Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

Observation of high-energy neutrinos from the Galactic plane

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

Evidence for neutrino emission from the nearby active galaxy NGC 1068

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy’s active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79 − 20 + 22 neutrinos at tera–electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera–electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{μ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9}  eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{μτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19}  cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with β≳0.8 and up to β∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}. The best-fit point is found to be at sin^{2}(2θ_{24})=0.10 and Δm_{41}^{2}=4.5  eV^{2}, which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.

Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than10 28 s at 90% CL for dark matter masses above 10 TeV .

Measurement of the ν μ energy spectrum with IceCube-79: IceCube Collaboration

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9 σ in four adjacent bins for neutrino energies E ν ≥ 177.8 TeV . The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

Constraints on Ultrahigh-Energy Cosmic-Ray Sources from a Search for Neutrinos above 10 PeV with IceCube

We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9}  GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5}  GeV to above 10^{11}  GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×10^{6}  GeV, the highest neutrino energy observed so far, and (7.7±2.0)×10^{5}  GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

Searches for Sterile Neutrinos with the IceCube Detector

The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3  eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.

Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube: IceCube Collaboration

We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.

Observation of high-energy astrophysical neutrinos in three years of IceCube data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8)  GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Evidence for high-energy extraterrestrial neutrinos at the IceCube detector

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4σ level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Measurement of atmospheric neutrino oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

Measurement of the proton-air cross section at √s=57 TeV with the Pierre Auger Observatory

We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)(-36)(+28)(syst)] mb is found.

Measurement of the depth of maximum of extensive air showers above 10{18} eV

We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.

Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV

The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Feasibility and morbidity of reversal of Hartmann's

OBJECTIVE

Reversal of Hartmann's is a major surgical procedure and associated with substantial morbidity and mortality.

METHOD

This study retrospectively analysed the data at a single centre over an eight-year period to assess the clinical results and morbidity of reversal of Hartmann's.

RESULTS

One hundred and ten Hartmann's procedures were performed during the period. Only 66 (61%) of patients had a reversal. Advanced age and comorbidity were the primary reasons for not reversing. Complications among the 66 patients (36 males and 30 females) who underwent reversal occurred in 26 (41%). There were no deaths. Patients who underwent reversal were ASA 2 (60%), ASA 3 (25%) and ASA 4 (4.6%). Univariate analysis demonstrated a significant association between complications following reversal and ASA grade (P =0.01), and hypertension (P = 0.03) There was no correlation between the patient variables and anastomotic leakage. Multiple logistic regression analysis showed a significant influence of hypertension, smoking and ASA grade on complications.

CONCLUSIONS

About 40% of patients who undergo Hartmann's procedure will not have a reversal. Reversal is a feasible operation for selected patients, but there is a high complication rate.

Second eye of patients with unilateral neovascular age-related macular degeneration: Caucasians vs Chinese

PURPOSE

To investigate the correlation between morphological features of choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD) in the first eye and the severity of age-related maculopathy (ARM) in the fellow eyes in two racial groups: Caucasians and Chinese.

PARTICIPANTS

A total of 135, fluorescein angiograms of patients with unilateral neovascular AMD and ARM in the fellow eyes were included in the study: 38 Caucasians from King's College Hospital, UK; 45 Caucasians from West Kent Eye Centre, UK; 52 Chinese from Hong Kong Eye Hospital, Hong Kong.

MAIN OUTCOME MEASURES

CNV subtype in the affected eye and ARM severity in the second eyes.

RESULTS

Although the proportion of CNV subtypes in the three groups were similar, the Chinese cohort showed significantly less ARM severity compared to the Caucasian cohorts (P < 0.05).

CONCLUSION

Although drusen and retinal pigmentary changes may be prognostic indicators of CNV, this study suggest that other factors contribute significantly to the pathogenesis of CNV in AMD.

Optimal digital filtering for tremor suppression

Remote manually operated tasks such as those found in teleoperation, virtual reality, or joystick-based computer access, require the generation of an intermediate electrical signal which is transmitted to the controlled subsystem (robot arm, virtual environment, or a cursor in a computer screen). When human movements are distorted, for instance, by tremor, performance can be improved by digitally filtering the intermediate signal before it reaches the controlled device. This paper introduces a novel tremor filtering framework in which digital equalizers are optimally designed through pursuit tracking task experiments. Due to inherent properties of the man-machine system, the design of tremor suppression equalizers presents two serious problems: 1) performance criteria leading to optimizations that minimize mean-squared error are not efficient for tremor elimination and 2) movement signals show ill-conditioned autocorrelation matrices, which often result in useless or unstable solutions. To address these problems, a new performance indicator in the context of tremor is introduced, and the optimal equalizer according to this new criterion is developed. Ill-conditioning of the autocorrelation matrix is overcome using a novel method which we call pulled-optimization. Experiments performed with artificially induced vibrations and a subject with Parkinson's disease show significant improvement in performance. Additional results, along with MATLAB source code of the algorithms, and a customizable demo for PC joysticks, are available on the Internet at http:¿tremor-suppression.com.

Symposium on asthma disease management: the role of the asthma expert: a view from Mexico

In Mexico, no effort has been made to estimate a nationwide prevalence rate of asthma. However, in the last 10 years several local studies have been carried out that analyze the same age cohort that have similar methodological features, enabling us to have a reference from which to look at childhood asthma prevalence in Mexico. Applying statistical analysis to all the surveys, we obtained a prevalence rate of childhood asthma of 11.85% with a confidence interval of 11.32% and 12.38%. We have data that let us know that the prevalence of asthma in México is increasing as in other countries. The comportment of asthma medication is changing very slowly, at least in the commercial market.

Plasma norepinephrine, myocardial damage and left ventricular systolic function in Chagas' heart disease

The functional status of the sympathetic nervous system in Chagas' heart disease is still the subject of intense controversy. To determine the nature of the abnormalities of the sympathetic nervous system, we measured the plasma norepinephrine concentration of chagasic patients with varying degrees of myocardial damage. Thirty-six patients with positive serology for Chagas' disease were studied. Twenty patients were in Functional Class I (New York Heart Association), 10 were in Functional Class II and six were in Functional Classes III-IV. Cardiac catheterization was performed in 24 patients. The asymptomatic patients had a plasma norepinephrine concentration (121 +/- 37 pg/ml, mean +/- S.D.) not different from normal controls (103 +/- 59 pg/ml). The symptomatic patients, however, had a significantly elevated plasma norepinephrine concentration (665 +/- 354 pg/ml, P < 0.001). The baseline heart rate of the asymptomatic and symptomatic patients directly correlated with the plasma norepinephrine concentration (r = 0.69, P < 0.0001). The symptomatic patients had larger ventricular volumes, higher left ventricular end-diastolic pressures and lower ejection fractions than the asymptomatic patients and normal controls. The plasma norepinephrine concentration correlated linearly with the left ventricular end-diastolic volume (r = 0.77, P < 0.0001), and non-linearly with the ejection fraction (r = -0.70, P < 0.0001) and the left ventricular end-diastolic pressure (r = 0.53, P < 0.007). These results indicate that, in Chagas' heart disease as in most other cardiac diseases, sympathetic nervous system activation is a late and compensatory phenomenon. In other words, sympathetic activation is very likely related to the progressive impairment of left ventricular function.

Illegal immigration in the presence of labor unions

"This paper develops a general equilibrium framework of a two-sector economy which incorporates illegal immigration in the presence of labor unions. It demonstrates that stricter enforcement of immigration laws, by reducing the demand for or supply of illegal aliens, benefits all legal workers in the economy. The model is used to evaluate the impact of these policy changes on national income. Results indicate that national income does not necessarily fall when immigration controls are tightened. The existence of a union mitigates the negative welfare impact of a reduction in the number of illegal immigrants."

Aggressive angiomyxoma in men. A report of two cases associated with inguinal hernias

Aggressive angiomyxoma is a rare, locally invasive, but nonmetastasizing soft-tissue tumor that most commonly occurs in the pelvis or perineum of premenopausal women. In this article, we report two cases of aggressive angiomyxoma that occurred in middle-aged men. Although both patients initially presented with inguinal hernias, in other respects the two cases were significantly different. In one case, the tumor was small and found only incidentally at the time of surgery. In the other case, the tumor was extremely large, primarily involved the scrotal soft tissue, and was clinically thought to represent a testicular tumor.

Stromal osteoclast-like giant cells in an adenosquamous carcinoma of the gallbladder

We report a case an adenosquamous carcinoma of the gallbladder that extended to the proximal transverse colon. Metastatic tumor was present in regional lymph nodes and the liver. Microscopically, the tumor was composed of malignant epithelial cells that were cytokeratin-, epithelial membrane antigen-, and carcinoembryonic antigen-positive. The adjacent desmoplastic stroma of the primary tumor, as well as the metastasis, contained giant cells that morphologically resembled osteoclasts. Immunohistochemical studies showed that the giant cells were cytokeratin-, epithelial membrane antigen-, and carcinoembryonic antigen-negative but weakly alpha 1-antichymotrypsin-positive. While tumors containing osteoclast-like giant cells have been described in the breast, lung, liver, and thyroid, this is the first report of a tumor with this morphology originating in the gallbladder. The presence of the giant cells adjacent to both the primary and metastatic tumor and not at any other location suggests that the tumor cells are producing a substance that induces the formation of the nontumoral giant cells.

Morphologic findings in bone marrow precursor cells in zinc-induced copper deficiency anemia

Damage to the bone marrow elements, as shown by cytoplasmic vacuolization, has been reported in patients with acute alcohol intoxication, drug reactions, nutritional deficiencies, myeloproliferative syndromes, malignant hematologic conditions, some metabolic conditions, and in those treated with chemotherapeutic agents. A case of zinc toxicity with anemia, leukopenia, and cytoplasmic vacuolization of both myeloid and erythroid precursors is described. The patient described was a 30-year-old quadriplegic man who was receiving oral zinc to promote the healing of and prevention of decubitus ulcers. In the gut, dietary zinc interacts with copper in a competitive manner, and high levels of zinc can lead to copper deficiency. Zinc-induced copper deficiency anemia can be morphologically identified in the bone marrow preparations by cytoplasmic vacuolization of both myeloid and erythroid precursor elements.

Relationship between c-erbB-2 immunoreactivity and thymidine labelling index in breast carcinoma in situ

The relationship between the presence of the c-erbB-2 protein, demonstrated immunohistochemically with antibody 21N, and thymidine labelling index (TLI) has been studied in the in situ component of 70 cases of carcinoma of the breast. A significant association was found between high TLI and positive staining. Twenty of the 70 cases stained (29%) and of those that were stained 75% had a high TLI; 43% of those with a high TLI stained positively but only 14% of those with a low TLI stained positively. Strong correlations were seen between nuclear size and histological pattern and both 21N staining and TLI. The majority of carcinomas of comedo pattern with large nuclei were 21N positive and had a high TLI, whilst those with small nuclei and a predominantly cribriform/micropapillary appearance did not stain and had a low TLI. In tumours of mixed histological pattern there was less concordance between staining and TLI. The significance of these findings in relation to the biological behaviour of these tumours and their clinical management is discussed.

Reactive eosinophilic pleuritis. A sequela of pneumothorax in pulmonary eosinophilic granuloma

Pneumothorax is a frequent complication of pulmonary eosinophilic granuloma (EG) and can be a presenting manifestation of this disorder. Histologically the differential diagnosis of EG in patients presenting with pneumothorax includes reactive eosinophilic pleuritis (REP), a nonspecific inflammatory reaction commonly observed in association with ruptured pleural blebs. The authors present a case in which both EG and REP were found in lung tissue from a patient with recurrent pneumothorax. Immunohistochemical stains for lysozyme and S-100 protein assisted in differentiating these two lesions. Histiocytic cells in areas of EG were S-100 positive and lysozyme negative, whereas mononuclear cells in areas of REP were S-100 negative and lysozyme positive. It is emphasized that the finding of REP and pleural blebs in lung tissue from patients presenting with pneumothorax does not exclude the diagnosis of EG.

Flow cytometric analysis of breast needle aspirates

This study investigated two hypotheses: (1) sufficient cells may be obtained by needle aspiration of breast nodules to produce good flow cytometric DNA profiles; and (2) benign breast lesions do not produce aneuploid G0G1 peaks, and therefore a distinct aneuploid peak is sufficient for a diagnosis of malignancy. Breast specimens received in Surgical Pathology between December 1985 and February 1987 were aspirated, and the cells stained with propidium iodide for flow cytometric DNA analysis. A total of 344 specimens were aspirated, of which 204 (59%) were malignant and 140 (41%) benign. One hundred fifty-three malignant and 111 benign specimens contained sufficient cells for analysis. Cytologic smears were available for 177 malignant and 123 benign specimens. DNA histograms were considered diagnostic of malignancy if an aneuploid peak was present which contained at least 20% of the cells in the distribution, and had a DNA index greater than or equal to 1.2. Using these criteria, 73 of 153 (48%) carcinomas could be identified. None of the benign lesions satisfied these criteria. One fibroadenoma with atypical hyperplasia produced a distinct peak which contained less than 5% of the cells in the histogram, and had a DNA index of 1.25. Flow cytometric analysis provides objective data that complement the subjective cytologic interpretation of fine needle aspirates.

Pituitary gland growth during normal pregnancy: an in vivo study using magnetic resonance imaging

PURPOSE

Autopsy studies have shown that pregnancy results in physiologic pituitary enlargement. We used magnetic resonance imaging (MRI) to corroborate those findings in vivo.

PATIENTS AND METHODS

Based on gestational age, 32 normal primigravid patients were divided into three groups: Group I (n = 10), less than 12 gestational weeks; Group II (n = 11), 13 to 26 gestational weeks; and Group III (n = 11), 27 gestational weeks or more. The pituitary dimensions and volumes in these groups were compared with those in 20 healthy nulliparous women (control group).

RESULTS

MRI measurements showed a significant increase in pituitary volume in Groups I, II, and III when compared with the control group (p less than 0.001). Furthermore, there was an increase in pituitary volume between Groups I and II and between Groups II and III, although the former was not statistically significant (p greater than 0.05). At the end of pregnancy, the hypophysis had increased 2.6 mm in vertical, anteroposterior, and transversal dimensions, with an overall increase of 136 percent when compared with that of the control group.

CONCLUSION

Baseline measurements of the normal enlargement of the pituitary gland that occurs during pregnancy could prove useful when evaluating pregnant patients with suspected pituitary tumors or lymphocytic hypophysitis.

CT findings in gastrointestinal perforation by ingested fish bones

Preoperative diagnosis of complications due to foreign bodies in the gastrointestinal tract is uncommon by conventional radiographic methods. We present two cases of gastric and duodenal perforation secondary to fish bone ingestion, diagnosed preoperatively by CT.

Synovial metaplasia of the skin

Synovial metaplasia has been described in bone or soft tissues following surgical procedures or under experimental conditions. Three cases in which skin biopsies showed synovial metaplasia of the dermis are herein reported. The metaplastic foci were associated with cyst formation and transepidermal fistulae. All patients had a history of previous surgical procedures in the area, and in all, the lesions clinically resembled suture granulomas. Microscopically, the lesions bore a striking resemblance to hyperplastic synovium. The immunohistochemical studies showed strong staining with vimentin and scattered positivity with alpha-1-antichymotrypsin (alpha-1ACT) and lysozyme. No basement membrane antigens or elastic fibers were demonstrated. We believe that the name "metaplastic synovial cyst" is an appropriate pathologic designation for this entity. An increased awareness of its occurrence will help to establish its true incidence.

Giant cell lichenoid dermatitis

A case of drug-induced lichenoid dermatitis with an unusual epidermotropic multinucleated giant cell inflammatory response is reported. The patient is a 52-year-old white woman who is steroid-dependent because of long-standing systemic lupus erythematosus. At the time of presentation of her generalized papulosquamous pruritic eruption, she was taking oral antihypertensive medications (methyldopa and chlorothiazide). After discontinuation of these medications and local treatment with topical corticosteroids, the skin eruption dramatically improved. Microscopically, the skin lesions had a lichenoid inflammatory pattern, with multiple cytoid bodies, multinucleated giant cells, and a mixed chronic inflammatory infiltrate that included lymphocytes, histiocytes, and eosinophils.

Chuchuhuasha - a drug used in folk medicine in the Amazonian and Andean areas. A chemical study of Maytenus laevis

In the high Amazonian basin a plant named chuchuasha, (or chuchuaso) is used in traditional medicine for several purposes in the form of an alcoholic extract. This plant, a Maytenus species, most probably Maytenus laevis, grows in the subandean region of the Amazonian basin (Peru, Ecuador, Colombia). Antitumor and anti-inflammatory properties were recently attributed to the extracts of the root bark of the plant. The composition of the extract of M. laevis from the Putumayo area of Colombia was studied in order to establish the active principle responsible for these activities. The presence of phenoldienones (tingenone, 22-hydroxytingenone), a catechin (4'-methyl-(-)-epigallocatechin) and proanthocyanidins (Ouratea-proanthocyanidins A and B) was established. The biological activities of these compounds confirm the properties of the extracts of the plant claimed by traditional medicine.