Two-loop perturbative corrections to the constrained effective potential in thermal QCD

In this paper, we compute the constrained QCD effective potential up to two-loop order with finite quark mass and chemical potential. We present the explicit calculations by using the double line notation and analytical expressions for massless quarks are obtained in terms of the Bernoulli polynomials or Polyakov loops. Our results explicitly show that the constrained QCD effective potential is independent on the gauge fixing parameter. In addition, as compared to the massless case, the constrained QCD effective potential with massive quarks develops a completely new term which is only absent when the background field vanishes. Furthermore, we discuss the relation between the one- and two-loop constrained effective potential. The surprisingly simple proportionality that exists in the pure gauge theories, however, is in general no longer true when fermions are taken into account. On the other hand, for high baryon density $\mu_B$ and low temperature $T$, in the massless limit, we do also find a similar proportionality between the one- and two-loop fermionic contributions in the constrained effective potential up to ${\cal O}(T/\mu_B)$.Comment: 36 pages, 5 figs, final version in JHE

Getting tired of your friends: the dynamics of venture capital relationships

We empirically examine how venture capitalists adjust coinvestor relationships over time. We identify a fundamental trade-off where the benefits of familiarity are weighed against the opportunity costs of coinvesting with other syndication partners. Using US data, we find that venture capitalists dynamically adjust their relationship intensities by gradually disengaging from overly deep relationships. More centrally networked investors are more cautious with disengaging. In hot investment markets investors disengage more readily from existing relationships, but new relationships forged in hot market are less enduring. Perhaps surprisingly, we find a negative relationship between deeper prior relationships and investment performance

TRA-940: ASSESSING CURRENT AND FUTURE MACKENZIE RIVER FREIGHT VOLUMES IN THE CONTEXT OF CLIMATE CHANGE IMPACTS

The Mackenzie River is a major freight transportation route that connects many remote communities in the Northwest Territories and parts of Nunavut to southern Canada’s transportation network. The river is only navigable during the summer months, from mid-June until sometime in late-September to mid-October, when it is clear of ice. However, the water conditions of the river have changed significantly in recent years. Although water levels always decrease as the delivery season moves into fall, these reductions have been occurring much faster, in turn reducing barge loading capacities as well as operational speeds. In addition, based on simulations of ice breakup and water volumes in the Mackenzie River basin, the sailing season opening dates are anticipated to shift earlier in the future. In the end, the main impact of climate change on river transport is not definitive events but rather, increased variability in events. This research aims to account for those abovementioned climate changes in the freight volume scheduling process, and conducts a numerical analysis based on the projections of future water conditions from climate simulation models as well as predicted freight volumes from time-series analysis and forecast models. The results of the numerical analysis can help local government and waterway transportation companies to better understand how freight scheduling strategies could account for climate changes that affect regional waterway transportation and, hence, optimize their operational schedules to take advantage of good water conditions while reducing financial cost

Real-time hard-thermal-loop gluon self-energy in a semiquark-gluon plasma

In the real time formalism of the finite-temperature field theory, we compute the one-loop gluon self-energy in a semi-quark-gluon plasma (QGP) where a background filed ${\cal Q}$ has been introduced for the vector potential, leading to a non-trivial expectation value for the Polyakov loop in the deconfined phase. Explicit results of the gluon self-energies up to the next-to-leading order in the hard-thermal-loop approximation are obtained. We find that for the retarded/advanced gluon self-energy, the corresponding contributions at next-to-leading order are formally analogous to the well-known result at ${\cal Q}=0$ where the background field modification on the Debye mass is entirely encoded in the second Bernoulli polynomials. The same feature is shared by the leading order contributions in the symmetric gluon self-energy where the background field modification becomes more complicated, including both trigonometric functions and the Bernoulli polynomials. These contributions are non-vanishing and reproduce the correct limit as ${\cal Q} \rightarrow 0$. In addition, the leading order contributions to the retarded/advanced gluon self-energy and the next-to-leading order contributions to the symmetric gluon self-energy are completely new as they only survive at ${\cal Q}\neq0$. Given the above results, we explicitly verify that the Kubo-Martin-Schwinger condition can be satisfied in a semi-QGP with non-zero background field.Comment: final version published in PR

Standing Out from the Crowd: The Real Effects of Outliers

We study the impact of outlier opinions – extreme views voiced by individuals – in financial markets. Using analyst forecasts as a laboratory, we show that market participants respond to the arrival of extremely optimistic forecasts, instead of ignoring them as noise. An outlier forecast subsequently moves group consensus and begets more extreme forecasts by peers. Outlier forecasts also generate stronger market reactions from investors, more media coverage, and more conservative management guidance. Further analyses reveal that issuing outlier forecasts increases an analyst’s chance to cover more important clients of his employer. Outlier forecasts are also more likely to take place when an analyst’s reputation cost is lower and information uncertainty is high. These findings suggest that the propensity for expressing extreme views is situational and that personal incentives are the likely cause at play

The Effects of Government-Sponsored Venture Capital: International Evidence

This paper examines the impact of government-sponsored venture capitalists (GVCs) on the success of enterprises. Using international enterprise-level data, we identify a surprising non-monotonicity in the effect of GVC on the likelihood of exit via initial public offerings (IPOs) or third party acquisitions. Enterprises that receive funding from both private venture capitalists (PVCs) and GVCs outperform benchmark enterprises financed purely by private venture capitalists if only a moderate fraction of funding comes from GVCs. However, enterprises underperform if a large fraction of funding comes from GVCs. Instrumental variable regressions suggest that endogeneity in the form of unobservable selection effects cannot account for these effects of GVC financing. The underperformance result appears to be largely driven by investments made in times when private venture capital is abundant. The outperformance result applies only to venture capital firms that are supported but not owned outright by governments.

Characteristics of Pollen from Transgenic Lines of Apple Carrying the Exogenous CpTI Gene

AbstractIt is fundamental for gene transformation and ecosystem hazard evaluation to study the pollen characteristics of transgenic plants. In this research, the characteristics of pollen from 7- or 8-year-old transgenic apple plants carrying an exogenous CpTI gene were analyzed. The results showed that there was no significant difference in terms of size, morphology, or exine ornamentation between the pollen of the transgenic plants and the non-transgenic control. However, the transgenic plants had more abnormal pollen grains. Of the 13 transgenic lines tested, 12 had a significantly lower amount of pollen and six exhibited a significantly lower germination rate when cultured in vitro. The pollen viability of three transgenic lines was determined, with two showing significantly lower viability than the control. The transgenic Gala apple pollen grains germinated normally via controlled pollination on Fuji apple stigmas. However, the pollen tubes extended relatively slowly during the middle and late development stages, and another 8h were needed to reach the ovules compared with the control. The gibberellic acid concentration in transgenic Gala apple flowers was lower than in the non-transgenic control during all development stages tested. The abscisic acid concentration in the transgenic flowers was lower during the pink stage, and higher during the ball and fully open stages. Microscopic observation of the anther structure showed no difference. The tapetum of the pollen sac wall in transgenic plants decomposed late and affected pollen grain development, which could be one of the reasons for the lower number of pollen grains and poor viability in the transgenic plants