When America Fights: The Uses of U.S. Military Force

“Timing is everything,” so the saying goes. Timing was certainly a factor in de- veloping a fair and reasoned review for this book; it arrived in this reviewer’s mailbox on 12 September 2001. Since the major thesis of Donald Snow’s concise and cogent work is that peacekeeping will be the most likely type of early twenty-first century military operation for the United States, the book initially appeared quaint and somewhat nostalgic: how nice and simple it would be to deal with questions of how to bring and sus- tain peace to other lands

Isospin of new physics in ∣ΔS∣=1|\Delta S|=1 charmless B decays

New physics (NP) in charmless strangeness-changing $B$ and $B_s$ decays, which are dominated by the $b \to s$ penguin amplitudes, can either preserve isospin or change it by one unit. A general formalism is presented studying pairs of processes related to each other by isospin reflection. We discuss information on $\Delta I$ in NP amplitudes, provided by time-integrated CP-violating rate asymmetries in $B^+$ and $B^0$ decays (or in $B_s$ decays), differences between rates for isospin-reflected processes, and coefficients $S$ of $\sin \Delta m t$ in time-dependent CP asymmetries. These four asymmetries in $B^+$ and $B^0$ decays (or five asymmetries in $B_s$ decays) are shown to determine the magnitude and CP-violating phase of a potential isovector NP amplitude, and the imaginary part of an isoscalar amplitude, assuming that strong phases in NP amplitudes are negligible. This information may be compared with predictions of specific models, for which we discuss a few examples.Comment: 22 pages, to be published in Phys. Rev.

Two-Body Cabibbo-Suppressed Charmed Meson Decays

Singly-Cabibbo-suppressed decays of charmed particles governed by the quark subprocesses $c \to s u \bar s$ and $c \to d u \bar d$ are analyzed using a flavor-topology approach, based on a previous analysis of the Cabibbo-favored decays governed by $c \to s u \bar d$. Decays to $PP$ and $PV$, where $P$ is a pseudoscalar meson and $V$ is a vector meson, are considered. We include processes in which $\eta$ and $\eta '$ are produced.Comment: 18 pages, latex, 2 figures, to be submitted to Phys. Rev.

Supersymmetric Relations Among Electromagnetic Dipole Operators

Supersymmetric contributions to all leptonic electromagnetic dipole operators have essentially identical diagramatic structure. With approximate slepton universality this allows the muon anomalous magnetic moment to be related to the electron electric dipole moment in terms of supersymmetric phases, and to radiative flavor changing lepton decays in terms of small violations of slepton universality. If the current discrepancy between the measured and Standard Model values of the muon anomalous magnetic moment is due to supersymmetry, the current bound on the electron electric dipole moment then implies that the phase of the electric dipole operator is less than $2 \times 10^{-3}$. Likewise the current bound on $\mu \to e \gamma$ decay implies that the fractional selectron-smuon mixing in the left-left mass squared matrix, \delta m_{\smuon \selectron}^2 / m_{\slepton}^2, is less than $10^{-4}$. These relations and constraints are fairly insensitive to details of the superpartner spectrum for moderate to large $\tan \beta$.Comment: Latex, 38 pages, 2 figure

Joint Goal and Strategy Inference across Heterogeneous Demonstrators via Reward Network Distillation

Reinforcement learning (RL) has achieved tremendous success as a general framework for learning how to make decisions. However, this success relies on the interactive hand-tuning of a reward function by RL experts. On the other hand, inverse reinforcement learning (IRL) seeks to learn a reward function from readily-obtained human demonstrations. Yet, IRL suffers from two major limitations: 1) reward ambiguity - there are an infinite number of possible reward functions that could explain an expert's demonstration and 2) heterogeneity - human experts adopt varying strategies and preferences, which makes learning from multiple demonstrators difficult due to the common assumption that demonstrators seeks to maximize the same reward. In this work, we propose a method to jointly infer a task goal and humans' strategic preferences via network distillation. This approach enables us to distill a robust task reward (addressing reward ambiguity) and to model each strategy's objective (handling heterogeneity). We demonstrate our algorithm can better recover task reward and strategy rewards and imitate the strategies in two simulated tasks and a real-world table tennis task.Comment: In Proceedings of the 2020 ACM/IEEE In-ternational Conference on Human-Robot Interaction (HRI '20), March 23 to 26, 2020, Cambridge, United Kingdom.ACM, New York, NY, USA, 10 page

Eukaryotic Flagella: Variations in Form, Function, and Composition during Evolution

The microtubule axoneme is an iconic structure in eukaryotic cell biology and the defining structure in all eukaryotic flagella (or cilia). Flagella occur in taxa spanning the breadth of eukaryotic evolution, which indicates that the organelle's origin predates the radiation of extant eukaryotes from a last common ancestor. During evolution, the flagellar architecture has been subject to both elaboration and moderation. Even conservation of 9+2 architecture—the classic microtubule configuration seen in most axonemes—belies surprising variation in protein content. Classically considered as organelles of motility that support cell swimming or fast movement of material across a cell surface, it is now clear that the functions of flagella are also far broader; for instance, the involvement of flagella in sensory perception and protein secretion has recently been made evident in both protists and animals. Here, we review and discuss, in an evolutionary context, recent advances in our understanding of flagellum function and composition

Cutaneous Head and Neck Squamous Cell Carcinoma with Regional Metastases: The Prognostic Importance of Soft Tissue Metastases and Extranodal Spread

Extranodal spread (ENS) is an established adverse prognostic factor in metastatic cutaneous squamous cell carcinoma (cSCC); however, the clinical significance of soft tissue metastases (STM) is unknown. The aim of this study was to evaluate the prognosis of patients with STM from head and neck cSCC, and to compare this with that of node metastases with and without ENS. Patients with cSCC metastatic to the parotid and/or neck treated by primary surgical resection between 1987 and 2007 were included. Metastatic nodes > 3 cm in size were an exclusion criterion. A Cox proportional hazard model was used to determine the effect of STM adjusting for other relevant prognostic factors. The population included 164 patients with a median follow-up of 26 months. There were 8 distant and 37 regional recurrences. There were 22 were cancer-specific deaths, and 29 patients died. STM was a significant predictor of reduced overall (hazard ratio 3.3; 95% confidence interval 1.6-6.4; P = 0.001) and disease-free survival (hazard ratio 2.4; 95% confidence interval 1.4-4.1; P = 0.001) when compared to patients with node disease with or without ENS. After adjusting for covariates, STM and number of involved nodes were significant independent predictors of overall and disease-free survival. In metastatic cSCC of the head and neck, the presence of STM is an independent predictor of reduced survival and is associated with a greater adverse effect than ENS alone