Hasil untuk "Physical geography"

V. Howard, M. Cushman, L. Pulley et al.

E. Giovannucci, Yan Liu, E. Rimm et al.

F. Dai, C. Lee

Adriane Alexandre Machado De-Melo, L. B. Almeida-Muradian, M. T. Sancho et al.

Ana L. Becerril-Sánchez, Baciliza Quintero-Salazar, O. Dublán‐García et al.

Honey has been employed since antiquity due to its sensory, nutritional, and therapeutic properties. These characteristics are related to its physical and chemical composition. For example, phenolic compounds are substances that can determine antioxidant activity, as well as sensory characteristics, and can be employed as biomarkers of floral and geographical origin. This has generated a growing interest in the study of phenolic compounds and their influence in the intrinsic properties of this beekeeping product. This review aims to summarize, analyze, and update the status of the research that demonstrates the role of phenolic compounds in antioxidant activity, botanical-geographical origin, and the sensory characteristics of honey. These phenolic compounds, according to various results reported, have great relevance in honey’s biological and functional activity. This leads to research that will link phenolic compounds to their floral, geographical, productive, and territorial origin, as well as some sensory and functional characteristics.

Nur Hussain, Md Adnan Rahman, Md Rezaul Karim et al.

Mangrove forests provide essential climate regulation and coastal protection, yet fine-scale quantification of carbon dynamics remains limited in the Sundarbans due to spatial heterogeneity and tidal influences. This study estimated canopy structural and photosynthetic dynamics from 2019 to 2023 by integrating 10 m spatial high-resolution remote sensing with a light use efficiency (LUE) modeling framework. Leaf Area Index (LAI) was retrieved at 10 m resolution using the PROSAIL radiative transfer model applied to Sentinel-2 data to characterize the canopy structure of the mangrove forest. LUE-based Gross Primary Productivity (GPP) was estimated using Sentinel-2 vegetation and water indices and MODIS fPAR with station observatory temperature data. Annual carbon uptake showed clear interannual variation, ranging from 1881 to 2862 g C m⁻² yr⁻¹ between 2019 and 2023. GPP estimates were strongly correlated with MODIS-GPP (R² = 0.86, <i>p</i> < 0.001), demonstrating the method’s reliability for monitoring mangrove carbon sequestration. LUE-based Solar-induced Chlorophyll Fluorescence (SIF) was derived at 10 m resolution and compared with TROPOMI-SIF observations to assess correspondence (R² = 0.88, <i>p</i> < 0.001) with photosynthetic activity. LAI, GPP and SIF exhibited pronounced seasonal and interannual variability on photosynthetic activity, with higher values during the monsoon growing season and lower values during dry periods. Mean NDVI declined from 2019 to 2023 and modeled annual carbon uptake ranged from approximately 43 to 65 Mt CO₂ eq, with lower sequestration in 2022–2023 associated with climatic stress. Strong correlations among LAI, NDVI, GPP, and SIF indicated consistent coupling between photosynthetic activity and carbon uptake in the mangrove ecosystem. These results provide a fine-scale assessment of mangrove carbon dynamics relevant to conservation and climate-mitigation planning in tropical regions.

J. M. Bestenlehner, Paul A. Crowther, V. A. Bronner et al.

We aim to determine the physical properties of OB stars from the multi-epoch VLT/FLAMES BLOeM spectroscopic survey of the Small Magellanic Cloud. We apply a pipeline designed to analyse large spectroscopic samples of OB stars to the co-added, initial 9 epochs of the BLOeM survey, utilising grids of synthetic model spectra computed with the stellar atmosphere code FASTWIND. 69 OB stars are excluded from the analysis owing to disk emission or significant contamination by secondaries in SB2 binaries. We determine physical properties of 778 OB stars, including Teff, log g, log L/Lsun and v_e sin i. There appears to be a bimodality in v_e sin i of single O stars, while v_e sin i distributions of OB stars are strikingly different for single (median 78 km/s) and binary (median 200 km/s) systems. Inferred temperatures are broadly in agreement with literature results for stars in common, plus results from a grid-based automization tool for a subset of O and early B stars, although uncertainties are larger for surface gravities. Rotational velocities are broadly in line with an independent tool applied to the same subset. We recover the anticipated lower mass cutoff at 8 Msun from the survey design using a Bayesian inference method coupled with SMC metallicity evolutionary models, with median masses of 12.6 Msun (19.8 Msun) for B-type (O-type) stars. Spectroscopic masses exceed evolutionary masses, albeit with large uncertainties in surface gravities. We also provide an updated catalogue of O stars in the SMC since half of the 159 BLOeM O stars are newly classified as O-type stars.

Akshay Govind Srinivasan, Vikas Dwivedi, Balaji Srinivasan

Partial differential equation (PDE) solvers are fundamental to engineering simulation. Classical mesh-based approaches (finite difference/volume/element) are fast and accurate on high-quality meshes but struggle with higher-order operators and complex, hard-to-mesh geometries. Recently developed physics-informed neural networks (PINNs) and their variants are mesh-free and flexible, yet compute-intensive and often less accurate. This paper systematically benchmarks RBF-PIELM, a rapid PINN variant-an extreme learning machine with radial-basis activations-for higher-order PDEs. RBF-PIELM replaces PINNs' time-consuming gradient descent with a single-shot least-squares solve. We test RBF-PIELM on the fourth-order biharmonic equation using two benchmarks: lid-driven cavity flow (streamfunction formulation) and a manufactured oscillatory solution. Our results show up to $(350\times)$ faster training than PINNs and over $(10\times)$ fewer parameters for comparable solution accuracy. Despite surpassing PINNs, RBF-PIELM still lags mature mesh-based solvers and its accuracy degrades on highly oscillatory solutions, highlighting remaining challenges for practical deployment.

Dongyang Yan, Alexander S. Shalin, Yongxing Wang et al.

Higher-order exceptional points (EPs) in optical structures enable ultra-sensitive responses to perturbations. However, previous investigations on higher-order EPs have predominantly focused on coupled systems, leaving their fundamental physics in open scattering systems largely unexplored. Here, we harness wave interference to realize higher-order EPs in non-Hermitian zero-index materials connected to multiple open channels. Specifically, we show that a three-channel model can give rise to three interesting types of third-order EPs: lasing EP, reflecting EP, and absorbing EP. Notably, near the third-order absorbing EP, we show ultrasensitivity -- a drastic change in output power in response to perturbations at the operating frequency -- in a purely lossy system. These findings pave the way for achieving higher-order and even arbitrary-order EPs in open scattering systems, offering significant potential for advanced sensing applications.

Bárbara Meneses-Vega, Claudio Paniconi, Christine Rivard et al.

Study region: A 700 km2 watershed near the town of Fox Creek (west-central Alberta, Canada), a region that has seen intensive oil and gas production since the 1950s, is investigated. Study focus: The overall objective is to improve our understanding of the hydrodynamics of this watershed. The hierarchical multi-model approach uses physically based numerical models and follows a stepwise progression, transitioning from saturated and variably saturated groundwater to integrated surface water–groundwater (SW-GW) models. This progression encompasses 2D and 3D configurations from a deep (∼1 km) hydrogeological multi-layer aquifer system to a shallow (45 m) coupled flow system. This differs from other multi-model studies where the focus is on comparing simple to complex models for a fixed domain. New hydrological insights for the region: The hierarchical modeling approach has led to better insights and estimates of processes including vertical recharge and lateral groundwater contributions. Moreover, it allowed us to corroborate hydraulic conductivity values and groundwater recharge despite the limited dataset. The hydraulic connections between the four non-marine bedrock units were shown to be negligible, allowing us to focus on the Paskapoo Formation. The unsaturated zone was shown to play a significant role in the model response, and accounting for land surface–subsurface dynamics was demonstrated to be critical to properly estimating hydraulic head profiles and land surface saturation patterns.

Adam Grydehøj, Ping Su, Ulunnguaq Markussen et al.

Island studies has had much to say about why understanding perceptions of islandness matters for understanding the world, and it has often questioned what islandness is. Island studies has nevertheless often taken for granted that islandness ought to be perceived and has often seen islandness as something good that requires preservation. The act of studying islands per se introduces the risk that a researcher will look for and look at islands without considering whether the islands they are seeing really exist to everyone, and whether they exist for certain other people in the ways the scholar believes them to exist. In this paper, we argue that there can never be a universally or objectively correct understanding of islands, as these are socially constructed geographical phenomena. Building upon the authors' own personal engagements with questions of islandness in China, Kalaallit Nunaat/Greenland, and Fiji, we suggest it is important for scholars to think carefully about why and how islandness matters in particular places—or else to acknowledge what motivations and power relations drive them to ascribe island status.

Hridoy Debnath, Pavel Fileviez Perez, Kevin Gonzalez-Quesada

We discuss a simple theory for physics beyond the Standard Model where a Majorana dark matter is predicted from anomaly cancellation. We discuss in detail the minimal theory where the baryon number is a local symmetry spontaneously broken at the low scale. The correlation between the cosmological constraints on the dark matter relic density, the direct detection and collider bounds is investigated. We discuss in great detail the gamma lines from dark matter annihilation showing the possibility to test these predictions in the near future at gamma-ray telescopes such as CTA. We investigate all processes contributing to the total photon flux from dark matter annihilation and point out the unique features that can be used to test this theory for dark matter.

James A. Monro, Andrew M. Kingston, David M. Paganin

Ghost projection is the reversed process of computational classical ghost imaging that allows any desired image to be synthesized using a linear combination of illuminating patterns. Typically, physical attenuating masks are used to produce these illuminating patterns. A mask-free alternative form of ghost projection is explored here, where the illuminations are a set of caustic-laden diffraction patterns known as diffraction catastrophes. These are generated by focusing a coherent beam with spatially modulated phase having random Zernike-polynomial aberrations. We demonstrate, via simulation, that a suitable linear combination of such random focal-field intensity patterns can be used as a basis to synthesize arbitrary images. In our proof-of-concept ghost-projection synthesis, the positive weighting coefficients in the decomposition are proportional to exposure times for each focal-field diffraction catastrophe. Potential applications include dynamic on-demand beam shaping of focused fields, aberration correction and lithography.

Sergei V. Kalinin, Eugene A. Eliseev, Anna N. Morozovska

The fundamental aspect of physics of ferroelectric materials is the screening of uncompensated bound charges by the dissociative adsorption of ionic charges from the environment. The adsorption of ions can be especially strong when the ferroelectric undergoes the temperature-induced transition from the paraelectric phase to the ferroelectric state. Here we demonstrate that the adsorption of ions and free radicals by the polar surface of ferroelectric nanoparticles can be very efficient in aqueous solutions due to the strong ferro-ionic coupling in the nanoparticles. Obtained results can be useful for the elaboration of alternative methods and tools for adsorption of the cations (Li+, K+, Na+, etc.), anions (Cl-, Br-, J-), and/or free radicals (CO-, NH4+, etc.) from aqueous solutions by the lead-free uniaxial ferroelectric nanoparticles. The results may become an alternative way for the environment-friendly laboratory-scale purification of different aqueous solutions from ionic contamination using controllable cyclic temperature variations.

José Morais Antunes de Sousa

O livro Tempo de Balaio (2008) do geógrafo Carlos Augusto de Figueiredo Monteiro é o primeiro livro de um conjunto de cinco volumes. No primeiro livro, o autor apresenta uma interpretação ao mesmo tempo geográfica e histórica do Estado do Piauí, enquanto que nos volumes seguintes ele se consagra à história das quatro gerações de sua família, concluindo com sua migração ao Rio de Janeiro nos anos 1940. Acompanhados de desenhos autorais, os livros compõem um quadro geral da evolução daquela sociedade entre os séculos 19 e 20. Sem deixar de ser uma leitura crítica, o presente artigo tenta compreender a argumentação central do primeiro livro, Tempo de Balaio. Procura-se destacar as inovações na análise, a beleza do texto e os problemas de método de um geógrafo que encerra sua carreira.

Балахонова Е.И.

Введение. Юбилейный для антропологии 2023 год, когда отмечалось 180 лет со дня рождения Д.Н. Анучина (1843–1923) и 140 лет со дня основания Музея антропологии Московского университета – 4 октября (по ст. ст.) 1883 года – стал отправной точкой для данного исследования. В статье впервые в отечественной литературе сделана попытка воссоздать ряд и образы людей, принимавших самое деятельное участие в формировании этнографического собрания Музея антропологии Московского университета в период его становления, когда его директором был Д.Н. Анучин. Материалы и методы. Источниками для создания статьи послужили материалы Книг поступлений, сведения из коллекционных описей и научного архива НИИ и Музея антропологии МГУ, а также данные литературы и других открытых источников. В работе использован хронологический метод. Результаты и обсуждение. Всего в статье приводятся данные о 17 собирателях, чьи имена расположены в хронологическом порядке. В статье приводятся данные о таких собирателях и дарителях, как антрополог и общественный деятель Н.Л. Гондатти (1861–1946); публицист, археолог и этнограф Н.М. Ядринцев (1842–1894); чрезвычайный посол в Бразилии, Аргентине и Уругвае А.С. Ионин (1837–1900); военный и дипломат В.Ф. Машков (1858–1932); военный, лингвист и этнограф С.Г. Леонтович (1862–?); географ и антрополог Е.И. Луценко (1876–1931); революционер и общественный деятель Ф.Я. Кон (1864–1941); энтомолог и генеалог Н.Ф. Иконников (1885–1970); собиратель коллекций, этнограф и музеевед Д.Т. Янович (1879–1940); зоолог и зоогеограф И.И. Пузанов (1885–1971); поэт К.Д. Бальмонт (1867–1942); антрополог, доктор биологических наук В.В. Троицкий (1885–1952); а также члены Второй русской экспедиции в Южную Америку (1914–1915): Г.Г. Манизер (1889–1917); Ф.А. Фиельструп (1889–1933); И.Д. Стрельников (1887–1981); Н.П. Танасийчук (1890–1960) и С.В. Гейман (1887–1975). К сожалению, размеры статьи позволяют привести лишь краткие сведения об этих людях, в то время как каждый из них достоин отдельного исследования. Заключение. В комплектовании этнографического отдела Антропологического музея в «анучинские» времена принимало участие множество людей, но, к сожалению, на сегодняшний день далеко не обо всех них удалось найти какую-либо информацию. Автор предполагает продолжить исследования.

Franziska Wolff, Sandra Lorenz, Pasi Korpelainen et al.

Detailed knowledge of vegetation patterns allows to evaluate mire ecosystems and their dynamics. The use of hyperspectral information has the benefits of exploring spectral characteristics of species and vegetation modelling. Our study employed multi-scale and multi-source hyperspectral imaging with a handheld camera in the field and an UAV (Unoccupied Aerial Vehicle) sensor covering the wavelengths of 400 – 1000 nm. Plot-level spectra acquired with a UAV and field spectra collected at 1 m height were combined to develop a spectral library for Sphagnum moss species. This library was then used to map dominant Sphagnum species in a Finnish Aapa mire complex using the Spectral Angle Mapper (SAM) classifier. Classification performance assessment was supported by calculating a water index from the UAV-information. Additionally, we examined the transferability of site-specific spectral libraries to an aapa mire with similar vegetation. The results showed little spectral variation in the plot spectrum between the sensors. A fusion of species- and plot-level libraries yielded the highest accuracy of 62 %. For both mires, there was a great variation among the class accuracies. Floating mosses had an accuracy of 86 %, followed by lawn-forming Sphagnum balticum with 77 %. For the test site, the latter species was mapped with an accuracy of 59 %. Red moss species achieved low accuracies of 45 % and 38 %, likely due to effects from sub-pixel and mixed-pixel effects of neighbouring graminoid species and the presence of litter. This might have also enhanced the contrast of adjacent pixels contributing to spectral alterations. Water table depth measurements and the water index revealed a hydrological preference for most species, with classification performance notably improving with higher water index values. We recommend collecting on-site hyperspectral information at varying hydrological circumstances to build a comprehensive spectral library for mire vegetation and modelling.

Yuya Haraguchi, Daisuke Nishio-Hamane, Hiroko Aruga Katori

In spinel-type nickelate NiRh$_2$O$_4$, magnetic ordering is observed upon the sample synthesized via kinetically controlled low-temperature solid-state metathesis, as opposed to previously-reported samples obtained through conventional solid-state reaction. Our findings are based on a combination of bulk susceptibility and specific heat measurements that disclose a N$é$el transition temperature of $T_N$ = 45 K in this material, which might feature spin-orbit entanglement in the tetragonally-coordinated $d^8$ Mott insulators. The emergence of magnetic ordering upon alteration of the synthesis route indicates that the suppression of magnetic ordering in the previous sample was rooted in the cation-mixing assisted by the entropy gain that results from high-temperature reactions. Furthermore, the $J_{\rm eff}$ = 0 physics, instead of solely the spin-only $S = 1$, describes the observed enhancement of effective magnetic moment well. Overseeing all observations and speculations, we propose that the possible mechanism responsible for the emergent magnetic orderings in NiRh$_2$O$_4$ is the condensation of $J_{\rm eff}$ = 0 exciton, driven by the interplay of the tetragonal crystal field and superexchange interactions.

Jingxu Bai, Yuechun Jiao, Rong Song et al.

Long-range $(n+2)D_{5/2} \, nF_J$ Rydberg macro-dimers are observed in an ultracold cesium Rydberg gas for $39\leq n\leq48$. Strong dipolar "flip" ($\langle D_{5/2} F_{5/2} \vert \hat{V}_{dd} \vert F_{5/2} D_{5/2} \rangle$, $\langle D_{5/2} F_{7/2} \vert \hat{V}_{dd} \vert F_{7/2} D_{5/2} \rangle$) and "cross" ($\langle D_{5/2} F_{7/2} \vert \hat{V}_{dd} \vert F_{5/2} D_{5/2} \rangle$) couplings lead to bound, fine-structure-mixed $(n+2)D_{5/2}nF_J$ macro-dimers at energies between the $F_J$ fine-structure levels. The $DF$ macro-dimers are measured by microwave photo-association from optically prepared $[(n+2)D_{5/2}]_2$ Rydberg pair states. Calculated adiabatic potential curves are used to elucidate the underlying physics and to model the $DF$ macro-dimer spectra, with good overall agreement. Microwave photo-association allows Franck-Condon tuning, which we have studied by varying the detuning of a Rydberg-atom excitation laser. Further, in Stark spectroscopy we have measured molecular DC electric polarizabilities that are considerably larger than those of the atomic states. The large molecular polarizabilities may be caused by high-$\ell$ mixing. The observed linewidths of the Stark-shifted molecular lines provide initial evidence for intra-molecular induced-dipole-dipole interaction.

P. Hoffmann, P. Hoffmann, V. Reinhart et al.

<p>Anthropogenic land use and land cover change (LULCC) is a major driver of environmental changes. The biophysical impacts of these changes on the regional climate in Europe are currently being extensively investigated within the World Climate Research Program (WCRP) Coordinated Downscaling Experiment (CORDEX) Flagship Pilot Study (FPS) Land Use and Climate Across Scales (LUCAS) using an ensemble of different regional climate models (RCMs) coupled with diverse land surface models (LSMs). In order to investigate the impact of realistic LULCC on past and future climates, high-resolution datasets with observed LULCC and projected future LULCC scenarios are required as input for the RCM–LSM simulations. To account for these needs, we generated the LUCAS Land Use and land Cover change (LUC) dataset version 1.1 at 0.1<span class="inline-formula">^∘</span> resolution for Europe with annual LULC maps from 1950 to 2100 (<a href="https://doi.org/10.26050/WDCC/LUC_hist_EU_v1.1">https://doi.org/10.26050/WDCC/LUC_hist_EU_v1.1</a>, <span class="cit" id="xref_altparen.1"><a href="#bib1.bibx35">Hoffmann et al.</a>, <a href="#bib1.bibx35">2022</a><a href="#bib1.bibx35">b</a></span>, <a href="https://doi.org/10.26050/WDCC/LUC_future_EU_v1.1">https://doi.org/10.26050/WDCC/LUC_future_EU_v1.1</a>, <span class="cit" id="xref_altparen.2"><a href="#bib1.bibx34">Hoffmann et al.</a>, <a href="#bib1.bibx34">2022</a><a href="#bib1.bibx34">a</a></span>), which is tailored to use in state-of-the-art RCMs. The plant functional type (PFT) distribution for the year 2015 (i.e. the Modelling human LAND surface Modifications and its feedbacks on local and regional cliMATE – LANDMATE – PFT dataset) is derived from the European Space Agency Climate Change Initiative Land Cover (ESA-CCI LC) dataset. Details on the conversion method, cross-walking procedure, and evaluation of the LANDMATE PFT dataset are given in the companion paper by <span class="cit" id="xref_text.3"><a href="#bib1.bibx68">Reinhart et al.</a> (<a href="#bib1.bibx68">2022</a><a href="#bib1.bibx68">b</a>)</span>. Subsequently, we applied the land use change information from the Land-Use Harmonization 2 (LUH2) dataset, provided at 0.25<span class="inline-formula">^∘</span> resolution as input for Coupled Modelling Intercomparison Project Phase 6 (CMIP6) experiments, to derive LULC distributions at<span id="page3820"/> high spatial resolution and at annual time steps from 1950 to 2100. In order to convert land use and land management change information from LUH2 into changes in the PFT distribution, we developed a land use translator (LUT) specific to the needs of RCMs. The annual PFT maps for Europe for the period 1950 to 2015 are derived from the historical LUH2 dataset by applying the LUT backward from 2015 to 1950. Historical changes in the forest type changes are considered using an additional European forest species dataset. The historical changes in the PFT distribution of LUCAS LUC follow closely the land use changes given by LUH2 but differ in some regions compared to other annual LULCC datasets. From 2016 onward, annual PFT maps for future land use change scenarios based on LUH2 are derived for different shared socioeconomic pathway (SSP) and representative concentration pathway (RCP) combinations used in the framework of CMIP6. The resulting LULCC maps can be applied as land use forcing to the new generation of RCM simulations for downscaling of CMIP6 results. The newly developed LUT is transferable to other CORDEX regions worldwide.</p>