268 research outputs found

    The apterous endemic genus Omphra Dejean (Coleoptera: Carabidae: Helluonini) of the Indian subcontinent : taxonomy with notes on habits and distributional patterns

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    Among the four oriental genera of the tribe Helluonini, Omphra Dejean (Coleoptera: Carabidae), is unique for its endemism to the Indian subcontinent and aptery. High intraspecies variability in morphological characters and limited diagnostic information makes species differentiation of the genus Omphra a complicated task. The present study provides a description of a new species, Omphra drumonti n. sp. from the Western Ghats, redescriptions and a key to the species of Omphra, details of intraspecies variation, discussion of relationships between taxa and distributional patterns of the genus. Based on the distributional patterns in the Indian subcontinent and flightlessness of the genus, inability to cross the physical barrier of the Ganges–Brahmaputra delta between north and peninsular India is indicated as the reason for its absence in the northeastern Indian subcontinent and endemism to the lower Indian subcontinent

    Essays on family structures, education, health and well-being in old age in China

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    The first chapter investigates the health and social impacts of a new pension system in China. China initiated the new rural pension scheme targeting the large rural population in 2009. This new scheme was claimed to be a huge improvement to the previous welfare institution and a strong defense to rural people's elderly life. Using panel data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), I apply the PSM-DID approach to identify causal relationships between the pension and multiple covariates at the individual level. I have found that the pension significantly reduced systolic and diastolic pressures, as well as improved overall health and life quality of participants. I acknowledge the positive influences of China's new rural pension on elderly life of the rural population, and discuss potential directions for future research.The second chapter explores the impacts of co-residing grandparents on children from a Chinese perspective. The matrilateral bias hypothesis (MBH) implies that children may expect more supports from their maternal grandparents. Nevertheless, the current literature has not shed much light on how different genders are affected by grandparental lineage under the multi-generational coresidence context. In this chapter, I document and discuss lineage heterogeneity of grandparental impacts on grandchildren, and as well explore whether girls benefit more from the maternal grandparents than boys do. To resolve endogeneity bias where the standard IV approach is infeasible, I fit panel data from the China Family Panel Studies (CFPS) into a fixed effects model and then apply the heteroskedasticity-based instruments of Lewbel (2012) as a robustness check. The results suggest that compared to direct interaction with co-residing grandparents, grandchildren are more likely to be influenced through parents. There are no consistent evidences for the MBH found

    Local generation of hydrogen for enhanced photothermal therapy.

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    By delivering the concept of clean hydrogen energy and green catalysis to the biomedical field, engineering of hydrogen-generating nanomaterials for treatment of major diseases holds great promise. Leveraging virtue of versatile abilities of Pd hydride nanomaterials in high/stable hydrogen storage, self-catalytic hydrogenation, near-infrared (NIR) light absorption and photothermal conversion, here we utilize the cubic PdH0.2 nanocrystals for tumour-targeted and photoacoustic imaging (PAI)-guided hydrogenothermal therapy of cancer. The synthesized PdH0.2 nanocrystals have exhibited high intratumoural accumulation capability, clear NIR-controlled hydrogen release behaviours, NIR-enhanced self-catalysis bio-reductivity, high NIR-photothermal effect and PAI performance. With these unique properties of PdH0.2 nanocrystals, synergetic hydrogenothermal therapy with limited systematic toxicity has been achieved by tumour-targeted delivery and PAI-guided NIR-controlled release of bio-reductive hydrogen as well as generation of heat. This hydrogenothermal approach has presented a cancer-selective strategy for synergistic cancer treatment

    Training Overparametrized Neural Networks in Sublinear Time

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    The success of deep learning comes at a tremendous computational and energy cost, and the scalability of training massively overparametrized neural networks is becoming a real barrier to the progress of artificial intelligence (AI). Despite the popularity and low cost-per-iteration of traditional backpropagation via gradient decent, stochastic gradient descent (SGD) has prohibitive convergence rate in non-convex settings, both in theory and practice. To mitigate this cost, recent works have proposed to employ alternative (Newton-type) training methods with much faster convergence rate, albeit with higher cost-per-iteration. For a typical neural network with m=poly(n)m=\mathrm{poly}(n) parameters and input batch of nn datapoints in Rd\mathbb{R}^d, the previous work of [Brand, Peng, Song, and Weinstein, ITCS'2021] requires mnd+n3\sim mnd + n^3 time per iteration. In this paper, we present a novel training method that requires only m1αnd+n3m^{1-\alpha} n d + n^3 amortized time in the same overparametrized regime, where α(0.01,1)\alpha \in (0.01,1) is some fixed constant. This method relies on a new and alternative view of neural networks, as a set of binary search trees, where each iteration corresponds to modifying a small subset of the nodes in the tree. We believe this view would have further applications in the design and analysis of deep neural networks (DNNs)

    A Faster kk-means++ Algorithm

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    K-means++ is an important algorithm to choose initial cluster centers for the k-means clustering algorithm. In this work, we present a new algorithm that can solve the kk-means++ problem with near optimal running time. Given nn data points in Rd\mathbb{R}^d, the current state-of-the-art algorithm runs in O~(k)\widetilde{O}(k ) iterations, and each iteration takes O~(ndk)\widetilde{O}(nd k) time. The overall running time is thus O~(ndk2)\widetilde{O}(n d k^2). We propose a new algorithm \textsc{FastKmeans++} that only takes in O~(nd+nk2)\widetilde{O}(nd + nk^2) time, in total

    Query Complexity of Active Learning for Function Family With Nearly Orthogonal Basis

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    Many machine learning algorithms require large numbers of labeled data to deliver state-of-the-art results. In applications such as medical diagnosis and fraud detection, though there is an abundance of unlabeled data, it is costly to label the data by experts, experiments, or simulations. Active learning algorithms aim to reduce the number of required labeled data points while preserving performance. For many convex optimization problems such as linear regression and pp-norm regression, there are theoretical bounds on the number of required labels to achieve a certain accuracy. We call this the query complexity of active learning. However, today's active learning algorithms require the underlying learned function to have an orthogonal basis. For example, when applying active learning to linear regression, the requirement is the target function is a linear composition of a set of orthogonal linear functions, and active learning can find the coefficients of these linear functions. We present a theoretical result to show that active learning does not need an orthogonal basis but rather only requires a nearly orthogonal basis. We provide the corresponding theoretical proofs for the function family of nearly orthogonal basis, and its applications associated with the algorithmically efficient active learning framework

    Don't Ignore Dual Logic Ability of LLMs while Privatizing: A Data-Intensive Analysis in Medical Domain

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    Extensive studies have been devoted to privatizing general-domain Large Language Models (LLMs) as Domain-Specific LLMs via feeding specific-domain data. However, these privatization efforts often ignored a critical aspect: Dual Logic Ability, which is a core reasoning ability for LLMs. The dual logic ability of LLMs ensures that they can maintain a consistent stance when confronted with both positive and negative statements about the same fact. Our study focuses on how the dual logic ability of LLMs is affected during the privatization process in the medical domain. We conduct several experiments to analyze the dual logic ability of LLMs by examining the consistency of the stance in responses to paired questions about the same fact. In our experiments, interestingly, we observed a significant decrease in the dual logic ability of existing LLMs after privatization. Besides, our results indicate that incorporating general domain dual logic data into LLMs not only enhances LLMs' dual logic ability but also further improves their accuracy. These findings underscore the importance of prioritizing LLMs' dual logic ability during the privatization process. Our study establishes a benchmark for future research aimed at exploring LLMs' dual logic ability during the privatization process and offers valuable guidance for privatization efforts in real-world applications

    Large Language Models Are Semi-Parametric Reinforcement Learning Agents

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    Inspired by the insights in cognitive science with respect to human memory and reasoning mechanism, a novel evolvable LLM-based (Large Language Model) agent framework is proposed as REMEMBERER. By equipping the LLM with a long-term experience memory, REMEMBERER is capable of exploiting the experiences from the past episodes even for different task goals, which excels an LLM-based agent with fixed exemplars or equipped with a transient working memory. We further introduce Reinforcement Learning with Experience Memory (RLEM) to update the memory. Thus, the whole system can learn from the experiences of both success and failure, and evolve its capability without fine-tuning the parameters of the LLM. In this way, the proposed REMEMBERER constitutes a semi-parametric RL agent. Extensive experiments are conducted on two RL task sets to evaluate the proposed framework. The average results with different initialization and training sets exceed the prior SOTA by 4% and 2% for the success rate on two task sets and demonstrate the superiority and robustness of REMEMBERER
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