Statistical modelling reveals spatial, temporal, and environmental preferences for white sharks at an oceanic aggregation site

2020 ◽  
Vol 655 ◽  
pp. 171-183
Author(s):  
EE Becerril-García ◽  
RO Martínez-Rincón ◽  
F Galván-Magaña ◽  
O Santana-Morales ◽  
EM Hoyos-Padilla
Keyword(s):  
Feeding Habits ◽  
Generalized Additive Models ◽  
Statistical Modelling ◽  
Time Of Day ◽  
White Shark ◽  
Additive Models ◽  
Environmental Preferences ◽  
Data Set ◽  
Aggregation Site ◽  
Guadalupe Island

Guadalupe Island, Mexico, is one of the most important white shark (Carcharodon carcharias) aggregation sites in the Eastern Pacific. In the waters surrounding Guadalupe Island, cage diving has been carried out since 2001 during August-November; however, there is scarce information regarding the factors associated with this seasonal aggregation. The purpose of this study was to describe the probability of occurrence of white sharks relative to spatial, temporal, and environmental factors in Guadalupe Island. Generalized additive models (GAMs) were used to describe the effect of sea surface temperature, water visibility, tide, moon phase, cloud cover, time of day, and location on white shark occurrence. GAMs were generated from a data set of 6266 sightings of white sharks, classified as immature males, mature males, immature females, and mature females. A sexual segregation related to month was observed, where females arrived after males during late September. GAMs evidenced a segregation of white sharks according to the analysed variables, which is consistent with previous observations in this locality. Environmental preferences for each white shark category are potentially influenced by feeding habits, sexual maturation, and reproduction. This study constitutes a baseline of the effect of the environment on the occurrence of white sharks in Guadalupe Island, which can be used in further studies regarding management and conservation in future climatic and anthropogenic scenarios. Its relevance is related to the understanding of its ecology in oceanic environments and the presence of this threatened species during the ecotourism season.

scholarly journals Environmental conditions are poor predictors of immature white shark Carcharodon carcharias occurrences on coastal beaches of eastern Australia

2020 ◽  
Vol 653 ◽  
pp. 167-179
Author(s):  
JLY Spaet ◽  
A Manica ◽  
CP Brand ◽  
C Gallen ◽  
PA Butcher
Keyword(s):  
Environmental Conditions ◽  
Prey Availability ◽  
Statistical Significance ◽  
Time Of Day ◽  
White Shark ◽  
Additive Models ◽  
Large Sample Size ◽  
Lunar Phase ◽  
Carcharodon Carcharias ◽  
Eastern Australia

Understanding and predicting the distribution of organisms in heterogeneous environments is a fundamental ecological question and a requirement for sound management. To implement effective conservation strategies for white shark Carcharodon carcharias populations, it is imperative to define drivers of their movement and occurrence patterns and to protect critical habitats. Here, we acoustically tagged 444 immature white sharks and monitored their presence in relation to environmental factors over a 3 yr period (2016-2019) using an array of 21 iridium satellite-linked (VR4G) receivers spread along the coast of New South Wales, Australia. Results of generalized additive models showed that all tested predictors (month, time of day, water temperature, tidal height, swell height, lunar phase) had a significant effect on shark occurrence. However, collectively, these predictors only explained 1.8% of deviance, suggesting that statistical significance may be rooted in the large sample size rather than biological importance. On the other hand, receiver location, which captures geographic fidelity and local conditions not captured by the aforementioned environmental variables, explained a sizeable 17.3% of deviance. Sharks tracked in this study hence appear to be tolerant to episodic changes in environmental conditions, and movement patterns are likely related to currently undetermined, location-specific habitat characteristics or biological components, such as local currents, prey availability or competition. Importantly, we show that performance of VR4G receivers can be strongly affected by local environmental conditions, and provide an example of how a lack of range test controls can lead to misinterpretation and erroneous conclusions of acoustic detection data.

scholarly journals A tutorial on regression-based norming of psychological tests with GAMLSS (version 3)

2019 ◽  
Author(s):  
Marieke Timmerman ◽  
Lieke Voncken ◽  
Casper J Albers
Keyword(s):  
Generalized Additive Models ◽  
Reference Population ◽  
Psychological Tests ◽  
Additive Models ◽  
Normative Study ◽  
Data Set ◽  
Composite Scale ◽  
Sample Data ◽  
Proper Interpretation ◽  
Multiple Reference

A norm-referenced score expresses the position of an individual test taker in the reference population, thereby enabling a proper interpretation of the test score. Such normed scores are derived from test scores obtained from a sample of the reference population. Typically, multiple reference populations exist for a test, namely when the norm-referenced scores depend on individual characteristic(s), as age (and sex). To derive normed scores, regression-based norming has gained large popularity. The advantages of this method over traditional norming are its flexible nature, yielding potentially more realistic norms, and its efficiency, requiring potentially smaller sample sizes to achieve the same precision. In this tutorial, we introduce the reader to regression-based norming, using the generalized additive models for location, scale, and shape (GAMLSS). This approach has been useful in norm estimation of various psychological tests. We discuss the rationale of regression-based norming, theoretical properties of GAMLSS, and their relationships to other regression-based norming models. Based on six steps, we describe how to: a) design a normative study to gather proper normative sample data; b) select a proper GAMLSS model for an empirical scale; c) derive the desired normed scores for the scale from the fitted model, including those for a composite scale; and d) visualize the results to achieve insight into the properties of the scale. Following these steps yields regression-based norms with GAMLSS for a psychological test, as we illustrate with normative data of the intelligence test IDS-2. The complete R code and data set is provided as supplemental material.

Statistical evaluation and modelling of the stomach contents of Icelandic cod (Gadus morhua)

1997 ◽  
Vol 54 (1) ◽  
pp. 169-181 ◽  
Author(s):  
G Stefansson ◽  
O K Palsson
Keyword(s):  
Degrees Of Freedom ◽  
Gadus Morhua ◽  
Present Model ◽  
Generalized Additive Models ◽  
Stomach Contents ◽  
Additive Models ◽  
Data Set ◽  
Proposed Model ◽  
Sampling Procedures ◽  
Combine Information

A model is proposed for investigating the statistical properties inherent in data on fish stomach contents of cod (Gadus morhua) taken on board Icelandic research vessels. The model explicitly incorporates components to describe the spatial distribution of prey species. It is found that combined delta-gamma (a presence-absence model and an abundance where present model, respectively) generalized additive models are useful in the analysis and explain a considerable portion of the variability in this type of data set, but a fairly large number of degrees of freedom is required to describe the behaviour of the data. A feature of the proposed model is the ability to combine information on the stomach contents from several predator length groups into a single analysis. Analytical results indicate that sampling procedures that base the analysis on the contents of individual stomachs are preferable to those based on combining the contents of several stomachs into aggregate samples.

scholarly journals Exploring the Effect of Conversion on the Distribution of Inflectional Suffixes: A Multivariate Corpus Study

2021 ◽  
Vol 69 (3) ◽  
pp. 267-290
Author(s):  
Alexander Rauhut
Keyword(s):  
English Language ◽  
Generalized Additive Models ◽  
Statistical Modelling ◽  
Additive Models ◽  
Context Dependency ◽  
Word Class ◽  
Corpus Study ◽  
Productive Process ◽  
Lexical Similarity ◽  
Distributional Regression

Abstract Lexical ambiguity in the English language is abundant. Word-class ambiguity is even inherently tied to the productive process of conversion. Most lexemes are rather flexible when it comes to word class, which is facilitated by the minimal morphology that English has preserved. This study takes a multivariate quantitative approach to examine potential patterns that arise in a lexicon where verb-noun and noun-verb conversion are pervasive. The distributions of three inflectional suffixes, verbal -s, nominal -s, and -ed are explored for their interaction with degrees of verb-noun conversion. In order to achieve that, the lexical dispersion, context-dependency, and lexical similarity between the inflected and bare forms were taken into consideration and controlled for in a Generalized Additive Models for Location, Scale and Shape (GAMLSS; Stasinopoulos, M. D., R. A. Rigby, and F. De Bastiani. 2018. “GAMLSS: A Distributional Regression Approach.” Statistical Modelling 18 (3–4): 248–73). The results of a series of zero-one-inflated beta models suggest that there is a clear “uncanny” valley of lexemes that show similar proportions of verbal and nominal uses. Such lexemes have a lower proportion of inflectional uses when textual dispersion and context-dependency are controlled for. Furthermore, as soon as there is some degree of conversion, the probability that a lexeme is always encountered without inflection sharply rises. Disambiguation by means of inflection is unlikely to play a uniform role depending on the inflectional distribution of a lexeme.

How flood risk impacts residential rents and property prices

2018 ◽  
Vol 36 (1) ◽  
pp. 50-67 ◽  
Author(s):  
Jens Hirsch ◽  
Jonas Hahn
Keyword(s):  
Flood Risk ◽  
Generalized Additive Models ◽  
Additive Models ◽  
Data Set ◽  
Content Type ◽  
Real Estate Markets ◽  
Property Price ◽  
The Usa ◽  
Rental Markets ◽  
The Impact

Purpose The purpose of this paper is to quantify the impact of 100-year flood risk on both property rents and values in Germany, exemplified by the market of the historic city of Regensburg, and therefore supports investors in understanding market behavior patterns in both rental and investment context. Design/methodology/approach The authors construct two generalized additive models for rents and purchasing prices with spatial components and under inclusion of both typical property characteristics (as control variables) and a 100-year flood risk parameter in order to estimate its effect on the rents and property price structure. The authors apply the methodology to a four-year data set of more than 16,500 observations. Findings The analysis shows that flood risk is a highly significant parameter when estimating both the rent as well as the sales price model. The authors also find that purchase prices for one square meter of living area are, on average, EUR299 lower if the property is located in the flood risk zone. In addition, also rental markets come with a respective, but rather low, discount. Practical implications The authors provide transparency to investors in terms of the impact that a flood risk location has on property rents as well as purchasing prices. The study supports investors by providing evidence on reaction patterns in German real estate markets and helps quantifying the financial impact that comes with flood risk in Germany. Originality/value This is the first study that aims to empirically test and to quantify the impact of flood risk on property rents and purchasing prices in Germany. Related research has been performed for the USA, Ireland and New Zealand and largely refers to event-driven work or rather conceptual in the context of property valuation.

scholarly journals Does Tokyo Stock Exchange Appreciate Corporate Innovations? Role of Patents’ Quality and Research Productivity.

2020 ◽  
Author(s):  
Kostiantyn Ovsiannikov
Keyword(s):  
Stock Exchange ◽  
Manufacturing Sector ◽  
Dominant Role ◽  
Research Question ◽  
Generalized Additive Models ◽  
Additive Models ◽  
Data Set ◽  
Empirical Measures ◽  
Tokyo Stock Exchange

This paper examines the market perception of corporate innovations in Japan. It follows the research question formulated by Hall, Jaffe, and Trajtenberg (2005): "how does innovative activity translate into market value, and what aspects of the underlying process are captured by the empirical measures available?". The novelty of my study is twofold. First, it embraces the longitudinal innovation- and finance-related corporate records to come up with the largest ever combined data-set for Japan that encompasses 632 companies listed at the Tokyo Stock Exchange over the period of 19 years. Second, in addition to linear regressions, it applies the generalized additive models (GAMs). The latter technique allows for realistically capturing nonlinear patterns present in the data while at the same time retaining predictive features of a model. The main finding of the article is following. Amid the dominant role of research and development (R&D), especially for the Pharmaceutical and Chemical industries, market consistently rewards influential patents in the manufacturing sector.

scholarly journals Spatio-temporal distribution of spinetail devil ray Mobula mobular in the eastern tropical Atlantic Ocean

2020 ◽  
Vol 43 ◽  
pp. 447-460
Author(s):  
N Lezama-Ochoa ◽  
J Lopez ◽  
M Hall ◽  
P Bach ◽  
F Abascal ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Generalized Additive Models ◽  
Temporal Distribution ◽  
Additive Models ◽  
Future Research ◽  
Tropical Atlantic ◽  
Environmental Preferences ◽  
Upwelling System ◽  
The Pacific ◽  
Spatio Temporal

The distribution of the spinetail devil ray Mobula mobular in the eastern tropical Atlantic remains poorly known compared to the Pacific and Indian Oceans. We used fishery-dependent data and generalized additive models to examine the environmental characteristics associated with the presence of M. mobular in the eastern Atlantic Ocean. Results revealed that the distribution of M. mobular is significantly associated with seasonal upwelling systems in coastal and pelagic areas. Our model predicted the presence of the species in areas where there is evidence of its occurrence, such as the Angolan upwelling system and the coast of Ghana. In addition, our model predicted new hotspot areas, including locations around the Mauritanian upwelling system, the Guinea coast, offshore Ghana and the south coast of Angola and Brazil, where sample sizes are limited. Those areas, as well as the environmental preferences depicted by the model, provide valuable information about the habitat and ecology of the spinetail devil ray. Future research lines derived from this study, as well as its limitations, are discussed. Furthermore, in light of our results we discuss the improvements that are needed to contribute to the conservation and management of this vulnerable species.

Fine-scale horizontal distributions of multiple species of larval tuna off the Nansei Islands, Japan

2020 ◽  
Vol 636 ◽  
pp. 123-137 ◽  
Author(s):  
A Tawa ◽  
T Kodama ◽  
K Sakuma ◽  
T Ishihara ◽  
S Ohshimo
Keyword(s):  
Feeding Habits ◽  
Generalized Additive Models ◽  
Kuroshio Current ◽  
Additive Models ◽  
Sea Surface ◽  
Height Anomaly ◽  
Ecological Niches ◽  
Thunnus Orientalis ◽  
Nansei Islands ◽  
The Kuroshio

To quantitatively evaluate the distribution of tuna larvae relative to oceanographic conditions, we conducted investigations off the Nansei Islands in the western North Pacific in June from 2015 to 2017. Five species, namely Pacific bluefin tuna Thunnus orientalis (PBF), yellowfin tuna T. albacares (YFT), skipjack tuna Katsuwonus pelamis (SKJ), frigate tuna Auxis thazard, and bullet tuna A. rochei (BT), were collected in each year. The most dominant species was BT throughout the 3 yr period, followed by SKJ in 2015 and YFT in 2016 and 2017. The horizontal larval distributions of the 5 species were largely influenced by the Kuroshio Current: larvae of the 2 Auxis species were distributed in the Kuroshio and the Kuroshio inshore waters, whereas those of the other species were found in the Kuroshio offshore waters. These differences are consistent with the differences in spawner distributions among the tunas. Generalized additive models (GAMs) indicated that the larval densities were affected by the sea surface height anomaly and that the larvae were not always amassed by horizontal transport. Sea surface temperature (SST) and salinity possibly influenced the larval physiology and survival, thereby determining their densities. In the GAMs, PBF and YFT showed similar responses to SST, and YFT and SKJ similarly responded to salinity. To avoid overlapping their ecological niches, the larvae of 3 species (PBF, YFT, and SKJ) are expected to differ in other ways, including their vertical distributions and feeding habits.

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