Substrate-induced pH changes and process stability of anaerobic digestion of shea waste

Shea butter extraction involves the generation of waste of environmental concern. To help find a solution to the management of this waste, and to search for an alternative source of energy, this study was carried out to investigate the potential of shea waste in generating methane gas through anaerobic digestion. At high concentrations, volatile fatty acids produce a low pH, which may inhibit hydrolysis, thereby affecting the stability of the anaerobic digestion process. The influence of pH changes on process stability (or otherwise) was also investigated. The study involved two fermentation processes: mono-fermentation and co-fermentation involving a mix of shea waste and cattle dung. The mono-fermentation investigations comprised six treatments - three organic dry matter concentrations of 7%, 5% and 3%, combined with two hydraulic retention times of 30 and 60 days. The co-fermentation investigations comprised three treatments of shea waste and cattle manure mix in proportions (by volume) of 50:50, 75:25 and 90:10. The results showed that changes in pH were a good parameter for indicating process instability. The results also showed that monofermentation of shea waste was not a viable option in anaerobic digestion for biogas production, whilst only the substrate with 50% cattle manure in the co-fermentation trials showed process stability, producing biogas with adequate methane content

Backward particle message passing

Particle methods are an established way to represent messages and perform message passing in factor graphs. Despite their common use, there are several cases for which messages are hard to compute, even in linear models. Building on results from Gaussian message passing, we demonstrate how backward particle-based messages can be computed and describe a practical application in the context of fiber-optical communications

Uncertainty measures and business cycles : evidence from the US

Most of the macro-literature on uncertainty has focused on macro-uncertainty caused by real activity as a source of economic fluctuations. Economic uncertainty reduces total demand in the economy via a conventional channel that is associated with real option theory. Given the findings of the existing literature, financial uncertainty other than macroeconomic uncertainty matters more for business cycle fluctuations. This study seeks to answer the following questions: Is uncertainty the primary cause of the business cycle’s fluctuations? Alternatively, does it matter what kind of uncertainty exists? The research utilized the generalized linear model (GLM) and the Bayesian generalized linear model (BGLM) to analyze a dataset covering the time from July 1960 to April 2015 in the United States. Elevated levels of macroeconomic uncertainty, akin to real uncertainty, and economic policy uncertainty, as measured by news sources, demonstrate a counter-cyclical pattern in relation to business cycles. Low levels of uncertainty have a positive impact on business cycles, leading to an increase in industrial production. Conversely, high levels of uncertainty have a negative effect on business cycles, causing a decline in industrial output. We are of the opinion that high levels of macroeconomic uncertainty have a ripple effect on the entire economy, which may stifle investments, reduce consumption, and create unemployment, which is likely to influence labor participation

Substrate-Induced pH Changes and Process Stability of Anaerobic Digestion of Shea Waste

Shea butter extraction involves the generation of waste of environmental concern. To help find a solution to the management of this waste, and to search for an alternative source of energy, this study was carried out to investigate the potential of shea waste in generating methane gas through anaerobic digestion. At high concentrations, volatile fatty acids produce a low pH, which may inhibit hydrolysis, thereby affecting the stability of the anaerobic digestion process. The influence of pH changes on process stability (or otherwise) was also investigated. The study involved two fermentation processes: mono-fermentation and co-fermentation involving a mix of shea waste and cattle dung. The mono-fermentation investigations comprised six treatments - three organic dry matter concentrations of 7%, 5% and 3%, combined with two hydraulic retention times of 30 and 60 days. The co-fermentation investigations comprised three treatments of shea waste and cattle manure mix in proportions (by volume) of 50:50, 75:25 and 90:10. The results showed that changes in pH were a good parameter for indicating process instability. The results also showed that monofermentation of shea waste was not a viable option in anaerobic digestion for biogas production, whilst only the substrate with 50% cattle manure in the co-fermentation trials showed process stability, producing biogas with adequate methane content

Kerr nonlinearity mitigation in 5 × 28-GBd PDM 16-QAM signal transmission over a dispersion-uncompensated link with backward-pumped distributed Raman amplification

International audienceWe present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectral inversion of 5 × 28-GBd polarization-multiplexed 16-QAM signals. Signal quality factor (Q-factor) improvements of 1.1 dB and 0.8 dB were obtained in the cases of a single-channel and a five-channel wavelength-division multiplexing (WDM) system, respectively. The experimental results are compared to numerical simulations with good agreement. It is also shown with simulations that a maximum transmission reach of 2400 km enabled by the optical phase conjugator is possible for the WDM signal

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015.

BACKGROUND: Healthy life expectancy (HALE) and disability-adjusted life-years (DALYs) provide summary measures of health across geographies and time that can inform assessments of epidemiological patterns and health system performance, help to prioritise investments in research and development, and monitor progress toward the Sustainable Development Goals (SDGs). We aimed to provide updated HALE and DALYs for geographies worldwide and evaluate how disease burden changes with development. METHODS: We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2015. We calculated DALYs by summing years of life lost (YLLs) and years of life lived with disability (YLDs) for each geography, age group, sex, and year. We estimated HALE using the Sullivan method, which draws from age-specific death rates and YLDs per capita. We then assessed how observed levels of DALYs and HALE differed from expected trends calculated with the Socio-demographic Index (SDI), a composite indicator constructed from measures of income per capita, average years of schooling, and total fertility rate. FINDINGS: Total global DALYs remained largely unchanged from 1990 to 2015, with decreases in communicable, neonatal, maternal, and nutritional (Group 1) disease DALYs offset by increased DALYs due to non-communicable diseases (NCDs). Much of this epidemiological transition was caused by changes in population growth and ageing, but it was accelerated by widespread improvements in SDI that also correlated strongly with the increasing importance of NCDs. Both total DALYs and age-standardised DALY rates due to most Group 1 causes significantly decreased by 2015, and although total burden climbed for the majority of NCDs, age-standardised DALY rates due to NCDs declined. Nonetheless, age-standardised DALY rates due to several high-burden NCDs (including osteoarthritis, drug use disorders, depression, diabetes, congenital birth defects, and skin, oral, and sense organ diseases) either increased or remained unchanged, leading to increases in their relative ranking in many geographies. From 2005 to 2015, HALE at birth increased by an average of 2·9 years (95% uncertainty interval 2·9-3·0) for men and 3·5 years (3·4-3·7) for women, while HALE at age 65 years improved by 0·85 years (0·78-0·92) and 1·2 years (1·1-1·3), respectively. Rising SDI was associated with consistently higher HALE and a somewhat smaller proportion of life spent with functional health loss; however, rising SDI was related to increases in total disability. Many countries and territories in central America and eastern sub-Saharan Africa had increasingly lower rates of disease burden than expected given their SDI. At the same time, a subset of geographies recorded a growing gap between observed and expected levels of DALYs, a trend driven mainly by rising burden due to war, interpersonal violence, and various NCDs. INTERPRETATION: Health is improving globally, but this means more populations are spending more time with functional health loss, an absolute expansion of morbidity. The proportion of life spent in ill health decreases somewhat with increasing SDI, a relative compression of morbidity, which supports continued efforts to elevate personal income, improve education, and limit fertility. Our analysis of DALYs and HALE and their relationship to SDI represents a robust framework on which to benchmark geography-specific health performance and SDG progress. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform financial and research investments, prevention efforts, health policies, and health system improvement initiatives for all countries along the development continuum. FUNDING: Bill & Melinda Gates Foundation

Measuring the health-related Sustainable Development Goals in 188 countries : a baseline analysis from the Global Burden of Disease Study 2015

Background In September, 2015, the UN General Assembly established the Sustainable Development Goals (SDGs). The SDGs specify 17 universal goals, 169 targets, and 230 indicators leading up to 2030. We provide an analysis of 33 health-related SDG indicators based on the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015). Methods We applied statistical methods to systematically compiled data to estimate the performance of 33 health-related SDG indicators for 188 countries from 1990 to 2015. We rescaled each indicator on a scale from 0 (worst observed value between 1990 and 2015) to 100 (best observed). Indices representing all 33 health-related SDG indicators (health-related SDG index), health-related SDG indicators included in the Millennium Development Goals (MDG index), and health-related indicators not included in the MDGs (non-MDG index) were computed as the geometric mean of the rescaled indicators by SDG target. We used spline regressions to examine the relations between the Socio-demographic Index (SDI, a summary measure based on average income per person, educational attainment, and total fertility rate) and each of the health-related SDG indicators and indices. Findings In 2015, the median health-related SDG index was 59.3 (95% uncertainty interval 56.8-61.8) and varied widely by country, ranging from 85.5 (84.2-86.5) in Iceland to 20.4 (15.4-24.9) in Central African Republic. SDI was a good predictor of the health-related SDG index (r(2) = 0.88) and the MDG index (r(2) = 0.2), whereas the non-MDG index had a weaker relation with SDI (r(2) = 0.79). Between 2000 and 2015, the health-related SDG index improved by a median of 7.9 (IQR 5.0-10.4), and gains on the MDG index (a median change of 10.0 [6.7-13.1]) exceeded that of the non-MDG index (a median change of 5.5 [2.1-8.9]). Since 2000, pronounced progress occurred for indicators such as met need with modern contraception, under-5 mortality, and neonatal mortality, as well as the indicator for universal health coverage tracer interventions. Moderate improvements were found for indicators such as HIV and tuberculosis incidence, minimal changes for hepatitis B incidence took place, and childhood overweight considerably worsened. Interpretation GBD provides an independent, comparable avenue for monitoring progress towards the health-related SDGs. Our analysis not only highlights the importance of income, education, and fertility as drivers of health improvement but also emphasises that investments in these areas alone will not be sufficient. Although considerable progress on the health-related MDG indicators has been made, these gains will need to be sustained and, in many cases, accelerated to achieve the ambitious SDG targets. The minimal improvement in or worsening of health-related indicators beyond the MDGs highlight the need for additional resources to effectively address the expanded scope of the health-related SDGs.Peer reviewe

Kompensation der Kerr-Nichtlinearität basierend auf polarisationsunabhängigen faseroptischen parametrischen Verstärkern in hochratigen optischen Übertragungssystemen

Kerr nonlinearity compensation in long-haul optical transmission networks has become necessary since the nonlinear impairment poses fundamental limits on the achievable transmission reach. Mid-link spectral inversion technique employing Fiber-based optical parametric amplifier (FOPA)s exhibit the capabilities for nonlinearity compensation through optical phase conjugation (OPC). However, the implementation of FOPAs in practical transmission systems is limited by their inherent polarization-dependent nature. Nevertheless, FOPAs employing the polarization-diversity loop scheme can be operated as polarization-independent optical sub-systems. The presence of Brillouin scattering in the diversity loop can degrade data signals significantly. This thesis focuses on the experimental investigation of the stimulated Brillouin scattering (SBS)-induced distortions in a polarization-independent FOPA based on the polarization-diversity loop scheme. Initially, a single–pump polarization-independent FOPA using a polarization-maintaining highly nonlinear fiber (PM-HNLF) in the diversity loop is experimentally investigated. Parametric on-off gain for up to 20 dB, using a continuous wave (CW) signal and a 28-GBd single-polarization (SP) quadrature phase-shift keying (QPSK) data signal, are used in the investigation. It is shown that Brillouin scattering between the counter-propagating pumps in the diversity loop yields polarization-dependent gain (PDG) if an asymmetric local dispersion profile of the used highly nonlinear fiber (HNLF) is present. In addition, a dual-pump polarization-independent FOPA is also designed and experimentally investigated in terms of amplification and wavelength conversion for OPC applications. A 28-GBd polarization-division multiplexed (PDM) 16-ary quadrature amplitude modulation (16-QAM) signal in a 50-GHz spaced five-channel wavelength-division multiplexing (WDM) system is used in the investigation. Mid-link spectral inversion technique employing the OPC device is used for nonlinearity compensation of 5×28-GBd PDM 16-QAM signal transmission over both a dispersion-compensated link and a dispersion-uncompensated link. A significant increase in nonlinear tolerance is demonstrated. The performance of the mid-link OPC is compared with digital back-propagation algorithm employing the split-step Fourier method for nonlinearity compensation. Signal transmission over up to 800-km of dispersion-compensated link shows that in the single-channel case, the use of the back-propagation algorithm outperformed the OPC. However, with reference to the hard-decision forward-error correction (HD-FEC) threshold, signal transmission was not possible with digital back-propagation in the WDM scenario over the same link length while it was enabled by the OPC.Diese Arbeit ist fokussiert auf die experimentelle Untersuchung von streuungsbedingten Störungen in polarisationsunabhängigen Fiber-based optical parametric amplifiers (FOPAs), welche auf dem polarisationsdiversen Faserring-Schema basieren. Zunächst wird ein solches Schema in einer Konfiguration mit einem einzelnen Pumpsignal und einer polarisationserhaltenden hochnichtlinearen Faser (HNLF) für Verstärkungen bis zu 20 dB untersucht. Als Eingangssignal wird sowohl ein unmoduliertes Signal als auch ein Single–Polarisation 28-GBd QPSK-moduliertes Signal verwendet. Die im FOPA erzeugten Signalstörungen wurden untersucht und es konnte gezeigt werden, dass Brillouin-Streuung zwischen dem gegenläufigen Pumpsignal im Faserring zu polarisationsabhängiger Verstärkung führt, wenn die HNLF ein asymmetrisches Dispersionsprofil besitzt. Zusätzlich wurde ein Versuchsaufbau realisiert, bei dem zwei Pumpsignale im polarisationsdiversen Faserring-Schema eingesetzt werden. Dieser wurde zum einen in Bezug auf Signalverstärkung charakterisiert und zum anderen für Wellenlängenumsetzung für OPC-Anwendungen. Hierbei wurden 28-GBd polarisations gemultiplexte (PDM) 16-QAM Signale in einem fünf-Kanal–Wellenlängenmultiplex (WDM)-System mit 50 GHz Kanalabstand verwendet. Die Technik der Mid-Link spektralen Inversion wurde mit dem realisierten OPC-Aufbau für die Kompensation von nichtlinearen Signalstörungen in einem 5×28-GBd PDM 16-QAM Übertragungssystem untersucht. Dies wurde für dispersionskompensierte als auch dispersionsunkompensierte Faserstrecken untersucht. Eine deutliche Vergrößerung der nichtlinearen Toleranz konnte hierbei demonstriert werden. Des Weiteren wurde die Güte der Signalübertragung mit der Technik der Digitalen-Rückwärtsausbreitung verglichen, die auf einer Split-Step-Fourier-Methode basiert und ebenso nichtlineare Signalstörungen kompensieren kann. Übertragungsexperimente wurden bis zu einer Distanz von 800km durchgeführt. Im Einkanalfall konnte eine deutlich bessere Signalübertragungsgüte bei Nutzung der digitalen Rückwärtsausbreitung erzielt werden. Hingegen war die Übertragung im WDM-Fall nur mit der Nutzung des OPC-Aufbaus für die anvisierte Signalgüte erzielbar.DFG, GR 3774/1-1,2, Fiber-based optical parametric amplifiers (FOPAs) for signal regeneration in transmission links with higher-order modulation format

Proximate composition and mineral profile of elephants forages in the Savannah ecological zone of Ghana

ABSTRACTThis study evaluated the proximate and mineral composition of various parts of Balanites aegyptiaca, Mitragyna inermis, Cassia sieberiena, Kigelia africana, Detarium microcarpum, Terminalia laxiflora, Ficus platyphylla and Climber plant (Liana) as feeds of elephants in the savannah ecological zone of Ghana. The proximate composition was carried out using the methods of the Association of official analytical chemists (AOAC) and the mineral profiles were determined by atomic absorption and flame photometric methods. The highest content of Crude Protein, Crude Fibre, Ash, Moisture and Nitrogen free extract were 12.0% ± 0.01, 15.3% ± 0.01, 14.6% ± 0.0, 7.5% ± 0.01, 76.6% ± 0.01 for Ficus platyphylla, Tamarindus indica, Balanites aegyptiaca and Detarium microcarpum, respectively. The mineral profiling also found appreciable levels of Ca, Mg, P, K, Na, Zn, Cu, Fe, Se and Mn at concentrations (mg/kg) of 4.6 ± 0.00, 0.4 ± 0.01, 0.4 ± 0.01, 5.1 ± 0.01, 0.11 ± 0.01, 1.07 ± 0.008, 0.25 ± 0.005, 0.063 ± 0.0005, 37.48 ± 0.001 for Ficus platyphylla bark, Liana, Terminalia laxiflora bark and leaves, Mitragyna inermis bark, Terminalia laxiflora leaves and Mitragyna inermis leaves, respectively. Presentation of the presence of these important nutrients would be a guide to zoo managers and wildlife practitioners on the best quality of feeds to select for wild elephants