Related Reference Points Research Articles

Population biology and stock status of common carp (Cyprinus carpio Linnaeus, 1758) in the Caspian Sea

Common carp Cyprinus carpio Linnaeus, 1758 includes one of the most significant proportions of the Iranian commercial catch in the Caspian Sea (CS). The catch of this endemic species has suffered a high fluctuation over the last decades due to anthropogenic effects and management strategies. Age, growth, natural mortality, and age at first capture were investigated. Also, the stock assessment, fishing mortality (F), exploitation rate (E), and stock management in different strategies were estimated. In the period 1997/98–2021/22, the fork length and weight ranged between 15 and 71 cm and 100–5452 g. This fish showed a hypo-allometric growth pattern in the CS. The calculated growth parameters L∞, K, and t0 were 73.1, 0.125 yr-1, and − 0.91 yr, respectively. The annual population peaked at 35.3 million in 2002/03, then continuously declined until 2012/13, which represented only 1.9% of the peak. Over the period (25 yrs), in 21 yrs the E was more than 0.5, indicating fishing pressure on the C. carpio population in the area. The Fcurrent (0.57 yr-1) was greater than the related reference points of F0.1 (0.28 yr-1) and F30% (0.25 yr-1), indicating overfishing. The current tc was lower than the optimal tc (3.3 yr), indicating a growth overfishing. The current spawning potential ratio SPR (10%) was lower than the optimal value of 30%, indicating recruitment overfishing. It was recommended the F should be reduced half of the Fcurrent to avoid recruitment overfishing. The FL should be limited to 30 cm as minimum legal size of catch to avoid growth overfishing.

Biphasic versus monophasic growth curve equation, an application to common sole (Solea solea, L.) in the northern and central Adriatic Sea

Traditionally, growth patterns are described as constant throughout life using von Bertalanffy's equation. However, a change in growth due to a reallocation of energy during an individual’s lifespan is to be expected. Following this hypothesis, back-calculation measurements obtained from SoleMon survey data were used to fit and compare monophasic and biphasic growth curves for common sole in the northern and central Adriatic Sea. Moreover, individual variability in growth was considered through nonlinear mixed-effect models in which the individual parameters were considered as a random effect. The analyses performed in this study revealed systematic age-specific discrepancies in the monophasic curve and demonstrated that the fit of the biphasic curve was superior (Δ AIC: 329; Δ BIC: 310), confirming the theory that growth in size would decrease as a consequence of reproductive effort. Finally, since common sole is routinely assessed using models that rely on growth to derive assessment estimates and related management reference points, a stock assessment simulation was performed to compare the two growth alternatives. The results showed how the biphasic alternative was preferable to the conventional alternative and how the use of the monophasic pattern would result in an overly optimistic view of stock status (+40% in SSB/SSBtarget and −35% in F/Ftarget compared to the biphasic pattern), thereby increasing the risk of overfishing.

The Reproductive Biology of Female Atlantic Herring in U.S. Waters: Validating Classification Schemes for Assessing the Importance of Spring and Skipped Spawning

AbstractAtlantic Herring Clupea harengus are iteroparous (repeat spawners) with group‐synchronous oocyte development and determinate fecundity, and they are total spawners. However, they also exhibit plasticity in other aspects of their reproductive biology including spawning seasonality and skipped spawning. Previous studies in other regions have reported skipped spawning and errors in macroscopic classifications of maturity, both of which could bias estimates of reproductive potential, but a critical assessment of these in U.S. waters is lacking. In the Gulf of Maine and Georges Bank, herring are assessed as a single stock complex, where females typically mature as 3 to 4 year olds and may live up to 11 years. To evaluate the magnitude of skipped spawning, we collected the ovaries of Atlantic Herring from fishery‐dependent and fishery‐independent sources over multiple seasons and evaluated them histologically to assess imminent (indicated by vitellogenic or maturing oocytes) or recent spawning (evidenced by the presence of postovulatory follicles). Gonad histology allowed us to determine spawning seasonality and skipped spawning. Macroscopic maturity classification was more accurate in fall (1–4% incorrect maturity) than in spring (7% incorrect maturity). The spatial distributions of immature and mature fish from both fishery‐dependent and fishery‐independent sources differed, which affected the estimation of maturity at length and age. We estimated 9–14% spring spawners in the region, but we did not find evidence of skipped spawning. The time series of the macroscopic data that were available (1987–2018) showed increases in spring spawning with latitude, but the proportions have not changed much over recent decades. The effects of up to 30% spring or skipped spawning on a stock assessment of Atlantic Herring were evaluated. Spring spawning had little effect relative to assuming 100% fall spawning (the current assumption), and skipped spawning decreased the scale of spawning stock biomass (SSB) and related reference points, with the degree of change increasing with skipped spawning rates, but it had few consequences otherwise.

Misspecification in stock assessments: Common uncertainties and asymmetric risks

AbstractCommon uncertainties in stock assessment relate to parameters or assumptions that strongly determine both the estimates of quantities of management interest (e.g. stock depletion) and related reference points (e.g. biomass at maximum sustainable yield). The risks associated with these uncertainties are often presented to managers in the form of decision tables. However, a formal evaluation of the risks from misspecifying an assessment model over time‐horizons spanning multiple assessment cycles requires closed‐loop simulation. There were two aims of this study: (a) develop an approach to identify and evaluate asymmetries in risk to yields and spawning biomass due to biases in key parameters and data sources in a stock assessment model, (b) quantify the relative importance of correctly specifying the various assessment attributes. A computationally efficient stock reduction analysis was evaluated using closed‐loop simulation to identify risks associated with a stock assessment with persistent positive and negative biases in the key parameters and inaccurate assumptions regarding data sources. Six types of assessment misspecification were examined, namely the assumed natural mortality rate, the assumed recruitment compensation ratio, the assumed age of maturity, a hyper‐stable or hyper‐deplete index of abundance, over‐ or under‐reporting of historical catch, and misspecification of the assumed shape of the selectivity curve. This study reveals large asymmetries in risk associated with common uncertainties in stock assessment processes. We highlight the value of reproducible and computationally efficient stock assessment models that can be investigated by closed‐loop simulation before being used for fisheries management.

The inflection point: a torque reference for lingual bracket positioning on the palatal surface curvature of the maxillary central incisor

BackgroundContrary to buccal orthodontics, lingual orthodontics has no reference for vertical bracket positioning on the maxillary central incisor. The aim of this study was to provide a reference point in relation to torque for lingual bracket positioning on the palatal surface curvature (PSC) of the maxillary central incisor.MethodsCone beam computed tomography (CBCT) radiographs of 50 right maxillary central incisors from archives of a dental radiographic center were transferred to Photoshop, where their PSC was traced using pen-tool. The PSC torque angle values of the incisors were calculated in Excel using cubic poly-Bezier curves at 0.5-mm increments and at the inflection point of PSC. Descriptive statistics for the torque angle values of the increments and for the inflection point for the 50 incisors were then calculated. One-way ANOVA test was used to detect systematic differences between the increments, and Tukey test was used post-hoc.ResultsFor all incisors, increments incisal to inflection point exhibited progressive decrease in torque angle values from the first-calculated increment to inflection point while increments cervical to inflection point exhibited progressive increase from inflection point to last-calculated increment. Mean torque angle values of all the increments and inflection point showed high standard deviations and vast range of values. One-way ANOVA test was highly statistically significant (p < 0.0001) and most pairwise comparisons of the increments using Tukey test were significant.ConclusionsInflection point can be used as a reference for bracket positioning on PSC. Cervically oriented shifts in vertical bracket position cause crown labial/root palatal movement cervical to inflection point and crown palatal/root labial movement incisal to it. A scientific mathematical justification for customized bracket torque prescriptions on PSC of maxillary central incisor was also provided.

When Richard met CG: reference-point and English copy-raising

abstractThe aim of this paper is to develop a Cognitive Grammar-based analysis of English Copy-raising (CR) constructions such asRichard seems like he is dancing. We argue that the notion of reference-point plays a crucial role in licensing the matrix-subject of the construction. In CR, with the epistemic verbsseemandappear, the matrix-subject functions as a reference-point in relation to the pronominal copy (if a copy exists) in the embedded clause. The aboutness topicality of the matrix-subject in CR is expected, owing to its reference-point property. The epistemic CR construction is acceptable without a pronominal copy if the matrix-subject functions as a reference-point in relation to the complement clause. The same type of analysis is applied to the CR construction with perceptual resemblance (PR) verbs –sound,look,feel, andsmell– leading to the conclusion that the strong dichotomy between epistemic and PR verbs is illusory. It is further demonstrated that expletivethere-raising in CR is motivated by the same reference-point phenomenon. The difference betweenthere-raising and other CR examples stems from the role ofthereas a setting subject. Our reference-point-based analysis predicts a metonymic interpretation of the matrix-subject, which we attribute to the connection between reference-point and metonymy.

Robert Nisbet and the Present Age

Among well-known sociologists, Robert Nisbet was almost unique in considering himself a “conservative.” He defined this orientation not in terms of conventional American partisan affiliation but as a sociological and anthropological perspective. Nisbet viewed human relations as requiring organic relations, which he assumed to be hierarchical and communally determined. Such relations seemed to Nisbet natural and even beneficial; and his lifelong interest in nineteenth-century social theory and his efforts to locate organicist positions among social thinkers of the Left, especially Emile Durkheim, can be attributed to an attempt to substantiate his understanding of basic human relations. Nisbet also significantly viewed contemporary America as departing rapidly and perhaps irreversibly from what he considered to be a good society. This concern pervades his studies of social theory; and it is possible to interpret his emphasis on the “conservative” origins of sociology and his attack on leveling public administration from the 1950s onward as related reference points. Against the social disintegration and social engineering that he already criticizes in his early work The Quest for Community, Nisbet (1990) poses his vision of personal authority and communal hierarchy. This vision is present in Nisbet’s writings, from his early studies of French counterrevolutionary thinkers through his final assaults on America in the present age.

Insecure lives: questioning ‘The Precariat’

In this edition of cjm we examine precarious living in modern conditions. Guy Standing's work on The Precariat provides a reference point in relation to this theme. Standing's book is subtitled ‘the new dangerous class’: this immediately pitches the idea into a maelstrom of inter-disciplinary concerns. Historically, notions of the ‘dangerous class’ take us straight back to the seething combinations of criminality, pauperism and vice in the nineteenth century and the worlds that modernity, democracy and the welfare state had presumed to have left behind. Culturally, the idea brings to mind the supposedly demoralised ‘underclass’; their feckless offspring, the needy and the risky, of welfare citizenship and an indulgent nanny state. Sociologically, this dangerous class poses questions about inequalities, divisions, social exclusion and the forms of advanced marginality becoming characteristic of late modernity. Politically, the idea raises the spectre of a revolutionary vanguard, of militant resistance, protesters, rioters or ‘enemies within’ and, drawing these ideas together, where marginality manifests itself as ‘radicalisation’, of ‘suspect communities’, threat profiles, aliens and enemies. It follows that, above all, ‘The Precariat’ is a fertile ground for criminology.

Metonymy in grammar

This article focuses on the conceptual structures of Korean Multiple Object Constructions (MOCs), which exhibit various types of meanings. I argue that these various meanings are systematically explained when we adopt the notion of reference point. I claim that the accusative-marked nominals in the constructions are metonymically connected; outer accusative-marked nominals function as reference points. More specifically, NP1, in the schematic configuration [NP-Nom [NP1-Acc [NP2-Acc [PRED]]]], functions as a reference point in relation to the complex verb [NP2-PRED], where NP1 provides access to the target. In other words, the function of Korean MOCs is to provide mental access to a target, similar to English possessive constructions. For example, since one natural mental path of access is by following a taxonomic hierarchy from general to specific, the metonymic meaning of the Type-Token construction arises. The same mechanism is then recursively applied to explain the case of multiply-occurring accusative-marked nominals. In order to provide technical analyses of my claim, Langacker’s Cognitive Grammar is adopted as a theoretical framework as it accurately captures the properties of the constructions without additional unnecessary mechanisms.

Implications of uncertainty in the spawner–recruitment relationship for fisheries management: An illustration using bigeye tuna (Thunnus obesus) in the eastern Pacific Ocean

The impacts of the steepness parameter of the Beverton–Holt spawner–recruitment curve on fisheries stock assessment and management performance were evaluated, using data for bigeye tuna (Thunnus obesus) in the eastern Pacific Ocean. The analysis was conducted using the Stock Synthesis model. The estimates of maximum sustainable yield (MSY) and related management reference points are sensitive to the value of steepness (ranging from 0.4 to 1.0) of the Beverton–Holt spawner–recruitment relationship assumed in the assessment model. Steepness also impacts the evaluation of stock status. A lesser value assumed for steepness leads to a more pessimistic evaluation of the stock status regarding whether the stock is overfished or overfishing is occurring. However, a lesser value does not reduce the estimates of MSY due to the interaction between steepness and the estimates of other model parameters. When managing the stock under effort limitation using MSY-based fishing mortality, a lower assumption of steepness yields less expected losses in catch than does a higher assumption. This is due to the flatness of the yield curve when the steepness is high. A lower assumption of steepness also maintains a higher level of spawning biomass and recruitment.

Registration Based on Projective Reconstruction Technique for Augmented Reality Systems

In AR systems, registration is one of the most difficult problems currently limiting their application. In this paper, we propose a simple registration method using projective reconstruction. This method consists of two steps: embedding and tracking. Embedding involves specifying four points to build the world coordinate system on which a virtual object will be superimposed. In tracking, a projective reconstruction technique is used to track these four specified points to compute the model view transformation for augmentation. This method is simple, as only four points need to be specified at the embedding stage and the virtual object can then be easily augmented onto a real scene from a video sequence. In addition, it can be extended to a scenario using the projective matrix that has been obtained from previous registration results using the same AR system. The proposed method has three advantages: 1) It is fast because the linear least square method can be used to estimate the related matrix in the algorithm and it is not necessary to calculate the fundamental matrix in the extended case. 2) A virtual object can still be superimposed on a related area even if some parts of the specified area are occluded during the whole process. 3) This method is robust because it remains effective even when not all the reference points are detected during the whole process, as long as at least six pairs of related reference points correspondences can be found. Some experiments have been conducted to validate the performance of the proposed method.

Application of pre-fishery abundance modelling and Bayesian hierarchical stock and recruitment analysis to the provision of precautionary catch advice for Irish salmon (Salmo salar L.) fisheries

Abstract Ireland has one of the last remaining commercial salmon driftnet fisheries in the North Atlantic, with recent catches averaging 162 000 salmon (1997–2003), approximately 20% of the total landings of salmon in the entire North Atlantic. Since 2001, the Irish commercial salmon fishery has been managed on the basis of Total Allowable Catch (TAC) in each of 17 salmon fishing districts. This has been made possible by applying a number of new and innovative techniques to the estimation of conservation limits (CLs) and pre-fishery abundance (PFA) for combined stocks in each district. Stock and recruitment parameters from well-monitored European rivers were “transported” to all Irish rivers using a Bayesian hierarchical stock and recruitment (BHSRA) model. This provided the posterior probability distributions of the model parameters and related reference points, including individual river CLs. District PFA and the number of spawners were estimated for a baseline period of 1997–2003, using district catch data, estimates of unreported catch, and exploitation rate. Harvest guidelines were established on the basis of surplus of spawning fish over the CL for the baseline period. In line with scientific advice, the commercial fishery has been reduced from 212 000 fish in 2002 to 182 000 in 2003. In 2004, a total catch (including the rod catch) of approximately 160 000 wild salmon was advised.

Stock-recruitment relationships and the precautionary approach to management of tropical shrimp fisheries

This paper examines the possibilities and implications of using precautionary management approaches to deal with the uncertainty regarding the stock-recruitment relationships in tropical shrimp fisheries. After a brief review of the stock-recruitment problem and related reference points in these fisheries, and in the precautionary approach in general, it proposes an empirical approach to the stock-recruitment relationship as a basis for the determination of safe and risky fishing mortality levels. It illustrates a management strategy based on the seasonal escapement of spawning biomass. Finally, it offers a discussion on the robustness of the empirical approach and on its validation using additional information.

Position of the apex beat in childhood.

The position of the apex beat in relation to the midclavicular and nipples lines and the intercostal spaces was studied in 353 healthy Jamaican children from birth to 10 years. The traditional use of the midclavicular line as a reference point in relation to the apex beat is not an accurate index of normal heart size at all ages. For this purpose actual measurement of the apex beat, which ranges between 2.8 and and 5.4 cm from the midline, should be made. However, for a rough estimate of normal cardiac size the midclavicular line may be used. In contrast, the nipple line lies outside the apex beat at all ages; it should not be used in the clinical evaluation of normal cardiac size. From birth to age 3 years the apex beat is located in the 4th intercostal space and with increasing age gradually moves into the 5th space in most children.