Human engineering the one-handed keyboard

In certain systems and situations one-handed entry devices may have a significant advantage. This article is intended to rectify in part the dearth of basic anthropometric data and design principles that are required by designers of one-handed functional and chordic keyboards.     

Predisposition to the fragile X syndrome in Jews of Tunisian descent is due to the absence of AGG interruptions on a rare Mediterranean haplotype

Lesbians may engage in behavior that places their health at risk and may delay health care and screening more than do their heterosexual counterparts. This article examines influences on lesbians' health risk factors and health-seeking behaviors. A statewide, self-administered survey of members of a lesbian community organization was performed. Univariate and bivariate analyses were calculated, and linear regression was used to examine models of health risks and health-seeking behavior. Of 324 respondents, 90% had disclosed sexual orientation to at least one provider, 22% reported seeking care without symptoms (preventive care), and 23% reported waiting until symptoms are at their worst or never seeking care. Young age, belief in the importance of lung cancer, difficulty of getting health care when needed, reliance on the partner for health support, and fewer male partners were all associated with greater health risk for lesbians. Difficulty obtaining health care, difficulty communicating with the primary care provider, discomfort in discussing depression, and degree of comfort in discussing menopause were all associated with a delay in seeking health care. Sensitive communication with lesbians and further identification of lesbians' specific barriers to care may improve health-seeking behavior and provide more opportunities for screening and risk factor counseling in this population.     

The morphogenesis of motor rituals in rats treated chronically with the dopamine agonist quinpirole.

Rats injected repeatedly with the dopamine agonist quinpirole develop motor rituals that evolve through a cascade of 4 behavioral processes. The 1st involves increased activity. The 2nd involves increased path stereotypy, reflected in traveling repeatedly along the same few paths. The 3rd is an increase in the frequency of stopping in a few places, along with a decrease in stopping in other places. The 4th is a decrease in the repetition of movements performed in the specific stopping places. Altogether, these processes culminate in stereotypy, a typical short set of movements composed of a single performance of each movement type. Thus, stereotypy arises from changes in the temporal and spatial organization, but not the content, of behavioral patterns. These results provide a model for the development of motor rituals and their linkage to normal behavior and to the physical properties of the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lightpath arrangement in survivable rings to minimize the switchingcost

This paper studies the design of low-cost survivable wavelength-division-multiplexing (WDM) networks. To achieve survivability, lightpaths are arranged as a set of rings. Arrangement in rings is also necessary to support SONET/SDH protection schemes such as 4FBLSR above the optical layer. This is expected to be the most common architecture in regional (metro) networks. We assume that we are given a set of lightpaths in an arbitrary network topology and aim at finding a partition of the lightpaths to rings adding a minimum number of lightpaths to the original set. The cost measure that we consider (number of lightpaths) reflects the switching cost of the entire network. In the case of a SONET/SDH higher layer, the number of lightpaths is equal to the number of add-drop multiplexers (ADMs) (since two subsequent lightpaths in a ring can share an ADM at the common node). We prove some negative results on the tractability and approximability of the problem and provide an approximation algorithm with a worst case approximation ratio of 8/5. We study some special cases in which the performance of the algorithm is improved. A similar problem was introduced, motivated, and studied by Liu, Li, Wan and Frieder (see Proc. INFOCOM 2000, p.1020-1025, 2000) Gerstel, Lin and Sasaki, (see Proc. IEEE INFOCOM '98, p. 94-101, 1998)(where it was termed minimum ADM problem). However, these two works focused on a ring topology while we generalize the problem to an arbitrary network topology     

Topology optimization for the computationally poor: efficient high resolution procedures using beam modeling

A structural optimization approach based on beam modeling is formulated and investigated. Its computational efficiency and enhanced design freedom place it as a computationally cheap alternative to continuum topology optimization. The optimization uses a ground structure parametrization and consists of alternating shape and sizing-topology design phases. The sizing-topology phase controls the thicknesses of tapered beams. Linear constraints applied in the shape phase provide regularity and consistency to the structure and enable the shape design variables to benefit from large freedom of movement. A direct comparison to continuum-based topology optimization shows that the beam-based optimization can offer significant computational savings while generating designs that perform similarly to continuum designs. The result of the beam optimization can be utilized also as an effective starting point for further design iterations on a refined continuum model. The reduced computational effort facilitates the optimization of high resolution structures without separating to micro and macro scales, hence non-uniform and non-periodic porous structures can be designed in a single-level optimization process. Furthermore, the beam modeling allows to impose minimum and maximum length scales explicitly without any additional constraints. The applicability of the suggested approach is demonstrated on several cases of stiffness maximization and mechanism design.