Hidden Conformal Invariance of Scalar Effective Field Theories

We argue that conformal invariance is a common thread linking several scalar effective field theories that appear in the double copy and scattering equations. For a derivatively coupled scalar with a quartic ${\cal O}(p^4)$ vertex, classical conformal invariance dictates an infinite tower of additional interactions that coincide exactly with Dirac-Born-Infeld theory analytically continued to spacetime dimension $D=0$. For the case of a quartic ${\cal O}(p^6)$ vertex, classical conformal invariance constrains the theory to be the special Galileon in $D=-2$ dimensions. We also verify the conformal invariance of these theories by showing that their amplitudes are uniquely fixed by the conformal Ward identities. In these theories, conformal invariance is a much more stringent constraint than scale invariance.Comment: 7 page

First Principles Derivation of Effective Ginzburg-Landau Free Energy models for Crystalline Systems

The expression of the free energy density of a classical crystalline system as a gradient expansion in terms of a set of order parameters is developed using classical density functional theory. The goal here is to extend and complete an earlier derivation by L{\"o}wen et al (Europhys. Lett.9, 791, 1989). The limitations of the resulting expressions are also discussed including the boundary conditions needed for finite systems and the fact that the results cannot, at present, be used to take into account elastic relaxation.Comment: 12 pages, no figures, sumitted to Physica

Cost of HPV screening at community health campaigns (CHCs) and health clinics in rural Kenya.

BACKGROUND:Cervical cancer is the most frequent neoplasm among Kenyan women, with 4800 diagnoses and 2400 deaths per year. One reason is an extremely low rate of screening through pap smears, at 13.8% in 2014. Knowing the costs of screening will help planners and policymakers design, implement, and scale programs. METHODS:We conducted HPV-based cervical cancer screening via self-collection in 12 communities in rural Migori County, Kenya. Six communities were randomized to community health campaigns (CHCs), and six to screening at government clinics. All HPV-positive women were referred for cryotherapy at Migori County Hospital. We prospectively estimated direct costs from the health system perspective, using micro-costing methods. Cost data were extracted from expenditure records, staff interviews, and time and motion logs. Total costs per woman screening included three activities: outreach, HPV-based screening, and notification. Types of inputs include personnel, recurrent goods, capital goods, and services. We costed potential changes to implementation for scaling. RESULTS:From January to September 2016, 2899 women were screened in CHCs and 2042 in clinics. Each CHC lasted for 30 working days, 10 days each for outreach, screening, and notification. The mean cost per woman screened was $25.00 for CHCs [median:$25.09; Range: $22.06-30.21] and$29.56 for clinics [$28.90;$25.27-37.08]. Clinics had higher costs than CHCs for personnel ($14.27 vs.$11.26) and capital ($5.55 vs.$2.80). Screening costs were higher for clinics at $21.84, compared to$17.48 for CHCs. In contrast, CHCs had higher outreach costs ($3.34 vs.$0.17). After modeling a reduction in staffing, clinic per-screening costs ($25.69) were approximately equivalent to CHCs. CONCLUSIONS:HPV-based cervical cancer screening through community health campaigns achieved lower costs per woman screened, compared to screening at clinics. Periodic high-volume CHCs appear to be a viable low-cost strategy for implementing cervical cancer screening

Nonlinearity and Noise Effects in Multi-level Signal Millimeter-Wave over Fiber Transmission using Single- and Dual-Wavelength Modulation

We transmit multilevel quadrature amplitude modulation (QAM) data-IEEE 802.16 schemes-at 20 MSps and an orthogonal frequency-division multiplexing (OFDM) 802.11 g signal (54 Mbps) with a 25 GHz millimeter-wave over fiber system, which employs a dual wavelength source, over 20 km of single mode fiber. Downlink data transmission is successfully demonstrated over both optical and wireless (up to 12 m) paths with good error vector magnitude. An analysis of two different schemes, in which data is applied to one (single) and both (dual) of the wavelengths of a dual wavelength source, is carried out. The system performance is analyzed through simulation and a good match with experimental results is obtained. The analysis investigates the impact of Mach-Zehnder modulator (MZM) and RF amplifier nonlinearity and various noise sources, such as laser relative intensity noise, amplified spontaneous emission, thermal, and shot noise. A comparison of single carrier QAM IEEE 802.16 and OFDM in terms of their sensitivity to the distortions from MZM and RF amplifier nonlinearity is also presented

PINK1 protects against oxidative stress by phosphorylating mitochondrial chaperone TRAP1.

Mutations in the PTEN induced putative kinase 1 (PINK1) gene cause an autosomal recessive form of Parkinson disease (PD). So far, no substrates of PINK1 have been reported, and the mechanism by which PINK1 mutations lead to neurodegeneration is unknown. Here we report the identification of TNF receptor-associated protein 1 (TRAP1), a mitochondrial molecular chaperone also known as heat shock protein 75 (Hsp75), as a cellular substrate for PINK1 kinase. PINK1 binds and colocalizes with TRAP1 in the mitochondria and phosphorylates TRAP1 both in vitro and in vivo. We show that PINK1 protects against oxidative-stress-induced cell death by suppressing cytochrome c release from mitochondria, and this protective action of PINK1 depends on its kinase activity to phosphorylate TRAP1. Moreover, we find that the ability of PINK1 to promote TRAP1 phosphorylation and cell survival is impaired by PD-linked PINK1 G309D, L347P, and W437X mutations. Our findings suggest a novel pathway by which PINK1 phosphorylates downstream effector TRAP1 to prevent oxidative-stress-induced apoptosis and implicate the dysregulation of this mitochondrial pathway in PD pathogenesis

The Role of Cold Flows and Reservoirs in Galaxy Formation With Strong Feedback

We examine gas accretion and subsequent star formation in representative galaxies from the McMaster Unbiased Galaxy Simulations (Stinson et al. 2010). Accreted gas is bimodal with a natural temperature division at $10^5$ K, near the peak of the cooling curve. Cold-mode accretion dominates inflows at early times, creating a peak in total accretion at redshift z=2-4 and declining exponentially below z$\sim$2. Hot-mode accretion peaks near z=1-2 and declines gradually. Hot-mode exceeds cold-mode accretion at z$\sim$1.8 for all four galaxies rather than when the galaxy reaches a characteristic mass. Cold-mode accretion can fuel immediate star formation, while hot-mode accretion preferentially builds a large, hot gas reservoir in the halo. Late-time star formation relies on reservoir gas accreted 2-8 Gyr prior. Thus, the reservoir allows the star formation rate to surpass the current overall gas accretion rate. Stellar feedback cycles gas from the interstellar medium back into the hot reservoir. Stronger feedback results in more gas cycling, gas removal in a galactic outflow and less star formation overall, enabling simulations to match the observed star formation history. For lower mass galaxies in particular, strong feedback can delay the star formation peak to z=1-2 from the accretion peak at z=2-4.Comment: 10 pages, 7 figures. Accepted for publication in MNRA