Use of whistles for acoustic classification of delphinids (odontoceti: Delphinidae) in the Western South Atlantic Ocean.

This study focuses on the acoustic classification of delphinid species at the southern continental slope of Brazil. Recordings were collected between 2013 and 2015 using towed arrays and were processed using a classifier to identify the species in the recordings. Using Raven Pro 1.6 software (Cornell Laboratory of Ornithology, Ithaca, NY), we analyzed whistles for species identification. The random forest algorithm in R facilitates classification analysis based on acoustic parameters, including low, high, delta, center, beginning, and ending frequencies, and duration. Evaluation metrics, such as correct and incorrect classification percentages, global accuracy, balanced accuracy, and p-values, were employed. Receiver operating characteristic curves and area-under-the-curve (AUC) values demonstrated well-fitting models (AUC ≥ 0.7) for species definition. Duration and delta frequency emerged as crucial parameters for classification, as indicated by the decrease in mean accuracy. Multivariate dispersion plots visualized the proximity between acoustic and visual match data and exclusively acoustic encounter (EAE) data. The EAE results classified as Delphinus delphis (n = 6), Stenella frontalis (n = 3), and Stenella longirostris (n = 2) provide valuable insights into the presence of these species between approximately 23° and 34° S in Brazil. This study demonstrates the effectiveness of acousting classification in discriminating delphinids through whistle parameters.

When Measurements Meet Blockchain: On Behalf of an Inter-NMI Network.

The growing demand for solutions related to measurement (e.g., digital sensors, smart meters, distributed measuring systems) imposes several concerns about information and process reliability. In this context, blockchain can play a crucial role as a platform to implement applications and activities in the context of legal metrology. In most countries, the National Metrology Institutes (NMIs) are responsible for promoting these initiatives. Thus, in this paper, we present a functional architecture to integrate NMIs in a collaborative blockchain network. We discuss the main aspects and features that an inter-NMI blockchain network must deliver. Furthermore, we implement our proposal using the Hyperledger Fabric platform. We connect peers from Physikalisch-Technische Bundesanstalt (PTB) (German NMI) and the National Institute of Metrology, Quality, and Technology (Inmetro) (Brazilian NMI) in a useful application that consists of a blockchain-based public-key infrastructure to identify and authenticate smart meters. Our preliminary results demonstrate that the proposed architecture meets the main requirements imposed by applications involving measurements. Furthermore, it opens the opportunity to integrate NMIs from other countries into the project, constituting an important global initiative in the metrology field.

Quantitative Metrics for Performance Monitoring of Software Code Analysis Accredited Testing Laboratories.

Modern sensors deployed in most Industry 4.0 applications are intelligent, meaning that they present sophisticated behavior, usually due to embedded software, and network connectivity capabilities. For that reason, the task of calibrating an intelligent sensor currently involves more than measuring physical quantities. As the behavior of modern sensors depends on embedded software, comprehensive assessments of such sensors necessarily demands the analysis of their embedded software. On the other hand, interlaboratory comparisons are comparative analyses of a body of labs involved in such assessments. While interlaboratory comparison is a well-established practice in fields related to physical, chemical and biological sciences, it is a recent challenge for software assessment. Establishing quantitative metrics to compare the performance of software analysis and testing accredited labs is no trivial task. Software is intangible and its requirements accommodate some ambiguity, inconsistency or information loss. Besides, software testing and analysis are highly human-dependent activities. In the present work, we investigate whether performing interlaboratory comparisons for software assessment by using quantitative performance measurement is feasible. The proposal was to evaluate the competence in software code analysis activities of each lab by using two quantitative metrics (code coverage and mutation score). Our results demonstrate the feasibility of establishing quantitative comparisons among software analysis and testing accredited laboratories. One of these rounds was registered as formal proficiency testing in the database-the first registered proficiency testing focused on code analysis.

A Triggering Mechanism for Cyber-Attacks in Naval Sensors and Systems.

In the maritime sector, the integration of radar systems, Automatic Identification System (AIS) and Electronic Chart Display and Information System (ECDIS) through digital technologies enables several benefits to maritime operations, but also make ships prone to cyberattacks. In this context, this work investigates the feasibility of an attacker using a radar system or AIS as open door to remotely send commands to a cyber threat hosted on a ship, even if the ship's systems are air gapped-i.e., are not connected to other networks. The received commands are intended to trigger a cyber threat located in the ship. Although the literature covers several analyzes on cyber risks and vulnerabilities in naval systems, it lacks exploiting mechanisms capable of acknowledging attack commands received through radar and AIS. To this end, this work proposes a triggering mechanism that uses a template matching technique to detect specific patterns transmitted by the attacker to the ship's radar or AIS. The results show the effectiveness of the proposed technique as a tool to acknowledge the received attack commands and activate a malicious code previously installed on the ship. In the case of attacks on a radar system, the accuracy achieved by the proposed method is 0.90. In the case of attacks on an AIS/ECDIS setup it presents an accuracy of 0.93. In both cases the proposed mechanism maintains the due safety against accidental attack activations.

Identification of Data Injection Attacks in Networked Control Systems Using Noise Impulse Integration.

The benefits of using Networked Control Systems (NCS) in the growing Industry 4.0 arenumerous, including better management and operational capabilities, as well as costs reduction.However, despite these benefits, the use of NCSs can also expose physical plants to new threatsoriginated in the cyber domain-such as data injection attacks in NCS links through which sensorsand controllers transmit signals. In this sense, this work proposes a link monitoring strategy toidentify linear time-invariant (LTI) functions executed during controlled data injection attacksby a Man-in-the-Middle hosted in an NCS link. The countermeasure is based on a bioinspiredmetaheuristic, called Backtracking Search Optimization Algorithm (BSA), and uses white Gaussiannoise to excite the attack function. To increase the accuracy of this countermeasure, it is proposedthe Noise Impulse Integration (NII) technique, which is developed using the radar pulse integrationtechnique as inspiration. The results demonstrate that the proposed countermeasure is able toaccurately identify LTI attack functions, here executed to impair measurements transmitted bythe plant sensor, without interfering with the NCS behavior when the system is in its normaloperation. Moreover, the results indicate that the NII technique can increase the accuracy of the attackidentification.

Nanostructured and Photochromic Material for Environmental Detection of Metal Ions.

Compared to conventional spectroscopy or chromatography analysis, chemical sensing based on colorimetric changes offers an alternative to monitor potential metal hazards in aqueous environment through rapid and low-cost colorimetric changes which can be easily interpreted. In this work poly(ethylene glycol) (PEG 2000) was modified with a carboxylic acid spiropyran (SPCOOH) derivate by Steglich esterification (PEGSP2). PEGSP2 was incorporated into a poly(-caprolactone) (PCL) polymer matrix by electrospinning technique to produce nanofibers with photochromic properties. Spectroscopic analysis, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to characterize PEGSP2. Drop shape analysis (DSA) and scanning electronic microscopy (SEM) were used to characterize the electrospun (ES) nanofibers morphology. Several metal ions solutions relevant to environmental hazards were prepared to be spotted on the surface of ES nanofibers for photochromatic sensing. Among them, Mg2+, Ca2+, Zn2+, Cd2+, La3+, and Er3+ demonstrated orange fluorescence when exposed to UV light. ES nanofibers also presented higher wettability when compared to a pure PCL polymer matrix, which is critical for sensitivity. Eighteen metals ions could be detected on the electrospun material. Additionally, among all metal ions Fe3+ was the most sensitive one in solution, in a µmol L1 range.

Restricted DCJ-indel model: sorting linear genomes with DCJ and indels.

BACKGROUND: The double-cut-and-join (DCJ) is a model that is able to efficiently sort a genome into another, generalizing the typical mutations (inversions, fusions, fissions, translocations) to which genomes are subject, but allowing the existence of circular chromosomes at the intermediate steps. In the general model many circular chromosomes can coexist in some intermediate step. However, when the compared genomes are linear, it is more plausible to use the so-called restricted DCJ model, in which we proceed the reincorporation of a circular chromosome immediately after its creation. These two consecutive DCJ operations, which create and reincorporate a circular chromosome, mimic a transposition or a block-interchange. When the compared genomes have the same content, it is known that the genomic distance for the restricted DCJ model is the same as the distance for the general model. If the genomes have unequal contents, in addition to DCJ it is necessary to consider indels, which are insertions and deletions of DNA segments. Linear time algorithms were proposed to compute the distance and to find a sorting scenario in a general, unrestricted DCJ-indel model that considers DCJ and indels. RESULTS: In the present work we consider the restricted DCJ-indel model for sorting linear genomes with unequal contents. We allow DCJ operations and indels with the following constraint: if a circular chromosome is created by a DCJ, it has to be reincorporated in the next step (no other DCJ or indel can be applied between the creation and the reincorporation of a circular chromosome). We then develop a sorting algorithm and give a tight upper bound for the restricted DCJ-indel distance. CONCLUSIONS: We have given a tight upper bound for the restricted DCJ-indel distance. The question whether this bound can be reduced so that both the general and the restricted DCJ-indel distances are equal remains open.

On the weight of indels in genomic distances.

BACKGROUND: Classical approaches to compute the genomic distance are usually limited to genomes with the same content, without duplicated markers. However, differences in the gene content are frequently observed and can reflect important evolutionary aspects. A few polynomial time algorithms that include genome rearrangements, insertions and deletions (or substitutions) were already proposed. These methods often allow a block of contiguous markers to be inserted, deleted or substituted at once but result in distance functions that do not respect the triangular inequality and hence do not constitute metrics. RESULTS: In the present study we discuss the disruption of the triangular inequality in some of the available methods and give a framework to establish an efficient correction for two models recently proposed, one that includes insertions, deletions and double cut and join (DCJ) operations, and one that includes substitutions and DCJ operations. CONCLUSIONS: We show that the proposed framework establishes the triangular inequality in both distances, by summing a surcharge on indel operations and on substitutions that depends only on the number of markers affected by these operations. This correction can be applied a posteriori, without interfering with the already available formulas to compute these distances. We claim that this correction leads to distances that are biologically more plausible.

Genomic distance under gene substitutions.

BACKGROUND: The distance between two genomes is often computed by comparing only the common markers between them. Some approaches are also able to deal with non-common markers, allowing the insertion or the deletion of such markers. In these models, a deletion and a subsequent insertion that occur at the same position of the genome count for two sorting steps. RESULTS: Here we propose a new model that sorts non-common markers with substitutions, which are more powerful operations that comprehend insertions and deletions. A deletion and an insertion that occur at the same position of the genome can be modeled as a substitution, counting for a single sorting step. CONCLUSIONS: Comparing genomes with unequal content, but without duplicated markers, we give a linear time algorithm to compute the genomic distance considering substitutions and double-cut-and-join (DCJ) operations. This model provides a parsimonious genomic distance to handle genomes free of duplicated markers, that is in practice a lower bound to the real genomic distances. The method could also be used to refine orthology assignments, since in some cases a substitution could actually correspond to an unannotated orthology.

Microsurgical resection of a giant cervico-medullary ependymoma: 2D-dimensional video.

BACKGROUND: Ependymoma is a slowly growing benign neoplasm that constitutes 3-9% of all neuroepithelial spinal cord tumors.[3,4] They rarely involve the cervicomedullary junction where they both compress the distal brainstem and upper cervical cord. Due to the critical contiguous structures, gross total resection of these lesions may result in significant morbidity/mortality.[1,2] Utilizing intraoperative neuromonitoring can help limit the risks of removing these lesions. Not when considering the risk/complications of partial versus total resection, the surgeon should keep in mind that they are benign slow growing tumors with relatively good long-term survivals following partial removals. This surgical video shows the surgical strategy and management of a giant cervicomedullary ependymoma performed in a 23-year-old female. CASE DESCRIPTION: A 23-year-old female presented with cervical pain and quadriparesis of 1-year's duration. The MR with/without gadolinium showed a large intradural, intramedullary cervical spinal cord tumor that severely expanded the spinal cord. It contained a significant cystic component, extending from the lower brain stem to the inferior aspect of C7. The lesion was hyperintense on T1 and T2 sequences and demonstrated minimal contrast enhancement. Surgery warranted a posterior cranio-cervical midline approach consisting of a suboccipital craniectomy with laminotomy. The pathological diagnosis was consistent with an ependymoma (WHO I). Fifteen days postoperatively, the patient was discharged with a minimal residual quadriparesis that largely resolved within 6 postoperative months. Three months later, the MRI confirmed complete tumor removal of the lesion. Notably, longer-term follow-up is warranted before complete excision can be confirmed. If there is a recurrence, repeat resection versus stereotactic radiosurgery may be warranted. CONCLUSION: This video highlights a safe and effective surgical technique for the resection of a giant cervicomedullary ependymoma.

Genomic Distance with High Indel Costs.

We determine complexity of computing the DCJ-indel distance, when DCJ and indel operations have distinct constant costs, by showing an exact formula that can be computed in linear time for any choice of (constant) costs for DCJ and indel operations. We additionally consider the problem of triangular inequality disruption and propose an algorithmically efficient correction on each member of the family of DCJ-indel.

DCJ-indel and DCJ-substitution distances with distinct operation costs.

BACKGROUND: Classical approaches to compute the genomic distance are usually limited to genomes with the same content and take into consideration only rearrangements that change the organization of the genome (i.e. positions and orientation of pieces of DNA, number and type of chromosomes, etc.), such as inversions, translocations, fusions and fissions. These operations are generically represented by the double-cut and join (DCJ) operation. The distance between two genomes, in terms of number of DCJ operations, can be computed in linear time. In order to handle genomes with distinct contents, also insertions and deletions of fragments of DNA - named indels - must be allowed. More powerful than an indel is a substitution of a fragment of DNA by another fragment of DNA. Indels and substitutions are called content-modifying operations. It has been shown that both the DCJ-indel and the DCJ-substitution distances can also be computed in linear time, assuming that the same cost is assigned to any DCJ or content-modifying operation. RESULTS: In the present study we extend the DCJ-indel and the DCJ-substitution models, considering that the content-modifying cost is distinct from and upper bounded by the DCJ cost, and show that the distance in both models can still be computed in linear time. Although the triangular inequality can be disrupted in both models, we also show how to efficiently fix this problem a posteriori.