scholarly journals Can environmental variation affect seedling survival of plants in northeastern Mexico?

2011 ◽  
Vol 63 (3) ◽  
pp. 731-737 ◽  
Author(s):  
Jaime García
Keyword(s):  
Native Species ◽  
Early Stage ◽  
Seedling Survival ◽  
Limiting Factors ◽  
Rainfall Events ◽  
Two Factors ◽  
Celtis Pallida ◽  
Northeastern Mexico ◽  
Biological Aspects ◽  
Climate Events

The effects of global warming increase the frequency and intensity of many climate events such as rainfall. We evaluated the effects of environmental conditions on early stage seedling survival of the native thorn scrub species Caesalpinia mexicana A. Gray, Celtis pallida Torr., Cordia boissieri A. DC., and Ebenopsis ebano (Berland.) Barneby and J.W. Grimes, during the summer of 2009 and 2010. The experimental design had two factors, two levels of rainfall and three microhabitats of thorn scrub: (i) open interspace, (ii) thorn scrub edge and (iii) under the canopy of dense thorn scrub. In dense thorn scrub, seedling survival was higher for Caesalpinia mexicana and Celtis pallida, and for Cordia boissieri and Ebenopsis ebano seedling survival was higher in dense thorn scrub and thorn scrub edge. The effect of rainfall on seedling survival depended on the year. Rainfall in 2010 and dense thorn scrub increased seedling survival of native species. For survival, the limiting factors of microhabitats appear to change across the years. Besides rainfall events, biological aspects like competition and mycorrhiza effects would need to be considered in models of plant establishment.

scholarly journals Wood Volume Production and Use of 10 Woody Species in Semiarid Zones of Northeastern Mexico

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Rahim Foroughbakhch ◽  
Artemio Carrillo Parra ◽  
Jorge Luis Hernández Piñero ◽  
Marco Antonio Alvarado Vázquez ◽  
Alejandra Rocha Estrada ◽  
...  
Keyword(s):  
Native Species ◽  
Growth Parameters ◽  
Eucalyptus Camaldulensis ◽  
Woody Species ◽  
Research Strategy ◽  
Wood Volume ◽  
Rural Villages ◽  
Acacia Farnesiana ◽  
Volume Production ◽  
Northeastern Mexico

A research strategy was established to analyze the structure of timber trees in terms of forest productivity (volume and wood density) of 10 species. The native speciesAcacia farnesiana, Acacia schaffneri,Bumelia celastrina,Cercidium macrun,Condalia hookeri,Ebenopsis ebano,Helietta parvifolia, andProsopis laevigataand the exotic speciesEucalyptus camaldulensisandLeucaena leucocephalawere chosen due to their ecological and economic importance to the rural villages of northeastern Mexico. Measurements of different growth parameters and volume of trees were evaluated. The introduced speciesE. camaldulensisandL. leucocephalashowed the best performance in wood volume production per tree and per hectare when compared to the native species. Likewise, among the native species,E. ebano,P. laevigata,C. hookeri, andA. farnesianatended to show better characteristics in terms of wood volume production in comparison toH. parvifolia,A. schaffneri,C. macrum, andB. celastrina. Results showed a high diversity on the properties studied. The high biomass produced by most of the species considered in this study revealed their great energetic potential when used as wood and firewood or vegetal charcoal.

scholarly journals Growth Response of Seedlings of Four Robusta Coffee (Coffea canephora Pierre. Ex. A. Froehner) Clones to Drought Stress

2019 ◽  
Vol 35 (1) ◽  
pp. 1-11
Author(s):  
Novie Pranata Erdiansyah ◽  
Ade Wachjar ◽  
Eko Sulistyono ◽  
Supijatno Supijatno
Keyword(s):  
Drought Stress ◽  
Block Design ◽  
Free Water ◽  
Coffea Canephora ◽  
Growth And Yield ◽  
Limiting Factors ◽  
Coffee Plantations ◽  
Robusta Coffee ◽  
Randomized Block Design ◽  
Two Factors

Drought is one of the limiting factors for the growth and yield of coffee plants. Drought due to long dry season has caused many losses for coffee plantations. This study aimed to evaluate the response of four Robusta coffee clones to drought stress at seedling stage and determine the best clone with high tolerance to drought. The study was conducted in Indonesian Coffee and Cocoa Reseach Institute (ICCRI) Jember, East Java in November 2018–Mei 2019. The experimental design used a Randomized Block Design (RCBD) with two factors. The first factor has consisted of five levels drought through providing volume watering based coefficient and evaporation value of free water surface (Eo), namely: 0.5 Eo; 1.0 Eo; 1.5 Eo; 2.0 Eo; 2.5 Eo (control). The second factor has consisted of four Robusta coffee clones, namely: BP 409 (drought tolerant clone); BP 308; BP 939 and BP 358 (vulnerable to drought stres). The result showed that reduction in the volume of watering from 2.5 Eo until 0.5 Eo causes drought, reduce coffee growth linearly. Clone BP 409 and BP 939 had better tolerance of drought stress compared with BP 308 and BP 358. The anatomical adaptation of leaves of BP 409 to drought stress was by thickening of wax layer and palisade tissue. BP 939 thickened its leaves due to drought stress as a mechanism of adaptation to such condition.

scholarly journals Revisiting early-stage COVID-19 strategy options

F1000Research ◽  
2021 ◽  
Vol 9 ◽  
pp. 327
Author(s):  
Philip Machanick
Keyword(s):  
Early Stage ◽  
Asymptomatic Infection ◽  
Interesting Case ◽  
Precise Analysis ◽  
Two Factors ◽  
The Difference ◽  
Nonpharmaceutical Interventions ◽  
Shed Light ◽  
Roll Out

Background: Early-stage interventions in a potential pandemic are important to understand as they can make the difference between runaway exponential growth that is hard to turn back and stopping the spread before it gets that far. COVID19 is an interesting case study because there have been very different outcomes in different localities. These variations are best studied after the fact if precision is the goal; while a pandemic is still unfolding less precise analysis is of value in attempting to guide localities to learn lessons of those that preceded them. Methods: I examine two factors that could differentiate strategy: asymptomatic spread and the risks of basing strategy on untested claims, such as potential protective value of the Bacillus Calmette-Guerin (BCG) tuberculosis vaccine. Results: Differences in disease progression as well as the possibility of alternative strategies to prevent COVID-19 from entering the runaway phase or damping it down later can be elucidated by a study of asymptomatic infection. An early study to demonstrate not only what fraction are asymptomatic but how contagious they are would have informed policy on nonpharmaceutical interventions but could still be of value to understand containment during vaccine roll out. Conclusions: When a COVID-19 outbreak is at a level that makes accurate trace-and test possible, investigation of asymptomatic transmission is viable and should be attempted to enhance understanding of spread and variability in the disease as well as policy options for slowing the spread. Understanding mild cases could shed light on the disease in the longer term, including whether vaccines prevent contagiousness.

scholarly journals Revisiting Early-stage COVID-19 Strategy Options

2020 ◽  
Author(s):  
Philip Machanick
Keyword(s):  
Exponential Growth ◽  
Early Stage ◽  
Interesting Case ◽  
Bacillus Calmette Guerin ◽  
Alternative Strategies ◽  
Early Stages ◽  
Precise Analysis ◽  
Two Factors ◽  
The Difference

Early-stage interventions in a potential pandemic are important to understand as they can make the difference between runaway exponential growth that is hard to turn back and stopping the spread before it gets that far. COVID-9 is an interesting case study because there have been very different outcomes in different localities. These variations are best studied after the fact if precision is the goal; while a pandemic is still unfolding less precise analysis is of value in attempting to guide localities in the early stages to learn lessons of those that preceded them. I examine two factors that could differentiate strategy: asymptomatic spread and differences in use of the Bacillus Calmette-Guerin (BCG) tuberculosis vaccine. These differences point to the possibility of alternative strategies to prevent COVID-19 from entering the runaway phase. The most promising is testing all contacts of anyone who has tested positive, not only those who are symptomatic. Should this demonstrate asymptomatic transmission, then all contacts of anyone who tests positive should be isolated and tested, and only released from quarantine when it is clear that they are past incubation and not positive.

scholarly journals Development of Korean Nomograms for Forecasting and Alerting Debris Flows Based on Critical Accumulated Rainfall

2019 ◽  
Author(s):  
Dong-Ho Nam ◽  
Suk-Ho Lee ◽  
Byung-Sik Kim
Keyword(s):  
South Korea ◽  
Urban Areas ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Short Term ◽  
Rainfall Events ◽  
Accumulated Rainfall ◽  
Landslides And Debris Flows ◽  
Climate Events ◽  
Heavy Rains

Ongoing climate change causes abnormal climate events worldwide such as increasing temperatures and changing rainfall patterns. With South Korea facing growing damage from the increased frequency of localized heavy rains, the country is not an exception. In particular, its steep slope lands, including mountainous areas, are vulnerable to damage from landslides and debris flows. In addition, localized short-term heavy rains that occur in urban areas with extremely high intensity tend to lead a sharp increase in damage from soil-related disasters and cause huge losses of life and property. Currently, South Korea predicts landslides and debris flows using the standards for forecasting landslides and heavy rains. However, as the forecasting is conducted separately for rainfall intensity and accumulated rainfall, this lacks a technique that reflects both amount and intensity of rainfall in an episode of localized heavy rainfall. This study, therefore, aims to develop such a technique by collecting past cases of debris flow occurrences and rainfall events that accompanied debris flows to calculate the rainfall triggering index (RTI) reflecting accumulated rainfall and rainfall intensity. In addition, the RTI is converted into the critical accumulated rainfall (Rc) to use precipitation information and provide real-time forecasting. The study classifies the standards for flow debris forecasting into three levels: ALERT (10%–50%), WARNING (50%–70%), and EMERGENCY (70% or higher), to provide a nomogram for 6 hr, 12 hr, and 24 hr. As a result of applying this classification into the actual cases of Seoul, Chuncheon, and Cheongju, it is found that about 2–4 hr of response time is secured from the point of the Emergency level to the occurrence of debris flows.

scholarly journals An Adaptive Bayesian Melding Method for Reliability Evaluation Via Limited Failure Data: An Application to the Servo Turret

2020 ◽  
Vol 10 (21) ◽  
pp. 7591
Author(s):  
Bo Sun ◽  
Zhaojun Yang ◽  
Narayanaswamy Balakrishnan ◽  
Chuanhai Chen ◽  
Hailong Tian ◽  
...  
Keyword(s):  
Early Stage ◽  
Reliability Evaluation ◽  
Limiting Factors ◽  
Computationally Efficient ◽  
Expert Opinions ◽  
Failure Data ◽  
Importance Resampling ◽  
The Individual ◽  
Short Time ◽  
Logic Inference

In the early stage of product development, reliability evaluation is an indispensable step before launching a product onto the market. It is not realistic to evaluate the reliability of a new product by a host of reliability tests due to the limiting factors of time and test costs. Evaluating the reliability of products in a short time is a challenging problem. In this paper, an approach is proposed that combines a group of experts’ judgments and limited failure data. Novel features of this approach are that it can reflect various kinds of information without considering the individual weight and reduces aggregation error in the uncertainty quantification of multiple inconsistent pieces of information. First, an expert system is established by the Bayesian best–worst method and fuzzy logic inference, which collects and aggregates a group of expert opinions to estimate the reliability improvement factor. Then, an adaptive Bayesian melding method is investigated to generate a posterior by inaccurate prior knowledge and limited test data; this method is made more computationally efficient by implementing an improved sampling importance resampling algorithm. Finally, an application for the reliability evaluation of a subsystem of a CNC lathe is discussed to illustrate the framework, which is shown to validate the reasonability and robustness of our proposal.

The effect of modifying the nanostructure of gelatin fiber scaffolds on early angiogenesis in vitro and in vivo

2021 ◽  
Author(s):  
Yanyi Liu ◽  
Xiaoxue Wang ◽  
Fei Hu ◽  
Xiaohui Rausch-fan ◽  
Thorsten Steinberg ◽  
...  
Keyword(s):  
Tissue Regeneration ◽  
Fiber Diameter ◽  
Early Stage ◽  
Fiber Membrane ◽  
Soft Tissue Regeneration ◽  
Two Factors ◽  
Fiber Scaffolds

Abstract Early angiogenesis is one of the key challenges in tissue regeneration. Crosslinking mode and fiber diameter are critical factors to affect the adhesion and proliferation of cells. However, whether and how these two factors affect early angiogenesis remain largely unknown. To address the issue, the optimal crosslinking mode and fiber diameter of gelatin fiber membrane for early angiogenesis in vivo and in vitro were explored in this work. Compared with the post crosslinked gelatin fiber membrane with the same fiber diameter, the 700 nm diameter in situ crosslinked gelatin fiber membrane was found to have smaller roughness (230.67 ± 19 nm) and stronger hydrophilicity (54.77 ± 1.2°), which were suitable for cell growth and adhesion. Moreover, the in situ crosslinked gelatin fiber membrane with a fiber diameter of 1000 nm had significant advantages in early angiogenesis over the two with fiber diameters of 500 and 700 nm by up-regulating the expression of Ang1, VEGF, and integrin-β1. Our findings indicated that the in situ crosslinked gelatin fiber membrane with a diameter of 1000 nm might solve the problem of insufficient blood supply in the early stage of soft tissue regeneration and has broad clinical application prospects in promoting tissue regeneration.

Effect of Water Level and Salinity on the Growth of Annona Glabra L. Seedlings

2021 ◽  
Author(s):  
Edgar Abel Sánchez-García ◽  
Hugo López-Rosas ◽  
Vinicio J. Sosa ◽  
Roberto Lindig-Cisneros ◽  
Patricia Moreno-Casasola
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Coastal Wetland ◽  
Seedling Survival ◽  
Coastal Region ◽  
Average Height ◽  
Wetland Ecosystems ◽  
Natural Establishment ◽  
Two Factors ◽  
Annona Glabra

Abstract During the last century the mean sea level has been increasing at a rate of 0.2 to 0.4 mm·year -1 , and that rate is expected to accelerate during this century. Coastal wetland ecosystems are sensitive to the potential changes and impacts of resulting from a rise in sea level. In the coastal region of the Gulf of Mexico, freshwater swamps are wetlands located further inland than mangroves, and while influenced by the tides maintain freshwater conditions. Due to their location, the rise in sea level could increase the levels of flooding and salinity in these ecosystems. The objective of this study was to evaluate, under greenhouse conditions, the effect of nine flood and salinity treatments on the survival, growth and increase in the biomass of Annona glabra (pond apple) seedlings. The treatments combined two factors: water level (saturation, flood, flood-drought) and salinity (0, 5 and 15 ‰). Germinated seedlings were used (average height: 18.6 ± 1.61 cm). Seedling survival was greater under freshwater conditions. Increase in height and diameter, as well as leaf and biomass gain, were greater under saturation and freshwater conditions. Based on our results, we conclude that under a scenario of rising sea level, increased flood levels and salinity will negatively affect the natural establishment of Annona glabra seedlings in freshwater swamps.

Seed dispersal and site characteristics influence germination and seedling survival of the invasive liana Euonymus fortunei (wintercreeper) in a rural woodland

2018 ◽  
Vol 48 (11) ◽  
pp. 1343-1350 ◽  
Author(s):  
Todd J. Rounsaville ◽  
Carol C. Baskin ◽  
Eric Roemmele ◽  
Mary A. Arthur
Keyword(s):  
Species Diversity ◽  
Seed Germination ◽  
Native Species ◽  
Slow Rate ◽  
Seedling Survival ◽  
Soil Nutrient ◽  
Rate Of Spread ◽  
Site Characteristics ◽  
Euonymus Fortunei

The invasive liana Euonymus fortunei (Turcz.) Hand.-Maz. (wintercreeper) is an emerging invader that through monodominance of woodlands can drastically reduce native species diversity and alter nutrient cycling. We studied how the vegetation and soils of invaded (INV), “native” (NAT), and wintercreeper removal (REM) site treatments influenced seed germination and seedling survival of this invader. The effect of aril (with vs. without) was also tested for wintercreeper seeds under field and in vitro conditions as a proxy for gravity vs. animal dispersal of seed, respectively. Germination was significantly delayed for seeds sown with an aril (vs. without), as well as those sown in INV soils (vs. NAT or REM), but neither site nor aril affected total germination. The proportion of germinated seedlings that survived after the first winter was significantly different based on site (p = 0.054) and aril (p = 0.071) treatments, with lower survival resulting from seeds sown without arils, and for seeds sown in INV sites. Magnesium (Mg) concentrations were significantly higher among INV soils (vs. NAT) and provide further support that wintercreeper is a driver of soil nutrient change. Our findings that aril-enclosed (gravity-dispersed) seeds yielded greater survival, despite being locally dispersed within invaded sites (where survival was lowest), support the historically slow rate of spread for this species.

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