Comparing the Effects of Conventional and Pastured Poultry Production Systems on the Stress Levels of Broilers

Abstract The objective of this study was to measure stress levels in broilers raised on a pasture production system (PPS) and a conventional production system (CPS) by evaluating lymphoid organ weights, white blood cell profiles (WBCP), total white blood cell counts (TWBC), and heterophil to lymphocyte ratios (HLR). Broilers were brooded indoors for 3 weeks then divided into 2 groups; one placed on pasture while the other remained indoors. Blood was collected at weeks 3, 5, and 7 via brachial venipuncture. After 49 days, birds were slaughtered and lymphoid organs harvested. Results showed no differences between treatments for lymphoid organs, TWBC, or WBCP. Eosinophils were higher (P \u3c 0.05) in CPS (333.33) compared to PPS birds (148.00) at week 5. The HLR was lower (P \u3c 0.05) in PPS broilers at week 5 (0.40) than weeks 3 (0.44) and 7 (0.43). The PPS broilers experienced less stress overall than CPS birds. Keywords: Conventional Production System, Broilers, Pasture Production System, Stres

Students' difficulties, conceptions and attitudes towards learning algebra : an intervention study to improve teaching and learning

The skills necessary to identify and analyse errors and misconceptions made by students are needed by teachers of all levels especially at the lower secondary school level in Malaysia. If students are to be successful in tackling mathematical problems later in their schooling, the one prerequisite is the mastery of basic concepts in algebra. Despite the best efforts of the teachers, students still develop algebra misconceptions. Is it possible to reduce or eliminate these misconceptions? The research involved a survey of 14 year-old students in Form 2 (Grade 8) in the Penampang district of Sabah, East Malaysia. The focus of this study lies in students’ difficulties, conceptions and attitudes towards learning algebra in the framework of conceptual change. A possible way to help students overcome their learning difficulties and misconceptions is by implementing diagnostic teaching involving conflict to foster conceptual change. The study involved evaluating the efficacy of a conceptual change instructional programme involving cognitive conflict in (1) facilitating Form 2 students’ understanding of algebra concepts, and (2) assessing changes in students’ attitudes towards learning mathematics, in a mixed quantitativequalitative research design.A 24-item Algebra Diagnostic Test and a 20-item Test of Mathematics-Related Attitudes (TOMRA) questionnaire were administered as a pretest and a posttest to 39 students in each of a heterogeneous high-achieving class and a below-average achieving class. In addition 9 students were purposefully selected to participate in the interview.The results of the study indicated that students’ difficulties and misconceptions from both classes fell into five broad areas: (1) basic understanding of letters and their place in mathematics, (2) manipulation of these letters or variables, (3) use of rules of manipulation to solve equations, (4) use of knowledge of algebraic structure and syntax to form equations, and (5) generalisation of rule for repetitive patterns or sequences of shapes.The results also showed that there was significant improvement in students’ achievement in mathematics. Further, students’ attitude towards inquiry of mathematics lessons showed significant positive improvement. Enjoyment remained high even though enjoyment of mathematics lesson showed no change. Also, changes in students’ understanding (from unintelligible to intelligible, intelligible to plausible, plausible to fruitful) illustrated the extent of changes in their conceptions.Different pedagogies can affect how conceptual change and challenge of misconceptions occurs. Therefore, knowledge of the origin of different types of misconceptions can be useful in selecting more effective pedagogical techniques for challenging particular misconceptions. Also, for teachers to create an effective learning experience they should be aware of and acknowledge students’ prior knowledge acquired from academic settings and from everyday previous personal experiences. Since all learning involves transfer from prior knowledge and previous experiences, an awareness and understanding of a student’s initial conceptual framework and/or topic can be used to formulate more effective teaching strategies. If this idea is taken a step further, it could be said that, because misconceptions comprise part of a conceptual framework, then understanding origins of misconceptions would further facilitate development of effective teaching strategies.Further research is needed to help teachers to understand how students experience conflict, how students feel when they experience conflict, and how these experiences are related to their final responses because cognitive conflict has both constructive and destructive potential. Thus, by being able to interpret, recognise and manage cognitive conflict, a teacher can then successfully interpret his/her students’ cognitive conflict and be able to make conceptual change more likely or help students to have meaningful learning experiences in secondary school algebra

Evaluating the Economic Feasibility of Producing Broilers on Pasture and in a Conventional Production System

The demand for pasture raised poultry is increasing because of the perception that it is healthier and tastier than conventionally raised poultry. In order to meet this demand, some producers are considering switching from the conventional to the pasture system to take advantage of this niche market. Therefore, the objective of the study was to determine the economic viability of rearing broilers in a pastured poultry system (PPS) versus a conventional poultry system (CPS). Each of these systems was replicated three times with 60 birds per treatment in a study lasting seven weeks. Data were collected on costs of inputs, and others estimated. The mean net returns for PPS and CPS were, respectively, $56.44 and -$92.02. The break-even prices were, respectively, $10.89 for PPS and$11.87 for CPS. Also, the benefit/cost ratio was 1.103 for PPS and 0.845 for CPS. The paired t-test for the benefit/cost ratios indicated a significant difference (p< 0.05) between PPS and CPS. PPS was deemed more feasible than CPS. Hence, it was recommended that the former system is more appropriate for small and limited resource producers, and that technical assistance should be provided to them regarding PPS. Keywords: Pastured poultry, Conventional poultry, Economic feasibility, Broiler

Nonconsumptive Effects of Crustaceans and an Echinoderm on Spat of the Eastern Oyster Crassostrea virginica (Gmelin, 1791)

Predation by crustaceans and echinoderms is a significant driver of mortality for sessile invertebrates in near-shore marine ecosystems. As a response, shellfish growers use predator exclusion cages to grow their product. Oysters grown in these cages and clams in and under nets have been observed to exhibit thinner, brittle shells, which is not optimal for market, nor for those being grown for restoration purposes. Here, the nonconsumptive predator effects of several native and nonnative predators on shell morphology of Crassostrea virginica oyster spat. Juvenile (1–3 mm) seed oysters were exposed separately to chemical cues of five different predators and one nonpredator crab were investigated and compared with control (no exposure) spat. Significant effects of predator presence on the total wet weight (g) of the spat was demonstrated, with the highest increase for spat exposed to black-fingered mud crabs (Panopeus, 1.70 mg d−1) and the biggest decreases for spat exposed to the European green crabs (Carcinus maenas—1.34 mg d−1) and the sea stars (Asterias rubens—1.47 mg d−1). Changes to oyster length (mm) and shell density (crushing resistance) were not significant. Implications for aquaculturists and wild bivalve populations are that growth could be negatively affected by the lack of predators on these important organisms

Sirolimus-induced Pneumonitis Complicated by Pentamidine-induced Phospholipidosis in a Renal Transplant Recipient: A Case Report.

The proliferation signal inhibitors (PSIs)-sirolimus, everolimus, and temsirolimus-have been associated with a noninfectious pneumonitis characterized by lymphocytic alveolitis and bronciolitis obliterans with organizing pneumonia (BOOP). This condition usually occurs within the first year. Herein we presented a case of a deceased donor renal transplant with interstitial pneumonitis developing 6 years after a switch from tacrolimus to sirolimus due to chronic graft dysfunction. After the addition of intravenous pentamidine due to the suspicion of Pneumocystis pneumonia, there was marked clinical deterioration requiring intubation. Open lung biopsy revealed sirolimus-induced pulmonary toxicity (BOOP) with the additional finding of a drug-induced phospholipidosis (DIPL) that we ascribe to pentamidine treatment. After cessation of both drugs and application of corticosteroid therapy, there was only partial improvement. Eight months later the residual interstitial fibrosis demands supplemental home oxygen. We review the literature on PSI-induced pneumonitis and discuss the pathophysiology of a potential interaction with pentamidine. We caution against its use in the setting of PSI-induced pneumonitis. It is currently unknown whether these concerns also apply to prescription of other more commonly used medications associated with DIPL, eg, amiodarone and aminoglycosides

Near-Infrared Imaging Polarimetry of Young Stellar Objects in rho-Ophiuchi

The results of a near-infrared (J H K LP) imaging linear polarimetry survey of 20 young stellar objects (YSOs) in rho Ophiuchi are presented. The majority of the sources are unresolved, with K-band polarizations, P_K < 6 per cent. Several objects are associated with extended reflection nebulae. These objects have centrosymmetric vector patterns with polarization discs over their cores; maximum polarizations of P_K > 20 per cent are seen over their envelopes. Correlations are observed between the degree of core polarization and the evolutionary status inferred from the spectral energy distribution. K-band core polarizations >6 per cent are only observed in Class I YSOs. A 3D Monte Carlo model with oblate grains aligned with a magnetic field is used to investigate the flux distributions and polarization structures of three of the rho Oph YSOs with extended nebulae. A rho proportional to r^(-1.5) power law for the density is applied throughout the envelopes. The large-scale centrosymmetric polarization structures are due to scattering. However, the polarization structure in the bright core of the nebula appears to require dichroic extinction by aligned non-spherical dust grains. The position angle indicates a toroidal magnetic field in the inner part of the envelope. Since the measured polarizations attributed to dichroic extinction are usually <10 per cent, the grains must either be nearly spherical or very weakly aligned. The higher polarizations observed in the outer parts of the reflection nebulae require that the dust grains responsible for scattering have maximum grain sizes <=1.05 microns.Comment: 26 pages. Accepted by MNRAS. Available as online early versio

Towards a better understanding of global land grabbing: an editorial introduction

ESR