418 research outputs found

    Curriculum Learning and Imitation Learning for Model-free Control on Financial Time-series

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    Curriculum learning and imitation learning have been leveraged extensively in the robotics domain. However, minimal research has been done on leveraging these ideas on control tasks over highly stochastic time-series data. Here, we theoretically and empirically explore these approaches in a representative control task over complex time-series data. We implement the fundamental ideas of curriculum learning via data augmentation, while imitation learning is implemented via policy distillation from an oracle. Our findings reveal that curriculum learning should be considered a novel direction in improving control-task performance over complex time-series. Our ample random-seed out-sample empirics and ablation studies are highly encouraging for curriculum learning for time-series control. These findings are especially encouraging as we tune all overlapping hyperparameters on the baseline -- giving an advantage to the baseline. On the other hand, we find that imitation learning should be used with caution.Comment: AAAI 2024 AI4TS Workshop Ora

    Manipulation of Rat Movement via Nigrostriatal Stimulation Controlled by Human Visually Evoked Potentials

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    Here, we report that the development of a brain-to-brain interface (BBI) system that enables a human user to manipulate rat movement without any previous training. In our model, the remotely-guided rats (known as ratbots) successfully navigated a T-maze via contralateral turning behaviour induced by electrical stimulation of the nigrostriatal (NS) pathway by a brain-computer interface (BCI) based on the human controller's steady-state visually evoked potentials (SSVEPs). The system allowed human participants to manipulate rat movement with an average success rate of 82.2% and at an average rat speed of approximately 1.9 m/min. The ratbots had no directional preference, showing average success rates of 81.1% and 83.3% for the left-and right-turning task, respectively. This is the first study to demonstrate the use of NS stimulation for developing a highly stable ratbot that does not require previous training, and is the first instance of a training-free BBI for rat navigation. The results of this study will facilitate the development of borderless communication between human and untrained animals, which could not only improve the understanding of animals in humans, but also allow untrained animals to more effectively provide humans with information obtained with their superior perception.11Ysciescopu

    Coexistence of a Carotid Body Tumor and Thyroglossal Duct Carcinoma With Cervical Lymph Node Metastasis

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    Thyroglossal duct carcinoma is uncommon, occurring in approximately 1% of all thyroglossal duct remnants. This rare neoplasm is characterized by relatively nonaggressive behavior with infrequent lymph nodal spread. Another rare neoplasm of the head and neck region is a carotid body tumor. A 78-year-old woman with a 3-year history of midline and bilateral neck masses was referred to us. Fine needle aspiration biopsies and a computed tomography scan suggested the diagnosis of thyroglossal duct carcinoma with cervical lymph node metastasis. Interestingly, the left-side neck mass was found to be splaying the carotid bifurcation, on computed tomography imaging. Carotid arteriography demonstrated a highly vascular mass in the bifurcation of the carotid artery that was compressing the internal and external carotid arteries. To our knowledge, this is the first reported instance of a thyroglossal duct carcinoma with neck metastasis accompanied by a carotid body tumor. In addition, the carotid body tumor in this case mimicked neck metastasis from the thyroglossal duct carcinoma

    Safety Evaluation of Yukmijihwang-tang: Assessment of Acute and Subchronic Toxicity in Rats

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    Yukmijihwang-tang (YMJ; Liu wei di huang tang (China), Rokumigan (Japan)) has been used in the treatment of diseases including renal disorder, cognitive vitality, and diabetes mellitus. However, there is very little information regarding the toxicity of YMJ to give an assurance of safety for clinical treatment. To provide safety information for YMJ, we evaluated its acute and sub-chronic toxicity in rats. The single-dose toxicity of YMJ was examined using Sprague-Dawley rats. Rats were treated with YMJ extract orally at 0, 500, 1000, or 2000 mg/kg body weight. After a single administration, clinical signs were observed every day for two weeks, and body weights were measured five times, including an initial measurement on day 1 (the day of administration). In the sub-chronic oral toxicity study, YMJ was administered to rats at 0, 500, 1000, or 2000 mg/kg/day for 13 weeks. Mortalities, clinical signs, body weight changes, food and water consumption, ophthalmologic findings, urinalysis, hematological and biochemical parameters, gross findings, organ weights, and histological examination were monitored during the study period. We found no mortality and no abnormalities in clinical signs, body weights, and necropsy findings for any of the animals in the acute and sub-chronic studies following oral administration in the rat at up to 2000 mg/kg/day YMJ. YMJ may not have any single-dose toxicity; the LD50 of YMJ was over 2000 mg/kg, and it is safe for rats. The no-observed-adverse-effect-level (NOAEL) was considered to be 2000 mg/kg/day

    Endoscopic Thyroidectomy via an Axillo-Breast Approach without Gas Insufflation for Benign Thyroid Nodules and Micropapillary Carcinomas: Preliminary Results

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    PURPOSE: To examine the feasibility of endoscopic thyroidectomy (ET) via an axillo- breast approach without gas insufflation for large thyroid tumors and micropapillary carcinomas. MATERIALS AND METHODS: The patients in the benign group were separated into groups 1 (n=95, <4 cm in tumor diameter) and 2 (n=37, ≥4 cm in tumor diameter). Also, 57 patients in the micropapillary carcinoma group underwent an endoscopic hemithyroidectomy (HT) (group 3) and were compared with 60 patients who received conventional open HT (group 4). Postoperative functional outcome, local complications, surgical outcomes, and pathological outcomes were compared between the groups. RESULTS: In the benign group, there was no significant difference in mean operating time, hospital stay, or overall perioperative complications between the two groups. In the micropapillary carcinoma group, mean operating time and hospital stay in group 3 were significantly longer than in group 4 (p=0.015 and p≤0.001). The overall perioperative complications did not differ significantly between the groups. The postoperative cosmetic result was better in groups 1-3 (endo group) than in group 4 (open group). CONCLUSION: ET via a gasless axillo-breast approach seems to be a safe procedure even for benign thyroid lesions ≥4 cm and micropapillary carcinomas. Although it has the advantage of better cosmetic results over open thyroidectomy, there is room for improvement in terms of lessening its invasiveness and shortening the operative time.ope

    A Case of Dysplastic Nevus of the External Auditory Canal Presenting with Conductive Hearing Loss

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    A nevus which is a benign melanocytic neoplasm rarely occurs within the external auditory canal (EAC). A dysplastic nevus presents atypical features both clinically and histologically, and is important as a potential precursor for melanoma. We present a case of a 33-year-old female patient with a dysplastic nevus in her EAC. Physical examination revealed a protruding mass arising from the posterior wall of the left cartilaginous EAC. The mass showed clinically characteristic findings of a melanocytic nevus. The patient underwent excisional biopsy via a transcanal approach under local anesthesia. Histopathological examination revealed an intradermal nevus with atypical melanocytes without pleomorphism. There was no evidence of recurrence two years after surgical excision

    Traumatic Entrapment of the Vertebrobasilar Junction Due to a Longitudinal Clival Fracture: A Case Report

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    Vertebrobasilar junction entrapment due to a clivus fracture is a rare clinical observation. The present case report describes a 54-yr-old man who sustained a major craniofacial injury. The patient displayed a stuporous mental state (Glasgow Coma Scale [GCS]=8) and left hemiparesis (Grade 3). The initial computed tomography (CT) scan revealed a right subdural hemorrhage in the frontotemporal region, with a midline shift and longitudinal clival fracture. A decompressive craniectomy with removal of the hematoma was performed. Two days after surgery, a follow-up CT scan showed cerebellar and brain stem infarction, and a CT angiogram revealed occlusion of the left vertebral artery and entrapment of vertebrobasilar junction by the clival fracture. A decompressive suboccipital craniectomy was performed and the patient gradually recovered. This appears to be a rare case of traumatic vertebrobasilar junction entrapment due to a longitudinal clival fracture, including a cerebellar infarction caused by a left vertebral artery occlusion. A literature review is provided

    Crossed Cerebellar Diaschisis in Cerebral Infarction: Correlation of SPECT and Clinical Features

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    Patients with supratentorial cerebral infarction frequently show depressed metabolic activity in the contralateral cerebellar hemisphere which is known as crossed cerebellar diaschtsisfCt.D). In order to investigate the relationship between this phenomenon and the characteristics of the supratentorial lesion, we retrospectively evaluated the findings of 99mTc-HMPAO single photon emission computed tomography(SPECT) in 26 patients with a single supratentorial infarction lesion. A cerebellar asymmetry index (AIcbll), percent difference between both cerebellar hemispherestzx'Scbll],SPECT volume deficit (SVD), and magnetic resonance volume deficit (MVD) were quantitated. A CCD, defined as AIcbll >12%, was observed in 12 of the 26 patients (46.2%). No correlation was found between the ~%cbll and duration of disease, SVD, or MVD. SVD and MVD values showed no significant difference between CCD positive and negative groups (71+47ml \IS. 70+68ml and 90+84ml \IS. 67+77ml, respectively). Patients with frontoparietal lobe or deep middle cerebral artery territory infarctions showed a significantly higher incidence of CCD and lower ~%cbll values. Patients with severe hemiparesis had a higher incidence of CCD and lower ~%cbll values than those with milder or no hemiparesis (incidence, 5/5 \IS. 6/18, p=0.008; ~ %cbll,-21. 4+3.8% \IS -8. 3±11. 1%, p=O. 014). None of the 12 patients with CCD showed clinical signs of cerebellar dysfunction. In conclusion, the location rather than the extent of the lesion appears to be the major determinant for the occurrence and magnitude of CCD in stroke patients

    Successful Endourologic Management of Lower Pole Moiety Ureteropelvic Junction Obstruction in a Partially Duplicated Collecting System

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    We present two cases of symptomatic lower pole moiety ureteropelvic junction obstruction (UPJO) in a partially duplicated collecting system that were successfully treated with minimally invasive endourologic procedures. In the first case, we performed retrograde endopyelotomy with the Acucise® ureteral cutting balloon device, and in the latter case, we performed percutaneous nephrolithotomy and antegrade endopyelotomy because of the presence of multiple renal stones. Subsequent intravenous pyelography confirmed marked resolution of the obstruction, and both patients remained asymptomatic during 1 year of follow-up
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