Impacts of model calibration on high-latitude land-surface processes: PILPS 2(e) calibration/validation experiments

In the PILPS 2(e) experiment, the Snow Atmosphere Soil Transfer (SAST) land-surface scheme developed from the Biosphere-Atmosphere Transfer Scheme (BATS) showed difficulty in accurately simulating the patterns and quantities of runoff resulting from heavy snowmelt in the high-latitude Torne-Kalix River basin (shared by Sweden and Finland). This difficulty exposes the model deficiency in runoff formations. After representing subsurface runoff and calibrating the parameters, the accuracy of hydrograph prediction improved substantially. However, even with the accurate precipitation and runoff, the predicted soil moisture and its variation were highly "model-dependent". Knowledge obtained from the experiment is discussed. © 2003 Elsevier Science B.V. All rights reserved

Thermodynamics of lattice QCD with 2 flavours of colour-sextet quarks: A model of walking/conformal Technicolor

QCD with two flavours of massless colour-sextet quarks is considered as a model for conformal/walking Technicolor. If this theory possess an infrared fixed point, as indicated by 2-loop perturbation theory, it is a conformal(unparticle) field theory. If, on the other hand, a chiral condensate forms on the weak-coupling side of this would-be fixed point, the theory remains confining. The only difference between such a theory and regular QCD is that there is a range of momentum scales over which the coupling constant runs very slowly (walks). In this first analysis, we simulate the lattice version of QCD with two flavours of staggered quarks at finite temperatures on lattices of temporal extent $N_t=4$ and 6. The deconfinement and chiral-symmetry restoration couplings give us a measure of the scales associated with confinement and chiral-symmetry breaking. We find that, in contrast to what is seen with fundamental quarks, these transition couplings are very different. $\beta=6/g^2$ for each of these transitions increases significantly from $N_t=4$ and $N_t=6$ as expected for the finite temperature transitions of an asymptotically-free theory. This suggests a walking rather than a conformal behaviour, in contrast to what is observed with Wilson quarks. In contrast to what is found for fundamental quarks, the deconfined phase exhibits states in which the Polyakov loop is oriented in the directions of all three cube roots of unity. At very weak coupling the states with complex Polyakov loops undergo a transition to a state with a real, negative Polyakov loop.Comment: 21 pages, 9 figures, Revtex with postscript figures. One extra reference was added; text is unchanged. Corrected typographical erro

Nucleon Sigma Term and In-medium Quark Condensate in the Modified Quark-Meson Coupling Model

We evaluate the nucleon sigma term and in-medium quark condensate in the modified quark-meson coupling model which features a density-dependent bag constant. We obtain a nucleon sigma term consistent with its empirical value, which requires a significant reduction of the bag constant in the nuclear medium similar to those found in the previous works. The resulting in-medium quark condensate at low densities agrees well with the model independent linear order result. At higher densities, the magnitude of the in-medium quark condensate tends to increase, indicating no tendency toward chiral symmetry restoration.Comment: 9 pages, modified version to be publishe

Social Threat Framing on the Fundraising Performance: Evidence from Equity-based Crowdfunding Firms

In this study, we seek to investigate the impact of a firm’s social threat framing on its fundraising performance in equity-based crowdfunding. Crowdfunding ventures have growingly committed to social initiatives to attract investors. However, the success crucially depends on how much the investors value the prosocial cues presented in the proposal. Drawing on the perspective of threat framing, we argue that firms’ framing of social issues as a societal threat in their crowdfunding proposals promotes the fundraising performance. A social threat framing increases perceived importance of the firm’s business and sustainability initiatives in the eyes of investors by developing a sense of urgency and commitment towards the social issues. Using a sample of 229 U.S. equity crowdfunding firms from 2015 to 2021, we found a significant positive relationship between social threat framing and the fundraising performance. We also examined some conditional variables for such an effect, such as firm characteristics and the linguistic styles used in the crowdfunding proposals

The Impact of Social Threat Framing on Crowdfunding Performance: The Moderating Roles of Family Involvement and Linguistic Style

There has been increased use of social causes in crowdfunding proposals. Building on prior literature on issue framing in crowdfunding, we argue that framing of social threats, which integrates social framing and negative framing, can be particularly useful in attracting funding by creating a strong sense of urgency among investors. We find support for such a positive effect of social threat framing based on a sample of 217 U.S. equity crowdfunding firms from 2015 to 2021. Meanwhile, we find that social threat framing is more effective for family firms than nonfamily firms in improving crowdfunding performance, whereas local orientation presented in funding proposals does not show a significant effect. We also find that two styles of language - emotional expression and analytical thinking - present opposite moderation effects; the former strengthens the relationship, while the latter weakens it. The implications of the findings on crowdfunding success and effective communication are discussed

Thermodynamics of lattice QCD with 2 sextet quarks on N_t=8 lattices

We continue our lattice simulations of QCD with 2 flavours of colour-sextet quarks as a model for conformal or walking technicolor. A 2-loop perturbative calculation of the $\beta$-function which describes the evolution of this theory's running coupling constant predicts that it has a second zero at a finite coupling. This non-trivial zero would be an infrared stable fixed point, in which case the theory with massless quarks would be a conformal field theory. However, if the interaction between quarks and antiquarks becomes strong enough that a chiral condensate forms before this IR fixed point is reached, the theory is QCD-like with spontaneously broken chiral symmetry and confinement. However, the presence of the nearby IR fixed point means that there is a range of couplings for which the running coupling evolves very slowly, i.e. it 'walks'. We are simulating the lattice version of this theory with staggered quarks at finite temperature studying the changes in couplings at the deconfinement and chiral-symmetry restoring transitions as the temporal extent ($N_t$) of the lattice, measured in lattice units, is increased. Our earlier results on lattices with $N_t=4,6$ show both transitions move to weaker couplings as $N_t$ increases consistent with walking behaviour. In this paper we extend these calculations to $N_t=8$. Although both transition again move to weaker couplings the change in the coupling at the chiral transition from $N_t=6$ to $N_t=8$ is appreciably smaller than that from $N_t=4$ to $N_t=6$. This indicates that at $N_t=4,6$ we are seeing strong coupling effects and that we will need results from $N_t > 8$ to determine if the chiral-transition coupling approaches zero as $N_t \rightarrow \infty$, as needed for the theory to walk.Comment: 21 pages Latex(Revtex4) source with 4 postscript figures. v2: added 1 reference. V3: version accepted for publication, section 3 restructured and interpretation clarified. Section 4 future plans for zero temperature simulations clarifie