A peaked logistic-based selection curve

2014 ◽  
Vol 71 (3) ◽  
pp. 351-355 ◽  
Author(s):  
James A. Smith ◽  
Matthew D. Taylor
Keyword(s):  
Large Range ◽  
Logistic Distribution ◽  
Fishing Gear ◽  
Normal Curve ◽  
Logistic Curve ◽  
Size Classes ◽  
Logistic Equations ◽  
Selection For

Length-based selection curves define the relative catchability of fish to specific types of fishing gear, with catchability often highest at intermediate fish lengths. Distributions such as the normal, lognormal, or gamma are often used to define “peaked” selection curves, but these have limited capabilities to describe strongly asymmetric selection relationships, such as those sometimes observed for hooks or gillnets. Another, more flexible, peaked selection curve is proposed, which is derived by combining multiple logistic distributions. While the logistic distribution is frequently used to describe monotonic selection curves, incorporating multiple logistic equations (that describe either the increasing or decreasing catchability) can define a large range of asymmetric peaked selection curves. This “peak-logistic” curve also allows nonzero asymptotic selection for the largest size classes, which may be the selection occurring in some hook-and-line fisheries. We demonstrate examples of selection in hook, haul net, and mixed hook fisheries, for which the peak-logistic curve is more appropriate than comparative lognormal and binormal selection curves. We also promote an alternative to the peak-logistic: the two-sided normal curve.

scholarly journals SELEKTIVITAS KISI-KISI JUVENILE AND TRASH EXCLUDER DEVICES PADAALAT TANGKAP TRAWL MINI DI PERAIRAN UTARA JAWA

2017 ◽  
Vol 14 (4) ◽  
pp. 353
Author(s):  
Hufiadi Hufiadi ◽  
Mahiswara Mahiswara ◽  
Erfind Nurdin
Keyword(s):  
Demersal Fish ◽  
Fishing Gear ◽  
Logistic Curve ◽  
Microsoft Excel ◽  
Fish Resources ◽  
Trash Fish

Perikanan trawl mini dasar yang berkembang merupakan alat tangkap yang efektif dalam memanfaatkan sumber daya ikan demersal. Permasalahan utama pada perikanan ini banyak jumlah hasil tangkap sampingan berukuran kecil yang belum layak tangkap. Penelitian observasi dan uji coba operasi penangkapan untuk mengetahui tipe perikanan trawl mini dan upaya untuk mengurangi tangkapan ikan muda telah dilakukan di perairan utara Jawa. Uji coba operasi penangkapan dilakukan melalui penggunaan perangkat juvenile and trash excluder devices pada alat tangkap trawl mini. Perangkat juvenile and trash excluder devices yang digunakan dibedakan pada ukuran jarak antar kisi-kisi 10,0; 17,5; dan 25,4 mm. Analisis selektivitas kisi menggunakan model kurva logistik dengan bantuan solver pada microsoft excel. Hasil penelitian menunjukkan penggunaan juvenile and trash excluder devices pada trawl mini dapat meloloskan ikan muda atau ukuran kecil berkisar 2,42 sampai dengan 63,45%. Juvenile and trash excluder devices dengan ukuran kisi-kisi 17,5 mm memiliki tingkat pelolosan ikan-ikan muda atau rucah paling efektif pada tingkat seleksi 50% (FL50%). Mini bottom trawls are effective fishing gear to exploit demersal fish resources. However, the gears operation have serious problem on amount of bycatch caught especially for juvenile and trash fish. Observation and experimental fishing were conducted to know type of mini bottom trawls in northern Java waters and to reduce catches of juvenile and trash fish. Juvenile and trash excluder devices are a selective device that equipped on mini trawl in the experimental fishing with different space bar of the juvenile and trash excluder devices (i.e.10.0; 17.5; and 25.4 mm). The selectivity analysis of logistic curve by using solver on microsoft excel was applied. The results show that juvenile and trash excluder devices could reduced catches of juvenile and trash fish about 2.42 to 63.45%. Juvenile and trash excluder devices with 17.5 mm of the space bar was better for juvenile selection length of 50% (FL50%) selection level.

Model selection for determining the growth of juveniles and sub-adults of two species of shrimp (Decapoda, Penaeidae) in a tropical coastal lagoon

Crustaceana ◽  
2016 ◽  
Vol 89 (1) ◽  
pp. 29-45 ◽  
Author(s):  
Karina Monsreal-Vela ◽  
Iván Velázquez-Abunader ◽  
Gaspar R. Poot-López
Keyword(s):  
Coastal Lagoon ◽  
Growth Models ◽  
Growth Curves ◽  
Fishing Gear ◽  
Allometric Growth ◽  
Farfantepenaeus Duorarum ◽  
Selection For ◽  
Relationship Of ◽  
Best Fit ◽  
Seasonal Oscillations

To select the model that allows the growth curves of juvenile and sub-adult shrimp to be described more accurately, a study was carried out in a coastal lagoon in the south of the Gulf of Mexico on the speciesFarfantepenaeus brasiliensis(Latreille, 1817) andFarfantepenaeus duorarum(Burkenroad, 1939). The data were obtained from 11 monthly samplings, taken between April 2011 and February 2012, applying the catch strategies used by the local fishermen, including the fishing gear used. The carapace length (CL)-total weight (TW) relationship was estimated for both species. Frequency analyses were performed in order to follow the best represented cohorts over time and fit three non-asymptotic growth models: Power, Generalised Schnute and the Indeterminate Tanaka model. The CL-TW relationship of juvenile and sub-adultF. brasiliensiswas TW = 3 × 10−5CL3.75and TW = 8 × 10−5CL3.50forF. duorarum, both of which presented positive allometric growth. In both species the Indeterminate Tanaka model proved to be the best fit to the modal groups of the juvenile and sub-adult shrimp due to its ability to describe the seasonal oscillations in shrimp growth.

Small Computer System for Micrograph Analysis

1981 ◽  
Vol 39 ◽  
pp. 270-271
Author(s):  
J. F. Hainfeld ◽  
J. S. Wall
Keyword(s):  
Large Range ◽  
Small Computer ◽  
Black And White ◽  
Contour Maps ◽  
Points Of Interest ◽  
Computer Aided Analysis ◽  
Specialized Hardware ◽  
Additional Memory ◽  
Selection Of ◽  
Publication Quality

Cost reduction and availability of specialized hardware for image processing have made it reasonable to purchase a stand-alone interactive work station for computer aided analysis of micrographs. Some features of such a system are: 1) Ease of selection of points of interest on the micrograph. A cursor can be quickly positioned and coordinates entered with a switch. 2) The image can be nondestructively zoomed to a higher magnification for closer examination and roaming (panning) can be done around the picture. 3) Contrast and brightness of the picture can be varied over a very large range by changing the display look-up tables. 4) Marking items of interest can be done by drawing circles, vectors or alphanumerics on an additional memory plane so that the picture data remains intact. 5) Color pictures can easily be produced. Since the human eye can detect many more colors than gray levels, often a color encoded micrograph reveals many features not readily apparent with a black and white display. Colors can be used to construct contour maps of objects of interest. 6) Publication quality prints can easily be produced by taking pictures with a standard camera of the T.V. monitor screen.

Spherulite Structures in a Melt Spun Fe-Ni Austenitic Steel

1985 ◽  
Vol 43 ◽  
pp. 52-53
Author(s):  
G. M. Michal ◽  
T. K. Glasgow ◽  
T. J. Moore
Keyword(s):  
Austenitic Steel ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Large Range ◽  
Amorphous Structure ◽  
Nucleation And Growth ◽  
Ni Alloys ◽  
Melt Spun ◽  
Crystal Fibers ◽  
Rapidly Solidified

Large additions of B to Fe-Ni alloys can lead to the formation of an amorphous structure, if the alloy is rapidly cooled from the liquid state to room temperature. Isothermal aging of such structures at elevated temperatures causes crystallization to occur. Commonly such crystallization pro ceeds by the nucleation and growth of spherulites which are spherical crystalline bodies of radiating crystal fibers. Spherulite features were found in the present study in a rapidly solidified alloy that was fully crysstalline as-cast. This alloy was part of a program to develop an austenitic steel for elevated temperature applications by strengthening it with TiB2. The alloy contained a relatively large percentage of B, not to induce an amorphous structure, but only as a consequence of trying to obtain a large volume fracture of TiB2 in the completely processed alloy. The observation of spherulitic features in this alloy is described herein. Utilization of the large range of useful magnifications obtainable in a modern TEM, when a suitably thinned foil is available, was a key element in this analysis.

Framework for Selecting Vocabulary for Preliterate Children Who Use Augmentative and Alternative Communication

2019 ◽  
Vol 28 (3) ◽  
pp. 1000-1009
Author(s):  
Allison Bean ◽  
Lindsey Paden Cargill ◽  
Samantha Lyle
Keyword(s):  
Language Impairment ◽  
Augmentative And Alternative Communication ◽  
Developmentally Appropriate ◽  
School Age Children ◽  
Alternative Communication ◽  
School Based ◽  
Selection For ◽  
Nonverbal Children ◽  
Grammatical Structures ◽  
Insufficient Knowledge

Purpose Nearly 50% of school-based speech-language pathologists (SLPs) provide services to school-age children who use augmentative and alternative communication (AAC). However, many SLPs report having insufficient knowledge in the area of AAC implementation. The objective of this tutorial is to provide clinicians with a framework for supporting 1 area of AAC implementation: vocabulary selection for preliterate children who use AAC. Method This tutorial focuses on 4 variables that clinicians should consider when selecting vocabulary: (a) contexts/environments where the vocabulary can be used, (b) time span during which the vocabulary will be relevant, (c) whether the vocabulary can elicit and maintain interactions with other people, and (d) whether the vocabulary will facilitate developmentally appropriate grammatical structures. This tutorial focuses on the role that these variables play in language development in verbal children with typical development, verbal children with language impairment, and nonverbal children who use AAC. Results Use of the 4 variables highlighted above may help practicing SLPs select vocabulary that will best facilitate language acquisition in preliterate children who use AAC.

Teaching Partners to Support Communication for Adults with Acquired Communication Impairment

2013 ◽  
Vol 22 (1) ◽  
pp. 4-15 ◽  
Author(s):  
Laura J. Ball ◽  
Joanne Lasker
Keyword(s):  
Practice Patterns ◽  
Communicative Competence ◽  
Communication Disorders ◽  
Communication Impairment ◽  
Communication Partner ◽  
Communication Partners ◽  
Selection For ◽  
Communication Needs ◽  
End Of Life Communication ◽  
Lateral Sclerosis

Abstract For adults with acquired communication impairment, particularly those who have communication disorders associated with stroke or neurodegenerative disease, communication partners play an important role in establishing and maintaining communicative competence. In this paper, we assemble some evidence on this topic and integrate it with current preferred practice patterns (American Speech-Language-Hearing Association, 2004). Our goals are to help speech-language pathologists (SLPs) identify and describe partner-based communication strategies for adults with acquired impairment, implement evidence-based approaches for teaching strategies to communication partners, and employ a Personnel Framework (Binger et al., 2012) to clarify partners? roles in acquiring and supporting communication tools for individuals with acquired impairments. We offer specific guidance about AAC techniques and message selection for communication partners involved with chronic, degenerative, and end of life communication. We discuss research and provide examples of communication partner supports for person(s) with aphasia and person(s) with amyotrophic lateral sclerosis who have complex communication needs.

Identifying Measurement Invariant Item Sets in Cross-Cultural Settings Using an Automated Item Selection Procedure

Methodology ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 177-188 ◽  
Author(s):  
Martin Schultze ◽  
Michael Eid
Keyword(s):  
Measurement Invariance ◽  
Optimal Solution ◽  
Selection Procedure ◽  
Cross Cultural ◽  
Item Selection ◽  
Ant System ◽  
Item Quality ◽  
Ant System Algorithm ◽  
Selection For ◽  
Selection Of

Abstract. In the construction of scales intended for the use in cross-cultural studies, the selection of items needs to be guided not only by traditional criteria of item quality, but has to take information about the measurement invariance of the scale into account. We present an approach to automated item selection which depicts the process as a combinatorial optimization problem and aims at finding a scale which fulfils predefined target criteria – such as measurement invariance across cultures. The search for an optimal solution is performed using an adaptation of the [Formula: see text] Ant System algorithm. The approach is illustrated using an application to item selection for a personality scale assuming measurement invariance across multiple countries.

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