From Key Points to Key Point Hierarchy: Structured and Expressive Opinion Summarization

Key Point Analysis (KPA) has been recently proposed for deriving fine-grained insights from collections of textual comments. KPA extracts the main points in the data as a list of concise sentences or phrases, termed key points, and quantifies their prevalence. While key points are more expressive than word clouds and key phrases, making sense of a long, flat list of key points, which often express related ideas in varying levels of granularity, may still be challenging. To address this limitation of KPA, we introduce the task of organizing a given set of key points into a hierarchy, according to their specificity. Such hierarchies may be viewed as a novel type of Textual Entailment Graph. We develop ThinkP, a high quality benchmark dataset of key point hierarchies for business and product reviews, obtained by consolidating multiple annotations. We compare different methods for predicting pairwise relations between key points, and for inferring a hierarchy from these pairwise predictions. In particular, for the task of computing pairwise key point relations, we achieve significant gains over existing strong baselines by applying directional distributional similarity methods to a novel distributional representation of key points, and further boost performance via weak supervision.Comment: ACL 202

CHAMP: Efficient Annotation and Consolidation of Cluster Hierarchies

Various NLP tasks require a complex hierarchical structure over nodes, where each node is a cluster of items. Examples include generating entailment graphs, hierarchical cross-document coreference resolution, annotating event and subevent relations, etc. To enable efficient annotation of such hierarchical structures, we release CHAMP, an open source tool allowing to incrementally construct both clusters and hierarchy simultaneously over any type of texts. This incremental approach significantly reduces annotation time compared to the common pairwise annotation approach and also guarantees maintaining transitivity at the cluster and hierarchy levels. Furthermore, CHAMP includes a consolidation mode, where an adjudicator can easily compare multiple cluster hierarchy annotations and resolve disagreements.Comment: EMNLP 202

Job stress, cigarette smoking and cessation: The conditioning effects of peer support

Relationships between questionnaire measures of job stress and smoking intensity (SI) and cessation were studied among 560 disease-free smoking males and 310 quitters all members of 22 kibbutzim. The main-effect hypothesis that stress is positively related to SI and negatively to cessation received some support in correlational and multiple regression analyses for the entire sample. Hours of work, work addiction, lack of influence, intrinsic impoverishment and lack support were positively associated with SI. Conflict, responsibility, hours of work, low status, lack of influence and harsh working conditions were negatively associated with cessation. When peer support was dichotomized into low and high, we found that persons reporting low support smoked significantly more than those who reported high support. Seeking effects of both hours of work and support on SI, we found additive main effects but no interaction effect. The average number of cigarettes smoked by people who worked less than 8 hours and reported high support was 17, whereas people who worked more than 8 hours and reported low support smoked an average of 22 cigarettes a day. The buffering effect of support on the relationship between stress and both SI and cessation of smoking was examined by means of interaction analysis. No buffer effect was evident for SI. However, for respondents reporting low support more job stressors were negatively related to cessation than among those reporting high support, confirming the support-buffer hypothesis that social support may be measurement of support are discussed. We conclude with the hypothesis that social support may be detrimental to the smoker, depending on the smoking attitudes and behaviors of the 'supportive' others.

Outcomes of Extracorporeal Membrane Oxygenation (ECMO) for COVID-19 Patients: A Multi-Institutional Analysis

Background: In March 2020, COVID-19 was announced as a global pandemic. The first COVID-19 patient was connected to an ECMO device in Israel during that time. Since then, over 200 patients have required ECMO support due to COVID-19 infection. The present study is a multi-institutional analysis of all COVID-19 patients requiring veno-venous (VV) ECMO in Israel. The aim was to characterize and compare the survivors and deceased patients as well as establish risk factors for mortality. Methods: This retrospective multi-institutional study was conducted from March 2020 to March 2021 in eleven of twelve ECMO centers operating in Israel. All COVID-19 patients on VV ECMO support were included in the cohort. The patients were analyzed based on their comorbidities, procedural data, adverse event on ECMO, and outcomes. Univariate and multivariate analyses were used to compare the deceased and the surviving patients. Results: The study included 197 patients, of which 150 (76%) were males, and the mean age was 50.7 ± 12 years. Overall mortality was 106 (54%). Compared with the deceased subjects, survivors were significantly younger (48 ± 11 vs. 53 ± 12 years), suffered less from ischemic heart disease (IHD) (3% vs. 12%), and were ventilated for a significantly shorter period (≤4 days) prior to cannulation (77% vs. 63%). Patients in the deceased group experienced more kidney failure and sepsis. Rates of other complications were comparable between groups. Conclusions: Based on this study, we conclude that early cannulation (≤4 days) of younger patients (≤55 years) may improve overall survival and that a history of IHD might indicate a reduced prognosis

Genome-wide transcription survey on flavour production in Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is widely used as aroma producer in the preparation of fermented foods and beverages. During food fermentations, secondary metabolites like 3-methyl-1-butanol, 4-methyl-2-oxopentanoate, 3-methyl-2-oxobutanoate and 3-methylbutyrate emerge. These four compounds have a major influence on the final taste of fermented foods. Their presence is influenced by the availability of free branched chained amino acids (BCAA). To study the underlying molecular mechanism of the formation of these compounds, we performed genome-wide transcription analyses with cDNA microarrays. The expression profile of yeast during flavour formation, when cultivated on L-leucine, was compared to the expression profile of cells cultivated on ammonia. In addition, the expression profiles of cells cultivated in a batch culture were compared to cells cultivated under continuous growth conditions. Genome-wide gene analysis of these samples revealed a group of 117 genes, which w! ere more than two-fold up- or down-regulated and significantly altered in gene expression (P < 0.001) under both cultivation conditions. This group included genes encoding enzymes of different amino acid metabolism pathways. The group of the BCAA metabolism was not significantly altered in gene expression. Genes identified with altered expression levels, in only batch or continuous culture fermentions, represented functional groups concerning energy, protein fate, cell cycle and DNA processing. Furthermore, clustering of genome-wide data revealed that the type of cultivation overruled the differences in N-source in the gene-expression profiles. This observation emphasizes the importance of sample history in gene expression analysis.

Rapid identification of target genes for 3-methyl-1-butanol production in Saccharomyces cerevisiae

Extracellular conditions determine the taste of fermented foods by affecting metabolite formation by the micro-organisms involved. To identify targets for improvement of metabolite formation in food fermentation processes, automated high-throughput screening and cDNA microarray approaches were applied. Saccharomyces cerevisiae was cultivated in 96-well microtiter plates, and the effects of salt concentration and pH on the growth and synthesis of the fusel alcohol-flavoured substance, 3-methyl-1-butanol, was evaluated. Optimal fermentation conditions for 3-methyl-1-butanol concentration were found at pH 3.0 and 0% NaCl. To identify genes encoding enzymes with major influence on product formation, a genome-wide gene expression analysis was carried out with S. cerevisiae cells grown at pH 3.0 (optimal for 3-methyl-1-butanol formation) and pH 5.0 (yeast cultivated under standard conditions). A subset of 747 genes was significantly induced or repressed when the pH was changed from pH 5.0 to 3.0. Expression of seven genes related to the 3-methyl-1-butanol pathway, i.e. LAT1, PDX1, THI3, ALD4, ILV3, ILV5 and LEU4, strongly changed in response to this switch in pH of the growth medium. In addition, genes involved in NAD metabolism, i.e. BNA2, BNA3, BNA4 and BNA6, or those involved in the TCA cycle and glutamate metabolism, i.e. MEU1, CIT1, CIT2, KDG1 and KDG2, displayed significant changes in expression. The results indicate that this is a rapid and valuable approach for identification of interesting target genes for improvement of yeast strains used in industrial processes.