251 research outputs found

    Extraction from cyclotrons

    Get PDF

    Magnetotransport properties of iron microwires fabricated by focused electron beam induced autocatalytic growth

    Full text link
    We have prepared iron microwires in a combination of focused electron beam induced deposition (FEBID) and autocatalytic growth from the iron pentacarbonyl, Fe(CO)5, precursor gas under UHV conditions. The electrical transport properties of the microwires were investigated and it was found that the temperature dependence of the longitudinal resistivity (rhoxx) shows a typical metallic behaviour with a room temperature value of about 88 micro{\Omega} cm. In order to investigate the magnetotransport properties we have measured the isothermal Hall-resistivities in the range between 4.2 K and 260 K. From these measurements positive values for the ordinary and the anomalous Hall coefficients were derived. The relation between anomalous Hall resistivity (rhoAN) and longitudinal resistivity is quadratic, rhoAN rho^2 xx, revealing an intrinsic origin of the anomalous Hall effect. Finally, at low temperature in the transversal geometry a negative magnetoresistance of about 0.2 % was measured

    Diversity at the Ballot Box: Electoral Politics and Maine\u27s Minority Communities, Post-WWII to the Present

    Get PDF
    As this year’s Sampson Center exhibition makes clear the powerful desire to find historical inevitability in the advance toward equal opportunity for all Americans has become far more nuanced by the sometimes discomforting reminders that advances at the ballot box are neither as clear-cut nor as unconditional as we once hoped. The ancient antipathies of racism, anti-Semitism, and homophobia are not so easily elided by political campaigns and elections. The pace of social consensus requires a degree of patience and continuing attention that tries the very fabric of American life while we attempt to comprehend the consequences of change wrought by our heightened understanding of the implications of diversity in American life. Table of Contents: Introduction (Selma Botman, USM President) Quiet Revolution: A Tally of Black Victories (Bob Greene, for the African American Collection) Is It Good for the Jews? Is it Good for Everyone? Maine Jewry between Civic Idealism and the Politics of Reality (Abraham J. Peck, Scholar-in-Residence for the Judaica Collection) From the Closet to the Ballot-Box: Electoral Politics and Maine’s LGBT Citizens, 1970s to the Present (Howard M. Solomon, Scholar-in-Residence for the Lesbian, Gay, Bisexual, and Transgender Collection)https://digitalcommons.usm.maine.edu/event_catalog/1003/thumbnail.jp

    Gender and Tahrir Square: contesting the state and imagining a new nation

    Get PDF
    This article argues that the concepts of ‘State’ and ‘Nation’ should be treated as separate from one another, hence, more than one image of the nation is possible at one given time. During the early days of the January 2011 Egyptian revolution, a contestation emerged between Mubarak’s state and the protesters in Tahrir Square over the image and notion of the Egyptian nation. Both the state and the protesters attempted to exclude one another from their respective discourse of the Egyptian nation. While reflecting back on a number of women’s voices who joined the early days of the Tahrir Square protests and using qualitative fieldwork interviews with Cairo-based feminist and political activists, this article points to the complexity of a newly forged image of Egyptian nationhood. In Tahrir Square, this image appeared to be largely framed within gendered criteria where notions of manhood and hyper visible gender equality were intrinsically linked to the broader objective of removing Mubarak and his regime. This raises the question of whether new gender paradigms of equality can continue to exist beyond Tahrir Square’s imagination of a ‘new’ nation

    Explaining Africa’s public consumption procyclicality : revisiting old evidence

    Get PDF
    This paper compiles a novel dataset of time-varying measures of government consumption cyclicality for a panel of 46 African economies between 1960 and 2014. Government consumption has, generally, been highly procyclical over time in this group of countries. However, sample averages hide serious heterogeneity across countries with the majority of them showing procyclical behavior despite some positive signs of graduation from the “procyclicality trap” in a few cases. By means of weighted least squares regressions, we find that more developed African economies tend to have a smaller degree of government consumption procyclicality. Countries with higher social fragmentation and those are more reliant on foreign aid inflows tend to have a more procyclical government consumption policy. Better governance promotes counter- cyclical fiscal policy whileincreased democracy dampens it. Finally, some fiscal rules are important in curbing the procyclical behavior of government consumption.info:eu-repo/semantics/publishedVersio

    When Limb Surgery Has Become the Only Life-Saving Therapy in FOP: A Case Report and Systematic Review of the Literature

    Get PDF
    Fibrodysplasia ossificans progressiva (FOP) is a rare disease in which heterotopic ossification (HO) is formed in muscles, tendons and ligaments. Traumatic events, including surgery, are discouraged as this is known to trigger a flare-up with risk of subsequent HO. Anesthetic management for patients with FOP is challenging. Cervical spine fusion, ankylosis of the temporomandibular joints, thoracic insufficiency syndrome, restrictive chest wall disease, and sensitivity to oral trauma complicate airway management and anesthesia and pose life-threatening risks. We report a patient with FOP suffering from life-threatening antibiotic resistant bacterial infected ulcers of the right lower leg and foot. The anesthetic, surgical and postoperative challenges and considerations are discussed. In addition, the literature on limb surgeries of FOP patients is systemically reviewed. The 44 year-old female patient was scheduled for a through-knee amputation. Airway and pulmonary evaluation elicited severe abnormalities, rendering standard general anesthesia a rather complication-prone approach in this patient. Thus, regional anesthesia, supplemented with intravenous analgosedation and N2O-inhalation were performed in this case. The surgery itself was securely planned to avoid any unnecessary tissue damage. Postoperatively the patient was closely monitored for FOP activity by ultrasound and [18F]PET/CT-scan. One year after surgery, a non-significant amount of HO had formed at the operated site. The systematic review revealed seventeen articles in which thirty-two limb surgeries in FOP patients were described. HO reoccurrence was described in 90% of the cases. Clinical improvement due to improved mobility of the operated joint was noted in 16% of the cases. It should be noted, though, that follow-up time was limited and no or inadequate imaging modalities were used to follow-up in the majority of these cases. To conclude, if medically urgent, limb surgery in FOP is possible even when general anesthesia is not preferred. The procedure should be well-planned, alternative techniques or procedures should be tested prior to surgery and special attention should be paid to the correct positioning of the patient. According to the literature recurrent HO should be expected after surgery of a limb, even though it was limited in the case described

    Molecule-by-Molecule Writing Using a Focused Electron Beam

    Get PDF
    The resolution of lithography techniques needs to be extended beyond their current limits to continue the trend of miniaturization and enable new applications. But what is the ultimate spatial resolution? It is known that single atoms can be imaged with a highly focused electron beam. Can single atoms also be written with an electron beam? We verify this with focused electron-beam-induced deposition (FEBID), a direct-write technique that has the current record for the smallest feature written by (electron) optical lithography. We show that the deposition of an organometallic precursor on graphene can be followed molecule-by-molecule with FEBID. The results show that mechanisms that are inherent to the process inhibit a further increase in control over the process. Hence, our results present the resolution limit of (electron) optical lithography techniques. The writing of isolated, subnanometer features with nanometer precision can be used, for instance, for the local modification of graphene and for catalysis.</p

    Shadow Places: Patterns of Spatial Concentration and Incorporation of Irregular Immigrants in the Netherlands

    Get PDF
    Summary: In Western countries, irregular immigrants constitute a sizeable segment of the population. By combining quantitative and qualitative research methods, this article describes and explains irregular immigrants’ patterns of spatial concentration and incorporation in the Netherlands. So far these spatial patterns have not been described and explained systematically, neither in the Netherlands nor elsewhere. The article shows that illegal residence is selectively embedded in the (urban) social structure in various ways. The authors argue that irregular immigrants are likely to be spatially concentrated and incorporated in similar ways in other Western countries; now and in the foreseeable future
    • 

    corecore