Photoelectron spectra in strong-field ionization by a high frequency field

We analyze atomic photoelectron momentum distributions induced by bichromatic and monochromatic laser fields within the strong field approximation (SFA), separable Coulomb-Volkov approximation (SCVA), and ab initio treatment. We focus on the high frequency regime -- the smallest frequency used is larger than the ionization potential of the atom. We observe a remarkable agreement between the ab initio and velocity gauge SFA results while the velocity gauge SCVA fails to agree. Reasons of such a failure are discussed.Comment: Completely rewritten paper. Ionization by a two-color field is adde

Diatom assemblages from herbarium macrophytes and old samples: potential for historical limnology and studies from Flanders (Belgium)

Herbarium material of aquatic macrophytes and old limnological samples provide the opportunity to obtain precisely dated samples of epiphytic, planktonic or sedimentary diatom assemblages from the more recent past. These allow an accurate assessment of former limnological conditions at specific sites, in particular types of surface waters or associated to certain macrophytes, and even in entire regions. Inferences made from diatom assemblage composition may range from species abundance and diversity estimates to a reliable reconstruction of important parameters (e.g. pH, nutrient concentrations, salinity) by the use of indicator values or calibration techniques. Such information can be used to determine appropriate goals for management and restoration (pre-deterioration conditions), to track temporal changes by comparison with more recent data and relate these to possible external influences (e.g. various forms of pollution), or to evaluate monitoring data in a broader time perspective. In many cases, the use of old samples may not allow to generate time series of similar length and resolution as the more commonly applied diatom analysis of sediment cores. This technique, however, does provide access to the history of waters that do not have a suitable sediment record (e.g. because of dredging or sediment disturbance), avoids the problems often encountered in dating core levels accurately, and - with comparable or less effort -can be applied to a score of waters from a certain area. Also, it may be used to corroborate conclusions derived from sediment core analyses. Furthermore, the shorter time averaging of environmental conditions by epiphyton or plankton compared to sediment assemblages can be used advantageously to study short-lived or abruptly occurring phenomena. Limitations are, of course, related to the availability of suitable samples, the fact that most samples post-date c. 1850, and the reliability or detail of the information on place and date of collection. Moreover, variability caused by substrate and small-scale spatial differences in ecological conditions may be difficult to account for. For these reasons, it is recommendable to examine multiple samples of different nature (epiphyton of different plant species, sediment from between the roots, ...) from a given site. So far, old samples and herbarium material of aquatic plants have been used for a number of diatom investigations on lentic waters in Flanders. These include a number of case studies on specific water bodies, e.g. the Blankaart reservoir (Woumen), pools in the "Fonteintjes" (Zeebrugge), a survey of pools in the region of Kalmthout prior to 1945, and a 'typological' study of standing waters throughout the entire Flemish region. In order to facilitate the selection of suitable material for such studies, an inventory was made of some of the most important herbarium and sample collections held by Belgian universities and research institutes (including the herbaria BR, GENT, LV, BRVU, ANTW and that of UCL, and the collections of Van Oye at RUG and RUCA, and of Adam & Goossens at KBIN)

18F-fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging in patients with liver metastases from uveal melanoma: results from a pilot study.

PURPOSE: F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and MRI are used for detecting liver metastases from uveal melanoma. The introduction of new treatment options in clinical trials might benefit from early response assessment. Here, we determine the value of FDG-PET/CT with respect to MRI at diagnosis and its potential for monitoring therapy. MATERIAL AND METHODS: Ten patients with biopsy-proven liver metastases of uveal melanoma enrolled in a randomized phase III trial (NCT00110123) underwent both FDG-PET coupled with unenhanced CT and gadolinium-diethylene triamine pentaacetic acid-enhanced liver MRI within 4 weeks. FDG-PET and MRI were evaluated blindly and then compared using the ratio of lesion to normal liver parenchyma PET-derived standardized uptake value (SUV). The influence of lesion size and response to chemotherapy were studied. RESULTS: Overall, 108 liver lesions were seen: 34 (31%) on both modalities (1-18 lesions/patient), four (4%) by PET/CT only, and 70 (65%) by MRI only. SUV correlated with MRI lesion size (r=0.81, P<0.0001). PET/CT detected 26 of 33 (79%) MRI lesions of more than or equal to 1.2 cm, whereas it detected only eight of 71 (11%) lesions of less than 1.2 cm (P<0.0001). MRI lesions without PET correspondence were small (0.6±0.2 vs. 2.1±1.1 cm, P<0.0001). During follow-up (six patients, 30 lesions), the ratio lesion-to-normal-liver SUV diminished in size-stable lesions (1.90±0.64-1.46±0.50, P<0.0001), whereas it increased in enlarging lesions (1.56±0.40-1.99±0.56, P=0.032). CONCLUSION: MRI outweighs PET/CT for detecting small liver metastases. However, PET/CT detected at least one liver metastasis per patient and changes in FDG uptake not related to size change, suggesting a role in assessing early therapy response

The opposite of Dante's hell? The transfer of ideas for social housing at international congresses in the 1850s–1860s

With the advent of industrialization, the question of developing adequate housing for the emergent working classes became more pressing than before. Moreover, the problem of unhygienic houses in industrial cities did not stop at the borders of a particular nation-state; sometimes literally as pandemic diseases spread out 'transnationally'. It is not a coincidence that in the nineteenth century the number of international congresses on hygiene and social topics expanded substantially. However, the historiography about social policy in general and social housing in particular, has often focused on individual cases because of the different pace of industrial and urban development and is thus dominated by national perspectives. In this paper, I elaborate on transnational exchange processes and local adaptations and transformations. I focus on the transfer of the housing model of SOMCO in Mulhouse, (a French house building association) during social international congresses. I examine whether cross-national networking enabled and facilitated the implementation of ideas on the local scale. I will elaborate on the transmission and the local adaptation of the Mulhouse-model in Belgium. Convergences, divergences, and different factors that influenced the local transformations (personal choice, political situation, socioeconomic circumstances) will be taken into accoun

TARP as immunotherapeutic target in AML expressed in the LSC compartment

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