5,016 research outputs found
Pasolini as Jew:Between Israel and Europe
Pasolini’s first turn beyond Europe can be dated to three lengthy journeys to Asia and Africa undertaken between December 1960 and February 1963. The places he visited quickly bring to mind a long series of subsequent projects – poems, screenplays, films realized or unfinished – from throughout the remaining fifteen years of Pasolini’s life, during which he pitched himself in a wholly new light as a poet of the Third World
Relating localized nanoparticle resonances to an associated antenna problem
We conceptually unify the description of resonances existing at metallic
nanoparticles and optical nanowire antennas. To this end the nanoantenna is
treated as a Fabry-Perot resonator with arbitrary semi-nanoparticles forming
the terminations. We show that the frequencies of the quasi-static dipolar
resonances of these nanoparticles coincide with the frequency where the phase
of the complex reflection coefficient of the fundamental propagating plasmon
polariton mode at the wire termination amounts to . The lowest order
Fabry-Perot resonance of the optical wire antenna occurs therefore even for a
negligible wire length. This approach can be used either to easily calculate
resonance frequencies for arbitrarily shaped nanoparticles or for tuning the
resonance of nanoantennas by varying their termination.Comment: Submitted to Phys. Rev.
The Role of the Gouy Phase in the Coherent Phase Control of the Photoionization and Photodissociation of Vinyl Chloride
We demonstrate theoretically and experimentally that the Gouy phase of a
focused laser beam may be used to control the photo-induced reactions of a
polyatomic molecule. Quantum mechanical interference between one- and
three-photon excitation of vinyl chloride produces a small phase lag between
the dissociation and ionization channels on the axis of the molecular beam.
Away from the axis, the Gouy phase introduces a much larger phase lag that
agrees quantitatively with theory without any adjustable parameters.Comment: 4 pages, 4 figure
Pancreatic cysts suspected to be branch duct intraductal papillary mucinous neoplasm without concerning features have low risk for development of pancreatic cancer.
BackgroundThe risk of developing pancreatic cancer is uncertain in patients with clinically suspected branch duct intraductal papillary mucinous neoplasm (BD-IPMN) based on the "high-risk stigmata" or "worrisome features" criteria proposed in the 2012 international consensus guidelines ("Fukuoka criteria").MethodsRetrospective case series involving patients referred for endoscopic ultrasound (EUS) of indeterminate pancreatic cysts with clinical and EUS features consistent with BD-IPMN. Rates of pancreatic cancer occurring at any location in the pancreas were compared between groups of patients with one or more Fukuoka criteria ("Highest-Risk Group", HRG) and those without these criteria ("Lowest-Risk Group", LRG).ResultsAfter exclusions, 661 patients comprised the final cohort (250 HRG and 411 LRG patients), 62% female with an average age of 67 years and 4 years of follow up. Pancreatic cancer, primarily adenocarcinoma, occurred in 60 patients (59 HRG, 1 LRG). Prevalent cancers diagnosed during EUS, immediate surgery, or first year of follow up were found in 48/661 (7.3%) of cohort and exclusively in HRG (33/77, 42.3%). Using Kaplan-Meier method, the cumulative incidence of cancer at 7 years was 28% in HRG and 1.2% in LRG patients (P<0.001).ConclusionsThis study supports using Fukuoka criteria to stratify the immediate and long-term risks of pancreatic cancer in presumptive BD-IPMN. The risk of pancreatic cancer was highest during the first year and occurred exclusively in those with "high-risk stigmata" or "worrisome features" criteria. After the first year all BD-IPMN continued to have a low but persistent cancer risk
Clustering Analyses of 300,000 Photometrically Classified Quasars--I. Luminosity and Redshift Evolution in Quasar Bias
Using ~300,000 photometrically classified quasars, by far the largest quasar
sample ever used for such analyses, we study the redshift and luminosity
evolution of quasar clustering on scales of ~50 kpc/h to ~20 Mpc/h from
redshifts of z~0.75 to z~2.28. We parameterize our clustering amplitudes using
realistic dark matter models, and find that a LCDM power spectrum provides a
superb fit to our data with a redshift-averaged quasar bias of b_Q =
2.41+/-0.08 () for . This represents a better
fit than the best-fit power-law model (; ). We find b_Q increases with redshift.
This evolution is significant at >99.6% using our data set alone, increasing to
>99.9999% if stellar contamination is not explicitly parameterized. We measure
the quasar classification efficiency across our full sample as a = 95.6 +/-
^{4.4}_{1.9}%, a star-quasar separation comparable with the star-galaxy
separation in many photometric studies of galaxy clustering. We derive the mean
mass of the dark matter halos hosting quasars as MDMH=(5.2+/-0.6)x10^{12}
M_solar/h. At z~1.9 we find a deviation from luminosity-independent
quasar clustering; this suggests that increasing our sample size by a factor of
1.8 could begin to constrain any luminosity dependence in quasar bias at z~2.
Our results agree with recent studies of quasar environments at z < 0.4, which
detected little luminosity dependence to quasar clustering on proper scales >50
kpc/h. At z < 1.6, our analysis suggests that b_Q is constant with luminosity
to within ~0.6, and that, for g < 21, angular quasar autocorrelation
measurements are unlikely to have sufficient statistical power at z < 1.6 to
detect any luminosity dependence in quasars' clustering.Comment: 13 pages, 9 figures, 2 tables; uses amulateapj; accepted to Ap
C3b/iC3b Deposition on Streptococcus pneumoniae Is Not Affected by HIV Infection
Streptococcus pneumoniae is a common cause of infection in both HIV positive patients and those with complement deficiencies. We hypothesised that HIV positive individuals might exhibit reduced opsonisation of pneumococcus with complement due to reduced levels of S. pneumoniae specific IgG. We discovered no difference in C3 deposition on S. pneumoniae between HIV positive or negative individuals, and furthermore C3 deposition remained unchanged as HIV progressed towards AIDS. We found no correlation between C3 deposition on S. pneumoniae and CD4 cell count in HIV infected individuals. Hence we have demonstrated no failure of complement immunity in HIV positive patients
Distensibility Differs Between Sall Arteries and Veins in the Newborn Piglet Lung
BACKGROUND: We previously used micro-CT techniques to measure pulmonary artery distensibility in 3 week old piglets. Pressure/diameter relationships were measured for each artery and the slope (a) was then plotted against its diameter intercept at 0 pressure (Do). The resultant diameter independent distensibility parameter, a, was estimated by linear regression to be 1.6% per mmHg for arteries between 0.2 and 3.0 mm Do.
OBJECTIVE: This study sought to determine whether; 1) distensibility of smaller arteries was similar to that of arteries with Do\u3e 0.2 mm; and 2) whether small vein and artery distensibility was similar.
DESIGN/METHODS: Lower lobes were isolated and perfused with papaverine/saline to remove blood and tone. Lobar bronchi were cannulated and lobes inflated to 3 mmHg. Lobar arteries (n=13) or veins (n=12) were cannulated and perfluoroctyl bromide instilled. Small arteries (0.033 to 0.34 mm Do) and veins (0.024 to 0.33 mm Do) were imaged by planar X-ray at static pressures ranging from 21 to 3 mmHg in 3 mmHg increments. The slope of the pressure/diameter curve was estimated by linear regression (0 = Do + ~P ) for 4·8 arteries or veins per lobe. The linear relationship of all ~ vs their respective Do was plotted (0/00 = 1 + oP) to estimate distensibility.
RESULTS: In small arteries, a determined by linear regression was 1.5 ± 0.1% per mmHg as previously described in larger arteries. a estimated in the same way in small veins was significantly lower at 0.9 ± 0.1% per mmHg (p \u3c 0.05). However, the X-ray images suggested that venous diameter increased more at lower than higher pressures. a estimated over the 3-9 mmHg pressure range was 1.4 ± 0.23% per mmHg. while over the 12-21 mmHg pressure range ~ was significantly lower at 0.9% ± 0.13%.
CONCLUSIONS: Distensibility of the entire arterial tree over a wide range of pressures seems well described by a single, diameter independent parameter. In contrast, distensibility of small veins appears to be higher at low versus high pressures. Future studies must further examine distensibility of large and small veins at various pressures and relate the findings to pulmonary vascular hemodynamics
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