Disclosure of Unknown Harms in Magnetic Resonance Imaging Research

Unknown harms are by their nature difficult to communicate. While magnetic resonance imaging (MRI) has known risks (e.g., metal projectiles, dislodgement of medical implants), this imaging modality also has potential unknown long-term negative health effects associated with its static magnetic fields. We carried out a research ethics board (REB) file review of previously approved MRI research studies and found that unknown risks were either left undisclosed or were inadequately disclosed to research participants and REBs. This article outlines issues raised by our REB file review and suggests steps that should be taken in order to satisfactorily communicate information about potential unknown harms of MRI.     

低功耗高频小信号放大器设计

本文根据高频调谐放大器原理设计了一个低功耗高频小信号放大器,该设计方案由电源电路,衰减电路以及主要的LC谐振放大电路三部分组成,并利用其它辅助工具完成了该电路的调试工作,调试结果表明该低功耗高频小信号放大器有效解决了放大电路中经常出现的自激振荡问题,难以准确的调谐问题以及实现放大器与前后级的阻抗匹配问题.从而实现了快速、有效的分析和制作高频放大器,使LC谐振放大器达到低压,低功耗的设计要求.     

Multivariate functional response low‐rank regression with an application to brain imaging data

We propose a multivariate functional response low‐rank regression model with possible high‐dimensional functional responses and scalar covariates. By expanding the slope functions on a set of sieve bases, we reconstruct the basis coefficients as a matrix. To estimate these coefficients, we propose an efficient procedure using nuclear norm regularization. We also derive error bounds for our estimates and evaluate our method using simulations. We further apply our method to the Human Connectome Project neuroimaging data to predict cortical surface motor task‐evoked functional magnetic resonance imaging signals using various clinical covariates to illustrate the usefulness of our results.     

共鸣与借鉴：玛拉沁夫与肖洛霍夫的艺术情缘

相似的人生经历与同样深厚的草原情怀,使玛拉沁夫对肖洛霍夫产生了异乎寻常的亲近感。《茫茫的草原》就是他借鉴肖洛霍夫创作艺术的成功范例。无论是在情节安排、风土人情与景物描写,还是在抒情方式与人物刻画等方面,都可看出它与《静静的顿河》之间的亲缘关系。同时,它身上还带有《新垦地》中的某些艺术痕迹。     

短柱耦合结构固体源

本文提出一种新型偏置结构的毫米波固体源—短柱耦合结构.该结构的特点是便于调试,适应于参般离散性较大的负阻器件.运用谐振腔理论解释了该结构同通常的拉耦合结构相比具有较好的克服横向同轴谐振干扰能力.在 ka 波段对机调和电调源的实际调试获取较宽的调谐特性.     

关于p-凸泛函族的共鸣定理

共鸣定理是泛函分析中重要的基础定理之一,其形式也有多种变化。在[1]—[5]中讨论了一类共鸣定理,即所谓凸泛函族的共鸣定理。由于凸分析的广泛运用性,凸性的概念有必要进一步推广。本文首先给出p-凸性的概念,p-凸集和p-凸泛函具有完全类似于凸集和凸泛函的性质,然后导出了在拓扑向量空间及赋范空间中p-凸泛函族的几个共鸣定理,推广了文[1]—[5]中的相应结果。     

Cognition in Situations

The symbolic interactionist tradition can contribute to advancing sociological studies of cognition by setting dual process models on more solid ground. I draw on Blumer's epistemological statements and the interactionist tradition more broadly to consider how dual process models of cognition could be applied to naturally occurring situations. I suggest that attending to the ways the past and the future are handled and modified within social interaction provides a usable inroad for the sociology of cognition to engage with situational analysis. I identify “resonance” and “iterative reprocessing” as concepts that are suitable to this end.     

Nonlinear voxel-based modelling of the haemodynamic response in fMRI

A common assumption for data analysis in functional magnetic resonance imaging is that the response signal can be modelled as the convolution of a haemodynamic response (HDR) kernel with a stimulus reference function. Early approaches modelled spatially constant HDR kernels, but more recently spatially varying models have been proposed. However, convolution limits the flexibility of these models and their ability to capture spatial variation. Here, a range of (nonlinear) parametric curves are fitted by least squares minimisation directly to individual voxel HDRs (i.e., without using convolution). A ‘constrained gamma curve’ is proposed as an efficient form for fitting the HDR at each individual voxel. This curve allows for spatial variation in the delay of the HDR, but places a global constraint on the temporal spread. The approach of directly fitting individual parameters of HDR shape is demonstrated to lead to an improved fit of response estimates.     

谈歌唱中共呜的构成与运用

本文论述了歌唱共鸣器官的构成及其在声乐演唱中的重要作用，探讨了共鸣与音源、音色的关系及共鸣腔体的训练。从理论角度深入了解共鸣的构成和运用，将会对我们的演唱和教学起到重要作用。     

Functional and dynamic magnetic resonance imaging using vector adaptive weights smoothing

We consider the problem of statistical inference for functional and dynamic magnetic resonance imaging (MRI). A new approach is proposed which extends the adaptive weights smoothing procedure of Polzehl and Spokoiny that was originally designed for image denoising. We demonstrate how the adaptive weights smoothing method can be applied to time series of images, which typically occur in functional and dynamic MRI. It is shown how signal detection in functional MRI and the analysis of dynamic MRI can benefit from spatially adaptive smoothing. The performance of the procedure is illustrated by using real and simulated data.