Teaching Design to Freshmen: Style and Content

This paper describe a freshman course in engineering design that stresses the open-ended and ill-structured nature of design in a project-based context. The projects are chosen in part for their social context and utility. The projects are supplemented by lectures on design methodology and other topics related to engineering practice. Among the deliverables required of the students are proposals, progress reports, and written and oral presentations—the latter to an external design jury as part of a design competition.     

Electron Thermalization in Metallic Islands Probed by Coulomb Blockade Thermometry

We describe a systematic series of experiments on thermalization of electrons in lithographic metallic thin films at millikelvin temperatures using Coulomb blockade thermometry (CBT). Joule dissipation due to biasing of the CBT sensor tends to drive the electron system into non-equilibrium. Under all experimental conditions tested, the electron-electron relaxation is fast enough to ensure thermal electron distribution, which is also in agreement with the theoretical arguments we present. On the other hand, poor electron-phonon relaxation plays a dominant role in lifting the electron temperature above that of the bath. From a comparison of the results with the theoretical current-voltage characteristics of the thermometers we precisely determine the electron-phonon coupling constant for the common metals used. Our experiments show that it is a formidable task to attain thermal equilibrium with the bath using single-electron devices under non-zero bias conditions at 20–50 mK temperatures that are typically encountered in experiments. The conclusion concerning Coulomb blockade thermometry is more optimistic and two-fold: (1) One can now correct the errors due to bias heating in a satisfactory manner based on known material properties and the size of the metal films in the sensor. (2) Reliable thermometry down to 20 mK requires islands whose volumes are >10^?15 m³, which is still acceptable both from the parameter (capacitance) and fabrication points of view.     

Homophily of Network Ties and Bonding and Bridging Social Capital in Computer-Mediated Distributed Teams

This research studied homophily of network ties in distributed teams in both task-related instrumental networks and non-task related expressive networks. Homophily of network ties was examined in terms of demographic and social characteristics, including gender, race, geographic location, and group assignment. Social network data were collected from 32 students enrolled in a distance learning class from two universities. MQAP regression analysis showed that homophily in gender and in race had no significant impact on the development of either instrumental or expressive ties. In instrumental networks, both homophily in group assignment and in location had significant impact on the development of network ties. In expressive networks, homophily in location had significant impact on the development of network ties, but the impact of homophily in group membership was only marginally significant. Further analysis of bonding ties with people of the same group and bridging ties with people from different groups showed that bonding social capital can exert significant influence on performance.     

Citrullinemia: management and clinical course. Apropos of a familial case

The authors report two cases of citrullinemia in siblings which add to 68 observations from the literature. They overview the clinical presentation, diagnosis and therapeutic management of the disease. The prognosis of severe neonatal form remains poor but an early adequate management may contribute to an acceptable outcome.     

Sociotropy and autonomy: Differential patterns of clinical presentation in unipolar depression.

We examined the relations between sociotropy and autonomy and clinical features of depression. A. T. Beck (1983) proposed that sociotropy is related to a sense of deprivation and clinical features associated with reactive depression and that autonomy is related to a sense of defeat and clinical features associated with endogenous depression. C. J. Robins et al (see record 1989-19204-001) found support for the hypothesis for sociotropy but not for autonomy, and they suggested that the autonomy scale may be problematic. We administered new measures of sociotropy and autonomy and a more comprehensive assessment of clinical features to 50 unipolar depressed inpatients. The results support the selective relations of both sociotropy and autonomy to the predicted sets of clinical features. This study adds to the growing evidence that these personality dimensions are important to the understanding of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improved cellulase production by stable Clostridium cellulolyticum mutants

Methods for the production of mutants of the cellulase producer Clostridium cellulolyticum ATCC 35319 were examined using an agar plate screening technique. Spontaneous and UV light-induced mutants were isolated, some of which exhibited a high level of both endoglucanase and exoglucanase activities as assayed using CMC (carboxymethyl cellulose) and PNPCb (paranitrophenyi-β-cellobioside) respectively. The volumetric enzyme activities were up to 2.5 times those of the wild strain.     

In Google We Trust: Users' Decisions on Rank, Position, and Relevance

An eye tracking experiment revealed that college student users have substantial trust in Google's ability to rank results by their true relevance to the query. When the participants selected a link to follow from Google's result pages, their decisions were strongly biased towards links higher in position even if the abstracts themselves were less relevant. While the participants reacted to artificially reduced retrieval quality by greater scrutiny, they failed to achieve the same success rate. This demonstrated trust in Google has implications for the search engine's tremendous potential influence on culture, society, and user traffic on the Web.     

A generalist herbivore in a specialist mode Metabolic,sequestrative, and defensive consequences

Adults of a generalist herbivore, the lubber grasshopper,Romalea guttata, can be converted to functional specialists by feeding them exclusively on catnip,Nepeta cataria. No obvious adverse effects on adult development resulted from this enforced monophagy. Notwithstanding the fact thatR. guttata has had no coevolutionary relationship with this Eurasian mint, it readily sequesters compounds that are identical to or derived from the terpenoid lactones that are characteristic ofN. cataria. R. guttata appears to both biomagnify minor allelochemicals and to sequester metabolites of theNepeta terpenes in its paired defensive glands. The levels of autogenously produced phenolics are not affected by feeding onN. cataria and the defensive secretions of catnip-fed grasshoppers are more repellent to ants than those of wild-fed acridids. Metabolites of theN. cataria monoterpenes are sequestered in the defensive glands when catnip is added to the natural diet ofR. guttata. The ability of a generalist,R. guttata, to facilely bioaccumulate a potpourri of foreign allelochemicals when feeding in a specialist mode is analyzed in terms of its biochemical, physiological, and functional significance. Sequestration is examined as a response to the enteric effronteries represented by the phytochemicals that can be characteristic of the overload in a monophagous diet.