63,218 results on '"Pop A"'
Search Results
2. Resurrection of the Dead as an Element of Factionalism in the Corinthian Church Community
- Author
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Pop Andrei D.
- Subjects
resurrection ,dead ,corinthians ,community ,body ,Philosophy. Psychology. Religion - Abstract
Human tragedy could be summed up a single word—death. One first encounters it through the death of others, and then everyone faces it for themselves. The Christian faith confronts humanity’s final foe head on, delivering sustained hope amidst the sorrow and despair of impending death. This paper will first address the central role of the resurrection of the dead in First Corinthians. Second, the paper will present Paul’s retort to several challenges raised against the notion of the resurrection. Finally, the paper will attempt to systematize the means by which Paul proves the resurrection of the dead.
- Published
- 2022
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- View/download PDF
3. Use of the continuous glucose monitoring system in the management of hypoglicemia in insulin autoimmune syndrome
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Pop Andrada Raluca, Ruscanu Claudia Emanuela, Roman Gabriela, and Pascanu Ionela Maria
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insulin autoimune syndrome ,hirata’s disease ,continuous monitoring system ,insulin autoantibodies ,Medicine - Abstract
Background: Insulin autoimune syndrome (IAS), also known as Hirata’s disease, is a rare cause of spontaneous hyperinsulinemic hypoglicemia characterised by the presence of autoantibodies directed against human insulin (IAA).
- Published
- 2022
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4. A Cross-Lingual Meta-Learning Method Based on Domain Adaptation for Speech Emotion Recognition
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Ion, David-Gabriel, Smădu, Răzvan-Alexandru, Cercel, Dumitru-Clementin, Pop, Florin, and Cercel, Mihaela-Claudia
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Computer Science - Computation and Language - Abstract
Best-performing speech models are trained on large amounts of data in the language they are meant to work for. However, most languages have sparse data, making training models challenging. This shortage of data is even more prevalent in speech emotion recognition. Our work explores the model's performance in limited data, specifically for speech emotion recognition. Meta-learning specializes in improving the few-shot learning. As a result, we employ meta-learning techniques on speech emotion recognition tasks, accent recognition, and person identification. To this end, we propose a series of improvements over the multistage meta-learning method. Unlike other works focusing on smaller models due to the high computational cost of meta-learning algorithms, we take a more practical approach. We incorporate a large pre-trained backbone and a prototypical network, making our methods more feasible and applicable. Our most notable contribution is an improved fine-tuning technique during meta-testing that significantly boosts the performance on out-of-distribution datasets. This result, together with incremental improvements from several other works, helped us achieve accuracy scores of 83.78% and 56.30% for Greek and Romanian speech emotion recognition datasets not included in the training or validation splits in the context of 4-way 5-shot learning., Comment: 16 pages, 1 figure, Accepted by WISE 2024
- Published
- 2024
5. Thermalization of a flexible microwave stripline measured by a superconducting qubit
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Paluch, Patrick, Spiecker, Martin, Gosling, Nicolas, Adam, Viktor, Kammhuber, Jakob, Vermeulen, Kiefer, Bouman, Daniël, Wernsdorfer, Wolfgang, and Pop, Ioan M.
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Quantum Physics - Abstract
With the demand for scalable cryogenic microwave circuitry continuously rising, recently developed flexible microwave striplines offer the tantalyzing perspective of increasing the cabling density by an order of magnitude without thermally overloading the cryostat. We use a superconducting quantum circuit to test the thermalization of input flex cables with integrated $60\,$dB of attenuation distributed at various temperature stages. From the measured decoherence rate of a superconducting fluxonium qubit, we estimate a residual population of the readout resonator below $3.5\cdot10^{-3}$ photons and we measure a $0.28\,$ms thermalization time for the flexible stripline attenuators. Furthermore, we confirm that the qubit reaches an effective temperature of $26.4\,$mK, close to the base temperature of the cryostat, practically the same as when using a conventional semi-rigid coaxial cable setup.
- Published
- 2024
6. Enabling P-type Conduction in Bilayer WS2 with NbP Topological Semimetal Contacts
- Author
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Hoang, Lauren, Khan, Asir Intisar, Bennett, Robert K. A., Kim, Hyun-mi, Zhang, Zhepeng, Hocking, Marisa, Choi, Ae Rim, Oh, Il-Kwon, Mannix, Andrew J., and Pop, Eric
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Two-dimensional (2D) semiconductors are promising for low-power complementary metal oxide semiconductor (CMOS) electronics, which require ultrathin n- and p-type transistor channels. Among 2D semiconductors, WS2 is expected to have good conduction for both electrons and holes, but p-type WS2 transistors have been difficult to realize due to the relatively deep valence band and the presence of mid-gap states with conventional metal contacts. Here, we report topological semimetal NbP as p-type electrical contacts to bilayer WS2 with up to 5.8 microamperes per micron hole current at room temperature; this is the highest to date for sub 2 nm thin WS2 and more than 50 times larger than with metals like Ni or Pd. The p-type conduction is enabled by the simultaneously high work function and low density of states of the NbP, which reduce Fermi level pinning. These contacts are sputter-deposited at room temperature, an approach compatible with CMOS fabrication, a step towards enabling ultrathin WS2 semiconductors in future nanoelectronics.
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- 2024
7. Exceptional Reduction of Electrical Resistivity in Ultrathin Non-Crystalline NbP Semimetal
- Author
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Khan, Asir Intisar, Ramdas, Akash, Lindgren, Emily, Kim, Hyun-Mi, Won, Byoungjun, Wu, Xiangjin, Saraswat, Krishna, Chen, Ching-Tzu, Suzuki, Yuri, da Jornada, Felipe H., Oh, Il-Kwon, and Pop, Eric
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
The electrical resistivity of conventional metals, such as copper, is known to increase in thinner films due to electron-surface scattering, limiting the performance of metals in nanoscale electronics. Here, we uncover an exceptional reduction of resistivity with decreasing film thickness in NbP semimetal, deposited at relatively low temperatures of 400 {\deg}C. In sub-5 nm thin films, we find a significantly lower resistivity (~34 microOhm.cm for 1.5 nm thin NbP, at room temperature) than in the bulk form, and lower than conventional metals at similar thickness. Remarkably, the NbP films are not crystalline, but display local nanocrystalline, short-range order within an amorphous matrix. Our analysis suggests that the lower resistivity is due to conduction through surface channels, together with high surface carrier density and sufficiently good mobility, as the film thickness is reduced. These results and the fundamental insights obtained here could enable ultrathin, low-resistivity wires for nanoelectronics, beyond the limitations of conventional metals.
- Published
- 2024
8. In-situ tunable interaction with an invertible sign between a fluxonium and a post cavity
- Author
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Atanasova, Desislava G., Yang, Ian, Hönigl-Decrinis, Teresa, Gusenkova, Daria, Pop, Ioan M., and Kirchmair, Gerhard
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Quantum Physics ,Condensed Matter - Superconductivity - Abstract
Quantum computation with bosonic modes presents a powerful paradigm for harnessing the principles of quantum mechanics to perform complex information processing tasks. In constructing a bosonic qubit with superconducting circuits, nonlinearity is typically introduced to a cavity mode through an ancillary two-level qubit. However, the ancilla's spurious heating has impeded progress towards fully fault-tolerant bosonic qubits. The ability to in situ decouple the ancilla when not in use would be beneficial but has so far only been realized with tunable couplers or additional parametric drives. This work presents a novel architecture for quantum information processing, comprising a 3D post cavity coupled to a fluxonium ancilla via a readout resonator. This system's intricate energy level structure results in a complex landscape of interactions whose sign can be tuned in situ by the magnetic field threading the fluxonium loop without the need of additional elements. Our results could significantly advance the lifetime and controllability of bosonic qubits.
- Published
- 2024
9. CSPI-MT: Calibrated Safe Policy Improvement with Multiple Testing for Threshold Policies
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Cho, Brian M, Pop, Ana-Roxana, Gan, Kyra, Corbett-Davies, Sam, Nir, Israel, Evnine, Ariel, and Kallus, Nathan
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Computer Science - Machine Learning ,Statistics - Methodology ,Statistics - Machine Learning - Abstract
When modifying existing policies in high-risk settings, it is often necessary to ensure with high certainty that the newly proposed policy improves upon a baseline, such as the status quo. In this work, we consider the problem of safe policy improvement, where one only adopts a new policy if it is deemed to be better than the specified baseline with at least pre-specified probability. We focus on threshold policies, a ubiquitous class of policies with applications in economics, healthcare, and digital advertising. Existing methods rely on potentially underpowered safety checks and limit the opportunities for finding safe improvements, so too often they must revert to the baseline to maintain safety. We overcome these issues by leveraging the most powerful safety test in the asymptotic regime and allowing for multiple candidates to be tested for improvement over the baseline. We show that in adversarial settings, our approach controls the rate of adopting a policy worse than the baseline to the pre-specified error level, even in moderate sample sizes. We present CSPI and CSPI-MT, two novel heuristics for selecting cutoff(s) to maximize the policy improvement from baseline. We demonstrate through both synthetic and external datasets that our approaches improve both the detection rates of safe policies and the realized improvement, particularly under stringent safety requirements and low signal-to-noise conditions.
- Published
- 2024
10. Antibiotics administration during last trimester of pregnancy is associated with atopic dermatitis – a cross-sectional study
- Author
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Panduru Mihaela, Epure Adina Mihaela, Cimpoca Brindusa, Cozma Cristina, Giuca Brigitta Ana, Pop Andrei, Pop Gabriel, Simon Larisa Georgiana, Robu Mircea, and Panduru Nicolae Mircea
- Subjects
atopic dermatitis ,atopic eczema ,antibiotics ,antibiotherapy ,Internal medicine ,RC31-1245 - Abstract
Introduction. Studies regarding antibiotics administration during pregnancy and atopic dermatitis (AD) in children are only few. In this context, the objective of our study was to investigate the potential association between the timing of intrauterine exposure to antibiotics or prenatal antibiotic administration in general and AD occurrence in children.
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- 2020
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11. SOCIAL MEDIA AND ITS EFFECTS ON THE GROWTH OF BUSINESSES
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POP Anamaria-Mirabela and SIM Monica-Ariana
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media ,social media ,business ,customer engagement ,brand recognition ,Business ,HF5001-6182 ,Finance ,HG1-9999 - Abstract
Social media, and social networking, have changed the business landscape, both for companies that have adopted them and for those that have not. By definition, social media represent platforms where members share content with a wide audience, with the focus on the content, while social networking sites are more centered on conversations and groups having the same interests. Facebook, which pulls the line dividing the two types of interactions, has 600,000 regular users worldwide and welcomes companies, organizations, and brands to use its platform to connect with their audience. Almost all social networks have incorporated a measure of social media, allowing users to become curators of the interesting content they find, sharing links, images, and short personal stories. Businesses which have learned to create content and engage in conversations are already ‘in the stream' – and more and more, internet users expect they will be able to interact with their favorite brands. Companies that have embraced this have a definite advantage over those which have not. The aim of this paper is to investigate the role and economic impact of social media on businesses. It aims to investigate the benefits available from the use of the internet and social media sites for businesses. Social media have a positive impact on businesses and offer an opportunity for their audience to find them on social media. It helps to reach to their targeted audience, stay engaged with them and respond to their questions instantly. It is a great way to evaluate their competition by monitoring their social media pages. The paper focuses on the multiple positive impacts on business in terms of brand recognition, customer engagement, revenue, and customer service. It emphasizes the importance of social media in the growth of businesses, being also a great tool to evaluate their competitors and how they are using social media for their growth. By using social media, business are taking every opportunity to increase awareness of trade and development opportunities in a way that drives changes in behavior and inspires action. Doing so connects a certain industry with business opportunities abroad and leads to sustainable development in partner countries.
- Published
- 2020
12. IN THE DEFENSE OF TEACHERS IN TIMES OF CRISES – THOUGHTS, IDEAS, OPINIONS REGARDING TEACHERS
- Author
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SIM Monica-Ariana and POP Anamaria-Mirabela
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online teaching ,face-to-face education ,teachers ,educators ,Business ,HF5001-6182 ,Finance ,HG1-9999 - Abstract
The noble tradition that viewed the profession of teachers and teaching itself as an important service has lately been declining. Educators used to be considered a valuable human resource in guiding students towards a responsible future. The outbreak of coronavirus disease has been declared a Public Health Emergency of International Concern and the virus has now spread to many countries and territories. What we do know for sure is that it is transmitted through direct contact. Therefore, education premises have changed radically and so has the role of teachers. Measures taken by education institutions throughout the whole world tried to prevent the spread of the COVID-19 and consequently students and staff were lockdown. What is a teacher nowadays? This is the question that will try to find answers in this paper. Teachers assume the role of educators. Thanks to technology, they step backwards and delimit themselves from the role of authority they used to hold and become guides, facilitators, mentors and sometimes even supporters. Is it the time to adopt a different approach to teaching in general and teaching of English as a Foreign Language in particular? What is the role technology can play in education in the current socio-economic context? Does it throw shadows on the part played by teachers?
- Published
- 2020
13. Investigating the Impact of Semi-Supervised Methods with Data Augmentation on Offensive Language Detection in Romanian Language
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Nicola, Elena-Beatrice, Cercel, Dumitru-Clementin, and Pop, Florin
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Computer Science - Computation and Language - Abstract
Offensive language detection is a crucial task in today's digital landscape, where online platforms grapple with maintaining a respectful and inclusive environment. However, building robust offensive language detection models requires large amounts of labeled data, which can be expensive and time-consuming to obtain. Semi-supervised learning offers a feasible solution by utilizing labeled and unlabeled data to create more accurate and robust models. In this paper, we explore a few different semi-supervised methods, as well as data augmentation techniques. Concretely, we implemented eight semi-supervised methods and ran experiments for them using only the available data in the RO-Offense dataset and applying five augmentation techniques before feeding the data to the models. Experimental results demonstrate that some of them benefit more from augmentations than others., Comment: Accepted at KES 2024
- Published
- 2024
14. Pure kinetic inductance coupling for cQED with flux qubits
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Geisert, Simon, Ihssen, Soeren, Winkel, Patrick, Spiecker, Martin, Fechant, Mathieu, Paluch, Patrick, Gosling, Nicolas, Zapata, Nicolas, Günzler, Simon, Rieger, Dennis, Bénâtre, Denis, Reisinger, Thomas, Wernsdorfer, Wolfgang, and Pop, Ioan M.
- Subjects
Quantum Physics - Abstract
We demonstrate a qubit-readout architecture where the dispersive coupling is entirely mediated by a kinetic inductance. This allows us to engineer the dispersive shift of the readout resonator independent of the qubit and resonator capacitances. We validate the pure kinetic coupling concept and demonstrate various generalized flux qubit regimes from plasmon to fluxon, with dispersive shifts ranging from 60 kHz to 2 MHz at the half-flux quantum sweet spot. We achieve readout performances comparable to conventional architectures with quantum state preparation fidelities of 99.7 % and 92.7 % for the ground and excited states, respectively, and below 0.1 % leakage to non-computational states., Comment: 20 pages, 10 figures
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- 2024
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15. Excitation laser energy dependence of the gap-mode TERS spectra of WS$_2$ and MoS$_2$ on silver
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Krayev, Andrey, Isotta, Eleonora, Hoang, Lauren, Yang, Jerry A., Neilson, Kathryn, Wang, Minyuan, Haughn, Noah, Pop, Eric, Mannix, Andrew, Balogun, Oluwaseyi, and Wang, Chih-Feng
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We present a systematic study of the dependence of gap mode tip-enhanced Raman scattering (TERS) of mono- and bi-layer WS$_2$ and MoS$_2$ as a function of excitation laser energy. We collected consecutive TERS maps of mono-and bi-layer regions with 6 different excitation lasers. To decrease the acquisition time, we used for the first time concurrent excitation and collection with two lasers simultaneously. We found that the E$_{2g}$/A$_{1g}$ peak intensity ratio for bilayer WS$_2$@Ag and the A'/A$_{1g}$ peak intensity ratio of the out-of-plane modes for mono- and bilayer change in a significantly non-monotonous way with excitation laser energies from 1.58 to 2.62 eV. The former ratio increases at energies corresponding to A and B excitons in bilayer WS$_2$. The intensity of the A peak in the monolayer, and hence the A/A$_{1g}$ ratio, is surprisingly high at low excitation energies, dips dramatically at energy corresponding to the A exciton, and is restored partially in between A and B excitons, though still showing a descending trend with increasing energy. A similar picture was observed in mono- and bi-layer MoS$_2$, though the existing set of lasers did not match its excitonic profile as nicely as for WS$_2$. We attribute the observed behavior to intermediate (Fano resonance) or strong (Rabi splitting) coupling between the excitons in transition metal dichalcogenides (TMDs) and the plasmons in the tip-substrate nanocavity. This is akin to the so-called Fano (Rabi) transparency experimentally observed in far field scattering from TMDs between two plasmonic metals. The possibility of intermediate/strong coupling between excitonic resonances in TMDs and the nanocavity re-evaluates the role of resonances in gap-mode TERS and should become an important factor to be considered by TERS practitioners when planning experiments. Finally, we propose the ideal substrate for efficient TERS and tip enhanced photoluminescence measurements., Comment: 21 pages, 10 figures
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- 2024
16. Unexpected Benefits of Self-Modeling in Neural Systems
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Premakumar, Vickram N., Vaiana, Michael, Pop, Florin, Rosenblatt, Judd, de Lucena, Diogo Schwerz, Ziman, Kirsten, and Graziano, Michael S. A.
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Computer Science - Machine Learning - Abstract
Self-models have been a topic of great interest for decades in studies of human cognition and more recently in machine learning. Yet what benefits do self-models confer? Here we show that when artificial networks learn to predict their internal states as an auxiliary task, they change in a fundamental way. To better perform the self-model task, the network learns to make itself simpler, more regularized, more parameter-efficient, and therefore more amenable to being predictively modeled. To test the hypothesis of self-regularizing through self-modeling, we used a range of network architectures performing three classification tasks across two modalities. In all cases, adding self-modeling caused a significant reduction in network complexity. The reduction was observed in two ways. First, the distribution of weights was narrower when self-modeling was present. Second, a measure of network complexity, the real log canonical threshold (RLCT), was smaller when self-modeling was present. Not only were measures of complexity reduced, but the reduction became more pronounced as greater training weight was placed on the auxiliary task of self-modeling. These results strongly support the hypothesis that self-modeling is more than simply a network learning to predict itself. The learning has a restructuring effect, reducing complexity and increasing parameter efficiency. This self-regularization may help explain some of the benefits of self-models reported in recent machine learning literature, as well as the adaptive value of self-models to biological systems. In particular, these findings may shed light on the possible interaction between the ability to model oneself and the ability to be more easily modeled by others in a social or cooperative context.
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- 2024
17. The Structure of Financial Equity Research Reports -- Identification of the Most Frequently Asked Questions in Financial Analyst Reports to Automate Equity Research Using Llama 3 and GPT-4
- Author
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Pop, Adria, Spörer, Jan, and Handschuh, Siegfried
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Computer Science - Computers and Society ,Computer Science - Computational Engineering, Finance, and Science ,Computer Science - Information Retrieval ,Quantitative Finance - Computational Finance ,68T50, 91G15 ,I.2 ,I.7 - Abstract
This research dissects financial equity research reports (ERRs) by mapping their content into categories. There is insufficient empirical analysis of the questions answered in ERRs. In particular, it is not understood how frequently certain information appears, what information is considered essential, and what information requires human judgment to distill into an ERR. The study analyzes 72 ERRs sentence-by-sentence, classifying their 4940 sentences into 169 unique question archetypes. We did not predefine the questions but derived them solely from the statements in the ERRs. This approach provides an unbiased view of the content of the observed ERRs. Subsequently, we used public corporate reports to classify the questions' potential for automation. Answers were labeled "text-extractable" if the answers to the question were accessible in corporate reports. 78.7% of the questions in ERRs can be automated. Those automatable question consist of 48.2% text-extractable (suited to processing by large language models, LLMs) and 30.5% database-extractable questions. Only 21.3% of questions require human judgment to answer. We empirically validate using Llama-3-70B and GPT-4-turbo-2024-04-09 that recent advances in language generation and information extraction enable the automation of approximately 80% of the statements in ERRs. Surprisingly, the models complement each other's strengths and weaknesses well. The research confirms that the current writing process of ERRs can likely benefit from additional automation, improving quality and efficiency. The research thus allows us to quantify the potential impacts of introducing large language models in the ERR writing process. The full question list, including the archetypes and their frequency, will be made available online after peer review., Comment: JEL classes: C45; G11; G12; G14
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- 2024
18. Strong Charge-Photon Coupling in Planar Germanium Enabled by Granular Aluminium Superinductors
- Author
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Janík, Marián, Roux, Kevin, Espinosa, Carla Borja, Sagi, Oliver, Baghdadi, Abdulhamid, Adletzberger, Thomas, Calcaterra, Stefano, Botifoll, Marc, Manjón, Alba Garzón, Arbiol, Jordi, Chrastina, Daniel, Isella, Giovanni, Pop, Ioan M., and Katsaros, Georgios
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Condensed Matter - Mesoscale and Nanoscale Physics ,Quantum Physics - Abstract
High kinetic inductance superconductors are gaining increasing interest for the realisation of qubits, amplifiers and detectors. Moreover, thanks to their high impedance, quantum buses made of such materials enable large zero-point fluctuations of the voltage, boosting the coupling rates to spin and charge qubits. However, fully exploiting the potential of disordered or granular superconductors is challenging, as their inductance and, therefore, impedance at high values are difficult to control. Here we have integrated a granular aluminium resonator, having a characteristic impedance exceeding the resistance quantum, with a germanium double quantum dot and demonstrate strong charge-photon coupling with a rate of $g_\text{c}/2\pi= (566 \pm 2)$ MHz. This was achieved due to the realisation of a wireless ohmmeter, which allows \emph{in situ} measurements during film deposition and, therefore, control of the kinetic inductance of granular aluminium films. Reproducible fabrication of circuits with impedances (inductances) exceeding 13 k$\Omega$ (1 nH per square) is now possible. This broadly applicable method opens the path for novel qubits and high-fidelity, long-distance two-qubit gates.
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- 2024
19. Rethinking harmless refusals when fine-tuning foundation models
- Author
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Pop, Florin, Rosenblatt, Judd, de Lucena, Diogo Schwerz, and Vaiana, Michael
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Computer Science - Computation and Language ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
In this paper, we investigate the degree to which fine-tuning in Large Language Models (LLMs) effectively mitigates versus merely conceals undesirable behavior. Through the lens of semi-realistic role-playing exercises designed to elicit such behaviors, we explore the response dynamics of LLMs post fine-tuning interventions. Our methodology involves prompting models for Chain-of-Thought (CoT) reasoning and analyzing the coherence between the reasoning traces and the resultant outputs. Notably, we identify a pervasive phenomenon we term \emph{reason-based deception}, where models either stop producing reasoning traces or produce seemingly ethical reasoning traces that belie the unethical nature of their final outputs. We further examine the efficacy of response strategies (polite refusal versus explicit rebuttal) in curbing the occurrence of undesired behavior in subsequent outputs of multi-turn interactions. Our findings reveal that explicit rebuttals significantly outperform polite refusals in preventing the continuation of undesired outputs and nearly eliminate reason-based deception, challenging current practices in model fine-tuning. Accordingly, the two key contributions of this paper are (1) defining and studying reason-based deception, a new type of hidden behavior, and (2) demonstrating that rebuttals provide a more robust response model to harmful requests than refusals, thereby highlighting the need to reconsider the response strategies in fine-tuning approaches., Comment: ICLR 2024 AGI Workshop Poster
- Published
- 2024
20. LeanBin: Harnessing Lifting and Recompilation to Debloat Binaries
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Wodiany, Igor, Pop, Antoniu, and Luján, Mikel
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Computer Science - Software Engineering ,D.2.7 ,D.3.4 - Abstract
To reduce the source of potential exploits, binary debloating or specialization tools are used to remove unnecessary code from binaries. This paper presents a new binary debloating and specialization tool, LeanBin, that harnesses lifting and recompilation, based on observed execution traces. The dynamically recorded execution traces capture the required subset of instructions and control flow of the application binary for a given set of inputs. This initial control flow is subsequently augmented using heuristic-free static analysis to avoid excessively restricting the input space. The further structuring of the control flow and translation of binary instructions into a subset of C enables a lightweight generation of the code that can be recompiled, obtaining LLVM IR and a new debloated binary. Unlike most debloating approaches, LeanBin enables both binary debloating of the application and shared libraries, while reusing the existing compiler infrastructure. Additionally, unlike existing binary lifters, it does not rely on potentially unsound heuristics used by static lifters, nor suffers from long execution times, a limitation of existing dynamic lifters. Instead, LeanBin combines both heuristic-free static and dynamic analysis. The run time of lifting and debloating SPEC CPU2006 INT benchmarks has a geomean of 1.78$\times$, normalized to the native execution, and the debloated binary runs with a geomean overhead of 1.21$\times$. The percentage of gadgets, compared to the original binary, has a geomean between 24.10% and 30.22%, depending on the debloating strategy; and the code size can be as low as 53.59%. For the SQLite use-case, LeanBin debloats a binary including its shared library and generates a debloated binary that runs up to 1.24$\times$ faster with 3.65% gadgets., Comment: Accepted to ASE 2024; 14 pages, 7 figures
- Published
- 2024
21. Low-energy collisions between electrons and BeD$^+$
- Author
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Niyonzima, S., Pop, N., Iacob, F., Larson, Å., Orel, A. E., Mezei, J. Zs, Chakrabarti, K., Laporta, V., Hassouni, K., Benredjem, D., Bultel, A., Tennyson, J., Reiter, D., and Schneider, I. F.
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Physics - Plasma Physics ,Physics - Atomic Physics - Abstract
Multichannel quantum defect theory is applied in the treatment of the dissociative recombination and vibrational excitation processes for the BeD$^+$ ion in the twenty four vibrational levels of its ground electronic state ($\textrm{X}\,{^{1}\Sigma^{+}},v_{i}^{+}=0\ldots 23$). Three electronic symmetries of BeD$^{**}$ states (\ensuremath{^{2}\Pi}, \ensuremath{^{2}\Sigma^{+}}, and \ensuremath{^{2}\Delta}), are considered in the calculation of cross sections and the corresponding rate coefficients. The incident electron energy range is $10^{-5}$--2.7 eV and the electron temperature range is 100--5000~K. The vibrational dependence of these collisional processes is highlighted. The resulting data are useful in magnetic confinement fusion edge plasma modelling and spectroscopy, in devices with beryllium based main chamber materials, such as ITER and JET, and operating with the deuterium-tritium fuel mix. An extensive rate coefficients database is presented in graphical form and also by analytic fit functions whose parameters are tabulated in the supplementary material., Comment: 7 pages, 5 figures, 3 tables
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- 2024
- Full Text
- View/download PDF
22. CMOS-compatible Strain Engineering for High-Performance Monolayer Semiconductor Transistors
- Author
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Jaikissoon, Marc, Köroğlu, Çağıl, Yang, Jerry A., Neilson, Kathryn M., Saraswat, Krishna C., and Pop, Eric
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Physics - Applied Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science - Abstract
Strain engineering has played a key role in modern silicon electronics, having been introduced as a mobility booster in the 1990s and commercialized in the early 2000s. Achieving similar advances with two-dimensional (2D) semiconductors in a CMOS (complementary metal oxide semiconductor) compatible manner would radically improve the industrial viability of 2D transistors. Here, we show silicon nitride capping layers can impart strain to monolayer MoS2 transistors on conventional silicon substrates, enhancing their electrical performance with a low thermal budget (350 {\deg}C), CMOS-compatible approach. Strained back-gated and dual-gated MoS2 transistors demonstrate median increases up to 60% and 45% in on-state current, respectively. The greatest improvements are found when both transistor channels and contacts are reduced to ~200 nm, reaching saturation currents of 488 uA/um, higher than any previous reports at such short contact pitch. Simulations reveal that most benefits arise from tensile strain lowering the contact Schottky barriers, and that further reducing device dimensions (including contacts) will continue to offer increased strain and performance improvements.
- Published
- 2024
23. Rotational transitions induced by collisions of HD$^{+}$ ions with low energy electrons
- Author
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Motapon, O., Pop, N., Argoubi, F., Mezei, J. Zs., Epée, M. D. Epée, Faure, A., Telmini, M., Tennyson, J., and Schneider, I. F.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Atomic Physics - Abstract
A series of Multichannel Quantum Defect Theory-based computations have been performed, in order to produce the cross sections of rotational transitions (excitations $N_{i}^{+}-2 \rightarrow$ $N_{i}^{+}$, de-excitations $N_{i}^{+}$ $\rightarrow$ $N_{i}^{+}-2$, with $N_{i}^{+}=2$ to $10$) and of their competitive process, the dissociative recombination, induced by collisions of HD$^+$ ions with electrons in the energy range $10^{-5}$ to 0.3 eV. Maxwell anisotropic rate coefficients, obtained from these cross sections in the conditions of the Heidelberg Test Storage Ring (TSR) experiments ($k_{B}T_{t}=2.8$ meV and $k_{B}T_{l}=45$ $\mu$eV), have been reported for those processes in the same electronic energy range. Maxwell isotropic rate coefficients have been as well presented for electronic temperatures up to a few hundreds of Kelvins. Very good overall agreement is found between our results for rotational transitions and the former theoretical computations as well as with experiment. Furthermore, owing to the full rotational computations performed, the accuracy of the resulting dissociative recombination cross sections is considerably improved., Comment: 9 pages, 8 figures, 1 table. arXiv admin note: text overlap with arXiv:1107.5267
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- 2024
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- View/download PDF
24. Restricted isometric compression of sparse datasets into low-dimensional varieties
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Pop, Vasile, Teodorescu, Iuliana, and Teodorescu, Razvan
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Mathematical Physics ,Mathematics - Functional Analysis ,Mathematics - Optimization and Control ,Mathematics - Representation Theory ,Mathematics - Statistics Theory ,Primary: 30D05, Secondary: 30E10, 30E25 - Abstract
This article extends the known restricted isometric projection of sparse datasets in Euclidean spaces $\mathbb{R}^N$ down into low-dimensional subspaces $\mathbb{R}^k, k \ll N,$ to the case of low-dimensional varieties $\mathcal{M} \subset \mathbb{R}^N,$ of codimension $N - k = \omega(N)$. Applications to structured/hierarchical datasets are considered.
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- 2024
25. Dissociative recombination and vibrational excitation of BF$^{+}$ in low energy electron collisions
- Author
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Mezei, J. Zs, Colboc, F., Pop, N., Ilie, S., Chakrabarti, K., Niyonzima, S., Leppers, M., Bultel, A., Dulieu, O., Motapon, O., Tennyson, J., Hassouni, K., and Schneider, I. F.
- Subjects
Physics - Plasma Physics ,Physics - Atomic Physics - Abstract
The latest molecular data - potential energy curves and Rydberg-valence interactions - characterising the super-excited electronic states of BF are reviewed in order to provide the input for the study of their fragmentation dynamics. Starting from this input, the main paths and mechanisms of BF$^+$ dissociative recombination and vibrational excitation are analysed. Their cross sections are computed for the first time using a method based on the multichannel quantum defect theory (MQDT), and Maxwellian rate-coefficients are calculated and displayed in ready-to-be-used format for low temperature plasma kinetics simulations., Comment: 8 pages, 4 figures, 4 tables
- Published
- 2024
- Full Text
- View/download PDF
26. Matrix invertible extensions over commutative rings. Part III: Hermite rings
- Author
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Călugăreanu, Grigore, Pop, Horia F., and Vasiu, Adrian
- Subjects
Mathematics - Commutative Algebra - Abstract
We reobtain and often refine prior criteria due to Kaplansky, McGovern, Roitman, Shchedryk, Wiegand, and Zabavsky--Bilavska and obtain new criteria for a Hermite ring to be an \textsl{EDR}. We mention three criteria: (1) a Hermite ring $R$ is an \textsl{EDR} iff for all pairs $(a,c)\in R^2$, the product homomorphism $U(R/Rac)\times U\bigl(R/Rc(1-a)\bigr)\to U(R/Rc)$ between groups of units is surjective; (2) a reduced Hermite ring is an \textsl{EDR} iff it is a pre-Schreier ring and for each $a\in R$, every zero determinant unimodular $2\times 2$ matrix with entries in $R/Ra$ lifts to a zero determinant matrix with entries in $R$; (3) a B\'{e}zout domain $R$ is an \textsl{EDD} iff for all triples $(a,b,c)\in R^3$ there exists a unimodular pair $(e,f)\in R^2$ such that $(a,e)$ and $(be+af,1-a-bc)$ are unimodular pairs. We use these criteria to show that each B\'{e}zout ring $R$ that is an $(SU)_2$ ring (as introduced by Lorenzini) such that for each nonzero $a\in R$ there exists no nontrivial self-dual projective $R/Ra$-module of rank $1$ generated by $2$ elements (e.g., all its elements are squares), is an \textsl{EDR}., Comment: 19 pages. arXiv admin note: substantial text overlap with arXiv:2303.08413
- Published
- 2024
27. EU FUNDING – A POSITIVE IMPACT ON GDP?
- Author
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POP Andrada
- Subjects
GDP ,EU funds ,panel analysis ,linear regression ,Business ,HF5001-6182 ,Finance ,HG1-9999 - Abstract
A large number of countries believe that their economy has been boosted thanks to the EU funds. This is difficult to say yes because everyone comes up with different results. Experts in the field have performed numerous and diverse studies on this topic, using different types of methodologies and tools. Several hypothesizes have been tested and the general agreed conclusion is that the main reason for these results is not the amount of money obtained from the EU, but the way they are used. The pro-development way of utilizing the funds has increased the probability to generate valid economic growth. Moreover, long-term planning and strategic implementation regarding EU funds have proven to be more effective than short-time solutions. This paper proposes to analyze the impact of EU funds on the gross domestic product in ten European countries by using linear regression. The Member States must wish and plan for a sustainable, healthy growth, which will not cause the accumulation of risks, imbalances, and painful tensions, however, it will cause inevitable corrections in the future. To do this, countries need to focus on qualitative and not just quantitative growth, which will also determine the convergence of production structures and endowments with infrastructure, not just revenues. This would mean an increase in endowments with production factors. The focus is therefore on increasing the growth potential, an unobservable but extremely important variable of the economy. Many financial experts emphasized that countries of Central and Eastern Europe will spend EU money on the development of roads and railway infrastructure. There is a big recommendation on focusing on Research and Development, which is a tool that could help the economies of the region in the long term. The EU should motivate these countries to absorb the funds as quickly as possible by reprimanding the governments. Experience of best practices is a key element in EU funding and also the trigger for readjusting the framework and mindset of national stakeholders.
- Published
- 2020
28. Redesigning Summative Evaluation in Medical English
- Author
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Pop Anişoara
- Subjects
feedback ,medical english ,project-based evaluation ,summative evaluation ,English literature ,PR1-9680 - Abstract
Evaluation of discrete skills such as reading comprehension as well as vocabulary and grammar multiple choice testing are commonplace in Medical English examinations in higher education. But are these approaches to evaluation practically oriented enough so as to provide a clear image of what students can do with the language in a real life communicative context? This paper will present a case of projectbased evaluation with students in English for Medical Cosmetics likely to meet such challenges.
- Published
- 2019
- Full Text
- View/download PDF
29. Cardiac mesenchymal hamartoma associated with transposition of the great arteries in a neonate
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Stroe Valentin Ionut, Calburean Paul Adrian, Lates Gratiana Andreea, Al-Akel Cristina Flavia, Ghiragosian Claudiu, Pop Anisoara, Suciu Horatiu, and Horvath Emoke
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Medicine - Published
- 2019
- Full Text
- View/download PDF
30. Comparative sulfite assay by voltammetry using Pt electrodes, photometry and titrimetry: Application to cider, vinegar and sugar analysis
- Author
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Pisoschi Aurelia Magdalena and Pop Aneta
- Subjects
Sulfite food assay ,cyclic voltammetry ,Platinum electrodes ,orthophenanthroline photometry ,thiosulfate titrimetry ,Chemistry ,QD1-999 - Abstract
Sulfite is a widely applied preservation agent, against oxidative decay in foodstuffs and beverages. Among the analytical methods applied, electrochemical techniques exploit its facility to undergo oxidation. This paper aims at the comparative investigation of the performances exhibited by three analytical methodologies: cyclic voltammetry at different Pt working electrodes, the volumetric method employing sodium thiosulfate as titrating agent and the photocolorimetric method relying on the reduction of Fe3+-orthophenanthroline complex by sulfite. The cyclic voltammetric assay was performed at Pt strip and Pt ring electrodes, by linearly sweeping the potential between -100 and 1,500 mV. The linear range corresponded to 7.5 mg L-1 – 4.0 g L-1 for Pt strip working electrode and to 15.5 mg L-1 – 4.0 g L-1 for Pt ring working electrode. Relative standard deviations smaller than 3% showed repeatability. RSD values smaller than 3% were also obtained in the photometric assay, but the latter was characterised by a narrower linear range. The Pt strip electrode allowed wider linear range and lower sensitivity, whereas the Pt ring electrode with Ag/AgCl reference in the same unit was characterised by better repeatability. Applications involved sulfite assay in vinegar, brown sugar and cider samples with consistency between cyclic voltammetry and titrimetry.
- Published
- 2018
- Full Text
- View/download PDF
31. Mobility and Threshold Voltage Extraction in Transistors with Gate-Voltage-Dependent Contact Resistance
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Bennett, Robert K. A., Hoang, Lauren, Cremers, Connor, Mannix, Andrew J., and Pop, Eric
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Physics - Applied Physics ,Condensed Matter - Other Condensed Matter - Abstract
The mobility of emerging (e.g., two-dimensional, oxide, organic) semiconductors is commonly estimated from transistor current-voltage measurements. However, such devices often experience contact gating, i.e., electric fields from the gate modulate the contact resistance during measurements, which can lead conventional extraction techniques to estimate mobility incorrectly even by a factor >2. This error can be minimized by measuring transistors at high gate-source bias, |$V_\mathrm{gs}$|, but this regime is often inaccessible in emerging devices that suffer from high contact resistance or early gate dielectric breakdown. Here, we propose a method of extracting mobility in transistors with gate-dependent contact resistance that does not require operation at high |$V_\mathrm{gs}$|, enabling accurate mobility extraction even in emerging transistors with strong contact gating. Our approach relies on updating the transfer length method (TLM) and can achieve <10% error even in regimes where conventional techniques overestimate mobility by >2$\times$., Comment: Corrected values tabulated in Figure 2d (surrounding discussion/conclusions unchanged); updated discussion surrounding Monte Carlo approach for error propagation; corrected typos
- Published
- 2024
32. Matrix invertible extensions over commutative rings. Part II: determinant liftability
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Călugăreanu, Grigore, Pop, Horia F., and Vasiu, Adrian
- Subjects
Mathematics - Commutative Algebra - Abstract
A unimodular $2\times 2$ matrix $A$ with entries in a commutative ring $R$ is called weakly determinant liftable if there exists a matrix $B$ congruent to $A$ modulo $R\det(A)$ and $\det(B)=0$; if we can choose $B$ to be unimodular, then $A$ is called determinant liftable. If $A$ is extendable to an invertible $3\times 3$ matrix $A^+$, then $A$ is weakly determinant liftable. If $A$ is simple extendable (i.e., we can choose $A^+$ such that its $(3,3)$ entry is $0$), then $A$ is determinant liftable. We present necessary and/or sufficient criteria for $A$ to be (weakly) determinant liftable and we use them to show that if $R$ is a $\Pi_2$ ring in the sense of Part I (resp.\ is a pre-Schreier domain), then $A$ is simply extendable (resp.\ extendable) iff it is determinant liftable (resp.\ weakly determinant liftable). As an application we show that each $J_{2,1}$ domain (as defined by Lorenzini) is an elementary divisor domain., Comment: 13 pages. Part II of the splitting of arXiv:2303.08413
- Published
- 2024
33. Accuracy and repeatability of a parallel robot for personalised minimally invasive surgery
- Author
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Pisla, Doina, Tucan, Paul, Chablat, Damien, Hajjar, Nadim Al, Ciocan, Andra, Pisla, Adrian, Pusca, Alexandru, Radu, Corina, Pop, Grigore, and Gherman, Bogdan
- Subjects
Computer Science - Robotics - Abstract
The paper presents the methodology used for accuracy and repeatability measurements of the experimental model of a parallel robot developed for surgical applications. The experimental setup uses a motion tracking system (for accuracy) and a high precision measuring arm for position (for repeatability). The accuracy was obtained by comparing the trajectory data from the experimental measurement with a baseline trajectory defined with the kinematic models of the parallel robotic system. The repeatability was experi-mentally determined by moving (repeatedly) the robot platform in predefined points.
- Published
- 2024
34. The effects of V doping on the intrinsic properties of SmFe10Co2 alloys: a theoretical investigation
- Author
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Benea, Diana, Pop, Viorel, and Minár, Jan
- Subjects
Condensed Matter - Materials Science - Abstract
The present study focuses on the intrinsic properties of the SmFe10Co2-xVx (x = 0-2) alloys, which includes the SmFe10Co2 alloy, one of the most promising permanent magnets with the ThMn12 type of structure due to its large saturation magnetization (1.78 T), high Curie temperature (Tc = 859 K), and anisotropy field (12 T) experimentally obtained. Unfortunately, its low coercivity (<0.4 T) hinders its use in permanent magnet applications. The effect of V-doping on magnetization, magnetocrystalline anisotropy energy, and Curie temperature is investigated by electronic band structure calculations. The spin-polarized fully relativistic Korringa-Kohn-Rostoker (SPR-KKR) band structure method, which employs the coherent potential approximation (CPA) to deal with substitutional disorder, has been used. The Hubbard-U correction to local spin density approximation (LSDA +U) was used to account for the large correlation effects due to the 4f electronic states of Sm. The computed magnetic moments and magnetocrystalline anisotropy energies were compared with existing experimental data to validate the theoretical approach's reliability. The exchange-coupling parameters from the Heisenberg model were used for obtaining the mean-field estimated Curie temperature. The magnetic anisotropy energy was separated into contributions from transition metals and Sm, and its relationships with the local environment, interatomic distances, and valence electron delocalization were analyzed. The suitability of the hypothetical SmFe10CoV alloy for permanent magnet manufacture was assessed using the calculated anisotropy field, magnetic hardness, and intrinsic magnetic properties., Comment: 21 pages, 5 figures
- Published
- 2024
35. Matrix invertible extensions over commutative rings. Part I: general theory
- Author
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Călugăreanu, Grigore, Pop, Horia F., and Vasiu, Adrian
- Subjects
Mathematics - Commutative Algebra ,15A83, 13G05, 19B10, 13A05, 13F05, 15B33 - Abstract
A unimodular $2\times 2$ matrix with entries in a commutative $R$ is called extendable (resp.\ simply extendable) if it extends to an invertible $3\times 3$ matrix (resp.\ invertible $3\times 3$ matrix whose $(3,3)$ entry is $0$). We obtain necessary and sufficient conditions for a unimodular $2\times 2$ matrix to be extendable (resp.\ simply extendable) and use them to study the class $E_2$ (resp.\ $SE_2$) of rings $R$ with the property that all unimodular $2\times 2$ matrices with entries in $R$ are extendable (resp.\ simply extendable). We also study the larger class $\Pi_2$ of rings $R$ with the property that all unimodular $2\times 2$ matrices of determinant $0$ and with entries in $R$ are (simply) extendable (e.g., rings with trivial Picard groups or pre-Schreier domains). Among Dedekind domains, polynomial rings over $\mathbb Z$ and Hermite rings, only the EDRs belong to the class $E_2$ or $SE_2$. If $as(R)\le 2$, then $R$ is an $E_2$ ring iff it is an $SE_2$ ring., Comment: 17 pages in the original format (18 pages in the archive format). arXiv admin note: substantial text overlap with arXiv:2303.08413
- Published
- 2024
36. Rigorous derivation of an effective model for coupled Stokes advection, reaction and diffusion with freely evolving microstructure
- Author
-
Gahn, Markus, Peter, Malte A., Pop, Iuliu Sorin, and Wiedemann, David
- Subjects
Mathematics - Analysis of PDEs ,35B27, 35K57, 35R35, 76M50, 76S05, 80A19 - Abstract
We consider the homogenisation of a coupled Stokes flow and advection-reaction-diffusion problem in a perforated domain with an evolving microstructure of size $\varepsilon$. Reactions at the boundaries of the microscopic interfaces lead to the formation of a solid layer having a variable, a priori unknown thickness. This results in a growth or shrinkage of the solid phase and, thus, the domain evolution is not known a priori but induced by the advection-reaction-diffusion process. The achievements of this work are the existence and uniqueness of a weak microscopic solution and the rigorous derivation of an effective model for $\varepsilon \to 0$, based on $\varepsilon$-uniform a priori estimates. As a result of the limit passage, the processes on the macroscale are described by an advection-reaction-diffusion problem coupled to Darcy's equation with effective coefficients (porosity, diffusivity and permeability) depending on local cell problems. These local problems are formulated on cells, which depend on the macroscopic position and evolve in time. In particular, the evolution of these cells depends on the macroscopic concentration. Thus, the cell problems (respectively the effective coefficients) are coupled to the macroscopic unknowns and vice versa, leading to a strongly coupled micro-macro model. For pure reactive-diffusive transport coupled with microscopic domain evolution but without advective transport, homogenisation results have recently been presented. We extend these models by advective transport which is driven by the Stokes equation in the a priori unknown evolving pore domain., Comment: 44 pages
- Published
- 2024
37. Robust time-discretisation and linearisation schemes for singular and degenerate evolution systems modelling biofilm growth
- Author
-
Smeets, R. K. H., Mitra, K., Pop, I. S., and Sonner, S.
- Subjects
Mathematics - Numerical Analysis ,Mathematics - Analysis of PDEs ,65M12, 65M22, 35K51, 35K65 - Abstract
We propose and analyse numerical schemes for a system of quasilinear, degenerate evolution equations modelling biofilm growth as well as other processes such as flow through porous media and the spreading of wildfires. The first equation in the system is parabolic and exhibits degenerate and singular diffusion, while the second is either uniformly parabolic or an ordinary differential equation. First, we introduce a semi-implicit time discretisation that has the benefit of decoupling the equations. We prove the positivity, boundedness, and convergence of the time-discrete solutions to the time-continuous solution. Then, we introduce an iterative linearisation scheme to solve the resulting nonlinear time-discrete problems. Under weak assumptions on the time-step size, we prove that the scheme converges irrespective of the space discretisation and mesh. Moreover, if the problem is non-degenerate, the convergence becomes faster as the time-step size decreases. Finally, employing the finite element method for the spatial discretisation, we study the behaviour of the scheme, and compare its performance to other commonly used schemes. These tests confirm that the proposed scheme is robust and fast., Comment: 40 pages,7 figures, journal submission
- Published
- 2024
38. Granular Aluminum Parametric Amplifier for Low-Noise Measurements in Tesla Fields
- Author
-
Zapata, Nicolas, Takmakov, Ivan, Günzler, Simon, Nambisan, Ameya, Rieger, Dennis, Reisinger, Thomas, Wernsdorfer, Wolfgang, and Pop, Ioan M.
- Subjects
Quantum Physics - Abstract
Josephson junction parametric amplifiers have become essential tools for microwave quantum circuit readout with minimal added noise. Even after improving at an impressive rate in the last decade, they remain vulnerable to magnetic field, which limits their use in many applications such as spin qubits, Andreev and molecular magnet devices, dark matter searches, etc. Kinetic inductance materials, such as granular aluminum (grAl), offer an alternative source of non-linearity with innate magnetic field resilience. We present a non-degenerate amplifier made of two coupled grAl resonators resilient to in-plane magnetic field up to 1 T. It offers 20 dB of gain close to the quantum limit of added noise, with a gain-bandwidth product of 28 MHz and -110 dBm input saturation power.
- Published
- 2024
39. Chemically Tailored Growth of 2D Semiconductors via Hybrid Metal-Organic Chemical Vapor Deposition
- Author
-
Zhang, Zhepeng, Hoang, Lauren, Hocking, Marisa, Hu, Jenny, Zaborski Jr., Gregory, Reddy, Pooja, Dollard, Johnny, Goldhaber-Gordon, David, Heinz, Tony F., Pop, Eric, and Mannix, Andrew J.
- Subjects
Physics - Applied Physics ,Condensed Matter - Materials Science - Abstract
Two-dimensional (2D) semiconducting transition-metal dichalcogenides (TMDCs) are an exciting platform for new excitonic physics and next-generation electronics, creating a strong demand to understand their growth, doping, and heterostructures. Despite significant progress in solid-source (SS-) and metal-organic chemical vapor deposition (MOCVD), further optimization is necessary to grow highly crystalline 2D TMDCs with controlled doping. Here, we report a hybrid MOCVD growth method that combines liquid-phase metal precursor deposition and vapor-phase organo-chalcogen delivery to leverage the advantages of both MOCVD and SS-CVD. Using our hybrid approach, we demonstrate WS$_2$ growth with tunable morphologies - from separated single-crystal domains to continuous monolayer films - on a variety of substrates, including sapphire, SiO$_2$, and Au. These WS$_2$ films exhibit narrow neutral exciton photoluminescence linewidths down to 33 meV and room-temperature mobility up to 34 - 36 cm$^2$V$^-$$^1$s$^-$$^1$). Through simple modifications to the liquid precursor composition, we demonstrate the growth of V-doped WS$_2$, MoxW$_1$$_-$$_x$S$_2$ alloys, and in-plane WS$_2$-MoS$_2$ heterostructures. This work presents an efficient approach for addressing a variety of TMDC synthesis needs on a laboratory scale.
- Published
- 2024
40. Graph-based variant discovery reveals novel dynamics in the human microbiome
- Author
-
Muralidharan, Harihara Subrahmaniam, Michaelis, Jacquelyn S, Ghurye, Jay, Treangen, Todd, Koren, Sergey, Fedarko, Marcus, and Pop, Mihai
- Subjects
Quantitative Biology - Genomics - Abstract
Sequence differences between the strains of bacteria comprising host-associated and environmental microbiota may play a role in community assembly and influence the resilience of microbial communities to disturbances. Tools for characterizing strain-level variation within microbial communities, however, are limited in scope, focusing on just single nucleotide polymorphisms, or relying on reference-based analyses that miss complex functional and structural variants. Here, we demonstrate the power of assembly graph analysis to detect and characterize structural variants in almost 1,000 metagenomes generated as part of the Human Microbiome Project. We identify over nine million variants comprising insertion/deletion events, repeat copy-number changes, and mobile elements such as plasmids. We highlight some of the potential functional roles of these genomic changes. Our analysis revealed striking differences in the rate of variation across body sites, highlighting niche-specific mechanisms of bacterial adaptation. The structural variants we detect also include potentially novel prophage integration events, highlighting the potential use of graph-based analyses for phage discovery.
- Published
- 2024
41. MetaCompass: Reference-guided Assembly of Metagenomes
- Author
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Luan, Tu, Cepeda, Victoria, Liu, Bo, Bowen, Zac, Ayyangar, Ujjwal, Almeida, Mathieu, Hill, Christopher M., Koren, Sergey, Treangen, Todd J., Porter, Adam, and Pop, Mihai
- Subjects
Quantitative Biology - Genomics ,Quantitative Biology - Quantitative Methods - Abstract
Metagenomic studies have primarily relied on de novo assembly for reconstructing genes and genomes from microbial mixtures. While reference-guided approaches have been employed in the assembly of single organisms, they have not been used in a metagenomic context. Here we describe the first effective approach for reference-guided metagenomic assembly that can complement and improve upon de novo metagenomic assembly methods for certain organisms. Such approaches will be increasingly useful as more genomes are sequenced and made publicly available., Comment: 18 pages, 6 figures, 3 tables, one supplementary material
- Published
- 2024
42. Features of strangeness production in pp and heavy ion collisions
- Author
-
Pop, A. and Petrovici, M.
- Subjects
High Energy Physics - Phenomenology - Abstract
Based on the existing experimental data for A-A collisions starting from the AGS energies up to the LHC ones, various systematics related to strange hadrons and anti-hadrons are presented. The ratio between the average transverse momentum and the square root of the total particle multiplicity per unit rapidity and unit transverse overlap area decreases with collision energy for a given centrality or with centrality for a given collision energy, thus supporting the predictions of CGC and percolation based approaches. The dependence on the square root of the total multiplicity per unit rapidity and unit transverse overlap area of the slope and offset extracted from the $\langle p_T\rangle$-particle mass correlation and of the average transverse expansion velocity and kinetic freeze-out temperature parameters obtained from BGBW fits of the pT spectra for strange hadrons is compared to that for pions, kaons and protons. The detailed study of the entropy density dependence of the ratio of strange hadron yields per unit rapidity to the total particle multiplicity per unit rapidity, at different collision energies and centralities, reveals the necessity to study separately strange hadrons and anti-hadrons. The correlation between the ratio of the single- and multi- strange anti-hadron yield per unit rapidity to the total particle multiplicity per unit rapidity and the entropy density is presented as a function of the fireball size. A maximum is evidenced in the similar correlation established for combined and separate species of strange hadrons, at different centralities, in the region where a transition from the baryon-dominated matter to the meson-dominated one takes place. The position of this maximum does not depend on the mass of the corresponding strange hadron. Comparison with pp experimental data reveals another similarity between pp and Pb-Pb collisions at the LHC energies., Comment: 13 pages, 26 figures
- Published
- 2024
43. Direct Exfoliation of Nanoribbons from Bulk van der Waals Crystals
- Author
-
Saunders, Ashley P., Chen, Victoria, Wang, Jierong, Johnson, Amalya C., McKeown-Green, Amy S., Zeng, Helen J., Mac, T. Kien, Trinh, Tuan, Heinz, Tony F., Pop, Eric, and Liu, Fang
- Subjects
Condensed Matter - Materials Science - Abstract
Confinement of monolayers into quasi-one-dimensional atomically-thin nanoribbons could lead to novel quantum phenomena beyond those achieved in their bulk and monolayer counterparts. However, current experimental availability of nanoribbon species beyond graphene has been limited to bottom-up synthesis or top-down patterning. In this study, we introduce a versatile and direct lithography-free approach to exfoliate a variety of bulk van der Waals (vdW) crystals into nanoribbons. Akin to the Scotch tape exfoliation in producing monolayers, this technique provides convenient access to a wide range of nanoribbons derived from their corresponding bulk crystals, including MoS2, WS2, MoSe2, WSe2, MoTe2, WTe2, ReS2, and hBN. The nanoribbons are single-crystalline, parallel-aligned, flat, and have high aspect ratio. We demonstrated the electrical, magnetic, and optical properties from the confinement, strain, and edge configurations of these nanoribbons. This versatile preparation technique will pave the way for future experimental investigation and broad applications in optoelectronic, sensing, electronic and quantum devices., Comment: 18 pages, 5 figures
- Published
- 2024
44. Toward Mass-Production of Transition Metal Dichalcogenide Solar Cells: Scalable Growth of Photovoltaic-Grade Multilayer WSe2 by Tungsten Selenization
- Author
-
Neilson, Kathryn M., Hamtaei, Sarallah, Nazif, Koosha Nassiri, Carr, Joshua M., Rahimisheikh, Sepideh, Nitta, Frederick U., Brammertz, Guy, Blackburn, Jeffrey L., Hadermann, Joke, Saraswat, Krishna C., Reid, Obadiah G., Vermang, Bart, Daus, Alwin, and Pop, Eric
- Subjects
Condensed Matter - Materials Science - Abstract
Semiconducting transition metal dichalcogenides (TMDs) are promising for high-specific-power photovoltaics due to desirable band gaps, high absorption coefficients, and ideally dangling-bond-free surfaces. Despite their potential, the majority of TMD solar cells are fabricated in a non-scalable fashion using exfoliated materials due to the absence of high-quality, large-area, multilayer TMDs. Here, we present the scalable, thickness-tunable synthesis of multilayer tungsten diselenide (WSe$_{2}$) films by selenizing pre-patterned tungsten with either solid source selenium or H$_{2}$Se precursors, which leads to smooth, wafer-scale WSe$_{2}$ films with a layered van der Waals structure. The films have charge carrier lifetimes up to 144 ns, over 14x higher than large-area TMD films previously demonstrated. Such high carrier lifetimes correspond to power conversion efficiency of ~22% and specific power of ~64 W g$^{-1}$ in a packaged solar cell, or ~3 W g$^{-1}$ in a fully-packaged solar module. This paves the way for the mass-production of high-efficiency multilayer WSe$_{2}$ solar cells at low cost.
- Published
- 2024
45. Investigation of Different Throat Concepts for Precipitation Processes in Saturated Pore-Network Models
- Author
-
Schollenberger, Theresa, von Wolff, Lars, Bringedal, Carina, Pop, Iuliu Sorin, Rohde, Christian, and Helmig, Rainer
- Published
- 2024
- Full Text
- View/download PDF
46. Axon-like active signal transmission
- Author
-
Brown, Timothy D., Zhang, Alan, Nitta, Frederick U., Grant, Elliot D., Chong, Jenny L., Zhu, Jacklyn, Radhakrishnan, Sritharini, Islam, Mahnaz, Fuller, Elliot J., Talin, A. Alec, Shamberger, Patrick J., Pop, Eric, Williams, R. Stanley, and Kumar, Suhas
- Published
- 2024
- Full Text
- View/download PDF
47. Free convective heat transfer flow in a glass bead porous medium varying permeability and sinusoidal wall temperature
- Author
-
Rahman, Mohammad M., Saghir, M. Ziad, Vajravelu, Kuppalapalle, and Pop, Ioan
- Published
- 2024
- Full Text
- View/download PDF
48. MHD Mixed Convection Flow Over a Permeable Vertical Flat Plate Embedded in a Darcy–Forchheimer Porous Medium
- Author
-
Merkin, John H., Roșca, Natalia C., Roșca, Alin V., and Pop, Ioan
- Published
- 2024
- Full Text
- View/download PDF
49. Something old, new, and borrowed. Rise of the systematic reviews
- Author
-
Hognogi, Gheorghe-Gavrilă and Pop, Ana-Maria
- Published
- 2024
- Full Text
- View/download PDF
50. Rapid Synthesis and Evaluation of Resveratrol-Piperazine Cocrystals by Ultrasound and Microwave Methods
- Author
-
Ioniţă, Simona, Pătrașcu, Mariana, Soare, Elena Mirabela, Lincu, Daniel, Atkinson, Irina, Rusu, Adriana, Pop, Mihaela Maria, Iordache, Coca, Ușurelu, Cătălina-Diana, Baltac, Andreea Simona, Mitran, Raul-Augustin, Pandele-Cuşu, Jeanina, and Fruth, Victor
- Published
- 2024
- Full Text
- View/download PDF
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