Histological insights into the pathogenesis of post‐Roux‐en‐Y hyperinsulinaemic hypoglycaemia

Background β‐cell hyperplasia has been implicated in the aetiology of post Roux‐en‐Y gastric bypass hyperinsulinaemic hypoglycaemia, but the pathogenesis of this condition is still unclear. Case report We report a case of a 52‐year‐old man with post‐Roux‐en‐Y gastric bypass hyperinsulinaemic hypoglycaemia who underwent distal pancreatectomy to alleviate his symptoms. Pancreatic histopathology showed chronic pancreatitis with a corresponding loss of exocrine tissue and islet retention. Amyloid deposition was found in pancreatic islets. These features are more typically associated with Type 2 diabetes. Discussion This case highlights the potential multifactorial pathogenesis of symptomatic hypoglycaemia after Roux‐en‐Y gastric bypass. What's new? We present a case of a patient with post Roux‐en‐Y hypoglycaemia and pancreatic histology typically associated with diabetes. We show that hyperinsulinaemic hypoglycaemia has a multifactorial aetiology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109602/1/dme12571.pd

Hot dense capsule implosion cores produced by z-pinch dynamic hohlraum radiation

Hot dense capsule implosions driven by z-pinch x-rays have been measured for the first time. A ~220 eV dynamic hohlraum imploded 1.7-2.1 mm diameter gas-filled CH capsules which absorbed up to ~20 kJ of x-rays. Argon tracer atom spectra were used to measure the Te~ 1keV electron temperature and the ne ~ 1-4 x10^23 cm-3 electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak compression values of Te, ne, and symmetry, indicating reasonable understanding of the hohlraum and implosion physics.Comment: submitted to Phys. Rev. Let

Intra- and inter-firm dynamics in combinatorial knowledge bases

[EN] Research on innovation has often concentrated on a narrow set of sectors and activities, and on the experiences of the most advanced regions in the world. However, innovation, when defined in a broad sense, incorporates a variety of processes and outputs that cut across organisational, sectoral, territorial and knowledge boundaries. This paper seeks to make a contribution to this literature by focusing on the experiences of less developed regions, and by examining how different knowledge bases contribute to technological upgrading and higher added value for firms. It argues that in regions where access to advanced knowledge and technology is restricted, or where firms do not have the absorptive capacity to access, absorb and exploit such knowledge, combining existing knowledge in innovative ways may be the best strategy for firms to become more innovative and competitive. It also argues that this combination can happen through vertical integration within the firm, or by the creation and maintenance of inter-firm mechanisms that stimulate knowledge dissemination. These themes are discussed by drawing on the evolution of the wine industry in three Portuguese regions. These regions have all experienced different trajectories, in terms of the renewal of their wine industry, and it is argued that this is in part the result of endogenous regional characteristics.This work was supported by an Early Career Grant by the Regional Studies Association and by the German Research Foundation/European Science Foundation [grant number 10-ECRP-007].Marques, P. (2019). Intra- and inter-firm dynamics in combinatorial knowledge bases. European Urban and Regional Studies. 26(2):186-204. https://doi.org/10.1177/0969776418779116S186204262Asheim, B. T., Boschma, R., & Cooke, P. (2011). Constructing Regional Advantage: Platform Policies Based on Related Variety and Differentiated Knowledge Bases. Regional Studies, 45(7), 893-904. doi:10.1080/00343404.2010.543126Balland, P.-A., & Rigby, D. (2016). The Geography of Complex Knowledge. Economic Geography, 93(1), 1-23. doi:10.1080/00130095.2016.1205947Christopherson, S., & Clark, J. (2007). Power in Firm Networks: What it Means for Regional Innovation Systems. Regional Studies, 41(9), 1223-1236. doi:10.1080/00343400701543330Cusmano, L., Morrison, A., & Rabellotti, R. (2010). Catching up Trajectories in the Wine Sector: A Comparative Study of Chile, Italy, and South Africa. World Development, 38(11), 1588-1602. doi:10.1016/j.worlddev.2010.05.002Dosi, G., Faillo, M., & Marengo, L. (2008). Organizational Capabilities, Patterns of Knowledge Accumulation and Governance Structures in Business Firms: An Introduction. Organization Studies, 29(8-9), 1165-1185. doi:10.1177/0170840608094775Giuliani, E. (2007). The selective nature of knowledge networks in clusters: evidence from the wine industry. Journal of Economic Geography, 7(2), 139-168. doi:10.1093/jeg/lbl014Giuliani, E., & Bell, M. (2005). The micro-determinants of meso-level learning and innovation: evidence from a Chilean wine cluster. Research Policy, 34(1), 47-68. doi:10.1016/j.respol.2004.10.008Giuliani, E., Morrison, A., & Rabellotti, R. (2011). Innovation and Technological Catch-Up. doi:10.4337/9780857930514Grant, R. M. (1996). Toward a knowledge-based theory of the firm. Strategic Management Journal, 17(S2), 109-122. doi:10.1002/smj.4250171110Halkier, H., James, L., Dahlström, M., & Manniche, J. (2012). Knowledge Dynamics, Regions and Public Policy. European Planning Studies, 20(11), 1759-1766. doi:10.1080/09654313.2012.723419Hatch, C. J. (2013). Competitiveness by Design: An Institutionalist Perspective on the Resurgence of a «Mature» Industry in a High-Wage Economy. Economic Geography, 89(3), 261-284. doi:10.1111/ecge.12009Helfat, C. E. (2015). Vertical firm structure and industry evolution. Industrial and Corporate Change, 24(4), 803-818. doi:10.1093/icc/dtv027Malerba, F., Nelson, R., Orsenigo, L., & Winter, S. (2008). Vertical integration and disintegration of computer firms: a history-friendly model of the coevolution of the computer and semiconductor industries. Industrial and Corporate Change, 17(2), 197-231. doi:10.1093/icc/dtn001Manniche, J. (2012). Combinatorial Knowledge Dynamics: On the Usefulness of the Differentiated Knowledge Bases Model. European Planning Studies, 20(11), 1823-1841. doi:10.1080/09654313.2012.723423Manniche, J., Moodysson, J., & Testa, S. (2016). Combinatorial Knowledge Bases: An Integrative and Dynamic Approach to Innovation Studies. Economic Geography, 93(5), 480-499. doi:10.1080/00130095.2016.1205948Marques, P. (2017). From toys to automobiles: foreign investment, firm heterogeneity and intermediaries in a Portuguese industry. European Planning Studies, 25(8), 1375-1393. doi:10.1080/09654313.2017.1303822Marques, P. (2017). Human capital and university–business interactions: an example from the wine industry. Regional Studies, Regional Science, 4(1), 154-160. doi:10.1080/21681376.2017.1341818Martin, R., & Moodysson, J. (2011). Comparing knowledge bases: on the geography and organization of knowledge sourcing in the regional innovation system of Scania, Sweden. European Urban and Regional Studies, 20(2), 170-187. doi:10.1177/0969776411427326Martin, R., & Sunley, P. (2003). Deconstructing clusters: chaotic concept or policy panacea? Journal of Economic Geography, 3(1), 5-35. doi:10.1093/jeg/3.1.5Moulaert, F., & Sekia, F. (2003). Territorial Innovation Models: A Critical Survey. Regional Studies, 37(3), 289-302. doi:10.1080/0034340032000065442Pina, K., & Tether, B. S. (2016). Towards understanding variety in knowledge intensive business services by distinguishing their knowledge bases. Research Policy, 45(2), 401-413. doi:10.1016/j.respol.2015.10.005Polenske, K. R. (Ed.). (2007). The Economic Geography of Innovation. doi:10.1017/cbo9780511493386Rabellotti, R., & Schmitz, H. (1999). The Internal Heterogeneity of Industrial Districts in Italy, Brazil and Mexico. Regional Studies, 33(2), 97-108. doi:10.1080/00343409950122909Tödtling, F., & Grillitsch, M. (2015). Does Combinatorial Knowledge Lead to a Better Innovation Performance of Firms? European Planning Studies, 23(9), 1741-1758. doi:10.1080/09654313.2015.1056773WILLIAMSON, O. E. (1995). Hierarchies, Markets and Power in the Economy : An Economic Perspective. Industrial and Corporate Change, 4(1), 21-49. doi:10.1093/icc/4.1.2

Exploring the role of professional associations in collective learning in London and New York's advertising and law professional service firm clusters.

The value of regional economies for collective learning has been reported by numerous scholars. However often work has been criticised for lacking analytical clarity and failing to explore the architectures of collective learning and the role of the knowledge produced in making firms in a cluster economy successful. This paper engages with these problematics and investigates how collective learning is facilitated in the advertising and law professional service firm clusters in London and New York. It explores the role of professional associations and investigates how they mediate a collective learning process in each city. It argues that professional associations seed urban communities of practice that emerge outside of the formal activities of professional associations. In these communities individual with shared interests in advertising and law learn from one-another and are therefore able to adapt and evolve one-another approaches to common industry challenges. The paper suggests this is another form of the variation Marshall highlighted in relation to cluster-based collective learning. The paper also shows how the collective learning process is affected by the presence, absence and strength of an institutional thickness. It is therefore argued that a richer understanding of institutional affects is needed in relation to CL

Resonant holographic interferometry measurements of laser ablation plumes in vacuum, gas, and plasma environments

Resonant holographic interferometry and dye‐laser‐resonance‐absorption photography have been utilized to investigate the expansion of the laser ablation plumes produced by a KrF excimer laser beam (248 nm) focused onto an aluminum target (≊0.1 cm2, 2–6 J/cm2). Plume expansion was studied in vacuum and in background argon gas pressures of 14 mTorr, 52 mTorr, 210 mTorr, 1 Torr, and 35 Torr. The existing theory for the interpretation of resonant interferograms has been extended to account for Doppler shift effects, the diagnostic laser bandwidth, and the selective absorption of the laser beam. Absolute line densities in the range 4.3×1013–1.0×1015 cm−2 have been measured in the ablation plumes, which imply measured Al neutral densities of up to 1×1015 cm−3. The total number of Al neutral atoms in a plume has been measured to be ≊3×1014, which corresponds to a surface etch rate of ≊1 nm/pulse. Expansion velocities in the range 1.1–1.4 cm/μs were measured for the pressures ≤210 mTorr, while ≊0.3 cm/μs was measured for 1 Torr and ≊0.08 cm/μs was measured for 35 Torr. Ablation plume expansion into a 1 Torr rf argon plasma environment was compared with the expansion into a 1 Torr argon gas. The ablation plume appeared to expand and dissipate slightly faster in the plasma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70791/2/JAPIAU-76-9-5457-1.pd

Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air

A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative to inputs) in the oscillating flames, and caused maximum weakening. At 20 to 150 Hz, diffusion-rate-limited effects diminished, causing flames to "regain strengnth," and eventually become completely insensitive beyond 300 Hz. Detailed mechanistic understanding is needed. Overall, ethylene flames are remarkably resilient to dynamic extinction by oscillating inflows. They are the strongest, with the notable exception of H2. For HIFiRE tests, the 64%/36% surrogate disproportionally retains the high dynamic FS of ethylene, so the potential for loss of scramjet flameholding (flameout) due to low frequency oscillations is significantly mitigated

Third World gap year projects: Youth transitions and the mediation of risk

This is the post-print version of the final published article. The definitive, peer-reviewed and edited version of this article is available from the link below. Copyright @ 2008 Pion.In recent years in the UK there has been a great expansion in the number of young people travelling to Third World countries between school and university in order to participate as volunteers on structured gap year projects. Travel to such places is commonly perceived as ‘risky’, and takes young people outside the protective cocoon of UK health and safety legislation. One of the functions played by the providers of gap year projects is to mediate risk. On the basis of analysis of promotional literature, interviews with organisers of gap year projects, and focus groups of returned volunteers, in this paper I argue that the various strategies of risk mediation undertaken by gap year providers serve to reconcile modernising tendencies in UK society toward risk control and structure with postmodern inclinations towards individualisation and uncertainty