A longitudinal examination of the social-cognitive model applied to high school girls' choices of nontraditional college majors and aspirations.

This study tested a partial version of R. W. Lent, S. D. Brown, and G. Hackett's (1994) social-cognitive career theory model. Among 204 high school girls who attended science, math, and engineering (SME) career conferences, the authors used a 4-year longitudinal design to predict the choice of an SME college major and SME self-efficacy and outcome expectations in college. In addition, among students who had declared SME majors, variables assessed in high school and college were used to predict aspirations to become leaders in SME fields. The results generally provided empirical validation of the model. Regression analyses revealed that college SME outcome expectations were associated with plans to become a leader in an SME field. Implications for research and interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fine-tuning Food Safety Objectives and risk assessment

Food Safety Objectives (FSOs) have been proposed as a practical tool to translate public health targets for food safety into tolerable levels of pathogens in a food product. The FSO concept is subject to intensive debate, and has not been developed in detail. We evaluate the proposed definition of FSOs and their implementation from the perspective of Quantitative Microbiological Risk Assessment (QMRA). The relationship between QMRA and FSOs is illustrated by a model for the public health risk of Shiga-producing Escherichia coli in steak tartare. We conclude that the proposed definition of FSOs needs to be modified to properly account for variability in and uncertainty about the contamination of food with pathogenic microorganisms and emphasize that both prevalence and concentration of pathogens must be considered. For this purpose, we propose the P-D equivalence curve, a simple graphical tool to separate "tolerable" from "non-tolerable" combinations of prevalence and concentration (dose).     

Linear CMOS transconductance element for VHF filters

A differential transconductance element based on CMOS inverters is presented. With this circuit a linear, tunable integrator for very high-frequency continuous-time integrated filters can be made. This integrator has good linearity properties (THD<0.04%, V/sub ipp/=1.8 V), nondominant poles in the gigahertz range and a 40 dB DC gain.<>     

Analog circuits in ultra-deep-submicron CMOS

Modern and future ultra-deep-submicron (UDSM) technologies introduce several new problems in analog design. Nonlinear output conductance in combination with reduced voltage gain pose limits in linearity of (feedback) circuits. Gate-leakage mismatch exceeds conventional matching tolerances. Increasing area does not improve matching any more, except if higher power consumption is accepted or if active cancellation techniques are used. Another issue is the drop in supply voltages. Operating critical parts at higher supply voltages by exploiting combinations of thin- and thick-oxide transistors can solve this problem. Composite transistors are presented to solve this problem in a practical way. Practical rules of thumb based on measurements are derived for the above phenomena.     

Comparisons of organizational constraints and their relations to strains in China and the United States.

Organizational constraints is an important source of job stress. To study the relations between organizational constraints and four indices of job strains in cross-cultural work settings, both self-report and coworker-report data were collected from university employees in two culturally dissimilar countries: China and the United States. As predicted, U.S. university employees reported more interpersonal constraints than did their Chinese counterparts. No country difference was found for job context constraints. Both self-report and coworker-report data revealed significant correlations between organizational constraints and job strains in both countries. Country moderated the relations between interpersonal constraints and negative emotions/job satisfaction/voluntary lateness, with stronger correlations in the United States than in China. Country also moderated the relations between job context constraints and all four indicators of job strains, indicating that U.S. university employees were more sensitive to workplace constraints than were their Chinese counterparts. Suggestions are provided for future research and practice applications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A robust 43-GHz VCO in CMOS for OC-768 SONET applications

In this paper, we present a 43-GHz LC-VCO in 0.13-/spl mu/m CMOS for use in SONET OC-768 optical networks. A tuned output buffer is used to provide 1.3 V/sub p-p/ (single-ended) into a 90-fF capacitive load as is required when the VCO is used in typical clock and data recovery (CDR) circuits. Phase noise is -90 dBc/Hz at a 1-MHz offset from the carrier; this meets SONET jitter specifications. The design has a tune range of 4.2%. The VCO, including output buffers, consumes 14 mA from a 1-V supply and occupies 0.06 mm/sup 2/ of die area. Modern CMOS process characteristics and the high center frequency of this design mean that the tank loss is not dominated by the integrated inductor, but rather by the tank capacitance. An area-efficient inductor design that does not require any optimization is used.     

Bandwidth of integrated photodiodes in standard CMOS for CD/DVD applications

This paper analyzes the bandwidth of high-speed photodiodes in a fully standard 0.18 μm CMOS technology for the CD/DVD optical pick-up units. Three diode structures are investigated: nwell/p-substrate, p+/nwell/p-substrate and p+/nwell. The photodiode performances are compared for λ = 780 nm and λ = 650 nm wavelength, corresponding to the lasers for CD and DVD, respectively. Slow substrate photocurrent component limits the bandwidth of nwell/p-substrate and p+/nwell/p-substrate photodiodes to 6 MHz and 7 MHz for a CD application as well as 70 MHz and 100 MHz for a DVD application. The third analyzed photodiode has bandwidth in the low GHz range for both applications, with the cost of at least 12 dB lower responsivity.     

Analog line driver with adaptive impedance matching

A new principle for an adaptive line driver is presented. This type of line driver can adapt its output impedance automatically to the applied load. This results in automatically corrected output impedance for different cables with terminations. Also, the line-driver output impedance becomes insensitive to process variations. As an example, a line driver for analog video signals has been designed. The circuit operates from a 2.4-V supply in a 0.35-μm CMOS technology. The realized circuit adapts between 38 and 85 Ω loads, has total harmonic distortion of <-50 dB at 1.2 V_pp for 0-10 MHz, 0.09-mm² area, and 9-mW static power consumption     

A 2.5-10-GHz clock multiplier unit with 0.22-ps RMS jitter in standard 0.18-/spl mu/m CMOS

This paper demonstrates a low-jitter clock multiplier unit that generates a 10-GHz output clock from a 2.5-GHz reference clock. An integrated 10-GHz LC oscillator is locked to the input clock, using a simple and fast phase detector circuit that overcomes the speed limitation of a conventional tri-state phase frequency detector due to the lack of an internal feedback loop. A frequency detector guarantees PLL locking without degenerating jitter performance. The clock multiplier is implemented in a standard 0.18-/spl mu/m CMOS process and achieves a jitter generation of 0.22 ps while consuming 100 mW power from a 1.8-V supply.