Synergy and Group Size in Microbial Cooperation

Microbes produce many molecules that are important for their growth and development, and the consumption of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Though the production of these public goods molecules has been studied intensely, little is known of how the benefits accrued and costs incurred depend on the quantity of public good molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density with a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether or not and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an “evolutionary trap” which can stymie the establishment and maintenance of cooperation. By allowing density dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results for experimental design

Histological evaluation of microfilled and conventional composite resins on monkey dental pulps

The pulpal responses to two micro-filled composite resins and a conventional composite resin were investigated in adult rhesus monkey teeth. All materials were randomly placed in unetched and unlined class V buccal cavity preparations. A total of 90 teeth were used in the study. Each material was evaluated at 3 days, 5 weeks and 8 weeks. Following perfusion, the teeth were prepared using routine histological procedures. The results indicated that the pulpal response to the microfilled and conventional composite resins were similar for all time periods, characterized by an initial slight to moderate response at 3 days, followed at 5 and 8 weeks by a zero to slight response with evidence of reparative dentine formation. Brown and Brenn staining for bacteria indicated positive staining reactions along the cavity wails of all teeth for all materials at each time period.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73366/1/j.1365-2591.1985.tb00453.x.pd

Effects of Composite Restorations on the Periodontal Membrane in Monkeys

We evaluated the histopathological response of the periodontal membrane to intentionolly-replanted teeth carrying composite (experimental) and silver amalgam (control) restorations in the middle third of each root. The study revealed that the amalgam produced, in the periodontal tissues, an initial localized inflammation that subsided with the subsequent formation of a fibrous capsule. However, the periodontal membrane adjacent to the composite resin restorations demonstrated chronic inflammation. It was concluded that the composite evoked chronic inflammatory responses of the periodontal tissues in monkeys.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67994/2/10.1177_00220345830620011801.pd

Experiences in running a complex electronic data capture system using mobile phones in a large-scale population trial in southern Nepal.

The increasing availability and capabilities of mobile phones make them a feasible means of data collection. Electronic Data Capture (EDC) systems have been used widely for public health monitoring and surveillance activities, but documentation of their use in complicated research studies requiring multiple systems is limited. This paper shares our experiences of designing and implementing a complex multi-component EDC system for a community-based four-armed cluster-Randomised Controlled Trial in the rural plains of Nepal, to help other researchers planning to use EDC for complex studies in low-income settings. We designed and implemented three interrelated mobile phone data collection systems to enrol and follow-up pregnant women (trial participants), and to support the implementation of trial interventions (women's groups, food and cash transfers). 720 field staff used basic phones to send simple coded text messages, 539 women's group facilitators used Android smartphones with Open Data Kit Collect, and 112 Interviewers, Coordinators and Supervisors used smartphones with CommCare. Barcoded photo ID cards encoded with participant information were generated for each enrolled woman. Automated systems were developed to download, recode and merge data for nearly real-time access by researchers. The systems were successfully rolled out and used by 1371 staff. A total of 25,089 pregnant women were enrolled, and 17,839 follow-up forms completed. Women's group facilitators recorded 5717 women's groups and the distribution of 14,647 food and 13,482 cash transfers. Using EDC sped up data collection and processing, although time needed for programming and set-up delayed the study inception. EDC using three interlinked mobile data management systems (FrontlineSMS, ODK and CommCare) was a feasible and effective method of data capture in a complex large-scale trial in the plains of Nepal. Despite challenges including prolonged set-up times, the systems met multiple data collection needs for users with varying levels of literacy and experience

Climate change adaptation in European river basins

This paper contains an assessment and standardized comparative analysis of the current water management regimes in four case-studies in three European river basins: the Hungarian part of the Upper Tisza, the Ukrainian part of the Upper Tisza (also called Zacarpathian Tisza), Alentejo Region (including the Alqueva Reservoir) in the Lower Guadiana in Portugal, and Rivierenland in the Netherlands. The analysis comprises several regime elements considered to be important in adaptive and integrated water management: agency, awareness raising and education, type of governance and cooperation structures, information management and—exchange, policy development and—implementation, risk management, and finances and cost recovery. This comparative analysis has an explorative character intended to identify general patterns in adaptive and integrated water management and to determine its role in coping with the impacts of climate change on floods and droughts. The results show that there is a strong interdependence of the elements within a water management regime, and as such this interdependence is a stabilizing factor in current management regimes. For example, this research provides evidence that a lack of joint/participative knowledge is an important obstacle for cooperation, or vice versa. We argue that there is a two-way relationship between information management and collaboration. Moreover, this research suggests that bottom-up governance is not a straightforward solution to water management problems in large-scale, complex, multiple-use systems, such as river basins. Instead, all the regimes being analyzed are in a process of finding a balance between bottom-up and top–down governance. Finally, this research shows that in a basin where one type of extreme is dominant—like droughts in the Alentejo (Portugal) and floods in Rivierenland (Netherlands)—the potential impacts of other extremes are somehow ignored or not perceived with the urgency they might deserv

Conditional ablation of macrophages disrupts ovarian vasculature

Macrophages are the most abundant immune cell within the ovary. Their dynamic distribution throughout the ovarian cycle and heterogenic array of functions suggest the involvement in various ovarian processes, but their functional role has yet to be fully established. The aim was to induce conditional macrophage ablation to elucidate the putative role of macrophages in maintaining the integrity of ovarian vasculature. Using the CD11b-diphtheria toxin receptor (DTR) mouse, in which expression of human DTR is under the control of the macrophage-specific promoter sequence CD11b, ovarian macrophages were specifically ablated in adult females by injections of diphtheria toxin (DT). CD11b-DTR mice were given DT treatment or vehicle and ovaries collected at 2, 8, 16, 24 and 48 h. Histochemical stains were employed to characterise morphological changes, immunohistochemistry for F4/80 to identify macrophages and the endothelial cell marker CD31 used to quantify vascular changes. In normal ovaries, macrophages were detected in corpora lutea and in the theca layer of healthy and atretic follicles. As macrophage ablation progressed, increasing amounts of ovarian haemorrhage were observed affecting both luteal and thecal tissue associated with significant endothelial cell depletion, increased erythrocyte accumulation and increased follicular atresia by 16 h. These events were followed by necrosis and profound structural damage. Changes were limited to the ovary, as DT treatment does not disrupt the vasculature of other tissues likely reflecting the unique cyclical nature of the ovarian vasculature and heterogeneity between macrophages within different tissues. These results show that macrophages play a critical role in maintaining ovarian vascular integrity

Protocol of the Low Birth Weight South Asia Trial (LBWSAT), a cluster-randomised controlled trial testing impact on birth weight and infant nutrition of Participatory Learning and Action through women's groups, with and without unconditional transfers of fortified food or cash during pregnancy in Nepal

BACKGROUND: Low birth weight (LBW, < 2500 g) affects one third of newborn infants in rural south Asia and compromises child survival, infant growth, educational performance and economic prospects. We aimed to assess the impact on birth weight and weight-for-age Z-score in children aged 0–16 months of a nutrition Participatory Learning and Action behaviour change strategy (PLA) for pregnant women through women’s groups, with or without unconditional transfers of food or cash to pregnant women in two districts of southern Nepal. METHODS: The study is a cluster randomised controlled trial (non-blinded). PLA comprises women’s groups that discuss, and form strategies about, nutrition in pregnancy, low birth weight and hygiene. Women receive up to 7 monthly transfers per pregnancy: cash is NPR 750 (~US$7) and food is 10 kg of fortified sweetened wheat-soya Super Cereal per month. The unit of randomisation is a rural village development committee (VDC) cluster (population 4000–9200, mean 6150) in southern Dhanusha or Mahottari districts. 80 VDCs are randomised to four arms using a participatory ‘tombola’ method. Twenty clusters each receive: PLA; PLA plus food; PLA plus cash; and standard care (control). Participants are (mostly Maithili-speaking) pregnant women identified from 8 weeks’ gestation onwards, and their infants (target sample size 8880 birth weights). After pregnancy verification, mothers may be followed up in early and late pregnancy, within 72 h, after 42 days and within 22 months of birth. Outcomes pertain to the individual level. Primary outcomes include birth weight within 72 h of birth and infant weight-for-age Z-score measured cross-sectionally on children born of the study. Secondary outcomes include prevalence of LBW, eating behaviour and weight during pregnancy, maternal and newborn illness, preterm delivery, miscarriage, stillbirth or neonatal mortality, infant Z-scores for length-for-age and weight-for-length, head circumference, and postnatal maternal BMI and mid-upper arm circumference. Exposure to women’s groups, food or cash transfers, home visits, and group interventions are measured. DISCUSSION: Determining the relative importance to birth weight and early childhood nutrition of adding food or cash transfers to PLA women’s groups will inform design of nutrition interventions in pregnancy. TRIAL REGISTRATION: ISRCTN75964374, 12 Jul 201

Rapid Accumulation of Polymorphonuclear Neutrophils in the Corpus luteum during Prostaglandin F2α-Induced Luteolysis in the Cow

Prostaglandin F2α (PGF2α) induces luteolysis within a few days in cows, and immune cells increase in number in the regressing corpus luteum (CL), implying that luteolysis is an inflammatory-like immune response. We investigated the rapid change in polymorphonuclear neutrophil (PMN) numbers in response to PGF2α administration as the first cells recruited to inflammatory sites, together with mRNA of interleukin-8 (IL-8: neutrophil chemoattractant) and P-selectin (leukocyte adhesion molecule) in the bovine CL. CLs were collected by ovariectomy at various times after PGF2α injection. The number of PMNs was increased at 5 min after PGF2α administration, whereas IL-8 and P-selectin mRNA increased at 30 min and 2 h, respectively. PGF2α directly stimulated P-selectin protein expression at 5–30 min in luteal endothelial cells (LECs). Moreover, PGF2α enhanced PMN adhesion to LECs, and this enhancement by PGF2α was inhibited by anti-P-selectin antibody, suggesting that P-selectin expression by PGF2α is crucial in PMN migration. In conclusion, PGF2α rapidly induces the accumulation of PMNs into the bovine CL at 5 min and enhances PMN adhesion via P-selectin expression in LECs. It is suggested that luteolytic cascade by PGF2α may involve an acute inflammatory-like response due to rapidly infiltrated PMNs

Protocol of the Low Birth Weight South Asia Trial (LBWSAT), a cluster-randomised controlled trial testing impact on birth weight and infant nutrition of Participatory Learning and Action through women's groups, with and without unconditional transfers of fortified food or cash during pregnancy in Nepal.

BACKGROUND: Low birth weight (LBW, < 2500 g) affects one third of newborn infants in rural south Asia and compromises child survival, infant growth, educational performance and economic prospects. We aimed to assess the impact on birth weight and weight-for-age Z-score in children aged 0-16 months of a nutrition Participatory Learning and Action behaviour change strategy (PLA) for pregnant women through women's groups, with or without unconditional transfers of food or cash to pregnant women in two districts of southern Nepal. METHODS: The study is a cluster randomised controlled trial (non-blinded). PLA comprises women's groups that discuss, and form strategies about, nutrition in pregnancy, low birth weight and hygiene. Women receive up to 7 monthly transfers per pregnancy: cash is NPR 750 (~US$7) and food is 10 kg of fortified sweetened wheat-soya Super Cereal per month. The unit of randomisation is a rural village development committee (VDC) cluster (population 4000-9200, mean 6150) in southern Dhanusha or Mahottari districts. 80 VDCs are randomised to four arms using a participatory 'tombola' method. Twenty clusters each receive: PLA; PLA plus food; PLA plus cash; and standard care (control). Participants are (mostly Maithili-speaking) pregnant women identified from 8 weeks' gestation onwards, and their infants (target sample size 8880 birth weights). After pregnancy verification, mothers may be followed up in early and late pregnancy, within 72 h, after 42 days and within 22 months of birth. Outcomes pertain to the individual level. Primary outcomes include birth weight within 72 h of birth and infant weight-for-age Z-score measured cross-sectionally on children born of the study. Secondary outcomes include prevalence of LBW, eating behaviour and weight during pregnancy, maternal and newborn illness, preterm delivery, miscarriage, stillbirth or neonatal mortality, infant Z-scores for length-for-age and weight-for-length, head circumference, and postnatal maternal BMI and mid-upper arm circumference. Exposure to women's groups, food or cash transfers, home visits, and group interventions are measured. DISCUSSION: Determining the relative importance to birth weight and early childhood nutrition of adding food or cash transfers to PLA women's groups will inform design of nutrition interventions in pregnancy. TRIAL REGISTRATION: ISRCTN75964374 , 12 Jul 2013