The rapid structured literature review as a research strategy

A diversity of sources of literature encompassed by the management disciplines appears to result in a growing need for a systematic methodology to map the territory of management theory. As such, when scoping out a study, structured literature review (SLR) can be considered as a means by which any critical, central literature might be considered. However, there is little guidance, or evidence, of this being undertaken for the purposes of small scale projects such as undergraduate or masters’ dissertations. This paper reports four case studies of master’s degree students following management programmes of undertaking a structured literature review (SLR) and the issues and problems they had to encounter during their journey. The findings from the case studies suggest that in terms of time to complete and the volume of output required in terms of word count, Tranfield, et al’s approach to SLRs, whilst suited to doctoral level research is not appropriate generally when dealing with undergraduate and masters research projects. Therefore, this paper provides accounts of the experiences of four students who undertook SLR for their undergraduate or master’s degree dissertation. The paper identifies that these students had to deal with a new set of conceptual problems relating to this “unorthodox” approach to a postgraduate research dissertation in coming to terms with new paradigms of enquiry that are not normally taught as part of a traditional research methods course. This was despite gaining a greater depth of insight into the subject area through a more rigorous and structured manner. The paper presents alternative remedies by way of a rapid structured literature review (RSLR) model. This would appear to be more appropriate to the conducting of small scale literature based research projects when used with undergraduate and master’s degree students than SLR identified for other research activities

Determination of positron annihilation lifetime spectroscopy instrument timing resolution function and source terms using standard samples

The extraction of material positron lifetime components from positron annihilation lifetime spectroscopy measurements, performed using conventional unmoderated radionuclide positron sources, requires accurate knowledge of both the spectrometer instrument timing resolution function (IRF) and annihilation events extrinsic to the material, the source correction terms. Here we report the results from study of spectrometer performance made using two reference samples, high purity polycrystalline aluminium, and stainless steel supplied by the National Metrology Institute of Japan (NMIJ RM 5607-a). Both prepared with directly deposited 22NaCl positron sources. The IRFs obtained by fitting spectra from both reference samples were monitored with time to evaluate spectrometer stability and to compare methods of IRF determination. Using the aluminium IRFs the analysis of spectra from the NMIJ stainless steel reference samples yielded a single lifetime component with value 106.9(9) ps

Undertaking a structured literature review or structuring a literature review: tales from the field

The diversity of sources of literature within the management disciplines has resulted in a growing need for a systematic methodology to map the territory of its associated theories and models. As such, when scoping out a doctoral or policy based study the Structured Literature Review (SLR) can be considered as a means by which critical literature central to and underpinning the research can be rigorously and systematically mapped out. However, there is little guidance, or evidence, of this being the case when undertaking small scale projects for example undergraduate or masters degree dissertations. This paper reports four case studies using semi-structured interviews of masters degree students following management programmes who undertook a Structured Literature Review based dissertation and the issues and problems they had to encounter during their journey. The findings from the case studies suggest that the approach to SLRs, whilst suited to doctoral level and policy based research is not appropriate when dealing with undergraduate and masters dissertations and projects. The case study findings identified that these students conducting a SLR had to deal with a new set of conceptual, methodological and data collection problems relating to this ‘unorthodox’ approach to conducting a postgraduate research dissertation. The findings show that students had to confront new paradigms of enquiry that are not normally taught or found in ‘traditional’ research texts and research methods courses that are taught on degree programmes. However, the findings do reveal that students gained a greater depth and insight into the subject they were researching through a more rigorous and structured approach. The paper then presents alternative remedies by way of the Rapid Structured Literature Review (RSLR) research strategy which is argued as an appropriate approach in conducting small scale literature based research projects when used with undergraduate and masters degree students rather than the SLR, which is better suited for other types of research such as doctoral and policy based activities

First-Order Reorientation of the Flux-Line Lattice in CaAlSi

The flux line lattice in CaAlSi has been studied by small angle neutron scattering. A well defined hexagonal flux line lattice is seen just above Hc1 in an applied field of only 54 Oe. A 30 degree reorientation of this vortex lattice has been observed in a very low field of 200 Oe. This reorientation transition appears to be of first-order and could be explained by non-local effects. The magnetic field dependence of the form factor is well described by a single penetration depth of 1496(1) angstroms and a single coherence length of 307(1) angstroms at 2 K. At 1.5 K the penetration depth anisotropy is 2.7(1) with the field applied perpendicular to the c axis and agrees with the coherence length anisotropy determined from critical field measurements.Comment: 5 pages including 6 figures, to appear in Physical Review Letter

Anomalous thermal expansion in 1D transition-metal cyanides: what makes the novel trimetallic cyanide Cu1/3Ag1/3Au1/3CN behave differently?

The structural dynamics of a quasi-one-dimensional (1D) mixed-metal cyanide, Cu1/3Ag1/3Au1/3CN, with intriguing thermal properties is explored. All the current known related compounds with straight-chain structures, such as group 11 cyanides CuCN, AgCN, AuCN and bimetallic cyanides MxM’1-xCN (M, M’ = Cu, Ag, Au), exhibit 1D negative thermal expansion (NTE) along the chains and positive thermal expansion (PTE) perpendicular to them. Cu1/3Ag1/3Au1/3CN exhibits similar PTE perpendicular to the chains, however PTE, rather than NTE, is also observed along the chains. In order to understand the origin of this unexpected behavior, inelastic neutron scattering (INS) measurements were carried out, underpinned by lattice-dynamical density-functional-theory (DFT) calculations. Synchrotron-based pair-distribution-function (PDF) analysis and 13C solid-state nuclear-magnetic-resonance (SSNMR) measurements were also performed to build an input structural model for the lattice dynamical study. The results indicate that transverse motions of the metal ions are responsible for the PTE perpendicular to the chains, as is the case for the related group 11 cyanides. However NTE along the chain due to the tension effect of these transverse motions is not observed. As there are different metal-to-cyanide bond lengths in Cu1/3Ag1/3Au1/3CN, the metals in neighboring chains cannot all be truly co-planar in a straight-chain model. For this system, DFT-based phonon calculations predict small PTE along the chain due to low-energy chain-slipping modes induced by a bond-rotation effect on the weak metallophilic bonds. However the observed PTE is greater than that predicted with the straight-chain model. Small bends in the chain to accommodate truly co-planar metals provide an alternative explanation for thermal behavior. These would mitigate the tension effect induced by the transverse motions of the metals and, as temperature increases and the chains move further apart, a straightening could occur resulting in the observed PTE. This hypothesis is further supported by unusual evolution in the phonon spectra, which suggest small changes in local symmetry with temperature

Social flocculation in plant–animal worms

Individual animals can often move more safely or more efficiently as members of a group. This can be as simple as safety in numbers or as sophisticated as aerodynamic or hydrodynamic cooperation. Here, we show that individual plant–animal worms (Symsagittifera roscoffensis) can move to safety more quickly through flocculation. Flocs form in response to turbulence that might otherwise carry these beach-dwelling worms out to sea. They allow the worms to descend much more quickly to the safety of the substrate than single worms could swim. Descent speed increases with floc size such that larger flocs can catch up with smaller ones and engulf them to become even larger and faster. To our knowledge, this is the first demonstration of social flocculation in a wild, multicellular organism. It is also remarkable that such effective flocculation occurs where the components are comparatively large multicellular organisms organized as entangled ensembles

Structural and Magnetic Investigations of Single-Crystals of the Neodymium Zirconate Pyrochlore, Nd2Zr2O7

We report structural and magnetic properties studies of large high quality single-crystals of the frustrated magnet, Nd$_2$Zr$_2$O$_7$. Powder x-ray diffraction analysis confirms that Nd$_2$Zr$_2$O$_7$ adopts the pyrochlore structure. Room-temperature x-ray diffraction and time-of-flight neutron scattering experiments show that the crystals are stoichiometric in composition with no measurable site disorder. The temperature dependence of the magnetic susceptibility shows no magnetic ordering at temperatures down to 0.5 K. Fits to the magnetic susceptibility data using a Curie-Weiss law reveal a ferromagnetic coupling between the Nd moments. Magnetization versus field measurements show a local Ising anisotropy along the axes of the Nd$^{3+}$ ions in the ground state. Specific heat versus temperature measurements in zero applied magnetic field indicate the presence of a thermal anomaly below $T\sim7$ K, but no evidence of magnetic ordering is observed down to 0.5 K. The experimental temperature dependence of the single-crystal bulk dc susceptibility and isothermal magnetization are analyzed using crystal field theory and the crystal field parameters and exchange coupling constants determined.Comment: 10 pages, 6 figures, 4 tables. Accepted for publication in Physical Review

Angular and radial correlation in doubly excited systems when 1 ≤ Z ≤ 4. The 2p2 3P state

The angular and radial components of electron correlation have each been examined in detail for the discrete 2p2 3P states of H-, He, Li+ and Be2+. These doubly excited systems were described by highly accurate explicitly correlated wavefunctions. The analysis involved the use of angular Coulomb holes, changes in the one- and two-particle radial density distributions and several angular and radial expectation values. Additionally, various statistical correlation coefficients were used which emphasized, in turn, angular and radial correlation properties in different regions of the two-particle density. The angular holes and related properties showed a clearly defined inverse-Z effect for He and the positive ions. This trend was not repeated for the radial curves. However, the radial densities did reveal a distinct \u27in-out\u27 correlation effect-similar in character to the split-shell behaviour for the ground state. By comparison with the findings for Z ≥ 2, the angular and radial correlation effects for H- were always exceedingly large, thus setting it apart from the other systems. For He, the angular hole for the comparatively slow moving 2p2 3P electrons was found to be over 50% deeper than that for the ground state and about six times the depth of a 1s2p 3P hole. The statistical correlation coefficients highlighted a steady growth, with Z, in the relative importance of angular correlation. Nevertheless, for each system, these coefficients indicated that the radial effect was the prevailing influence on the two-particle probability distribution

The doubly-excited state 2p 2 3P for 1 ≤ Z ≤ 4: Coulomb holes derived from explicitly correlated wavefunctions

Doubly-excited states (DES) of simple atoms involve, by comparison with the ground state, relatively slow moving electrons which should therefore be more responsive to electron correlation. Hence, for the 2p 23P state, correlation effects have been analyzed in detail in terms of Coulomb holes, partial Coulomb holes and (r n 12) when 1 ≤ Z ≤ 4. Comparisons are made with the 1s 2 1S ground state and with the singly-excited state 1s2p, 3P. As for the lower states, each DES was described by an accurate explicitly correlated wavefunction. For each Z, a similarity of characteristics, but not of scale, is found between the DES results and those for the ground state. The Coulomb holes for the 1s2p 3P states have a significantly different shape. The correlation effect for each DES system exceeds that for the corresponding lower states examined here. © 1992 IOP Pvblishing Ltd