Genetics of autistic disorders : review and clinical implications

Twin and family studies in autistic disorders (AD) have elucidated a high heritability of AD. In this literature review, we will present an overview on molecular genetic studies in AD and highlight the most recent findings of an increased rate of copy number variations in AD. An extensive literature search in the PubMed database was performed to obtain English published articles on genetic findings in autism. Results of linkage, (genome wide) association and cytogenetic studies are presented, and putative aetiopathological pathways are discussed. Implications of the different genetic findings for genetic counselling and genetic testing at present will be described. The article ends with a prospectus on future directions. Keywords: Autistic disorder , Linkage , Whole genome association , Copy number variation , Mutatio

Will Small-Scale Dairy Producers in Kenya Disappear Due to Economies of Scale in Production?

There is growing policy concern regarding the competitiveness of small-scale livestock production in the wake of the contemporary livestock revolution in many developing countries. In Kenya, this debate has focused on economies of scale and the undue influence of policy distortions on promoting the scaling up of dairy farms. This paper seeks to investigate economies of scale in Kenyan dairy in terms of relative profit efficiency at different levels of output, and identify policy and technology options to help small-scale farmers develop solutions to the challenges of competition. Data were collected from 204 dairy producers of different farm sizes in rural Kiambu and Thika, and urban Nairobi districts and a stochastic frontier model approach was used to analyze the determinants of profitability and inefficiency. Unit profitability per farm ranged between US$0.13 - US$0.16 per liter of milk with no significant variation across scales of farm. However, at all given levels of scale of farm, inefficiency significantly contributed to variability in profitability across farms. Scale had no significant effect on efficiency, confirming the relative competitiveness of small-scale dairy producers. Dairy farmers with commercial poultry achieved higher relative profit efficiency as poultry waste was fed to cattle. Rural location relative to Nairobi also increased efficiency. Linking rural areas and major market centre with good roads, strengthening of farmers' co-operative societies and exploring use of cheaper raw materials in the manufacture of concentrate feeds may strengthen the competitive position small dairy farms versus large ones.Dairy Production, Stochastic Production Frontier, Efficiency, Profitability, Livestock Production/Industries, C21, Q12,

SPATIAL ANALYSIS OF SOIL FERTILITY MANAGEMENT USING INTEGRATED HOUSEHOLD AND GIS DATA FROM SMALLHOLDER KENYAN FARMS

Although soil fertility is recognized as a primary constraint to agricultural production in developing countries, use of fertilizer in Sub-Saharan Africa is declining. Smallholder farmers still rely heavily on livestock manure for soil fertility management. To explore the determinants of soil fertility management practices, including both the use of cattle manure and inorganic fertilizer, data are used from a sample of 3,330 geo-referenced farm households across Central and Western Kenya. A bivariate probit model is applied to jointly examine the use of the two technologies. Particular attention is given to measures of location related to market access and agroclimate, which in the adoption literature have typically been addressed using crude proxies. To avoid such proxies, GIS-derived variables are integrated into the household decision model. Their use also allows the spatial prediction of uptake based on parameter estimates. The results show clearly the derived-demand nature of soil fertility services, based on markets for farm outputs. They also illustrate that supply of manure for soil fertility amendments is conditioned by demand for livestock products, especially milk. The integration of GIS-derived variables is shown to better estimate the effects of location than the usual measures employed, and offers scope to wider use in technology adoption research.spatial analysis, soil fertility, market access, technology adoption., Farm Management, Land Economics/Use, Q12, Q16,

The Ocean – Continent Transition Zones Along the Appalachian – Caledonian Margin of Laurentia: Examples of Large-Scale Hyperextension During the Opening of the Iapetus Ocean

A combination of deep seismic imaging and drilling has demonstrated that the ocean-continent transition (OCT) of present-day, magma-poor, rifted continental margins is a zone of hyperextension characterized by extreme thinning of the continental crust that exhumed the lowermost crust and/or serpentinized continental mantle onto the seafloor. The OCT on present-day margins is difficult to sample, and so much of our knowledge on the detailed nature of OCT sequences comes from obducted, magma-poor OCT ophiolites such as those preserved in the upper portions of the Alpine fold-and-thrust belt. Allochthonous, lens-shaped bodies of ultramafic rock are common in many other ancient orogenic belts, such as the Caledonian – Appalachian orogen, yet their origin and tectonic significance remains uncertain. We summarize the occurrences of potential ancient OCTs within this orogen, commencing with Laurentian margin sequences where an OCT has previously been inferred (the Dalradian Supergroup of Scotland and Ireland and the Birchy Complex of Newfoundland). We then speculate on the origin of isolated occurrences of Alpine-type peridotite within Laurentian margin sequences in Quebec – Vermont and Virginia – North Carolina, focusing on rift-related units of Late Neoproterozoic age (so as to eliminate a Taconic ophiolite origin). A combination of poor exposure and pervasive Taconic deformation means that origin and emplacement of many ultramafic bodies in the Appalachians will remain uncertain. Nevertheless, the common occurrence of OCT-like rocks along the whole length of the Appalachian – Caledonian margin of Laurentia suggests that the opening of the Iapetus Ocean may have been accompanied by hyperextension and the formation of magma-poor margins along many segments.SOMMAIREDes travaux d’imagerie sismique et des forages profonds ont montré que la transition océan-continent (OCT) de marges continentales de divergence pauvre en magma exposée de nos jours, correspond à une zone d’hyper-étirement tectonique caractérisée par un amincissement extrême de la croûte continentale, qui a exhumé sur le fond marin, jusqu’à la tranche la plus profonde de la croûte continentale, voire du manteau continental serpentinisé.  Parce qu’on peut difficilement échantillonner l’OCT sur les marges actuelles, une grande partie de notre compréhension des détails de la nature de l’OCT provient d’ophiolites pauvres en magma d’une OCT obduite, comme celles préservées dans les portions supérieures de la bande plissée alpine.  Des masses lenticulaires de roches ultramafiques allochtones sont communes dans de nombreuses autres bandes orogéniques anciennes, comme l’orogène Calédonienne-Appalaches, mais leur origine et signification tectonique reste incertaine.  Nous présentons un sommaire des occurrences d’OCT potentielles anciennes de cet orogène, en commençant par des séquences de la marge laurentienne, où la présence d’OCT a déjà été déduites (le Supergroupe Dalradien d’Écosse et d'Irlande, et le complexe de Birchy de Terre-Neuve).  Nous spéculons ensuite sur l'origine de cas isolés de péridotite de type alpin dans des séquences de marge des Laurentides du Québec-Vermont et de la Virginie-Caroline du Nord, en nous concentrant sur les unités de rift d'âge néoprotérozoïque tardif (pour éviter les ophiolites du Taconique).  La conjonction d’affleurements de piètre qualité et de la déformation taconique omniprésente, signifie que l'origine et la mise en place de nombreuses masses ultramafiques dans les Appalaches demeureront incertaines.  Néanmoins, la présence fréquente de roches de type OCT tout le long de la marge Calédonnienne-Appalaches de Laurentia suggère que l'ouverture de l'océan Iapetus peut avoir été accompagnée d’hyper-étirement et de la formation de marges pauvres en magma le long de nombreux segments

Constraints to the sustainability of a ‘systematised’ approach to livestock marketing amongst smallholder cattle producers in South Africa

Commercialization of smallholder agriculture in South Africa is underpinned by reforms to improve livestock off-take in communal areas and engage smallholder farmers with formal markets. To achieve this, Custom Feeding Programmes (CFPs) were established to improve the condition of communal cattle prior to their sale into formal markets and to ‘systematise’ the informal marketing of cattle in communal areas by enabling participants to achieve higher informal market prices. We evaluate the sustainability of eight CFPs located in Eastern Cape Province in terms of their ability to add value to smallholder cattle production and encourage market participation. Communities with CFPs achieved a 16.6% mean cattle off-take rate, substantially higher than in most communal systems. Furthermore, cattle sold through CFPs attained a 17% higher mean selling price than those sold through other marketing channels. However, these benefits were mainly realized by better-off farmers with larger cattle herds and greater ability to transport animals to and from CFPs. More marginalized farmers, particularly women, had low participation. CFPs also face challenges to their sustainability, including inconsistent feed and water supplies, poor infrastructure and high staff turnover. Key to enhancing participation in CFPs, will be improving the way they are supported and embedded within communities

The role of market outlet in determining terms for milk sales by smallholders in Kenya

Dairy production is a key small farm strategy for generating income in the Nairobi milk shed. The high perishability of milk under Kenyan conditions appears to be associated with a high frequency of small individual transactions, the terms of which are subject to forced “fire” sales, delayed payments or default. Reliability of outlets in the wet (milk glut) season is also a consideration, and credit sales typically are matched with a commitment to be a steady customer. Two salient phenomena are observed: reported unit milk prices differ widely within the same location and time period, and spot sales for cash tend to be at a higher unit price than sales on monthly credit. We hypothesize that dairy farmers in the Nairobi milk shed choose market outlets and levels of cash sales that reduce transactions costs and help assure reliable future outlets, at the expense of current income. A decomposition of producer milk prices across time, space, and market outlet suggests that reliability of outlet is worth up to 17 % of the spot price, in addition to waiting a month to be paid. Risks of credit default are illustrated by predicted weekly credit prices that are 5 % lower than monthly credit prices. Data from 21 smallholder farms monitored daily over one year are used to estimate a two-limit Tobit model of the role of the characteristics of market outlets and producers in explaining the share of producer output sold for cash rather than credit. Younger, more educated producers, receiving a regular off-farm salary, and near market centres are shown to be more likely to accept sales on credit. Older producers with more experience but less formal education are more likely to sell for cash rather than credit. The power of the model to explain different prices for milk in the same location and week suggests that such price differences viewed unidimensionally are not evidence of lack of market integration as conventionally defined, but an outcome of differential transactions costs and perceptions of risk by different producers

Hydraulic performance of elastomeric bonded permeable revetments and subsoil response to wave loads

Elastomeric bonded permeable revetments, also called PBA (Polyurethane bonded aggregate) revetments, are highly porous structures made of mineral aggregates (e.g. crushed stones) which are durably and elastically bonded by polyurethane (PU). Despite their numerous advantages as compared to conventional revetments and the large experience available from more than 25 pilot projects, physically-based design formulae to predict their hydraulic performance, wave loading and response are still lacking. Therefore, the present study aims at improving the understanding of the processes involved in the interaction between wave, revetment and foundation, based on large-scale model tests performed in the Coastal Research Centre (FZK), Hannover/Germany, and to provide prediction formulae/diagrams. This paper is focused on the prediction of the hydraulic performance (wave reflection, wave runup and run-down) and the response of the sand core (pore pressure) beneath the revetment for a wide range of wave conditions, including the analysis of an observed failure due to transient soil liquefaction.BASF-Elastogran Gmb

Olfactomedin 4 Serves as a Marker for Disease Severity in Pediatric Respiratory Syncytial Virus (RSV) Infection

Funding: Statement of financial support: The study was financially supported by the VIRGO consortium, an Innovative Cluster approved by the Netherlands Genomics Initiative and partially funded by the Dutch Government (BSIK 03012). The authors have indicated they have no personal financial relationships relevant to this article to disclose. Data Availability Statement: The data is accessible at http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE69606.Peer reviewedPublisher PD