Access to financing, rents, and organization of the firm

This paper provides a theory for the choice of an organizational structure by the headquarters of a unitary structure concerned about overload. The headquarters can avoid overload by delegating operational decisions to divisions, i.e., moving the firm to a multidivisional structure. We show that, under moral hazard, these divisions receive rents for incentive purposes, and that the multidivisional structure is able to invest more. Thus, there is a trade-off between increasing investment and paying rents. We also show that this trade-off applies to situations where firms consider engaging in acquisitions and joint ventures, or where entrepreneurs consider resorting to venture capitalists.Unitary-form; Multidivisional-form; Agency rents; Credit rationing

Reputation Capital, Financial Capital, and Transition to Entrepreneurship.

We provide a theory for career choices of employees willing to become entrepreneurs and facing credit constraints. We show that they need a sufficient mix of reputation and financial capital. We consider their choice to work for transparent or opaque firms. Transparent firms disclose more information about their employees. It has two consequences. First, it eases the updating of the employees'reputation, which is positive for those with a bad initial reputation and negative otherwise. Second, it fosters incentives to exert effort, which increases the wage, and thus, the financial capital available for setting a business venture. Employees thus adopt strategies that depend on their initial reputation. We also show that employees whose alternative is to choose between transparent and opaque projects to work on once employed make transparency choices that differ from employees who choose firms to work for. The former are less likely to become entrepreneurs than the latter.Transition; Financial Capital; Career Concerns; Entrepreneurship; Reputation;

When Promotions Induce Good Managers to Be Lazy

This paper shows that when being perceived as a good manager is a necessary condition to be promoted, a priori talented managers may undertake excessively risky projects. Indeed, such a choice renders more difficult the updating of beliefs process regarding their actual types. In turn, good managers are induced to lower the level of effort they perform since the extent to which effort impacts the perception the market has about their talent is lessened. This adversely impacts the firms' profits. Hence, career concerns do not discipline good managers in our context. However, we show how employers can limit managerial slack by increasing monitoringPromotions, career concerns, choice of risk, monitoring by corporate owners

Professional Reputation, Cash, and Transition to Entrepreneurial Activity.

Cash; professional reputation; entrepreneurship;

Professional Reputation, Cash, and Transition to Entrepreneurial Activity.

We analyze the role of professional reputation in the transition to entrepreneurial activity when credit is rationed. We study an employee's willingness to allow the market to learn information about talent by choosing more or less informative projects. This choice impacts the employee's incentives to exert effort, which determines the wage, and in turn the cash to be invested in the business venture. We show that reputation and cash are substitutes in overcoming credit rationing. However, maintaining a good reputation conflicts with accumulating cash. Hence, employees adopt a different strategy depending on their initial reputation. Besides, starting a business venture early can in expectation be easier than waiting in order to build a reputation and accumulate cash.Corporate finance; Econométrie; Professional reputation; entrepreneurship;

Optimal Linear Signal: An Unsupervised Machine Learning Framework to Optimize PnL with Linear Signals

This study presents an unsupervised machine learning approach for optimizing Profit and Loss (PnL) in quantitative finance. Our algorithm, akin to an unsupervised variant of linear regression, maximizes the Sharpe Ratio of PnL generated from signals constructed linearly from exogenous variables. The methodology employs a linear relationship between exogenous variables and the trading signal, with the objective of maximizing the Sharpe Ratio through parameter optimization. Empirical application on an ETF representing U.S. Treasury bonds demonstrates the model's effectiveness, supported by regularization techniques to mitigate overfitting. The study concludes with potential avenues for further development, including generalized time steps and enhanced corrective terms.Comment: The code of the model and the empiric strategy are available on my GitHub: Cnernc/OptimalLinearSigna

Mathematical modelling techniques for the computer simulation of vehicle dynamic performance and response

Abstract available: [p. 2

Spin and recombination dynamics of excitons and free electrons in p-type GaAs : effect of carrier density

Carrier and spin recombination are investigated in p-type GaAs of acceptor concentration NA = 1.5 x 10^(17) cm^(-3) using time-resolved photoluminescence spectroscopy at 15 K. At low pho- tocarrier concentration, acceptors are mostly neutral and photoelectrons can either recombine with holes bound to acceptors (e-A0 line) or form excitons which are mostly trapped on neutral acceptors forming the (A0X) complex. It is found that the spin lifetime is shorter for electrons that recombine through the e-A0 transition due to spin relaxation generated by the exchange scattering of free electrons with either trapped or free holes, whereas spin flip processes are less likely to occur once the electron forms with a free hole an exciton bound to a neutral acceptor. An increase of exci- tation power induces a cross-over to a regime where the bimolecular band-to-band (b-b) emission becomes more favorable due to screening of the electron-hole Coulomb interaction and ionization of excitonic complexes and free excitons. Then, the formation of excitons is no longer possible, the carrier recombination lifetime increases and the spin lifetime is found to decrease dramatically with concentration due to fast spin relaxation with free photoholes. In this high density regime, both the electrons that recombine through the e-A0 transition and through the b-b transition have the same spin relaxation time.Comment: 4 pages, 5 figure

Observation of Chiral character deep in the topological insulating regime in Bi1−x_{1-x}Sbx_x

Bi$_{1-x}$Sb$_x$ is a topological insulator (TI) for $x \approx 0.03$--$0.20$. Close to the Topological phase transition at $x = 0.03$, a magnetic field induced Weyl semi-metal (WSM) state is stabilized due to the splitting of the Dirac cone into two Weyl cones of opposite chirality. A signature of the Weyl state is the observation of a Chiral anomaly [negative longitudnal magnetoresistance (LMR)] and a violation of the Ohm's law (non-linear $I-V$). We report the unexpected discovery of a Chiral anomaly in the whole range ($x = 0.032, 0.072, 0.16$) of the TI state. This points to a field induced WSM state in an extended $x$ range and not just near the topological transition at $x = 0.03$. Surprisingly, the strongest Weyl phase is found at $x = 0.16$ with a non-saturating negative LMR much larger than observed for $x = 0.03$. The negative LMR vanishes rapidly with increasing angle between $B$ and $I$. Additionally, non-linear $I$--$V$ is found for $x = 0.16$ indicating a violation of Ohm's law. This unexpected observation of a strong Weyl state in the whole TI regime in Bi$_{1-x}$Sb$_x$ points to a gap in our understanding of the detailed electronic structure evolution in this alloy system.Comment: 5 Pages, 4 figure