Influential Listeners: An Experiment on Persuasion Bias in Social Networks

This paper presents an experimental investigation of persuasion bias, a form of bounded rationality whereby agents communicating through a social network are unable to account for possible repetitions in the information they receive. The results indicate that network structure plays a significant role in determining social influence. However, the most influential agents are not those with more outgoing links, as predicted by the persuasion bias hypothesis, but those with more incoming links. We show that a boundedly rational updating rule that takes into account not only agents' outdegree, but also their indegree, provides a better explanation of the experimental data. In this framework, consensus beliefs tend to be swayed towards the opinions of influential listeners. We then present an effort-weighted updating model as a more general characterization of information aggregation in social networks.

Towards a Near-real-time Protocol Tunneling Detector based on Machine Learning Techniques

In the very last years, cybersecurity attacks have increased at an unprecedented pace, becoming ever more sophisticated and costly. Their impact has involved both private/public companies and critical infrastructures. At the same time, due to the COVID-19 pandemic, the security perimeters of many organizations expanded, causing an increase of the attack surface exploitable by threat actors through malware and phishing attacks. Given these factors, it is of primary importance to monitor the security perimeter and the events occurring in the monitored network, according to a tested security strategy of detection and response. In this paper, we present a protocol tunneling detector prototype which inspects, in near real time, a company's network traffic using machine learning techniques. Indeed, tunneling attacks allow malicious actors to maximize the time in which their activity remains undetected. The detector monitors unencrypted network flows and extracts features to detect possible occurring attacks and anomalies, by combining machine learning and deep learning. The proposed module can be embedded in any network security monitoring platform able to provide network flow information along with its metadata. The detection capabilities of the implemented prototype have been tested both on benign and malicious datasets. Results show 97.1% overall accuracy and an F1-score equals to 95.6%.Comment: 12 pages, 4 figures, 4 table

Charge Carrier Mobility in Organic Mixed Ionic–Electronic Conductors by the Electrolyte-Gated van der Pauw Method

Organic mixed ionic–electronic conductors (OMIECs) combine electronic semiconductor functionality with ionic conductivity, biocompatibility, and electrochemical stability in water and are currently investigated as the active material in devices for bioelectronics, neuromorphic computing, as well as energy conversion and storage. Operation speed of such devices depends on fast electronic transport in OMIECs. However, due to contact resistance problems, reliable measurements of electronic mobility are difficult to achieve in this class of materials. To address the problem, the electrolyte-gated van der Pauw (EgVDP) method is introduced for the simple and accurate determination of the electrical characteristics of OMIEC thin films, independent of contact effects. The technique is applied to the most widespread OMIEC blend, poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (PEDOT:PSS). By comparing with organic electrochemical transistor (OECT) measurements, it is found that gate voltage dependent contact resistance effects lead to systematic errors in OECT based transport characterization. These observations confirm that a contact-independent technique is crucial for the proper characterization of OMIECs, and the EgVDP method reveals to be a simple, elegant, but effective technique for this scope

Opposite effects of high- and low-frequency transcranial random noise stimulation probed with visual motion adaptation

Transcranial random noise stimulation (tRNS) is a recent neuro-modulation technique whose effects at both behavioural and neural level are still debated. Here we employed the well-known phenomenon of motion after-effect (MAE) in order to investigate the effects of high- vs. low-frequency tRNS on motion adaptation and recovery. Participants were asked to estimate the MAE duration following prolonged adaptation (20 s) to a complex moving pattern, while being stimulated with either sham or tRNS across different blocks. Different groups were administered with either high- or low-frequency tRNS. Stimulation sites were either bilateral human MT complex (hMT+) or frontal areas. The results showed that, whereas no effects on MAE duration were induced by stimulating frontal areas, when applied to the bilateral hMT+, high-frequency tRNS caused a significant decrease in MAE duration whereas low-frequency tRNS caused a significant corresponding increase in MAE duration. These findings indicate that high- and low-frequency tRNS have opposed effects on the adaptation-dependent unbalance between neurons tuned to opposite motion directions, and thus on neuronal excitability

Qualitative and quantitative evaluation of biogenic amines in vitro production by bacteria isolated from ewes' milk cheeses

Studying the production of biogenic amines (BA) by cheese microbiota is important, because high BA concentrations in food represent a health risk for consumers. Qualitative screening with differential media and HPLC quantification were used to investigate the production of 8 BA (2-phenylethylamine, cadaverine, histamine, putrescine, spermidine, spermine, tryptamine, and tyramine) by 72 isolates from curd and cheese samples manufactured with raw and pasteurised ewes' milk. Enterobacteriaceae showed good putrescine and cadaverine production, both for number of positive isolates and for concentrations produced (average: 341 and 785 micrograms/ml, respectively). Among Enterobacteriaceae data are provided on BA formation by Pantoea conspicua, previously not isolated from food samples. All enterococci formed tyramine, often in high amounts (average: 1608 micrograms/ml), and many produced notable 2-phenylethylamine, putrescine, and cadaverine concentrations (average: 184, 121, and 146 micrograms/ml, respectively). BA formation by lactobacilli was overall extremely limited, with the notable exception of high tyramine concentrations produced by 1 Lactobacillus paracasei (800 micrograms/ml) and 2 Lactobacillus curvatus (> 1700 micrograms/ml), all isolated from pasteurised milk samples. Thus, undesired and technologically useful microorganisms both play a role in BA accumulation in cheeses

AC amplification gain in organic electrochemical transistors for impedance-based single cell sensors

Research on electrolyte-gated and organic electrochemical transistor (OECT) architectures is motivated by the prospect of a highly biocompatible interface capable of amplifying bioelectronic signals at the site of detection. Despite many demonstrations in these directions, a quantitative model for OECTs as impedance biosensors is still lacking. We overcome this issue by introducing a model experiment where we simulate the detection of a single cell by the impedance sensing of a dielectric microparticle. The highly reproducible experiment allows us to study the impact of transistor geometry and operation conditions on device sensitivity. With the data we rationalize a mathematical model that provides clear guidelines for the optimization of OECTs as single cell sensors, and we verify the quantitative predictions in an in-vitro experiment. In the optimized geometry, the OECT-based impedance sensor allows to record single cell adhesion and detachment transients, showing a maximum gain of 20.2±0.9 dB with respect to a single electrode-based impedance sensor

Investigation of ancient DNA to enhance natural history museum collections: misidentification of smooth-coated otter (Lutrogale perspicillata) specimens across multiple museums

Historical and modern natural museum collections are storehouses of extraordinary value for scientific research in a wide range of fields. Recent advances in molecular biotechnology (e.g., next generation genomics) have increased the range of collection material employable for DNA-based analyses to unprecedented levels. Nevertheless, the value of museum specimens strictly depends on reliability of data associated with them. We report on investigations of ancient DNA from specimens of smooth-coated otter (Lutrogale perspicillata, Mustelidae), the largest otter species living in Asia, in US and European mammal collections. Mitochondrial DNA Cytochrome-b gene sequencing proved that the studied specimens were not the expected taxon. Indeed, they actually belonged to three different species, namely the Asian small-clawed (Aonyx cinereus), Eurasian (Lutra lutra) and African clawless (Aonyx capensis) otters. This represents the first record of mustelid misidentification from museum collections. Detection of errors can be extremely difficult when based only on collectors’ notes and data. Hence, we warn scientists involved in otter research about potential challenges when dealing with museum specimens. We recommend curators pursue a multidisciplinary approach, including DNA analyses, to accurately catalogue the resources under their management and uphold the value of biodiversity information

Subcellular localization of the five members of the human steroid 5α-reductase family

In humans the steroid 5a-reductase (SRD5A) family comprises five integral membrane enzymes that carry out reduction of a double bond in lipidic substrates: D4-3-keto steroids, polyprenol and trans-enoyl CoA. The best-characterized reaction is the conversion of testosterone into the more potent dihydrotestosterone carried out by SRD5A1-2. Some controversy exists on their possible nuclear or endoplasmic reticulum localization. We report the cloning and transient expression in HeLa cells of the five members of the human steroid 5a-reductase family as both N- and Cterminus green fluorescent protein tagged protein constructs. Following the intrinsic fluorescence of the tag, we have determined that the subcellular localization of these enzymes is in the endoplasmic reticulum, upon expression in HeLa cells. The presence of the tag at either end of the polypeptide chain can affect protein expression and, in the case of trans enoyl-CoA reductase, it induces the formation of protein aggregates

Disseminated and Relapsing Cryptococcosis: What We Still Have to Learn—a Case Series and Review of Literature

AbstractTwo cases of disseminated cryptococcosis are described. The first was an HIV-infected patient where cryptococcosis was diagnosed as "unmasking immune reconstitution syndrome"; the second was an immunosuppressed patient with multiple myeloma. In both cases, a definitive healing could not be reached despite long therapeutic approaches. This review summarizes both the most recent and relevant studies about disseminated and refractory form of cryptococcal infections and identifies research gaps. Given the limited data, we draw some conclusions with respect to management from literature: not clear and accepted indication are available regarding disseminated cryptococcosis, no specific schemes were identified, and the duration of therapy is usually decided case by case and supported only by case reports. In this perspective, usually standard therapeutic schemes and duration of induction depend on multiple factors (e.g., neurologic deficit, non-HIV/non transplant status, CSF culture positivity at 2 weeks, etc.). We found that there are no empiric and literature data that support a role of cryptococcal serum antigen (CRAG) in guiding the antifungal therapy; with the data collected, we think that although is possible, it is very rare to find disseminated cryptococcosis with negative CRAG. We looked also for the more important risk factor of recurrence. Some possible causes explored are risk of azole resistant strains, pre-existent conditions of patients that play a permissive role and the common situation where flucytosine is unavailable that led to suboptimal induction phase of therapy. Herein, we discuss disseminated cryptococcosis with a particular attention to antifungal therapy, role of cryptococcal antigen, and risk factors for recurrence of disease

Staphylococcus aureus growth and enterotoxin production in Italian caciotta cheese

To evaluate growth and enterotoxin production of Staphylococcus aureus in raw milk caciotta, an Italian soft cheese, experimental cheesemaking trials were carried out with and without a commercial starter. Two different inocula of selected enterotoxinproducing S. aureus strains were tested: high (mean value 5.03 log CFU/mL of milk) and low (mean value 3.22 log CFU/mL of milk). Uninoculated cheeses with milk containing 2.15 log CFU/mL mean value of coagulase-positive staphylococci were also examined. With higher inocul a coagulase-positive staphylococci counts reached 7.57 log CFU/g without starter and had significantly higher values after the acidification phase than those with starter (below 6.5 log CFU/g). Using an enzyme immunoassay, enterotoxins were detected in cheeses both without and with starter, but the latter showed significantly lower photometrical absorbance values than the former. In low inoculum and uninoculated cheeses without starter, coagulase-positive staphylococci maximum values were between 5 and 6 log CFU/g, without enterotoxin production. To enhance the safety of this cheese it is fundamental to strictly prevent coagulase-positive staphylococci contamination and multiplication, particularly at the primary production level, and to correctly acidify the curd by starter cultures, which can substantially limit total coagulase-positive staphylococci increase