Ice Model Calibration using Semi-continuous Spatial Data

Rapid changes in Earth’s cryosphere caused by human activity can lead to significant environmental impacts. Computer models provide a useful tool for understanding the behavior and projecting the future of Arctic and Antarctic ice sheets. However, these models are typically subject to large parametric uncertainties due to poorly constrained model input parameters that govern the behavior of simulated ice sheets. Computer model calibration provides a formal statistical framework to infer parameters using observational data, and to quantify the uncertainty in projections due to the uncertainty in these parameters. Calibration of ice sheet models is often challenging because the relevant model output and observational data take the form of semi-continuous spatial data, with a point mass at zero and a right-skewed continuous distribution for positive values. Current calibration approaches cannot handle such data. Here we introduce a hierarchical latent variable model that handles binary spatial patterns and positive continuous spatial patterns as separate components. To overcome challenges due to high-dimensionality we use likelihood-based generalized principal component analysis to impose low-dimensional structures on the latent variables for spatial dependence. We apply our methodology to calibrate a physical model for the Antarctic ice sheet and demonstrate that we can overcome the aforementioned modeling and computational challenges. As a result of our calibration, we obtain improved future ice-volume change projections

Creative entrepreneurship and urban space

Academic scholarship has scrutinised the triangle connecting creativity, locality and economic activity in three ways. First, the clustering of firms has been found to promote creativity in an urban environment (cf. clustering theories). Second, and indicating an inverse course of action, creative individuals have been found to foster the economic growth of cities by attracting employers to places where the former want to reside (cf. creative class theory). Third, the specific attributes of a location, in particular urban environments, have been shown to have a positive impact on individual creativity. Our study adds to this fascinating liaison by exploring: the economic and non-economic features that lead to designers establishing their businesses in Athens’ city centre; and the perceived direct and indirect benefits of these locational factors in relation to the creative labour of these entrepreneurs. In this way, we merge micro and macro perspectives on the relationship between creative entrepreneurship and place, but in a potentially experimental setting, given that the urban fabric in Athens had to be reconstructed after it experienced economic and social turbulence following the 2008/2009 economic crisis and the austerity measures that were the resul

STATUS OF UVSOR-III

Abstract UVSOR-III is the 750 MeV synchrotron light source. In 2012, three new components were installed in the storage ring. First one is combined function bending magnets to reduce the emittance from 27.4 nm-rad to 16.9 nm-rad. These magnets can produce dipole, quadrupole and sextupole fields. Second one is an in-vacuum undulator. It was installed at 1.4 m straight section, which is the last free space reserved for insertion devices. As a result, the storage ring is now equipped with six undulators. Last one is a newly designed pulse sextupole magnet. This is beneficial to the user experiments in the top-up operation mode. The commissioning was started in June 2012 and the users operation was started in August 2012. Since then, we started to call the ring UVSOR-III. The in-vacuum undulator was successfully commissioned. The test operation of the pulse sextupole magnet was successful although some improvement on the injection efficiency is necessary before introducing it to the users operation. The ring is routinely operated in the top-up injection mode with beam current of 300 mA

STATUS OF UVSOR-III

Abstract UVSOR-III is the 750 MeV synchrotron light source. In 2012, three new components were installed in the storage ring. First one is combined function bending magnets to reduce the emittance from 27.4 nm-rad to 16.9 nm-rad. These magnets can produce dipole, quadrupole and sextupole fields. Second ones are an in-vacuum undulator and a beam line. It was installed at 1.4 m straight section, which is the last section reserved for insertion devices. As a result, UVSOR-III is now equipped with six undulators. It would provide soft Xrays for a scanning transmission X-ray microscope (STXM) beam-line. Last one is a newly designed pulse sextupole magnet at the injection point. This is beneficial to the user experiments in the top-up operation mode. Fine machine tuning is in progress

Bgs1p is responsible for primary septum formation

[EN]Cytokinesis is a crucial event in the cell cycle of all living cells. In fungal cells, it requires coordinated contraction of an actomyosin ring and synthesis of both plasmatic membrane and a septum structure that will constitute the new cell wall end. Schizosaccharomyces pombe contains four essential putative (1,3)β-D-glucan synthase catalytic subunits, Bgs1p to Bgs4p. Here we examined the function of Bgs1p in septation by studying the lethal phenotypes of bgs1 + shut-off and bgs1 Δ cells and demonstrated that Bgs1p is responsible and essential for linear (1,3)β-D-glucan and primary septum formation. bgs1 + shut-off generates a more than 300-fold Bgs1p reduction, but the septa still present large amounts of disorganized linear (1,3)β-D-glucan and partial primary septa. Conversely, both structures are absent in bgs1 Δ cells, where there is no Bgs1p. The septum analysis of bgs1+-repressed cells indicates that linear (1,3)β-D-glucan is necessary but not sufficient for primary septum formation. Linear (1,3)β-D-glucan is the polysaccharide that specifically interacts with the fluorochrome Calcofluor white in fission yeast. We also show that in the absence of Bgs1p abnormal septa are formed, but the cells cannot separate and eventually die

Estudio del mecanismo de supervivencia en ausencia de la actividad esencial ß-(1-3) glucán sintasa

Trabajo presentado en el XV Congreso Nacional de Micología, celebrado en Valencia (España), del 7 al 9 de septiembre de 202

Fission yeast Ags1 confers the essential septum strength needed for safe gradual cell abscission

[EN]Fungal cytokinesis requires the assembly of a dividing septum wall. In yeast, the septum has to be selectively digested during the critical cell separation process. Fission yeast cell wall alpha (1-3) glucan is essential, but nothing is known about its localization and function inthe cell wall or about cooperation between the alpha - and beta (1-3) glucan synthases Ags1 and Bgs for cell wall and septum assembly. Here, we generate a physiological Ags1-GFP variant and demonstrate a tight colocalization with Bgs1, suggesting a cooperation in the important early steps of septum construction. Moreover, we define the essential functions of alpha(1-3) glucan in septation and cell separation. We show that alpha (1-3) glucan is essential for both secondary septum formation and the primary septum structural strength needed to support the physical forces of the cell turgor pressure during cell separation. Consequently, the absence of Ags1 and therefore alpha(1-3)glucan generates a special and unique side-explosive cell separation due to an instantaneous primary septum tearing caused by the turgor pressure