Exact Strongly Coupled Fixed Point in gφ4g\varphi^4 Theory

We show explicitly how a strongly coupled fixed point can be constructed in scalar $g\varphi^4$ theory from the solutions to a non-linear eigenvalue problem. The fixed point exists only for $d< 4$, is unstable and characterized by $\nu=2/d$ (correlation length exponent), $\eta=1/2-d/8$ (anomalous dimension). For $d=2$, these exponents reproduce to those of the Ising model which can be understood from the codimension of the critical point. At this fixed point, $\varphi^{2i}$ terms with $i>2$ are all irrelevant. The testable prediction of this fixed point is that the specific heat exponent vanishes. 2d critical Mott systems are well described by this new fixed point.Comment: revised version of previous paper with a proof of the irrelevance of \varphi^6 and higher terms at fixed poin

Self-Selection and Tests for Bias and Risk in Mortgage Lending: Can You Price the Mortgage If You Don't Know the Process?

There is increasing interest in understanding the determinants of mortgage rejection by lenders and default by borrowers. Although many researchers have proposed simple single-equation models of rejection and default, we argue that far more complex econometric specifications are needed. This paper focuses attention on problems of sample selection in the process creating a sample of applicants for conventional mortgages. We illustrate that corrections for sample selection bias may have a substantial effect on estimation results and hence should not be ignored in studies of mortgage rejection or default.

Carbohydrate gel ingestion significantly improves the intermittent endurance capacity, but not sprint performance, of adolescent team games players during a simulated team games protocol

The aim of this study was to investigate the influence of ingesting a carbohydrate (CHO) gel on the intermittent endurance capacity and sprint performance of adolescent team games players. Eleven participants [mean age 13.5 ± 0.7 years, height 1.72 ± 0.08 m, body mass (BM) 62.1 ± 9.4 kg] performed two trials separated by 3–7 days. In each trial, they completed four 15 min periods of part A of the Loughborough Intermittent Shuttle Test (LIST), followed by an intermittent run to exhaustion (part B). In the 5 min pre-exercise, participants consumed 0.818 mL kg−1 BM of a CHO or a non-CHO placebo gel, and a further 0.327 mL kg−1 BM every 15 min during part A of the LIST (38.0 ± 5.5 g CHO h−1 in the CHO trial). Intermittent endurance capacity was increased by 21.1% during part B when the CHO gel was ingested (4.6 ± 2.0 vs. 3.8 ± 2.4 min, P < 0.05, r = 0.67), with distance covered in part B significantly greater in the CHO trial (787 ± 319 vs. 669 ± 424 m, P < 0.05, r = 0.57). Gel ingestion did not significantly influence mean 15 m sprint time (P = 0.34), peak sprint time (P = 0.81), or heart rate (P = 0.66). Ingestion of a CHO gel significantly increases the intermittent endurance capacity of adolescent team games players during a simulated team games protocol

Hook-billed Kite, Chondrohierax uncinatus, southbound autumn migration in Belize and Mexico

The Hook-billed Kite (Chondrohierax uncinatus) is a specialized Neotropical raptor with a wide distribution that has received little research attention. The species is considered non-migratory across most of its distribution, but there are scattered records of Hook-billed Kite migration. The present research describes, for the first time, the largest southbound autumn migration of Hook-billed Kite in Belize and Mexico and evaluates the effects of environmental conditions on this phenomenon. Eight years of count data were collected in Belize and 25 years in Mexico. During a total of 3093.1 count hr from 2013-2020 in Belize, 39928 Hook-billed Kites were counted on their southbound autumn migration with a mean (±SE) annual count of 4991 ± 1083 kites/yr. In comparison, during a total of 42531 count hr from 1995-2019 at two count sites in Mexico, 3870 Hook-billed Kites were counted. The mean 95% seasonal passage window of Hook-billed Kites in Belize was 44.9 ± 2.5 d (n= 8) from 26 October to 9 December compared to 13 September to 11 November in Mexico. Precipitation on the breeding grounds had no influence on the timing or magnitude of the kite migration through Belize, whereas in Mexico, migration time occurred later as precipitation north of the count site increased. The present research provides critical ecological information, which can aid in identifying potential threats, conservation needs, and population status for Hook-billed Kites and other neotropical raptors