Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assig...Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assigned to free-access feeding of acidified (ACID, n = 31) or non-acidified (NON, n = 31) MR, and weaned at 42 days. ACIDMR was prepared to pH 4.0 - 4.5 using formic acid. Intakes were measured daily and weights weekly. Samples of ACID and NON MR were analyzed for coliform and aerobic bacterial growth. After weaning, calves transitioned to a grain-fed veal diet, weighed every 2 weeks. At slaughter (approximately 6 months of age), lungs were evaluated for gross pathological changes and dressed carcass weights were obtained. Generalized linear mixed models were constructed to examine the effects of MR acidification. Differences by treatment group for pre- and post-weaning morbidity and mortality were tested using Pearson’s χ2 and Fisher’s exact tests. ACID calves consumed less MR than NON (10.6 vs. 11.7 L/d, P = 0.02). Acidification tended to promote earlier onset of starter ration consumption (32.0 vs. 39.5 d, hazard ratio = 1.5, P = 0.07), but did not affect average daily starter ration or water intakes across the pre-weaning period. ACID and NON calves did not differ for BW at weaning, pre- or post-weaning ADG or dressed carcass weight. ACID MR had less coliform (P < 0.001) and aerobic bacterial growth (P < 0.001) than NON MR, but odds of disease treatment and mortality did not differ. ACID calves tended to have lower odds of pulmonary lesions during post-mortem inspection than NON calves (OR = 0.3, P = 0.07). These results indicate that under free-access feeding conditions, acidification limited bacterial growth and MR intake, but there were no long-term impacts of acidification on calf performance or health. In conclusion, acidification to pH 4.0 - 4.5 will significantly reduce bacterial growth in milk fed to calves.展开更多
在面向卫星物联网的免授权随机接入(Grant-free Random Access,GFRA)系统中,受大规模连接和设备随机激活的影响,前导碰撞成为用户接入性能提升的主要制约因素。鉴于此,借助正交与非正交序列在前导检测和冲突抑制方面的各自优势,提出一...在面向卫星物联网的免授权随机接入(Grant-free Random Access,GFRA)系统中,受大规模连接和设备随机激活的影响,前导碰撞成为用户接入性能提升的主要制约因素。鉴于此,借助正交与非正交序列在前导检测和冲突抑制方面的各自优势,提出一种基于混合ZC(Zadoff-Chu)序列的大容量前导设计和检测方法。该方法利用正交ZC序列与其循环移位映射的不同根ZC序列级联来构建前导序列,并采用一种基于假设检验的两阶段干扰消除活跃用户检测算法,以确保大规模接入场景下的高精度用户识别。此外,对所提前导结构进行扩展,将相位旋转因子与多段非正交序列相结合,在不增加峰均比的前提下进一步扩大前导集容量。所提方法较现有复合和正交前导方法具有显著改善的多用户识别性能,在相同活跃用户下,成功检测概率最大提升约30.3%。展开更多
随着工艺制程的不断微缩,动态随机存储器(dynamic random access memory,DRAM)的集成度持续提高,单颗芯片上存储单元的数目呈指数增长,随之带来的是芯片发热严重和泄漏电流增大等问题,为了实时监测内部温度并控制相应的刷新操作,DRAM需...随着工艺制程的不断微缩,动态随机存储器(dynamic random access memory,DRAM)的集成度持续提高,单颗芯片上存储单元的数目呈指数增长,随之带来的是芯片发热严重和泄漏电流增大等问题,为了实时监测内部温度并控制相应的刷新操作,DRAM需要在内部集成温度传感器。文章从DRAM的基本结构、工作原理和实际工作中对内置温度传感器的需求出发,研究不同读出架构的集成式温度传感器的优缺点,考虑到感温精度、感温范围、功耗和成本等因素以及DRAM产品规格说明书中对内置温度传感器的要求,设计出一款基于时域读出架构的免校准低功耗温度传感器。采用19 nm的互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)工艺进行仿真验证,结果表明,免校准的前提下,该温度传感器在0~110℃的感温范围内具有3℃的仿真精度,版图面积为0.189 mm^(2),平均功耗为340.31μW,感温时间为550μs。文章设计的温度传感器满足DRAM对于内置温度传感器的要求,且大大降低了DRAM的生产成本。展开更多
文摘Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assigned to free-access feeding of acidified (ACID, n = 31) or non-acidified (NON, n = 31) MR, and weaned at 42 days. ACIDMR was prepared to pH 4.0 - 4.5 using formic acid. Intakes were measured daily and weights weekly. Samples of ACID and NON MR were analyzed for coliform and aerobic bacterial growth. After weaning, calves transitioned to a grain-fed veal diet, weighed every 2 weeks. At slaughter (approximately 6 months of age), lungs were evaluated for gross pathological changes and dressed carcass weights were obtained. Generalized linear mixed models were constructed to examine the effects of MR acidification. Differences by treatment group for pre- and post-weaning morbidity and mortality were tested using Pearson’s χ2 and Fisher’s exact tests. ACID calves consumed less MR than NON (10.6 vs. 11.7 L/d, P = 0.02). Acidification tended to promote earlier onset of starter ration consumption (32.0 vs. 39.5 d, hazard ratio = 1.5, P = 0.07), but did not affect average daily starter ration or water intakes across the pre-weaning period. ACID and NON calves did not differ for BW at weaning, pre- or post-weaning ADG or dressed carcass weight. ACID MR had less coliform (P < 0.001) and aerobic bacterial growth (P < 0.001) than NON MR, but odds of disease treatment and mortality did not differ. ACID calves tended to have lower odds of pulmonary lesions during post-mortem inspection than NON calves (OR = 0.3, P = 0.07). These results indicate that under free-access feeding conditions, acidification limited bacterial growth and MR intake, but there were no long-term impacts of acidification on calf performance or health. In conclusion, acidification to pH 4.0 - 4.5 will significantly reduce bacterial growth in milk fed to calves.
文摘在面向卫星物联网的免授权随机接入(Grant-free Random Access,GFRA)系统中,受大规模连接和设备随机激活的影响,前导碰撞成为用户接入性能提升的主要制约因素。鉴于此,借助正交与非正交序列在前导检测和冲突抑制方面的各自优势,提出一种基于混合ZC(Zadoff-Chu)序列的大容量前导设计和检测方法。该方法利用正交ZC序列与其循环移位映射的不同根ZC序列级联来构建前导序列,并采用一种基于假设检验的两阶段干扰消除活跃用户检测算法,以确保大规模接入场景下的高精度用户识别。此外,对所提前导结构进行扩展,将相位旋转因子与多段非正交序列相结合,在不增加峰均比的前提下进一步扩大前导集容量。所提方法较现有复合和正交前导方法具有显著改善的多用户识别性能,在相同活跃用户下,成功检测概率最大提升约30.3%。
文摘随着工艺制程的不断微缩,动态随机存储器(dynamic random access memory,DRAM)的集成度持续提高,单颗芯片上存储单元的数目呈指数增长,随之带来的是芯片发热严重和泄漏电流增大等问题,为了实时监测内部温度并控制相应的刷新操作,DRAM需要在内部集成温度传感器。文章从DRAM的基本结构、工作原理和实际工作中对内置温度传感器的需求出发,研究不同读出架构的集成式温度传感器的优缺点,考虑到感温精度、感温范围、功耗和成本等因素以及DRAM产品规格说明书中对内置温度传感器的要求,设计出一款基于时域读出架构的免校准低功耗温度传感器。采用19 nm的互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)工艺进行仿真验证,结果表明,免校准的前提下,该温度传感器在0~110℃的感温范围内具有3℃的仿真精度,版图面积为0.189 mm^(2),平均功耗为340.31μW,感温时间为550μs。文章设计的温度传感器满足DRAM对于内置温度传感器的要求,且大大降低了DRAM的生产成本。
