Effect of different storage conditions on E. coli O157:H7 and the indigenous bacterial microflora on lamb meat

Lamb chops inoculated with 2.23-2.83 log cfu/g of E. coli O157:H7 strain NCTC 12900 were packed in air (AP), vacuum (VP), and two modified atmospheres (MAP) consisting of 100% CO2 and a commercial mixture of 35% CO2/35% O2/30% N2. All samples (initial total counts <3.5 log cfu/g) were stored in a commercial cold storage facility set at 4 degrees C and one AP trial also at 12+/-1 degrees C in a temperature controlled incubator. Pathogen and indigenous flora evolution, physicochemical and sensory changes, surface packages temperature and MAP gas composition were monitored throughout the lamb meat shelf life. Temperature monitoring revealed that during chilled storage packed chops exceeded 7 degrees C about 3% of the time for periods of 10-20 min at 6 h intervals corresponding to defrosting cycles. In AP samples under these conditions, the E. coli O157:H7 strain had an overall increase of 0.48 log cfu/g by day 12. This increase, which may be regarded as an artefact of the sampling procedure, might also be a response to fluctuating temperatures. Regardless of rapid proliferation of the background microflora on AP lamb meat kept at 12+/-1 degrees C, the pathogen significantly increased by 2.35 log cfu/g after nine days. There was a slight decrease (0.20 log cfu/g) of the pathogen numbers after four weeks cold storage in VP despite a significant increase in lactic acid bacteria (LAB). With a relatively small outgrowth of LAB, chilled storage in 100% and 35% CO2 resulted in significant differences compared to similar conditions in air (decrease from initial numbers of 0.80 and 0.45 log cfu/g, respectively). Our data confirm the importance of effective temperature control to prevent pathogen growth on raw meat and also that contaminated meat remains hazardous regardless of refrigeration and protective packaging. Further studies are needed to determine the behaviour of E. coli O157:H7 at temperatures that fluctuate around the minimum for growth.     

Live weight and sex effects on carcass and meat quality of "Borrego terrincho-PDO" suckling lambs

Fifty seven suckling lambs (28 males and 29 females) of the Churra da Terra Quente breed were used to evaluate the effects of live weight and sex on carcass composition and meat quality traits. Lambs were slaughtered at three weight classes (<8 kg, 8–11 kg and >11 kg) according to “Borrego Terrincho–PDO” specifications. The left sides of the carcasses were totally dissected. The longissimus thoracis and lumborum muscle was used for meat quality determination. Dressing proportion and carcass fatness were not affected by weight class or sex. Muscle proportion was similar in all carcass joints for the three weight classes. The percentage of bone decreased at the higher weight class, while that of subcutaneous and intermuscular fat increased. Female lambs had higher muscle proportions and greater muscle/bone ratios in the carcass side than males. Muscle pH, colour, cooking losses and tenderness were not affected by gender and weight class. Female lambs and weight classes 8–11 kg and >11 kg had higher proportions of intramuscular fat.     

Deposition of ultrafine aerosol particles on wire screens by simultaneous diffusion and image force

This paper presents the results of an experimental investigation on the deposition of multiply charged particles on wire screens by the combined mechanisms of diffusion and image force. Experiments were performed with particles having diameters between 25 and 65 nm (transition regime), carrying 0, +1, +2 or +3 elementary charges, and using three different flow rates, two types of wire screen, and two types of test aerosol. The single fiber efficiencies for the mechanisms of image force, η_IM, and diffusion, η_D, are of the same order of magnitude and, furthermore, they are both much smaller than one. Under these conditions, the total capture efficiency can be approximated as the sum of the efficiencies by diffusion and image force deposition. Theoretically, η_IM is proportional to the square root of a dimensionless number, K_IM, which includes all the relevant parameters cited above (i.e., particle size and charge, aerosol flow rate and screen geometry). The available correlations for η_IM, obtained from experiments with particles carrying a large number of elementary charges (K_IM>10^-5), predict that image force should not have any effect in the case of the small particles with very few number of charges that we have tested in our experiments (in our experimentation, K_IM ranged between 10^-7 and 10^-5). Our results, the only ones available to date for this particle size range, show that there is indeed a clear, measurable effect. Although our experimental results are best fitted by the correlation , it is shown that the expression , which is in agreement with the theoretical 1/2 exponent for K_IM, also reproduces reasonably well the measured values.     

Toward Language-dependent Applications

Is adaptation of English NLP applications the right way to gomultilingual? Should one prefer ``language-independent'' systems with aview to applying them to a large number of different languages? Experience from the processing of Portuguese in several differentareas (part-of-speech tagging, corpus tools, lexical decomposition,machine translation, etc.) suggests that neither of these offers a satisfactory solution. This paper argues for a thorough study of the way individual languageswork in order to develop applications suited for the language inquestion, i.e., ``language-dependent'' systems.     

Mapping the gene causing hereditary primary hyperparathyroidism in a Portuguese kindred to chromosome 1q22-q31

A Portuguese kindred with autosomal dominant isolated primary hyperparathyroidism (HPT) that was associated with parathyroid adenomas and carcinomas was investigated with the aim of determining the chromosomal location of this gene, designated HPTPort. Leukocyte DNA from 9 affected and 16 unaffected members and 7 parathyroid tumors from 4 patients was used in comparative genomic hybridization (CGH), tumor loss of heterozygosity (LOH), and family linkage studies. The CGH studies revealed abnormalities of chromosomes 1 and 13, and the results of LOH studies were consistent with the involvements of tumor suppressor genes from these regions. Family segregation studies mapped HPTPort to chromosome 1q22-q31 by establishing linkage with eight loci (D1S254, D1S222, D1S202, D1S238, D1S428, D1S2877, D1S422, and D1S412) (peak two-point LOD scores = 3. 46-5.14 at 0% recombination), and defined the location of HPT Port to a 21 cM region flanked centromerically by D1S215 and telomerically by D1S306. Thus, HPTPort has been mapped to chromosome 1q22-q31, and a characterization of this gene will help to elucidate further the mechanisms that are involved in the development of parathyroid tumors.     

A buck quadratic PWM soft-switching converter using a single activeswitch

High-switching frequency associated with soft commutation techniques is a trend in switching converters. Following this trend, a buck pulsewidth modulation (PWM) converter is presented. The DC voltage conversion ratio of this converter has a quadratic dependence on duty cycle, providing a large stepdown. This new buck quadratic PWM soft-single-switched converter, having only a single active switch, provides a high efficient operating condition for a wide load range at high-switching frequency. In order to illustrate the operating principle of this new converter, a detailed study including theoretical analysis, relevant equations and simulation, and experimental results is carried out     

Constraints on problem solving and inhibition: Object retrieval in cotton-top tamarins (Saguinus oedipus oedipus).

Problem solving relies on a combination of the capacity to generate appropriate solutions and the ability to inhibit prepotent inappropriate responses. Often, problems with the latter prevent some animals from performing well on problem-solving tasks. The authors used the object retrieval task to examine inhibition in cotton-top tamarins (Saguinus oedipus oedipus). They found that, like human infants, tamarins had difficulty retrieving a reward from inside a transparent box when the opening was on the side because they could not inhibit the tendency to reach straight into the solid face of the box. However, subjects trained with an opaque box prior to testing on the transparent box performed perfectly. These results suggest that although the inability to inhibit prepotent biases prevents individuals from acquiring an initial strategy, sufficient training on an effective strategy may allow animals to overcome their initial difficulties with tasks requiring inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dose-dependent induction of distinct anergic phenotypes: multiple levels of T cell anergy

T cell anergy has been proposed as one of the mechanisms underlying peripheral T cell tolerance. In recent years, the functional relevance of T cell anergy has been studied extensively in vitro and in vivo, using different species, cell systems, and ways to induce anergy. Although these studies concurred about the induction of unresponsiveness, conflicting findings were obtained with respect to the function of anergic T cells and to the persistence of T cell anergy. In the present study, T cell anergy was induced through T-T presentation of the specific Ag by rat MHC class II+ T cells in the absence of professional APC. We show that, depending on the Ag dose with which T cells were incubated, distinct anergic phenotypes were induced. Incubation of T cell clones with a low (suboptimal) Ag dose induced hyporesponsiveness. Incubation with a higher (optimal) Ag dose induced an anergic state capable of exerting immunoregulatory effects. Incubation with a high (supraoptimal) Ag dose led to an anergic suppressive phenotype that was persistent and was not reversed by APC, Ag, and rIL-2. These findings demonstrate that T cell anergy is not confined to a single state of functional inactivation. Instead, multiple levels of T cell anergy exist. Thus, anergic T cells can contribute to the regulation of the immune response either in a persistent and active manner or in a passive manner, depending on their level of T cell anergy.     

Study of hydraulic transients in hydropower plants throughsimulation of nonlinear model of penstock and hydraulic turbine model

Study of hydraulic transients in hydropower plants specifically in hydraulic turbine units, with penstock, spiral case and draft tube-is necessary due to power and frequency oscillations which normally occur in generator units, mainly during load rejections. In turn, this causes large pressure and subpressure oscillations in turbine hydraulic systems and must be evaluated to avoid mechanical failures. In this context, this work analyses discrete hydraulic systems with emphasis on hydraulic parameter analysis. The simulation used was developed based on analog mathematical models of transient phenomenon equations and on a hydro turbine model. The results were obtained by using a nonlinear analog-digital simulation method. Comparisons between results of a theoretical simulation of a literature example using the characteristics method and the results obtained with the present method are presented. Theoretical simulation results obtained from a 360 MW turbine and experimental results are also confronted