The Experts below are selected from a list of 13566 Experts worldwide ranked by ideXlab platform
Jørgen Olesen - One of the best experts on this subject based on the ideXlab platform.
-
Lynceus amplopedia sp. nov., A New Laevicaudatan Clam Shrimp with Asymmetrically Modified Thoracopods from Yunnan, China (Crustacea: Branchiopoda).
Zoological studies, 2019Co-Authors: Zandra M S Sigvardt, D. Christopher Rogers, Xiaoyong Chen, Jørgen Olesen, La-orsri SanoamuangAbstract:Laevicaudata has a nearly global distribution, but only a few records from China. We present a new Lynceus (Crustacea: Branchiopoda: Laevicaudata) species, Lynceus amplopedia sp. nov., from Yunnan, China, which shows significant left-right differences in some non-Clasper thoracopods. It can be distinguished from all congeners by asymmetrically modified thoracopods III-VI. In the 'explanate modified' side (usually the left side, occasionally the right) the following modifications are present: endites 4, 5, and endopod enlarged (explanate) (thoracopods III and IV); exopod with 14-15 digitiform processes dorsomedially (thoracopods V and VI); and broad muscular basis (thoracopods III-V). The following modifications are seen in the thoracopods of the opposing 'spinose modified' side (usually the right side, occasionally the left): endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI), and broad muscular basis (thoracopod V). Other unique characters of the new species include: male and female rostrum sinuate, compound eyes protruding, male Claspers with endopod constricted, and endite 3 with two scale patches. We suggest the modified thoracopods may be involved in mating and/or respiration. The diversity of Chinese Lynceus is also discussed.
-
Functional morphology of amplexus (clasping) in spinicaudatan clam shrimps (Crustacea, Branchiopoda) and its evolution in bivalved branchiopods: A video-based analysis.
Journal of Morphology, 2017Co-Authors: Zandra M S Sigvardt, D. Christopher Rogers, Jørgen OlesenAbstract:Male clam shrimps (Crustacea: Branchiopoda: Laevicaudata, Spinicaudata, and Cyclestherida) have their first one or two trunk limb pairs modified as "Claspers," which are used to hold the female during mating and mate guarding. Clasper morphology has traditionally been important for clam shrimp taxonomy and classification, but little is known about how the males actually use the Claspers during amplexus (clasping). Homologies of the various Clasper parts ("movable finger," "large palp," "palm," "gripping area," and "small palp") have long been discussed between the three clam shrimp taxa, and studies have shown that only some structures are homologous while others are convergent ("partial homology"). We studied the Clasper functionality in four spinicaudatan species using video recordings and scanning electron microscopy, and compared our results with other clam shrimp groups. General mating behavior and carapace morphology was also studied. Generally, spinicaudatan and laevicaudatan Claspers function similarly despite some parts being nonhomologous. We mapped Clasper morphology and functionality aspects on a branchiopod phylogeny. We suggest that the Claspers of the three groups were adapted from an original, simpler Clasper, each for a "stronger" grip on the female's carapace margin: 1) Spinicaudata have two Clasper pairs bearing an elongated apical club/gripping area with one setal type; 2); Cyclestherida have one Clasper pair with clusters of molariform setae on the gripping area and at the movable finger apex; and 3) Laevicaudata have one Clasper pair, but have incorporated an additional limb portion into the Clasper palm and bear a diverse set of setae. J. Morphol. 278:523-546, 2017. © 2017 Wiley Periodicals, Inc.
-
Male Claspers in clam shrimps (Crustacea, Branchiopoda) in the light of evolution: a case study on homology versus analogy.
Journal of Experimental Zoology, 2014Co-Authors: Tomonari Kaji, Martin Schwentner, Martin Fritsch, Jørgen Olesen, Stefan RichterAbstract:Male “clam shrimps” possess highly modified first (and second) trunk limbs for clasping the carapace of females during copulation. Claspers are present in all three clam shrimp taxa (Laevicaudata, Spinicaudata, and Cyclestherida) but despite striking similarities in their morphology and function, the matter of their homology is controversial. In this study, we address the question of the homology and evolution of these structures by comparing the developmental transformation of an unspecialized trunk limb into a Clasper. In addition, we study the musculature and the nervous system in trunk limbs and Claspers using confocal laser scanning microscopy. We establish that most (but not all) of the various parts of the Claspers are homologous between clam shrimp taxa. We suggest that a single pair of Claspers was already present in the ground pattern of Diplostraca, probably most comparable to those in Cyclestherida. The Claspers, therefore, do not represent a case of analogy. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 269–280, 2014. © 2014 Wiley Periodicals, Inc.
-
Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda) and functional morphology of male Claspers in a phylogenetic context: a video-based analysis.
PLOS ONE, 2014Co-Authors: Zandra M S Sigvardt, Jørgen OlesenAbstract:Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis) and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males). Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs) of anterior trunk limbs modified as Claspers. Previous studies have shown that Clasper morphology is important in a phylogenetic context, and that some parts of the Claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata). It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male Claspers was studied in detail by close-up video recordings. The movable “finger” of the Clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable “finger”, possibly indirectly providing sensory input on the “finger” position. A brief comparative study of the Claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan Claspers. The presence of two pairs of Claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding.
-
External morphology of the male of Cyclestheria hislopi (Baird, 1859) (Crustacea, Branchiopoda, Spinicaudata), with a comparison of male Claspers among the Conchostraca and Cladocera and its bearing on phylogeny of the ‘bivalved’ Branchiopoda
Zoologica Scripta, 1996Co-Authors: Jørgen Olesen, Joel W Martin, Ewald W. RoesslerAbstract:The adult male of Cyclestheria hislopi, sole member of the spinicaudate conchostracan clam shrimp family Cyclestheriidae and a species of potential phylogenetic importance, is described for the first time. Several previously unknown features are revealed. Among these are (1) the morphology of the dorsal organ, which is roughly similar in shape to the supposedly homologous structure in other clam shrimps but bears a relatively large, centrally located pore unique to the species; (2) an anterior cuticular pore presumably leading to the ‘internal’ space surrounding the compound eyes, and thereby homologous to the same pore in other clam shrimps and in the Notostraca; (3) the spination and setation of the antennae and thoracopods, and (4) the mature male first thoracopods (Claspers). The male Claspers are paired and essentially equal in size and shape on right and left sides of the body. The second pair of thoracopods are not modified as Claspers, a situation different from all other spinicaudate families but shared (plesiomorphic we propose) with the laevicaudatans and most cladocerans. The Claspers bear a field of special spine-like setae on the extremity of the ‘palm’; this setal type, previously unrecognized, is unique to Cyclestheria. The palm of the Clasper also bears two palps (one very small), as in other conchostracan species (both laevicaudatans and spinicaudatans). The movable finger of the Clasper, modified from the thoracopod endopod, bears a row of long setae along its outer extremity, also unique. Cyclestheria exhibits a mixture of characters, some unique and others typical of the Spinicaudata (Conchostraca). Cladoceran Clasper types are briefly reviewed. as are the Claspers in the Spinicaudata and Laevicaudata (Conchostraca). Morphology of the Clasper of Cyclestheria shows typical spinicaudate characters. It is suggested that Claspers on the first thoracopods may be a synapomorphy for the Conchostraca and the Cladocera. The possible role of Cyclestheria or a Cyclestheria-like ancestor in cladoceran phylogeny is briefly discussed in light of recent suggestions (Martin and Cash-Clark, 1995) of cladoceran monophyly and possible ancestral relationships with this genus. Some possibilities concerning the phylogenetic position of Cyclestheria–either as a sister group to the rest of the Spinicaudata or as a sister group to the Cladocera—are discussed.
Albert D. Farrell - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of the Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) as a measure of treatment effectiveness with psychiatric inpatients.
Assessment, 2006Co-Authors: Joanna E. Strong Kinnaman, Albert D. Farrell, Sarah W. BisconerAbstract:Assessment procedures to evaluate inpatient treatment effectiveness can provide information to inform clinical practice. The Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) represents a standardized approach to assess patients' target problems that combines elements of individualized and nomothetic approaches. Although previous evaluations of CASPER with other patient populations have been encouraging, its use as a measure of change with an inpatient population has not been examined. In this study, 75 psychiatric inpatients completed CASPER and the Behavior and Symptom Identification Scale-32 (BASIS-32) at hospital admission and discharge. Results supported the concurrent validity of CASPER as a measure of pre- and posttreatment functioning and suggested that CASPER may provide a sensitive measure of change during inpatient treatment. Findings also supported the notion that patients' ratings of the extent to which their treatment focused on the problems they identified as a high priority were related to their overall treatment satisfaction.
-
Evaluation of the Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) interview with a psychiatric inpatient population.
Journal of Clinical Psychology, 2003Co-Authors: Joanna E. Strong, Albert D. FarrellAbstract:The Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER; Farrell & McCullough-Vaillant, 1996) includes a computer-based interview designed to assess functioning across a broad range of areas. The psychometric properties of scales derived from this interview were examined in a sample of 191 patients from the admissions wards of a state psychiatric hospital. Few participants had difficulty completing the computerized interview, and most rated their reactions to it positively. Item analyses and confirmatory factor analysis largely replicated the structure reported in a previous study of outpatients. Support was found for scales representing Physical Complaints, Worry, Hopelessness, Assertiveness, Hostility/Anger, Thought Problems, Psychotic Symptoms, Substance Use, and Suicidal Thoughts and Behavior. Comparison of scales from the CASPER and the Behavior and Symptom Identification Scale-32 (BASIS-32; Eisen & Culhane, 1999) supported the convergent and discriminant validity of several scales. Support also was found for the CASPER Global Functioning scale. Overall, results supported the use of the CASPER as a valuable tool for assessing inpatient functioning.
-
Evaluation of the Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) as a measure of treatment effectiveness in an outpatient training clinic
Psychological Assessment, 1999Co-Authors: Albert D. FarrellAbstract:This study evaluated the validity of the Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER), a system that identifies target problems and monitors treatment outcomes Pre-and posttreatment data were obtained from 78 clients and their therapists in an outpatient training clinic. CASPER scales were significant correlated with the Brief Symptom Inventory (BSI) and with therapist ratings on the Global Assessment Scale (GAS) at both intake and posttreatment. These measures also showed significant pre- to posttreatment changes. The largest effect sizes were found on CASPER individualized outcome measures. Residual change scores and posttreatment improvement ratings derived from CASPER were significantly correlated with BSI and GAS change scores. There was moderate agreement between clients' and therapists' ratings; clients tended to rate their functioning higher than did therapists on several CASPER scales.
Zandra M S Sigvardt - One of the best experts on this subject based on the ideXlab platform.
-
Lynceus amplopedia sp. nov., A New Laevicaudatan Clam Shrimp with Asymmetrically Modified Thoracopods from Yunnan, China (Crustacea: Branchiopoda).
Zoological studies, 2019Co-Authors: Zandra M S Sigvardt, D. Christopher Rogers, Xiaoyong Chen, Jørgen Olesen, La-orsri SanoamuangAbstract:Laevicaudata has a nearly global distribution, but only a few records from China. We present a new Lynceus (Crustacea: Branchiopoda: Laevicaudata) species, Lynceus amplopedia sp. nov., from Yunnan, China, which shows significant left-right differences in some non-Clasper thoracopods. It can be distinguished from all congeners by asymmetrically modified thoracopods III-VI. In the 'explanate modified' side (usually the left side, occasionally the right) the following modifications are present: endites 4, 5, and endopod enlarged (explanate) (thoracopods III and IV); exopod with 14-15 digitiform processes dorsomedially (thoracopods V and VI); and broad muscular basis (thoracopods III-V). The following modifications are seen in the thoracopods of the opposing 'spinose modified' side (usually the right side, occasionally the left): endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI), and broad muscular basis (thoracopod V). Other unique characters of the new species include: male and female rostrum sinuate, compound eyes protruding, male Claspers with endopod constricted, and endite 3 with two scale patches. We suggest the modified thoracopods may be involved in mating and/or respiration. The diversity of Chinese Lynceus is also discussed.
-
Functional morphology of amplexus (clasping) in spinicaudatan clam shrimps (Crustacea, Branchiopoda) and its evolution in bivalved branchiopods: A video-based analysis.
Journal of Morphology, 2017Co-Authors: Zandra M S Sigvardt, D. Christopher Rogers, Jørgen OlesenAbstract:Male clam shrimps (Crustacea: Branchiopoda: Laevicaudata, Spinicaudata, and Cyclestherida) have their first one or two trunk limb pairs modified as "Claspers," which are used to hold the female during mating and mate guarding. Clasper morphology has traditionally been important for clam shrimp taxonomy and classification, but little is known about how the males actually use the Claspers during amplexus (clasping). Homologies of the various Clasper parts ("movable finger," "large palp," "palm," "gripping area," and "small palp") have long been discussed between the three clam shrimp taxa, and studies have shown that only some structures are homologous while others are convergent ("partial homology"). We studied the Clasper functionality in four spinicaudatan species using video recordings and scanning electron microscopy, and compared our results with other clam shrimp groups. General mating behavior and carapace morphology was also studied. Generally, spinicaudatan and laevicaudatan Claspers function similarly despite some parts being nonhomologous. We mapped Clasper morphology and functionality aspects on a branchiopod phylogeny. We suggest that the Claspers of the three groups were adapted from an original, simpler Clasper, each for a "stronger" grip on the female's carapace margin: 1) Spinicaudata have two Clasper pairs bearing an elongated apical club/gripping area with one setal type; 2); Cyclestherida have one Clasper pair with clusters of molariform setae on the gripping area and at the movable finger apex; and 3) Laevicaudata have one Clasper pair, but have incorporated an additional limb portion into the Clasper palm and bear a diverse set of setae. J. Morphol. 278:523-546, 2017. © 2017 Wiley Periodicals, Inc.
-
Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda) and functional morphology of male Claspers in a phylogenetic context: a video-based analysis.
PLOS ONE, 2014Co-Authors: Zandra M S Sigvardt, Jørgen OlesenAbstract:Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis) and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males). Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs) of anterior trunk limbs modified as Claspers. Previous studies have shown that Clasper morphology is important in a phylogenetic context, and that some parts of the Claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata). It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male Claspers was studied in detail by close-up video recordings. The movable “finger” of the Clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable “finger”, possibly indirectly providing sensory input on the “finger” position. A brief comparative study of the Claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan Claspers. The presence of two pairs of Claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding.
Sarah W. Bisconer - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of the Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) as a measure of treatment effectiveness with psychiatric inpatients.
Assessment, 2006Co-Authors: Joanna E. Strong Kinnaman, Albert D. Farrell, Sarah W. BisconerAbstract:Assessment procedures to evaluate inpatient treatment effectiveness can provide information to inform clinical practice. The Computerized Assessment System for Psychotherapy Evaluation and Research (CASPER) represents a standardized approach to assess patients' target problems that combines elements of individualized and nomothetic approaches. Although previous evaluations of CASPER with other patient populations have been encouraging, its use as a measure of change with an inpatient population has not been examined. In this study, 75 psychiatric inpatients completed CASPER and the Behavior and Symptom Identification Scale-32 (BASIS-32) at hospital admission and discharge. Results supported the concurrent validity of CASPER as a measure of pre- and posttreatment functioning and suggested that CASPER may provide a sensitive measure of change during inpatient treatment. Findings also supported the notion that patients' ratings of the extent to which their treatment focused on the problems they identified as a high priority were related to their overall treatment satisfaction.
Cory T Overton - One of the best experts on this subject based on the ideXlab platform.
-
Tidal and seasonal effects on survival rates of the endangered California clapper rail: does invasive Spartina facilitate greater survival in a dynamic environment?
Biological Invasions, 2014Co-Authors: Cory T Overton, Michael L Casazza, John Y Takekawa, Donald R. Strong, Marcel HolyoakAbstract:Invasive species frequently degrade habitats, disturb ecosystem processes, and can increase the likelihood of extinction of imperiled populations. However, novel or enhanced functions provided by invading species may reduce the impact of processes that limit populations. It is important to recognize how invasive species benefit endangered species to determine overall effects on sensitive ecosystems. For example, since the 1990s, hybrid Spartina ( Spartina foliosa × alterniflora ) has expanded throughout South San Francisco Bay, USA, supplanting native vegetation and invading mudflats. The endangered California clapper rail ( Rallus longirostris obsoletus ) uses the tall, dense hybrid Spartina for cover and nesting, but the effects of hybrid Spartina on clapper rail survival was unknown. We estimated survival rates of 108 radio-marked California clapper rails in South San Francisco Bay from January 2007 to March 2010, a period of extensive hybrid Spartina eradication, with Kaplan–Meier product limit estimators. Clapper rail survival patterns were consistent with hybrid Spartina providing increased refuge cover from predators during tidal extremes which flood native vegetation, particularly during the winter when the vegetation senesces. Model averaged annual survival rates within hybrid Spartina dominated marshes before eradication (Ŝ = 0.466) were greater than the same marshes posttreatment (Ŝ = 0.275) and a marsh dominated by native vegetation (Ŝ = 0.272). However, models with and without marsh treatment as explanatory factor for survival rates had nearly equivalent support in the observed data, lending ambiguity as to whether hybrid Spartina facilitated greater survival rates than native marshland. Conservation actions to aid in recovery of this endangered species should recognize the importance of available of high tide refugia, particularly in light of invasive species eradication programs and projections of future sea-level rise.
-
does mercury contamination reduce body condition of endangered california clapper rails
Environmental Pollution, 2012Co-Authors: Joshua T Ackerman, Robin A Keister, Collin A Eaglessmith, Michael L Casazza, Cory T Overton, John Y Takekawa, Mark P. HerzogAbstract:We examined mercury exposure in 133 endangered California clapper rails (Rallus longirostris obsoletus) within tidal marsh habitats of San Francisco Bay, California from 2006 to 2010. Mean total mercury concentrations were 0.56 mg/g ww in blood (range: 0.15e1.43), 9.87 mg/g fw in head feathers (3.37e22.0), 9.04 mg/g fw in breast feathers (3.68e20.2), and 0.57 mg/g fww in abandoned eggs (0.15e2.70). We recaptured 21 clapper rails and most had low within-individual variation in mercury. Differences in mercury concentrations were largely attributed to tidal marsh site, with some evidence for year and quadratic date effects. Mercury concentrations in feathers were correlated with blood, and slopes differed between sexes (R 2 ¼ 0.58e0.76). Body condition was negatively related to mercury concentrations. Model averaged estimates indicated a potential decrease in body mass of 20e22 g (5e7%) over the observed range of mercury concentrations. Our results indicate the potential for detrimental effects of mercury contamination on endangered California clapper rails in tidal marsh habitats. Published by Elsevier Ltd.