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Singlet fission (SF), an exciton-doubling process observed in certain molecular semiconductors where two triplet excitons are generated from one singlet exciton, requires correctly tuned intermolecular coupling to allow separation of the two triplets to different molecular units. We explore this using DNA-encoded assembly of SF-capable pentacenes into discrete π-stacked constructs of defined size and geometry. Precise structural control is achieved via a combination of the DNA duplex formation between complementary single-stranded DNA and the local molecular geometry that directs the SF chromophores into a stable and predictable slip-stacked configuration, as confirmed by molecular dynamics (MD) modeling. Transient electron spin resonance spectroscopy revealed that within these DNA-assembled pentacene stacks, SF evolves via a bound triplet pair quintet state, which subsequently converts into free triplets. SF evolution via a long-lived quintet state sets specific requirements on intermolecular coupling, rendering the quintet spectrum and its zero-field-splitting parameters highly sensitive to intermolecular geometry. We have found that the experimental spectra and zero-field-splitting parameters are consistent with a slight systematic strain relative to the MD-optimized geometry. Thus, the transient electron spin resonance analysis is a powerful tool to test and refine the MD-derived structure models. DNA-encoded assembly of coupled semiconductor molecules allows controlled construction of electronically functional structures, but brings with it significant dynamic and polar disorders. Our findings here of efficient SF through quintet states demonstrate that these conditions still allow efficient and controlled semiconductor operation and point toward future opportunities for constructing functional optoelectronic systems.

Supplemental material, sj-docx-1-tej-10.1177_20417314231169375 for Single-cell RNA-sequence analysis of human bone marrow reveals new targets for isolation of skeletal stem cells using spherical nucleic acids by Elloise Z Matthews, Stuart Lanham, Kate White, Maria-Eleni Kyriazi, Konstantina Alexaki, Afaf H El-Sagheer, Tom Brown, Antonios G Kanaras, Jonathan J West, Ben D MacArthur, Patrick S Stumpf and Richard OC Oreffo in Journal of Tissue Engineering

Large-scale pre-training has recently emerged as a technique for creating capable, general purpose, generative models such as GPT-3, Megatron-Turing NLG, Gopher, and many others. In this paper, we highlight a counterintuitive property of such models and discuss the policy implications of this property. Namely, these generative models have an unusual combination of predictable loss on a broad training distribution (as embodied in their "scaling laws"), and unpredictable specific capabilities, inputs, and outputs. We believe that the high-level predictability and appearance of useful capabilities drives rapid development of such models, while the unpredictable qualities make it difficult to anticipate the consequences of model deployment. We go through examples of how this combination can lead to socially harmful behavior with examples from the literature and real world observations, and we also perform two novel experiments to illustrate our point about harms from unpredictability. Furthermore, we analyze how these conflicting properties combine to give model developers various motivations for deploying these models, and challenges that can hinder deployment. We conclude with a list of possible interventions the AI community may take to increase the chance of these models having a beneficial impact. We intend this paper to be useful to policymakers who want to understand and regulate AI systems, technologists who care about the potential policy impact of their work, and academics who want to analyze, critique, and potentially develop large generative models., Updated to reflect the version submitted (and accepted) to ACM FAccT '22. This update incorporates feedback from peer-review and fixes minor typos. See open access FAccT conference version at: https://dl.acm.org/doi/abs/10.1145/3531146.3533229

Therapies that target the downstream inhibition of gene expression are of great current research significance with considerable efforts now dedicated to the discovery of new antisense oligonucleotides (ASOs). The development of nucleic acid probes targeting DNA, such as triplex-forming oligonucleotides (TFOs),offers an alternative strategy whereby gene expression is directly inhibited at the genomic level. Here, we present a click chemistry strategy for the generation of a new class of cis-platinum(II)-TFO hybrid biomaterial that possess DNA binding and crosslinking activity.

The proposal promotes making the world's fastest open-source solver HiGHS better and describes a plan on how to achieve this. However, the developments require funds which we aim to collect with this proposal. Funds are collected over the Linux Foundation platform and can be tax-deductible. A full proposal with endorsement is available at https://pypsa-meets-africa.github.io/highs.html

Additional file 2: Figure S2. Average deviations from the mean for every considered carrier (solar, wind, battery and hydrogen) and power flows between the different model results respective clustering at a spatial resolution of 1250 nodes for a $$60\%$$ 60 % carbon reduction target compared to 1990s level.

Additional file 4: Figure S4. Average deviations from the mean for different result out-puts as provided. Additional file 2: Fig. S2, here provided for a scenario where nocarbon emissions are allowed.

Renewable generation from wind and solar power is strongly weather-dependent. To plan future sustainable energy systems that are robust to this variability, a better understanding of why and when periods of low wind and solar power output occur is valuable. We call such periods of low wind and solar power output `Dunkelflauten', the German word for dark wind lulls. In this article, we analyse the meteorological conditions during Dunkelflauten in Germany by applying the concept of weather regimes. Weather regimes are quasi-stationary, recurrent, and persistent large-scale circulation patterns which explain multi-day atmospheric variability (5-15 days). We use a regime definition that allows us to distinguish four different types of blocked regimes, characterised by high pressure situations in the North Atlantic-European region. We find that in Germany, Dunkelflauten mainly occur in winter when the solar power output is anyway low and when the wind power output drops for several consecutive days. A high-pressure system over Germany, associated with the European Blocking regime, is responsible for most of the Dunkelflauten. Dunkelflauten during the Greenland Blocking regime are associated with colder temperatures than usual, causing higher electricity demand and presenting a particular challenge as space heating demand electrifies in future. Furthermore, we show that Dunkelflauten occur predominantly when a weather regime is well-established and persists longer than usual. Our study provides novel insight on the occurrence and meteorological characteristics of Dunkelflauten, which is essential for planning resilient energy systems and supporting grid operators to prepare for potential shortages in supply., Comment: 20pages, 11figures, submitted to "Meteorological Applications" by Royal Meteorological Society (https://rmets.onlinelibrary.wiley.com/journal/14698080)

Additional file 1: Figure S1. Correlation factors for every considered carrier (solar, wind, battery and hydrogen) and power flows between the different model results respective clustering at a spatial resolution of 1250 nodes for a $$60\%$$ 60 % carbon reduction target compared to 1990s level.

We describe our early efforts to red team language models in order to simultaneously discover, measure, and attempt to reduce their potentially harmful outputs. We make three main contributions. First, we investigate scaling behaviors for red teaming across 3 model sizes (2.7B, 13B, and 52B parameters) and 4 model types: a plain language model (LM); an LM prompted to be helpful, honest, and harmless; an LM with rejection sampling; and a model trained to be helpful and harmless using reinforcement learning from human feedback (RLHF). We find that the RLHF models are increasingly difficult to red team as they scale, and we find a flat trend with scale for the other model types. Second, we release our dataset of 38,961 red team attacks for others to analyze and learn from. We provide our own analysis of the data and find a variety of harmful outputs, which range from offensive language to more subtly harmful non-violent unethical outputs. Third, we exhaustively describe our instructions, processes, statistical methodologies, and uncertainty about red teaming. We hope that this transparency accelerates our ability to work together as a community in order to develop shared norms, practices, and technical standards for how to red team language models.

Additional file 3: Figure S3. Correlation factors as provided in Additional file 1: Fig. S1, here provided for a scenario where no carbon emissions are allowed

As language models (LMs) scale, they develop many novel behaviors, good and bad, exacerbating the need to evaluate how they behave. Prior work creates evaluations with crowdwork (which is time-consuming and expensive) or existing data sources (which are not always available). Here, we automatically generate evaluations with LMs. We explore approaches with varying amounts of human effort, from instructing LMs to write yes/no questions to making complex Winogender schemas with multiple stages of LM-based generation and filtering. Crowdworkers rate the examples as highly relevant and agree with 90-100% of labels, sometimes more so than corresponding human-written datasets. We generate 154 datasets and discover new cases of inverse scaling where LMs get worse with size. Larger LMs repeat back a dialog user's preferred answer ("sycophancy") and express greater desire to pursue concerning goals like resource acquisition and goal preservation. We also find some of the first examples of inverse scaling in RL from Human Feedback (RLHF), where more RLHF makes LMs worse. For example, RLHF makes LMs express stronger political views (on gun rights and immigration) and a greater desire to avoid shut down. Overall, LM-written evaluations are high-quality and let us quickly discover many novel LM behaviors., Comment: for associated data visualizations, see https://www.evals.anthropic.com/model-written/ for full datasets, see https://github.com/anthropics/evals

Spatially highly-resolved capacity expansion models are often simplified to a lower spatial resolution because they are computationally intensive. The simplification mixes sites with different renewable features while ignoring transmission lines that can cause congestion. As a consequence, the results may represent an infeasible system when the capacities are fed back at higher spatial detail. Thus far there has been no detailed investigation of how to disaggregate results and whether the spatially highly-resolved disaggregated model is feasible. This is challenging since there is no unique way to invert the clustering. This article is split into two parts to tackle these challenges. First, methods to disaggregate spatially low-resolved results are presented: (a) an uniform distribution of regional results across its original highly-resolved regions, (b) a re-optimisation for each region separately, (c) an approach that minimises the "excess electricity". Second, the resulting highly-resolved models' feasibility is investigated by running an operational dispatch. While re-optimising yields the best results, the third inverse method provides comparable results for less computational effort. Feasibility-wise, the study design strengthens that modelling countries by single regions is insufficient. State-of-the-art reduced models with 100-200 regions for Europe still yield 3%-7% of load-shedding, depending on model resolution and inverse method., Comment: Post-print

Davison, Anna M., Brown, Tom W., Arrivillaga, Cristina (2020): Notes on the diet and reproduction of the bark scorpion Centruroides gracilis (Scorpiones: Buthidae) on Utila Island, Honduras. Euscorpius 314: 1-7, DOI: http://doi.org/10.5281/zenodo.4648638, {"references":["ARMAS, L. F. de. 1987. Copula multiple en escorpiones (Arachnida: Scorpiones). Miscellanea Zoologica, 30: 1-2.","ARMAS, L. F. de, D. L. SARMIENTO & E. FLOREZ D. 2012. Composicion del genero Centruroides Marx, 1980 (Scorpiones: Buthidae) en Colombia, con la descripcion de una nueva especie. Boletin de la Sociedad Entomologica Aragonesa, 50: 105-114.","BENDER, G. L. 1959. Studies on a synthetic diet for the scorpion, Centruroides sculpturatus. Annals of the New York Academy of Sciences, 77(2): 262-266.","BROWN, T. & C. ARRIVILLAGA. 2019 Notes on Phyllodactylus palmeus (Dixon, 1968) (Squamata; Gekkonidae); A case of diurnal refuge co-inhabitancy with Centruroides gracilis (Latreille, 1804) (Scorpiones: Buthidae) on Utila Island, Honduras. Captive & Field Herpetology 3 (1): 29-33.","CARLSON, B. E., S. McGINLEY, & M. P. ROWE. 2014. Meek males and fighting females: Sexually-dimorphic antipredator behavior and locomotor performance is explained by morphology in Bark Scorpions (Centruroides vittatus). PLoS ONE: 9(5): e97648.","DOR, A., S. CALME & Y. HENAUT. 2011. Predatory interactions between Centruroides scorpions and the tarantula Brachypelma vagans. The Journal of Arachnology, 39(1): 201-204.","FARLEY, R. D. 2008. Development of respiratory structures in embryos and first and second instars of the bark scorpion, Centruroides gracilis (Scorpiones: Buthidae). Journal of Morphology, 269: 1134-1156.","FRANCKE, O. F. & S. K. JONES. 1982. The life history of Centruroides gracilis (Scorpiones, Buthidae). The Journal of Arachnology, 10: 22-239.","LOURENCO, W. R. & CUELLAR, O. 1995. Scorpions, scorpionism, life history strategies and parthenogenesis. Journal of Venomous Animals and Toxins, 1(2): 51-62.","McCORMACK, S. J. & G. A. POLIS. 1990. Prey, predators, and parasites. Pp. 294-320 in G. A. Polis (ed.) Biology of Scorpions. Stanford University Press, Stanford, California.","NENTWIG, W. 2018. Human health impact by alien spiders and scorpions. Pp. 34-49 in G. Mazza & E. Tricarico (eds.) Invasive Species and Human Health. Oxfordshire: CABI.","POLIS, G. A. 1980. The effect of cannibalism on the demography and activity of a natural population of desert scorpions. Behavioral Ecology and Sociobiology, 7(1): 23-35.","POLIS, G. A. & M. MOHNAC. 1990. Mating by female scorpions while still carrying young. The Journal of Arachnology, 18(3): 363-364.","POLIS, G. A. & W. D. SISSOM. 1990. Life history. Pp. 161- 223 in G. A. Polis (ed.) Biology of Scorpions. Stanford University Press, Stanford, California.","RODRIGUEZ-CABRERA, T. M., R. TERUEL & E. M. SAVALL. 2020. Scorpion predation in Cuba: New cases and a review. Euscorpius, 306: 1-7.","SAGASTUME-ESPINOZA, K., S. J. LONGHORN & C. E. SANTIBANEZ-LOPEZ. 2015. A new scorpion species of genus Diplocentrus Peters, 1861 (Scorpiones: Diplocentridae) endemic to Islas de la Bahia, Honduras. Comptes Rendus Biologies, 338: 502-510.","SANTIBANEZ-LOPEZ, C. E., O. F. FRANCKE, C. URETA & L. D. POSSANI. 2015. Scorpions from Mexico: From species diversity to venom complexity. Toxins, 8(1): 2.","SOLOMON, M. E. 1949. The natural control of animal populations. Journal of Animal Ecology: 18:1-35.","TERUEL, R. & MYERS, B. 2017. A new island species of Centruroides Marx, 1890 (Scorpiones: Buthidae) from the southwestern Caribbean. Euscorpius, 252: 1-14.","TOXINOLOGY, WCH. 2018. Clinical Toxinology Resources: Centruroides gracilis. [Online]. [Accessed: 01/08/ 2019]. Available from: http://www.toxinology.com/","WEIDE, A. 2019. Centruroides gracilis (Latreille, 1804). [Online]. [Accessed: 01/08/2019]. Available from: http:// www.panarthropoda.de/","WILLIAMS, S. C. 1969. Birth activities of some North American scorpions. Proceedings of the California Academy of Science, 37(1): 1-24.","WILLIAMS, S. C. 1987. Scorpion bionomics. Annual Review of Entomology, 32: 275-295."]}

We identify empirical scaling laws for the cross-entropy loss in four domains: generative image modeling, video modeling, multimodal image$\leftrightarrow$text models, and mathematical problem solving. In all cases autoregressive Transformers smoothly improve in performance as model size and compute budgets increase, following a power-law plus constant scaling law. The optimal model size also depends on the compute budget through a power-law, with exponents that are nearly universal across all data domains. The cross-entropy loss has an information theoretic interpretation as $S($True$) + D_{\mathrm{KL}}($True$||$Model$)$, and the empirical scaling laws suggest a prediction for both the true data distribution's entropy and the KL divergence between the true and model distributions. With this interpretation, billion-parameter Transformers are nearly perfect models of the YFCC100M image distribution downsampled to an $8\times 8$ resolution, and we can forecast the model size needed to achieve any given reducible loss (ie $D_{\mathrm{KL}}$) in nats/image for other resolutions. We find a number of additional scaling laws in specific domains: (a) we identify a scaling relation for the mutual information between captions and images in multimodal models, and show how to answer the question "Is a picture worth a thousand words?"; (b) in the case of mathematical problem solving, we identify scaling laws for model performance when extrapolating beyond the training distribution; (c) we finetune generative image models for ImageNet classification and find smooth scaling of the classification loss and error rate, even as the generative loss levels off. Taken together, these results strengthen the case that scaling laws have important implications for neural network performance, including on downstream tasks., Comment: 20+17 pages, 33 figures; added appendix with additional language results

Recent work has demonstrated substantial gains on many NLP tasks and benchmarks by pre-training on a large corpus of text followed by fine-tuning on a specific task. While typically task-agnostic in architecture, this method still requires task-specific fine-tuning datasets of thousands or tens of thousands of examples. By contrast, humans can generally perform a new language task from only a few examples or from simple instructions - something which current NLP systems still largely struggle to do. Here we show that scaling up language models greatly improves task-agnostic, few-shot performance, sometimes even reaching competitiveness with prior state-of-the-art fine-tuning approaches. Specifically, we train GPT-3, an autoregressive language model with 175 billion parameters, 10x more than any previous non-sparse language model, and test its performance in the few-shot setting. For all tasks, GPT-3 is applied without any gradient updates or fine-tuning, with tasks and few-shot demonstrations specified purely via text interaction with the model. GPT-3 achieves strong performance on many NLP datasets, including translation, question-answering, and cloze tasks, as well as several tasks that require on-the-fly reasoning or domain adaptation, such as unscrambling words, using a novel word in a sentence, or performing 3-digit arithmetic. At the same time, we also identify some datasets where GPT-3's few-shot learning still struggles, as well as some datasets where GPT-3 faces methodological issues related to training on large web corpora. Finally, we find that GPT-3 can generate samples of news articles which human evaluators have difficulty distinguishing from articles written by humans. We discuss broader societal impacts of this finding and of GPT-3 in general., Comment: 40+32 pages

We study empirical scaling laws for language model performance on the cross-entropy loss. The loss scales as a power-law with model size, dataset size, and the amount of compute used for training, with some trends spanning more than seven orders of magnitude. Other architectural details such as network width or depth have minimal effects within a wide range. Simple equations govern the dependence of overfitting on model/dataset size and the dependence of training speed on model size. These relationships allow us to determine the optimal allocation of a fixed compute budget. Larger models are significantly more sample-efficient, such that optimally compute-efficient training involves training very large models on a relatively modest amount of data and stopping significantly before convergence., Comment: 19 pages, 15 figures

We expand the renewable technology model palette and present a validated high resolution hydro power time series model for energy systems analysis. Among the popular renewables, hydroelectricity shows unique storage-like flexibility, which is particularly important given the high variability of wind and solar power. Often limited by data availability or computational performance, a high resolution, globally applicable and validated hydro power time series model has not been available. For a demonstration, we focus on 41 Chinese reservoir-based hydro stations as a demo, determine their upstream basin areas, estimate their inflow based on gridded surface runoff data and validate their daily inflow time series in terms of both flow volume and potential power generation. Furthermore, we showcase an application of these time series with hydro cascades in energy system long term investment planning. Our method's novelty lies in:it is based on highly resolved spatial-temporal datasets; both data and algorithms used here are globally applicable; it includes a hydro cascade model that can be integrated into energy system simulations., Comment: arXiv admin note: text overlap with arXiv:1810.10347

We study the transfer of adversarial robustness of deep neural networks between different perturbation types. While most work on adversarial examples has focused on $L_\infty$ and $L_2$-bounded perturbations, these do not capture all types of perturbations available to an adversary. The present work evaluates 32 attacks of 5 different types against models adversarially trained on a 100-class subset of ImageNet. Our empirical results suggest that evaluating on a wide range of perturbation sizes is necessary to understand whether adversarial robustness transfers between perturbation types. We further demonstrate that robustness against one perturbation type may not always imply and may sometimes hurt robustness against other perturbation types. In light of these results, we recommend evaluation of adversarial defenses take place on a diverse range of perturbation types and sizes., Comment: 11 pages, 6 figures

Reward learning enables the application of reinforcement learning (RL) to tasks where reward is defined by human judgment, building a model of reward by asking humans questions. Most work on reward learning has used simulated environments, but complex information about values is often expressed in natural language, and we believe reward learning for language is a key to making RL practical and safe for real-world tasks. In this paper, we build on advances in generative pretraining of language models to apply reward learning to four natural language tasks: continuing text with positive sentiment or physically descriptive language, and summarization tasks on the TL;DR and CNN/Daily Mail datasets. For stylistic continuation we achieve good results with only 5,000 comparisons evaluated by humans. For summarization, models trained with 60,000 comparisons copy whole sentences from the input but skip irrelevant preamble; this leads to reasonable ROUGE scores and very good performance according to our human labelers, but may be exploiting the fact that labelers rely on simple heuristics.

We explore a new way to evaluate generative models using insights from evaluation of competitive games between human players. We show experimentally that tournaments between generators and discriminators provide an effective way to evaluate generative models. We introduce two methods for summarizing tournament outcomes: tournament win rate and skill rating. Evaluations are useful in different contexts, including monitoring the progress of a single model as it learns during the training process, and comparing the capabilities of two different fully trained models. We show that a tournament consisting of a single model playing against past and future versions of itself produces a useful measure of training progress. A tournament containing multiple separate models (using different seeds, hyperparameters, and architectures) provides a useful relative comparison between different trained GANs. Tournament-based rating methods are conceptually distinct from numerous previous categories of approaches to evaluation of generative models, and have complementary advantages and disadvantages.

Supplemental Material, DS1_VET_10.1177_0192623318789130 for The Antitussive Benzonatate Is Not Tumorigenic in Rodent Carcinogenicity Studies by Steve Teo, Madhav Paranjpe, Marie Mckeon, Peter Mann, Sophie Lee, Richard LaRock, and Tom Brown in Toxicologic Pathology

We use three ensemble members of the EURO-CORDEX project and their data on surface wind speeds, solar irradiation as well as water runoff with a spatial resolution of 12 km and a temporal resolution of 3 hours under representative concentration pathway 8.5 (associated with a temperature increase of 2.6 to 4.8 degrees C until the end of the century) until 2100 to investigate the impact of climate change on wind, solar and hydro resources and consequently on a highly renewable and cost-optimal European power system. The weather data is transformed into power, different aspects such as capacity factors and correlation lengths are investigated and the resulting implications for the European power system are discussed. In addition, we compare a 30-node model of Europe with historical and climate change-affected data, where investments in generation, transmission and storage facilities are optimised for deep carbon dioxide reductions. Differences in capacity factors among European countries are more strongly emphasized at the end of the century compared to historic data. This results in a significantly increased photovoltaic share in the cost-optimal power system. System costs increase by 5% until the end of the century and the impact of climate change on these costs is of similar magnitude as differences between the ensemble members.

For sophisticated reinforcement learning (RL) systems to interact usefully with real-world environments, we need to communicate complex goals to these systems. In this work, we explore goals defined in terms of (non-expert) human preferences between pairs of trajectory segments. We show that this approach can effectively solve complex RL tasks without access to the reward function, including Atari games and simulated robot locomotion, while providing feedback on less than one percent of our agent's interactions with the environment. This reduces the cost of human oversight far enough that it can be practically applied to state-of-the-art RL systems. To demonstrate the flexibility of our approach, we show that we can successfully train complex novel behaviors with about an hour of human time. These behaviors and environments are considerably more complex than any that have been previously learned from human feedback.

For positive integers $s$ and $k_1, k_2, ..., k_s$, let $w(k_1,k_2,...,k_s)$ be the minimum integer $n$ such that any $s$-coloring $\{1,2,...,n\} \to \{1,2,...,s\}$ admits a $k_i$-term arithmetic progression of color $i$ for some $i$, $1 \leq i \leq s$. In the case when $k_1=k_2=...=k_s=k$ we simply write $w(k;s)$. That such a minimum integer exists follows from van der Waerden's theorem on arithmetic progressions. In the present paper we give a lower bound for $w(k,m)$ for each fixed $m$. We include a table with values of $w(k,3)$ which match this lower bound closely for $5 \leq k \leq 16$. We also give an upper bound for $w(k,4)$, an upper bound for $w(4;s)$, and a lower bound for $w(k;s)$ for an arbitrary fixed $k$. We discuss a number of other functions that are closely related to the van der Waerden function., Comment: 13 pages

We describe a particular partition of the non-negative integers which consists of infinitely many translates of an infinite set. This partition is used to show that a certain van der Waerden-like theorem has no simple canonical version. The partition is also used to give a lower bound for one of the classical van der Waerden functions, namely w(3;m),the smallest positive integer such that every m-coloring of [1,w(3;m)] produces a monochromatic 3-term arithmetic progression. Several open questions are mentioned.

It is known that if $N$ is finitely colored, then some color class is piecewise syndetic. (See Definition 1.1 below for a definition of piecewise syndetic.) We generalize this result by considering finite colorings of the set of all finite subsets of $N$ . The monochromatic objects obtained are “$d$-copies” of arbitrary finite forests and arbitrary infinite forests of finite height. Van der Waerden’s theorem on arithmetic progressions is generalized in a similar way. Ramsey’s theorem and van der Waerden’s theorem are used in some of the proofs.

We determine the velocity vector of M31 with respect to the Milky Way and use this to constrain the mass of the Local Group, based on HST proper-motion measurements presented in Paper I. We construct N-body models for M31 to correct the measurements for the contributions from stellar motions internal to M31. We also estimate the center-of-mass motion independently, using the kinematics of satellite galaxies of M31 and the Local Group. All estimates are mutually consistent, and imply a weighted average M31 heliocentric transverse velocity of (v_W,v_N) = (-125.2+/-30.8, -73.8+/-28.4) km/s. We correct for the reflex motion of the Sun using the most recent insights into the solar motion within the Milky Way. This implies a radial velocity of M31 with respect to the Milky Way of V_rad = -109.3+/-4.4 km/s, and a tangential velocity V_tan = 17.0 km/s (, 38 pages, 4 figures, to be published in ApJ. Version with high resolution figures and N-body movies available at http://www.stsci.edu/~marel/M31 . Press materials, graphics, and visualizations available at http://hubblesite.org/newscenter/archive/releases/2012/20

1. Case of "rheumatic heart disease (initial incompetence and ... stenosis) with auricular fibrillation 2. Case of "coronary occlusion of syphilitic aetiology" 3. Case of acute pericarditis of rheumatic origin 4. Case of "aortic incompetence due to syphilitic aortitis" 5. Case of ... rheumatism with mitral stenosis and incompetence and auricular fibrillation" 6. Case of "essential hypertension" leading to ischaemic changes ... kidneys, heart and brain

Funder: University of Cambridge, Natural photosystems use protein scaffolds to control intermolecular interactions that enable exciton flow, charge generation, and long-range charge separation. In contrast, there is limited structural control in current organic electronic devices such as OLEDs and solar cells. We report here the DNA-encoded assembly of π-conjugated perylene diimides (PDIs) with deterministic control over the number of electronically coupled molecules. The PDIs are integrated within DNA chains using phosphoramidite coupling chemistry, allowing selection of the DNA sequence to either side, and specification of intermolecular DNA hybridization. In this way, we have developed a "toolbox" for construction of any stacking sequence of these semiconducting molecules. We have discovered that we need to use a full hierarchy of interactions: DNA guides the semiconductors into specified close proximity, hydrophobic-hydrophilic differentiation drives aggregation of the semiconductor moieties, and local geometry and electrostatic interactions define intermolecular positioning. As a result, the PDIs pack to give substantial intermolecular π wave function overlap, leading to an evolution of singlet excited states from localized excitons in the PDI monomer to excimers with wave functions delocalized over all five PDIs in the pentamer. This is accompanied by a change in the dominant triplet forming mechanism from localized spin-orbit charge transfer mediated intersystem crossing for the monomer toward a delocalized excimer process for the pentamer. Our modular DNA-based assembly reveals real opportunities for the rapid development of bespoke semiconductor architectures with molecule-by-molecule precision.

Natural photosystems use protein scaffolds to control intermolecular interactions that enable exciton flow, charge generation, and long-range charge separation. In contrast, there is limited structural control in current organic electronic devices such as OLEDs and solar cells. We report here the DNA-encoded assembly of ��-conjugated perylene diimides (PDIs) with deterministic control over the number of electronically coupled molecules. The PDIs are integrated within DNA chains using phosphoramidite coupling chemistry, allowing selection of the DNA sequence to either side, and specification of intermolecular DNA hybridization. In this way, we have developed a "toolbox" for construction of any stacking sequence of these semiconducting molecules. We have discovered that we need to use a full hierarchy of interactions: DNA guides the semiconductors into specified close proximity, hydrophobic-hydrophilic differentiation drives aggregation of the semiconductor moieties, and local geometry and electrostatic interactions define intermolecular positioning. As a result, the PDIs pack to give substantial intermolecular �� wave function overlap, leading to an evolution of singlet excited states from localized excitons in the PDI monomer to excimers with wave functions delocalized over all five PDIs in the pentamer. This is accompanied by a change in the dominant triplet forming mechanism from localized spin-orbit charge transfer mediated intersystem crossing for the monomer toward a delocalized excimer process for the pentamer. Our modular DNA-based assembly reveals real opportunities for the rapid development of bespoke semiconductor architectures with molecule-by-molecule precision., ERC Horizon 2020 (grant agreement No 670405 and No 803326) EPSRC Tier-2 capital grant EP/P020259/1. Winton Advanced Research Programme for the Physics of Sustainability. Simons Foundation (Grant 601946). Swedish research council, Vetenskapsr��det 2018-00238

We report the design and optimisation of novel oligonucleotide substrates for a sensitive fluorescence assay for high-throughput screening and functional studies of the DNA repair enzyme, XPF-ERCC1, with a view to accelerating inhibitor and drug discovery.

We report the design and optimisation of novel oligonucleotide substrates for a sensitive fluorescence assay for high-throughput screening and functional studies of the DNA repair enzyme, XPF-ERCC1, with a view to accelerating inhibitor and drug discovery.

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a set of mission concepts for the next generation of UVOIR space observatory with a primary aperture diameter in the 8-m to 16-m range that will allow us to perform some of the most challenging observations to answer some of our most compelling questions, including "Is there life elsewhere in the Galaxy?" We have identified two different telescope architectures, but with similar optical designs, that span the range in viable technologies. The architectures are a telescope with a monolithic primary mirror and two variations of a telescope with a large segmented primary mirror. This approach provides us with several pathways to realizing the mission, which will be narrowed to one as our technology development progresses. The concepts invoke heritage from HST and JWST design, but also take significant departures from these designs to minimize complexity, mass, or both. Our report provides details on the mission concepts, shows the extraordinary scientific progress they would enable, and describes the most important technology development items. These are the mirrors, the detectors, and the high-contrast imaging technologies, whether internal to the observatory, or using an external occulter. Experience with JWST has shown that determined competitors, motivated by the development contracts and flight opportunities of the new observatory, are capable of achieving huge advances in technical and operational performance while keeping construction costs on the same scale as prior great observatories., Comment: 22 pages, RFI submitted to Astro2010 Decadal Committee

Natural photosystems use protein scaffolds to control intermolecular interactions that enable exciton flow, charge generation, and long-range charge separation. In contrast, there is limited structural control in current organic electronic devices such as OLEDs and solar cells. We report here the DNA-encoded assembly of pi-conjugated perylene diimides (PDIs) with deterministic control over the number of electronically coupled molecules. The PDIs are integrated within DNA chains using phosphoramidite coupling chemistry, allowing selection of the DNA sequence to either side, and specification of intermolecular DNA hybridization. In this way, we have developed a "toolbox" for construction of any stacking sequence of these semiconducting molecules. We have discovered that we need to use a full hierarchy of interactions: DNA guides the semiconductors into specified close proximity, hydrophobic-hydrophilic differentiation drives aggregation of the semiconductor moieties, and local geometry and electrostatic interactions define intermolecular positioning. As a result, the PDIs pack to give substantial intermolecular pi wave function overlap, leading to an evolution of singlet excited states from localized excitons in the PDI monomer to excimers with wave functions delocalized over all five PDIs in the pentamer. This is accompanied by a change in the dominant triplet forming mechanism from localized spin-orbit charge transfer mediated intersystem crossing for the monomer toward a delocalized excimer process for the pentamer. Our modular DNA-based assembly reveals real opportunities for the rapid development of bespoke semiconductor architectures with molecule-by-molecule precision. Title in Web of Science: Deoxyribonucleic Acid Encoded and Size-Defined pi-Stacking of Perylene Diimides

We describe a toolkit for Android smartphones and tablets that enables a user to access all the sensors available on the device. Data from individual sensors can be viewed as dynamic graphs. Output from one or more sensors can be recorded to a spreadsheet, with the sampling rate set by the learner. As a tool for inquiry learning, the sensors can be linked to ‘missions’ on the nQuire-it website, allowing learners to sample and share data for collaborative crowd-sourced investigations. \ud \ud Four nQuire-it missions have employed the sensor toolkit for investigating environmental noise, sunlight levels, air pressure and rainfall, and the speed of lifts (elevators). These four investigations represent a variety of methods to initiate, orchestrate and conclude inquiry science learning. Two of the missions are in the context of a study to develop a community of inquiry around weather and meteorology. The others are intended to engage members of the public in practical science activities. Analysis of the missions and the associated online discussions reveals that the Sense-it toolkit can be adopted for practical and engaging science investigations, though the issue of calibrating sensors on personal devices needs to be addressed.

Supplementary Schools in the UK offer educational opportunities for children and young people outside mainstream school provision. The paper reports an enquiry undertaken by practitioners in Greek Supplementary Schools in the UK to explore how features of mobile technologies may be leveraged to foster heritage language learning. It draws on the view that mobile learning can be a way for learners to explore the language informally and direct their own development (Kukulska-Hulme, 2015) and may also shape the learners’ ‘habits of mind’ (Wong, 2012, p.22) in learning—and consequently their language competencies. \ud \ud The project #ItsAllGreekToUS set to investigate how to create learning designs to incorporate effective use of mobile technologies within language learning and teaching. It draws on action research orientation and uses the idea of ‘Bring Your Own Device’ (BYOD) (JISC, 2013) in educational settings. The study involved several sessions around the concept of ‘loanwords’ and representations of this vocabulary in artefacts created with the use of mobile phones and a popular photography application (e.g. Pinterest).\ud \ud The participants were fourteen students (12-13s) attending a pre-GCSE class in a Greek School in London and nine students (12-14s) attending a GCSE class in a Greek School in Leicester.\ud \ud Evidence from user-generated content, the pupils’ views around the project and the practitioners’ observations are considered. The paper will discuss how students’ practices associated with mobile technologies are integrated into teachers’ practice. Particular attention will be drawn to designing language learning by blending traditional language classroom practices along incorporating the practices of sharing and curating content, as well as allowing ‘visibility’ through artefacts created by the learners.