The Economic Returns to Membership of a Dairy Discussion Group: Evidence from the Irish National Farm Survey

In December 2009 the Irish Department of Agriculture launched the Dairy Efficiency Programme. The Programme, which is operated through a series of discussion groups, is designed to promote technology transfer to dairy farmers. Drawing on National Farm Survey data from 2009, the purpose of this paper is to quantify the economic return to membership of dairy discussion groups. An endogenous switching regression model is specified for over 300 dairy farms to assess the impact of discussion group participation on farm gross margins. The results indicate self-selection into discussion groups, suggesting that „better‟ farmers tend to participate. Generally, younger farmers who operate larger farms are more likely to join discussion groups. Discussion group members have higher gross margins than non-members, but non-members could increase their gross margins if they join discussion groups. Overall, the findings confirm positive returns to discussion group membership, thus supporting the Dairy Efficiency Programme.Endogenous switching regression model, Discussion group membership, Dairy Efficiency Programme, Livestock Production/Industries,

Mathematical Modelling of Tyndall Star Initiation

The superheating that usually occurs when a solid is melted by volumetric heating can produce irregular solid-liquid interfaces. Such interfaces can be visualised in ice, where they are sometimes known as Tyndall stars. This paper describes some of the experimental observations of Tyndall stars and a mathematical model for the early stages of their evolution. The modelling is complicated by the strong crystalline anisotropy, which results in an anisotropic kinetic undercooling at the interface; it leads to an interesting class of free boundary problems that treat the melt region as infinitesimally thin

The role of financing frictions in agricultural investment decisions: an analysis pre and post financial crisis

This paper uses a fundamental Q model of investment to consider the role played by financing frictions in agricultural investment decisions, controlling econometrically for censoring, heterogeneity and errors-in-variables. Our findings suggest that farmer's investment decisions are not driven by market fundamentals. We find some evidence that debt overhang restricts investment but investment is not dependent on liquidity or internal funds. The role of financing frictions in determining investment decisions changes in the post-financial crisis period when debt overhang becomes a significant impediment to farm investment. The evidence suggests that farmers increasingly rely on internal liquidity to drive investment. Finally, we find no evidence that farmers use on-farm capital to fund on-farm investment.Credit Constraints, Firm Level Investment, Tobin's Q, Debt, Agricultural Finance, G31, G32, F34,

A Calculus of Bounded Capacities

Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

Ensuring behavioural equivalence in test-driven porting

In this paper we present a test-driven approach to porting code from one object-oriented language to another. We derive an order for the porting of the code, along with a testing strategy to verify the behaviour of the ported system at intra and inter-class level. We utilise the recently defined methodology for porting C++ applications, eXtreme porting, as a framework for porting. This defines a systematic routine based upon porting and unit-testing classes in turn. We augment this approach by using Object Relation Diagrams to define an order for porting that minimises class stubbing. Since our strategy is class-oriented and test-driven, we can ensure the structural equivalence of the ported system, along with the limited behavioural equivalence of each class. In order to extend this to integration-level equivalence, we exploit aspect-oriented programming to generate UML sequence diagrams, and we present a technique to compare such automatically-generated diagrams for equivalence. We demonstrate and evaluate our approach using a case study that involves porting an application from C++ to Java

Ensuring behavioural equivalence in test-driven porting

In this paper we present a test-driven approach to porting code from one object-oriented language to another. We derive an order for the porting of the code, along with a testing strategy to verify the behaviour of the ported system at intra and inter-class level. We utilise the recently defined methodology for porting C++ applications, eXtreme porting, as a framework for porting. This defines a systematic routine based upon porting and unit-testing classes in turn. We augment this approach by using Object Relation Diagrams to define an order for porting that minimises class stubbing. Since our strategy is class-oriented and test-driven, we can ensure the structural equivalence of the ported system, along with the limited behavioural equivalence of each class. In order to extend this to integration-level equivalence, we exploit aspect-oriented programming to generate UML sequence diagrams, and we present a technique to compare such automatically-generated diagrams for equivalence. We demonstrate and evaluate our approach using a case study that involves porting an application from C++ to Java

Geochemistry of Ordovician black shales at Meductic, southern Miramichi Highlands, New Brunswick

The geochemistry of black shales is useful for identifying geological events such as anoxia, for predicting the proximity of submarine hydrothermal springs and associated mineral deposits, and for indicating the existence of mineral deposits in precursor terrains. In the Miramichi Highlands of New Brunswick, large massive sulfide deposits occur in a mid-Ordovician (Llanvirnian) sequence of felsic volcanic and sedimentary rocks of the Tetagouche Group, disconformably overlying relatively monotonous quartzose wacke and grey-green shale of the Miramichi Group. Black shales commonly occur at the boundary between the Miramichi and Tetagouche groups, and in some areas such as at Meductic in the southern Miramichi Highlands, they display high heavy metal values in common with Scandinavian-Caledonide black shales. Like the massive sulphide deposits, the Meductic metalliferous black shales were deposited in a back-arc basin associated with an island-arc system formed during the closing of the proto-Atlantic Ocean and the onset of the Taconian orogeny. The average Meductic black shale, as deduced from the Bright Eye Brook Formation at the base of the Tetagouche Group, shows high values of V and Ba, moderate enrichment in Nb, Th, Pb, Ti, and Crf and depletion in Sr, Cu and Ni compared to black shale USGS standard SDO-1. Total organic carbon is well above the minimum value for a carbonaceous shale, the highest value (2.35%) corresponding to highest V (3016 ppm) and highest Ba (16,173 ppm). CaO, Fe2O3 and MnO contents are low, and SiO2, K2O and P2O5 contents are relatively high compared to the standard. Chondrite-normalized REE patterns show elevated LREE, fairly flat HREE signatures, a negative Eu anomaly and a slightly positive Cc anomaly. These features are characteristic of marine volcanological detrital input rather than a hydrothermal regime. Correlation of high V with Ba indicates that conditions were favourable for deposition of both metals. It is postulated that early deposition in an oxic environment (higher than normal MnO) was succeeded by gradual stagnation (increasing levels of V). Concomitant enrichment in Ba under anoxic conditions was linked to a regime of elevated heat flow. This scenario is compatible with the record of sea level fluctuations during the early Palaeozoic. RÉSUMÉ L'analyse géochimique des schistes noirs permet de deceler des phénomènes géologiques comme l'anoxie, qui annonce la proximité de sources hydrothermales sous-marines et de gites minéraux connexes et qui révèle l'existence de gttes minéraux dans des terrains précurseurs. Dans les hautes terres de Miramichi, au Nouveau-Brunswick, on relève des gisements de sulfures massifs importants dans une séquence de l'Ordovicien moyen (Llanvirnien) de roches sédimentaires et volcanofelsiques du groupe de Tetagouche qui recouvrent de fa÷on discordante des wackes quartzeuses relativement monotones et des schistes gris-vert du groupe de Miramichi. On trouve couramment des schistes noirs le long de la frontière séparant les groupes de Miramichi et de Tetagouche; de plus, dans certains secteurs, comme eclui de Meductic, dans le sud des hautes terres de Miramichi, les schistes noirs affichent, en commun avec des schistes noirs scandinaviens-calédoniens, des valeurs élevées de métaux lourds. À l'instar des gisements de sulfures massifs, les schistes noirs métalliferes de Meductic se sont déposés dans des bassins arrière-arcs associés a un système d'arcs insulaires formé lors de la fermeture de l'ocean proto-atlantique et au début de l'orogenèse taconique. Les schistes noirs de Meductic moyens, d'après ce qu'on en déduit de la Formation de Bright Eye Brook à labase du groupe de Tetagouche, affichent des valeurs élevéens de V et de Ba, un enrichissement moyen en Nb, Th,Pb, Ti et Cr, ainsi qu'une réduction de Sr, de Cu et de Ni, comparativement à la norme SDO-1 du USGS. Lecarbone organique total se situé bien au-dessus de la valcur minimale d'un schiste charbonneux, la valeur la plus élevée (2,35 %) correspondant aux teneurs les plus élevées en V (3 016 mg/kg) et en Ba (16 173 mg/kg). Lesteneurs en CaO, Fe2O3 et en MnO sont basses et celles en SiO2, K2O et P2O5 sont relativement élevées comparativementaux teneurs normales. Les modeles d'ETR réduits en chondrites affichent des quantités élevées d'éléments deterres rares legers, des signatures d'éléments de terres rares lourds passablement uniformes, une anomalie négatived'Eu et une anomalie légèrement positive de Ce. Ces traits sont caractéristiques d'un apport détritique volcanologiquemarin ptutôt que d'un régime hydrothermal. La corrélation de valeurs élevées de V et de B revéle que les conditions étaient propices à la sédimentation des deux métaux. On suppose qu'une sédimentation précoce dans unmilieu oxique (présence de MnO supérieure à la normale) a été suivie par une stagnation graduelle (nivcaux croissants de V). On a relié l'enrichissement concomitant en Ba dans des conditions anoxiques à un régime deflux thermique élevé. Ce scénario est compatible avec les fluctuations du niveau de la mer enregistrées au coursdu Paléozoique inférieur. [Traduit par la réedaction