The bias associated with the dispersion of length at age in the estimation of growth and mortality parameters from uni-modal length-frequency data

Values of M and M/K extracted from simulated uni-modal length-frequency data representing 28 fish stocks were biased. The bias exceeded 20% when the life span of the stock was <5 or >15 years.     

Influence of body weight/age on the food intake,growth and conversion efficiency of Gambusia affinis

On a restricted food supply of Tubifex tubifex (2h/day) the fish consumed only 69.5 mg dry food/g live fish/day and grew only to 25.6 mg live body weight by the 30th day of it's age, while those fed ad libitum consumed 94.7 mg/g/day and attained a body weight of 125.9 mg live weight by the 30th day. Conversion efficiency (K₁) averaged to 8.3% in the former and 14.1% in the latter series, throughout the 30 day experimental period.Feeding rate of the test series fed individually and at ad libitum, decreased from 780 mg dry food/g dry fish/day for a fish weighing 4 mg dry weight to 180 mg/g/ day for one weighing 41 mg, exhibiting a log-log relationship to the body weight (Y = 2.20140–0.5639 X). Growth rate also decreased as a log-log function with increasing body weight (Y = 1.2309–0.4384 X).     

Age determination of corvina reina (Cynoscion albus) in the Gulf of Nicoya, Costa Rica, based on examination and analysis of hyaline zones, morphology and microstructure of otoliths

This is the first age determination study for Cynoscion albus , a large tropical sciaenid, using otolith morphology and daily increment analysis. The practicality of both methods for age determination is illustrated by their consistent estimates of age and von Bertalanffy growth parameters. The daily increment analysis was used to validate the surface readings. An alternative, otolith morphometrics, is shown to hold promise for rapid prediction of fish age. Two multivariate linear regression models using gross otolith dimensions can estimate the age of C. albus to within 1 year. Growth parameter estimates are: from surface readings: L =127.5cm with K =0.12; from daily increment readings: L = 122.1 cm with K =0.17. Implications for the stock assessment of tropical fish using size instead of age are discussed.     

Reconstruction of adaptive radiation in insular habitats using integrated biogeographic information

Aim To develop an analytical method for accurately reconstructing the biogeographic events associated with adaptive radiation in a system of insular habitats. Location An idealized, two-dimensional model system of insular habitats is based on the altitudinally stratified vegetation zones on the island-like mountains of eastern Africa. Methods The model system is treated as a two-dimensional array of insular habitats, and adaptive radiation is treated as a ‘space-filling’ process according to six premises based on uniformitarian principles. Previous approaches to this class of problems have used (1) Hennig's progression rule, (2) optimization of biogeographic character states, and (3) reasoned argumentation with an intuitive synthesis of information. The strengths and limitations of these previous approaches are evaluated. Results A closed analytical method is presented that accurately reconstructs biogeographic events. This methodological approach integrates atomized information back up to the appropriate level of biological organization and has general applicability to phylogenetic analysis. Main conclusions In a truly evolutionary approach to phylogenetic systematics and biogeography, the initial analysis of the pattern of descent should be complemented with a subsequent analysis of the pattern of modification. The method presented here offers one approach to analysing the pattern of modification, which in this case constitutes biogeographic movement.     

Recent data about age at menarche in the biscay province (Basque Country, Spain)

Data on menarcheal age were collected by thestatus quo method on a sample of 808 schoolgirls (8–19 years of age), from the Margen Izquierda area of the Biscay province (Basque Country). Probit analysis provided a mean age at menarche of 12.5±0.05 years with a standard deviation of 1.0 years. The result was compared with data from other previous Basque studies and related to age at PHV of the same sample.     

Stopped-flow solution scattering using synchrotron radiation: Apparatus,data collection and data analysis

We have constructed an experimental system, under remote control, for stopped-flow X-ray scattering using synchrotron radiation. It has been used, in conjunction with an annular detector and its associated electronics, to obtain good scattering curves, with time-slices as short as 200 ms, in a new study of the dissociation of the enzyme complex aspartate transcarbamylase. The data have been analysed by new statistical methods, and they agree well with the results from parallel chemical quench experiments. For studying dissociation reactions, stopped-flow X-ray scattering is a quite practical method, which need not use very much more material than conventional stopped-flow experiments.     

Modelling avian biodiversity using raw,unclassified satellite imagery

Applications of remote sensing for biodiversity conservation typically rely on image classifications that do not capture variability within coarse land cover classes. Here, we compare two measures derived from unclassified remotely sensed data, a measure of habitat heterogeneity and a measure of habitat composition, for explaining bird species richness and the spatial distribution of 10 species in a semi-arid landscape of New Mexico. We surveyed bird abundance from 1996 to 1998 at 42 plots located in the McGregor Range of Fort Bliss Army Reserve. Normalized Difference Vegetation Index values of two May 1997 Landsat scenes were the basis for among-pixel habitat heterogeneity (image texture), and we used the raw imagery to decompose each pixel into different habitat components (spectral mixture analysis). We used model averaging to relate measures of avian biodiversity to measures of image texture and spectral mixture analysis fractions. Measures of habitat heterogeneity, particularly angular second moment and standard deviation, provide higher explanatory power for bird species richness and the abundance of most species than measures of habitat composition. Using image texture, alone or in combination with other classified imagery-based approaches, for monitoring statuses and trends in biological diversity can greatly improve conservation efforts and habitat management.     

Pointwise testing with functional data using the Westfall-Young randomization method

We consider hypothesis testing with smooth functional data byperforming pointwise tests and applying a multiple comparisonsprocedure. Methods based on general inequalities, such as Bonferroni’smethod, do not perform well because of the high correlationbetween observations at nearby points. We consider the multiplecomparison procedure proposed by Westfall & Young (1993)and show that it approximates a multiple comparison correctionfor a continuum of comparisons as the grid for pointwise comparisonsbecomes finer. Simulations and an application verify that thisresult applies in practical settings.     

Age and growth rate determinations of an intertidal bivalve, Phacosoma japonicum, using internal shell increments

A venerid bivalve Phacosoma japonicum (Reeve) occurring commonly in the Japanese coastal area preserves periodic growth lines in the shell cross-section. Long-term shell growth patterns of this species have been traced for many individuals on the intertidal flat of the Seto Inland Sea, west Japan. Sclerochronological analysis of these individuals and specimens collected monthly shows that several growth cessation marks within their shells are formed during the winter of each year prior to spawning. Hence the marks were used for age and growth rate determinations. As large individuals showed little shell growth for more than two years after the formation of 7 or 8 annual increments, this species probably has a lifespan of more than ten years. Shell growth patterns of this species based on annual increments can be accurately approximated by a von Bertalanffy curve. The number of microgrowth increments formed during a year tends to decrease with age, although it varies markedly among specimens of the same age. Furthermore, even in summer during rapid shell growth, the microgrowth increments do not represent daily and/or sub-daily tidal rhythms in many specimens. The results of this study and those by several authors strongly suggest that the annual increments are the key for age and growth rate determinations of both living and fossil bivalve species.     

Sulphur, thiols, and disulphides in the fish epidermis, with remarks on keratinization

Energy dispersive x-ray (EDX) analysis and qualitative and quantitative histochemistry were applied to study the distribution and contents of sulphur, thiols and disulphides in the epidermis of the river lamprey Lampetra fluviatilis , the lesser spotted dogfish Scyliorhinus canicula and the brown trout Salmo trutta fario . Thiols generally reacted weakly throughout the entire epidermis, whereas disulphide reactions were more distinct and differentiated. In the river lamprey, the concentrations of -S-S- groups clearly increased in the developing mucous cells from the stratum basale to the stratum superficiale; skein cells and granular cells reacted negatively to weakly. In the lesser spotted dogfish, amounts of disulphides appeared at moderate concentrations, and only goblet cells displayed a strong reaction. In the brown trout, filament cells showed low concentrations or weak reactions of disulphides, goblet cells and the most outer superficial cells stained strongly. Sulphur distribution and contents generally supported the histochemical observations in normal epidermis cells (absolute sulphur contents: 41–59 mM), only the brown trout showed high amounts of sulphur in the stratum basale (81 mM). The findings corroborate the view that there is an inverse correlation between keratinization and mucous secretion in normal fish epidermis. The sometimes distinct contents of disulphides in the outer mucous layer indicate that this system could endure higher mechanical stress than predictable from its large amounts of neutral glycoproteins.     

Enhancing dopamine detection using a glassy carbon electrode modified with MWCNTs, quercetin, and Nafion

Glassy carbon (GC) electrode was modified using multi-wall carbon nanotubes (MWCNTs), quercetin (Q) and Nafion^® in this sequence. The thus modified electrode was used for the detection of dopamine (DA) in the presence of equimolar ascorbic acid (AA). It is demonstrated in this study that MWCNTs can increase the current response of DA by five-fold and Q can reduce the oxidation overpotential of DA by about 60 mV, compared to these parameters obtained with a bare GC electrode. It is also shown that a layer of Nafion^® can virtually eliminate the interference of AA for the detection of DA. The GC/MWCNTs/Q/Nafion^® electrode (hereafter also called composite electrode) shows a current density of about 900 μA cm⁻² for DA, compared to the value of 80 μA cm⁻² of the GC electrode and to the value of 390 μA cm⁻² of the GC/MWCNTs electrode. The 11-fold enhancement in the sensitivity of the GC electrode for DA determination is attributed to the composite modification of the electrode, and is substantiated through various cyclic voltammetric experiments. Cyclic voltammetry (CV) and linear sweep voltammetry were used to characterize the electrodes. Calibration curves of batch and flow systems were obtained by amperometry for the detection of DA. Additionally, the composite modified electrode was tested with a human serum sample for the determination of DA and was found to be promising at our preliminary experiments.     

The first find in southern Georgia of fossil honey from the Bronze Age,based on palynological data

The results of a palynological analysis of the organic content of earthenware pots from the Kodiani burial mound (27th–25th centuries b.c.) are reported. The character of the palynological spectrum differs significantly from that of a buried soil within the same burial mound. In the samples taken from the pots, pollen concentration is very high, pollen grains are perfectly preserved and an abundance of pollen from insect-pollinated plants is recorded. It is well known that these features are peculiar to honey palynospectra. In all three pots the pollen of Rosaceae, a family of plants that produce good honey, is dominant. However, the second, third and fourth most dominant pollen types in all three samples are different. For example, Tilia pollen is the second dominant in only one pot. In the second pot, Apiaceae and Poaceae are predominant, and in the third pot, Poaceae, both wild and cultural, is the second dominant. It is clear that the different pots contained different types of honey. The variety of honey types indicates highly developed bee-keeping in the Early Bronze Age. In the same regions of Georgia, agriculture was also highly developed. Wheat cultivation was very important. According to the palynospectra, the landscape and climate of this period were probably quite different to those of today.     

First data on rabbit dung as a water fertilizer in tropical fish culture and its effect on the growth of Oreochromis niloticus (Teleostei, Cichlidae)

The influence of rabbit dung on water quality, plankton occurrence and Nile tilapia growth (Oreochromis niloticus) was studied. pH and total alkalinity increased, dissolved oxygen concentration decreased but not below the critical level whilst the nitrogen parameters were not affected in a significant way. An important increase of plankton was recorded and was reflected in a decrease of transparency: the phytoplankton density was 2.7 times that of the controls. Tilapia growth rate in the manure treatments was 5.1 times that of the control group; no significant difference in survival rates was observed.     

Sex determination using discriminant function analysis in Indigenous (Kurubas) children and adolescents of Coorg,Karnataka, India: A lateral cephalometric study

Aim: To test the validity of sex discrimination using lateral cephalometric radiograph and discriminant function analysis in Indigenous (Kuruba) children and adolescents of Coorg, Karnataka, India. Methods and materials: Six hundred and sixteen lateral cephalograms of 380 male and 236 females of age ranging from 6.5 to 18 years of Indigenous population of Coorg, Karnataka, India called Kurubas having a normal occlusion were included in the study. Lateral cephalograms were obtained in a standard position with teeth in centric occlusion and lips relaxed. Each radiograph was traced and cephalometric landmarks were measured using digital calliper. Calculations of 24 cephalometric measurements were performed. Results: Males exhibited significantly greater mean angular and linear cephalometric measurements as compared to females (p < 0.05) (Table 5). Also, significant differences (p < 0.05) were observed in all the variables according to age (Table 6). Out of 24 variables, only ULTc predicts the gender. The reliability of the derived discriminant function was assessed among study subjects; 100% of males and females were recognized correctly. Conclusion: The final outcome of this study validates the existence of sexual dimorphism in the skeleton as early as 6.5 years of age. There is a need for further research to determine other landmarks that can help in sex determination and norms for Indigenous (Kuruba) population and also other Indigenous population of Coorg, Karnataka, India.     

Applications of a novel biodetection system to saliva using protein fingerprints with data processing

A fundamental method has been developed focusing on a facile and rapid examination of periodontal disease. Periodontal disease is an oral disease thought to affect 80% of adults, and early detection with treatment is desirable for the improvement of the quality of life. Unfortunately conventional methods are not consistent as the disease is caused by a number of undefined bacteria and detection relies on the skills of the dentist. Thus an objective detection system is required. We have performed an experiment on saliva using a novel biodetection system, designated PepTenChip®. A disease model for saliva was prepared using a specimen from a healthy subject and a mixture of hemoglobin (f-Hb) and lactate dehydrogenase (LDH), which is used as a periodontal disease marker protein with healthy saliva. PepTenChip® is a peptide microarray in which fluorescent labelled structured peptides are immobilized on a novel amorphous carbon substrate. Since the peptides used as capture molecules are fluorescently labelled, labeling of analytes is not necessary. The fluorescence intensity change before and after application of analytes are detected rather than the ON/OFF detection common to conventional microarrays using a set of antigen–antibody. The fluorescence intensity value changes according to the concentration of captured protein allowing the generation of protein fingerprint (PFP) and dendrograms. The present method does not rely on a “one to one” interaction, unlike conventional biodetection, and advantages can be envisaged in the case of an undefined or unknown cause of disease. The statistical analyses, such as multivariate analyses, allow classification of the type of proteins added in saliva as mimetics of disease. PepTenChip® system is useful and convenient for examination of periodontal disease in health care.     

A stromal cell line from rainbow trout spleen, RTS34st, that supports the growth of rainbow trout macrophages and produces conditioned medium with mitogenic effects of leukocytes

Summary A rainbow trout spleen cell line, RTS34, was developed from a long-term hemopoietic culture. This cell line consisted of a mixed stromal cell layer with an associated cell population of macrophage-like cells that formed proliferative foci and released nonadherent progeny cells into the culture medium. A stromal cell line, RTS34st, was isolated from the RTS34 cell line. RTS34st cultures contained cells with fibroblast-like and epithelial-like morphologies and showed enhanced [³H]thymidine incorporation in response to either FBS or rainbow trout serum. The combination of FBS and trout serum was synergistic. Conditioned medium from RTS34st stimulated thymidine incorporation by peripheral blood and head kidney leukocytes, but not by leukocytes from the spleen. In addition, RTS34st provided a hemopoietic inductive microenvironment for immature precursor cells, selectively supporting the growth of macrophage-like cells. Therefore, RTS34st appears useful for studying the different roles of the stroma in regulating hemopoiesis in fish.     

Life history and production of Paranephrops zealandicus in a forest stream, with comments about the sustainable harvest of a freshwater crayfish

1. Life history and production were assessed for the crayfish Paranephrops zealandicus in three reaches of a headwater stream with a catchment of regenerating coniferous-broadleaf forest in the south-east of the South Island of New Zealand.
2. Crayfish density ranged from 3 to 4 m⁻² in riffles and 4–12 m⁻² in pools, depending on reach. Crayfish biomass (4–33 g AFDW m⁻²) and annual production (2–11 g AFDW m⁻²) were high compared with values reported elsewhere, while P:B ratio was low (0.33–0.43). This substantial production was dependent primarily upon high biomass rather than high growth rate.
3. The crayfish of this population rank amongst the longest lived and slowest growing ever recorded. Individuals estimated to be 16+ year of age were not uncommon. Females became reproductively active at 6+ year. Fewer than 4% of females carried eggs, and young remained attached to females for at least 15 months.
4. We propose that characteristics of this population are the consequence of a cool thermal regime (mean daily stream temperature = 7.0 °C, range 1.8–11.9 °C), and that low biomass turnover and poor reproductive rate precludes any sustainable commercial harvest of crayfish from streams in New Zealand with similar thermal regimes.     

Developing tests of successional hypotheses with size-structured populations,and an assessment using long-term data from a Ugandan rain forest

In 1947, W. J. Eggeling published an account of forest succession at Budongo, Uganda. This interpretation was based on a large-scale comparative plot study, performed in the 1930s and 1940s. This account, with its implication that species richness declines in late succession, endures as a controversial corner-stone in theories and disputes about community diversity. Data have now been collected over six decades from five of Eggeling's original plots.This paper evaluates Eggeling's successional interpretation of the Budongo vegetation. The first set of analyses assesses the consistency of the original data with the predictions of compositional progression and convergence implicit in Eggeling's model. The second analyses do the same for the time-series observations. A logical approach shows how temporal information may be derived from both between plot, and within plot, evaluations using size-structured data. A Detrended-Correspondence-Analysis (DCA) of canopy-tree composition, from the original data, ranks the plots in perfect correspondence to Eggeling's successional sequence. A development-scoring procedure is developed using passive-ordination against this sequence; this is then applied to composition by plot and stem-size class.Eggeling's original data are consistent with each prediction assessed. The analyses show compositional progression and apparent convergence across the plot series, and also progression and convergence within each plot. A monodominant-Cynometra forest is the natural end-point of this progression. The time-series results, though in apparent agreement for one early successional plot, do not generally accord with Eggeling's ideas. The analyses illustrate a general means for evaluating explicit and implicit compositional trends in communities with structured populations.     

Discovery and enumeration of Swahilian Coastal Forests in Lindi region,Tanzania, using Landsat TM data analysis

The Swahilian Coastal Forests in eastern Africa are recognised to be a globally important habitat containing large numbers of endemic species, yet are still poorly known over much of their extent. Floristic diversity and endemism in these forests appears to peak in SE Tanzania, where only a few forests have hitherto been surveyed. We carried out a digital analysis of Landsat Thematic Mapper (TM) data to identify other potential areas of Coastal Forest in Lindi and Kilwa Districts, SE Tanzania, followed by a field survey to ground truth and fine-tune our analysis. Our analysis has identified, mapped and sub-classified all remaining areas of Coastal Forest in Lindi and Kilwa Districts, and includes the discovery of a large and hitherto undescribed area of Coastal Forest at Namatimbili, which would make it one of the largest known blocks of contiguous Coastal Forest in eastern Africa. This forest furthermore appears to be minimally impacted by human disturbance. Given the rapidly increasing threats to forested vegetation in this area, urgent efforts are required by the conservation community to ensure the immediate and continued protection of Namatimbili forest.