2,776 research outputs found

    POIReviewQA: A Semantically Enriched POI Retrieval and Question Answering Dataset

    Full text link
    Many services that perform information retrieval for Points of Interest (POI) utilize a Lucene-based setup with spatial filtering. While this type of system is easy to implement it does not make use of semantics but relies on direct word matches between a query and reviews leading to a loss in both precision and recall. To study the challenging task of semantically enriching POIs from unstructured data in order to support open-domain search and question answering (QA), we introduce a new dataset POIReviewQA. It consists of 20k questions (e.g."is this restaurant dog friendly?") for 1022 Yelp business types. For each question we sampled 10 reviews, and annotated each sentence in the reviews whether it answers the question and what the corresponding answer is. To test a system's ability to understand the text we adopt an information retrieval evaluation by ranking all the review sentences for a question based on the likelihood that they answer this question. We build a Lucene-based baseline model, which achieves 77.0% AUC and 48.8% MAP. A sentence embedding-based model achieves 79.2% AUC and 41.8% MAP, indicating that the dataset presents a challenging problem for future research by the GIR community. The result technology can help exploit the thematic content of web documents and social media for characterisation of locations

    Location Cheating: A Security Challenge to Location-based Social Network Services

    Get PDF
    Location-based mobile social network services such as foursquare and Gowalla have grown exponentially over the past several years. These location-based services utilize the geographical position to enrich user experiences in a variety of contexts, including location-based searching and location-based mobile advertising. To attract more users, the location-based mobile social network services provide real-world rewards to the user, when a user checks in at a certain venue or location. This gives incentives for users to cheat on their locations. In this report, we investigate the threat of location cheating attacks, find the root cause of the vulnerability, and outline the possible defending mechanisms. We use foursquare as an example to introduce a novel location cheating attack, which can easily pass the current location verification mechanism (e.g., cheater code of foursquare). We also crawl the foursquare website. By analyzing the crawled data, we show that automated large scale cheating is possible. Through this work, we aim to call attention to location cheating in mobile social network services and provide insights into the defending mechanisms.Comment: 10 pages, 8 figures, accepted by the 31st International Conference on Distributed Computing Systems (ICDCS 2011

    Biomass distribution of different-aged needles in young and old Pinus cembra trees at highland and lowland sites

    Get PDF
    Conifer needles of different ages perform differently in ecophysiology. However, no study has investigated the biomass distribution of different-aged needles in a tree crown or/and a stand canopy. We carried out a study on young (∼50 years old) and old (∼200 years) Pinus cembra L. trees at highland (2100-2300ma.s.l.) and lowland (570m) sites in Switzerland. We found that both the young and the old trees living in the highlands had more needle biomass per tree than the same-aged trees of the same species living in the lowlands. This is mainly due to the greater longevity of needles in highland trees. It reflects the strategic responses of trees to low resource availability or high abiotic stress level. Having older needles increases the time that nutrients are resident in trees in less favorable environments, and compensates for shorter growing period in cold temperature

    Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography.

    Get PDF
    PurposeTo assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT).MethodsFifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty-degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias.ResultsICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771-0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95-3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04-3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12-1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (-0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers.ConclusionsBoth devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably

    Removal of epididymal visceral adipose tissue prevents obesity-induced multi-organ insulin resistance in male mice

    Get PDF
    Obesity is associated with insulin resistance, an important risk factor of type 2 diabetes, atherogenic dyslipidemia, and nonalcoholic fatty liver disease. The major purpose of this study was to test hypothesize that prophylactic removal of epididymal visceral adipose tissue (VAT) prevents obesity-induced multi-organ (liver, skeletal muscle, adipose tissue) insulin resistance. Accordingly, we surgically removed epididymal VAT pads from adult C57BL/6J mice and evaluated in vivo and cellular metabolic pathways involved in glucose and lipid metabolism following chronic high-fat diet (HFD) feeding. We found that VAT removal decreases HFD-induced body weight gain while increasing subcutaneous adipose tissue (SAT) mass. Strikingly, VAT removal prevents obesity-induced insulin resistance and hyperinsulinemia and markedly enhances insulin-stimulated AKT-phosphorylation at serine-473 (Ser473) and threonine-308 (Thr308) sites in SAT, liver, and skeletal muscle. VAT removal leads to decreases in plasma lipid concentrations and hepatic triglyceride (TG) content. In addition, VAT removal increases circulating adiponectin, a key insulin-sensitizing adipokine, whereas it decreases circulating interleukin 6, a pro-inflammatory adipokine. Consistent with these findings, VAT removal increases adenosine monophosphate-activated protein kinase C phosphorylation, a major downstream target of adiponectin signaling. Data obtained from RNA sequencing suggest that VAT removal prevents obesity-induced oxidative stress and inflammation in liver and SAT, respectively. Taken together, these findings highlight the metabolic benefits and possible action mechanisms of prophylactic VAT removal on obesity-induced insulin resistance and hepatosteatosis. Our results also provide important insight into understanding the extraordinary capability of adipose tissue to influence whole-body glucose and lipid metabolism as an active endocrine organ

    Morphological responses of root hairs to changes in soil and climate depend on plant life form

    Get PDF
    IntroductionRoot hairs increase the surface area of a plant’s root system that is in contact with the soil, thus facilitating plant water and nutrient uptake. However, little is known about the characteristics of the root hairs of herbaceous and woody plants and their specific response patterns to biotic and abiotic variables from the perspective of resource acquisition strategies in the context of global change.MethodsHere, we analyzed 74 published case studies with 1074 observations of root hair traits to identify patterns of root hair length, density and diameter in relation to soil (e.g., soil pH, nutrient levels), growing environments (e.g., greenhouse, field) and climatic factors (e.g., air temperature), as well as genome size and plant age.ResultsRoot hairs were longer, denser and thicker in woody plants compared with herbaceous plants, and the length and diameter of root hairs in herbaceous plants increased with genome size. With increasing plant age, woody plants had significantly longer and thicker root hairs, while root hair density and diameter declined significantly for herbaceous plants. Soil-cultured plants had longer root hairs than solution-cultured plants. The length and density of root hairs were greater in greenhouse-cultured plants than in field-grown plants, and the latter had thicker root hairs than the former. As soil pH increased, root hair length increased but diameter decreased in woody plants, while root hair density increased in herbaceous plants. Increased soil total nitrogen (N) and potassium (K) significantly increased root hair length, density and diameter in herbaceous plants, while soil total N significantly decreased root hair density in woody plants. Root hair length increased significantly, while root hair density decreased significantly, with higher mean annual temperature and greater precipitation seasonality, while the opposite pattern was true for a wider annual temperature range.DiscussionOur findings emphasize the life-form-specific responses of root hairs to soil and climatic variables. These findings will help deepen our understanding of resource acquisition strategies and their mechanisms in different plant forms under global climate change

    Taking account of asymptomatic infections: A modeling study of the COVID-19 outbreak on the Diamond Princess cruise ship

    Get PDF
    The COVID-19 outbreak on the Diamond Princess (DP) cruise ship has provided empirical data to study the transmission potential of COVID-19 with the presence of pre/asymptomatic cases. We studied the changes in R0 on DP from January 21 to February 19, 2020 based on chain binomial models under two scenarios: no quarantine assuming a random mixing condition, and quarantine of passengers in cabins-passengers may get infected either by an infectious case in a shared cabin or by pre/asymptomatic crew who continued to work. Estimates of R0 at the beginning of the epidemic were 3.27 (95% CI, 3.02-3.54) and 3.78 (95% CI, 3.49-4.09) respectively for serial intervals of 5 and 6 days; and when quarantine started, with the reported asymptomatic ratio 0.505, R0 rose to 4.18 (95%CI, 3.86-4.52) and 4.73 (95%CI, 4.37-5.12) respectively for passengers who might be exposed to the virus due to pre/asymptomatic crew. Results confirm that the higher the asymptomatic ratio is, the more infectious contacts would happen. We find evidence to support a US CDC report that a high proportion of asymptomatic infections could partially explain the high attack rate among cruise ship passengers and crew. Our study suggests that if the asymptomatic ratio is high, the conventional quarantine procedure may not be effective to stop the spread of virus

    Tree maps having chain movable fixed points

    Get PDF
    AbstractIn this paper we discuss some basic properties of chain reachable sets and chain equivalent sets of continuous maps. It is proved that if f:T→T is a tree map which has a chain movable fixed point v, and the chain equivalent set CE(v,f) is not contained in the set P(f) of periodic points of f, then there exists a positive integer p not greater than the number of points in the set End([CE(v,f)])−Pv(f) such that fp is turbulent, and the topological entropy h(f)⩾(log2)/p. This result generalizes the corresponding results given in Block and Coven (1986) [2], Guo et al. (2003) [6], Sun and Liu (2003) [10], Ye (2000) [11], Zhang and Zeng (2004) [12]. In addition, in this paper we also consider metric spaces which may not be trees but have open subsets U such that the closures U¯ are trees. Maps of such metric spaces which have chain movable fixed points are discussed
    • …
    corecore