175 research outputs found
When Fewer Layers Break More Chains: Layer Pruning Harms Test-Time Scaling in LLMs
No full textLayer pruning has emerged as a widely adopted technique for improving the efficiency of large language models (LLMs). Although existing methods demonstrate strong performance retention on general knowledge tasks, their effect on long-chain reasoning, a more brittle yet crucial capability, remains largely unexplored. In this work, we study the impact of layer pruning on long-chain reasoning through the lens of test-time scaling, a key mechanism in modern LLMs that enables strong reasoning capacity by allocating more computation at inference time. With extensive experiments, we demonstrate that pruning even one or two layers can severely impair test-time scaling, with performance collapsing drastically on long reasoning benchmarks even when performance on knowledge-intensive and shallow reasoning tasks remains stable. Furthermore, we find that standard supervised fine-tuning remedies fail to recover test-time scaling once it has deteriorated. Through in-depth analyses, we identify the mechanisms underlying this fragility of test-time scaling and highlight the fundamental risks of applying layer pruning to reasoning-intensive LLMs. These findings call for a rethinking of layer pruning strategies and provide insights for developing methods that preserve the robustness of reasoning. We open-source the codebase in \href{https://github.com/keyu-wang-2002/Layer-Pruning-Harms-Inference-Scaling}{https://github.com/keyu-wang-2002/Layer-Pruning-Harms-Inference-Scaling}
The impact of the COVID-19 on the mobility of Chinese international students
No full textIn the context of the spread of the COVID-19 across the country, the global population flow has undergone tremendous changes, and the mobility and development trends of international students have also undergone important changes. As China is the main provider of international students, millions of international students and those who are planning to study must delay or interrupt their study abroad plans. In previous studies, international education research on Chinese students as an example has very important reference value. Many articles and data have analyzed the trend of Chinese students' global flow. However, due to the impact of the epidemic, this trend will inevitably not develop in the expected direction, or even decline rapidly. At present, countries around the world have opened their border policies and resumed normal life, but the epidemic has not updated the trend and reasons for the flow of international students in time. What are the factors that will affect the mobility of international students after the end of the COVID-19? The purpose of Chinese students choosing to study abroad Did local preferences matter.
In this article, we will conduct quantitative research on those who intend to study abroad in mainland China to gain an extensive and in-depth understanding of the changing trends and factors of the flow of international students in mainland China in the post-epidemic era.
A push-pull model helps explain changing trends in international student mobility in the context of the COVID-19 pandemic. The outbreak has created new drivers, such as health and safety concerns, travel restrictions and economic recession. These factors have forced many international students to postpone or interrupt their study abroad plans.
Human capital theory, on the other hand, emphasizes the role of education in enhancing the skills and knowledge of individuals, thereby increasing their economic productivity, and earning potential. From this perspective, studying abroad can be seen as an investment in human capital that has the potential to bring long-term benefits to individuals and society.
In the study, we found that the COVID-19 epidemic has accelerated changes in the flow structure of international students and exacerbated educational inequality; secondly, during the COVID-19 epidemic, Chinese students have suffered certain discrimination overseas, and the selection factors in the destination country for studying abroad In the end, due to the blockade policies adopted by countries in the coronavirus, a new online teaching model has emerged, and this model has also had a certain impact on the global education system after the COVID
On-demand In-vivo Long-term Stem Cell Tracking using Bright Ferritin Magnetic Resonance Imaging
No full textStem cell therapy is an emerging therapeutic paradigm in regenerative medicine, with the putative ability to replace, repair, or regenerate any tissues or organs in the body. Yet, obstacles remain to the success of stem cell therapies, one of which is the limited ability to probe cell fate and intervene after cells have been transplanted into the body. An imaging technology that enables non-invasive cell tracking in deep tissue would address these hurdles and pave the way for stem cell treatment optimization and translation. Magnetic resonance imaging (MRI) is the most versatile imaging modality that exhibits high spatial resolution, excellent soft tissue contrast, unlimited tissue penetration, and freedom from ionizing radiation. Currently, the only solution to achieve long-term cell tracking is to use a reporter gene strategy that incorporates the transgene into the genome of the cell population. However, MRI reporter genes described to date yield low sensitivity of detection. Recently, our lab proposed a novel bright ferritin MRI cell tracking platform that overcomes the limited sensitivity and specificity of conventional dark ferritin mechanism. This approach uses gene editing to overexpress the iron-storage protein, ferritin, in the cells of interest and utilizes manganese metal to form intracellular ferritin-manganese nanoparticles that confer a bright contrast on MRI.In this body of work, we develop and demonstrate the utility of the bright ferritin MRI cell tracking platform for monitoring stem cell therapies. We applied this imaging technology to human embryonic stem cells (hESCs), human embryonic stem cell-derived cardiomyocytes (hESC-CMs), and human neural progenitor cells (hNPCs), with the context of their therapeutic potential in repairing damaged heart or spinal cord. Stem cells overexpressing the ferritin transgene displayed normal cell functions. Bright ferritin MRI enabled non-invasive monitoring of 1) hESC survival, proliferation, and teratoma formation in the mouse leg muscle, 2) hESC-CM survival and distribution in the infarcted rat heart, and 3) hNPC survival and migration in the injured rat spinal cord. This thesis demonstrated the feasibility of bright ferritin MRI to track stem cells with high sensitivity, on demand, and longitudinally, serving as an imaging tool for graft assessment and therapeutic evaluation in stem cell therapies.Ph.D
Challenges in Accessing Community-Based Rehabilitation and Long-Term Care for Older Adult Stroke Survivors and Their Caregivers: A Qualitative Study
Get PDFSining Zeng,1,2,* Min Wu,1,* Ling Xu,1 Zining Guo,1 Shufan Chen,1 Keyu Ling,1 Haihan Li,1 Xiaoli Yu,1 Xiaoping Zhu1 1Department of Nursing, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, 200072, People’s Republic of China; 2School of Nursing, Soochow University, Suzhou, 215031, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaoping Zhu, Department of Nursing, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, 200072, People’s Republic of China, Tel +86-021-66300588, Fax +86-021-66307542, Email [email protected] and Objectives: While extensive research has examined the rehabilitation challenges faced by stroke survivors, there is limited literature addressing the difficulties encountered by older adult stroke survivors and their caregivers in accessing rehabilitation and long-term care within the Chinese community. This study aimed to investigate the specific challenges related to access, quality, and coordination of rehabilitation and long-term care experienced by older adult stroke survivors and their caregivers within the Chinese community.Methods: A qualitative phenomenological design was employed to explore the lived experiences of stroke survivors and their caregivers within the Chinese community. A purposive sampling method was used to recruit participants from June to August 2023. Participants engaged in face-to-face semi-structured interviews. The data were analyzed using an inductive thematic analysis approach to identify and understand key themes and sub-themes.Results: The study involved 38 participants, consisting of 21 older adult stroke survivors (13 males, 8 females) and 17 family caregivers (7 males, 10 females), recruited from five Chinese community health service stations. The analysis identified four distinct themes and 11 sub-themes that encapsulated the challenges faced by participants. These themes include (1) Difficulties in accessing medical services (insufficient medical resources, lack of rehabilitation resources, and time-consuming processes), (2) Challenges in daily life (inconvenience in daily mobility, inadequate financial support, and difficulties in applying for home care services), (3) Psychosocial stress (loneliness, powerlessness, and worry about burdening others), (4) Insufficient information (lack of awareness of available community services, and limited public health education activities).Conclusion: Older adult stroke survivors and their caregivers in Chinese communities face significant challenges. To improve their well-being and quality of life, it is crucial to address these challenges through enhanced access to healthcare, better support for daily living, and more effective information dissemination. Meeting these needs requires a coordinated effort from healthcare providers, community stakeholders, and policymakers to develop and implement effective, long-term care solutions.Keywords: stroke, survivors, caregivers, community, qualitative researc
Predictive role of the prognostic nutritional index for long-term prognosis among patients undergoing pancreatoduodenectomy: a meta-analysis
No full textAbstract Purpose To identify the predictive role of the preoperative prognostic nutritional index (PNI) for long-term survival in patients undergoing pancreatoduodenectomy. Methods The PubMed, EMBASE, Web of Science, Cochrane Library and CNKI databases were searched up to October 28, 2024. The primary outcomes included overall survival (OS) and disease-free survival (DFS). Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated, and subgroup analyses by country, type of cancer and source of HR were performed. Results Fifteen studies with 2106 patients were included. The pooled results demonstrated that a lower preoperative PNI was related to poorer OS (HR = 1.60, 95% CI: 1.38–1.86, P < 0.001) and DFS (HR = 1.44, 95% CI: 1.00–2.07, P = 0.051). Subgroup analysis stratified by country (China vs. non-China), type of cancer (pancreatic cancer vs. nonpancreatic cancer vs. mixed) and source of HR (univariate vs. multivariate analysis) revealed similar results. Conclusion On the basis of the available evidence, the preoperative PNI might serve as a novel prognostic indicator in patients undergoing pancreatoduodenectomy, with a lower PNI predicting worse survival. However, more high-quality studies are needed to further verify the above findings
Author response image 1. Author response
No full textAnkyrin adaptors together with their spectrin partners coordinate diverse ion channels and cell adhesion molecules within plasma membrane domains and thereby promote physiological activities including fast signaling in the heart and nervous system. Ankyrins specifically bind to numerous membrane targets through their 24 ankyrin repeats (ANK repeats), although the mechanism for the facile and independent evolution of these interactions has not been resolved. Here we report the structures of ANK repeats in complex with an inhibitory segment from the C-terminal regulatory domain and with a sodium channel Nav1.2 peptide, respectively, showing that the extended, extremely conserved inner groove spanning the entire ANK repeat solenoid contains multiple target binding sites capable of accommodating target proteins with very diverse sequences via combinatorial usage of these sites. These structures establish a framework for understanding the evolution of ankyrins' membrane targets, with implications for other proteins containing extended ANK repeat domains.</p
Ji yu jin chang sheng xue xuan fu de zi yun xing he zi fu dong er wei zhi dong qi
No full textM.Phil.Acoustic radiation force in the near-field of a vibrating source can be utilized to lift and transport objects, which provides a non-contact driving technology in addition to maglev. This research presents a novel self-running planar motion stage utilizing near-field acoustic transportation phenomenon and coupled resonant vibration of the device.Finite element analysis models have been established to find the needed resonant modes and optimize the design of the structure. The first longitudinal and the second bending modes are designed to have an identical frequency to create elliptical vibration of the structure, which can provide vertical levitation force as well as the propulsion force. A dynamic model based on the Reynolds Equation has been established to study the levitation and driving mechanism of the proposed device. The levitation and driving forces are analyzed; and the relationship between the driving force and the input phase difference is investigated to optimize the following position control. A capacitance surface encoder is proposed to provide the levitation height and two dimensional position feedback for the stage. The encoder design is based on the measurement of capacitance change between the driving stage and the metal sensing plates embedded in the ground. The lateral position (in the XY plane) of the circular stage can be uniquely determined based on the capacitance values.A prototype including the stage, encoder, and controller is implemented and characterized to demonstrate the performance of the proposed design. Two motion characteristics of the stage are first tested: one is the influence of the excitation voltage amplitude on the levitation height, and the other is the influence of the amplitude and phase angles of the excitation signals on the velocity and thrust force. In the calibration of the encoder, the calculated coordinates are firstly compensated for the scaling and the misalignment of the encoder axis and the precision stage. And the systematic errors from the nonlinear features are identified and fitted to a third-order polynomial equation in each axis. In the control scheme, the capacitance encoder works as the feedback module, and a LabVIEW program is used for date acquisition and processing. The stage is tested and demonstrated to follow a circular trajectory with a radius of 3.5mm.This work investigates a novel self-floating and self-running two-dimensional actuator using near-field acoustic levitation and coupled resonant vibration of the device. Compared with the conventional designs based on near-field acoustic levitation, the proposed design eliminates any external component such as guide rail, which contributes to bigger working space. This design also has two-dimensional motion capability with higher load capacity and energy efficiency. A dynamic model based on the Reynolds Equation is established to study the driving mechanism. A capacitance surface encoder is proposed to provide the two dimensional position feedback for the stage. A prototype including the stage, encoder, and controller is implemented and characterized to demonstrate the capability of the proposed design.振動源在近場中產生的輻射力可以用於提升和運輸物體，這現象可用於非接觸驅動技術，並有別於磁懸浮技術。本研究提出了一種新型的自運行平面運動機構，該機構利用了近場聲學傳播現象和裝置的耦合諧振。通過有限元分析可以找到機構的共振模態，並且用於指導結構的優化設計。通過結構設計，使得一階縱向模態和二階橫向模態具有相同的振動頻率，以產生橢圓振動，橢圓振動同時提供懸浮立和前進驅動力。建立了基於雷諾方程的運動模型，來分析機構的懸浮和運動機制。通過分析懸浮力和驅動力，獲得驅動力與輸入信號相位差之間的關係，用於之後定位平臺的位置控制。基於表面電容的編碼器被用於定位平臺的位置反饋，這個反饋包括了平臺的懸浮高度以及它的二維平面位置。編碼器可以測量懸浮平臺和固定在地上的金屬感應板間的電容。基於測得的電容值，通過相應的計算，可以得出平臺在XY平面內的確定位置。建立了包括運動器，編碼器和控制器在內的實驗模型，用於驗證設計的性能。首先是關於驅動器運動性能的測定，第一個是電壓大小對懸浮高度的影響，第二個是電壓大小以及電壓相位角對於運動速度和驅動力的影響。在編碼器的校準過程中，首先補償了由於編碼器和精密平臺錯位以及縮放而引起的誤差， 然後運用三階多項式來擬合每個軸的非線性系統誤差。在控制方案中，電容式編碼器起反饋作用，一個LabVIEW程序用於對電信號的處理。在運動測試中，平臺行走了一個半徑為3.5mm的圓形軌跡。這項研究成功研發了一種新型的自懸浮和自運動的二維運動機構，這個機構運用了近場超聲懸浮和耦合共振效應。與傳統的近場超聲懸浮裝置相比，新的設計不需要導軌之類的任何外部部件，這有助於提供更大的工作空間。該設計具有二維運動能力，並有更高的負載能力和能量效率。建立了基於雷諾方程的運動模型來研究其運動機制。用電容編碼器來當作二維定位平臺的位置反饋。包括運動機構，編碼器和控制器在內的實驗模型被建立，用於驗證設計的性能。Chen, Keyu.Thesis M.Phil. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves 56-60).Abstracts also in Chinese.Title from PDF title page (viewed on 06, February, 2020).Chen, Keyu
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