Discussion of: A statistical analysis of multiple temperature proxies: Are reconstructions of surface temperatures over the last 1000 years reliable?

McShane and Wyner [(2011); hereinafter MW11] reiterate a well-known and central challenge of paleoclimatology: it is fraught with uncertainties and based on noisy observations. Decades of research have aimed at characterizing these uncertainties and interpreting proxies through laboratory experiments, field observations, theory, process-based modeling, cross-record comparisons, and indeed through statistical modeling and hypothesis testing. It is against this larger backdrop that the problem addressed by MW11 must be considered. Attempts to reconstruct global or hemispheric temperature indices and fields using multi-proxy networks are an outgrowth of many efforts in paleoclimatology, but represent relatively recent pursuits in the field. They provide neither the principal scientific evidence supporting climate-proxy connections, nor the most compelling, and the inference by MW11 that their own findings demonstrate a widespread failure in the predictive capacity of climate proxies is at odds with most other independent lines of proxy research

Surface study of the (100) and (010) faces of the quasicrystalapproximant Al4(Cr, Fe)

Low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) results are used to study the pseudo-6-fold nature of the (100) surface of the orthorhombic quasicrystal approximant Al4(Cr, Fe). LEED patterns are also presented from the pseudo-10-fold (010) surface of this material. In each case the results are compared with the known bulk structure of this complex metallic alloy

Axon Initial Segment Plasticity in Mouse Models of Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a debilitating and fatal neurodegenerative disease affecting upper and lower motor neurons. Though studied for over two decades since the first ALS-associated genetic mutation was discovered, researchers have yet to uncover the pathological processes that lead to progressive degeneration of motor neurons in ALS, or to develop effective treatments. One prominent hypothesis proposes that excitotoxicity caused by increased motor neuron firing plays a role in ALS pathogenesis. While prior studies reported increased action potential firing in early postnatal ALS-model motor neurons in vivo, it remains unknown whether the increased activity stems from increased intrinsic excitability of ALS motor neurons or from increased excitatory drive, and whether these changes are transient or persist into adulthood, when ALS symptoms emerge. In this thesis, I circumvented the difficulties in standard measurement of electrophysiological properties of adult spinal motor neurons in vivo by relying on the visualization of the axon initial segment, a subcellular structure known to undergo compensatory structural changes in response to perturbations in excitatory input. I discovered that cultured motor neurons derived from stem cells of the SOD1G93A mouse model of ALS display shortened axon initial segments and hypoexcitable electrophysiological properties. The shortening of the axon initial segment is compensatory, as ALS motor neurons receive increased numbers of excitatory inputs and manifest increased spontaneous activity. Remarkably, similar shortening of the axon initial segment was detected in early presymptomatic spinal motor neurons in vivo. The shortened axon initial segment persists into the symptomatic stages and is particularly pronounced in motor neurons containing p62 immunoreactive aggregates and neurons exhibiting swollen mitochondria, two signs of stress and neurodegeneration in the disease. Based on these observations I propose that early in the presymptomatic stages of the disease, spinal motor neurons recruit excessive excitatory inputs, resulting in their increased activity that is in part compensated by shortening of the axon initial segment. This state persists and becomes even more pronounced in motor neurons exhibiting biochemical changes preceding neurodegeneration. While these observations support the potential role for excitotoxic stress in spinal ALS motor neurons, I paradoxically observed the opposite phenotype in ALS-vulnerable cranial motor neurons in the brainstem of the SOD1G93A animals, raising the possibility that the cellular stress that drives the neurodegeneration in ALS is motor neuron subtype specific

A Proposal for the Inclusion of Jazz Theory Topics in the Undergraduate Music Theory Curriculum

The demands of the twenty-first century require musicians to be more stylistically versatile since there are more opportunities for performance when musicians are familiar with not only classical but also jazz and popular music. Understanding the theory behind jazz and pop styles will help prepare the musicians for these opportunities. Since all music students take music theory, it is in the students’ best interest for teachers of theory to include jazz theory topics in the classical music theory curriculum. The purpose of this thesis is to propose the inclusion of jazz theory topics in the undergraduate music theory curriculum. To show how jazz theory can be incorporated into the theory curriculum, this thesis provides an example section of a theory textbook on the topic of chord-scale theory

Simulating heat transport of harmonic temperature signals in the Earth's shallow subsurface: Lower-boundary sensitivities

We assess the sensitivity of a subsurface thermodynamic model to the depth of its lower-boundary condition. Analytic solutions to the one-dimensional thermal diffusion equation demonstrate that boundary conditions imposed at shallow depths (2-20 m) corrupt the amplitudes and phases of propagating temperature signals. The presented solutions are for: 1) a homogeneous infinite half-space driven by a harmonic surface-temperature boundary condition, and 2) a homogeneous slab with a harmonic surface-temperature boundary condition and zero-flux lower-boundary condition. Differences between the amplitudes and phases of the two solutions range from 0 to almost 100%, depending on depth, frequency and subsurface thermophysical properties. The implications of our results are straightforward: the corruption of subsurface temperatures can affect model assessments of soil microbial activity, vegetation changes, freeze-thaw cycles, and hydrologic dynamics. It is uncertain, however, whether the reported effects will have large enough impacts on land-atmosphere fluxes of water and energy to affect atmospheric simulations

Pacific Ocean Forcing and Atmospheric Variability are the Dominant Causes of Spatially Widespread Droughts in the Contiguous United States

The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan-CONUS droughts) are investigated using 16-member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856 to 2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan-CONUS droughts. Model results show that SST forcing of pan-CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Nia conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan-CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan-CONUS droughts by establishing a dominant high centered over the US montane West. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model-inferred contributions to pan-CONUS droughts from La Nias and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan-CONUS. The ambiguity thus opens the possibility that the observational results are limited by sampling over the 20th-century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles

C60 adsorption on an aperiodically modulated Cu surface

Copper deposited on the ve-fold surface of icosahedral Al-Pd-Mn forms domains of a structure whose surface has a one-dimensional aperiodic modulation. It is shown that C60 deposited on this aperiodic film has highly reduced mobility as compared to C60 deposited on periodic Cu surfaces. This fnding is explained in terms of the recently proposed structural model of this system