title: Monoids with tests and the algebra of possibly non-halting programs

authors: Jackson, Marcel

subjects: Science & Technology

abstract: We study the algebraic theory of computable functions, which can be viewed as arising from possibly non-halting computer programs or algorithms, acting on some state space, equipped with operations of composition, if-then-else and while-do defined in terms of a Boolean algebra of conditions. It has previously been shown that there is no finite axiomatisation of algebras of partial functions under these operations alone, and this holds even if one restricts attention to transformations (representing halting programs) rather than partial functions, and omits while-do from the signature. In the halting case, there is a natural “fix”, which is to allow composition of halting programs with conditions, and then the resulting algebras admit a finite axiomatisation. In the current setting such compositions are not possible, but by extending the notion of if-then-else, we are able to give finite axiomatisations of the resulting algebras of (partial) functions, with while-do in the signature if the state space is assumed finite. The axiomatisations are extended to consider the partial predicate of equality. All algebras considered turn out to be enrichments of the notion of a (one-sided) restriction semigroup

text: Monoids with tests and the algebra of possibly non-halting programs We study the algebraic theory of computable functions, which can be viewed as arising from possibly non-halting computer programs or algorithms, acting on some state space, equipped with operations of composition, if-then-else and while-do defined in terms of a Boolean algebra of conditions. It has previously been shown that there is no finite axiomatisation of algebras of partial functions under these operations alone, and this holds even if one restricts attention to transformations (representing halting programs) rather than partial functions, and omits while-do from the signature. In the halting case, there is a natural “fix”, which is to allow composition of halting programs with conditions, and then the resulting algebras admit a finite axiomatisation. In the current setting such compositions are not possible, but by extending the notion of if-then-else, we are able to give finite axiomatisations of the resulting algebras of (partial) functions, with while-do in the signature if the state space is assumed finite. The axiomatisations are extended to consider the partial predicate of equality. All algebras considered turn out to be enrichments of the notion of a (one-sided) restriction semigroup

year: 2015-03

title: Effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi (Basilewsky)

authors: Li, Wei

subjects: foraging success

abstract: This study aimed to evaluate the effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi. Predation on crucian carp Carassius auratus by juvenile mandarin fish was tested at five levels of turbidity combined with two light intensities, imitating daylight and night in two turbidity types. Foraging success was significantly lower in clay-induced turbidity than in algal-induced turbidity. In clay-induced turbidity trials, there was a slight but insignificant increase in foraging success of mandarin fish with increasing turbidity under lighted conditions. In algal-induced turbidity trials, there were no significant differences in foraging success of mandarin fish among turbidity levels at both light and dark levels, but at 80 NTU turbidity level, foraging success was lower than in all the other turbidity levels. There was no significant difference in foraging success at different turbidities under darkness. These results suggest that piscivory of mandarin fish is influenced by different turbidity types but is not significantly influenced by increased turbidity combined with decreased light intensity.

text: Effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi (Basilewsky) This study aimed to evaluate the effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi. Predation on crucian carp Carassius auratus by juvenile mandarin fish was tested at five levels of turbidity combined with two light intensities, imitating daylight and night in two turbidity types. Foraging success was significantly lower in clay-induced turbidity than in algal-induced turbidity. In clay-induced turbidity trials, there was a slight but insignificant increase in foraging success of mandarin fish with increasing turbidity under lighted conditions. In algal-induced turbidity trials, there were no significant differences in foraging success of mandarin fish among turbidity levels at both light and dark levels, but at 80 NTU turbidity level, foraging success was lower than in all the other turbidity levels. There was no significant difference in foraging success at different turbidities under darkness. These results suggest that piscivory of mandarin fish is influenced by different turbidity types but is not significantly influenced by increased turbidity combined with decreased light intensity.

year: 2013

title: Exploring patient experiences and power dynamics in an acute general surgical ward: A mixed methods study exploring patient and staff
perceptions of the inpatient experience at Waikato Hospital

authors: Drake, Emma Rose

subjects: Nursing

abstract: Background: Alongside health outcomes, patient experiences are considered crucial in identifying the quality of a health care setting. General surgery comprise the largest range of pathologies and accounts for the highest number of patient discharges of any surgical specialty. As a way to address the power imbalance between healthcare staff and patients, patient-centred models of care are increasingly being adopted and implemented within hospitals including surgery. This study aims to investigate the current experiences of acutely admitted patients in a general surgical ward at Waikato Hospital, including opportunities for and challenges to improvement initiatives. Furthermore, the study examines relevant staff members perspectives of the inpatient experience and seeks to determine the efficacy of a proposed intervention focusing on empowering patients and their families.
Methods: The study was a mixed method design involving two phases. Phase I obtained qualitative data from semi-structured interviews with six patients and twelve staff members. Themes which emerged from the qualitative data in phase I were used to inform the development of phase II, as well as to inform a proposed patient self- assessment intervention. Phase II obtained quantitative data through Likert scale response surveys provided to acute patients on, or near to, their day of discharge from the surgical ward over a two month period.
Results: A total of six patients and 12 healthcare staff (senior registered nurses, n=3; surgical registered nurse managers, n=2; surgical fellows, n=2; surgical registrar, n=1; dietitian, n=1; social worker, n=1; occupational therapist, n=1; and physiotherapist n=1) were involved in phase I. A total of 53 surveys were returned from patients in Phase II (63.1% response rate). Qualitative data from phase I was analysed using a general inductive approach. This revealed three themes including power and control concerns for patients, the hierarchy of the health care team and the surrounding stressors of the organisation and environment. Analysis of the quantitative data collected descriptive statistics and calculated chi-squares. Of note were the statistically significant differences particularly between patients of Māori ethnicity comparatively to non-Māori, and according to gender and reason in hospital. There were no statistically significant differences for patients according to age group.
Conclusion: This study identified both the experiences of patients and staff in an acute general surgical context. The study found that the proposed patient self- assessment intervention was not immediately recommended. This was due to the current recommendations from patients who identified their strong preference was for face-to-face communication with staff. It was also due to staff members identification of a perceived inability to consistently provide person-centred care which corresponded with the patient self-assessment data. Acute general surgical care needs of patients were perceived by staff as taking precedent and current workplace stressors, including staffing and skill mix deficits and perceived lack of staff wellbeing supports, were strong inhibitors for staff to provide their preferred capacity of patient-centred care.

text: Exploring patient experiences and power dynamics in an acute general surgical ward: A mixed methods study exploring patient and staff
perceptions of the inpatient experience at Waikato Hospital Background: Alongside health outcomes, patient experiences are considered crucial in identifying the quality of a health care setting. General surgery comprise the largest range of pathologies and accounts for the highest number of patient discharges of any surgical specialty. As a way to address the power imbalance between healthcare staff and patients, patient-centred models of care are increasingly being adopted and implemented within hospitals including surgery. This study aims to investigate the current experiences of acutely admitted patients in a general surgical ward at Waikato Hospital, including opportunities for and challenges to improvement initiatives. Furthermore, the study examines relevant staff members perspectives of the inpatient experience and seeks to determine the efficacy of a proposed intervention focusing on empowering patients and their families.
Methods: The study was a mixed method design involving two phases. Phase I obtained qualitative data from semi-structured interviews with six patients and twelve staff members. Themes which emerged from the qualitative data in phase I were used to inform the development of phase II, as well as to inform a proposed patient self- assessment intervention. Phase II obtained quantitative data through Likert scale response surveys provided to acute patients on, or near to, their day of discharge from the surgical ward over a two month period.
Results: A total of six patients and 12 healthcare staff (senior registered nurses, n=3; surgical registered nurse managers, n=2; surgical fellows, n=2; surgical registrar, n=1; dietitian, n=1; social worker, n=1; occupational therapist, n=1; and physiotherapist n=1) were involved in phase I. A total of 53 surveys were returned from patients in Phase II (63.1% response rate). Qualitative data from phase I was analysed using a general inductive approach. This revealed three themes including power and control concerns for patients, the hierarchy of the health care team and the surrounding stressors of the organisation and environment. Analysis of the quantitative data collected descriptive statistics and calculated chi-squares. Of note were the statistically significant differences particularly between patients of Māori ethnicity comparatively to non-Māori, and according to gender and reason in hospital. There were no statistically significant differences for patients according to age group.
Conclusion: This study identified both the experiences of patients and staff in an acute general surgical context. The study found that the proposed patient self- assessment intervention was not immediately recommended. This was due to the current recommendations from patients who identified their strong preference was for face-to-face communication with staff. It was also due to staff members identification of a perceived inability to consistently provide person-centred care which corresponded with the patient self-assessment data. Acute general surgical care needs of patients were perceived by staff as taking precedent and current workplace stressors, including staffing and skill mix deficits and perceived lack of staff wellbeing supports, were strong inhibitors for staff to provide their preferred capacity of patient-centred care.

year: 2022