Data-based investigation of the effects of canopy structure and shadows on chlorophyll fluorescence in a deciduous oak forest

Data from satellite, aircraft, drone, and ground-based measurements have already shown that canopy-scale sun-induced chlorophyll fluorescence (SIF) is tightly related to photosynthesis, which is linked to vegetation carbon assimilation. However, our ability to effectively use those findings are hindered by confounding factors, including canopy structure, fluctuations in solar radiation, and sun–canopy geometry that highly affect the SIF signal. Thus, disentangling these factors has become paramount in order to use SIF for monitoring vegetation functioning at the canopy scale and beyond. Active chlorophyll fluorescence measurements (FyieldLIF), which directly measures the apparent fluorescence yield, have been widely used to detect physiological variation of the vegetation at the leaf scale. Recently, the measurement of FyieldLIF has become feasible at the canopy scale, opening up new opportunities to decouple structural, biophysical, and physiological components of SIF at the canopy scale. In this study, based on top-of-canopy measurements above a mature deciduous forest, reflectance (R), SIF, SIF normalized by incoming photosynthetically active radiation (SIFy), FyieldLIF, and the ratio between SIFy and FyieldLIF (named Φk) were used to investigate the effects of canopy structure and shadows on the diurnal and seasonal dynamics of SIF. Further, random forest (RF) models were also used to not only predict FyieldLIF and Φk, but also provide an interpretation framework by considering additional variables, including the R in the blue, red, green, red-edge, and near-infrared bands; SIF; SIFy; and solar zenith angle (SZA) and solar azimuth angle (SAA). Results revealed that the SIF signal is highly affected by the canopy structure and sun–canopy geometry effects compared to FyieldLIF. This was evidenced by the weak correlations obtained between SIFy and FyieldLIF at the diurnal timescale. Furthermore, the daily mean SIF‾y captured the seasonal dynamics of daily mean F‾yieldLIF and explained 58 % of its variability. The findings also revealed that reflectance in the near-infrared (R-NIR) and the NIRv (the product of R-NIR and normalized difference vegetation index (NDVI)) are good proxies of Φk at the diurnal timescale, while their correlations with Φk decrease at the seasonal timescale. With FyieldLIF and Φk as outputs and the abovementioned variables as predictors, this study also showed that the RF models can explain between 86 % and 90 % of FyieldLIF, as well as 60 % and 70 % of Φk variations under clear-sky conditions. In addition, the predictor importance estimates for FyieldLIF RF models revealed that R at 410, 665, 740, and 830 nm; SIF; SIFy; SZA; and SAA emerged as the most useful and influential factors for predicting FyieldLIF, while R at 410, 665, 705, and 740 nm; SZA; and SAA are crucial for predicting Φk. This study highlighted the complexity of interpreting diurnal and seasonal dynamics of SIF in forest canopies. These dynamics are highly dependent on the complex interactions between the structure of the canopy, the vegetation biochemical properties, the illumination angles (SZA and SAA), and the light conditions (ratio of diffuse to direct solar radiation). However, such measurements are necessary to better separate the variability in SIF attributable to radiation and measurement conditions from the subtler variability attributable to plant physiological processes.</p

Household experience and costs of seeking measles vaccination in rural Guinea-Bissau.

OBJECTIVES: Children younger than 12 months of age are eligible for childhood vaccines through the public health system in Guinea-Bissau. To limit open vial wastage, a restrictive vial opening policy has been implemented; 10-dose measles vaccine vials are only opened if six or more children aged 9-11 months are present at the vaccination post. Consequently, mothers who bring their child for measles vaccination can be told to return another day. We aimed to describe the household experience and estimate household costs of seeking measles vaccination in rural Guinea-Bissau. METHODS: Within a national sample of village clusters under demographic surveillance, we interviewed mothers of children aged 9-21 months about their experience with seeking measles vaccination. From information about time and money spent, we calculated household costs of seeking measles vaccination. RESULTS: We interviewed mothers of 1308 children of whom 1043 (80%) had sought measles vaccination at least once. Measles vaccination coverage was 70% (910/1308). Coverage decreased with increasing distance to the health centre. On average, mothers who had taken their child for vaccination took their child 1.4 times. Mean costs of achieving 70% coverage were 2.04 USD (SD 3.86) per child taken for vaccination. Half of the mothers spent more than 2 h seeking vaccination and 11% spent money on transportation. CONCLUSIONS: We found several indications of missed opportunities for measles vaccination resulting in suboptimal coverage. The household costs comprised 3.3% of the average monthly income and should be taken into account when assessing the costs of delivering vaccinations

Mejora de la productividad del almac?n en una empresa comercializadora mediante la implementaci?n de la gesti?n de inventarios

El presente estudio tiene como objetivo principal determinar la influencia de la Gesti?n de Inventarios en la mejora de la productividad del almac?n de la empresa comercializadora WANCORE S.A. y objetivos espec?ficos; establecer la contribuci?n de la rotaci?n de inventarios y la valorizaci?n de los inventarios en la entrega de pedidos sin errores. As? mismo, el ?ltimo objetivo espec?fico buscar determinar la influencia de la exactitud de inventarios sobre el cumplimiento a tiempo de los despachos. La investigaci?n es de tipo aplicada correlacional, con un dise?o cuasi-experimental. La aplicaci?n de las herramientas de la Gesti?n de Inventarios logr? solucionar el inconveniente de la baja productividad; porque la empresa empez? a reportar altos ?ndices de devoluci?n de pedidos, p?rdidas de mercader?a, despachos atendidos fuera de tiempo, errores en la preparaci?n de pedidos, entre otros motivos. Por ello, con la intervenci?n de la gesti?n de inventarios, la productividad del almac?n logr? mejorar; ya que se obtuvo un incremento del 20%. Finalmente, la conclusi?n principal es la determinaci?n de la contribuci?n total del sistema en la mejora de la productividad

Induction of apoptosis in host cells: a survival mechanism for Leishmania parasites?

Leishmania parasites invade host macrophages, causing infections that are either limited to skin or spread to internal organs. In this study, 3 species causing cutaneous leishmaniasis, L. major, L. aethiopica and L. tropica, were tested for their ability to interfere with apoptosis in host macrophages in 2 different lines of human monocyte-derived macrophages (cell lines THP-1 and U937) and the results confirmed in peripheral blood mononuclear cells (PBMC). All 3 species induced early apoptosis 48 h after infection (expression of phosphatidyl serine on the outer membrane). There were significant increases in the percentage of apoptotic cells both for U937 and PBMC following infection with each of the 3 species. Early apoptotic events were confirmed by mitochondrial membrane permeabilization detection and caspase activation 48 and 72 h after infection. Moreover, the percentage of infected THP-1 and U937 macrophages increased significantly (up to 100%) following treatment with an apoptosis inducer. Since phosphatidyl serine externalization on apoptosing cells acts as a signal for engulfment by macrophages, induction of apoptosis in the parasitized cells could actively participate in spreading the infection. In summary, parasite-containing apoptotic bodies with intact membranes could be released and phagocytosed by uninfected macrophages

Prevalence and awareness of diabetes in Guinea: findings from a WHO STEPS

Aims: The aim of the present study was to determine the prevalence of diabetes, and to assess its awareness and related risk factors among adult Guineans.Methods: A population-based cross-sectional survey was conducted on 1 100  adults (46.6% women) aged 35–64 years from Lower Guinea, during September to December 2009, using the WHO STEPwise approach of surveillance of chronic  disease risk factors. Data were collected in three steps: demographic and  behavioural risk factors, blood pressure and anthropometric measurements, and fasting blood cholesterol and glucose testing. A multi-stage cluster sample design was applied to generate nationwide representative data.Results: The mean age of all participants was 47.3 years (SD 8.8), similarly in  Conakry, rural Lower Guinea and urban Lower Guinea. The prevalence of diabetes was 5.7% (95% CI 4.0–8.1). Among participants with diabetes, only 44.0% were aware of their status. In multivariable logistic regression analysis, determinants of diabetes prevalence were urban residency, male sex, age group 45–64 years, increased waist circumference, hypertension and hypercholesterolemia. Male sex, rural residency, age group 45–54 years, no formal education, waist circumference, hypertension and hypercholesterolemia were independent predictors of screen-detected diabetes.Conclusion: The present study found a high prevalence and low awareness of  diabetes, suggesting the need for appropriate actions to strengthen primary  healthcare approaches towards non-communicable diseases in Guinea.Keywords: Diabetes, epidemiology, Guine

Features of <i>ESCHERICHIA COLI</i> samples from patients with diarrheal syndrome in the Republic of Guinea

Introduction. Diarrheal diseases are a global public health issue and cause 15% of deaths in children under 5 years old, of which about 80% occur in the regions of Africa and Southeast Asia. According to the Global Enteric Multicentre Study (GEMS) conducted in a number of African countries, one of the leading pathogens of high risk of death in infants and young children is diarrheagenic E. coli (DEC). In recent decades, antimicrobial resistance (AMR) has become globally ubiquitous. The Republic of Guinea urgently needs large-scale studies devoted to assessing DEC distribution and antibiotic resistance. The purpose of the study is to assess the pattern of E. coli infections and to test the susceptibility to antibiotics in strains of diarrheagenic E. coli sampled from individuals residing in the Republic of Guinea. Materials and methods. From 2019 to 2022, we studied 724 samples of faeces of patients with acute diarrhea, among them 72 (9.9%) children aged 1–5 years, 128 (17.7%) children aged 6–17 years, and 524 (72.4%) people aged 18 years and older; a method of polymerase chain reaction (PCR) was applied with the use of the AmpliSense® Escherichioses-FL reagent kit to identify the genetic determinants of DEC: EPEC, EHEC, ETEC, EIEC, and EAgEC (Central Research Institute of Epidemiology of Rospotrebnadzor, Russia). Susceptibility to 15 antimicrobial agents was found by the disc-diffusion method using Mueller–Hinton agar (Russia) and Oxoid discs (UK). Results were interpreted according EUCAST criteria, versions 2019–2022 (https://www.eucast.org/ast_of_bacteria/previous_versions_of_documents). Results. For the period from 2019 to 2022, the percentage of E. coli infections in the etiological pattern of acute intestinal infections amounted to 51.7%. In the age-related manner, DEC was significantly more common in young children aged 0–5 (96.9%, p 0.05) as compared to school age children aged 6–17 (53.9%) and adults (45.6%). In all years of observation, EAgEC strains prevailed, accounting for 38.4%. Other DEC pathotypes, EPEC, ETEC, EIEC and STEC, accounted for 27.2%, 17.5%, 11.8%, and 5.1%, respectively. DEC strains are susceptible to meropenem, amikacin, and nitrofurantoin. The activity of other antibiotics ranged from 11.3% for ampicillin, 28.3% for trimethoprim-sulfamethoxazole, and 34.0% for tetracycline to 73.6% for cephalosporins, 84.0% for aminoglycosides, and 98.1% for fluorinated quinolones. Conclusion. To reduce the burden of diarrheal diseases in the Republic of Guinea, it may be necessary to conduct targeted epidemiological and microbiological studies to identify DEC and monitor the development of antimicrobial resistance of E. coli infection pathogens in the population