Observation of excited Λ(b)(0) baryons

Using pp collision data corresponding to 1.0 fb(-1) integrated luminosity collected by the LHCb detector, two narrow states are observed in the Λ(b)(0)π(+)π(-) spectrum with masses 5911.97±0.12(stat)±0.02(syst)±0.66(Λ(b)(0) mass) MeV/c(2) and 5919.77±0.08(stat)±0.02(syst)±0.66(Λ(b)(0) mass) MeV/c(2). The significances of the observations are 5.2 and 10.2 standard deviations, respectively. These states are interpreted as the orbitally excited Λ(b)(0) baryons, Λ(b)(*0)(5912) and Λ(b)(*0)(5920).

Measurement of the B¯(s)(0) effective lifetime in the J/ψf0(980) final state

The effective lifetime of the B ¯(s)(0) meson in the decay mode B¯(s)(0)→J/ψf(0)(980) is measured using 1.0 fb(-1) of data collected in pp collisions at √s=7 TeV with the LHCb detector. The result is 1.700±0.040±0.026 ps, where the first uncertainty is statistical and the second systematic. As the final state is CP-odd, and CP violation in this mode is measured to be small, the lifetime measurement can be translated into a measurement of the decay width of the heavy B¯(s)(0) mass eigenstate, Γ(H)=0.588±0.014±0.009 ps(-1).

Observation of B0→D¯(0)K(+)K(-) and evidence for B(s)(0)→D¯(0)K(+)K(-)

The first observation of the decay B0→D¯(0)K(+)K(-) is reported from an analysis of 0.62 fb(-1) of pp collision data collected with the LHCb detector. Its branching fraction is measured relative to that of the topologically similar decay B(0)→D ¯(0)π(+)π(-) to be (B(B(0)→D¯(0)K(+)K(-))/B(B(0)→D¯(0)π(+)π(-))=0.056±0.011±0.007,where the first uncertainty is statistical and the second is systematic. The significance of the signal is 5.8σ. Evidence, with 3.8σ significance, for B(s)(0)→D¯(0)K(+)K(-) decays is also presented. The relative branching fraction is measured to be B(B(s)(0)→D¯(0)K(+)K(-))/B(B(0)→D¯(0)K(+)K(-))=0.90±0.27±0.20. These channels are of interest to study the mechanisms behind hadronic B decays, and open new possibilities for CP violation analyses with larger data sets.

Measurement of relative branching fractions of B decays to ψ(2S) and J/ψ mesons

The relative rates of B-meson decays into J/ψ and ψ(2S) mesons are measured for the three decay modes in pp collisions recorded with the LHCb detector. The ratios of branching fractions ([Formula: see text]) are measured to be [Formula: see text] where the third uncertainty is from the ratio of the ψ(2S) and J/ψ branching fractions to μ⁺μ^-.

Measurement of ψ(2S) meson production in pp collisions at [Formula: see text]

The differential cross-section for the inclusive production of ψ(2S) mesons in pp collisions at [Formula: see text] has been measured with the LHCb detector. The data sample corresponds to an integrated luminosity of 36 pb^-1. The ψ(2S) mesons are reconstructed in the decay channels ψ(2S)→μ⁺μ^- and ψ(2S)→J/ψπ⁺π^-, with the J/ψ meson decaying into two muons. Results are presented both for promptly produced ψ(2S) mesons and for those originating from b-hadron decays. In the kinematic range p_T(ψ(2S))≤16 GeV/c and 2<y(ψ(2S))≤4.5 we measure [Formula: see text] where the last uncertainty on the prompt cross-section is due to the unknown ψ(2S) polarization. Recent QCD calculations are found to be in good agreement with our measurements. Combining the present result with the LHCb J/ψ measurements we determine the inclusive branching fraction [Formula: see text] where the last uncertainty is due to the [Formula: see text], [Formula: see text] and [Formula: see text] branching fraction uncertainties.

Search for charged Higgs bosons in e+e- collisions at [Formula: see text]

A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at [Formula: see text], corresponding to an integrated luminosity of approximately 600 pb-1. Charged Higgs bosons are assumed to be pair-produced and to decay into [Formula: see text], τντ or AW±. No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are derived by combining these results with previous searches at lower energies. Under the assumption [Formula: see text], motivated by general 2HDM type II models, excluded areas on the [Formula: see text] plane are presented and charged Higgs bosons are excluded up to a mass of 76.3 GeV at 95 % confidence level, independent of the branching ratio BR(H±→τντ ). A scan of the 2HDM type I model parameter space is performed and limits on the Higgs-boson masses [Formula: see text] and mA are presented for different choices of tanβ.

First observation of the decay B(c)+ → J/ψπ(+) π- π+

The decay B(c)(+) → J/ψπ(+) π(-) π(+) is observed for the first time, using 0.8 fb(-1) of pp collisions at sqrt[s] = 7 TeV collected by the LHCb experiment. The ratio of branching fractions B(B(c)(+) → J/ψπ(+) π(-) π(+))/B(B(c)(+)→J/ψπ^{+}) is measured to be 2.41 ± 0.30 ± 0.33, where the first uncertainty is statistical and the second is systematic. The result is in agreement with theoretical predictions.

Determination of the sign of the decay width difference in the B(s)(0) system

The interference between the K+ K- S-wave and P-wave amplitudes in B(s)(0) → J/ψK+ K- decays with the K+ K- pairs in the region around the ϕ(1020) resonance is used to determine the variation of the difference of the strong phase between these amplitudes as a function of K+ K- invariant mass. Combined with the results from our CP asymmetry measurement in B(s)(0) → J/ψϕ decays, we conclude that the B(s)(0) mass eigenstate that is almost CP = +1 is lighter and decays faster than the mass eigenstate that is almost CP = -1. This determines the sign of the decay width difference ΔΓ(s) ≡ Γ(L) - Γ(H) to be positive. Our result also resolves the ambiguity in the past measurements of the CP violating phase ϕ(s) to be close to zero rather than π. These conclusions are in agreement with the standard model expectations.

Strong constraints on the rare decays B(s)(0) → μ+ μ- and B0 → μ+ μ-

A search for B(s)(0) → μ+ μ- and B0 → μ+ μ decays is performed using 1.0  fb(-1) of pp collision data collected at sqrt[s] = 7  TeV with the LHCb experiment at the Large Hadron Collider. For both decays, the number of observed events is consistent with expectation from background and standard model signal predictions. Upper limits on the branching fractions are determined to be B(B(s)(0) → μ+ μ-) < 4.5(3.8)×10(-9) and B(B0 → μ+ μ-) < 1.0(0.81)×10(-9) at 95% (90%) confidence level.

Opposite-side flavour tagging of B mesons at the LHCb experiment

The calibration and performance of the opposite-side flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B⁺→J/ψK⁺, B⁰→J/ψK^∗0 and B⁰→D^∗-μ⁺ν_μ decay modes with 0.37 fb^-1 of data collected in pp collisions at [Formula: see text] during the 2011 physics run. The opposite-side tagging power is determined in the B⁺→J/ψK⁺ channel to be (2.10±0.08±0.24) %, where the first uncertainty is statistical and the second is systematic.

Measurement of production in collisions at [Formula: see text]

The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons in proton-proton collisions at the centre-of-mass energy of [Formula: see text] is studied with the LHCb detector. The analysis is based on a data sample of 25 pb-1 collected at the Large Hadron Collider. The ϒ mesons are reconstructed in the decay mode ϒ→μ+μ- and the signal yields are extracted from a fit to the μ+μ- invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the ϒ transverse momentum pT and rapidity y, over the range pT <15 GeV/c and 2.0 Collapse

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First evidence of direct CP violation in charmless two-body decays of Bs0 mesons

Using a data sample corresponding to an integrated luminosity of 0.35  fb-1 collected by LHCb in 2011, we report the first evidence of CP violation in the decays of Bs0} mesons to K±π∓ pairs, ACP(Bs0→Kπ)=0.27±0.08(stat)±0.02(syst), with a significance of 3.3σ. Furthermore, we report the most precise measurement of CP violation in the decays of B0 mesons to K±π∓ pairs, ACP(B0→Kπ)=-0.088±0.011(stat)±0.008(syst), with a significance exceeding 6σ.

Differential branching fraction and angular analysis of the decay B0 → K*0 μ+ μ-

The angular distributions and the partial branching fraction of the decay B0 → K*0 μ+ μ- are studied by using an integrated luminosity of 0.37  fb(-1) of data collected with the LHCb detector. The forward-backward asymmetry of the muons, A(FB), the fraction of longitudinal polarization, F(L), and the partial branching fraction dB/dq2 are determined as a function of the dimuon invariant mass. The measurements are in good agreement with the standard model predictions and are the most precise to date. In the dimuon invariant mass squared range 1.00-6.00  GeV2/c4, the results are A(FB)=-0.06(-0.14)(+0.13)±0.04, F(L)=0.55±0.10±0.03, and dB/dq2=(0.42±0.06±0.03)×10(-7)  c4/GeV2. In each case, the first error is statistical and the second systematic.

First observation of the decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-)

First observations of the Cabibbo-suppressed decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-) are reported using 35 pb(-1) of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo-favored decays, from which we obtain B(B(0) → D(+)K(-)π(+)π(-))/B(B(0) → D(+)π(-)π(+)π(-))=(5.9±1.1±0.5)×10(-2) and B(B(-) → D(0)K(-)π(+)π(-))/B(B(-) → D(0)π(-)π(+)π(-))=(9.4±1.3±0.9)×10(-2), where the uncertainties are statistical and systematic, respectively. The B(-) → D(0)K(-)π(+)π(-) decay is particularly interesting, as it can be used in a similar way to B(-) → D(0)K(-) to measure the Cabibbo-Kobayashi-Maskawa phase γ.

Observation of B(s)(0) → J/ψf(2)'(1525) in J/ψK+ K- final states

The decay B(s)(0) → J/ψK+ K- is investigated using 0.16  fb(-1) of data collected with the LHCb detector using 7 TeV pp collisions. Although the J/ψϕ channel is well known, final states at higher K+ K- masses have not previously been studied. In the K+ K- mass spectrum we observe a significant signal in the f(2)'(1525) region as well as a nonresonant component. After subtracting the nonresonant component, we find B(B(s)(0) → J/ψf(2)'(1525))/B(B(s)(0) → J/ψϕ) = (26.4 ± 2.7 ± 2.4)%.

Evidence for CP violation in time-integrated D0→h(-)h(+) decay rates

A search for time-integrated CP violation in D(0)→h(-)h(+) (h=K, π) decays is presented using 0.62 fb(-1) of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the D(*+)→D(0)π(+) and D(*-)→D[over ¯](0)π(-) decay chains. The difference in CP asymmetry between D(0)→K(-)K(+) and D(0)→π(-)π(+), ΔA(CP)≡A(CP)(K(-)K(+))-A(CP)(π(-)π(+)), is measured to be [-0.82±0.21(stat)±0.11(syst)]%. This differs from the hypothesis of CP conservation by 3.5 standard deviations.

Search for lepton number violating decays B+ → π- μ+ μ+ and B+ → K- μ+ μ+

A search is performed for the lepton number violating decay B+ → h- μ+ μ+, where h- represents a K- or a π-, using an integrated luminosity of 36  pb(-1) of data collected with the LHCb detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B(B+ → K- μ+ μ+) < 5.4×10(-8) and B(B+ → π- μ+ μ+) < 5.8×10(-8) are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.

Measurement of the CP-violating phase ϕ(s) in the decay B(s)(0) → J/ψϕ

We present a measurement of the time-dependent CP-violating asymmetry in B(s)(0) → J/ψϕ decays, using data collected with the LHCb detector at the LHC. The decay time distribution of B(s)(0) → J/ψϕ is characterized by the decay widths Γ(H) and Γ(L) of the heavy and light mass eigenstates, respectively, of the B(s)(0) - B(s)(0) system and by a CP-violating phase ϕ(s). In a sample of about 8500 B(s)(0) → J/ψϕ events isolated from 0.37  fb(-1) of pp collisions at sqrt[s] = 7  TeV, we measure ϕ(s) = 0.15 ± 0.18(stat) ± 0.06(syst)  rad. We also find an average B(s)(0) decay width Γ(s) ≡ (Γ(L) + Γ(H))/2 = 0.657 ± 0.009(stat) ± 0.008(syst)  ps(-1) and a decay width difference ΔΓ(s) ≡ Γ(L) - Γ(H) = 0.123 ± 0.029(stat) ± 0.011(syst)  ps(-1). Our measurement is insensitive to the transformation (ϕ(s),ΔΓ(s)) ↦ (π - ϕ(s), -ΔΓ(s)).

Danish heart patients’ participation in and experience with rehabilitation

Aim: This study investigated the proportion of Danish patients in cardiac therapy for ischaemic heart disease who participated in cardiac rehabilitation. The study examined differences in patients’ participation in and experience and satisfaction with cardiac rehabilitation. Methods: Data were obtained from a postal questionnaire in a representative sample of patients in therapy for an ischaemic heart disease. Response data were tabulated and analysed by logistic regression. Results: 3% of the patients participated in a complete rehabilitation programme according to Danish standards, 47% of the patients participated in a partial rehabilitation programme, and additionally 32% of the patients participated in a very limited rehabilitation programme. The number of patients participating in a complete rehabilitation programme was low due to the fact that only few patients (and their relatives) received psychological support. The factors living alone and low education are associated with low participation and in particular with receiving psychological support. Elderly (≥50 years) and male patients showed higher satisfaction scores. Patients receiving psychosocial elements in their rehabilitation programme reported higher satisfaction with their rehabilitation. Conclusions: Few Danish patients with ischaemic heart disease participate in a complete rehabilitation programme mainly due to psychosocial elements not yet being an integral part of cardiac rehabilitation in Denmark. There is a need to differentiate and tailor cardiac rehabilitation to different patient segments, e.g. by gender and age.

Fast reconstruction in magnetic particle imaging

Magnetic particle imaging (MPI) is a new tomographic imaging method which is able to capture the fast dynamic behavior of magnetic tracer material. From measured induced signals, the unknown magnetic particle concentration is reconstructed using a previously determined system function, which describes the relation between particle position and signal response. After discretization, the system function is represented by a matrix, whose size can prohibit the use of direct solvers for matrix inversion to reconstruct the image. In this paper, we present a new reconstruction approach, which combines efficient compression techniques and iterative reconstruction solvers. The data compression is based on orthogonal transforms, which extract the most relevant information from the system function matrix by thresholding, such that any iterative solver is strongly accelerated. The effect of the compression with respect to memory requirements, computational complexity and image quality is investigated. With the proposed method, it is possible to achieve real-time reconstruction with almost no loss in image quality using measured 4D MPI data.

Determination of f(s)/f(d) for 7 TeV pp collisions and measurement of the B0→D-K+ branching fraction

The relative abundance of the three decay modes B(0)→D(-)K(+), B(0)→D(-)π(+), and B(s)(0)→D(s)(-)π(+) produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb(-1). The branching fraction of B(0)→D(-)K(+) is found to be B(B(0)→D(-)K(+)) = (2.01 ± 0.18(stat) ± 0.14(syst)) × 10(-4). The ratio of fragmentation fractions f(s)/f(d) is determined through the relative abundance of B(s)(0)→D(s)(-)π(+) to B(0)→D(-)K(+) and B(0)→D(-)π(+), leading to f(s)/f(d) = 0.253 ± 0.017 ± 0.017 ± 0.020, where the uncertainties are statistical, systematic, and theoretical, respectively.

Numerical simulation of electronic properties of coupled quantum dots on wetting layers

Self-assembled quantum dots are grown on wetting layers and frequently in an array-like assembly of many similar but not exactly equal dots. Nevertheless, most simulations disregard these structural conditions and restrict themselves to simulating a pure single quantum dot. For reasons of numerical efficiency we advocate the effective one-band Hamiltonian with energy- and position-dependent effective mass approximation and a finite height hard-wall 3D confinement potential for computation of the energy levels of the electrons in the conduction band. Within this model we investigate the geometrical effects mentioned above on the electronic structure of a pyramidal InAs quantum dot embedded in a GaAs matrix. We find that the presence of a wetting layer may affect the electronic structure noticeably. Furthermore, we establish that, in spite of the large bandgap of the InAs/GaAs heterostructure, if the dots in a vertically aligned array are sufficiently close stacked there is considerable interaction between their eigenfunctions. Moreover, the eigenfunctions of such an array are quite sensitive to certain structural perturbations.

?The fungal jungle?

The World Wide Web offers an enormous variety of information about medical mycology. To go through the "fungal jungle" and find the website containing the information that is needed requires a great deal of effort and a lot of time. This article provides help in finding information about medical mycology and describes the contents of preselected websites in German and English. These pages address physicians, scientists, and students interested in dermato-mycology. Most of the pages also contain information about mycoses relevant to other medical specialties.

Comparative genomics of Listeria species

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

Two long homologous retroviral sequence blocks in proximal Yq11 cause AZFa microdeletions as a result of intrachromosomal recombination events

We mapped the breakpoints of the AZoospermia factor a (AZFa) microdeletion located in proximal Yq11 in six men with complete germ cell aplasia, i.e. Sertoli Cell Only syndrome (SCO). The proximal breakpoints were identified in a long retroviral sequence block (HERV15yq1: 9747 nucleotides) at the 5' end of the DYS11 DNA locus in Yq11, interval D3. The distal breakpoints were found in a homologous HERV15 sequence block mapped to the Yq11 interval D6, i.e. in the distal part of the AZFa region (HERV15yq2: 9969 nucleotides). Compared with the HERV15yq1 sequence, HERV15yq2 is marked by a deletion of a HERV15 sequence domain at its 5' end and insertion of an LINE 1 3'-UTR sequence block (L1PA4) of similar length at its 3' end. The deletion of the L1PA4 element was recognized as the molecular origin of the DYS11 12f2 restriction fragment length polymorphism. For all six AZFa patients it was possible to perform PCR experiments bridging both retroviral sequence blocks, which map in a distance of 781.557 kb in proximal Yq11 in fertile men. The AZFa breakpoint-fusion regions were located in their recombined HERV15yq1/HERV15yq2 sequence blocks in either one of two long identical sequence domains (ID1 and ID2). We therefore assume that intrachromosomal recombination events between the two homologous retroviral sequence blocks in proximal Yq11 are probably the causative agents for most of the AZFa microdeletions observed in men with SCO syndrome. A mean value of 792 kb was estimated for their molecular lengths.

Optimization of the hydroxylation of 2-cyclopentylbenzoxazole with Cunninghamella blakesleeana DSMZ 1906

Biohydroxylation of 2-cyclopentyl-1,3-benzoxazole with the filamentous fungus Cunninghamella blakesleeana DSMZ 1906 was studied in a 15-l stirred tank reactor. The aim of the work was to avoid substrate limitation through sub-optimal mixing by formation of pellets with a uniform pellet size distribution of 250-500 microm, obtained at an inoculum concentration of 10(7) spores ml(-1) and an agitation rate of 390 rpm. Due to the high toxicity of the educt, 2-cyclopentyl-1,3-benzoxazole, on the fungus, the medium composition, the time of educt addition, and the educt starting concentration were optimized to reach high educt tolerance and hydroxylation activity. A good maintenance of biotransformation capacity was obtained without excessive loss of activity of the biocatalyst by addition of 30 mg 2-cyclopentyl-1,3-benzoxazole/g biomass (cell dry mass) during the stationary phase in a medium which was optimized in batch fermentations with experimental designs. An increase in product yield and quality (enantiomeric excess) was achieved by developing feeding strategies combining the educt and medium components. The resulting fermentation broth contained 450 mg l(-1) of the product (1S,3S)-3-(benz-1,3-oxazol-2-yl)cyclopentan-1-ol with an enantiomeric excess of 95%, which represents a 48% increase over former reported results.

Cognitive processing is involved in cluster headache but not in chronic paroxysmal hemicrania

BACKGROUND

Cognitive processing in migraine is characterized by a loss of habituation during the interval and increased latencies in an attack. No studies are available on event-related potentials (ERPs) in cluster headache or chronic paroxysmal hemicrania.

OBJECTIVE

To determine the involvement of cognitive processing in cluster headache and chronic paroxysmal hemicrania as measured by ERPs.

METHODS

Visually evoked ERPs were measured in 50 patients with episodic cluster headache, 11 patients with chronic cluster headache, and 12 patients with chronic paroxysmal hemicrania. Measurements were performed in the cluster period outside an attack with and without prophylactic medication and not in the cluster period.

RESULTS

Latencies of the endogenous ERP components were significantly increased during the cluster period as compared with outside the cluster period and with healthy subjects. In chronic cluster headache, latencies of both endogenous and exogenous components were increased. Medication with prophylactic drugs normalized the ERP latencies in episodic cluster headache; in chronic cluster headache, ERP latencies were decreased without complete normalization. No changes of ERP latencies and amplitudes could be observed in chronic paroxysmal hemicrania. A loss of cognitive habituation as it is known in migraine could not be observed in either cluster headache or chronic paroxysmal hemicrania.

CONCLUSIONS

Our data suggest that central structures generating ERPs are involved in the pathophysiology of cluster headache during the cluster period but not outside the cluster period. This is in concordance with recent neuroimaging findings on the central role of the hypothalamus and the right frontal cortex in cluster headache and supports the hypothesis of a central origin of cluster headache. Furthermore, the data suggest that cluster headache and chronic paroxysmal hemicrania are distinct entities.

The impact of ergotamine-induced headache and ergotamine withdrawal on information processing

Ergotamine abuse and subsequent ergotamine-induced headache is a common problem in the pharmacological treatment of migraine and other headache types; often, withdrawal therapy is necessary. This study investigated whether ergotamine abuse affects information processing and whether withdrawal therapy can lead to an improvement of information processing. We designed a standardized neurophysiological retrospective (ergotamine abuse) and prospective (ergotamine withdrawal) study in a supraregional headache outpatient clinic. Seventy-one patients abusing ergotamine derivatives with subsequent daily headache were enrolled and compared to 36 migraine patients without ergotamine intake and 36 healthy subjects. Information processing was evaluated by latencies and amplitudes of visually evoked event-related potentials (ERP) before and after ergotamine withdrawal therapy. P3 latency of the ERP was significantly increased in ergotamine abuse (442 +/- 45 ms) versus migraine (415 +/- 40 ms) and healthy subjects (410 +/- 33 ms), there was no difference between ergotamine tartrate and dihydroergotamine abuse. The migraine specific loss of habituation in information processing as measured by P3 latency could not be observed in migraine patients with ergotamine abuse. After successful withdrawal therapy in 36 patients, the abnormally prolonged P3 latency was significantly shortened (452 +/- 47 ms versus 433 +/- 30 ms; P < 0.004). Our findings imply that information processing is impaired by ergotamine abuse and can be improved but not normalized after withdrawal therapy. Furthermore, our data provide strong evidence that ergotamine, besides its peripheral effects, has a central mode of action.