Demonstration of a robust pseudogap in a three-dimensional correlated electronic system

We outline a partial-fractions decomposition method for determining the one-particle spectral function and single-particle density of states of a correlated electronic system on a finite lattice in the non self-consistent T-matrix approximation to arbitrary numerical accuracy, and demonstrate the application of these ideas to the attractive Hubbard model. We then demonstrate the effectiveness of a finite-size scaling ansatz which allows for the extraction of quantities of interest in the thermodynamic limit from this method. In this approximation, in one or two dimensions, for any finite lattice or in the thermodynamic limit, a pseudogap is present and its energy diverges as Tc is approached from above; this is an unphysical manifestation of using an approximation that predicts a spurious phase transition in one or two dimensions. However, in three dimensions one expects the transition predicted by this approximation to represent a true continuous phase transition, and in the thermodynamic limit any pseudogap predicted by this formulation will remain finite. We have applied our method to the attractive Hubbard model on a three-dimensional simple cubic lattice, and find that for intermediate coupling a prominent pseudogap is found in the single-particle density of states, and this gap persists over a large temperature range. In addition, we also show that for weak coupling a pseudogap is also present. The pseudogap energy at the transition temperature is almost a factor of three larger than the T=0 BCS gap for intermediate coupling, whereas for weak coupling the pseudogap and BCS gap energies are essentially equal.Comment: 28 pages, 9 figure

Surgical treatment of necrotizing enterocolitis: when? how?

In 10 years (1981 - 1990) 28 out of 54 neonates (51.8%) with definite necrotizing enterocolitis (NEC) underwenl surgery. Operation was performed al 13.5 ± 8.8 (range 3 38) days of lifc, after 1.7 f 1.5 (range 1 --6) days from the onset of symptoms. Aiming to perform laparotomy before the occurrence of perforation, surgery was liberally indicated in stage IIIa, according to Walsh-Kliegman. Explorative laparotorny (+pcritoneal drainage in 2 cases) was performed in 4 patients with massive intestinal necrosis: all died within 3 days of surgery. In one neonate, only pneumatosis was present and resection was not considered mandatory. Intestinal resection and enterostorny was performed in 17 neonates, 5 of them with perforation; three developed an intestinal stenosis. 6nterostomy was closed after 116.2 f 61.8 days (range 26--193); 11 patients (64.7%) are long-terni survivors. Intestinal resection and primary anastomosis was performed in 6 babics, 3 of them with perforation. Postoperatively, 2 dehiscences and 1 stenosis avere recorded, but all children survived. In our opinion, resection followed by primary anastomosis seans to bc the most salisfactory surgical optio

Spontaneous rhythm discrimination in a mammalian vocal learner

Rhythm and vocal production learning are building blocks of human music and speech. Vocal learning has been hypothesized as a prerequisite for rhythmic capacities. Yet, no mammalian vocal learner but humans have shown the capacity to flexibly and spontaneously discriminate rhythmic patterns. Here we tested untrained rhythm discrimination in a mammalian vocal learning species, the harbour seal (Phoca vitulina). Twenty wild-born seals were exposed to music-like playbacks of conspecific call sequences varying in basic rhythmic properties. These properties were called length, sequence regularity, and overall tempo. All three features significantly influenced seals' reaction (number of looks and their duration), demonstrating spontaneous rhythm discrimination in a vocal learning mammal. This finding supports the rhythm–vocal learning hypothesis and showcases pinnipeds as promising models for comparative research on rhythmic phylogenies

Comparison of video and direct observation methods for measuring oral behaviour in veal calves

Measuring behaviour, especially oral behaviour, has always been a debated issue: therefore the aim of this paper is to closely examine the study of oral behaviour in calves and the approaching methodology. Behavioural observations were conducted by two media (direct observations by check sheets and indirect observations by videotapes recorded by cam- eras connected to a digital field switcher and a time-lapse video recorder) in order to compare data and assess the reli- ability and validity of the two methods in identifying some oral behavioural patterns in calves. The study was carried out on 54 Polish Friesian calves housed in group pens and in individual crates. The behaviour of the calves was investigated during the fattening period on the 2nd, 7th, 13th, 18th and 23rd week, one hour before and one hour after each of the two meals. Two experienced observers checked the behaviour of the calves, including oral behaviours on structures and buckets and oral stereotypies, by direct observations using a scan sampling every 2 min- utes. The calves' behaviour was also video recorded on the same days in which the direct observations were carried out and analysed by the same two observers. Percentages of time spent on each type of behaviour were calculated and anal- ysed by Chi-square test. Regardless of the housing system, the comparison between direct and indirect observations revealed significant differences in almost every behavioural category. Licking, biting and nibbling structures, nibbling and sucking the bucket, playing with the bucket and the teat, chewing and oral stereotypies were significantly higher in direct observations compared to indirect (P < 0.001), while inactivity was higher in video recorded observations (P < 0.001). In conclusion, regardless of the type of housing, our results revealed an objective difficulty in analysing videotapes with very detailed behavioural categories, like oral behaviours. Although video recording can certainly represent a useful and practical alternative to direct observations in many situations, the video recording system used in this study for investi- gating calves' oral behaviour, in spite of the use of multiple cameras, could not replace direct observations, probably due to the restricted field of view, the low depth of focus, the black and white vision, the lack of audio and the time-lapse feature

Propuesta metodol?gica para rescatar los valores y mejorar la convivencia escolar

99 p. Recurso Electr?nicoLa presente propuesta metodol?gica est? dirigida aquellos ni?os y ni?as del grado (2-4) para el rescate de los valores y mejorar la convivencia escolar, es una propuesta que favorece a las docentes y padres de familia y a la Instituci?n Educativa Francisco de Paula Santander en tener las alternativas para incentivar en los estudiantes las relaciones interpersonales pacificas con los dem?s en un ambiente de respeto y tolerancia. En consecuencia, esta propuesta cuenta con un itinerario de referentes te?ricos que dan respuesta a la necesidad que tiene la instituci?n educativa para el rescate de los valores y motivar a la participaci?n de todos los miembros de comunidad educativa para que sea posible. Igualmente, para continuar con este proceso se hizo necesario la aplicaci?n de encuestas a los ni?os y ni?as, padres de familia y docentes y conocer las concepciones que tienen cada uno de ellos acerca de los valores para la sana convivencia escolar, por lo tanto, esta propuesta propone una serie de actividades y talleres l?dicos pedag?gicos para fortalecimiento de los valores. Palabras Clave: Resoluci?n de conflictos, convivencia escolar, valores, propuesta, comunidad educativa.This proposal is aimed at those children of grade (2-4) for the rescue of values and improve school coexistence, is a proposal that favors teachers and parents and the Educational Institution Francisco de Paula Santander in having the alternatives to encourage students to have peaceful interpersonal relationships with others in an environment of respect and tolerance. In consecuentica, this proposal has an itinerary of theoretical referents that respond to the need of the educational institution for the rescue of values and motivate the participation of all members of the educational community to make it possible. Likewise, in order to continue with this process, it became necessary to apply surveys to children, parents and teachers and to know the conceptions that each of them has about the values for healthy school coexistence, therefore, this The proposal proposes a series of pedagogical play activities and workshops to strengthen values. Keywords: Conflict resolution, school coexistence, values, proposal, educational community

Exploring SnxTi1-xO2 Solid Solutions Grown onto Graphene Oxide (GO) as Selective Toluene Gas Sensors

The major drawback of oxide-based sensors is the lack of selectivity. In this context, SnxTi1- xO2/graphene oxide (GO)-based materials were synthesized via a simple hydrothermal route, varying the titanium content in the tin dioxide matrix. Then, toluene and acetone gas sensing performances of the as-prepared sensors were systematically investigated. Specifically, by using 32:1 SnO2/GO and 32:1 TiO2/GO, a greater selectivity towards acetone analyte, also at room temperature, was obtained even at ppb level. However, solid solutions possessing a higher content of tin relative to titanium (as 32:1 Sn0.55Ti0.45O2/GO) exhibited higher selectivity towards bigger and non-polar molecules (such as toluene) at 350 \ub0C, rather than acetone. A deep experimental investigation of structural (XRPD and Raman), morphological (SEM, TEM, BET surface area and pores volume) and surface (XPS analyses) properties allowed us to give a feasible explanation of the different selectivity. Moreover, by exploiting the UV light, the lowest operating temperature to obtain a significant and reliable signal was 250 \ub0C, keeping the greater selectivity to the toluene analyte. Hence, the feasibility of tuning the chemical selectivity by engineering the relative amount of SnO2 and TiO2 is a promising feature that may guide the future development of miniaturized chemoresistors

Long-term effects of a multidisciplinary treatment of uncomplicated obesity on carotid intima-media thickness

Obesity is associated with well-known cardiovascular risk factors and a lower life expectancy. This study investigated whether nonoperative nutritional treatment of obesity without comorbidities influenced the carotid intima-media thickness (c-IMT) in the long run. Fifty-four subjects of an original cohort of 251 subjects were re-evaluated 10 years after a medical nutritional treatment (MNT) with cognitive-behavioral approach for uncomplicated obesity. Forty subjects were classified as failure (10-year body weight change >0.5 kg) and 14 (body weight change 640.5 kg) as a success of the MNT. Ten years after MNT, c-IMT significantly increased (0.06 \ub1 0.02 mm; P = 0.004) in the failure group and significantly decreased ( 120.07 \ub1 0.03 mm; P = 0.027) in the success group. Ten-year change in c-IMT correlated significantly with 10-year change in body weight (r = 0.28; P = 0.040). Multiple stepwise linear regression analysis demonstrated that age, final BMI, and group (success or failure) influenced independently the 10-year c-IMT. In conclusion, this study is in agreement with the possibility that the successful MNT of obesity may be an effective choice in the long run and seems to indicate that it may be able to reduce the cardiovascular risk as reflected by the change in c-IMT