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Full-Text Articles in Physical Sciences and Mathematics

Modern Spectral Climate Patterns In Rhythmically Deposited Argillites Of The Gowganda Formation (Early Proterozoic), Southern Ontario, Canada, Gary B. Hughes, Robert Giegengack, Haralambos N. Kritikos Aug 2009

Modern Spectral Climate Patterns In Rhythmically Deposited Argillites Of The Gowganda Formation (Early Proterozoic), Southern Ontario, Canada, Gary B. Hughes, Robert Giegengack, Haralambos N. Kritikos

Gary B. Hughes

Rhythmically deposited argillites of the Gowganda Formation (ca. 2.0–2.5 Ga) probably formed in a glacial setting. Drop stones and layered sedimentary couplets in the rock presumably indicate formation in a lacustrine environment with repeating freeze–thaw cycles. It is plausible that temporal variations in the thickness of sedimentary layers are related to interannual climatic variability, e.g. average seasonal temperature could have influenced melting and the amount of sediment source material carried to the lake. A sequence of layer couplet thickness measurements was made from high-resolution digitized photographs taken at an outcrop in southern Ontario, Canada. The frequency spectrum of thickness measurements …


Correction To “The Theory Of Quaternion Orthogonal Designs”, Tadeusz Wysocki, Beata Wysocki, Sarah Spence Adams Jul 2009

Correction To “The Theory Of Quaternion Orthogonal Designs”, Tadeusz Wysocki, Beata Wysocki, Sarah Spence Adams

Sarah Spence Adams

Seberry et al. claimed that even though the dual-polarized transmission channel cannot be considered as described by means of a single quaternionic gain, the maximum-likelihood (ML) decoding rule can be decoupled for orthogonal space–time-polarization block codes (OSTPBCs) derived from quaternion orthogonal designs (QODs) [1, Sec. IV]. Regretfully, a correction is necessary, and we will show that decoupled decoding using the method presented therein is only optimal for codes derived from certain QODs, not from arbitrary QODs as previously suggested.


Balancing The R With The E In Reu Programs, Sarah Spence Adams, Rick Gillman, Darren Narayan Dec 2008

Balancing The R With The E In Reu Programs, Sarah Spence Adams, Rick Gillman, Darren Narayan

Sarah Spence Adams

Externally or internally funded Research Experience for Undergraduates (REU) programs offer students the opportunity to work with faculty on unsolved problems and can serve as a highlight of their undergraduate career. The overall goal of these formative programs is that students and faculty have an enjoyable experience as they investigate the horizon of knowledge. However, there is a question on how much a program should focus on research and how much emphasis should be placed on the experience. In the end, both aspects should be given considerable weight.


Target Finding Time For Microtubules In A Confined Geometry, Mitra Shojania-Feizabadi Dec 2008

Target Finding Time For Microtubules In A Confined Geometry, Mitra Shojania-Feizabadi

Mitra Shojania-Feizabadi

Dynamic instability of microtubules may reach the steady state with exponentially growing or decaying length distribution in a confined geometry such as a cell-like environment. In this brief communication, the target finding time for these microtubules with the stochastic polymerization in a confined geometry is compared with the reversible polymerization. It is shown that the efficiency of microtubules with increasing length distribution at the steady state depends on the location of a target. They are very efficient in finding a target located at the cell cortex, which confirms the significant biological role they play in rapidly reaching the cell cortex …


What Does It Mean To Be A Science Librarian 2.0?, Melissa J. Harvey Dec 2008

What Does It Mean To Be A Science Librarian 2.0?, Melissa J. Harvey

Missy Harvey

Science librarians, as well as other librarians, have seen ample new technologies come and go over the years. Librarians experiment and try to find ways to employ the new tools in our libraries. A driving force in our decision making about what tools to use should always be our patrons and whether the tools can help us do a better job of delivering services. This paper discusses what technologies have proven to be successful, as well as other thoughts to bear in mind as librarians evaluate Web 2.0 tools for science libraries.


Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer Dec 2008

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …