434 research outputs found
Big Data, Social Physics, and Spatial Analysis: The Early Years
This paper examines one of the historical antecedents of Big Data, the social physics movement. Its origins are in the scientific revolution of the 17th century in Western Europe. But it is not named as such until the middle of the 19th century, and not formally institutionalized until another hundred years later when it is associated with work by George Zipf and John Stewart. Social physics is marked by the belief that large-scale statistical measurement of social variables reveals underlying relational patterns that can be explained by theories and laws found in natural science, and physics in particular. This larger epistemological position is known as monism, the idea that there is only one set of principles that applies to the explanation of both natural and social worlds. Social physics entered geography through the work of the mid-20th-century geographer William Warntz, who developed his own spatial version called ââmacrogeography.ââ It involved the computation of large data sets, made ever easier with the contemporaneous development of the computer, joined with the gravitational potential model. Our argument is that Warntzâs concerns with numeracy, large data sets, machine-based computing power, relatively simple mathematical formulas drawn from natural science, and an isomorphism between natural and social worlds became grounds on which Big Data later staked its claim to knowledge; it is a past that has not yet passed
Big data, little history
Abstract The paper makes the argument that what is forgotten in the celebration of big data is history. Big data is presented as if it were disconnected from the past, removed from issues or problems that went before. I argue in this short commentary that the past remains potent for big data and that proponents ignore it at their peril. Rather than being a brand new approach, big data brings a series of problematic assumptions and practices first criticised 40 years ago by opponents of geography's quantitative revolution. Those assumptions, practices and criticisms are reviewed in the paper
The Great Debate in Mid-Twentieth-Century American Geography: Fred K. Schaefer vs. Richard Hartshorne
The mid-twentieth-century debate around whether geography should be ideographic, and descriptively study the unique, or nomothetic, and seek law-like explanatory generalizations, was sparked in 1953 by Fred K. Schaefer. Schaefer was a political refugee from Nazi Germany and not trained as a geographer. Nonetheless, he was a professor in the Geography Department at the University of Iowa, when he penned the paper that attacked Americaâs most famous and powerful geographer, Richard Hartshorne. Hartshorneâs celebrated book, The Nature of Geography (1939) defined, justified and genealogically fixed geography as an ideographic science, that is, âconcerned with the description and interpretation of unique cases. âŠ" (Hartshorne 1939, 449). Schaeferâs paper excoriated all of Hartshorneâs claims, both historical and philosophical. His alternative was the philosophy of logical positivism originating in Austria during the 1920s with a group of philosophers, scientists and mathematicians collectively known as the Vienna Circle. Logical positivism said that for any knowledge to be taken seriously as knowledge it must be expressible as a law-like generalization. When Hartshorne read Schaeferâs critique, he was apoplectic. He wrote two virulent replies denying all of Schaeferâs charges. Schaefer, though, was already dead so couldnât reply. But others did. Over the next decade some form of logical positivism took hold in the discipline and geography was never the same again
Hierarchical decomposition and simulation of manufacturing cells using Ada
A useful tool in the development of flexible automation is a system description language which can generate a complete func tional description of a manufacturing cell of arbitrary complexity. We propose a description system based on the concept of hierar chical decomposition utilizing the Ada programming language in conjunction with established diagrammatical decomposition methods. The distinguishing aspect of our work is that it takes advantage of certain features of Ada (such as type checking) to create a description that can be automatically verified for con sistency Simulation is often an indispensable tool in the develop ment of manufacturing systems. We show how a simulation of the operation of the manufacturing cell can be embedded in its description. Finally, we apply the methodology to a specific instance of a manufacturing cell.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68498/2/10.1177_003754978604600402.pd
Parent perspectives on the benefits and risks of child-livestock interactions
Growing up on a farm or ranch often involves interactions with livestock that present both potential risks and benefits to children. While these âchild-livestock interactionsâ contribute to the burden of agriculturally related injuries to youth in the United States, they may also result in improved immunological health and other benefits. Agricultural upbringings are also widely perceived to improve physical, cognitive, and skill development of children, contributing to a combination of potential benefits and risks known as the âfarm kid paradox.â Although previous studies show the health impacts of child-livestock interactions, less is known about the ways in which farm and ranch parents perceive the benefits and risks of these interactions, and how and why they choose to raise children around livestock. Our research addresses this gap by analyzing data from semi-structured interviews with 30 parents of children between the ages of 10â18 who produce beef cattle in Kansas. This research is part of a larger anthropological study of the benefits and risks of child-livestock interactions involving parents on beef and dairy operations in multiple states, along with agricultural safety and health professionals. The results offer insights into the experiences, practices, and perspectives of parents, outlining agricultural ways of life in which safety and relations to risk are shaped by patterns of production, family dynamics, values and habits, and other social and cultural dimensions. These insights deepen our understanding of parents' perceptions of both benefits and risks of agricultural childhoods
The journey effect: how travel affects the experiences of mental health in-patient service-users and their families
The qualitative study presented in this paper explored the perspectives of service-users, family members and staff about the impact of travel issues on the lives of mental health in-patients and carers. This topic was chosen because it was prioritised by members of Xplore, a service-user and carer research group, and has received little research attention. Travel problems were a significant issue for many service-users and carers, bound-up with mental health issues and the recovery experience. Travel facilitation through the funding of taxis and the provision of guides was appreciated. A few service-users and carers positively valued distancing from their previous home environment. The meaning of travel issues could only be understood in the context of individualsâ wider lives and relationships. The significance of the findings is discussed in relation to the social model of disability
Engineering a hyperactive TcBuster transposase for efficient gene delivery for cell therapy applications
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The mass assembly of galaxy groups and the evolution of the magnitude gap
We investigate the assembly of groups and clusters of galaxies using the
Millennium dark matter simulation and the associated gas simulations and
semi-analytic catalogues of galaxies. In particular, in order to find an
observable quantity that could be used to identify early-formed groups, we
study the development of the difference in magnitude between their brightest
galaxies to assess the use of magnitude gaps as possible indicators. We select
galaxy groups and clusters at redshift z=1 with dark matter halo mass M(R200) >
1E13/h Msun, and trace their properties until the present time (z=0). We
consider only the systems with X-ray luminosity L_X> 0.25E42/h^2 erg/s at z=0.
While it is true that a large magnitude gap between the two brightest galaxies
of a particular group often indicates that a large fraction of its mass was
assembled at an early epoch, it is not a necessary condition. More than 90% of
fossil groups defined on the basis of their magnitude gaps (at any epoch
between 0<z<1) cease to be fossils within 4 Gyr, mostly because other massive
galaxies are assembled within their cores, even though most of the mass in
their haloes might have been assembled at early times. We show that, compared
to the conventional definition of fossil galaxy groups based on the magnitude
gap Delta m(12)> 2 (in the R-band, within 0.5R200 of the centre of the group),
an alternative criterion Delta m(14)>2.5 (within the same radius) finds 50%
more early-formed systems, and those that on average retain their fossil phase
longer. However, the conventional criterion performs marginally better at
finding early-formed groups at the high-mass end of groups. Nevertheless, both
criteria fail to identify a majority of the early-formed systems.Comment: 16 pages, 11 figures, 2 tables. Accepted for publication in MNRA
The dark haloes of early-type galaxies in low-density environments: XMM-Newton and Chandra observations of NGC 57, NGC 7796 and IC 1531
We present analysis of Chandra and XMM-Newton observations of three
early-type galaxies, NGC 57, NGC 7796 and IC 1531. All three are found in very
low density environments, and appear to have no neighbours of comparable size.
NGC 57 has a halo of kT~0.9 keV, solar metallicity gas, while NGC 7796 and IC
1531 both have ~0.55 keV, 0.5-0.6 Zsol haloes. IC 1531 has a relatively compact
halo, and we consider it likely that gas has been removed from the system by
the effects of AGN heating. For NGC 57 and NGC 7796 we estimate mass, entropy
and cooling time profiles and find that NGC 57 has a fairly massive dark halo
with a mass-to-light ratio of 44.7 (4.0,-8.5) Msol/Lsol (1 sigma uncertainties)
at 4.75 Re. This is very similar to the mass-to-light ratio found for NGC 4555
and confirms that isolated ellipticals can possess sizable dark matter haloes.
We find a significantly lower mass-to-light ratio for NGC 7796, 10.6
(+2.5,-2.3) Msol/Lsol at 5 Re, and discuss the possibility that NGC 7796 hosts
a galactic wind, causing us to underestimate its mass.Comment: 14 pages, 9 figures, accepted for publication in MNRA
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Crypt fusion as a homeostatic mechanism in the human colon.
OBJECTIVE: The crypt population in the human intestine is dynamic: crypts can divide to produce two new daughter crypts through a process termed crypt fission, but whether this is balanced by a second process to remove crypts, as recently shown in mouse models, is uncertain. We examined whether crypt fusion (the process of two neighbouring crypts fusing into a single daughter crypt) occurs in the human colon. DESIGN: We used somatic alterations in the gene cytochrome c oxidase (CCO) as lineage tracing markers to assess the clonality of bifurcating colon crypts (n=309 bifurcating crypts from 13 patients). Mathematical modelling was used to determine whether the existence of crypt fusion can explain the experimental data, and how the process of fusion influences the rate of crypt fission. RESULTS: In 55% (21/38) of bifurcating crypts in which clonality could be assessed, we observed perfect segregation of clonal lineages to the respective crypt arms. Mathematical modelling showed that this frequency of perfect segregation could not be explained by fission alone (p<10-20). With the rates of fission and fusion taken to be approximately equal, we then used the distribution of CCO-deficient patch size to estimate the rate of crypt fission, finding a value of around 0.011 divisions/crypt/year. CONCLUSIONS: We have provided the evidence that human colonic crypts undergo fusion, a potential homeostatic process to regulate total crypt number. The existence of crypt fusion in the human colon adds a new facet to our understanding of the highly dynamic and plastic phenotype of the colonic epithelium.wellcome trust
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