Centralized Governance and Student Outcomes: Excellence,Equity, and Academic Achievement in the U.S. States

Are states with more centralized approaches to education governance more likely to have higher student achievement and lower achievement gaps between poor and nonpoor students? This article addresses that question by theorizing about the effects of political, administrative, and fiscal centralization on student outcomes. It tests competing hypotheses about the degree to which centralization across these three dimensions is associated with the promotion of academic excellence (higher achievement) and equity (narrower achievement gaps). The results demonstrate the virtue of studying academic performance through the lens of governance and more distal system‐level variables rather than, as has been common in the literature, more narrow policy‐oriented measures. The findings show that strong relationships exist between student outcomes and the degree of political centralization and administrative centralization in a state, yet there are no apparent associations with fiscal centralization. The results also illustrate that governing arrangements are not consistently related to the advancement of excellence and equity. In terms of administrative centralization, specifically, apparent trade‐offs may exist.     

HISTORY,INSTITUTIONS, AND CITIES: A VIEW FROM THE AMERICAS*

ABSTRACT Every nation, formally or informally, defines and establishes the lines of political and fiscal authority among its national, regional, and local governments. Historically, centralized governments tend to restrict the power and autonomy of provincial and local governments. In this paper, we exploit the quasi‐experimental distribution of political institutions in the Americas caused by variation in European colonial experience to examine the impact of institutions on urban and local development, specifically on the degree of urban primacy, the size distribution of cities, the number and density of local government units, and the fragmentation of metropolitan areas. We argue that centralization of political power at the national level, as experienced in many countries in Latin America, contributes to urban primacy and a size distribution of cities favoring large cities. Additionally, even in more politically decentralized countries such as Canada and the U.S., variance in political centralization at the provincial (state) level over local governments led to significant divergences in urban primacy, the distribution of city sizes, as well as the form, number, and density of local governments. While we cannot rule out the importance of other factors, our findings suggest that political centralization affects spatial economic development.     

Modeling fluid flow in a heterogeneous, fault-controlled hydrothermal system

Previous studies have shown that most hydrothermal systems discharging at the land surface are associated with faulting, and that the location, temperature and rate of discharge of these systems are controlled by the geometry and style of the controlling fault(s). Unfortunately, the transport of heat and fluid in fault-controlled hydrothermal systems is difficult to model realistically; although heterogeneity and anisotropy are assumed to place important controls on flow in faults, few data or observations are available to constrain the distribution of hydraulic properties within active faults. Here, analytical and numerical models are combined with geostatistical models of spatially varying hydraulic properties to model the flow of heat and fluid in the Borax Lake fault of south-east Oregon, USA. A geometric mean permeability within the fault of 7 × 10⁻¹⁴ m² with 2× vertical/horizontal anisotropy in correlation length scale is shown to give the closest match to field observations. Furthermore, the simulations demonstrate that continuity of flow paths is an important factor in reproducing the observed behavior. In addition to providing some insight into possible spatial distributions of hydraulic properties at the Borax Lake site, the study highlights one potential avenue for integrating field observations with simulation results in order to gain greater understanding of fluid flow in faults and fault-controlled hydrothermal and petroleum reservoirs.     

The interplay of permeability and fluid properties as a first order control of heat transport, venting temperatures and venting salinities at mid-ocean ridge hydrothermal systems

While the fundamental influence of fluid properties on venting temperatures in mid-ocean ridge (MOR) hydrothermal systems is now well established, the potential interplay of fluid properties with permeability in controlling heat transfer, venting temperatures, and venting salinities has so far received little attention. A series of numerical simulations of fully transient fluid flow in a generic, across-axis model of a MOR with a heat input equivalent to magmatic supply at a spreading rate of 10 cm year⁻¹ shows a strong dependence of venting temperature and salinity on the system's permeability. At high permeability, venting temperatures are low because fluid fluxes are so high that the basal conductive heating cannot warm the large fluid masses rapidly enough. The highest venting temperature around 400°C as well as sub-seafloor fluid phase separation occur when the permeability is just high enough that the fluid flux can still accommodate all heat input for advection, or for lower permeabilities where advection is no longer capable to transfer all incoming magmatic heat. In the latter case, additional mechanisms such as eruptions of basaltic magma may become relevant in balancing heat flow in MOR settings. The results can quantitatively be explained by the 'fluxibility' hypothesis of Jupp & Schultz (Nature, 403 , 2000, 880), which is used to derive diagrams for the relations between basal heat input, permeability and venting temperatures. Its predictive capabilities are tested against additional simulations. Potential implications of this work are that permeability in high-temperature MOR hydrothermal systems may be lower than previously thought and that low-temperature systems at high permeability may be an efficient way of removing heat at MOR.     

Klinkenberg gas slippage measurements as a means for shale pore structure characterization

Established techniques that have been successfully used to characterize pore systems in conventional reservoir rocks lack the resolution and scalability required to adequately characterize the nano‐ to micrometer scale pore systems found in shale and cannot be applied on stressed samples. We have therefore investigated the utility of Klinkenberg gas slippage measurements for shale pore structure characterization. In contrast to other approaches, slippage measurements characterize the effective porosity of core samples and can be applied at stress conditions experienced in the reservoir during production. Slippage measurements on horizontally and vertically oriented samples from the Eagle Ford Shale Formation, Texas, USA, at a range of stress states revealed two orders of magnitude in slippage variation over five orders of magnitude permeability range. Slippage measurements are negatively correlated with permeability and follow similar trends to those found in other studies on higher permeability rocks. The samples had varying degrees of slippage anisotropy, which allowed interpretation of the relative contribution of tortuosity and pore size to permeability anisotropy. Slippage and therefore average effective pore size was found to vary up to one order of magnitude at a given permeability, warranting investigation of the significance this might have on flow properties and ultimately hydrocarbon production from shale.     

Effects of episodic fluid flow on hydrocarbon migration in the Newport‐Inglewood Fault Zone,Southern California

Fault permeability may vary through time due to tectonic deformations, transients in pore pressure and effective stress, and mineralization associated with water‐rock reactions. Time‐varying permeability will affect subsurface fluid migration rates and patterns of petroleum accumulation in densely faulted sedimentary basins such as those associated with the borderland basins of Southern California. This study explores the petroleum fluid dynamics of this migration. As a multiphase flow and petroleum migration case study on the role of faults, computational models for both episodic and continuous hydrocarbon migration are constructed to investigate large‐scale fluid flow and petroleum accumulation along a northern section of the Newport‐Inglewood fault zone in the Los Angeles basin, Southern California. The numerical code solves the governing equations for oil, water, and heat transport in heterogeneous and anisotropic geologic cross sections but neglects flow in the third dimension for practical applications. Our numerical results suggest that fault permeability and fluid pressure fluctuations are crucial factors for distributing hydrocarbon accumulations associated with fault zones, and they also play important roles in controlling the geologic timing for reservoir filling. Episodic flow appears to enhance hydrocarbon accumulation more strongly by enabling stepwise build‐up in oil saturation in adjacent sedimentary formations due to temporally high pore pressure and high permeability caused by periodic fault rupture. Under assumptions that fault permeability fluctuate within the range of 1–1000 millidarcys (10^?15–10^?12 m²) and fault pressures fluctuate within 10–80% of overpressure ratio, the estimated oil volume in the Inglewood oil field (approximately 450 million barrels oil equivalent) can be accumulated in about 24 000 years, assuming a seismically induced fluid flow event occurs every 2000 years. This episodic petroleum migration model could be more geologically important than a continuous‐flow model, when considering the observed patterns of hydrocarbons and seismically active tectonic setting of the Los Angeles basin.     

A Model to Relate the Size of the Central Business District to the Population of a City

A set of dynamic models of CBD growth are developed. They hypothesize that growth rates depend upon the population growth rate together with the increasing unwillingness of people to travel to the city center as city size increases. A prediction of the model is that absolute decreases in CBD size can occur associated simply with population growth rather than technological change as is usually postulated. The models are tested using retail sales data for the United States. Good predictions are generally found, especially when the unique CBD of New York City is removed from the data set. However, the model which has the greatest theoretical validity relative to central place theory does not have the best fit to the data. Implications of this are discussed, along with those of utilizing transformations in regression models.     

FLUORINE IN FOSSILIZED BONE AND TOOTH: DISTRIBUTION AMONG SKELETAL TISSUES

Because of differences in their physical properties, bone, tooth dentine and tooth enamel react very differently during the course of fossilization. This relationship is shown clearly in the case of diagenetic introduction of fluorine wherein bone and dentine with high permeability and small apatite crystallite size contain 2–3 times the amount of fluorine as coexisting enamel with its low permeability and large crystallites. Smaller differences in the same sense are found within bone types from the same species, and care must be used in applying fluorine content methods even among bones from the same deposit.     

基于旅游数字足迹的西安旅游流网络结构研究

Web2.0时代,游客通过互联网获取信息、购买产品,而且还会分享游记、照片。这些游客留在网络上的游记、照片和其它痕迹都含有时空信息,称为"数字足迹"。本文以西安为例,利用游记和照片获取旅游数字足迹,采用数据挖掘方式提取时空信息,并结合社会网络分析法,试图总结西安国内散客旅游流时间及网络结构特征。结果表明,数字足迹研究的时间规律和其它调研结论基本一致;旅游节点间分布不均衡;旅游网络密度低、结构分层明显。本文基于旅游数字足迹的研究,具有很强的可推广价值,可为等旅游管理研究提供新思路。     

Evolution of porosity, permeability and fluid pressure in dilatant faults post-failure: implications for fluid flow and mineralization

Mineralization of brittle fault zones is associated with sudden dilation, and the corresponding changes in porosity, permeability and fluid pressure, that occur during fault slip events. The resulting fluid pressure gradients cause fluid to flow into and along the fault until it is sealed. The volume of fluid that can pass through the deforming region depends on the degree of dilation, the porosity and permeability of the fault and wall rocks, and the rate of fault sealing. A numerical model representing a steep fault cutting through a horizontal seal is used to investigate patterns of fluid flow following a dilatant fault slip event. The model is initialized with porosity, permeability and fluid pressure representing the static mechanical state of the system immediately after such an event. Fault sealing is represented by a specified evolution of porosity, coupled to changes in permeability and fluid pressure, with the rate of porosity reduction being constrained by independent estimates of the rate of fault sealing by pressure solution. The general pattern of fluid flow predicted by the model is of initial flow into the fault from all directions, followed by upward flow driven by overpressure beneath the seal. The integrated fluid flux through the fault after a single failure event is insufficient to account for observed mineralization in faults; mineralization would require multiple fault slip events. Downward flow is predicted if the wall rocks below the seal are less permeable than those above. This phenomenon could at least partially explain the occurrence of uranium deposits in reactivated basement faults that cross an unconformity between relatively impermeable basement and overlying sedimentary rocks.     

TELECOMMUNICATION EXTERNAL ECONOMIES,CITY SIZE AND OPTIMAL PRICING FOR TELECOMMUNICATIONS*

ABSTRACT. In this paper I make use of a city systems model to examine how telecommunications may affect cities in urban systems. The model offers an explanation for the observation that the share of employment in the communication-intensive producer-service sector increases with city size in the U.S. I suggest that external scale economies associated with metropolitan employment size, telecommunication network size and total number of intrametropolitan telecommunication contacts are possible explanations for this observation. I go on to suggest that the presence of telecommunication size and contact level external scale economies at the metropolitan level affects the optimal price that should be charged for local telecommunication services.     

On the Implications of a Stationary Urban Population For the Size Distribution of Cities

The paper analyzes the limiting case for a modified Yule-Simon model of city growth. The aim of the paper is primarily to reintroduce geographers to the notion of a closed system of cities, i.e., a system of cities where the aggregate population is stationary in size. The Yule-Simon model, while successful in dealing with the observed properties of open systems, is seen to break down for closed systems. Moreover, incorporating Simon's assumptions regarding intercity migration into the model produces implausible results. Also, the traditional approach of employing entropy-maximizing procedures assumes a certain pattern of intercity migration. This pattern, while not inherently implausible, does present features which are questionable. The authors conclude that an adequate theory for closed systems has yet to be developed.     

首府集中度和西部城市化模式探索

城市首位度是最早提出来对城市规模状况的指标描述,但随着经济的发展,处于第二位城市的人口数量的增加,首位度日益无法得力地描述城市体系的特征状况,更无法表述出地区人口在首府城市的集中程度,为此本文提出了城市首府集中度的概念,将首府集中度划分为不同的等级层次。对比中国与世界平均及中、俄间的首府度分布曲线,从而得出结论:中国大城市的发展潜力仍然很大,应进一步扩展和完善大城市。西部地区地广人稀,对比分析俄罗斯和西部的首府度状况,相应地提出西部开发模式。     

City and innovation: Different size,different strategy

The objective of this paper is to assess whether establishments' innovation performance and innovation strategies differ by the size of the city in which they are located. Using the Canadian 1999 Survey of Innovation database (establishment-based), it was found that the rate of innovation is not correlated with city-size, but when the innovation measure takes into account the importance of innovation, then the size of the city does matter. The results show that establishments belonging to smaller cities (with populations of less than 50,000) are less likely to be associated with a world-first innovation than those located in larger cities. Four innovation strategies have been retained—Private Source, R&D, Collaboration and Public Science Base paths—and the results show that the R&D path leads to the greatest increase in the estimated probability to be associated with a world-first innovation, for almost all sectors and all city sizes.     

The non-graded elementary school

The history of education in a number of industrialized countries during the first part of the 20th century testifies to the political will behind school centralization and the closure of small and non-graded rural elementary schools. A closer examination shows that school centralization throughout these countries can be associated with the development of a more unified educational system and that a unified school system is in turn seen as a political tool for the advancement of social welfare. In particular, this article discusses the development of the Norwegian non-graded elementary school. It examines the nature and the effects of the applied policies, and analyses the rationales – both political and educational – behind political decisions on education. The overall conclusions can be linked to and complement international research in this area.     

Agency Characteristics and the Use of Executive Orders

Past scholarship has offered varying explanations for why presidents choose to use executive orders. However, to this point, much of what we know of unilateral powers does not adequately address the role the bureaucracy plays in the president's decision. This research seeks to account for bureaucratic factors as a strategic presidential consideration in the employment of such directives. I classify executive orders from 1989–2012 based on which agency or agencies they apply to, and consider the importance of various characteristics (e.g. agency ideology, level of centralization, politicization, etc.) in determining which organs of the bureaucracy presidents will direct executive orders to generally. The results provide evidence that the White House directs fewer executive orders to agencies that have a politically independent leadership structure, and this result holds across a variety of measures judging an order's impact. The results demonstrate that the type of directive is crucial in determining a president's strategic decision to use executive orders, in line with previous research, and that agency centralization is one crucial component of this strategic calculation.     

Market size,occupational self‐selection,sorting, and income inequality

We develop a monopolistic competition model with heterogeneous agents who self‐select into occupations (entrepreneurs and workers) depending on innate ability. The effect of market size on the equilibrium occupational structure crucially hinges on properties of the lower tier utility function—its scale elasticity and relative love‐for‐variety. When combined with the underlying ability distribution, the share of entrepreneurs and income inequality can increase or decrease with market size. When extended to allow for the endogenous sorting of mobile agents between cities, numerical examples suggest that sorting may increase inequality within and between cities.     

Structural controls on hydrothermal flow in a segmented rift system, Taupo Volcanic Zone, New Zealand

Vigorous hydrothermal convection transfers 10 times the average continental heat flow through the central Taupo Volcanic Zone (TVZ), a region of active extension (approximately 8 mm year^?1) and productive rhyolitic volcanism. Over 20 high‐temperature (>250°C) geothermal fields occur within Quaternary pyroclastic basins, with convective circulation to depths of 7–8 km presumably extending through basement rocks. Parallel‐striking normal faults, fractures and dikes dissect the convective regime, interacting with fluids to either enhance or restrict flow according to the relative permeability of structure and host rock. In the basement, high bulk permeability is maintained by focussed flow through faults and associated fractures well oriented for reactivation in the prevailing stress field. In contrast, distributed flow through fault‐bounded compartments prevails within Quaternary basins, masking any signal of deeper structural control. Exceptions occur where more competent rocks are exposed at the surface. As in narrow magmatic rifts elsewhere, the extensional fabric is partitioned into discrete rift segments linked along strike by accommodation zones. Eighty per cent of TVZ geothermal fields correlate spatially with rift architecture, with 60% located in accommodation zones. We suggest that segmented rift fabrics generate bulk permeability anisotropy that is to some extent predictable, with rift segments characterized by enhanced axial flow, and accommodation zones characterized by locally enhanced vertical permeability that is tectonically maintained. This provides a plausible explanation for the common occurrence of geothermal fields within accommodation zones and their notable absence within densely faulted rift segments. Maintenance of structural permeability in zones of active hydrothermal precipitation necessarily requires repeated brittle failure. Geothermal plumes therefore exploit tectonically maintained permeability within accommodation zones, with rift segments functioning mostly as drawdown regions. The influence of rift architecture on flow paths has important implications for geothermal extraction and epithermal mineral exploration within the TVZ and other structurally segmented hydrothermal systems, both active and extinct.     

The Mortality of Things: Correlates of Use Life in Wola Material Culture Using Age-at-Census Data

How long ancient artifacts lasted affects the composition of archaeological assemblages. Some research suggests that longevity or use life relates to size and other artifact properties, but we know less than we should about what determines use life. An ethnographic census of Wola objects from highland Papua New Guinea recorded artifact age. From these data we use Hildebrand and Hagstrum's method to estimate mean use life. It does not covary generally with object size as in previous studies but does with commodity value. Among arrows alone, use life covaries with object size. Results complicate in some respects and clarify in others our growing understanding of what determines artifact use life.     

Old kingdom community organization in the Western Egyptian Delta

Old Kingdom Egypt has traditionally been regarded as distinctive among early civilizations in such characteristics as its largely non‐urban settlement patterns, extreme centralization of wealth and power in elites, and massive stability in its administrative institutions. But these characterizations are based almost entirely on documentary sources. Few Old Kingdom sites except those associated with mortuary cults have been excavated. Excavations at Kom el‐Hisn, in the western Egyptian Delta, have produced evidence about the economic organization and functioning of a rural Old Kingdom settlement that can be related to various hypotheses about the nature of Old Kingdom economic institutions.