bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occupancy-abundance models for predicting densities of three leaf beetles damaging the multipurpose tree Sesbania sesban in eastern and southern Africa
Authors: Sileshi G. , Hailu G. , Mafongoya P.L. 
Published: January 2006

AbstractMesoplatys ochroptera Stål, Exosoma and Ootheca spp. seriously damage sesbania, Sesbania sesban (L.) Merril, a multipurpose leguminous tree widely used in tropical agroforestry. This is discouraging farmers from expanding the planting of sesbania in various agroforestry systems in eastern and south-central Africa. Rapid methods are needed for estimation of population densities of these beetles for decisionmaking in pest management. A study was conducted with the objectives of determining the existence of any positive relationship between the occupancy and abundance of Mesoplatys, Exosoma and Ootheca and determining the model that best predicts abundance from occupancy for rapid estimation of population densities. The Poisson model assuming spatial randomness, the negative binomial distribution (NBD) model assuming spatial aggregation, the Nachman model without any distribution assumption, and a General model incorporating spatial variance-abundance and occupancy-abundance relationships were fitted to data on adult M. ochroptera, Exosoma and Ootheca from western Kenya, southern Malawi and eastern Zambia. Very strong variance to abundance relationships were observed in the spatial pattern of all three beetles. The occupancy-abundance relationships were also positive and strong in all beetles. The occupancy and abundance predicted by the four models were closest to the observed at lower densities compared with higher beetle densities. At higher population densities, the NBD and the General model gave better fit for M. ochroptera and Exosoma. For Ootheca populations, the Poisson and NBD models gave better fit at higher population densities. The relationships established here can be used as guide to estimate beetle densities for decision-making in pest management.
Verb schema use and input dependence in 5‐year‐old children with Specific Language Impairment (SLI)
Authors: Riches N. G. , Faragher B. , Conti‐Ramsden G. 
Published: January 2006

AbstractBackground: It has been argued that children with Specific Language Impairment (SLI) use language in a conservative manner. For example, they are reluctant to produce word‐plus‐frame combinations that they have not heard in the input. In addition, there is evidence to suggest that their utterances replicate lexical and syntactic material from the immediate language environment.Aims: This study investigated further the linguistic conservatism of children with SLI. It addressed the hypothesis that these children have difficulties using syntactic schemas in a verb‐general manner. It employed a technique pioneered by Childers and Tomasello in 2001 that aims to develop verb‐general representations through the presentation of appropriate exemplars. In addition, it tested the hypothesis that children with SLI present with input‐dependent language use.Methods & Procedures: Twenty‐four children with SLI (mean age 5;6 years) were matched to 23 typically developing children (mean age 3;5 years) on overall language abilities. The children experienced play sessions designed to simulate exemplar‐based learning. Facilitative exemplars consisted of sentences that alternated between nouns and pronouns in the argument slots, e.g. ‘Pooh's churning the plate. See, he's churning it’. The children were divided evenly into two groups. One group experienced facilitative exemplars, while the other group heard exemplars with no variation in the argument positions. The training effect was assessed with a procedure in which the children heard novel verbs in a non‐transitive frame and were required to produce them in a transitive frame. In addition, the argument types of the children's responses (nouns versus pronouns) were analysed to investigate the issue of input dependence.Outcomes & Results: Few of the children produced novel verbs in the transitive. This result may indicate difficulties using the transitive, although a number of methodological difficulties may be responsible for this finding. As hypothesized, the children with SLI demonstrated greater input dependence in terms of the kind of arguments they used in responses during the training sessions.Conclusions: Potential reasons for the low response rate of both groups during the testing stage are explored and a number of methodological adjustments proposed. It is argued that the greater input dependence of the children with SLI may reflect a tendency to reduce processing load within a limited capacity system. It is proposed that input dependence could be a fruitful new area for SLI research and an important issue in the design and delivery of therapy programmes.
A simple proof for folds on both sides in complexes of graph homomorphisms
Authors: Kozlov Dmitry 
Published: January 2006

In this paper we study implications of folds in both parameters of Lovász’

H
o
m

(
−
,
−
)

\mathtt {Hom}(-,-)

complexes. There is an important connection between the topological properties of these complexes and lower bounds for chromatic numbers. We give a very short and conceptual proof of the fact that if

G
−
v

G-v

is a fold of

G
G

, then

bd
⁡

H
o
m

(
G
,
H
)

\operatorname {bd}\mathtt {Hom}(G,H)

collapses onto

bd
⁡

H
o
m

(
G
−
v
,
H
)

\operatorname {bd}\mathtt {Hom}(G-v,H)

, whereas

H
o
m

(
H
,
G
)

\mathtt {Hom}(H,G)

collapses onto

H
o
m

(
H
,
G
−
v
)

\mathtt {Hom}(H,G-v)

. We also give an easy inductive proof of the only nonelementary fact which we use for our arguments: if

φ
\varphi

is a closure operator on

P
P

, then

Δ
(
P
)

\Delta (P)

collapses onto

Δ
(
φ
(
P
)
)

\Delta (\varphi (P))

.
Spectral rigidity of group actions: Applications to the case gr⟨𝑡,𝑠;𝑡𝑠=𝑠𝑡²⟩
Authors: Ageev Oleg 
Published: January 2006

We apply a technique to study the notion of spectral rigidity of group actions to a group

gr

⟨
t
,
s
;

t
s
=
s

t
2

⟩

\mbox {gr}\langle t,s ; \ ts=st^2\rangle

. As an application, we prove that there exist rank one weakly mixing transformations conjugate to its square, thereby giving a positive answer to a well-known question.
Acquired hook‐avoidance in the pike Esox lucius L. fished with artificial and natural baits
Authors: Beukemaj J. J. 
Published: January 2006

Tagged pike Esox lucius L. in a drainable pond were fished by hook and line, using either a spinner or a small live fish as bait. Catch per unit effort could be used as a measure for catchability because all captured pike were immediately returned to the pond and mortality was low.Catchability to spinner fishing decreased to very low levels after about half of the population had been caught in this way. Catchability to live bait fishing remained unaffected both by intensive spinner and live bait fishing.It was difficult to capture pike more than once by spinning. In live bait fishing, on the other hand, the number of recaptures closely matched the number expected if catchability remains unaffected by earlier capture.The advantages are discussed of the use of artificial baits over live baits in hook and line fishing for pike.
Studies on ulcerative dermal necrosis of salmonids
Authors: Roberts Ronald J. , Shearer W. M. , Munro A. L. S. , Elson K. G. R. 
Published: January 2006

The gross pathology and histopathology of a series of 150 cases of UDN disease of salmon Safmo sulur L. from a number of Scottish rivers is described. The lesions appeared first as small grey areas on the heads of affected fish, which gradually enlarged in size, ulcerated and became infected with fungus of the Saprolegniu group. Histologically, the earliest lesion was an acantholysis of the suprabasal cells of the epidermis developing into transient bullae which rapidly sloughed to produce a raggcd irregular epiderm's. Once the base‐ment membrane was breached secondary infection by fungi rapidly ensued.The histopathology, in the early stages, was consistent with possible viral infection, or anoxic atrophy but it was considered that the most similar lesion from mammalian experi‐ence, was that of the Pemphigus group of dermatoses.
Some observations on the food of the gwyniad Coregonus clupeoides pennantii Valenciennes of Llyn Tegid (Lake Bala), North Wales
Authors: Haram O. J. , Jones J. W. 
Published: January 2006

The seasonal variations in the diet of adult gwyniad Coregonus clupeoides pennantii=C. lavaretus from Llyn Tegid, North Wales were studied. Stomachs were examined to determine fullness, volume and identity of contents.A clear seasonal cycle in food intake was found. Feeding rates were low from January to April but increased during the summer (May‐June) and remained at a high level until December. The period of low feeding intensity coincided with the time of spawning and the time of annulus formation of both scales and otoliths. The diet showed seasonal changes and two main periods were distinguished : December to July, when the fish fed mainly on bottom fauna, and August to November, when the diet included both bottom fauna and midwater and surface foods.The gwyniad were shown to be opportunistic in feeding, the composition of the diet reflecting availability of food items rather than selective feeding on the part of the fish.
The anatomy and histology of the alimentary tract of the carnivorous fish the pike Esox lucius L.
Authors: Bucke David 
Published: January 2006

The alimentary tract of the pike is described, relating its feeding habits to its intestinal gut histology. It is a carnivorous species having a short oesophagus, pouch‐like stomach and a short intestine with two convolutions. Stratified epithelium with columnar cells and many goblet cells are present in the oesophagus, columnar epithelial cells only in the stomach, and both cell types in the intestine.Eosinophils in the mucosa of the oesophagus originate from connective tissue cells and lymphocytes and neutrophils are present. The lamina propria is composed of a stratum granulosum, stratum compactum, blood vessels and loose areolar tissue. The stratum compactum is a strengthening substance, composed of collagen, characteristic of carnivorous teleosts. The circular and longitudinal muscle layers and serosa are similar to those of other carnivorous teleosts.The pancreas and liver are briefly described, the pancreas being the unusual compact type not often found in teleosts. The B cells are seen in the periphery and a cells in the centre of the islets. The liver is a unilobular organ, having oil storage as a major function.The distribution of goblet cell mucin is given, differentiating it into neutral and acid mucosubstances. Nine levels of alimentary tract were examined in the mucin distribution study. The functions of mucin in the pike are digestion, absorption, protection and lubrication.
The rainbow trout Salmo gairdneri (Rich.) fishery of Lake Titicaca
Authors: Everett G. V. 
Published: January 2006

Rainbow trout were introduced to Lake Titicaca in 1942. A commercial trout canning operation started in 1961 but terminated in 1970. Data for this study were collected in 1966 and 1967, with the object of examining the life history, biology, and commercial fishery of Titicaca rainbow trout. Trout were caught commercially and experimentally by gillnets in different parts of the lake.Lake Titicaca lies across the border of Peru and Bolivia at 3212 m above sea level. The physico‐chemical characteristics of the lake appear ideal for self‐sustaining populations of rainbow trout. Growth was constant throughout the year, and was good in relation to growth rates of rainbow trout in other parts of the world. Spawning took place in the tributaries in the winter. Recruitment to the fishery occurs in 7.62 cm stretch mesh gillnets at about 27 cm fork length.The total annual commercial catch increased to 500 metric tons in 1965 before subsequently decreasing. The simplest explanation for the decline in total catch would be the increase in fishing mortality due to increased fishing effort, although it is possible that the decline in water level has had some effect. It appeared possible that the lake could sustain an annual catch of about 350 tons.
Bimodal distribution of length of juvenile Atlantic salmon (Salmo salar L.) under artificial rearing conditions
Authors: Thorpe J. E. 
Published: January 2006

In 52 populations of juvenile Atlantic Salmon, Salmo salar L., from 14 pairings of wild parents, reared at the Almondbank smolt rearing station between 1973 and 1976 in circular radial‐flow tanks, bimodality in the frequency distribution of length and weight has been characteristic by the first autumn of growth, and has become progressively clearer during the following winter.The examination of 13 populations showed the modes did not correspond to separate sexes, from four others it was shown they did not correspond to immature fish and precociously mature males. It is suggested that the two modes correspond to subpopulations smoltifying at ages (t) and (t+1) years. The age‐composition of the smolt‐run originating from individual year‐classes of salmon in four Scottish rivers was found to be consistent with stocks having size‐group segregations, at the time of the first smolt emigration, similar to those found among Almondbank experimental material. It is inferred that bimodality of size distribution is the norm among sibling populations of juvenile Atlantic salmon.
Comparison between serum values of pond and intensive raceway cultured channel catfish Ictalurus punctatus (Rafinesque)
Authors: Warner Mark C. , Williams R. Whitney 
Published: January 2006

Blood serum components in channel catfish (Ictalurus punctatus) were compared between raceway (with low dissolved oxygen) and pond populations. Normal limits were defined for the pond populations, for each of 18 variables, as ± two standard deviations. Carbon dioxide, blood urea nitrogen, total protein, uric acid, creatinine, sodium, and total bilirubin were all lower in fish raised in raceways. Carbon dioxide and sodium had the greatest reductions; all reductions were statistically significant.Alkaline phosphatase, inorganic phosphorus, calcium, cholesterol, and glucose values were higher in raceway fish, but only alkaline phosphatase and glucose were significantly higher.
The leucocytes of fish: A review
Authors: Ellis A. E. 
Published: January 2006

The data available in the literature concerning fish thrombocytes, lymphocytes, monocytes, macrophages and granulocytes is discussed and the dearth of reliable information concerning the functional identity of most fish leucocytes is underlined. The methods of applying nomenclatures to fish leucocytes encountered in the literature is discussed in some detail and found to be unsatisfactory. An attempt is made to simplify the confused and conflicting reports by applying the concepts which have recently arisen in the field of mammalian immunology. Nomenclatures are assigned to cells on a functional and morphological basis where sufficient data exists.Thrombocytes are responsible for clot formation and are considered to be distinct, separate and unrelated to lymphocytes. Lymphocytes are recognised as immuno‐competent cells though as yet little information exists on their role in immune mechanisms. Recent work is furnishing interesting results in this direction, especially in the origin of lymphocyte populations and their co‐operative responses in immunity. Previous references to monocytes and macrophages in fish are confused and the literature is discussed in the light of the new classification of the Mononuclear Phagocyte System.Very few experimental data exist concerning granulocytic leucocytes in fish, indeed the presence of such cells with granulocytic functions still requires proof. Cells with morphological similarity to mammalian granulocytes do exist in fish but information essential for an understanding of their role in defence mechanisms is lacking. The state of the literature concerning the eosinophil, basophil and mast cell in fish is so confused that an entirely new approach to a study of these cells is warranted. It is hoped that this review will supply guidelines for future research.
Ultrastructure of the chorion and its micropyle apparatus in the mature Fundulus heteroclitus (Walbaum) ovum
Authors: Kuchnow Karl P. , Scott James R. 
Published: January 2006

The ovum ‘membranes’ and the micropyle apparatus of mature, extruded ova of Fundulus heteroclitus were examined by scanning electron microscopy. The ovum is covered by a thin jelly coat comprised of a dense mat of 0.3‐0.5 urn fibrils, except for a 50–100 um fibril‐free zone surrounding the micropyle apparatus. The micropyle apparatus consists of a 50–100 um diameter funnel‐shaped vestibule, at the bottom of which is a circular aperture 4–5 μ in diameter leading to the micropyle canal which traverses the entire chorion layer. The inner micropyle aperture, 2–3 um diameter, apposes the inner ovoplasm mass.The chorion is the major protective coating of the ovum. It consists of a thin (0.4 μm) outer zone, a thicker (9–12 μ), lamellated inner zone with 4–10 lamellae, and sometimes an innermost crystalline zone, varying in thickness from 1–13 μm. The extreme variability in the structure of the lamellated and crystalline zones of the chorion suggests that generalizations concerning ovum membranes can be misleading.
The use of opercular bones in the study of age and growth in Labeo senegalensis from Lake Kainji, Nigeria
Authors: Blake C. , Blake B. F. 
Published: January 2006

Check marks were found on the scales and opercular bones of Labeo senegalensis from Lake Kainji, Nigeria. The scale marks were often indistinct and difficult to interpret, but an attempt was made to determine age from the opercular bones.At least two check marks per year were found on the opercular bones, one of these occurring during June‐July, and the other during January. The relationship between opercular length and fish total length was plotted logarithmically and back‐calculations of length made.Problems of interpretation are discussed in relation to possible causes of ring formation.
Sustained swimming speeds and myotomal muscle function in the trout, Salmo gairdneri
Authors: Walker M. Greer , Emerson L. 
Published: January 2006

Rainbow trout were trained for 3–4 weeks in a flume at swimming speeds of 1, 2 and 3 l s−1. For each experiment growth rates were estimated and by measuring the hypertrophy of red and mosaic skeletal muscle fibres their function was described at particular swimming speeds and compared with earlier experiments on coalfish using the same technique.Maximum growth, compared with controls in still water, occurred at swimming speeds of 1 l s−1. At this speed the trout mosaic muscle fibres hypertrophied by 40% but the red muscle fibres showed only a 25% hypertrophy. It is suggested that natural swimming speeds are close to 1Ls−l and the trout mosaic fibres are better adapted for use at this speed in comparison with coalfish white muscle fibres.
Effects of salinity and starvation on the alimentary canal anatomy of the rainbow trout Salmo gairdneri Richardson
Authors: MacLeod M. G. 
Published: January 2006

A study has been made of the effects of salinity, starvation and salinity‐starvation interactions on the structure of the alimentary canal of immature rainbow trout Salmo gairdneri Richardson. Intestinal and rectal cross‐sectional areas and the height of the intestinal villi increased with salinity. The thickness of none of the tissue layers measured in the intestine and rectum, including the columnar epithelium and the tunica propria, was influenced by salinity. There was a significant negative correlation between salinity and mucous cell distribution density in both the intestine and rectum. In trout acclimatised to salinities of 15.0 p.p.t. (parts per thousand) and above, there was a high incidence of deep depressions in the columnar epithelium. The oesophagus and stomach were not visibly affected by salinity.There was a marked decrease in intestinal and rectal cross‐sectional area and height of intestinal villi with starvation except in 32.5 p.p.t. sea water. Mean intestine epithelial cell height decreased with starvation at 32.5 p.p.t. A 48 day period of starvation had little effect on the posterior oesophagus and the cardiac stomach.
The effects of impoundment and regulation upon the stomach contents of fish at Cow Green, Upper Teesdale
Authors: Crisp D. T. , Mann R. H. K. , McCormack Jean C. 
Published: January 2006

The stomach contents of 1003 brown trout, 1551 bullheads and 800 minnows taken from the reservoir basin and below the dam, before and after impoundment of the river Tees, were examined. Their composition reflected observations by other workers on river and reservoir benthos, except for the increase in numbers of Hydra and Nais below the dam, and Mollusca, Hirudinea and oligochaetes in the reservoir.Trout below the dam ate more Ephemeroptera nymphs and Chironomidae larvae but fewer terrestrial casualties after river regulation, whereas bullheads ate more Mollusca but fewer Plecoptera nymphs. In both species Baetidae nymphs increased in numerical importance relative to Ecdyonuridae. Trout, but not bullheads, took zooplankton discharged from the reservoir.Before impoundment, trout within the reservoir basin ate chiefly benthic organisms and terrestrial casualties. Inundated terrestrial material, mainly earthworms, formed the bulk of their food for at least three years after impoundment, whilst from the second year onwards Chironomidae and, in some years, Gammarus became increasingly important. Zooplankton was taken by all sizes of reservoir trout.Bullheads within the reservoir basin ate chiefly river benthos before impoundment, with Ephemeroptera and Plecoptera nymphs predominant in older fish, and aquatic Diptera and Coleoptera also important in the fry. After impoundment, Chironomidae and Gammarus were the main items taken by older bullheads, and Chironomidae and micro‐crustacea by the fry. Among all sizes of minnow, Chironomidae, micro‐crustacea and detritus increased in numerical importance after impoundment.
Some haematological responses of normal and splenectomized rainbow trout Salmo gairdneri to a 12% blood loss
Authors: Lane H. C. 
Published: January 2006

Anaemia can be induced in Rainbow trout by removing 12 % of the blood volume by cardiac puncture. Recovery from such an anaemia has been monitored in both normal and splenectomized fish. After the bleeding there is a decrease in red cell numbers, haematocrit and blood haemoglobin concentration. Although recovery in normal trout was not complete within 27 days, which was the period of the observations, it was seen as a replenishing of red cell numbers, haematocrit and blood haemoglobin concentration. Mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC), both depressed by the bleeding, did not appear to recover during the experimental period.Splenectomy reduced erythropoietic intensity. After bleeding all the parameters studied were more depressed than those found in normal trout, and recovery was not noted. Blood haemoglobin and red cell numbers did not have the same post‐bleeding pattern as normal individuals; MCH and MCHC values remained markedly depressed.Splenic involvement was further demonstrated by bleeding trout for a second time from both normal and splenectomized groups. In contrast to the response of normal animals, there was a further deterioration of red cell numbers and blood haemoglobin concentration in splenectomized individuals.