Chiral perturbation theory for electroweak reactions on deuterium

I summarize two recent applications of chiral perturbation theory to electromagnetic reactions on deuterium: elastic electron-deuteron scattering, and Compton scattering on deuterium. Both calculations have now been carried out to three orders in the chiral expansion. The expansion shows good convergence and is able to reproduce data for q < 600 MeV in e-d and for omega=55-95 MeV in gamma-d. These results demonstrate that ChiPT can be used to reliably compute operators and wave functions for low-momentum-transfer reactions in light nuclear systems.Comment: 10 pages, 6 figures. Write-up of invited talk at INT Workshop on "Nuclear Forces and the Quantum Many-Body Problem", October 4-8, 200

Inorganic carbon and pCO(2) variability during ice formation in the Beaufort Gyre of the Canada Basin.

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in DeGrandpre, M. D., Lai, C., Timmermans, M., Krishfield, R. A., Proshutinsky, A., & Torres, D. Inorganic carbon and pCO(2) variability during ice formation in the Beaufort Gyre of the Canada Basin. Journal of Geophysical Research-Oceans, 124(6), (2019): 4017-4028, doi:10.1029/2019JC015109.Solute exclusion during sea ice formation is a potentially important contributor to the Arctic Ocean inorganic carbon cycle that could increase as ice cover diminishes. When ice forms, solutes are excluded from the ice matrix, creating a brine that includes dissolved inorganic carbon (DIC) and total alkalinity (AT). The brine sinks, potentially exporting DIC and AT to deeper water. This phenomenon has rarely been observed, however. In this manuscript, we examine a ~1 year pCO2 mooring time series where a ~35‐μatm increase in pCO2 was observed in the mixed layer during the ice formation period, corresponding to a simultaneous increase in salinity from 27.2 to 28.5. Using salinity and ice based mass balances, we show that most of the observed increases can be attributed to solute exclusion during ice formation. The resulting pCO2 is sensitive to the ratio of AT and DIC retained in the ice and the mixed layer depth, which controls dilution of the ice‐derived AT and DIC. In the Canada Basin, of the ~92 μmol/kg increase in DIC, 17 μmol/kg was taken up by biological production and the remainder was trapped between the halocline and the summer stratified surface layer. Although not observed before the mooring was recovered, this inorganic carbon was likely later entrained with surface water, increasing the pCO2 at the surface. It is probable that inorganic carbon exclusion during ice formation will have an increasingly important influence on DIC and pCO2 in the surface of the Arctic Ocean as seasonal ice production and wind‐driven mixing increase with diminishing ice cover.Research Associate Cory Beatty (University of Montana) prepared the CO2 instruments and helped with the mooring deployments and data processing. Pierce Fix (undergraduate intern, University of Montana) helped with the mass balance modeling. The moorings were designed and deployed by personnel at Woods Hole Oceanographic Institution. Michiyo Yamamoto‐Kawai (University of Tokyo) and Marty Davelaar (Institute of Ocean Sciences; IOS) provided the alkalinity and dissolved inorganic carbon data. We thank the captain, officers, crew, and chief scientists (Bill Williams and Sarah Zimmerman, IOS) of the CCGS Louis S. St. Laurent. The data used in this study are available through the U.S. National Science Foundation (NSF) Arctic Data Center (https://arcticdata.io). This research was made possible by grants from the NSF Arctic Observing Network program (ARC‐1107346, PLR‐1302884, PLR‐1504410, and PLR‐1723308)

Regulation of Small RNA Accumulation in the Maize Shoot Apex

MicroRNAs (miRNAs) and trans-acting siRNAs (ta-siRNAs) are essential to the establishment of adaxial–abaxial (dorsoventral) leaf polarity. Tas3-derived ta-siRNAs define the adaxial side of the leaf by restricting the expression domain of miRNA miR166, which in turn demarcates the abaxial side of leaves by restricting the expression of adaxial determinants. To investigate the regulatory mechanisms that allow for the precise spatiotemporal accumulation of these polarizing small RNAs, we used laser-microdissection coupled to RT-PCR to determine the expression profiles of their precursor transcripts within the maize shoot apex. Our data reveal that the pattern of mature miR166 accumulation results, in part, from intricate transcriptional regulation of its precursor loci and that only a subset of mir166 family members contribute to the establishment of leaf polarity. We show that miR390, an upstream determinant in leaf polarity whose activity triggers tas3 ta-siRNA biogenesis, accumulates adaxially in leaves. The polar expression of miR390 is established and maintained independent of the ta-siRNA pathway. The comparison of small RNA localization data with the expression profiles of precursor transcripts suggests that miR166 and miR390 accumulation is also regulated at the level of biogenesis and/or stability. Furthermore, mir390 precursors accumulate exclusively within the epidermal layer of the incipient leaf, whereas mature miR390 accumulates in sub-epidermal layers as well. Regulation of miR390 biogenesis, stability, or even discrete trafficking of miR390 from the epidermis to underlying cell layers provide possible mechanisms that define the extent of miR390 accumulation within the incipient leaf, which patterns this small field of cells into adaxial and abaxial domains via the production of tas3-derived ta-siRNAs

Automatic breach detection during spine pedicle drilling based on vibroacoustic sensing

Pedicle drilling is a complex and critical spinal surgery task. Detecting breach or penetration of the surgical tool to the cortical wall during pilot-hole drilling is essential to avoid damage to vital anatomical structures adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves. Currently, the guidance of pedicle drilling is done using image-guided methods that are radiation intensive and limited to the preoperative information. This work proposes a new radiation-free breach detection algorithm leveraging a non-visual sensor setup in combination with deep learning approach. Multiple vibroacoustic sensors, such as a contact microphone, a free-field microphone, a tri-axial accelerometer, a uni-axial accelerometer, and an optical tracking system were integrated into the setup. Data were collected on four cadaveric human spines, ranging from L5 to T10. An experienced spine surgeon drilled the pedicles relying on optical navigation. A new automatic labeling method based on the tracking data was introduced. Labeled data was subsequently fed to the network in mel-spectrograms, classifying the data into breach and non-breach. Different sensor types, sensor positioning, and their combinations were evaluated. The best results in breach recall for individual sensors could be achieved using contact microphones attached to the dorsal skin (85.8\%) and uni-axial accelerometers clamped to the spinous process of the drilled vertebra (81.0\%). The best-performing data fusion model combined the latter two sensors with a breach recall of 98\%. The proposed method shows the great potential of non-visual sensor fusion for avoiding screw misplacement and accidental bone breaches during pedicle drilling and could be extended to further surgical applications

Automatic breach detection during spine pedicle drilling based on vibroacoustic sensing

Pedicle drilling is a complex and critical spinal surgery task. Detecting breach or penetration of the surgical tool to the cortical wall during pilot-hole drilling is essential to avoid damage to vital anatomical structures adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves. Currently, the guidance of pedicle drilling is done using image-guided methods that are radiation intensive and limited to the preoperative information. This work proposes a new radiation-free breach detection algorithm leveraging a non-visual sensor setup in combination with deep learning approach. Multiple vibroacoustic sensors, such as a contact microphone, a free-field microphone, a tri-axial accelerometer, a uni-axial accelerometer, and an optical tracking system were integrated into the setup. Data were collected on four cadaveric human spines, ranging from L5 to T10. An experienced spine surgeon drilled the pedicles relying on optical navigation. A new automatic labeling method based on the tracking data was introduced. Labeled data was subsequently fed to the network in mel-spectrograms, classifying the data into breach and non-breach. Different sensor types, sensor positioning, and their combinations were evaluated. The best results in breach recall for individual sensors could be achieved using contact microphones attached to the dorsal skin (85.8%) and uni-axial accelerometers clamped to the spinous process of the drilled vertebra (81.0%). The best-performing data fusion model combined the latter two sensors with a breach recall of 98%. The proposed method shows the great potential of non-visual sensor fusion for avoiding screw misplacement and accidental bone breaches during pedicle drilling and could be extended to further surgical applications

Prevention of incisional hernia with prophylactic onlay and sublay mesh reinforcement vs. primary suture only in midline laparotomies (PRIMA):long-term outcomes of a multicentre, double-blind, randomised controlled trial

Background: Incisional hernia occurs approximately in 40% of high-risk patients after midline laparotomy. Prophylactic mesh placement has shown promising results, but long-term outcomes are needed. The present study aimed to assess the long-term incisional hernia rates of the previously conducted PRIMA trial with radiological follow-up. Methods: In the PRIMA trial, patients with increased risk of incisional hernia formation (AAA or BMI ≥27 kg/m2) were randomised in a 1:2:2 ratio to primary suture, onlay mesh or sublay mesh closure in three different countries in eleven institutions. Incisional hernia during follow-up was diagnosed by any of: CT, ultrasound and physical examination, or during surgery. Assessors and patients were blinded until 2-year follow-up. Time-to-event analysis according to intention-to-treat principle was performed with the Kaplan–Meier method and Cox proportional hazard models. Trial registration: NCT00761475 (ClinicalTrials.gov). Findings: Between 2009 and 2012, 480 patients were randomized: 107 primary suture, 188 onlay mesh and 185 sublay mesh. Five-year incisional hernia rates were 53.4% (95% CI: 40.4–64.8), 24.7% (95% CI: 12.7–38.8), 29.8% (95% CI: 17.9–42.6), respectively. Compared to primary suture, onlay mesh (HR: 0.390, 95% CI: 0.248–0.614, p &lt; 0.001) and sublay mesh (HR: 0.485, 95% CI: 0.309–0.761, p = 0.002) were associated with a significantly lower risk of incisional hernia development. Interpretation: Prophylactic mesh placement remained effective in reducing incisional hernia occurrence after midline laparotomy in high-risk patients during long-term follow-up. Hernia rates in the primary suture group were higher than previously anticipated. Funding: B. Braun.</p

Prevention of incisional hernia with prophylactic onlay and sublay mesh reinforcement vs. primary suture only in midline laparotomies (PRIMA):long-term outcomes of a multicentre, double-blind, randomised controlled trial

Background: Incisional hernia occurs approximately in 40% of high-risk patients after midline laparotomy. Prophylactic mesh placement has shown promising results, but long-term outcomes are needed. The present study aimed to assess the long-term incisional hernia rates of the previously conducted PRIMA trial with radiological follow-up. Methods: In the PRIMA trial, patients with increased risk of incisional hernia formation (AAA or BMI ≥27 kg/m2) were randomised in a 1:2:2 ratio to primary suture, onlay mesh or sublay mesh closure in three different countries in eleven institutions. Incisional hernia during follow-up was diagnosed by any of: CT, ultrasound and physical examination, or during surgery. Assessors and patients were blinded until 2-year follow-up. Time-to-event analysis according to intention-to-treat principle was performed with the Kaplan–Meier method and Cox proportional hazard models. Trial registration: NCT00761475 (ClinicalTrials.gov). Findings: Between 2009 and 2012, 480 patients were randomized: 107 primary suture, 188 onlay mesh and 185 sublay mesh. Five-year incisional hernia rates were 53.4% (95% CI: 40.4–64.8), 24.7% (95% CI: 12.7–38.8), 29.8% (95% CI: 17.9–42.6), respectively. Compared to primary suture, onlay mesh (HR: 0.390, 95% CI: 0.248–0.614, p &lt; 0.001) and sublay mesh (HR: 0.485, 95% CI: 0.309–0.761, p = 0.002) were associated with a significantly lower risk of incisional hernia development. Interpretation: Prophylactic mesh placement remained effective in reducing incisional hernia occurrence after midline laparotomy in high-risk patients during long-term follow-up. Hernia rates in the primary suture group were higher than previously anticipated. Funding: B. Braun.</p

A Time Projection Chamber with GEM-Based Readout

For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.Comment: 22 pages, 19 figure

Toward quantifying the increasing role oceanic heat in sea ice loss in the new Arctic

Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 96 (2015): 2079–2105, doi:10.1175/BAMS-D-13-00177.1.The loss of Arctic sea ice has emerged as a leading signal of global warming. This, together with acknowledged impacts on other components of the Earth system, has led to the term “the new Arctic.” Global coupled climate models predict that ice loss will continue through the twenty-first century, with implications for governance, economics, security, and global weather. A wide range in model projections reflects the complex, highly coupled interactions between the polar atmosphere, ocean, and cryosphere, including teleconnections to lower latitudes. This paper summarizes our present understanding of how heat reaches the ice base from the original sources—inflows of Atlantic and Pacific Water, river discharge, and summer sensible heat and shortwave radiative fluxes at the ocean/ice surface—and speculates on how such processes may change in the new Arctic. The complexity of the coupled Arctic system, and the logistic and technological challenges of working in the Arctic Ocean, require a coordinated interdisciplinary and international program that will not only improve understanding of this critical component of global climate but will also provide opportunities to develop human resources with the skills required to tackle related problems in complex climate systems. We propose a research strategy with components that include 1) improved mapping of the upper- and middepth Arctic Ocean, 2) enhanced quantification of important process, 3) expanded long-term monitoring at key heat-flux locations, and 4) development of numerical capabilities that focus on parameterization of heat-flux mechanisms and their interactions.2016-06-0