Interdisciplinary (retail) research: The business of geography and the geography of business

NoAt the 2005 British Academy of Management conference several well-known economic geographers, including Neil Wrigley, Gordon Clark, and Susan Christopherson, called for management researchers to engage with economic geographers on interrelated geographical and managerial issues in the study of (retail) firms. In this commentary we reflect upon the present geography -management interface.We begin by considering the term `interdisciplinary research' and its relationship to any management - geography interface. This is followed by a context-specific discussion of international retailing and the role of research on the retail transnational corporation (TNC) in developing an interdisciplinary agenda. This commentary represents an initial more business and management focused response to the call from geography academics for more/better interdisciplinary research at the geography - management interface

Platelet-Induced Clumping of Plasmodium falciparum–Infected Erythrocytes from Malawian Patients with Cerebral Malaria—Possible Modulation In Vivo by Thrombocytopenia

Platelets may play a role in the pathogenesis of human cerebral malaria (CM), and they have been shown to induce clumping of Plasmodium falciparum–parasitized red blood cells (PRBCs) in vitro. Both thrombocytopenia and platelet-inducedPRBCclumping are associated with severe malaria and, especially, withCM.In the present study, we investigated the occurrence of the clumping phenomenon in patients with CM by isolating and coincubating their plasma and PRBCs ex vivo. Malawian children with CM all had low platelet counts, with the degree of thrombocytopenia directly proportional to the density of parasitemia. Plasma samples obtained from these patients subsequently induced weak PRBC clumping. When the assays were repeated, with the plasma platelet concentrations adjusted to within the physiological range considered to be normal, massive clumping occurred. The results of this study suggest that thrombocytopenia may, through reduction of platelet-mediated clumping of PRBCs, provide a protective mechanism for the host during CM

Can we use postal surveys with anonymous testing to monitor chlamydia prevalence in young women in England? Pilot study incorporating randomised controlled trial of recruitment methods

OBJECTIVES: Chlamydia prevalence in the general population is a potential outcome measure for the evaluation of chlamydia control programmes. We carried out a pilot study to determine the feasibility of using a postal survey for population-based chlamydia prevalence monitoring. METHODS: Postal invitations were sent to a random sample of 2000 17-year-old to 18-year-old women registered with a general practitioner in two pilot areas in England. Recipients were randomised to receive either a self-sampling kit (n=1000), a self-sampling kit and offer of £5 voucher on return of sample (n=500) or a self-sampling kit on request (n=500). Participants returned a questionnaire and self-taken vulvovaginal swab sample for unlinked anonymous Chlamydia trachomatis testing. Non-responders were sent a reminder letter 3 weeks after initial invitation. We calculated the participation rate (number of samples returned/number of invitations sent) and cost per sample returned (including cost of consumables and postage) in each group. RESULTS: A total of 155/2000 (7.8%) samples were returned with consent for testing. Participation rates varied by invitation group: 7.8% in the group who were provided with a self-sampling kit, 14% in the group who were also offered a voucher and 1.0% in the group who were not sent a kit. The cost per sample received was lowest (£36) in the group who were offered both a kit and a voucher. CONCLUSIONS: The piloted survey methodology achieved low participation rates. This approach is not suitable for population-based monitoring of chlamydia prevalence among young women in England

Tunable magnetic exchange interactions in manganese-doped inverted core/shell ZnSe/CdSe nanocrystals

Magnetic doping of semiconductor nanostructures is actively pursued for applications in magnetic memory and spin-based electronics. Central to these efforts is a drive to control the interaction strength between carriers (electrons and holes) and the embedded magnetic atoms. In this respect, colloidal nanocrystal heterostructures provide great flexibility via growth-controlled `engineering' of electron and hole wavefunctions within individual nanocrystals. Here we demonstrate a widely tunable magnetic sp-d exchange interaction between electron-hole excitations (excitons) and paramagnetic manganese ions using `inverted' core-shell nanocrystals composed of Mn-doped ZnSe cores overcoated with undoped shells of narrower-gap CdSe. Magnetic circular dichroism studies reveal giant Zeeman spin splittings of the band-edge exciton that, surprisingly, are tunable in both magnitude and sign. Effective exciton g-factors are controllably tuned from -200 to +30 solely by increasing the CdSe shell thickness, demonstrating that strong quantum confinement and wavefunction engineering in heterostructured nanocrystal materials can be utilized to manipulate carrier-Mn wavefunction overlap and the sp-d exchange parameters themselves.Comment: To appear in Nature Materials; 18 pages, 4 figures + Supp. Inf

Gravity waves and the LHC: Towards high-scale inflation with low-energy SUSY

It has been argued that rather generic features of string-inspired inflationary theories with low-energy supersymmetry (SUSY) make it difficult to achieve inflation with a Hubble scale H > m_{3/2}, where m_{3/2} is the gravitino mass in the SUSY-breaking vacuum state. We present a class of string-inspired supergravity realizations of chaotic inflation where a simple, dynamical mechanism yields hierarchically small scales of post-inflationary supersymmetry breaking. Within these toy models we can easily achieve small ratios between m_{3/2} and the Hubble scale of inflation. This is possible because the expectation value of the superpotential relaxes from large to small values during the course of inflation. However, our toy models do not provide a reasonable fit to cosmological data if one sets the SUSY-breaking scale to m_{3/2} < TeV. Our work is a small step towards relieving the apparent tension between high-scale inflation and low-scale supersymmetry breaking in string compactifications.Comment: 21+1 pages, 5 figures, LaTeX, v2: added references, v3: very minor changes, version to appear in JHE

Is chlamydia screening and testing in Britain reaching young adults at risk of infection? Findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

In the context of widespread opportunistic chlamydia screening among young adults, we aimed to quantify chlamydia testing and diagnosis among 16-24 year olds in Britain in relation to risk factors for prevalent chlamydia infection

Association of Amyloid Pathology With Myelin Alteration in Preclinical Alzheimer Disease

IMPORTANCE: The accumulation of aggregated β-amyloid and tau proteins into plaques and tangles is a central feature of Alzheimer disease (AD). While plaque and tangle accumulation likely contributes to neuron and synapse loss, disease-related changes to oligodendrocytes and myelin are also suspected of playing a role in development of AD dementia. Still, to our knowledge, little is known about AD-related myelin changes, and even when present, they are often regarded as secondary to concomitant arteriosclerosis or related to aging. OBJECTIVE: To assess associations between hallmark AD pathology and novel quantitative neuroimaging markers while being sensitive to white matter myelin content. DESIGN, SETTING AND PARTICIPANTS: Magnetic resonance imaging was performed at an academic research neuroimaging center on a cohort of 71 cognitively asymptomatic adults enriched for AD risk. Lumbar punctures were performed and assayed for cerebrospinal fluid (CSF) biomarkers of AD pathology, including β-amyloid 42, total tau protein, phosphorylated tau 181, and soluble amyloid precursor protein. We measured whole-brain longitudinal and transverse relaxation rates as well as the myelin water fraction from each of these individuals. MAIN OUTCOMES AND MEASURES: Automated brain mapping algorithms and statistical models were used to evaluate the relationships between age, CSF biomarkers of AD pathology, and quantitative magnetic resonance imaging relaxometry measures, including the longitudinal and transverse relaxation rates and the myelin water fraction. RESULTS: The mean (SD) age for the 19 male participants and 52 female participants in the study was 61.6 (6.4) years. Widespread age-related changes to myelin were observed across the brain, particularly in late myelinating brain regions such as frontal white matter and the genu of the corpus callosum. Quantitative relaxometry measures were negatively associated with levels of CSF biomarkers across brain white matter and in areas preferentially affected in AD. Furthermore, significant age-by-biomarker interactions were observed between myelin water fraction and phosphorylated tau 181/β-amyloid 42, suggesting that phosphorylated tau 181/β-amyloid 42 levels modulate age-related changes in myelin water fraction. CONCLUSIONS AND RELEVANCE: These findings suggest amyloid pathologies significantly influence white matter and that these abnormalities may signify an early feature of the disease process. We expect that clarifying the nature of myelin damage in preclinical AD may be informative on the disease’s course and lead to new markers of efficacy for prevention and treatment trials

Alcohol affects neuronal substrates of response inhibition but not of perceptual processing of stimuli signalling a stop response

Alcohol impairs inhibitory control, including the ability to terminate an initiated action. While there is increasing knowledge about neural mechanisms involved in response inhibition, the level at which alcohol impairs such mechanisms remains poorly understood. Thirty-nine healthy social drinkers received either 0.4g/kg or 0.8g/kg of alcohol, or placebo, and performed two variants of a Visual Stop-signal task during acquisition of functional magnetic resonance imaging (fMRI) data. The two task variants differed only in their instructions: in the classic variant (VSST), participants inhibited their response to a “Go-stimulus” when it was followed by a “Stop-stimulus”. In the control variant (VSST_C), participants responded to the “Go-stimulus” even if it was followed by a “Stop-stimulus”. Comparison of successful Stop-trials (Sstop)>Go, and unsuccessful Stop-trials (Ustop)>Sstop between the three beverage groups enabled the identification of alcohol effects on functional neural circuits supporting inhibitory behaviour and error processing. Alcohol impaired inhibitory control as measured by the Stop-signal reaction time, but did not affect other aspects of VSST performance, nor performance on the VSST_C. The low alcohol dose evoked changes in neural activity within prefrontal, temporal, occipital and motor cortices. The high alcohol dose evoked changes in activity in areas affected by the low dose but importantly induced changes in activity within subcortical centres including the globus pallidus and thalamus. Alcohol did not affect neural correlates of perceptual processing of infrequent cues, as revealed by conjunction analyses of VSST and VSST_C tasks. Alcohol ingestion compromises the inhibitory control of action by modulating cortical regions supporting attentional, sensorimotor and action-planning processes. At higher doses the impact of alcohol also extends to affect subcortical nodes of fronto-basal ganglia- thalamo-cortical motor circuits. In contrast, alcohol appears to have little impact on the early visual processing of infrequent perceptual cues. These observations clarify clinically-important effects of alcohol on behaviour