Phosphorus feeding practices, barriers to and motivators for minimising phosphorus feeding to dairy cows in diverse dairy farming systems.

Minimising phosphorus (P) feeding to dairy cows can reduce feed costs and minimise water pollution without impairing animal performance. This study aimed to determine current P feeding practices and identify the barriers to and motivators for minimising P feeding on dairy farms, using Great Britain (GB) dairy farming as an example of diverse systems. Farmers (n = 139) and feed advisers (n = 31) were involved simultaneously in independent questionnaire surveys on P feeding in dairy farms. Data on the herd size, milk yield and concentrate fed were analysed using ANOVA to investigate the effect of farm classification, region, and feed professional advice. Chi-square tests were used to investigate associations between farm characteristics and implemented P feeding and management practices. Most farmers (72%) did not know the P concentration in their lactating cow's diet and did not commonly adopt precision P feeding practices, indicating that cows might have been offered dietary P in excess of recommended P requirement. Farmers' tendency to feed P in excess of recommendations increased with herd size, but so did their awareness of P pollution issues and likeliness of testing manure P. However, 68% of farmers did not analyse manure P, indicating that mineral P fertiliser application rates were not adjusted accordingly, highlighting the risk of P being applied beyond crops' requirement. Almost all farmers (96%) were willing to lower dietary P concentration but the uncertainty of P availability in feed ingredients (30%) and concerns over reduced cow fertility (22%) were primary barriers. The willingness to reduce dietary P concentrations was driven by the prospect of reducing environmental damage (28%) and feed costs (27%) and advice from their feed professionals (25%). Most farmers (70%) relied on a feed professional, and these farmers had a higher tendency to analyse their forage P. However, farmers of pasture-based systems relied less on feed professionals. Both farmers (73%) and feed advisers (68%) were unsatisfied with the amount of training on P management available. Therefore, the training on P management needs to be more available and the influence that feed professionals have over P feeding should be better utilised. Study findings demonstrate the importance of considering type of dairy farming systems when developing precision P feeding strategies and highlight the increasing importance of feed professionals in minimising P feeding.

A comparison of student motivation in selecting bachelors of nursing or paediatric nursing at an Italian university.

AIM: To investigate students' reasons for choosing general or paediatric nursing, and to compare motivation factors and personal characteristics between the two professions. BACKGROUND: In Italy, nursing students can choose between two distinct career paths: general and paediatric nursing. However, it is unclear what factors motivate a student to choose between these two pathways. METHODS: A cross-sectional approach was used to compare a sample of general and paediatric nursing students enrolled in a university in northeast Italy. We administered a questionnaire that covered socio-demographic characteristics and included an instrument of motivation developed by Zysberg & Berry to 224 students enrolled in the 3-year classes. RESULTS: We analysed 215 questionnaires (96%). Paediatric nurses were generally younger, had attended a college preparatory high school and had previously failed another university programme. Many students, in both groups, had a relative who was a nurse, or had cared for a sick friend or family member. Students did not vary significantly in how they evaluated items included in the questionnaire. CONCLUSION: A career in nursing should be advised for students who are motivated to help other people. Paediatric nursing was identified as an acceptable career choice by students of college preparatory high schools or by students who had initially enrolled in a different university programme. General nursing was a satisfactory choice by students with previous work experience.

Peripapillary fundus perimetry in eyes with glaucoma.

AIMS: To evaluate, with fundus perimetry, the peripapillary differential light threshold (DLT) in eyes with glaucoma and ocular hypertension (OHT), and compare it with peripapillary retinal nerve fibre layer (RNFL) thickness. METHODS: 35 glaucomatous, 29 OHT and 24 control eyes were included. Peripapillary DLT at 1 degrees from the optic nerve head was quantified with fundus perimetry; peripapillary RNFL thickness was measured over the same area by optical coherence tomography. RESULTS: Mean (SD) peripapillary DLT was 19.2 (1.7), 17.6 (4.2) and 10.1 (6.9) dB in control, OHT and glaucomatous eyes, respectively (p<0.001). Mean (SD) RNFL thickness was 98.4 (35.3), 83.9 (35.1) and 55.8 (28.2) microm, respectively (p<0.001). Mean peripapillary DLT showed higher sensitivity and specificity in differentiating the three groups compared with RNFL thickness. CONCLUSION: Progressive, significant reduction of peripapillary DLT was documented in OHT and glaucomatous eyes compared with controls (p<0.001). DLT reduction parallels RNFL reduction.

Ant-based clustering and topographic mapping.

Ant-based clustering and sorting is a nature-inspired heuristic first introduced as a model for explaining two types of emergent behavior observed in real ant colonies. More recently, it has been applied in a data-mining context to perform both clustering and topographic mapping. Early work demonstrated some promising characteristics of the heuristic but did not extend to a rigorous investigation of its capabilities. We describe an improved version, called ATTA, incorporating adaptive, heterogeneous ants, a time-dependent transporting activity, and a method (for clustering applications) that transforms the spatial embedding produced by the algorithm into an explicit partitioning. ATTA is then subjected to the most rigorous experimental evaluation of an ant-based clustering and sorting algorithm undertaken to date: we compare its performance with standard techniques for clustering and topographic mapping using a set of analytical evaluation functions and a range of synthetic and real data collections. Our results demonstrate the ability of ant-based clustering and sorting to automatically identify the number of clusters inherent in a data collection, and to produce high quality solutions; indeed, we show that it is particularly robust for clusters of differing sizes and for overlapping clusters. The results obtained for topographic mapping are, however, disappointing. We provide evidence that the solutions generated by the ant algorithm are barely topology-preserving, and we explain in detail why results have--in spite of this--been misinterpreted (much more positively) in previous research.

Inspiration for optimization from social insect behaviour.

Research in social insect behaviour has provided computer scientists with powerful methods for designing distributed control and optimization algorithms. These techniques are being applied successfully to a variety of scientific and engineering problems. In addition to achieving good performance on a wide spectrum of 'static' problems, such techniques tend to exhibit a high degree of flexibility and robustness in a dynamic environment.

Ant algorithms for discrete optimization.

This article presents an overview of recent work on ant algorithms, that is, algorithms for discrete optimization that took inspiration from the observation of ant colonies' foraging behavior, and introduces the ant colony optimization (ACO) metaheuristic. In the first part of the article the basic biological findings on real ants are reviewed and their artificial counterparts as well as the ACO metaheuristic are defined. In the second part of the article a number of applications of ACO algorithms to combinatorial optimization and routing in communications networks are described. We conclude with a discussion of related work and of some of the most important aspects of the ACO metaheuristic.

Ant colonies for the travelling salesman problem.

We describe an artificial ant colony capable of solving the travelling salesman problem (TSP). Ants of the artificial colony are able to generate successively shorter feasible tours by using information accumulated in the form of a pheromone trail deposited on the edges of the TSP graph. Computer simulations demonstrate that the artificial ant colony is capable of generating good solutions to both symmetric and asymmetric instances of the TSP. The method is an example, like simulated annealing, neural networks and evolutionary computation, of the successful use of a natural metaphor to design an optimization algorithm.

Ant system: optimization by a colony of cooperating agents.

An analogy with the way ant colonies function has suggested the definition of a new computational paradigm, which we call ant system (AS). We propose it as a viable new approach to stochastic combinatorial optimization. The main characteristics of this model are positive feedback, distributed computation, and the use of a constructive greedy heuristic. Positive feedback accounts for rapid discovery of good solutions, distributed computation avoids premature convergence, and the greedy heuristic helps find acceptable solutions in the early stages of the search process. We apply the proposed methodology to the classical traveling salesman problem (TSP), and report simulation results. We also discuss parameter selection and the early setups of the model, and compare it with tabu search and simulated annealing using TSP. To demonstrate the robustness of the approach, we show how the ant system (AS) can be applied to other optimization problems like the asymmetric traveling salesman, the quadratic assignment and the job-shop scheduling. Finally we discuss the salient characteristics-global data structure revision, distributed communication and probabilistic transitions of the AS.

Behavior analysis and training-a methodology for behavior engineering.

We propose Behavior Engineering as a new technological area whose aim is to provide methodologies and tools for developing autonomous robots. Building robots is a very complex engineering enterprise that requires the exact definition and scheduling of the activities which a designer, or a team of designers, should follow. Behavior Engineering is, within the autonomous robotics realm, the equivalent of more established disciplines like Software Engineering and Knowledge Engineering. In this article we first give a detailed presentation of a Behavior Engineering methodology, which we call Behavior Analysis and Training (BAT), where we stress the role of learning and training. Then we illustrate the application of the BAT methodology to three cases involving different robots: two mobile robots and a manipulator. Results show the feasibility of the proposed approach.

Collagen shields delivery of netilmicin: a study of ocular pharmacokinetics.

Collagen shields have been used as therapeutic contact lenses to promote corneal epithelial healing and to deliver hydrosoluble drugs. In albino rabbits, we studied the ocular pharmacokinetics of netilmicin, an aminoglycoside antibiotic, released by a 24-hour collagen shield immersed for 10 min in commercially available eye solution of netilmicin, at the standard concentration of 3 mg/ml. The animals were sacrificed after 0.5, 1, 6 and 18 h. The antibiotic concentrations were measured by the microbiological method. The drug levels remained above the MIC for the usual pathogens for 18 h in the cornea and for 6 h in the aqueous humor. In the iris and ciliary body the peak concentration was reached 1 h after shield application, netilmicin concentration decreased thereafter rapidly. The lens and the vitreous did not appear to be permeated by the drug. In the conjunctiva, drug concentrations were low, showing a negligible lateral diffusion of netilmicin released by shields. In conclusion, our findings show, that if the collagen shields are used as delivery systems, a very concentrated drug solution is not required to obtain high and persistent levels of netilmicin in cornea.

Influence of carteolol and timolol on IOP an visual fields in glaucoma: a multi-center, double-masked, prospective study.

The influences of Carteolol and Timolol eye drops on intraocular pressure (IOP) and visual fields were compared in a multi-center, double-masked, prospective study. Two-hundred and forty eyes of 120 patients were initially included in the study, and 142 eyes of 72 patients fulfilled all the criteria for final statistical analysis. Both drugs significantly reduced IOP. The visual fields in both treatment groups did not change during one year of treatment. In both groups some patients improved slightly, and others deteriorated slightly. This indicates that locally applied beta-blockers may efficiently stop further progression of visual field defects in cases with increased IOP and early visual field damage. There was no difference between Carteolol and Timolol in this regard. The side effects were minimal, and there were no differences in their frequency or intensity in the two treatment groups.

Cardiovascular effects of befunolol, betaxolol and timolol eye drops.

A double-blind cross-over study was carried out on 15 glaucoma patients so as to verify the effects of three the beta blockers, beta-1 selective betaxolol, non-selective timolol and befunolol an agent with intrinsic sympathomimetic activity on the heart rate, monitored by a Holter apparatus, and with the blood pressure measured in standing and supine positions before and after eight days of topical therapy. The results showed that timolol induced a significant decrease in minimum heart rate (-4.2 +/- 2.9) (p less than 0.001) and in diastolic blood pressure in standing position (-8.0 +/- 12.5 mmHg) (p less than 0.05), betaxolol decreased systolic pressure in orthostatism (-7.5 +/- 12.3 mmHg) and in clinostatism (-12.1 +/- 16.2 mmHg) and diastolic pressure in orthostatism (-6.25 +/- 9.4 mmHg) (p less than 0.05). Befunolol alone did not alter the heart rate or blood pressure.

Contribution of manual and computerized perimetry to the differential diagnosis of optic neuropathies.

The contribution given by manual perimetry to differential diagnosis of optic neuropathies is described. The advantages and the disadvantages of automated perimetry in respect to manual perimetry are examined. The programs to use for a more precise diagnosis and according to different pathology are also examined. The problems connected to perimetric interpretation are discussed. The value of global indices in evaluating the visual field as well as the importance of statistical program in comparing more than one test performed are reported. The review stresses the usefulness of automated perimetry in early diagnosis and in the follow up of optic nerve diseases.

Optic neuropathies: therapeutic approach.

The review deals with therapeutic aspects of optic nerve diseases. Attention is given to the lack of established guidelines for treatment of different optic neuropathies. In fact, there are no sure protocols in the literature for infective, inflammatory and vascular disorders. The authors present some new drugs and discuss the efficacy of related therapy, in particular for vascular disorders. The differentiated therapy for arteritic and non-arteritic AION is discussed. Treatment of vascular occlusion in the acute phase, in the post-occlusive state and prophylaxis is reported. The usefulness of anticoagulants is examined. In the conclusion, the authors stress the necessity to carry out properly controlled multicenter trials to obtain valid knowledge that allows rational and effective therapy protocols.

Antibiotic levels in aqueous and vitreous humor after intraocular administration.

Antibiotics poorly penetrate the vitreous humor after periocular or systemic administration. Sometimes a direct intravitreal injection is necessary for the treatment of bacterial endophthalmitis. The kinetics of the intravitreally injected antibiotics, netilmicin (500 micrograms/0.1 ml), piperacillin (2,000 micrograms/0.1 ml), ampicillin (2,000 micrograms/0.1 ml) and aztreonam (2,000 micrograms/0.1 ml), were examined in rabbits. Aqueous and vitreous antibiotic concentrations were assayed by microbiological methods. The results show that active levels of all drugs studied are present in the vitreous body for 48 h. In aqueous humor beta-lactam antibiotics are present in very small concentrations, whereas the aminoglycoside netilmicin (vitreous/aqueous ratio) have higher levels (%) than other drugs.

Aging and drug-induced optic nerve side effects.

In this review the authors attempt to explain how aging can determine optic nerve neuropathy and modify the pharmacodynamics and pharmacokinetics of a drug. The major causes of increased drug toxicity in the elderly are discussed. The most frequently used drugs that can cause optic nerve side effects are reported. The authors stress problems related to drug administration in the elderly and push towards the study of this aspect of geriatric ophthalmology.

Aqueous prostaglandin E2 and intraocular pressure after argon laser trabeculoplasty in glaucoma patients pretreated with topical piroxicam.

Intracameral injection of prostaglandin E2 causes an increase in intraocular pressure (IOP) in rabbits, cats, and monkeys. Arachidonic acid administered topically in rabbits and monkeys also increases IOP. The effect of prostaglandin E2 on IOP in human eyes is unclear. We performed paracentesis of the anterior chamber one hour after 180 degrees argon laser trabeculoplasty in cases of primary open-angle glaucoma. This laser treatment may increase IOP, but no correlation was found between post-operative IOP changes and PGE2 levels. PGE2 was significantly lower in ten eyes pretreated with topical piroxicam, a prostaglandin biosynthesis inhibitor (7 +/- 6 pg/ml), than in ten untreated eyes (443 +/- 232 pg/ml) and five controls. No significant difference was found between post-operative IOP in eyes pretreated and untreated with piroxicam. The low levels of PGE2 in the aqueous humour of eyes pretreated with piroxicam indirectly demonstrated the transcorneal penetration of the topically-administered drug, and the effectiveness of piroxicam in inhibiting the ocular synthesis of PGE2.

[Correlations between splenoportographic findings and risk of digestive hemorrhage in portal hypertension]. / Correlazioni fra reperti splenoportografici e rischio d'emorragie digestive nell'ipertensione portale.

In 102 cases examined by splenoportography (93 cirrhosis with patent splenoportal axis and 9 splenoportal thrombosis without appreciable liver changes), the occurrence of episodes of digestive haemorrhage was statistically correlated with age, sex, type of portal impediment, type of collateral circulation, and the presence or otherwise of ascites, and with portal pressure values measured by splenomanometry. The only statistically significant correlation was that concerning the type of hepatofugal collateral circulation, as digestive haemorrhage proved gradually less frequent in patients with gastro-oesophageal collateral circulation, in those with so-called infraportal collateral circulation and, finally, in those where angiography was unable to demonstrate the presence of any collateral circulation at all.