Situated learning theory versus traditional cognitive learning theory: Why management education should not ignore management learning

This paper describes the differences between situated learning theory (SLT) and traditional cognitive theory (TCT). SLT is distinctive because it perceives learning to be a socially relational rather than a mentalist process. SLT places research attention upon knowledge productionin situ and in the course of work practices rather than upon learning transmission in the classroom. This paper argues that SLT's emphasis on the social context of learning is problematic and ambiguous. SLT sees context as pregiven, which is consistent with modernist thought, but also sees it as emergent, which is more consistent with postmodern thought. The implications of this are discussed and the SLT-TCT debate is used to shed light on management education from the perspective of management learning.     

Birth of a relativistic outflow in the unusual γ-ray transient Swift J164449.3+573451

Active galactic nuclei, which are powered by long-term accretion onto central supermassive black holes, produce relativistic jets with lifetimes of at least one million years, and the observation of the birth of such a jet is therefore unlikely. Transient accretion onto a supermassive black hole, for example through the tidal disruption of a stray star, thus offers a rare opportunity to study the birth of a relativistic jet. On 25 March 2011, an unusual transient source (Swift J164449.3+573451) was found, potentially representing such an accretion event. Here we report observations spanning centimetre to millimetre wavelengths and covering the first month of evolution of a luminous radio transient associated with Swift J164449.3+573451. The radio transient coincides with the nucleus of an inactive galaxy. We conclude that we are seeing a newly formed relativistic outflow, launched by transient accretion onto a million-solar-mass black hole. A relativistic outflow is not predicted in this situation, but we show that the tidal disruption of a star naturally explains the observed high-energy properties and radio luminosity and the inferred rate of such events. The weaker beaming in the radio-frequency spectrum relative to γ-rays or X-rays suggests that radio searches may uncover similar events out to redshifts of z?≈?6.     

Bats associated with inactive mines in the Great Basin

We surveyed bats using echolocation calls near inactive mines in the western Great Basin from 2003 to 2007. We identified 14 species of bats during our surveys, with Myotis lucifugus and Lasionycteris noctivagans found at 9 sites and Myotis evotis and Tadarida brasiliensis at 7 sites; all other species were found at less than one-half of the sites. Euderma maculatum, a state-protected species in Nevada, was recorded at 2 sites. Our work provides information that will be useful in managing bat habitat, especially with regard to mining activities.     

Structural and serological evidence for a novel mechanism of antigenic variation in foot-and-mouth disease virus.

Changes resulting in altered antigenic properties of viruses nearly always occur on their surface and have been attributed to the substitution of residues directly involved in binding antibody. To investigate the mechanism of antigenic variation in foot-and-mouth disease virus (FMDV), variants that escape neutralization by a monoclonal antibody have been compared crystallographically and serologically with parental virus. FMDVs form one of the four genera of the Picornaviridae. The unenveloped icosahedral shell comprises 60 copies each of four structural proteins VP1-4. Representatives from each of the genera have similar overall structure, but differences in the external features. For example, human rhinovirus has a pronounced 'canyon' that is proposed to contain the cell attachment site, whereas elements of the attachment site for FMDV, which involves the G-H loop (residues 134-160) and C-terminus (200-213) of VP1, are exposed on the surface. Moreover, this G-H loop, which is a major antigenic site of FMDV, forms a prominent, highly accessible protrusion, a feature not seen in other picornaviruses. It is this loop that is perturbed in the variant viruses that we have studied. The amino acid mutations characterizing the variants are not at positions directly involved in antibody binding, but result in far-reaching perturbations of the surface structure of the virus. Thus, this virus seems to use a novel escape mechanism whereby an induced conformational change in a major antigenic loop destroys the integrity of the epitope.     

sRNA methylase activity of embryonic liver

Résumé Utilisant SAM-¹⁴CH₃ il a été démontré que le foie foetal a plus d'activité de sRNA methylase que le foie adulte.

---

---

This investigation was supported in part by an allocation from a Public Health Service General Research Support Grant No. SO 1 FR-05545-03, and an American Cancer Society Grant No. IN 19F to The Jackson Laboratory, Bar Harbor, Maine, and by Public Health Service Research Grants No. HD-01496 from the National Institute of Child Health and Human Development and No. FR-00251 from the Division of Research Facilities and Resources.     

On the role of carbonic anhydrase in the anticonvulsant effects of triethyltin (TET)

Summary Triethyltin (TET) and acetazolamide (ACTZ) both produce marked anticonvulsant effects as evaluated by the maximal electroshock seizure test. However, the mechanism responsible for the anticonvulsant effect of TET and ACTZ is probably not the same since TET does not inhibit the activity of carbonic anhydrase isozyme C in vitro.This study was supported by NIEHS Toxicology Training grant No. ES07 090, NIOSH grant No. OH07085 and a University of Texas Biomedical Research grant. We wish to thank Rebecca Crenshaw for her excellent technical assistance.     

Some observations on pigments of the pacific sand dollars,Dendraster excentricus andDentraster laevis

Zusammenfassung Dendraster laevis bildet ein grünes, wasserlösliches Pigment (farblos bei pH unter 5) und kein Echinochrom.Dendraster excentricus dagegen erzeugt zwei purpurrote, wasserlösliche und zwei echinochromähnliche Pigmente.

---

---

Contribution from the Scripps Institution of Oceanography, University of California, New Series No 773.