The twins
or clock paradox has been a subject of lively discussion and occasional disagreement
among both relativists and the public for over 100 years, and continues to attract
physicists who write papers giving new analyses or defending old ones, even though
many physicists now consider the matter only of educational interest. This paper
investigates the number of papers, which is increasing, and trends in explanations,
some of which are now targeted at professional physicists and other of which are
targeted at optical or radar visualization rather than problem solving. Observations
of students indicate that the latest techniques help but only somewhat. An analysis
is made of 21 previous treatments appearing in the education related American Journal
of Physics, Einstein’s discussions and several other pedagogical papers. A new memory
aid for simultaneity transformation is given that puts it on a par with “time dilation”
and “length contraction” for quick and easy problem visualization. The point of
view of a trailing twin is introduced to show how simultaneity changes account for
missing time in the turnaround. Length contraction is treated on equal footing with
time dilation, and Swann’s insight into clocks is extended to lengths. Treatments
using the conventionality of simultaneity are seen as equivalent to choice of co-moving
frames. Responses to difficult questions are suggested which avoid being dismissive,
and engage students’ critical thinking.

A general theory of inertia tends to be circular because momentum and therefore inertia are taken as assumptions in quantum field theories. In this paper we explore instead using position uncertainty to infer inertia with mediation by quasi-measurement interactions. This method avoids attachment to the reference frame of the source masses and is thus completely relativistic, overcoming a conflict between historical theories of inertia and relativity. We investigate what laws of motion result, and whether natural explanations for equivalence and dark energy emerge.

Abstract:
Using security incident history we identify threats to and using the IoT and other ubiquitous devices emerging since 2012, gaining widespread recognition in 2016, and only lightly addressed in either IoT security literature or the press. We show the IoT has likely already been used in cyber war between major powers. The new threats, most notably “hijack,” are larger than previous threats combined, but only mildly affect suppliers, and only a few clients. Using a successful behavioral-economic model we show that traditional mitigation places responsibility on un-affected parties and likely will not work. For suppliers, there are profit-conflicted motives, as the new threat rides on a profit vehicle. The new threat circumvents conventional security architecture at a behavioral level. We analyze each actor-target pair and evaluate technical strategies. More effective technical strategies are suggested where old ones are overmatched by the budgets, technical prowess or regulatory power of hostile actors, or the technical nature of the threats. Consolidated action may be needed, but regulation is difficult because of conflicts of interest within the national security community.

Abstract:
This is the first of two lectures on a new powerful technique employed by Brown, Preston, and Singleton (BPS) to calculate transport quantities in a plasma. This exposition will be self-contained and intended for those who are not specialists in quantum field theory, where the technique of dimensional continuation exploited by BPS first arose. The method is highlighted by the interesting analogy between the Coulomb logarithm of Lyman Spitzer on the one hand, and the Lamb shift as calculated by Hans Bethe on the other. BPS employed the method in a novel way that provides the leading and subleading behavior for processes with competing disparate length or energy scales. They calculated the temperature equilibration rate to leading and next-to-leading order in the plasma number density for any two species in a plasma that are in thermal equilibrium with themselves, but not necessarily with each other. A special case of this calculation is the electron-ion temperature equilibration rate. It should be emphasized that the BPS result is not a model, but rather it is an exact calculation of the leading terms in a well-defined perturbation theory. This exact result differs from approximations and models given in the literature.

Abstract:
The effective management of chronic pain remains enigmatic. There is a paucity of effective mechanistically-based approaches employed. Chronic visceral pain is a particularly difficult subcategory to manage. Glutamate is the most predominant excitatory neurotransmitter and mediates many aspects of sensory function including acute and chronic pain. There is a growing literature describing the efficacy of physiologically dominant glutamate transporter GLT-1 up-regulation in attenuating chronic visceral and somatic nociception. Since glutamate is the major excitatory neurotransmitter released in the first central synapse of the pain-transmitting afferent neurons, augmentation of GLT-1 activity, which reduces extracellular levels of glutamate, may be an important target for pain management strategies. This review summarizes studies in our laboratory and others which highlight findings that GLT-1 up-regulation by transgenic, pharmacologic and viral transfection approaches attenuate a host of nociceptive responses emanating from visceral or somatic sources in animal models. The study also outlines the future work that will be required to ascertain the translational potential of this approach.

Abstract:
A completely rigorous first-principles calculation of the charged particle stopping power has recently been performed by Brown, Preston, and Singleton (BPS). This calculation is exact to leading and next-to-leading order in the plasma number density, including an exact treatment of two-body quantum scattering. The BPS calculation is therefore extremely accurate in the plasma regime realized during the ignition and burn of an inertial confinement fusion capsule. For deuterium-tritium fusion, the 3.5 MeV alpha particle range tends to be 20-30% longer than most models in the literature have predicted, and the energy deposition into the ions tends to be smaller. Preliminary numerical simulations indicate that this increases the rho-R required to achieve ignition.

Abstract:
This is the second in a series of two lectures on the technique of dimensional continuation, a new method for analytically calculating certain energy transport quantities in a weakly to moderately coupled plasma. Recently, this method was employed by Brown, Preston, and Singleton (BPS) to calculate the electron-ion temperature equilibration rate and the charged particle stopping power to leading and next-to-leading order in the plasma coupling. In this lecture, I develop the framework further, and then explicitly calculate the electron-ion temperature equilibration rate in the high temperature limit. This method captures all short and long distance physics to second order in the plasma coupling. This analytic perturbative technique is applicable for ignition in inertial confinement fusion and for other processes in hot a weakly coupled plasma.

Abstract:
I will discuss a new method for calculating transport quantities, such as the charged particle stopping power, in a weakly to moderately coupled plasma. This method, called dimensional continuation, lies within the framework of convergent kinetic equations, and it is powerful enough to allow for systematic perturbative expansions in the plasma coupling constant. In particular, it provides an exact evaluation of the stopping power to leading and next-to-leading order in the plasma coupling, with the systematic error being of cubic order. Consequently, the calculation is near-exact for a weakly coupled plasma, and quite accurate for a moderately coupled plasma. The leading order term in this expansion has been known since the classic work of Spitzer. In contrast, the next-to-leading order term has been calculated only recently by Brown, Preston, and Singleton (BPS), using the aforementioned method, to account for all short- and long-distance physics accurate to second order in the plasma coupling, including an exact treatment of the quantum-to-classical scattering transition. Preliminary numerical studies suggest that the BPS stopping power increases the ignition threshold, thereby having potential adverse implications for upcoming high energy density facilities. Since the key ideas behind the BPS calculation are possibly unfamiliar to plasma physicists, and the implications might be important, I will use this opportunity to explain the method in a pedagogical fashion.

Abstract:
This is the first of two lectures on a new powerful technique employed by Brown, Preston, and Singleton (BPS) to calculate transport quantities in a plasma. This exposition will be self-contained and intended for those who are not specialists in quantum field theory, where the technique of dimensional continuation exploited by BPS first arose. The method is highlighted by the interesting analogy between the Coulomb logarithm of Lyman Spitzer on the one hand, and the Lamb shift as calculated by Hans Bethe on the other. BPS employed the method in a novel way that provides the leading and subleading behavior for processes with competing disparate length or energy scales. They calculated the temperature equilibration rate to leading and next-to-leading order in the plasma number density for any two species in a plasma that are in thermal equilibrium with themselves, but not necessarily with each other. A special case of this calculation is the electron-ion temperature equilibration rate. It should be emphasized that the BPS result is not a model, but rather it is an exact calculation of the leading terms in a well-defined perturbation theory. This exact result differs from approximations and models given in the literature.

Abstract:
We study the sublattices of the rank $2^d$ Barnes-Wall lattices $\bw d$ which occur as fixed points of involutions. They have ranks $2^{d-1}$ (for dirty involutions) or $2^{d-1}\pm 2^{k-1}$ (for clean involutions), where $k$, the defect, is an integer at most $\frac d 2$. We discuss the involutions on $\bw d$ and determine the isometry groups of the fixed point sublattices for all involutions of defect 1. Transitivity results for the Bolt-Room-Wall group on isometry types of sublattices extend those in \cite{bwy}. Along the way, we classify the orbits of $AGL(d,2)$ on the Reed-Muller codes $RM(2,d)$ and describe {\it cubi sequences} for short codewords, which give them as Boolean sums of codimension 2 affine subspaces.