1,620 research outputs found

    Conditioned by Dress – The Relationship between Mind, Fashion, Film & Performance.

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    This is the first monograph in the Pocket Book Series Practices of Transdisciplinarity, a co-publishing collaboration between the ArtEZ Academy in the Netherlands and the London College of Fashion. 'Practices of Transdisciplinarity' examines creative research practices that cross the traditional boundaries assigned to art and design disciplines. Anna-Nicole Ziesche's: Conditioned by Dress - The Relationship between Mind, Fashion, Film and Performance' opens the series. This combined visual and text-based publication is the first book to present an overview of Anna-Nicole Ziesche’s films. Her early work investigates methods for composing fashion ‘looks’, using simple film editing techniques to manipulate, magnify and repeat the decorative details of cloth onto the body. We discover her unique research process that uses story telling and performance to explore the relationship between self-perception and dress. Anna-Nicole is also a sculptor; she re-constructs her dreams, building installations in which she subjects the body to poetic narratives inspired by her experiences of fashion. Within these installations Anna-Nicole and her ‘dressed’ characters perform both physically and psychologically. Film and photography are mediums where "to dress" takes on a new meaning. [from the Foreword, by Lucy Orta

    Search for massive protostar candidates in the southern hemisphere: II. Dust continuum emission

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    In an ongoing effort to identify and study high-mass protostellar candidates we have observed in various tracers a sample of 235 sources selected from the IRAS Point Source Catalog, mostly with dec < -30 deg, with the SEST antenna at millimeter wavelengths. The sample contains 142 Low sources and 93 High, which are believed to be in different evolutionary stages. Both sub-samples have been studied in detail by comparing their physical properties and morphologies. Massive dust clumps have been detected in all but 8 regions, with usually more than one clump per region. The dust emission shows a variety of complex morphologies, sometimes with multiple clumps forming filaments or clusters. The mean clump has a linear size of ~0.5 pc, a mass of ~320 Msolar for a dust temperature Td=30 K, an H_2 density of 9.5E5 cm-3, and a surface density of 0.4 g cm-2. The median values are 0.4 pc, 102 Msolar, 4E4 cm-3, and 0.14 g cm-2, respectively. The mean value of the luminosity-to-mass ratio, L/M ~99 Lsolar/Msolar, suggests that the sources are in a young, pre-ultracompact HII phase. We have compared the millimeter continuum maps with images of the mid-IR MSX emission, and have discovered 95 massive millimeter clumps non-MSX emitters, either diffuse or point-like, that are potential prestellar or precluster cores. The physical properties of these clumps are similar to those of the others, apart from the mass that is ~3 times lower than for clumps with MSX counterpart. Such a difference could be due to the potential prestellar clumps having a lower dust temperature. The mass spectrum of the clumps with masses above M ~100 Msolar is best fitted with a power-law dN/dM proportional to M-alpha with alpha=2.1, consistent with the Salpeter (1955) stellar IMF, with alpha=2.35.Comment: 83 pages, 10 figures, 3 tables. Accepted for publication by A&A. The full paper, including Fig.2 with the maps of all the individual regions, complete Tables 1 and 2 can be found at http://www.arcetri.astro.it/~starform/publ2005.ht

    BMP is an important regulator of proepicardial identity in the chick embryo

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    AbstractThe proepicardium (PE) is a transient structure formed by pericardial coelomic mesothelium at the venous pole of the embryonic heart and gives rise to several cell types of the mature heart. In order to study PE development in chick embryos, we have analyzed the expression pattern of the marker genes Tbx18, Wt1, and Cfc. During PE induction, the three marker genes displayed a left–right asymmetric expression pattern. In each case, expression on the right side was stronger than on the left side. The left–right asymmetric gene expression observed here is in accord with the asymmetric formation of the proepicardium in the chick embryo. While initially the marker genes were expressed in the primitive sinus horn, subsequently, expression became confined to the PE mesothelium. In order to search for signaling factors involved in PE development, we studied Bmp2 and Bmp4 expression. Bmp2 was bilaterally expressed in the sinus venosus. In contrast, Bmp4 expression was initially expressed unilaterally in the right sinus horn and subsequently in the PE. In order to assess its functional role, BMP signaling was experimentally modulated by supplying exogenous BMP2 and by inhibiting endogenous BMP signaling through the addition of Noggin. Both supplying BMP and blocking BMP signaling resulted in a loss of PE marker gene expression. Surprisingly, both experimental situations lead to cardiac myocyte formation in the PE cultures. Careful titration experiments with exogenously added BMP2 or Noggin revealed that PE-specific marker gene expression depends on a low level of BMP signaling. Implantation of BMP2-secreting cells or beads filled with Noggin protein into the right sinus horn of HH stage 11 embryos resulted in downregulation of Tbx18 expression, corresponding to the results of the explant assay. Thus, a distinct level of BMP signaling is required for PE formation in the chick embryo

    Deterministic Fully Dynamic SSSP and More

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    We present the first non-trivial fully dynamic algorithm maintaining exact single-source distances in unweighted graphs. This resolves an open problem stated by Sankowski [COCOON 2005] and van den Brand and Nanongkai [FOCS 2019]. Previous fully dynamic single-source distances data structures were all approximate, but so far, non-trivial dynamic algorithms for the exact setting could only be ruled out for polynomially weighted graphs (Abboud and Vassilevska Williams, [FOCS 2014]). The exact unweighted case remained the main case for which neither a subquadratic dynamic algorithm nor a quadratic lower bound was known. Our dynamic algorithm works on directed graphs, is deterministic, and can report a single-source shortest paths tree in subquadratic time as well. Thus we also obtain the first deterministic fully dynamic data structure for reachability (transitive closure) with subquadratic update and query time. This answers an open problem of van den Brand, Nanongkai, and Saranurak [FOCS 2019]. Finally, using the same framework we obtain the first fully dynamic data structure maintaining all-pairs (1+ϵ)(1+\epsilon)-approximate distances within non-trivial sub-nωn^\omega worst-case update time while supporting optimal-time approximate shortest path reporting at the same time. This data structure is also deterministic and therefore implies the first known non-trivial deterministic worst-case bound for recomputing the transitive closure of a digraph.Comment: Extended abstract to appear in FOCS 202

    Fast Deterministic Fully Dynamic Distance Approximation

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    In this paper, we develop deterministic fully dynamic algorithms for computing approximate distances in a graph with worst-case update time guarantees. In particular, we obtain improved dynamic algorithms that, given an unweighted and undirected graph G=(V,E)G=(V,E) undergoing edge insertions and deletions, and a parameter 0<ϵ1 0 < \epsilon \leq 1 , maintain (1+ϵ)(1+\epsilon)-approximations of the stst-distance between a given pair of nodes s s and t t , the distances from a single source to all nodes ("SSSP"), the distances from multiple sources to all nodes ("MSSP"), or the distances between all nodes ("APSP"). Our main result is a deterministic algorithm for maintaining (1+ϵ)(1+\epsilon)-approximate stst-distance with worst-case update time O(n1.407)O(n^{1.407}) (for the current best known bound on the matrix multiplication exponent ω\omega). This even improves upon the fastest known randomized algorithm for this problem. Similar to several other well-studied dynamic problems whose state-of-the-art worst-case update time is O(n1.407)O(n^{1.407}), this matches a conditional lower bound [BNS, FOCS 2019]. We further give a deterministic algorithm for maintaining (1+ϵ)(1+\epsilon)-approximate single-source distances with worst-case update time O(n1.529)O(n^{1.529}), which also matches a conditional lower bound. At the core, our approach is to combine algebraic distance maintenance data structures with near-additive emulator constructions. This also leads to novel dynamic algorithms for maintaining (1+ϵ,β)(1+\epsilon, \beta)-emulators that improve upon the state of the art, which might be of independent interest. Our techniques also lead to improved randomized algorithms for several problems such as exact stst-distances and diameter approximation.Comment: Changes to the previous version: improved bounds for approximate st distances using new algebraic data structure

    Algorithm and Hardness for Dynamic Attention Maintenance in Large Language Models

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    Large language models (LLMs) have made fundamental changes in human life. The attention scheme is one of the key components over all the LLMs, such as BERT, GPT-1, Transformers, GPT-2, 3, 3.5 and 4. Inspired by previous theoretical study of static version of the attention multiplication problem [Zandieh, Han, Daliri, and Karbasi arXiv 2023, Alman and Song arXiv 2023]. In this work, we formally define a dynamic version of attention matrix multiplication problem. There are matrices Q,K,VRn×dQ,K, V \in \mathbb{R}^{n \times d}, they represent query, key and value in LLMs. In each iteration we update one entry in KK or VV. In the query stage, we receive (i,j)[n]×[d](i,j) \in [n] \times [d] as input, and want to answer (D1AV)i,j(D^{-1} A V)_{i,j}, where A:=exp(QK)Rn×nA:=\exp(QK^\top) \in \mathbb{R}^{n \times n} is a square matrix and D:=diag(A1n)Rn×nD := \mathrm{diag}(A {\bf 1}_n) \in \mathbb{R}^{n \times n} is a diagonal matrix. Here 1n{\bf 1}_n denote a length-nn vector that all the entries are ones. We provide two results: an algorithm and a conditional lower bound. \bullet On one hand, inspired by the lazy update idea from [Demetrescu and Italiano FOCS 2000, Sankowski FOCS 2004, Cohen, Lee and Song STOC 2019, Brand SODA 2020], we provide a data-structure that uses O(nω(1,1,τ)τ)O(n^{\omega(1,1,\tau)-\tau}) amortized update time, and O(n1+τ)O(n^{1+\tau}) worst-case query time. \bullet On the other hand, show that unless the hinted matrix vector multiplication conjecture [Brand, Nanongkai and Saranurak FOCS 2019] is false, there is no algorithm that can use both O(nω(1,1,τ)τΩ(1))O(n^{\omega(1,1,\tau) - \tau- \Omega(1)}) amortized update time, and O(n1+τΩ(1))O(n^{1+\tau-\Omega(1)}) worst query time. In conclusion, our algorithmic result is conditionally optimal unless hinted matrix vector multiplication conjecture is false

    Interrelation of ST-segment depression during bicycle ergometry and extent of myocardial ischaemia by myocardial perfusion SPECT

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    Purpose: The aim of this study was to compare ST-segment depression (STD) during bicycle ergometry and extent of myocardial ischaemia assessed by myocardial perfusion SPECT (MPS) in a large patient cohort. Methods: Consecutive patients (n = 955) referred for MPS with bicycle ergometry and interpretable stress ECG were evaluated with respect to ECG and MPS findings of ischaemia. The maximal STD was recorded and exercise ECG was considered ischaemic if STD was horizontal or downsloping (≥1mm). MPS was interpreted using a 20-segment model with a scale of 0 to 4. A summed stress (SSS), summed rest (SRS) and summed difference score (SDS = SSS−SRS, e.g. extent of ischaemia) were derived. Ischaemia was defined as an SDS ≥ 2. Results: An exercise-induced STD was present in 215 patients (22%) and myocardial ischaemia on MPS was present in 366 patients (38%). The extent of ST-segment depression and the number of ECG leads with significant STD were each strongly and significantly associated with increasing severity of ischaemia and the number of coronary territories involved (p < 0.01 for all correlations). Conclusion: These data demonstrate a strong correlation between the extent of STD, number of ischaemic leads and severity of myocardial ischaemia as assessed by MPS during bicycle ergometr
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