Effects of grain size distribution on the initial strain shear modulus of calcareous sand

The soil’s small strain shear modulus, Gmax or G0, is applied in dynamic behavior analyses and is correlated to other soil properties (density and void ratio) for predicting soil dynamic behavior under seismic loadings such as earthquakes, machinery or traffic vibrations. However, for calcareous sands, selecting representative samples for the field conditions is difficult; therefore, almost all measured soil parameters (post-seismic properties) do not reflect exactly the soil state before seismic loading. In some cases of dynamic loading, a change in grain size distribution (GSD) of soils, especially for calcareous sands might occur. Moreover, many of these sand types behave differently from silica sands owing to their mineralogy, particle characterization, soil skeleton, and the continuous changing of particle size. For this reason, a series of isotropic consolidation tests in ranges of confining pressure from 25 to 300 kPa as well as bender element measurements on a calcareous sand and on a reference silica sand were performed in this study. The effects of differences in gradation and in the type of material on the soil’s small strain shear modulus, Gmax, are discussed

The economics of land fragmentation in the north of Vietnam

Land fragmentation, where a single farm has a number of parcels of land, is a common feature of agriculture in many countries, especially in developing countries. In Vietnam, land fragmentation is common, especially in the north. For the whole country, there are about 75 million parcels of land, an average of seven to eight plots per farm household. Such fragmentation can be seen to have negative and positive benefits for farm households and the community generally. Comparative statics analysis and analysis of survey data have led to the conclusion that small-sized farms are likely to be more fragmented, and that fragmentation had a negative impact on crop productivity and increased family labour use and other money expenses. Policies which allow the appropriate opportunity cost of labour to be reflected at the farm level may provide appropriate incentives to trigger farm size change and land consolidation. Policies which tip the benefits in favour of fewer and larger plots, such as strong and effective research and development, an active extension system and strong administrative management, may also lead to land consolidation.development economics, land fragmentation, land use and tenure, production economics, Resource /Energy Economics and Policy,

The economics of land fragmentation in the north of Vietnam

Land fragmentation, in which a single farm household operates more than one separate piece of land, is significant issue in Vietnamese agriculture, especially in the North. For the whole country, there are about 75 million plots of land, an average of 7-8 plots per farm household. Such fragmentation can be seen to have negative and positive benefits for farm households and the community generally. The negative impacts can be reduced mechanisation, higher cost, loss of land due to boundaries, increased negative externalities, and more limited application of new technologies. On the other hand, land fragmentation may have some benefits to farmers such as spreading output risk, seasonal labour use, and crop diversification. Comparative static analysis and analysis of survey data have led to the conclusion that small sized farms are likely to be more fragmented and the number of plots held by a household is not a significant determinant of yield and output risk spreading but is a significant factor in crop diversification. Policies which allow the appropriate opportunity cost of labour to be reflected at the farm level may provide appropriate incentives to trigger farm size change and land consolidation. Policies which tip the benefits in favour of fewer and larger plots such as strong and effective research and development, an active extension system and strong administrative management may also lead to land consolidation and thus allow some of the benefits which will accrue to the economy more generally to be obtained by farmers.Land Economics/Use,

Standardisation of Environmental Enrichment for Laboratory Mice and Rats: Utilisation, Practicality and Variation in Experimental Results

Rats and mice are the most commonly used species as laboratory animal models of diseases in biomedical  research. Environmental factors such as cage size, number of cage mates and cage structure such as environmental  enrichment can affect the physiology and behavioural development of laboratory animals and  their well-being throughout their lives. Therefore compromising the animals’ well-being due to inadequate  environmental conditions would diminish the value of the research models. In order to improve laboratory  animals’ well-being and promote the quality of animal based biomedical research, it is fundamentally  important that the environment of the animals meets the animals’ species typical behavioural needs. Standardisation  of environmental enrichment for laboratory rats and mice therefore should provide possibilities  for the animals to engage in at least the essential behavioural needs such as social contact, nest building,  exploring and foraging. There is a wide variety of environmental enrichment items commercially available  for laboratory mice and rats. However, how these items are used by the animals, their practicality in the  laboratory and whether these enrichments might lead to increased variation in experimental results have  not been widely assessed. In this study, we implemented two standardised enrichment items (shelters, nesting  materials) for rats and mice at different animal units. We instructed the animal care staff in monitoring  the use of enrichment items by the animals by means of a daily score sheet system. The animal staff ’s  viewpoint on practicality of the standardised enrichment program was assessed with a monthly score sheet  survey. Also we assessed whether the enriched environment affected breeding results and contributed to an  increase in variation of experimental data from several participating current studies. Our results show that  the animals readily used the provided enrichment items. A slight increase in workload for the animal staff  was reported. However, the overall judgement was mainly reported as good. Breeding results and variation  in experimental data did not reveal differences as compared to data from previous housing and/or non enriched  housing conditions. Overall, the results indicate that standard environmental enrichment that is species  appropriate may enhance the animal’s well-being without undesirable side effects on the experimental  outcome and daily working routine of the animal care staff.

Low dietary intakes of essential nutrients during pregnancy in Vietnam

Inadequate intake of nutrients during pregnancy has been associated with poor pregnancy and infant outcomes; however, evidence remains limited in low-resource settings in Asia. This paper assessed food, macronutrient, and micronutrient intakes among 1944 Vietnamese pregnant women. Dietary information was collected via an interviewer-administered food frequency questionnaire, and nutrient intakes were estimated using the Vietnamese food composition tables. The levels of nutrient intakes were evaluated against the Vietnamese recommended nutrient intakes (RNI) for pregnancy. The diet profiles were reported as means and percentages. The average daily food intakes across socio-demographic factors were compared using ANOVA, with adjustment for multiple comparisons by the Tukey–Kramer test. Rice, fruits, and vegetables were the main food sources consumed. The mean energy intake was 2004 kcal/day with 15.9%, 31.8%, and 52.2% of energy deriving from proteins, fats, and carbohydrates, respectively. Just over half of the women did not meet the RNI for total energy intake. The intakes of essential micronutrients including folate, calcium, iron, and zinc were below the RNI, and almost all pregnant women failed to meet the recommendations for these micronutrients. The associations of maternal age, education, and pre-pregnancy body mass index with nutrient intakes varied across the nutrient subgroups. Targeted programs are needed to improve nutrient intakes in Vietnamese pregnant women

Inventarisatie, voorkoming en bestrijding van fytoplasma en zijn vector in Muscari. Voortgezet diagnostisch onderzoek 2010/2011

Bij de broei van Muscari op pot kwamen vanaf 2007 veel klachten voor van ongelijke beworteling en ongelijke gewasontwikkeling uit ogenschijnlijk volkomen gezonde Muscaribollen. Aanvankelijk werd gedacht aan schade door herbiciden of het moment van rooien van de Muscaribollen voorafgaande aan het broeiseizoen. Uit (voortgezet) diagnostisch onderzoek bleek dat daarvan geen sprake was. In 2010 bleek uit diagnostisch onderzoek dat in Muscaribollen met achterblijvende beworteling en groei in de broeierij regelmatig fytoplasma kon worden aangetoond. In 2010 is ook fytoplasma in Scilla mischtschenkoana aangetoond met vergelijkbare symptomen als bij Muscari en hyacinten. Daarmee werd duidelijk dat bij Muscari, en incidenteel ook Scilla, sprake kan zijn van zogenaamde “Lissers” zoals we dit ook kennen bij hyacinten.Om meer inzicht te krijgen in deze voor Muscari nieuwe ziekte en om na te gaan of fytoplasma’s in Muscaribollen zijn te bestrijden is voortgezet diagnostisch onderzoek uitgevoerd. Daarbij zijn via verschillende kanalen extra monsters Muscari’s uit de broeierij verzameld en middels PCR-technieken getoetst op fytoplasma’s. Het bleek dat in veel partijen Muscaribollen die op zogenaamde “luwe tuinen” waren geteeld in de broeierij regelmatig sprake was van achterblijvende planten waarin fytoplasma kon worden aangetoond. Het betrof steeds het fytoplasma dat tot de Aster Yellows Group (16Sr-I) behoorde. Dit is dezelfde groep fytoplasma die bij hyacint “Lissers” kan veroorzaken. Het werd duidelijk dat het probleem van een fytoplasma-besmetting in partijen Muscaribollen groter was dan men aanvankelijk dacht. Dit maakt het dan ook noodzakelijk dat tijdens de bollenteelt van Muscari extra aandacht wordt geschonken aan de bestrijding van dwergcicaden, de vector van fytoplasma. Daarom is in 2010 een vakbladartikel gepubliceerd in BloembollenVisie om de bollentelers van Muscaribollen te informeren over de nieuwe ziekte waardoor ze in het lopende groeiseizoen nog in staat waren om maatregelen te nemen tegen (dwerg)cicaden.In 2010 en 2011zijn ook slecht bewortelde Muscaribollen uit de broeierij verzameld om na te gaan of met behulp van een warmwaterbehandeling fytoplasma is te doden. Ook is nagegaan of een boldompeling vóór het planten in imidacloprid (Admire) effectief beschermend kan werken tegen dwergcicaden waardoor de overdracht en verspreiding van fytoplasma’s in Muscari tijdens de bollenteelt kan worden voorkomen. Het bleek dat een warmwaterbehandeling van 2 uur bij 43,5ºC geen meetbare dodingseffect had op fytoplasma. Van deze cultuurkook mag in de praktijk dus niets worden verwacht ten aanzien van de doding van fytoplasma in Muscaribollen. Ook een warmwaterbehandeling van 4 uur 45ºC gaf geen volledige doding van fytoplasma in Muscari. Of imidacloprid (Admire) een effect heeft gehad op het besmet raken van Muscaribollen door fytoplasma is onduidelijk gebleven. Tijdens de veldproef was het niet mogelijk voldoende ziektedruk aan te leggen voor overdrachtsexperimenten De conclusie is dan ook dat een warmwaterbehandeling van leverbare Muscaribollen geen voldoende oplossing biedt om een besmetting met fytoplasma te bestrijden. Vooralsnog is dus de beste methode om een besmetting met fytoplasma te voorkomen door middel van perceelkeuze het gewas tijdens de bollenteelt vrij te houden van dwergcicaden zodat deze de fytoplasma niet kunnen overdragen op het Muscarigewas

Helminth eggs die-off and nutrients : human excreta storage experiment

Are the current practices of handling human excreta for agricultural purposes by farmers in Vietnam good enough?This study set up an excreta storage experiment to research how to inactivate Ascaris lumbricoides eggs and stillmaintain the nutrient value of human excreta

Synthesis of new simplified hemiasterlin derivatives with α,β-unsaturated carbonyl moiety.

International audienceIn this Letter, we report a convenient and efficient method for the synthesis of new simplified derivatives of hemiasterlin in which the α,α-dimethylbenzylic moiety A is replaced by α,β-unsaturated aryl groups as Michael acceptor. Most of these derivatives have a strong cytotoxic activity on three human tumor cell lines (KB, Hep-G2 and MCF7). Analogs 17b and 17f showed a high cytotoxicity against KB and Hep-G2 cancer cell lines comparable to paclitaxel and ellipticine