"Economic Aid to Post-conflict Countries: A Methodological Critique of Collier and Hoeffler"

This paper retests the analysis of "Aid Policy and Growth in Post-Conflict Societies," by Paul Collier and Anke Hoeffler (October 2002 and forthcoming in European Economic Review). It finds that their data and analysis do not support their conclusions and policy recommendations on the optimal timing and amounts of aid. These conclusions depend on very few observations (13 for the period of peace-onset, 13 for years 4 to 7 when a growth spurt is said to make aid particularly effective, and 8 for the period when aid should taper off); are vulnerable to the same methodological misspecifications identified in the Burnside and Dollar approach on which this analysis is based; and are not grounded in any theoretical formulation about the special relation between aid and growth in post-conflict conditions. Conventional econometric procedures are often not followed; recoding the sample to exclude cases that are not civil wars reduces the effect of aid on growth in post-civil war countries to less than half of what they claim; and the difference with the relationship for "normal" countries becomes negligible (0.26 percentage points), although it depends on identification of the sample. Their claims on the poverty-efficiency of aid are assumed, not analysed. The confidentiality of their policy measure (CPIA) prevented testing the aid-policy relationship.Economic aid Post-conflict Methodology

Relevance of the slowly-varying electron gas to atoms, molecules, and solids

Under a certain scaling, the electron densities of finite systems become both large and slowly-varying, so that the gradient expansions of the density functionals for the Kohn-Sham kinetic and exchange energies become asymptotically exact to order $\nabla^2$. Neutral atoms of large $Z$ scale similarly, but a cusp correction at the nucleus requires generalizing the gradient expansion for exchange, producing the wrong gradient coefficient in the slowly-varying limit. Meta-generalized gradient approximations (meta-GGA's) recover both the slowly-varying and large-$Z$ limits. GGA correlation energies of large-Z atoms are found to be accurate.Comment: 5 pages, 4 figures, submitted at PR

Morphological and proteomic responses of Eruca sativa exposed to silver nanoparticles or silver nitrate

Silver nanoparticles (AgNPs) are widely used in commercial products, and there are growing concerns about their impact on the environment. Information about the molecular interaction of AgNPs with plants is lacking. To increase our understanding of the mechanisms involved in plant responses to AgNPs and to differentiate between particle specific and ionic silver effects we determined the morphological and proteomic changes induced in Eruca sativa (commonly called rocket) in response to AgNPs or AgNO3. Seedlings were treated for 5 days with different concentrations of AgNPs or AgNO3. A similar increase in root elongation was observed when seedlings were exposed to 10 mg Ag L-1 of either PVP-AgNPs or AgNO3. At this concentration we performed electron microscopy investigations and 2-dimensional electrophoresis (2DE) proteomic profiling. The low level of overlap of differentially expressed proteins indicates that AgNPs and AgNO3 cause different plant responses. Both Ag treatments cause changes in proteins involved in the redox regulation and in the sulfur metabolism. These responses could play an important role to maintain cellular homeostasis. Only the AgNP exposure cause the alteration of some proteins related to the endoplasmic reticulum and vacuole indicating these two organelles as targets of the AgNPs action. These data add further evidences that the effects of AgNPs are not simply due to the release of Ag ions

The skeletal phenotype of chondroadherin deficient mice

Chondroadherin, a leucine rich repeat extracellular matrix protein with functions in cell to matrix interactions, binds cells via their a2b1 integrin as well as via cell surface proteoglycans, providing for different sets of signals to the cell. Additionally, the protein acts as an anchor to the matrix by binding tightly to collagens type I and II as well as type VI. We generated mice with inactivated chondroadherin gene to provide integrated studies of the role of the protein. The null mice presented distinct phenotypes with affected cartilage as well as bone. At 3–6 weeks of age the epiphyseal growth plate was widened most pronounced in the proliferative zone. The proteome of the femoral head articular cartilage at 4 months of age showed some distinct differences, with increased deposition of cartilage intermediate layer protein 1 and fibronectin in the chondroadherin deficient mice, more pronounced in the female. Other proteins show decreased levels in the deficient mice, particularly pronounced for matrilin-1, thrombospondin-1 and notably the members of the a1-antitrypsin family of proteinase inhibitors as well as for a member of the bone morphogenetic protein growth factor family. Thus, cartilage homeostasis is distinctly altered. The bone phenotype was expressed in several ways. The number of bone sialoprotein mRNA expressing cells in the proximal tibial metaphysic was decreased and the osteoid surface was increased possibly indicating a change in mineral metabolism. Micro-CT revealed lower cortical thickness and increased structure model index, i.e. the amount of plates and rods composing the bone trabeculas. The structural changes were paralleled by loss of function, where the null mice showed lower femoral neck failure load and tibial strength during mechanical testing at 4 months of age. The skeletal phenotype points at a role for chondroadherin in both bone and cartilage homeostasis, however, without leading to altered longitudinal growth

Nitrogen uptake in plants: The plasma membrane root transport systems from a physiological and proteomic perspective

Nitrogen nutrition in plants is a key determinant in crop productivity. The availability of nitrogen nutrients in the soil, both inorganic (nitrate and ammonium) and organic (urea and free amino acids), highly differs and influences plant physiology, growth, metabolism, and root morphology. Deciphering this multifaceted scenario is mandatory to improve the agricultural sustainability. In root cells, specific proteins located at the plasma membrane play key roles in the transport and sensing of nitrogen forms. This review outlines the current knowledge regarding the biochemical and physiological aspects behind the uptake of the individual nitrogen forms, their reciprocal interactions, the influences on root system architecture, and the relations with other proteins sustaining fundamental plasma membrane functionalities, such as aquaporins and H+‐ ATPase. This topic is explored starting from the information achieved in the model plant Arabidopsis and moving to crops in agricultural soils. Moreover, the main contributions provided by proteomics are described in order to highlight the goals and pitfalls of this approach and to get new hints for future studies

"Economic Aid to Post-Conflict Countries: A Methodological Critique of Collier and Hoeffler"

This paper retests the analysis of “Aid Policy and Growth in Post-Conflict Societies,” by Paul Collier and Anke Hoeffler (October 2002 and forthcoming in European Economic Review). It finds that their data and analysis do not support their conclusions and policy recommendations on the optimal timing and amounts of aid. These conclusions depend on very few observations (13 for the period of peace-onset, 13 for years 4 to 7 when a growth spurt is said to make aid particularly effective, and 8 for the period when aid should taper off); are vulnerable to the same methodological misspecifications identified in the Burnside and Dollar approach on which this analysis is based; and are not grounded in any theoretical formulation about the special relation between aid and growth in post-conflict conditions. Conventional econometric procedures are often not followed; recoding the sample to exclude cases that are not civil wars reduces the effect of aid on growth in post-civil war countries to less than half of what they claim; and the difference with the relationship for “normal” countries becomes negligible (0.26 percentage points), although it depends on identification of the sample. Their claims on the poverty-efficiency of aid are assumed, not analysed. The confidentiality of their policy measure (CPIA) prevented testing the aid-policy relationship

Nitrogen starvation and nitrate or ammonium availability differently affect phenolic composition in green and purple basil

Basil (Ocimum basilicum L.) comprises green and purple cultivars, worldwide cultivated and appreciated for high contents of rosmarinic acid and anthocyanins, respectively. Although nitrogen (N) fertilization is needed for high yields, in basil it could have detrimental effects on the accumulation of phenolic compounds. In this study, plants of the cultivars 'Italiano Classico' (green) and 'Red Rubin' (purple) were grown in hydroponics and subjected to different nutritional treatments, consisting in N starvation, and nitrate (NO3 12) or ammonium (NH4+) nutrition. Plant growth and nutritional status, estimated by the contents of NO3 12, NH4+, and amino acids in roots and leaves, were evaluated and put in relation with quality traits of basil leaves, such as chlorophyll content, antioxidant capacity, total phenols, the activity of phenylalanine ammonia-lyase, and the concentrations of individual (poly)phenolic acids and flavonoids. This study reveals that N starvation, as well as the availability of the two inorganic N forms, differently affect the phenolic composition in the two cultivars. Compared to plants grown in NO3 12 availability, in NH4+ availability, green basil showed a higher content of (poly)phenolic acids, while in purple basil, an increase in the contents of anthocyanins was detected. Overall, the study suggests that the management of NH4+ supply could contribute to enhance crop quality in hydroponics, and provides new knowledge about the relationship between N nutrition and phenolic metabolism in basil

Cerebrovascular Casting of the Adult Mouse for 3D Imaging and Morphological Analysis

Vascular imaging is crucial in the clinical diagnosis and management of cerebrovascular diseases, such as brain arteriovenous malformations (BAVMs). Animal models are necessary for studying the etiopathology and potential therapies of cerebrovascular diseases. Imaging the vasculature in large animals is relatively easy. However, developing vessel imaging methods of murine brain disease models is desirable due to the cost and availability of genetically-modified mouse lines. Imaging the murine cerebral vascular tree is a challenge. In humans and larger animals, the gold standard for assessing the angioarchitecture at the macrovascular (conductance) level is x-ray catheter contrast-based angiography, a method not suited for small rodents

Insight into composition of bioactive phenolic compounds in leaves and flowers of green and purple basil

Basil (Ocimum basilicum L.) is a culinary, medicinal, and ornamental plant appreciated for its antioxidant properties, mainly attributed to high content of rosmarinic acid. This species also includes purple varieties, characterized by the accumulation of anthocyanins in leaves and flowers. In this work, we compared the main morphological characteristics, the antioxidant capacity and the chemical composition in leaves, flowers, and corollas of green (\u2018Italiano Classico\u2019) and purple (\u2018Red Rubin\u2019 and \u2018Dark Opal\u2019) basil varieties. The LC-ESI-MS/MS analysis of individual compounds allowed quantifying 17 (poly)phenolic acids and 18 flavonoids, differently accumulated in leaves and flowers of the three varieties. The study revealed that in addition to rosmarinic acid, basil contains several members of the salvianolic acid family, only scarcely descripted in this species, as well as, especially in flowers, simple phenolic acids, such as 4-hydroxybenzoic acid and salvianic acid A. Moreover, the study revealed that purple leaves mainly contain highly acylated anthocyanins, while purple flowers accumulate anthocyanins with low degree of decoration. Overall, this study provides new biochemical information about the presence of not yet characterized bioactive compounds in basil that could contribute to boosting the use of this crop and to gaining new knowledge about the roles of these compounds in plant physiology

Time-course of metabolic and proteomic responses to different nitrate/ammonium availabilities in roots and leaves of maize

The availability of nitrate and ammonium significantly affects plant growth. Co-provision of both nutrients is generally the best nutritional condition, due to metabolic interactions not yet fully elucidated. In this study, maize grown in hydroponics was exposed to different nitrogen (N) availabilities, consisting of nitrate, ammonium and co-provision. Roots and leaves were analyzed after 6, 30, and 54 h by biochemical evaluations and proteomics. The ammonium-fed plants showed the lowest biomass accumulation and the lowest ratio of inorganic to organic N content, suggesting a metabolic need to assimilate ammonium that was not evident in plants grown in co-provision. The N sources differently affected the root proteome, inducing changes in abundance of proteins involved in N and carbon (C) metabolisms, cell water homeostasis, and cell wall metabolism. Notable among these changes was that some root enzymes, such as asparagine synthetase, phosphoenolpyruvate (PEP) carboxylase, and formate dehydrogenase showed a relevant upsurge only under the sole ammonium nutrition. However, the leaf proteome appeared mainly influenced by total N availability, showing changes in the abundance of several proteins involved in photosynthesis and in energy metabolism. Overall, the study provides novel information about the biochemical determinants involved in plant adaptation to different N mineral forms