Empirical modelling of tensile strength of woven fabrics

Aesthetic properties of fabrics have been considered as the most important fabric attribute for years. However, recently there has been a paradigm shift in the domain of textile material applications and consequently more emphasis is now being given on the mechanical and functional properties of fabrics rather than its aesthetic appeal. Moreover, in certain woven fabrics used for technical applications, strength is a decisive quality parameter. In this work, tensile strength of plain woven fabrics has been predicted by using two empirical modelling methods namely artificial neural network (ANN) and linear regression. Warp yarn strength, warp yarn elongation, ends per inch (EPI), picks per inch (PPI) and weft count (Ne) were used as input parameters. Both the models were able to predict the fabric strength with reasonably good precision although ANN model demonstrated higher prediction accuracy and generalization ability than the regression model. The warp yarn strength and EPI were found to be the two most significant factors influencing fabric strength in warp direction.     

Modulation of diversity by grazing and mowing in native tallgrass prairie

Species diversity has declined in ecosystems worldwide as a result of habitat fragmentation, eutrophication, and land-use change. If such decline is to be halted ecological mechanisms that restore or maintain biodiversity are needed. Two long-term field experiments were performed in native grassland to assess the effects of fire, nitrogen addition, and grazing or mowing on plant species diversity. In one experiment, richness declined on burned and fertilized treatments, whereas mowing maintained diversity under these conditions. In the second experiment, loss of species diversity due to frequent burning was reversed by bison, a keystone herbivore in North American grasslands. Thus, mowing or the reestablishment of grazing in anthropogenically stressed grasslands enhanced biodiversity.     

Reproduction,growth and stress response in adult red sea bream,Pagrus major (Temminck & Schlegel) exposed to different photoperiods at spawning season

Adult red sea bream, Pagrus major (body weight, 1.0–2.0 kg) was exposed to three photoperiods [12 h light:12 h dark (12L:12D), 16 h light:8 h dark (16L:8D) and 24 h light:0 h dark (24L:0D)] from 2 months before spawning till the end of the spawning season to investigate growth, spawning and stress response. During the spawning season, tanks were checked every morning for spawned eggs. The growth performance in fish under 24L:0D was stimulated with significantly higher feed intake than those under other photoperiods (P<0.05). The number of eggs and gonadal histology confirmed that three and five females out of six in each of duplicate tanks of the 16L:8D treatment spawned. In contrast, only two out of six females in one tank of the 24L:0D treatment spawned, and no spawns were observed in the 12L:12D treatment. At the end of the spawning period, both 17β‐estradiol and testosterone levels were significantly higher in fish exposed to 16L:8D followed by 12L:12D and 24L:0D photoperiods (P<0.05). Photoperiod manipulation did not cause significant stress response in fish (P>0.05). The results suggest that stimulating the growth performance of red sea bream at reproductive stage with a 24L:0D photoperiod is possible if the fish are subjected to this photoperiod long before the onset of the spawning season.     

Effect of rotifer enrichment with herbal extracts on growth and resistance of red sea bream,Pagrus major (Temminck & Schlegel) larvae against Vibrio anguillarum

The effects of the dietary medicinal herbs Massa medicata, Crataegi fructus (Cf), Artemisia capillaries, Cnidium officinale and their mixture (HM), on growth and resistance against Vibrio anguillarum were examined using larval red sea bream, Pagrus major. The methanol extracts of Cf and HM inhibited the proliferation of seven infectious bacterial strains including the genera Aeromonas, Edwasiella, Photobavterium, Pseudomonas and Vibrio. Rotifers enriched with emulsified bonito oil containing extracts of Cf and HM lowered the bacterial counts in their body on TCBS medium for the genus Vibrio in comparison with rotifers enriched by emulsified bonito oil alone. Although statistically not significant, larvae fed rotifer fortified with Cf from 3 to 20 days after hatching showed the best growth and final body weight followed by those given rotifer with HM and control enrichment. However, final body length of larvae fed rotifer with Cf was significantly larger than larvae fed on rotifers enriched with other herb extracts. After a challenge test with V. anguillarum, survival of larvae fed rotifer with Cf and HM was significantly higher than for the control treatment. These results revealed that Cf and HM in rotifer is useful to promote growth and resistance against V. anguillarum in red sea bream larvae, providing a new technology for mass production of disease‐resistant fry and fingerlings.     

Intermittent drainage in paddy soil: ecosystem carbon budget and global warming potential

Intermittent drainage of rice fields alters soil redox potential and contributes to the reduction of CH₄ emission and thus may reduce net global warming potential (GWP) during rice cultivation. Incorporation of green biomass helps maintaining soil organic matter, but may increase CH₄ emission. We investigated net ecosystem carbon budget (NECB) and net GWP under two water management regimes—continuous flooding and intermittent drainage—having four biomass incorporation levels (0, 3, 6 and 12 Mg ha^?1). Water management and biomass incorporation level demonstrated significant (P < 0.05) interaction effect on the NECB and GWP. Intermittent drainage decreased the NECB by ca. 6–46 % than continuous flooding under same rates of cover crop biomass (CCB) incorporation. Moreover, intermittent drainage reduced seasonal CH₄–C fluxes by ca. 54–58 % and net GWP by 35–58 % compared to continuous flooding. There was also no significant reduction in rice yield because of intermittent drainage under similar CCB. This implies that incorporation of 3 Mg ha^?1 CCB and intermittent drainage could be a good option for reducing net GWP and higher grain yield.     

Disturbance increases negative spatial autocorrelation in species diversity

Context

Ecological processes that shape diversity and spatial pattern of ecological communities are often altered by disturbance. Spatial patterns (spatial autocorrelation) in species diversity are thus expected to change with disturbance.

Objective

When examining spatial patterns, ecologists traditionally lump positive and negative spatial autocorrelation into the overall spatial autocorrelation. By contrast, here we aim to understand disturbance effects on both positive and negative spatial autocorrelation of species richness and evenness, which may be related to environmental filtering and restricted dispersal, and to competition, respectively.

Methods

For 8 years, we monitored the spatial autocorrelation in species richness and evenness of riparian plant communities in both uncut control and experimentally clearcut sites in the boreal forest of Alberta, Canada. The overall spatial autocorrelation for each of these two indices of diversity was separately decomposed into the components of positive and negative spatial autocorrelations through eigendecomposition of the spatial weighting matrix.

Results

Negative spatial autocorrelation in richness and evenness were more pronounced in the clearcut than uncut sites, although positive spatial autocorrelations in all indices of diversity remained unchanged. Effect of disturbance was not detected on the overall spatial autocorrelation.

Conclusions

Disturbance increases negative spatial autocorrelation in species richness and evenness, with a stronger increase in evenness than richness, which underscores the importance of competition in structuring post-disturbance riparian communities. Our results also highlight the need for assessing positive and negative spatial autocorrelation and different aspects of diversity separately in understanding disturbance effects on the spatial pattern, or identifying processes from patterns.

     

The effects of supplemental threonine on performance,carcass characteristics,immune response and gut health of broilers in subtropics during pre‐starter and starter period

Three hundred thirty‐day‐old unsexed commercial broiler chicks (Vencobb‐400) with initial average body weight of 44.04 ± 0.42 g were allocated into five experimental groups, in a completely randomized design (CRD) with 21‐day experiment. Groups were formed according to dose of supplemental L‐threonine in various rations i.e., 100% NRC specification, 100% threonine of Vencobb‐400 strain specification, 110% threonine of Vencobb‐400 strain specification, 120% of threonine of Vencobb‐400 strain specification and 130% threonine of Vencobb‐400 strain specification. Average daily feed intake (ADFI), average daily body weight gain (ADG), cumulative feed conversion ratio (CFCR), carcass characteristics, immune response, intestinal morphometry and biochemical profile were studied. The ADFI and ADG increased linearly and quadratically as dietary threonine levels were increased. However, the CFCR did not differ (p ? 0.05) among the groups. Though the carcass weight and drumstick yield did not differ (p ? 0.05) among the groups, the relative breast yield increased linearly (p = 0.007). The relative dressing yield and relative thigh weight increased linearly (p = 0.05 and p = 0.03, respectively). The relative weight of immune organs like bursa and thymus increased linearly. The mean total serum immunoglobulin, ND‐ELISA titre and the mean lymphocyte proliferation response index increased linearly, whereas mean phagocytic activity index of neutrophil increased linearly (p < 0.001) and quadratically (p = 0.001). The mean villus height (VH), crypt depth (CD), villus surface area and mean goblet cell number/villus increased linearly and quadratically, whereas the villus width (VW) and goblet cell density increased quadratically. The serum glucose increased linearly (p = 0.001), whereas serum total protein concentration and serum globulin level increased both linearly and quadratically. The albumin: globulin ratio tended to decrease linearly. There was a significant decrease (p < 0.05) in serum cholesterol and VLDL cholesterol level. However, a linear increment (p = 0.04) in the blood serum HDL cholesterol level with a linear reduction (p = 0.01) in the blood serum LDL cholesterol was noticed.     

Comparative analysis of some selected macronutrients of soil in orange orchard and degraded forests in Chittagong Hill Tracts,Bangladesh

Status of organic carbon （C）, total nitrogen （N）, available potassium （K）, calcium （Ca） and phosphorus （P） in three different depths （0-5 cm, 5-15 cm and 15-30 cm） on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill. Tracts （CHTs） were evaluated and compared with those in degraded bush forests, through digging three profiles in each land use. The content of all the five nutrients was found to be higher in the soil of orange orchard than in the soil of forest. But the variation was not consistent for both the slopes. The content varied depth wise also, having the highest value in surface soil in case of both the land uses on both the slopes. A mean available K content was significantly higher in orange orchard than in forest on 55% slope, while it was lower on 35% slope. Surface soil contained the nutrients of K and Ca with the amount of 0.2905-mg·g^-1 soil and 3.025-mg·g^-1 soil respectively in the orchard, while 0.1934-mg·g^-1 soil and 1.6083-mg·g^-1 soil were respectively in the forest. Organic carbon and total nitrogen were found more or less similar in surface soil on both the land uses showing a slight difference. Available P was found only in orange orchard, and in forest it was too little in amount to detect by the spectrophotometer. The degraded forests were poor in nutrient content due to high rate of soil erosion, which would be possible to be improved by bringing it under tree cover as proved by the adaptation of orange orchard there.     

Follicle and fibre characteristics of Indian pashmina goats

The hair follicle and fibre characteristics of Cheghu and Changthangi pashmina goats are reported. The average numbers of primary follicles mm-2 were 6.80, 5.20, 5.67 and 4.00; secondary follicles 42.40, 27.10, 38.56 and 29.67; secondary to primary follicle ratio 6.46, 5.78, 6.79 and 7.60; total follicle population 49.20, 32.30, 44.22 and 33.67 in Cheghu females, Cheghu males, Changthangi females and Changthangi males, respectively. The breed difference was not significant for any of these traits, but the sex difference was significant for a number of secondary follicles and total density. Study of fleece characteristics of Cheghu goats in a 1 cm2 area of five body regions, namely, neck, shoulder, mid-side, flank and abdomen, showed that females had finer fibres (12.06 to 12.12 micron) than males (13.04 to 13.64 micron) in all regions. The pashmina length, pashmina diameter and fibre thickness ratio were significantly different between sexes and between body regions but hair/pashmina ratio and pashmina yield were significant for sex and body regions, respectively.