Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

Construction Learning as a Function of Frequency, Frequency Distribution, and Function.

Abstract: This article considers effects of construction frequency, form, function, and prototypicality on second language acquisition (SLA). It investigates these relationships by focusing on naturalistic SLA in the European Science Foundation corpus ( Perdue, 1993 ) of the English verb–argument constructions (VACs): verb locative (VL), verb object locative (VOL), and ditransitive (VOO). Goldberg (2006) argued that Zipfian type/token frequency distributions ( Zipf, 1935 ) in natural language constructions might optimize learning by providing one very high-frequency exemplar that is also prototypical in meaning. This article tests and confirms this proposal for naturalistic English as a second language. We show that VAC type/token distribution in the input is Zipfian and that learners first use the most frequent, prototypical, and generic exemplar (e.g., put in the VOL VAC, give in the VOO ditransitive, etc.). Learning is driven by the frequency and frequency distribution of exemplars within constructions and by the match of their meaning to the construction prototype. [ABSTRACT FROM AUTHOR]

Gaseous supramolecules of imidazolium ionic liquids: "magic" numbers and intrinsic strengths of hydrogen bonds.

Abstract: Electrospray ionization mass spectrometry (ESI-MS) is found to gently and efficiently transfer small to large as well as singly to multiply charged [X + ] n [A - ] m supramolecules of imidazolium ion (X + ) ionic liquids to the gas phase, and to reveal "magic numbers" for their most favored assemblies. Tandem mass spectrometric experiments (ESI-MS/MS) were then used to dissociate, via low-energy collision activation, mixed and loosely bonded [A-----X-----A'] - and [X-----A-----X'] + gaseous supramolecules, as well as their higher homologues, and to estimate and order via Cooks' kinetic method (CKM) and B3LYP/6-311G(d,p) calculations the intrinsic solvent-free magnitude of hydrogen bonds. For the five anions studied, the relative order of intrinsic hydrogen-bond strengths to the 1-n-butyl-3-methylimidazolium ion [X 1 ] + is: CF 3 CO 2 - (zero) > BF 4 - (-3.1) > PF 6 - (-10.0) > InCl 4 - (-16.4) and BPh 4 - (-17.6 kcal mol - 1 ). The relative hydrogen-bond strength for InCl 4 - was measured via CKM whereas those for the other anions were calculated and used as CKM references. A good correlation coefficient (R=0.998) between fragment ion ratios and calculated hydrogen-bond strengths and an effective temperature (T e f f ) of 430 K demonstrate the CKM reliability for measuring hydrogen-bond strengths in gaseous ionic liquid supramolecules. Using CKM and T e f f of 430 K, the intrinsic hydrogen-bond strengths of BF 4 - for the three cations investigated is: 1-n-butyl-3-methyl-imidazolium ion (0) > 1,3-di-[(R)-3-methyl-2-butyl]-imidazolium ion (-2.4) > 1,3-di-[(R)-α-methylbenzyl]-imidazolium ion (-3.0 kcal mol - 1 ). As evidenced by "magic" numbers, greater stabilities are found for the [(X 1 ) 2 (BF 4 ) 3 ] - and [(X 1 ) 5 A 4 ] + supramolecules (A ≠ InCl 4 - ).

GR3J: a daily watershed model with three free parameters

Abstract: This paper describes a new empirical watershed model, the prime feature of which is its parsimony. It involves only three free parameters, a characteristic unparalleled by continuous process models able to work on a wide array of catchments. In spite of its crude simplicity, it achieved, on average, worthwhile results on a set of 140 French catchments and overwhelmingly outperformed a linear model involving 16 parameters. It performed roughly as well as a conceptual model with five free parameters, derived from the well-known TOPMODEL.