316 research outputs found
Stamp duty on shares and its effect on share prices
This paper provides a discussion of stamp duty and its effects. This is followed by an empirical study using changes in the rate of stamp duty in the UK as natural experiments. Because shares will be affected differently depending on how frequently they are traded, we can employ a difference-in-differences methodology. We find that the announcements of cuts in stamp duty had a significant and positive effect on the price of more frequently traded shares compared to other shares. As expected under the efficient markets hypothesis, the implementation of cuts (when at a different date from the announcement) did not affect returns differentially.Stamp duty, transaction tax, Tobin-tax, natural experiment, tax reform
From Colonial Cargo to Global Containers: An Episodic Historical Geography of Manila's Waterfront
From Colonial Cargo to Global Containers narrates an episodic historical geography of the Port of Manila. The dissertation examines a series of key moments that transformed the port’s social and built environments: the onset and early years of American colonialism (1898-1905), the first five years of Philippine independence (1946-1950), and politically significant moments of harbor-side history prior to the declaration of Martial Law in the Philippines (1954-1972). Ethnographic vignettes and interviews with Manila’s cargo truck drivers bookend the project’s historical chapters and archival work. The dissertation’s analysis of decades of Philippine political change remains bounded by its geographic focus on political, social, and labor histories as they unfold mostly on and around the city’s wharves and piers. Across these eras, the research examines events in which the port and its stevedores and longshoremen were thrust into the national and international political spotlight. Manila’s docks featured prominently in the scenes of early American empire, local and global anti-communism from 1946-1950, and national trade union and electoral politics in the decades that followed. In each of these episodes, the management and control of port space and labor aimed to secure far more than the smooth flow of imports and exports. Thus, the dissertation aims to understand the port as not simply a bustling node of trade but rather a political space where power is historically secured, reproduced, contested, and resisted. More broadly, the research attests to the importance of critical geographic studies of particular landscapes and socio-spatial change over time.Doctor of Philosoph
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Frost fairs, sunspots and the Little Ice Age
Mike Lockwood, Mat Owens, Ed Hawkins, Gareth S. Jones and Ilya Usoskin examine the links between the solar Maunder minimum, the Little Ice Age and the freezing of the River Thame
Investigations at Kimmeridge Bay by the Dorset Alum and Copperas Industries Project
Archaeological investigations were carried out on behalf of the Poole Harbour Heritage Project in Kimmeridge Bay between 2009 and 2010, as part of a project researching the Dorset Alum and Copperas industries. There is documentary evidence for alum production at Kimmeridge in 1569 by John Clavell and 1605-1617 by William Clavell, but the precise location of their works is not known. Earthwork survey revealed the remains of three linked ponds with associated dams and sluices, industrial deposits, and a number of stone and timber structures along the shoreline. The ponds were most likely constructed as part of the early-seventeenth-century alum works. Examination of eroding industrial deposits along the shoreline (at SY 9088 7880) revealed buried beach deposits overlain by an extensive layer of burnt shale and shale ash that may have derived from the earliest alum works. This was sealed by clay and stone structures that may have formed part of a former quay or jetty perhaps also related to William Clavell's industrial ventures. This was buried beneath tips of burnt shale waste, probably relating to nineteenth-century activity. Exploratory excavations and geophysical survey were undertaken around the toilet block (centred on SY 9103 7878) where brick-built furnaces had been previously discovered, but this revealed that the archaeological remains were not extensive. Part of two flues and associated firing pits were found, probably related to the previously discovered furnaces, but they appeared unused. No dating evidence was recovered and no definite link to alum production was found
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Hourly weather observations from the Scottish Highlands (1883–1904) rescued by volunteer citizen scientists
Weather observations taken every hour during the years 1883–1904 on the summit of Ben Nevis (1345 m above sea level) and in the town of Fort William in the Scottish Highlands have been transcribed from the original publications into digital form. More than 3,500 citizen scientist volunteers completed the digitization in less than 3 months using the WeatherRescue.org website. Over 1.5 million observations of atmospheric pressure, wet‐ and dry‐bulb temperatures, precipitation and wind speed were recovered. These data have been quality controlled and are now made openly available, including hourly values of relative humidity derived from the digitized dry‐ and wet‐bulb temperatures using modern hygrometric algorithms. These observations are one of the most detailed weather data collections available for anywhere in the UK in the Victorian era. In addition, 374 observations of aurora borealis seen by the meteorologists from the summit of Ben Nevis have been catalogued and this has improved the auroral record for studies of space weather
Ultrafast 2D-IR spectroscopy of intensely optically scattering pelleted solid catalysts
ACKNOWLEDGMENTS This work was supported by a UKRI Future Leaders Fellowship grant (Grant No. MR/S015574/1), STFC-UKRI program access to CLF-ULTRA (Grant No. LSF1828), direct access to CLF-ULTRA (Grant Nos. Apps 17330043 and 19130012), and a group residency in the Research Complex at Harwell (RCaH). The authors are grateful to Kathryn Welsby, Ivalina Minova, and Santhosh Matam for support early in the project with samples and the Linkam cell. Mr. John Still of the School of Geosciences, University of Aberdeen is thanked for the SEM images, and Kieran Farrell/Martin Zanni is thanked for the discussion about the polarizations of the beams creating the thermal transientsPeer reviewedPublisher PD
Forecasting Evaluation of WindSat in the Coastal Environment
WindSat has demonstrated that measurements from polarimetric space-based microwave radiometers can be used to retrieve global ocean surface vector winds. Since the date of launch in 2003, substantial incremental improvements have been made to WindSat data processing, calibration, and retrieval algorithms. The retrievals now have higher resolution, improved wind vector ambiguity removal, and enhanced capability to represent high winds. Utilization of WindSat retrievals (wind vectors, total precipitable water, rainrate and sea surface temperature) will be demonstrated in the context of operational weather forecasting applications, especially the monitoring of topographically-forced winds. Examples will be presented from various parts of the world, including inland seas, midlatitude oceans, the tropics, and the United States. We will illustrate retrievals in extreme high- and extreme low-wind regimes, both of which can be problematic. Rain contamination will be addressed. We will include a comparison of WindSat vector maps to corresponding maps from the QuikScat scatterometer. We will discuss how near-realtime data from WindSat is being transitioned to specific offices within the National Weather Service
Dynamic Control Flow in Large-Scale Machine Learning
Many recent machine learning models rely on fine-grained dynamic control flow
for training and inference. In particular, models based on recurrent neural
networks and on reinforcement learning depend on recurrence relations,
data-dependent conditional execution, and other features that call for dynamic
control flow. These applications benefit from the ability to make rapid
control-flow decisions across a set of computing devices in a distributed
system. For performance, scalability, and expressiveness, a machine learning
system must support dynamic control flow in distributed and heterogeneous
environments.
This paper presents a programming model for distributed machine learning that
supports dynamic control flow. We describe the design of the programming model,
and its implementation in TensorFlow, a distributed machine learning system.
Our approach extends the use of dataflow graphs to represent machine learning
models, offering several distinctive features. First, the branches of
conditionals and bodies of loops can be partitioned across many machines to run
on a set of heterogeneous devices, including CPUs, GPUs, and custom ASICs.
Second, programs written in our model support automatic differentiation and
distributed gradient computations, which are necessary for training machine
learning models that use control flow. Third, our choice of non-strict
semantics enables multiple loop iterations to execute in parallel across
machines, and to overlap compute and I/O operations.
We have done our work in the context of TensorFlow, and it has been used
extensively in research and production. We evaluate it using several real-world
applications, and demonstrate its performance and scalability.Comment: Appeared in EuroSys 2018. 14 pages, 16 figure
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