Scaling of Island Growth in Pb Overlayers on Cu(001)

The growth and ordering of a Pb layer deposited on Cu(001) at 150 K has been studied using atom beam scattering. At low coverage, ordered Pb islands with a large square unit cell and nearly hexagonal internal structure are formed. This is a high order commensurate phase with 30 atoms in the unit cell. From the measurement of the island diffraction peak profiles we find a power law for the mean island - size versus coverage with an exponent $n=0.54 \pm 0.03$. A scaling behavior of growth is confirmed and a simple model describing island growth is presented. Due to the high degeneracy of the monolayer phase, different islands do not diffract coherently. Therefore, when islands merge they still diffract as separate islands and coalescence effects are thus negligible. From the result for $n$ we conclude that the island density is approximately a constant in the coverage range $0.1 < \Theta < 0.5$ where the ordered islands are observed. We thus conclude that most islands nucleate at $\Theta < 0.1$ and then grow in an approximately self similar fashion as $\Theta$ increases.Comment: 23 pages, 10 Figures (available upon request). SU-PHYS-93-443-375

Amygdala and Ventrolateral Prefrontal Cortex Activation to Masked Angry Faces in Children and Adolescents with Generalized Anxiety Disorder

1. Context. Vigilance to threat is a key feature of generalized anxiety disorder (GAD). The amygdala and ventrolateral prefrontal cortex comprise a neural circuit that is responsible for detection of threats. Disturbed interactions between these structures may underlie pediatric anxiety. To date, no study has selectively examined responses to briefly-presented threats (e.g. less than 50 msec) in GAD or in pediatric anxiety. 2. Objective. To investigate amygdala and ventrolateral prefrontal cortex activation during processing of briefly-presented threats in pediatric GAD. 3. Design. Case-control study. 4. Setting. Government clinical research institute. 5. Participants. Youth volunteers, 17 with GAD and 12 diagnosis-free. 6. Main Outcome Measures. We used functional magnetic resonance imaging to measure blood oxygenation level-dependent signal. During imaging, subjects performed an attention orienting task with rapidly presented (17 msec), masked emotional (angry or happy) and neutral faces. 7. Results. When viewing masked angry faces, GAD youth, relative to comparison subjects, showed greater right amygdala activation that positively correlates with anxiety disorder severity. Moreover, in a functional connectivity (psychophysiological interaction) analysis, right amygdala and right ventrolateral prefrontal cortex showed strong negative coupling specifically to masked angry faces. This negative coupling tended to be weaker in GAD youth than in comparisons. Conclusions. GAD youth have hyper-activation of the amygdala to briefly-presented, masked threats. The presence of threat-related negative connectivity between the right ventrolateral prefrontal cortex and amygdala suggests that the prefrontal cortex modulates amygdala response to threat. In pediatric GAD, hyper-amygdala response occurs in the absence of a compensatory increase in modulation by ventrolateral prefrontal cortex

Electromagnetic Probes

A review is presented of dilepton and real photon measurements in relativistic heavy ion collisions over a very broad energy range from the low energies of the BEVALAC up to the highest energies available at RHIC. The dileptons cover the invariant mass range \mll = 0 - 2.5 GeV/c$^2$, i.e. the continuum at low and intermediate masses and the light vector mesons, $\rho, \omega, \phi$. The review includes also measurements of the light vector mesons in elementary reactions.Comment: To be published in Landolt-Boernstein Volume 1-23A; 40 pages, 24 figures. Final version updated with small changes to the text, updated references and updated figure

A population-based linked cohort of cancer and primary care data: A new source to study the management of cancer in primary care

Objective: Insight into the management of cancer in the primary care setting is pivotal to improve early recognition and survival of cancer patients. Therefore, the Netherlands Cancer Registry (NCR) was linked to the General Practitioner (GP) Database of the PHARMO Database Network to make this research possible. Methods: The NCR collects tumour data on all newly diagnosed cancer patients, whereas the GP Database comprises data from electronic patient records registered by GPs. Databases were linked using a probabilistic record linkage technology. Results: Through record linkage of the NCR and the GP Database, we have established a large population-based cohort (NCR-PHARMO GP cohort) of 135,868 cancer patients. Data are available on demographics, tumour characteristics, primary health care use before and after cancer diagnosis including medication use, medical conditions, laboratory tests, and referrals. Data can be used for a number of different studies, for example, to study the diagnostic pathway in the primary care setting in order to identify possibilities for early recognition. Conclusion: The NCR-PHARMO GP cohort provides rich data on the primary care management of cancer facilitating large-scale observational cancer research in the primary care setting. The patient-level linkage allows for long-term follow-up of cancer patients, with ongoing annual updates

Higher-order Hahn's quantum variational calculus

We prove a necessary optimality condition of Euler-Lagrange type for quantum variational problems involving Hahn's derivatives of higher-order. (C) 2011 Elsevier Ltd. All rights reserved

Bluefin tuna (Thunnus thynnus) tagging survey in the Bay of Biscay in summer 2005

A brief summary of the conventional tagging survey carried out during the summer fishing season in 2005 in the Bay of Biscay is presented. A total of 1696 juveniles of bluefin tuna have been tagged, corresponding to group ages 1 and 2. Two different conventional tags have been used. Fifty-one recaptures have been recovered up to date.Le présent document fournit un résumé de la campagne de marquage conventionnel de thon rouge menée au cours de l’été 2005 dans le Golfe de Gascogne. Au total, 1.696 juvéniles de thon rouge ont été marqués, correspondant aux groupes d’âge 1 et 2. Deux types distincts de marques conventionnelles ont été utilisés. Cinquante-et-une marques ont été récupérées à ce jour.Se presenta un resumen de la campaña de marcado convencional de atún rojo llevada a cabo durante el verano del 2005 en el Golfo de Vizcaya. En total se han marcado 1696 ejemplares de 1 y 2 años de edad. Se han utilizado dos modelos distintos de marcas convencionales. Hasta la fecha se han recapturado cincuenta y un ejemplares

Burden of waiting for surveillance CT colonography in patients with screen-detected 6–9 mm polyps

Purpose: We assessed the burden of waiting for surveillance CT colonography (CTC) performed in patients having 6–9 mm colorectal polyps on primary screening CTC. Additionally, we compared the burden of primary and surveillance CTC. Materials and methods: In an invitational population-based CTC screening trial, 101 persons were diagnosed with <3 polyps 6–9 mm, for which surveillance CTC after 3 years was advised. Validated questionnaires regarding expected and perceived burden (5-point Likert scales) were completed before and after index and surveillance CTC, also including items on burden of waiting for surveillance CTC. McNemar’s test was used for comparison after dichotomization. Results: Seventy-eight (77 %) of 101 invitees underwent surveillance CTC, of which 66 (85 %) completed the expected and 62 (79 %) the perceived burden questionnaire. The majority of participants (73 %) reported the experience of waiting for surveillance CTC as ‘never’ or ‘only sometimes’ burdensome. There was almost no difference in expected and perceived burden between surveillance and index CTC. Waiting for the results after the procedure was significantly more burdensome for surveillance CTC than for index CTC (23 vs. 8 %; p = 0.012). Conclusion: Waiting for surveillance CTC after primary CTC screening caused little or no burden for surveillance participants. In general, the burden of surveillance and index CTC were comparable. Key points: • Waiting for surveillance CTC withi

Computer tomography colonography participation and yield in patients under surveillance for 6-9 mm polyps in a population-based screening trial

Purpose: Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. Material and methods: In an invitational CTC screening trial 82 of 982 participants harboured 6-9 mm polyps as the largest lesion(s) for which surveillance CTC was advised. Only participants with one or more lesion(s) ≥6 mm at surveillance CTC were offered colonoscopy (OC); 13 had undergone preliminary OC. The surveillance CTC yield was defined as the number of participants with advanced neoplasia in the 82 surveillance participants, and was added to the primary screening yield. Results: Sixty-five of 82 participants were eligible for surveillance CTC of which 56 (86.2 %) participated. Advanced neoplasia was diagnosed in 15/56 participants (26.8 %) and 9/13 (69.2 %) with preliminary OC. Total surveillance yield was 24/82 (29.3 %). No carcinomas were detected. Adding surveillance results to initial screening CTC yield significantly increased the advanced neoplasia yield per 100 CTC participants (6.1 to 8.6; p < 0.001) and per 100 invitees (2.1 to 2.9; p < 0.001). Conclusion: Surveillance CTC for 6-9 mm polyps has a substantial yield of advanced adenomas and significantly increased the CTC yield in population screening. Key Points: • The participation rate in surveillance CT colonography (CTC) is 86 %. • Advanced adenoma prevalence in a 6-9 mm CTC surveillance population is high. • Surveillance CTC significantly increases the yield of population screening by CTC. • Surveillance CTC for 6-9 mm polyps is a safe strategy. • Sur

Tracking bluefin tuna cohorts from east Atlantic Spanish fisheries since the 1980s

Relative abundance and mean size at age analyses were performed for the catches of three Atlantic Spanish fisheries, in search of an exceptionally abundant cohort in the recent history of the eastern Atlantic and Mediterranean bluefin tuna stock. Length distributions of baitboat fisheries, both in the Bay of Biscay and areas close to the Strait of Gibraltar as well as trap catches from the Spanish Atlantic coast were converted to age distributions using age length keys from calcified structures. Results do validate indirectly the ageing method. The 1994 cohort was clearly tracked for juveniles and young adults, 3 to 7 years old, in baitboat catches, and also for older specimens, 9 to 11 years old, in the trap fisheries. Based on these results, it is suggested that the juvenile and young adults fisheries in the western part of the Iberian Peninsula are interconnected between one another and with the Balearic Islands area of the western Mediterranean, as it is the nearest spawning ground described and because it is also supported by tagging and other studies.Afin de trouver une cohorte exceptionnellement abondante dans la récente histoire du stock de ton rouge de l’Atlantique Est et de la Méditerranée, on a procédé à une analyse de l’abondance relative et de la taille moyenne par âge des captures réalisées par trois pêcheries espagnoles de l’Atlantique. Les distributions par tailles de deux pêcheries de canneurs dans le Golfe de Gascogne et dans les eaux proches du Détroit de Gibraltar, ainsi que les prises des madragues de la côte atlantique espagnole, ont été converties en âges à l’aide des clefs taille-âge obtenues à partir de la lecture de structures calcifiées. Les résultats valident indirectement la méthode de détermination de l’âge. La cohorte de 1994 affiche une forte indication présente chez les juvéniles et les jeunes adultes, de 3 à 7 ans, capturés dans les pêcheries de canneurs ainsi que chez les spécimens d’âge plus avancé, de 9 à 11 ans, pêchés à la madrague. Ces résultats suggèrent que les pêcheries de juvéniles et de jeunes adultes de la partie occidentale de la péninsule ibérique sont interconnectées entre elles ainsi qu’avec la zone des îles Baléares, en Méditerranée occidentale, étant donné qu’il s’agit de la zone de frai la plus proche et qu’il existe des indices de cette relation d’après les études de marquage et d’autres études.Para encontrar una cohorte excepcionalmente abundante en la historia reciente del stock de atún rojo del Atlántico este y Mediterráneo, se realizó un análisis de la abundancia relativa y la talla media por edad de las capturas de tres pesquerías atlánticas españolas. Las distribuciones de tallas de dos pesquerías de cebo vivo, en el Golfo de Vizcaya y en aguas próximas al Estrecho de Gibraltar, así como las capturas de las almadrabas de la costa atlántica española, fueron convertidas a edades mediante el uso de claves talla edad, obtenidas a partir de la lectura de piezas esqueléticas. Los resultados validan indirectamente el método de determinación de la edad. La cohorte de 1994 presenta una fuerte señal que pudo ser encontrada en los juveniles y adultos jóvenes, 3 a 7 años, capturados en las pesquerías de cebo vivo y también en especimenes mayores, 9 a 11 años, pescados con las almadrabas. Con esto resultados se sugiere que las pesquerías de juveniles y adultos jóvenes de la parte occidental de la península Ibérica están interconectadas entre ellas y con el área de las Islas Baleares, en el Mediterráneo occidental, puesto que es la zona de puesta más próxima y porque también hay evidencias de esta relación mediante el marcado y otros estudios