 internal solitary wave (ISW) and a horizontal transverse cylinder has been carried out in a large gravity-stratified fluid flume. One kind of making-wave method of “rotating-blade-gate” is proposed to achieve the experimental simulation of the standard mode-2 ISW in the laboratory flume. The conductivity probe array and particle image velocimetry are used to measure the mode-2 ISW and its wave-flow structure of the interaction with the horizontal transverse cylinder, and the micro-amplitude force sensor is used to measure the forces of the mode-2 ISW on the cylinder model. It is shown that the mode-2 ISW geometric structure is characterized by a convex and concave oval wave envelope shape and the counterclockwise and clockwise circulations are formed in its convex and concave domains, respectively. The resulting pair of upper and lower antisymmetric circulations moves forward together, which causes a horizontal strong flow at the symmetric center of the wave envelope consistent with the wave propagation direction. The horizontal transverse cylinder is subjected to the combined action of horizontal flow, vertical flow, and density change induced by the mode-2 ISW, in which the horizontal strong flow, induced flow separation, and vortex structure located at the symmetric center of the wave envelope are the signature features that are different from other positions. The theoretical analysis model of the forces exerted by the mode-2 ISW on a horizontal transverse cylinder is established. The spatial distribution characteristic of the force exerted by the mode-2 ISW on a horizontal cylinder is obtained, and the essential reason for the maximum horizontal and vertical loads on the cylinder is revealed. The horizontal maximum load corresponds to the inhomogeneous change of the horizontal velocity along the depth, and the vertical maximum load depends on the maximum density change along the depth, of which variation trend corresponds to the linear change of wave amplitudes.
A temperature-tunable chirality-selective meta-absorber for electromagnetic encrypted imaging
Authors: Xiong Ting-Hui , Li Wei , Yi Qian-Yi , Su Pei-Hao , Peng Yu-Xiang , Liu Yuan-Yuan , Wang Kai-Jun , Zhang Xin-Min , Li Jian-Bo , Liu Jian-Qiang , He Meng-Dong
Published: August 2023

Metamaterial-based technologies offer opportunities to realize spin-selective encryption platforms for key encoding, yet the flexibility and controllability of encrypted imaging are not satisfactory well enough. In this paper, we propose a temperature tunable chirality-selective meta-absorber based on the thermal phase change material of vanadium dioxide (VO2). The meta-absorber has the functionality of spin-selective absorption in high temperature, which enables perfect absorption at resonant frequency for one spin state of light, and a little loss for the other, resulting in a significant absorption circular dichroism (CD). The CD can be actively manipulated by ambient temperature (i.e., conductivity of VO2). Importantly, spin-encoded near-field imaging of letters and quick response codes are achieved using the CD effect of VO2 resonators and their enantiomers. The image contrast decreases with the reduction of ambient temperature and disappears at room temperature, which enables thermal-control electromagnetic encrypted imaging and hiding. This work provides a route for the development of tunable chiroptical systems, information encryption technologies, and temperature-control imaging devices.
Large-amplitude oscillatory shear flow from general rigid bead-rod theory
Authors: Pak Myong Chol , Giacomin A. J. , Kanso M. A. , Pak Hak Chol
Published: August 2023

Oscillatory shear flow, performed at small-amplitude, interrogates polymeric liquids in their equilibrium states. The fluid responds in sinusoidal shear stress waves whose amplitude and phase lead depend on the dimensionless frequency (called the Deborah number). By contrast, this same flow field, performed at large-amplitude, probes departures from the equilibrium state, and the fluid responds with shear stress in the form of a Fourier series, whose component amplitudes and phase leads depend on both the dimensionless frequency (called the Deborah number) and the dimensionless shear rate amplitude (called the Weissenberg number). The physics of these departures from equilibrium in an oscillatory shear flow may be explained by (i) chain disentanglement or (ii) motion along the polymer chain axes (called reptation) or (iii) macromolecular orientation. Of these radically different and yet otherwise equally effective approaches, only (iii) allows the macromolecular structure to be varied arbitrary so that the effect of molecular architecture on the rheology can be explored. Though much has been written about a large-amplitude oscillatory shear flow, we understand little about the role of molecular structure on the measured behaviors, and this has limited its usefulness. In this work, we explain the higher harmonics of both the shear stress (first and third), the first normal stress differences (zeroth, second, and fourth), and the second normal stress differences (zeroth and second) arriving at analytical expressions for all three. These expressions, written in dimensionless form, express the dimensionless rheological responses in large-amplitude oscillatory shear flow in terms of the ratio of the two principal macromolecular moments of inertia. To get these expressions, we derive the first five terms of the orientation distribution function, by solving the general diffusion equation in Euler coordinates. We then integrate in phase space with this orientation result to arrive at our expression for the first seven terms of the polymer contribution to the extra stress tensor. From this tensor, we next write down the Fourier coefficients for the shear stress responses, and the normal stress difference responses, in large-amplitude oscillatory shear flow for a suspension of macromolecules sculpted from a rigid bead-rod structure of any arbitrary axisymmetric shape.
Brute-force nucleation rates of hard spheres compared with rare-event methods and classical nucleation theory
Authors: Gispen Willem , Dijkstra Marjolein
Published: August 2023

We determine nucleation rates of hard spheres using brute-force molecular dynamics simulations. We overcome nucleation barriers of up to 28 kBT, leading to a rigorous test of nucleation rates obtained from rare-event methods and classical nucleation theory. Our brute-force nucleation rates show excellent agreement with umbrella sampling simulations by Filion et al. [J. Chem. Phys. 133, 244115 (2010)] and seeding simulations by Espinosa et al. [J. Chem. Phys. 144, 034501 (2016)].
Utilizing 2D materials in liquid crystal–based electro-optic devices: A perspective
Authors: Basu Rajratan
Published: August 2023

The alignment agent plays a crucial role in the electro-optical characteristics of an electro-optic liquid crystal (LC) device. Conventionally, rubbed polyimide (PI) layers have been utilized as alignment agents in LC devices. However, these organic PI layers are sensitive to UV rays and high temperatures. The rubbing procedure involved in preparing PI layers also introduces drawbacks, including non-uniform brightness due to uneven rubbing mechanisms and the presence of residual fiber dust. In our recent research, we demonstrated that various hexagonal 2D (inorganic) materials, such as monolayer graphene, monolayer tungsten diselenide (WSe2), and monolayer hexagonal boron nitride (h-BN) nanosheets, can effectively serve as planar-alignment agents in electro-optic LC devices. In this Perspective, we review the rubbing-free LC alignment process, which relies on the coherent overlay of the benzene rings of LC molecules on the hexagonal lattice structure of 2D materials. We review our recent results on LC devices utilizing 2D materials as alignment agents, highlighting their potential advantages. Furthermore, we discuss the challenges associated with this research field. Finally, we provide our perspectives on the future directions and opportunities for advancing this area of study, aiming to overcome challenges and extend the benefits of employing 2D materials as planar-alignment agents in electro-optic LC devices.
Pressure-induced phase transitions and metallization in layered SnSe
Authors: Luo Yuhua , Shi Yuyang , Wu Min , Wu Ye , Wang Kai , Tu Bingtian , Huang Haijun
Published: August 2023

The group IV–VI monochalcogenides have attracted widespread attention because of their diverse physical properties and promising applications in electronics and optoelectronics. As a typical IV–VI semiconductor, SnSe displays ultra-low thermal conductivity and excellent thermoelectric properties, which deeply depends on its layered structure. The layered crystal structure and associated physical properties are sensitive to external pressure. Here, we have systematically investigated the structural behaviors and optical and electrical properties of layered SnSe under high pressure. The SnSe transforms from Pnma phase to Cmcm phase above 10 GPa, and a CsCl-type structure with a space group of Pm3¯m emerges around 30 GPa and coexists with Cmcm phase up to 42.5 GPa. The optical bandgap of SnSe shows gradual narrowing with increasing pressure, indicating gradual metallization of SnSe under compression. The pressure-induced metallization of SnSe is verified by electric transport experiments. The initial semiconducting SnSe transforms to a metallic state with increasing pressure up to 9.8 GPa. Both phase transitions and optical and electrical properties of SnSe at high pressure are reversible after releasing pressure. Our study provides a modulation strategy of crystal structures and physical properties for the group IV–VI monochalcogenides to broaden their applications in thermoelectric and optoelectronic fields.
Leakage function in magnetic domain wall based artificial neuron using stray field
Authors: Mah Wai Lum William , Chan Jian Peng , K. R. Ganesh , Naik V. B. , Piramanayagam S. N.
Published: August 2023

Recently, brain-inspired neuromorphic computing (NC) has been gaining traction as it is expected to be more power efficient and a more suitable platform for artificial intelligence. Artificial neurons and synapses are the main components of the NC architecture, and there have been many studies on artificial synapses. Experimental studies on artificial neurons that should exhibit the leaky integrate-and-fire properties are lacking due to the challenges in fabricating such a device. In this work, we have fabricated domain wall based devices consisting of (Co/Pt)n free and hard layers without interlayer exchange coupling, whereby the stray field from the hard layer triggers the automatic leakage function in the free layer. In addition, devices of smaller width were able to fully reset, showing the potential to scale down to smaller sizes. This experimental proof of concept provided evidence that the proposed neuron design has potential applications in NC. Further studies were performed via micromagnetic simulations to understand the role of the width of the device, thickness, and saturation magnetization of the hard layer.
Evaluation of a dietary blend of essential oils and polyphenols on methane emission by ewes
Authors: Atzori A. S. , Porcu M. A. , Fulghesu F. , Ledda A. , Correddu F.
Published: August 2023

Context Decreasing enteric methane emissions from small ruminants is important because methane is a greenhouse gas and a major contributor to global warming. Aim The objective of this work was to test the effect of a dietary premix consisting of a blend of essential oils, bioflavonoids and chestnut tannins (EOP, essential oils and polyphenols) on methane emission from dry non-pregnant ewes. Methods Twenty-four dry Sarda ewes were allocated to two homogenous groups: control and treatment groups. Both were fed with a total mixed ration, and the treatment group was supplemented with 1 g/day.ewe of EOP blend. Each animal followed a 20-day adaptation period before methane emission measurements. Methane emissions were measured using a ventilated hood system equipped with a digital gas analyser. Key results The addition of a dietary EOP blend to the total mixed ration did not affect feed intake and nutrient digestibility. Ewes that received the EOP blend had a 13% lower methane yield than ewes that received the control diet (22.4 vs 25.5 g of CH4 per kg of dry matter intake; P < 0.05, respectively). The EOP blend had no impact on daily methane emission when calculated as g CH4/ewe or g CH4/kg bodyweight. Conclusions The EOP blend at a daily dose of 1 g/day.ewe decreased methane yield under the experimental conditions described in this work. Implications Feeding an EOP dietary blend to ewes can decrease methane emission. These results were obtained in vivo with typical farm conditions, suggesting that a similar response may occur in field conditions.
A law of data separation in deep learning
Authors: He Hangfeng , Su Weijie J.
Published: August 2023

While deep learning has enabled significant advances in many areas of science, its black-box nature hinders architecture design for future artificial intelligence applications and interpretation for high-stakes decision-makings. We addressed this issue by studying the fundamental question of how deep neural networks process data in the intermediate layers. Our finding is a simple and quantitative law that governs how deep neural networks separate data according to class membership throughout all layers for classification. This law shows that each layer improves data separation at a constant geometric rate, and its emergence is observed in a collection of network architectures and datasets during training. This law offers practical guidelines for designing architectures, improving model robustness and out-of-sample performance, as well as interpreting the predictions.
A spin-mechanical quantum chip for exploring exotic interactions
Authors: Wu Longhao , Lin Shaochun , Kong Xi , Wang Mengqi , Zhou Jingwei , Duan Chang-Kui , Huang Pu , Zhang Liang , Du Jiangfeng
Published: August 2023

How to illuminate dark matter has become the foremost open question in fundamental science nowadays, which is of great significance in understanding the laws of nature. Exploring exotic interactions beyond the standard model is one of the essential approaches to searching for dark matter particles. Although it has been explored in a variety of lab-scale and tabletop-scale setups over the past years, no such interactions have been observed, and improving the sensitivity significantly becomes of paramount importance, but challenging. Here, we formulate the conception of a spin-mechanical quantum chip compatible with scalable on-chip detectors. Utilizing the prototype chip realized by the integration of a mechanical resonator and a diamond with single nitrogen vacancy at the microscale, the constraints of spin-velocity-dependent interactions have been improved by two orders of magnitude, where there is no evidence for new bosons in the force range below 100 nm, i.e., in the rest-mass window of 2–10 electronvolts. Based on the proof-of-principle experiment, this promising chip can be scaled up to meet the requirements of searching for exotic interactions at preeminent sensitivity. Low-cost and high-yield chip-scale setups will accelerate the process of dark matter exploration, providing a path toward on-chip fundamental physics experiments.
Quantum electrodynamics of time-varying gratings
Authors: Horsley Simon A. R. , Pendry John B.
Published: August 2023

Gratings which are in apparent motion reveal some startling properties for classical radiation, especially for luminal gratings traveling at or around the speed of light. We show here that their quantum properties are even more remarkable, their effective refractive index modeling the Schwarzschild singularity which as we show generates spontaneous Hawking radiation in correlated photon pairs. Subjected to external radiation, luminal gratings provoke stimulated emission of photon pairs which we propose as a possible means of observing Hawking radiation in the laboratory.
The Puss in Boots effect
Authors: Forman Jemma , Brown Louise , Root-Gutteridge Holly , Hole Graham , Lesch Raffaela , Pisanski Katarzyna , Reby David
Published: August 2023

Pet-directed speech (PDS) is often produced by humans when
addressing dogs. Similar to infant-directed speech, PDS is marked by a
relatively higher and more modulated fundamental frequency
(f
0) than is adult-directed speech. We tested
the prediction that increasing eye size in dogs, one facial feature of neoteny
(juvenilisation), would elicit exaggerated prosodic qualities or pet-directed
speech. We experimentally manipulated eye size in photographs of twelve dog
breeds by −15%, +15% and +30%. We first showed that dogs with larger eyes were
indeed perceived as younger. We then recorded men and women speaking towards
these photographs, who also rated these images for cuteness. Linear
mixed-effects models demonstrated that increasing eye size by 15% significantly
increased pitch range (f
0 range) and variability
(f
0CV) among women only. Cuteness ratings did
not vary with eye size, due to a possible ceiling effect across eye sizes. Our
results offer preliminary evidence that large eyes can elicit pet-directed
speech and suggest that PDS may be modulated by perceived juvenility rather than
cuteness. We discuss these findings in the context of inter-species vocal
communication.
Grapheme–phoneme correspondence learning in parrots
Authors: Cunha Jennifer M. , Hirskyj-Douglas Ilyena , Kleinberger Rèbecca , Clubb Susan , Perry Lynn K.
Published: August 2023

Symbolic representation acquisition is the complex cognitive process consisting of learning to use a symbol to
stand for something else. A variety of non-human animals can engage in symbolic representation learning. One particularly complex
form of symbol representation is the associations between orthographic symbols and speech sounds, known as grapheme–phoneme
correspondence. To date, there has been little evidence that animals can learn this form of symbolic representation. Here, we
evaluated whether an Umbrella cockatoo (Cacatua alba) can learn letter-speech correspondence using English words.
The bird-participant was trained with phonics instruction and then tested on pairs of index cards while the experimenter spoke the
word. The words were unknown to the bird and the experimenter was blinded to the correct card position. The cockatoo’s accuracy
(M = 71%) was statistically significant. Further, we found a strong correlation between the bird’s
word-identification success and the number of overlapping letters between words, where the more overlapping letters between words,
the more likely the cockatoo answered incorrectly. Our results strongly suggest that parrots may have the ability to learn
grapheme–phoneme correspondences.
The abscission checkpoint senses chromatin bridges through Top2α recruitment to DNA knots
Authors: Petsalaki Eleni , Balafouti Sofia , Kyriazi Athina A. , Zachos George
Published: August 2023

In response to chromatin bridges, the abscission checkpoint delays completion of cytokinesis to prevent chromosome breakage or tetraploidization. Here, we show that spontaneous or replication stress-induced chromatin bridges exhibit “knots” of catenated and overtwisted DNA next to the midbody. Topoisomerase IIα (Top2α) forms abortive Top2–DNA cleavage complexes (Top2ccs) on DNA knots; furthermore, impaired Top2α–DNA cleavage activity correlates with chromatin bridge breakage in cytokinesis. Proteasomal degradation of Top2ccs is required for Rad17 localization to Top2-generated double-strand DNA ends on DNA knots; in turn, Rad17 promotes local recruitment of the MRN complex and downstream ATM-Chk2-INCENP signaling to delay abscission and prevent chromatin breakage. In contrast, dicentric chromosomes that do not exhibit knotted DNA fail to activate the abscission checkpoint in human cells. These findings are the first to describe a mechanism by which the abscission checkpoint detects chromatin bridges, through generation of abortive Top2ccs on DNA knots, to preserve genome integrity.
Manipulating Skyrmion Motion on a Nanotrack with Varied Material Parameters and Tilted Spin Currents
Authors: Luo 罗 Jia 佳 , Guo Jia-Hao , Hou 侯 Yun-He 云鹤 , Wang 王 Jun-Lin 君林 , Xu 徐 Yong-Bing 永兵 , Zhou 周 Yan 艳 , Pong Philip Wing Tat , Zhao 赵 Guo-Ping 国平
Published: August 2023

Magnetic skyrmions are topological quasiparticles with nanoscale size and high mobility, which have potential applications in information storage and spintronic devices. The manipulation of skyrmion’s dynamics in the track is an important topic due to the skyrmion Hall effect, which can deviate the skyrmions from the preferred direction. We propose a new model based on the ferromagnetic skyrmion, where the skyrmion velocity can be well controlled by adjusting the direction of the current. Using this design, we can avoid the annihilation of the skyrmion induced by the skyrmion Hall effect, which is confirmed by our micromagnetic simulation based on Mumax3. In the meantime, we increase the average velocity of the skyrmion by varying the intrinsic material parameters in the track, where the simulations agree well with our analytical results based on the Thiele equation. Finally, we give a phase diagram of the output of the skyrmion in the T-type track, which provides some practical ways for design of logic gates by manipulating crystalline anisotropy through the electrical control.
Topological resonators based on hexagonal-star valley photonic crystals
Authors: Wan 万 Xin 鑫 , Peng 彭 Chenyang 晨阳 , Li 李 Gang 港 , Yang 杨 Junhao 俊豪 , Qi 齐 Xinyuan 新元
Published: August 2023

In valley photonic crystals, topological edge states can be gained by breaking the spatial inversion symmetry without breaking time-reversal symmetry or creating pseudo-spin structures, making highly unidirectional light transmission easy to achieve. This paper presents a novel physical model of a hexagonal-star valley photonic crystal. Simulations based on the finite element method (FEM) are performed to investigate the propagation of TM polarized mode and its application to ring resonators. The results show that such a topologically triangular ring resonator exhibits an optimum quality factor Q of about 1.25 × 104, and Q has a maximum value for both frequency and the cavity length L. Our findings are expected to have significant implications for developing topological lasers and wavelength division multiplexers.
Preliminary study of fungi from mangrove sediments as a bioremediation agent of lead (Pb) heavy metal
Authors: Millatia Z , Sabdaningsih A , Ayuningrum D , Jati O E , Muskananfola M R
Published: August 2023

The mangrove ecosystem in Tapak Village is one of the coastal areas in Tugu District, Semarang, Central Java and close to the industrial area. This mangrove ecosystem presumed to be contaminated by heavy metals. This study aims to analysis of lead heavy metal in Tapak, isolate fungi from mangrove sediments, and identify the potential fungus according to molecular approach. The sampling method used a purposive random sampling method with 4 sampling points. The isolation of fungi was carried out using the dilution method and then cultured on the general Potato Dextrose Agar (PDA) media. The purified isolates were tested its ability as a bioremediation agent of lead heavy metal (Pb) and were identified molecularly using ITS1 and ITS4 as universal primers. The results of the analysis of the Pb content in the sediment samples using the Atomic Absorption Spectrophotometer (AAS) ranged from 59.07-76.76mg/Kg, where these results exceeded the CCME (Canadian Council of Ministers of the Environment) quality standards, 2001, with Pb standards of 35mg/Kg. Based on the screening of fungal isolates on media supplemented with (Pb) of 70 ppm, a total 18 isolates were purified. There were 9 isolates with the fastest growth in observations for 7 days. One of the 9 fastest-growing isolates, MT.1.E, was identified molecularly using Internal Transcribe Spacer (ITS) region and the homology was closely related to Aspergillus fumigatus which has a 100% similarity. According to this study, fungi can be proposed as a bioremediation agent.
Morfometric Character of Longtail Tuna (Thunnus Tonggol)
Authors: Hidayat Thomas , Boer Mennofatria , Kamal M Mukhlis , Zairion  , Suman Ali
Published: August 2023

Longtail tuna is a pelagic fish that has a wide distribution from the Java Sea to the Natuna Sea or the South China Sea. This study aims to identified the character of the population and determine differences in population/stock of longtail tuna among stock in the Java Sea and the Natuna Sea. Sampling was carried out from May 2018 to April 2019, in Pekalongan representing the Java Sea, Pemangkat representing the west Natuna Sea and Tanjung Pinang representing the east Natuna Sea. The morphometric measurement consists of 20 characters, morphometric data is standardized by dividing all the morphometric characters by the standard length (SL). Principal components and discriminant functions analysis was employed to analyze morphometric variables to obtain distinguishing characters and stock identification. Discriminant Analysis to see the components of intra and inter-population sharing was carried out using SPPS ver.16 software. The results of Principal components analysis (PCA) found there are two distinguishing morphometric characters, namely: pelvic fin length (PeL) and anal fin length (PAF) characters. Canonical discriminant analysis found two subpopulation longtail tuna, which is one sub population Java Sea and west Natuna Sea, the other is east Natuna Sea sub population.
Potential Absorption Carbon Stock of Mangrove in Teluk Awur and Tanggul Tlare, Jepara Regency
Authors: Widyastuti Galuh , Suryanti Suryanti , Febrianto Sigit , Latifah Nurul , Ain Churun
Published: August 2023

Mangroves are one of the ecosystems that play an essential role in mitigating climate change by storing and absorbing CO2. One of the mangrove areas that can be found in Jepara Regency in Teluk Awur and Tanggul Tlare. Both of these areas is experiencing coastal abrasion, which impacts the land and mangrove areas. The reduced area of mangroves affects the ability of the ecosystem to store and absorb CO2. This study intends to determine the potential for CO2 absorption in above-ground, below-ground, and mangrove sediments. The method used in determining the station point is the purposive sampling method. While the analysis of the calculation of standing carbon storage uses allometric equations in sediments using the LOI method (Loss on Ignition). The potential for carbon absorption above-ground station 1 is 75.12 Ton.ha-1, below-ground is 51.48 Ton.ha-1, and sediment is 286.49 Ton.ha-1. While the potential for CO2 absorption at station 2 consists of 28.27 Ton.ha-1 above ground, 19.86 Ton.ha-1 underground, and 243.73 Ton.ha-1 of sediment. Based on the study’s results, the potential for CO2 absorption in the mangrove area in Teluk Awur can store more carbon than in the Tanggul Tlare mangrove area, this is supported by the diameter of the mangrove stems in Teluk Awur which has a higher size.
Occurrence of whale sharks (Rhincodon typus) in the Kwatisore Waters within the Cenderawasih Bay National Park as a basis for carrying capacity estimations and assessments for ecotourism suitability
Authors: Maruanaya Y , Sumaryono
Published: August 2023

Kwatisore waters in the Cenderawasih Bay National Park area is one of the whale sharks’ habitats in Indonesia. As shark sightings seem to occur daily there is the opportunity for ecotourism development in the area. This study aims to quantify the occurrence of whale sharks at Kwatisore, and estimate the carrying capacity of the area, together with its suitability for ecotourism based on whale shark aggregations. Primary data collection on the appearance of whale sharks was carried out every day through a census technique on 7 designated areas (Apr to Aug, 2022). Every whale shark that appears on the surface of the water is photographed and identified by an ID number based on the I3Sv2.0 and its sex determined. During the census period, 709 whale sharks’ sightings were recorded mostly in the morning. There were 15 individuals in total, all males with a total length ranging from 3-7 m. The carrying capacity of the area for whale shark ecotourism in Kwatisore waters is a maximum of 252 people per day who are allowed to interact with whale sharks, while the tourism suitability index is included in the very appropriate category for whale shark tourism.
Temporal variations in growth and condition index of kalandue clams (Polymesoda erosa, Solander 1786) in Kendari Bay, Southeast Sulawesi
Authors: Bahtiar  , Fekri L , Ishak E , Purnama M F , Permatahati Y I , Nur I
Published: August 2023

The growth and condition index of kalandue shellfish in the mangrove forest of Kendari Bay, Southeast Sulawesi is not fully known. This study aims to determine the growth and condition index of kalandue shellfish (Polymesoda erosa) in Kendari Bay, Southeast Sulawesi. Kalandue mussels were taken randomly throughout the waters using a shovel as deep as 20 cm in the aquatic substrate. Kalandue mussels were measured in length and wet weight was measured using a caliper and a digital scale with an accuracy of 0.5 mm and 0.01 g, respectively. The shells were separated by sex and dried in an oven at 70oC for 72 hours. Kalandue mussels were weighed dry and shell weight using an analytical balance with an accuracy of 0.0001g. The length-weight relationship data were analyzed using linear regression and the condition index was analyzed using the Mann Whitney test. The results showed that the length-weight relationship of males and females was in isometric conditions with values of 3.08 and 3.05, respectively. The lowest b value was found in February and the highest was in May. The condition index of male and female caladue shells was not significantly different with values of 9.26±5.50 and 6.75±4.90, respectively. The condition index experienced two peaks, namely in May and September. Furthermore, the condition index of kalandue mussels increased along with the increase in body size (shell width).
Abundance, characteristics, and distribution of microplastics in Banda Sea and Seram Sea, Indonesia
Authors: Widiaratih Rikha , Maslukah Lilik , Triyulianti Iis , Rugebregt Marsya Jaqualine , Nurhidayat  , Hascaryo Anom Puji , Sobaruddin Dyan Primana
Published: August 2023

This study recorded the abundance, characteristics, and distribution of microplastics (MPs) in the surface water in the Banda Sea and Seram Sea. The Banda Sea has known for its complex bathymetry with the shape of a basin in the west and a Sahul Shelf in the east. Due to its unique topography, it controls the water mass exchange in Indonesian waters. The Banda Sea and Seram Sea are dominated by the deep sea with bathymetry of more than 1000 m. Station observation consists of 5 stations in the Banda Sea and 3 stations in the Seram Sea. The microplastic abundance in the surface waters from the Banda Sea and Seram Sea ranged from 4.69 to 22.48 items/L with an average abundance of 14.07 items/L. The highest abundance of MPs was found in Station 1 of Banda Sea due to the closest to Ambon as the capital of Maluku Province. The dominant shape of MPs found such as fibre, fragment, and pellet. The polymer type of MPs found were PET, HDPE, LDPE, PVC, PP, and Nylon. Generally, the abundance of MPs on the surface of the deep-sea area was found lesser than in the coastal area since the MPs distributions are influenced by hydrodynamics and anthropogenic activity.
Seagrass Ecological Quality Index of Seagrass Meadows in Jepara Waters, Central Java, Indonesia
Authors: Riniatsih Ita , Hartati R , Widianingsih W , Mahendrajaya R T
Published: August 2023

In the coastal ecosystems, seagrass meadow has an ecological function as a buffer area for the health of the coral reef. In addition, this is a place to live and shelter for many early stages of marine species. Besides, they serve many services, one of which is helping mitigation of climate change by capturing and storing carbon. Because of these essential functions, this study aimed to assess the condition of seagrass meadows in Jepara (i.e., Teluk Awur, Bandengan, Panjang Island, and Blebak waters), Central Java, Indonesia, about their ecosystem quality index using. The Seagrass Ecological Quality Index (SEQI) aims to determine five resilience parameters, i.e., the richness of seagrass species, seagrass cover, macroalgae cover, epiphyte cover, and water transparency. The results of the present works showed that generally, the seagrass ecosystem in Jepara waters is in the medium Category, the SEQI of Bandengan and Panjang Island are in the moderate Category, at the poor Category in Teluk Awur and Blebak Beach. This work found the species diversity and clear water conditions in the intermediate Category. In addition, there was a decreasing trend of habitat seagrass cover and increasing epiphyte abundance and cover. This condition is closely related to the resilience of the seagrass ecosystem. Therefore, to respond to these conditions, ecological health and seagrass ecosystem conservation efforts must be focused on improving ecosystem resilience.
Relationship between osmoregulation and growth patterns of Scylla serrata gonad maturity levels in tapak mangrove waters, Semarang, Indonesia
Authors: Jati O E , Putra E A , Anggoro S , Suryanti S
Published: August 2023

Mud crab (Scylla serrata) is a species that makes up biodiversity in mangrove areas spread across the coast of the archipelago, one of which is in Tugu District, Semarang City which has a mangrove area that is still relatively good. There is a need for research to determine the viability of Scylla serrata based on environmental conditions, especially salinity which affects the osmoregulation and growth of mud crabs individually to populations. This research aims to determine osmoregulation patterns, growth patterns, and their effect on the gonadal maturity level of mud crabs. The research was carried out on April 17th 2021 at the Tapak Mangrove Area, Tugurejo Village, Semarang, Indonesia. The research object was Scylla serrata to determine hemolymph osmolarity, carapace width, weight, gonadal maturity level, and media water quality. The research method uses a descriptive exploratory method with correlation analysis. Correlation (r) analysis was carried out to determine the relationship between the two variables, namely between the value of the level of osmotic work and gonadal maturity. The osmoregulation pattern is hypoosmotic and hyperosmotic with hemolymph osmolarity at station 1 ranging from 840-899 mOsm/I H2O and station 2 ranging from 857-929 mOsm/I H2O. The Osmotic Work Rate (TKO) value at station 1 is 1-40 mOsm/I H2O and at station 2 is 2-52 mOsm/I H2O. The growth pattern is negative allometric with the condition factor at stations 1 and 2 being more than 1 (K > 1) and a K value exceeding 3 which means it is not flat. TKG (Gonadal Maturity Level) has a negative linear correlation with TKO.
Application of Acoustic Doppler Current Profile (ADCP) to Estimate Suspended Solid Concentration (SSC) During the Tidal Phase, Case Study: Donggala, Palu.
Authors: Siagian Hendry , Ismanto Aris , Prasetyawan Indra Budi , Sukmadewa Yoga , Hoir Ilham Fathul , Putra Tri Widya Laksana , Pranata Adi
Published: August 2023

Understanding various types of kite material, known as suspended solid concentration (SSC), affects the strength of the reflected acoustic signal. SSC is a concentrate that floats in a body of water, the character of the increase in concentration is strongly influenced by the transport medium, namely ocean currents and tides. The use of the Acoustic Doppler Current Profile (ADCP) in this study was developed to estimate the SSC at each elevation change in the tidal phase. This study aims to identify the relationship between the intensity of scattering values to estimate SSC, and to compare SSC temporally in the tidal phase. ADCP measurement is implemented at Donggala, Palu Waters to collected tidal behavior and strength signal during 30 days measurement, with 8 layers profile. Data analysis by classifying the relative acoustic backscatter value. The conversion of the scattering value obtained has a range between 20 - 150 db. The classification of scattering is as follows 70-77 db, 65-69 db, and 60-64 db respectively near the bottom, middle and surface waters. The results of the linear echo intensity (db) relationship with SSC observation (10log) have a strong relationship with an accuracy of R values 0.936. The characteristics of SSC at neap tide and ebb current elevation were relatively higher, with concentration values ranging from 80 – 82 mg l-1, while other conditions were 77 – 79 mg l-1. This study concludes that the intensity relationship can estimate SSC with an error of 2.61% with average layer difference concentration 0.59 mg/l.
Two dimensional Hydrodynamic Simulation in Labuan Bajo Waters, Indonesia.
Authors: Wulandari Siti , Ismanto Aris , Sugianto Denny Nugroho
Published: August 2023

Based on its strategic location, Labuan Bajo is a golden triangle between Komodo Island and Toraja Land as a national tourism sector. This makes information about the condition of Labuan Bajo waters very important. One of the oceanographic parameters that have an important role in determining the condition of a body of water is ocean currents. Ocean currents are the movement or displacement of water masses caused by waves, wind, water density, and pressure. In their movement, currents have a direction and speed that can form ocean current patterns. One method that can see patterns of sea surface currents is two-dimensional hydrodynamic modeling. This study aims to identify patterns of surface currents and tides that occur in Labuan Bajo waters. The method used in this study is quantitative descriptive with a two-dimensional hydrodynamic modeling approach along with nested-model techniques to provide the model results with a smaller resolution to get the phenomenon that occurs in those waters. The data used is bathymetry, wind, tide, and High-Frequency Radar (HF Radar) data as current validation. The results of surface current simulation in Labuan Bajo waters have the highest current of >1.12 m/s in the Western season and the lowest speed of 0.88 m/s in the Transition I season. The wind pressure gradient in the Western season affects the current speed in that season.
The Fat Oxidation that Occurs During Storage of Dried “Dendeng” with Various Spices
Authors: Aisman  , Yenrina Rina , Taib Gunarif , Rahmayanti Mia Fitri
Published: August 2023

In West Sumatra, several spices are frequently used when making dry dendeng (beef jerky). Spices are frequently added to jerky to impart flavor, color, and numerous bioactive chemicals that serve as antioxidants. This study intends to examine the influence of various spice changes on the fat oxidation that occurs during preserving dry jerky. Jerky A (Salt 25 g), Jerky B (salt 25 g, Garlic 50 g, Ginger 25 g, and Lime 2 ml), Jerky C (Salt 25 g, Garlic 25 g, Ginger 50 g, Shallots 25 g), Jerky D (Salt 25 g, Garlic 25 g, Ginger 50 g, Shallots 25 g, Coriander 2 g, Coconut Water 1,000 (Salt 25 g, Garlic 25 g, ginger 25 g, coriander 2 g, tamarind 2 g, orange leaves 2 g, galangal 50 g). The jerky has been seasoned with spices, dehydrated, and then preserved for 0 days, 20 days, 40 days, and 60 days. After 60 days of storage, the amounts of free fatty acids, TBA (Thio Barbituric Acid), and water content increased in beef jerky. Jerky B has the lowest fat oxidation, while Jerky A has the highest fat oxidation. The amount of oxidation in dry jerky during storage varies depending on the variety of seasonings used
Evaluation of land suitability as the basis for sustainable crop development
Authors: Suntoro S , Dewi W S , Syamsiyah J , Mujiyo M , Herdiansyah G , Widijanto H , Herawati A
Published: August 2023

This study aims to determine the potential and limitations of land in Ngawi District, East Java, Indonesia, for cultivating rice, corn, and soybeans. The research consists of a four-stage field study conducted in Ngawi Regency: (1) organization of land units; (2) determination of observation points through stratified proportional sampling for each land unit; (3) field surveys; and (4) laboratory analysis. The land evaluation was conducted in accordance with the FAO Guidelines for Land Evaluation for Rainfed Agriculture. The results of the research indicate that 46,417.7 ha (88.1%) of the land area is highly suitable (S1) for rice and 49,286.6 ha (72.1%) is marginally suitable (S3) for corn due to poor drainage. Approximately 62,499 ha (91.4% of the total land area) are marginally suitable (S3) for soybean cultivation. There were suggested five models of land management: (1) intensive rice farming; (2) a relay cropping system for rice-corn or rice-soybeans; (3) multiple cropping systems for corn, soybeans, or rice; (4) a mono-cultural system for rice, corn, or soybeans; and (5) an agroforestry system for Albizia chinensis, corn, and soybeans. Farmers’ awareness of organic management is crucial for enhancing land productivity and maintaining soil fertility in Ngawi Regency.
The Status and Stock of Soil Nutrients under Different Land Ownership Management of Rice Fields in Kuranji District Padang West Sumatra
Authors: Hermansah  , Astuti Yuni Sri , Darfis Irwan , Maira L , Emalinda O
Published: August 2023

This study aims to determine the status and stock of soil nutrients in three types of land ownership management. This research was conducted on smallholder farmers (SF), tenant farmers (TF), and owner farmers (OF) in Kuranji District, Padang, West Sumatra, and at the Soil Laboratory of the Faculty of Agriculture, Andalas University from March to September 2022. The range of nutrient status in the three types of land ownership is 0.06-0.35% C-organic and 0.06-0.13% N. The concentration ranges of Ca, Mg, K, Na, P, and Si, respectively, were 0.52-0.79; 0.58-1.34; 0.07-0.12; 0.03-0.09 cmol.kg-1and 2.52-12.7; 31.73- 49.33 ppm. The results showed that each management type’s status of organic carbon in soil was deficient. This result was presumably due to miss management of straws. The highest concentrations of Ca, Mg, K, and Na were found in smallholder farmers’ fields (SF), while the lowest concentrations were found in tenant farmers’ fields (TF). The stock of soil nutrients shows a similar trend to the nutrient status of the soil. The dose of fertilizer by SF and TF was 129.5 kg/ha N; 37.5 kg/ha P2O5; 37.7 kg/ha K2O, while OF is 176 kg/ha N, 65 kg/ha P2O5, 45 kg/ha K2O. The soil nutrient status among the farmer groups is not significantly related to the amount of fertilizer application. It is recommended to give a dose of fertilizer following the recommendations that have been set and balanced with the proper management of remaining straw after harvest for sustainable soil fertility and agriculture production.
Analysis of Factors Affecting Rice Production in Solok Regency
Authors: Aisy Rohadatul , Sari Devni Prima
Published: August 2023

Solok district is the largest rice-producing center in West Sumatra, known as “Bareh Solok,” with most of the population working as farmers. Land area, labor, seeds, fertilizers, capital, pesticides, and irrigation influence increased production. These seven factors are interconnected and related to each other. Hence, this study aimed to determine the factors influencing rice production in Nagari Cupak, Gunung Talang District, Solok Regency. The type of research used is applied research. This study has a sample of 89 respondents; furthermore, the analysis uses the factor analysis method. The results of this study indicate that the first factor affecting rice production consists of land area, labor, seeds, and pesticides. The second factor affecting rice production consists of fertilizer, capital, and pesticide variables.
Role of biochar on improvement of physical characteristics of re-vegetated ex coal mined soil and production of black corn (Zea mays L. var. Black Aztek)
Authors: Yulnafatmawita  , Putri Tika , Hermansah  , Haris Z.A.
Published: August 2023

Ex coal mined soil generally had problem for farming activities, even though it had been re-vegetated for few years. This research was aimed to determine the effect of biochar derived from corn cob to improve the physical characteristics of ex coal mined soil and production of black corn. A pot trial was conducted in Glasshouse at Andalas University, Padang. Soil was taken from re-vegetated of ex coal mined soil in Sawah Lunto, West Sumatra, Indonesia. The soil was mixed with biochar at 4 different doses (0; 0.5; 1.0; and 1.5%) of the weight basis. The experimental units were allocated based on Completely Randomized Design. Parameters analyzed were soil texture, bulk density (BD), total soil pore (TSP), hydraulic conductivity (HC), soil organic matter (SOM), and plant available water (PAT), as well as corn production parameters. The result showed that biochar significantly increased the SOM. SOM content at 1.5% biochar application increased by 32.4% compared to the OM content of the soil without biochar (0 T ha−1). Improving SOM due to biochar application, improved the soil physical properties, especially it decreased the soil BD (r=-0.71); increased HC (r=0.65); TSP (r=0.71); PAW (r=0.86); aeration pore (r=0.54); field capacity (r=0.83); and decreased wilting point (r=-0.66). Biochar application also improved production of black corn. It linearly increased crop height (r=0.76); corn stalk dry weight (DW) (r=0.75); grain yield DW (r=0.75); shoot DW (r=0.74); and root DW (r=0.76). Biochar derived from corn cob could be used to improve physical properties of ex coal mined soil.
Viability and responsiveness of several varieties of brown rice to salinity stress on a seedbed
Authors: Barus Wan Arfiani , Susanti Rini , Khair Hadriman , Tarigan Dafni Mawar
Published: August 2023

This study aims to determine the viability and responsiveness of several varieties of brown rice to salinity stress on seedbeds. The study was conducted from December 2019 to January 2020. The study used a factorial randomized block design, namely varieties and soil salinity levels. The brown rice varieties (V) tested were: Inpari 24 (V1), Pamelen (V2) and Pamera (V3), then the level of soil salinity (S), consisting of S0 = 0, S1 = 4-5 dS/m2, S2 = >5-6 dS/m2 and S3 = >6-7 dS/m2 soil, each with 3 replications. The parameters observed were maximum growth potential, germination, vigour index, plant height, root length, root volume, and salt injury score. The results showed that salinity stress significantly affected all observation parameters. Different varieties produced different responses to salinity stress for maximum growth potential, germination, and root volume parameters. The interaction between the two treatments also significantly affected all observation parameters, and the Inpari 24 variety was the most adaptive to salinity stress on the seedbed.