91 research outputs found
Risk assessment of the total mercury in Golden gray mullet (Liza aurata) from Caspian Sea
Mercury is the most toxic heavy metal in the aquatic ecosystems which originates both from natural and industrial resources and is ultimately deposited in sediments as methyl mercury. This metal is quickly transferred through the food chain and accumulated in organisms. In this study, the human health risk due to consumption of Mullet (Liza aurata) in the Caspian Sea, were evaluated by measuring the concentration of mercury in muscle samples using Atomic absorbtion spectrophotometer (Perkin Elmer FIAS-100) and cold vapor technique. A total of 60 fresh Mullet samples were collected by local fisherman from 12 stations on the southern coast of Caspian Sea in Mazandaran province situated in the north of Iran. The average concentration of mercury in Mullet muscle was 0.137 µg/g of fresh weight (0.432 µg/g dry weight) which was less than the allowable amount for human consumption determined by the international organizations such as United States Environmental Protection Agency, World Health Organization, Food and Agriculture Organizations and the Food and Drug Administration. The calculations indicated that daily and weekly mercury uptake for Iranian consumers is lower than the guide values (Acceptable Daily Intake and Provisional Tolerable Weekly Intake) provided by international organizations. Also, Hazard Quotient Index was below 1 (0.35). Therefore, the consumption of the Mullet is not a serious threat to the consumer’s health and a consumption permitted rate of 51 g per day is recommended
Morphological development and allometric growth patterns of Acipenser persicus Borodin, 1897 (Actinopterygii, Acipenseridae) during early development
Morphological development and allometric growth patterns of reared Persian sturgeon, Acipenser persicus, were studied from hatching to 50 days post-hatching (dph). The larvae were sampled, their left sides photographed and seven morphometric characters, including total length, head length, tail length, trunk length, snout length, caudal peduncle and predorsal length were measured. Allometric growth patterns were calculated as a power function of total length and described using the growth coefficient to find important steps in early life history. The total length of the newly hatched larvae and fry were 10.59±0.8 and 38.8±2.9 mm at 1 and 50 dph, respectively. Morphogenesis and differentiation were the highest rates during the first 11 days of early development, i.e. endogenous feeding period. There were higher growth rate of head, snout and tail regions compared with those of other organs from the hatch up to yolk sac absorption, followed by positive or almost isometric patterns, after the begin of exogenous feeding, showing priority to enhance the feeding and swimming capabilities. This study confirmed that most of morphological changes of this species are occurred from hatching until the onset of exogenous feeding i.e. during the lecithotrophic phase
Use of Duck weed (Lemna minor) meal in Caspian Kutum (Rutilus frisii kutum) diets and its effects on growth indices and carcass composition
In this study, in a completely randomized experimental design, the effects of different levels of duck weed (Lemna minor L.) meal in Caspian kutum diet on growth indices, carcass composition were investigated in an 8- week period. Different replacement levels of 0, 5, 10 and 15% were consisted the treatments in triplicates. Fingerlings with the mean initial weight of 2.02 ± 0.08 g were distributed in the experimental tanks. The results indicated that addition of duck weed powder in kutum diet more than 5% up to 15 caused a significant decrease (p 0.05). It was concluded that with increasing the duck weed levels in diet, lipid, protein and ash contents did not show any significant differences in fish carcasses compared to control (p>0.05), however moisture increased with increasing the rates of duck weed in the diet. Getting the same results of growth indices in treatment containing 5% duckweed and control (p>0.05), confirmed that duck weed can be used at the level of 5% in the kutum diet
Nuevo método de análisis de residuos de oxolínico y flumequina utilizando la detección de la fluorescencia nativa inducida por láser acoplada en el ultravioleta cercano acoplada al HPLC: comparación con la lámpara de xenon convencional
A new high-performance liquid chromatography (HPLC) method is described for the determination of oxolinic acid
and flumequine, with ultraviolet laser-induced fluorescence detection (UV-LIFD). Near-UV excitation at 325 nm
was obtained by using an He/Cd laser. Data obtained using UV-LIFD and conventional fluorimetry (Xenon flash,
lexc 325/ lem 365) are compared under the same chromatographic conditions, connecting in series both detectors, in
terms of linearity, reproducibility and repeatability. The HPLC separation is carried out on a Synergi MAX-RP
column with water–acetonitrile (2:1, v/v) adjusted at pH 2.5, with formic acid, as mobile phase and completed in less
than 9 min. The detection limits of oxolinic acid and flumequine at a signal-to-noise ratio of 3 were 0.43 pg and
0.76 pg on column with UV-LIFD detection, making this method considerably more sensitive than traditional
fluorescence detector (16.15 pg and 14.17 pg) having some obvious advantagesEn este trabajo proponemos un nuevo método de cromatografía líquida de alta eficacia para el análisis de ácido
oxolínico y flumequina con detección por fluorescencia inducida por Láser. La excitación ultravioleta cercana a
325 nm se obtiene usando un laser HE/Cd. Los datos obtenidos usando esta excitación se compararon con los
obtenidos por fluorescencia normal (Xenon flash, lexc 325/lem 365) en las mismas condiciones cromatográficas,
conectando en serie los dos detectores, en términos de linearidad, reproducibilidad y repetibilidad. La separación por
HPLC se llevó a cabo con una columna Synergi MAX-RP con una fase móvil agua/acetonitrilo (2:1, V/V) ajustada
a pH 2.5 con ácido fórmico, completándose en menos de 9 min. Los límites de detección, para una señal/ruido de 3,
fueron 0.43 pg y 0.76 pg en columna para oxolínico y flumequina respectivamente, haciendo este método
considerablemente más sensible que el tradicional detector por fluorescencia (16.15 pg y 14.17 pg), lo que tiene
ventajas obviasXesús Feás acknowledges a scholarship within the program
‘‘Formación de Personal Investigador’’ from Ministerio de
Ciencia y Tecnología, Spain, and Ana Carreira for technical
collaborationS
Simulation and Analysis of Land Subsidence Phenomenon Using Poroelasticity Theory (Case Study: Tehran-Shahriar Plain)
Indiscriminate extraction of underground water sources causes a drop in the water level and an increase in the stress on the soil particles, which leads to the subsidence of the earth's surface. Shahryar's critical plain has been affected by the phenomenon of subsidence for the past few years. The existence of vital arteries, economic, pilgrimage and military areas has turned it into a strategic area, which doubles the cost of the harmful consequences of subsidence. In this research, a new method is used to predict and analyze subsidence, under the title of Poroelasticity module of COMSOL software, which uses the simultaneous solution of equations related to fluid movement in porous media and mechanical deformation. The output of the numerical model was validated and compared between 2003 and 2019 at 24 points with the alignment observations, the Sentinel 1 radar interferometric images. The correlation coefficient of 0.97 indicates an acceptable correlation between the data values, the good matching of the interferometric images with the maps of the subsidence zones obtained from the software data and the approach of the squared values of the mean squared error and the efficiency coefficient towards zero and one was obtained. The general result of the finite element numerical modeling showed that the average rate of subsidence during the year 2031 due to the successive compression of the upper layers of the aquifer, with a lower rate, about 13.19 cm and in the places where the thickness of the fine-grained layers increased, He finds that it will reach 18.38 cm. Also, the range of changes in the underground water level in the period of time, the type of land and the number of geological units are among the factors affecting the subsidence pattern and rate
Assessment of essential elements in the wild Beluga Sturgeon (Huso huso) caviar from Caspian Sea
In this study, the concentration of Calcium (Ca), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Selenium (Se) and Zinc (Zn) as essential metals, were determined in caviar of wild beluga sturgeon caught from the Caspian Sea in March 2012. Potassium (4885.51± 17.81 µg g-1) and Magnesium (346.61± 6.6 µg g-1) had the highest concentration and Cobalt and Manganese levels were less than 0.01 mg kg-1 wet weight. The mean concentration of Copper and Zinc in the caviar samples were under the permissible limits proposed by the UK’s Ministry of Agriculture, Fisheries and Foods. The caviar maximum allowable daily consumption rate was calculated. However, the health risks from caviar consumption are uncertain because the amount of caviar consumed by heavy users is not known
Exploration of digital entrepreneurship – online home based businesses through empirical analysis
Digital entrepreneurship is a broad domain and includes businesses predominantly operating online, such as online retailers, portals, community sites and also businesses providing services to enable other businesses to operate online, such as web designers, platform providers and operators. This research focused online home based businesses on any stage of business development, for example start-up or grown, and focus on any aspect, such as raising finance, establishing networks or developing marketing approaches. This research uses systematic review and empirical analysis considering the theoretical lens of effectuation as research methods.
The outcomes of this research are:
• Characteristics of online home based entrepreneurs and businesses, and developed a model of entrepreneur-venture fit
• Certain challenging demands, such as engendering feelings of isolation
• Entrepreneurial opportunities to groups and individuals who may be otherwise excluded
This study is important since it provides empirical evidence and a theoretically grounded understanding of how online businesses offer the opportunity to break out of the low growth, low margin and enter high growth, high margin, post-industrial sectors. In future, we plan to work on grey literature related to online home based businesses
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
Measuring routine childhood vaccination coverage in 204 countries and territories, 1980-2019 : a systematic analysis for the Global Burden of Disease Study 2020, Release 1
Background Measuring routine childhood vaccination is crucial to inform global vaccine policies and programme implementation, and to track progress towards targets set by the Global Vaccine Action Plan (GVAP) and Immunization Agenda 2030. Robust estimates of routine vaccine coverage are needed to identify past successes and persistent vulnerabilities. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020, Release 1, we did a systematic analysis of global, regional, and national vaccine coverage trends using a statistical framework, by vaccine and over time. Methods For this analysis we collated 55 326 country-specific, cohort-specific, year-specific, vaccine-specific, and dosespecific observations of routine childhood vaccination coverage between 1980 and 2019. Using spatiotemporal Gaussian process regression, we produced location-specific and year-specific estimates of 11 routine childhood vaccine coverage indicators for 204 countries and territories from 1980 to 2019, adjusting for biases in countryreported data and reflecting reported stockouts and supply disruptions. We analysed global and regional trends in coverage and numbers of zero-dose children (defined as those who never received a diphtheria-tetanus-pertussis [DTP] vaccine dose), progress towards GVAP targets, and the relationship between vaccine coverage and sociodemographic development. Findings By 2019, global coverage of third-dose DTP (DTP3; 81.6% [95% uncertainty interval 80.4-82 .7]) more than doubled from levels estimated in 1980 (39.9% [37.5-42.1]), as did global coverage of the first-dose measles-containing vaccine (MCV1; from 38.5% [35.4-41.3] in 1980 to 83.6% [82.3-84.8] in 2019). Third- dose polio vaccine (Pol3) coverage also increased, from 42.6% (41.4-44.1) in 1980 to 79.8% (78.4-81.1) in 2019, and global coverage of newer vaccines increased rapidly between 2000 and 2019. The global number of zero-dose children fell by nearly 75% between 1980 and 2019, from 56.8 million (52.6-60. 9) to 14.5 million (13.4-15.9). However, over the past decade, global vaccine coverage broadly plateaued; 94 countries and territories recorded decreasing DTP3 coverage since 2010. Only 11 countries and territories were estimated to have reached the national GVAP target of at least 90% coverage for all assessed vaccines in 2019. Interpretation After achieving large gains in childhood vaccine coverage worldwide, in much of the world this progress was stalled or reversed from 2010 to 2019. These findings underscore the importance of revisiting routine immunisation strategies and programmatic approaches, recentring service delivery around equity and underserved populations. Strengthening vaccine data and monitoring systems is crucial to these pursuits, now and through to 2030, to ensure that all children have access to, and can benefit from, lifesaving vaccines. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019
Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
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