Data and performance profiles applying an adaptive truncation criterion, within linesearch-based truncated Newton methods, in large scale nonconvex optimization.

In this paper, we report data and experiments related to the research article entitled "An adaptive truncation criterion, for linesearch-based truncated Newton methods in large scale nonconvex optimization" by Caliciotti et al. [1]. In particular, in Caliciotti et al. [1], large scale unconstrained optimization problems are considered by applying linesearch-based truncated Newton methods. In this framework, a key point is the reduction of the number of inner iterations needed, at each outer iteration, to approximately solving the Newton equation. A novel adaptive truncation criterion is introduced in Caliciotti et al. [1] to this aim. Here, we report the details concerning numerical experiences over a commonly used test set, namely CUTEst (Gould et al., 2015) [2]. Moreover, comparisons are reported in terms of performance profiles (Dolan and Moré, 2002) [3], adopting different parameters settings. Finally, our linesearch-based scheme is compared with a renowned trust region method, namely TRON (Lin and Moré, 1999) [4].

Ram-pressure feeding of supermassive black holes.

When a supermassive black hole at the centre of a galaxy accretes matter, it gives rise to a highly energetic phenomenon: an active galactic nucleus. Numerous physical processes have been proposed to account for the funnelling of gas towards the galactic centre to feed the black hole. There are also several physical processes that can remove gas from a galaxy, one of which is ram-pressure stripping by the hot gas that fills the space between galaxies in galaxy clusters. Here we report that six out of a sample of seven 'jellyfish' galaxies-galaxies with long 'tentacles' of material that extend for dozens of kiloparsecs beyond the galactic disks-host an active nucleus, and two of them also have galactic-scale ionization cones. The high incidence of nuclear activity among heavily stripped jellyfish galaxies may be due to ram pressure causing gas to flow towards the centre and triggering the activity, or to an enhancement of the stripping caused by energy injection from the active nucleus, or both. Our analysis of the galactic position and velocity relative to the cluster strongly supports the first hypothesis, and puts forward ram pressure as another possible mechanism for feeding the central supermassive black hole with gas.

Hypoparathyroidism after total thyroidectomy: prospective evaluation and relation with early hypocalcemia.

AIM: Definitive hypoparathyrodism (hypo-PTH) represents one of the most dangerous complication after total thyroidectomy. Partial or total lesion or accidental removal of parathyroid glands is an unpredictable adverse event, although real incidence is not well defined, such as management of this deficit. We started a prospective evaluation of patients treated with total thyroidectomy in our centre, to identify incidence of hypo-PTH, symptomatic or not, in relation to incidence of early postoperative hypocalcemia in our experience. METHODS: We prospectively evaluated 177 patients treated for benign and malign pathology, measuring calcium before surgery and calcium and PTH at least three months after surgery. Postoperative hypocalcemia was observed in 37.3% of cases. Eight patients (4.5% of cohort) presented low level of PTH, at mean follow-up of 9.1 months. Positive predictive value for postoperative hypocalcemia was 12.1%, while negative predictive was 95.4%; confirming high sensitivity (100%) and low specificity (65.4%) for detecting hypo-PTH. DISCUSSION: All patients with late hypo-PTH presented hypocalcemia on early analysis, while no case with normal postoperative calcemia accounted with hypo-PTH: this may indicate calcemia as valid prognostic factor of good gland production, when is in the range. Moreover, isolated analysis is too limited to determine real predictability. CONCLUSION: Technical standardization represents the best method for prevention of hypo-PTH. Early hypocalcemia is a prognostic factor, even with a low specificity, of deficit of PTH-production. This observation must be related to other known prognostic factors. Postoperative normal calcemia should be a positive prognostic factor of an acceptable PTHfunction, supported by large cohorts. KEY WORDS: Hypocalcemia, Parathormone, Thyroidectomy.

Surgical approach to TIR3 cytology class A prospective evaluation.

AIM: Fine-needle aspiration (FNA) has proven to be a safe and reliable method of investigation of thyroid lesions. Referencing to European classification, the associated risk of malignancy for TIR3, category reserved for aspirates that contain architectural and/or nuclear atypia, is variable in such studies. Aims of study were evaluating safety of surgical approach, assessing perioperative parameters surgically related, and estimating neoplastic rate for TIR3 group. MATERIAL AND METHODS: A prospective evaluation of all TIR3 submitted to thyroidectomy was conducted by assessing histopatohologic results between January 2005 and December 2012, considering two categories, positive (neoplastic) and negative (not neoplastic) group. Intraoperative and complication rate was analyzed on TIR3 population. RESULTS: A total of 1514 total thyroidectomy was performed from 2005 to 2012: a total of 148 cases was considered on TIR3 group. Positive cases amounted to 64 (43.2%), 29 of which were carcinoma (19.6% of total population) and 35 of which were adenoma, while negative cases amounted to 84 (56.8%). Sensitivity and specificity of TIR3 as neoplastic screening was 43.2% and 82.1%. A total of 32 linfectomies was performed (21.6% of group). Positive group presented a significant lower mean age than negative group (42.1 vs 56.2 years) CONCLUSIONS: TIR3 group represents a various category, with probably different malignancy risk. Our results and neoplasms rate confirmed that surgical option should be gold standard, in order to define atypical pattern and reduce delayed diagnoses. Choice of a second FNA or a imaging monitoring should be adopted for specific condition. KEY WORDS: Fine-needle aspiration, Thyroidectomy, TIR3, Thyroid cancer.

Stochastic model of agent interaction with opinion leaders.

We analyze the problem of agents' interactions in a given population. The purpose of this paper is twofold. Starting from a scheme proposed by Galam [Physica A 320, 571 (2003)], which is based on a majority rule to treat the individuals' interactions, we first study some of its relevant properties. Then, we introduce special individuals, called opinion leaders, who play a key role in information spreading in several practical applications. Opinion leaders have the special feature of strongly interfering with the process based on the majority rule, speeding up the diffusion. We consider a model describing agents' interactions, which encompasses Galam's proposal, where opinion leaders are included as special agents. Then we study its specific properties which significantly recast and extend some conclusions drawn for the models given by Galam and Ellero, Fasano, and Sorato [Physica A 388, 3901 (2009)]. Finally, we provide theoretical and numerical results concerning the dynamics of our model, showing that a small percentage of opinion leaders may both accelerate and/or even reverse the overall consensus among all the agents.