On the behaviour of the residence time at the bottom of the mixed layer

To understand why the findings of Deleersnijder et al. [(2006), Environ Fluid Mech 6: 25–42]—the residence time in the mixed layer in not necessarily zero at the pycnocline—are consistent with those of Delhez and Deleersnijder [(2006), Ocean Dyn 56:139–150]—the residence time in a control domain vanishes at the open boundaries of this control domain—, it is necessary to consider a control domain that includes part of the pycnocline, in which the eddy diffusivity is assumed to be zero. Then, depending on the behaviour of the eddy diffusivity near the bottom of the mixed layer, the residence time may be seen to exhibit a discontinuity at the interface between the mixed layer and the pycnocline. If such a discontinuity exists, the residence time is non-zero in the former and zero in the latter. This is illustrated by analytical solutions obtained under the assumption that the eddy diffusivity is constant in the mixed layer.     

知识型员工的特点、激励及管理对策研究

知识经济时代，企业最宝贵的财富是知识型员工。知识型员工是生产力的代表。知识型员工的工作效率决定了企业的竞争能力．因此。如何激励知识型员工成为企业探讨的一个重要问题．本文从知识型员工的特点入手。按有关知识管理专家提出的激励因素，从四个方面阐述了对知识型员工的激励策略。并提出了对知识型员工的管理对策．     

豪猪消化系统的解剖研究

为了了解豪猪的消化生理,为豪猪的人工饲养技术研究提供基础依据,以达到高效饲养豪猪的目的,笔者对豪猪的消化器官进行了系统解剖研究.结果表明:豪猪的胃为单室胃.盲肠很发达,这与其能够消化植物纤维有关.豪猪肝脏很发达,其重量为402 g,是其体重的4.59%,肝脏分叶多而明显.     

Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e. peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e. expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where economic growth, which requires more oil, would require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.     

Splitting the tail of the displacement kernel shows the unimportance of kurtosis

Animals disperse in space through different movement behaviors, resulting in different displacement distances. This is often described with a displacement kernel where the long-distance dispersers are within the tail of the kernel. A displacement with a large proportion of long-distance dispersers may have impact on different aspects of spatial ecology such as invasion speed, population persistence, and distribution. It is, however, unclear whether the kurtosis of the kernel plays a major role since a fatter tail also influences the variance of the kernel. We modeled displacement in landscapes with different amounts and configurations of habitats and handled kurtosis and variance separately to study how these affected population distribution and transition time. We conclude that kurtosis is not important for any of these aspects of spatial ecology. The variance of the kernel, on the other hand, was of great importance to both population distribution and transition time. We argue that separating variance and kurtosis can cast new light on the way in which long-distance dispersers are important in ecological processes. Consequences for empirical studies are discussed.     

Observations on the function of the glands of the foot of the pediveliger of Ostrea edulis during settlement

The use during settlement of secretions of the 9 different types of gland in the foot of the pediveliger of Ostrea edulis L. was examined experimentally. During settlement, there is a progressive decrease in the crawling speed of the larva and a strengthening of its bond with the substratum. Both changes are related to (a) a change from ciliary to muscular pedal locomotion; (b) the increasing acidity and viscosity of the mucoid secretions used; (c) the secretion of a byssus thread by the glands of the byssus duet; (d) changes in the form and composition of this byssus. At the termination of settlement, the entire contents of 2 types of gland are discharged. Their secretions give rise to the cement which permanently fixes the larva to the substratum. The 9 types of gland are utilised sequentially in a manner closely related to the 6 phases recognised in settlement behaviour.     

Conservation and the Lure of the Garden

Abstract:  Among the conservation voices today who seek a sensible "middle ground" in remedying land-use problems are those who propose a tend-the-garden ethic in which humans would merely need to view the earth as a garden and labor to make it productive and beautiful in order to solve conservation challenges. This line of reasoning is exemplified by Michael Pollan's highly praised book, Second Nature , which supports conservation values but harshly criticizes contemporary environmental efforts, including the work of such organizations as The Nature Conservancy. Pollan's portrayal of the gardener as model conservationist is usefully compared with an important essay by Aldo Leopold from a half-century ago, "The Farmer as a Conservationist," which similarly uses a model land tender as exemplar of where conservation needs to head. Comparing the two writings reveals profound flaws in the contemporary tend-the-garden line of thought. In doing so, it usefully reveals to scientists why their efforts are so often misunderstood and resisted. The popularity of tend-the-garden reasoning illustrates how successful the environmental backlash has been in misportraying the motives and aims of serious conservationists, particularly those who seek to protect wildlife and natural habitat. In doing so, it highlights the need for conservationists to take their own ideas more seriously and to do a far better job of presenting those ideas, in coherent form, to broad audiences.     

高产玉米因土高效施肥技术研究

通过田间试验,研究广东省粤东河源灯塔盆地的粉砂坭地和粤北阳山县石灰岩山区的黄泥地氮、磷、钾养分的供应特性;高产玉米不同生育期吸收氮、磷、钾的规律,以及在不同土壤上氮、磷、钾肥的不同配比对玉米产量和经济效益的影响。根据试验结果进行统计,提出了高产玉米因土高效施肥技术方法。     

Assessing the relation between the distribution of salt-marsh communities and the sediment budget of the North Norfolk coast

Very high resolution imagery from an airborne multi-spectrål scanner has been used to estimate the distribution of different salt-marsh communities along a 30-km stretch of the North Norfolk coast. Field observations have been used to develop a mathematical relationship between the vegetation, physical environment and sediment accumulation. This relationship has been used to produce provisional sediment accretion maps for the north Norfolk coast.     

Mining of the forest and the time path of the price of timber

The paper analyzes the effect of transportation (site specific) costs and the effect of mining (depletion) of the forest on the time path of the price and of the net price of timber in two forestry models. The models differ in that one has zero costs and the other has positive costs. The analyses yield the standard mining theory results for certain cases. They also yield extentions of these results for cases with growth of the harvested trees and/or regeneration on the harvested land. The paper concludes, as one would expect, that the theory of the mine is useful in analyzing the time path of the price of timber.     

Beliefs about the environment: moving from the egocentric towards the ecocentric perspective

Our behaviour towards the environment depends on our beliefs about the environment. Beliefs, however, are a subject of change, particularly during important life transitions such as the transition to adolescence, because this is a period when an individual develops the ability of complex and abstract reasoning. Understanding this transition is therefore crucial for understanding and predicting the attitudes and courses of action in terms of sustainable development later in life. Due to many methodological constraints, the number of empirical studies examining these issues is very limited; the current study aimed to collect empirical data to explore the origins of our beliefs about the environment-related issues. We devised a picture association test and used it to compare children’s and adolescents’ beliefs about our environment in the context of the means of transportation. A large sample of 2264 participants aged 6–18 years took part in the study. The data supported the claim that children’s beliefs about environment share egocentric properties. The findings represent an important puzzle into the whole picture of children’s thinking and offer us great insight into the origins of beliefs about environment-related questions in adults. Educational implications are addressed.     

浅谈校园网ARP欺骗攻击与防御

ARP欺骗木马病毒是校园网络中经常出现的病毒攻击形式．基于ARP协议的概念和工作原理,并通过分析ARP欺骗的工作原理,提出了几种可行的解决ARP欺骗攻击的实用方法,以达到防范并解决ARP欺骗的目的．参5．     

A historical survey of the appendicularians from the area covered by the IIOE

The present paper shows how our knowledge concerning the appendicularians from the Indian Ocean, the Red Sea and the Persian Gulf has evolved. The different historical steps and their relative importance are discussed, and the contributions, either direct or indirect, of the International Indian Ocean Expedition (IIOE) are emphasized.     

The impact of the Jonglei Canal on the economy of the local people

The idea of saving the water lost in the ‘Sudd’ swamp through evaporation was conceived by Egypt and Sudan for their own interests, but not for those of the Nilotic peoples living in the flood plain. Concern for the local development was only taken into consideration after the 1974 Juba riots, when three people were killed and 200 arrested. The canal has caused displacement of people from their settlements and is blocking the seasonal movement of livestock and wildlife. Conflict may arise over the use of land for grazing or irrigation. The Nilotics are concerned about the possible negative environmental impact, and the loss of their cultural identity. They maintain that Egypt should pay them monetary compensation for the disruption that the canal has caused to their livelihood.

This paper assesses the impact that the Jonglei canal project will have on the economy of the Nilotics; traces the historical development of the project; outlines the social, political and economic organization of the Nilotics; and assesses the impact the project will have on the local population. The paper concludes by casting doubt on the benefits the canal will bring to the Nilotics.     

刍议医院资产管理的现状及其对策

医院的固定资产和流动资产是医院赖以生存和发展的基础,是一项非经营性国有资产．目前公立医院固定资产、流动资产管理现状不容乐观,针对这种状况,首先分析问题形成的原因,然后提出管理的措施或建议,从而使资产管理工作规范化、制度化、科学化,使有限的卫生资源发挥出最大的社会效益和经济效益．参3．