Depairing currents in the superconductor/ferromagnet proximity system Nb/Fe

We have investigated the behaviour of the depairing current J_{dp} in ferromagnet/superconductor/ferromagnet (F/S/F) trilayers as function of the thickness d_s of the superconducting layers. Theoretically, J_{dp} depends on the superconducting order parameter or the pair density function, which is not homogeneous across the film due to the proximity effect. We use a proximity effect model with two parameters (proximity strength and interface transparency), which can also describe the dependence of the superconducting transition temperature T_c on d_s. We compare the computations with the experimentally determined zero-field critical current J_{c0} of small strips (typically 5~ \mu m wide) of Fe/Nb/Fe trilayers with varying thickness d_{Nb} of the Nb layer. Near T_c the temperature dependence J_{c0}(T) is in good agreement with the expected behaviour, which allows extrapolation to T = 0. Both the absolute values of J_{c0}(0) and the dependence on d_{Nb} agree with the expectations for the depairing current. We conclude that J_{dp} is correctly determined, notwithstanding the fact that the strip width is larger than both the superconducting penetration depth and the superconducting coherence length, and that J_{dp}(d_s) is correctly described by the model.Comment: 10 pages, 5 figures, submitted to PR

Assessment of online water-soluble brown carbon measuring systems for aircraft sampling

Brown carbon (BrC) consists of particulate organic species that preferentially absorb light at visible and ultraviolet wavelengths. Ambient studies show that as a component of aerosol particles, BrC affects photochemical reaction rates and regional to global climate. Some organic chromophores are especially toxic, linking BrC to adverse health effects. The lack of direct measurements of BrC has limited our understanding of its prevalence, sources, evolution, and impacts. We describe the first direct, online measurements of water-soluble BrC on research aircraft by three separate instruments. Each instrument measured light absorption over a broad wavelength range using a liquid waveguide capillary cell (LWCC) and grating spectrometer, with particles collected into water by a particle-into-liquid sampler (CSU PILS-LWCC and NOAA PILS-LWCC) or a mist chamber (MC-LWCC). The instruments were deployed on the NSF C-130 aircraft during WE-CAN 2018 as well as the NASA DC-8 and the NOAA Twin Otter aircraft during FIREX-AQ 2019, where they sampled fresh and moderately aged wildfire plumes. Here, we describe the instruments, calibrations, data analysis and corrections for baseline drift and hysteresis. Detection limits (3σ) at 365 nm were 1.53 Mm−1 (MC-LWCC; 2.5 min sampling time), 0.89 Mm−1 (CSU PILS-LWCC; 30 s sampling time), and 0.03 Mm−1 (NOAA PILS-LWCC; 30 s sampling time). Measurement uncertainties were 28 % (MC-LWCC), 12 % (CSU PILS-LWCC), and 11 % (NOAA PILS-LWCC). The MC-LWCC system agreed well with offline measurements from filter samples, with a slope of 0.91 and R2=0.89. Overall, these instruments provide soluble BrC measurements with specificity and geographical coverage that is unavailable by other methods, but their sensitivity and time resolution can be challenging for aircraft studies where large and rapid changes in BrC concentrations may be encountered

Ataxin-2 intermediate-length polyglutamine expansions in European ALS patients

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disease primarily affecting motor neurons. We recently identified intermediate-length polyglutamine (polyQ) expansions (27-33 Qs) in ataxin 2 as a genetic risk factor for sporadic ALS in North American ALS patients. To extend these findings, we assessed the ataxin 2 polyQ repeat length in 1294 European ALS patients and 679 matched healthy controls. We observed a significant association between polyQ expansions and ALS (>30 Qs; P= 6.2 × 10−3). Thus, intermediate-length ataxin 2 polyQ repeat expansions are associated with increased risk for ALS also in the European cohort. The specific polyQ length cutoff, however, appears to vary between different populations, with longer repeat lengths showing a clear association. Our findings support the hypothesis that ataxin 2 plays an important role in predisposing to ALS and that polyQ expansions in ataxin 2 are a significant risk factor for the diseas

Democratic Legitimacy of Politically Unaccountable Administrative Authorities in Comparative Constitutional Law

Uz temeljna ustavna načela vladavine prava i podjele vlasti, načelo kolektivne i pojedinačne ministarske odgovornosti jamac je demokratskog legitimiteta uprave, koji leži u neprekinutom lancu delegacije i odgovornosti od birača prema parlamentu, od parlamenta do ministra te od ministra kroz sve razine uprave do razine najbliže građanima. U ovom radu razmatra se ustavnopravna osnovanost demokratskog legitimiteta neovisnih regulatornih tijela, s posebnim osvrtom na načelo ministarske odgovornosti. Poredbeno se obrađuju primjeri iz europskih država, gdje neovisnost regulatornih tijela ne zadire u temeljna ustavna načela. Zaključno se nastoji utvrditi u kojoj mjeri formalno utvrđena politička neovisnost jamči takvu neovisnost u materijalnom smislu te se razmatraju neke od najutjecajnijih teorija koje o svrsi osnivanja neovisnih regulatornih tijela nudi politička znanost.In addition to the fundamental constitutional principles of the rule of law and separation of powers, the principle of collective and individual ministerial responsibility is the guarantee of the democratic legitimacy of administration that lies in the unbroken chains of delegation and accountability from voters to Parliament, from Parliament to the minister, and from the minister through all levels of administration, to the level closest to citizens. This paper examines the theoretical constructions of the democratic legitimacy of independent regulatory authorities from the constitutionalist point of view, with particular reference to the principle of ministerial responsibility. It further discusses comparative examples from European countries where the independence of the regulatory authorities does not violate fundamental constitutional principles. In conclusion, this paper seeks to determine the extent to which formally established political independence guarantees such independence in the material sense, bearing in mind some of the most influential theories on the purpose of the establishment of independent regulatory authoritie

Introducing comics as an alternative scientific narrative in chemistry teaching

In this work we present an experience report involving the execution of a pedagogical workshop about comics with Chemistry teaching undergraduate students. The workshop had as main goal to promote a discussion on the potential of narratives as an alternative approach to teach Chemistry, focusing on the development of teachers' authorship of pedagogical material and at the same time on the integration of information and communication technologies (ICT) in the classroom. The report is divided in two segments: (i) the description of the workshop execution; (ii) a synthesis of the reflections collected from the participants by means of a questionnaire applied in the end of the workshop. The main results praise comics' playful character and their potential to stimulate creativity in students, as well as indicate the relevance of educational material authorship in the pedagogical practices of professors in training. Overall, the discussions performed point to the still incipient presence of ICT in the pedagogical training of Chemistry teaching degrees, which highlights the pressing need for incorporating these technologies on formative practices. Moreover, reflections on the pedagogical value of using comics as a narrative approach aiming at the development of scientific and media literacy were raised by the present wor

Silence Is Not Golden: Invisible Latinas Living with HIV in the Midwest

This qualitative study was conducted to better understand the health needs and concerns of immigrant HIV-infected Latinas residing in the Midwest United States. Individual interviews (n = 18) were conducted in Spanish with Latinas in Kansas, Oklahoma and Missouri. Women were at different stages of acceptance about their HIV diagnosis and four common themes emerged from the data: pregnancy as a death sentence, HIV is taboo, God as their only resource, and living in isolation. Silence was an over-arching theme present throughout all the narratives and many women had never shared their stories about HIV with anyone. Depressive symptoms and suicidal ideation were common. These findings have implications for strategies to address the HIV prevention and HIV-related healthcare needs of this population of women. Results from this study further suggest that efforts are needed to break the silence surrounding HIV and to reduce HIV-related stigma in smaller Midwestern Hispanic communities

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Multiplexed pancreatic genome engineering and cancer induction by transfection-based CRISPR/Cas9 delivery in mice

Mouse transgenesis has provided fundamental insights into pancreatic cancer, but is limited by the long duration of allele/model generation. Here we show transfection-based multiplexed delivery of CRISPR/Cas9 to the pancreas of adult mice, allowing simultaneous editing of multiple gene sets in individual cells. We use the method to induce pancreatic cancer and exploit CRISPR/Cas9 mutational signatures for phylogenetic tracking of metastatic disease. Our results demonstrate that CRISPR/Cas9-multiplexing enables key applications, such as combinatorial gene-network analysis, in vivo synthetic lethality screening and chromosome engineering. Negative-selection screening in the pancreas using multiplexed-CRISPR/Cas9 confirms the vulnerability of pancreatic cells to Brca2-inactivation in a Kras-mutant context. We also demonstrate modelling of chromosomal deletions and targeted somatic engineering of inter-chromosomal translocations, offering multifaceted opportunities to study complex structural variation, a hallmark of pancreatic cancer. The low-frequency mosaic pattern of transfection-based CRISPR/Cas9 delivery faithfully recapitulates the stochastic nature of human tumorigenesis, supporting wide applicability for biological/preclinical research

Multiplexed pancreatic genome engineering and cancer induction by transfection-based CRISPR/Cas9 delivery in mice.

Mouse transgenesis has provided fundamental insights into pancreatic cancer, but is limited by the long duration of allele/model generation. Here we show transfection-based multiplexed delivery of CRISPR/Cas9 to the pancreas of adult mice, allowing simultaneous editing of multiple gene sets in individual cells. We use the method to induce pancreatic cancer and exploit CRISPR/Cas9 mutational signatures for phylogenetic tracking of metastatic disease. Our results demonstrate that CRISPR/Cas9-multiplexing enables key applications, such as combinatorial gene-network analysis, in vivo synthetic lethality screening and chromosome engineering. Negative-selection screening in the pancreas using multiplexed-CRISPR/Cas9 confirms the vulnerability of pancreatic cells to Brca2-inactivation in a Kras-mutant context. We also demonstrate modelling of chromosomal deletions and targeted somatic engineering of inter-chromosomal translocations, offering multifaceted opportunities to study complex structural variation, a hallmark of pancreatic cancer. The low-frequency mosaic pattern of transfection-based CRISPR/Cas9 delivery faithfully recapitulates the stochastic nature of human tumorigenesis, supporting wide applicability for biological/preclinical research