Transfer of knowledge in knowledge management systems: unexplored issues and suggested studies

The management practice literature is replete with reports of practices being used to motivate a firm's knowledge workers to transfer knowledge into and out of the firm's computer resident knowledge repositories, ie, to participate with commitment in the firm's Knowledge Management System. Unfortunately, little is known with any certainty about which of these practices have what effects under which conditions. It appears that in many cases the practices are ill suited for the particular situations where they are employed, with unknown but perhaps sizeable losses in opportunities foregone because valuable knowledge is not as fully or completely transferred as is possible. In addition, it seems that some of these practices are likely to be interfering with the effectiveness of other practices, just as some drugs interfere with the potentially positive effects of other drugs. About these matters, our knowledge is exceeded by our ignorance. The paper identifies some major problems associated with knowledge transfer, and articulates some of the most important issues associated with these problems. Eight research questions are raised that, if answered with sound studies, would enable organisations to be more effective in their transfer of knowledge.     

The 2.2 A crystal structure of human chymase in complex with succinyl-Ala-Ala-Pro-Phe-chloromethylketone: structural explanation for its dipeptidyl carboxypeptidase specificity

Human chymase (HC) is a chymotrypsin-like serine proteinase expressed by mast cells. The 2.2 A crystal structure of HC complexed to the peptidyl inhibitor, succinyl-Ala-Ala-Pro-Phe-chloromethylketone (CMK), was solved and refined to a crystallographic R-factor of 18.4 %. The HC structure exhibits the typical folding pattern of a chymotrypsin-like serine proteinase, and shows particularly similarity to rat chymase 2 (rat mast cell proteinase II) and human cathepsin G. The peptidyl-CMK inhibitor is covalently bound to the active-site residues Ser195 and His57; the peptidyl moiety juxtaposes the S1 entrance frame segment 214-217 by forming a short antiparallel beta-sheet. HC is a highly efficient angiotensin-converting enzyme. Modeling of the chymase-angiotensin I interaction guided by the geometry of the bound chloromethylketone inhibitor indicates that the extended substrate binding site contains features that may generate the dipeptidyl carboxypeptidase-like activity needed for efficient cleavage and activation of the hormone. The C-terminal carboxylate group of angiotensin I docked into the active-site cleft, with the last two residues extending beyond the active site, is perfectly localized to make a favorable hydrogen bond and salt bridge with the amide nitrogen of the Lys40-Phe41 peptide bond and with the epsilon-ammonium group of the Lys40 side-chain. This amide positioning is unique to the chymase-related proteinases, and only chymases from primates possess a Lys residue at position 40. Thus, the structure conveniently explains the preferred conversion of angiotensin I to angiotensin II by human chymase.     

(±)-Catechin: Chemical Weapon,Antioxidant, or Stress Regulator?

(±)-Catechin is a flavan-3-ol that occurs in the organs of many plant species, especially fruits. Health-beneficial effects have been studied extensively, and notable toxic effects have not been found. In contrast, (±)-catechin has been implicated as a ‘chemical weapon’ that is exuded by the roots of Centaurea stoebe, an invasive knapweed of northern America. Recently, this hypothesis has been rejected based on (±)-catechin’s low phytotoxicity, instability at pH levels higher than 5, and poor recovery from soil. In the current study, (±)-catechin did not inhibit the development of white and black mustard to an extent that was comparable to the highly phytotoxic juglone, a naphthoquinone that is allegedly responsible for the allelopathy of the walnut tree. At high stress levels, caused by sub-lethal methanol concentrations in the medium, and a 12 h photoperiod, (±)-catechin even attenuated growth retardation. A similar effect was observed when (±)-catechin was assayed for brine shrimp mortality. Higher concentrations reduced the mortality caused by toxic concentrations of methanol. Further, when (±)-catechin was tested in variants of the deoxyribose degradation assay, it was an efficient scavenger of reactive oxygen species (ROS) when they were present in higher concentrations. This antioxidant effect was enhanced when iron was chelated directly by (±)-catechin. Conversely, if iron was chelated to EDTA, pro-oxidative effects were demonstrated at higher concentrations; in this case (±)-catechin reduced molecular oxygen and iron to reagents required by the Fenton reaction to produce hydroxyl radicals. A comparison of cyclic voltammograms of (±)-catechin with the phytotoxic naphthoquinone juglone indicated similar redox-cycling properties for both compounds although juglone required lower electrochemical potentials to enter redox reactions. In buffer solutions, (±)-catechin remained stable at pH 3.6 (vacuole) and decomposed at pH 7.4 (cytoplasm) after 24 h. The results support the recent rejection of the hypothesis that (±)-catechin may serve as a ‘chemical weapon’ for invasive plants. Instead, accumulation and exudation of (±)-catechin may help plants survive periods of stress.     

Surface Interaction of PuO2, UO2+x and UO3 with Water Ice

The interaction of PuO₂, UO_2+x and UO₃ with water ice was studied using ultraviolet photoelectron spectroscopy (UPS). Water was adsorbed at 80–120 K as thick ice multilayers. Surface modification after desorption of the ice around 200 K was investigated. Main information on the surface oxidation state was obtained by highly surface sensitive UPS-HeII spectra, probing primarily the first monolayer. The oxidation state was directly deduced from the intensity of the actinide 5f levels. The surface character of the phenomenon was further confirmed by comparing HeII spectra with the more bulk sensitive HeI spectra. Spectral interpretation was done using the cross-section variations in HeI and HeII spectra and by comparing the spectra with theoretical density of states curves, obtained by LSDA + U calculations. It was shown previously that reduction to Pu₂O₃ takes place, when the ice covered PuO₂ films are warmed up under UV light and ice is desorbed. In this paper, this effect was investigated in further detail. It was shown that only the top surface layer is reduced. Reduction is inhibited by surface diffusion of oxygen trapped in the films during sputter deposition and not incorporated in the lattice. UO_2+x and UO₃ also undergo reduction, but to a significant lesser extent than PuO₂. Reoxidation of surface U by bulk oxygen was much slower than that of surface Pu. It was shown that for all oxides, reduction needs the illumination of an ice overlayer by UV light. Surface reduction by atomic hydrogen was investigated to check for possible influence of ice photolysis products. UO₃ was shown to be reduced to UO₂ while PuO₂ is not further reduced. The observations are explained by photochemical decomposition of water by the UV light (used for UPS) at the oxide-ice interface. It is thought that the oxide acts as photocatalyst, absorbing light and splitting adsorbed water. The thick ice layer traps the reaction products on the surface, thereby enabling them to react and reduce the surface. Why only the reductants (probably H) and not the concomitant oxidants react with the surface is still unknown.     

Perception and preference in short-term word priming.

Responding optimally with unknown sources of evidence (ROUSE) is a theory of short-term priming applied to associative, orthographic-phonemic, and repetition priming. In our studies, perceptual identification is measured with two-alterative forced-choice testing. ROUSE assumes features activated by primes are confused with those activated by the target. A near-optimal decision discounts evidence arising from such shared features. Too little discounting explains the finding that primed words were preferred after passive viewing of primes. Too much discounting explains the findings of reverse preference after active processing of primes. These preference changes highlight the need to use paradigms (like the present ones) capable of separating preferential and perceptual components of priming. Evidence of enhanced perception was found only with associative priming and was very small in magnitude compared with preference effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bounds on information combining

When the same data sequence is transmitted over two independent channels, or when a data sequence is transmitted twice but independently over the same channel, the independent observations can be combined at the receiver side. From an information-theory point of view, the overall mutual information between the data sequence and the received sequences represents a combination of the mutual information of the two channels. This concept is termed information combining. A lower bound and an upper bound on the combined information is presented, and it is proved that these bounds are tight. Furthermore, this principle is extended to the computation of extrinsic information on single code bits for a repetition code and for a single parity-check code of length three, respectively. For illustration of the concept and the bounds on information combining, two applications are considered. First, bounds on the information processing characteristic (IPC) of a parallel concatenated code are derived from its extrinsic information transfer (EXIT) chart. Second, bounds on the EXIT chart for an outer repetition code and for an outer single parity-check code of a serially concatenated coding scheme are computed.     

Analysis of the “Crack characteristic signal” using ageneralized scattering matrix representation

Electromagnetic properties of a system formed by an open-ended rectangular waveguide and a surface crack/slot in a metallic specimen are described in this paper. Scanning a crack on a metal surface changes the reflection coefficient of the incident dominant mode. A model as a function of relative crack location within the waveguide aperture (i.e., crack moving with respect to the waveguide aperture) is desired to describe and optimize practical crack detection applications. Hence, the change in the reflection coefficient for a generalized system encompassing empty, filled, and finite cracks located at an arbitrary position inside the waveguide aperture, is evaluated. A moment solution approach is employed, and a magnetic current density M is introduced over the common aperture formed by the waveguide and the crack. Subsequently, the junction formed by the waveguide and the cracked metallic surface is separated into two systems. A numerical solution employing the method of moments is obtained, and the reflection coefficient at the waveguide aperture is expressed in terms of the generalized scattering matrix. The convergence behavior is studied to determine an optimized set of basis functions and the optimal number of higher order modes for a fast and accurate solution. Numerical results presented in this paper include the evaluation of the field distribution over the waveguide aperture. Finally, the theoretical and measured crack characteristic signals are compared     

Note on decoding binary Goppa codes

The author gives a simple expression for the polynomial y(x) which solves the polynomial equation y(x)²≡t(x) mod G(x), where t(x), y(x) and G(x) are polynomials over the field GF(2^m). The solution of such an equation is a step in the so called Patterson algorithm for decoding binary Goppa codes. The result may also be useful for other applications