OFDM系统中自适应比特分配算法分析

对单用户OFDM系统的3种自适应比特加载算法:Hugehes-Hartogs比特功率梯度分配算法、Chow算法和简单分块加载(SBLA)算法进行了仿真,分析比较了3种算法的复杂度和抗噪声性能。仿真结果表明:每种算法各有其优缺点和适用情况,可以根据不同的工程需求选择不同的算法。Hugehes-Hartogs算法能使系统发射总功率达到最低;Chow算法具有较好的抗噪声性能;SBLA算法的性能介于上述2种算法之间,并且具有较低的复杂度。     

从洛杉矶中国城的变迁探讨我国传统建筑文化在海外的影响

回顾华人移民北美和中国城建设的历史，探讨洛杉矶中国城变迁、建筑风格的形成以及中国传统文化的影响。     

Vagotomy Blocks Hypothalamic Hyperphasia in Rats on a Chow Diet and Sucrose Solution, but Not on a Palatable Mixed Diet: Correction.

Reports an error in the original article by A. Sclafani, P. Aravich and M. Landman (Journal of Comparative and Physiological Psychology, 1981, Vol. 95, No. 5, 720-734). Table 3 contains several errors in the mean and standard error values for the second and third groups. The correct table is provided. (The following abstract of this article originally appeared in record 1982-09338-001): Adult female Sprague-Dawley rats were given ventromedial hypothalamic parasagittal knife cuts (VMH treatment) or control surgery (Con treatment), followed 10 days later by subdiaphragmatic vagotomy (Vag treatment) or sham vagotomy (Sham treatment). The hyperphagia and obesity produced by the VMH cuts to Ss on a chow diet was completely blocked by vagotomy (VMH-Vag group). Vag also inhibited the VMH Ss' overconsumption of a 20% sucrose solution during 1-hr/day and 24-hr/day tests, which contrasts with the effects of atropine treatment. However, when offered a selection of palatable foods (cookies, sweet milk, high-fat ration) in addition to chow, VMH-Vag Ss overate and gained considerably more weight than did the Con-Vag or the Con-Sham Ss. Con-Vag Ss, on the other hand, gained less weight than Con-Sham Ss on the palatable diet. Results indicate that intact subdiaphragmatic vagi are not essential for the expression of VMH hyperphagia and finickiness, and they therefore question the role of vagally mediated cephalic responses in the hypothalamic hyperphagia syndrome. On the other hand, results indicate that in brain-intact animals Vag suppresses the development of diet-induced obesity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal Changes in Diet Cause Repeatable and Largely Reversible Shifts in Gut Microbial Communities of Laboratory Mice and Are Observed across Segments of the Entire Intestinal Tract

Dietary changes are known to alter the composition of the gut microbiome. However, it is less understood how repeatable and reversible these changes are and how diet switches affect the microbiota in the various segments of the gastrointestinal tract. Here, a treatment group of conventionally raised laboratory mice is subjected to two periods of western diet (WD) interrupted by a period of standard diet (SD) of the same duration. Beta-diversity analyses show that diet-induced microbiota changes are largely reversible (q = 0.1501; PERMANOVA, weighted-UniFrac comparison of the treatment-SD group to the control-SD group) and repeatable (q = 0.032; PERMANOVA, weighted-UniFrac comparison of both WD treatments). Furthermore, we report that diet switches alter the gut microbiota composition along the length of the intestinal tract in a segment-specific manner, leading to gut segment-specific Firmicutes/Bacteroidota ratios. We identified prevalent and distinct Amplicon Sequencing Variants (ASVs), particularly in genera of the recently described Muribaculaceae, along the gut as well as ASVs that are differentially abundant between segments of treatment and control groups. Overall, this study provides insights into the reversibility of diet-induced microbiota changes and highlights the importance of expanding sampling efforts beyond the collections of fecal samples to characterize diet-dependent and segment-specific microbiome differences.     

Improvement of insulin resistance by Hon-Chi in fructose-rich chow-fed rats

In an attempt to develop new substances for handling insulin resistance, the effect Hon-Chi was examined on insulin resistance induced by fructose-rich chow in rats. Mandarin Hon-Chi is red yeast rice fermented with Monascus pilous and Monascus purpureus. Single oral administration of Hon-Chi for 90 min decreased the plasma glucose in a dose-dependent manner in rats, which had received four-week fructose-rich chow. The insulin action on glucose disposal rate using the glucose–insulin index, and the value of the areas under the curve of glucose and insulin during the intraperitoneal glucose tolerance test were measured. Oral administration (three times daily for three-days) of Hon-Chi into rats, which received four-week fructose-rich chow, reversed the elevated value of glucose-insulin index, indicating Hon-Chi has an ability to improve insulin resistance. The time for the loss of plasma glucose lowering response to tolbutamide in fructose-rich chow-fed rats was markedly delayed by the repeated treatment of Hon-Chi, as compared to the vehicle-treated group. This provided the supportive data that oral administration of Hon-Chi could delay the development of insulin resistance in rats. Increase of insulin sensitivity by Hon-Chi was further identified using the plasma glucose lowering action of exogenous insulin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Oral administration of Hon-Chi at 150 mg/kg three times daily into STZ-diabetic rats caused an increase in the responses to exogenous insulin 15-days later. The obtained results suggest that oral administration of Hon-Chi has the ability to improve insulin sensitivity and delay the development of insulin resistance in rats, which may be used as an adjuvant therapy to patients with insulin resistance.