Orientation in Friedel-Crafts Acetylation of Nerolineand Its 6-Alkyl Homologues

The Friedel-Crafts acetylation of neroline in nitrobenzene medium is shown to result predominantly either in 1- or in 6-substitution,depending on the experimental conditions; as a byproduct, 1,6-diacetyl-2-methoxynaphthalene is obtained. Further,it is shown that 6-alkylated nerolines such as 6-propyl-2-methoxynaphthalene, are acetylated in position 1, even in nitrobenzene medium, and that 1,6-dialkylated nerolines such as 6-ethyl-2- methoxy-1-methylnaphthalene, can also be acetylated, whilst 1,6-dialkyl-2-naphthols are unable to undergo Nencki acylation reactions. In the course of this work, certain errors in the literature have been corrected

Orientation in Friedel-Crafts Acetylation of Nerolineand Its 6-Alkyl Homologues

The Friedel-Crafts acetylation of neroline in nitrobenzene medium is shown to result predominantly either in 1- or in 6-substitution,depending on the experimental conditions; as a byproduct, 1,6-diacetyl-2-methoxynaphthalene is obtained. Further,it is shown that 6-alkylated nerolines such as 6-propyl-2-methoxynaphthalene, are acetylated in position 1, even in nitrobenzene medium, and that 1,6-dialkylated nerolines such as 6-ethyl-2- methoxy-1-methylnaphthalene, can also be acetylated, whilst 1,6-dialkyl-2-naphthols are unable to undergo Nencki acylation reactions. In the course of this work, certain errors in the literature have been corrected

NLO-QCD Corrections to Dilepton Production in the Randall-Sundrum Model

The dilepton production process at hadron colliders in the Randall-Sundrum (RS) model is studied at next-to-leading order in QCD. The NLO-QCD corrections have been computed for the virtual graviton exchange process in the RS model, in addition to the usual gamma, Z-mediated processes of standard Drell-Yan. K-factors for the cross-sections at the LHC and Tevatron for differential in the invariant mass, Q, and the rapidity, Y, of the lepton pair are presented. We find the K-factors are large over substantial regions of the phase space.Comment: 24 pages, 12 figure

Assessing Mixed Reality Voice Dictation with Background Noise

Mixed reality devices, such as the Microsoft HoloLens 2, are growing in popularity and have been adopted in domains like education, aviation, and medicine. Text entry interaction is essential for daily activities: texting, using websites, and taking notes. However, typing long messages using the HoloLens’ virtual keyboard can be slow and cumbersome. The voice dictation provides a speech-to-text interaction that requires less physical effort and time by allowing users to verbalize messages and translate them into the text without manual input. Still, HoloLens 1’s dictation method was specifically problematic when the background noise exceeded 60 dB, which is common in many work environments. Consequently, less than half of the participants could dictate phrases in the high noise condition. However, the HoloLens 2 has improved the voice dictation to function in a higher background noise level with a maximum of 90 dB (Strange, 2019). This study will examine the user experience and the extent to which different background noise conditions impact voice dictation efficiency and effectiveness using the Microsoft HoloLens 2. The results will be compared to the past research on the HoloLens 1 (Derby et al., 2020). In addition, user perceptions and feedback will help create recommendations for future improvements

High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism

The readout of semiconductor spin qubits based on spin blockade is fast but suffers from a small charge signal. Previous work suggested large benefits from additional charge mapping processes, however uncertainties remain about the underlying mechanisms and achievable fidelity. In this work, we study the single-shot fidelity and limiting mechanisms for two variations of an enhanced latching readout. We achieve average single-shot readout fidelities > 99.3% and > 99.86% for the conventional and enhanced readout respectively, the latter being the highest to date for spin blockade. The signal amplitude is enhanced to a full one-electron signal while preserving the readout speed. Furthermore, layout constraints are relaxed because the charge sensor signal is no longer dependent on being aligned with the conventional (2, 0) - (1, 1) charge dipole. Silicon donor-quantum-dot qubits are used for this study, for which the dipole insensitivity substantially relaxes donor placement requirements. One of the readout variations also benefits from a parametric lifetime enhancement by replacing the spin-relaxation process with a charge-metastable one. This provides opportunities to further increase the fidelity. The relaxation mechanisms in the different regimes are investigated. This work demonstrates a readout that is fast, has one-electron signal and results in higher fidelity. It further predicts that going beyond 99.9% fidelity in a few microseconds of measurement time is within reach.Comment: Supplementary information is included with the pape

Low temperature (down to 450° C) annealed TiAl contacts on N-type gallium nitride characterized by differential scanning calorimetry

International audienceThis work reports on Differential Scanning Calorimetry (DSC) measurements performed on Ti-Al metallic layers stacks deposited on n+-GaN. The aim is to get better understanding of the mechanisms leading to ohmic contact formation during the annealing stage. Two exothermic peaks were found, one below 500°C and the other one around 660°C. They can be respectively attributed to Al3Ti and Al2Ti compounds formation. The locations of these peaks provide clear evidence of solid-solid reac-tions. Lowest contact resistance is well correlated with the presence of Al3Ti compound, corresponding to Al(200nm)/Ti(50nm) stoichiometric ratio. Subsequently, Al(200 nm)Ti(50 nm) stacks on n+-GaN were annealed from 400°C to 650°C. Specific Contact Resistivity (SCR) values stay in the mid 10-5 Ω.cm² range for annealing temperatures between 450°C and 650°C. Such low-temperature annealed contacts on n+-GaN may open new device processing routes, simpler and cheaper, in which Ohmic and Schottky contacts are annealed together

PENERAPAN PENDEKATAN BERMAIN UNTUK MENINGKATKAN HASIL BELAJAR LOMPAT JAUH SISWA SMP NEGERI 2 LEMBANG

Penelitian ini bertujuan untuk mengetahui apakah dengan penerapan pendekatan bermain dapat meningkatkan hasil belajar lompat jauh siswa SMP Negeri 2 Lembang. Metode penelitian yang digunakan adalah metode penelitian tindakan kelas. Subjek penelitian ini adalah siswa kelas VII A SMPN 2 Lembang dengan jumlah 36 orang siswa sebagai sampel. Hasil penelitian ini menunjukkan, ada peningkatan keterampilan lompat jauh pada siswa dengan menggunakan pendekatan bermain. Pada tes awal, 15 siswa sudah mencapai kriteria ketuntasan minimal (KKM) dengan persentase ketuntasan klasikal 41,67 %. Pada siklus I, siswa yang telah mencapai KKM meningkat menjadi 20 siswa dengan persentase 55,56 %. Hasil pada siklus II, meningkat menjadi 30 siswa dengan persentase klasikal sebesar 83,33 %. Jika dilihat berdasarkan nilai rata-rata siswa di kelas, maka hasil tes awal siswa diperoleh rata-rata 66,89. Pada siklus I, nilai rata-rata siswa menjadi 73,58. Hasil siklus I tersebut belum mencapai harapan peneliti yang menargetkan pencapaian rata-rata kelas ≥ 75. Memasuki siklus II, perolehan nilai rata-rata siswa mencapai 80,53 dan artinya sudah mencapai target peneliti. Dengan demikian dapat disimpulkan bahwa penerapan pendekatan bermain berpengaruh untuk meningkatkan hasil belajar lompat jauh. Kata Kunci : Pendekatan Bermain, Lompat Jauh, Hasil Belajar. ABSTRACT This study aims to determine whether the application of the approach to play can improve learning outcomes long jump students SMP Negeri 2 Lembang. The research method used is classroom action research method. The subjects of this study were students of class VII A SMPN 2 Lembang with 36 students as a sample. The results of this study indicate, there is an increase in skill long jumps on students by using a play approach. In the initial test, 15 students had achieved minimal mastery criteria (KKM) with a percentage of classical completeness of 41.67%. In the first cycle, students who have reached KKM increased to 20 students with a percentage of 55.56%. Results in cycle II, increased to 30 students with a classical percentage of 83.33%. When viewed based on the average score of students in the class, then the results of the initial test students obtained an average of 66.89. In cycle I, the average score of the students was 73.58. The results of the cycle I have not reached the expectations of researchers who target the achievement of the average class ≥ 75. Entering cycle II, the average score of students reaches 80.53 and means it has reached the target researchers. Thus it can be concluded that the application of an influential play approach to improve the results of long jump learning. Keywords: Approach to Play, Long Jump, Learning Outcomes

Behavioral Modernity and the Cultural Transmission of Structured Information: The Semantic Axelrod Model

Cultural transmission models are coming to the fore in explaining increases in the Paleolithic toolkit richness and diversity. During the later Paleolithic, technologies increase not only in terms of diversity but also in their complexity and interdependence. As Mesoudi and O'Brien (2008) have shown, selection broadly favors social learning of information that is hierarchical and structured, and multiple studies have demonstrated that teaching within a social learning environment can increase fitness. We believe that teaching also provides the scaffolding for transmission of more complex cultural traits. Here, we introduce an extension of the Axelrod (1997} model of cultural differentiation in which traits have prerequisite relationships, and where social learning is dependent upon the ordering of those prerequisites. We examine the resulting structure of cultural repertoires as learning environments range from largely unstructured imitation, to structured teaching of necessary prerequisites, and we find that in combination with individual learning and innovation, high probabilities of teaching prerequisites leads to richer cultural repertoires. Our results point to ways in which we can build more comprehensive explanations of the archaeological record of the Paleolithic as well as other cases of technological change.Comment: 24 pages, 7 figures. Submitted to "Learning Strategies and Cultural Evolution during the Paleolithic", edited by Kenichi Aoki and Alex Mesoudi, and presented at the 79th Annual Meeting of the Society for American Archaeology, Austin TX. Revised 5/14/1