A collated digital, geological map database for the central Namaqua Province using geographical information system technology

The genlogy of the Namaqua Province is notoriously difficult to map and interpret due to polymetamorphic and multiple deformation events and limlted outcrop. Current maps of the Province reflect diverse interpretations of stratigraphy as a consequence of these difficulties. A Geographic Information System is essentially a digital database and a set of functions and procedures to capture, analyse and manipulate spatially related data. A GIS is therefore ideally suited to the study and analysis of maps. A digital map database was established, using modem GIS technology, to facilitate the collation of existing maps of an area in the Central Namaqua Province (CNP). This database is based on a lithological classification system similar to that used by Harris (1992), rather than on an interpretive stratigraphic model. In order to establish the database, existing geological maps were scanned into a GIS, and lines of outcrop and lithological contacts were digitised using a manual line following process, which is one of the functions native to a GIS. Attribute data were then attached to the resultant polygons. The attribute database consists of lithological, textural and mineralogical data, as well as stratigraphical classification data according to the South African Committee for Stratigraphy (SACS), correlative names assigned to units by the Precambrian Research Unit, the Geological Survey of South Africa, the Bushmanland Research group and the University of the Orange Free State. Other attribute data included in the database, are tectonic and absolute age information, and the terrane classification for the area. This database reflects the main objective of the project and also serves as a basis for further expansion of a geological GIS for the CNP. Cartographic and database capabilities of the GIS were employed to produce a collated lithological map of the CNP. A TNTmipsTM Spatial Manipulation Language routine was written to produce a database containing two fields linked to each polygon, one for lithology and one for a correlation probability factor. Correlation factors are calculated in this routine from three variables, namely the prominence a worker attached to a specific lithology within a unit or outcrop, the agreement amongst the various workers on the actual lithology present within an outcrop, and the correspondence between the source of the spatial element (mapped outcrop) and the source of the attribute data attached to it. Outcrops were displayed on the map according to the lithology with the highest correlation factor, providing a unique view of the spatial relationships and distribution patterns of lithological units in the CNP. A second map was produced indicating the correlation factors for lithologies within the CNP. Thematic maps are produced in a GIS by selecting spatial elements according to a set of criteria, usually based on the attribute database, and then displaying the elements as maps. Maps created by this process are known as customised maps, since users of the GIS can customise the selection and display of elements according to their needs. For instance, all outcrops of rock units containing particular lithologies of a given age occurring in a specific terrane can be displayed - either on screen or printed out as a map. The database also makes it possible to plot maps according to different stratigraphic classification systems. Areas where various workers disagree on the stratigraphic classification of units can be isolated, and displayed as separate maps in order to aid in the collation process. The database can assist SACS in identifying areas in the CNP where stratigraphic classification is still lacking or agreements on stratigraphic nomenclature have not yet been attained. More than one database can be attached to the spatial elements in a GIS, and the Namaqua-GIS can therefore be expanded to include geochemical, geophysical, economic, structural and geographical data. Other data on the area, such as more detailed maps, photographs and satellite images can be attached to the lithological map database in the correct spatial relationship. Another advantage of a GIS is the facility to continually update the database(s) as more information becomes available and/or as interpretation of the area is refined

Studying Complex Adaptive Systems

Complex adaptive systems (cas) – systems that involve many components that adapt or learn as they interact – are at the heart of important contemporary problems. The study of cas poses unique challenges: Some of our most powerful mathematical tools, particularly methods involving fixed points, attractors, and the like, are of limited help in understanding the development of cas. This paper suggests ways to modify research methods and tools, with an emphasis on the role of computer-based models, to increase our understanding of cas.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41486/1/11424_2006_Article_1.pd

Ion-nanostructure interaction: comparing simulation and experiment towards surface structuring using nanoparticles

Nanotechnology is a buzzword in context of the proceeding miniaturization of devices and their components. Nanoparticles (NPs) can nowadays easily be synthesized from different material compositions by different chemical and physical processes. However, most of these techniques work close to or at the thermal equilibrium. One subsequent approach to tune materials beyond equilibrium conditions is ion beam irradiation. An important effect of this approach is sputtering. Sputtering is enhanced in NPs compared to their bulk counterparts due to their large surface-to-volume ratio, especially when the ion range matches the NP size. In this work, the sputtering effects of Ar+ and Ga+ ion irradiated Au nanoparticles are investigated in detail by Monte Carlo (MC) and molecular dynamics (MD) simulations and a variety of experiments. The sputtering of Ar+ and Ga+ irradiated Au NPs was investigated as a function of ion energy, NP size and impact parameter by the MC code iradina and MD code parcas. The simulation results are directly compared to experiments using high resolution scanning electron microscopy (SEM) of Au NPs on top of Si, whereat the sputter yields are significantly enhanced compared to the MC simulations. Additionally, the interaction of NPs and substrate were investigated by Rutherford backscatter spectrometry (RBS), atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). A new MC code was developed to study the redeposition of sputtered atoms of Ga+ irradiated Au NP arrays on neighboring NPs. The redeposition can lead to growth of NPs with diameters of 1 nm in vicinity of ~50 nm NP. These simulations are directly compared to an in situ experiment. Nanostructures, spherical NPs as well as nanowires (NWs) are used as irradiation masks to structure lithium niobate (LNO) using the ion beam enhanced etching (IBEE) technique. The aspect ratio of the obtained structures can be enhanced by a second IBEE step after annealing

Concerning the emergence of tag-mediated lookahead in classifier systems

This paper, after a general introduction to the area, discusses the architecture and learning algorithms that permit automatic parallel, distributed lookahead to emerge in classifier systems. Simple additions to a "standard" classifier system suffice, principally a new register called the virtual strength register, and a provision to use the bucket brigade credit assignment algorithm in "virtual" mode to modify values in this register. With these additions, current actions are decided on the basis of the expected values associated with the "lookahead cones" of possible alternatives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28531/1/0000328.pd

Cycles in logical nets

This paper investigates the influence of cycles in a logical net upon the complexity of its behavior. The investigation is mainly concerned with two questions: 1. 1. A logical net with a periodic input sequence produces a periodic output sequence; how is the spectrum of periodic outputs related to the level of cycle complexity?2. 2. Is there a level of complexity c (suitably defined) such that any behavior possible for a fixed logical net can be realized by a logical net constructed only of cycles of complexity c' [les] c? The first and more difficult question is fully answered only in the case of nets constructed of cycles having a feedback coefficient r = 1 (suitably defined). The second question is answered in the negative for individual cycles and it is conjectured that a similar answer holds for nets in general.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32404/1/0000479.pd

A systematic review of smoking cessation and relapse prevention interventions in parents of babies admitted to a neonatal unit (after delivery):Protocol

PROSPERO International prospective register of systematic review

Sputtering and redeposition of ion irradiated Au nanoparticle arrays : direct comparison of simulations to experiments

Ion beam processing of surfaces is well known to lead to sputtering, which conventionally is associated only with erosion of atoms from the material. We show here, by combination of experiments and a newly developed Monte Carlo algorithm, that in the case of nanoparticles in a regular two-dimensional array on surfaces, the redeposition of sputtered atoms may play a significant role on the system development. The simulations are directly compared to in situ experiments obtained using a dual focused Ga+ ion beam system and high resolution scanning electron microscopy, and explain the size evolution by a combination of sputtering and redeposition of sputtered material on neighboring particles. The effect is found to be dependent on the size of the nanoparticles: if the nanoparticle size is comparable to the ion range, the reposition is negligible. For larger nanoparticles the redeposition becomes significant and is able to compensate up to 20% of the sputtered material, effectively reducing the process of sputtering. The redeposition may even lead to significant growth: this was seen for the nanoparticles with the sizes much smaller than the ion range. Furthermore, the algorithm shows that significant redeposition is possible when the large size neighboring nanoparticles are present.Peer reviewe

From Combat Zones to the Classroom: Transitional Adjustment in OEF/OIF Student Veterans

With 600,000 veterans of Operations Enduring Freedom and Iraqi Freedom enrolled in higher education with the Post-9/11 GI Bill, recognizing and responding to their predictable adjustment issues is imperative. Existing qualitative research has identified some transitional issues encountered by small groups of veterans. Because of qualitative research’s limited generalizability, however, themes may be viewed as more generalizable when corroborated by student veterans in different regions. In order to provide an in-depth description of the themes related to the post-deployment adjustment process, the first author conducted semi-structured interviews with 19 student veterans from a Southwestern community college who were returning to civilian life after deployment to Afghanistan or Iraq. The first author and research assistant analyzed data using the grounded theory approach (including open coding, constant comparison, and axial coding), which resulted in the emergence of seven major themes. Themes consistent with prior research include (1) bridging the gap between military and civilian life, (2) rebuilding a support system outside of the military, (3) readapting to the culture of civilian life, and (4) finding meaning in a new life perspective and purpose. Themes not indicated in previous research are (5) battling the stereotypes, (6) taming the fight-or-flight response, and (7) attitudes about mental illness carry over to civilian life. Based on the results of this review, recommendations are given for college campuses to support veterans in transition