VAMOS 1 was a prototype detector built in 2011 at an altitude of 4100 m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.

Apoptosis is triggered in the developing mammalian brain by sedative, anesthetic or antiepileptic drugs during late gestation and early life. Whether human children are vulnerable to this toxicity mechanism remains unknown, as there are no imaging techniques to capture it. Apoptosis is characterized by distinct structural features, which affect the way damaged tissue scatters ultrasound compared to healthy tissue. We evaluated whether apoptosis, triggered by the anesthetic sevoflurane in the brains of neonatal rhesus macaques, can be detected using quantitative ultrasound (QUS).

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Goal: This study compares two strategies to compensate for attenuation in the estimation of the backscatter coefficient σ of breast cancer Methods: Attenuation compensation was performed using local attenuation estimates from a constrained Spectral-Log-Difference (CSLD) method, and average estimates from a dynamic programming (DP)-based regularized method. First, bias and linearity of σ estimates from both strategies were evaluated in a Gammex 410SCG phantom with inclusions with known σ imaged at 8 MHz on a Verasonics Vantage 128 scanner. Then, the strategies were compared in terms of the contrast-to-noise ratio (CNR) between adipose tissue and invasive ductal carcinoma. σ estimates were obtained from 10 patients with biopsy-confirmed IDCs imaged invivo with a 12L4 transducer on a Siemens Acuson S2000 as part of an IRB-approved protocol at the National Institute of Cancerology in Mexico City. DP σ estimates provided smaller bias and better linearity compared to estimates of CSLD. In the in vivo study, DP σ estimates produced negative IDC-vs-adipose CNR that was significantly different from zero (p = 0.002) and agreed with the hypoechoic appearance of IDC. [Work supported by CONACYT Ciencia de Frontera 1311307, ASA international student support, and UNAM PAPIIT IA102320. We thank Siemens Mexico for scanner loan.]