206 research outputs found

    spl(2,1) dynamical supersymmetry and suppression of ferromagnetism in flat band double-exchange models

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    The low energy spectrum of the ferromagnetic Kondo lattice model on a N-site complete graph extended with on-site repulsion is obtained from the underlying spl(2,1) algebra properties in the strong coupling limit. The ferromagnetic ground state is realized for 1 and N+1 electrons only. We identify the large density of states to be responsible for the suppression of the ferromagnetic state and argue that a similar situation is encountered in the Kagome, pyrochlore, and other lattices with flat bands in their one-particle density of states.Comment: 7 pages, 1 figur

    Analysis of Patients Visiting Niigata University Medical and Dental Hospital with Chief Complaints of Metal Allergy And/or Focal Infection in the Previous 8 Years

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    Dental metal allergy and dental focal infection are possible causes of dermatological diseases, but have been the subjects of few reports to date. We have been treating such patients in our special clinic for more than 20 years.The purpose of the present study was to investigate the mouths of patients visiting our dental hospital over an 8-year period, with the aim of clarifying whether dental metal allergy and/or dental focal infection affects their dermatologic conditions.We surveyed all clinical records of the 185 patients who visited Niigata University Medical and Dental Hospital with chief complaints of dental metal allergy since 2002. Diagnostics of skin diseases, periodontal records, periapical lesions, dental caries, dental metal series patch test results and Electron Probed Micro-Analysis (EPMA) data were investigated. Ninety-two (49%) patients were suffering from pustulosis palmaris et plantaris and 20 (11%) patients had lichen planus. Eighty-two (49%) patients showed positive reactions on patch testing. Based on the result of patch tests, Ni showed the highest positivity rate (62%, 51 patients), but on EPMA, the number of patients with Ni as an allergen was 14 (27%). On the other hand, more than 98% of patients who showed positive reactions on patch test to Pd and Au had these metals in their dental prostheses. In addition, 112 (60%) patients showed the possibility of dental focal infection

    Interactive Planning Using Large Language Models for Partially Observable Robotics Tasks

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    Designing robotic agents to perform open vocabulary tasks has been the long-standing goal in robotics and AI. Recently, Large Language Models (LLMs) have achieved impressive results in creating robotic agents for performing open vocabulary tasks. However, planning for these tasks in the presence of uncertainties is challenging as it requires \enquote{chain-of-thought} reasoning, aggregating information from the environment, updating state estimates, and generating actions based on the updated state estimates. In this paper, we present an interactive planning technique for partially observable tasks using LLMs. In the proposed method, an LLM is used to collect missing information from the environment using a robot and infer the state of the underlying problem from collected observations while guiding the robot to perform the required actions. We also use a fine-tuned Llama 2 model via self-instruct and compare its performance against a pre-trained LLM like GPT-4. Results are demonstrated on several tasks in simulation as well as real-world environments. A video describing our work along with some results could be found here.Comment: 22 pages, 4 figure

    Series-Parallel and Parallel Identification Schemes for a Class of Continuous Nonlinear Systems

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    Fig. 4(a) shows the parameter estimates under the existence of the measmable disturbance (di = 5, a\ = 0) with the parameter estimates under the ideal condition (di = a\ = 0) overlaid. Since the inserted DDR's remove the disturbance from the inputoutput relation, the disturbance does not slow down the identification speed. Fig. 4(6) shows the parameter estimates under the existence of the unmeasurable disturbance (di = 0, d 2 = 1) with the parameter estimates under the ideal condition (di = di = 0) overlaid. There exists no difference between the two cases as far as the identification speed is concerned. In the simulation, the step disturbances, di and d 2 , were injected to the plant at k = 0. Thus, strictly speaking, at k = 0, di(k) and d 2 (fc) did not satisfy equation V Conclusions Adverse effects of deterministic disturbances in linear identification have been pointed out, and a method to remove such effects has been presented. This method works for measurable and unmeasurable disturbances which can be regarded as the outputs of free systems with known dynamics. The unmeasurable disturbance must always be removed to achieve successful identification. When the disturbance is measurable, however, it does not have to be removed if it can provide a positive contribution to identification. A constant disturbance was shown to slow down the identification speed. The best results will be obtained if one selects a DDR which removes only undesirable disturbances. In this technical brief, discrete series-parallel and parallel identification schemes for single-input, single-output systems were considered. The same principle, however, can be extended to other situations including the continuous time case and multi-input, and multi-output case. References 1 Astrom, K. J., and Eykhoff, P., "System Identification -A Survey," Automatica, Vol. 7, 1971, pp. 123-16

    Refined human artificial chromosome vectors for gene therapy and animal transgenesis

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    Human artificial chromosomes (HACs) have several advantages as gene therapy vectors, including stable episomal maintenance, and the ability to carry large gene inserts. We previously developed HAC vectors from the normal human chromosomes using a chromosome engineering technique. However, endogenous genes were remained in these HACs, limiting their therapeutic applications. In this study, we refined a HAC vector without endogenous genes from human chromosome 21 in homologous recombination-proficient chicken DT40 cells. The HAC was physically characterized using a transformation-associated recombination (TAR) cloning strategy followed by sequencing of TAR-bacterial artificial chromosome clones. No endogenous genes were remained in the HAC. We demonstrated that any desired gene can be cloned into the HAC using the Cre-loxP system in Chinese hamster ovary cells, or a homologous recombination system in DT40 cells. The HAC can be efficiently transferred to other type of cells including mouse ES cells via microcell-mediated chromosome transfer. The transferred HAC was stably maintained in vitro and in vivo. Furthermore, tumor cells containing a HAC carrying the suicide gene, herpes simplex virus thymidine kinase (HSV-TK), were selectively killed by ganciclovir in vitro and in vivo. Thus, this novel HAC vector may be useful not only for gene and cell therapy, but also for animal transgenesis

    Human RSPO1/R-spondin1 Is Expressed during Early Ovary Development and Augments β-Catenin Signaling

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    Human testis development starts from around 42 days post conception with a transient wave of SRY expression followed by up-regulation of testis specific genes and a distinct set of morphological, paracrine and endocrine events. Although anatomical changes in the ovary are less marked, a distinct sub-set of ovary specific genes are also expressed during this time. The furin-domain containing peptide R-spondin1 (RSPO1) has recently emerged as an important regulator of ovary development through up-regulation of the WNT/β-catenin pathway to oppose testis formation. Here, we show that RSPO1 is upregulated in the ovary but not in the testis during critical early stages of gonad development in humans (between 6–9 weeks post conception), whereas the expression of the related genes WNT4 and CTNNB1 (encoding β catenin) is not significantly different between these tissues. Furthermore, reduced R-spondin1 function in the ovotestis of an individual (46,XX) with a RSPO1 mutation leads to reduced β-catenin protein and WNT4 mRNA levels, consistent with down regulation of ovarian pathways. Transfection of wild-type RSPO1 cDNA resulted in weak dose-dependent activation of a β-catenin responsive TOPFLASH reporter (1.8 fold maximum), whereas co-transfection of CTNNB1 (encoding β-catenin) with RSPO1 resulted in dose-dependent synergistic augmentation of this reporter (approximately 10 fold). Furthermore, R-spondin1 showed strong nuclear localization in several different cell lines. Taken together, these data show that R-spondin1 is upregulated during critical stages of early human ovary development and may function as a tissue-specific amplifier of β-catenin signaling to oppose testis determination

    Transplantation directs oocyte maturation from embryonic stem cells and provides a therapeutic strategy for female infertility

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    Ten to 15% of couples are infertile, with the most common causes being linked to the production of few or no oocytes or sperm. Yet, our understanding of human germ cell development is poor, at least in part due to the inaccessibility of early stages to genetic and developmental studies. Embryonic stem cells (ESCs) provide an in vitro system to study oocyte development and potentially treat female infertility. However, most studies of ESC differentiation to oocytes have not documented fundamental properties of endogenous development, making it difficult to determine the physiologic relevance of differentiated germ cells. Here, we sought to establish fundamental parameters of oocyte development during ESC differentiation to explore suitability for basic developmental genetic applications using the mouse as a model prior to translating to the human system. We demonstrate a timeline of definitive germ cell differentiation from ESCs in vitro that initially parallels endogenous oocyte development in vivo by single-cell expression profiling and analysis of functional milestones including responsiveness to defined maturation media, shared genetic requirement of Dazl, and entry into meiosis. However, ESC-derived oocyte maturation ultimately fails in vitro. To overcome this obstacle, we transplant ESC-derived oocytes into an ovarian niche to direct their functional maturation and, thereby, present rigorous evidence of oocyte physiologic relevance and a potential therapeutic strategy for infertility

    Adaptive Pulse Width Control for Precise Positioning Under the Influence of Stiction and Coulomb Friction

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    For the robustness experiment, the friction is increased by increasing the sealing pressure. The PID control exhibits a large overshoot during the transient state, while the other controllers exhibit no overshoot, as shown in Figs. 4 and 5. In the SMC, errors are reduced very slowly and the steady-state error is relatively large as shown in Fig. 5. Settling times of the PID control, the TDC, and the TDSMC are 3.32 s, 2.96 s, and 1.94 s, respectively, as shown in Figs. 4{b) and 5(^). The PID control and the TDC perform very poorly and their settling times are increased by 90.8 and 105.6 percent, respectively, from their nominal values. On the other hand, the TDSMC performs very well and its settling time is increased only by 9 percent from the nominal value. Therefore, the TDSMC has the best performance robustness. Conclusions The TDSMC which is a combination of the TDC and the SMC is proposed for the system with unknown dynamics and disturbances. This method uses the idea of switching of the sliding mode control while reducing the chattering associated with it. Experiments on the position control of a DC motor system with stick-slip friction, were conducted to evaluate performances of the control algorithms. Experiments show that the TDSMC exhibits the best performance robustness and that the TDC and the TDSMC perform better than the PID control with an anti-windup filter and the integral sliding mode control. 227. Youcef-Touini, K., and Bobbet, J., 1991, "Stability of Uncertain Linear Systems With Time Delay," ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND CONTROL, Vol. 113, pp. 558-567. Youcef-Toumi, K., and Ito, O., 1990, "A Time Delay Controller for Systems With Unknown Dynamics," ASME JOURNAL OF DYNAMIC SYSTEMS, MEASURE- MENT, AND CONTROL, Vol. 112, Youcef-Toumi, K., and Reddy, S., 1992, "Analysis of Linear Time Invariant Systems With Time Delay," ASME JOURNAL OF DYNAMIC SYSTEMS, MEASURE- MENT, AND CONTROL, Vol. 114, Youcef-Toumi, K., and Wu, S.-T., 1992, "Input/Output Linearization Using Time Delay Control," ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND CONTROL, Vol. 114, pp. 10-19

    Multi -ancestry genome-wide association analyses identify novel genetic mechanisms in rheumatoid arthritis.

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    Rheumatoid arthritis (RA) is a highly heritable complex disease with unknown etiology. Multi-ancestry genetic research of RA promises to improve power to detect genetic signals, fine-mapping resolution and performances of polygenic risk scores (PRS). Here, we present a large-scale genome-wide association study (GWAS) of RA, which includes 276,020 samples from five ancestral groups. We conducted a multi-ancestry meta-analysis and identified 124 loci (P < 5 × 10−8), of which 34 are novel. Candidate genes at the novel loci suggest essential roles of the immune system (for example, TNIP2 and TNFRSF11A) and joint tissues (for example, WISP1) in RA etiology. Multi-ancestry fine-mapping identified putatively causal variants with biological insights (for example, LEF1). Moreover, PRS based on multi-ancestry GWAS outperformed PRS based on single-ancestry GWAS and had comparable performance between populations of European and East Asian ancestries. Our study provides several insights into the etiology of RA and improves the genetic predictability of RA.We thank the Director of Health Malaysia for supporting the work described in the South Asian (SAS) population: the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA) study. The MyEIRA study was funded by grants from Ministry of Health Malaysia (NMRR-08-820-1975) and the Swedish National Research Council (DNR-348-2009-6468). The GENRA study and the CARDERA genetics cohort genotyping were funded by Versus Arthritis (grant reference 19739 to I.C.S.). The Nurses’ Health Study (NHS cohort) is funded by the National Institutes of Health (NIH) (R01 AR049880, UM1 CA186107, R01 CA49449, U01 CA176726 and R01 CA67262). The Swedish EIRA study was supported by the Swedish Research Council (to L.K., L.P. and L.A.). S.S. was in part supported by the Mochida Memorial Foundation for Medical and Pharmaceutical Research, Kanae Foundation for the Promotion of Medical Science, Astellas Foundation for Research on Metabolic Disorders, JCR Grant for Promoting Basic Rheumatology, and Manabe Scholarship Grant for Allergic and Rheumatic Diseases. I.C.S. is funded by the National Institute for Health and Care Research (NIHR) Advanced Research Fellowship (grant reference NIHR300826). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. K.A.S. is supported by the Sherman Family Chair in Genomic Medicine and by a Canadian Institutes for Health Research Foundation Grant (FDN 148457) and grants from the Ontario Research Fund (RE-09-090) and Canadian Foundation for Innovation (33374). S.-C.B. is supported by the Basic Science Research Program through the NRF funded by the Ministry of Education (NRF-2021R1A6A1A03038899). R.P.K. and J.C.E. are funded by NIH (UL1 TR003096). C.M.L. is partly funded by the NIHR Maudsley Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London. T. Arayssi was partially supported by the National Priorities Research Program (grant 4-344-3-105 from the Qatar National Research Fund, a member of Qatar Foundation). M. Kerick and J.M. are funded by Rheumatology Cooperative Research Thematic Network program RD16/0012/0013 from the Instituto de Salud Carlos III (Spanish Ministry of Science and Innovation). Y.O. is funded by JSPS KAKENHI (19H01021 and 20K21834), AMED (JP21km0405211, JP21ek0109413, JP21ek0410075, JP21gm4010006 and JP21km0405217), JST Moonshot R&D (JPMJMS2021 and JPMJMS2024), Takeda Science Foundation, and the Bioinformatics Initiative of Osaka University Graduate School of Medicine. Y. Kochi is funded by grants from Nanken-Kyoten, TMDU and Medical Research Center Initiative for High Depth Omics. S.R. is supported by UH2AR067677, U01HG009379, R01AR063759 and U01HG012009
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