Controlled Population of Floquet-Bloch States via Coupling to Bose and Fermi Baths

External driving is emerging as a promising tool for exploring new phases in quantum systems. The intrinsically non-equilibrium states that result, however, are challenging to describe and control. We study the steady states of a periodically driven one-dimensional electronic system, including the effects of radiative recombination, electron-phonon interactions, and the coupling to an external fermionic reservoir. Using a kinetic equation for the populations of the Floquet eigenstates, we show that the steady-state distribution can be controlled using the momentum and energy relaxation pathways provided by the coupling to phonon and Fermi reservoirs. In order to utilize the latter, we propose to couple the system and reservoir via an energy filter which suppresses photon-assisted tunneling. Importantly, coupling to these reservoirs yields a steady state resembling a band insulator in the Floquet basis. The system exhibits incompressible behavior, while hosting a small density of excitations. We discuss transport signatures, and describe the regimes where insulating behavior is obtained. Our results give promise for realizing Floquet topological insulators.Comment: 24 pages, 7 figures; with appendice

Affective Politics and Technology Buy-In: A Framework of Social, Political, and Fantasmatic Logics

We propose a socially informed explanation of technology framing by examining technology “buy-in”—actors’ relative susceptibility to such framing. We draw on the field of critical social theory to introduce the “Logics,” a new framework to the IS discipline that reveals a performative relationship between collective framing, power, and affect. The Logics enable us to study buy-in by revealing the differing degrees of affective self-identification that underpin and color social practices, showing their inherently political nature. We exemplify the affective as well as social politics of buy-in with an account of Unity 3D, a market-leading game engine that underwent a major repositioning from “fringe” to “mainstream” markets, and discuss four poles of affective positioning with which to conceptualize technology buy-in. We conclude by highlighting the consequent need for greater political and ethical awareness about the framing of IS and by proposing a framework for conceptualizing actors’ orientations toward and thus possible buy-in or resistance to technology framing

Precautionary Wealth Accumulation: A Positive Third Derivative is not Enough

It is commonly conjectured that expected wealth accumulation increases when earnings risk increases as long as the utility function in each period is increasing, concave and has a positive third derivative. We present a counter example which highlights the importance of the convexity of the savings function.

The Immune Response to Herpes Simplex Virus Type 1 Infection in Susceptible Mice is a Major Cause of CNS Pathology Resulting in Fatal Encephalitis

This study was undertaken to investigate possible immune mechanisms in fatal HSV-1 encephalitis (HSE) after HSV-1 corneal inoculation. Susceptible 129S6 (129) but not resistant C57BL/6 (B6) mice developed intense focal inflammatory brainstem lesions of primarily F4/80+ macrophages and Gr-1+ neutrophils detectable by MRI as early as day 6 post infection (PI). Depletion of macrophages and neutrophils significantly enhanced survival of infected 129 mice. Immunodeficient B6 (IL-7R-/-Kitw41/w41) mice lacking adaptive cells (B6-E mice) transplanted with 129 bone marrow showed significantly accelerated fatal HSE compared to B6-E mice transplanted with B6 marrow or control non-transplanted B6-E mice. In contrast, there was no difference in ocular viral shedding in B6-E mice transplanted with 129 bone marrow or B6 bone marrow. Acyclovir treatment of 129 mice beginning day 4 PI (24 h after HSV-1 first reaches the brain stem) reduced nervous system viral titers to undetectable levels but did not alter brainstem inflammation or mortality. We conclude that fatal HSE in 129 mice results from widespread damage in the brainstem caused by destructive inflammatory responses initiated early in infection by massive infiltration of innate cells

Autotransporters and Their Role in the Virulence of Burkholderia pseudomallei and Burkholderia mallei

Burkholderia pseudomallei and Burkholderia mallei are closely related Gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. Autotransporters (ATs) comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases, and actin-nucleating factors. The B. pseudomallei K96243 genome contains 11 predicted ATs, eight of which share homologs in the B. mallei ATCC 23344 genome. This review distils key findings from in silico, in vitro, and in vivo studies on the ATs of B. pseudomallei and B. mallei. To date, the best characterized of the predicted ATs of B. pseudomallei and B. mallei is BimA, a predicted trimeric AT mediating actin-based motility which varies in sequence and mode of action between Burkholderia species. Of the remaining eight predicted B. pseudomallei trimeric autotransporters, five of which are also present in B. mallei, two (BoaA and BoaB), have been implicated in bacterial adhesion to epithelial cells. Several predicted Burkholderia ATs are recognized by human humoral and cell-mediated immunity, indicating that they are expressed during infection and may be useful for diagnosis and vaccine-mediated protection. Further studies on the mode of secretion and functions of Burkholderia ATs will facilitate the rational design of control strategies

Steady state of interacting Floquet insulators

Floquet engineering offers tantalizing opportunities for controlling the dynamics of quantum many-body systems and realizing new nonequilibrium phases of matter. However, this approach faces a major challenge: generic interacting Floquet systems absorb energy from the drive, leading to uncontrolled heating which washes away the sought-after behavior. How to achieve and control a nontrivial nonequilibrium steady state is therefore of crucial importance. In this work, we study the dynamics of an interacting one-dimensional periodically driven electronic system coupled to a phonon heat bath. Using the Floquet-Boltzmann equation (FBE) we show that the electronic populations of the Floquet eigenstates can be controlled by the dissipation. We find the regime in which the steady state features an insulator-like filling of the Floquet bands, with a low density of additional excitations. Furthermore, we develop a simple rate equation model for the steady state excitation density that captures the behavior obtained from the numerical solution of the FBE over a wide range of parameters

Design Guidelines for High-Performance SCM Hierarchies

With emerging storage-class memory (SCM) nearing commercialization, there is evidence that it will deliver the much-anticipated high density and access latencies within only a few factors of DRAM. Nevertheless, the latency-sensitive nature of memory-resident services makes seamless integration of SCM in servers questionable. In this paper, we ask the question of how best to introduce SCM for such servers to improve overall performance/cost over existing DRAM-only architectures. We first show that even with the most optimistic latency projections for SCM, the higher memory access latency results in prohibitive performance degradation. However, we find that deployment of a modestly sized high-bandwidth 3D stacked DRAM cache makes the performance of an SCM-mostly memory system competitive. The high degree of spatial locality that memory-resident services exhibit not only simplifies the DRAM cache's design as page-based, but also enables the amortization of increased SCM access latencies and the mitigation of SCM's read/write latency disparity. We identify the set of memory hierarchy design parameters that plays a key role in the performance and cost of a memory system combining an SCM technology and a 3D stacked DRAM cache. We then introduce a methodology to drive provisioning for each of these design parameters under a target performance/cost goal. Finally, we use our methodology to derive concrete results for specific SCM technologies. With PCM as a case study, we show that a two bits/cell technology hits the performance/cost sweet spot, reducing the memory subsystem cost by 40% while keeping performance within 3% of the best performing DRAM-only system, whereas single-level and triple-level cell organizations are impractical for use as memory replacements.Comment: Published at MEMSYS'1

First Report of NRG Oncology/Radiation Therapy Oncology Group 0622: A Phase 2 Trial of Samarium-153 Followed by Salvage Prostatic Fossa Irradiation in High-Risk Clinically Nonmetastatic Prostate Cancer After Radical Prostatectomy.

PURPOSE: To investigate the utility of 153Sm lexidronam (Quadramet) in the setting of men with prostate cancer status post radical prostatectomy who develop biochemical failure with no clinical evidence of osseous metastases. PATIENTS AND METHODS: Trial NRG Oncology RTOG 0622 is a single-arm phase 2 trial that enrolled men with pT2-T4, N0-1, M0 prostate cancer status post radical prostatectomy, who meet at least 1 of these biochemical failure criteria: (1) prostate-specific antigen (PSA) \u3e 1.0 ng/mL; (2) PSA \u3e 0.2 ng/mL if Gleason score 9 to 10; or (3) PSA \u3e 0.2 ng/mL if N1. Patients received 153Sm (2.0 mCi/kg intravenously × 1) followed by salvage external beam radiation therapy (EBRT) to the prostatic fossa (64.8-70.2 Gy in 1.8-Gy daily fractions). No androgen deprivation therapy was allowed. The primary objective was PSA response within 12 weeks of receiving 153Sm. The secondary objectives were to: (1) assess the completion rate for the regimen of 153Sm and EBRT; (2) evaluate the hematologic toxicity and other adverse events (AEs) at 12 and 24 weeks; and (3) determine the freedom from progression rate at 2 years. RESULTS: A total of 60 enrolled eligible patients were included in this analysis. Median follow-up was 3.97 years. A PSA response was achieved in 7 of 52 evaluable patients (13.5%), compared with the 25% hypothesized. The 2-year freedom from progression rate was 25.5% (95% confidence interval 14.4%-36.7%), and the biochemical failure rate was 64.4% (95% CI 50.5%-75.2%). Samarium-153 was well tolerated, with 16 (of 60) grade 3 to 4 hematologic AEs and no grade 5 hematologic AEs. Radiation therapy was also well tolerated, with no grade 3 to 5 acute radiation therapy-related AEs and 1 grade 3 to 4 and no grade 5 late radiation therapy-related AEs. CONCLUSIONS: Trial NRG Oncology RTOG 0622 did not meet its primary endpoint of PSA response, although the regimen of 153Sm and salvage EBRT was well tolerated. Although the toxicity profile supports study of 153Sm in high-risk disease, it may not be beneficial in men receiving EBRT

The effects of fatigue on robotic surgical skill training in Urology residents

This study reports on the effect of fatigue on Urology residents using the daVinci surgical skills simulator (dVSS). Seven Urology residents performed a series of selected exercises on the dVSS while pre-call and post-call. Prior to dVSS performance a survey of subjective fatigue was taken and residents were tested with the Epworth Sleepiness Scale (ESS). Using the metrics available in the dVSS software, the performance of each resident was evaluated. The Urology residents slept an average of 4.07 h (range 2.5-6 h) while on call compared to an average of 5.43 h while not on call (range 3-7 h, p = 0.08). Post-call residents were significantly more likely to be identified as fatigued by the Epworth Sleepiness Score than pre-call residents (p = 0.01). Significant differences were observed in fatigued residents performing the exercises, Tubes and Match Board 2 (p = 0.05, 0.02). Additionally, there were significant differences in the total number of critical errors during the training session (9.29 vs. 3.14, p = 0.04). Fatigue in post-call Urology residents leads to poorer performance on the dVSS simulator. The dVSS may become a useful instrument in the education of fatigued residents and a tool to identify fatigue in trainees

Transperitoneal Robotic-Assisted Laparoscopic Prostatectomy After Prosthetic Mesh Herniorrhaphy

BACKGROUND AND OBJECTIVES: We report our institutional experience performing transperitoneal robotic-assisted laparoscopic prostatectomy (RALP) in patients with prior prosthetic mesh herniorrhaphy to assess the feasibility of this procedure in this patient population. METHODS: From October 2005 to January 2008, transperitoneal robotic-assisted laparoscopic prostatectomies were performed and prospectively recorded. We retrospectively reviewed 309 patients. RESULTS: Twenty-seven patients (8.7%) were found to have a history of prior hernia repair with prosthetic mesh placement. The mean age was 55.7, estimated blood loss (EBL) was 228 mL, operative (console) time was 197 minutes, and length of hospital stay (LOS) was 1.62 days. In contrast, patients undergoing RALP with no history of mesh herniorrhaphy had a mean age of 59.3, EBL of 302 mL, console time of 193 minutes, and LOS of 2.2 days. These differences were not statistically significant. The mesh herniorrhaphy cohort had a lower percentage of organ-confined disease, but no difference was seen in margin status, continence, or potency rates after one year. CONCLUSIONS: Transperitoneal RALP is a feasible option for previously operated on patients with prosthetic mesh herniorrhaphy. Two areas that we identified as critical were the initial step of gaining access for pneumoperitoneum and port placement, and meticulous dissection to expose the mesh, which can be subsequently avoided and left intact. As RALP continues to gain popularity, urologists will continue to exploit the advantages of robotic surgery to perform increasingly challenging cases