104 research outputs found

    Will dairy cattle production in West Africa be challenged by heat stress in the future?

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    This study focuses on heat stress conditions for dairy cattle production in West Africa under current and future climatic conditions. After testing the accuracy of the dynamically downscaled climate datasets for simulating the historical daily maximum temperature (Tmax) and relative humidity (RH) in West Africa for 50 meteorological stations, we used the dataset for calculating the temperature-humidity index (THI), i.e., an index indicating heat stress for dairy cattle on a daily scale. Calculations were made for the historical period (1981–2010) using the ERA-Interim reanalysis dataset, and for two future periods (2021–2050 and 2071–2100) using climate predictions of the GFDLESM2M, HadGEM2-ES, and MPI-ESM-MR Global Circulation Models (GCMs) under the RCP4.5 emission scenario. Here, we show that during the period from 1981 to 2010 for > 1/5 of the region of West Africa, the frequency of severe/danger heat events per year, i.e., events that result in significant decreases in productive and reproductive performances, increased from 11 to 29–38 days (significant at 95% confidence level). Most obvious changes were observed for the eastern and southeastern parts. Under future climate conditions periods with severe/danger heat stress events will increase further as compared with the historical period by 5–22% depending on the GCM used. Moreover, the average length of periods with severe/danger heat stress is expected to increase from ~ 3 days in the historical period to ~ 4–7 days by 2021–2050 and even to up to 10 days by 2071–2100. Based on the average results of three GCMs, by 2071–2100, around 22% of dairy cattle population currently living in this area is expected to experience around 70 days more of severe/danger heat stress (compare with the historical period), especially in the southern half of West Africa. The result is alarming, as it shows that dairy production systems in West Africa are jeopardized at large scale by climate change and that depending on the GCMused, milk production might decrease by 200–400 kg/year by 2071–2100 in around 1, 7, or 11%. Our study calls for the development of improved dairy cattle production systems with higher adaptive capacity in order to deal with expected future heat stress conditions

    Heat Stress Assessment for Dairy Cattle and Pig in Uganda

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    A shift from cattle to camel and goat farming can sustain milk production with lower inputs and emissions in north sub-Saharan Africa’s drylands

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    Climate change is increasingly putting milk production from cattle-based dairy systems in north sub-Saharan Africa (NSSA) under stress, threatening livelihoods and food security. Here we combine livestock heat stress frequency, dry matter feed production and water accessibility data to understand where environmental changes in NSSA’s drylands are jeopardizing cattle milk production. We show that environmental conditions worsened for ∌17% of the study area. Increasing goat and camel populations by ∌14% (∌7.7 million) and ∌10% (∌1.2 million), respectively, while reducing the dairy cattle population by ∌24% (∌5.9 million), could result in ∌0.14 Mt (+5.7%) higher milk production, lower water (−1,683.6 million m3, −15.3%) and feed resource (−404.3 Mt, −11.2%) demand—and lower dairy emissions by ∌1,224.6 MtCO2e (−7.9%). Shifting herd composition from cattle towards the inclusion of, or replacement with, goats and camels can secure milk production and support NSSA’s dairy production resilience against climate change

    Mycorrhiza-mediated recruitment of complete denitrifying Pseudomonas reduces N₂O emissions from soil

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    Background Arbuscular mycorrhizal fungi (AMF) are key soil organisms and their extensive hyphae create a unique hyphosphere associated with microbes actively involved in N cycling. However, the underlying mechanisms how AMF and hyphae-associated microbes may cooperate to influence N2O emissions from “hot spot” residue patches remain unclear. Here we explored the key microbes in the hyphosphere involved in N2O production and consumption using amplicon and shotgun metagenomic sequencing. Chemotaxis, growth and N2O emissions of isolated N2O-reducing bacteria in response to hyphal exudates were tested using in vitro cultures and inoculation experiments. Results AMF hyphae reduced denitrification-derived N2O emission (max. 63%) in C- and N-rich residue patches. AMF consistently enhanced the abundance and expression of clade I nosZ gene, and inconsistently increased that of nirS and nirK genes. The reduction of N2O emissions in the hyphosphere was linked to N2O-reducing Pseudomonas specifically enriched by AMF, concurring with the increase in the relative abundance of the key genes involved in bacterial citrate cycle. Phenotypic characterization of the isolated complete denitrifying P. fluorescens strain JL1 (possessing clade I nosZ) indicated that the decline of net N2O emission was a result of upregulated nosZ expression in P. fluorescens following hyphal exudation (e.g. carboxylates). These findings were further validated by re-inoculating sterilized residue patches with P. fluorescens and by an 11-year-long field experiment showing significant positive correlation between hyphal length density with the abundance of clade I nosZ gene. Conclusions The cooperation between AMF and the N2O-reducing Pseudomonas residing on hyphae significantly reduce N2O emissions in the microsites. Carboxylates exuded by hyphae act as attractants in recruiting P. fluorescens and also as stimulants triggering nosZ gene expression. Our discovery indicates that reinforcing synergies between AMF and hyphosphere microbiome may provide unexplored opportunities to stimulate N2O consumption in nutrient-enriched microsites, and consequently reduce N2O emissions from soils. This knowledge opens novel avenues to exploit cross-kingdom microbial interactions for sustainable agriculture and for climate change mitigation

    Recognizing Speech in a Novel Accent: The Motor Theory of Speech Perception Reframed

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    The motor theory of speech perception holds that we perceive the speech of another in terms of a motor representation of that speech. However, when we have learned to recognize a foreign accent, it seems plausible that recognition of a word rarely involves reconstruction of the speech gestures of the speaker rather than the listener. To better assess the motor theory and this observation, we proceed in three stages. Part 1 places the motor theory of speech perception in a larger framework based on our earlier models of the adaptive formation of mirror neurons for grasping, and for viewing extensions of that mirror system as part of a larger system for neuro-linguistic processing, augmented by the present consideration of recognizing speech in a novel accent. Part 2 then offers a novel computational model of how a listener comes to understand the speech of someone speaking the listener's native language with a foreign accent. The core tenet of the model is that the listener uses hypotheses about the word the speaker is currently uttering to update probabilities linking the sound produced by the speaker to phonemes in the native language repertoire of the listener. This, on average, improves the recognition of later words. This model is neutral regarding the nature of the representations it uses (motor vs. auditory). It serve as a reference point for the discussion in Part 3, which proposes a dual-stream neuro-linguistic architecture to revisits claims for and against the motor theory of speech perception and the relevance of mirror neurons, and extracts some implications for the reframing of the motor theory

    Anti-cancer effects and mechanism of actions of aspirin analogues in the treatment of glioma cancer

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    INTRODUCTION: In the past 25 years only modest advancements in glioma treatment have been made, with patient prognosis and median survival time following diagnosis only increasing from 3 to 7 months. A substantial body of clinical and preclinical evidence has suggested a role for aspirin in the treatment of cancer with multiple mechanisms of action proposed including COX 2 inhibition, down regulation of EGFR expression, and NF-ÎșB signaling affecting Bcl-2 expression. However, with serious side effects such as stroke and gastrointestinal bleeding, aspirin analogues with improved potency and side effect profiles are being developed. METHOD: Effects on cell viability following 24 hr incubation of four aspirin derivatives (PN508, 517, 526 and 529) were compared to cisplatin, aspirin and di-aspirin in four glioma cell lines (U87 MG, SVG P12, GOS – 3, and 1321N1), using the PrestoBlue assay, establishing IC50 and examining the time course of drug effects. RESULTS: All compounds were found to decrease cell viability in a concentration and time dependant manner. Significantly, the analogue PN517 (IC50 2mM) showed approximately a twofold increase in potency when compared to aspirin (3.7mM) and cisplatin (4.3mM) in U87 cells, with similar increased potency in SVG P12 cells. Other analogues demonstrated similar potency to aspirin and cisplatin. CONCLUSION: These results support the further development and characterization of novel NSAID derivatives for the treatment of glioma

    Training and expertise in undertaking assisted vaginal delivery (AVD): a mixed methods systematic review of practitioners views and experiences

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    Abstract: Background: During childbirth, complications may arise which necessitate an expedited delivery of the fetus. One option is instrumental assistance (forceps or a vacuum-cup), which, if used with skill and sensitivity, can improve maternal/neonatal outcomes. This review aimed to understand the core competencies and expertise required for skilled use in AVD in conjunction with reviewing potential barriers and facilitators to gaining competency and expertise, from the point of view of maternity care practitioners, funders and policy makers. Methods: A mixed methods systematic review was undertaken in five databases. Inclusion criteria were primary studies reporting views, opinions, perspectives and experiences of the target group in relation to the expertise, training, behaviours and competencies required for optimal AVD, barriers and facilitators to achieving practitioner competencies, and to the implementation of appropriate training. Quality appraisal was carried out on included studies. A mixed-methods convergent synthesis was carried out, and the findings were subjected to GRADE-CERQual assessment of confidence. Results: 31 papers, reporting on 27 studies and published 1985–2020 were included. Studies included qualitative designs (3), mixed methods (3), and quantitative surveys (21). The majority (23) were from high-income countries, two from upper-middle income countries, one from a lower-income country: one survey included 111 low-middle countries. Confidence in the 10 statements of findings was mostly low, with one exception (moderate confidence). The review found that AVD competency comprises of inter-related skill sets including non-technical skills (e.g. behaviours), general clinical skills; and specific technical skills associated with particular instrument use. We found that practitioners needed and welcomed additional specific training, where a combination of teaching methods were used, to gain skills and confidence in this field. Clinical mentorship, and observing others confidently using the full range of instruments, was also required, and valued, to develop competency and expertise in AVD. However, concerns regarding poor outcomes and litigation were also raised. Conclusion: Access to specific AVD training, using a combination of teaching methods. Complements, but does not replace, close clinical mentorship from experts who are positive about AVD, and opportunities to practice emerging AVD skills with supportive supervision. Further research is required to ascertain effective modalities for wider training, education, and supportive supervision for optimal AVD use

    Women’s, partners’ and healthcare providers’ views and experiences of assisted vaginal birth: a systematic mixed methods review

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    Background When certain complications arise during the second stage of labour, assisted vaginal delivery (AVD), a vaginal birth with forceps or vacuum extractor, can effectively improve outcomes by ending prolonged labour or by ensuring rapid birth in response to maternal or fetal compromise. In recent decades, the use of AVD has decreased in many settings in favour of caesarean section (CS). This review aimed to improve understanding of experiences, barriers and facilitators for AVD use. Methods Systematic searches of eight databases using predefined search terms to identify studies reporting views and experiences of maternity service users, their partners, health care providers, policymakers, and funders in relation to AVD. Relevant studies were assessed for methodological quality. Qualitative findings were synthesised using a meta-ethnographic approach. Confidence in review findings was assessed using GRADE CERQual. Findings from quantitative studies were synthesised narratively and assessed using an adaptation of CERQual. Qualitative and quantitative review findings were triangulated using a convergence coding matrix. Results Forty-two studies (published 1985–2019) were included: six qualitative, one mixed-method and 35 quantitative. Thirty-five were from high-income countries, and seven from LMIC settings. Confidence in the findings was moderate or low. Spontaneous vaginal birth was most likely to be associated with positive short and long-term outcomes, and emergency CS least likely. Views and experiences of AVD tended to fall somewhere between these two extremes. Where indicated, AVD can be an effective, acceptable alternative to caesarean section. There was agreement or partial agreement across qualitative studies and surveys that the experience of AVD is impacted by the unexpected nature of events and, particularly in high-income settings, unmet expectations. Positive relationships, good communication, involvement in decision-making, and (believing in) the reason for intervention were important mediators of birth experience. Professional attitudes and skills (development) were simultaneously barriers and facilitators of AVD in quantitative studies. Conclusions Information, positive interaction and communication with providers and respectful care are facilitators for acceptance of AVD. Barriers include lack of training and skills for decision-making and use of instruments
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