A Comparison of Grassland Management Systems for Beef Cattle Using Self-Contained Farmlets: Effects of Contrasting Nitrogen Inputs and Management Strategies on the Farm Economy

The financial implications of manipulating nitrogen (N) inputs and management strategies for beef production systems were assessed. One-hectare grassland farmlets were grazed to a target sward height by beef steers; herbage surplus to grazing requirements was cut for silage. Three systems were compared: ‘CN’, conventional mineral N application to a grass monoculture and broadcast slurry; ‘TN’, tactical mineral N application at fortnightly intervals to a grass monoculture with slurry injection and the early housing of cattle; ‘GC’, a mixed grass/white clover sward with no mineral N addition and slurry injection. Comparisons were made on two contrasting soil types: a freely-draining sandy loam (site 1) and a poorly drained clay (site 2). Financial budgets for 1999-2000 show that estimated gross profit margins (gross outputs minus variable costs), after deducting contractor’s charges for sward preparation and fertiliser spreading, were highest for treatment CN at both sites Î(€1552, €1356 and €1461 ha-1 for site 1 and €1562, €1281 and €1287 ha-1 for site 2, for treatments CN, TN and GC, respectively). Treatment TN was penalised by increased costs associated with an extended housed period and the need to purchase additional silage for winter feeding which cost €242 ha-1 at site 1 and €250 ha-1 at site 2. Savings in N fertiliser for TN in comparison with CN (€44 ha-1 at site 1 and €39 ha-1 at site 2) were more than offset by the increased costs of fortnightly fertiliser applications (€54 ha-1 at site 1 and €46 ha-1 at site 2). Treatment GC benefited from zero costs for the purchase and spreading of mineral N fertiliser but was penalised by increased variation in forage DM production which resulted in a shortfall in winter fodder requirements with a replacement cost of €250 at site 1 and €435 at site 2. The best overall economic performance after the allocation of all possible relevant costs (variable, fixed and capital) in terms of the relative net profit margin, was for GC at site 1 and for CN at site 2 (-€1358, -€2399 and -€1304 ha-1 at site 1 and -€1122, -€2810 and - €1380 ha-1 at site 2, for CN, TN and GC, respectively). The opportunity costs of reducing N surpluses at the gross profit margin level (after contractor’s charges) for treatments TN and GC over treatment CN were calculated at €2.29 kg-1 N surplus for TN and €0.67 kg-1 N surplus for GC at site 1, with corresponding values of €4.91 and €1.57 at site 2.Farmlets, Systems, Beef cattle, Nitrogen, Slurry, Animal production, Economics, UK, Farm Management,

Educating a syndrome? Seeking a balance between identifying a learning profile and delivering inclusive education

This article summarizes research related to pedagogical approaches to special education, and characteristics of teacher's attitudes and beliefs that supports effective inclusion practices. Additionally, the author summarizes factors that may both enable and disable children with DS's progress, and notes speech and language characteristics from research to date

Electromagnetic wave propagation in rain and polarization effects

This paper summarizes our study on microwave and millimeter-wave propagation in rain with special emphasis on the effects of polarization. Starting from a recount of our past findings, we will discuss developments with these and how they are connected with subsequent research

A Thermodynamically-Based Mesh Objective Work Potential Theory for Predicting Intralaminar Progressive Damage and Failure in Fiber-Reinforced Laminates

A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Damage is considered to be the effect of any structural changes in a material that manifest as pre-peak non-linearity in the stress versus strain response. Conversely, failure is taken to be the effect of the evolution of any mechanisms that results in post-peak strain softening. It is assumed that matrix microdamage is the dominant damage mechanism in continuous fiber-reinforced polymer matrix laminates, and its evolution is controlled with a single ISV. Three additional ISVs are introduced to account for failure due to mode I transverse cracking, mode II transverse cracking, and mode I axial failure. Typically, failure evolution (i.e., post-peak strain softening) results in pathologically mesh dependent solutions within a finite element method (FEM) setting. Therefore, consistent character element lengths are introduced into the formulation of the evolution of the three failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs is derived. The theory is implemented into commercial FEM software. Objectivity of total energy dissipated during the failure process, with regards to refinements in the FEM mesh, is demonstrated. The model is also verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared to the experiments

First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology

Abstract The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed

A Comparison of Grassland Management Systems for Beef Cattle Using Self-Contained Farmlets: Effects of Contrasting Nitrogen Inputs and Management Strategies on the Farm Economy

The financial implications of manipulating nitrogen (N) inputs and management strategies for beef production systems were assessed. One-hectare grassland farmlets were grazed to a target sward height by beef steers; herbage surplus to grazing requirements was cut for silage. Three systems were compared: ‘CN’, conventional mineral N application to a grass monoculture and broadcast slurry; ‘TN’, tactical mineral N application at fortnightly intervals to a grass monoculture with slurry injection and the early housing of cattle; ‘GC’, a mixed grass/white clover sward with no mineral N addition and slurry injection. Comparisons were made on two contrasting soil types: a freely-draining sandy loam (site 1) and a poorly drained clay (site 2). Financial budgets for 1999-2000 show that estimated gross profit margins (gross outputs minus variable costs), after deducting contractor’s charges for sward preparation and fertiliser spreading, were highest for treatment CN at both sites Î(€1552, €1356 and €1461 ha-1 for site 1 and €1562, €1281 and €1287 ha-1 for site 2, for treatments CN, TN and GC, respectively). Treatment TN was penalised by increased costs associated with an extended housed period and the need to purchase additional silage for winter feeding which cost €242 ha-1 at site 1 and €250 ha-1 at site 2. Savings in N fertiliser for TN in comparison with CN (€44 ha-1 at site 1 and €39 ha-1 at site 2) were more than offset by the increased costs of fortnightly fertiliser applications (€54 ha-1 at site 1 and €46 ha-1 at site 2). Treatment GC benefited from zero costs for the purchase and spreading of mineral N fertiliser but was penalised by increased variation in forage DM production which resulted in a shortfall in winter fodder requirements with a replacement cost of €250 at site 1 and €435 at site 2. The best overall economic performance after the allocation of all possible relevant costs (variable, fixed and capital) in terms of the relative net profit margin, was for GC at site 1 and for CN at site 2 (-€1358, -€2399 and -€1304 ha-1 at site 1 and -€1122, -€2810 and - €1380 ha-1 at site 2, for CN, TN and GC, respectively). The opportunity costs of reducing N surpluses at the gross profit margin level (after contractor’s charges) for treatments TN and GC over treatment CN were calculated at €2.29 kg-1 N surplus for TN and €0.67 kg-1 N surplus for GC at site 1, with corresponding values of €4.91 and €1.57 at site 2