Honest signaling in mouse lemur vocalizations?

Animal vocalizations may provide information about a sender’s condition or motivational state and, hence, mediate social interactions. In this study, we examined whether vocalizations of gray mouse lemurs (Microcebus murinus) emitted in aggressive contexts (grunts, tsaks) co-vary with physical condition, which would underly and indicate honest signaling. We recorded calls from captive individuals that were subjected to a caloric restricted (CR) or ad libitum (AL) diet, assuming that individuals on an ad libitum dietary regime were in better condition. We analyzed 828 grunts produced by seven CR and nine AL individuals and 270 tsaks by eight CR and five AL individuals. Grunts consisted of two separate elements, with the 1st element having more energy in higher frequencies than the 2nd element. Body mass correlated negatively with acoustic features of grunts, and heavier individuals produced lower-frequency grunts. Acoustic features of grunts did not differ between sexes. Acoustic features of tsaks were predicted by neither body mass nor sex. However, tsaks produced by AL individuals were noisier than those of CR individuals. Hence, manipulation of body condition via dietary regimes affected acoustic features of calls given during aggression in different ways: acoustic features of grunts varied according to the rule of acoustic allometry, and can be considered as honest signals. Acoustic features of tsaks, however, varied according to motivational structural rules. Longitudinal studies are now indicated to examine whether intra-individual changes in body mass are also reflected in the acoustic structure of calls, allowing callers to signal more flexible variation in condition.

LIFE-CYCLE CO2 EMISSIONS OF BULK CARRIERS: A COMPARATIVE STUDY

In order to maintain shipping capacity to serve seaborne trade, new ships have to be built to replace those scrapped. The cost of building, manning, operating, maintaining and repairing a ship throughout its life is borne by society at large through market mechanisms. Gratsos and Zachariadis (2005) had investigated through a cost/benefit analysis how the average annual cost of ship transport varies with the corrosion additions elected at the design stage. The results of that paper clearly indicated that ships built with sufficient corrosion allowances, truly adequate for the ship’s design life, have a lower life cycle cost per annum despite the fact that such ships would carry a slightly smaller quantity of cargo. Furthermore the safety and environmental benefits due to the reduced repairs and extended lifetime of such ships were briefly discussed. The debate of how “robust” a ship should be was also transferred to IMO in the context of Goal Based Standards following a submission by Japan which stated that the increased steel weight of a more robust ship will result in increased CO2 emissions due to a reduced cargo carrying capacity. Greece replied by submitting a summary of the aforementioned paper and preliminary estimations on Life cycle CO2 emissions disputing the Japanese contentions. However, taking onboard the challenge, an update is provided in the present paper, using the final Common Structural Rules (CSR) of the International Association of Classification Societies (IACS) bulk carrier corrosion margins and taking into account the major environmental implications of the heavier ship scantlings for two bulk carrier size brackets, Panamax and Handymax. The results show that the more robust ships would produce less CO2 emissions over their lifetime.

Impact of high strength steels over large ships fore peak structure

The fore area of the ships in extreme conditions is commonly subjected to external impact pressures such as bottom slamming and bow impact. The phenomenon combined with a poor design can lead to local structural damage (cracks, dents, buckling of plate panels) and malfunction to the installations on-board of the ship. In the present article, a comparison study between different steel material grades is performed for a VLCC fore peak structure subjected to external and internal dynamic pressures under the Harmonized Common Structural Rules for Bulk Carriers and Oil Tankers (H-CSR). Three steel grades generally used in the shipbuilding industry, one normal strength and two higher strength, are subjected for the assessment. The hull structure is built based on the benchmark crude oil carrier KVLCC2 surface developed by KRISO (Korea Research Institute for Ships and Ocean Engineering, and modelled with plate finite elements in FEMAP software. The study targets an optimization process to minimize the steel weight of the structural members by plate elements thickness reduction.

Improving Institutional Repositories through User-Centered Design: Indicators from a Focus Group

User experience with intuitive and flexible digital platforms can be enjoyable and satisfying. A strategy to deliver such an experience is to place the users at the center of the design process and analyze their beliefs and perceptions to add appropriate platform features. This study conducted with focus groups as a qualitative method of data collection to investigate users’ preferences and develop a new landing page for institutional repositories with attractive functionalities based on their information-structural rules. The research question was: What are the motivations and experiences of users in an academic community when publishing scientific information in an institutional repository? The focus group technique used in this study had three sessions. Results showed that 50% of the participants did not know the functionalities of the institutional repository nor its benefits. Users’ perceptions of platforms such as ResearchGate or Google Scholar that provide academic production were also identified. The findings showed that motivating an academic community to use an institutional repository requires technological functions, user guidelines that identify what can or cannot be published in open access, and training programs for open access publication practices and institutional repository use. These measures align with global strategies to strengthen the digital identities of scientific communities and thus benefit open science.

Structural Interface for Automated Compliance Checking

This paper describes the benefits of cost reduction and improved schedule attainment by adding digitized regulatory structural rules and contract specification requirements to the 3D design model through Knowledge Provisioning.

Sequent Systems without Improper Derivations

In the natural deduction system for classical propositional logic given by G. Gentzen, there are some inference rules with assumptions discharged by the rule. D. Prawitz calls such inference rules improper, and others proper. Improper inference rules are more complicated and are often harder to understand than the proper ones. In the present paper, we distinguish between proper and improper derivations by using sequent systems. Specifically, we introduce a sequent system \(\vdash_{\bf Sc}\) for classical propositional logic with only structural rules, and prove that \(\vdash_{\bf Sc}\) does not allow improper derivations in general. For instance, the sequent \(\Rightarrow p \to q\) cannot be derived from the sequent \(p \Rightarrow q\) in \(\vdash_{\bf Sc}\). In order to prove the failure of improper derivations, we modify the usual notion of truth valuation, and using the modified valuation, we prove the completeness of \(\vdash_{\bf Sc}\). We also consider whether an improper derivation can be described generally by using \(\vdash_{\bf Sc}\).

Construction of surrogate models for predicting the buckling strength of stiffened panels through DoE and RSM methods

PurposeExperimental mid/large scale testing of ship-like stiffened panels in compression is a quite expensive exercise that is not standard. Numerical simulations are preferred instead. Because of being relatively inexpensive (cost and time wise), most authors perform an exhaustive design space exploration arriving at a significant number of runs. This work demonstrates that the buckling response with respect to the nondimensional slenderness ratios may well be fitted with nine runs per stiffener geometry.Design/methodology/approachEfficient derivation of buckling strength formulas for stiffened panels through the employment of design of experiments (DoE) and response surface methodology (RSM) combined with numerical nonlinear experimentation over the entire range of practical geometries.FindingsThe surrogate model developed for T-bar stiffeners predicts accurately enough the ultimate stress in the practical design area, while the surrogate models for angle bars and flat bars demonstrate difference between 10 and 30% from common structural rules (CSR).Originality/valueTo the authors' best knowledge, the statistical-based formal and rigorous approach of DoE and RSM to obtaining buckling surfaces for stiffened panels is performed for the first time. The number of required observations per stiffener type has not been addressed yet as each work selects its own sampling scheme without formal reasoning. This work comes to frame the number of observations for efficient surrogate model building.

Language statistical learning responds to reinforcement learning principles rooted in the striatum

Statistical learning (SL) is the ability to extract regularities from the environment. In the domain of language, this ability is fundamental in the learning of words and structural rules. In lack of reliable online measures, statistical word and rule learning have been primarily investigated using offline (post-familiarization) tests, which gives limited insights into the dynamics of SL and its neural basis. Here, we capitalize on a novel task that tracks the online SL of simple syntactic structures combined with computational modeling to show that online SL responds to reinforcement learning principles rooted in striatal function. Specifically, we demonstrate—on 2 different cohorts—that a temporal difference model, which relies on prediction errors, accounts for participants’ online learning behavior. We then show that the trial-by-trial development of predictions through learning strongly correlates with activity in both ventral and dorsal striatum. Our results thus provide a detailed mechanistic account of language-related SL and an explanation for the oft-cited implication of the striatum in SL tasks. This work, therefore, bridges the long-standing gap between language learning and reinforcement learning phenomena.

DRAWING INSPIRATION FROM THE SPINE, DESIGNING A PEDESTRIAN BRIDGE [SPINE-INSPIRED DESIGN OF A PEDESTRIAN BRIDGE]

Natural structures are known to be the source of inspiration for numerous architectural and structural rules in the fields of aesthetics, function, and structure; therefore, the application of the principals governing them could be used for appropriate and optimal design. The present paper was conducted to model the natural structure of load transfer in order to design the structure of a pedestrian bridge with a span of 100 meters. This bridge is located in a mountain park in the tourist area of Kashan, 230 km south of Tehran. For this purpose, by examining the patterns in the nature, which provides a relevant answer to the problem, the spine of animals was identified as the bearing skeleton of the body, the best option for patterning. Inspired by it, a stable structure was designed as a skeleton of a bridge without a middle pillar. Based on a form inspired by the spine of a four-legged animal, the bridge structure was designed. To control the stability of the bridge structure against the loads, the initial design idea was analysed employing the Karamba plugin in Grasshopper software to identify its weaknesses and the final design was obtained. The final design was analysed with SAP2000 structural finite element software to ensure the stability and control of permissible deformations. Additionally, attention to the modular structure of the spine was the source of inspiration for the design of prefabricated elements of the bridge parts, which in addition to reducing the cost of execution, increases the speed of construction of the project. The final design of the pedestrian bridge, which acts similar to a suspension bridge in terms of load transfer and was inspired by the structure of a four-legged vertebrate, is a combination of truss and tensegrity structure and in addition to visual aesthetic, has optimal structural performance.