A survey of literature taught to slow learners in Massachusetts high schools.

Thesis (Ed.M.)--Boston Universit

Landscape response to Pleistocene-Holocene precipitation change in the Western Cordillera, Peru: 10Be concentrations in modern sediments and terrace fills

The landscape response to climate change is frequently investigated with models because natural experiments on geologic timescales are rare. In Quebrada Veladera, in the western Andes Mountains, the formation of alluvial terraces during periods of high precipitation presents opportunities for such an experiment. We compare drainage-average erosion rates during Pleistocene terrace deposition with Holocene rates, using cosmogenic 10Be samples for seven pairs of quartz sand taken from the trunk and tributaries of Quebrada Veladera and adjacent terraces. Each pair consists of sediment collected from the modern channel and excavated from an adjacent fill terrace. The terrace fill was deposited at ~16 ka and preserved an isotopic record of paleoerosion rates in the Late Pleistocene. Modern sands yield 10Be concentrations between 1.68 × 105 and 2.28 × 105 atoms/g, corresponding to Holocene erosion rates between 43 ± 3 and 58 ± 4 mm/kyr. The 10Be concentrations in terrace sands range from 9.46 × 104 to 3.73 × 105 atoms/g, corresponding to paleoerosion rates from 27 ± 2 to 103 ± 8 mm/kyr. Smaller, upstream tributaries show a substantial decline in erosion rate following the transition from a wet to dry climate, but larger drainage areas show no change. We interpret this trend to indicate that the wetter climate drove landscape dissection, which ceased with the return to dry conditions. As channel heads propagated upslope, erosion accelerated in low-order drainages before higher-order ones. This contrast disappeared when the drainage network ceased to expand; at that point, erosion rates became spatially uniform, consistent with the uniformity of modern hillslope gradients. Key Points Landscape response to climate change evaluated with 10Be erosion rates Wetter climate associated with rapid erosion in smaller, upstream drainages Drier, Holocene climate associated with spatially uniform erosion rates ©2013. American Geophysical Union. All Rights Reserved

Greenhouse Gas Emissions From Two Contrasting Beef Systems from Birth to Slaughter in Eastern Nebraska

Over the last 15 years, the increase in land use for corn and soybean has come at the expense of acres of grasslands and perennial forages employed in conventional beef-production systems. Implementing alternative cow-calf production systems into existing cropping systems may be a solution for reduced land availability and reducing total greenhouse gas emissions (GHG). Therefore, GHG from a conventional (CONV) pasture-based cattle production system with cows wintered on corn residue and summer grazing of brome pasture were compared to partial-confinement system (ALT) with cows and calves in a drylot during the summer and grazing cover crops and corn residue over the fall and winter. Eddy covariance and pen chambers were used to measure emissions from grazing and confinement scenarios. Measured CH4 and modeled N2O emissions totaled 7.5 ± 0.3 and 7.4 ± 0.3 kg CO2e kg-1 HCW for CONV and ALT production, respectively. There was a measured uptake of 233 g C m-2 and 98 g C m-2 from brome pasture and cover crop, respectively. Accounting for CH4 and N2O emissions using global warming potential (GWP) of 23 and 298 resulted in a net sink of 0.7 ± 0.2 kg CO2e kg-1 HCW for CONV and a net source of 16.7 ± 1.5 kg CO2e kg-1 HCW for ALT. The same calculations using global warming potential (GWP) of 4 and 234 resulted in a net sink of 10.9 ± 1.0 kg CO2e kg-1 HCW for CONV and a net source of 7.1 ± 1.5 kg CO2e kg-1 HCW for ALT. Carbon sequestration from perennial grasslands in the CONV was enough to offset all emissions and biogenic CO2. Annual forage grazed in the ALT system offset 42 to 72% of systems emissions depending on GWP metric used. These net carbon results open new horizons to livestock carbon balance research and give evidence that grazing systems sequester carbon emissions from cattle and in some cases are a carbon sink. Advisors: Galen E. Erickson and Andy Suyke

A Missed Opportunity to Improve Public Safety: Tbe Case for Improved Sanctioning of Unlawful Use of Weapon Arrests in Chicago

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Transitioning From Relational to Nosql: a Case Study

Data storage requirements have increased dramatically in recent years due to the explosion in data volumes brought about by the Web 2.0 era. Changing priorities for database system requirements has seen NoSQL databases emerge as an alternative to relational database systems that have dominated this market for over 40 years. Web-enabled, always on applications mean availability of the database system is critically important as any downtime can translate in to unrecoverable financial loss. Cost is also hugely important in this era where credit is difficult to obtain and organizations look to get the maximum from their IT infrastructure from the least amount of investment. The purpose of this study is to evaluate the current NoSQL market and assess its suitability as an alternative to a relational database. The research will look at a case study of a bulletin board application that uses a relational database for data storage and evaluate how such an application can be converted to using a NoSQL database. This case study will also be used to assess the performance attributes of a NoSQL database when implemented on a low cost hardware platform. The findings will provide insight to those who are considering making the switch from a relational database system to a NoSQL database system

The control of semi-autonomous robots

Includes bibliographical references.Robotic soccer is an international area of research which involves multiple robots collaborating in an adversarial and dynamic environment. Although many different forms gf robotic soccer are played, the University of Cape Town (UCT) chose the RoboCup small» sized robot league, officially known as the F180 RoboSoccer league, as a means of pursuing robotics research within the institution. The robot soccer game is played between two teams of ï¬ ve robots on a carpeted surface that is 2.8 m long by 2.3 m wide. The robots have their own on-board controllers that execute instructions sent to them from a computer-based artiï¬ cial intelligence (AI) system. In order for the AI system to keep track of all the robots and the ball (an orange golf ball), a global vision system is utilised. This global vision system uses images captured from either one or multiple digital cameras mounted above the ï¬ eld of play to determine the position and orientation of the team's robots, the position of the other teams' robots and ï¬ nally the position of the ball. In the true spirit of competition and furthering research, the rules which govern F180 RoboSoccer league cover only the basic format of the game thereby leaving various aspects of the robots, global vision system and AI design open for development. Since there was no RoboSoccer research in existence at UCT prior to the inception of this researcher's Masters' thesis the task included both the establishment of this format of robotics research at the institution as well as the actual design and development of the robots and the associated components as outlined below. Developing a team of robots requires a wide array of knowledge and the research undertaken was accordingly broken into three key components; the design of the robots (which included their related electronics and on-board controller), the design of a vision system and the design of an Al system. The main focus of this author's work was on the design of the robots as well as the overall structuring and integration of the UCT F180 RoboSoccer team. In addition, the areas of the global vision system and AI system that were covered within the scope of this thesis, are also presented. Prototypes were developed and in the ï¬ rst the main emphasis was placed on the movement of the robot, with the design of the kicking mechanism only occurring subsequent to this. After the ï¬ rst competition in 2002, this ï¬ rst design was abandoned in favour of developing a simpler robot with which to continue development. This simpler robot became the second prototype which, after testing, was reï¬ ned into the competition robot for 2003. During this period, the Al and global vision systems were developed by undergraduate thesis students. This research was then incorporated where applicable and, ï¬ nally, the residual problem areas were again addressed by a collaboration of staff and students. Whilst the design and implementation of the robots was very successful, the vision system was not successfully implemented before the competition in 2003. Although an autonomous game of soccer was not successfully played in the 2003 competition, the UCT F180 RoboSoccer team had made a great deal of progress towards this goal and, consequently, a strong foundation for future robotic soccer research within UCT has been established