The effect of body size on food consumption, absorption efficiency, respiration, and ammonia excretion by the inland silverside, Menidia beryllina (Cope) (Osteichthyes: Atherinidae)

The inland silverside, Menidia beryllina (Cope), is an annual zooplanktivore that occurs in estuarine and freshwater habitats along the Atlantic and Gulf of Mexico coasts and drainages of the United States. Experiments were conducted at 25 ± 1°C to quantify the relationship between mean dry weight (W_D) and rates of energy gain from food consumption (C), and energy losses as a result of respiration (R) and ammonia excretion (E) during routine activity and feeding by groups of fish. The absorption efficiency of ingested food energy (A) was also quantified. Rates of C, E, and R increased with W_D by factors (b in the equation y = aW_D^b) equal to 0.462, 0.667, and 0.784, respectively. Mean (±SE) rates of energy loss during feeding were 1.6 ± 0.1 (R) and 3.4 ± 0.6 (E) times greater than those for unfed fish. Absorption efficiency was independent of W_D and estimated to be 89% of C. From these measurements, the surplus energy available for growth and activity (G) and growth efficiency (K₁) were estimated. Over the range in sizes of juveniles and adults (5–500 mg W_D), predicted G and K₁ values decreased from 7.42 to 0.20 J mg fish^?1 day^?1 and 63 to 21%, respectively. Measured and predicted bioenergetic parameters are discussed within an ecological context for a northern population of this species.     

Estimation of leaf area at the level of branch,tree and stand inCryptomeria japonica

The frequency distribution of diameter (x) in foliage shoot segments, ø(x), was examined in 18 branches at different height levels of three trees in a 25-yr-old sugi (Cryptomeria japonica D. Don) plantation. The ø-x relationships were approximated by power-form equations, in which the exponent differed among the branches from ?0.6 to ?4.2. Leaf area (S _B) and leaf weight (W _B) of a branch were estimated on the basis of the ø-x relationship, and the dependency of specific leaf area (SLA ₀) and density (ρ ₀) of a foliage shoot segment on itsx. SLA _B value of a branch defined byS _B/W _B ranged from 27 to 80 cm² g. d.w.^?1 according to the exponent in the function of ø(x). Total leaf area (u) and leaf weight (wl) of a tree were estimated by summation ofS _B andW _B for seven sample trees. TheSLA _T value of a tree defined byu/wl ranged from 65 to 76 cm² g d.w.^?1 and increased with stem diameter at clear length (D _B). By use of the allometric equations betweenu andD _B,LAI of the plot was estimated to be 17.3 ha ha^?1 (half of the total surface area of needles). By a process similar to that used for calculatingLAI, the amount of woody tissues included in sugi foliage was evaluated to be about 10% of the stand foliage biomass.     

Proposed standard weight (Ws) equation for European perch (Perca fluviatilis Linnaeus, 1758)

Relative weight (W_r) is an important and commonly used condition index that provides a measure of the well‐being of a fish population by comparing the actual weight of a specimen with the ideal weight of a specimen of the same species and of the same length in good physiological condition, i.e. the standard weight (W_s). Two methods of calculating the standard weight are proposed in the literature: the RLP method and the EmP method. The aim of this study was to develop a standard weight equation for European perch by means of both methods, using length–weight data from 64 913 fish from 18 countries (across Europe and Oceania). The resulting equations were: log₁₀ (W_s) = ?3.1483 + 1.2663 log₁₀ (TL) + 0.4291 [log₁₀ (TL)]² for the EmP method and log₁₀ (W_s) = ?5.3493 + 3.2152 log₁₀ (TL) for the RLP method. The applicable length‐range of the two W_s equations was restricted to 80–460 mm. A further research aim was to compare the performances of RLP and EmP. The resulting quadratic EmP W_s equation did not exhibit length‐related biases, which suggests that it can be used to compute relative weight for European perch.     

Factors driving spatial and temporal variation in production and production / biomass ratio of stream‐resident brown trout (Salmo trutta) in Cantabrian streams

1. The objective was to identify the factors driving spatial and temporal variation in annual production (P_A) and turnover (production/biomass) ratio (P/B_A) of resident brown trout Salmo trutta in tributaries of the Rio Esva (Cantabrian Mountains, Asturias, north‐western Spain). We examined annual production (total production of all age‐classes over a year) (P_A) and turnover (P/B_A) ratios, in relation to year‐class production (production over the entire life time of a year‐class) (P_T) and turnover (P/B_T) ratio, over 14 years at a total of 12 sites along the length of four contrasting tributaries. In addition, we explored whether the importance of recruitment and site depth for spatial and temporal variations in year‐class production (P_T), elucidated in previous studies, extends to annual production. 2. Large spatial (among sites) and temporal (among years) variation in annual production (range 1.9–40.3 g m^?2 per year) and P/B_A ratio (range 0.76–2.4 per year) typified these populations, values reported here including all the variation reported globally for salmonids streams inhabited by one or several species. 3. Despite substantial differences among streams and sites in all production attributes, when all data were pooled, annual (P_A) and year‐class production (P_T) and annual (P/B_A) and year‐class P/B_T ratios were tightly linked. Annual (P_A) and year‐class production (P_T) were similar but not identical, i.e. P_T = 0.94 P_A, whereas the P/B_T ratios were 4 + P/B_A ratios. 4. Recruitment (Rc) and mean annual density (N_A) were major density‐dependent drivers of production and their relationships were described by simple mathematical models. While year‐class production (P_T) was determined (R² = 70.1%) by recruitment (Rc), annual production (P_A) was determined (R² = 60.3%) by mean annual density (N_A). In turn, variation in recruitment explained R² = 55.2% of variation in year‐class P/B_T ratios, the latter attaining an asymptote at P/B_T = 6 at progressively higher levels of recruitment. Similarly, variations in mean annual density (N_A) explained R² = 52.1% of variation in annual P/B_A, the latter reaching an asymptote at P/B_A = 2.1. This explained why P/B_T is equal to P/B_A plus the number of year‐classes at high but not at low densities. 5. Site depth was a major determinant of spatial (among sites) variation in production attributes. All these attributes described two‐phase trajectories with site depth, reaching a maximum at sites of intermediate depth and declining at shallower and deeper sites. As a consequence, at sites where recruitment and mean annual density reached minimum or maximum values, annual (P_A) and year‐class production (P_T) and annual (P/B_A) and year‐class P/B_T ratios also reached minimum and maximum values.     

Some biological aspects and life history strategies of Nile tilapia Oreochromis niloticus (L.) in Lake Victoria, Kenya

The life history characteristics of introduced Nile tilapia (Oreochromis niloticus L.) in Lake Victoria, including, sex ratio, fecundity, reproduction, weight‐length relationship and body condition were studied and compared with those of other populations. Samples were collected by trawling and seining in the Kenyan sector of Lake Victoria between June 1998 and December 2000. Males predominated over females (sex ratio 1.42 : 1 : 00). O. niloticus spawned throughout the year but with a peak between December and June. Length at first maturity was (mean ± SD) 30.81 ± 0.09 for females and 34.5 ± 6 0.48 for males. There was little seasonal variation in relative condition, which ranged from 0.92 to 1.05 in males and 0.94 to 1.07 in females. Gonadosomatic index (GSI) was low during the postspawning period (July to October) and high during the protracted breeding period (December and June). Fecundity ranged from 905 to 7619 oocytes for fish of 28 to 51 cm total length (TL) respectively. The relationships between fecundity (F) and total length (L), weight (W) and ovary weight (OW) were: F = 8.159L^1.53, F = 96.269W^0.4504, F = 1806 + 39.4OW. The slope b of the weight‐length relationship was 3.08–3.32 for males and 3.07–3.22 for females. Growth was allometric in both cases and was significantly different from the expected value of 3. The life history strategy of O. niloticus is discussed in context of environmental changes occurring in the lake.     

Air Displacement Plethysmography: Validation in Overweight and Obese Subjects

Objective: Patients with moderate and severe obesity, because of their physical size, often cannot be evaluated with conventional body composition measurement systems. The BOD POD air displacement plethysmography (ADP) system can accommodate a large body volume and may provide an opportunity for measuring body density (D_b) in obese subjects. D_b can be used in two‐ or three‐compartment body composition models for estimating total body fat in patients with severe obesity. The purpose of this study was to compare D_b measured by ADP to D_b measured by underwater weighing (UWW) in subjects ranging from normal weight to severely obese. Research Methods and Procedures: D_b was measured with UWW and BOD POD in 123 subjects (89 men and 34 women; age, 46.5 ± 16.9 years; BMI, 31.5 ± 7.3 kg/m²); 15, 70, and 10 subjects were overweight (25 ≤ BMI < 30 kg/m²), obese (30 ≤ BMI < 40 kg/m²), and severely obese (BMI ≥ 40 kg/m²), respectively. Results: There was a strong correlation between D_b(kilograms per liter) measured by UWW and ADP (r = 0.94, standard error of the estimate = 0.0073 kg/L, p < 0.001). Similarly, percent fat estimates from UWW and ADP using the two‐compartment Siri equation were highly correlated (r = 0.94, standard error of the estimate = 3.58%, p < 0.001). Bland‐Altman analysis showed no significant bias between D_b measured by UWW and ADP. After controlling for D_b measured by ADP, no additional between‐subject variation in D_b by UWW was accounted for by subject age, sex, or BMI. Discussion: Body density, an important physical property used in human body composition models, can be accurately measured by ADP in overweight and obese subjects.     

Length–weight relationships of wild and farmed Tor putitora from Pakistan

Length–weight relationships (W = a TL^b) were estimated for wild and farmed Tor putitora obtained from River Korang, Islamabad and Attock District, Pakistan, respectively. The results indicate, W = 0.0171 TL^2.85 for wild and W = 0.1000 TL^2.33 for farmed. Total length ranged from 18.0 to 40.2 cm for male and 31.6 to 37.0 cm for female wild Tor putitora, indicating that the fish are now much smaller. The first reference of length–weight relationships for Tor putitora is provided.     

Effect of thermal cycling and disinfection on colour stability of denture base acrylic resin

doi: 10.1111/j.1741‐2358.2012.00676.x Effect of thermal cycling and disinfection on colour stability of denture base acrylic resin Objectives: The purpose of this study was to investigate the effect of thermal cycling and disinfection on the colour change of denture base acrylic resin. Materials and Methods: Four different brands of acrylic resins were evaluated (Onda Cryl, QC 20, Classico and Lucitone). All brands were divided into four groups (n = 7) determined according to the disinfection procedure (microwave, Efferdent, 4% chlorhexidine or 1% hypochlorite). The treatments were conducted three times a week for 60 days. All specimens were thermal cycled between 5 and 55°C with 30‐s dwell times for 1000 cycles before and after disinfection. The specimens’ colour was measured with a spectrophotometer using the CIE L*a*b* system. The evaluations were conducted at baseline (B), after first thermal cycling (T₁), after disinfection (D) and after second thermal cycling (T₂). Colour differences (ΔE) were calculated between T₁ and B (T₁B), D and B (DB), and T₂ and B (T₂B) time‐points. Results: The samples submitted to disinfection by microwave and Efferdent exhibited the highest values of colour change. There were significant differences on colour change between the time‐points, except for the Lucitone acrylic resin. Conclusions: The thermal cycling and disinfection procedures significantly affected the colour stability of the samples. However, all values obtained for the acrylic resins are within acceptable clinical parameters.     

Cube law, condition factor and weight–length relationships: history, meta-analysis and recommendations

This study presents a historical review, a meta‐analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta‐analysis explores 3929 weight–length relationships of the type W = aL^b for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive‐allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as K_mean = 100aL^b?3. Relative weight W_rm = 100W/(a_mL^bm) can be used for comparing the condition of individuals across populations, where a_m is the geometric mean of a and b_m is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given.     

The influence of fertilizer nitrogen and season on the carbon-13 abundance of wheat straw

Carbon-13 abundance, expressed as δ¹³C in ‰, was measured in wheat straw grown between 1984 and 1989 on the Broadbalk Continuous Wheat Experiment at Rothamsted. In all six years, straw grown without fertilizer N contained less carbon-13 (i.e.δ¹³C was more negative) than straw grown with fertilizer, although the magnitude of this difference varied with year. In a dry year, when dry matter response to fertilizer N was relatively small, there was a large difference between the δ¹³C of straw grown with and without N. Conversely, in a wet year, when there was a marked response to N, there was little difference in the isotopic composition of N-fertilized and unfertilized straw. Over the six years, the difference between the δ¹³C value of straw grown with and without nitrogen (D ¹³C, in ‰) was related to drought, measured as the calculated soil water deficit on 15 July (W_j, in mm), by the equation D ¹³C=−0.299+0.01034 W_j (r=0.87). H Lambers Section editor     

Allometric relationships for estimating the aboveground phytomass and leaf area of mangrove Kandelia candel (L.) Druce trees in the Manko Wetland, Okinawa Island, Japan

Allometric relationships for estimating the phytomass of aboveground organs (stem, branches, leaves and their sum) and the leaf area in the mangrove Kandelia candel (L.) Druce were investigated. The variable D_0.1²H (D_0.1 stem diameter at a height of H/10, H tree height) showed better accuracy of estimation than D² (D, DBH) or D²H. A moderate relationship was found when the branch weight, leaf weight and leaf area were plotted against D_B² (D_B stem diameter at a height of clear bole length). A strong linear relationship was found between leaf area and leaf weight (R²=0.979). The aboveground weight (w_T) showed a strong relationship when plotted against D_0.1²H (R²=0.958), but very weak relationships were obtained against D² (R²=0.300) and D²H (R²=0.316). The w_T also showed a proportional relationship (R²=0.978) to D_0.1²H with a proportional constant of 0.04117 kg cm^–2 m^–1 (R²=0.978). Taking into account the allometric relationships of the weight of aboveground organs or leaf area per tree to different dimensions, such as D², D²H, D_B² and D_0.1²H, a standard procedure for estimating the biomass and leaf area index in the K. candel stand, including the shorter trees, is proposed.     

Length–weight and length–length relationships for some Yangtze River fishes in Tian‐e‐zhou Oxbow,China

Length–weight and length–length relationships are reported for 32 fish species belonging to seven families and 26 genera from the Tian‐e‐zhou Oxbow in the middle reach of Yangtze River, near Shishou City, China. The weight (W) ‐ length (L) relationships were estimated using the logarithmic form of the equation W = aL^b. The exponent b varied from 2.60 to 3.65 (mean ± SE: 3.12 ± 0.25). The 14 weight–length relationships, 13 length–length relationships, and seven maximum lengths are presented to FishBase for the first time.     

Weight–length relationships for 46 fish species of the Portuguese west coast

Weight–length (W–L) relationships were estimated for 46 species of fish captured off the western Portuguese coast between April 1994 and September 1995. The best‐represented family was Scyliorhinidae (2677 fishes), followed by Gadidae (1871), Sparidae (1682) and Merlucciidae (1108). The estimates for the parameter b of the W–L relationship (W = aL^b) ranged between 2.171 and 3.873, with a median of 3.124. Significant variations in b were found at seasonal level for striped red mullet (Mullus surmuletus), axillary seabream (Pagellus acarne), greater weever (Trachinus draco) and the sardine (Sardina pilchardus), at the regional level for Atlantic mackerel (Scomber scombrus), and between sexes for the small‐spotted dogfish (Scyliorhinus canicula).     

Effects of 1,25(OH)2D3 and vitamin D receptor on peripheral CD4+/CD8+ double‐positive T lymphocytes in a mouse model of systemic lupus erythematosus

This study aims to explore effects of 1,25(OH)₂D₃ and vitamin D receptor (VDR) on peripheral CD4⁺/CD8⁺ double‐positive (DP) T lymphocytes in systemic lupus erythematosus (SLE). MRL‐LPr/LPr mice with SLE (n = 20) and normal MRL mice (n = 20) were assigned into the control group (normal mice, without feeding with 1,25(OH)₂D₃), the 1,25(OH)₂D₃ group (SLE mice, feeding with 1,25(OH)₂D₃), the VDR‐knock‐in + 1,25(OH)₂D₃ group (SLE mice, VDR‐knock‐in, feeding with 1,25(OH)₂D₃) and the VDR‐knockout group (normal mice, VDR‐knockout, without feeding with 1,25(OH)₂D₃) (n = 10 per group). Levels of T lymphocytes were measured by flow cytometry. The mRNA and proteins expressions of inflammatory factors were measured by qRT‐PCR and ELISA. Extracellular signal‐regulated kinase‐1/2 (ERK1/2) expression was measured by Western blotting. Compared with normal mice, SLE mice showed reduced levels of CD4⁺, CD4⁺/CD8⁺ ratio, and DP lymphocytes. The levels of SLE‐related indicators all increased significantly, followed with severe skin ulcers and urinary system infection. With the increase in time, skin ulcers and urinary system infection were significantly improved, levels of CD4⁺, CD4⁺/CD8⁺ ratio, and DP lymphocytes increased, and levels of SLE‐related indicators all decreased in the 1,25(OH)₂D₃ group. There were no significant changes in bioindicators in the control and the VDR‐knock‐in + 1,25(OH)₂D₃ groups. The symptoms of SLE gradually occurred in the VDR‐knockout group. This study demonstrates that VDR and 1,25(OH)₂D₃ could elevate CD4⁺/CD8⁺ DP T lymphocytes and reduce expressions of inflammatory factors, thus inhibiting the development and progression of SLE.     

Canopy transpiration in a chronosequence of Central Siberian pine forests

Tree transpiration was measured in 28, 67, 204 and 383‐y‐old uniform stands and in a multicohort stand (140–430 y) of Pinus sylvestris ssp. sibirica Lebed. in Central Siberia during August 1995. In addition transpiration of three codominant trees was monitored for two years in a 130‐y‐old stand. All stands established after fire. Leaf area index (LAI) ranged between 0.6 (28‐y‐old stand) and 1.6 for stands older than 67‐y. Stand xylem area at 1.3 m height increased from 4 cm² m^?2 (28‐y) to 11.5 cm² m^?2 (67‐y) and decreased again to 7 cm² m^?2 in old stands. Above‐ground living biomass increased from 1.5 kg dry weight m^?2 (28‐y) to 14 kg dry weight m^?2 (383‐y). Day‐to‐day variation of tree transpiration in summer was dependent on net radiation, vapour pressure deficit, and soil water stress. Tree‐to‐tree variation of xylem flux was small and increased with heterogeneity in canopy structure. Maximum rates of xylem flux density followed the course of net radiation from mid April when a constant level of maximum rates was reached until mid September when low temperatures and light strongly reduced flux density. Maximum sap flux density (60 g m^?2 s^?1) and canopy transpiration (1.5 mm d^?1) were reached in the 67‐y stand. Average canopy transpiration of all age classes was 0.72 ± 0.3 mm d^?1. Canopy transpiration (E) was not correlated with LAI but related to stand sapwood area SA (E = ? 0.02 + 1.15SA R²) which was determined by stand density and tree sapwood area.     

Is maximum sustainable yield independent of body size for mammals (and others)?

Summary Provided carrying capacity (K) for non-primate mammals scales with the –0.75 power of adult body weight (W), MSY (in weight) should be approximately one-sixth ofC, whereC is defined byK =CW ^–0.75.     

Synthesis and luminescence properties of Ca3Ga2Si3O12:RE3+ (RE = Eu/Tb) powder phosphors

Rare earth ions (Eu³⁺ or Tb³⁺)‐activated Ca₃ Ga₂ Si₃O₁₂ (CaGaSi) phosphors were synthesized by using a sol–gel method. Photoluminescence spectra of Eu³⁺:CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions (⁵D₀ → ⁷F₀, ⁷F_1, ⁷F₂, ⁷F₃ and ⁷F₄), respectively, with an excitation wavelength of λ_exci = 392 nm. Among these, the transition ⁵D₀ → ⁷F₂ (612 nm) displayed bright red emission. In the case of Tb³⁺:CaGaSi phosphors, four emission bands were observed at 488 (⁵D₄ → ⁷F₆), 543 (⁵D₄ → ⁷F₅), 584 (⁵D₄ → ⁷F₄) and 614 nm (⁵D₄ → ⁷F₃) from the measurement of PL spectra with λ_exci = 376 nm. Among these, the transition ⁵D₄ → ⁷F₅ at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X‐ray diffraction (XRD), scanning electron microscopy (SEM) and energy‐dispersive X‐ray analysis (EDAX) results. Copyright © 2011 John Wiley & Sons, Ltd.     

Life history traits of Aphanius ginaonis Holly, 1929 (Cyprinodontidae) and potential risks of extinction in the Geno hot spring (Iran) population

This study presents some traits of the Aphanius ginaonis life history in the Geno hot spring and explains the potential risks of its extinction. Sampling was from March 2009 to February 2010. A total of 61 males and 71 females were measured (total length) and weighed, with data on reproductive biometry also taken. Growth parameters were determined in addition to weight–length relationships: W (t) = 0.012TL^3.42, R² = 0.96 for females and W (t) = 0.0101TL^3.38, R² = 0.94 for males. A. ginaonis females showed an asymptotic total length (TL_∞) of 53.03 mm; the growth coefficient, K (year^?1) 0.15, t₀ (year) 1.01; and natural mortality coefficient M (year^?1) 0.62. In males the value for TL_∞ was 48.83 mm; for K (year^?1) 0.2, t₀ (year) 0.44; and M (year^?1) 0.49. The relationship between absolute fecundity and fish size (total length, body weight or age) showed a strong correlation to body weight. The A. ginaonis population is threatened with extinction – and a co‐management in cooperation with the local population for strong protection measures is urgently needed.     

Relationship between Number of Eggs,Brood Weight,and Female Body Weight in Crustacea

Relationships between number of eggs (N_g), brood weight (W_g), and body length (L) and weight (W) of females were studied for 16 orders and suborders of Crustacea. The study was based on the authors' observations in the inland waters of the European USSR, in the coastal regions of the fareastern and northern seas and data from V. V. KUZNETSOV (preserved in archives). An extensive literature was also used. The equations describing the relationships (N_g=f(L) and W_g=f(W) are calculated for some species and high taxons. On the average for the superclass (excluding the order Notostraca) the W_g/W ratio appeared to be 0.16. This ratio is markedly different for species of Notostraca. It is supposed that this difference is due to the high metabolic rate of Notostraca.     

Relationship between surplus energy and body weight in fish populations

This paper theoretically analyses the relationship between surplus energy, which is available for either somatic growth or reproduction, and body weight. From the data of metabolism and growth of the biwamasu, Oncorhynchus rhodurus, obtained by Miura et al., a Bernoulli's differential equation is induced to represent the relationship between body weight and the sum of surplus energy and active metabolic rate. Solving this equation gives the amount of surplus energy, f(W_x), as follows:f(W_x) = (αW_x^1−γ+β^1−γ)^1/(1−γ)−W_x, in which α, β and γ are constants and W_x is body weight at age x. The function is applied to ten fish populations and consequently it is found to be useful for a wider age range and a wider variety of fishes than the conventional function.