Graze to grain - measuring and modelling the effects of grazed pasture leys on soil nitrogen and sorghum yield on a Vertosol soil in the Australian subtropics

Highly productive sown pasture systems can result in high growth rates of beef cattle and lead to increases in soil nitrogen and the production of subsequent crops. The nitrogen dynamics and growth of grain sorghum following grazed annual legume leys or a grass pasture were investigated in a no-till system in the South Burnett district of Queensland. Two years of the tropical legumes Macrotyloma daltonii and Vigna trilobata (both self regenerating annual legumes) and Lablab purpureus (a resown annual legume) resulted in soil nitrate N (0-0.9 m depth), at sorghum sowing, ranging from 35 to 86 kg/ha compared with 4 kg/ha after pure grass pastures. Average grain sorghum production in the 4 cropping seasons following the grazed legume leys ranged from 2651 to 4012 kg/ha. Following the grass pasture, grain sorghum production in the first and second year was < 1900 kg/ha and by the third year grain yield was comparable to the legume systems. Simulation studies utilising the farming systems model APSIM indicated that the soil N and water dynamics following 2-year ley phases could be closely represented over 4 years and the prediction of sorghum growth during this time was reasonable. In simulated unfertilised sorghum crops grown from 1954 to 2004, grain yield did not exceed 1500 kg/ha in 50% of seasons following a grass pasture, while following 2-year legume leys, grain exceeded 3000 kg/ha in 80% of seasons. It was concluded that mixed farming systems that utilise short term legume-based pastures for beef production in rotation with crop production enterprises can be highly productive.

Diel variation in mangrove fish abundances and trophic guilds of northeastern Australian estuaries with a proposed trophodynamic model

Diel activity patterns of tropical fish assemblages in turbid, mangrove-dominated estuaries remain largely undocumented, leading to uncertainty about ecological processes in these systems. To capture active fishes by day and night, gill nets were set perpendicular to mangrove shorelines, in six northeastern Australian estuaries during 13 bimonthly trips. Fish were sampled with eight large mesh (102-151 mm) nets, set for 6 hrs (1500-2100), and checked hourly (1146 day, 635 dusk, 872 night checks). Four smaller mesh (19-51 mm) nets were also set for 1 hr before and after sunset (77 day, 78 night checks). Of 157 total species, 22 were netted exclusively before sunset and 47 exclusively after sunset. All of the top 26 species were present both day and night, but of these, 46% were primarily nocturnal (diel index > 0.65). An average of 77.2 fish hr−1 were netted by day vs 171.4 by night. Within the 400 km coastal region, assemblages differed between two northern wave-dominated (WD) estuaries and four southern tide-dominated ('I'D) estuaries. In all six estuaries Lates calcarifer (Bloch, 1790) dominated night assemblages. In 'I'D estuaries, night assemblages were also dominated by Thryssa hamiltoni Gray, 1835 and Eleutheronema tetradactylum (Shaw, 1804); while in WD estuaries Herklotsichthys castelnaui (Ogilby, 1897), Leiognathus equulus (Forsskål, 1775), and Megalops cyprinoids (Broussonet, 1782) were dominant at night. Nocturnal species included planktivores and carnivores, while daytime assemblages were dominated by detritivores (Mugillidae). Higher night catch rates are attributed to increased activity by mobile fishes moving from mangrove to adjacent habitats to forage, especially immediately post-sunset. Although day-night diets and forage resources have yet to be compared in mangrove systems, previously unrecognized trophic relationships involving variation in diel activity among important fishery species (Centropomidae, polynemidae, Carangidae) and their prey may be key ecological processes in these tropical mangrove estuaries. A proposed hypothesis explaining diel variation in mangrove fish assemblages of tropical estuaries is presented through a conceptual model.

Language in Acquisition : Early Lexical Development and Associations between Lexicon and Grammar Findings from Full-Term and Very-Low-Birth-Weight Finnish Children

The aim was to analyse the growth and compositional development of the receptive and expressive lexicons between the ages 0,9 and 2;0 in the full-term (FT) and the very-low-birth-weight (VLBW) children who are acquiring Finnish. The associations between the expressive lexicon and grammar at 1;6 and 2;0 in the FT children were also studied. In addition, the language skills of the VLBW children at 2;0 were analysed, as well as the predictive value of early lexicon to the later language performance. Four groups took part in the studies: the longitudinal (N = 35) and cross-sectional (N = 146) samples of the FT children, and the longitudinal (N = 32) and cross-sectional (N = 66) samples of VLBW children. The data was gathered by applying of the structured parental rating method (the Finnish version of the Communicative Development Inventory), through analysis of the children´s spontaneous speech and by administering a a formal test (Reynell Developmental Language Scales). The FT children acquired their receptive lexicons earlier, at a faster rate and with larger individual variation than their expressive lexicons. The acquisition rate of the expressive lexicon increased from slow to faster in most children (91%). Highly parallel developmental paths for lexical semantic categories were detected in the receptive and expressive lexicons of the Finnish children when they were analysed in relation to the growth of the lexicon size, as described in the literature for children acquiring other languages. The emergence of grammar was closely associated with expressive lexical growth. The VLBW children acquired their receptive lexicons at a slower rate and had weaker language skills at 2;0 than the full-term children. The compositional development of both lexicons happened at a slower rate in the VLBW children when compared to the FT controls. However, when the compositional development was analysed in relation to the growth of lexicon size, this development occurred qualitatively in a nearly parallel manner in the VLBW children as in the FT children. Early receptive and expressive lexicon sizes were significantly associated with later language skills in both groups. The effect of the background variables (gender, length of the mother s basic education, birth weight) on the language development in the FT and the VLBW children differed. The results provide new information of early language acquisition by the Finnish FT and VLBW children. The results support the view that the early acquisition of the semantic lexical categories is related to lexicon growth. The current findings also propose that the early grammatical acquisition is closely related to the growth of expressive vocabulary size. The language development of the VLBW children should be followed in clinical work.

Aivojen jännitevasteiden rekisteröinti useaan äänen piirteeseen yhdellä mittauskerralla terveillä musiikkileikkikoulua käyvillä kaksivuotiailla

The early detection of hearing deficits is important to a child's development. However, examining small children with behavioural methods is often difficult. Research with ERPs (event-related potentials), recorded with EEG (electroencephalography), does not require attention or action from the child. Especially in children's ERP research, it is essential that the duration of a recording session is not too long. A new, faster optimum paradigm has been developed to record MMN (mismatch negativity), where ERPs to several sound features can be recorded in one recording session. This substantially shortens the time required for the experiment. So far, the new paradigm has been used in adult and school-aged children research. This study examines if MMN, LDN (late discriminative negativity) and P3a components can be recorded in two-year-olds with the new paradigm. The standard stimulus (p=0.50) was an 80 dB harmonic tone consisting of three harmonic frequencies (500 Hz, 1000 Hz and 1500 Hz) with a duration of 200 ms. The loudness deviants (p=0.067) were at a level of +6 dB or -6 dB compared to the standards. The frequency deviants (p=0.112) had a fundamental frequency of 550 or 454.4 Hz (small deviation), 625 or 400 Hz (medium deviation) or 750 or 333.3 Hz (large deviation). The duration deviants (p=0.112) had a duration of 175 ms (small deviation), 150 ms (medium deviation) or 100 ms (large deviation). The direction deviants (p=0.067) were presented from the left or right loudspeaker only. The gap deviant (p=0.067) included a 5-ms silent gap in the middle of the sound. Altogether 17 children participated in the experiment, of whom the data of 12 children was used in the analysis. ERP components were observed for all deviant types. The MMN was significant for duration and gap deviants. The LDN was significant for the large duration deviant and all other deviant types. No significant P3a was observed. These results indicate that the optimum paradigm can be used with two-year-olds. With this paradigm, data on several sound features can be recorded in a shorter time than with the previous paradigms used in ERP research.

Can feral pig harvesting and co-ordinated control reduce damage to grain crops?

Commercial and recreational harvesting of pigs is often encouraged by pest managers because it is essentially a ‘free’ reduction in pest density. However, the reduction in numbers may provide minimal damage mitigation and may be inappropriately allocated in space and time. Additionally, more effective control (e.g. baiting) may not occur because of the incorrect perception that harvesting is effective or because pigs are valued for recreational use.

Structure of a peptide oxazolone: 2-(1'-benzyloxycarbonylamino-1'-methylethyl)-4,4-dimethyl-5-oxazolone

C16H20N204, monoclinic, P21, a = 6.270 (1),b= 11.119(3),c= ll.640(4)A, fl= 100.7 (2)°,Dm = 1-27 (flotation), Dc = 1-26 Mg m -3, Z = 2. The structure has been refined to a final R value of 0.041 for 1584 independent counter-measured reflections. The oxazolone ring in the molecule is nearly planar. The exocyclic O atom is 0.065 A out of the plane defined by the other four atoms in the ring belonging to the lactone group. The difference in length between the two adjacent C-O bonds in the ring is small, but significant. The crystal structure is stabilized by van der Waals interactions and a N--H... N hydrogen bond.

Selecting replacements for invasive plants to support frugivores in highly modified sites: a case study focusing on Lantana camara

Invasive plants are regarded as a major threat to biodiversity worldwide. Yet, in some cases, invasive plants now perform important ecological functions. For example, fleshy-fruited invasive plants provide food that supports indigenous frugivore populations. How can the disparate goals of conservation versus invasive weed control be managed? We suggest using the fruit characteristics of the invasive plant to select replacement indigenous plants that are functionally similar from the perspective of frugivores. These could provide replacement food resources at sites where plants with these characteristics are part of the goal plant community and where such plants would not otherwise regenerate. Replacement plants could also redirect seed dispersal processes to favour indigenous, rather than invasive, plant species. We investigated the utility of this approach by ranking all indigenous fleshy-fruited plant species from a region using a simple model that scored species based upon measures of fruit phenology, morphology, conspicuousness and accessibility relative to a target invasive species, Lantana (Lantana camara). The model successfully produced high scores for indigenous plant species that were used by more of the frugivores of Lantana than a random selection of plants, suggesting that this approach warrants further investigation.

Polychaete-assisted sand filters

The objective of this study was to investigate the productivity and functionality of sand filters stocked with marine worms for wastewater treatment at mariculture facilities. Medium bedding sand which is commonly available in coastal sedimentary deposits and nereidid polychaetes (Perinereis nuntia and P. helleri) from Moreton Bay in southeast Queensland were combined and studied in down-flow sand filtration beds. This combination appears to provide a new option for brackish wastewater treatment whereby the activities of the worms help to prevent sand filters from blocking with organic debris and their biomass offers a valuable by-product. Phytoplankton-rich pond waters percolating through sand-worm beds were reliably treated in several useful ways: suspended solids and chlorophyll a levels were consistently reduced by >50% by the process, and nutrients were converted into bio-available dissolved forms. Dissolved oxygen, redox and pH levels were also lowered significantly by the process. Water treatment rates of approx 1500 L m-2 d-1 were routinely achieved. P. nuntia appeared more suitable than P. helleri for stocking directly into sand filtration beds as nectochaetes, but generally exhibited slower growth. Survival and growth were influenced by stocking density. Sand-filter beds stocked with juvenile worms and fed only with eutrophic pond water demonstrated polychaete production capacities in the order of 300-400 g m-2 (eg. P. helleri: 328 g m-2 in 16 weeks). These results show how nereidid polychaetes can be reliably produced within simple, low-maintenance sand filters, and provide data necessary for the functional integration of this novel wastewater treatment system into contemporary seafood farming systems.

Evaluating the efficacy of the EZ-Ject herbicide system in Queensland, Australia

The EZ-Ject herbicide system was evaluated as a stem injection method for controlling woody weeds in a range of situations where traditional chemical application methods have limited scope. The equipment was trialled on three Queensland weed species; pond apple (Annona glabra), velvety tree pear (Opuntia tomentosa) and yellow oleander (Cascabela thevetia); at five different cartridge densities (0, 1, 2, 3 and 4) and with two herbicides (glyphosate and imazapyr). Cartridges filled with imazapyr were significantly more effective at controlling the three woody weed species than those filled with glyphosate. Injecting plants with three imazapyr cartridges resulted in plant kills ranging from 93 to 100%, compared with glyphosate kills of 17 to 100%. Pond apple was the most susceptible species, requiring one imazapyr cartridge or two glyphosate cartridges to kill 97 and 92% of the treated plants. Plant mortality increased as the number of cartridges injected increased. Mortality did not differ significantly for treatments receiving three and four imazapyr cartridges, as these cartridge densities met the criterion of injecting one cartridge per 10-cm basal circumference, a criterion recommended by the manufacturers for treating large plants (>6.35 cm in diameter at breast height). The cost of treating a weed infestation of 1500 plants ha–1 with three cartridges per tree is $1070 ha–1, with labour costs accounting for 16% of the total. The high chemical costs would preclude this technique from broad-scale use, but the method could have application for treating woody weeds in sensitive, high conservation areas.

Nutrient loss and water quality under extensive grazing in the upper Burdekin river catchment, North Queensland

Increased sediment and nutrient losses resulting from unsustainable grazing management in the Burdekin River catchment are major threats to water quality in the Great Barrier Reef Lagoon. To test the effects of grazing management on soil and nutrient loss, five 1 ha mini-catchments were established in 1999 under different grazing strategies on a sedimentary landscape near Charters Towers. Reference samples were also collected from watercourses in the Burdekin catchment during major flow events.Soil and nutrient loss were relatively low across all grazing strategies due to a combination of good cover, low slope and low rainfall intensities. Total soil loss varied from 3 to 20 kg haˉ¹ per event while losses of N and P ranged from 10 to 1900 g haˉ¹ and from 1 to 71 g haˉ¹ per event respectively. Water quality of runoff was considered moderate across all strategies with relatively low levels of total suspended sediment (range: 8-1409 mg lˉ¹), total N (range: 101-4000 ug lˉ¹) and total P (range: 14-609 ug lˉ¹). However, treatment differences are likely to emerge with time as the impacts of the different grazing strategies on land condition become more apparent.Samples collected opportunistically from rivers and creeks during flow events displayed significantly higher levels of total suspended sediment (range: 10-6010 mg lˉ¹), total N (range: 650-6350 ug lˉ¹) and total P (range: 50-1500 ug lˉ¹) than those collected at the grazing trial. These differences can largely be attributed to variation in slope, geology and cover between the grazing trial and different catchments. In particular, watercourses draining hillier, grano-diorite landscapes with low cover had markedly higher sediment and nutrient loads compared to those draining flatter, sedimentary landscapes.These preliminary data suggest that on relatively flat, sedimentary landscapes, extensive cattle grazing is compatible with achieving water quality targets, provided high levels of ground cover are maintained. In contrast, sediment and nutrient loss under grazing on more erodable land types is cause for serious concern. Long-term empirical research and monitoring will be essential to quantify the impacts of changed land management on water quality in the spatially and temporally variable Burdekin River catchment.

Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to clarify the intra-specific variation in the performance of A. senegal and, specifically, the adaptation of trees of different origin to the clay soils of the Blue Nile region. In agroforestry systems established at the beginning of the study, tree and crop growth, water use, gum and crop yields, nutrient cycling and system performance were investigated for a period of four years (1999 to 2002). Trees were grown at 5 x 5 m and 10 x 10 m spacing alone or in mixture with sorghum or sesame; crops were also grown in sole culture. The symbiotic biological N2 fixation by A. senegal was estimated using the 15N natural abundance (δ15N) procedure in eight provenances collected from different environments and soil types of the gum arabic belt and grown in clay soil in the Blue Nile region. Balanites aegyptiaca (a non-legume) was used as a non-N-fixing reference tree species, so as to allow 15N-based estimates of the proportion of the nitrogen in trees derived from the atmosphere. In the planted acacia trees, measurements were made on shoot growth, water-use efficiency (as assessed by the δ13C method) and (starting from the third year) gum production. Carbon isotope ratios were obtained from the leaves and branch wood samples. The agroforestry system design caused no statistically significant variation in water use, but the variation was highly significant between years, and the highest water use occurred in the years with high rainfall. No statistically significant differences were found in sorghum or sesame yields when intercropping and sole crop systems were compared (yield averages were 1.54 and 1.54 ha-1 for sorghum and 0.36 and 0.42 t ha-1 for sesame in the intercropped and mono-crop plots, respectively). Thus, at an early stage of agroforestry system management, A. senegal had no detrimental effect on crop yield, but the pattern of resource capture by trees and crops may change as the system matures. Intercropping resulted in taller trees and larger basal and crown diameters as compared to the development of sole trees. It also resulted in a higher land equivalent ratio. When gum yields were analysed it was found that a significant positive relationship existed between the second gum picking and the total gum yield. The second gum picking seems to be a decisive factor in gum production and could be used as an indicator for the total gum yield in a particular year. In trees, the concentrations of N and P were higher in leaves and roots, whereas the levels of K were higher in stems, branches and roots. Soil organic matter, N, P and K contents were highest in the upper soil stratum. There was some indication that the P content slightly increased in the topsoil as the agroforestry plantations aged. At a stocking of 400 trees ha-1 (5 x 5 m spacing), A. senegal accumulated in the biomass a total of 18, 1.21, 7.8 and 972 kg ha-1of N, P, K and OC, respectively. Trees contributed ca. 217 and 1500 kg ha-1 of K and OC, respectively, to the top 25-cm of soil over the first four years of intercropping. Acacia provenances of clay plain origin showed considerable variation in seed weight. They also had the lowest average seed weight as compared to the sandy soil (western) provenances. At the experimental site in the clay soil region, the clay provenances were distinctly superior to the sand provenances in all traits studied but especially in basal diameter and crown width, thus reflecting their adaptation to the environment. Values of δ13C, indicating water use efficiency, were higher in the sand soil group as compared to the clay one, both in leaves and in branch wood. This suggests that the sand provenances (with an average value of -28.07 ) displayed conservative water use and high drought tolerance. Of the clay provenances, the local one (Bout) displayed a highly negative (-29.31 ) value, which indicates less conservative water use that resulted in high productivity at this particular clay-soil site. Water use thus appeared to correspond to the environmental conditions prevailing at the original locations for these provenances. Results suggest that A. senegal provenances from the clay part of the gum belt are adapted for a faster growth rate and higher biomass and gum productivity as compared to provenances from sand regions. A strong negative relationship was found between the per-tree gum yield and water use efficiency, as indicated by δ13C. The differences in water use and gum production were greater among provenance groups than within them, suggesting that selection among rather than within provenances would result in distinct genetic gain in gum yield. The relative δ15N values ( ) were higher in B. aegyptiaca than in the N2-fixing acacia provenances. The amount of Ndfa increased significantly with age in all provenances, indicating that A. senegal is a potentially efficient nitrogen fixer and has an important role in t agroforestry development. The total above-ground contribution of fixed N to foliage growth in 4-year-old A. senegal trees was highest in the Rahad sand-soil provenance (46.7 kg N ha-1) and lowest in the Mazmoom clay-soil provenance (28.7 kg N ha-1). This study represents the first use of the δ15N method for estimating the N input by A. senegal in the gum belt of Sudan. Key words: Acacia senegal, agroforestry, clay plain, δ13C, δ15N, gum arabic, nutrient cycling, Ndfa, Sorghum bicolor, Sesamum indicum

The conservation status of the world’s reptiles

Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of human-induced habitat loss and harvesting, which are the predominant threats to reptiles.

Exercise and vascular function in child obesity: A meta-analysis

CONTEXT: Conduit artery flow-mediated dilation (FMD) is a noninvasive index of preclinical atherosclerosis in humans. Exercise interventions can improve FMD in both healthy and clinical populations. OBJECTIVE: This systematic review and meta-analysis aimed to summarize the effect of exercise training on FMD in overweight and obese children and adolescents as well as investigate the role of cardiorespiratory fitness (peak oxygen consumption [Vo2peak]) on effects observed. DATA SOURCES: PubMed, Medline, Embase, and Cinahl databases were searched from the earliest available date to February 2015. STUDY SELECTION: Studies of children and/or adolescents who were overweight or obese were included. DATA EXTRACTION: Standardized data extraction forms were used for patient and intervention characteristics, control/comparator groups, and key outcomes. Procedural quality of the studies was assessed using a modified version of the Physiotherapy Evidence Base Database scale. RESULTS: A meta-analysis involving 219 participants compared the mean difference of pre- versus postintervention vascular function (FMD) and Vo2peak between an exercise training intervention and a control condition. There was a significantly greater improvement in FMD (mean difference 1.54%, P < .05) and Vo2peak (mean difference 3.64 mL/kg/min, P < .05) after exercise training compared with controls. LIMITATIONS: Given the diversity of exercise prescriptions, participant characteristics, and FMD measurement protocols, varying FMD effect size was noted between trials. CONCLUSIONS: Exercise training improves vascular function in overweight and obese children, as indicated by enhanced FMD. Further research is required to establish the optimum exercise program for maintenance of healthy vascular function in this at-risk pediatric population.

Phase transition in malonic acid: An infrared study

Malonic acid is shown to undergo an interesting phase transition at 360 K when the two non-equivalent cyclic hydrogen-bonded dimers present in the low-temperature phase become equivalent.

Susceptibility to sulfuryl fluoride and lack of cross-resistance to phosphine in developmental stages of the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

BACKGROUND Our aim was to ascertain the potential of sulfuryl fluoride (SF) as an alternative fumigant to manage phosphine-resistant pests. We tested the susceptibility of all life stages of red flour beetle, Tribolium castaneum (Herbst), to SF and assessed the presence of cross-resistance to this fumigant in phosphine-resistant strains of this species. RESULTS Analysis of dose–response data indicated that the egg was the stage most tolerant to SF under a 48 h exposure period. At LC50, eggs were 29 times more tolerant than other immature stages and adults, and required a relatively high concentration of 48.2 mg L−1 for complete mortality. No significant differences in tolerance to SF were observed among the three larval instars, pupae and adults, and all of these stages were controlled at a low concentration of 1.32 mg L−1. Phosphine-resistant strains did not show cross-resistance to SF. CONCLUSION Our research concluded that the current maximum registered rate of SF, 1500 gh m−3, is adequate to control all the post-embryonic life stages of T. castaneum over a 48 h fumigation period, but it will fail to achieve complete mortality of eggs, indicating the risk of some survival of eggs under this short exposure period. As there is no cross-resistance to SF in phosphine-resistant insects, it will play a key role in managing phosphine resistance in stored-grain insect pests. © 2014 Commonwealth of Australia. Pest Management Science © 2014 Society of Chemical Industry