Discovering Power Laws in Entity Length

This paper presents a discovery that the length of the entities in various datasets follows a family of scale-free power law distributions. The concept of entity here broadly includes the named entity, entity mention, time expression, aspect term, and domain-specific entity that are well investigated in natural language processing and related areas. The entity length denotes the number of words in an entity. The power law distributions in entity length possess the scale-free property and have well-defined means and finite variances. We explain the phenomenon of power laws in entity length by the principle of least effort in communication and the preferential mechanism

Historical suitability and sustainability of sicani mountains landscape (western Sicily): An integrated approach of phytosociology and archaeobotany

Since 2015, the ongoing project "Harvesting Memories" has been focused on long-term landscape dynamics in Sicani Mountains (Western Sicily). Archaeological excavations in the case study site of Contrada Castro (Corleone) have investigated a settlement which was mainly occupied during the Early Middle Ages (late 8th-11th century AD). This paper aims to understand the historical suitability and sustainability of this area analysing the correlation between the current dynamics of plant communities and the historical use of woods detected by the archaeobotanical record. An integrated approach between phytosociology and archaeobotany has been applied. The vegetation series of the study area has been used as a model to understand the ecological meaning and spatial distribution of archaeobotanical data on charcoals from the Medieval layers of the Contrada Castro site. The intersection between the frequency data of the archaeobotanical record and the phytosociological analysis have confirmed the maintenance of the same plant communities during the last millennium due to the sustainable exploitation of wood resources. An integrated comparison between the structure and composition of current phytocoenoses with archaeobotanical data allowed us to confirm that this landscape is High Nature Value (HNV) farmland and to interpret the historical vegetation dynamics linked to the activities and economy of a rural community

Arabis madonia (Brassicaceae), specie critica della flora siciliana

Nell’ambito di ricerche biosistematiche condotte sulla flora endemica della Sicilia, viene esaminata sotto il profilo morfologico Arabis madonia C.Presl, una specie ancora poco nota e critica sotto il profilo tassonomico

Diagnosis and treatment of thoracic aortic intramural hematoma

AbstractPurpose: This report reviews our recent experience with nine patients who had intramural hematoma of the thoracic aorta.Methods: This was a retrospective study of all patients who had intramural hematoma at our institution from 1989 to 1994. Patients who had identifiable intimal flap, tear, or penetrating aortic ulcer were excluded from the study.Results: Among these nine elderly patients (mean age, 76 years), the most common presentation was chest or back pain. Intramural hematoma was diagnosed by a variety of high-resolution imaging techniques. The descending thoracic aorta alone was involved in seven patients, whereas the ascending aorta was affected in the other two patients. One patient had evidence of an aneurysm (5.0 cm diameter) in the region of the hematoma. All patients were initially managed nonsurgically with blood pressure control. Both patients who had ascending aortic involvement had progression of aortic hematoma, which resulted in death in one case and in successful surgery in the other. Six of the seven patients who had descending aortic involvement alone were successfully managed without aortic surgery. The patient who had intramural hematoma and associated aortic aneurysm, however, had severe, recurrent pain and underwent successful aortic replacement. Another patient had recurrent pain associated with hypertension, but was successfully managed nonsurgically with antihypertensive therapy. All eight survivors are doing well at a median follow-up of 19 months.Conclusions: Intramural hematoma appears to be a distinct entity, although overlap with aortic dissection or penetrating aortic ulcer exists. Aggressive control of blood pressure with intensive care unit monitoring has been our initial management. Patients who have involvement of the descending thoracic aorta alone can frequently be managed without surgery in the absence of coexisting aneurysmal dilatation or disease progression. Our experience suggests that a more aggressive approach with early surgery is warranted in patients who have ascending aortic involvement or those who have coexisting aneurysm and intramural hematoma. (J Vasc Surg 1996;24;1022-9.

A study on text-score disagreement in online reviews

In this paper, we focus on online reviews and employ artificial intelligence tools, taken from the cognitive computing field, to help understanding the relationships between the textual part of the review and the assigned numerical score. We move from the intuitions that 1) a set of textual reviews expressing different sentiments may feature the same score (and vice-versa); and 2) detecting and analyzing the mismatches between the review content and the actual score may benefit both service providers and consumers, by highlighting specific factors of satisfaction (and dissatisfaction) in texts. To prove the intuitions, we adopt sentiment analysis techniques and we concentrate on hotel reviews, to find polarity mismatches therein. In particular, we first train a text classifier with a set of annotated hotel reviews, taken from the Booking website. Then, we analyze a large dataset, with around 160k hotel reviews collected from Tripadvisor, with the aim of detecting a polarity mismatch, indicating if the textual content of the review is in line, or not, with the associated score. Using well established artificial intelligence techniques and analyzing in depth the reviews featuring a mismatch between the text polarity and the score, we find that -on a scale of five stars- those reviews ranked with middle scores include a mixture of positive and negative aspects. The approach proposed here, beside acting as a polarity detector, provides an effective selection of reviews -on an initial very large dataset- that may allow both consumers and providers to focus directly on the review subset featuring a text/score disagreement, which conveniently convey to the user a summary of positive and negative features of the review target.Comment: This is the accepted version of the paper. The final version will be published in the Journal of Cognitive Computation, available at Springer via http://dx.doi.org/10.1007/s12559-017-9496-

The Chemorepellent, Netrin-1, Appears to Signal Through a Tyrosine Kinase in Tetrahymena thermophila

Netrin-1 is a pleiotropic peptide signaling molecule. Its most well-known role in vertebrate development is neuronal guidance. Depending upon the cell type and signal concentration gradient, netrin-1 may serve either as a chemoattractant, causing formation of axonal growth cones, or as a chemorepellent, causing growth cone collapse within the axon. Netrin-1 can bind to at least two types of receptors, and uses a variety of signaling proteins to convey its message. In some vertebrate cell types, the netrin-1 signal is G-protein mediated, while in other cell types, netrin signaling requires a tyrosine kinase or some other combination of kinases in order to signal. Tetrahymena thermophila are free-living, eukaryotic cells that can respond to chemoattractants and chemorepellents by moving toward attractants and away from repellents. By studying the behavior of these organisms, we have found that netrin-1 acts as a chemorepellent in T. thermophila. Response to netrin-1 is concentration dependent, with an EC100 of approximately 1 micromolar, and an EC50 of approximately 10 pM. Netrin-1 avoidance may be effectively eliminated by the addition of the broad-spectrum tyrosine kinase inhibitor, genistein, to the behavioral assay. The IC100 of genistein was approximately 75 micrograms/ml, while the IC50 of this compound was near 50 micrograms/ml. G-protein inhibitors, calcium chelators, and a number of other pharmacological inhibitors had no effect on netrin-1 signaling in this organism. These data show that netrin-1 is a chemorepellent in Tetrahymena thermophila and that netrin signaling appears to implicate a tyrosine kinase in this organism. Further studies will help us to determine whether genistein is specifically acting upon a tyrosine kinase pathway or whether the inhibition is occurring via some other genistein-mediated effect

Intraoperative determinants of infrainguinal bypass graft patency: A prospective study

Objectives:To evaluate a number of currently available methods for intraoperative assessment of infrainguinal bypass grafts (IBG) in terms of detecting technical errors and predicting graft failure.Design:Prospective open clinical study.Methods:Forty-nine patients undergoing 54 consecutive IBG were studied. Intraoperatively, the following measurements were performed: distal pulse palpation (DPP), continuous wave Doppler (CWD), pulse volume recording (PVR), and ultrasonic volume flowmetry (UVF), followed by intraoperative angiography of the entire graft and runoff vessels. The outflow resistance was graded according to the guidelines of the Society for Vascular Surgery and International Society for Cardiovascular Surgery (SVS/ISCVS runoff score). Graft patency was determined noninvasively (PVR, colour Duplex) up to 12 months following surgery. Predictive values and likelihood ratios for the intraoperative tests in detecting a technical problem during the bypass procedure and in predicting early graft failure were calculated.Results:There were five immediate revisions for problems detected intraoperatively. Angiography did not identify any additional problems but assisted in the correct location of the problems detected by the other tests. DPP and CWD were highly significant indicators of the need for revision with likelihood ratios for a positive test of 14.7 (p < 0.01) and 12.3 (p < 0.01) respectively. PVR did not achieve statistical significance in this respect. None of the intraoperative tests was a statistically significant predictor of early graft failure. The SVS/ISCVS runoff score, on the other hand, predicted early failure with a PPV of 33% (likelihood ratio for a positive test of 4.9, p < 0.05). None of the grafts with a perfect SVS/ISCVS runoff score (n = 39) failed in the first postoperative month.Conclusions:Simple CWD insonation of graft and anastomoses is the best intraoperative indicator for technical inadequacies after IBG. Routine intraoperative angiography is not necessary and intraoperative anatomical imaging may be reserved for situations in which noninvasive documentation of technical success is absent. Contrary to the intraoperative haemodynamic test results, the SVS/ISCVS runoff score is a good predictor of early graft failure