Emergent behaviour in a chlorophenol-mineralising three-tiered microbial `food web'

Anaerobic digestion enables the water industry to treat wastewater as a resource for generating energy and recovering valuable by-products. The complexity of the anaerobic digestion process has motivated the development of complex models. However, this complexity makes it intractable to pin-point stability and emergent behaviour. Here, the widely used Anaerobic Digestion Model No. 1 (ADM1) has been reduced to its very backbone, a syntrophic two-tiered microbial food chain and a slightly more complex three-tiered microbial food web, with their stability analysed as function of the inflowing substrate concentration and dilution rate. Parameterised for phenol and chlorophenol degradation, steady-states were always stable and non-oscillatory. Low input concentrations of chlorophenol were sufficient to maintain chlorophenol- and phenol-degrading populations but resulted in poor conversion and a hydrogen flux that was too low to sustain hydrogenotrophic methanogens. The addition of hydrogen and phenol boosted the populations of all three organisms, resulting in the counterintuitive phenomena that (i) the phenol degraders were stimulated by adding hydrogen, even though hydrogen inhibits phenol degradation, and (ii) the dechlorinators indirectly benefitted from measures that stimulated their hydrogenotrophic competitors; both phenomena hint at emergent behaviour.Comment: 19 pages, 8 figure

INN Placement Website

Work experience is a valuable experience for all students. It can be hard for students to find work experience and sometimes challenging for them to understand the job market. Students at Innovation North have an opportunity to undertake a Placement year between L5 and L6 and this is something we wish to actively promote, support and encourage. Innovation North had a website which held the details of the work opportunities, it was very dated, contained no images and was cumbersome to search. The project was to create a new website for Innovation North students holding details of all work placements (short, long term, voluntary, paid). Specification for the site included search facilities, providing information and giving reflections from students who had undertaken work opportunities. The website has been developed by three INN students. It has been live since September 2009

Generic Modal Cut Elimination Applied to Conditional Logics

We develop a general criterion for cut elimination in sequent calculi for propositional modal logics, which rests on absorption of cut, contraction, weakening and inversion by the purely modal part of the rule system. Our criterion applies also to a wide variety of logics outside the realm of normal modal logic. We give extensive example instantiations of our framework to various conditional logics. For these, we obtain fully internalised calculi which are substantially simpler than those known in the literature, along with leaner proofs of cut elimination and complexity. In one case, conditional logic with modus ponens and conditional excluded middle, cut elimination and complexity were explicitly stated as open in the literature

Opioids depress cortical centers responsible for the volitional control of respiration

Respiratory depression limits provision of safe opioid analgesia and is the main cause of death in drug addicts. Although opioids are known to inhibit brainstem respiratory activity, their effects on cortical areas that mediate respiration are less well understood. Here, functional magnetic resonance imaging was used to examine how brainstem and cortical activity related to a short breath hold is modulated by the opioid remifentanil. We hypothesized that remifentanil would differentially depress brain areas that mediate sensory-affective components of respiration over those that mediate volitional motor control. Quantitative measures of cerebral blood flow were used to control for hypercapnia-induced changes in blood oxygen level-dependent (BOLD) signal. Awareness of respiration, reflected by an urge-to-breathe score, was profoundly reduced with remifentanil. Urge to breathe was associated with activity in the bilateral insula, frontal operculum, and secondary somatosensory cortex. Localized remifentanil-induced decreases in breath hold-related activity were observed in the left anterior insula and operculum. We also observed remifentanil-induced decreases in the BOLD response to breath holding in the left dorsolateral prefrontal cortex, anterior cingulate, the cerebellum, and periaqueductal gray, brain areas that mediate task performance. Activity in areas mediating motor control (putamen, motor cortex) and sensory-motor integration (supramarginal gyrus) were unaffected by remifentanil. Breath hold-related activity was observed in the medulla. These findings highlight the importance of higher cortical centers in providing contextual awareness of respiration that leads to appropriate modulation of respiratory control. Opioids have profound effects on the cortical centers that control breathing, which potentiates their actions in the brainstem

On the origin of nonequivalent states: How we can talk about preprints

Increasingly, preprints are at the center of conversations across the research ecosystem. But disagreements remain about the role they play. Do they "count" for research assessment? Is it ok to post preprints in more than one place? In this paper, we argue that these discussions often conflate two separate issues, the history of the manuscript and the status granted it by different communities. In this paper, we propose a new model that distinguishes the characteristics of the object, its "state", from the subjective "standing" granted to it by different communities. This provides a way to discuss the difference in practices between communities, which will deliver more productive conversations and facilitate negotiation, as well as sharpening our focus on the role of different stakeholders on how to collectively improve the process of scholarly communications not only for preprints, but other forms of scholarly contributions

Intrapartum-related birth asphyxia in South Africa lessons From the first national perinatal care survey

Background. The recent amalgamation of data by users of the Perinatal Problem Identification Programme (PPIP) throughout South Africa has culminated in the publication of the Saving Babies report.Objectives. To determine the absolute rate of death from intrapartum-related birth asphyxia, and the contribution of intrapartum-related asphyxia to total perinatal mortality in South African hospitals, and to identify the primary obstetric causes and avoidable factors for these deaths.Methods. The amalgamated PPIP data for the year 2000 were obtained from 27 state hospitals (6 metropolitan, 12 town and 9 rural) in South Africa. In PPIP-based audit, all perinatal deaths are assigned primary obstetric causes and avoidable factors, and these elements were obtained for all deaths resulting from intrapartum-related birth asphyxia. Results. There were 123 508 births in the hospitals surveyed, with 4 142 perinatal deaths among infants ≥ 1 000 g, giving a perinatal mortality rate of 33.5/1 000 births. The perinatal mortality rate from intrapartum-related birth asphyxia was 4.8/1 000 births. The most frequent avoidable factors were delay by mothers in seeking attention during labour (36.6%), signs of fetal distress interpreted incorrectly (24.9%), inadequate fetal monitoring (18.0%) and no response to poor progress in labour (7.0%). The perinatal mortality rates for metropolitan, town and rural areas were 30.0, 39.4 and 30.9/1 000 births respectively. The contribution of intrapartum-related birth asphyxia to perinatal mortality in these areas was 10.8%, 16.7% and 26.4% respectively

The use of Doppler velocitnetry of the utnbilical artery before 24 weeks' gestation to screen for high-risk pregnancies

Objective. To describe the prevalence and natural history of absent end-diastolic velocities (AEDV) in the mnbilical artery of the fetus between 16 and 24 weeks' gestation, and to evaluate its role as a screening test.Design. Population-based descriptive study.Setting. Tygerberg Hospital, Tygerberg, South Africa. The hospital serves a population from the lower socio-economic bracket.Subjects. Doppler velocimetry was performed at routine ultrasound examinations for confirmation of gestational age in 496 women.Main outcome measures. The occurrence of perinatal death, small-for-gestational-age (SGA) babies and proteinuric hypertension.Results. Forty-four (8,9%) patients had AEDVs at the first examination, but AEDV persisted in only 1. In this case, severe proteinuric hypertension developed unexpectedly at 29 weeks' gestation and the fetus needed delivery because ofpersistent late decelerations of the fetal heart rate pattern. There was a significant association between the group with AEDV at first examination and the development of proteinuric hypertension (P <0,05), but no association with SGA babies. The association with proteinuric hypertension was too weak to be of clinical use.Conclusion. Doppler velocimetry of the mnbilical artery, performed along with routine ultrasound examination to confirm gestational age, is not of use as a screening test for identifYing highrisk pregnancies

The potential for preventing the delivery and perinatal mortality of lowbirth- weight babies in a black urban population

Objective. To determine the potentiaJ for preventing the delivery and perinatal  mortality of low-birth-weight (LBW) babies in a black urban population.Design. Cross-sectionaJ descriptive study.Setting. All women delivering babies weighing less than 2 500 g at Kalafong  Hospital in a 6-month period (December 1991 - May 1992).Main outcome measures. The primary obstetric reason for delivery; whether the  labour was of spontaneous onset or iatrogenic; whether labour was theoretically  preventable using currently accepted practice; the number of patients in whom suppression of delivery was attempted in the theoretically preventable group; and the perinatal mortality rate of that group.Results. There were 124 perinatal deaths (22.5%) in the 550 LBW babies delivered from 465 singleton pregnancies, 42 twin pregnancies and 1 triplet pregnancy. The  primary obstetric reasons for delivery were spontaneous preterm labour (28%), hypertensive diseases (19%), premature rupture of membranes (180/0),  spontaneous labour in lightfor-gestational-age babies (16%), unexplained intra-uterine deaths (8%), antepartum haemomhage (8%) and other causes (3%). A medical decision to terminate the pregnancy before labour was made in 177 (34.8%) cases, the major reason being hypertensive diseases (84 mothers;  47.5%). In the remaining 331 mothers with spontaneous onset of labour, labour was theoretically preventable in 63 (19%) and prevention was only attempted in 12 (2.4% of the total mothers). The major reason for not attempting to suppress labour in the others was that the patients arrived too late at the hospital for intervention to take place.Conclusion. Hospital staff can do little to prevent the delivery of LBW babies in a black urban population

Cooperative optimal preview tracking for linear descriptor multi-agent systems

© 2018 The Franklin Institute. In this paper, a cooperative optimal preview tracking problem is considered for continuous-time descriptor multi-agent systems with a directed topology containing a spanning tree. By the acyclic assumption and state augmentation technique, it is shown that the cooperative tracking problem is equivalent to local optimal regulation problems of a set of low-dimensional descriptor augmented subsystems. To design distributed optimal preview controllers, restricted system equivalent (r.s.e.) and preview control theory are first exploited to obtain optimal preview controllers for reduced-order normal subsystems. Then, by using the invertibility of restricted equivalent relations, a constructive method for designing distributed controller is presented which also yields an explicit admissible solution for the generalized algebraic Riccati equation. Sufficient conditions for achieving global cooperative preview tracking are proposed proving that the distributed controllers are able to stabilize the descriptor augmented subsystems asymptotically. Finally, the validity of the theoretical results is illustrated via numerical simulation

Evaluation of a strict protocol approach in managing women with severe disease due to hypertension in pregnancy: A before and after study

BACKGROUND: To evaluate whether the introduction of a strict protocol based on the systemic evaluation of critically ill pregnant women with complications of hypertension affected the outcome of those women. METHOD: Study group: Indigent South African women managed in the tertiary hospitals of the Pretoria Academic Complex. Since 1997 a standard definition of women with severe acute maternal morbidity (SAMM), also referred to as a Nearmiss, has been used in the Pretoria Academic Complex. All cases of SAMM and maternal deaths (MD) were entered on the Maternal Morbidity and Mortality Audit System programme (MaMMAS). A comparison of outcome of severely ill women who had complications of hypertension in pregnancy was performed between 1997–1998 (original protocol) and 2002–2003 (strict protocol). Data include women referred from outside the Pretoria Academic Complex area to the tertiary hospitals. RESULTS: Between 1997–1998 there were 79 women with SAMM and 18 maternal deaths due to complications of hypertension, compared with 91 women with SAMM and 13 maternal deaths in 2002–2003. The mortality index (MI) declined from 18.6% to 12.5% (OR 0.62, 95% CI 0.27–1.45). Statistically significant fewer women had renal failure (RR 0.37, 95% CI 0.21 – 0.66) and cerebral complications (RR 0.52, 95%CI 0.34 – 0.81) during the second period, and liver dysfunction (RR 0.27 95%CI 0.06 – 1.25) tended to be lower. However, there tended to be an increase in the number of women, who had immune system failure (RR 4.2 95%CI 0.93 – 18.94) and respiratory failure (RR 1.42 95%CI 0.88 – 2.29) although it did not reach significance. Cardiac failure remained constant (RR 0.84 95%CI 0.54 – 1.30). CONCLUSION: The strict protocol approach based on the systemic evaluation of severely ill pregnant women with complications of hypertension and an intensive, regular feedback mechanism has been associated with a reduction in the number of patients with renal failure and cerebral compromise