bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delimited control and computational effects
Authors: DOWNEN PAUL , ARIOLA ZENA M. 
Published: January 2014

AbstractWe give a framework for delimited control with multiple prompts, in the style of Parigot's λμ-calculus, through a series of incremental extensions by starting with the pure λ-calculus. Each language inherits the semantics and reduction theory of its parent, giving a systematic way to describe each level of control. For each language of interest, we fully characterize its semantics in terms of a reduction semantics, operational semantics, continuation-passing style transform, and abstract machine. Furthermore, the control operations are expressed in terms of fine-grained primitives that can be used to build well-known, higher-level control operators. In order to illustrate the expressive power provided by various languages, we show how other computational effects can be encoded in terms of these control operators.
On the Importance Sampling of Self-Avoiding Walks
Authors: BOUSQUET-MÉLOU MIREILLE 
Published: January 2014

In a 1976 paper published in Science, Knuth presented an algorithm to sample (non-uniform) self-avoiding walks crossing a square of side k. From this sample, he constructed an estimator for the number of such walks. The quality of this estimator is directly related to the (relative) variance of a certain random variable Xk. From his experiments, Knuth suspected that this variance was extremely large (so that the estimator would not be very efficient). But how large? For the analogous Rosenbluth algorithm, which samples unconfined self-avoiding walks of length n, the variance of the corresponding estimator is believed to be exponential in n.A few years ago, Bassetti and Diaconis showed that, for a sampler à la Knuth that generates walks crossing a k × k square and consisting of North and East steps, the relative variance is only $O(\sqrt k)$. In this note we take one step further and show that, for walks consisting of North, South and East steps, the relative variance jumps to $2^{k(k+1)}/(k+1)^{2k}$. This is exponential in the average length of the walks, which is of order k2. We also obtain partial results for general self-avoiding walks crossing a square, suggesting that the relative variance could be exponential in k2 (which is again the average length of these walks).Knuth's algorithm is a basic example of a widely used technique called sequential importance sampling. The present paper, following the paper by Bassetti and Diaconis, is one of very few examples where the variance of the estimator can be found.
Characteristics of Hospitals Diverting Ambulances in a California EMS System
Authors: Kahn Christopher A. , Stratton Samuel J. , Anderson Craig L. 
Published: January 2014

AbstractIntroductionWhile several reports discuss controversies regarding ambulance diversion from acute care hospitals and the mortality, financial, and resource effects, there is scant literature related to the effect of hospital characteristics.Hypothesis/ProblemThe objective of this study was to describe specific paramedic receiving center characteristics that are associated with ambulance diversion rates in an Emergency Medical Services system.MethodsA retrospective observational study design was used. The study was performed in a suburban EMS system with 27 paramedic receiving centers studied; one additional hospital present at the beginning of the study period (2000-2008) was excluded due to lack of recent data. Hospital-level and population-level characteristics were gathered, including diversion rate (hours on diversion/total hours open), for-profit status, number of specialty services (including trauma, burn, cardiovascular surgery, renal transplant services, cardiac catheterization capability [both interventional and diagnostic], and burn surgery), average inpatient bed occupancy rate (total patient days/licensed bed days), annual emergency department (ED) volume (patients per year), ED admission rate (percent of ED patients admitted), and percent of patients leaving without being seen. Demographic characteristics included percent of persons in each hospital's immediate census tract below the 100% and 200% poverty lines (each considered separately), and population density within the census tract. Bivariate and regression analyses were performed.ResultsDiversion rates for the 27 centers ranged from 0.3%-14.5% (median 4.5%). Average inpatient bed occupancy rate and presence of specialty services were correlated with an increase in diversion rate; occupancy rate showed a 0.08% increase in diversion hours per 1% increase in occupancy rate (95% CI, 0.01%-0.16%), and hospitals with specialty services had, on average, a 4.1% higher diversion rate than other hospitals (95% CI, 1.6%-6.7%). Other characteristics did not show a statistically significant effect. When a regression was performed, only the presence of specialty services was related to the ambulance diversion rate.ConclusionsHospitals in this study providing specialty services were more likely to have higher diversion rates. This may result in increased difficulty getting patients requiring specialty care to centers able to provide the needed level of service. Major limitations include the retrospective nature of the study, as well as reliance on multiple data systems.KahnC,StrattonS,AndersonC.Characteristics of hospitals diverting ambulances in a California EMS system.Prehosp Disaster Med.2014;29(1):1-5.
Reduction in STEMI Transfer Times Utilizing a Municipal “911” Ambulance Service
Authors: Tennyson Joseph C. , Quale Mark R. 
Published: January 2014

AbstractIntroductionThe time interval from diagnosis to reperfusion therapy for patients experiencing ST-segment elevation myocardial infarction (STEMI) has a significant impact on morbidity and mortality.HypothesisIt is hypothesized that the time required for interfacility patient transfers from a community hospital to a regional percutaneous coronary intervention (PCI) center using an Advanced Life Support (ALS) transfer ambulance service is no different than utilizing the “911” ALS ambulance.MethodsQuality assurance data collected by a tertiary care center cardiac catheterization program were reviewed retrospectively. Data were collected on all patients with STEMI requiring interfacility transfer from a local community hospital to the tertiary care center's PCI suite, approximately 16 miles away by ground, 12 miles by air. In 2009, transfers of patients with STEMI were redirected to the municipal ALS ambulance service, instead of the hospital's contracted ALS transfer service. Data were collected from January 2007 through May 2013. Temporal data were compared between transports initiated through the contracted ALS ambulance service and the municipal ALS service. Data points included time of initial transport request and time of ambulance arrival to the sending facility and the receiving PCI suite.ResultsDuring the 4-year study period, 63 patients diagnosed with STEMI and transferred to the receiving hospital's PCI suite were included in this study. Mean times from the transport request to arrival of the ambulance at the sending hospital's emergency department were six minutes (95% CI, 4-7 minutes) via municipal ALS and 13 minutes (95% CI, 9-16 minutes) for the ALS transfer service. The mean times from the ground transport request to arrival at the receiving hospital's PCI suite when utilizing the municipal ALS ambulance and hospital contracted ALS ambulance services were 48 minutes (95% CI, 33-64 minutes) and 56 minutes (95% CI 52-59 minutes), respectively. This eight-minute period represented a 14% (P = .001) reduction in the mean transfer time to the PCI suite for patients transported via the municipal ALS ambulance.ConclusionIn the appropriate setting, the use of the municipal “911” ALS ambulance service for the interfacility transport of patients with STEMI appears advantageous in reducing door-to-catheterization times.TennysonJC, QualeMR. Reduction in STEMI transfer times utilizing a municipal “911” ambulance service. Prehosp Disaster Med. 2014;29(1):1-4.
Innovation in urban agricultural practices: Responding to diverse production environments
Authors: Pfeiffer Anne , Silva Erin , Colquhoun Jed 
Published: January 2014

AbstractAlthough discussion of the role of urban agriculture in developing nations has occurred over the past decade, dialogue relating to urban agriculture in industrialized countries, including the United States (US) has only recently begun to attract significant attention. The unique factors that influence urban agriculture, including limited and non-traditional land access, use of reclaimed soils and alternative growing mediums, local legal and political environments, social and community-based missions, and involvement of non-traditional farmers, create a production system distinct from rural agricultural enterprises. In many cases, specific local environmental and external factors drive urban farms to develop unique innovations for space-intensive production systems, often creating a dominant paradigm for urban farming for a given location. Furthermore, non-production-related organizational goals are often the primary focus of urban agricultural operations, with the food production becoming a secondary objective. In order to address this information gap regarding the status of urban agriculture in the US, our project, centered at the University of Wisconsin-Madison, gathered data through site visits to and interviews of organizations in seven cities, examining how structural and strategic food system factors shape urban agricultural efforts. A broad range of operations are considered, including diverse business and production models based on both commercial and community-based management strategies and production in parking and vacant lots, warehouses, public land and peri-urban locations. Based on these observations, the unique innovations in space-intensive agricultural production that have arisen in response to urban food system factors are discussed. We conclude with an assessment of the most significant challenges continuing to face urban agriculture.
The Pharmacokinetics and Pharmacokinetic/Pharmacodynamic Relationships of Evacetrapib Administered as Monotherapy or in Combination With Statins
Authors: Friedrich S , Kastelein JJP , James D , Waterhouse T , Nissen SE , Nicholls SJ , Krueger KA 
Published: January 2014

Evacetrapib is a novel cholesteryl ester transfer protein (CETP) inhibitor currently being evaluated in a late‐stage cardiovascular outcome trial. Using population‐based models, we analyzed evacetrapib concentration data along with high‐density lipoprotein cholesterol (HDL‐C) and low‐density lipoprotein cholesterol (LDL‐C) data from a 12‐week study in dyslipidemic patients treated with evacetrapib alone or in combination with atorvastatin, simvastatin, or rosuvastatin. Evacetrapib pharmacokinetics were characterized using a two‐compartment model with first‐order absorption. Evacetrapib exposure increased in a less than dose‐proportional manner, similar to other CETP inhibitors. No patient factors had a clinically relevant impact on evacetrapib pharmacokinetics. The relationships between evacetrapib exposure and HDL‐C and LDL‐C were characterized using Emax models. The theoretical maximal mean HDL‐C increase and LDL‐C decrease relative to baseline were 177 and 44.1%, respectively. HDL‐C change from baseline was found to be negatively correlated with baseline HDL‐C. A pharmacologically independent LDL‐C reduction was found when evacetrapib was coadministered with statins.CPT Pharmacometrics Syst. Pharmacol. (2014) 3, e94; doi:10.1038/psp.2013.70; published online 22 January 2014
Spinning up the polymorphs of calcium carbonate
Authors: Boulos Ramiz A. , Zhang Fei , Tjandra Edwin S. , Martin Adam D. , Spagnoli Dino , Raston Colin L. 
Published: January 2014

AbstractControlling the growth of the polymorphs of calcium carbonate is important in understanding the changing environmental conditions in the oceans. Aragonite is the main polymorph in the inner shells of marine organisms and can be readily converted to calcite, which is the most stable polymorph of calcium carbonate. Both of these polymorphs are significantly more stable than vaterite, which is the other naturally occurring polymorph of calcium carbonate and this is reflected in its limited distribution in nature. We have investigated the effect of high shear forces on the phase behaviour of calcium carbonate using a vortex fluidic device (VFD), with experimental parameters varied to explore calcium carbonate mineralisation. Variation of tilt angle, rotation speed and temperature allow for control over the size, shape and phase of the resulting calcium carbonate.
Gold nanoparticle assemblies stabilized by bis(phthalocyaninato)lanthanide(III) complexes through van der Waals interactions
Authors: Noda Yuki , Noro Shin-ichiro , Akutagawa Tomoyuki , Nakamura Takayoshi 
Published: January 2014

AbstractGold nanoparticle assemblies possess diverse application potential, ranging from industrial nanotechnology to medical biotechnology. Because the structures and properties of assemblies are directly affected by the stabilization mechanism between the organic molecules serving as protecting ligands and the gold nanoparticle surface, it is crucial to find and investigate new stabilization mechanisms. Here, we report that π-conjugated phthalocyanine rings can serve as stabilizing ligands for gold nanoparticles. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato)terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. AC magnetic measurements and the electron-transport properties of the assemblies give direct evidence that the phthalocyanines are isolated from each other. Each nanoparticle shows weak electronic coupling despite the short internanoparticle distance (~1 nm), suggesting Efros–Shklovskii-type variable-range hopping and collective single-electron tunnelling behaviours.
Processing of microRNA primary transcripts requires heme in mammalian cells
Authors: Weitz Sara H. , Gong Ming , Barr Ian , Weiss Shimon , Guo Feng 
Published: January 2014

Significance
MicroRNAs (miRNAs) have important functions in development and cell physiology. The vast majority of mature miRNAs are produced from primary transcripts of microRNAs (pri-miRNAs) by a multi-step pathway. The first step, cleavage of pri-miRNAs by the Microprocessor complex, is highly regulated but technically challenging to study. We have developed a robust method that faithfully measures pri-miRNA processing efficiency in live cells. Using this assay, we establish an essential function of heme in miRNA maturation, a provocative idea suggested by previous biochemical studies. Our study reveals a previously unknown cellular function of this central biological cofactor, linking metal ion biology with the regulation of noncoding RNAs. Our method should be widely useful for studying RNA processing in biology and diseases.
Tactile perception and working memory in rats and humans
Authors: Fassihi Arash , Akrami Athena , Esmaeili Vahid , Diamond Mathew E. 
Published: January 2014

Significance
Many higher cognitive functions involve working memory (WM), the storage and manipulation of information across limited time intervals. Comparing the WM capacity of different species is a key step toward understanding the underlying brain mechanisms. This study uncovers previously unknown sensory WM abilities in rats. They received two vibratory stimuli on their whiskers, separated by a variable delay, and had to compare vibration features. In analogous experiments, human subjects compared two stimuli applied to the fingertip. The acuity shown by rats in judging stimulus differences and their WM proficiency (across delays of 8 s, the longest tested) overlapped those of humans. Sensory WM now joins other cognitive functions within the rodent repertoire, setting the stage for exploration of its neuronal coding.
In vitro analysis suggests that difference in cell movement during direct interaction can generate various pigment patterns in vivo
Authors: Yamanaka Hiroaki , Kondo Shigeru 
Published: January 2014

Significance
The periodic pigment patterns of organisms, such as spots and stripes, have suggested the presence of a mathematical system generating the patterns. The most famous one is the reaction–diffusion system. Although the system explains the pattern formation well, the biological substances corresponding to the diffusive factors in the system have not been elucidated. Here, we observed the behavior of zebrafish pigment cells in vitro and found that WT cells showed run-and-chase movement in the direct interaction, whereas the pattern mutant cells showed different cell movement. These results suggested that gene mutations affect the reaction–diffusion system by changing the cell movement, which corresponds to the interaction of diffusive factors in the reaction–diffusion system.
Conformal piezoelectric energy harvesting and storage from motions of the heart, lung, and diaphragm
Authors: Dagdeviren Canan , Yang Byung Duk , Su Yewang , Tran Phat L. , Joe Pauline , Anderson Eric , Xia Jing , Doraiswamy Vijay , Dehdashti Behrooz , Feng Xue , Lu Bingwei , Poston Robert , Khalpey Zain , Ghaffari Roozbeh , Huang Yonggang , Slepian Marvin J. , Rogers John A. 
Published: January 2014

Significance
Heart rate monitors, pacemakers, cardioverter-defibrillators, and neural stimulators constitute broad classes of electronic implants that rely on battery power for operation. Means for harvesting power directly from natural processes of the body represent attractive alternatives for these and future types of biomedical devices. Here we demonstrate a complete, flexible, and integrated system that is capable of harvesting and storing energy from the natural contractile and relaxation motions of the heart, lung, and diaphragm at levels that meet requirements for practical applications. Systematic experimental evaluations in large animal models and quantitatively accurate computational models reveal the fundamental modes of operation and establish routes for further improvements.
Empirical prediction of genomic susceptibilities for multiple cancer classes
Authors: Kim Minseung , Kim Sung-Hou 
Published: January 2014

Significance
It is widely assumed that human genomic variations are associated with an individual’s susceptibility to complex diseases such as cancers and autoimmune diseases. However, extensive genome-wide association studies thus far had limited success because the results have low predictive value of practical utility to individuals. We present a prediction process where two machine-learning analysis methods are applied to two different descriptors of each individual’s common genomic variations to predict an individual’s susceptibility to eight major cancer traits. The accuracy of the prediction ranges from 33% to 57% depending on cancer type, which is significantly better than 11% for a random prediction, with probability estimates that may be useful for making practical health decisions for individuals or for a population.
Functional map of arrestin-1 at single amino acid resolution
Authors: Ostermaier Martin K. , Peterhans Christian , Jaussi Rolf , Deupi Xavier , Standfuss Jörg 
Published: January 2014

Significance
G protein-coupled receptors (GPCRs) comprise 2–3% of human proteins and are key for cellular communication in higher organisms. Thus, these receptors are essential in cell physiology, and their malfunction is commonly translated into pathological outcomes. Our structural knowledge of GPCRs has improved dramatically in recent years. The next big leap is deciphering the structure and function of their complexes with signaling proteins, and, specifically, the mechanisms by which these complexes form and activate. Our unbiased and complete scanning mutagenesis provides compelling functional insights into how a phosphorylated GPCR is desensitized by binding of arrestin. Combination of the discovered mutations will allow engineering of arrestins with either increased or reduced binding affinity with a broad range of applications in research, diagnostics, and pharmacology.
Structural basis for nuclear import of splicing factors by human Transportin 3
Authors: Maertens Goedele N. , Cook Nicola J. , Wang Weifeng , Hare Stephen , Gupta Saumya Shree , Öztop Ilker , Lee KyeongEun , Pye Valerie E. , Cosnefroy Ophélie , Snijders Ambrosius P. , KewalRamani Vineet N. , Fassati Ariberto , Engelman Alan , Cherepanov Peter 
Published: January 2014

Significance
Transportin 3 (Tnpo3) was shown to orchestrate nuclear import of splicing factors over a decade ago, but how it recognizes these cargoes remained unknown. Furthermore, the recently discovered role for Tnpo3 as a cofactor of HIV-1 replication requires mechanistic clarification. We show that Tnpo3 associates with a wide range of proteins involved in mRNA metabolism, the majority of which contain serine/arginine-rich domains. Using X-ray crystallography we determined the three-dimensional structures of Tnpo3 in its key functional states, explaining how this nuclear import factor binds and releases its cargoes. We also show that Tnpo3 mutants that are not able to interact with cleavage and polyadenylation specificity factor 6 do not facilitate HIV-1 infectivity, suggesting a potential route of pharmacological intervention in the treatment of AIDS.
Membrane adhesion dictates Golgi stacking and cisternal morphology
Authors: Lee Intaek , Tiwari Neeraj , Dunlop Myun Hwa , Graham Morven , Liu Xinran , Rothman James E. 
Published: January 2014

Significance
Stacking of cisternae in the mammalian Golgi apparatus is known to be a highly complicated process that involves a large number of adhesive proteins, including Golgi reassembly and stacking proteins (GRASPs) and Golgin tethers, as well as coordinated disassembly/reassembly of Golgi stacks during mitotic cell division. Using extensive quantitative analysis of electron microscopic data, we show here that Golgi stacking with flattened cisternae is maintained in HeLa cells depleted of GRASP65/55 proteins when the GRASP-deficient cells are complemented by exogenous expression of either Golgi matrix protein of 130 kDa or Golgin45. These results strongly suggest that the Golgi stack assembly and cisternal morphology are governed by simple membrane adhesion at the core, explaining how Golgi stacking occurs in organisms, which do not express (or use) GRASP-type adhesion proteins such as plants and yeast.