Language-Skill Complementarity: Returns to Immigrant Language Acquisition

We examine the effect of language acquisition on the growth of immigrants' earnings. We gathered data on recent Soviet immigrants to Israel that include retrospective questions on earnings and language ability on entry into their current job. Language acquisition is found to interact positively with occupation level. Immigrant programmers and computer technicians have a return to tenure about three percentage points higher than that of natives; improved Hebrew language skills account for between 2/3 and 3/4 of that differential wage growth. In contrast, construction workers and gas station attendants have no convergence of wages to those of natives and language acquisition has no discernible effect on their wages. For these less skilled workers the estimated return' to Hebrew proficiency in the cross-section is entirely due to ability bias. This finding may invite a reinterpretation of other studies on the returns to language acquisition for low wage immigrants.

Why Is an Elite Undergraduate Education Valuable? Evidence from Israel

In this paper we compare the labor market performance of Israeli students who graduated from one of the leading universities, Hebrew University (HU), with those who graduated from a professional undergraduate college, College of Management Academic Studies (COMAS). Our results support a model in which employers have good information about the quality of HU graduates and pay them according to their ability, but in which the market has relatively little information about COMAS graduates. Hence, high-skill COMAS graduates are initially treated as if they were the average COMAS graduate, who is weaker than a HU graduate, consequently earning less than UH graduates. However, over time the market differentiates among them so that after several years of experience, COMAS and HU graduates with similar entry scores have similar earnings. Our results are therefore consistent with the view that employers use education information to screen workers but that the market acquires information fairly rapidly.

Delayed chilling appears to counteract flowering advances of apricot in southern UK

Temperatures are rising across the globe, and the UK is no exception. Spring phenology of perennial fruit crops is to a large extent determined by temperature during effective chilling (endo-dormancy) and heat accumulation (eco-dormancy) periods. We used the apricot flowering records of the UK National Fruit Collections (NFC) to determine the influence of temperature trends over recent decades (1960 to 2014) on apricot (Prunus armeniaca L.) flowering time. Using Partial Least Squares (PLS) regression, we determined the respective periods for calculating chill and heat accumulation. Results suggested intervals between September 27th and February 26th and between December 31st and April 12th as the effective chilling and warming periods, respectively. Flowering time was correlated with temperature during both periods, with warming during chilling corresponding to flowering delays by 4.82 d°C-1, while warming during heat accumulation was associated with bloom advances by 9.85 d°C-1. Heat accumulation started after accumulating 62.7 ± 5.6 Chill Portions, and flowering occurred after a further 3744 ± 1538 Growing Degree Hours (above a base temperature of 4°C, with optimal growth at 26°C). When examining the time series, the increase in temperature during the chilling period did not appear to decrease overall chill accumulation during the chilling period but to delay the onset of chill accumulation and the completion of the the average chill accumulation necessary to start heat accumulation. The resulting delay in heat responsiveness appeared to weaken the phenology-advancing effect of spring warming. These processes may explain why apricot flowering time remained relatively unchanged despite significant temperature increases. A consequence of this may be a reduction of frost risk for early flowering crops such as apricot in the UK

Ecological and Evolutionary Benefits of Temperate Phage: What Does or Doesn't Kill You Makes You Stronger

Infection by a temperate phage can lead to death of the bacterial cell, but sometimes these phages integrate into the bacterial chromosome, offering the potential for a more long-lasting relationship to be established. Here we define three major ecological and evolutionary benefits of temperate phage for bacteria: as agents of horizontal gene transfer (HGT), as sources of genetic variation for evolutionary innovation, and as weapons of bacterial competition. We suggest that a coevolutionary perspective is required to understand the roles of temperate phages in bacterial populations

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements