bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of the gonadal germinal epithelium during sex reversal and seasonal testicular cycling in the protogynous swamp eel, synbranchus marmoratus Bloch 1795 (teleostei, synbranchidae)
Authors: Lo Nostro F. , Grier H. , Andreone L. , Guerrero G.A. 
Published: May 2003

AbstractThe swamp eel, Synbranchus marmoratus, is a protogynous, diandric species. During sex reversal, the ovarian germinal epithelium, which forms follicles containing an oocyte and encompassing follicle cells during the female portion of the life cycle, produces numerous invaginations, or acini, into the ovarian stroma. Within the acini, the gonia that formerly produced oocytes become spermatogonia, enter meiosis, and produce sperm. The acini are bounded by the basement membrane of the germinal epithelium. Epithelial cells of the female germinal epithelium, which formerly became follicle (granulosa) cells, now become Sertoli cells in the developing testis. Subsequently, lobules and testicular ducts form. The swamp eel testis has a lobular germinal compartment in both primary and secondary males, although the germinal compartment in testes of secondary males resides within the former ovarian lamellae. The germinal compartment, supported by a basement membrane, is composed of Sertoli and germ cells that give rise to sperm. Histological and immunohistochemical techniques were used to describe the five reproductive classes that were observed to occur during the annual reproductive cycle: regressed, early maturation, mid‐maturation, late maturation, and regression. These classes are differentiated by the presence of continuous or discontinuous germinal epithelia and by the types of germ cells present. Synbranchus marmoratus has a permanent germinal epithelium. Differences between the germinal compartment of the testes of primary and secondary males were not observed. J. Morphol. 257:107–126, 2003. © 2003 Wiley‐Liss, Inc.
Morphology and histochemistry of the peripheral olfactory organ in the round goby, Neogobius melanostomus (Teleostei: Gobiidae)
Authors: Belanger Rachelle M. , Smith Cortney M. , Corkum Lynda D. , Zielinski Barbara S. 
Published: May 2003

AbstractThis first comprehensive study of the peripheral olfactory organ from a representative of the large and economically important order of teleost fishes, the Perciformes, shows a compact structure with olfactory sensory neurons distributed widely throughout the olfactory chamber. The spatial organization of the nasal cavity in the bottom‐dwelling round goby (Gobiidae, Neogobius melanostomus) was examined using impression material injection, immunocytochemistry, and transmission electron microscopy. The olfactory chamber contains a single olfactory lamella; prominent dorsocaudal lachrymal and ethmoidal accessory nasal sacs are situated ventrocaudal to the chamber. The location of the olfactory mucosa within the olfactory chamber is novel for teleost fish, as it extends beyond the ventral surface to the lateral and dorsal regions. Microvillar olfactory sensory neurons and ciliated olfactory sensory neurons were identified by transmission electron microscopy and the spatial distribution of these two cell types was assessed through immunocytochemistry against olfactory receptor coupled G‐proteins. Both Gαolf‐immunoreactive ciliated olfactory sensory neurons and the Gαo‐immunoreactive microvillar form were located throughout the olfactory epithelium. Ciliated crypt cells were Gαo immunoreactive and were found throughout the olfactory epithelium of some specimens. The widespread occurrence of olfactory sensory neurons in the olfactory chamber supports the idea that olfactory signaling is important to the survival of the round goby. The prominence of the lachrymal and ethmoidal accessory nasal sacs indicates the capacity to regulate the flow of odorant molecules over the sensory surface of the olfactory sensory neurons, possibly through a pump‐like mechanism driven by opercular activity associated with gill ventilation. J. Morphol. 257:62–71, 2003, © 2003 Wiley‐Liss, Inc.
Spatial expression patterns of skin‐type antifreeze protein in winter flounder (Pseudopleuronectes americanus) epidermis following metamorphosis
Authors: Murray Harry M. , Hew Choy L. , Fletcher Garth L. 
Published: May 2003

AbstractTwo isotypes of Type I antifreeze protein (AFP), the liver‐type and the skin‐type, have been described from adult winter flounder (Pseudopleuronectes americanus). Although the liver‐type AFP has been well studied, the skin‐type has just begun to be characterized. It appears to have a wide tissue distribution, be expressed constitutively, and the absence of a signal sequence suggests it is active intracellularly. The current study was designed to examine the onset of skin‐type AFP expression during the thickening of the epidermis at metamorphosis from both the nucleic acid and protein levels. The epidermis appeared as a thin layer overlying a thickened dermis at metamorphosis and showed a gradual increase in thickness through the first fall and winter. The onset of skin‐type antifreeze expression occurred in conjunction with this epidermal thickening. In situ hybridization and immunohistochemistry showed a distribution of mRNA and skin‐type AFP specific for the epidermis and epidermal pavement cells. The AFP immunoproduct showed a distribution intimate with the pavement cell membrane and through the interstitial spaces. This distribution suggests that the AFP may be important in slowing ice crystal formation in these interstitial regions and thus reducing cellular damage due to osmotic imbalance. J. Morphol. 257:78–86, 2003. © 2003 Wiley‐Liss, Inc.
Structure of spermatodoses in shield‐back bushcrickets (Tettigoniidae, Tettigoniinae)
Authors: Vahed Karim 
Published: May 2003

AbstractMany aspects of the reproductive anatomy and physiology of tettigoniids have been studied extensively. These include the large, externally visible spermatophores and the bundles of sperm, known as spermatodesms. However, spermatodoses, spermatophore‐like structures found within the spermatheca, seem to have been almost completely overlooked: their structure has not been described since 1913 and they have subsequently received only passing mention in the literature. Each time the female mates, a separate spermatodose is formed. Here I use photographs, from light‐microscopy, of whole and sectioned spermatodoses to describe the external and internal structure of spermatodoses of nine different genera within the subfamily Tettigoniinae. The structure of the spermatodoses is very similar for the different genera. Each spermatodose is pear‐ or onion‐shaped and consists of a thin outer layer, enclosing a thick, gelatinous inner layer. A large sperm mass occupies the bulbous end of the spermatodose, while a thin sperm‐tube leads from the sperm mass, along the center of the elongated neck of the spermatodose, and appears to exit at the pointed‐tip of the spermatodose. Feather‐like bundles of sperm (spermatodesms) were clearly visible within the sperm mass and also appeared to be present within the sperm‐tube. The wall of the sperm tube appeared to be composed of material similar to that of the outer layer of the spermatodose. Within the spermatheca, spermatodoses appeared to be stratified in that only one of them ever occupied the position nearest to the spermathecal duct. The possible function of spermatodoses is discussed: it is proposed that they have evolved as a result of sexual conflict and function to protect the sperm from being destroyed by the female while they are in storage. J. Morphol. 257:45–52, 2003. © 2003 Wiley‐Liss, Inc.
Functional morphology of extreme jaw protrusion in Neotropical cichlids
Authors: Waltzek Thomas B. , Wainwright Peter C. 
Published: May 2003

AbstractThe New World cichlids Petenia splendida and Caquetaia spp. possess extraordinarily protrusible jaws. We investigated the feeding behavior of extreme (here defined as greater than 30% head length) and modest jaw‐protruding Neotropical cichlids by comparing feeding kinematics, cranial morphology, and feeding performance. Digital high‐speed video (500 fps) of P. splendida, C. spectabile, and Astronotus ocellatus feeding on live guppy prey was analyzed to generate kinematic and performance variables. All three cichlid taxa utilized cranial elevation, lower jaw depression, and rotation of the suspensorium to protrude the jaws during feeding experiments. Extreme anterior jaw protrusion in P. splendida and C. spectabile resulted from augmented lower jaw depression and anterior rotation of the suspensorium. Morphological comparisons among eight cichlid species revealed novel anterior and posterior points of flexion within the suspensorium of P. splendida and Caquetaia spp. The combination of anterior and posterior loosening within the suspensorium in P. splendida and Caquetaia spp. permitted considerable anterior rotation of the suspensorium and contributed to protrusion of the jaws. Petenia splendida and C. spectabile exhibited greater ram distance and higher ram velocities than did A. ocellatus, resulting primarily from increased jaw protrusion. Petenia splendida and C. spectabile exhibited lower suction feeding performance than A. ocellatus, as indicated by lower suction‐induced prey movements and velocities. Thus, extreme jaw protrusion in these cichlids may represent an adaptation for capturing elusive prey by enhancing the ram velocity of the predator but does not enhance suction feeding performance. J. Morphol. 257:96–106, 2003. © 2003 Wiley‐Liss, Inc.
Pericardium of the frog, Rana esculenta, is morphologically designed as a lymphatic space
Authors: Cerra Maria Carmela , Amelio Daniela , Tavolaro Palmira , Palma Antonio , Marcianò Vito , Farina Felicia 
Published: May 2003

AbstractThe importance of the pericardium and the pericardial fluid (PF) in the control of cardiac function has emerged over the past few years. Despite the acknowledgment that amphibians are exposed to both dehydration and excessive water accumulation, nothing is known about their pericardial structure and the morphological basis of the PF formation. We have studied the parietal pericardium (PP) morphology in Rana esculenta by electron microscopy. SEM images of the inner surface, which lines the pericardial cavity, revealed the presence of large vesicles and many small circular openings. TEM observations showed that the PP is made up of an inner mesothelial lining, often constituted by two layers of very flat cells lying on a basal membrane and of regularly oriented collagen bundles. The PP outer surface is lined by a layer of flat cells, without a basal membrane. The mesothelial cells had overlapping boundaries with complex intercellular connections and a rich pool of caveolae opened in the direction of both the pericardial cavity and intercellular spaces. These cells indicate an intense intracellular and/or intercellular transfer of fluids and substances. The intraperitoneal injection of the idromineral hormone, Val5‐ANG II, induced PP modifications, particularly evident at the level of the structures involved in the transmesothelial traffic. These lymphatic‐like traits suggest that the frog PP represents a large lymphatic sac, subject to paracrine‐endocrine remodeling, which can actively adjust the PF, influencing the composition and volume of the myocardial interstitial fluid. J. Morphol. 257:72–77, 2003. © 2003 Wiley‐Liss, Inc.
A desert octodontid rodent, Tympanoctomys barrerae, uses modified hairs for stripping epidermal tissue from leaves of halophytic plants
Authors: Berman Susan L. 
Published: May 2003

AbstractDesert rodents that consume halophytic plants must have adaptations for coping with the high salt content of the leaves. A kidney capable of excreting very concentrated urine is one method. Another is removal of the hypersaline epidermis by means of chisel‐like incisors prior to ingestion of the leaves. Tympanoctomys barrerae has evolved a unique refinement of the latter adaptation. It possesses two bundles of stiffened hairs on either side of the palate just caudal to the incisors. The bundles vibrate against the lower incisors, removing the epidermis from the leaves. The efficiency of the operation is significantly greater than with the use of incisors alone. Such a device has not been described in any other mammal. The facial muscles associated with the lips, the cheek vibrissae, and the oral cavity are described in T. barrerae and the nonhalophilic octodontid Octomys mimax. M. buccinatorius pars intermaxillaris is the only muscle in direct contact with the bristle bundles. Other anatomical features found in T. barrerae that may be associated with this feeding device are: 1) a much enlarged and mobile lower labial pad operated by Mm. buccinatorius pars orbicularis oris, pars longitudinalis profunda, and mandibularis cranialis profunda; 2) two oral glands not described in other rodents; and 3) a shortened tongue. Although, taken as a whole, this epidermal stripping device is unique to T. barrerae, most of its features have evolved by modification of structures present in the facial region of more generalized rodents. J. Morphol. 257:53–61, 2003. © 2003 Wiley‐Liss, Inc.
Australian drought: the interference of multi‐spectral global standing modes and travelling waves
Authors: White Warren B. , McKeon Greg , Syktus Jozef 
Published: May 2003

AbstractExtreme drought has devastated the flora, fauna, and regional economy in rangeland grazing districts over Australia for 3–5 years duration every 20 to 30 years throughout the 20th century. We investigate the source of drought occurring in five example grazing districts in eastern and central Australia. We find year‐to‐year variability in grazing district rainfall (GDR) during the summer rainy season (November to March) composed of quasi‐biennial, interannual, quasi‐decadal, and interdecadal signals from 1900 to 1999. However, the longer period signals dominate, accounting for the interdecadal quasi‐periodicity of the drought/flood cycle. We find these GDR signals associated with corresponding global standing modes and travelling waves in covarying sea‐surface temperature (SST) and sea‐level pressure (SLP) anomalies. These global SST/SLP modes/waves influence the GDR signals by altering the troposphere moisture flux converging onto the grazing districts from regional tropical and extra‐tropical oceanic source regions. We construct statistical models to determine whether the evolution of these global SST/SLP modes/waves over the oceanic source regions can hindcast corresponding GDR signals from one year to the next. When these models allow for modulation of the modes/waves, they hindcast ∼1/3 of the variance in the GDR indices at 1 year lead, including the drought episodes. We find drought resulting from the constructive interference of the dry phases of the quasi‐decadal and interdecadal global SST/SLP modes/waves, accompanied by a weakening of year‐to‐year variability associated with either weak quasi‐biennial and interannual modes/waves or their destructive interference. Copyright © 2003 Royal Meteorological Society
Simulation of impact of projected climate change on wheat in India
Authors: Attri S. D. , Rathore L. S. 
Published: May 2003

AbstractThe problem of global climate change due to natural processes and anthropogenic sources and its impacts on world food security in general and its regional impacts in particular have come to forefront of the scientific community in recent years. Though the uncertainty of projected climate change at the regional level is higher, it is still necessary to assess its impacts on crop productivity for formulating response strategies. Climate change scenarios projected by the middle of the current century, based on the latest studies, were created and the impacts of concurrent changes of temperature and CO2 on the growth, development and yields of wheat in northwest India were quantified using a state‐of‐the‐art dynamic simulation model. Yield enhancements of the order of 29–37% and 16–28% under rainfed and irrigated conditions respectively in different genotypes were observed under a modified climate (Tmax + 1.0°C, Tmin + 1.5°C, 2 × CO2). Any further increase beyond 3 °C cancelled the beneficial impact of enhanced CO2.Adaptation measures to mitigate the potential impact of climate change included possible changes in sowing dates and genotype selection. Enhancement of sowing by 10 days in late‐sown cultivars and delaying of sowing by 10 days in normally sown cultivars resulted in higher yields under a modified climate, whereas a reduction in yield was observed in the reverse strategies. Copyright © 2003 Royal Meteorological Society
Responses of China's summer monsoon climate to snow anomaly over the Tibetan Plateau
Authors: Qian Y. F. , Zheng Y. Q. , Zhang Y. , Miao M. Q. 
Published: May 2003

AbstractThe climatological features of the winter snow depth over the Tibetan Plateau and the summer precipitation in China are diagnosed using datasets obtained from 78 snow observation stations and 160 rainfall stations during 1957 to 1998. The climatic effects of the snow anomaly over the Tibetan Plateau on the regional summer monsoon climate in China are diagnosed and numerically simulated by use of a regional climate model (RegCM2). The singular value decomposition technique is adopted to diagnose the relationships between the previous winter and spring plateau snow depth anomalies and the spring and summer regional precipitation in China. It is found that the snow depth anomaly, especially in winter, is one of the factors influencing precipitation in China; however, it is perhaps not the only one, and even not the most important one. Nevertheless, it is proved that the winter snow anomaly over the Tibetan Plateau is relatively more important than that in spring for the regional precipitation in China. Results of numerical simulations show that the snow anomaly over the plateau has effects that are evident on China's summer monsoon climate. The increase of both snow cover and snow depth can delay the onset and weaken the intensity of the summer monsoon obviously, resulting in a decrease in precipitation in southern China and an increase in the Yangtze and Huaihe River basins. The influence of the winter snow depth is more substantial than that of both the winter snow cover and the spring snow depth. The mechanism of how the plateau snow anomaly influences the regional monsoon climate is briefly analysed. It is found that snow anomalies over the Tibetan Plateau change the soil moisture and the surface temperature through the snowmelt process at first, and subsequently alter heat, moisture and radiation fluxes from the surface to the atmosphere. Abnormal circulation conditions induced by changes of surface fluxes may affect the underlying surface properties in turn. Such a long‐term interaction between the wetland and the atmosphere is the key process resulting in later climatic changes. Copyright © 2003 Royal Meteorological Society
Spring northward retreat of Eurasian snow cover relevant to seasonal and interannual variations of atmospheric circulation
Authors: Ueda Hiroaki , Shinoda Masato , Kamahori Hirotaka 
Published: May 2003

AbstractAn observational study is made of the seasonal and interannual variations of spring snow‐disappearance over the Eurasian continent and the circulation mechanisms causing those variations. The spring northward retreat of the snow boundary over the East European Plain (EEP) between 30 and 60° E is faster (0.4° per day) than to the east of the Ural Mountain range (0.3° per day). These migrations of the snow boundary lag behind the appearance of the surface air temperature 0 °C by about 1 to 5 pentads.The analyses of the atmospheric heat and moisture budgets showed that the seasonal intrusion of warm air associated with southwesterly winds is primarily responsible for the rapid snowmelt in March and April over the EEP. In addition, the adiabatic heating of descending air plays a secondary role in the snowmelt in mid‐March. On an interannual time scale, horizontal warm advection also plays an essential role in the spring northward retreat of snow cover extent.The present study confirms the previous finding that the surface air temperature anomalies, produced during the seasonal snow‐disappearance period, diminished in May, suggesting a weak dynamical linkage between the EEP snow cover and Asian summer monsoon. Copyright © 2003 Royal Meteorological Society
Sea‐surface temperature co‐variability in the Southern Atlantic and Indian Oceans and its connections with the atmospheric circulation in the Southern Hemisphere
Authors: Fauchereau N. , Trzaska S. , Richard Y. , Roucou P. , Camberlin P. 
Published: May 2003

AbstractThe relationship between sea‐surface temperature (SST) inter‐annual variability at the subtropical and midlatitudes of the southern Atlantic and Indian Oceans and its links with the atmospheric circulation in the Southern Hemisphere are investigated over the 1950–1999 period. Exploratory analysis using singular value decomposition and further investigations based on simple indices show that a large part of regional SST variability is common between the southwestern parts of both basins at subtropical and midlatitudes during the austral summer. Interestingly, these areas are also significantly associated with the far southwestern Pacific (Tasman Sea area). The patterns and time series of co‐variability between the southern Atlantic and Indian Oceans are shown to correspond to SST modes previously described in the literature as ‘subtropical dipoles’, independently for the Atlantic and Indian Oceans. Composite analyses show that austral summers characterized by simultaneous warm (and to a lesser extent cold) SST anomalies in the southwestern (northern) part of both southern oceans are related to atmospheric anomalies mainly involving a southward shift and a strengthening of the subtropical high‐pressure systems over both basins. These anomalies are embedded in a hemispheric signal associating two cores of positive pressure anomalies within the South Pacific anticyclone. The global picture appears to have a wave number 4 spatial structure. The associated low‐level wind and latent heat‐flux anomalies and the lags between atmospheric variables and SST anomalies are consistent with an atmospheric forcing on the ocean. Potential links of these patterns with large‐scale modes of climate variability in the Southern Hemisphere are discussed. Copyright © 2003 Royal Meteorological Society.
Homogeneity of 20th century European daily temperature and precipitation series
Authors: Wijngaard J. B. , Klein Tank A. M. G. , Können G. P. 
Published: May 2003

AbstractDaily European station series (1901–99) of surface air temperature and precipitation from the European Climate Assessment dataset are statistically tested with respect to homogeneity. A two‐step approach is followed. First, four homogeneity tests are applied to evaluate the daily series. The testing variables used are (1) the annual mean of the diurnal temperature range, (2) the annual mean of the absolute day‐to‐day differences of the diurnal temperature range and (3) the wet day count (threshold 1 mm). Second, the results of the different tests are condensed into three classes: ‘useful’, ‘doubtful’ and ‘suspect’. A qualitative interpretation of this classification is given, as well as recommendations for the use of these labelled series in trend analysis and variability analysis of weather extremes. In the period 1901–99, 94% of the temperature series and 25% of the precipitation series are labelled ‘doubtful’ or ‘suspect’. In the sub‐period 1946–99, 61% of the temperature series and 13% of the precipitation series are assigned to these classes. The seemingly favourable scores for precipitation can be attributed to the high standard deviation of the testing variable, and hence the inherent restricted possibilities for detecting inhomogeneities. About 65% of the statistically detected inhomogeneities in the temperature series labelled ‘doubtful’ or ‘suspect’ in the period 1946–99 can be attributed to observational changes that are documented in the metadata. For precipitation this percentage is 90%. Copyright © 2003 Royal Meteorological Society