The Remote-Clique Problem Revisited

Given a positive integer k and a complete graph with non-negative edge weights that satisfy the triangle inequality, the remote-clique problem is to find a subset of k vertices having a maximum-weight induced subgraph. A greedy algorithm for the problem has been shown to have an approximation ratio of 4, but this analysis was not shown to be tight. In this thesis, we present an algorithm called d-Greedy Augment that generalizes this greedy algorithm (they are equivalent when d = 1). We use the technique of factor-revealing linear programs to prove that d-Greedy Augment, which has a running time of O(kdnd ), achieves an approximation ratio of (2k ? 2)/(k + d ? 2). Thus, when d = 1, d-Greedy Augment achieves an approximation ratio of 2 and runs in time O(kn), making it the fastest known 2-approximation for the remote-clique problem. Beyond proving this worst-case result, we also examine the behavior of d-Greedy Augment in practice. First, we provide some theoretical results regarding the expected case performance of d-Greedy Augment on random graphs, and second, we describe data from some experiments that test the performance of d-Greedy Augment and related heuristics

Cavernous malformation hemorrhage due to trans-mural pressure alterations after cerebrospinal fluid diversion: a case report

Background Cavernous malformations are rare cerebral pseudo-vascular lesions with annualized bleeding rates of 0.5–3% in most studies. Of the various explored risk factors for bleeding to date, only prior hemorrhage has shown significant correlation. Case presentation In this case, we describe a 65-year old man with a peri-ventricular atrial cavernous malformation that hemorrhaged after CSF diversion via ventriculoperitoneal shunting. Serial imaging showed that bleeding continued until the shunt was revised with a programmable valve set at maximum resistance with the addition of a gravitational unit, thereby lowering the trans-mural pressure differential across the cavernous malformation. Conclusions Given that other vascular lesions are subject to hemorrhage from alterations in trans-mural pressure dynamics, we hypothesize that cavernous malformations are similarly affected by trans-mural pressure gradients as they are composed of primitive vascular elements. This hypothesis is corroborated by the temporal correlation of interventions, imaging, and exam findings in the present case, and suggests a potentially important risk factor for hemorrhage in CM patients that affects prognostication and management

Re-thinking the validity of the past. Deconstructing what authenticity and integrity mean to the fruition of cultural heritage

[EN] There is a lively ongoing debate on Critical Heritage Studies and the Authorised Heritage Discourse, but quite a few authors have viewed the issue from a canonical perspective where the wider Cultural Built Heritage visual experience is assessed and valued in relation with authenticity and integrity. The terms static authenticity and dynamic authenticity appear in this text as dependent on heritage connectivity. Two main arguments are developed in this study. Firstly, a general overview of the context is proposed in order to understand the vernacular internationally. Secondly, the article offers an inside view intended to provide an accurate interpretation of how the vernacular is scrutinised and understood. A fundamental issue discussed in this paper is how cultural heritage is ruled, protected, enhanced, experienced and managed on different scales.This research has been developed thanks to the funds of the project “World Heritage Cultural Landscapes List. Keys fortheiridentification and criteria for their management” from the Ministry of Economy and Competitiveness in Spain, MINECO. CSO2015.65787-C6-6-PGarcía-Esparza, JA. (2016). Re-thinking the validity of the past. Deconstructing what authenticity and integrity mean to the fruition of cultural heritage. VITRUVIO - International Journal of Architectural Technology and Sustainability. 1(1):21-34. https://doi.org/10.4995/vitruvio-ijats.2016.4595SWORD21341

Multi-Domain Cognitive Assessment of Male Mice Shows Space Radiation Is Not Harmful to High-Level Cognition and Actually Improves Pattern Separation

Astronauts on interplanetary missions - such as to Mars - will be exposed to space radiation, a spectrum of highly-charged, fast-moving particles that includes 56Fe and 28Si. Earth-based preclinical studies show space radiation decreases rodent performance in low- and some high-level cognitive tasks. Given astronaut use of touchscreen platforms during training and space flight and given the ability of rodent touchscreen tasks to assess functional integrity of brain circuits and multiple cognitive domains in a non-aversive way, here we exposed 6-month-old C57BL/6J male mice to whole-body space radiation and subsequently assessed them on a touchscreen battery. Relative to Sham treatment, 56Fe irradiation did not overtly change performance on tasks of visual discrimination, reversal learning, rule-based, or object-spatial paired associates learning, suggesting preserved functional integrity of supporting brain circuits. Surprisingly, 56Fe irradiation improved performance on a dentate gyrus-reliant pattern separation task; irradiated mice learned faster and were more accurate than controls. Improved pattern separation performance did not appear to be touchscreen-, radiation particle-, or neurogenesis-dependent, as 56Fe and 28Si irradiation led to faster context discrimination in a non-touchscreen task and 56Fe decreased new dentate gyrus neurons relative to Sham. These data urge revisitation of the broadly-held view that space radiation is detrimental to cognition

Gene expression profile predicts outcome after anthracycline-based adjuvant chemotherapy in early breast cancer

International audiencePrognosis of early beast cancer is heterogeneous. Today, no histoclinical or biological factor predictive for clinical outcome after adjuvant anthracycline-based chemotherapy (CT) has been validated and introduced in routine use. Using DNA microarrays, we searched for a gene expression signature associated with metastatic relapse after adjuvant anthracycline-based CT without taxane. We profiled a multicentric series of 595 breast cancers including 498 treated with such adjuvant CT. The identification of the prognostic signature was done using a metagene-based supervised approach in a learning set of 323 patients. The signature was then tested on an independent validation set comprising 175 similarly treated patients, 128 of them from the PACS01 prospective clinical trial. We identified a 3-metagene predictor of metastatic relapse in the learning set, and confirmed its independent prognostic impact in the validation set. In multivariate analysis, the predictor outperformed the individual current prognostic factors, as well as the Nottingham Prognostic Index-based classifier, both in the learning and the validation sets, and added independent prognostic information. Among the patients treated with adjuvant anthracycline-based CT, with a median follow-up of 68 months, the 5-year metastasis-free survival was 82% in the "good-prognosis" group and 56% in the "poor-prognosis" group. Our predictor refines the prediction of metastasis-free survival after adjuvant anthracycline-based CT and might help tailoring adjuvant CT regimens

First Plant Cell Atlas symposium report

The Plant Cell Atlas (PCA) community hosted a virtual symposium on December 9 and 10, 2021 on single cell and spatial omics technologies. The conference gathered almost 500 academic, industry, and government leaders to identify the needs and directions of the PCA community and to explore how establishing a data synthesis center would address these needs and accelerate progress. This report details the presentations and discussions focused on the possibility of a data synthesis center for a PCA and the expected impacts of such a center on advancing science and technology globally. Community discussions focused on topics such as data analysis tools and annotation standards; computational expertise and cyber-infrastructure; modes of community organization and engagement; methods for ensuring a broad reach in the PCA community; recruitment, training, and nurturing of new talent; and the overall impact of the PCA initiative. These targeted discussions facilitated dialogue among the participants to gauge whether PCA might be a vehicle for formulating a data synthesis center. The conversations also explored how online tools can be leveraged to help broaden the reach of the PCA (i.e., online contests, virtual networking, and social media stakeholder engagement) and decrease costs of conducting research (e.g., virtual REU opportunities). Major recommendations for the future of the PCA included establishing standards, creating dashboards for easy and intuitive access to data, and engaging with a broad community of stakeholders. The discussions also identified the following as being essential to the PCA’s success: identifying homologous cell-type markers and their biocuration, publishing datasets and computational pipelines, utilizing online tools for communication (such as Slack), and user-friendly data visualization and data sharing. In conclusion, the development of a data synthesis center will help the PCA community achieve these goals by providing a centralized repository for existing and new data, a platform for sharing tools, and new analytical approaches through collaborative, multidisciplinary efforts. A data synthesis center will help the PCA reach milestones, such as community-supported data evaluation metrics, accelerating plant research necessary for human and environmental health

Enhancing easy-plane anisotropy in bespoke Ni(II) quantum magnets

We examine the crystal structures and magnetic properties of several S = 1 Ni(II) coordination compounds, molecules and polymers, that include the bridging ligands HF2-, AF62- (A = Ti, Zr) and pyrazine or non-bridging ligands F-, SiF62-, glycine, H2O, 1-vinylimidazole, 4-methylpyrazole and 3-hydroxypyridine. Pseudo-octahedral NiN4F2, NiN4O2 or NiN4OF cores consist of equatorial Ni-N bonds that are equal to or slightly longer than the axial Ni-Lax bonds. By design, the zero-field splitting (D) is large in these systems and, in the presence of substantial exchange interactions (J), can be difficult to discriminate from magnetometry measurements on powder samples. Thus, we relied on pulsed-field magnetization in those cases and employed electron-spin resonance (ESR) to confirm D when J 0) and range from ≈ 8-25 K. This work reveals a linear correlation between the ratio d(Ni-Lax)/d(Ni-Neq) and D although the ligand spectrochemical properties may also be important. We assert that this relationship allows us to predict the type of magnetocrystalline anisotropy in tailored Ni(II) quantum magnets