The Variable Value Environment: Auctions and Actions

We model an environment, where bidders’ private values may change over time as a result of both costly private actions and exogenous shocks. Examples of private actions include investment and entry decisions; shocks might be due to exogenous changes in a potential buyer’s circumstances. We describe an efficient auction mechanism that maximizes the final value of the object to the winning bidder net of the total cost of investment by all agents. In particular, we show that, assuming that the auctioneer does not have full commitment power, costly signalling is necessary for efficient entry when agents receive private information both before and after they make the entry decision. To rule out pooling equilibria that coexist with the efficient equilibrium in the basic mechanism, we introduce a virtual-implementation-style mechanism that (i) is almost efficient; (ii) forces players to coordinate on the separating equilibrium; and (iii) is simple enough to be potentially useful in practice.auctions, efficient mechanism design

The Variable Value Environment: Auctions and Actions

This paper introduces and formally models the variable value environment and proposes an auction mechanism appropriate for it. In the variable value environment, bidders’ private values may change over time as a result of both private actions and exogenous shocks. Examples of private actions and exogenous shocks are complementary investments and exogenous changes in bidder's business, respectively. We consider a three-period model of the variable value environment where agents receive signals about their values in the first and the third periods and in the second period they take actions. This setting captures essential features of auctions of objects available for use at a future date (e. g. , a sale of a military base scheduled to close in a few years). We study mechanisms that lead to efficient allocations, i. e. those in which the final value of the object to the winning bidder net of the total cost of private actions undertaken by all agents is maximized. We characterize the first best allocation, and propose a mechanism that yields the first best allocation in equilibrium. This mechanism has an inefficient pooling equilibrium along with an efficient separating equilibrium. To rule out the pooling equilibrium, we introduce a class of e -efficient mechanisms that force players to coordinate on the separating equilibrium. We prove that one can always choose an e -efficient mechanism that yields an efficient allocation with probability arbitrarily close to one.

Healthcare professional’s guide to cardiopulmonary exercise testing

Cardiopulmonary exercise testing (CPEX) is a valuable clinical tool that has proven indications within the fields of cardiovascular, respiratory and pre-operative medical care. Validated uses include investigation of the underlying mechanism in patients with breathlessness, monitoring functional status in patients with known cardiovascular disease and pre-operative functional state assessment. An understanding of the underlying physiology of exercise, and the perturbations associated with pathological states, is essential for healthcare professionals to provide optimal patient care. Healthcare professionals may find performing CPEX to be daunting, yet this is often due to a lack of local expertise and guidance with testing. We outline the indications for CPEX within the clinical setting, present a typical protocol that is easy to implement, explain the key underlying physiological changes assessed by CPEX, and review the evidence behind its use in routine clinical practice. There is mounting evidence for the use of CPEX clinically, and an ever-growing utilisation of the test within research fields; a sound knowledge of CPEX is essential for healthcare professionals involved in routine patient care

Waterborne phenolic, triazine-based porous polymer particles for the removal of toxic metal ions

Highly functional and also highly porous materials are presenting great advantages for applications in energy storage, catalysis and separation processes, which is why a continuous development of new materials can be seen. To create a material combining the promising potential interactions of triazine groups with the electrostatic or hydrogen bonding interactions of phenolic groups, a completely new polymeric resin was synthesized. From an eco-friendly dispersion polymerization in water, a copolymer network was obtained, which includes nine hydroxyl groups and one s-triazine ring per repetition unit. The polymer forms highly porous particles with specific surface areas up to 531 ​m2/g and a negative streaming potential over a great pH range. The adsorption isotherms of Ni2+, Cd2+, and Pb2+ were studied in more detail achieving very good adsorption capacities (16 mg Ni2+/g, 24 mg Cd2+/g, and 90 mg Pb2+/g). Demonstrating excellent properties for adsorption applications. The adsorbent exhibited selectivity for the adsorption of Pb2+ over more commonly occurring but non-toxic metal ions such as Fe2+, Ca2+, Mg2+, and K+. Furthermore, reusability of the material was demonstrated by facile, quantitative desorption of adsorbed Pb2+ with a small amount of diluted HCl, circumventing organic chelators. Subsequently, adsorption was carried out without decrease in adsorption performance

Myeloid-related protein 8/14 complex describes microcirculatory alterations in patients with type 2 diabetes and nephropathy

<p>Abstract</p> <p>Background</p> <p>Inflammation contributes to cardiovascular complications in type 2 diabetes, which are often characterized by microvascular alterations. We investigated whether myeloid-related protein 8/14 complex (MRP8/14) secreted by transmigrating monocytes and granulocytes may represent a biomarker for microvascular alterations in patients with type 2 diabetes and nephropathy.</p> <p>Methods</p> <p>MRP8/14 was measured in 43 patients with type 2 diabetes and nephropathy. Additionally, the inflammatory markers Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were quantified. To detect microvascular alterations proteinuria and retinal vessel caliber were used as classical and novel marker, respectively. Proteinuria was quantified by protein-creatinine ratio (PCR); retinal vessel caliber was quantified after retina photography on digitalized retina pictures.</p> <p>Results</p> <p>MRP8/14 was positively associated with inflammation (<it>r </it>= 0.57), proteinuria (<it>r </it>= 0.40) and retinal arterial caliber (<it>r </it>= 0.48). Type 2 diabetic patients with MRP8/14 values above the median of 5.8 μg/ml demonstrated higher proteinuria and larger retinal artery caliber than patients with MRP8/14 values below the median (logPCR: -0.51 ± 0.52 versus -0.96 ± 0.46, <it>P </it>< 0.01; retinal artery lumen (μm): 178.3 ± 14.1 versus 162.7 ± 14.9 <it>P </it>< 0.01). Both groups did not differ with regard to metabolic factors and blood pressure. MRP8/14 was an independent predictor of retinal artery caliber in multivariate stepwise regression analysis (<it>β </it>= 0.607) and was positively associated with IL-6 (<it>r </it>= 0.57, <it>P </it>< 0.001) and TNF-α (<it>r </it>= 0.36, <it>P </it>< 0.05).</p> <p>Conclusion</p> <p>MRP8/14 – a marker for transendothelial migration – describes not only the state of inflammation in diabetic nephropathy, but additionally the degree of microvascular alterations in the glomerular and retinal bed. Therefore, MRP8/14 may be a potentially selective novel biomarker for microcirculatory defects in diabetic nephropathy.</p

Free Breathing Real-Time Cardiac Cine Imaging With Improved Spatial Resolution at 3 T

Objectives: The aim of this study was to evaluate free-breathing single-shot real-time cine imaging for functional cardiac imaging at 3 +/- with increased spatial resolution. Special emphasis of this study was placed on the influence of parallel imaging techniques. Materials and Methods: Gradient echo phantom images were acquired with GRAPPA and modified SENSE reconstruction using both integrated and separate reference scans as well as TGRAPPA and TSENSE. In vivo measurements were performed for GRAPPA reconstruction with an integrated and a separate reference scan, as well as TGRAPPA using balanced steady-state free precession protocols. Three clinical protocols, rtLRInt (T-res = 51.3 milliseconds; voxel, 2.5 x 5.0 x 10 mm(3)), rtMRSep (T-res = 48.8 milliseconds; voxel, 1.9 x 3.1 x 10 mm(3)), and rtHRSep ((Tres) = 48.3 milliseconds; voxel, 1.6 x 2.6 x 10 mm(3)), were investigated on 20 volunteers using GRAPPA reconstruction with internal as well as separate reference scans. End-diastolic volume, end-systolic volume, ejection fraction, peak ejection rate, peak filling rate, and myocardial mass were evaluated for the left ventricle and compared with an electrocardiogram-triggered segmented readout cine protocol used as standard of reference. All studies were performed at 3 T. Results: Phantom and in vivo data demonstrate that the combination of GRAPPA reconstruction with a separate reference scan provides an optimal compromise of image quality as well as spatial and temporal resolution. Functional values (P values) for the standard of reference, rtLRInt, rtMRSep, and rtHRSep end-diastolic volume were 141 +/- 24 mL, 138 +/- 21 mL, 138 +/- 19 mL, and 128 +/- 33 mL, respectively (P = 0.7, 0.7, 0.4); end-systolic volume, 55 +/- 15 mL, 61 +/- 14 mL, 58 +/- 12 mL, and 55 +/- 20 mL, respectively (P = 0.23, 0.43, 0.62); ejection fraction, 61% +/- 5%, 57% +/- 5%, 58% +/- 4%, and 56% +/- 8%, respectively (P = 0.01, 0.11, 0.06); peak ejection rate, 481 +/- 73 mL/s, 425 +/- 62 mL/s, 434 +/- 67 mL/s, and 381 +/- 86 mL/s, respectively (P = 0.03, 0.04, 0.01); peak filling rate, 555 +/- 80 mL/s, 480 +/- 70 mL/s, 500 +/- 70 mL/s, and 438 +/- 108 mL/s, respectively (P = 0.007, 0.05, 0.004); and myocardial mass, 137 +/- 26 g, 141 T 25 g, 141 +/- 23 g, and 130 +/- 31 g, respectively (P = 0.62, 0.54, 0.99). Conclusions: Using a separate reference scan and high acceleration factors up to R = 6, single-shot real-time cardiac imaging offers adequate temporal and spatial resolution for accurate assessment of global left ventricular function in free breathing with short examination times

Free Breathing Real-Time Cardiac Cine Imaging With Improved Spatial Resolution at 3 T

Objectives: The aim of this study was to evaluate free-breathing single-shot real-time cine imaging for functional cardiac imaging at 3 +/- with increased spatial resolution. Special emphasis of this study was placed on the influence of parallel imaging techniques. Materials and Methods: Gradient echo phantom images were acquired with GRAPPA and modified SENSE reconstruction using both integrated and separate reference scans as well as TGRAPPA and TSENSE. In vivo measurements were performed for GRAPPA reconstruction with an integrated and a separate reference scan, as well as TGRAPPA using balanced steady-state free precession protocols. Three clinical protocols, rtLRInt (T-res = 51.3 milliseconds; voxel, 2.5 x 5.0 x 10 mm(3)), rtMRSep (T-res = 48.8 milliseconds; voxel, 1.9 x 3.1 x 10 mm(3)), and rtHRSep ((Tres) = 48.3 milliseconds; voxel, 1.6 x 2.6 x 10 mm(3)), were investigated on 20 volunteers using GRAPPA reconstruction with internal as well as separate reference scans. End-diastolic volume, end-systolic volume, ejection fraction, peak ejection rate, peak filling rate, and myocardial mass were evaluated for the left ventricle and compared with an electrocardiogram-triggered segmented readout cine protocol used as standard of reference. All studies were performed at 3 T. Results: Phantom and in vivo data demonstrate that the combination of GRAPPA reconstruction with a separate reference scan provides an optimal compromise of image quality as well as spatial and temporal resolution. Functional values (P values) for the standard of reference, rtLRInt, rtMRSep, and rtHRSep end-diastolic volume were 141 +/- 24 mL, 138 +/- 21 mL, 138 +/- 19 mL, and 128 +/- 33 mL, respectively (P = 0.7, 0.7, 0.4); end-systolic volume, 55 +/- 15 mL, 61 +/- 14 mL, 58 +/- 12 mL, and 55 +/- 20 mL, respectively (P = 0.23, 0.43, 0.62); ejection fraction, 61% +/- 5%, 57% +/- 5%, 58% +/- 4%, and 56% +/- 8%, respectively (P = 0.01, 0.11, 0.06); peak ejection rate, 481 +/- 73 mL/s, 425 +/- 62 mL/s, 434 +/- 67 mL/s, and 381 +/- 86 mL/s, respectively (P = 0.03, 0.04, 0.01); peak filling rate, 555 +/- 80 mL/s, 480 +/- 70 mL/s, 500 +/- 70 mL/s, and 438 +/- 108 mL/s, respectively (P = 0.007, 0.05, 0.004); and myocardial mass, 137 +/- 26 g, 141 T 25 g, 141 +/- 23 g, and 130 +/- 31 g, respectively (P = 0.62, 0.54, 0.99). Conclusions: Using a separate reference scan and high acceleration factors up to R = 6, single-shot real-time cardiac imaging offers adequate temporal and spatial resolution for accurate assessment of global left ventricular function in free breathing with short examination times

Erratum:Randomized double-blind placebo-controlled trial of perhexiline in heart failure with preserved ejection fraction syndrome (Future Cardiology (2014) 10:6 (693-698))

Following publication of the Clinical Trial Protocol by Satnam Singh, Roger Beadle, Donnie Cameron, Amelia Rudd, Maggie Bruce, Baljit Jagpal, Konstantin Schwarz, Gemma Brindley, Fergus McKiddie, Chim Lang, Dana Dawson and Michael Frenneaux, titled ‘Randomized double-blind placebo-controlled trial of perhexiline in heart failure with preserved ejection fraction syndrome’, which appeared in the December 2014 issue of Future Cardiology (Future Oncol. 10[6], 693–698 [2014]), it has been brought to our attention that the author names were presented incorrectly as:Satnam Singh, Roger Beadle, Donnie Cameron, Amelia Rudd, Maggie Bruce, Baljit Jagpal, Konstantin Schwarz, Gemma Brindley, Fergus Mckiddie, Peter Nightingale, Chim Lang, Dana Dawson and Michael Frenneaux.The correct presentation should be:Satnam Singh, Roger Beadle, Donnie Cameron, Amelia Rudd, Maggie Bruce, Baljit Jagpal, Konstantin Schwarz, Gemma Brindley, Fergus Mckiddie, Chim Lang, Dana Dawson and Michael Frenneaux.The authors and editors of Future Cardiology would like to sincerely apologize for any inconvenience or confusion this may have caused our readers.<br/

Alloys for hydrogen storage in nickel/hydrogen and nickel/metal hydride batteries

Since 1990, there has been an ongoing collaboration among the authors in the three laboratories to (1) prepare alloys of the AB(sub 5) and AB(sub 2) types, using arc-melting/annealing and mechanical alloying/annealing techniques; (2) examine their physico-chemical characteristics (morphology, composition); (3) determine the hydrogen absorption/desorption behavior (pressure-composition isotherms as a function of temperature); and (4) evaluate their performance characteristics as hydride electrodes (charge/discharge, capacity retention, cycle life, high rate capability). The work carried out on representative AB(sub 5) and AB(sub 2) type modified alloys (by partial substitution or with small additives of other elements) is presented. The purpose of the modification was to optimize the thermodynamics and kinetics of the hydriding/dehydriding reactions and enhance the stabilities of the alloys for the desired battery applications. The results of our collaboration, to date, demonstrate that (1) alloys prepared by arc melting/annealing and mechanical alloying/annealing techniques exhibit similar morphology, composition and hydriding/dehydriding characteristics; (2) alloys with the appropriate small amounts of substituent or additive elements: (1) retain the single phase structure, (2) improve the hydriding/dehydriding reactions for the battery applications, and (3) enhance the stability in the battery environment; and (3) the AB(sub 2) type alloys exhibit higher energy densities than the AB(sub 5) type alloys but the state-of-the-art, commercialized batteries are predominantly manufactured using Ab(sub 5) type alloys

CT stress perfusion imaging for detection of haemodynamically relevant coronary stenosis as defined by FFR

Objectives: To evaluate the diagnostic accuracy (DA) of CT-myocardial perfusion imaging (CT-MPI) and a combined approach with CT angiography (CTA) for the detection of haemodynamically relevant coronary stenoses in patients with both suspected and known coronary artery disease. Design: Prospective, non-randomised, diagnostic study. Setting: Academic hospital-based study. Patients: 65 patients (42 men age 70.4 +/- 9) with typical or atypical chest pain. Interventions: CTA and CT-MPI with adenosine stress using a fast dual-source CT system. At subsequent invasive angiography, FFR measurement was performed in coronary arteries to define haemodynamic relevance of stenosis. Main outcome measures: We tried to correlate haemodynamically relevant stenosis (FFR <0.80) to a reduced myocardial blood flow (MBF) as assessed by CT-MPI and determined the DA of CT-MPI for the detection of haemodynamically relevant stenosis. Results: Sensitivity and negative predictive value (NPV) of CTA alone were very high (100% respectively) for ruling out haemodynamically significant stenoses, specificity, Positive predictive value (PPV) and DA were low (43.8, 67.3 and 72%, respectively). CT-MPI showed a significant increase in specificity, PPV and DA for the detection of haemodynamically relevant stenoses (65.6, 74.4 and 81.5%, respectively) with persisting high sensitivity and NPV for ruling out haemodynamically relevant stenoses (97% and 95.5% respectively). The combination of CTA and CT-MPI showed no further increase in detection of haemodynamically significant stenosis compared with CT-MPI alone. Conclusions: Our data suggest that CT-MPI permits the detection of haemodynamically relevant coronary artery stenoses with a moderate DA. CT may, therefore, allow the simultaneous assessment of both coronary morphology and function