Literature survey

About: Literature survey is a research topic. Over the lifetime, 15372 publications have been published within this topic receiving 459196 citations.

Guidelines for including grey literature and conducting multivocal literature reviews in software engineering

Abstract: Context A Multivocal Literature Review (MLR) is a form of a Systematic Literature Review (SLR) which includes the grey literature (e.g., blog posts, videos and white papers) in addition to the published (formal) literature (e.g., journal and conference papers). MLRs are useful for both researchers and practitioners since they provide summaries both the state-of-the art and –practice in a given area. MLRs are popular in other fields and have recently started to appear in software engineering (SE). As more MLR studies are conducted and reported, it is important to have a set of guidelines to ensure high quality of MLR processes and their results. Objective There are several guidelines to conduct SLR studies in SE. However, several phases of MLRs differ from those of traditional SLRs, for instance with respect to the search process and source quality assessment. Therefore, SLR guidelines are only partially useful for conducting MLR studies. Our goal in this paper is to present guidelines on how to conduct MLR studies in SE. Method To develop the MLR guidelines, we benefit from several inputs: (1) existing SLR guidelines in SE, (2), a literature survey of MLR guidelines and experience papers in other fields, and (3) our own experiences in conducting several MLRs in SE. We took the popular SLR guidelines of Kitchenham and Charters as the baseline and extended/adopted them to conduct MLR studies in SE. All derived guidelines are discussed in the context of an already-published MLR in SE as the running example. Results The resulting guidelines cover all phases of conducting and reporting MLRs in SE from the planning phase, over conducting the review to the final reporting of the review. In particular, we believe that incorporating and adopting a vast set of experience-based recommendations from MLR guidelines and experience papers in other fields have enabled us to propose a set of guidelines with solid foundations. Conclusion Having been developed on the basis of several types of experience and evidence, the provided MLR guidelines will support researchers to effectively and efficiently conduct new MLRs in any area of SE. The authors recommend the researchers to utilize these guidelines in their MLR studies and then share their lessons learned and experiences.

The physical properties of major aquifers in England and Wales

Abstract: This report is the result of a three-year collaborative project between the British Geological Survey and the Environment Agency. The aim of the project has been to collect, collate and present information concerning the physical hydraulic properties of the minor aquifers in England and Wales. These properties include hydraulic conductivity, porosity, transmissivity and storage coefficient. In addition, specific capacity (yield per unit drawdown) values are included for many of the formations described, together with yields for those formations where aquifer properties data are sparse. Although the parameters studied were limited in number, the study has proven to be complex for several reasons. Firstly the aquifers themselves are hydraulically complicated. They are bodies of rock, sometimes with indeterminate boundaries, which are heterogeneous either because of sedimentological factors in the case of the Cainozoic aquifers, or because of the effects of fracturing in older formations. This heterogeneity presents several problems. Firstly, hydraulic tests on such materials often violate the classical assumptions used in the test analysis, and the complexity of the aquifers makes interpolation between data points difficult. Secondly, the physical properties of the aquifers are often scale dependent, so that the value of a parameter at one scale may not be appropriate for use at a larger or smaller scale. Thirdly, there are problems of data quality and quantity which are particularly significant for these smaller aquifers. The quality of the pumping tests is variable and many results are from short duration pumping tests which are designed more to assess the yields of boreholes than to examine the properties of the aquifer. Also, data can be very irregularly distributed, being a product mainly of the evolving requirements of groundwater users and not of well-planned resource assessments. This irregular spacing can be both vertical as well as lateral, as in the case of thick structurally complex sequences with only scattered productive horizons. Awareness of these inherent hydrogeological factors dictated the project’s approach, which was to collect both data and knowledge about the aquifers. This permits the report to describe not only the magnitudes and variability of the aquifer parameters at a given tested locality, but also to provide some insight into factors controlling the properties, so that the results can be more confidently extrapolated. Project resources were therefore initially employed in data collection. This involved a detailed search through Agency records, with additional information from BGS, published and unpublished literature. Most of the data obtained were from analysed pumping tests, the results of which were entered in a database. The latter originally housed data on the major aquifers, collected under a preceding project, but the database needed to be significantly altered and expanded so as to manage efficiently the much larger number of aquifers involved. It was also linked with the BGS Core Analysis Database. The result comprises the National Aquifer Properties Database which is now a major UK geoscience resource, with data from more than 8000 pumping test analyses at over 8250 sites. The second main strand of the project was the collection and summarising of knowledge about the aquifers. In addition to the collection of reports of hydrogeological studies and a literature survey, expert opinion was canvassed. The latter is a vital source of information that is not often published. The results of these two approaches are synthesised in this report. After the introductory sections each chapter takes the form of a detailed review of the physical properties of a group of minor aquifers, subdivided as appropriate on stratigraphic or geographical grounds. The chapters are arranged in order of increasing age. The purpose of the review is to present the magnitudes and variability of the data (mainly from the database, but with other examples) in the context of current understanding of the aquifer systems involved and the controls on the data. To that end the review includes geological, geographical and physical hydrogeological aspects of the aquifers. Useful summaries of data from the database are included on the accompanying CD-ROM. The intention of the report is therefore to acquaint the reader with the aquifer properties data values that characterise the aquifers in the context of what is known about the complexities of their hydraulic structure and the physical controls on the data. The reader is specifically dissuaded from taking raw values out of context. A further purpose of the report is provide a comprehensive set of references by which the reader can obtain more detailed information about particular areas of interest in an aquifer. As a result of the collection and review of information about the physical properties of the minor aquifers in England and Wales, it is apparent that there are many areas in which knowledge is inadequate. For example, a critical comparison of the equivalent aquifer systems in the London and Hampshire basins was not possible in other than the most general terms. Similarly, the lateral variability in aquifer properties in the Lower Cretaceous aquifers of the Weald is suspected to arise partly from fault-controlled compartmentalisation, but the role of the faults is not well enough understood for predictive purposes. For all the effort expended on geological characterisation over almost two centuries of detailed study of English Jurassic rocks, the flow systems of the numerous arenaceous and carbonate minor aquifers of that system are in general poorly characterised. Very localised borehole development and the effects of tapping complex multi-aquifer sequences mean that the fracture-dominant, structurally-affected systems of older rocks of Palaeozoic age are in many cases barely conceptualised. Such gaps in our knowledge are inevitable considering the paucity of data. Nevertheless, the project has provided the first opportunity to review comprehensively the aquifer properties of this second rank of British aquifers whose role is so important in providing local sources of water supply for both private and public use.

In vivo Near-Infrared Fluorescence Imaging of Integrin αvβ3 in Brain Tumor Xenografts

Abstract: Noninvasive visualization of cell adhesion molecule alpha(v)beta(3) integrin expression in vivo has been well studied by using the radionuclide imaging modalities in various preclinical tumor models. A literature survey indicated no previous use of cyanine dyes as contrast agents for in vivo optical detection of tumor integrin. Herein, we report the integrin receptor specificity of novel peptide-dye conjugate arginine-glycine-aspartic acid (RGD)-Cy5.5 as a contrast agent in vitro, in vivo, and ex vivo. The RGD-Cy5.5 exhibited intermediate affinity for alpha(v)beta(3) integrin (IC(50) = 58.1 +/- 5.6 nmol/L). The conjugate led to elevated cell-associated fluorescence on integrin-expressing tumor cells and endothelial cells and produced minimal cell fluorescence when coincubated with c(RGDyK). In vivo imaging with a prototype three-dimensional small-animal imaging system visualized subcutaneous U87MG glioblastoma xenograft with a broad range of concentrations of fluorescent probe administered via the tail vein. The intermediate dose (0.5 nmol) produces better tumor contrast than high dose (3 nmol) and low dose (0.1 nmol) during 30 minutes to 24 hours postinjection, because of partial self-inhibition of receptor-specific tumor uptake at high dose and the presence of significant amount of background fluorescence at low dose, respectively. The tumor contrast was also dependent on the mouse viewing angles. Tumor uptake of RGD-Cy5.5 was blocked by unlabeled c(RGDyK). This study suggests that the combination of the specificity of RGD peptide/integrin interaction with near-infrared fluorescence detection may be applied to noninvasive imaging of integrin expression and monitoring anti-integrin treatment efficacy providing near real-time measurements.