Shape Optimization Problems for Metric Graphs

We consider the shape optimization problem $$\min\big\{{\mathcal E}(\Gamma)\ :\ \Gamma\in{\mathcal A},\ {\mathcal H}^1(\Gamma)=l\ \big\},$$ where ${\mathcal H}^1$ is the one-dimensional Hausdorff measure and ${\mathcal A}$ is an admissible class of one-dimensional sets connecting some prescribed set of points ${\mathcal D}=\{D_1,\dots,D_k\}\subset{\mathbb R}^d$. The cost functional ${\mathcal E}(\Gamma)$ is the Dirichlet energy of $\Gamma$ defined through the Sobolev functions on $\Gamma$ vanishing on the points $D_i$. We analyze the existence of a solution in both the families of connected sets and of metric graphs. At the end, several explicit examples are discussed.Comment: 23 pages, 11 figures, ESAIM Control Optim. Calc. Var., (to appear

Optimal Potentials For Schrodinger Operators

We consider the Schrodinger operator a given domain. Our goal is to study some optimization problems where an optimal (non-negative) potential V has to be determined in some suitable admissible classes and for some suitable optimization criteria, like the energy or the Dirichlet eigenvalues.Comment: 23 pages, 2 figure

Double Clipping: Less-Biased Variance Reduction in Off-Policy Evaluation

"Clipping" (a.k.a. importance weight truncation) is a widely used variance-reduction technique for counterfactual off-policy estimators. Like other variance-reduction techniques, clipping reduces variance at the cost of increased bias. However, unlike other techniques, the bias introduced by clipping is always a downward bias (assuming non-negative rewards), yielding a lower bound on the true expected reward. In this work we propose a simple extension, called $\textit{double clipping}$, which aims to compensate this downward bias and thus reduce the overall bias, while maintaining the variance reduction properties of the original estimator.Comment: Presented at CONSEQUENCES '23 workshop at RecSys 2023 conference in Singapor

the intra pontide suture zone in the tosya kastamonu area northern turkey

ABSTRACTWe present the first detailed geological map of the tectonic units documented in the easternmost branch of the Intra-Pontide suture (IPS) zone in the Tosya-Kastamonu area (Northern Turkey). The Main Map is at 1:50,000 scale and covers an area of about 350 km2. It derived from 1:25,000 scale classic field mapping and represents a detailed overview of the complexities documented in the IPS zone, a tectonic nappe stack originating from the closure of the Intra-Pontide Oceanic basin and the subsequent collision between the Istanbul-Zonguldak terrane and the Sakarya composite terrane. The map shows the orientations of superposed foliations, fold axes and mineral lineations on the basis of geometric cross-cutting relationships documented within the five tectonic units of the IPS zone and provides information on its present-day architecture resulting from activity of the North Anatolian Fault

Experimental measurements and CFD modelling of hydroxyapatite scaffolds in perfusion bioreactors for bone regeneration

In the field of bone tissue engineering, particular interest is devoted to the development of 3D cultures to study bone cell proliferation under conditions similar to in vivo ones, e.g. by artificially producing mechanical stresses promoting a biological response (mechanotransduction). Of particular relevance in this context are the effects generated by the flow shear stress, which governs the nutrients delivery rate to the growing cells and which can be controlled in perfusion reactors. However, the introduction of 3D scaffolds complicates the direct measurement of the generated shear stress on the adhered cells inside the matrix, thus jeopardizing the potential of using multi-dimensional matrices. In this study, an anisotropic hydroxyapatite-based set of scaffolds is considered as a 3D biomimetic support for bone cells deposition and growth. Measurements of sample-specific flow resistance are carried out using a perfusion system, accompanied by a visual characterization of the material structure. From the obtained results, a subset of three samples is reproduced using 3D-Computational Fluid Dynamics (CFD) techniques and the models are validated by virtually replicating the flow resistance measurement. Once a good agreement is found, the analysis of flow-induced shear stress on the inner B-HA structure is carried out based on simulation results. Finally, a statistical analysis leads to a simplified expression to correlate the flow resistance with the entity and extensions of wall shear stress inside the scaffold. The study applies CFD to overcome the limitations of experiments, allowing for an advancement in multi-dimensional cell cultures by elucidating the flow conditions in 3D reactors

SDN enabled dynamically reconfigurable high capacity optical access architecture for converged services

Dynamically reconfigurable time-division multiplexing (TDM) dense wavelength division multiplexing (DWDM) long-reach passive optical networks (PONs) can support the reduction of nodes and network interfaces by enabling a fully meshed flat optical core. In this paper we demonstrate the flexibility of the TDM-DWDM PON architecture, which can enable the convergence of multiple service types on a single physical layer. Heterogeneous services and modulation formats, i.e. residential 10G PON channels, business 100G dedicated channel and wireless fronthaul, are demonstrated co-existing on the same long reach TDM-DWDM PON system, with up to 100km reach, 512 users and emulated system load of 40 channels, employing amplifier nodes with either erbium doped fiber amplifiers (EDFAs) or semiconductor optical amplifiers (SOAs). For the first time end-to-end software defined networking (SDN) management of the access and core network elements is also implemented and integrated with the PON physical layer in order to demonstrate two service use cases: a fast protection mechanism with end-to-end service restoration in the case of a primary link failure; and dynamic wavelength allocation (DWA) in response to an increased traffic demand

AB012. Transcriptional and chromatin profiling reveals the molecular architecture and druggable vulnerabilities of thymic epithelial tumors (TETs)

Thymic epithelial tumors (TETs) have been profiled to the present moment mainly through several analyses of FFPE samples. Despite the leap forward brought by the TCGA, several questions remain still unsolved. Among these, TETs are characterized by a strong component of immune infiltrate which makes the transcriptomic analyses conducted so far scarcely interpretable to profile stromal subpopulations constitutive of the tumor. Furthermore, rarely correspondent healthy tissue is available due to the lipomatous atrophy of aged thymi. Therefore, the recent report of (I) isolation, (II) propagation (III) and characterization of human thymic epithelial cells (TECs) and their capacity to reconstitute the functional organ ex vivo and in vivo, represents a novel approach to study the biology of both healthy and neoplastic thymi. Human thymic biopsies (both healthy and neoplastic) were digested and plated on a lethally irradiated murine feeder layer. Both RNA-Seq and CUTANDTAG were performed on cultivated TECs at different passages. Cultured TECs were injected with human thymic interstitial cells into rat decellularized scaffolds and cultivated for 10–12 days. sc-RNA Seq is currently being performed on both healthy and neoplastic thymic mini-organs and their correspondent primary tissues. Here show that we successfully cultivated a cohort of 21 clonogenic TECs in vitro including adult neoplastic TECs, their non-tumoral counterpart and pediatric TECs. We show that at the transcriptome level each class of TECs clusters independently and that neoplastic TECs belong to the same cloud independently from thymoma histotype. Around 1,400 differentially expressed genes (DEGs) can be found when comparing adult neoplastic and non-neoplastic counterpart, among which around 70 are transcription factors. Importantly, we prove for the first time that clonogenic TECs derived from TETs can repopulate a decellularized rat scaffold and recreate a 3D architecture mimicking the primary tumor. This work demonstrates that this culture system allows the expansion of clonogenic TECs from both tumor samples and their non-tumoral counterpart. Those cells, when transplanted into decellularized thymi, reproduce the architecture of the primary tissue, showing that TETs contain progenitor/stem epithelial cells. We are currently characterizing TECs at the transcriptomic and epigenomic level with aim of identifying new druggable targets prior to clinical trials

Disciplinary problems among high achiever students: the types and the causes

This qualitative study has been done to 24 teachers and 72 students from various secondary schools in Penang, Malaysia, in order to investigate the effect of between class ability grouping (BCAG) on high achiever secondary school students. Studies reported that BCAG triggered correspondence bias among teachers, which eventually affect them to show different perception and expectations towards high achiever classes (HAC) and low achiever classes (LAC) students. Symbolic interaction theories explained that individuals tend to be affected by others’ expectation, and therefore behave in a way they were expected to. Therefore, according to the previous studies on BCAG, it was assumed that HAC students would achieve better and would not be significantly involved in disciplinary problems. After semi-structured interview had been conducted in order to collect the data, and two-cycled analyses method, namely In-Vivo and Thematic Analyses had been operated in order to analyze the massive amount of qualitative data, the it was discovered that HAC students were involved with disciplinary problems, such as being disrespectful to teachers, paying less attention in the classroom, neglecting assignments and doing external work during classes. Other findings of this study showed that the disciplinary problems among HAC are related to their self-esteem types due to locus of control difference, as well as bigger issues apart from the competition among themselves. School management system, BCAG itself, reciprocal envy between HAC and LAC students, as well as their inclination towards tuition centers contributed to disciplinary problems among HAC students