Futures of inland aquatic agricultural systems and implications for fish agri-food systems in southern Africa

The CGIAR Research Program on Aquatic Agricultural Systems (AAS) is collaborating with partners to develop and implement a foresight-based engagement with diverse stakeholders linked to aquatic agricultural systems. The program’s aim is to understand the implications of current drivers of change for fish agri-food systems, and consequently food and nutrition security, in Africa, Asia and the Pacific. Partners include the Global Forum on Agricultural Research (GFAR), the Forum for Agricultural Research in Africa (FARA) and the African Union’s New Partnership for Africa’s Development (AU-NEPAD). A key part of the program was a participatory scenario-building workshop held in July 2015 under the theme of "futures of aquatic agricultural systems and implications for fish agri-food systems in southern Africa." The objectives for the workshop were (i) to engage local stakeholders in exploring plausible futures of aquatic agricultural systems, and (ii) to broker and catalyze collaborative plans of action based on the foresight analysis. This report presents technical findings from the workshop. The CGIAR Research Program on Aquatic Agricultural Systems (AAS) is collaborating with partners to develop and implement a foresight-based engagement with diverse stakeholders linked to aquatic agricultural systems. The program’s aim is to understand the implications of current drivers of change for fish agri-food systems, and consequently food and nutrition security, in Africa, Asia and the Pacific. Partners include the Global Forum on Agricultural Research (GFAR), the Forum for Agricultural Research in Africa (FARA) and the African Union’s New Partnership for Africa’s Development (AU-NEPAD). A key part of the program was a participatory scenario-building workshop held in July 2015 under the theme of "futures of aquatic agricultural systems and implications for fish agri-food systems in southern Africa." The objectives for the workshop were (i) to engage local stakeholders in exploring plausible futures of aquatic agricultural systems, and (ii) to broker and catalyze collaborative plans of action based on the foresight analysis. This report presents technical findings from the workshop.

Guidelines for evaluating the ease of reconfiguration of manufacturing systems

This paper presents guidelines for evaluating the ease of reconfiguration of manufacturing systems. Based reconfigurability measurement tools proposed in the past [1], [2]and a reconfiguration process model, the paper proposes a method that can be used to assess different system characteristics. After the guideline is presented, an example of how the method can be applied to a batch processing system is given. It is found that the proposed method can be applied to batch processing systems based on ISA S88 batch server commercial software. ©2008 IEEE.

Responses to seasonal changes in nutrient quality and patchiness of food in a multigroup community of Tibetan macaques at Mt. Emei

Provisioning along pedestrian trails by tourists much increased the nutrient quality and patchiness of food (NqPF)for Tibetan macaques (Macaca thibetana) at Mt Emei in spring and summer. In the habitat at a temperate-subtropical transition zone, the mncaque's NqPF could be ordered in a decreasing rank from spring summer to autumn to winter With the aid of a radio-tracking system, I collected ranging data on a multigroup community in three 70-day periods representing the different seasons in 1991-92, Rank-order correlation on the data show that with the decline of NqPF; the groups tended to increase days away from the trail, their effective range size (ERS) their exclusive area (EA) and the number of days spent in the EA, and reduced their group/community density and the ratio of the overlapped range to the seasonal range (ROR). In icy/snowy winter; the macaques searched for mature leaves slowly and carefully in the largest seasonal range with a considerable portion that was nor used in other seasons. Of the responses, the ROR decreased with the reduction in group/community density; and the ERS was the function of both group size (+) and intergroup rank (-) when favorite food was highly clumped. All above responses were clearly bound to maximize foraging effectiveness and minimize energy expenditure, and their integration in term of changes in time and space leads to better understanding macaque ecological adaptability. Based on this study and previous work on behavioral and physiological factors, I suggest a unifying theory of intergroup interactions. Ir! addition, as the rate of behavioral interactions,was also related to the group density, I Waser's (1976) gas model probably applies to behavioral, as well as spatial, data on intergroup interactions.

Toward automated generation of parametric BIMs based on hybrid video and laser scanning data

Only very few constructed facilities today have a complete record of as-built information. Despite the growing use of Building Information Modelling and the improvement in as-built records, several more years will be required before guidelines that require as-built data modelling will be implemented for the majority of constructed facilities, and this will still not address the stock of existing buildings. A technical solution for scanning buildings and compiling Building Information Models is needed. However, this is a multidisciplinary problem, requiring expertise in scanning, computer vision and videogrammetry, machine learning, and parametric object modelling. This paper outlines the technical approach proposed by a consortium of researchers that has gathered to tackle the ambitious goal of automating as-built modelling as far as possible. The top level framework of the proposed solution is presented, and each process, input and output is explained, along with the steps needed to validate them. Preliminary experiments on the earlier stages (i.e. processes) of the framework proposed are conducted and results are shown; the work toward implementation of the remainder is ongoing.

Evaluation of Setup Procedures on Mobile Devices Based on Users’ Initial Experience

Users’ initial perceptions of their competence are key motivational factors for further use. However, initial tasks on a mobile operating system (OS) require setup procedures, which are currently largely inconsistent, do not provide users with clear, visible and immediate feedback on their actions, and require significant adjustment time for first-time users. This paper reports on a study with ten users, carried out to better understand how both prior experience and initial interaction with two touchscreen mobile interfaces (Apple iOS and Google Android) affected setup task performance and motivation. The results show that the reactions to setup on mobile interfaces appear to be partially dependent on which device was experienced first. Initial experience with lower-complexity devices improves performance on higher-complexity devices, but not vice versa. Based on these results, the paper proposes six guidelines for designers to design more intuitive and motivating user interfaces (UI) for setup procedures. The preliminary results indicate that these guidelines can contribute to the design of more inclusive mobile platforms and further work to validate these findings is proposed.

Design guidelines for granular particles in a conical centrifugal filter

Essential design criteria for successful drying of granular particles in a conical continuous centrifugal filter are developed in a dimensionless fashion. Four criteria are considered: minimum flow thickness (to ensure sliding bulk flow rather than particulate flow), desaturation position, output dryness and basket failure. The criteria are based on idealised physical models of the machine operation and are written explicitly as functions of the basket size lout, spin velocity Ω and input flow rate of powder Qp. The separation of sucrose crystals from liquid molasses is taken as a case study and the successful regime of potential operating points (lout, Ω) is plotted for a wide range of selected values of flow rate Qp. Analytical expressions are given for minimum and maximum values of the three independent parameters (lout, Ω, Qp) as a function of the slurry and basket properties. The viable operating regime for a conical centrifugal filter is thereby obtained as a function of the slurry and basket properties. © 2012 The Institution of Chemical Engineers.

A printable optical time-temperature integrator based on shape memory in a chiral nematic polymer network

An optical and irreversible temperature sensor (e.g., a time-temperature integrator) is reported based on a mechanically embossed chiral-nematic polymer network. The polymer consists of a chemical and a physical (hydrogen-bonded) network and has a reflection band in the visible wavelength range. The sensors are produced by mechanical embossing at elevated temperatures. A relative large compressive deformation (up to 10%) is obtained inducing a shift to shorter wavelength of the reflection band (>30 nm). After embossing, a temperature sensor is obtained that exhibits an irreversible optical response. A permanent color shift to longer wavelengths (red) is observed upon heating of the polymer material to temperatures above the glass transition temperature. It is illustrated that the observed permanent color shift is related to shape memory in the polymer material. The films can be printed on a foil, thus showing that these sensors are potentially interesting as time-temperature integrators for applications in food and pharmaceutical products. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contributions of Pelagic and Benthic Dietary Sources to Freshwater Mussels: Evidence from Stable Carbon Isotope Analysis

In Gonghu Bay of Lake Taihu, tissue of five mussel species showed delta C-13 values similar to or slightly below that of pelagic suspended particulate organic matter (SPOM). This indicated that mussels in this area either fed non-selectively and so reflected available carbon in the pelagic habitat or selected for phytoplankton. The situation was the same for Anodonta woodiana woodiana and Cristaria plicata in Meiliang Bay; however, for the remaining three species, Hyriopsis cumingii, Arconaia lanceolata, and Lamprotula rochechouarti, tissue had intermediate delta C-13 values, falling between those for pelagic SPOM and benthic sediment organic matter (SOM), suggesting a possible preferential selection of phytoplankton from the pelagic SPOM but more likely reflecting local differences in pelagic SPOM and benthic SOM composition and available organic carbon sources. The mixing model showed that pelagic SPOM accounted for over 98% of carbon incorporated by all mussels in Gonghu Bay and two mussels in Meiliang Bay, suggesting the dietary importance of pelagic food sources for mussels. Less than 50% of the assimilation in H. cumingii, A. lanceolata, and L. rochechouarti came from the pelagic carbon sources in Meiliang Bay, which suggested that these species consumed a mix of benthic and pelagic derived carbon sources.

Food Consumption by In Situ Pen-Cultured Planktivorous Fishes and Effects on an Algal Bloom in Lake Taihu, China

Silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) were used as a new pen-cultureed biomanipulation technique to control algal blooms in Meiliang Bay of Lake Taihu. In order to evaluate the capacity of these two fishes to decrease algal blooms, diel feeding samplings were carried out in May (without algal blooms) and September (with algal blooms) in 2005. Based on estimated food consumption by the Elliott-Persson model, silver carp increased daily food consumption from 2.07 g dry weight per 100 g wet body weight in May before the outbreak of algal blooms to 4.98 g dry weight per 100 g wet body weight in September during algal blooms outbreak. However, no obvious variation of food consumption was observed in bighead carp during the study period. This species 1.88 and 1.54 g dry weight of plankton per 100 g wet body weight in May and September, respectively. Silver carp had a higher feeding capacity for plankton than bighead carp. Biotic factors (i.e., fish size and conspecific competition with natural species in the lake) may affect the feeding behaviors of both carps as well as seasonal variation of plankton communities in the pen.

Food web of benthic macro invertebrates in a large Yangtze River-connected lake: the role of flood disturbance

This Study was conducted in Lake Dongtinghu, a large river-connected lake on the Yangtze River flood-plain, China. Our goal was to determine trophic relationships among benthic macroinvertebrates, as well as the effects of flood disturbance on the benthic food web of a river-connected lake. Macroinvertebrates in the lake fed mainly on detritus and plankton (both zooplankton and phytoplankton). Food web Structure in Lake Dongtinghu was characterized by molluscs as the dominant group, low connectance, high level of omnivory. based oil detritus and primary production, and most ingestion concentrating on a few links. Our analyses showed that flood disturbance is an important factor affecting the benthic food web in Lake Dongtinghu. The numbers of species and functional feeding groups (FFGs), and the density and biomass of macroinvertebrates decreased significantly during flooding. Connectance was higher during the flood season than in other seasons, indicating that floods have a strong effect on connectance in this Yangtze River-connected lake. Flood effects on the benthic web were also evident in the decrease of niche overlaps within and anion, FFGs. Our results provide useful information regarding biodiversity conservation on the Yangtze floodplain. Reconstructing and maintaining natural and regular flow regimes between Yangtze lakes and the river is essential for restoration of macroinvertebrates on the floodplain.

Dietary phosphorus requirement of juvenile black seabream, Sparus macrocephalus

A growth trial was conducted to estimate the optimum requirement of dietary available phosphorus (P) for black seabream (Sparus macrocephalus) in indoor net cages (1.5x1.0x1.0 m). Triplicate groups of black seabream (11.45 +/- 0.02 g) were fed diets containing graded levels (0.18, 0.36, 0.54, 0.72, 0.89 and 1.07%) of available P to satiation for 8 weeks. The basal diet (diet 1), containing 0.18% available P, was supplemented with graded levels of monosodium phosphate (NaH2PO4 2H(2)O) to formulate five experimental diets. The fish were fed twice daily (08:00 h and 16:00 h) and reared in seawater (salinity, 26-29 g l(-1)) at a temperature of 28 +/- 1 degrees C. Dissolved oxygen during the experiment was above 5 mg l(-1). The specific growth rate (SGR), weight gain (WG), feed efficiency (FE) and protein efficiency ratio (PER) were all significantly improved by dietary phosphorus up to 0.54% (P<0.05) and then leveled off beyond this level. Hepatosomatic index (HSI) was inversely correlated with dietary phosphorus levels (P< 0.05). Efficiency of P utilization stabled in fish fed diets containing 0.18%-0.54% available P and then decreased dramatically with further supplementation of dietary phosphorus. Body composition analysis showed that the whole-body lipid, ash, calcium and phosphorus contents were all significantly affected by dietary available P concentration (P<0.05), however, no significance were found in whole-body calcium/phosphorus (Ca/P) ratios among all the treatments (P>0.05). Dietary phosphorus levels also affected the mineralization of vertebrae, skin and scale (P<0.05). Ca/P ratios in vertebrae and scale were not influenced by dietary P supplementation, while skin Ca/P ratio increased statistically with dietary available P levels (quadratic effect, P<0.001). The blood chemistry analysis showed that dietary available P had distinct effects on enzyme activities of alkaline phosphatase (ALP) and plasma lysozyme (LSZ), as well as contents of triacyglycerol (TG) and total cholesterol (T-CHO) (P<0.05). Broken-line analysis showed maximum weight gain (WG) was obtained at dietary available P concentrations of 0.55%. Quadratic analysis based on P contents in whole fish, vertebrae or scale indicated that the requirements were 0.81, 0.87 and 0.88%, respectively. Signs of phosphorus deficiency were characterized by poor growth, slightly reduced mineralization and an increase in body lipid content. (C) 2008 Published by Elsevier B.V.

A novel chemiluminescent immunoassay for microcystin (MC) detection based on gold nanoparticles label and its application to MC analysis in aquatic environmental samples

A novel chemiluminescent immunoassay method based on gold nanoparticles was developed for the detection of microcystins (MCs). The immunoassay included three main steps: indirect competitive immunoreaction, oxidative dissolution of gold nanoparticles, and indirect determination for MCs with Au3+-catalysed luminol chemiluminesent system. The method has a wide working range (0.05-10 mu g L-1, r(2) = 0.9914), the limit of detection was determined to be 0.024 mu g L-1, which is much lower than the World Health Organization's proposed guidelines (1 mu g L-1) for drinking-water. The proposed method was applied to MC analysis in natural water and fish tissue samples, and most results in the proposed method were in agreement with the conventional indirect competitive enzyme-linked immunosorbent assay method, which indicated that the new chemiluminescent immunoassay was sensitive, reliable, and suitable for MC analysis in natural water and fish tissue samples.

Impact of environmental and innate factors on the food habit of Chinese perch Siniperca chuatsi (Basilewsky) (Percichthyidae)

Laboratory and field investigations were conducted to study the food habit of Chinese perch Siniperca chuatsi (Basilewsky) from first feeding through adult stage. Only fish larvae were consumed by Chinese perch larvae (2-21 days from hatching), and the presence of zooplankton did not have any significant effect on their survival rate. The ability of Chinese perch to feed on zooplankton is clearly limited by some innate factor. Instead of gill rakers, Chinese perch larvae have well-developed sharp teeth at the first feeding stage, and are well adapted to the piscivorous feeding habit unique to the larvae of Chinese perch, e.g. they bite and ingest the tails of other fish larvae. At the first feeding stage (2 days from hatching), daily rations were both very low, either in light or complete darkness. Although early-staged Chinese perch larvae (7-17 days from hatching) could feed in complete darkness, their daily rations were always significantly higher in light than in complete darkness. Late-staged Chinese perch larvae (21 days from hatching) were able to feed in complete darkness as well as in light, similar to the case of Chinese perch yearlings. Chinese perch yearlings (total length, 14-16 cm) consumed prey fish only and refused shrimp when visual cues were available (in light), but they consumed both prey when visual cues were not available (in complete darkness), suggesting that prey consumption by Chinese perch yearlings is affected by their sensory modality in predation. Both prey were found in the stomachs of similar-sized Chinese perch (total length, 14-32 cm) from their natural habitat, suggesting that shrimp are consumed by Chinese perch at night. Prey selection of Chinese perch with a length >38 cm, which consumed only fish in the field, appears to be based upon prey size instead of prey type. These results suggest that although environmental factors (e.g. light intensity) affect prey detection by Chinese perch, this fish is anatomically and behaviourally predisposed to prey on live fish from first feeding. This makes it a difficult fish to cultivate using conventional feeds.

Effect of dietary carbohydrate-to-lipid ratios on growth and feed utilization in Chinese longsnout catfish (Leiocassis longirostris Gunther)

An 8-week growth trial was carried out in a semi-recirculation system at 26 +/- 0.5 degrees C to investigate the optimal dietary carbohydrate-to-lipid (CHO:L) ratio for carnivorous Chinese longsnout catfish (Leiocassis longirostris Gunther). Triplicate tanks of fish were assigned to each of five isocaloric and isonitrogenous diets with different carbohydrate-to-lipid ratios (0.75, 1.48, 1.98, 2.99 and 5.07). The results showed that a higher specific growth rate (SGR) and feed rate (FR) were observed in the fish fed diet ratios of 1.98 CHO:L (P < 0.05). Overloading dietary carbohydrate (5.07 CHO:L ratio) caused skeletal malformations. Apparent digestibility of dry matter (ADC(d)) significantly increased with dietary CHO:L ratio (P < 0.05), while significantly higher apparent digestibility of protein (ADC(p)) and apparent digestibility of energy (ACD(e)) was observed only in the 1.98 CHO:L group (P < 0.05). Whole body contents of dry matter, lipid and energy significantly increased as the CHO:L ratio decreased (P < 0.05). The hepatosomatic index (HSI) was highest at 1.98 CHO:L ratio (P < 0.05). Highest dietary CHO:L ratio resulted in lower liver glycogen, liver lipid, plasma glucose and plasma triacylglycerol (P < 0.05), whereas there was no significant difference in plasma total cholesterol (P > 0.05). High dietary CHO:L ratio caused pathological changes in fish morphology and liver histology. Based on maximum growth, the optimal carbohydrate-to-lipid ratio was 1.98 for Chinese longsnout catfish.

Size-related shifts in reliance on benthic and pelagic food webs by lake anchovy

This paper reports large variations in stable carbon and nitrogen isotope ratios of lake anchovy (Coilia ectenes taihuensis) from Lake Chaohu, China. The lake anchovy exhibited a significant C-13- and N-15- enrichment in relation to increasing fish length, and the isotopic compositions of small lake anchovy (<= 130 mm) were significantly more enriched than those of large lake anchovy (> 130 mm). The significant differences in the isotopic compositions of small and large lake anchovy suggested that their assimilated diets differed over a period of time and reflected the size-related diet shift of this fish. Bellamya aeruginosa and Corbicula fluminea were used to establish the baseline carbon signal of benthic and pelagic food webs, and these data were used to parameterize a 2-source mixing model to estimate in consumers the contribution of carbon derived from benthic versus pelagic food webs. Mixing models showed that small lake anchovy derived only 37% of their carbon from benthic food web, indicating increased reliance on pelagic prey, whereas benthic prey contributed 71% of large lake anchovy diet, suggesting greater use of benthic sources. These data indicate that there was a change in lake anchovy feeding strategy related to their size, suggesting a role in dynamic coupling between pelagic and benthic food chains. The trophic position of small lake anchovy averaged 3.0, indicating a zooplankton-based diet, compared with 3.6 in large lake anchovy, indicative of an increase in piscivorous diet. Overlap in the isotopic compositions of small and large lake anchovy probably indicated that these fish occasionally shared common diets, as suggested by stomach content studies, and/or resulted from the differences in the rate of isotopic turnover depending on differences in growth rate and metabolic turnover between small and large anchovy during diet shift from pelagic to benthic food webs. This study presents the contributions of benthic and pelagic food webs supporting lake anchovy and indicates that the intraspecific isotopic dynamic should be considered when applying stable isotope analyses to infer trophic interactions in aquatic ecosystems.