Theoretical foundations of operational research

The conclusions of both Parts One and Two complement and reinforce each other. After outlining the ideals of OR, I set out in Part One to find and scrutinize the philosophical foundations upon which some leading operations researchers have claimed that these ideals could be implemented. In chapters 2, 3, and 4 I argue that adopting (respectively) the positivist, conventionalist and/or idealist philosophies as the theoretical foundations upon which to build an adequate theory of inquiry for the purposes of OR would force it to abandon its ideals. These philosophies are interpreted as attempts on the part of academic operational researchers to stave-off the open-ended ambiguity and anarchy of inquiry which an unqualified interpretation of OR's ideals could engender. These attempts to give substance to the ideals of OR all exert a strong bias against raising questions about the nature of the subject-matter with which OR deals, and it in largely on these grounds that they are rejected in chapter 5 because of the implications which this has for the ideals of OR. One conclusion of Part One is that OR needs protection from such philosophies, and that a realist-type alternative at least provides this. I conclude by raising the doubt whether philosophy can provide much more to OR. The other major conclusion is that OR needs to understand its subject-matter before it can reasonably hope to implement its ideals. Given the general bias which we find in Part One against seriously considering the subject-matter of OR, we enter Part Two with some trepidation. Notwithstanding the philosophical bias against it, it is clear that OR must have a conception of the nature of its subject-matter. However, OR's ideals can just as easily be lost by inadequate attention to this task. In Part Two the biases discovered in Part One come home to roost. The first attempt to provide the ideals of OR with a substance on the basis of which its ideals can be implemented in an objective fray turns out to be just that, i.e., metaphysical 'substance' in the guise of a theory of management. We see in chapter 6 that to the extent to which this theory moves beyond merely asserting that management would 'take care' of OR's need for an objective basis, it presupposes a social theory which would show how social systems by their nature (if properly constructed) embody this objectivity. This move is foreshadowed in chapter 3 where we see Kuhn (who is taken as an exemplar of conventionalist philosophy) finally resorting to this device to prop up his conventionalism, against the growing weight of subjectivity under which it threatened to sag into the jaws of positivism. The social theory on which such claims rest is given detailed consideration in. chapter 7. In chapter 7 I give serious consideration to the possibility that OR's social theory, if it has one at all, will be developed in reaction to what it sees as the "problem of order", because this problem can be seen as but another way of stating its ideals in a specifically social way. Stating OR ideals in this way orients them directly to at least one aspect of the question of the nature of OR's subject-matter. We see that by employing, Durkheim's account of and solution to the social problem of order as a basis for comparison with OR (first as a homomorphism. and later as an isomorphism) that we are able to gain quite a firm grip on OR's social theory (and, hence, its grasp of its subject-matter). We see that this theory, although providing a justification for OR's theory of management (especially in its modern form), it is itself inadequate. The basis of the inadequacy, most fundamentally, is that the theory in question presupposes the very thing, that should be in question, namely, the nature of the social collective. I conclude with a specific illustration of the impact of this theory on the ideal of OR by analysing the inadequate treatment of power and conflict which it allows

Renal outcome of type 2 diabetes in South Africa - a 12-year follow-up study

Aims. Previous studies of type 2 diabetes mellitus have indicated a benign renal outcome after long-term  follow-up. The aim of this study was to determine how often renal failure due to diabetic nephropathy was  a cause of death in patients with type 2 diabetes.Methods. Prospective observational study of 59 South African patients with type 2 diabetes over a 12-year period. During the study repeated clinical evaluations were accompanied by measurements of serum creatinine, serum cholesterol, random blood sugar, and urine protein/ creatinine ratios.Results. The mean duration of diabetes at the end of the study was 17.8 years. There was a wide variation in the time from clinical diagnosis of diabetes to macroprQteinuria (mean 9.7 years, SD 5.9, range 0- 21) and the rate of deterioration of renal function. This rate correlated with poor control of blood pressure, a glucose level of> 14 mmol/1, heavy proteinuria, a high retinopathy score, a body mass index of < 28 and the number of pack years of smoking. At the end of the study 47 patients (79.7%) had died. Of these deaths 17 (28.8%) were due to chronic renal failure.Conclusions. In contrast to other studies we have shown that in a developing country renal failure in  type 2 diabetic patients is a major cause of death. Determining the prognosis for an individual patient is difficult as there are wide ranges in the time of onset of proteinuria, the rise in serum creatinine and the time to ultimate progression to end-stage renal failure

Structural basis for the homotypic fusion of chlamydial inclusions by the SNARE-like protein IncA.

Many intracellular bacteria, including Chlamydia, establish a parasitic membrane-bound organelle inside the host cell that is essential for the bacteria\u27s survival. Chlamydia trachomatis forms inclusions that are decorated with poorly characterized membrane proteins known as Incs. The prototypical Inc, called IncA, enhances Chlamydia pathogenicity by promoting the homotypic fusion of inclusions and shares structural and functional similarity to eukaryotic SNAREs. Here, we present the atomic structure of the cytoplasmic domain of IncA, which reveals a non-canonical four-helix bundle. Structure-based mutagenesis, molecular dynamics simulation, and functional cellular assays identify an intramolecular clamp that is essential for IncA-mediated homotypic membrane fusion during infection

Immobilization of the Erupting Molar in the Syrian Hamster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67148/2/10.1177_00220345650440061901.pd

Slx8 removes Pli1-dependent protein-SUMO conjugates including SUMOylated Topoisomerase I to promote genome stability

Peer reviewedPublisher PD

The evolution of quantitative sensitivity

This work was supported by the National Science Foundation Graduate Research Fellowship Programme grant no. DGE-1419118 to S.E.K., and NSF 2000759 from the Division of Research on Learning in Formal and Informal Settings (DRL) to S.T.P., the Austrian Science Fund (FWF project no. P33928_B) to F.R., the Alfred P. Sloan Foundation Fellowship grant no. 220020300 to J.F.C., National Institutes of Health grant no. R01 HD085996 to J.F.C. and S.T.P. and the James S. McDonnell Foundation.The ability to represent approximate quantities appears to be phylogenetically widespread, but the selective pressures and proximate mechanisms favouring this ability remain unknown. We analysed quantity discrimination data from 672 subjects across 33 bird and mammal species, using a novel Bayesian model that combined phylogenetic regression with a model of number psychophysics and random effect components. This allowed us to combine data from 49 studies and calculate the Weber fraction (a measure of quantity representation precision) for each species. We then examined which cognitive, socioecological and biological factors were related to variance in Weber fraction. We found contributions of phylogeny to quantity discrimination performance across taxa. Of the neural, socioecological and general cognitive factors we tested, cortical neuron density and domain-general cognition were the strongest predictors of Weber fraction, controlling for phylogeny. Our study is a new demonstration of evolutionary constraints on cognition, as well as of a relation between species-specific neuron density and a particular cognitive ability. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.Publisher PDFPeer reviewe

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO