Major Changes Research Articles

Meiobenthos and ocean acidification: Effects on meiobenthic communities inhabiting Mediterranean cold shallow CO2-vents

Ocean acidification is causing major changes in marine ecosystems, with varying levels of impact, depending both on the habitat and the studied organisms. Here, we investigated for the first time the meiobenthos and nematode fauna inhabiting the sediments around Castello Aragonese (Ischia, Italy), characterized by variable pH values due to coastal volcanic CO2 venting. In this scenario, nematode functional diversity changed according to different pH levels and grain size: maturity index was higher at most acidic stations and trophic composition spanned from the dominance of predators in the acidic stations, to the high abundance of non-selective deposit feeders and epistrate feeders in the ambient-pH stations. Overall, the present study revealed a relatively high tolerance of meiobenthos and nematodes to lower pH conditions. However, an in-depth analysis of nematode fauna showed differences in their assemblages at different pH levels with few nematode genera rather adapted to the extreme environmental conditions at the acidic stations.

Policies, projections, and the social cost of carbon: Results from the DICE-2023 model

The present study examines the assumptions, modeling structure, and results of DICE-2023, the revised Dynamic Integrated Model of Climate and the Economy (DICE), updated to 2023. The revision contains major changes in the treatment of risk, the carbon and climate modules, the treatment of nonindustrial greenhouse gases, discount rates, as well as updates on all the major components. Noteworthy changes are a significant reduction in the target for the optimal (cost-beneficial) temperature path, a lower cost of reaching the 2 °C target, an analysis of the impact of the Paris Accord, and a major increase in the estimated social cost of carbon.

Ocena wpływu ustawy o ograniczaniu inflacji Stanów Zjednoczonych z 2022 r. na międzynarodowych producentów samochodów na przykładzie Volkswagena

The Inflation Reduction Act, passed by the U.S. Congress in 2022, is a major climate change investment plan that allocates nearly half a trillion dollars for climate initiatives and health care. A key aspect of the Inflation Reduction Act is subsidizing electric vehicles based on certain criteria that call for national production in particular. Only nine automakers, including one international one, namely Volkswagen, made it onto the list of carmakers approved for the subsidy. The exclusion of foreign manufacturers caused controversy. Volkswagen’s inclusion gave it a massive competitive advantage. This case study examines the impact of the Inflation Reduction Act on international business related to the automotive industry, specifically Volkswagen, using a SWOT analysis. The eligibility criteria for electric vehicle subsidies are analyzed, showing the focus on U.S. production and components. The SWOT analysis examines Volkswagen’s strengths, weaknesses, opportunities, and threats considering the IRA.

Performance test results of a helium Dewar for the Resolve instrument onboard the XRISM

The X-ray imaging and spectroscopy mission (XRISM) is an X-ray astronomy satellite developed by the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) to explore the evolution of the universe and its physical phenomena as the replacement for ASTRO-H. One of the primary scientific instruments of the XRISM is the Resolve, which utilizes an X-ray microcalorimeter array. This detector array is required to be cooled down to 50 mK using a complex cryogenic system with a multistage adiabatic demagnetization refrigerator (ADR) developed by NASA and a cryogenic system developed by Sumitomo Heavy Industries, Ltd. (SHI). The cryogenic system is required to cool the heat sink of the ADR to a temperature below 1.5 K in orbit for at least 3 years. To meet the specific requirements, we developed a hybrid cryogenic system consisting of a liquid helium tank, a 4K Joule–Thomson cooler, and two two-stage Stirling coolers. As a result, the specific requirements were verified by ground tests. This paper describes the design, including the major changes from ASTRO-H, fabrication, and results of the ground tests of the helium Dewar of the Resolve instrument.

The ECB’s Monetary Policy Review: A Post-Keynesian Twist?

ABSTRACT In 2021, the European Central Bank (ECB) decided to adjust its monetary policy strategy. Three major changes were initiated: the main objective was reformulated, but also the structure of the institution’s analyses of the economic situation and how it will communicate in the future was adjusted. Can these changes be considered as being based on a Post-Keynesian view or do they still follow the ‘New Consensus’ model largely based on standard neo-classical theory? Our main conclusion will be that the adjustments made by the ECB are not necessarily based on Post-Keynesian analysis. To justify this statement, we have developed what we consider the basic elements of a Post-Keynesian monetary policy, then we analysed what a Post-Keynesian monetary rule could be as well as the monetary policy instruments used by the ECB. Subsequently we looked at the strategy changes made by the ECB from a Post-Keynesian point of view and concluded that some of these changes can be considered as being close to Post-Keynesian theory, but other facts explain why the ECB’s monetary policy is still close to the ‘New Consensus’ model.

Biological effects of diesel exhaust inhalation. III cardiovascular function

Objective Inhalation of diesel exhaust (DE) has been shown to be an occupational hazard in the transportation, mining, and gas and oil industries. DE also contributes to air pollution, and therefore, is a health hazard to the general public. Because of its effects on human health, changes have been made to diesel engines to reduce both the amounts of particulate matter and volatile fumes they generate. The goal of the current study was to examine the effects of inhalation of diesel exhaust. Materials and Methods The study presented here specifically examines the effects of exposure to 0.2 and 1.0 mg/m3 DE or filtered air (6h/d for 4 d) on measures of peripheral and cardio-vascular function, and biomarkers of heart and kidney dysfunction in male rats. A Tier 2 engine used in oil and gas fracking operations was used to generate the diesel exhaust. Results Exposure to 0.2 mg/m3 DE resulted in an increase in blood pressure 1d following the last exposure, and increases in dobutamine-induced cardiac output and stroke volume 1 and 27d after exposure. Changes in peripheral vascular responses to norepinephrine and acetylcholine were minimal as were changes in transcript expression in the heart and kidney. Exposure to 1.0 mg/m3 DE did not result in major changes in blood pressure, measures of cardiac function, peripheral vascular function or transcript expression. Discussion and Conclusions Based on the results of this study, we suggest that exposure to DE generated by a Tier 2 compliant diesel engine generates acute effects on biomarkers indicative of cardiovascular dysfunction. Recovery occurs quickly with most measures of vascular/cardiovascular function returning to baseline levels by 7d following exposure.

Formulation and Evaluation of Hard Lozenges by Using Garlic Tincture

Background:: Lozenges are one of the more well-liked and inventive oral confectionery products in the market. The lozenges also act as solid medications that are flavored, sweetened, and meant to be sucked into the mouth/pharynx or held over that cavity. Garlic contains anti-microbial agents which help to reduce the impact of cough and reduce it. Aims:: The goal of the current research is to formulate and investigate herbal lozenges by using garlic tinctures with their antimicrobial action to cure the infection caused by microbes Methods:: Hard lozenges were prepared by Heating and congealing techniques and statistical analysis was done by using one sample chi-square test (IBM SPSS version 20). Results:: Hard lozenges were formulated by using garlic tinctures with minimum excipients. According to ICH recommendations, stability experiments were conducted. According to the stability investigations, there were no major changes noticed during the period after the one-month stability test. The antimicrobial activity was studied under different time intervals after 8-72 hours. The inhibition zone value for the test sample was found to be 0.1-0.5 mm and for the standard sample was noticed from 0.5-0.8 mm, respectively. The statistical test outcome revealed, no remarkable difference shown between the prepared and the marketed formulation (p>0.05). Conclusion:: From the present work, it was concluded that the prepared lozenges have similar result with minimum ingredients as compared to the marketed formulation (Tulsi-ginger lozenges). Hence, the formulation, testing, and antimicrobial activity for oral use in garlic lozenges were effective.

Review of Asset Management Practice in Indonesian State-Owned Enterprise

This study examines Indonesian State-Owned Enterprises (SOEs) asset management methods, problems, and financial and operational performance effects. The report synthesizes case studies and academic research on how large organizations manage their huge and diverse asset portfolios and how governance, regulatory frameworks, and human resource practices affect their effectiveness. The research begins with case studies of talent management innovations from big Indonesian SOEs. These cases show how proactive human resource approaches can boost company commitment and reduce turnover, improving asset management efficiency. According to the research, governance and legal frameworks influence asset management techniques. Studies show that corporate governance quality affects SOE operational performance. The paper explores how reforms and legislation affect state asset management, highlighting the major changes in SOE governance and legal frameworks, particularly after economic and political reforms. Asset management difficulties for Indonesian SOEs include managing large and diverse asset portfolios, integrating modern management frameworks, and optimizing state asset revenue. According to the study, comprehensive asset management systems, governance transparency, and professional management can address these difficulties. The research examines how asset management strategies affect Indonesian SOE profitability, corporate governance, and performance measures. Strategic asset management boosts financial performance, especially profitability. SOE profitability is greatly affected by current asset and liability management. The study offers advice to Indonesian SOEs and policymakers. Enhancing financial and operational performance requires comprehensive asset management, governance changes, and strategic innovation. These efforts boost Indonesia's economy, demonstrating the importance of asset management in SOE performance.

How Do Arable Crop Farmers’ Adapt to Climate Change? New Evidence from Nigeria

In Nigeria, climate change is not a new phenomenon and arable crop production is vulnerable to climate change. Arable crop farmers have always responded to climate change with local strategies believed to be climate-smart. Arable crop farmers' knowledge of climate change is an important step in understanding any action to be taken to reduce its effect. However, empirical studies on the link between climate change and crop farmers’ adaptation strategies are still relatively scanty in the area. This presents a dearth in research. Therefore, our paper examined how arable crop farmers adapt to climate change using cross-sectional data obtained through a structured focused group discussion and questionnaire from 120 arable farmers across critical farming communities in Imo State, Nigeria. We utilized multistage and purposive sampling procedure in the selection of arable crop farmers. The reason we utilized purposive sampling procedure was to select areas with high intensity of arable crop farmers and farming. Data collected was analyzed using descriptive statistical tools and mean (x̄) score analysis. Our result shows that the mean age was 42.00 years. Greater proportions (73.00%) were female. The average farm size was 1.45 hectares. Vegetables (100.00%), maize (99.17%), cassava (98.33%) and rice (96.67%) were among the crops produced in the area. The result confirmed the incidence of climate change in the area and farmers perceived rightly the direction of the change, which includes declining crop yields (x̄ = 3.00; σ = 0.50), increased in new pests and diseases infestation (x̄= 2.88; σ = 0.58); unstable decrease and increase in temperature and rainfall (x̄=3.63, σ = 0.83) among others. Our study further shows that the major climate change adaptation measures farmers practiced were diversification of livelihood (99.17%) and changing planting/harvesting dates (97.50%). Farmers identified inadequate information (99.17) and inadequate climate change adaptation fund (98.33%) among others as the barriers they faced in adapting to climate change in the area. We recommend that, since arable crop farmers are members of cooperatives, they are encouraged to take advantage of their strength to collectively project a common demand in obtaining funds and other necessary inputs in adapting to climate change in the area. Finally, our study also suggests that the agricultural extension service system should be strengthened so as to provide farmers with stable and right early warning signs which will be critical in minimizing risks of climatic threats in the area.

Efficacy and safety of everolimus plus exemestane in patients with hormone receptor-positive, HER-2-negative advanced breast cancer: Results from the open-label, multicentre, non-interventional BRAWO study.

BRAWO, a real-world study, assessed the efficacy, quality of life (QoL) and safety of EVE + EXE in postmenopausal women with HR+/HER2- advanced breast cancer (ABC) in routine clinical practice. Postmenopausal women with HR+/HER2-ABC with recurrence or progression after a NSAI were included. Primary Observation parameters included the evaluation of the effectiveness of EVE + EXE. A multivariate-analysis using Cox proportional hazard model was built to identify predictors of progression. Overall, 2100 patients were enrolled (August 2012-December 2017); 2074 were evaluable for efficacy and safety analyses. Majority of patients (60.6%) received EVE + EXE as first (28.7%) or second-line (31.9%) therapy. Visceral metastases were present in 54.1% patients. Median progression-free survival (mPFS) reported as 6.6 months (95%CI: 6.3-7.0). Multivariate-analysis in a subset of patients (n = 1837) found higher body mass index (BMI) and non-visceral metastases to be independent predictors of favorable PFS. Patients with a BMI of 20 to <25 had a mPFS of 6.0 (95%CI: 5.4-6.4) and those with a BMI ≥30 had mPFS of 8.5 (95%CI: 6.9-9.9). 41.2% patients achieved stable disease and 7.3% partial response. No major changes were observed QoL; 86.4% patients received stomatitis prophylaxis and 41.4% experienced EVE related AEs of stomatitis, mainly low grade. AEs occurred in 91.2% of patients, of which stomatitis (42.6%) and fatigue (19.8%) were most frequent. The BRAWO study provides real-world evidence of efficacy and safety of EVE + EXE in patients with HR+, HER2- ABC. A high BMI and the absence of visceral metastases were independent predictors of PFS in this cohort of patients.

Attitudes toward the American Cancer Society's 2020 cervical cancer screening guidelines: A qualitative study of a national sample of US clinicians.

The 2020 American Cancer Society (ACS) guidelines are the most recent national guidelines for cervical cancer screening. These guidelines propose two major changes from current practice: initiating screening at age 25 years and using primary human papillomavirus (HPV) testing. Adoption of guidelines often occurs slowly, and therefore understanding clinician attitudes is important to facilitate practice change. Interviews with a national sample of clinicians who perform cervical cancer screening in a variety of settings explored attitudes toward the two major changes from the 2020 ACS cervical cancer screening guidelines. Clinicians participated in 30- to 60-min interviews exploring their attitudes toward various aspects of cervical cancer screening. Qualitative analysis was performed. Seventy clinicians participated from across the United States. Few respondents were initiating screening at age 25 years, and none were using primary HPV testing. However, over half would be willing to adopt these practices if supported by scientific evidence and recommended by professional medical organizations. Barriers to adoption included the lack of endorsement by professional societies, lack of laboratory availability and insurance coverage, limited autonomy within large health care systems, and concerns related to missed disease. Few clinicians have adopted screening initiation or primary HPV testing, as recommended by the 2020 ACS guidelines, but over half were open to adopting these changes. Implementation may be facilitated via professional organization endorsement, clinician education, and laboratory, health care system, and insurance support. In 2020, the American Cancer Society (ACS) released updated guidelines for cervical cancer screening. The main changes to current practices were to initiate screening at age 25 years instead of age 21 years and to screen using primary human papillomavirus (HPV) testing rather than cytology alone or in combination with HPV testing. We performed in-depth interviews with 70 obstetrics and gynecology, family medicine, and internal medicine physicians and advanced practice providers about their attitudes toward these guidelines. Few clinicians are following the 2020 ACS guidelines, but over half were open to changing practice if the changes were supported by evidence and recommended by professional medicalorganizations. Barriers to adoption included the lack of endorsement by professional medical organizations, logistical issues, and concerns about missed disease.

Molecular GBM versus Histopathological GBM: Radiology-Pathology-Genetic Correlation and the New WHO 2021 Definition of Glioblastoma.

Given the recent advances in molecular pathogenesis of tumors, with better correlation with tumor behavior and prognosis, major changes were made to the new 2021 WHO (CNS5) classification of CNS tumors, including updated criteria for diagnosis of glioblastoma. Diagnosis of GBM now requires absence of isocitrate dehydrogenase and histone 3 mutations (IDH-wildtype and H3-wildtype) as the basic cornerstone, with elimination of the IDH-mutated category. The requirements for diagnosis were conventionally histopathological, based on the presence of pathognomonic features such as microvascular proliferation and necrosis. However, even if these histological features are absent, many lower grade (WHO grade 2/3) diffuse astrocytic gliomas behave clinically similar to GBM (grade 4). The 2021 WHO classification introduced new molecular criteria that can be used to upgrade the diagnosis of such histologically lower-grade, IDH-wildtype, astrocytomas to GBM. The three molecular criteria include: concurrent gain of whole chromosome 7 and loss of whole chromosome 10 (+7/-10); TERT promoter mutation; epidermal growth factor receptor (EGFR) amplification. Given these changes, it is now strongly recommended to have molecular analysis of WHO grade 2/3 diffuse astrocytic, IDH-wildtype, gliomas in adult patients, as identification of any of the above mutations allows for upgrading the tumor to WHO grade 4 ("molecular GBM") with important prognostic implications. Despite at an early stage, there is active ongoing research on the unique MRI features of molecular GBM. This paper highlights the differences between "molecular" and "histopathological" GBM, with the aim of providing a basic understanding about these changes.ABBREVIATIONS: GBM=Glioblastoma; TERT=telomerase reverse transcriptase; EGFR=epidermal growth factor receptor; MGMT= methylguanine-DNA methyltransferase; NGS= next-generation sequencing; IDH= isocitrate dehydrogenase.

The effect of landfast sea ice buttressing on ice dynamic speedup in the Larsen B embayment, Antarctica

Abstract. We observe the evacuation of 11-year-old landfast sea ice in the Larsen B embayment on the East Antarctic Peninsula in January 2022, which was in part triggered by warm atmospheric conditions and strong offshore winds. This evacuation of sea ice was closely followed by major changes in the calving behaviour and dynamics of a subset of the ocean-terminating glaciers in the region. We show using satellite measurements that, following a decade of gradual slow-down, Hektoria, Green, and Crane glaciers sped up by approximately 20 %–50 % between February and the end of 2022, each increasing in speed by more than 100 m a−1. Circumstantially, this is attributable to their transition into tidewater glaciers following the loss of their ice shelves after the landfast sea ice evacuation. However, a question remains as to whether the landfast sea ice could have influenced the dynamics of these glaciers, or the stability of their ice shelves, through a buttressing effect akin to that of confined ice shelves on grounded ice streams. We show, with a series of diagnostic modelling experiments, that direct landfast sea ice buttressing had a negligible impact on the dynamics of the grounded ice streams. Furthermore, we suggest that the loss of landfast sea ice buttressing could have impacted the dynamics of the rheologically weak ice shelves, in turn diminishing their stability over time; however, the accompanying shifts in the distributions of resistive stress within the ice shelves would have been minor. This indicates that this loss of buttressing by landfast sea ice is likely to have been a secondary process in the ice shelf disaggregation compared to, for example, increased ocean swell or the drivers of the initial landfast sea ice disintegration.

From The New Order To The Benevolent Event – Making Children’s Education Compulsory In The Ottoman Empire, 1808 – 1824

Sultan Mahmud II’s era witnessed gradual transition of the centuries old classical Ottoman education system that is controlled by the ulama into a state administration by the announcement of an imperial decree in 1824. Although this major change was historically the third in the Europe, somehow has not been a specific topic for an academic research so far. In fact, as the documents from the Ottoman archives confirm, Sultan’s efforts concerning children’s basic education began almost a decade earlier. He was concerned about deteriorating quality of the education system. Based on the primary sources, this study aims to portray historic background and the official transfer of children’s education under state control. This decree did not only make children’s education compulsory but also displayed families bad habit of letting little children to work instead of sending them to schools. According to the imperial decree, children started working at a very early age and did not learn basics of their religion and when they grow up, they did not go and educate themselves either. Sultan instructed authorities to prevent child labour and assure children attended schools learning basics of their religion. In effect, children’s education became collective responsibility of not only the families but also imams, school teachers, neighbourhood administrators and judges.

CDC-like kinase 3 deficiency aggravates hypoxia-induced cardiomyocyte apoptosis through AKT signaling pathway.

Hypoxia-induced cardiomyocyte apoptosis is one major pathological change of acute myocardial infarction (AMI), but the underlying mechanism remains unexplored. CDC-like kinase 3 (CLK3) plays crucial roles in cell proliferation, migration and invasion, and nucleotide metabolism, however, the role of CLK3 in AMI, especially hypoxia-induced apoptosis, is largely unknown. The expression of CLK3 was elevated in mouse myocardial infarction (MI) models and neonatal rat ventricular myocytes (NRVMs) under hypoxia. Furthermore, CLK3 knockdown significantly promoted apoptosis and inhibited NRVM survival, while CLK3 overexpression promoted NRVM survival and inhibited apoptosis under hypoxic conditions. Mechanistically, CLK3 regulated the phosphorylation status of AKT, a key player in the regulation of apoptosis. Furthermore, overexpression of AKT rescued hypoxia-induced apoptosis in NRVMs caused by CLK3 deficiency. Taken together, CLK3 deficiency promotes hypoxia-induced cardiomyocyte apoptosis through AKT signaling pathway.

Feeling good

A post-pandemic training programme that focuses on wellbeing has resulted in major changes at settings. By Annette Rawstrone

121 Unraveling the biology of bovine conceptus elongation

Abstract The establishment of pregnancy is a well-regulated process that involves the development of a viable blastocyst, conceptus elongation, maternal recognition of pregnancy, implantation, and the onset of placentation. Pregnancy loss is a major factor limiting reproductive efficiency in livestock species. In cattle, most embryonic losses occur during the first month of gestation. The genetic and epigenetic regulation of embryonic and placental development in ruminants is still poorly understood. To investigate the transcriptome profile of the bovine conceptus during elongation, Angus heifers (n = 8) were superovulated and bred using semen from a proven high-fertility Bos indicus sire. Heifers were flushed on d 14 of gestation using a standard nonsurgical flushing technique. Recovered conceptuses were individually photographed and snap-frozen for total RNA extraction and bulk mRNA sequencing. Recovered conceptuses were classified based on size into ovoid (0.2 – 5mm; n = 6), tubular (&amp;lt;15 mm; n = 7), or filamentous (&amp;gt;16 mm; n = 7). Differentially expressed genes (DEG: FDR &amp;lt; 0.05) were determined using DESeq2 analysis and were functionally annotated using DAVID. The most pronounced transcriptomic changes were identified between the ovoid and tubular stages, with 5,937 DEGs (2,913 upregulated and 3,024 downregulated) and affected pathways were primarily involved in ribosome assembly and rRNA processing. There were 3,966 DEGs (2,069 upregulated and 1,897 downregulated) between the ovoid and filamentous stages, and the most significant pathways were involved in protein translation, embryonic development, and cell cycle. The transition between tubular to filamentous presented 1,435 DEGs (775 upregulated and 660 downregulated) and significant pathways were involved in protein degradation, cell division, cell cycle, protein stabilization, and mRNA splicing. Our findings indicate that the greatest alterations in the transcriptome occur precisely at the initiation of elongation, suggesting that the bovine conceptus undergoes major structural changes at the outset of this process. This major shift in gene expression is presumed to be necessary to support the subsequent exponential growth phase of elongation, required for maternal recognition of pregnancy.

Ancient Genomes From Bronze Age Remains Reveal Deep Diversity and Recent Adaptive Episodes for Human Oral Pathobionts.

Ancient microbial genomes can illuminate pathobiont evolution across millenia, with teeth providing a rich substrate. However, the characterization of prehistoric oral pathobiont diversity is limited. In Europe, only preagricultural genomes have been subject to phylogenetic analysis, with none compared to more recent archaeological periods. Here, we report well-preserved microbiomes from two 4,000-year-old teeth from an Irish limestone cave. These contained bacteria implicated in periodontitis, as well as Streptococcus mutans, the major cause of caries and rare in the ancient genomic record. Despite deriving from the same individual, these teeth produced divergent Tannerella forsythia genomes, indicating higher levels of strain diversity in prehistoric populations. We find evidence of microbiome dysbiosis, with a disproportionate quantity of S. mutans sequences relative to other oral streptococci. This high abundance allowed for metagenomic assembly, resulting in its first reported ancient genome. Phylogenetic analysis indicates major postmedieval population expansions for both species, highlighting the inordinate impact of recent dietary changes. In T. forsythia, this expansion is associated with the replacement of older lineages, possibly reflecting a genome-wide selective sweep. Accordingly, we see dramatic changes in T. forsythia's virulence repertoire across this period. S. mutans shows a contrasting pattern, with deeply divergent lineages persisting in modern populations. This may be due to its highly recombining nature, allowing for maintenance of diversity through selective episodes. Nonetheless, an explosion in recent coalescences and significantly shorter branch lengths separating bacteriocin-carrying strains indicate major changes in S. mutans demography and function coinciding with sugar popularization during the industrial period.

The impact of new media sites on the culture of dialogue for young people

The research paper seeks to identify the role of social media networks in supporting the culture of dialogue among Arab youth. Contemporary society is experiencing major transformations in the field of communication and media, which in recent years have led to major changes in the methods of producing, distributing, and receiving information This study is concerned with youth, as they are considered the beating heart of society. They are the leaders of the future. A society rich in its youth is a prosperous society, unlike a society poor in its youth, which is destined for disintegration and collapse. The study is also concerned with the importance of the Internet, its mechanisms, and the seriousness of its role at the present time. The importance of the culture of dialogue has also emerged, which calls for studying the culture of dialogue on social media networks in Arab societies, to determine the nature of the use of these networks to benefit from their wide smart means of dissemination, and to activate the culture of dialogue in a positive way and to conduct more studies on its use of these networks to monitor the potential effects of As a result of this use on the psychological and social level specifically

Study of synchronous RF pulsing in dual frequency capacitively coupled plasma

Low-pressure multi-frequency capacitively coupled plasmas (CCPs) are used for numerous etch and deposition applications in the semiconductor industry. Pulsing of the radio-frequency (RF) sources enables control of neutral and charged species in the plasma on a millisecond timescale. The synchronous (i.e. simultaneous, in-phase) pulsing of both power sources in a dual frequency CCP is examined in this article. Due to the low gas pressure, modeling has been done using the electrostatic particle-in-cell/Monte Carlo collision method. The objective of this work is to investigate the sensitivity of the plasma properties to small changes in timing during synchronous pulsing of the two RF sources. It is demonstrated that small deviations in the on and off times of the two RF sources can lead to major changes in the plasma characteristics. This high sensitivity is of concern for process repeatability but can be utilized to enable better control of the dynamics of plasma-surface interaction. In the simulations, the pulsing parameters (on and off times and ramp rates) are varied and the temporal evolution of plasma characteristics such as electron density (ne ), species current at the electrode, and electron temperature are examined. It is demonstrated that if the low-frequency (LF) source is turned off a few μs before (or after) the high-frequency source, ne during the off-state is significantly higher (or lower) due to the frequency coupling effect. Similarly, turning on the LF source with a small delay results in a sharp increase in the plasma density when the RF sources are turned on.