Simultaneous Determination of Neutron-Induced Fission and Radiative Capture Cross Sections from Decay Probabilities Obtained with a Surrogate Reaction.

Reliable neutron-induced-reaction cross sections of unstable nuclei are essential for nuclear astrophysics and applications but their direct measurement is often impossible. The surrogate-reaction method is one of the most promising alternatives to access these cross sections. In this work, we successfully applied the surrogate-reaction method to infer for the first time both the neutron-induced fission and radiative capture cross sections of ^{239}Pu in a consistent manner from a single measurement. This was achieved by combining simultaneously measured fission and γ-emission probabilities for the ^{240}Pu(^{4}He,^{4}He^{'}) surrogate reaction with a calculation of the angular-momentum and parity distributions populated in this reaction. While other experiments measure the probabilities for some selected γ-ray transitions, we measure the γ-emission probability. This enlarges the applicability of the surrogate-reaction method.

Evidence for a New Compact Symmetric Fission Mode in Light Thorium Isotopes.

Taking benefit of the R3B/SOFIA setup to measure the mass and the nuclear charge of both fission fragments in coincidence with the total prompt-neutron multiplicity, the scission configurations are inferred along the thorium chain, from the asymmetric fission in the heavier isotopes to the symmetric fission in the neutron-deficient thorium. Against all expectations, the symmetric scission in the light thorium isotopes shows a compact configuration, which is in total contrast to what is known in the fission of the heavier thorium isotopes and heavier actinides. This new main symmetric scission mode is characterized by a significant drop in deformation energy of the fission fragments of about 19 MeV, compared to the well-known symmetric scission in the uranium-plutonium region.

First Direct Measurement of Isotopic Fission-Fragment Yields of

A direct and complete measurement of isotopic fission-fragment yields of ^{239}U has been performed for the first time. The ^{239}U fissioning system was produced with an average excitation energy of 8.3 MeV in one-neutron transfer reactions between a ^{238}U beam and a ^{9}Be target at Coulomb barrier energies. The fission fragments were detected and isotopically identified using the VAMOS++ spectrometer at the GANIL facility. The measurement allows us to directly evaluate the fission models at excitation energies of fast neutrons, which are relevant for next-generation nuclear reactors. The present data, in agreement with model calculations, do not support the recently reported anomaly in the fission-fragment yields of ^{239}U, and they confirm the persistence of spherical shell effects in the Sn region at excitation energies exceeding the fission barrier by a few mega-electron volts.

Approaching the Gamow Window with Stored Ions: Direct Measurement of

We report the first measurement of low-energy proton-capture cross sections of ^{124}Xe in a heavy-ion storage ring. ^{124}Xe^{54+} ions of five different beam energies between 5.5 and 8 AMeV were stored to collide with a windowless hydrogen target. The ^{125}Cs reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and x-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron and γ widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.

Predictors of success of high-flow nasal cannula in the treatment of acute hypoxemic respiratory failure. / Predictores de éxito del tratamiento con cánula nasal de alto flujo en el fallo respiratorio agudo hipoxémico.

BACKGROUND: High-flow nasal cannula (HFNC) therapy is used in the treatment of acute respiratory failure (ARF) and is both safe and effective in reversing hypoxemia. In order to minimize mortality and clinical complications associated to this practice, a series of tools must be developed to allow early detection of failure. The present study was carried out to: (i)examine the impact of respiratory rate (RR), peripheral oxygen saturation (SpO2), ROX index (ROXI=[SpO2/FiO2]/RR) and oxygen inspired fraction (FiO2) on the success of HFNC in patients with hypoxemic ARF; and (ii)analyze the length of stay and mortality in the ICU, and the need for mechanical ventilation (MV). METHODS: A retrospective study was carried out in the medical-surgical ICU of Hospital de Montilla (Córdoba, Spain). Patients diagnosed with hypoxemic ARF and treated with HFNC from January 2016 to January 2018 were included. RESULTS: Out of 27 patients diagnosed with ARF, 19 (70.37%) had hypoxemic ARF. Fifteen of them (78.95%) responded satisfactorily to HFNC, while four (21.05%) failed. After two hours of treatment, RR proved to be the best predictor of success (area under the ROC curve [AUROC] 0.858; 95%CI: 0.63-1.05; P=.035). For this parameter, the optimal cutoff point was 29rpm (sensitivity 75%, specificity 87%). After 8hours of treatment, FiO2 and ROXI were reliable predictors of success (FiO2: AUROC 0.95; 95%CI: 0.85-1.04; P=.007 and ROXI: AUROC 0.967; 95%CI: 0.886-1.047; P=.005). In the case of FiO2 the optimal cutoff point was 0.59 (sensitivity 75%, specificity 93%), while the best cutoff point for ROXI was 5.98 (sensitivity 100%, specificity 75%). Using a Cox regression model, we found RR<29rpm after two hours of treatment, and FiO2<0.59 and ROXI>5.98 after 8hours of treatment, to be associated with a lesser risk of MV (RR: HR 0.103; 95%CI: 0.11-0.99; P=.05; FiO2: HR 0.053; 95%CI: 0.005-0.52; P=.012; and ROXI: HR 0.077; 95%CI: 0.008-0.755; P=.028, respectively). CONCLUSIONS: RR after two hours of treatment, and FiO2 and ROXI after 8hours of treatment, were the best predictors of success of HFNC. RR<29rpm, FiO2<0.59 and ROXI>5.98 were associated with a lesser risk of MV.

The Neutrons for Science Facility at SPIRAL-2.

The neutrons for science (NFS) facility is a component of SPIRAL-2, the new superconducting linear accelerator built at GANIL in Caen (France). The proton and deuteron beams delivered by the accelerator will allow producing intense neutron fields in the 100 keV-40 MeV energy range. Continuous and quasi-mono-kinetic energy spectra, respectively, will be available at NFS, produced by the interaction of a deuteron beam on a thick Be converter and by the 7Li(p,n) reaction on thin converter. The pulsed neutron beam, with a flux up to two orders of magnitude higher than those of other existing time-of-flight facilities, will open new opportunities of experiments in fundamental research as well as in nuclear data measurements. In addition to the neutron beam, irradiation stations for neutron-, proton- and deuteron-induced reactions will be available for cross-sections measurements and for the irradiation of electronic devices or biological cells. NFS, whose first experiment is foreseen in 2018, will be a very powerful tool for physics, fundamental research as well as applications like the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors.

First experiment on fission transients in highly fissile spherical nuclei produced by fragmentation of radioactive beams.

We report on a novel experimental approach for studying the dissipative spreading of collective motion in a metastable nuclear system, using, for the first time, highly fissile nuclei with spherical shape. This was achieved by fragmentation of 45 radioactive heavy-ion beams at GSI, Darmstadt. The use of inverse kinematics and a dedicated experimental setup allowed for the identification in atomic number of both fission fragments. From the width of their nuclear-charge distributions, a transient time of (3.3+/-0.7)x10(-21) s is deduced for initially spherical nuclei.

Behaviour of health professionals concerning the recommendations for prophylaxis for infectious endocarditis in our setting: Are the guidelines followed? / Conducta de los profesionales sanitarios ante las recomendaciones de profilaxis de endocarditis infecciosa en nuestro medio: ¿se siguen las guías?

OBJECTIVES: The prophylaxis regimens for infectious endocarditis recommended by the clinical practice guidelines have recently changed. We do not know whether the current regimens are correctly followed in our setting. Our objective was to describe the approaches of various health professionals concerning these guidelines. MATERIAL AND METHODS: We conducted a survey in Cordoba, using a 16-item online questionnaire on this topic. We randomly selected a sample of 180 practitioners (20 cardiologists, 80 dentists and 80 primary care physicians), of whom 173 responded. RESULTS: Half of the participants were men; 52% had more than 20 years of professional experience. Some 88.3% of the participants considered that prophylaxis of endocarditis is effective (77.8% of the cardiologists, 93.7% of the dentist; p=.086). In general, prophylaxis is performed in conditions of clearly established risk (>90% of those surveyed). However, prophylaxis is also performed in a high proportion of cases with no risk of endocarditis, varying between 30 and 60% according to the procedure (mostly the dentists, between 36 and 67%, followed by the primary care physicians, between 28 and 59%). The antibiotic regimens employed varied significantly. The primary care physicians were furthest from the recommended regimen (only 25.8% used the recommended regimen vs. 54.4% of dentists and 72.2% of cardiologists; p=.002). CONCLUSIONS: Compliance with the recommendations on prophylaxis for endocarditis should be improved in our setting. We observed a tendency, especially among noncardiologists, to "overindicate" the prophylaxis.

Factors related to variability in long-term oxygen therapy prevalence.

OBJECTIVE: To analyse the variability of long term oxygen therapy (LTOT) prevalence according to several organisational and population factors. METHODS: Prospective multicentre survey in 29 public hospitals (population 6,796,964) recording data on the organisational structure of the participating centres and factors related to LTOT prevalence. Official figures were also obtained from local health authorities on the prevalence and cost of LTOT. RESULTS: The overall prevalence of LTOT was 184 per 100000 population (range 71-473). There was a specific unit or staff member for LTOT supervision in 17 (58.6%) centres, giving a lower prevalence (169 vs. 237/ 100000; P = 0.03). The altitude of the participating centres (median 92 m, mean 275 m; range 4-848 m) was found to influence LTOT prevalence (r = 0.73; P = 0.005). In the linear regression analysis, the coefficient of determination for altitude was 0.504. Other factors, such as percentage of population aged over 65 years, the attitude of prescribers towards patients with low adherence, current smokers or those with a PaO2 = 61 mmHg, were not related to LTOT prevalence. CONCLUSIONS: Altitude and the existence of a specific unit or staff member for LTOT supervision significantly influence LTOT prevalence.

Predictores de éxito del tratamiento con cánula nasal de alto flujo en el fallo respiratorio agudo hipoxémico / Predictors of success of high-flow nasal cannula in the treatment of acute hypoxemic respiratory failure

Introducción: La terapia con cánula nasal de alto flujo (CNAF) se ha introducido recientemente en el tratamiento del fallo respiratorio agudo (FRA), siendo una técnica segura, confortable y eficaz que logra revertir la hipoxemia en estos pacientes. Es necesario disponer de herramientas que nos permitan detectar precozmente el fallo de este tipo de tratamiento para evitar el incremento de la mortalidad que puede conllevar. El objetivo primario de este estudio ha sido analizar el impacto que la frecuencia respiratoria (FR), la saturación periférica de oxígeno (SpO2), la fracción inspirada de oxígeno (FiO2) y el índice ROX (IROX=[SpO2/FiO2]/FR) tienen sobre el éxito de la CNAF en los pacientes con FRA hipoxémico. Los objetivos secundarios han sido analizar la estancia y la mortalidad en la UCI y la necesidad de ventilación mecánica (VM). Material y métodos Se trata de un estudio retrospectivo efectuado en una UCI polivalente del Hospital Comarcal de Montilla (Córdoba). Se incluyeron los pacientes tratados con CNAF por FRA hipoxémico desde enero de 2016 hasta enero de 2018.ResultadosDesde enero de 2016 hasta enero de 2018 se trataron 27 pacientes con FRA, de los cuales 19 (70,37%) presentaban FRA hipoxémico. De estos, 15 (78,95%) respondieron bien al tratamiento y 4 (21,05%) fracasaron. A las 2h de tratamiento la FR demostró ser el mejor predictor (área bajo la curva ROC [AUROC] 0,858; IC95%: 0,63-1,05; p=0,035). La FiO2 y el IROX fueron buenos predictores a las 8h de tratamiento (FiO2: AUROC 0,95; IC95%: 0,85-1,04; p=0,007, e IROX: AUROC 0,967; IC95%: 0,886-1,047; p=0,005). El mejor punto de corte de la FR a la segunda hora fue de 29 respiraciones/min (sensibilidad 75%, especificidad 87%). El mejor punto de corte de la FiO2 a las 8h de tratamiento fue de 0,59 (75% sensibilidad, 93% especificidad). El mejor punto de corte para IROX a las 8h de tratamiento fue de 5,98 (sensibilidad 100%, especificidad 75%). ... (AU)

Background: High-flow nasal cannula (HFNC) therapy is used in the treatment of acute respiratory failure (ARF) and is both safe and effective in reversing hypoxemia. In order to minimize mortality and clinical complications associated to this practice, a series of tools must be developed to allow early detection of failure. The present study was carried out to: (i)examine the impact of respiratory rate (RR), peripheral oxygen saturation (SpO2), ROX index (ROXI=[SpO2/FiO2]/RR) and oxygen inspired fraction (FiO2) on the success of HFNC in patients with hypoxemic ARF; and (ii)analyze the length of stay and mortality in the ICU, and the need for mechanical ventilation (MV).MethodsA retrospective study was carried out in the medical-surgical ICU of Hospital de Montilla (Córdoba, Spain). Patients diagnosed with hypoxemic ARF and treated with HFNC from January 2016 to January 2018 were included.ResultsOut of 27 patients diagnosed with ARF, 19 (70.37%) had hypoxemic ARF. Fifteen of them (78.95%) responded satisfactorily to HFNC, while four (21.05%) failed. After two hours of treatment, RR proved to be the best predictor of success (area under the ROC curve [AUROC] 0.858; 95%CI: 0.63-1.05; P=.035). For this parameter, the optimal cutoff point was 29rpm (sensitivity 75%, specificity 87%). After 8hours of treatment, FiO2 and ROXI were reliable predictors of success (FiO2: AUROC 0.95; 95%CI: 0.85-1.04; P=.007 and ROXI: AUROC 0.967; 95%CI: 0.886-1.047; P=.005). In the case of FiO2 the optimal cutoff point was 0.59 (sensitivity 75%, specificity 93%), while the best cutoff point for ROXI was 5.98 (sensitivity 100%, specificity 75%). Using a Cox regression model, we found RR<29rpm after two hours of treatment, and FiO2<0.59 and ROXI>5.98 after 8hours of treatment, to be associated with a lesser risk of MV (RR: HR 0.103; 95%CI: 0.11-0.99; P=.05; FiO2: HR 0.053; 95%CI: 0.005-0.52; P=.012; and ROXI: HR 0.077; 95%CI: 0.008-0.755; P=.028, respectively). ... (AU)

Respiratory disorders and quality of sleep in patients on the waiting list for lung transplantation.

BACKGROUND: The purpose of this study was to assess the quality of sleep and extent of respiratory disorders in patients awaiting lung transplantation as compared with a control group. METHODS: From September 2003 to November 2003, 17 clinically stable patients on the waiting list for lung transplantation and 14 healthy controls (with similar age, gender, and body mass index) were studied. Diagnostic polysomnography (PSG) was carried out for all subjects. RESULTS: Seventeen patients were included, 15 men and 2 women, aged 51 +/- 14 years. The indication for lung transplantation was emphysema in 7 cases, pulmonary fibrosis in 6, and "other" in 4. Patients awaiting lung transplantation had the following respiratory values: mean FEV1, 1105 mL (34% of predicted); PaO2, 54 mm Hg; and PaCO2, 44 mm Hg. Significant differences were found among the waiting-list patients in terms of predominance of light sleep, wakeful periods, and phase changes per sleep-hour, as compared with the control group. The recording of the respiratory events showed an apnea-hypopnea index of 6.13, sleeping time with SaO2 <90% of 1.80%, and a mean number of significant desaturations (<4%) of 6.38. There were no statistically significant differences with respect to the control group. CONCLUSIONS: Poor quality of sleep was observed in patients awaiting lung transplantation as compared with a healthy control group. There was no evidence of more respiratory events or significant desaturations in these patients, probably due to the provision of supplementary oxygen therapy during the PSG.

Allogeneic peripheral blood stem cell transplantation using reduced intensity versus myeloablative conditioning regimens for the treatment of leukemia.

Reduced intensity conditioning (RIC) have allowed the application of transplantation to older patients and to patients with underlying medical problems. Between October, 1999, and June, 2003, 61 patients with acute leukemia or chronic myeloid leukemia received allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT) from HLA-identical siblings. Thirty-four were conditioned with myeloablative protocols and twenty-seven with RIC regimens. The patients in the myeloablative group were younger (29 vs. 37 years; p < 0.0003), most of them were transplanted in complete remission (74% vs. 59%; p < 0.03), had a shorter interval between diagnosis and HSCT (12 vs. 21 months; p < 0.02) and a greater proportion belonged to standard-risk prognosis (68% vs. 48%; p < 0.1). The median times to neutrophil, platelet and red blood cell engraftment for the myeloablative and RIC groups were 14 versus 11 days (p < 0.009), 17 versus 9 days (p < 0.0001), and 19 versus 12 days (p < 0.007), respectively. Transfusion requirements were lower in the RIC group. Severe mucositis was present in 32% and 7%, respectively (p < 0.01). The proportion of patients having acute graft versus-disease (GVHD), chronic GVHD, and infections was the same, as well as early and late mortality, disease-free survival, and overall survival. Analyzing all the patients together, three factors significantly influenced overall survival: standard risk patients, complete remission at transplant, and the absence of severe acute GVHD. In conclusion, our data suggest that even in high-risk patients, RIC transplantation seems to be as useful as ablative HSCT.

[Hematopoietic cell transplantation. Experience at the Western National Medical Center]. / Trasplante de células hematopoyéticas. Experiencia del Centro Médico Nacional de Occidente.

UNLABELLED: Bone marrow transplantation has recently reached an special place as a therapeutic tool, which was not available ten years ago. AIM AND SETTING: Descriptive information about the first fifteen cases transplanted at Centro Médico Nacional de Occidente, on a third level attention in Guadalajara, Jalisco, Mexico. MATERIAL AND METHODS: Fifteen patients were transplanted, were carried out autologous transplantation in ten patients and five have received allogeneic transplant; one allogeneic transplant was performed with bone marrow aspiration donor, all next donation were taken off from peripheral blood stem cell through apheresis procedures. From autologous transplant 3 with chronic myelogenous leukemia (CML), 3 with Hodgkin's disease, 2 with solid tumor, 1 with high risk acute myelogenous leukemia and 1 large and small cell lymphoma III-B stage. Received allogeneic transplant 4 patients with CML in chronic phase and one with acute lymphoblastic leukemia Ph+. RESULTS: All patients grafted, the median time to achieve > 0.5 x 10(9)/L granulocytes was 14 days (range: 11-18) from autologous and 16 (range: 14-18) days from allogeneic transplant, whereas the median time to achieve > 20 x 10(9)/L platelets was 18 days (range: 15-35) from autologous and 22 days from allogeneic, three patients died into 100 days postprocedure, two allogeneic, from graft versus host disease III-IV degree, and one autologous from interstitial pneumonia, surviving patients have showed +30 days to +1000 days survival. CONCLUSION: With these data we show that this procedure is inexpensive, is factible and possible if it does coexist with multidisciplinary and on time support, interest, dedication on care, and enough information and desire to do it, including official decisions to perform and sponsor its continuity to the people who participate in it.

[Use of an amorphous dressing in the skin care of patients after radiotherapy]. / Utilización de un apósito amorfo en el cuidado de la piel de pacientes en curso de tratamiento radioterápico.

INTRODUCTION: Skin wounds caused by acute radiogen toxicity are an important side effect caused by radiotherapy treatment, therefore the prevention and immediate care is a challenge for the nursing staff. The actual traditional treatment is based on Liniment Oleocalcareo creams with Zinc Oxide as a principal agreement, but we have discovered a new alternative that at a first instance respond more effectively to the patients needs, and are classified with the terminology "amourphous dressing". MATERIAL AND METHODS: Retrospective study of the application of the amorphous dressing on 41 patients during the period between February and June 1998 in the Radiotherapy Unit of the "Hospital Universitario Sant Joan de Reus" (Tarragona). RESULTS: The application of the amorphous dressing has allowed us to evidence a slowness and decrease in the intensity of the skin damage caused by the radiation treatment. There has been a 63.86% decrease of the nursing treatment of the skin wounds as a consequence of the radiotherapy. The use of the amourphous dressing with Zinc Oxide favours the ephithelization of the moist wounds. No adverse reaction of the dressing has been observed during the time of the study, and no infections process has been detected, in none of the case was the radiotherapy treatment interrupted due to radiodermatitis, and in none of the cases an alternative dressing was needed. In some cases the amourphous dressing in combination with a tulle and a polyamide grille the healing time of the radiodermitis wound was significantly decreased. It has also been verified that the application as well as the removal of the dressing does not involve any difficulty neither for the patients nor for the nursing staff. There also has been a better level of acceptance of the new amourphous dressing as well from both patients and staff, seeing that the therapeutic results is significantly superior than that of the previously used methods. CONCLUSIONS: Having carried out the study in our Radiotherapy Unit we can assure that the new amourphous dressing, along with a strict control of the patient's evolution, increases the comfort and the quality of life of the patients. The multidisciplinary acceptance of the new treatment in a protocolized manner implies an increase in the patient quality care as well as contributing to a more efficient allocation of resources.

Conducta de los profesionales sanitarios ante las recomendaciones de profilaxis de endocarditis infecciosa en nuestro medio: ¿se siguen las guías? / Behaviour of health professionals concerning the recommendations for prophylaxis for infectious endocarditis in our setting: Are the guidelines followed?

Objetivos. Las pautas de profilaxis de endocarditis infecciosa recomendadas por las guías de práctica clínica han cambiado recientemente. Se desconoce en nuestro medio si se siguen correctamente las pautas actuales. Nuestro objetivo es describir las actitudes de diferentes profesionales sanitarios ante ellas. Material y métodos. Hemos realizado una encuesta en Córdoba, mediante un cuestionario online con 16 ítems sobre este tema. Se seleccionó aleatoriamente una muestra de 180 profesionales (20 cardiólogos, 80 dentistas, 80 médicos de atención primaria), de la cual contestaron 173. Resultados. La mitad eran varones, teniendo más de 20 años de ejercicio profesional el 52%. El 88,3% consideró que la profilaxis de endocarditis es efectiva (cardiólogos, 77,8%, dentistas, 93,7%, p=0,086). En general, se realiza profilaxis en las situaciones de riesgo claramente establecidas (>90% de los encuestados), pero también en una alta proporción de casos sin riesgo de endocarditis, que oscila entre el 30 y el 60% según los procedimientos (más los dentistas, entre el 36 y 67%, seguidos de los médicos de atención primaria, entre el 28 y 59%). Las pautas antibióticas usadas son muy variadas, siendo los médicos de primaria los que se alejan más de lo recomendado (solo un 25,8% usaban la pauta recomendada, frente a un 54,4% de dentistas y un 72,2% de cardiólogos, p=0,002). Conclusiones. El seguimiento de las recomendaciones sobre profilaxis de endocarditis debe mejorarse en nuestro medio, observándose una tendencia, sobre todo en no cardiólogos, a una «sobreindicación» de la misma (AU)

Objectives. The prophylaxis regimens for infectious endocarditis recommended by the clinical practice guidelines have recently changed. We do not know whether the current regimens are correctly followed in our setting. Our objective was to describe the approaches of various health professionals concerning these guidelines. Material and methods. We conducted a survey in Cordoba, using a 16-item online questionnaire on this topic. We randomly selected a sample of 180 practitioners (20 cardiologists, 80 dentists and 80 primary care physicians), of whom 173 responded. Results. Half of the participants were men; 52% had more than 20 years of professional experience. Some 88.3% of the participants considered that prophylaxis of endocarditis is effective (77.8% of the cardiologists, 93.7% of the dentist; p=.086). In general, prophylaxis is performed in conditions of clearly established risk (>90% of those surveyed). However, prophylaxis is also performed in a high proportion of cases with no risk of endocarditis, varying between 30 and 60% according to the procedure (mostly the dentists, between 36 and 67%, followed by the primary care physicians, between 28 and 59%). The antibiotic regimens employed varied significantly. The primary care physicians were furthest from the recommended regimen (only 25.8% used the recommended regimen vs. 54.4% of dentists and 72.2% of cardiologists; p=.002). Conclusions. Compliance with the recommendations on prophylaxis for endocarditis should be improved in our setting. We observed a tendency, especially among noncardiologists, to 'overindicate' the prophylaxis (AU)

Resonance state in 7H.

The existence of the 7H nuclear system was investigated via a one-proton transfer reaction with a 8He beam at 15.4A MeV and a 12C gas target. The experimental setup was based on the active-target MAYA which allowed a complete reconstruction of the reaction kinematics. The existence of the 7H was confirmed with the identification of seven events where the system was formed with a resonance energy of 0.57(-0.21)(+0.42) MeV above the 3H+4n threshold and a resonance width of 0.09(-0.06)(+0.94) MeV. This study represents an unambiguous proof of the existence of the most neutron-proton unbalanced system presently found.

Transient effects in fission from new experimental signatures.

A new experimental approach is introduced to investigate the relaxation of the nuclear deformation degrees of freedom. Highly excited fissioning systems with compact shapes and low angular momenta are produced in peripheral relativistic heavy-ion collisions. Both fission fragments are identified in atomic number. Fission cross sections and fission-fragment element distributions are determined as a function of the fissioning element. From the comparison of these new observables with a nuclear-reaction code a value for the transient time is deduced.