Relation between Melting and Textural Properties of Process Cheddar Cheese

Meltability and textural characteristics were evaluated in 48 batches of process Cheddar cheese prepared in pilot plant equipment. Correlation between melting spread at 139°C and cohesiveness at 21°C was positive and large. Prolongation of cooking up to 15 min at 74°C lowered meltability and cohesiveness. Within the range of weighted average ages of cheese (3 to 5.8 mo), no relation between melting spread or cohesiveness and age was consistent.     

Evaluating Construction Failures

Four of the construction failures the writer has investigated are reviewed. Two failures involved light framed timber trusses, one failure involved precast tees, and one involved overloaded steel floor joists. Each collapse centered around a failure to recognize the weakness of a partly completed structure. Human failure was the heart of the problem. The writer suggests greater attention to details by those responsible for construction procedures.     

Lateral hypothalamic syndrome in rats: a comparison of the behavioral and neurochemical effects of lesions placed in the lateral hypothalamus and nigrostriatal bundle

The effects of total (T-NSB) and subtotal (S-NSB) destruction of the nigrostriatal bundle were compared with the effects of large lateral hypothalamic (LH) lesions on various aspects of the lateral hypothalamic syndrome. The T-NSB and LH lesions produced equivalent decreases in caudate and telencephalic contents of dopamine and norepinephrine, while with the exception of telencephalic dopamine, S-NSB lesions had consistently smaller effect. The T-NSB and LH lesions produced equivalent effects on duration of aphagia and adipsia (Stages 1 to 3) and on long-term decreases in body weight and ad lib water consumption, and these effects were always greater than those produced by the S-NSB lesion. These aspects of the lateral hypothalamic syndrome appeared to be related to the interruption of the nigrostriatal bundle and consequent decrease in caudate dopamine. The T-NSB and S-NSB lesions produced equivalent long-term deficits in water regulation as measured by drinking in the absence of food or in response to intra- and extracellular dehydration, but these deficits were always significantly less than those produced by the LH lesion. It was concluded that these regulatory deficits were not related to destruction of catecholamine pathways. All three lesions totally blocked eating in response to a glucoprivic challenge. This aspect of the lateral hypothalamic syndrome, therefore, results from destruction of a small portion of the lateral diencephalon and may be related to the interruption of the dopaminergic mesolimbic system.     

Prevalence of Escherichia coli O157 in cattle and swine in central Mexico

Escherichia coli O157:H7 is a foodborne pathogenic bacterium that can reside undetected in the gastrointestinal tract of cattle because colonization by this bacterium is asymptomatic. Recent research has indicated that swine can carry and transmit this pathogen as well. The development of more advanced and sensitive detection techniques has improved the limit of detection and increased sensitivity for this important pathogen. This study was undertaken to determine the prevalence of E. coli O157 in cattle and swine in Mexico with the more sensitive detection technique of immunomagnetic bead separation. Samples (n = 60 per farm) were taken from four cattle and four swine farms (n = 240 cattle samples, n = 240 swine samples) located throughout central Mexico in October 2001. The prevalence of E. coli O157 was found to be only 1.25% on cattle farms and 2.1% on swine farms. The prevalence in cattle in this study is lower than that reported in the United States and could be related to the lower reported prevalence of E. coli O157 in humans in Mexico. However, further research is needed to verify prevalence throughout other regions of Mexico, as well as prevalence during other seasons of the year.     

Orthographic and lexical processing of visual letter strings.

Three experiments tested whether orthographic and lexical properties of a letter string influence the time to search for a component letter. 102 Canadian undergraduates served as Ss. Orthographic redundancy, defined by single-letter position-specific frequency, facilitated the search of targets specified prior to and simultaneously with the letter string. Words were searched faster than nonwords when the target followed the letter string. Neither orthographic nor lexicality had significant effects when the position of the target within the string was certain. Results are consistent with a hierarchical-levels model of word perception in which the activation of detectors at different levels is constrained by task demands. (French abstract) (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quadratic weights for asymptotic regulator properties

This paper describes a new procedure for selecting weighting matrices in linear-quadratic optimal control designs. The procedure is based on asymptotic modal characteristics of multivariable LQ-regulators as control weights tend to zero. The asymptotic behavior of both eigenvalues and eigenvectors is used to provide complete, unique specification of the weighting matrices. The procedure is illustrated with a simplified lateral-directional flight control design example.     

Low-loss wavelength division multiplexing (WDM) devices for single-mode systems

We report here on single-mode microoptic wavelength division multiplexing (WDM) devices with two channels located at 1275 and 1345 nm, respectively. Data are presented for four multiplexers and four demultiplexers. The average insertion loss for the multiplexers was 0.5 ± 0.2 and 1.0 ± 0.3 dB for the short and long wavelength channels, respectively. For the demultiplexers, the average losses were 0.8 ± 0.2 dB and 1.0 ± 0.1 dB, respectively. The full channel widths of the demultiplexers for 0.5 dB of additional loss were about 22 nm. All measurements included the presence of prototype precision single-mode connectors. The multiplexers were based on interference filters and GRIN lenses with identical single-mode fibers used for inputs and output. The demultiplexers employed diffraction gratings and GRIN lenses with 50- μm core graded-index output fibers. In addition three of the demultiplexers included a third output channel centered at 1521 nm. The 28- dB dynamic range of the monochromator-based test appartus was insufficient to evaluate the crosstalk performance. Measurements on two demultiplexers, using a 1295-nm laser, yielded values of -33 and -38 dB, respectively for the crosstalk in the 1345-nm channel.     

Source localization and polarization determination in low frequency satellite radio astronomy

The authors review the techniques available for finding out the location and polarization of a radio source using antennas with low directivity, that is, electric or magnetic antennas with dimensions less than the wavelength. The use of such antennas is imposed by the combination of the low frequency of observation and of the dynamical constraints upon the antenna length particularly in the case of planetary probes. First they summarize the relationship of an arbitrary antenna to the parameters describing the radiation field, emphasizing the importance of the antenna polarization vector. The application of these results defines precisely the limited information available using short electric antennas. In principle, it is possible to determine the direction (except for the sense) and also the polarization of a point source, using either three such antennas on a three-axis stabilized spacecraft or two antennas on a spinning spacecraft. With a single antenna which is neither parallel nor perpendicular to the spin axis it is possible to determine the source direction with a πambiguity but not its complete polarization. If the single antenna is perpendicular to the spin axis (as is usually the case) only the great circle containing the source direction and the spin axis can be obtained, and this at the expense of assumptions about the source polarization. Source localization requires, in addition to the direction, either observations from another spacecraft or some assumption about the source mechanism and the spatial distribution of the relevant plasma parameters. The application of these methods to the observations of solar radio bursts and terrestrial kilometric radiations is presented.