Phonon Pulse Shape Discrimination in SuperCDMS Soudan

SuperCDMS is the next phase of the Cryogenic Dark Matter Search experiment, which measures both phonon and charge signals generated by particle recoils within a germanium target mass. Charge signals are employed both in the definition of a fiducial volume and in the rejection of electron recoil background events. Alternatively, phonons generated by the charge carriers can also be used for the same two goals. This paper describes preliminary efforts to observe and quantify these contributions to the phonon signal and then use them to reject background events. A simple analysis using only one pulse shape parameter shows bulk electron recoil vs. bulk nuclear recoil discrimination to the level of 1:10^3 (limited by the statistics of the data), with little degradation in discrimination ability down to at least 7 keV recoil energy. Such phonon-only discrimination can provide a useful cross-check to the standard discrimination methods, and it also points towards the potential of a device optimized for a phonon-only measurement.Comment: Low Temperature Detector 14 conference proceedings, to be published in a special issue of the Journal of Low Temperature Physic

PAM50 molecular intrinsic subtypes in the nurses' health Study cohorts

Background: Modified median and subgroup-specific gene subtypes by PAM50 and IHC surrogates improved to fair centering are two essential preprocessing methods to assign when Luminal subtypes were grouped together. Using the breast cancer molecular subtypes by PAM50. We evaluated the modified median method, our study consisted of 46% PAM50 subtypes derived from both methods in a subset of Luminal A, 18% Luminal B, 14% HER2-enriched, 15% Nurses' Health Study (NHS) and NHSII participants; correlat-Basal-like, and 8% Normal-like subtypes; 53% of tumor-ed tumor subtypes by PAM50 with IHC surrogates; and adjacent tissues were Normal-like. Women with the Basal-characterized the PAM50 subtype distribution, proliferation like subtype had a higher rate of relapse within 5 years. scores, and risk of relapse with proliferation and tumor size HER2-enriched subtypes had poorer outcomes prior to weighted (ROR-PT) scores in the NHS/NHSII. 1999. Methods: PAM50 subtypes, proliferation scores, and Conclusions: Either preprocessing method may be uti-ROR-PT scores were calculated for 882 invasive breast tumors lized to derive PAM50 subtypes for future studies. The and 695 histologically normal tumor-adjacent tissues. Cox majority of NHS/NHSII tumor and tumor-adjacent tissues proportional hazards models evaluated the relationship were classified as Luminal A and Normal-like, respectively. between PAM50 subtypes or ROR-PT scores/groups with Impact: Preprocessing methods are important for the recurrence-free survival (RFS) or distant RFS. accurate assignment of PAM50 subtypes. These data provide Results: PAM50 subtypes were highly comparable evidence that either preprocessing method can be used in between the two methods. The agreement between tumor epidemiologic studies

CDMS, Supersymmetry and Extra Dimensions

The CDMS experiment aims to directly detect massive, cold dark matter particles originating from the Milky Way halo. Charge and lattice excitations are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK, allowing to separate nuclear recoils from the dominating electromagnetic background. The operation of 12 detectors in the Soudan mine for 75 live days in 2004 delivered no evidence for a signal, yielding stringent limits on dark matter candidates from supersymmetry and universal extra dimensions. Thirty Ge and Si detectors are presently installed in the Soudan cryostat, and operating at base temperature. The run scheduled to start in 2006 is expected to yield a one order of magnitude increase in dark matter sensitivity.Comment: To be published in the proceedings of the 7th UCLA symposium on sources and detection of dark matter and dark energy in the universe, Marina del Rey, Feb 22-24, 200

Prognostic and predictive value of androgen receptor expression in postmenopausal women with estrogen receptor-positive breast cancer : results from the Breast International Group Trial 1-98

The androgen receptor (AR) is an emerging prognostic marker and therapeutic target in breast cancer. AR is expressed in 60-80% of breast cancers, with higher prevalence among estrogen receptor-positive (ER+) tumors. Androgen treatment inhibits ER signaling in ER+/AR+ breast cancer cell lines, and AR expression is associated with improved survival for this subtype in epidemiologic studies. However, whether AR expression modifies the efficacy of selective ER modulators or aromatase inhibitors for ER+ cancers remains unclear

Demonstration of surface electron rejection with interleaved germanium detectors for dark matter searches

The SuperCDMS experiment in the Soudan Underground Laboratory searches for dark matter with a 9-kg array of cryogenic germanium detectors. Symmetric sensors on opposite sides measure both charge and phonons from each particle interaction, providing excellent discrimination between electron and nuclear recoils, and between surface and interior events. Surface event rejection capabilities were tested with two 210 Pb sources producing ∼130 beta decays/hr. In ∼800 live hours, no events leaked into the 8–115 keV signal region, giving upper limit leakage fraction 1.7 × 10−5 at 90% C.L., corresponding to < 0.6 surface event background in the future 200-kg SuperCDMS SNOLAB experiment

Energy loss due to defect formation from 206Pb recoils in SuperCDMS germanium detectors

The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of (6:08 ± 0:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7+0.6−0.5 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches