A ground-based experimental test program to duplicate and study the spacecraft glow phenomenon

The use of a plasma device, the Advanced Concepts Torus-I, for producing atoms and molecules to study spacecraft glow mechanisms is discussed. A biased metal plate, located in the plasma edge, is used to accelerate and neutralize plasma ions, thus generating a neutral beam with a flux approx. 5 x 10 to the 14th power/sq cm/sec at the end of a drift tube. Our initial experiments are to produce a 10 eV molecular and atomic nitrogen beam directed onto material targets. Photon emission in the spectral range 2000 to 9000 A from excited species formed on the target surface will be investigated

Groundbased studies of spacecraft glow and erosion caused by impact of oxygen and nitrogen beams

To simulate surface reactions in the space environment a ground-based facility was developed that produces a very high flux 10(14) to 10(16)/sq cm/s of low energy (2 to 20 eV) neutral atoms and molecules. The neutral beams are created using a method involving neutralization and reflection of ions from a biased limiter, where the ions are extracted from a toroidal plasma source. The spectra of emission due to beam-solid interactions on targets of Chemglaze Z-306 optical paint and Kapton are presented. Erosion yields for carbon and Kapton targets with low energy (approx. 10 eV) nitrogen and oxygen beams were measured. The reaction rates and surface morphology for the erosion of Kapton are similar to those measured in experiments on STS-5

Analisis Kesediaan Membayar Wtp (Willingness To Pay) dalam Upaya Pengelolaan Obyek Wisata Taman Alun Kapuas Pontianak, Kalimantan Barat

Berbagai fungsi yang terkait dengan sumber daya alam (fungsi ekologis, sosial, ekonomi, dan arsitektural) dannilai estetika yang dimilikinya (obyek dan lingkungan) dapat meningkatkan kualitas lingkungan dan untukkelangsungan kehidupan perkotaan juga dapat menjadi nilai kebanggaan dan identitas kota. Sebagai obyekwisata alam, Taman Alunalun Kapuas belum tertata dengan baik, pelaksanaan upaya pengelolaan objek wisataTaman Alun Kapuas membutuhkan biaya yang tidak sedikit. Untuk itu diharapkan bagi pengunjung untukmembayar dalam pengelolaan Taman Alun Kapuas. Penelitian ini menggunakan analisis regresi logistik dalammenganalisis faktor-faktor kesediaan pengunjung untuk membayar. Sedangkan metode CVM (ContingenValuation Method) digunakan untuk mengestimasi biaya yang akan dikeluarkan oleh pengunjung, dan metoderegresi berganda digunakan untuk menganalisis faktor-faktor apa yang mempengaruhi besar kesediaanmembayar pengunjung. Program yang dapat membantu dalam penelitian ini yaitu Microsoft Excel 2007 danMinitab For Windows Realise 16. Hasil penelitian menunjukkan bahwa sebanyak 84% responden bersediamembayar dalam upaya pengelolaan lingkungan obyek wisata Taman Alun Kapuas. Faktor-faktor yangmempengaruhi kesediaan membayar responden pengunjung dalam upaya pengelolaan lingkungan obyekwisata Taman Alun Kapuas antara lain pendapatan (PNDPTN3) dan pengetahuan (PNGTHUAN). Nilai rata-rataWTP responden pengunjung adalah sebesar Rp 3360,00/orang. Faktor yang mempengaruhi nilai WTPresponden yaitu usia (U)

Pembentukan 8-OHdG Dari Zat Toksik Pemicu Radikal Bebas

This study was conducted to observethe profile of DNA Adduct (8-OHdG) formation as DNA damage indicators, by using calf thymus DNA incubated with toxic and carcinogenic compounds. The compounds which could trigger free radicals in this research were PAH(Benzo[a]Pyrene), TiO2, and CuCl2. Calf thymus DNA was incubated with Benzo[a]Pyrene and CuCl2 compounds under pH and temperature variations. The incubation of calf thymus DNA with TiO2-UV radiation (254 nm) wasused to induce the formation of reactive oxygen species (ROS) in the process of oxidative DNA damage. From this research, all of compounds have potency to trigger the formation of DNA Adduct (8-OHdG). The ratio of absorbance to assess the purity of DNA at 260 nm and 280 nm (λ260/ λ280 ) was measured at ~1.9. The shifted peaks at λmax were indicating changes on structures of DNA as a result of calf thymus DNA incubation with B[a]P and CuCl2. The highest level of 8-OHdG results in calf thymus DNA incubation with B[a]P and CuCl2 under pH 8.5 and incubation temperature at 60°C, was about 120.856 μg/L. Calf thymus DNA incubation with TiO2-UV radiation (254 nm) under pH 8.5 resulting 8-OHdG level at 57.025 μg/L

Co-gasification of beech-wood and polyethylene in a fluidized-bed reactor

The co-gasification of beech-wood and polyethylene has been investigated in a lab-scale fluidised-bed reactor in the presence of four different types of bed materials (silica sand, olivine, Na-Y zeolite and ZSM-5 zeolite). ZSM-5 zeolite is very effective as a catalytic bed material in fluidized-bed reactor for wood-only gasification and cogasification in terms of high hydrogen production and CGE. Na-Y zeolite is more effective compared with ZSM-5 zeolite in co-gasification of the beech-wood and polyethylene process. The catalytic activity in co-gasification of beech-wood and polyethylene can be ranked accordingly: Na-Y zeolite > ZSM-5 zeolite > olivine. In general, higher amounts of steam injected in the fluidized-bed reactor and more polyethylene would lead to higher hydrogen production in the co-gasification proces

Assessing the Privacy Benefits of Domain Name Encryption

As Internet users have become more savvy about the potential for their Internet communication to be observed, the use of network traffic encryption technologies (e.g., HTTPS/TLS) is on the rise. However, even when encryption is enabled, users leak information about the domains they visit via DNS queries and via the Server Name Indication (SNI) extension of TLS. Two recent proposals to ameliorate this issue are DNS over HTTPS/TLS (DoH/DoT) and Encrypted SNI (ESNI). In this paper we aim to assess the privacy benefits of these proposals by considering the relationship between hostnames and IP addresses, the latter of which are still exposed. We perform DNS queries from nine vantage points around the globe to characterize this relationship. We quantify the privacy gain offered by ESNI for different hosting and CDN providers using two different metrics, the k-anonymity degree due to co-hosting and the dynamics of IP address changes. We find that 20% of the domains studied will not gain any privacy benefit since they have a one-to-one mapping between their hostname and IP address. On the other hand, 30% will gain a significant privacy benefit with a k value greater than 100, since these domains are co-hosted with more than 100 other domains. Domains whose visitors' privacy will meaningfully improve are far less popular, while for popular domains the benefit is not significant. Analyzing the dynamics of IP addresses of long-lived domains, we find that only 7.7% of them change their hosting IP addresses on a daily basis. We conclude by discussing potential approaches for website owners and hosting/CDN providers for maximizing the privacy benefits of ESNI.Comment: In Proceedings of the 15th ACM Asia Conference on Computer and Communications Security (ASIA CCS '20), October 5-9, 2020, Taipei, Taiwa

Mind the Gap: Investigating Toddlers’ Sensitivity to Contact Relations in Predictive Events

Toddlers readily learn predictive relations between events (e.g., that event A predicts event B). However, they intervene on A to try to cause B only in a few contexts: When a dispositional agent initiates the event or when the event is described with causal language. The current studies look at whether toddlers’ failures are due merely to the difficulty of initiating interventions or to more general constraints on the kinds of events they represent as causal. Toddlers saw a block slide towards a base, but an occluder prevented them from seeing whether the block contacted the base; after the block disappeared behind the occluder, a toy connected to the base did or did not activate. We hypothesized that if toddlers construed the events as causal, they would be sensitive to the contact relations between the participants in the predictive event. In Experiment 1, the block either moved spontaneously (no dispositional agent) or emerged already in motion (a dispositional agent was potentially present). Toddlers were sensitive to the contact relations only when a dispositional agent was potentially present. Experiment 2 confirmed that toddlers inferred a hidden agent was present when the block emerged in motion. In Experiment 3, the block moved spontaneously, but the events were described either with non-causal (“here’s my block”) or causal (“the block can make it go”) language. Toddlers were sensitive to the contact relations only when given causal language. These findings suggest that dispositional agency and causal language facilitate toddlers’ ability to represent causal relationships.John Templeton Foundation (#12667)James S. McDonnell Foundation (Causal Learning Collaborative Initiative)National Science Foundation (U.S.) (Career Award (# 0744213

Resource utilization and costs during the initial years of lung cancer screening with computed tomography in Canada

Background It is estimated that millions of North Americans would qualify for lung cancer screening and that billions of dollars of national health expenditures would be required to support population-based computed tomography lung cancer screening programs. The decision to implement such programs should be informed by data on resource utilization and costs. Methods Resource utilization data were collected prospectively from 2059 participants in the Pan-Canadian Early Detection of Lung Cancer Study using low-dose computed tomography (LDCT). Participants who had 2% or greater lung cancer risk over 3 years using a risk prediction tool were recruited from seven major cities across Canada. A cost analysis was conducted from the Canadian public payer's perspective for resources that were used for the screening and treatment of lung cancer in the initial years of the study. Results The average per-person cost for screening individuals with LDCT was USD453 (95% confidence interval [CI], USD400–USD505) for the initial 18-months of screening following a baseline scan. The screening costs were highly dependent on the detected lung nodule size, presence of cancer, screening intervention, and the screening center. The mean per-person cost of treating lung cancer with curative surgery was USD33,344 (95% CI, USD31,553–USD34,935) over 2 years. This was lower than the cost of treating advanced-stage lung cancer with chemotherapy, radiotherapy, or supportive care alone, (USD47,792; 95% CI, USD43,254–USD52,200; p = 0.061). Conclusion In the Pan-Canadian study, the average cost to screen individuals with a high risk for developing lung cancer using LDCT and the average initial cost of curative intent treatment were lower than the average per-person cost of treating advanced stage lung cancer which infrequently results in a cure

Financial Characteristics of Companies Audited by Large Audit Firms

Purpose “ The purpose of this paper is to examine how financial characteristics associated with the choice of a big audit firm with further investigation on the agency costs of free cash flows.Design/methodology/approach “ The sample used for this work includes industrial listed companies from Germany and France. To test our hypothesis, we used a number of logit models, extending the standard model selection audit firm, to include the variables of interest. Following previous work, our dependent dummy variable is Big4 or non-Big4.Findings “ We observed that most independent variables in the German companies show similar results to previous work, but we did not have the same results for the French industry. Moreover, our findings suggest that the total debt and dividends can be an important reason for determining the choice of a large audit firm, reducing agency costs of free cash flows.Research limitations/implications “ This study has some limitations on the measurements of the cost of the audit fees and also generates opportunities for additional searching.Originality/value “ The paper provides only one aspect to explain the relationship between the problems of agency costs of free cash flow and influence in choosing a large auditing firm, which stems from investors\u27 demand for higher quality audits

Characteristics of the TFTR limiter H-mode: The transition, ELMs, transport and confinement

H-Modes obtained through transitions from the supershot regime have been studied on TFTR. The characteristics of these H-modes are similar to those found on other tokamaks with one main exception, the density prof:des can be highly peaked. In the best cases the enhanced confinement in the core of the initial supershot is retained in the H-mode phase, while the confinement in a broad edge region is enhanced. Thus in TFTR, all of the important physics of H-modes such as transitions, enhanced edge confinement, ELMs and other phenomena are studied in a large circular limiter tokamak with the added feature of centrally peaked density profiles and the advantage of an extensive set of diagnostics. The threshold power for the transition is found to be a linear function of plasma current. Transitions and ELMs are affected by the mix of co-and counter-neutral beam injection (NBI) and by perturbations introduced by pellet injection, gas puffing, and current ramping before and during NBI. Fluctuations near both transition and ELM events have been characterized. High frequency magnetic fluctuations in the range {ge} 100--250 kHz usually decrease during the transition. Microwave scattering spectra of density fluctuations in the plasma edge show a feature at high frequency during the H-mode, which is not observed in the plasma core and which is consistent with an edge poloidal rotation velocity, V{sub {theta}}, of {approximately} 10{sup 4} m/s. The fluctuations begin at the transition, propagate in the direction of electron diamagnetic drift, and have modulation correlated with ELMs. Several TFTR H-modes showed a modest improvement in confinement over that of the supershots from which they originated, and an understanding of these may eventually lead to a plasma with the combined advantages of both the supershot and the H-mode. The characteristics and physics of the TFTR H-modes are considered relative to other tokamaks and in light of various theoretical studies