The pseudomorphic to bulk fcc phase transition of thin Ni films on Pd(100)

We have measured the transformation of pseudomorphic Ni films on Pd(100) into their bulk fcc phase as a function of the film thickness. We made use of x-ray diffraction and x-ray induced photoemission to study the evolution of the Ni film and its interface with the substrate. The growth of a pseudomorphic film with tetragonally strained face centered symmetry (fct) has been observed by out-of-plane x-ray diffraction up to a maximum thickness of 10 Ni layers (two of them intermixed with the substrate), where a new fcc bulk-like phase is formed. After the formation of the bulk-like Ni domains, we observed the pseudomorphic fct domains to disappear preserving the number of layers and their spacing. The phase transition thus proceeds via lateral growth of the bulk-like phase within the pseudomorphic one, i.e. the bulk-like fcc domains penetrate down to the substrate when formed. This large depth of the walls separating the domains of different phases is also indicated by the strong increase of the intermixing at the substrate-film interface, which starts at the onset of the transition and continues at even larger thickness. The bulk-like fcc phase is also slightly strained; its relaxation towards the orthomorphic lattice structure proceeds slowly with the film thickness, being not yet completed at the maximum thickness presently studied of 30 Angstrom (i.e. about 17 layers).Comment: 8 pages, 7 figure

Quantum size effects in the low temperature layer-by-layer growth of Pb on Ge(001)

The electronic properties of thin metallic films deviate from the corresponding bulk ones when the film thickness is comparable with the wavelength of the electrons at the Fermi level due to quantum size effects (QSE). QSE are expected to affect the film morphology and structure leading to the low temperature (LT) ``electronic growth'' of metals on semiconductors. In particular, layer-by-layer growth of Pb(111) films has been reported for deposition on Ge(001) below 130 K. An extremely flat morphology is preserved throughout deposition from four up to a dozen of monolayers. These flat films are shown to be metastable and to reorganize into large clusters uncovering the first Pb layer, pseudomorphic to the substrate, already at room temperature. Indications of QSE induced structural variations of the growing films have been reported for Pb growth on Ge(001), where the apparent height of the Pb(111) monatomic step was shown to change in an oscillatory fashion by He atom scattering (HAS) during layer-by-layer growth. The extent of the structural QSE has been obtained by a comparison of the HAS data with X-ray diffraction (XRD) and reflectivity experiments. Whereas step height variations as large as 20 % have been measured by HAS reflectivity, the displacement of the atomic planes from their bulk position, as measured by XRD, has been found to mainly affect the topmost Pb layer, but with a lower extent, i.e. the QSE observed by HAS are mainly due to a perpendicular displacement of the topmost layer charge density. The effect of the variable surface relaxation on the surface vibration has been studied by inelastic HAS to measure the acoustic dispersion of the low energy phonons.Comment: 28 pages (laTex,elsart) and 13 figures (eps); updated reference

Study of the isotropic contribution to the analysis of photoelectron diffraction experiments at the ALOISA beamline

The angular distribution of the intensity in photoemission experiments is affected by electron diffraction patterns and by a smoothly varying ISO contribution originated by both intrumental details and physical properties of the samples. The origin of the various contributions to the ISO component has been identified since many years. Nonetheless in this work we present original developement of the ED analysis, which arises from the evolution of instrumental performance, in terms of analyzers positioning and angular resolution, as well as collimation and size of X-ray beams in third generation synchrotron sources. The analytical treatement of the instrumental factors is presented in detail for the end station of the ALOISA beamline (Trieste Synchrotron), where a wide variety of scattering geometries is available for ED experiments. We present here the basic formulae and their application to experimental data taken on the Fe/Cu3Au(001) system in order to highlight the role of the various parameters included in the distribution function. A specific model for the surface illumination has been developed as well as the overlayer thickness and surface roughness have been considered.Comment: RevTex, nine pages with five eps figures; to be published in J. Electron Spectrosc. Relat. Pheno

Acting without being in control: Exploring volition in Parkinson's disease with impulsive compulsive behaviours.

BACKGROUND: Several aspects of volitional control of action may be relevant in the pathophysiology of impulsive-compulsive behaviours (ICB) in Parkinson's disease (PD). We aimed to explore multiple aspects of action control, assessing reward-related behaviour, inhibition (externally and internally triggered) and sense of agency in PD patients, with and without ICB compared to healthy subjects. METHODS: Nineteen PD patients with ICB (PD-ICB), 19 PD without ICB (PD-no-ICB) and 19 healthy controls (HC) underwent a battery of tests including: Intentional Binding task which measures sense of agency; Stop Signal Reaction Time (SSRT) measuring capacity for reactive inhibition; the Marble task, assessing intentional inhibition; Balloon Analog Risk Task for reward sensitivity. RESULTS: One-way ANOVA showed significant main effect of group for action binding (p = 0.004, F = 6.27). Post hoc analysis revealed that PD-ICB had significantly stronger action binding than HC (p = 0.004), and PD-no-ICB (p = 0.04). There was no difference between PD-no-ICB and HC. SSRT did not differ between PD groups, whereas a significant difference between PD-no-ICB and HC was detected (p = 0.01). No other differences were found among groups in the other tasks. CONCLUSIONS: PD patients with ICB have abnormal performance on a psychophysical task assessing sense of agency, which might be related to a deficit in action representation at cognitive/experiential level. Yet, they have no deficit on tasks evaluating externally and internally triggered inhibitory control, or in reward-based decision-making. We conclude that impaired sense of agency may be a factor contributing to ICB in PD patients

The Planck Low Frequency Instrument

The Low Frequency Instrument (LFI) of the "Planck Surveyor" ESA mission will perform high-resolution imaging of the Cosmic Microwave Background anisotropies at four frequencies in the 30-100 GHz range. We review the LFI main scientific objectives, the current status of the instrument design and the on-going effort to develop software simulations of the LFI observations. In particular we discuss the design status of the PLANCK telescope, which is critical for reaching adequate effective angular resolution.Comment: 10 pages, Latex (use epsfig.sty); 4 Postscript figures; Astrophys. Lett & Comm, in press. Proc. of the Conference: "The Cosmic Microwave Background and the Planck Mission", Santander, Spain, 22-25 June 199

Autonomic dysfunction in progressive supranuclear palsy

Background: The degree of involvement of the autonomic nervous system in progressive supranuclear palsy (PSP) has been investigated in several studies, often providing conflicting results. There is a need for a better characterization of autonomic dysfunction in PSP, to enhance our understanding of this highly disabling neurodegenerative disease including patients’ needs and possibly be of value for clinicians in the differential diagnosis among Parkinsonian syndromes. Methods: We applied a systematic methodology to review existing literature on Pubmed regarding autonomic nervous system involvement in PSP. Results: PSP reported quite frequently symptoms suggestive of autonomic dysfunction in all domains. Cardiovascular autonomic testing showed in some cases a certain degree of impairment (never severe). There was some evidence suggesting bladder dysfunction particularly in the storage phase. Dysphagia and constipation were the most common gastrointestinal symptoms. Instrumental tests seemed to confirm sudomotor and pupillomotor disturbances. Conclusions: PSP patients frequently reported visceral symptoms, however objective testing showed that not always these reflected actual autonomic impairment. Further studies are needed to better delineate autonomic profile and its prognostic role in PSP

Planck Low Frequency Instrument: Beam Patterns

The Low Frequency Instrument on board the ESA Planck satellite is coupled to the Planck 1.5 meter off-axis dual reflector telescope by an array of 27 corrugated feed horns operating at 30, 44, 70, and 100 GHz. We briefly present here a detailed study of the optical interface devoted to optimize the angular resolution (10 arcmin at 100 GHz as a goal) and at the same time to minimize all the systematics coming from the sidelobes of the radiation pattern. Through optical simulations, we provide shapes, locations on the sky, angular resolutions, and polarization properties of each beam.Comment: On behalf of the Planck collaboration. 3 pages, 1 figure. Article published in the Proceedings of the 2K1BC Experimental Cosmology at millimetre wavelength

Influence of bicarbonate/carbonate removal on magnesium hydroxide slurry: A pilot study

Nowadays, the continuous increase in raw materials demand is leading research to seek alternative and unconventional sources, such as waste industrial brine or seawater. Indeed, seawater and seawater brines (e.g. produced by seawater reverse osmosis (RO) desalination plant) can be exploited in order to recover fresh water but also to produce many other valuable minerals such as magnesium. The importance of the magnesium recovery stands for its high risk of supply and significant economic importance for key sectors in the European economy. Thus, magnesium has been defined as one of thirty-four Critical Raw Materials (CRMs) by the European Commission. In the framework of the Horizion 2020 European Project Water Mining, a novel and unconventional selective reactive crystallizer designed by ResourSEAs was tested for the recovery of magnesium in form of hydroxide by means of direct mixing with an alkaline solution (i.e. sodium hydroxide solution). This crystallizer is called Multiple Feed Plug Flow Reactor (MF-PFR). The MF-PFR was installed within an integrated demonstration plant aiming at the production of magnesium hydroxide, chemicals (such as sodium hydroxide and hydrochloric acid), fresh water, sodium sulfate, and sodium chloride, combining together (i) nanofiltration, (ii) MF-PFR, (iii) Eutetic Freez Crystallizer (EFC), (iv) Electro-dialysis with bipolar membrane, and (v) Multiple Effect Distillation (MED). A wide experimental campaign has been carried out aiming at investigating how the settling rate and purity are influenced by operative conditions, such brine feed or recycle flow-rates, and by the nature of the feed brine itself (i.e. NF retentate or RO retentate). The results obtained show that decreasing feed brine flow-rate is consistent with an increase in the settling rate, while conversely decreasing recycle flow rate leads to a clear decrease. This behavior was observed for both feed brine solutions. Moreover, also the influence of the presence of carbonate and bicarbonates in the feed stream on product settling rate and purity was investigated by applying an acidification pretreatment step. After this step, a purity increase from 94% up to 98/99% along with an increase in sedimentation rate (up to two times) was obtained. These outcomes were observed for both feed brine solutions

Commentary: Anderson-Fabry Disease: A Rare Cause of Levodopa-Responsive Early Onset Parkinsonism

This case had young onset parkinsonism beginning at age 45 mainly affecting the right side with foot dystonia and limb pain as an early and prominent feature.1 There was a family history of renal disease in one sister, stroke like episodes and dementia in another sister, and ischemic cardiac disease in the father. Single-photon emission computed tomography of the dopamine transporter showed bilateral reduced uptake and there was a good levodopa response and later development non-motor fluctuations. Although a number of parkinsonian conditions particularly genetic forms of young onset parkinsonism are in the differential, the patient also showed signs of renal (microalbuminuria) and cardiac (left ventricular hypertrophy) dysfunction which further narrowed the differential to conditions such as mitochondrial disease and neuronal inclusion body disease (though brain MRI did not show characteristic white matter changes). Given the severity of pain and renal involvement, Anderson-Fabry was considered as the most likely diagnosis. This x-linked lysosomal storage disease is caused by absent or minimal enzymatic activity of α-galactosidase and usually affects males in whom its fully penetrant but has been described rarely also to affect women.2 It is important to recognize this condition given the availability of treatment with enzyme replacement therapy (agalsidase alfa). The list of genetic parkinsonian conditions is increasing.2 Involvement of non-neurologic organ systems in patient or family members may offer clues to diagnosis. Anderson-Fabry disease specifically must be kept in mind in anyone with young onset parkinsoni