Perioperative Bevacizumab-based Triplet Chemotherapy in Patients With Potentially Resectable Colorectal Cancer Liver Metastases

Background

In colorectal cancer liver metastases (CRCLM), bevacizumab-based neoadjuvant strategies provide increased pathologic response. We aimed at assessing the activity of perioperative capecitabine, oxaliplatin, irinotecan, and bevacizumab (COI-B regimen) in patients with potentially resectable CRCLM, and investigating biomarkers for early prediction of pathologic response.

Assessing the utility of topographic variables in predicting structural complexity of tree stands in a reforested urban landscape

The transformation of natural landscapes into impervious built-up surfaces through urbanization is known to significantly interfere with the ecological integrity of urban landscapes and accelerate climate change and associated impacts. Although urban reforestation is widely recognised as an ideal mitigation practice against these impacts, it often has to compete with other lucrative land uses within an urban area. The often limited urban space provided for reforestation therefore necessitates the optimization of the ecological benefits, which demands spatially explicit information. The recent proliferation of tree stands structural complexity (SSC) and topographic data offer great potential for determining the ecological performance of reforested areas across an urban landscape. This study explores the potential of using topographic datasets to predict SSC in a reforested urban landscape and ranks the value of these topographic variables in determining SSC. Tree structural data from a reforested urban area was collected and fed into a tree stand structural complexity index, which was used to indicate ecological performance. Topographic variables (Topographic Wetness Index, slope, Area Solar Radiation and elevation)- were derived from a Digital Elevation Model (DEM) and used to predict SSC using the Partial Least Squares (PLS) regression technique. Results show that SSC varied significantly between the topographic variables. Results also show that the topographic variables could be used to reliably predict SSC. As expected, the Topographic Wetness Index and slope were the most important topographic determinants of SSC while elevation was the least valuable. These results provide valuable spatially explicit information about the ecological performance of the reforested areas within an urban landscape. Specifically, the study demonstrates the value of topographic data as aids to urban reforestation planning.     

我国丘陵山区农机化水平影响因素及区划研究*——基于全国丘陵山区238个县（市）的调研数据

[目的]通过对全国丘陵山区县(市)与农机化有关的社会、经济和自然条件等因素进行调研所获取的238个有效样本进行分析,研究影响我国丘陵山区农机化水平的因素及其贡献,进而对我国丘陵山区进行区域划分。[方法]运用线性回归法对影响丘陵山区农机化水平的影响因素进行分析,进而对农机化水平产生显著影响的因素进行聚类分析。[结果]国内生产总值、农业劳动力数量对农机化水平产生极显著影响,耕地禀赋条件、务工工资、耕地规模、农机合作社数量和农机推广人员数量对农机化水平产生显著影响。对我国丘陵山区农机化水平呈正相关关系的因素有国内生产总值、务工工资、耕地规模、农机合作社数量,呈负相关的因素有耕地禀赋条件、农业劳动力数量、农机推广人员数量和农机化水平。[结论]我国可丘陵山区划分为中西、东南部地区,北部地区和东部沿海地区3大类地区。     

土地整治对中国粮食产出稳定性的贡献

研究目的:研究土地整治对粮食产出稳定性的贡献,为制定合理高效的土地整治政策,促进粮食增产稳产提供依据。研究方法:采用H-P滤波法实证分析中国粮食产量的波动性及增长趋势,然后基于C-D生产函数,分别建立趋势产量和波动强度面板回归模型,分析土地整治对粮食产出稳定性的影响。研究结果:(1)粮食作物播种面积、农业机械总动力、农用化肥施用量均对粮食长期趋势产生不同程度促进作用;农业劳动力对主产区粮食长期趋势影响显著为负,对非主产区却有正向影响。(2)土地整治面积和单位面积投资额均降低了全国及主产区粮食产量的波动程度,土地整治规模在全国和主产区的影响系数分别为-1.4162和-2.2215;单位土地整治面积投资额在全国和主产区的影响系数分别为-0.7589和-1.3509。(3)土地整治新增耕地面积对全国和主产区的粮食产量波动强度影响为正,影响系数分别为0.8018和1.3931。可能是通过土地整治新增的耕地质量较低,产出不高,导致了粮食产量波动。土地整治投入在非主产区均表现为不显著。研究结论:应继续推进尤其是主产区的土地整治项目实施,加大土地整治投资强度,建立长期稳定的投入机制,合理使用整治资金,注重提高新增耕地质量和综合生产能力,同时将土地整治投入和管理机制与农业生产系统运行机制、自然因素等有效结合,并制定差别化区域政策,以保障粮食增产稳产和区域协调发展。     

重庆地区3～12岁儿童肺通气功能预计方程式的初步建立

目的　建立学龄前期及小学阶段学龄期儿童的肺通气功能参数预计方程式。方法　采用德国JAEGER公司MasterScreen Pead肺功能仪，于2017年4月至2018年9月对重庆地区主城两所幼儿园及小学的458名3～12岁儿童进行肺通气功能测定。采用SAS9.4统计软件包，通过单因素线性回归模型分析各已知及潜在的影响因素与各肺功能参数的相关性，以各肺功能指标实测值为因变量，以性别、年龄、身高、体重为自变量，通过多元逐步回归建立线性回归方程。将构建的方程式与文献中相应年龄段的肺功能预计方程式进行比较，采用相对预测误差平均值评价各公式的适用性。结果　对于学龄前期儿童，肺功能各指标［剩余25%肺活量时的用力呼气流量（MEF25）除外］均与月龄、身高、体重相关，性别与用力肺活量（FVC）、第0.5秒用力呼气容积（FEV0.5）、第1秒用力呼气容积（FEV1）、呼气峰流速（PEF）、MEF75、MEF50和最大通气量（MVV）相关。对于学龄期儿童，年龄、身高、体重与除呼气中段流速（MMEF）外的各肺功能指标均有显著相关性，性别与FVC、FEV1、FEV0.5/FVC、MEF50、MVV显著相关。预计公式模型比较后显示，该次构建的模型对该研究群体有较好的适用性。结论　年龄、身高和体重为影响学龄前期和学龄期儿童肺通气功能参数的主要变量，性别对学龄前期儿童肺功能参数的影响多于学龄期儿童，应根据不同年龄段建立各项肺通气功能指标的预计公式。该模型的构建可为3～12岁儿童肺通气功能相关参数的预测提供帮助。     

A Unified Analysis of Structured Sonar-Terrain Data Using Bayesian Functional Mixed Models

Sonar emits pulses of sound and uses the reflected echoes to gain information about target objects. It offers a low cost, complementary sensing modality for small robotic platforms. Although existing analytical approaches often assume independence across echoes, real sonar data can have more complicated structures due to device setup or experimental design. In this article, we consider sonar echo data collected from multiple terrain substrates with a dual-channel sonar head. Our goals are to identify the differential sonar responses to terrains and study the effectiveness of this dual-channel design in discriminating targets. We describe a unified analytical framework that achieves these goals rigorously, simultaneously, and automatically. The analysis was done by treating the echo envelope signals as functional responses and the terrain/channel information as covariates in a functional regression setting. We adopt functional mixed models that facilitate the estimation of terrain and channel effects while capturing the complex hierarchical structure in data. This unified analytical framework incorporates both Gaussian models and robust models. We fit the models using a full Bayesian approach, which enables us to perform multiple inferential tasks under the same modeling framework, including selecting models, estimating the effects of interest, identifying significant local regions, discriminating terrain types, and describing the discriminatory power of local regions. Our analysis of the sonar-terrain data identifies time regions that reflect differential sonar responses to terrains. The discriminant analysis suggests that a multi- or dual-channel design achieves target identification performance comparable with or better than a single-channel design. Supplementary materials for this article are available online.     

Modeling and surface texturing on surface roughness in machining LaPO4–Y2O3 composite

In this work, lanthanum phosphate with a 20% yttria (LaPO₄/Y₂O₃) composite prepared by an Aqueous Sol–Gel process is machined using an Abrasive Water Jet Machine (AWJM). The machinability of this composite is studied by varying the input parameters namely Jet Pressure (JP), Stand-Off Distance (SOD), and Traverse Speed (TS) on Surface finish. Garnet of 80 mesh size is used as an abrasive with a flow rate of 85?g/min. The microstructural characterization study reveals the presence of new element YPO₄. This element enhances the machinability and reduced porosity in the composite. Microscopy examinations on the machined surface reveals that partial overlapping at low JP, poor surface finish at high JP and SOD, forged deficiency at maximum SOD and TS. The minimum levels of all input parameters are influenced to obtain acceptable Ra. Atomic Force Microscopy (AFM) on the kerf surface shows micro wear track and peaks. The Multiple Regression Analysis (MRA) is developed for Ra to check the adequacy. From the Analysis of Variance (ANOVA), SOD has a significant effect on Ra with a contribution of 53%. The influence of JP and TS on Ra is found to be 31% and 15%, respectively.     

一种自适应步长的复合梯度加速优化算法

自适应步长加速(Adam)类算法由于其计算效率高、兼容性好的特点，成为近期相关领域的研究热点.针对Adam收敛速度慢的问题，本文基于当前梯度、预测梯度以及历史动量梯度，提出一种新型Adam类一阶优化算法——复合梯度下降法(C-Adam)，并对其收敛性进行了理论证明.与其他加速算法的区别之处在于，C-Adam将预测梯度与历史动量区别开，通过一次真实的梯度更新找到下一次迭代更精准的搜索方向.利用两组常用测试数据集及45钢静拉伸破坏实验的实验数据对所提算法进行验证，实验结果表明C-Adam与其他流行算法相比较具有更快的收敛速度及更小的训练损失.     

大尺寸工程模型试验中的相似材料配比试验研究

大型物理模型试验是研究复杂工程问题的重要方法，如何快速、准确地确定相似材料配比是试验中至关重要的一环.为降低试验成本、简化试验步骤、充分调用原料性能，采用河砂、水泥和石膏这三种最普通的原料，以骨胶比(河砂与水泥石膏的质量比)和水膏比(水泥与石膏的质量比)为变量，进行了45组对比试验，对相似材料的物理及动、静力学参数进行了研究.获得了以河砂、水泥和石膏为原料配制的相似材料各物理量的变化区间；探讨了骨胶比和水膏比对相似材料各物理量的控制作用，并对比了其敏感性；基于多元线性回归分析建立了各因素与物理量间的定量关系，得到的拟合公式能较好地描述相似材料的性质.