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Search Results: 1 - 10 of 300678 matches for " Lisa J. Kaufman "
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Recent Results in Neutrinoless Double Beta Decay
Lisa J. Kaufman
Physics , 2013,
Abstract: The search for neutrinoless double beta decay is a rich source for new physics. The observation of this decay will lead to understanding of the absolute mass scale of neutrinos, the Majorana nature of the neutrino (whether the neutrino is its own anti-particle), and lepton number violation. Double beta decay is being investigated around the world by several experiments using different candidate isotopes. There has been much progress made in experimental techniques recently such that achieving sensitivity to neutrino masses at 50 meV and below will be possible in the near future. A summary of recent results in neutrinoless double beta decay is discussed with a look toward the experimental goals for the future.
Facial Motion Engages Predictive Visual Mechanisms
Jordy Kaufman, Patrick J. Johnston
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091038
Abstract: We employed a novel cuing paradigm to assess whether dynamically versus statically presented facial expressions differentially engaged predictive visual mechanisms. Participants were presented with a cueing stimulus that was either the static depiction of a low intensity expressed emotion; or a dynamic sequence evolving from a neutral expression to the low intensity expressed emotion. Following this cue and a backwards mask, participants were presented with a probe face that displayed either the same emotion (congruent) or a different emotion (incongruent) with respect to that displayed by the cue although expressed at a high intensity. The probe face had either the same or different identity from the cued face. The participants' task was to indicate whether or not the probe face showed the same emotion as the cue. Dynamic cues and same identity cues both led to a greater tendency towards congruent responding, although these factors did not interact. Facial motion also led to faster responding when the probe face was emotionally congruent to the cue. We interpret these results as indicating that dynamic facial displays preferentially invoke predictive visual mechanisms, and suggest that motoric simulation may provide an important basis for the generation of predictions in the visual system.
Assessment of Acute Episodes in Chronic Stable Angina: A Clinical-Laboratory Approach to the Use of the Coronary Vasodilator Propatyl Nitrate  [PDF]
Gerson Goldwasser, Renato Kaufman, Carlos Pereira Nunes, Alexandre Hid, Stephanie Wrobel Goldberg, Alessandra Santos, Lisa Oliveira, Adenilson de Souza da Fonseca, Mauro Geller
World Journal of Cardiovascular Diseases (WJCD) , 2016, DOI: 10.4236/wjcd.2016.67027
Abstract: Background/Objectives: Propatyl nitrate is a coronary vasodilator with immediate and prolonged action, indicated in the treatment and prevention of acute angina pectoris episodes. Methods: This was an open, self-paired comparative study performed at UNIFESO Medical School evaluating the clinical and laboratory results of treatment with propatyl nitrate in patients with chronic stable angina pectoris. Subjects received 10 mg of propatyl nitrate, at the dose of three sublingual tablets per day, to be taken at 8:00 A.M., 2:00 P.M., and 8:00 P.M. Subjects returned to the study center after 15 days of treatment for Visit 2 assessments, and at the end of the 30-day treatment period (Visit 3). Results: A total of 200 subjects were included in the study. There was a statistically significant reduction in blood pressure (p < 0.0001) and heart rate (p = 0.0001), but no change in respiratory rate (p = 0.23). Laboratory results did not vary throughout the treatment period. There was no significant change from pretreatment in the SAQ Physical Limitation scale (p = 0.7415). The Angina Stability, Angina Frequency, and Treatment Satisfaction, and Quality of Life scales showed a significant improvement from pretreatment (p < 0.0001). Adverse events were observed among 41 subjects at Visit 2 and 35 subjects at Visit 3. Conclusions: Propatyl nitrate was safe and effective in treating chronic stable angina pectoris over the course of the 30-day treatment period. Treatment with propatyl nitrate increased angina stability and reduced angina frequency while increasing treatment satisfaction and quality of life in the patient population evaluated.
O$_2$ Emission Toward Orion H$_2$ Peak 1 and the Role of FUV-Illuminated C-Shocks
Gary J. Melnick,Michael J. Kaufman
Physics , 2015,
Abstract: Molecular oxygen, O_2, has been the target of ground-based and space-borne searches for decades. Of the thousands of lines of sight surveyed, only those toward Rho Oph and Orion H_2 Peak 1 have yielded detections of any statistical significance. The detection of the O_2 N_J =3_3 -1_2 and 5_4 - 3_4 lines at 487.249 GHz and 773.840 GHz, respectively, toward Rho Ophiuchus has been attributed to a short-lived peak in the time-dependent, cold-cloud O_2 abundance, while the detection of the O_2 N_J =3_3 - 1_2, 5_4 - 3_4 lines, plus the 7_6 - 5_6 line at 1120.715 GHz, toward Orion has been ascribed to time-dependent preshock physical and chemical evolution and low-velocity (12 km/s) non-dissociative C-type shocks, both of which are fully shielded from far-ultraviolet (FUV) radiation, plus a postshock region that is exposed to a FUV field. We report a re-interpretation of the Orion O_2 detection based on new C-type shock models that fully incorporate the significant effects the presence of even a weak FUV field can have on the preshock gas, shock structure and postshock chemistry. In particular, we show that a family of solutions exists, depending on the FUV intensity, that reproduces both the observed O_2 intensities and O_2 line ratios. The solution in closest agreement with the shock parameters inferred for H_2 Peak 1 from other gas tracers assumes a 23 km/s shock impacting gas with a preshock density of 8x10^4 cm^-3 and G_0 =1, substantially different from that inferred for the fully-shielded shock case. As pointed out previously, the similarity between the LSR velocity of all three O_2 lines (~11 km/s) and recently measured H_2O 5_32 - 4_41 maser emission at 620.701 GHz toward H_2 Peak 1 suggests that the O_2 emission arises behind the same shocks responsible for the maser emission, though the O_2 emission is almost certainly more extended than the localized high density maser spots
Severe heparin-induced thrombocytopenia: when the obvious is not obvious, a case report
Graham M Cormack, Larry J Kaufman
Journal of Medical Case Reports , 2007, DOI: 10.1186/1752-1947-1-13
Abstract: Thrombocytopenia is a common finding in hospitalized patients, particularly critically ill patients, with readily plausible causes including disseminated intravascular coagulation, dilution from blood transfusions, continuous venovenous hemodialysis (CVVHD), liver disease with hypersplenism, and certain medications. Physicians should be vigilant in excluding the more dangerous causes of thrombocytopenia. For example, heparin-induced thrombocytopenia (HIT) warrants serious consideration because it is a potentially devastating, yet underdiagnosed, complication of one of the most commonly prescribed medications worldwide.Approximately one trillion units of heparin are administered to 12 million patients per year in the United States [1]. HIT is caused by antibodies to a complex of heparin and platelet factor 4 that activate platelets, resulting in release of procoagulant microparticles, thrombocytopenia, excessive thrombin generation, and frequently thrombosis [2]. HIT occurs in approximately 0.5% of patients with occult exposure to heparin (e.g., catheter flushes), 0.1%–1% of patients treated with low-molecular-weight heparin [3], and 3%–5% of patients receiving unfractionated heparin [4]. Although these are small percentages, the ubiquitous use of heparin puts an extremely large number of patients at risk.We present a case of severe HIT complicated by a highly hypercoagulable state, in which heparin exposure was inconspicuous and diagnosis was delayed. This case underscores the need for vigilance in suspecting HIT in any patient with thrombocytopenia and recent heparin exposure.A 75 year-old Hawaiian-Chinese female with a history of aortic stenosis, chronic renal insufficiency, and hypertension presented to her cardiologist with pitting edema of the bilateral lower extremities. On March 21st, 2005, a cardiac catheterization showed an ejection fraction of 15%, and severe aortic stenosis, aortic regurgitation, and mitral regurgitation. During catheterization, the venou
An alternative and convenient synthesis of oct-7-enal, a naturally-occurring aldehyde isolated from the Japanese thistle Cirsium dipsacolepis
Bracca, Andrea B. J.;Kaufman, Teodoro S.;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000600011
Abstract: a new synthesis of oct-7-enal, a naturally-occurring unsaturated aldehyde isolated from the japanese thistle cirsium dipsacolepis, is reported. the natural product was prepared in five steps and with good overall yield from pentane-1,5-diol.
Aerosol direct radiative effect at the top of the atmosphere over cloud free ocean derived from four years of MODIS data
L. A. Remer ,Y. J. Kaufman
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2006,
Abstract: A four year record of MODIS spaceborne data provides a new measurement tool to assess the aerosol direct radiative effect at the top of the atmosphere. MODIS derives the aerosol optical thickness and microphysical properties from the scattered sunlight at 0.55–2.1 μm. The monthly MODIS data used here are accumulated measurements across a wide range of view and scattering angles and represent the aerosol's spectrally resolved angular properties. We use these data consistently to compute with estimated accuracy of ±0.6 Wm 2 the reflected sunlight by the aerosol over global oceans in cloud free conditions. The MODIS high spatial resolution (0.5 km) allows observation of the aerosol impact between clouds that can be missed by other sensors with larger footprints. We found that over the clear-sky global ocean the aerosol reflected 5.3±0.6 Wm 2 with an average radiative efficiency of 49±2 Wm 2 per unit optical thickness. The seasonal and regional distribution of the aerosol radiative effects are discussed. The analysis adds a new measurement perspective to a climate change problem dominated so far by models.
Switching cloud cover and dynamical regimes from open to closed Benard cells in response to the suppression of precipitation by aerosols
D. Rosenfeld, Y. J. Kaufman, ,I. Koren
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2006,
Abstract: The dynamic structure of the weakly sheared atmospheric marine boundary layer (MBL) supports three distinct states of cloud cover, which are associated with the concentrations of cloud condensation nuclei (CCN) aerosols in the MBL: (i) CCN rich MBL with closed Benard cellular convection that forms nearly full cloud cover; (ii) CCN depleted MBL with open cellular convection that forms <40% cloud cover; and, (iii) CCN starved MBL where clouds cannot form due to insufficient CCN, with near zero cloud cover. Here we propose a mechanism for the transition between these three states that involves the aerosol impacts on precipitation and the feedbacks on the dynamics of the clouds and on the aerosols deposition. By suppressing precipitation aerosols can reverse the direction of the airflow, converting the cloud structure from open to closed cells and more than doubling the cloud cover. The three states possess positive feedbacks for self maintenance, so that small changes of the conditions can lead to bifurcation of the MBL cloud regime. The transition between the closed and open cells occur at near pristine background level of aerosols, creating a large sensitivity of cloud radiative forcing to very small changes in aerosols at the MBL. The third state of super clean air can occur as the more efficient precipitation in cleaner air deposits the aerosols ever faster in a runaway positive feedback process. The proposed mechanism suggests that very small changes in the aerosols input to the MBL can have large impacts on the oceanic cloud cover and likely in turn on the global temperature, in ways that are not yet accounted for in the climate models.
Switching cloud cover and dynamical regimes from open to closed Benard cells in response to the suppression of precipitation by aerosols
D. Rosenfeld,Y. J. Kaufman,I. Koren
Atmospheric Chemistry and Physics Discussions , 2006,
Abstract: The dynamic structure of the atmospheric marine boundary layer (MBL) supports two distinct states of cloud cover: closed and open Benard cellular convection. Closed cells are nearly fully cloud covered, while the open cells have <40% cloud cover. Here we show that aerosols have a greater than expected impact on the cloud cover by changing the mode of cellular convection. By suppressing precipitation aerosols can reverse the direction of the airflow, converting the cloud structure from open to closed cells and doubling the cloud cover. The two states possess positive feedbacks for self maintenance, so that small changes of the conditions can lead to bifurcation of the MBL cloud regime. The transition occurs at near pristine background level of aerosols, creating a large sensitivity of cloud radiative forcing to very small changes in aerosols at the MBL. This can have a major impact on global temperatures.
Molecular Tracers of Turbulent Shocks in Giant Molecular Clouds
A. Pon,D. Johnstone,M. J. Kaufman
Physics , 2012, DOI: 10.1088/0004-637X/748/1/25
Abstract: Giant molecular clouds contain supersonic turbulence and simulations of magnetohydrodynamic turbulence show that these supersonic motions decay in roughly a crossing time, which is less than the estimated lifetimes of molecular clouds. Such a situation requires a significant release of energy. We run models of C-type shocks propagating into gas with densities around 10^3 cm^(-3) at velocities of a few km / s, appropriate for the ambient conditions inside of a molecular cloud, to determine which species and transitions dominate the cooling and radiative energy release associated with shock cooling of turbulent molecular clouds. We find that these shocks dissipate their energy primarily through CO rotational transitions and by compressing pre-existing magnetic fields. We present model spectra for these shocks and by combining these models with estimates for the rate of turbulent energy dissipation, we show that shock emission should dominate over emission from unshocked gas for mid to high rotational transitions (J >5) of CO. We also find that the turbulent energy dissipation rate is roughly equivalent to the cosmic-ray heating rate and that the ambipolar diffusion heating rate may be significant, especially in shocked gas.
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