Learning by Investing: Evidence from Venture Capital

To understand the investment behavior of venture capital (VC) investors, this paper estimates a dynamic model of learning. Behavior reflecting both learning from past investments (exploitation) and anticipated future learning (exploration) are found to be prevalent, and the model's additional predictions about success rates and investment speeds are confirmed empirically. Learning is important, since it can create informational frictions, and it has potential implications for VCs' investments and organizations. VCs are found to internalize the value of learning, and this may help promote exploration beyond the levels sustained in standard capital markets, which is socially valuable.Venture capital; Learning; Multi-armed bandit model

Multiple Andreev reflections in diffusive SNS structures

We report new measurements on sup-gap energy structure originating from multiple Andreev reflections in mesoscopic SNS junctions. The junctions were fabricated in a planar geometry with high transparency superconducting contacts of Al deposited on highly diffusive and surface d-doped n++-GaAs. For samples with a normal GaAs region of active length 0.3um the Josephson effect with a maximal supercurrent Ic=3mA at T=237mK was observed. The sub-gap structure was observed as a series of local minima in the differential resistance at dc bias voltages V=2D/ne with n=1,2,4 i.e. only the even sub-gap positions. While at V=2D/e (n=1) only one dip is observed, the n=2, and the n=4 sub-gap structures each consists of two separate dips in the differential resistance. The mutual spacing of these two dips is independent of temperature, and the mutual spacing of the n=4 dips is half of the spacing of the n=2 dips. The voltage bias positions of the sub-gap differential resistance minima coincide with the maxima in the oscillation amplitude when a magnetic field is applied in an interferometer configuration, where one of the superconducting electrodes has been replaced by a flux sensitive open loop.Comment: 20 pages, 7 figure

BIOMECHANICAL REFLECTIONS ON TEACHING FAST MOTOR SKILLS

Learning to perform a novel movement is believed to require the formation of an internal motor memory model in the central nervous system. This internal model is subsequently used to control the movement, i.e. coordinate muscle generated moments with nonmuscle generated moments in order to execute the intended movement. A substantial part of the non-muscle generated moments acting on each segment in a fast unloaded movement arises due to movement of adjacent segments. If a complex novel movement is taught either in slow motion or by splitting it into partial movements, these intersegmental moments will not be present, and hence not accounted for in the internal motor memory model. It is suggested that coaches take this into account when methods for teaching fast motor skills are considered

Imposing high-symmetry and tuneable geometry on lanthanide centres with chelating Pt and Pd metalloligands

Exploitation of HSAB preferences allows for high-yield, one-pot syntheses of lanthanide complexes chelated by two Pd or Pt metalloligands, [MII(SAc)4]2− (SAc− = thioacetate, M = Pd, Pt). The resulting complexes with 8 oxygen donors surrounding the lanthanides can be isolated in crystallographically tetragonal environments as either [NEt4]+ (space group: P4/mcc) or [PPh4]+ (space group: P4/n) salts. In the case of M = Pt, the complete series of lanthanide complexes has been structurally characterized as the [NEt4]+ salts (except for Ln = Pm), while the [PPh4]+ salts have been structurally characterized for Ln = Gd–Er, Y. For M = Pd, selected lanthanide complexes have been structurally characterized as both salts. The only significant structural difference between salts of the two counter ions is the resulting twist angle connecting tetragonal prismatic and tetragonal anti-prismatic configurations, with the [PPh4]+ salts approaching ideal D4d symmetry very closely (φ = 44.52–44.61°) while the [NEt4]+ salts exhibit intermediate twist angles in the interval φ = 17.28–27.41°, the twist increasing as the complete 4f series is traversed. Static magnetic properties for the latter half of the lanthanide series are found to agree well in the high temperature limit with the expected Curie behavior. Perpendicular and parallel mode EPR spectroscopy on randomly oriented powder samples and single crystals of the Gd complexes with respectively Pd- and Pt-based metalloligands demonstrate the nature of the platinum metal to strongly affect the spectra. Consistent parametrization of all of the EPR spectra reveals the main difference to stem from a large difference in the magnitude of the leading axial term, B02, this being almost four times larger for the Pt-based complexes as compared to the Pd analogues, indicating a direct Pt(5dz2)–Ln interaction and an arguable coordination number of 10 rather than 8. The parametrization of the EPR spectra also confirms that off-diagonal operators are associated with non-zero parameters for the [NEt4]+ salts, while only contributing minimally for the [PPh4]+ salts in which lanthanide coordination approximates D4d point group symmetry closely.LHD acknowledges support from NSF-CCT EMT 08-517. (08-517 - NSF-CCT EMT

Sorafenib in Advanced Hepatocellular Carcinoma: A Nationwide Retrospective Study of Efficacy and Tolerability

Background. Advanced HCC is a clinical challenge with limited treatment options. The multikinase inhibitor sorafenib is the first and only agent showing a survival benefit in these patients. In this study we evaluate the efficacy and tolerability of sorafenib in an unselected patient population. Furthermore we explore the role of alpha-fetoprotein (αFP) as a potential biomarker for treatment efficacy and correlation to survival. Methods. Seventy-six patients with advanced HCC, not eligible for locoregional therapy, treated with sorafenib between 2007 and 2009 were included. Followup was until 2011. Results. Patients in PS 0-1 had a median overall survival (mOS) of 6.2 months, compared to 1.8 months in patients with poorer PS (P=0.005). Child-Pugh A patients had a mOS of 6.6 months versus 3.6 months among patients in Child-Pugh B or C (P=0.0001). Serum αFP ≥ 200 at baseline was prognostic for a shorter survival. All patients with radiologically verified tumor response and baseline αFP ≥ 200 experienced a significant decline in αFP within the first four weeks of treatment. Conclusion. The survival of patients with advanced HCC treated with sorafenib is dependent on performance status and liver function. Treatment of patients with compromised liver function and poor performance status cannot be recommended. The correlation between αFP and objective tumor response warrants further investigation

Which CEO Characteristics and Abilities Matter?

We study the characteristics and abilities of CEO candidates for companies involved in buyout (LBO) and venture capital (VC) transactions and relate them to hiring decisions, investment decisions, and company performance. Candidates are assessed on more than thirty individual abilities. The abilities are highly correlated; a factor analysis suggests there are two primary factors with intuitive characterizations -- one for general ability and one that contrasts team-related, interpersonal skills with execution skills. Both LBO and VC firms are more likely to hire and invest in CEOs with greater general abilities, both execution- and team-related. Success, however, is more strongly related to execution skills than to team-related skills. Success is, at best, only marginally related to incumbency, holding observable talent and ability constant.

Emergence of NDM-1-producing Enterobacteriaceae in China

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