贺兰山岩画保护区泥石流沟防治规划研究

贺兰山贺兰沟为一典型的泥石流沟,中华数千年的文化艺术瑰宝贺兰山岩画保护区即位于贺兰沟沟口及洪积扇上,经常遭受泥石流的冲积、毁坏和磨损.针对贺兰沟的环境背景条件,在分析泥石流沟特征性状的基础上,提出了因害设防与分区治理相结合、工程措施与生物措施相结合、避灾减灾与应急系统相结合等一系列综合治理规划方案,以期有效解决泥石流对贺兰山岩画和古村落遗址的威胁.     

高温诱导银白杨花粉染色体加倍研究

以银白杨为试验材料,在掌握小孢子母细胞减数分裂规律的基础上采用高温处理诱导花粉染色体加倍,对不同处理温度和处理持续时间在不同减数分裂时期的诱导效果进行了研究。结果表明：温室水培条件下,银白杨完成小孢子母细胞减数分裂大约需3~4d,不同时期和花药颜色变化有相关性;高温诱导银白杨2n花粉的最佳时期是中期Ⅰ,处理条件为36℃持续4h,最高2n花粉百分率39.6%,平均2n花粉百分率32.75%。高温处理后导致银白杨散粉延迟,相对于同一环境条件下的正常花芽散粉晚大约2~3d, 且花粉量很少。     

基于迁移学习与YOLOv8n的田间油茶果分类识别

为降低视觉引导式油茶果采摘机器人采摘被遮挡油茶果时造成的果树和抓取装置损伤,该研究提出了一种基于迁移学习和YOLOv8n算法的油茶果分类识别方法,将油茶果分成无遮挡和遮挡两类。首先,采用COCO128目标检测数据集作为源域,苹果数据集为辅助域的迁移学习方法训练模型。其次,将学习方法、训练数据量、学习率和训练轮数这4种因素组合,共进行了52组YOLOv8n检测性能的消融试验。最后,将YOLOv8n模型与YOLOv3-tiny、YOLOv5n和YOLOv7-tiny等模型进行比较。试验结果表明,随机权重初始化方式受训练数据量和学习率影响较大,学习率为0.01时模型检测效果最好;而迁移学习方法仅用随机权重初始化1/2的数据量即可达到与其相当的平均精度均值;迁移学习方式下,YOLOv8n模型的平均精度均值最高达到92.7%,比随机权重初始化方式提升1.4个百分点。与YOLOv3-tiny、YOLOv5n和YOLOv7-tiny等模型相比,YOLOv8n模型的平均精度均值分别提高24.0、1.7和0.4个百分点,研究结果可为YOLOv8n模型训练参数优化和油茶果分类识别提供参考。     

西藏林芝觉木沟报春花属种质资源及观赏特性

通过调查发现了西藏林芝觉木沟的报春花属植物共6种,分属5个组,编制了分种检索表,并对每种报春花的生物特性和生境类型进行了阐述和归纳,根据各报春花的观赏特性作出了应用推荐。     

毕棚沟风景区红叶彩林景观稳定性分析

以森林资源规划设计调查数据为数据源,定量分析毕棚沟风景区红叶彩林景观格局并运用能更加综合便捷地描述景观稳定性的主成分分析法构建研究区森林景观稳定性评价模型。研究表明:(1)风景区内主要红叶彩林景观类型有鲜卑花林、杜鹃林、四川落叶松林、高山柳林及忍冬林景观。(2)景观稳定性指标中最大斑块指数、斑块所占景观面积比例及斑块内聚力指数对研究区彩林景观类型稳定性影响程度较大。(3)鲜卑花林、杜鹃林、四川落叶松林及忍冬林的景观稳定性较高,花楸林、沙棘林、桦木林及杨树林的景观稳定性低。低稳定性景观类型宜采取改造低价值林分、抚育彩林、构建生态廊道等措施。研究为风景区森林旅游的可持续发展规划提供参考。     

Use of soil chronosequences for testing the existence of high-water-level lakes in the McMurdo Dry Valleys, Antarctica

In this study we utilize field observations and data collected from 190 pedons from Wright and Taylor Valleys to search for evidence of high-water-level lakes proposed to have existed during the Last Glacial Maximum and early Holocene (2.7–25.7 ka) in the McMurdo Dry Valleys. We hypothesize that soils above the uppermost paleo-lake level should be more strongly developed and contain more salts than soils below. During detailed mapping of soils in the Dry Valleys, we found no evidence of former lake sediments nor did we find high-level strandlines except for strandlines on the north valley wall ca. 50 m above Lake Vanda, ice-shove features, or paleo-shore features. However, there may have been minor expansions of major lakes in the McMurdo Dry Valleys. In central Taylor and Wright Valleys, soils on equivalent-aged drifts above and below the conjectured upper limits of Glacial Lakes Washburn (336 m) and Wright (550 m), respectively, are all well developed with no appreciable differences in their properties. Moreover, there were no significant differences in the slopes of regression equations relating soil property to age of the parent materials above and below the high-water lake levels.     

Effect of quinoa flour on gluten-free bread batter rheology and bread quality

A new gluten-free bread formulations composed of quinoa, buckwheat, rice flour and potato starch were developed in the present study. Rheological characteristics of the bread batter with increasing amount of quinoa were determined; storage (G′) and loss modulus (G″) values were also measured for investigation of viscoelastic properties. To evaluate the quality of breads; technological and physical (bake loss %, specific volume, texture, microstructure, color), chemical (protein, moisture, ash) and sensory properties were determined. All batter formulations independent of the quinoa amount exhibited pseudoplastic behavior, and G′ values were found to be higher than G″ values in expressing the solid like characteristics of the batter. Amount of quinoa flour addition did not present significant difference on bake loss%, specific volume and protein content (p>0.05); however, 25% quinoa flour bread displayed better results with its higher sensory scores and softer texture. Quinoa and buckwheat flour mixture therefore will be a good alternative for conventional gluten-free bread formulations.     

评定菜籽粕的肉鸭净能的研究

本试验旨在实测菜籽粕的肉鸭净能(NE),并通过相关、回归分析建立菜籽粕NE与其常规组分之间的回归模型。试验采用析因法将菜籽粕的NE剖分为其提供给肉鸭的维持净能(NEm)和沉积净能(NEp),NEm用肉鸭禁食产热(FHP)来估计,NEp用比较屠宰法测定。选用760只7日龄、平均体重为(130.48±3.01)g的樱桃谷肉鸭进行试验:首先选择100只肉鸭进行NEm评定试验,设自由采食、限饲15%、限饲25%、限饲35%和限饲45%共5个处理,建立产热(HP)和食入代谢能(MEI)的回归关系,外推到MEI为0时求得FHP;然后选择640只鸭进行NEp评定试验,试验前屠宰20只肉鸭测定初始体能量作为起始对照,设基础饲粮组和菜籽粕替代基础饲粮组31个处理,所有处理均设5个重复,每个重复4只肉鸭,15日龄时将肉鸭全部屠宰测定体能量;最后将菜籽粕NE与其常规组分进行相关、回归分析并建立预测模型。结果表明:1)樱桃谷肉鸭的NEm为0.557 MJ/(kg W0.75·d)。2)31种不同菜籽粕的NE有较大差异,经套算法得到菜籽粕的NE为4.18~6.05 MJ/kg DM,NE/表观代谢能(AME)为0.56±0.06。3)菜籽粕NE与其常规组分高度相关,多元线性逐步回归建立的回归模型如下:NE=0.416 AME+0.041 CP-0.020 NDF+0.110 CF-1.093(R2=0.901,RSD=0.06,P0.01),式中:CP为粗蛋白质,NDF为中性洗涤纤维,CF为粗纤维。由此可见,不同来源的菜籽粕的常规组分和肉鸭NE有较大差异,菜籽粕NE与其常规组分高度相关,并具有回归关系。     

基于MODIS数据的伊犁河谷植被指数变化及其对气候的响应

利用2006-2014年主要生长季(5-9月)的MODIS遥感数据,分析了2006-2014年的年平均NDVI和生长季月NDVI变化规律。同时,收集整理同期伊犁河谷地区的气温与降水资料,并对NDVI与当月、2个月滑动、3个月滑动和5个月滑动的平均气温、降水值进行了相关性分析。结果表明,NDVI与气温、降水都存在一定的相关性,NDVI受当月平均气温的影响最大;NDVI与当月降水和滑动平均降水的相关性都很好,但3个月滑动平均降水对NDVI的影响最大,并且通过了0.01的极显著性检验。