Bootstrapping One-Loop QCD Amplitudes with General Helicities

The recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD combines the unitarity method with loop-level on-shell recursion. For generic helicity configurations, the recursion relations may involve undetermined contributions from non-standard complex singularities or from large values of the shift parameter. Here we develop a strategy for sidestepping difficulties through use of pairs of recursion relations. To illustrate the strategy, we present sets of recursion relations needed for obtaining n-gluon amplitudes in QCD. We give a recursive solution for the one-loop n-gluon QCD amplitudes with three or four color-adjacent gluons of negative helicity and the remaining ones of positive helicity. We provide an explicit analytic formula for the QCD amplitude A_{6;1}(1^-,2^-,3^-,4^+,5^+,6^+), as well as numerical results for A_{7;1}(1^-,2^-,3^-,4^+,5^+,6^+,7^+), A_{8;1}(1^-,2^-,3^-,4^+,5^+,6^+,7^+,8^+), and A_{8;1}(1^-,2^-,3^-,4^-,5^+,6^+,7^+,8^+). We expect the on-shell bootstrap approach to have widespread applications to phenomenological studies at colliders.Comment: 77 pages, 17 figures; v2, corrected minor typos in text and small equation

Implementing a Comprehensive Risk Assessment for Early Onset Sepsis to Reduce Antibiotic Usage in the NICU

Recent research and a change in guidance from the American Academy of Pediatrics (AAP) regarding the management of early onset sepsis shows that the historical practice of empiric antibiotic administration to well-appearing newborn infants exposed to chorioamnionitis is uneccesary and may be harmful to their future health. This project aimed to standardize the risk assessment and management of these infants born at greater than or equal to 35 weeks gestation at Thomas Jefferson University Hospital (TJUH) in order to decrease their exposure to antibiotics. Using healthcare quality improvement methodology, a new assessment and management guideline based upon local clinical research and guidance from the AAP was developed and implemented at TJUH. Following initiation of the project, empiric antibiotic adminsitration in this cohort of neonates decreased from 100% to 34% with no evidence of missed or undertreated cases of early onset sepsis. Antibiotic usage in the NICU can be significantly and safely reduced by implementing an evidence-based comprehensive risk assessment and management guideline similar to the one developed for this project

Organizational identification and independent sales contractor performance in professional services

Purpose The purpose of this paper is to examine the drivers of independent sales contractor (ISC) performance. As independently contracted sales agents, the ISC model is a growing method of non-permanent employment utilized in many sectors. Specifically, this study seeks to fill a gap in the literature related to the under-researched link between ISCs and organizational identification. Design/methodology/approach This study conducts an exploratory, mixed-methods study based on data collected from 189 ISCs from a professional services firm. Findings Results demonstrate that outcomes related to sales performance, retention and advocacy are influenced directly and indirectly by organizational identification. It also shows that tangible benefits related to financial and marketing values are the strongest predictors of ISC organizational identification. Intangible dimensions such as value congruence, management trust and embeddedness play a limited role in the model. Research limitations/implications Results show that ISC sales performance is enhanced when an ISC views their identity and the identity of the firm as highly interdependent. These findings suggest that organizational identification can be a key performance indicator when evaluating the return on marketing investment for a firm. Practical implications This study provides some important guidance to managers responsible for ISCs. First, the study identifies the primary drivers of organizational identification. Specifically, the study demonstrates that financial and marketing benefits are the primary relational antecedents of organizational identification. Both value congruence and operational benefits play relatively minor roles. Similarly, the results show that both organizational identification and historic sales performance are critical predictors of sales performance. Originality/value Few researchers have examined the link between ISCs and organizational identification. Organizational identification is of particular importance in the study of ISCs, as they possess the dual identity of an independent agent and that of a sales representative of the firm they are under contract. This study contributes to existing literature by extending previous studies that examine antecedents of sales performance

Accelerated cardiovascular magnetic resonance of the mouse heart using self-gated parallel imaging strategies does not compromise accuracy of structural and functional measures

BACKGROUND: Self-gated dynamic cardiovascular magnetic resonance (CMR) enables non-invasive visualization of the heart and accurate assessment of cardiac function in mouse models of human disease. However, self-gated CMR requires the acquisition of large datasets to ensure accurate and artifact-free reconstruction of cardiac cines and is therefore hampered by long acquisition times putting high demands on the physiological stability of the animal. For this reason, we evaluated the feasibility of accelerating the data collection using the parallel imaging technique SENSE with respect to both anatomical definition and cardiac function quantification. RESULTS: Findings obtained from accelerated data sets were compared to fully sampled reference data. Our results revealed only minor differences in image quality of short- and long-axis cardiac cines: small anatomical structures (papillary muscles and the aortic valve) and left-ventricular (LV) remodeling after myocardial infarction (MI) were accurately detected even for 3-fold accelerated data acquisition using a four-element phased array coil. Quantitative analysis of LV cardiac function (end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and LV mass) in healthy and infarcted animals revealed no substantial deviations from reference (fully sampled) data for all investigated acceleration factors with deviations ranging from 2% to 6% in healthy animals and from 2% to 8% in infarcted mice for the highest acceleration factor of 3.0. CNR calculations performed between LV myocardial wall and LV cavity revealed a maximum CNR decrease of 50% for the 3-fold accelerated data acquisition when compared to the fully-sampled acquisition. CONCLUSIONS: We have demonstrated the feasibility of accelerated self-gated retrospective CMR in mice using the parallel imaging technique SENSE. The proposed method led to considerably reduced acquisition times, while preserving high spatial resolution at sufficiently high CNR. The accuracy of measurements of both structural and functional parameters of the mouse heart was not compromised by the application of the proposed accelerated data acquisition method

Exaggerated Sexual Swellings and the Probability of Conception in Wild Sanje Mangabeys (Cercocebus sanjei)

© 2017, The Author(s). Females of several catarrhine primate species exhibit exaggerated sexual swellings that change in size and coloration during the menstrual cycle and, in some species, gestation. Although their function remains under debate, studies indicate that swellings may contain information males could use to discern ovulation and the probability that a cycle will be conceptive. Here we combine visual ratings of swellings with hormonal data for a group of Sanje mangabeys (18 adult, 3 adolescent females) to determine if their swellings provide reliable information on female fertility. In all cases where ovulation was detected (N=7), it occurred during maximum tumescence, and in 83.3% during the first two days of the “shiny phase,” a period during maximum tumescence when the swelling was brightest. There were no significant differences in maximum tumescence and shiny phase duration among cycles of different probability of conception, although there was a trend toward conceptive cycles exhibiting shorter shiny phases than nonconceptive ones. Only 25% (N=4) of postconceptive swellings developed the shiny phase, and adolescents displayed the longest maximum tumescence and shiny phases. The conspicuous nature of the shiny phase and the frequent overlap between its onset and ovulation suggest that its presence serves as a general signal of ovulation and that the cycle has a high probability of being conceptive. It also suggests that swellings in some Sanje mangabeys are more accurate signals of fertility than in other primates

Examining the Effect of Kindlin-3 Binding Site Mutation on LFA-1-ICAM-1 Bonds by Force Measuring Optical Tweezers

Integrins in effector T cells are crucial for cell adhesion and play a central role in cell-mediated immunity. Leukocyte adhesion deficiency (LAD) type III, a genetic condition that can cause death in early childhood, highlights the importance of integrin/kindlin interactions for immune system function. A TTT/AAA mutation in the cytoplasmic domain of the beta 2 integrin significantly reduces kindlin-3 binding to the beta 2 tail, abolishes leukocyte adhesion to intercellular adhesion molecule 1 (ICAM-1), and decreases T cell trafficking in vivo. However, how kindlin-3 affects integrin function in T cells remains incompletely understood. We present an examination of LFA-1/ICAM-1 bonds in both wild-type effector T cells and those with a kindlin-3 binding site mutation. Adhesion assays show that effector T cells carrying the kindlin-3 binding site mutation display significantly reduced adhesion to the integrin ligand ICAM-1. Using optical trapping, combined with back focal plane interferometry, we measured a bond rupture force of 17.85 +/- 0.63 pN at a force loading rate of 30.21 +/- 4.35 pN/s, for single integrins expressed on wild-type cells. Interestingly, a significant drop in rupture force of bonds was found for TTT/AAA-mutant cells, with a measured rupture force of 10.08 +/- 0.88pN at the same pulling rate. Therefore, kindlin-3 binding to the cytoplasmic tail of the beta 2-tail directly affects catch bond formation and bond strength of integrin-ligand bonds. As a consequence of this reduced binding, CD8+ T cell activation in vitro is also significantly reduced.Peer reviewe

On-Shell Unitarity Bootstrap for QCD Amplitudes

We describe the recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD. The method combines the unitarity method with loop-level on-shell recursion. The unitarity method is used to compute cut-containing parts of amplitudes, and on-shell recursion is used for the remaining rational terms.Comment: 10 pages, 9 figures, write-up of talks given by Z. Bern and D. A. Kosower at Loops & Legs 2006, Eisenach, Germany; v2: added referenc

Is NIPPV Superior to CPAP in Maintaining Targeted Oxygen Saturation Ranges in Preterm Infants on Moderate Non-Invasive Respiratory Support?

Background: Non-invasive positive pressure ventilation (NIPPV) and continuous positive airway pressure (CPAP) are non-invasive respiratory supports commonly used in preterm infants. There is conflicting data on the superiority between these two modes of non-invasive respiratory support. The objective of this study was to determine if oxygen saturation is more within the target range on NIPPV compared to CPAP using the data from histograms. Methods: Retrospective analysis of premature neonates (\u3c 1500 grams, gestational age \u3c 30 weeks) admitted to the NICU for which oxygen saturation histogram data was available one day before and after the transition between NIPPV and CPAP. FiO2 at the time of data collection was greater than 21 percent. This histogram data, the percentage of time spent in certain SpO2 ranges, was compared before and after the de-escalation from NIPPV to CPAP or escalation from CPAP to NIPPV. FiO2 was additionally compared between the two modes of respiratory support. Results: A total of 26 infants were included. The median gestational age was 25.5 weeks and the median weight of the infants was 792 grams. Among the 26 infants, there were 34 episodes of transition between NIPPV and CPAP, 19 switches from NIPPV to CPAP, and 15 from CPAP to NIPPV. The percentage of time that oxygen saturation was within the target range (89-94 %) was not statistically significant between the two modes of respiratory support (CPAP 39.9% vs. NIPPV 43.9%, p=0.09) (Table 1). The percentage of time that oxygen saturation was between 86-88% was higher on NIPPV and the percentage of time that oxygen saturation was \u3e94% was higher on CPAP. There was a trend towards lower FiO2 on NIPPV compared to CPAP. When switched from NIPPV to CPAP, there was a higher percentage of time spent above the target range ( \u3e94%) while on CPAP (56% vs 49%, p=0.001), and below the target range (86-88%) while on NIPPV (5.0% vs 1.4%, p=0.02) (Table 3). When switched from CPAP to NIPPV, there was no difference in oxygen saturation ranges (Table 2). Conclusion: Target oxygen saturation ranges on histogram data were similar in premature infants when supported on CPAP and NIPPV. However, oxygen saturation below the target range was more frequent on NIPPV compared to CPAP. NIPPV is not superior to CPAP in maintaining oxygen saturation within the target range in premature infants on moderate non-invasive respiratory support. The potential risk of low oxygen saturation range while supported on NIPPV in preterm infants requires further research.https://jdc.jefferson.edu/pulmcritcareposters/1003/thumbnail.jp