Sign Change Research Articles

Unconventional magnetotransport properties of two-dimensional ferromagnet Fe5GeTe2

Two-dimensional (2D) van der Waals FexGeTe2 metallic ferromagnets have Curie temperature near or even higher than room temperature, showing great prospects in the field of spintronics. Here, we study the magnetotransport properties of Fe5GeTe2 nanoflakes. Multiple sign changes of angle-dependent magnetoresistance (ADMR) are observed with changing temperature or magnetic field. The high field-induced negative to positive MR transition in low temperatures (T < 50 K) and the temperature-induced sign reversal of anisotropic MR at T = 130 K are responsible for these exotic and complex characteristics of ADMR. In addition, the electron–magnon scattering induced negative MR exhibits abnormal nonmonotonic temperature dependence, which is related to the nonmonotonic variation of anomalous Hall resistance and the transition of the carrier types at T = 150 K. The exotic magnetotransport properties of Fe5GeTe2 revealed in this work may help pave the way for the practical application of this 2D magnetic material.

Morphological changes in the liver of bulls after the use of adaptogens

The paper presents the results of a study of the influence of adaptogens of plant and animal nature on the productive qualities of Kazakh white-headed bulls and morphological changes in their liver. 40 6-month-old beef bulls were selected for the study, which were divided into 4 groups: I (control) group of bulls consumed only the basic diet, II — adaptogen leucea safflower, III — drone homogenate, IV — pantocrine at the rate of 0.01 ml per 1 kg of animal body weight. At 18 months, a control slaughter of 3 animals from each group was carried out. During the experiment, it was found that the mass of the paired carcass in the bulls of the experimental groups increased by 11.1–21.7 kg (4.25–8.31%, р ≤ 0.05), the slaughter weight by 11.7–23.0 kg (4.24–8.34%, р ≤ 0.05–0.01), the slaughter yield by 0.9–1.9%. The analysis of the morphological composition of the carcass indicates an increase in the specific weight of its edible part of the carcass: by weight of muscle tissue by 4.0–7.7 kg (4.66–8.97%, р ≤ 0.05–0.01), fat — by 0.7–1.4 kg (4.67–9.33%, р ≤ 0.05). There is a high degree of maturity and high nutritional value of the meat of bulls of the experimental groups. Histological studies of the liver of bull calves indicate that when using tincture from drones, the liver structure corresponds to the norm, while in the control group animals some signs of dystrophic changes without pronounced infiltrations and signs of stagnation were found.

Examining the impact of COVID-19 disruptions on population-based breast cancer screening in Ireland.

Many population-based breast screening programmes temporarily suspended routine screening following the COVID-19 pandemic onset. This study aimed to describe screening mammography utilisation and the pattern of screen-detected breast cancer diagnoses following COVID-19-related screening disruptions in Ireland. Using anonymous aggregate data from women invited for routine screening, three time periods were examined: (1) January-December 2019, (2) January-December 2020, and (3) January-December 2021. Descriptive statistics were conducted and comparisons between groups were performed using chi-square tests. In 2020, screening mammography capacity fell by 67.1% compared to 2019; recovering to 75% of mammograms performed in 2019, during 2021. Compared to 2019, for screen-detected invasive breast cancers, a reduction in Grade 1 (14.2% vs. 17.2%) and Grade 2 tumours (53.4% vs. 58.0%) and an increase in Grade 3 tumours (32.4% vs. 24.8%) was observed in 2020 (p = 0.03); whereas an increase in Grade 2 tumours (63.3% vs. 58.0%) and a reduction in Grade 3 tumours (19.6% vs. 24.8%) was found in 2021 (p = 0.02). No changes in oestrogen receptor-positive or nodal-positive diagnoses were observed; however the proportion of oestrogen/progesterone receptor-positive breast cancers significantly increased in 2020 (76.2%; p < 0.01) and 2021 (78.7%; p < 0.001) compared to 2019 (67.8%). These findings demonstrate signs of a grade change for screen-detected invasive breast cancers early in the pandemic, with recovery evident in 2021, and without an increase in nodal positivity. Future studies are needed to determine the COVID-19 impact on long-term breast cancer outcomes including mortality.

Intravenous administration of ultrasound contrast to critically ill pediatric patients.

The off-label use of contrast-enhanced ultrasound has been increasingly used for pediatric patients. The purpose of this retrospective study is to report any observed clinical changes associated with the intravenous (IV) administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents. All critically ill patients who had 1 or more contrast-enhanced ultrasound scans while being closely monitored in the neonatal, pediatric, or pediatric cardiac intensive care units were identified. Subjective and objective data concerning cardiopulmonary, neurological, and hemodynamic monitoring were extracted from the patient's electronic medical records. Vital signs and laboratory values before, during, and after administration of ultrasound contrast were obtained. Statistical analyses were performed using JMP Pro, version 15. Results were accepted as statistically significant for P-value<0.05. Forty-seven contrast-enhanced ultrasound scans were performed on 38 critically ill patients, 2 days to 17 years old, 19 of which were female (50%), and 19 had history of prematurity (50%). At the time of the contrast-enhanced ultrasound scans, 15 patients had cardiac shunts or a patent ductus arteriosus, 25 had respiratory failure requiring invasive mechanical oxygenation and ventilation, 19 were hemodynamically unstable requiring continual vasoactive infusions, and 8 were receiving inhaled nitric oxide. In all cases, no significant respiratory, neurologic, cardiac, perfusion, or vital sign changes associated with IV ultrasound contrast were identified. This study did not retrospectively identify any adverse clinical effects associated with the IV administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents.

An efficient method for bearing fault diagnosis

Statistical features and wavelet based fault detection are attempted to find computationally less complex, low-memory, and power for real-time implementation. The mean absolute value (MAV), simple sign integral (SSI), waveform length (WL), slope sign change, and zero crossing are extracted from the vibration signal, phase current signal-1, and phase current signal-2. The extracted features are combined varyingly to obtain 31 combinations and classified using a decision tree, k-nearest neighbor {k-NN}, and support vector machine. The identified features {MAV, SSI, WL} performed better with vibration and combined current signals, with an average accuracy of 99.8% and 99.5% with the k-NN classifier, respectively. Wavelet has shown an accuracy of 98%, and the Alexnet method obtained an average accuracy of 97.5% using a combined current signal, which is less than the time domain features-based machine learning approach. In addition, simple time-domain features require memory of 9.6 MB times less than wavelets and 4.18MB times less than Alexnet. The time domain-based technique requires a computation time of 30.21 minutes less than Alexnet and 53.54 minutes less than wavelets. Experimentally, the effectiveness of identified minimal features is verified using an induction motor current signal and achieved 100% accuracy with {MAV, SSI, WL}.

Superconductivity and Charge-Density-Wave-Like Transition in Th2Cu4As5.

We report the synthesis, crystal structure, and physical properties of a novel ternary compound, Th2Cu4As5. The material crystallizes in a tetragonal structure with lattice parameters a = 4.0639(3) Å and c = 24.8221(17) Å. Its structure can be described as an alternating stacking of fluorite-type Th2As2 layers with antifluorite-type double-layered Cu4As3 slabs. The measurement of electrical resistivity, magnetic susceptibility, and specific heat reveals that Th2Cu4As5 undergoes bulk superconducting transition at 4.2 K. Additionally, all these physical quantities exhibit anomalies at 48 K, accompanied by a sign change in the Hall coefficient, suggesting a charge-density-wave-like (CDW) phase transition. Drawing from both experimental data and band calculations, we propose that the superconducting and CDW-like phase transitions are, respectively, associated with the Cu4As3 slabs and the As plane in the Th2As2 layers.

Empagliflozin and pirfenidone confer renoprotection through suppression of glycogen synthase kinase-3β and promotion of tubular regeneration in rats with induced metabolic syndrome

Metabolic syndrome (MetS) is largely coupled with chronic kidney disease (CKD). Glycogen synthase kinase-3β (GSK-3β) pathway drives tubular injury in animal models of acute kidney injury; but its contribution in CKD is still elusive. This study investigated the effect empagliflozin and/or pirfenidone against MetS-induced kidney dysfunction, and to clarify additional underpinning mechanisms particularly the GSK-3β signaling pathway. Adult male rats received 10%w/v fructose in drinking water for 20 weeks to develop MetS, then treated with either drug vehicle, empagliflozin (30 mg/kg/day) and/or pirfenidone (100 mg/kg/day) via oral gavage for subsequent 4 weeks, concurrently with the high dietary fructose. Age-matched rats receiving normal drinking water were used as controls. After 24 weeks, blood and kidneys were harvested for subsequent analyses. Rats with MetS showed signs of kidney dysfunction, structural changes and interstitial fibrosis. Activation of GSK-3β, decreased cyclinD1 expression and enhanced apoptotic signaling were found in kidneys of MetS rats. There was abundant alpha-smooth muscle actin (α-SMA) expression along with up-regulation of TGF-β1/Smad3 in kidneys of MetS rats. These derangements were almost alleviated by empagliflozin or pirfenidone, with evidence that the combined therapy was more effective than either individual drug. This study emphasizes a novel mechanism underpinning the beneficial effects of empagliflozin and pirfenidone on kidney dysfunction associated with MetS through targeting GSK-3β signaling which can mediate the regenerative capacity, anti-apoptotic effects and anti-fibrotic properties of such drugs. These findings recommend the possibility of using empagliflozin and pirfenidone as promising therapies for management of CKD in patients with MetS.

The Effects of T-2 Toxin, Deoxynivalenol, and Fumonisin B1 on Oxidative Stress-Related Genes in the Kidneys of Laying Hens.

In the context of nephrotoxic risks associated with environmental contaminants, this study focused on the impact of mycotoxin exposure on the renal health of laying hens, with particular attention to oxidative stress pathways. Sixty laying hens were assigned to three groups-a control group (CON), a low-dose mycotoxin group (LOW), and a high-dose mycotoxin group (HIGH)-and monitored for 72 h. Mycotoxin contamination involved T-2/HT-2 toxin, DON/3-AcDON/15-AcDON, and FB1 at their EU-recommended levels (low mix) and at double doses (high mix). Clinical assessments revealed no signs of toxicity or notable weight changes. Analysis of the glutathione redox system parameters demonstrated that the reduced glutathione content was lower than that in the controls at 48 h and higher at 72 h. Glutathione peroxidase activity increased in response to mycotoxin exposure. In addition, the gene expression patterns of key redox-sensitive pathways, including Keap1-Nrf2-ARE and the AhR pathway, were examined. Notably, gene expression profiles revealed dynamic responses to mycotoxin exposure over time, underscoring the intricate interplay of redox-related mechanisms in the kidney. This study sheds light on the early effects of mycotoxin mixtures on laying hens' kidneys and their potential for oxidative stress.

Future Changes in the Intensity and Duration of Marine Heat and Cold Waves: Insights from Coupled Model Initial-Condition Large Ensembles

Abstract The future evolution of sea surface temperature (SST) extremes is of great concern, not only for the health of marine ecosystems and sustainability of commercial fisheries, but also for precipitation extremes fueled by moisture evaporated from the ocean. This study examines the projected influence of anthropogenic climate change on the intensity and duration of monthly SST extremes, hereafter termed marine heat waves (MHWs) and marine cold waves (MCWs), based on initial-condition large ensembles with seven Earth system models. The large number of simulations (30–100) with each model allows for robust quantification of future changes in both the mean state and variability in each model. In general, models indicate that future changes in variability will cause MHW and MCW events to intensify in the northern extratropics and weaken in the tropics and Southern Ocean, and to shorten in duration in many areas. These changes are generally symmetric between MHWs and MCWs, except for the longitude of duration change in the tropical Pacific and sign of duration change in the Arctic. Projected changes in ENSO account for a large fraction of the variability-induced changes in MHW and MCW characteristics in each model and are responsible for much of the intermodel spread as a result of differences in future ENSO behavior. The variability-related changes in MHW and MCW characteristics noted above are superimposed upon large mean-state changes. Indeed, their contribution to the total change in SST during MHW and MCW events is generally &lt;10% except in polar regions where they contribute upward of 50%.

Proximity effect of emergent field from spin ice in an oxide heterostructure.

Geometrical frustration endows magnets with degenerate ground states, resulting in exotic spin structures and quantum phenomena. Such magnets, called quantum magnets, can display non-coplanar spin textures and be a viable platform for the topological Hall effect driven by "emergent field." However, most quantum magnets are insulators, making it challenging to electrically detect associated fluctuations and excitations. Here, we probe magnetic transitions in the spin ice insulator Dy2Ti2O7, a prototypical quantum magnet, as emergent magnetotransport phenomena at the heterointerface with the nonmagnetic metal Bi2Rh2O7. Angle-dependent longitudinal resistivity exhibits peaks at the magnetic phase boundaries of spin ice due to domain boundary scattering. In addition, the anomalous Hall resistivity undergoes a sign change with the magnetic transition in Dy2Ti2O7, reflecting the inversion of the emergent field. These findings, on the basis of epitaxial techniques, connect the fundamental research on insulating quantum magnets to their potential electronic applications, possibly leading to transformative innovations in quantum technologies.

Higher awakening threshold of preterm infants in prone position may be a risk factor for SIDS.

The supine sleeping position in the prevention of sudden infant death syndrome in preterm infants is poorly understood. We aimed to investigate the effect of sleep posture on cardiorespiratory parameters and movement patterns in preterm infants close to discharge. This observational study included neonates born in 2022 at the University Hospital Schleswig-Holstein, Lübeck, Germany. Motion sensor data, heart rate, respiratory rate and oxygen saturation were recorded for infants with postconceptional age 35-37 weeks during sleep in the prone and supine positions. We recorded data from 50 infants, born at 31 (24-35) weeks of gestation (mean(range)), aged 5.2 ± 3.7 weeks (mean ± SD), of whom 48% were female. Five typical movement patterns were identified. In the prone position, the percentage of calm, regular breathing was higher and active movement was less frequent when compared to the supine position. The percentage of calm irregular breathing, number of apnoeas, bradycardias, desaturations and vital sign changes were not influenced by position. The prone position seems to be associated with a higher arousal threshold. The supine position appears advantageous for escape from life-threatening situations such as sudden infant death syndrome.

Positive Lynden-Bell derivative as a ticket to the bar trap?

ABSTRACT We have translated the results of N-body simulations of one barred model into the language of action variables and frequencies. Using this language, we analysed the behaviour of all orbits in the model on a large time-scale at the stage of a mature bar. We show that the orbits join the bar while preserving their adiabatic invariant, which takes into account the three-dimensional structure of the orbits. This allows us to apply the concept of the Lynden-Bell derivative for each of these orbits and trace how the sign of the derivative changes; i.e. how asynchronous changes in angular momentum Lz and orbital precession rate Ωpr (normal orbital mode) change to synchronous (abnormal mode). The transition to the abnormal mode occurs when Ωpr reaches the angular velocity of the pattern Ωp, after which the orbit becomes stuck in the bar trap. All this happens against the background of secular changes in actions (Lz decreases, JR and Jz increase). At the same time, corotating particles near two stable Lagrange points are also subject to secular changes in their actions. They increase Lz and drift to the periphery, shifting corotation outwards. We also show that a change in the orbital mode from normal to abnormal and the trapping of orbits in a bar are possible only when the bar speed decreases with time, regardless of what is causing the bar to slow down. Our findings clarify and expand the picture of bar formation and evolution in numerical models.

A randomized double-blinded trial to assess recurrence of systemic allergic reactions following COVID-19 mRNA vaccination

BackgroundSystemic allergic reactions (sARs) following coronavirus disease-2019 (COVID-19) mRNA vaccines were initially reported at a higher rate than traditional vaccines. ObjectiveWe aimed to evaluate the safety of revaccination in these individuals and to interrogate mechanisms underlying these reactions. MethodsIn this randomized, double-blinded, phase 2 trial, individuals 16-69 years who previously reported a convincing sAR to their first dose of COVID-19 mRNA vaccine were randomly assigned to receive second dose of BNT162b2 (Pfizer-BioNTech; Comirnaty®) vaccine and placebo on consecutive days in a blinded, 1:1 cross-over fashion at the National Institutes of Health (NIH). Five months later, an open-label BNT162b2 booster was offered if the second dose did not result in severe sAR. None of the participants received the mRNA-1273 (Moderna; Spikevax®) vaccine during the study. The primary endpoint was recurrence of sAR following second dose and booster vaccination; exploratory endpoints included biomarker measurements. ResultsOf 111 screened individuals, 18 were randomized to receive study interventions. Eight received BNT162b2 second dose followed by placebo; eight received placebo followed by BNT162b2 second dose; two withdrew before receiving any study intervention. All 16 received the booster dose. Following second dose and booster vaccination, sARs recurred in two subjects (12.5%, 95% CI 1.6–38.3). No sAR occurred after placebo. An anaphylaxis mimic, immunization stress-related response (ISRR), occurred more commonly than sARs following both vaccine and placebo and was associated with higher pre-dose anxiety scores, paresthesias, and distinct vital sign and biomarker changes. ConclusionOur findings support revaccination of individuals who report sARs to COVID-19 mRNA vaccines. Distinct clinical and laboratory features may distinguish sARs from ISRRs.

Pressure-driven dome-shaped superconductivity in topological insulator GeBi2Te4

The discovery of new superconductors based on topological insulators always captures special attention due to their unique structural and electronic properties. High pressure is an effective way to regulate the lattice as well as electronic states in the topological insulators, thus altering their electronic properties. Herein, we report the structural and electrical transport properties of the topological insulator GeBi2Te4 by using high-pressure techniques. The synchrotron x-ray diffraction revealed that GeBi2Te4 underwent two structural phase transitions from R-3m (phase I) to C2/m (phase II) and then into Im-3m (phase III). Superconductivity was observed at 6.6 GPa to be associated with the first structural phase transition. The superconducting transition temperature Tc reached a maximum value of 8.4 K, accompanied by the RH sign changing from negative to positive at 14.6 GPa, then gradually decreased with increasing pressure in phase III, showing a dome-shaped phase diagram. The present results provide a platform for understanding the interplay between the crystal structure and superconductivity by the regulation of pressure in the topological insulator materials.

Survival Among Patients With High-Risk Gastrointestinal Cancers During the COVID-19 Pandemic

Prior reports demonstrated that patients with cancer experienced worse outcomes from pandemic-related stressors and COVID-19 infection. Patients with certain malignant neoplasms, such as high-risk gastrointestinal (HRGI) cancers, may have been particularly affected. To evaluate disruptions in care and outcomes among patients with HRGI cancers during the COVID-19 pandemic, assessing for signs of long-term changes in populations and survival. This retrospective cohort study used data from the National Cancer Database to identify patients with HRGI cancer (esophageal, gastric, primary liver, or pancreatic) diagnosed between January 1, 2018, and December 31, 2020. Data were analyzed between August 23 and September 4, 2023. Trends in monthly new cases and proportions by stage in 2020 were compared with the prior 2 years. Kaplan-Meier curves and Cox regression were used to assess 1-year mortality in 2020 compared with 2018 to 2019. Proportional monthly trends and multivariable logistic regression were used to evaluate 30-day and 90-day mortality in 2020 compared with prior years. Of the 156 937 patients included in this study, 54 994 (35.0%) were aged 60 to 69 years and 100 050 (63.8%) were men. There was a substantial decrease in newly diagnosed HRGI cancers in March to May 2020, which returned to prepandemic levels by July 2020. For stage, there was a proportional decrease in the diagnosis of stage I (-3.9%) and stage II (-2.3%) disease, with an increase in stage IV disease (7.1%) during the early months of the pandemic. Despite a slight decrease in 1-year survival rates in 2020 (50.7% in 2018 and 2019 vs 47.4% in 2020), survival curves remained unchanged between years (all P > .05). After adjusting for confounders, diagnosis in 2020 was not associated with increased 1-year mortality compared with 2018 to 2019 (hazard ratio, 0.99; 95% CI, 0.97-1.01). The rates of 30-day (2.1% in 2018, 2.0% in 2019, and 2.1% in 2020) and 90-day (4.3% in 2018, 4.4% in 2019, and 4.6% in 2020) operative mortality also remained similar. In this retrospective cohort study, a period of underdiagnosis and increase in stage IV disease was observed for HRGI cancers during the pandemic; however, there was no change in 1-year survival or operative mortality. These results demonstrate the risks associated with gaps in care and the tremendous efforts of the cancer community to ensure quality care delivery during the pandemic. Future research should investigate long-term survival changes among all cancer types as additional follow-up data are accrued.

Diagnostic accuracy of computed tomography brain perfusion in the prediction of acute ischemic stroke taking the findings of MRI as gold standard.

Objectives: To determine the diagnostic accuracy of computed tomography brain perfusion to predict acute ischemic stroke taking the findings of MRI as gold standard. Study Design: Cross-sectional Validation study. Setting: Department of Radiology Allied Hospital Faisalabad. Period: 20th May 2022 to 19th November 2022. Material &amp; Methods: A total of 215 individuals, aged between 30 and 70, of both sexes, and exhibiting ischemic stroke symptoms lasting no more than 12 hours, were included. Patients with abnormal renal function tests having renal disease were excluded. The conventional non-contrast CT used in the CT stroke protocol had basal sections that were either 3 mm or 4 mm in thickness and supra tentorial sections that were either 3 mm or 4 mm in thickness. The acquisition parameters were 80kVp and 120mAs. Dynamic CT perfusion was carried out with 4 cm plane coverage. At the seventh day, all patients underwent a follow-up MRI using a 1.5 Tesla Philips MRI scanner. A radiologist examined CTP to look for signs of early ischemic changes. For CT perfusion (CTP), measurements were taken for time to peak (TTP), cerebral blood flow (CBF), and cerebral blood volume (CBV). Results: Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of computed tomography brain perfusion in the prediction of acute ischemic stroke taking the findings of MRI as gold standard was 85.37%, 76.09%, 82.68%, 79.55% and 81.40% respectively. Conclusion: This study led to the conclusion that diagnostic accuracy of computed tomography brain perfusion to predict acute ischemic stroke is quite high.

Surface Heat Fluxes Drive a Two‐Phase Response in Southern Ocean Mode Water Stratification

AbstractSubantarctic mode waters have low stratification and are formed through subduction from thick winter mixed layers in the Southern Ocean. To investigate how surface forcing affects the stratification in mode water formation regions in the Southern Ocean, a set of adjoint sensitivity experiments are conducted. The objective function is the annual‐average stratification over the mode water formation region, which is evaluated from potential temperature and salinity adjoint sensitivity experiments. The analysis of impacts, from the product of sensitivities and forcing variability, identifies the separate effects of the wind stress, heat flux, and freshwater flux, revealing that the dominant control on stratification is from surface heat fluxes, as well as a smaller effect from zonal wind stress. The adjoint sensitivities of stratification to surface heat flux reveal a surprising change in sign over 2 years lead time: surface cooling leads to the expected initial local decrease in stratification, but there is a delayed response leading to an increase in stratification. This delayed response in stratification involves effective atmospheric damping of the surface thermal contribution, so that eventually the oppositely‐signed advective haline contribution dominates. This two‐phase response of stratification is found to hold over mode water formation regions in the South Indian and Southeast Pacific sectors of the Southern Ocean, where there are strong advective flows linked to the Antarctic Circumpolar Current.

On a class of Kirchhoff type logarithmic Schrödinger equations involving the critical or supercritical Sobolev exponent

In this paper, we study a class of Kirchhoff type logarithmic Schrödinger equations involving the critical or supercritical Sobolev exponent. Such problems cannot be studied by applying variational methods in a standard way, because the nonlinearities do not satisfy the Ambrosetti-Rabinowitz condition and change sign. Moreover, the appearance of the logarithmic term makes the associated energy functional lose differentiable in the sense of Gateaux. By analyzing the structure of the Nehari manifold and developing some analysis techniques, the above obstacles are overcome in subtle ways and several existence result are obtained. Furthermore, we investigate the regularity, the monotonicity, and the symmetric properties of the solutions via the iterative technique and the moving plane method.

Spin Pumping from Lu3Fe5O12

Microwave spin pumping from ferromagnetic lutetium iron garnet (Lu3Fe5O12) has been theoretically and experimentally investigated. The magnetization vector precession excited by a microwave magnetic field is transformed into a dc voltage due to the inverse spin Hall effect in the lutetium iron garnet/heavy metal heterostructure (Lu3Fe5O12/Pt). In the experiments carried out, the external magnetic field has been varied from 0 to 6 kOe, thus making it possible to tune the resonant frequency in wide ranges. The experimental sensitivity of this heterostructure is 8.2 µV/W. A change in the dc voltage sign with a change in the magnetic field direction confirms the generation of spin current in the Lu3Fe5O12/Pt heterostructure. The results obtained make a significant contribution to insight into spin pumping physics and may be useful for the development of new highly sensitive tunable spintronic devices.

Estimation of Carbon Stock Due to Land Cover Change in Small Islands: A Case of Gili Matra Islands, Indonesia’s Marine Tourism Park

As a small island cluster, Gili Matra (Meno, Trawangan, and Air) is the main tourist attraction in West Nusa Tenggara. The trend of population growth in Gili Matra, as well as the trend of tourist visits, continues to increase. It needs to be more balanced between the demand for living space and developing tourism-supporting facilities. As a result, land cover changes are unavoidable, significantly reducing the non-built-up areas. Land cover changes have an impact on ecosystem and climate control functions. The signs of climate change in small islands, such as extreme weather, sea level rise, and coastal abrasion, are starting to be felt. The purpose of this study is to calculate the conversion of carbon stocks based on land cover changes in Gili Matra from 2013 to 2022. The analytical method used to land cover change and analyse carbon stocks. The research showed that the built-up areas increased from 126.84 hectares to 223.55 hectares from 2013 to 2022. Meanwhile, non-built-up areas such as sand beaches, plantations, bare areas, shrubs, and mangrove areas decreased from 576.56 to 479.84 hectares. In addition, mangroves, plantations, and shrubs, three examples of land cover with the highest carbon conversion, have decreased by 28.67%, 11.25%, and 6.36%, respectively. The total carbon stock on Gili Matra in the 2013–2022 period has decreased by 1,802.08 tons C. It indicates increased carbon emissions due to land cover changes in Gili Matra caused by increased demands on space for settlements and tourism support facilities.