Dialectical Inquiry: A Structured Qualitative Research Method

This paper presents Dialectical Inquiry (DI) as a structured qualitative research method for studying participant models of organizational processes. The method is applied to rich secondary anecdotal data on technology transfer, gathered by subject-matter experts in a large firm. DI assumes that the imposition of a dialectical structure will produce emergent theories in tacit use by organizational actors. As such, it serves as a meta-structure for grounded rese arch. Three competing models were discovered in the data. Each model was analyzed in the context of other models to reveal governing assumptions and counter assumptions. It is demonstrated that each model grasps essential truths, but is necessarily incomplete, and would fail due to internal contradictions. The internal and external validity of the results were tested in a manner consistent with qualitative researc

Force Field Generalization and the Internal Representation of Motor Learning

When learning a new motor behavior, e.g. reaching in a force field, the nervous system builds an internal representation. Examining how subsequent reaches in unpracticed directions generalize reveals this representation. Though it is the subject of frequent studies, it is not known how this representation changes across training directions, or how changes in reach direction and the corresponding changes in limb impedance, influence measurements of it. We ran a force field adaptation experiment using eight groups of subjects each trained on one of eight standard directions and then tested for generalization in the remaining seven directions. Generalization in all directions was local and asymmetric, providing limited and unequal transfer to the left and right side of the trained target. These asymmetries were not consistent in either magnitude or direction even after correcting for changes in limb impedance, at odds with previous explanations. Relying on a standard model for generalization the inferred representations inconsistently shifted to one side or the other of their respective training direction. A second model that accounted for limb impedance and variations in baseline trajectories explained more data and the inferred representations were centered on their respective training directions. Our results highlight the influence of limb mechanics and impedance on psychophysical measurements and their interpretations for motor learning.Comment: Accepted for Publication in PLoS One Journa

Spontaneous Reporting Systems: Achieving Less Spontaneity and More Reporting

The purpose of this article is to highlight and analyze possible improvements to spontaneous reporting systems, in particular, and drug safety, in general. Part I of this article will provide a background on adverse drug reactions and spontaneous reporting systems, with particular emphasis on the MedWatch reporting system currently used in the United States. Part II will discuss physician attitudinal studies performed worldwide that have attempted to highlight the reasons for the underreporting of adverse reactions and problems with reporting systems. Part III will analyze problems identified with spontaneous reporting systems and potential improvements of them

Linearity, motor primitives and low-dimensionality in the spinal organization of motor control

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 149-154).The typical biological system is nonlinear, high-dimensional and highly redundant, all of which are burdens on controller design. Yet despite these complications, the central nervous system is able to control motor systems with an impressive level of complexity and effectivity. One such example is the frog. Evidence suggests that in frogs, the central nervous system, and the spinal cord in particular, may adopt simplifying strategies to ease the motor control problem. For instance, despite the known nonlinear nature of muscle, it has been demonstrated experimentally that spinally induced force production in the frog limb is linear in stimulation. Spinally encoded force fields have also been implicated as building blocks for generating hind limb movements. Furthermore, muscle EMG measurements for both intact and spinalized animals, have been shown to be low-dimensional; these measurements can be reconstructed as linear combinations of fixed muscle activations, or synergies. The evidence above suggests that the central nervous system may adopt simplifying strategies for the motor control problem. First, the thesis addresses the issue of linearity in isometric force fields. It proposes that this behavior can be explained as a result of biomechanical properties. To this end, a physiologically realistic model of the frog hind limb is analyzed.(cont.) The results suggest that, due to features of the musculo-skeletal structure, forces produced by the hind limb muscles are linear in activation, in large part and within the limb's workspace. The results, therefore, support our hypothesis that muscle forces which scale linearly in activation are a natural biomechanical result. The second portion of the thesis centers on the evidence of low-dimensional motor commands and the hypothesized motor primitives (in the form both of force fields and of muscle synergies). Many investigations have examined muscle synergies, probed motor behaviors for modular features in the form of force fields, and looked for connections between synergies and force fields. However, this work has largely been descriptive in nature, trying to explain the data without reference to the underlying control structure. We offer a principled explanation for motor primitives, for how force fields and synergies arise, and for how they are implicated in the organization of motor control. A controller that utilizes a reduced order model is proposed. Using apparatuses drawn from model order reduction theory, a method for finding a low-dimensional model that estimates a nonlinear model of the frog hind limb is examined. A formalism for defining motor primitives is proposed and the resulting primitives are compared with experimentally derived synergies.(cont.) The motor primitives are found to correspond well with several synergies, and to offer practical interpretations in terms of limb biomechanics. The reduced model is shown to be capable of generating natural motor behaviors as well as optimal control solutions. The evidence suggests that frog hind limb motor behaviors, and the spinal circuitry that coordinates these behaviors, are consistent with a control architecture that utilizes a reduced order model of the musculo-skeletal system in an effort to simplify motor control.by Max Berniker.Ph.D

Reductoonops.

75 pages : illustrations (some color) ; 26 cm. Part of the oonopid PBI project. (Acknowledgments)A new genus, Reductoonops, is established for a group of New World soft-bodied oonopine spiders, found from Mexico south to Chile, characterized by reduced size, a flattened clypeus, loss of the posterior median spinnerets, and often by loss of the four posterior eyes. Members of this group resemble those of Stenoonops Simon but lack the clump of short setae found on the dorsal surface of the palpal tarsus of both sexes in that genus, and often have four pairs of deep channels at the sides of the sternum, the most anterior pair of which demarcate a short, trapezoidal, anterior portion of the sternum. A total of 34 new species are described from Mexico (chamela, armeria, niltepec, real, nubes, jabin), Costa Rica (monte, lucha), Costa Rica and Panama (naci), Panama (almirante, escopeta, bayano), Jamaica (ferry), Curaçao (hato), Martinique (diamant), Colombia (marta, sasaima, meta, leticia), Ecuador (tandapi, pichincha, tina, domingo, otonga, palenque, napo, jatun, hedlite, molleturo, celica, yasuni), the Galapagos Islands (pinta), Peru (carpish), and Chile (elqui)

Costarina.

67 pages : illustrations (some color) ; 26 cm. Parts 1 and 2 issued as no. 3730 and no. 3794 of American Museum novitates. Part of the oonopid PBI project. (Acknowledgments)The Costarina faunas of Panama and Colombia are revised. Because Chickering described the sexes from his Panamanian collections separately, several of his names based only on females are placed as junior synonyms of names based only on males: C. humphreyi (Chickering) is newly synonymized with C. recondita (Chickering), as are C. belinda (Chickering) with C. intempina (Chickering), C. rigida (Chickering) with C. abdita (Chickering), C. silvatica (Chickering) with C. dura (Chickering), and C. improvisa (Chickering) with C. seclusa (Chickering). The Costa Rican species C. pittier Platnick and Berniker is newly recorded from Panama. Nine new species are described from Panama (C. sorkini, cerrocol, bocas, chiriqui, clara, fortuna, almirante, dybasi, and tskui), as are 11 from Colombia (C. sasaima, suiza, otun, choco, yotoco, saladito, antonio, anchicaya, gorgona, helechal, and taraira). Previous studies on more northern species are supplemented; newly available collections from Nicaragua reveal the presence there of two new species (C. kilambe and diablo), and locality records are provided for the Costa Rican members of the genus

Noonops.

48 pages : illustrations (some color) ; 26 cm. Part of the oonopid PBI project. Cf. acknowledgments.A new genus, Noonops, is established to contain 23 species of soft-bodied, New World oonopine spiders that differ from those of Oonops Templeton and similar genera in having the male palpal bulb fused to the cymbium, and from those of Wanops Chamberlin and Ivie and Oonopoides Bryant in having shorter legs. Six specific names are transferred from Oonops to Noonops: O. floridanus (Chamberlin and Ivie) from Florida and Georgia (chosen as the type species), O. gertschi Chickering from the Bahama Islands (which is placed as a junior synonym of N. floridanus), O. furtivus Gertsch from Texas and Tamaulipas, O. sonora Gertsch and Davis from Arizona, California, Sonora, Baja California, and Baja California Sur, O. puebla Gertsch and Davis from Puebla, and O. chilapensis Chamberlin and Ivie from Guerrero. Males of N. sonora and females of N. furtivus are described for the first time; 18 new species are described: N. ocotillo, N. mortero, N. joshua, N. skinner, N. coachella, and N. californicus from Arizona and southern California and N. willisi, N. mesa, N. naci, N. tarantula, N. miraflores, N. culiacan, N. taxquillo, N. chapul, N. beattyi, N. iviei, N. tonila, and N. minutus from Mexico

Oonopoides.

38 pages : illustrations (some color) ; 26 cm. Part of the oonopid PBI project. (Acknowledgments)The goblin spider genus Oonopoides Bryant was established for a species from Cuba, Oonopoides maxillaris Bryant, and most of the species that have subsequently been assigned to the genus are from that island. The group is actually circum-Caribbean in distribution, but many of its members have been misplaced in the genus Oonops Templeton; here we treat those representatives of the genus that have been collected in North and Central America. Six specific names are transferred from Oonops to Oonopoides: O. endicus Chickering from Florida and the Bahama Islands, O. secretus Gertsch from Texas and Tamaulipas, O mitchelli Gertsch from Mexico, and O. pallidulus (Chickering), O. tenebus Chickering, and O. anoxus Chickering from Panama. Males of O. zullinii Brignoli from Mexico and females of O. secretus are described for the first time; O. tenebus is placed as the male, and hence a junior synonym, of O. pallidulus. The holotype of Oonops zeteki Chickering from Panama is a juvenile that probably belongs to Costarina Platnick and Dupérré and the name is placed as a nomen dubium. Eight new species are described: O. iviei from Florida and the Bahama Islands, O. catemaco, O. chicanna, and O. kaplanae from Mexico, O. hondo from Honduras, O. cristo and O. upala from Costa Rica, and O. cartago from Costa Rica and Panama

Prodysderina, Aschnaoonops, and Bidysderina.

102 p. : ill. ; 26 cm.A new genus, Prodysderina, is established for a group of Neotropical oonopids belonging to the Dysderina complex and characterized by having a laterally incised, tuberculate, but unridged sternum, a groove connecting the posterior (but not the anterior) spiracles, and a male embolus with an elongated distal prong and a reduced proximal prong. Dysderina armata Simon is transferred to Prodysderina and selected as the type species; eight new species are described from Venezuela (P. megarmata, P. rollardae, P. janetae) and Colombia (P. piedecuesta, P. rasgon, P. santander, P. filandia, P. otun). The genus Aschnaoonops contains species that resemble those of Prodysderina but have a twisted (and usually basally widened) embolus in males, and a reduced genital atrium in females. That genus occurs in the Andes from Peru north to Colombia, east across northern South America, and north into the West Indies. Dysderina similis (Keyserling) and D. propinqua (Keyserling) from Colombia, and D. simla Chickering from Trinidad, are transferred to Aschnaoonops, and females of the two Keyserling species are described for the first time. One new species, A. silvae, has been taken by canopy fogging and appears to be widespread in the Amazonian portions of Peru, Ecuador, and Colombia. A total of 36 other new, ground-dwelling, microdistributed species are described: A. yasuni, A. tiputini, A. cosanga, A. ramirezi, A. jatun, and A. marshalli from Ecuador, A. leticia, A. orito, A. pira, A. paez, A. huila, A. meta, A. alban, A. chingaza, A. pamplona, A. pedro, and A. marta from Colombia, A. chorro, A. indio, A. tachira, A. tariba, A. teleferico, A. jaji, A. merida, A. aquada, A. masneri, A. trujillo, A. cristalina, A. bocono, A. simoni, and A. margaretae from Venezuela, A. malkini, A. caninde, and A. belem from Brazil, A. villalba from Puerto Rico, and A. gorda from the Virgin Islands. Another new genus, Bidysderina, is established for a group of species resembling those above in sternal structure but having differently constructed male palps; five new species (B. perdido, B. bifida, B. niarchos, B. wagra, B. cayambe) are described from Napo province, Ecuador