Caratteristiche principali dell'emissione di galassie a spirale

Lo spazio fra le stelle nelle galassie non è vuoto, ma è composto da gas rarefatto, particelle di polvere, un campo magnetico, elettroni, protoni e altri nuclei atomici relativistici; spesso questi elementi possono essere considerati come un’unica entità di- namica: il mezzo interstellare o più semplicemente ISM. Nel primo capitolo vedremo come il mezzo si distribuisce generalmente all’interno delle galassie a spirale, in fasce di temperatura sempre minore man mano che ci si allontana dal centro (HIM, WIM, WNM, CNM). La conoscenza della distribuzione del mezzo è utile per poter comprendere maggiormente i processi di emissione e le varie zone in cui questi avvengono in una tipica galassia a spirale, che è lo scopo di questa tesi. L’ISM infatti entra in gioco in quasi tutti i processi emissivi, in tutte le bande di emis- sione dello spettro elettromagnetico che andremo ad analizzare. Il nostro modo di vedere le galassie dell’universo è molto cambiato infatti nel corso dell’ultimo secolo: l’utilizzo di nuovi telescopi ci ha permesso di andare ad osservare le galassie anche in bande dello spettro diverse da quella visibile, in modo da raccogliere informazioni impossibili da ottenere con la sola banda ottica. Nel secondo capitolo andremo ad analizzare cinque bande di emissione (banda X, ot- tica, radio, gamma e infrarossa) e vedremo come appaiono tipicamente le galassie a spirale a lunghezze d’onda differenti, quali sono i processi in gioco e come il mezzo interstellare sia fondamentale in quasi ogni tipo di processo. A temperature elevate, esso è responsabile dell’emissione X della galassia, mentre re- gioni più fredde, formate da idrogeno ionizzato, sono responsabili delle righe di emis- sione presenti nello spettro ottico. Il campo magnetico, tramite le sue interazioni con elettroni relativistici è la principale fonte dell’emissione radio nel continuo di una galas- sia a spirale, mentre quella in riga è dovuta a idrogeno atomico o a gas freddo. Vedremo infine come raggi cosmici e polvere, che fanno sempre parte del mezzo inter- stellare, siano rispettivamente la causa principale dell’emissione gamma e infrarossa.

Holocene tsunami events in the Eastern Ionian Sea - Geoscientific evidence from Cefalonia and the western Peloponnese (Greece)

This study presents geo-scientific evidence for Holocene tsunami impact along the shores of the Eastern Ionian Sea. Cefalonia Island, the Gulf of Kyparissia and the Gialova Lagoon were subject of detailed geo-scientific investigations. It is well known that the coasts of the eastern Mediterranean were hit by the destructive influence of tsunamis in the past. The seismically highly active Hellenic Trench is considered as the most significant tsunami source in the Eastern Ionian Sea. This study focuses on the reconstruction and detection of sedimentary signatures of palaeotsunami events and their influence on the Holocene palaeogeographical evolution. The results of fine grained near coast geo-archives are discussed and interpreted in detail to differentiate between tsunami, storm and sea level highstands as sedimentation processes.rnA multi-method approach was applied using geomorphological, sedimentological, geochemical, geophysical and microfaunal analyses to detect Holocene tsunamigenic impact. Chronological data were based on radiocarbondatings and archaeological age estimations to reconstruct local geo-chronostratigraphies and to correlate them on supra-regional scales.rnDistinct sedimentary signatures of 5 generations of tsunami impact were found along the coasts of Cefalonia in the Livadi coastal plain. The results show that the overall coastal evolution was influenced by tsunamigenic impact that occured around 5700 cal BC (I), 4250 cal BC (II), at the beginning of the 2nd millennium cal BC (III), in the 1st millennium cal BC (IV) and posterior to 780 cal AD (V). Sea level reconstructions and the palaeogeographical evolution show that the local Holocene sea level has never been higher than at present.rnAt the former Mouria Lagoon along the Gulf of Kyparissia almost four allochtonous layers of tsunamigenic origin were identified. The stratigraphical record and palaeogeographical reconstructions show that major environmental coastal changes were linked to these extreme events. At the southern end of the Agoulenitsa Lagoon at modern Kato Samikon high-energy traces were found more than 2 km inland and upt ot 9 m above present sea level. The geo-chronological framework deciphered tsunami landfall for the 5th millennium cal BC (I), mid to late 2nd mill. BC (II), Roman times (1st cent. BC to early 4th cent. AD) (III) and most possible one of the historically well-known 365 AD or 521/551 AD tsunamis (IV).rnCoarse-grained allochthonous sediments of marine origin were found intersecting muddy deposits of the quisecent sediments of the Gialova Lagoon on the southwestern Peloponnese. Radiocarbondatings suggest 6 generations of major tsunami impact. Tsunami generations were dated to around 3300 cal BC (I), around the end of 4th and the beginning of 3rd millennium BC (II), after around 1100 cal BC (III), after the 4th to 2nd cent. BC (IV), between the 8th and early 15th cent. AD (V) and between the mid 14th to beginning of 15th cent. AD (VI). Palaeogeographical and morphological characteristics in the environs of the Gialova Lagoon were controlled by high-energy influence.rnSedimentary findings in all study areas are in good accordance to traces of tsunami events found all over the Ionian Sea. The correlation of geo-chronological data fits very well to coastal Akarnania, the western Peloponnese and finding along the coasts of southern Italy and the Aegean. Supra-regional influence of tsunamigenic impact significant for the investigated sites. The palaeogeographical evolution and palaeo-geomorphological setting of the each study area was strongly affected by tsunamigenic impact.rnThe selected geo-archives represent extraordinary sediment traps for the reconstruction of Holocene coastal evolution. Our result therefore give new insight to the exceptional high tsunami risk in the eastern Mediterranean and emphasize the underestimation of the overall tsunami hazard.

"Dalla parola all’azione": traduzione dell’introduzione al catalogo di una mostra d’arte contemporanea russa

Il presente elaborato consiste in una proposta di traduzione dell’introduzione, opera dalla curatrice Saša Obuchova, al catalogo della mostra "Performans v Rossi: kartografija istorii" [La performance in Russia: una cartografia della sua storia], tenutasi al museo d’arte contemporanea Garaž di Mosca. L’elaborato consta di tre capitoli. Il primo, di carattere generale, descrive le caratteristiche del testo che si è scelto di tradurre, presenta brevemente l’autrice, la struttura del catalogo di cui tale testo fa parte e la mostra per la quale il catalogo è stato pubblicato, e dà infine qualche cenno sulla storia del museo Garaž. Il secondo, di carattere artistico, propone una riflessione sul significato della parola “performance” e una breve sintesi della storia della performance-art in Russia. Infine, nel terzo, si troverà la traduzione del testo "Ot slova k dejstvii" [Dalla parola all’azione] della curatrice della mostra Saša Obuchova, preceduta da un’introduzione al testo e alla traduzione.

Effect of the prolactin-release inhibitor quinagolide on lactating dairy cows

In most mammals, prolactin (PRL) is essential for maintaining lactation, and yet the short-term suppression of PRL during established lactation by bromocriptine has produced inconsistent effects on milk yield in cows and goats. To assess the effect of the long-term inhibition of PRL release in lactating dairy cows, 5 Holstein cows in early lactation received daily intramuscular injections of 1mg of the PRL-release inhibitor quinagolide for 9 wk. Four control cows received the vehicle (water) only. During the last week of the treatments, one udder half was milked once a day (1x) and the other twice a day (2x). Blood samples were harvested at milking in wk -1, 1, 4, and 8. The daily injections of quinagolide reduced milking-induced PRL release but not the basal PRL concentration. Quinagolide induced a faster decline in milk production, which was about 5.3 kg/d lower in the quinagolide-treated cows during the last 4 wk of treatment. During wk 9, the inhibition of milk production by quinagolide was maintained in the udder half that was milked 2x but not in the half milked 1x. Milk production was significantly correlated with the quantity of PRL released at milking. Quinagolide did not affect the release of oxytocin at milking. Serum concentration of insulin-like growth factor-1 was not affected by treatment or correlated with milk production. Serum concentrations of leptin and the calciotropic hormone stanniocalcin were not affected by the treatment. In conclusion, the chronic administration of the PRL-release inhibitor quinagolide decreases milk production in dairy cows. The effect is likely the result of the reduced release of milking-induced PRL and is modulated at the level of the gland by milking frequency.

The Sociolinguistics of Hungarian Outside Hungary

This study describes the sociolinguistic situation of the indigenous Hungarian national minorities in Slovakia (c. 600,000), Ukraine (c. 180,000), Romania (c. 2,000,000), Yugoslavia (c. 300,000), Slovenia (c. 8,000) and Austria (c. 6,000). Following the guidelines of Hans Goebl et al, the historical sociolinguistic portrait of each minority is presented from 1920 through to the mid-1990s. Each country's report includes sections on geography and demography, history, politics, economy, culture and religion, language policy and planning, and language use (domains of minority and/or majority language use, proficiency, attitudes, etc.). The team's findings were presented in the form of 374 pages of manuscripts, articles and tables, written in Hungarian and English. The core of the team's research results lies in the results of an empirical survey designed to study the social characteristics of Hungarian-minority bilingualism in the six project countries, and the linguistic similarities and differences between the six contact varieties of Hungarian and Hungarian in Hungary. The respondents were divided by age, education, and settlement group - city vs. village and local majority vs. local minority. The first thing to be observed is that Hungarian is tending to be spoken less to children than to parents and grandparents, a familiar pattern of language shift. In contact varieties of Hungarian, analytic constructions may be used where monolingual Hungarians would use a more synthetic form. Mr Kontra gives as an example the compound tagdij, which in Standard Hungarian means "membership fee" but which is replaced in contact Hungarian by the two-word phrase tagsagi dij. Another similar example concerns the synthetic verb hegedult "played the violin" and the analytic expression hegedun jatszott. The contrast is especially striking between the Hungarians in the northern Slavic countries, who use the synthetic form frequently, and those in the southern Slavic countries, who mainly use the analytic form. Mr. Kontra notes that from a structural point of view, there is no immediate explanation for this, since Slovak or Ukrainian are as likely to cause interference as is Serbian. He postulates instead that the difference may be attributable to some sociohistoric cause, and points out that the Turkish occupation of what is today Voivodina caused a discontinuity of the Hungarian presence in the region, with the result that Hungarians were resettled in the area only two and a half centuries ago. However, the Hungarians in today's Slovakia and Ukraine have lived together with Slavic peoples continuously for over a millennium. It may be, he suggests, that 250 years of interethnic coexistence is less than is needed for such a contact-induced change to run its course. Next Mr. Kontra moved on to what he terms "mental maps and morphology". In Hungarian, the names of cities and villages take the surface case (eg. Budapest-en "in Budapest") whereas some names denoting Hungarian settlements and all names of foreign cities take the interior case (eg. Tihany-ban "in Tihany" and Boston-ban "in Boston). The role of the semantic feature "foreign" in suffix-choice can be illustrated by such minimal pairs as Velence-n "in Velence, a village in Hungary" versus Velence-ben "in Velence [=Venice], a city in Italy", and Pecs-en "in Pecs, a city in Hungary" vs. Becs-ben "in Becs, ie. Vienna". This Hungarian vs. foreign distinction is often interpreted as "belonging to historical (pre-1920) Hungary" vs. "outside historical Hungary". The distinction is also expressed in the dichotomy "home" vs. "abroad'. The 1920 border changes have had an impact on both majority and minority Hungarians' mental maps, the maps which govern the choice of surface vs. interior cases with placenames. As there is a growing divergence between the mental maps of majority and minority Hungarians, so there will be a growing divergence in their use of the placename suffixes. Two placenames were chosen to scratch the surface of this complex problem: Craiova (a city in Oltenia, Romania) and Kosovo (Hungarian Koszovo) an autonomous region in southeast Yugoslavia. The assumption to be tested was that both placenames would be used with the inessive (interior) suffixes categorically by Hungarians in Hungary, but that the superessive suffix (showing "home") would be used near-categorically by Hungarians in Romania and Yugoslavia (Voivodina). Minority Hungarians in countries other than Romania and Yugoslavia would show no difference from majority Hungarians in Hungary. In fact, the data show that, contrary to expectation, there is considerable variation within Hungary. And although Koszovo is used, as expected, with the "home" suffix by 61% of the informants in Yugoslavia, the same suffix is used by an even higher percentage of the subjects in Slovenia. Mr. Kontra's team suggests that one factor playing a role in this might be the continuance of the former Yugoslav mentality in the Hungarians of Slovenia, at least from the geographical point of view. The contact varieties of Hungarian show important grammatical differences from Hungarian in Hungary. One of these concerns the variable use of Null subjects (the inclusion or exclusion of the subject of the verb). When informants were asked to insert either megkertem or megkertem ot - "I asked her" - into a test sentence, 54.9% of the respondents in the Ukraine inserted the second phrase as opposed to only 27.4% in Hungary. Although Mr. Kontra and his team concentrated more on the differences between Contact Hungarian and Standard Hungarian, they also discovered a number of similarities. One such similarity is demonstrable in the distribution of what Mr. Kontra calls an ongoing syntactic merger in Hungarian in Hungary. This change means effectively that two possibilities merge to form a third. For instance, the two sentences Valoszinuleg kulfoldre fognak koltozni and Valoszinu, hogy kulfoldre fognak koltozni merge to form the new construction Valszinuleg, hogy kulfoldre fognak koltozni ("Probably they will move abroad."). When asked to choose "the most natural" of the sentences, one in four chose the new construction, and a chi-square test shows homogeneity in the sample. In other words, this syntactic change is spreading across the entire Hungarian-speaking region in the Carpathian Basin Mr. Kontra believes that politicians, educators, and other interested parties now have reliable and up-to-date information about each Hungarian minority. An awareness of Hungarian as a pluricentric language is being developed which elevates the status of contact varieties of Hungarian used by the minorities, an essential process, he believes, if minority languages are to be maintained.

Effects of tryptophan supplementation on plasma tryptophan and related hormone levels in heifers and dairy cows

This study was conducted to investigate the effects of rumen-protected tryptophan (125g tryptophan per day) in heifers and dairy cows. Blood samples from dairy cows and heifers were collected for 24h in 3-h intervals on the day before tryptophan supplementation, on day 2, 5 and 7 of tryptophan supplementation, and in heifers additionally on d 14 after tryptophan supplementation was ceased. Plasma tryptophan, melatonin, serotonin, and prolactin concentrations were determined. Tryptophan plasma concentrations on d 5 were augmented at day (11:00h) and nighttime (02:00h), (P<0.05) in response to tryptophan supplementation in heifers by 119% and in dairy cows by 47%, respectively, as compared with d 0. Melatonin increased (P<0.05) in response to tryptophan supplementation in heifers, but not in cows. The effect of tryptophan supplementation on plasma tryptophan and melatonin was reversible as demonstrated in heifers on d 14 after cessation of tryptophan supplementation. Serotonin and prolactin in plasma did not respond to tryptophan supplementation. However, milk yield during morning milking increased significantly in tryptophan supplemented cows on d 1, 3 and 4 as compared to the day before tryptophan supplementation. Additional blood samples were taken during afternoon milking in cows at 1-min intervals for the analyses of oxytocin and prolactin on the day before the start and on d 7 of tryptophan supplementation. Milk flow curves were recorded during milking. No effect of tryptophan supplementation on the milking related release of oxytocin and prolactin and on any characteristic of milk flow was observed. In conclusion, tryptophan supplementation caused increased plasma tryptophan in cows and heifers and plasma melatonin in heifers. However, plasma serotonin, prolactin and oxytocin release in cows remained unchanged by tryptophan supplementation. Milk yield at morning milking increased slightly and transiently in response to tryptophan supplementation.

Hypertonic NaCl infusions affect milk composition in goats

The capability of goats to maintain milk production during water deprivation is remarkable and not yet fully understood. The aim of the present study was to investigate whether intravenous infusions of hypertonic NaCl cause release of both vasopressin and oxytocin and whether the peptides, in combination with the hyperosmolality, affect milk flow and milk composition. Six Swedish domestic landrace goats in their first to third lactation were milked every 30 min during experiments. Hypertonic NaCl (HNaCl) or isotonic NaCl (IsoNaCl) were infused for 90 min. Goats were not allowed to drink during infusions. Plasma vasopressin concentration increased during HNaCl infusions, and did not change in response to IsoNaCl infusions. Plasma oxytocin concentration did not change during either infusion. Milk flow was maintained during the infusions. Milk fat concentration decreased in the three samples taken before onset of the infusions, but then increased gradually during HNaCl infusions, while it continued to fall during the IsoNaCl infusions. Milk osmolality followed the rise in plasma osmolality during the HNaCl infusions and did not change in IsoNaCl experiments. Milk lactose concentration increased throughout both series of experiments, the concentration being higher during HNaCl infusions. Milk protein concentration did not change during HNaCl infusions, but fell in the IsoNaCl experiments. It is concluded that the hyperosmolality in combination with elevated plasma vasopressin levels did not disturb the secretory activity of the mammary cells, but rather facilitated emptying of the alveolar milk. Such a mechanism may help to explain the sustained milk production in water deprived goats.

The antibody response in experimental ocular toxoplasmosis

BACKGROUND: The dynamics of the humoral immune response in ocular toxoplasmosis (OT) are poorly understood. We therefore investigated this process in a rabbit model of the disease. MATERIALS AND METHODS: Of 24 infection-naïve adult rabbits, 12 were left untreated and 12 were systematically infected with 5,000 tachyzoites of the non-cyst-forming BK strain of Toxoplasma gondii. Three months later, all rabbits were inoculated transvitreally with 5,000 tachyzoites of Toxoplasma gondii. Paired samples of aqueous humor and serum were analyzed temporally for their total and specific IgG contents. RESULTS: In infection-naïve rabbits with primary OT, specific IgG reached detectable levels in the inoculated eyes between 5 and 15 days after inoculation. In infection-immunized rabbits with secondary OT, a significant increase in specific IgG was regularly detected after 5 days. The antibody ratio C was diagnostic (>/=3) from day 15 onward in primary OT and from day 21 onward in secondary OT. In the uninfected partner eyes, the antibody ratio C was found sporadically diagnostic from day 15 onward in primary OT, but at no time in secondary OT. Specific IgG persisted both locally and in the serum until the end of the monitoring period (100 days). CONCLUSION: Our findings relating to the rabbit model of OT reveal three features of clinical relevance: a diagnostic window precedes the establishment of a humoral immune response; specific antibodies persist long after the cessation of disease activity; and in primary OT, the antibody ratio C may also increase in the uninfected partner eye.

Oral misoprostol for third stage of labor: a randomized placebo-controlled trial

OBJECTIVE: To investigate whether orally administered misoprostol during the third stage of labor is efficient in reducing postpartum blood loss. METHODS: In a double-masked trial, during vaginal delivery women were randomly assigned to receive a single oral dose of misoprostol (600 microg) or placebo in third stage of labor, immediately after cord clamping. The third stage of labor was managed routinely by early cord clamping and controlled cord traction; oxytocin was administered only if blood loss seemed more than usual. Blood loss was estimated by the delivering physician and differences in hematocrit were measured before and after delivery. RESULTS: Mean (+/- standard error of the mean) estimated blood loss (345 +/- 19.5 mL versus 417 +/- 25.9 mL, P = .031) and hematocrit difference (4.5 +/- 0.9% versus 7.9 +/- 1.2%, P = .014) were significantly lower in women who received misoprostol than those who received placebo. Fewer women in the misoprostol group had postpartum hemorrhage (blood loss of at least 500 mL), but that difference was not statistically significant (7% versus 15%, P = .43). Additional oxytocin before or after placental separation was used less often in the misoprostol group (16% versus 38%, P = .047). There were no differences in the length of third stage of labor (8 +/- 0.9 minutes versus 9 +/- 1 minutes, P = .947). There were no differences in pain during third stage of labor, postpartum fever, or diarrhea, but shivering was more frequent in the misoprostol group. CONCLUSION: Oral misoprostol administered in the third stage of labor reduced postpartum blood loss and might be effective in reducing incidence of postpartum hemorrhage.

The current and future state of interventional cardiology: a critical appraisal

After 75 years of invasive and over 50 years of interventional cardiology, cardiac catheter-based procedures have become the most frequently used interventions of modern medicine. Patients undergoing a percutaneous coronary intervention (PCI) outnumber those with coronary artery bypass surgery by a factor of 2 to 4. The default approach to PCI is the implantation of a (drug-eluting) stent, in spite of the fact that it improves the results of balloon angioplasty only in about 25% of cases. The dominance of stenting over conservative therapy or balloon angioplasty on one hand and bypass surgery on the other hand is a flagrant example of how medical research is digested an applied in real life. Apart from electrophysiological interventions, closure ot the patent foramen ovale and percutaneous replacement of the aortic valve in the elderly have the potential of becoming daily routine procedures in catheterization laboratories around the world. Stem cell regeneration of vessels or heart muscle, on the other hand, may remain a dream never to come true.

Incontinentia lactis: physiology and anatomy conducive to milk leakage in dairy cows

Incontinentia lactis is a possible predisposing factor for an elevated level of intramammary infection. The goal of the present study was to investigate possible causes of incontinentia lactis in dairy cows. Two farms that differed in breed composition, but that had similar average milk yields were studied: herd A, 28 kg/d, 31 Red Holstein cows; and herd B, 26 kg/d, 16 Brown Swiss cows. Herd A was classified into 2 groups: incontinentia lactis (ILA group) and control, whereas herd B was exclusively a control herd. Milk samples that represented foremilk and the main milk fraction were collected during 4 milking sessions. In addition, milk leakage samples from the ILA group were collected at different time intervals from 0 to 5 h before milking. Measurements of the teat, milk flow, fractions of cisternal and alveolar milk, intramammary pressure, and blood oxytocin pattern also were obtained. The ILA cows did not have differences in fat content between milk leakage and cisternal milk fraction. Milk fat content, however, increased during milking in response to continuous milk ejection (1.95, 1.99, and 4.61% for milk leakage, cisternal, and main milk samples, respectively). Teat canals were 9% shorter in the ILA cows, which showed greater milk yield, peak, and average flow rates. Quarter cisternal milk yield of ILA cows tended to be greater (0.50 vs. 0.23 and 0.28 kg for ILA and controls from herds A and B, respectively), whereas percentages of cistern milk and alveolar milk did not differ from controls. The greater pressure in the ILA group, both before and after manual udder stimulation (ILA: 4.0 and 6.4 kPa; control: 2.0 and 5.0 kPa, respectively), could be an important cause for the leakage. Nevertheless, the increase in IMP that occurred after udder preparation affirms that milk ejection occurred in response to the tactile teat stimulation, but not before the onset of leakage. Blood oxytocin concentration in ILA cows was low until the start of udder preparation and increased in response to the milking stimulus (reaffirming the hypothesis that milk leakage occurred in the absence of milk ejection). In conclusion, milk losses by leakage are likely due to the large amount of cisternal milk, which creates pressure and causes leakage, in the absence of milk ejection.

Maternal factors implicated in fetal bradycardia after combined spinal epidural for labour pain

BACKGROUND AND OBJECTIVE: Combined spinal epidural analgesia is effective for fast relief of severe labour pain but has been associated with worrisome decreases in fetal heart rate. Since the reasons for this phenomenon remain elusive, some anaesthesiologists may abstain from using this technique. We postulated that factors unrelated to the neuraxial technique could play a role in the decrease in fetal heart rate. To our knowledge, no prospective study has previously looked into this possibility. METHODS: We collected prospective data on 223 consecutive patients who received combined spinal epidural analgesia (123) or epidural analgesia (100). Maternal blood pressure, analogue pain scores, exogenous infusion of oxytocin, cervical dilatation, maternal age, parity and ethnicity were collected and correlated with the occurrence of decreases in fetal heart rate post combined spinal epidural. RESULTS: Univariate analysis showed a correlation between the incidence of fetal bradycardia and higher maternal pain scores, older maternal age, and combined spinal epidural analgesia. Multivariate analysis revealed that only pain scores and maternal age were independent predictors of fetal bradycardia post neuraxial blockade. CONCLUSIONS: Maternal pain scores and older maternal age are factors unrelated to the neuraxial technique that are independent predictors of fetal bradycardia after neuraxial analgesia for labour.

Recurrence characteristics in European patients with ocular toxoplasmosis

BACKGROUND: The risk of function loss after each episode of ocular toxoplasmosis (OT) supports efforts to improve our understanding of the disease. Patients and methods: 139 patients with OT were contacted retrospectively and requested to complete a questionnaire addressing course and activity of their disease. This information was compared with that retrieved from their medical records. Sixty-three patients completed the questionnaire and were included in the study. They were allocated according to their median age to one of two groups (group 1: <20.9 years; group 2: >or=20.9 years). RESULTS: The mean reported age at the time of first ocular manifestation was 23.9 (median 20.9, range 0 to 70.5; SD 12.9) years. The clinical diagnosis was made 3.5 years later (p = 0.0008). The follow-up time was 6.5 (median 5.0; range 0.5 to 49.9; SD 7.6) years. The recurrence rate was higher in patients below 20.9 years (66%; n = 35) than in older patients (39%; n = 28; chi(2) test, p<0.05). Patients reporting only one episode were older at first manifestation (29.6 (median 25.6; range 10.6 to 70.5; SD 14.3) years; n = 29) than those reporting two episodes (17.9 (median 19.5; range 5.9 to 33.9; SD 7.8) years; n = 15 (p<0.05)). The proportion of patients who developed a recurrence was 54-63% after each episode without a tendency to enlarge, and the interval between successive episodes remained stable between 1.0 and 1.7 years for the first three recurrences. CONCLUSION: Younger OT patients carry a higher risk of developing a recurrence than older ones. After each episode, two-thirds of all OT patients will develop another one.