Partner Uncertainty and the Dynamic Boundary of the Firm

We develop a new theory of the dynamic boundary of the firm where asset owners may want to change partners ex-post. The model identifies a fundamental trade-off between (i) a “displacement externality” under non-integration, where a partner leaves a relationship even though his benefit is worth less than the loss to the displaced partner, and (ii) a “retention externality” under integration, where a partner inefficiently retains the other. With more asset specificity, displacement externalities matter more and retention externalities less, so that integration becomes more attractive. Our model also shows that wealthy partners would want to commit to ex-post wealth constraints

Friends or foes? The interrelationship between angel and venture capital markets

This paper develops a theory of how angel and venture capital markets interact. Entrepreneurs first receive angel then venture capital funding. The two investor types are ‘friends’ in that they rely upon each other׳s investments. However, they are also ‘foes,’ because at the later stage the venture capitalists no longer need the angels. Using a costly search model we derive the equilibrium deal flows across the two markets, endogenously deriving market sizes, competitive structures, valuation levels, and exit rates. We also examine the role of legal protection for angel investments

Contracting Among Founders

This paper develops a theory of contracting among founders of a new firm. It asks at whatstage founders agree to commit to each other, how they structure optimal founder contracts, and how this affects team formation, ownership, incentives, and performance. The paper derives a trade-off between upfront contracting, which can result in teams with ineffective founders, versus delayed contracting, which can enable some founders to appropriate ideas and start their own firms. Delayed contracting becomes more attractive when there are significant doubts about the skills of founders. Contingent contracts with vesting of shares may be used to mitigate inefficiencies in the team formation process. Interestingly we show that outside investors cannot easily undo ex-post inefficient founder agreements. We also show that laws that provide protection to implied partnerships may have the unintended effect of encouraging more formal contracting

Partner Uncertainty and the Dynamic Boundary of the Firm

We develop a new theory of the dynamic boundary of the firm where asset owners may want to change partners ex-post. The model identifies a fundamental trade-off between (i) a “displacement externality” under non-integration, where a partner leaves a relationship even though his benefit is worth less than the loss to the displaced partner, and (ii) a “retention externality” under integration, where a partner inefficiently retains the other. With more asset specificity, displacement externalities matter more and retention externalities less, so that integration becomes more attractive. Our model also shows that wealthy partners would want to commit to ex-post wealth constraints

Space‐time PU‐DWR error control and adaptivity for the heat equation

In this work, space-time goal-oriented a posteriori error estimation using a partition-of-unity localization is applied to the linear heat equation. The algorithmic developments are substantiated with a numerical example

Numerical modeling and open-source implementation of variational partition-of-unity localizations of space-time dual-weighted residual estimators for parabolic problems

In this work, we consider space-time goal-oriented a posteriori error estimation for parabolic problems. Temporal and spatial discretizations are based on Galerkin finite elements of continuous and discontinuous type. The main objectives are the development and analysis of space-time estimators, in which the localization is based on a weak form employing a partition-of-unity. The resulting error indicators are used for temporal and spatial adaptivity. Our developments are substantiated with several numerical examples.Comment: Changes in v2: - Updated the title - Reworked space-time function spaces - Added cG(1) in time partition-of-unity - Added links to the now published codes used for this work - Added further reference

Die M�rkte f�r Fleisch und Fleischprodukte

Agricultural and Food Policy, Agribusiness, Demand and Price Analysis, Livestock Production/Industries, Food Consumption/Nutrition/Food Safety, International Relations/Trade,

Neural Correlates of Contrast Detection at Threshold

AbstractHuman psychophysical studies have demonstrated that, for stimuli near the threshold of visibility, detection of motion in one direction is unaffected by the superimposition of motion in the opposite direction. To investigate the neural basis for this perceptual phenomenon, we recorded from directionally selective neurons in macaque visual area MT (middle temporal visual area). Contrast thresholds obtained for single gratings moving in a neuron's preferred direction were compared with those obtained for motion presented simultaneously in the neuron's preferred and anti–preferred directions. A simple model based on probability summation between neurons tuned to opposite directions could sufficiently account for contrast thresholds revealed psychophysically, suggesting that area MT is likely to provide the neural basis for contrast detection of stimuli modulated in time

Angle dependent magnetization reversal of thin film magnetic recording media

The results of angular measurements of the remanent switching fields for granular longitudinal and perpendicular magnetic recording media are presented and compared to idealized models of magnetic switching. Co alloy longitudinal and perpendicular recording media are found primarily to have a Stoner-Wohlfarth switching character at vibrating sample magnetometer time scales. Since the Stoner-Wohlfarth model does not consider the effects of thermal activation, the angular dependence of the time independent switching field H-swro(theta) was determined from a Sharrock analysis. This approach shows a closer agreement between experimental data and model. For the case of a representative high density longitudinal recording medium, we additionally investigate the switching field distribution

Measurement of the air-to-fuel ratio inside a passive pre-chamber of a fired spark-ignition engine

This paper investigates the local air-to-fuel ratio measurement within the pre-chamber of a spark-ignition engine by determining the absorption of light from hydrocarbons using an infrared sensor. The measurement was performed during fired and motored engine operation points and compared to the more common exhaust lambda measurements. The experiment provided data to compare the mixture preparation in a hot and cold environment of pre-chamber and main combustion chamber. The experiment also gives an indication regarding the possible use of a pre-chamber sensor in a motored engine at higher boost pressures and fuel mass flows, operation points that would overheat the sensor in a fired engine. The work also includes the analysis of the fuel delivery into the pre-chamber of a direct and indirect injection engine. Furthermore, pressure and temperature measurement within the pre-chamber provides information about the critical sensor environment and helps to understand the gas exchange between the two volumes