bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating Above-Ground Carbon of Taurus Cedar Stands Using Sentinel-2 Satellite Image: A Case Study of Elmalı Forest Enterprise
Authors: Demirel Döndü , Günlü Alkan , Sakıcı Oytun Emre
Published: November 2023

Most terrestrial carbon (C) is stored in forests, an important source of fiber and fuel for humans. Therefore, forests play an essential role in mitigating the effects of climate change by reducing the carbon level in the atmosphere. Field measurements and remote sensing techniques determine the stored above-ground carbon (AGC). This study used Sentinel-2 satellite image to estimate the amount of AGC in pure Taurus cedar (Cedrus libani A. Rich.) stands in Elmalı Forest Enterprise. Regression models were developed for AGC estimation with the reflectance and vegetation indices obtained from the Sentinel-2 satellite image. Within the scope of the study, the field measurement data obtained from 120 sample plots were used and AGCs of their corresponding stands were estimated with an allometric equation. The sample plots data was randomly divided into modeling (70%, 84 sample plots) and control data (30%, 36 sample plots) to fit the regression models and to test the accuracy of the models, respectively. Multiple linear regression analysis were conducted to develop the models, and three goodness-of-fit statistics (R2, RMSE and MAE) were used to compare the success of these models. When the achievements of the models were evaluated, it was revealed that the model containing the MSR vegetation indice gave more successful results (R2=0.488). Consequently, it was determined that the developed models were moderately successful in estimating AGC.
Variation of Aluminum Concentrations in Annual Rings of Some Trees Growing in Ankara City Center Depending on Years and Species
Authors: Yayla Emine Emel , Şevik Hakan
Published: November 2023

Heavy metal pollution is one of the most critical concerns threatening environmental and individual health worldwide in the last century. Heavy metals in the air have particular importance due to their effects on human health. Therefore, watching the difference in heavy metal pollution in the airborne is extremely important. Tree annual rings are the most efficient biomonitors used to define the differences in heavy metal concentration levels in the airborne during the years. However, the accumulation of each element in tree annual rings varies depending on the species. Therefore, it is necessary to determine the species that can be used as biomonitors separately in determining the difference in the concentration of each element in the air over the years. This study aimed to determine the variation of Aluminum (Al) concentration in the air in the last 30 years in Ankara city center by using the annual rings of Platanus orientalis, Elaeagnus angustifolia L., Koelreuteria paniculata Laxm, Cedrus atlantica (Endl.) Manetti ex Carr. Ailanthus altissima (Mill.) Swingle trees. As a result, the maximum aluminum concentrations were found in the outer bark of all species. The maximum concentrations were found in Platanus orientalis L. in the wood part.
Carbon Concentrations of Some Shrub Species Involved in Understory Vegetation in Istanbul-Durusu Sand Dune Afforestations
Authors: Pehlivan Servet , Özturna Alper Gün
Published: November 2023

Forests are one of the most significant carbon pools in terrestrial ecosystems. Forests store carbon not only in the tree biomass that composes them but also in pools such as dead wood, litter, and soil. Similarly, vegetation elements, which are components of forest ecosystems and are referred to as understory in forestry practice, are also constituents of the forest ecosystems' primary living biomass pool. On the carbon accumulation in forest ecosystems in Türkiye a substantial number of studies have been or are being conducted but this is still insufficient. However, the vast majority of these studies involve tree biomass (particularly above-ground biomass). Some subsequent studies have focused on carbon in litter and soil. But as stated previously, studies attempting to ascertain the amount of carbon stored in the understory biomass, which is a component of the living biomass pool and a part of the forest vegetation, are almost nonexistent. Consequently, the aim of this study is to determine the carbon concentrations of the shrub part of the vegetation on a coastal dune (Durusu (Terkos) Sand Dune) that had zero carbon stock prior to 60 years ago afforestation. During the biomass inventory of the maritime pine and stone pine plantations in Durusu Sand Dune, the carbon content of the shrub species was determined by collecting samples from a total of 18 sample plots. Both the above- and below-ground portions of the plants were sampled independently for shrubs. During the inventory investigations, the following species of shrubs were identified: arbutus (Arbutus unedo), heather (Erica arborea), cistus (Cistus creticus), laurel (Laurus nobilis) and broom (Sarathommus scoparius). Using the LECO TruSpec 2000 C/N Analyzer, the carbon concentrations of the leaves, branch/stem wood and root organs of these shrub species were determined via the dry burning method. The carbon contents of the leaf, branch/stem wood, and root components of arbutus species were measured and found to be 48.37%, 47.77%, and 47.47%, respectively. The carbon contents in heather species were found to be 51.62%, 50.26%, and 50.64%, while in laurel species, they were revealed to be 51.27%, 48.43%, and 48.28%. The carbon factors of the three biomass components in the broom species are 48.59%, 47.54%, and 48.98%, respectively. The present study investigated the biomass components of the cistus species, specifically classifying them into above-ground and below-ground categories. Additionally, carbon ratios were found for these components. The carbon ratio of the above-ground organs of the cistus species was found to be 48.96%, whereas the carbon ratio of the below-ground organs was determined to be 47.97%.
Seed Reduplication of the Flowering Plants of the Disturbed Landscapes in the Northern of Far-East of Asia
Authors: Tikhmenev Evgeny , Tikhmenev Pavel Evgenievich
Published: November 2023

The results of studies of anthropogenic landscapes functioning with an assessment on the processes natural self-revegetation and effectivity of reclamation in tundra, forest-tundra, larch forest complexes are summarized. The principles of accelerated restoration of the ecological and aesthetic value of disturbed landscapes at the permafrost zone are substantiated, based on the data obtained during studying the self-revegetation and reclamation processes on disturbed complexes. Development of placer and ore deposits of mineral resources is leading to deep transformation of landscape and to destruction of soil-vegetation complexes. The processes caused by mining activity are leading to variable mechanisms of degradation of soil and vegetation often having complex impact. Results of study of sustainability of soil-vegetable complexes to the impact of mancaused activity have showed the dependence from the structure of soil profile and it characteristic, from the character of genetic horizons, frozen status of the landscape elements, form of the structure, biomass and seed productivity. The rate of fertilization and fruiting regularity of perspective some species of native flora for introduction as medical, nutritive or fodder plants was also determined.
How Forest Management Can Improve Carbon Sequestration, Carbon Stock and Other Ecosystem Services? A Focus on Mediterranean Environment
Authors: Chiavetta Ugo
Published: November 2023

Forests play a crucial role in mitigating climate change by sequestering carbon and providing various ecosystem services. This contribute explores the relationship between forest management practices and their impacts on carbon sequestration, carbon stock, and other ecosystem services, with a specific focus on the unique challenges and opportunities presented by Mediterranean environments. Drawing from a synthesis of existing research, I discuss the effectiveness of different forest management strategies in enhancing carbon sequestration and carbon stock while considering the broader ecosystem services provided by Mediterranean forests. I also include a case study on thinning in peri-urban forest stand, highlighting its potential to enhance carbon sequestration and ecosystem services in Mediterranean peri-urban areas. I underline the importance of sustainable forest management practices in mitigating climate change and supporting biodiversity conservation in this ecologically sensitive region. Furthermore, we identify key knowledge gaps and research priorities to guide future efforts in optimizing forest management for both carbon sequestration and ecosystem resilience in Mediterranean environments.
Protected Areas for Biodiversity Conservation in Morocco
Authors: Alaoui Assmaa
Published: November 2023

On a global scale, human activities and unsustainable consumption and production patterns have, over the last century, led to an erosion of biodiversity, manifested by a major wave of ecosystem degradation and species extinction. Faced with this alarming situation, and in recognition of the importance of biodiversity for humanity, governments have adopted several conventions aimed essentially at conserving biodiversity. Aware of the threats of degradation to biodiversity, and in order to honor its international commitments by ratifying several conventions, Morocco has drawn up a Master Plan for Protected Areas (1996), which aims to evaluate the main natural environments over a surface area of 2.5 million hectares, and to identify 154 Sites of Biological and Ecological Interest (SIBE). The aim of this work is to present a diagnosis of the current situation, the importance and evolution of the diversity of natural ecosystems and the role of protected areas in biodiversity conservation, through case studies in Morocco.
King of the Desert
Authors: Omirzak Nurtore , Boranbay Zhumagul
Published: November 2023

The saxaul plant, which is considered an integral part of nature, is considered, its morphology, and economic importance. Saxaul, which became the “King of the desert”, did not lose its value and holiness, no matter how much time passed. Only the generation of each era, not understanding its value, creates the danger of saxaul disappearing from the face of the earth. This, of course, is a great abuse, first of nature, and then of humanity. Saxaul is used when planting field-protective forests, planting in sand, especially in sand with saline soil. Saxaul is a fortress of the sandy desert. That is, it holds the sand tightly. Saxaul is the living depths of the desert.
Knowledge, Attitudes and Practices (KAPs) on Food Safety Among Food Handlers in School Canteens in Eastern Visayas, Philippines
Authors: Pet Anthony L. Pascual  , Leonido P. Olobia  , Gladys Ludevese-Pascual  , Neuville Florinth Lucrese D. Abenis
Published: November 2023

The present study was conducted to evaluate the levels of knowledge, attitudes and practices (KAPs) on food safety among food handlers in different high school canteens in Eastern Visayas, Philippines. Of the 26 respondents, the were between 36-45 years (23.1%), are females (76.9%), reached tertiary education (73.1%), and obtained food safety-related trainings (50%). When it came to foodborne disease transmission, 96.2%, 88.5%, and 73.1% of the respondents know that Salmonella, hepatitis A virus and Staphylococcus aureus, respectively, are foodborne pathogens. Yet some of the respondents (38.4%) did not know that microbes can be in the skin, nose and mouth of a healthy food handler. The overall satisfactory knowledge of food safety among the respondents did not however translate into positive attitudes and satisfactory practices on food safety. The majority of the respondents were unaware of the appropriate way in thawing meat products (57.7% wrong answers); 53.8% of the respondents practiced refreezing of defrosted food products, and washing of eggs soon after purchase. Although the majority of the respondents (80.8%) knew that eating and drinking in the workplace increased the risk of food contamination, 53.8% of these respondents still report eating and drinking during working hours. Overall, findings revealed that adequate knowledge on food safety will not necessarily translate into positive attitudes and good practices on food safety. Thus, continuous food safety education and subsequent monitoring and evaluation are a must. Strategies to motivate food handlers in pursuing food safety procedures are also recommended.
Process Optimization of Lactic Acid Treated EVIARC Sweet Jackfruit (Artocarpus heterophyllus Lam.) Flour
Authors: Maria Norfrelij J. Cuadra  , Lorina A. Galvez
Published: November 2023

Jackfruit seeds is a cheap source of nutrients but are usually discarded as waste hence, it is transformed into flour product where it can be kept and used for a longer period. However, it has limited cooking applications. There is a need, thus, to expand its range of application by modifying its properties which can be achieved by treating it with lactic acid. The study aimed to optimize the process of lactic acid treated jackfruit seed flour using Response Surface Methodology. A 3x3 full factorial design following Completely Randomized Design (CRD) with different levels of lactic acid (0, 1.5, 3 % v/v) and soaking time (16, 24, 32 hours) were used for physico-chemical and functional properties evaluation. Optimum treatment for lactic acid treated jackfruit seeds flour production is 1.5% v/v lactic acid and 21 hours of soaking time. Predictive ability of the model equation developed for the optimum process was verified.
Delivery System for Enhanced Efficacy of Trichoderma harzianum against Fusarium Wilt of Lakatan Banana
Authors: Belly T. Dionio  , Larry V. Aceres  , Darryl Kynth B. Pontillo  , Mary Amor G. Figueroa
Published: November 2023

Biological control is a potential approach in the management of Fusarium wilt (Foc) of banana. To be effective, however, biological disease control depends not only on suitable biocontrol organisms but also on methods and strategies of introducing and maintaining these organisms in association with plants. This paper presents the influence of delivery systems on the efficacy of Trichoderma harzianum for Fusarium wilt control in ‘Lakatan’ banana. T. harzianum was applied prior to transplanting and during transplanting in 30 cm X 30 cm polypropylene bags with follow-up application of T. harzianum in the forms of conidial suspension every two weeks or in substrate at monthly intervals. Negative and positive controls were provided. Among the delivery systems, disease incidence and severity and Foc colony-forming units (CFU) per gram of substrate were significantly (p <0.001) low in meriplants grown in T. harzianum-inoculated planting medium with basal and monthly follow-up application of T. harzianum in substrate or composted coco coir dust (67% incidence; disease severity index (DSI)=2.0; cfu/g medium=2,050). The effects were comparable to incorporation of T. harzianum in the potting medium of three-week-old plants with basal application of T. harzianum in substrate at transplanting and follow-up application of T. harzianum suspension every two weeks (60% incidence; DSI=2.1; cfu/g medium=5,790). Likewise, comparable results were obtained with pre-treated three-week-old potted plants with basal application of T. harzianum in substrate at transplanting but no follow-up application of T. harzianum (67% incidence; DSI=2.1; cfu/g medium=6,240). Costs incurred per plant in the application of T. harzianum were P2.41, P3.03, and P1.28, respectively.
Cost and Return Analysis of Establishing a Science and Technology-Based (STBF) Ampalaya (Momordica charantia) Farm
Authors: Nestor O. Morales  , Veronica L. Reoma  , Dewoowoogen P. Baclayon  , Ike Mantilla  , Tamar B. Mejia, Jr.
Published: November 2023

A STBF was established in Molopolo, Macrohon, Southern Leyte showcasing best management practices for organic-based ampalaya production. Two demo plots were established, one was following the MS practice and the other adopting new interventions. The plots with interventions had better crop growth. Yields were 70%, 80% and 42% higher than the MS practice plots in the first, second and third cropping, respectively. Net income change of P21,800.00, P27,420.00 and P10,335.00 were obtained during the three croppings. Field day participants’ feedbacks indicated that the scientific way of organic ampalaya production was more beneficial than the MS usual practice.
The determinants affecting performance of the oil and gas industry in Vietnam
Authors:   UEH University, Tran Anh Tuan Thi , Nguyen Binh Quoc , Nguyen Chanh Trung , Nguyen Nam Viet , Nguyen An Thuy Phuong
Published: November 2023

This study analyzed the impact of macroeconomic and financial factors on the performance of oil and gas companies listed on the Vietnamese stock market between 2012 and 2021. The findings of the research suggest that financial leverage, fixed asset ratio, exchange rate, and inflation rate negatively affect the performance of oil and gas companies. Conversely, company size, long-term debt ratio, and listing status positively impact the performance of these businesses. Furthermore, the research indicates that these financial and macro factors consistently impact the performance of oil and gas enterprises before and after their listing on the stock exchange. The study also highlights the changes in the factors that affect oil and gas companies during the COVID-19 pandemic. For instance, the leverage ratio, fixed asset ratio, long-term debt ratio, and inflation rate have been impacted by the pandemic. The results of this study provide managers with an understanding of the factors that affect the efficiency of oil and gas enterprises. As a result, they can make informed decisions when operating their businesses.
The FDI role in economic development: A study of Vietnam
Authors:   Thu Dau Mot University, Hoang Long Hoang Nguyen , Le Long Ma
Published: November 2023

This study aims to investigate the role of Foreign direct investment (FDI) in Economic development by assessing its relationship with GDP per capita in Vietnam during the period 1986-2020 through descriptive statistical, correlation matrix analysis, and the Vector error correction model (VECM) with time-series data. The empirical results show that FDI has a significant positive relationship with Economic development in the short run, while not finding a long-run relationship. In addition, it is found that a clear relationship between Exports and Economic development in both the short run and long run. Meanwhile, CO2 emissions and Employment opportunites have no clear relationship with Economic development in the short run, however the relationship is reserved in the long run. From these findings, authors propose some policy implications of attaching FDI to sustainable Economic development in Vietnam in the coming time.
Digital Transformation: A dispensable trend for Vietnam State Treasury
Authors:   Van Lang University, Nguyen Duong Thanh
Published: November 2023

The comprehensive renewal, improvement, and modernization of the national financial system are urgently needed. The State Treasury, with its assigned functions and duties, plays a positive role in promoting the sustainable development of the national financial system and ensuring the resources for the state to maintain socio-economic development. This reality calls for specific and effective solutions to achieve the goals of the digital State Treasury. This is also a prerequysite to ensure the implementation of the e-government goals, which serve as the foundation for the national digital transformation strategy. The article aims to study the theoretical basis of the digital State Treasury, including crucial content regarding the overall architecture of the digital State Treasury model, the conditions for the formation of the digital State Treasury, the initial digital transformation results of the State Treasury of Vietnam, and some recommendations for the development of the digital State Treasury.
O impacto da rotina de pausas ativas no ambiente de trabalho na percepção de estresse, dor e qualidade do sono em trabalhadores administrativos
Authors: Sandy Daniel Dias , Batista-Ferreira Leandra , Rodrigues Bernardo Minelli
Published: November 2023

Introdução: O sedentarismo comportamental é considerado um grave problema de saúde pública no mundo. O estresse, lombalgia e a má qualidade do sono estão entre as maiores causas de presenteísmo e afastamento no ambiente de trabalho e uma melhor gestão do sedentarismo durante a jornada pode ser um promotor de saúde e produtividade dos trabalhadores. Objetivo: Investigar o impacto da introdução da rotina de pausas ativas na atividade física diária, na autopercepção do estresse, lombalgia e qualidade do sono em trabalhadores administrativos. Método: Estudo descritivo-exploratório realizado com 114 profissionais administrativos de ambos os sexos (76% mulheres). Os participantes foram orientados a seguir uma rotina de pausas ativas durante 12 semanas com apoio de um aplicativo (APP) e foi utilizado um questionário pré e pós intervenção. Resultados/Discussão: Antes da intervenção 75,4% dos trabalhadores não realizavam pausas ativas. Após intervenção 39,5% dos trabalhadores passaram a praticar pelo menos 1 pausa ativa diariamente e 44% passaram a fazer 2 ou mais pausas ativas por dia (p=0.01). Foi observada uma redução significativa na percepção do estresse (p=0,004) e de dores lombares durante a jornada (p<0,001), sendo que 32% dos participantes alegaram não sentirem mais dor após a intervenção. Além disso, observamos uma melhora na qualidade do sono (p=0,001) e aumento significativo na frequência de exercício semanal no grupo (p<0,0001) Os resultados indicam uma associação positiva entre a gestão do comportamento sedentário no ambiente de trabalho e percepção de sinais relacionados ao estresse físico e mental. Conclusão: A rotina de pausas ativas no ambiente de trabalho parece ter um impacto positivo no sedentarismo, na redução da percepção dor, estresse e qualidade do sono em trabalhadores administrativos, podendo fazer parte de orientações ergonômicas para empregadores e órgãos regulatórios. A incorporação dessa rotina pode resultar em funcionários mais ativos e menos reativos ao estresse físico e psicofisiológico relacionado ao trabalho, promovendo assim um ambiente de trabalho mais saudável e produtivo, além de impactar na qualidade do sono e ser um potencializador do aumento da atividade física no período de lazer.
PERANCANGAN SASARAN STRATEGIS UNTUK KINERJA DISTRIBUSI BERAS MENGGUNAKAN PERSPEKTIF BALANCED SCORECARD DAN AHP
Authors: Falah Agni Nur , Lestiani Melia Eka
Published: November 2023

Distribusi merupakan suatu kegiatan logistik outbound, dimana kegiatan ini menjadi salah satu hal penting pada perusahaan yang memproduksi barang, hal ini berkaitan dengan proses penyaluran dan penjualan barang untuk tetap menjaga kualitas tersebut dibutuhkan sasaran strategis distribusi yang tepat, maka penelitian ini difokuskan untuk merancang sasaran strategis sebagai dasar pengendalian kualitas pelayanandistribusi beras yang belum dimiliki oleh PT. X pada penelitian ini teori yang digunakan berkaitan dengan distribusi, penilaian kinerja, analisis kriteria menggunakan balanced scorecard dan delphi, lalu pembobotan menggunakan analytical hierarcy process. Didapatkan 10 sasaran strategis dengan 16 alternatif yang akan menjadi poin kinerja pelayanan distribusi pada PT. X dimana diketahui bahwa tingkat keluhan yang diterima menjadi ukuran kinerja tertinggi yang harus diperhatikan dengan bobot sebesar 0,066. Sementara untuk ukuran kinerja terendah didapatkan oleh transaksi yang tidak dapat dipenuhi dengan bobot sebesar 0,059.maka disimpulkan bahwa dasar pengendalian kualitas pelayanan distribusi pada PT. X yang dirancang menggunakan perspektif balanced scorecard menghasilkan 16 ukuran kinerja dari 10 tujuan strategis berdasarkan 4 perspektif utama yang melalui berbagai tahap, mulai dari pengidentifikasian tujuan strategis dan ukuran kinerja melalui studi literatur dan wawancara, memeriksa tingkat keperluan ukuran tersebut dengan metode delphi, Lalu dilanjutkan dengan pembobotan pada ukuran untuk menentukan prioritas dari masing masing ukuran kinerja sehingga didapatkan hasil akhir sasaran strategis dengan bobotnya.
Analisis Keterbukaan Ekonomi Dan Ekspor Di Indonesia: Studi Empiris Pada Dampak Covid-19 Dan Peperangan Rusia-Ukraina
Authors: Rachman M. Aulia
Published: November 2023

Global economic uncertainty due to the Covid-19 pandemic and the Russia-Ukraine war has had an impact on the supply chain of goods and services. In the midst of global economic turmoil, Indonesia's trade performance has had a positive average trade balance in the last 5 years. This study examines the impact of economic conditions on trade openness and exports in Indonesia, and assesses the impact of the Covid-19 pandemic and the Russia-Ukraine War. The research method used is ARDL to to examine the short-run and long-run effects of variables using monthly data from 2017 to 2022. The findings show that the Inflation variable has a positive impact on trade openness and exports in Indonesia, this contradiction with Romer's hypothesis and implies that the possibility of Indonesia's international trade is in line with the approach of the Ricardian model. The addition of Covid-19 cases has a negative impact on trade openness, while the pandemic period has a positive impact on exports. The variables of the Russia-Ukraine war have a negative but not significant impact. Policy recommendations are to maintain domestic productivity in order to maintain the needs of goods and services, as well as domestic and foreign supply chains
L’île voyageuse : Tobago et la pensée impériale française, 1713-1763
Authors: Boutinot Ségolène
Published: November 2023

L’étude de l’île de Tobago contribue à souligner une stratégie impériale française au XVIIIe siècle. À partir de l’examen de plusieurs cartes publiées tant en France qu’en Angleterre, cette recherche montre comment des discours sont produits alors que Tobago n’est physiquement occupée par aucune puissance européenne. Les cartes ont en effet un caractère discursif. L’indétermination du statut de Tobago n’empêche pas les cartographes de l’attribuer à telle ou telle puissance européenne, selon leur proximité avec le pouvoir. Des représentations de Tobago sont ainsi véhiculées. Elles permettent de connaître, s’approprier et revendiquer une île. Elles contribuent à l’invention d’un territoire. Les représentations cartographiques rendent compte d’une pensée impériale, prenant en compte un ensemble de territoires, envisagés les uns par rapport aux autres selon le contexte métropolitain.
‘Fake news’: intento de alto el fuego
Authors: Martínez Martínez Silvia
Published: November 2023

En los últimos tiempos, cada gran acontecimiento informativo ha sido bombardeado por bulos y mentiras. Los intereses detrás de estos ataques con fake news pueden ser variados y, aunque resulta difícil medir sus efectos, es evidente el impacto que tienen en la sociedad, en su capacidad de actuar y decidir. La guerra en Israel no está exenta de la escalada de noticias falsas, mientras la UE se pone a prueba en su intento por lograr un alto al fuego que detenga las campañas de desinformación.
RESPONSE OF MONETARY POLICY ON CLIMATE CHANGES
Authors: Lukić Velimir , Popović Svetlana
Published: November 2023

The world has commenced a transition towards sustainable development that respects the need to preserve the environment. Central banks are making efforts to encourage and facilitate the transition to a sustainable finance model that is a prerequisite for a green transition. Central banks have been working intensively on adjusting the existing framework for the implementation of monetary policy in the light of the requirements for the incorporation of climate considerations, so the paper provides an overview and analysis of possible changes in the framework. The conclusion of the paper is that central banks must be careful in weighing the respective measures so as not to jeopardize their primary goal - price stability.
ДИГИТАЛНА ТРАНСФОРМАЦИЈА КАО ЕКОНОМСКИ ИЗАЗОВ У УСЛОВИМА УБРЗАНИХ ГЛОБАЛНИХ ПРОМЕНА
Authors: Станкић Раде , Солдић-Алексић Jасна , Јаковљевић Александра
Published: November 2023

Масовна примена дигиталних технологија унела је суштинске промене и у пословно окружење и свакодневни живот људи. Дигитална трансформација изазива жестоку дебату међу креаторима политике, економистима и индустријским лидерима о њеном друштвеном утицају и економским изазовима. О ефектима и последицама дигитализације и дигиталне трансформације често се јављају супротстављени ставови, почев од потпуно оптимистичких о будућим трендовима, па до оних који истичу разлоге за забринутост због евентуалног њиховог негативног утицаја. Циљ овог рада јесте да укаже на најзначајније економске изазове дигиталне трансформације у условима убрзаних глобалних промена. У раду је посебно наглашено да дигитална трансформација у неким областима прави „дисруптивни хаос“, док истовремено у другим областима доводи до унапређења пословања. Такође, у раду је посебно разматрана позиција Србије с аспекта економских изазова које доноси дигитализација и дигитална трансформација. Убрзане глобалне промене које су условљене развојем технологија захтевају да се све економије, уколико желе да буду успешне, морају прилагодити ,,дигиталном времену“. У том прилагођавању посебно је важно избећи евентуалне негативне утицаје дигитализације и примене дигитаних технологија у свим сферама живота и у пословном окружењу, а нарачито да не дође до стварања или увећавања дигиталног јаза у свим својим појавним облицима, а неки од њих су у овом раду посебно апострофирани.
Effect of heavy ion radiation on low frequency noise characteristics of AlGaN/GaN high electron mobility transistors
Authors: Lü Ling , Xing Mu-Han , Xue Bo-Rui , Cao Yan-Rong , Hu Pei-Pei , Zheng Xue-Feng , Ma Xiao-Hua , Hao Yue ,   School of Microelectronics, Xidian University, Xi’an 710071, China,   School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071, China,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Published: November 2023

AlGaN/GaN high election mobility transistor (HEMT) has important application prospects in satellite communication, radar, nuclear reactors and other extreme environments, owing to its excellent electrical performance and strong radiation resistance. Heavy ion radiation mainly causes single-event effect and displacement damage effect in AlGaN/GaN HEMT device. In this work, the displacement damage defects introduced by heavy ion radiation are analyzed in detail. With the increase of heavy ion radiation influence, more defects are introduced by displacement damage. These defects reduce the two-dimensional electron gas (2DEG) concentration through carrier capture and removal effect, and reduce the carrier mobility through scattering mechanism, resulting in gradual degradation of the electrical characteristics of the device. In this work, AlGaN/GaN high electron mobility transistors are irradiated by 181Ta32+ ions with fluences of 1×108 ions/cm2, 1×109 ions/cm2 and 1×1010 ions/cm2. The electrical characteristics, EMMI and low-frequency noise characteristics of the device before and after heavy ion radiation are measured. The results show that heavy ion radiation can lead to the degradation of electrical parameters. When the heavy ion radiation dose reaches 1×1010 ions/cm2, the electrical characteristics of the device deteriorate seriously, the threshold voltage shifts forward by 25%, and the drain saturation current deteriorates obviously. The defect locations introduced by irradiation are analyzed by EMMI test, and it is found that the number of “hot spots” increases significantly after the having been irradiated by heavy ions with a fluence of 1×1010 ions/cm2, indicating that the radiation leads to the increase of defect density and serious damage to the device. Through the noise test, it is found that with the increase of the radiation fluence, the current noise power spectral density gradually increases. When the fluence reaches 1×1010 ions/cm2, the defect density increases to 3.19×1018 cm–3·eV–1, and the Hooge parameter increases after having been irradiated by heavy ions. We believe that the radiation leads to the defect density and parasitic series resistance of AlGaN/GaN HEMT device to increases, resulting in larger Hooge parameters. Through analyzing the variation of the normalized power spectral density of the drain current noise with bias voltage, it is found that the defects caused by heavy ion radiation will cause the parasitic series resistance to increase.
First-principles calculations of structural and magnetic properties of SmCo3 alloys doped with transition metal elements
Authors: Yan Zhi , Fang Cheng , Wang Fang , Xu Xiao-Hong ,   School of Chemistry and Materials Science & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan 030031, China
Published: November 2023

Among the spectra of rare-earth permanent magnetic materials, the Sm-Co-based alloys stand out with their excellent magnetic properties in high-temperature environments. However, the practical applications of these alloys in high-temperature settings face constraints due to their comparatively lower saturation magnetization and structural stability. In this study, Fe, Ni, Cu, and Zr are used as representative transition metal elements to investigate the effects of doping elements on the structural stability, magnetic properties, and electronic structure of SmCo3 alloy by first-principles calculations. The findings indicate that the doping of elements Ni, Cu, and Fe contributes positively to enhancing the structural stability of the SmCo3, while the introduction of Zr element has an adverse effect. Magnetic property calculations reveal that the incorporation of non-magnetic elements leads the total magnetic moment of the SmCo3 to decrease to a certain extent, whereas the introduction of magnetic elements can enhance the total magnetic moment. Notably, not all doped magnetic elements in the SmCo3 result in an increasing total magnetic moment. The underlying microscopic mechanisms are elucidated through electronic structure analysis. Finally, it is screened out that the transition element Fe is beneficial to improving the magnetic properties and structural stability of SmCo3, and the doping concentration (atomic percentage) in its unit cell ranges from 0 to 22.22%, the optimal doping concentration (atomic percentage) is predicted to be 18.52%.
Robust, fast and accurate mapping of diffusional mean kurtosis
Authors: Farquhar Megan E , Yang Qianqian , Vegh Viktor
Published: November 2023

Diffusional kurtosis imaging (DKI) is a methodology for measuring the extent of non-Gaussian diffusion in biological tissue, which has shown great promise in clinical diagnosis, treatment planning, and monitoring of many neurological diseases and disorders. However, robust, fast, and accurate estimation of kurtosis from clinically feasible data acquisitions remains a challenge. In this study, we first outline a new accurate approach of estimating mean kurtosis via the sub-diffusion mathematical framework. Crucially, this extension of the conventional DKI overcomes the limitation on the maximum b-value of the latter. Kurtosis and diffusivity can now be simply computed as functions of the sub-diffusion model parameters. Second, we propose a new fast and robust fitting procedure to estimate the sub-diffusion model parameters using two diffusion times without increasing acquisition time as for the conventional DKI. Third, our sub-diffusion-based kurtosis mapping method is evaluated using both simulations and the Connectome 1.0 human brain data. Exquisite tissue contrast is achieved even when the diffusion encoded data is collected in only minutes. In summary, our findings suggest robust, fast, and accurate estimation of mean kurtosis can be realised within a clinically feasible diffusion-weighted magnetic resonance imaging data acquisition time.
Non-Hebbian plasticity transforms transient experiences into lasting memories
Authors: Faress Islam , Khalil Valentina , Hou Wen-Hsien , Moreno Andrea , Andersen Niels , Fonseca Rosalina , Piriz Joaquin , Capogna Marco , Nabavi Sadegh
Published: November 2023

The dominant models of learning and memory, such as Hebbian plasticity, propose that experiences are transformed into memories through input-specific synaptic plasticity at the time of learning. However, synaptic plasticity is neither strictly input-specific nor restricted to the time of its induction. The impact of such forms of non-Hebbian plasticity on memory has been difficult to test, and hence poorly understood. Here, we demonstrate that synaptic manipulations can deviate from the Hebbian model of learning, yet produce a lasting memory. First, we established a weak associative conditioning protocol in mice, where optogenetic stimulation of sensory thalamic input to the amygdala was paired with a footshock, but no detectable memory was formed. However, when the same input was potentiated minutes before or after, or even 24 hr later, the associative experience was converted into a lasting memory. Importantly, potentiating an independent input to the amygdala minutes but not 24 hr after the pairing produced a lasting memory. Thus, our findings suggest that the process of transformation of a transient experience into a memory is neither restricted to the time of the experience nor to the synapses triggered by it; instead, it can be influenced by past and future events.
Sympathetic motor neuron dysfunction is a missing link in age-associated sympathetic overactivity
Authors: de La Cruz Lizbeth , Bui Derek , Moreno Claudia M , Vivas Oscar
Published: November 2023

Overactivity of the sympathetic nervous system is a hallmark of aging. The cellular mechanisms behind this overactivity remain poorly understood, with most attention paid to likely central nervous system components. In this work, we hypothesized that aging also affects the function of motor neurons in the peripheral sympathetic ganglia. To test this hypothesis, we compared the electrophysiological responses and ion-channel activity of neurons isolated from the superior cervical ganglia of young (12 weeks), middle-aged (64 weeks), and old (115 weeks) mice. These approaches showed that aging does impact the intrinsic properties of sympathetic motor neurons, increasing spontaneous and evoked firing responses. A reduction of M current emerged as a major contributor to age-related hyperexcitability. Thus, it is essential to consider the effect of aging on motor components of the sympathetic reflex as a crucial part of the mechanism involved in sympathetic overactivity.
Circuit-based intervention corrects excessive dentate gyrus output in the fragile X mouse model
Authors: Deng Pan-Yue , Kumar Ajeet , Cavalli Valeria , Klyachko Vitaly A
Published: November 2023

Abnormal cellular and circuit excitability is believed to drive many core phenotypes in fragile X syndrome (FXS). The dentate gyrus is a brain area performing critical computations essential for learning and memory. However, little is known about dentate circuit defects and their mechanisms in FXS. Understanding dentate circuit dysfunction in FXS has been complicated by the presence of two types of excitatory neurons, the granule cells and mossy cells. Here we report that loss of FMRP markedly decreased excitability of dentate mossy cells, a change opposite to all other known excitability defects in excitatory neurons in FXS. This mossy cell hypo-excitability is caused by increased Kv7 function in Fmr1 knockout (KO) mice. By reducing the excitatory drive onto local hilar interneurons, hypo-excitability of mossy cells results in increased excitation/inhibition ratio in granule cells and thus paradoxically leads to excessive dentate output. Circuit-wide inhibition of Kv7 channels in Fmr1 KO mice increases inhibitory drive onto granule cells and normalizes the dentate output in response to physiologically relevant theta–gamma coupling stimulation. Our study suggests that circuit-based interventions may provide a promising strategy in this disorder to bypass irreconcilable excitability defects in different cell types and restore their pathophysiological consequences at the circuit level.
Modification of a commercial activated carbon with nitrogen and boron : hydrogen storage application
Authors:   , Morandé Thompson Arturo Ignacio
Published: November 2023

En esta investigación, se estudió y modificó un carbón activado comercial con una superficie específica (SSA) de 1678 m2/g con la finalidad de almacenar hidrógeno mediante la adsorción física a 77 K. Para este propósito, se consideraron diferentes métodos de modificación. Se llevaron a cabo tratamientos con helio a 200 y 400 °C para reducir la concentración de grupos funcionales oxigenados en la superficie de la muestra original; se realizaron modificaciones con amoníaco a 400, 500 y 600 °C para producir muestras dopadas con nitrógeno; y se realizaron impregnaciones con bórax decahidratado para dopar las muestras con boro. Se produjeron un total de 13 muestras mediante estos tres métodos de modificación, los que fueron aplicados en diferentes órdenes. Las muestras se analizaron y caracterizaron mediante isotermas de adsorción/desorción de nitrógeno, descomposiciones programadas por temperatura, espectroscopías fotoelectrónicas de rayos X e isotermas de adsorción de hidrógeno. Adicionalmente, se aplicó el modelo de adsorción de Dubinin-Astakhov para extrapolar los datos experimentales de adsorción de hidrógeno hasta una presión de 100 bares, y se desarrolló un modelo de teoría del funcional de la densidad para analizar el efecto de las funcionalidades nitrogenadas en la adsorción de hidrógeno. En base a los resultados, se concluyó que el mejor procedimiento de modificación fue el tratamiento con helio a 400 °C seguido de un tratamiento con amoníaco a 500 °C, lo que aumentó la adsorción de hidrógeno desde un 1,98% a un 2,34% en peso. Además, todas las muestras dopadas con boro redujeron su adsorción de hidrógeno debido a la pérdida de superficie específica, aunque aumentó la adsorción por unidad de área, es decir, % en peso/SSA.
Sincronización de visitas regulares para resolver el problema de ruteo con inventario de largo plazo
Authors:   , Avalos Cembrano Andrés Emilio
Published: November 2023

En la planificación de cadenas de abastecimiento, existen situaciones que requieren mantener una red de inventarios distribuidos en el espacio. Este “problema de ruteo de inventarios” (IRP), en que normalmente se busca balancear los costos de inventario y ruteo de los vehículos, implica definir cuándo reponer cada bodega de la red y las rutas a efectuar con los vehículos de reabastecimiento. Por otra parte, en la literatura reciente se ha observado que los clientes valoran ciertos niveles de consistencia en los despachos, particularmente en la regularidad con la que son visitados. Frente a esto, nace la motivación de estudiar cómo planificar despachos regulares, y cuál es el costo que implica imponer dicha regularidad. Para abordar estas preguntas se formuló el “problema de ruteo regular con inventario” (RIRP) que modela las decisiones en un horizonte infinito, pero cuya solución es altamente compleja debido a la no linealidad del modelo. Para poder abordar el problema se estudió el fenómeno de sincronización de frecuencias, lo que permitió generar indicadores de la conveniencia de coincidir las visitas de ciertos clientes. A partir de dicho estudio se observó que el problema posee clientes "líderes" que imponen su frecuencia ideal de visita, y clientes "seguidores" que adaptan su frecuencia ideal en el plan óptimo. El estudio también permitió obtener expresiones para estimar el efecto de sincronizar clientes, las que fueron utilizadas para definir la heurística “M-Sync” que resuelve el RIRP a través de una exploración inteligente del espacio de soluciones factibles. Los experimentos computacionales permitieron observar que imponer regularidad en las visitas aumenta los costos de la planificación de largo plazo en un 0.48% promedio. Además, M-Sync logra igualar la solución del RIRP obtenida por un modelo exacto en el 40% de las instancias estudiadas y presenta diferencias menores al 4%.
Development and testing of LoRa Technology for satellite communications
Authors:   , Dunford Pabst Antonia Kate
Published: November 2023

Dada la topografía particular de Chile, hay muchas áreas rurales/remotas sin conectividad IoT porque es demasiado costoso instalar la infraestructura necesaria para una red terrestre. De este modo, para establecer un país verdaderamente conectado, las redes terrestres deben complementarse con redes satelitales. LoRa es una tecnología prometedora para conseguir este objetivo y está recién empezando a ser testeada para comunicación satelital alrededor del mundo. Por lo tanto, el objetivo principal de esta tesis es desarrollar un prototipo de comunicación inalámbrica de bajo costo con LoRa y probarlo para evaluar su viabilidad con tal de tener una red satelital de IoT en Chile. Para ello, se evaluaron diferentes órbitas, se propusieron diseños de enlaces de comunicación y se construyeron los nodos del prototipo. Luego, se probó la comunicación Tierra-espacio con la construcción de una estación terrestre que puede recibir paquetes de datos de satélites en órbita. El precio final de un dispositivo (nodo + antena) resultó ser ∼ $60000 CLP (US$ 70). Se concluyo que la órbita óptima (considerando cobertura y altitud) es una órbita geosíncrona, pero en la práctica las órbitas bajas (LEO) son la opción más factible. Los parámetros de diseño de LoRa seleccionados para los enlaces de comunicación son SF = 12, BW = 125 kHz y CR = 1 para la órbita geosíncrona y SF = 9, BW = 125 kHz y CR = 1 para LEO. Los nodos desarrollados funcionaron con éxito en pruebas de comunicación punto-a-punto y la estación terrestre estuvo operativa durante 18 días en un sector urbano y durante 29 días en un sector remoto. Se recibieron correctamente un total de 252 paquetes y no se requirió ningún mecanismo de seguimiento para la antena. Con todo esto, se puede concluir que es posible contar con una red satelital de IoT económicamente asequible en Chile, dado que está demostrado que los satélites en LEO pueden comunicarse exitósamente con nodos colocados tanto en áreas urbanas como remotas, con un alcance máximo estimado de aprox. 1200 km usando 500 mW de potencia de transmisión.