bluuebunny/crossref_metadata_2025 huggingface dataset:
Intelligent System for Vehicles Number Plate Detection and Recognition Using Convolutional Neural Networks
Authors: Alam Nur-A- , Ahsan Mominul , Based Md. Abdul , Haider Julfikar
Published: January 2021

Vehicles on the road are rising in extensive numbers, particularly in proportion to the industrial revolution and growing economy. The significant use of vehicles has increased the probability of traffic rules violation, causing unexpected accidents, and triggering traffic crimes. In order to overcome these problems, an intelligent traffic monitoring system is required. The intelligent system can play a vital role in traffic control through the number plate detection of the vehicles. In this research work, a system is developed for detecting and recognizing of vehicle number plates using a convolutional neural network (CNN), a deep learning technique. This system comprises of two parts: number plate detection and number plate recognition. In the detection part, a vehicle’s image is captured through a digital camera. Then the system segments the number plate region from the image frame. After extracting the number plate region, a super resolution method is applied to convert the low-resolution image into a high-resolution image. The super resolution technique is used with the convolutional layer of CNN to reconstruct the pixel quality of the input image. Each character of the number plate is segmented using a bounding box method. In the recognition part, features are extracted and classified using the CNN technique. The novelty of this research is the development of an intelligent system employing CNN to recognize number plates, which have less resolution, and are written in the Bengali language.
Acute Changes in Thyroid Hormone Levels among Thai Pesticide Sprayers
Authors: Kongtip Pornpimol , Nankongnab Noppanun , Pundee Ritthirong , Kallayanatham Nichcha , Pengpumkiat Sumate , Chungcharoen Jutamanee , Phommalachai Chavisa , Konthonbut Pajaree , Choochouy Nattagorn , Sowanthip Preecha , Khangkhun Phanthawee , Yimsabai Jutharak , Woskie Susan
Published: January 2021

The objective of this study was to investigate the relationship of acute pesticide exposures and acute changes in thyroid hormones among Thai farmers. We recruited 78 farmers, who were scheduled to spray insecticides (chlorpyrifos and/or cypermethrin) or herbicides (paraquat and/or glyphosate). On the day before spraying, farmers collected their first morning void urine and went for blood collection. On the spray day, urine samples were collected at end of the spraying event and they were interviewed with questionnaires. The next morning, the first morning void urine and blood samples were collected. Blood samples were analyzed for thyroid hormones. Urine samples were analyzed for the metabolites of the pesticide sprayed. The results showed that the thyroid hormones, free triiodothyronine (FT3) and total triiodothyronine (T3) were significantly reduced as urinary chlorpyrifos metabolite increased the day after spraying. Total thyroxine (T4) significantly increased as cypermethrin metabolites increased the day after spraying. T4 significantly increased as urinary glyphosate levels increased; however, FT3 and T3 decreased significantly as urinary paraquat levels increased the day after spraying. These findings suggest that acute exposures to the pesticides chlorpyrifos, cypermethrin, paraquat and glyphosate can produce acute effects on the hypothalamic–pituitary–thyroid (HPT) axis, acutely altering thyroid hormone levels.
Enhanced Photocatalytic Removal of Cyanotoxins by Al-Doped ZnO Nanoparticles with Visible-LED Irradiation
Authors: Benamara Majdi , Gómez Elvira , Dhahri Ramzi , Serrà Albert
Published: January 2021

The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR), and anatoxin-A were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption isotherms. With both cyanotoxins, increasing the Al content enhances the degradation kinetics, hence the use of nanoparticles with 5 at.% Al content (A5ZO). The dosage affected both cyanotoxins similarly, and the photocatalytic degradation kinetics improved with photocatalyst concentrations between 0.5 and 1.0 g L−1. Nevertheless, the pH study revealed that the chemical state of a species decisively facilitates the mutual interaction of cyanotoxin and photocatalysts. A5ZO nanoparticles achieved better outcomes than other photocatalysts to date, and after 180 min, the mineralization of anatoxin-A was virtually complete in weak alkaline medium, whereas only 45% of MC-LR was in neutral conditions. Moreover, photocatalyst reusability is clear for anatoxin-A, but it is adversely affected for MC-LR.
Special Issue: Immune Dysfunction in Uremia
Authors: Cohen Gerald , Vanholder Raymond
Published: January 2021

This Special Issue of Toxins focusses on the interconnected factors interfering with the immune response in uremic patients [...]
Urological Complications in Kidney Transplant Recipients: Analysis of the Risk Factors and Impact on Transplant Outcomes in the Era of “Extended Criteria Donors”
Authors: Angelico Roberta , Pellicciaro Marco , Venza Francesca , Manzia Tommaso , Cacciola Roberto , Anselmo Alessandro , Toti Luca , Monaco Andrea , Iaria Giuseppe , Tisone Giuseppe
Published: January 2021

Urological complications (UC) following kidney transplantation (KT) are associated with increased morbidity. The aim of this study is to evaluate the risk factors for UC in the era of “extended criteria donors” (ECD) and their impact on patient and graft survivals. A retrospective monocentric study of all patients undergoing KT from 2010 to 2019 with a follow-up ≥30 days was performed. Out of 459 patients (males: 296 (64.5%); age: 57 (19–77) years) enrolled, 228 (49.7%) received ECD organs, moreover, 166 (67.2%) grafts had a cold ischemia time ≥10 h. UCs were reported in 32 (7%) patients. In 21 (65.6%) cases UC occurred within 3 months post-KT and 24 (5.2%) were associated with early urinary tract infection (UTI). The overall 5 year patient and graft survival rates were 96.5% and 90.6%, respectively. UC decreased graft survival (UC-group: 75.0% vs. noUC-group: 91.8%, p < 0.001), especially if associated with early UTI (UC-group: 71.4% vs. noUC-group: 77.8%, p < 0.001). At multivariate analysis, early UTI after KT (OR: 9.975, 95%-IC: 2.934–33.909, p < 0.001) and delayed graft function (DGF) (OR: 3.844, 95%-IC: 1.328–11.131, p: 0.013) were significant risk factors for UC, while ECD graft did not increase the risk of post-transplant UC. ECD grafts are not associated with UC. DGF and early UTI post-KT increase the risks of UC and reduce graft survival in the long-term. Therefore, aggressive management of early post-transplant UTI and strategies to reduce DGF incidence, such as machine preservation, are essential to prevent UC after KT.
Lessons Learned from Applying an Integrated Land Use Transport Planning Model to Address Issues of Social and Economic Exclusion of Marginalised Groups: The Case of Cape Town, South Africa
Authors: Tamuka Moyo Hazvinei Tsitsi , Zuidgeest Mark , van Delden Hedwig
Published: January 2021

The Group Areas Act of 1950 has resulted in post-apartheid South African cities being characterised by spatial patterns with limited access to social and economic opportunities for the black and coloured population. Typically, high-density low-income housing is located peripherally, while low density high-income housing is located in accessible central areas. With increased rural-to-urban migration, the demand for formal housing has historically surpassed supply, which has increased the growth of informal settlements. Current discourse within South African land use policy suggests that in-situ upgrading of informal housing is a viable response to integrate informal settlements into the formal city. In parallel, it is proposed that new low-income residential areas and employment-generating land uses should be located along transport corridors to improve access to transport, its infrastructure and the opportunities it provides for previously marginalised groups. This study uses Cape Town as a case city to explore two land-use driven development strategies directed at informal settlements and low-income housing. A dynamic land use transport model based on a cellular automata land use model and a four-stage transport model was used to simulate land use and transport changes. Specifically, in-situ upgrading of informal settlements and strategically locating new low-income residential and employment generating land uses along transport corridors were considered. The results from the analysis suggest that in-situ upgrading is a viable option only if new informal settlements are in areas with easy access to economic centres. With regards to low-income housing, targeted interventions aimed at ‘unlocking’ low-income housing activities along transport corridors were found to be useful. However, it was also observed that middle-income residential development and employment generating activities were also attracted to the same corridors, thus, resulting in mixed land uses, which is beneficial but can potentially result in rental bids between low and middle-income earners thus displacing low-income earners away from these areas.
Comparison of Two Hepatitis B Vaccination Strategies Targeting Vertical Transmission: A 10-Year Japanese Multicenter Prospective Cohort Study
Authors: Nishimura Koji , Yamana Keiji , Fukushima Sachiyo , Fujioka Kazumichi , Miyabayashi Hiroshi , Murabayashi Masao , Masunaga Ken , Okahashi Aya , Nagano Nobuhiko , Morioka Ichiro
Published: January 2021

In 1985, a hepatitis B (HB) vaccination strategy against vertical HB virus transmission was introduced in Japan that recommended vaccination of infants at two, three, and five months of age (delayed strategy). This schedule was revised in 2013, recommending to vaccinate at birth and at 1 and 6 months of age (non-delayed strategy). We aimed to compare the vertical HB virus transmission rates and immunogenic responses between these two vaccination strategies. This Japanese multicenter prospective cohort study included 222 infants born between 2008 and 2017 to serum hepatitis B surface (HBs) antigen (HBsAg)-positive mothers. During the study period, 136 and 86 infants received delayed and non-delayed strategies, respectively. A positive vertical HB virus transmission was defined as a positive serum HBsAg status. Seropositive immunogenic response was defined as a serum anti-HBs titer of ≥10 mIU/mL. Post-vaccination serum HBsAg positivity rates did not differ significantly between the delayed (0/136 [0.0%, 95% confidence interval, 0.0–2.7%]) and non-delayed (2/86 [2.3%, 95% confidence interval, 0.3–8.1%]) strategy groups. Seropositive immunogenic response rates were 100.0% (136/136) and 97.7% (84/86), respectively. Although this study was under-powered to detect a statistically significant result, no vertical HB virus transmission was observed in the delayed strategy.
A Scalable Manufacturing Approach to Single Dose Vaccination against HPV
Authors: Shao Shuai , Ortega-Rivera Oscar , Ray Sayoni , Pokorski Jonathan , Steinmetz Nicole
Published: January 2021

Human papillomavirus (HPV) is a globally prevalent sexually-transmitted pathogen, responsible for most cases of cervical cancer. HPV vaccination rates remain suboptimal, partly due to the need for multiple doses, leading to a lack of compliance and incomplete protection. To address the drawbacks of current HPV vaccines, we used a scalable manufacturing process to prepare implantable polymer–protein blends for single-administration with sustained delivery. Peptide epitopes from HPV16 capsid protein L2 were conjugated to the virus-like particles derived from bacteriophage Qβ, to enhance their immunogenicity. The HPV-Qβ particles were then encapsulated into poly(lactic-co-glycolic acid) (PLGA) implants, using a benchtop melt-processing system. The implants facilitated the slow and sustained release of HPV-Qβ particles without the loss of nanoparticle integrity, during high temperature melt processing. Mice vaccinated with the implants generated IgG titers comparable to the traditional soluble injections and achieved protection in a pseudovirus neutralization assay. HPV-Qβ implants offer a new vaccination platform; because the melt-processing is so versatile, the technology offers the opportunity for massive upscale into any geometric form factor. Notably, microneedle patches would allow for self-administration in the absence of a healthcare professional, within the developing world. The Qβ technology is highly adaptable, allowing the production of vaccine candidates and their delivery devices for multiple strains or types of viruses.
A Rapid Systematic Review of Public Responses to Health Messages Encouraging Vaccination against Infectious Diseases in a Pandemic or Epidemic
Authors: Lawes-Wickwar Sadie , Ghio Daniela , Tang Mei Yee , Keyworth Chris , Stanescu Sabina , Westbrook Juliette , Jenkinson Elizabeth , Kassianos Angelos P. , Scanlan Daniel , Garnett Natalie , Laidlaw Lynn , Howlett Neil , Carr Natalie , Stanulewicz Natalia , Guest Ella , Watson Daniella , Sutherland Lisa , Byrne-Davis Lucie , Chater Angel , Hart Jo , Armitage Christopher J. , Shorter Gillian W. , Swanson Vivien , Epton Tracy
Published: January 2021

Public health teams need to understand how the public responds to vaccination messages in a pandemic or epidemic to inform successful campaigns encouraging the uptake of new vaccines as they become available. A rapid systematic review was performed by searching PsycINFO, MEDLINE, healthevidence.org, OSF Preprints and PsyArXiv Preprints in May 2020 for studies including at least one health message promoting vaccine uptake of airborne-, droplet- and fomite-spread viruses. Included studies were assessed for quality using the Mixed Methods Appraisal Tool (MMAT) or the Assessment of Multiple Systematic Reviews (AMSTAR), and for patient and public involvement (PPI) in the research. Thirty-five articles were included. Most reported messages for seasonal influenza (n = 11; 31%) or H1N1 (n = 11; 31%). Evidence from moderate to high quality studies for improving vaccine uptake included providing information about virus risks and vaccination safety, as well as addressing vaccine misunderstandings, offering vaccination reminders, including vaccination clinic details, and delivering mixed media campaigns across hospitals or communities. Behavioural influences (beliefs and intentions) were improved when: shorter, risk-reducing or relative risk framing messages were used; the benefits of vaccination to society were emphasised; and beliefs about capability and concerns among target populations (e.g., vaccine safety) were addressed. Clear, credible, messages in a language target groups can understand were associated with higher acceptability. Two studies (6%) described PPI in the research process. Future campaigns should consider the beliefs and information needs of target populations in their design, including ensuring that vaccine eligibility and availability is clear, and messages are accessible. More high quality research is needed to demonstrate the effects of messaging interventions on actual vaccine uptake.
Modeling Insights into Precipitation Deuterium Excess as an Indicator of Raindrop Evaporation in Lanzhou, China
Authors: Chen Fenli , Zhang Mingjun , Argiriou Athanassios A. , Wang Shengjie , Ma Qian , Zhou Xin , Wu Xixi , Chen Jufan
Published: January 2021

The deuterium excess in precipitation is an effective indicator to assess the existence of sub-cloud evaporation of raindrops. Based on the synchronous measurements of stable isotopes of hydrogen and oxygen (δ2H and δ18O) in precipitation for several sites in Lanzhou, western China, spanning for approximately four years, the variations of deuterium excess between the ground and the cloud base are evaluated by using a one-box Stewart model. The deuterium excess difference below the cloud base during summer (−17.82‰ in Anning, −11.76‰ in Yuzhong, −21.18‰ in Gaolan and −12.41‰ in Yongdeng) is greater than that in other seasons, and difference in winter is weak due to the low temperature. The variations of deuterium excess in precipitation due to below-cloud evaporation are examined for each sampling site and year. The results are useful to understand the modification of raindrop isotope composition below the cloud base at a city scale, and the quantitative methods provide a case study for a semi-arid region at the monsoon margin.
Food Web Structure and Trophic Interactions Revealed by Stable Isotope Analysis in the Midstream of the Chishui River, a Tributary of the Yangtze River, China
Authors: Qin Qiang , Zhang Fubin , Liu Fei , Wang Chunling , Liu Huanzhang
Published: January 2021

Understanding energy flow and nutrient pathways is crucial to reveal the dynamics and functions of riverine ecosystems and develop appropriate conservation strategies. In this study, we utilized stable isotopes of δ13C and δ15N to examine the fundamental characteristics of trophic position, trophic niche, and carbon source for the food web in the midstream of the Chishui River, a tributary to the Yangtze River. Our results showed that stable isotope signatures among different sorts of basal resources and consumers were significantly distinguishable and that the food chain consisted of four trophic levels, indicating the multiple trophic pathways and long food chain length here. The trophic guilds of fish were classified into four categories, in which herbivorous and carnivorous fish showed greater trophic diversity and omnivorous fish had higher trophic redundancy, which meant that there was a stable trophic niche structure in the study area. Phytoplankton and periphyton presented the largest contributions to consumers, indicating that autochthonous productivity was the dominant carbon source in the midstream of the Chishui River. Since the Chishui River is still in a natural condition without any dam constructions, the autochthonous productivity, stable trophic niche structure, multiple trophic pathways and long food chain length found here demonstrate its high conservation value. Therefore, the strategy to refrain from damming on this river should persist into the future.
Physiological, Developmental, and Biomarker Responses of Zebrafish Embryos to Sub-Lethal Exposure of Bendiocarb
Authors: Gazsi Gyöngyi , Czimmerer Zsolt , Ivánovics Bence , Berta Izabella Roberta , Urbányi Béla , Csenki-Bakos Zsolt , Ács András
Published: January 2021

Bendiocarb is a broad-spectrum insecticide recommended for malaria control by the World Health Organization (WHO). Still, bendiocarb poses a toxic risk to populations of nontargeted aquatic organisms. Thus, our study was aimed to evaluate the sub-lethal effects of bendiocarb exposure on zebrafish (Danio rerio) embryos by assessing of physiological, developmental, and biochemical parameters. Bendiocarb-induced adverse effects on embryonic development, larval growth, heart rate, changes in phase II detoxifying enzyme glutathione-S-transferase (GST) activity, oxidative stress-related enzyme activities (superoxide dismutase (SOD), catalase (CAT)), and the damage-linked biomarker lipid peroxidation (LPO) in early life stage zebrafish were investigated. Our results highlight that the selected nonlethal concentrations (96 h median lethal concentration in this study was 32.52 mg/L−1) of bendiocarb inflicted adverse effects resulting in embryo deformities (96 h EC50 = 2.30 mg L−1), reduced body- and notochord length (above 0.75 and 0.39 mg L−1 bendiocarb concentrations at 96 hpf, respectively), oxidative stress, and altered heart rate (above 0.4 mg L−1 at 48 hpf) in the studied model system.
A Critical Review of Methods for Analyzing Freshwater Eutrophication
Authors: Zhang Yan , Li Mingxuan , Dong Jiefeng , Yang Hong , Van Zwieten Lukas , Lu Hui , Alshameri Aref , Zhan Zihan , Chen Xin , Jiang Xueding , Xu Weicheng , Bao Yanping , Wang Hailong
Published: January 2021

Water eutrophication is a global environmental problem that poses serious threats to aquatic ecosystems and human health. The evaluation of eutrophication provides a theoretical basis and technical guidance for the management and rehabilitation of water ecosystems. In the last four decades, dozens of evaluation methods have been applied to freshwater eutrophication, but there is a clear need to optimize and standardize the most suitable methods. We have addressed this gap by presenting a systematic review of methodologies. Due to the diversity and complexity of water bodies, no single evaluation method was identified that would adequately represent eutrophication under all scenarios. We demonstrate that lakes can best be assessed using the trophic level index (TLI) method, reservoirs and wetlands the trophic state index (TSI) and fuzzy comprehensive evaluation (FCE) method, respectively, and rivers the FCE method or back propagation (BP) neural network methods. More recently applied methodologies including spectral imaging and 3-D mapping of water quality using underwater gliders allow greater resolution and can be effective in managing waterbodies to avoid future eutrophication. The aim of this review is to guide future studies on the most appropriate methods available for assessing and reporting water eutrophication.
Impact of the Grid Resolution and Deterministic Interpolation of Precipitation on Rainfall-Runoff Modeling in a Sparsely Gauged Mountainous Catchment
Authors: Gilewski Paweł
Published: January 2021

Precipitation is a key variable in the hydrological cycle and essential input data in rainfall-runoff modeling. Rain gauge data are considered as one of the best data sources of precipitation but before further use, the data must be spatially interpolated. The process of interpolation is particularly challenging over mountainous areas due to complex orography and a usually sparse network of rain gauges. This paper investigates two deterministic interpolation methods (inverse distance weighting (IDW), and first-degree polynomial) and their impact on the outputs of semi-distributed rainfall-runoff modeling in a mountainous catchment. The performed analysis considers the aspect of interpolation grid size, which is often neglected in other than fully-distributed modeling. The impact of the inverse distance power (IDP) value in the IDW interpolation was also analyzed. It has been found that the best simulation results were obtained using a grid size smaller or equal to 750 m and the first-degree polynomial as an interpolation method. The results indicate that the IDP value in the IDW method has more impact on the simulation results than the grid size. Evaluation of the results was done using the Kling-Gupta efficiency (KGE), which is considered to be an alternative to the Nash-Sutcliffe efficiency (NSE). It was found that KGE generally tends to provide higher and less varied values than NSE which makes it less useful for the evaluation of the results.
Measuring Walkability with Street Connectivity and Physical Activity: A Case Study in Iran
Authors: Molaei Pouya , Tang Liyaning , Hardie Mary
Published: January 2021

The walkability of urban areas is an important criterion related to the level of physical activity and public health of citizens. This research aims to measure this parameter in Golsar town located in Rasht, Iran. Two methods were used in this research: Street connectivity and International Physical Activity Questionnaire (IPAQ). The principal variables of street connectivity were measured in four districts of Golsar by Geographic Information System (GIS) to rank each one. Then, the acquired results were compared by the average walking time of the respondents of the questionnaire. The comparison explicitly indicated that there is a strong positive correlation between the measures of street connectivity and people’s tendency to walk. As well, District 1 had the highest value of connectivity and the highest average time for walking amongst the four districts. This supports the contention that walkability and the level of outdoor physical activities of people in each district are undoubtedly under the influence of the variables of street connectivity. Nevertheless, the evaluation of other indexes such as proximity, land use mix, safety, and density in Golsar, in future research. can expand our perception of the walkability of this region.
Peneplains and tectonics in North-East Greenland after opening of the North-East Atlantic
Authors: Bonow Johan M. , Japsen Peter
Published: January 2021

Elevated plateaus with deeply incised valleys characterise elevated, passive continental margins (EPCMs) in all climate zones. These features are, however, a topic of debate regarding when and how the large-scale landscapes formed. We have investigated and mapped the partly glaciated landscape of North-East Greenland (70–78°N). The area consists of crystalline basement and Palaeozoic–Mesozoic rift basins, capped by Palaeogene basalts that erupted during the northeast Atlantic break-up. Our stratigraphic landscape analysis reveals a typical EPCM dominated by two elevated erosion surfaces, extending 200 km east–west and 900 km north–south. The low-relief Upper Planation Surface (UPS; c. 2 km above sea level) cuts across basement and Palaeogene basalts, indicating that it was graded to base level defined by the Atlantic Ocean in post-basalt times and subsequently uplifted. The UPS formed prior to the deposition of mid-Miocene lavas that rest on it, south of the study area. In the interior basement terrains, the Lower Planation Surface (LPS) forms fluvial valley benches at c. 1 km above sea level, incised below the UPS. The LPS is thus younger than the UPS, which implies that it formed post mid-Miocene. Towards the coast, the valley benches merge to form a coherent surface that defines flat-topped mountains. This shows that the LPS was graded to near sea level and was subsequently uplifted. Hence, both the UPS and the LPS formed as peneplains – erosion surfaces graded to base level. The fluvial valley benches associated with the LPS further indicates that full glacial conditions were only established after the uplift of the LPS in the early Pliocene (c. 5 Ma). The uplift of the LPS led to re-exposure of a Mesozoic etch surface. We conclude that episodes of late Neogene tectonic uplift shaped the stepped landscape and elevated topography in North-East Greenland.
Measuring Service Gap of Banking services in Bangladesh- A Study Based on Selected Private Commercial Bank in the Northern Region
Authors: Islam Tarannum , Sahiduj Jaman Shekh Md. , Lubna Tanzila Rahman
Published: January 2021

This research investigates the service gap between client’s expectation and perception regarding banking services in Bangladesh with a particular focus on the SERVQUAL model along with the five dimensions: Tangibility, Reliability, Responsiveness, Assurance, and Empathy. We investigate the dimensions of quality of banking service and its impact on customer satisfaction. A self-administered and structured questionnaire use to collect data from 200 respondents of banks’ clients. The SPSS software use here for analyzing data. Different statistical tools use which are compatible with our research, such as factor analysis, reliability analysis, and hypothesis testing. We survey twenty private commercial banks. Average of ten customers take as a sample from each bank. As for clients’ perception, the services gap (Expected service - Perceived service), in the dimensions of reliability, responsiveness, and empathy, is significant because expected service is below perceived service in the private banks in the northern region of Bangladesh.
Earnings inequality and the changing nature of work: Evidence from Labour Force Survey data of Bangladesh
Authors: Bidisha Sayema Haque , Mahmood Tanveer , Rahman Mahir A.
Published: January 2021

With structural changes in production coupled with technological progress, there have been shifts in modes of production and patterns of employment, with important consequences on task composition of occupations. This paper has utilized different rounds of Labour Force Survey data of Bangladesh and combined it with occupation network data of the United States along with its country-specific database and analysed the role of such factors on labour market outcomes. Our analysis shows a fall in the average routine intensity of tasks with no evidence of job polarization. We find a decline in earnings inequality where the decomposition analysis shows that earnings structure effect rather than characteristics effect plays a key role, with routine-task intensity of jobs and education explaining the majority of differences in earnings. Our analysis suggests that investing in education should be the highest priority, with greater emphasis on skill-biased training programmes, particularly those involving cognitive skill.
EFFECT OF CALCIUM, BORON AND MOLYBDENUM ON PLANT GROWTH AND BRACT PIGMENTATION IN POINSETTIA
Authors: Ayala-Arreola Juan , Castillo-González Ana Ma. , Valdez-Aguilar Luis A. , Colinas-León Ma. Teresa , Pineda-Pineda Joel , Avitia-García Edilberto
Published: January 2021

Foliar sprays of Ca (300, 400, and 500 mg L-1), B (0.2, 0.5, and 0.8 mg L-1), Mo (0.3, 0.4, and 0.5 mg L-1), Ca + B (400 + 0.5 mg L-1), Ca + Mo (400 + 0.4 mg L-1), B + Mo (0.5 + 0.4 mg L-1) and Ca + B + Mo (400 + 0.5 + 0.4 mg L-1), were applied to improve the quality of poinsettia plants (Euphorbia pulcherrima) cv. ‘Supjibi Red’. Treatments were applied three times at: beginning, middle, and end of the short photoperiod. Calcium at 400 mg L-1 increased significantly plant height by 15.3 %. Leaf chlorophyll concentration decreased by 25 % when bract pigmentation initiated. Treatments did not affect the leaf chlorophyll contents. Calcium (300 mg) and B (0.8 mg) increased the number of transitional bracts (5.7 and 5.6, respectively) compared to 0.4 mg L-1 Mo treatment; while B (0.5 mg) increased the total number of colored bracts per shoot (8.36) compared to the rest of the treatments. Total chlorophyll concentration decreased by 95 % in transitional bracts, carotenoids decreased 89 % and anthocyanins increased considerably (from 21.4 to 296.7 mg g-1). Foliar applications of calcium improved poinsettia plant height and the Ca plus B combination accelerated bract pigmentation.
ROTACIÓN ÓPTIMA EN PLANTACIONES DE EUCALIPTO AL INCLUIR INGRESOS POR CAPTURA DE CARBONO EN OAXACA, MÉXICO
Authors: Téllez-Mejía Eugenio , González-Guillén Manuel de Jesús , De los Santos-Posadas Héctor Manuel , Fierros-González Aurelio Manuel , Lilieholm Robert J. , Gómez-Guerrero Armando
Published: January 2021

Para aportar elementos que contribuyan a la toma de decisiones en una empresa forestal, este estudio examina la edad óptima de cosecha (turno o rotación óptima) en plantaciones de eucalipto (Eucalyptus grandis Hill ex Maiden y E. urophylla S. T. Blake) establecidas en el noreste de Oaxaca, México. Se determinó el valor neto presente y la rotación óptima para plantaciones en dos calidades de sitio y para dos escenarios de productos finales: 1) madera para celulosa; y 2) madera para aserrío más madera para celulosa, en ambos casos con y sin ingresos por captura de carbono. Se supusieron los costos de mantenimiento de la plantación con una tasa de descuento (r) de 4.5 %, un costo de establecimiento (Co) de $ 4123 ha-1, un precio de carbono (pc) de $ 31 (t CO2e)-1, un precio de madera sólida de $ 600 m-3 y un precio de madera para celulosa de $211 m-3. Se hizo un análisis de sensibilidad al incrementar r, Co y pc en intervalos de 2 %, $ 2000 ha-1 y $ 21 (t CO2e)-1, respectivamente. Las edades óptimas de cosecha encontradas con base únicamente en ingresos por venta de madera varían de 83 a 108 meses en el escenario 1, y de 108 a 163 meses en el escenario 2, según la especie y el índice de sitio. Al incorporar los beneficios por captura de carbono se obtuvo una extensión de la rotación. La edad óptima de cosecha se prolonga de 12 a 20 meses y de 17 a 30 meses para los dos escenarios, respectivamente. Los beneficios por captura de carbono incrementan el valor neto presente de la cosecha al extender la rotación al igual que la relación beneficio-costo, aunque los cambios en esta última son mínimos.
INDUCCIÓN DE PROEMBRIONES SOMÁTICOS EN AVE DEL PARAÍSO (Strelitzia reginae Banks)
Authors: Arzate-Fernández Amaury Martín , Piña-Escutia José Luis , Zavaleta-Mancera Hilda Araceli
Published: January 2021

El ave del paraíso (Strelitzia reginae Banks) es una planta ornamental que por su belleza es altamente cotizada como flor de corte. Se propaga por semilla y por división de matas, aunque ambos métodos son muy lentos. La multiplicación de plantas in vitro vía embriogénesis somática, ha sido exitosamente establecida en muchas especies ornamentales. Para S. reginae no existen reportes de su propagación mediante dicho proceso ya que presenta serios problemas de oscurecimiento de los explantes cultivados. En este trabajo se estableció un procedimiento para la inducción de proembriones somáticos (PES) a partir de fragmentos (explantes) del nudo cotiledonar de plántulas de 30 d de edad. A los cinco meses de incubación, los explantes cultivados en oscuridad produjeron PES en el medio Murashige y Skoog a 100 % y 50 % de su concentración, suplementado con 2,4-D (0.5 a 2.0 mg L-1), sacarosa (30 g L-1) y carbón activado (0.1 g L-1). Los PES crecieron y formaron estructuras de 5 a 6 mm de longitud, cuyo extremo distal presentó una organización celular comparable a la de un meristemo de raíz pero sin centro quiescente. Los cortes histológicos no evidenciaron la presencia de un meristemo apical de brote, lo cual pudo haber causado que los proembriones in vitro no completaran su desarrollo.
ADAPTACIÓN Y ESTABILIDAD DEL RENDIMIENTO EN GENOTIPOS DE FRIJOL AZUFRADO EN EL SUR DE SONORA, MÉXICO
Authors: Padilla-Valenzuela Isidoro , Salinas-Pérez Rafael A. , Acosta-Gallegos Jorge A. , Rodríguez-Cota Franklin G.
Published: January 2021

En Sonora, México se cultiva frijol (Phaseolus vulgaris L.) en 7600 ha de donde se obtienen 11 600 t, y se estima una demanda estatal de 50 000 t anuales. El frijol se siembra en dos épocas: otoñoinvierno y primavera-verano en el sur de Sonora en riego, y contribuye con 70 a 80 % de la superficie estatal. Las variedades predominantes son de grano grande (> 40 g/100 semillas) y de color amarillo que ocupan el 90 % del área. Las tres principales variedades son: ‘Azufrado Peruano 87’ (42 %), ‘Azufrado Pimono 78’ (27 %) y ‘Azufrado Higuera 94’ (13 %). Entre las limitantes importantes de la producción de frijol azufrado en la región destacan el mosaico común (BCMV), el mosaico sureño (BSMV), el mosaico clorótico (BClMV), el mosaico dorado (BGYMV) y el virus de la hoja enrollada de la calabaza (SLRMV), que pueden ocasionar la pérdida total de la producción. El propósito de esta investigación fue determinar la adaptación y estabilidad del rendimiento y variables relacionadas en cinco materiales de frijol azufrado. La investigación se condujo en el Valle del Mayo, Sonora, en suelo migajón limoso, durante los ciclos otoño-invierno 2002-2003, 2004-05, 2005-06 y 2006-07; las líneas avanzadas con hábito de determinado (Tipo I) fueron: Mo 94/95 1039 y Mo 94/95 1041, y los testigos comerciales ‘Azufrado Higuera 94’, ‘Azufrado Noroeste 94’ y ‘Azufrado Peruano 87’. Se analizó el rendimiento y sus componentes y la relación de la virosis con poblaciones de mosquita blanca (Bemisia argentifolii Bellows & Perring). Se usaron los valores de desviación estándar para estimar la consistencia de los genotipos, un modelo de estabilidad genotípica y una clasificación de variedades por estabilidad. Se encontró que la respuesta de las variedades es afectada por las bajas temperaturas y por la virosis asociada con grandes poblaciones de insectos vectores. En siembras de otoño-invierno bajo riego, el rendimiento depende del número y peso de la semilla y de los días a madurez fisiológica. El rendimiento más estable lo obtuvo la variedad ‘Azufrado Higuera 94’.
RENDIMIENTO Y CALIDAD NUTRIMENTAL DE FRIJOL EJOTERO (Phaseolus vulgaris L.) EN FECHAS DE SIEMBRA
Authors: Salinas-Ramírez Nicolás , Escalante-Estrada J. Alberto , Rodríguez-González Ma. Teresa , Sosa-Montes Eliseo
Published: January 2021

En México el consumo per capita de frijol ejotero (Phaseolus vulgaris L.) ha aumentado de 0.9 a 1.1 kg en los últimos años, por lo que se requiere incrementar su productividad y su calidad. Ello puede lograrse mediante prácticas agronómicas. La fecha de siembra es útil, para aprovechar al máximo las características del clima y que el cultivo exprese su potencial productivo. El presente estudio se realizó en Montecillo, Estado de México bajo condiciones de temporal o secano durante el ciclo primavera verano del 2005. Se utilizó el cv. de frijol ejotero ‘Hav-14’ de crecimiento indeterminado trepador, y el girasol (Helianthus annuus L.) cv. ‘Victoria’ como espaldera viva. Se determinó el rendimiento y la calidad nutricional del ejote producido en cinco fechas de siembra: 2 y 17 de mayo, 1 y 16 de junio, y 1 de julio. Las variables ambientales registradas fueron: temperaturas máxima y mínima, radiación fotosintéticamente activa, lluvia, evaporación y fotoperíodo. El mayor rendimiento (1170 g m-2) se obtuvo de la siembra del 2 de mayo y el menor (540 g m-2) en la del 1 de julio. El ejote fresco mostró los valores más altos en cenizas (9 %), fósforo (0.13 %), fibra detergente ácido (22 %), lignina (8.3 %), proteína (28.9 %) y grasa (0.88 %) en la siembra temprana del 2 mayo; en la siembra tardía del 1 de julio observaron los valores más altos en calcio (1.8 %), carbohidratos solubles (47 %), fibra detergente neutro (27.7 %), hemicelulosa (12.3 %) y materia orgánica (93.8 %). La conservación del ejote congelado y al vacío por seis meses no afectó su contenido de proteína.
EFECTO DE CITOCININAS EN LA PROPAGACIÓN in vitro DE AGAVES MEXICANOS
Authors: Domínguez-Rosales Manuel S. , Alpuche-Solís Ángel G. , Vasco-Méndez Nora L. , Pérez-Molphe-Balch Eugenio
Published: January 2021

La falta de sistemas eficientes de propagación es un factor que limita el aprovechamiento racional de varias especies de Agave, que en muchos casos han tenido una reducción peligrosa de sus poblaciones debido a la sobreexplotación de materiales silvestres. En este estudio se desarrollaron protocolos para la propagación in vitro de Agave cupreata, A. difformis, A. karwinskii, A. obscura y A. potatorum. Como explantes se utilizaron tejidos meristemáticos extraídos de plántulas germinadas in vitro. Se logró la formación de brotes múltiples en explantes basales en medio MS adicionado con 30 g L-1 de sacarosa, 8 g L-1 de agar y varios tratamientos con citocininas [6- bencilaminopurina (BA), 6-γ,γ-dimetilalilaminopurina (2iP), cinetina (Cin), tidiazurón (TDZ) y meta-topolina o N6-(metahidroxibencil) adenina (MT)]. Las eficiencias más altas en producción de brotes en A. cupreata y A. karwinskii se obtuvieron con 1.5 y 1 mg L-1 de BA, donde se generaron 10.5 y 6.1 brotes por explante, respectivamente. En A. difformis y A. obscura las mejores respuestas se obtuvieron con 0.2 mg L-1 TDZ con 8.5 y 11 brotes por explante, respectivamente. En A. potatorum la mejor respuesta ocurrió con 3 mg L-1 Cin, en el que se produjeron 6.9 brotes por explante. El enraizamiento de los brotes generados in vitro se alcanzó en medio MS basal con eficiencias entre 80 y 100 %, y la frecuencia de supervivencia de las plantas una vez transferidas a suelo fue de 72 % en promedio.
POLÍTICA DE PRECIOS DE GARANTÍA CONTRA APOYOS DIRECTOS: ANÁLISIS DEL BIENESTAR DEL PRODUCTOR
Authors: Jiménez-García Eligio , Martínez-Damián Miguel A. , Kido-Cruz Antonio
Published: January 2021

Hasta el año 1993 el gobierno Mexicano intervino en el mercado de granos básicos mediante precios de garantía. En 1994 el gobierno crea el Programa de Apoyos al Campo (PROCAMPO) que aplica apoyos directos al ingreso monetario de los productores y evita la distorsión en precios inherente a otros esquemas de subsidio o apoyos a la producción. En esta investigación se analizó el efecto de estos dos tipos de política sobre el bienestar del productor a través de la medición y la comparación del excedente del productor, definido como la cantidad de dinero que le da a ganar al productor una política económica por encima de sus costos de producción. Se encontró que aunque el cambio de política económica produjo una reducción del excedente del productor agrícola por la caída de precios de granos básicos, los apoyos otorgados por el PROCAMPO compensaron la pérdida de ingreso monetario. Al considerar una canasta de cultivos básicos que incluía maíz, frijol, trigo, arroz y sorgo, y suponer que el excedente del productor es una buena medida del bienestar del productor, el bienestar del productor no se redujo durante el periodo 1986-2004, debido a que los apoyos directos del PROCAMPO sobre-compensaron en tres veces la pérdida de ingreso causado por la reducción de precios.
POTENCIAL DE RENDIMIENTO DE POBLACIONES CRIOLLAS DE MAÍZ DE COAHUILA, MÉXICO
Authors: Nájera-Calvo Luis A. , Rincón-Sánchez Froylán , Ruiz-Torres Norma A. , Castillo-González Fernando
Published: January 2021

Las poblaciones y tipos de maíces (Zea mays L.) adaptados a condiciones de temporal o secano poseen atributos que pueden ser útiles en el mejoramiento genético. En el Estado de Coahuila, México, se ha identificado la presencia de siete grupos raciales. El objetivo del presente trabajo fue evaluar agronómicamente y determinar el potencial de rendimiento de grano de 90 poblaciones de maíces criollos recolectadas en el Estado de Coahuila. La evaluación agronómica se hizo en 2008 y 2009, en dos localidades: El Mezquite, Galeana, Nuevo León (1890 m) y General Cepeda, Coahuila (1350 m). La combinación de años y localidades fue considerada como cuatro ambientes (MEZ08, MEZ09, GC08 y GC09). Las poblaciones fueron agrupadas de acuerdo con la altitud de procedencia en: bajas (0 a 1000 m), intermedias (1001 a 1800 m), transición (1801 a 2000 m) y de altura (más de 2000 m). Los resultados mostraron diferencias (P ≤ 0.01) entre grupos y en la interacción grupos x ambientes, para floración masculina y rendimiento de grano; también se encontraron diferencias (P ≤ 0.01) entre poblaciones dentro de grupos y en poblaciones dentro de grupo x ambientes. El análisis de la interacción poblaciones x ambientes permitió identificar tres grupos según su adaptación a las localidades: el primero, con adaptación a El Mezquite (33.3 %), el segundo a General Cepeda (42.2 %), y el tercer grupo (24.4 %) con estabilidad a través de ambientes. Las poblaciones 19, 22, 34 y 61 tuvieron adaptación a El Mezquite; las poblaciones 74,76 y 88 a General Cepeda; y las poblaciones 35, 37, 38, 64, 66 y 81 mostraron estabilidad a través de ambientes. Los grupos raciales con mayor potencial de rendimiento fueron Tuxpeño, Tuxpeño Norteño y Ratón.
CALIDAD DE GRANO Y DE TORTILLAS DE MAÍCES CRIOLLOS DEL ALTIPLANO Y VALLE DEL MEZQUITAL, MÉXICO
Authors: Vázquez-Carrillo Ma. Gricelda , Pérez-Camarillo Juan P. , Hernández-Casillas Juan M. , Marrufo-Díaz Ma. de la Luz , Martínez-Ruiz Elisa
Published: January 2021

En el Estado de Hidalgo, México, se establecen alrededor de 200 mil hectáreas de maíz (Zea mays L.) bajo condiciones de temporal o secano, 95 % corresponde a maíces criollos. Los objetivos de esta investigación fueron determinar la calidad del grano y tortilla de 26 maíces criollos del Altiplano y Valle del Mezquital, Hidalgo, México, e identificar las razas sobresalientes para la industria de la masa y la tortilla. Dichas accesiones incluían las razas Elotes Cónicos, Chalqueño, Cónico, Tuxpeño, Arrocillo, Celaya, Tabloncillo, Ratón, Pepitilla, Cacahuacintle, Palomero Toluqueño, Olotillo, Elotes Occidentales, Cónico Norteño y Bolita. El análisis de varianza mostró diferencia significativa (P ≤ 0.05) en todas las variables analizadas. Las razas preferidas por los productores fueron Cónico (32 %), Chalqueño (20 %) y Elotes Cónicos (18 %). Los maíces presentaron una variedad de colores (negros, rojos, amarillos, anaranjados pintos y blancos), de tamaños (grande, mediano y pequeño) y de texturas (muy suave, suave, intermedio y duro), así como altos porcentajes de pedicelo y pericarpio y bajas proporciones de germen. Algunas de estas variables limitan su procesamiento en los molinos de masa-tortilla. Con las razas Cónico, Chalqueño, Tuxpeño, Cónico Norteño, Olotillo, Pepitilla y Celaya de grano blanco y textura suave e intermedia, se produjeron las tortillas de mejor calidad, con mayor: humedad (40.3 %), relación masa/grano (2.0:1.1) y tortillas/grano (1.4:1.1) y requirieron poca fuerza para romperse (suaves) después de haber sido elaboradas (< 180 gf), la fuerza se incremento significativamente (P < 0.05), 24 horas después del almacenamiento a 4 °C ( x = 191.4 gf). Asimismo, se encontró que eran de apariencia luminosa (L* = 71.8 %), sin observar cambios durante su almacenamiento (71.5 %).
APTITUD COMBINATORIA GENERAL Y ESPECÍFICA DEL CONTENIDO DE AZÚCARES EN MAÍCES CRIOLLOS ELOTEROS
Authors: Coutiño-Estrada Bulmaro , Vidal-Martínez Víctor A. , Cruz-Gómez Bertha , Cruz-Vázquez Carolina
Published: January 2021

Seis variedades criollas de maíz, sobresalientes por sus cualidades eloteras y sus 15 cruzas directas se evaluaron en dos localidades de Chiapas con objeto de conocer la aptitud combinatoria general y la específica del contenido de azúcares medida en °Brix, así como la heterosis manifestada en las cruzas. Se encontró que sólo los efectos génicos aditivos fueron significativos (P ≤ 0.05), lo que indica que esta característica elotera puede ser mejorada en las variedades criollas de mayores efectos de aptitud combinatoria general mediante el uso de esquemas de selección recurrente para explotar la varianza aditiva presente. Las variedades progenitoras ‘Campechano’ y ‘Paloma’ tuvieron los mayores efectos de ACG (0.781 y 0.381), al producir los elotes más dulces con 13.1 y 12.9 °Brix, respectivamente. Las cruzas tuvieron valores bajos de heterosis.
BASES MORFOLÓGICAS DE CÓMO PUDO HABERSE ORIGINADO EL DIMORFISMO SEXUAL EN EL PASTO BÚFALO
Authors: Martínez-Reyna Juan M. , Armendáriz-Erives Sigifredo
Published: January 2021

El dimorfismo sexual es una característica del zacate Búfalo [Buchloe dactyloides (Nutt.) Engelm. Sin. Bouteloua dactyloides Columbus], especie dioica nativa de Norteamérica con potencial para ser usada como césped en México. Sus inflorescencias son tan diferentes que en un principio las plantas femeninas fueron clasificadas como especie diferente de las plantas masculinas. En este estudio se describen los cambios morfológicos que pudieron haberse presentado en una inflorescencia hermafrodita de un presunto ancestro, para luego dar origen al dimorfismo sexual que hoy presenta B. dactyloides. Para ello se hicieron estudios descriptivos de las diferencias en la morfología floral dentro de las mismas inflorescencias y entre las inflorescencias de dos híbridos inter-ploidales trimonoicos y sus progenitores dioicos. Con base en estas evidencias morfológicas aquí se postulan los eventos que pudieron haber originado el dimorfismo sexual. Para transformarse en la inflorescencia femenina actual, la inflorescencia hermafrodita ancestral tuvo que sufrir los siguientes cambios: reducción del número de espiguillas por ramificación espigada; reducción del espacio entre dichas ramificaciones; alargamiento de las segundas glumas para cubrir totalmente las florecillas; prolongación de las nervaduras central y de las dos laterales para formar los tres ápices dentados que coronan el involucro y aparición de pubescencia en estas glumas; reducción de las primeras glumas; ensanchamiento de las segundas glumas para envolver la florecilla en su totalidad; esterilización masculina de la florecilla hermafrodita; y endurecimiento de las glumas. En cambio, la inflorescencia masculina no debió pasar por grandes transformaciones, ya que morfológicamente es muy similar a las inflorescencias de especies hermafroditas del género Bouteloua con las que esta especie está emparentada.