scholarly journals The Mesoamerican mid-summer drought: the impact of its definition on occurrences and recent changes

2021 ◽  
Author(s):  
Edwin P. Maurer ◽  
Iris T. Stewart ◽  
Kenneth Joseph ◽  
Hugo G. Hidalgo
Keyword(s):  
Historical Record ◽  
Climate Projections ◽  
Summer Drought ◽  
Seasonal Forecasts ◽  
Drought Pattern ◽  
The Caribbean ◽  
The Impact ◽  
Minimum Intensity ◽  
Selection Of

Abstract. The mid-summer drought, veranillo or canícula, is a phenomenon experienced in many areas, including Mexico, Central America, and the Caribbean. It generally is experienced as reduced rainfall in July–August, in the middle of the typical rainy season (May–September). Many past studies have attempted to quantify changes in mid-summer drought characteristics during the recent past or for future climate projections. To do this, objective definitions of a mid-summer drought’s occurrence, strength and duration have been developed by many researchers. In this effort we adopt a recent set of definitions and examine the impact of varying these on the characterization of mid-summer droughts and the detected changes over the past four decades. We find the selection of a minimum intensity threshold has a dramatic effect on the results of both the area considered as experiencing a mid-summer drought and the changes detected in the recent historical record. The intensity chosen can affect both the magnitude and direction of changes reported in the recent observed record. Further, we find that the typical mid-summer drought pattern may not be occurring during the time it has historically; whether examining past or future changes or developing improved seasonal forecasts, the non-stationarity of its timing should be accommodated.

scholarly journals Characterization of Carrier Phase-Based Positioning in Real-World Jamming Conditions

2021 ◽  
Vol 13 (14) ◽  
pp. 2680
Author(s):  
Søren Skaarup Larsen ◽  
Anna B. O. Jensen ◽  
Daniel H. Olesen
Keyword(s):  
Real World ◽  
Carrier Phase ◽  
Reference Station ◽  
Baseline Length ◽  
Dual Frequency ◽  
Positioning Accuracy ◽  
The Impact ◽  
Single Versus ◽  
Selection Of

GNSS signals arriving at receivers at the surface of the Earth are weak and easily susceptible to interference and jamming. In this paper, the impact of jamming on the reference station in carrier phase-based relative baseline solutions is examined. Several scenarios are investigated in order to assess the robustness of carrier phase-based positioning towards jamming. Among others, these scenarios include a varying baseline length, the use of single- versus dual-frequency observations, and the inclusion of the Galileo and GLONASS constellations to a GPS only solution. The investigations are based on observations recorded at physical reference stations in the Danish TAPAS network during actual jamming incidents, in order to realistically evaluate the impact of real-world jamming on carrier phase-based positioning accuracy. The analyses performed show that, while there are benefits of using observations from several frequencies and constellations in positioning solutions, special care must be taken in solution processing. The selection of which GNSS constellations and observations to include, as well as when they are included, is essential, as blindly adding more jamming-affected observations may lead to worse positioning accuracy.

scholarly journals Characterization of the impact on the society of the local cisco networking academy of ITSA in Barranquilla

2020 ◽  
Vol 4 (1) ◽  
pp. 21-34
Author(s):  
Leonel Hernandez ◽  
Piedad Marchena ◽  
Aji Prasetya Wibawa
Keyword(s):  
Caribbean Region ◽  
Local Society ◽  
The Caribbean ◽  
New Challenges ◽  
The University ◽  
The Impact ◽  
The City ◽  
A Company ◽  
Day By Day

By 1997, Cisco Systems, a company already consolidated in the technology and communications market, saw the need to train personnel who had the skills to configure, manage, install and support all its products in general at all levels, from design to the implementation of solutions. In Colombia, more precisely in the city of Barranquilla, the ITSA University Institution in the early 2000s saw an excellent opportunity to ally with the University created by Cisco, called Cisco Networking Academy, to train professionals in the Caribbean region capable of face the new challenges that technology in networks is generating day by day, becoming in the first Institution of higher education in the region to provide this type of training with international certification and endorsement. From then on, the local Cisco academy has strengthened and significantly impacted local society, generating valued and skilled labor in the labor market of the city and the region. The purpose of this work is to measure this impact, focused on the Cisco, CCNA, and CCNP flagship courses between 2015 and 2019, verifying how ITSA, through the Cisco Academy, has transformed lives. The research methodology is descriptive, exploratory, and documentary

scholarly journals Caracterización del “veranillo” en dos cuencas de la vertiente del Pacífico de Costa Rica, América Central

2015 ◽  
Vol 62 (4) ◽  
pp. 1 ◽  
Author(s):  
Eric J. Alfaro
Keyword(s):  
Costa Rica ◽  
Summer Drought ◽  
Trade Winds ◽  
Monthly Data ◽  
Tropical Regions ◽  
The Pacific ◽  
Low Level Jet ◽  
The Caribbean ◽  
Pacific Slope

<p>The Eastern Tropical Pacific region is characterized by climate features rarely observed in tropical regions, one of them is the Mid-Summer Drought (MSD), “veranillo” or “canícula” in Spanish. On the Pacific slope of Central America, the annual precipitation cycle is characterized by two rainfall maxima in June and September-October, an extended dry season from November to May, and a shorter reduced precipitation period during July–August (MSD), during July, the magnitude of the trade winds increases and this is associated also with the Caribbean Low Level Jet (CLLJ), but characterization of these features using monthly data is difficult. In this work, seven daily gauge stations records, located at two important river basins of Costa Rica, Tarcoles and Tempisque, were studied to characterize the MSD from 1937 to 2012. Among the aspects considered are the MSD Start, Timing, End, Duration, Intensity and Magnitude. The modulation and seasonal predictability of these aspects by climate variability sources as Equatorial Eastern Pacific was lately explored, showing that warmer (cooler) conditions in Niño 3.4 tend to be associated to drier (wetter) MSD events. Rev. Biol. Trop. 62 (Suppl. 4): 1-15. Epub 2014 Diciembre 01.</p><div> </div>

scholarly journals On the Use of Parametric Wind Models for Wind Wave Modeling under Tropical Cyclones

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2044 ◽  
Author(s):  
Pablo Ruiz-Salcines ◽  
Paulo Salles ◽  
Lucia Robles-Díaz ◽  
Gabriel Díaz-Hernández ◽  
Alec Torres-Freyermuth ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Ocean Waves ◽  
Parametric Models ◽  
Design Parameters ◽  
Wind Fields ◽  
Tropical Areas ◽  
The Caribbean ◽  
Wave Models ◽  
Selection Of

Wave and wind forces from tropical cyclones are one of the main design parameters of coastal and offshore infrastructure in tropical areas. The estimation of ocean waves parameters in the design of structures in tropical areas is difficult due to the complexity of wind fields associated with tropical cyclones. The use of numerical wave models, forced with parametric wind fields, is a common practice within the climatic characterization of extreme events. However, there is currently no consensus on the selection of parametric models for wave prediction due to the lack of a rigorous assessment of different models. In this study, six well-known parametric wind models were tested, compared, and applied in the Gulf of Mexico and the Caribbean Sea. Therefore, the evaluation and comparison of the resulting wind and wave fields are presented, showing that a particular model may best represent a specific event, but, when dealing with a large number of events, the choice of a particular parametric wind model or a combination of them does not guarantee greater accuracy.

Calibrator material selection: a key criteria during biomarker assay method development

Bioanalysis ◽  
2021 ◽  
Author(s):  
Sai P Thankamony ◽  
Rong Liu ◽  
Jon E Peterson ◽  
Rasa Santockyte ◽  
Timothy Olah ◽  
...  
Keyword(s):  
Decision Making ◽  
Case Studies ◽  
Method Development ◽  
Material Selection ◽  
Assay Method ◽  
Context Of Use ◽  
The Impact ◽  
Selection Of

Biomarker assay method development is a multistep rigorous process and calibrant material selection is integral to ensuring the quality of such assays. However, the impact of selection of calibrator material may often get overlooked. In this article, we highlight three case studies where biomarker calibrant material selection was deemed an essential criterion for consideration. Through these case studies we highlight challenges faced, steps taken and discuss the impact on assay-related decision-making. We also provide additional perspectives for selection and characterization of calibrant proteins in the setting of an evolving biomarker context of use.

scholarly journals Impact of Model Resolution on the Prediction of Summer Precipitation over the United States and Mexico

2005 ◽  
Vol 18 (18) ◽  
pp. 3910-3927 ◽  
Author(s):  
Kingtse C. Mo ◽  
Jae-Kyung Schemm ◽  
H. M. H. Juang ◽  
R. Wayne Higgins ◽  
Yucheng Song
Keyword(s):  
Gulf Of California ◽  
The United States ◽  
Global Model ◽  
Summer Drought ◽  
Interannual Variations ◽  
Monsoon Precipitation ◽  
Seasonal Forecasts ◽  
Low Level ◽  
Low Level Jet ◽  
The Impact

Abstract Summer seasonal simulations for selected years were performed using the NCEP Global Forecast System (GFS) at high (T126L28) and low (T62L28) resolutions, and the NCEP 80-km regional spectral model (RSM) nested in the T62 model outputs (RSM80/T62). All models have 28 levels in the vertical. All experiments were performed with prescribed observed sea surface temperatures to ensure that simulation errors came from model deficiencies. While the T126L28 model does not have a statistically significant advantage in simulating 500-hPa height anomalies over the Pacific–North American domain, it yields better monsoon precipitation forecasts and interannual variability. The T62L28 model simulations are too dry over the Southwest and northwestern Mexico when compared to observations and do not properly capture interannual variations of monsoon rainfall. The RSM80/T62 nesting improves the overall rainfall simulations somewhat but is not able to overcome deficiencies of the T62L28 global model to capture interannual variations in monsoon precipitation. Results indicate that a high-resolution version of the global model is needed for seasonal forecasts of monsoon precipitation. Both models capture the low-level jet from the Great Plains (GPLLJ) and rainfall anomalies associated with the 1993 summer floods and the 1988 summer drought, although the simulated rainfall maxima are often weaker and shifted spatially when compared to observations. The impact of horizontal resolution is largely local and is limited to areas over the western region of North America. The T126 model is able to capture the low-level jet from the Gulf of California (GCLLJ), while the T62 model is too coarse to resolve the Gulf of California (GOC). Moisture surges along the GOC are not properly simulated by the T62 model. Overall, the T62 model simulates a very dry Southwest and a weaker monsoon.

Virologic Aspects of Mucosal Transmission

2019 ◽  
Vol 15 (1) ◽  
pp. 14-27
Author(s):  
Zachary Ende ◽  
Martin J. Deymier ◽  
Eric Hunter
Keyword(s):  
Infected Individual ◽  
Genetic Bottleneck ◽  
Viral Quasispecies ◽  
Biological Characterization ◽  
Mucosal Transmission ◽  
Effective Interventions ◽  
Stochastic Events ◽  
The Impact ◽  
Selection Of

The transmission of HIV is generally inefficient. Despite the development of a diverse viral quasispecies in a chronically infected individual, a severe genetic bottleneck is observed during transmission, leading to only one or a few genetic variants establishing infection. This genetic bottleneck is the result of both stochastic events and selection pressures, such that viruses with specific traits are favored during transmission. This chapter discusses current models of HIV mucosal transmission, evidence for selection of specific viral traits during this process, and the biological characterization of transmitted founder viruses based on monkey models and human cohorts. The impact of transmitted viral phenotypes on disease progression is also described. Understanding in greater depth the key viral features required for transmission will be essential to the development of effective interventions for HIV prevention.

scholarly journals Mechanical Properties of Thermoplastics Corn Starch (TPCS) Reinforced Pineapple Leaf Fibre (PALF) Composite

2019 ◽  
Vol 8 (4) ◽  
pp. 8817-8821
Keyword(s):  
Corn Starch ◽  
Tensile Modulus ◽  
Impact Testing ◽  
Compression Moulding ◽  
Weight Percentage ◽  
Flexural Testing ◽  
The Impact ◽  
Fibre Loading ◽  
Selection Of

The aim of this study is to investigate the mechanical characterization of bio-composites on thermoplastic corn starch (TPCS) reinforced with 2 mm length of pineapple leaf fibre (PALF). The selection of different weight percentages of fibres (20, 30, 40, 50 and 60) weight percentage (wt.%) of PALF contents were applied in this study. The mixtures of TPCS with different wt.% of PALF were made by using a hot compression moulding at 165 °C for 15 minutes. The mechanical testing that has been performed are tensile, flexural and impact testing to determine the effect of fibre loading on bio-composites characteristics. The results show that by incorporating 40 wt.% loading of PALF, the tensile strength and tensile modulus has increased to the maximum. However, the flexural testing result shows that 50 wt.% loading of PALF show the highest strength and modulus. Meanwhile, the impact testing result shows decrement when the loadings of PALF increases. Scanning electron microscopy (SEM) show that the TPCS with 40 wt.% of PALF have a good miscibility between matrix/fibre in the bio-composites. Overall, the TPCS/PALF composites enhance the properties of the bio-composites for short-life application: that is, plate, container, disposable tray, packaging etc.

scholarly journals The Impact of Drought Stress on the Height Growth of Young Norway Spruce Full-Sib and Half-Sib Clonal Trials in Sweden and Finland

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 498
Author(s):  
Haleh Hayatgheibi ◽  
Matti Haapanen ◽  
Jenny Lundströmer ◽  
Mats Berlin ◽  
Katri Kärkkäinen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Additive Genetic Variance ◽  
Height Growth ◽  
Severe Drought ◽  
Summer Drought ◽  
Good Growth ◽  
Genotype By Environment ◽  
Genetic And Phenotypic Correlations ◽  
The Impact ◽  
Selection Of

The summer drought of 2018 was one of the most climatically severe events in Europe that led to record-breaking temperatures and wildfires in many parts of Europe. The main objective of this study was to assess the impact of the 2018 drought on the phenotypic and genetic response of Norway spruce height growth using the Standardized Precipitation-Evapotranspiration Index (SPEI). To achieve this, the total cumulative height growth of about 6000 clones from 2016 to 2019 in four full-sib trials in Sweden, aged 6–7 years, and from 2017 to 2019 in two half-sib trials in Finland, aged 8–9 years, were measured. The results indicate that the 2018 drought caused reductions in the increment of trees. Although heritability estimates were similar to other reports for Norway spruce, the additive genetic variance was highly inflated in one of the visibly drought-damaged trials in Southern Sweden. Similarly, the genotype by environment (G × E) interaction was highly significant in the drought-damaged Southern Swedish trials. Both additive genetic and phenotypic correlations obtained between height increments in 2019 and final heights were the weakest in all studied trials, implying that the drought legacies might have influenced the recovery of trees in 2019. We may conclude that the severe drought can be an underlying factor for a strong G × E interaction and changes in the ranking of genotypes. Therefore, a selection of drought-resistant genotypes with a good growth capacity tested in variables sites should be considered as an important criterion for future breeding of Norway spruce.

scholarly journals Transcriptomic and metabolomic characterization of post-hatch metabolic reprogramming during hepatic development in the chicken

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Heidi A. Van Every ◽  
Carl J. Schmidt
Keyword(s):  
Artificial Selection ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Metabolic Reprogramming ◽  
Liver Growth ◽  
Major Organ ◽  
Hepatic Development ◽  
The Impact ◽  
Selection Of

Abstract Background Artificial selection of modern meat-producing chickens (broilers) for production characteristics has led to dramatic changes in phenotype, yet the impact of this selection on metabolic and molecular mechanisms is poorly understood. The first 3 weeks post-hatch represent a critical period of adjustment, during which the yolk lipid is depleted and the bird transitions to reliance on a carbohydrate-rich diet. As the liver is the major organ involved in macronutrient metabolism and nutrient allocatytion, a combined transcriptomics and metabolomics approach has been used to evaluate hepatic metabolic reprogramming between Day 4 (D4) and Day 20 (D20) post-hatch. Results Many transcripts and metabolites involved in metabolic pathways differed in their abundance between D4 and D20, representing different stages of metabolism that are enhanced or diminished. For example, at D20 the first stage of glycolysis that utilizes ATP to store or release glucose is enhanced, while at D4, the ATP-generating phase is enhanced to provide energy for rapid cellular proliferation at this time point. This work has also identified several metabolites, including citrate, phosphoenolpyruvate, and glycerol, that appear to play pivotal roles in this reprogramming. Conclusions At Day 4, metabolic flexibility allows for efficiency to meet the demands of rapid liver growth under oxygen-limiting conditions. At Day 20, the liver’s metabolism has shifted to process a carbohydrate-rich diet that supports the rapid overall growth of the modern broiler. Characterizing these metabolic changes associated with normal post-hatch hepatic development has generated testable hypotheses about the involvement of specific genes and metabolites, clarified the importance of hypoxia to rapid organ growth, and contributed to our understanding of the molecular changes affected by decades of artificial selection.

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