The phylogeny of the stomatopod Crustacea

2000 ◽  
Vol 48 (6) ◽  
pp. 607 ◽  
Author(s):  
Shane T. Ahyong ◽  
Christine Harling
Keyword(s):  
Missing Data ◽  
Cladistic Analysis ◽  
The Other ◽  
Crown Group ◽  
Data Set ◽  
Long Line ◽  
Stem Lineage ◽  
The Impact ◽  
Hard Substrates ◽  
Familial Classification

The stomatopods, or mantis shrimps, are malacostracan crustaceans of the subclass Hoplocarida. Extant hoplocarids belong to the order Stomatopoda and suborder Unipeltata, comprising the extinct, stem-lineage pseudosculdids and sculdids, and the crown group. Cladistic analysis including most or all genera of the unipeltatan families, and rooted to the extinct Tyrannophontidae, resulted in four most-parsimonious cladograms. The present results are more highly resolved and more robust than previous studies as the result of: more precise identification of suitable outgroups; a more complete outgroup data set, lessening the impact of missing data; and increased taxonomic sampling. The results largely support the existing five-superfamily classification, but as with two recent cladistic studies, Gonodactyloidea was polyphyletic. Gonodactyloidea is the basal crown-group superfamily and comprises mostly ‘smashers’. Two clades of ‘spearers’, Eurysquillidae and Parasquillidae, previously considered gonodactyloids, are more closely related to the Squilloidea and are referred to new superfamilies. The familial classification within Lysiosquilloidea is modified. Rather than deriving the ‘smashers’ from a long line of ‘spearers’, the present analysis suggests that the Unipeltata diverged in two broad directions from the outset. Hence, the gonodactyloid ‘smashers’ became specialised for hard substrates, and the remainder diversified into the other modern superfamilies, evolving more efficient ‘spearing’ claws, and occupying soft substrates.

scholarly journals Maximum Likelihood Estimation of the VAR(1) Model Parameters with Missing Observations

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Helena Mouriño ◽  
Maria Isabel Barão
Keyword(s):  
Stochastic Process ◽  
Missing Data ◽  
Maximum Likelihood ◽  
Moving Average ◽  
Practical Importance ◽  
Likelihood Estimation ◽  
Model Parameters ◽  
Missing Observations ◽  
Data Set ◽  
The Impact

Missing-data problems are extremely common in practice. To achieve reliable inferential results, we need to take into account this feature of the data. Suppose that the univariate data set under analysis has missing observations. This paper examines the impact of selecting an auxiliary complete data set—whose underlying stochastic process is to some extent interdependent with the former—to improve the efficiency of the estimators for the relevant parameters of the model. The Vector AutoRegressive (VAR) Model has revealed to be an extremely useful tool in capturing the dynamics of bivariate time series. We propose maximum likelihood estimators for the parameters of the VAR(1) Model based on monotone missing data pattern. Estimators’ precision is also derived. Afterwards, we compare the bivariate modelling scheme with its univariate counterpart. More precisely, the univariate data set with missing observations will be modelled by an AutoRegressive Moving Average (ARMA(2,1)) Model. We will also analyse the behaviour of the AutoRegressive Model of order one, AR(1), due to its practical importance. We focus on the mean value of the main stochastic process. By simulation studies, we conclude that the estimator based on the VAR(1) Model is preferable to those derived from the univariate context.

Can BRICS and ASEAN-5 emerging economies benefit from bank diversification?

2019 ◽  
Vol 27 (1) ◽  
pp. 43-69 ◽  
Author(s):  
Syed Moudud-Ul-Huq
Keyword(s):  
Risk Taking ◽  
Generalized Method Of Moments ◽  
The Other ◽  
Set Covering ◽  
Diversification Strategy ◽  
Data Set ◽  
Content Type ◽  
Diversification Benefit ◽  
The Impact ◽  
The Relationship

Purpose This paper aims to empirically investigate the impact of bank diversification on performance and risk-taking behavior. The analysis uses an unbalanced panel data set covering the period between 2007 and 2015 for a total of 1,397 banks from ASEAN-5 and BRICS economies. Design/methodology/approach Dynamic panel generalized method of moments (GMM) has been used primarily to examine the relationship between bank diversification on performance and risk-taking and later, validate the core results by incorporating two-stage least squares (2SLS). Findings Similar to the results of previous studies based on the developed economy, this study also confirms the hypothesis of the portfolio diversification. The key robust result is that the benefits from revenue and assets diversification are heterogeneous and the BRICS banks achieve higher benefit from using both diversification strategies. On the other hand, ASEAN-5 banks fail to show the significant advantage from assets diversification. Among the diverse sources of income, interest is not a major determinant of efficiency and bank’s stability, while ASEAN-5 banks should foster commission and others income as mechanisms for diversification benefit in the region. Originality/value A few studies are available in the current literature which examines the impact of revenue and assets diversification on either bank performance or risk-taking in the developed economy’s context. However, very few studies are found that examine the relationship between bank diversification, performance and risk-taking together. Moreover, to the best of the author’s knowledge, there is a dearth of literature on this topic that built on the comparative analysis between two regions, i.e. ASEAN-5 and BRICS. As a result, the empirical results of this research provide useful information to the stakeholders so that they can enhance bank diversification strategy and implement them successfully by considering the other factors.

scholarly journals DO PUBLIC AND PRIVATE DEBT LEVELS AFFECT THE SIZE OF FISCAL MULTIPLIERS?

2017 ◽  
Vol 32 (3) ◽  
pp. 209
Author(s):  
Chairul Adi
Keyword(s):  
Public Investment ◽  
The Other ◽  
Public Expenditures ◽  
Fiscal Policies ◽  
Data Set ◽  
Private Debt ◽  
Public And Private ◽  
Economic Output ◽  
Other Hand ◽  
The Impact

This paper investigates the effectiveness of fiscal policies – as measured by the impact and cumulative multipliers – and how they interact with public and private debt. Harnessing the moderated panel regression approach, based on the yearly data set of several economies during the period from 1996 to 2012, the analysis is focused on the impact of spending-and-revenue-based fiscal policies on economic growth and how these fiscal instruments interact with public and private indebtedness. The result of spending stimuli advocates the basic Keynesian theory. An increase in public expenditures contemporaneously generates a positive multiplier, of around 0.29 – 0.44 and around 0.45 – 0.58 during two years. Decomposing the expenditures into their elements, this paper documents a stronger impact from public investment than that from government purchases. On the other hand, the revenue stimuli seem to follow the Ricardian Equivalence Hypothesis (REH), arguing that current tax cuts are inconsequential. The impact and cumulative multipliers for this fiscal instrument have mixed results, ranging from -0.21 to 0.05 and -0.26 to 0.06, respectively. Moreover, no robust evidence is found to support the argument that government debt moderates the effectiveness of fiscal policies. The size of the multipliers for both spending and revenue policies remain constant with the level of public debt. On the other hand, private debt appears to show a statistically significant moderating effect on spending stimuli. Its impact on spending multipliers, however, is economically insignificant. The moderation effect of private debt on the revenue stimuli does not seem to exist. Finally, this paper documents that both public and private debt exhibit a negative and statistically significant estimation for economic output.

scholarly journals Overcoming challenges to data quality in the ASPREE clinical trial

Trials ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jessica E. Lockery ◽  
◽  
Taya A. Collyer ◽  
Christopher M. Reid ◽  
Michael E. Ernst ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Missing Data ◽  
Data Quality ◽  
Large Scale ◽  
Controlled Trial ◽  
Data Entry ◽  
Quality Data ◽  
Community Based ◽  
Data Set ◽  
The Impact

Abstract Background Large-scale studies risk generating inaccurate and missing data due to the complexity of data collection. Technology has the potential to improve data quality by providing operational support to data collectors. However, this potential is under-explored in community-based trials. The Aspirin in reducing events in the elderly (ASPREE) trial developed a data suite that was specifically designed to support data collectors: the ASPREE Web Accessible Relational Database (AWARD). This paper describes AWARD and the impact of system design on data quality. Methods AWARD’s operational requirements, conceptual design, key challenges and design solutions for data quality are presented. Impact of design features is assessed through comparison of baseline data collected prior to implementation of key functionality (n = 1000) with data collected post implementation (n = 18,114). Overall data quality is assessed according to data category. Results At baseline, implementation of user-driven functionality reduced staff error (from 0.3% to 0.01%), out-of-range data entry (from 0.14% to 0.04%) and protocol deviations (from 0.4% to 0.08%). In the longitudinal data set, which contained more than 39 million data values collected within AWARD, 96.6% of data values were entered within specified query range or found to be accurate upon querying. The remaining data were missing (3.4%). Participant non-attendance at scheduled study activity was the most common cause of missing data. Costs associated with cleaning data in ASPREE were lower than expected compared with reports from other trials. Conclusions Clinical trials undertake complex operational activity in order to collect data, but technology rarely provides sufficient support. We find the AWARD suite provides proof of principle that designing technology to support data collectors can mitigate known causes of poor data quality and produce higher-quality data. Health information technology (IT) products that support the conduct of scheduled activity in addition to traditional data entry will enhance community-based clinical trials. A standardised framework for reporting data quality would aid comparisons across clinical trials. Trial registration International Standard Randomized Controlled Trial Number Register, ISRCTN83772183. Registered on 3 March 2005.

A phylogenetic analysis of the isopod family Janiridae (Crustacea)

1994 ◽  
Vol 8 (3) ◽  
pp. 749 ◽  
Author(s):  
GDF Wilson
Keyword(s):  
Heuristic Search ◽  
Cladistic Analysis ◽  
Tail Probability ◽  
Search Algorithms ◽  
Data Matrix ◽  
Data Set ◽  
New Family ◽  
Heuristic Search Algorithms ◽  
Family Level ◽  
The Impact

A phylogeny of the isopod family Janiridae and genera from presumptive outgroups, Acanthaspidiidae, Joeropsididae and Microparasellidae is estimated. Characters were gathered from the published literature, and assembled into a data matrix for cladistic analysis. The data, when evaluated with heuristic search algorithms, yielded eight most-parsimonious trees, none of which supported the monophyly of the Janiridae. To evaluate the impact of homoplasy, characters with a rescaled consistency less than 0.1 were deleted, resulting in four somewhat different trees that were non-monophyletic for the janirids. With the smaller data set, trees supporting janirid monophyly were 10 steps longer. A permutation tail probability test found substantially more hierarchical information in the janirid data set than in randomised data. Internal topologies of the shortest trees were evaluated as hypotheses for new family-level groups, although new family-level classifications cannot be proposed at this time owing to insufficient evidence. The Janiridae therefore cannot be considered monophyletic.

International Swimming League: Do Successive Events Lead to Improve Swimming Performance?

2021 ◽  
pp. 1-4
Author(s):  
Robin Pla ◽  
Arthur Leroy ◽  
Yannis Raineteau ◽  
Philippe Hellard
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Swimming Performance ◽  
Support Staff ◽  
The Other ◽  
Data Set ◽  
Age And Gender ◽  
World Class ◽  
And Gender ◽  
The Impact

Purpose: To quantify the impact of successive competitions on swimming performance in world-class swimmers. Methods: An entire data set of all events swum during a new competition named the International Swimming League was collected. A Bayesian linear mixed model has been proposed to evaluate whether a progression could be observed during the International Swimming League’s successive competitions and to quantify this effect according to event, age, and gender. Results: An overall progression of 0.0005 (0.0001 to 0.0010) m/s/d was observed. The daily mean progression (ie, faster performance) was twice as high for men as for women (0.0008 [0.00 to 0.0014] vs 0.0003 [−0.0003 to 0.0009] m·s−1). A tendency toward higher progression for middle distances (200 and 400 m) and for swimmers of a higher caliber (above 850 FINA [Fédération Internationale de Natation] points) was also observed. Swimmers between 23 and 26 years of age seemed to improve their swimming speed more in comparison with the other swimmers. Conclusions: This new league format, which involves several competitions in a row, seems to allow for an enhancement in swimming performance. Coaches and their support staff can now adapt their periodization plan in order to promote competition participation.

On the Competitive and Collaborative Implications of Category Captainship

2017 ◽  
Vol 81 (4) ◽  
pp. 127-143 ◽  
Author(s):  
Yasin Alan ◽  
Jeffrey P. Dotson ◽  
Mümin Kurtuluş
Keyword(s):  
Management Strategy ◽  
Product Category ◽  
Theoretical Models ◽  
The Other ◽  
Private Label ◽  
Data Set ◽  
Unique Data ◽  
Category Captainship ◽  
Joint Consideration ◽  
The Impact

Category captainship (CC) is a retailing practice wherein a retailer collaborates with one of the manufacturers in a product category (referred to as the captain) to develop and implement a category management strategy. Although CC has been studied using both theoretical models and surveys, empirical evidence on the benefits and drawbacks of CC is scarce. The authors use a unique data set collected during a CC implementation to empirically examine the impact of CC on the retailer, the captain, and the other manufacturers in the category. The authors find that both the retailer's private label and the captain benefit from CC because of pricing and assortment changes. They also find that some competing manufacturers benefit from CC while others suffer. Specifically, the manufacturers that closely compete with the captain benefit, whereas the manufacturers that are in close competition with the private label suffer because the retailer protects its private label. The authors show that category sales would have been higher if the retailer had not protected its private label. This study sheds light on how joint consideration of assortment and pricing, the presence of a private label, and product characteristics may influence the outcomes of CC implementations.

Multi-Segmented Arthropods from the Middle Cambrian of British Columbia (Canada)

2013 ◽  
Vol 87 (3) ◽  
pp. 493-501 ◽  
Author(s):  
David Legg
Keyword(s):  
British Columbia ◽  
National Park ◽  
Cladistic Analysis ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Crown Group ◽  
Middle Cambrian ◽  
New Family ◽  
Stem Lineage ◽  
Shale Formation

A new arthropod, Kootenichela deppi n. gen. n. sp., is described from the Stanley Glacier exposure of the middle Cambrian (Series 3, Stage 5) Stephen Formation in Kootenay National Park (British Columbia, Canada). This taxon possesses a number of primitive arthropod features such as an elongate, homonomous trunk (consisting of at least 29 segments), poorly sclerotised trunk appendages, and large pedunculate eyes associated with an anterior (ocular) sclerite. The cephalon encompasses a possible antenna-like appendage and enlarged raptorial appendages with a bipartite peduncle and three spinose distal podomeres, indicative of megacheiran (“great-appendage” arthropod) affinities. The relationships of megacheirans are controversial, with them generally considered as either stem-euarthropods or a paraphyletic stem-lineage of chelicerates. An extensive cladistic analysis resolved Kootenichela as sister-taxon to the enigmatic Worthenella cambria from the middle Cambrian (Series 3, Stage 5), Burgess Shale Formation in Yoho National Park (British Columbia), which is herein reinterpreted as a megacheiran arthropod. Based on their sister-group relationship, both taxa were placed in the new family Kootenichelidae, to which Pseudoiulia from the Chengjiang biota is also tentatively assigned. All of these taxa possess an elongate, multi-segmented body and subtriangular exopods. This family occupies a basal position within a paraphyletic Megacheira, the immediate outgroup of Euarthropoda (crown-group arthropods). The resultant topology indicates that analyses that have resolved megacheirans as stem-chelicerates have done so because they have rooted on inappropriate taxa, e.g., trilobitomorphs and marrellomorphs.

Phylogenetic analysis of the Squilloidea (Crustacea:Stomatopoda)

2005 ◽  
Vol 19 (3) ◽  
pp. 189 ◽  
Author(s):  
Shane T. Ahyong
Keyword(s):  
Phylogenetic Analysis ◽  
Late Cretaceous ◽  
Cladistic Analysis ◽  
West Pacific ◽  
East Pacific ◽  
Stem Lineage ◽  
Familial Classification

Squilloidea is the most speciose of the stomatopod superfamilies and comprises more than 40 genera. Until 2001, three families were recognised: two extant (Harpiosquillidae, Squillidae) and one extinct (Ursquillidae). Recent studies, however, suggested that Harpiosquillidae is nested among other squillids and was thus synonymised with Squillidae. Interrelationships of all squilloid genera are studied by cladistic analysis based on somatic morphology. Results are used to assess the familial classification and investigate the ‘shape’ of squilloid evolution. The phylogeny of the squilloids shows general trends in the armature of the raptorial claw, increased dorsal carination, a tendency for bilobation of the lateral processes of the exposed thoracic somites, and a change in telson shape from trianguloid with movable submedian teeth, to quadriform with fixed submedian teeth. Harpiosquilla Holthuis, 1964 is deeply nested among other squillid genera, supporting the recent synonymy of the Squillidae and Harpiosquillidae. Characters of the late Cretaceous Ursquillidae show that it is highly derived and is therefore synonymised with Squillidae. Although the antiquity of Ursquilla Hof, 1998 does not show it to be a basal or stem-lineage squilloid, it does show that the squilloids had already undergone significant diversification by the end of the Cretaceous. Species of most squilloid genera are regionally restricted, either to the Indo-west Pacific or Atlanto-east Pacific. Only Alima Leach, 1818, Cloridopsis Manning 1968b, and Pontiosquilla Manning, 1995 are represented in both regions.

Age at Exposure to Parental Suicide and the Subsequent Risk of Suicide in Young People

Crisis ◽  
2018 ◽  
Vol 39 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Kuan-Ying Lee ◽  
Chung-Yi Li ◽  
Kun-Chia Chang ◽  
Tsung-Hsueh Lu ◽  
Ying-Yeh Chen
Keyword(s):  
Young People ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Birth Registry ◽  
Data Set ◽  
Parental Suicide ◽  
The Impact ◽  
Age At Exposure

Abstract. Background: We investigated the age at exposure to parental suicide and the risk of subsequent suicide completion in young people. The impact of parental and offspring sex was also examined. Method: Using a cohort study design, we linked Taiwan's Birth Registry (1978–1997) with Taiwan's Death Registry (1985–2009) and identified 40,249 children who had experienced maternal suicide (n = 14,431), paternal suicide (n = 26,887), or the suicide of both parents (n = 281). Each exposed child was matched to 10 children of the same sex and birth year whose parents were still alive. This yielded a total of 398,081 children for our non-exposed cohort. A Cox proportional hazards model was used to compare the suicide risk of the exposed and non-exposed groups. Results: Compared with the non-exposed group, offspring who were exposed to parental suicide were 3.91 times (95% confidence interval [CI] = 3.10–4.92 more likely to die by suicide after adjusting for baseline characteristics. The risk of suicide seemed to be lower in older male offspring (HR = 3.94, 95% CI = 2.57–6.06), but higher in older female offspring (HR = 5.30, 95% CI = 3.05–9.22). Stratified analyses based on parental sex revealed similar patterns as the combined analysis. Limitations: As only register-­based data were used, we were not able to explore the impact of variables not contained in the data set, such as the role of mental illness. Conclusion: Our findings suggest a prominent elevation in the risk of suicide among offspring who lost their parents to suicide. The risk elevation differed according to the sex of the afflicted offspring as well as to their age at exposure.

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