494 research outputs found
Deep Dive into Data Workflow
This workflow was designed to assist subject liaison librarians in self-directed exploration of the data landscape around a particular discipline. For more information, see Martin and Oehrli 2015 (http://hdl.handle.net/2027.42/117590).http://deepblue.lib.umich.edu/bitstream/2027.42/117636/1/DeepDiveintoDataWorkflow.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/117636/2/RepositoryDescriptionTool.pdfDescription of DeepDiveintoDataWorkflow.pdf : Deep Dive into Data workflow documentDescription of RepositoryDescriptionTool.pdf : Repository Description Too
The Influence of Justice Thurgood Marshall on the Development of Title VII Jurisprudence
This Article highlights Justice Marshall’s influence on the development of Title VII jurisprudence. Part I presents a brief overview of Justice Marshall’s personal and professional life before becoming a Justice to show how his experience influenced the development of his judicial philosophy. Part II summarizes the Court’s approach to some of the issues left unresolved by Congress in the initial passage of Title VII. Specifically, it explores how the Court determined what would constitute a violation of Title VII and standards of pleading and proof. Part III examines the changes in the Court’s jurisprudence before Justice Marshall retired from the bench. As the majority of Justices became less sympathetic to the protection of African Americans in the workplace, Justice Marshall’s voice of dissent emerged. Part IV concludes with a discussion of the Civil Rights Act of 1991, which vindicated Justice Marshall’s choice to dissent by adopting many of the positions taken in his departure from the majority view
A Case Study and Framing Analysis of the 2008 Salmonella Outbreak
During the summer of 2008, a nationwide Salmonella outbreak sickened more than 1,400 people; the initial cause was thought to be tomatoes, but after further investigation, jalapeno and Serrano peppers from Mexico were the cause. The purpose of this study was to examine television news coverage of the 2008 Salmonella outbreak in jalapenos with case study methodology, through the scope of framing theory, to gain an understanding of how reporters’ ideologies, attitudes, corporate pressures, and interview sources influenced the frames that were reported on national television news networks. The reporters revealed they would like to see changes within the Food and Drug Administration’s (FDA) food investigations and communications system, they had confidence in the U.S. food supply, and corporate policy did not influence news coverage. Reporters used the agency that issued the recall for an interview source; however, they also used consumer watchdog groups, industry organizations, and university researchers. This study concluded that in some instances, television news frames are influenced by the reporters’ attitudes and ideologies, and in other instances, they are not. Agricultural communicators should be proactive with the news media — ensure they know about the organization, periodically offer information, and be willing to be interviewed — so that if a crisis does occur, it is much easier to get a message out
A unified mechanism for the water hammer pulse and pulsus bisferiens in severe aortic regurgitation: Insights from wave intensity analysis
The carotid bisferiens pulse and the radial water hammer pulse are typical of severe chronic aortic regurgitation. Little is known about the mechanism of these classic cardiovascular signs identified on physical examination. We report the first characterization of these abnormal pulse patterns using wave intensity analysis (WIA) in a patient with severe aortic regurgitation. We demonstrate that an abnormally pronounced forward-traveling mid-systolic suction wave, which immediately followed the initial forward-traveling compression wave from ventricular contraction, explained these pulse patterns. This suction wave likely resulted from blood inertia, arising from a ventricle ejecting a very large stroke volume into a vasodilated arterial tree. Our report demonstrates a novel pulsatile hemodynamic mechanism that unifies the pathogenesis of the bisferiens pulse and the water-hammer pulse in severe aortic regurgitation. (C) 2017 Association for Research into Arterial Structure and Physiology. Published by Elsevier B.V. All rights reserved
Impact of diabetes mellitus on ventricular structure, arterial stiffness, and pulsatile hemodynamics in heart failure with preserved ejection fraction
Background-Heterogeneity in the underlying processes that contribute to heart failure with preserved ejection fraction (HFpEF) is increasingly recognized. Diabetes mellitus is a frequent comorbidity in HFpEF, but its impact on left ventricular and arterial structure and function in HFpEF is unknown. Methods and Results-Weassessed the impact of diabetesmellitus on left ventricular cellular and interstitial hypertrophy (assessedwith cardiacmagnetic resonance imaging, including T1mapping pregadolinium and postgadolinium administration), arterial stiffness (assessed with arterial tonometry), and pulsatile arterial hemodynamics (assessed with in-office pressure-flow analyses and 24-hour ambulatory monitoring) among 53 subjects with HFpEF (32 diabetic and 21 nondiabetic subjects). Despite few differences in clinical characteristics, diabetic subjects with HFpEF exhibited a markedly greater left ventricular mass index (78.1 [95% CI, 70.4-85.9] g versus 63.6 [95% CI, 55.8-71.3] g; P=0.0093) and indexed extracellular volume (23.6 [95% CI, 21.2-26.1] mL/m(2) versus 16.2 [95% CI, 13.1-19.4] mL/m(2); P=0.0008). Pronounced aortic stiffening was also observed in the diabetic group (carotid-femoral pulse wave velocity, 11.86 [95% CI, 10.4-13.1] m/s versus 8.8 [95% CI, 7.5-10.1] m/s; P=0.0027), with an adverse pulsatile hemodynamic profile characterized by increased oscillatory power (315 [95% CI, 258-373] mWversus 190 [95% CI, 144-236] mW; P=0.0007), aortic characteristic impedance (0.154 [95% CI, 0.124-0.183] mmHg/mL per second versus 0.096 [95% CI, 0.072-0.121] mm Hg/mL per second; P=0.0024), and forward (59.5 [95% CI, 52.8-66.1] mm Hg versus 40.1 [95% CI, 31.6-48.6] mm Hg; P=0.0010) and backward (19.6 [95% CI, 16.2-22.9] mm Hg versus 14.1 [95% CI, 10.9-17.3] mm Hg; P=0.0169) wave amplitude. Abnormal pulsatile hemodynamics were also evident in 24-hour ambulatory monitoring, despite the absence of significant differences in 24-hour systolic blood pressure between the groups. Conclusions-Diabetes mellitus is a key determinant of left ventricular remodeling, arterial stiffness, adverse pulsatile hemodynamics, and ventricular-arterial interactions in HFpEF
Aging is associated with an earlier arrival of reflected waves without a distal shift in reflection sites
Background-Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (T-INF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. T-INF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, T-INF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population -15.0 ms/decade, P<0.001; clinical population -9.07 ms/decade, P=0.003) and RWTTTL (general -15.8 ms/decade, P<0.001; clinical -11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with aging
Heuristics and policies for online pickup and delivery problems
Master ThesisIn the last few decades, increased attention has been dedicated to a speci c subclass of
Vehicle Routing Problems due to its signi cant importance in several transportation areas such as taxi companies, courier companies, transportation of people, organ transportation, etc. These problems are characterized by their dynamicity as the demands are, in general, unknown in advance and the corresponding locations are paired. This thesis addresses a version of such Dynamic Pickup and Delivery Problems, motivated by a problem arisen in an Australian courier company, which operates in Sydney, Melbourne and Brisbane, where almost every day more than a thousand transportation orders arrive and need to
be accommodated. The rm has a eet of almost two hundred vehicles of various types,
mostly operating within the city areas. Thus, whenever new orders arrive at the system the dispatchers face a complex decision regarding the allocation of the new customers within the distribution routes (already existing or new) taking into account a complex multi-level objective function.
The thesis thus focuses on the process of learning simple dispatch heuristics, and lays the foundations of a recommendation system able to rank such heuristics. We implemented eight of these, observing di erent characteristics of the current eet and orders. It incorporates an arti cial neural network that is trained on two hundred days of past data, and is supervised by schedules produced by an oracle, Indigo, which is a system able to produce suboptimal solutions to problem instances. The system opens the possibility for many dispatch policies
to be implemented that are based on this rule ranking, and helps dispatchers to manage
the vehicles of the eet. It also provides results for the human resources required each
single day and within the di erent periods of the day. We complement the quite promising
results obtained with a discussion on future additions and improvements such as channel
eet management, tra c consideration, and learning hyper-heuristics to control simple rule sequences.The thesis work was partially supported by the National ICT Australia according to the
Visitor Research Agreement contract between NICTA and Martin Damyanov Aleksandro
Isosorbide dinitrate, with or without hydralazine, does not reduce wave reflections, left ventricular hypertrophy, or myocardial fibrosis in patients with heart failure with preserved ejection fraction
Background-Wave reflections, which are increased in patients with heart failure with preserved ejection fraction, impair diastolic function and promote pathologic myocardial remodeling. Organic nitrates reduce wave reflections acutely, but whether this is sustained chronically or affected by hydralazine coadministration is unknown. Methods and Results-We randomized 44 patients with heart failure with preserved ejection fraction in a double-blinded fashion to isosorbide dinitrate (ISDN; n=13), ISDN+hydralazine (ISDN+hydral; n=15), or placebo (n=16) for 6months. The primary end point was the change in reflection magnitude (RM; assessed with arterial tonometry and Doppler echocardiography). Secondary end points included change in left ventricular mass and fibrosis, measured with cardiac magnetic resonance imaging, and the 6-minute walk distance. ISDN reduced aortic characteristic impedance (mean baseline=0.15 [95% CI, 0.14-0.17], 3 months=0.11 [95% CI, 0.10-0.13], 6 months=0.10 [95% CI, 0.08-0.12] mmHg/mL per second; P=0.003) and forward wave amplitude (P-f, mean baseline=54.8 [95% CI, 47.6-62.0], 3 months=42.2 [95% CI, 33.2-51.3]; 6 months=37.0 [95% CI, 27.2-46.8] mmHg, P=0.04), but had no effect on RM (P=0.64), left ventricular mass (P=0.33), or fibrosis (P=0.63). ISDN+hydral increased RM (mean baseline=0.39 [95% CI, 0.35-0.43]; 3 months=0.31 [95% CI, 0.25-0.36]; 6 months=0.44 [95% CI, 0.37-0.51], P=0.03), reduced 6-minute walk distance (mean baseline=343.3 [95% CI, 319.2-367.4]; 6 months=277.0 [95% CI, 242.7-311.4] meters, P=0.022), and increased native myocardial T1 (mean baseline=1016.2 [95% CI, 1002.7-1029.7]; 6 months=1054.5 [95% CI, 1036.5-1072.3], P=0.021). A high proportion of patients experienced adverse events with active therapy (ISDN=61.5%, ISDN+hydral=60.0%; placebo=12.5%; P=0.007). Conclusions-ISDN, with or without hydralazine, does not exert beneficial effects on RM, left ventricular remodeling, or submaximal exercise and is poorly tolerated. ISDN+hydral appears to have deleterious effects on RM, myocardial remodeling, and submaximal exercise. Our findings do not support the routine use of these vasodilators in patients with heart failure with preserved ejection fraction
Non-invasive intraventricular pressure differences estimated with cardiac MRI in subjects without heart failure and with heart failure with reduced and preserved ejection fraction
Objective Non-invasive assessment of left ventricular (LV) diastolic and systolic function is important to better understand physiological abnormalities in heart failure (HF). The spatiotemporal pattern of LV blood flow velocities during systole and diastole can be used to estimate intraventricular pressure differences (IVPDs). We aimed to demonstrate the feasibility of an MRI-based method to calculate systolic and diastolic IVPDs in subjects without heart failure (No-HF), and with HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF).
Methods We studied 159 subjects without HF, 47 subjects with HFrEF and 32 subjects with HFpEF. Diastolic and systolic intraventricular flow was measured using two-dimensional in-plane phase-contrast MRI. The Euler equation was solved to compute IVPDs in diastole (mitral base to apex) and systole (apex to LV outflow tract).
Results Subjects with HFpEF demonstrated a higher magnitude of the early diastolic reversal of IVPDs (-1.30 mm Hg) compared with the No-HF group (-0.78 mm Hg) and the HFrEF group (-0.75 mm Hg; analysis of variance p=0.01). These differences persisted after adjustment for clinical variables, Doppler-echocardiographic parameters of diastolic filling and measures of LV structure (No-HF=-0.72; HFrEF=-0.87; HFpEF=-1.52 mm Hg; p=0.006). No significant differences in systolic IVPDs were found in adjusted models. IVPD parameters demonstrated only weak correlations with standard Doppler-echocardiographic parameters.
Conclusions Our findings suggest distinct patterns of systolic and diastolic IVPDs in HFpEF and HFrEF, implying differences in the nature of diastolic dysfunction between the HF subtypes
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