环志朱鹮生命表及繁殖情况的分析研究

在 198 7～ 1997年的 11年里 ,采用鸟类环志的方法研究了野生朱的存活和死亡状况 ,编制了动态生命表 ;并对其繁殖地、繁殖情况及年龄组的存活数量等做了分析、发现洋县野生朱种群中 ,当年幼鸟死亡率比较高 .增加种群数量的关键是保护当年的幼鸟 .     

应用一元二次方程求增长率

关于增长率的有关知识,在小学里我们就学过.例如.某钢铁厂第一年的产量是100万吨,第二年的产量是120万吨,第二年比第一年增加的百分数.(120-100)/100=0.2=20%即为增长率.如果每年比上一年增加的百分数相同,就称它为年平均增长率.那么上例中,如果年平均增长率为20%,第三年(即经过两年)的产量是100(1+20%)(1+20%)=100(1+20%)~2=144(万吨).一般来说,设原来的年产量为 a,年平均增长率为 x,那么经过一年的年产量等于 a(1+x),经过两年的年产量等于 a(1+x)~2,经过三年的年产量等于 a(1+x)~3,经过 n 年的年产量等于 a(1+x)~n.对于增长率的问题,都可应用上述关系式.例1 苏州服装厂1989年生产某种服装100万件,由于加快了改革开放的步伐,1991年生产这种服装625万件,求这两年平均每年增长的百分率.(1992年苏州市中考试题)     

贵州独山地区金翅雀的生态繁殖行为观察

对独山地区金翅雀的生态繁殖进行观察,并用Logistic方程对雏鸟外部器官的生长数据进行拟合.结果表明:繁殖期为3～7月,营巢期5～7d,巢的结构为三层,窝卵数(4.2±0.16)枚(n=9),孵化期为(12±0.45)d(n=9).孵化率为84％ (21/25) (n =5),雏鸟留巢期(13±0.45)d,雏鸟离巢率为90.46％.测量雏鸟的体重、体长、嘴峰长、第5枚初级飞羽、尾长、跗跖.雏鸟的外部器官的生长发育符合雀形目外部器官发育规律.     

十大问题

中等职教规模发展缓慢 中等职业教育扩招速度远低于普通高中.2000年到2003年,全国初中毕业生数由1607.1万人增至1995.6万人,增加了388.5万人,从生源上为高中阶段教育的大规模扩招提供了有利的条件.但中等职业学校的扩招速度远远跟不上普通高中,从2000到2003年,普通高中招生数从472.7万增加到752.1万,增长率为59.1%.而2001年全国中等职业学校招生数为353万人,反而比2000年减少4.6万人;此后二年虽然有回升,达到2003年的515万人,但从2000年到2003年中等职业学校招生增长率仅为39.1%,比普通高中低了近20个百分点(见表2).     

种群增长率与增长速率的区别

种群增长率与种群增长速率虽一字之差,但内涵完全不同。增长率是指：单位数量的个体在单位时间内新增加的个体数,其计算公式为：（这一次总数-上一次总数）,上一次总数＊100％=增长率。如某种群现有数量为a,一年后,该种群数为b,那么该种群在当年的增长率为（b-a）／a。增长速率是指单位时间内增长的数量。其计算公式为：（这一次总数-上一次总数）／时间=增长速率。同样某种群现有数量为a,一年后,该种群数为b,其种群增长速率为：（b—a）／1年。即增长率=出生率一死亡率。故增长率不能等同于增长速率。     

云南省国民生产总值增长率的初步分析

在对云南省1952年至2005年国民生产总值增长率进行了初步分析研究的基础上,揭示了云南省国民生产总值增长率的变化情况,周期波动呈现出峰位降低、谷位上升、波幅缩小的态势,54年中,云南与全国经济增长速度相比呈现出“28高、24低、2平”的特点,十个五年计划期间,云南国民经济增长呈现出“七快、两慢、一下降”的特点。     

既有复线增建涵洞工字钢扣轨施工技术

株六复线贵阳枢纽C标增建二线线下工程,在既有路基处增建新建涵洞(采用明挖施工),设计要求采用P43钢轨加固线路,行车速度不能大于15 km,但实际上路基处于曲线半径R=500及坡比是i=1.2%上坡地段,行车速度不低于45 km,故采用P36字钢取代P43钢轨做纵梁,进行扣轨加固施工.     

人口增长转变为现代型的判断标准

在政策和社会发展的双重作用下,从20世纪70年代后期开始,中国人口增长率不断下降,人口规模的净增量也逐年缩小。20世纪70年代初,每年人口出生数高达2700万,人口净增量每年高达2000万以上,如今,每年出生人数降到1600万左右,人口年净增量已经降到800万左右。人口再生产类型完成了从高出生率、低死亡率、高人口增长率的传统人口再生产类型,向低出生率、低死亡率、     

地理科试题精选

一、选择题(一)单项选择题图1所示的是经纬网,据图回答1～3题。1.下列各线段比例尺的比较,正确的是()A.ab﹥cd﹥ac=bdB.cd﹥ab﹤bd﹤acC.ac﹥bd﹥ab﹥cdD.bd=ac﹥ab=cd2.当ac经线为晨线时()A.a处的区时为6时B.北京时间为7时20分C.c处的正午太阳高度达一年中最大值D.b处昼长夜短3.当d处为9日6时,这时处于9日范围的地区占全球面积的比例是()A.一半B.大于一半C.小于一半D.无法确定2004年12月当地时间26日上午,苏门答腊岛附近海域(图2中A处)发生40年来世界最强烈地震,并引发海啸,东南亚和南亚数个受波及国家死亡失踪人数已逼近30万人,远在…     

零点存在定理与幂、指函数的比较

2004年教育部推出的高中新课程的数学配套教材必修1中引入了零点存在定理:连续函数y=f(x)在[a,b]的端点处的函数值符号相反,则y=f(x)在(a,b)内至少有一个零点存在.该定理简单易懂,并给出了判定方程是否有解及求近似解的依据.此定理还可进一步推广:交点存在定理:两连续函数y=f(x)与y=g(x)在[a,b]的端点处的函数值大小相反,则y=f(x)与y=g(x)在(a,b)内至少存在一个交点.例1张三和李四两同学很喜欢数学,平时总喜欢把身边的事变成数学问题互相提问.暑假时同登泰山,早上6时从山下出发边走边玩至12时到达南天门,第二天早上6时从南天门出发估计至12…     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.