对翼龙的几点新解释

在概述翼龙研究状况基础上根据所掌握资料提出：①翼龙发达的胸骨和肩带说明不但能滑翔而且能进行相当强度的动力飞行。②翼龙身覆皮毛显示其具有温血生理特征，其习性在某种程度上可能与鸟类相似，如筑巢、产卵、孵卵及哺雏等。③一些类似水禽的翼龙在足趾间可能长有划水用的蹼。     

Earliest zygodactyl bird feet: evidence from Early Cretaceous roadrunner-like tracks

Fossil footprints are important in understanding Cretaceous avian diversity because they constitute evidence of paleodiversity and paleoecology that is not always apparent from skeletal remains. Early Cretaceous bird tracks have demonstrated the existence of wading birds in East Asia, but some pedal morphotypes, such as zygodactyly, common in modern and earlier Cenozoic birds (Neornithes) were unknown in the Cretaceous. We, herein, discuss the implications of a recently reported, Early Cretaceous (120–110 million years old) trackway of a large, zygodactyl bird from China that predates skeletal evidence of this foot morphology by at least 50 million years and includes the only known fossil zygodactyl footprints. The tracks demonstrate the existence of a Cretaceous bird not currently represented in the body fossil record that occupied a roadrunner (Geococcyx)-like niche, indicating a previously unknown degree of Cretaceous avian morphological and behavioral diversity that presaged later Cenozoic patterns. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

金沙江一期工程蓄水前长江上游产漂流性卵鱼类产卵场现状

2010~2012年每年5~7月在长江上游江津江段开展鱼类产卵场调查。结果表明长江上游现有产漂流性卵鱼类21种,其中特有鱼类6种,分别为长薄鳅(Leptobotia elongata)、红唇薄鳅(Leptobotia rubrilabris)、中华金沙鳅(Jinshaia sinensis)、长鳍吻鮈(Rhinogobio ventralis)、圆筒吻鮈(Rhinogobio cylindricus)和异鳔鳅鮀(Gobiobotia boulengeri)。产漂流性卵鱼类的产卵量分别为32.42×10⁸粒、46.72×10⁸粒和39.71×10⁸粒,其中四大家鱼产卵量分别为3.21×10⁸粒、4.52×10⁸粒和2.69×10⁸粒,铜鱼产卵量分别为1.45×10⁸粒、3.33×10⁸粒和3.87×10⁸粒,长薄鳅产卵量分别为0.29×10⁸粒、0.99×10⁸粒和0.58×10⁸粒。产漂流性卵鱼类产卵高峰出现在5月底~7月初,产卵量日变化与流量和水温日变化显著相关,调查期间日均水位上涨率大于0.24 m/d产卵高峰最为集中。经推算,长江上游榕山镇、合江县和弥沱镇三江段为产漂流性卵鱼类的主要产卵场。金沙江一期工程蓄水后可能会对产漂流卵鱼类的繁殖产生影响。     

雅鲁藏布江上游夏季水化学特征及来源解析

为探究雅鲁藏布江上游干支流的无机水化学特征,于2020年8月在雅鲁藏布江上游河源和河流段采集干支流水样,分析了水体主要离子的化学组成和空间变化规律,并对离子来源进行了解析.结果表明,雅鲁藏布江上游干支流水体中的阴离子以HCO3、SO42为主,分别占阴离子总量的71.11％、23.16％;优势阳离子为Ca2+、Na+,分...     

珠江源区小黄泥河流域地表水水化学组成特征及控制因素

为研究小黄泥河流域地表水水化学组成特征及离子来源,服务小黄泥河流域水资源管理,系统采集了小黄泥河干流及支流河水和矿坑水样品,综合利用Piper三线图、Gibbs图解、离子比例系数和数理统计等方法,分析了小黄泥河河水的水化学组成、空间分布特征和主要控制因素,并评估了不同来源对溶质的贡献率.结果表明,小黄泥河流域河水pH值...     

脉冲通风法治理“U”型工作面上隅角瓦斯积聚的理论及技术探讨

针对生产现场出现的“U”型采煤工作面上隅角瓦斯积聚问题 ,科学地分析了其形成的原因及目前解决上隅角瓦斯积聚的常用方法 ,提出了旋转脉冲法解决此问题的新途径 ,并进行了详细的理论分析。通过现场实验 ,验证了用旋转脉冲法解决上隅角瓦斯积聚是有效的、可行的。     

PUBLIC EXPENDITURE PROGRAMS IN APPALACHIA AND THEIR IMPACT ON REGIONAL EMPLOYMENT1

ABSTRACT: The reduction of regional unemployment requires a sufficient demand for regional labor and the demand pattern must parallel that of supply. Due to the interdependency of Appalachian economy with the rest of the Nation, the leakage of the final demand imposed on a subregion of Appalachia is substantial. The more capital intensive the investment the higher the leakage which will lead to less demand for labor in Appalachia. While water resource projects are generally longterm projects which aim at structural changes in a regional economy, consumption expenditures induced by welfare payments or public employment programs are basically temporary measures for the rescue of unemployment. Average consumption and private investment programs may impose on Appalachia a larger material demand but the demand for the total regional labor, off-site and on-site combined, is estimated to be less than that from water resource investments. The public expenditure program for combating regional unemployment must be discretionary based on its purpose and its potential to generate optimum demand for labor which will be created by the pattern of regional resource distribution and interindustrial and interregional interactions. An interregional I/O model is best suited for analysis of this type.     

ESTIMATION OF WATER TEMPERATURE EXCEEDANCE PROBABILITIES USING THERMO-HYDRODYNAMIC MODELING1

ABSTRACT: A continuous simulation approach is proposed for estimating water temperature exceedance probabilities using thermo-hydrodynamic modeling. The approach uses (1) a deterministic unsteady flow and heat transport model, (2) continuous hydrological and meteorological data for a long historical period, and (3) synthetic records of tributary water temperatures and other model inputs. Representative historical records of streamflow, air temperatures, and other hydrometeorological variables are obtained from nearby gages. Stochastic modeling methods are used to construct synthetic records for other model inputs, including inflow water temperatures. An application of this deterministic-stochastic approach is presented for a complex waterway in northeastern Illinois with heat discharges from several power plants and wastewater treatment plants. Statistical results from the continuous simulations are compared to results obtained from traditional event simulations. The application illustrates the information that engineers and biologists can obtain for (1) evaluating compliance with water temperature standards, and (2) assessing the effect of water temperatures on aquatic habitat.     

长江上游干旱灾害分析及防灾减灾措施

分析了长江上游历年干旱灾害发生的频率、危害程度和演变趋势。长江上游受太平洋高压和地形的影响，造成四川盆地西部和黔西北的春旱、盆东伏旱，盆中黔东北旱伏连旱，以及金沙江与大渡河的干热旱型。干旱的危害程度既受天气背景的影响，又与人类活动方式密切相关，异常的天气过程只有在人口密集，生产发达的地区才能形成显著的灾害，从近三百年的水文气象条件看，洪水发生略有加强，而干旱则略有减弱。但是近代工农业高速发展，人口