scholarly journals When the shifting agriculture is gone: functionality of Atlantic Coastal Forest in abandoned farming sites

2008 ◽  
Vol 3 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Rogério Ribeiro de Oliveira
Keyword(s):  
Litter Production ◽  
Forest Site ◽  
Secondary Forests ◽  
Litter Accumulation ◽  
Atlantic Coastal Forest ◽  
Long Time ◽  
Landscape Functionality ◽  
Almost All ◽  
Forest Lands ◽  
Climax Forest

Slash-and-burn agriculture has been practiced for a very long time by the traditional populations (caiçaras) on Ilha Grande, Rio de Janeiro State, Brazil. After a few years of use the plots are abandoned to fallow. We examined the processes of litter production and decomposition and the relationships between forest lands used by caiçara populations and landscape functionality. Five and 25-year-old forests growing on areas once used for subsistence agriculture were compared to a near-climax forest site. No significant differences between the three areas were noted in terms of litter production over a 2-yr period; the average litter productions were 9,927, 8,707 and 10,031 kg/ha/yr for the 5-year, 25-year and climax forests respectively. N and K nutrient input through litter was greatest in the climax forest; P and Mg input was greatest in the 5-yr forest; and Na greatest in the 25-yr forest. Ground litter accumulation (3,040-3,730 kg/ha/yr) was not significantly different in the three areas. Litter turnover times (1/K) were 0.33, 0.42 and 0.38 for the 5-yr, 25-yr and climax forests respectively. These secondary forests cover almost all of Ilha Grande and demonstrate low species diversity, but they have production and decomposition systems similar to those of mature forests.

Tropical secondary forests

1990 ◽  
Vol 6 (1) ◽  
pp. 1-32 ◽  
Author(s):  
Sandra Brown ◽  
Ariel E. Lugo
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Net Primary Productivity ◽  
Secondary Forest ◽  
Ground Vegetation ◽  
Litter Production ◽  
Secondary Forests ◽  
Forest Lands ◽  
The Tropics ◽  
The Impact

ABSTRACTThe literature on tropical secondary forests, defined as those resulting from human disturbance (e.g. logged forests and forest fallows), is reviewed to address questions related to their extent, rates of formation, ecological characteristics, values and uses to humans, and potential for management. Secondary forests are extensive in the tropics, accounting for about 40% of the total forest area and their rates of formation are about 9 million ha yr−1. Geographical differences in the extent, rates of formation and types of forest being converted exist.Secondary forests appear to accumulate woody plant species at a relatively rapid rate but the mechanisms involved are complex and no clear pattern emerged. Compared to mature forests, the structure of secondary forest vegetation is simple, although age, climate and soil type are modifying factors. Biomass accumulates rapidly in secondary forests, up to 100 t ha−1 during the first 15 yr or so, but history of disturbance may modify this trend. Like biomass, high rates of litter production are established relatively quickly, up to 12–13 t ha−1 yr−1 by age 12–15 yr. And, in younger secondary forests (< 20 yr), litter production is a higher fraction of the net primary productivity than stemwood biomass production. More organic matter is pro duced and transferred to the soil in younger secondary forests than is stored in above-ground vegetation. The impact of this on soil organic matter is significant and explains why the recovery of organic matter in the soil under secondary forests is relatively fast (50 yr or so). Nutrients are accumulated rapidly in secondary vegetation, and are returned quickly by litterfall and decomposition for uptake by roots.We propose a model of the gains and losses, yields and costs, and benefits and tradeoffs to people from the current land-use changes occurring in the tropics. When the conversion of forest lands to secondary forests and agriculture is too fast or land-use stages are skipped, society loses goods and services. To avoid such a loss, we advocate management of tropical forest lands within a landscape perspective, a possibility in the tropics because land tenures and development projects are often large.

A Thorough Theoretical Exploration of Intriguing Characteristics of Cyclo[18]carbon: Geometry, Bonding Nature, Aromaticity, Weak Interaction, Reactivity, Excited States, Vibrations, Molecular Dynamics and Various Molecular Properties

2019 ◽  
Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu
Keyword(s):  
Molecular Dynamics ◽  
Excited States ◽  
Electronic Excitation ◽  
Ring Structure ◽  
Molecular Properties ◽  
Molecular Vibration ◽  
Full Characterization ◽  
Long Time ◽  
Almost All

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.

A Thorough Theoretical Exploration of Intriguing Characteristics of Cyclo[18]carbon: Geometry, Bonding Nature, Aromaticity, Weak Interaction, Reactivity, Excited States, Vibrations, Molecular Dynamics and Various Molecular Properties

2019 ◽  
Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu
Keyword(s):  
Molecular Dynamics ◽  
Excited States ◽  
Electronic Excitation ◽  
Ring Structure ◽  
Molecular Properties ◽  
Molecular Vibration ◽  
Full Characterization ◽  
Long Time ◽  
Almost All

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.

Missing Value Imputation Using ANN Optimized by Genetic Algorithm

2018 ◽  
Vol 5 (2) ◽  
pp. 41-57 ◽  
Author(s):  
Anjana Mishra ◽  
Bighnaraj Naik ◽  
Suresh Kumar Srichandan
Keyword(s):  
Genetic Algorithm ◽  
Missing Data ◽  
Data Entry ◽  
Missing Information ◽  
Missing Value ◽  
Need Analysis ◽  
Processing Data ◽  
Real World Applications ◽  
Long Time ◽  
Almost All

Missing value arises in almost all serious statistical analyses and creates numerous problems in processing data in databases. In real world applications, information may be missing due to instrumental errors, optional fields and non-response to some questions in surveys, data entry errors, etc. Most of the data mining techniques need analysis of complete data without any missing information and this induces researchers to develop efficient methods to handle them. It is one of the most important areas where research is being carried out for a long time in various domains. The objective of this article is to handle missing data, using an evolutionary (genetic) algorithm including some relatively simple methodologies that can often yield reasonable results. The proposed method uses genetic algorithm and multi-layer perceptron (MLP) for accurately predicting missing data with higher accuracy.

scholarly journals Seasonal changes of biological condition and reproductive cycle of hampback shrimp Pandalus hypsinotus (Caridea, Pandalidae) in the Tatar Strait

2021 ◽  
Vol 201 (3) ◽  
pp. 547-560
Author(s):  
D. N. Yuriev ◽  
G. V. Zhukovskaya
Keyword(s):  
Reproductive Cycle ◽  
Japan Sea ◽  
Biological Condition ◽  
Tatar Strait ◽  
Stage Of Development ◽  
Long Time ◽  
Pass Through ◽  
The Individual ◽  
Almost All ◽  
Trawl Catches

Research and commercial trawl catches of humpback shrimp Pandalus hypsinotus from the Tatar Strait (Japan Sea) in 2004–2020 were investigated, with bioanalysis of about 45 thousand specimens. Average timing of group molting, spawning, and eggs laying are determined, terms of gonads and eggs development are estimated. Prespawning and molting of the females occur between January-April, with the peaks in early February and middle February, respectively. All oviparous females have 30–40 days to lay eggs, and molt during 50–55 days; the peak of the eggs laying occurs in late June. The males molt in July-August, afterwards the largest individuals change gender and new intersexes are formed. The males have the second molting in October-December, with the peak in late November. In January, after finish of the males molting, a new annual reproduction cycle starts from the prespawning molting of females. Both vitellogenesis and embryogenesis are observed through the year, though females with developing gonads prevail from August to January (because of a long time span between winter and summer moltings while the egg carrying continued 15 months) but oviparous females — from February to July. The individual reproductive cycle of Pandalus hypsinotus in the Tatar Strait lasts 24 months, with 9 months of vitellogenesis (quick growth of gonads) and 15 months of embryogenesis. During the 2-year reproductive cycle, most of females pass through the following stages: i) gonads development (just after eggs laying) when almost all oviparous females (up to 95 % in May) have green gonads under carapace that corresponds to the stage of development «eggs laid — gonads weakly developed»; ii) summer molting from August when females lose hairs on pleopods and the gonads growth accelerates; iii) respawning in January-March (together with the firstly spawning intersexes, with slight delay of the latter); iv) initial developing of eggs during summer; v) stage of «eyed eggs» from December to March; and vi) eggs laying and molting from late March to late May; then the 2-year reproductive cycle repeats.

scholarly journals PENGGUNAAN WEBSITE SEBAGAI MEDIA PROMOSI HOME INDUSTRY PADA TIM PENGGERAK PKK

2019 ◽  
Vol 2 (2) ◽  
pp. 113-118
Author(s):  
Realize Realize ◽  
Tukino Tukino
Keyword(s):  
Community Service ◽  
The Internet ◽  
Internet Media ◽  
Household Products ◽  
Main Target ◽  
Long Time ◽  
The Media ◽  
The Government ◽  
Use Of The Internet ◽  
Almost All

Home industry production results are only traditionally managed as promoted by word of mouth, and sometimes rely solely on the number of visitors to the sales place of the product, so the product takes a long time to increase sales volume. Now with capitalize a set of computers or smartphones that have been equipped with the Internet network can be used as a tool or media to publish all activities / promotional activities undertaken by the domestic business actors. In this activity, business activists will be given material about what the website, especially weblog and its benefits, how to make it, and how to use and manage it properly to support and improve the ability in promoting the product. This is not without reason, because almost all citizens who already have a household business is less understand the use of the internet let alone use the Internet media as one of the media to promote household products that they produce. The main target in the implementation of community service activities is to improve the ability of the community in the utilization of the Internet as a powerful medium as a partner of the government in moving the economic factors.

Abstract 533: Lymph is a Vehicle for Extracellular Vesicles in Mice

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Andreea Milasan ◽  
Nicolas Tessandier ◽  
Sisareuth Tan ◽  
Alain Brisson ◽  
Eric Boilard ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Biological Fluids ◽  
Lymphatic Vessels ◽  
The Body ◽  
Artery Wall ◽  
Waste Products ◽  
Peripheral Tissues ◽  
Cellular Debris ◽  
Long Time ◽  
Almost All

Introduction: Although for a long time considered as simple cellular debris, extracellular vesicles (EVs) are now known to be involved in many pathophysiological processes such as thrombosis, autoimmune diseases and inflammation. Due to their diversity and presence in different tissues, EVs are considered important biomarkers and thus, their precise detection in various biological fluids is important to better understand all their different functional activities. The lymphatic system works in close collaboration with the cardiovascular system to preserve fluid balance throughout the body. Lymphatic vessels are present in almost all vascularized tissues, including the brain and the artery wall, and their role in these organ-related pathologies are under intense investigations. Hypothesis: Since lymphatic vessels are often perceived as "sewers", due to their role in removing interstitial fluid and waste products from peripheral tissues such as the artery wall, we herein want to qualitatively and quantitatively assess the presence of EVs in circulating lymph. Methods and Results: Using several approaches such as a Zetasizer Nano S, electron microscopy and flow cytometry analysis, we have detected and characterized EVs in lymph of healthy animals, and found that these EVs are inclusively derived from red blood cells, platelets and lymphatic endothelial cells. Analysis of lymph from atherosclerotic mice (Ldlr -/- ) confirmed the idea that EVs number and origin varies according to the pathological setting. Conclusion: Herein, we show for the first time that EVs are present in lymph and that their level and origin vary in atherosclerosis. Our work will be setting the stage to a better understanding of the mechanism underlying EV accumulation in peripheral tissues during inflammation, and to better control related diseases.

scholarly journals Preparedness is Essential for Western Pacific Islands During the COVID-19 Pandemic

2020 ◽  
pp. 1-5
Author(s):  
Yujie Mei ◽  
Jijia Hu
Keyword(s):  
Pacific Islands ◽  
Case Fatality ◽  
Western Pacific ◽  
Western Pacific Region ◽  
Dense Population ◽  
First Report ◽  
First Case ◽  
Long Time ◽  
Almost All ◽  
The Western Pacific

ABSTRACT Objectives: To clarify the pandemic status in Western Pacific countries or territories. Methods: The WHO’s daily situation reports of COVID-19 were reviewed from January 20, 2020, to March 24, 2020. Changes in the infections, deaths, and the case fatality rate (CFR) in Western Pacific countries or territories were counted. Results: As of March 24, a total of 17 countries or territories had reported the presence of COVID-19 in the Western Pacific Region, 96,580 people have been infected and a total of 3502 deaths. Fifty-three percent (9/17) of these countries or territories had their first case within 2 wk since the WHO’s first report, most are China’s neighbors with a large and dense population. No other country or territory in this region reported a new infection from January 30 to February 28. However, 8 (47.0%) countries or territories have reported the first cases in 3 wk since February 28, almost all are islands. Many countries maintained a small number of infections for a long time after the first report, but a rapid increase occurred later. Deaths occurred in 8 countries with a total CFR of 3.63%, and the CFR varies widely, from 0.39% (Singapore) to 7.14% (Philippines). Conclusions: The regional spread of COVID-19 urgently requires an aggressive preparedness for the Western Pacific Islands.

scholarly journals Supernovae as a Cosmological Tool

1983 ◽  
Vol 104 ◽  
pp. 227-229
Author(s):  
Virginia Trimble
Keyword(s):  
Dynamical Evolution ◽  
The Other ◽  
Long Time ◽  
Evolution Of Structure ◽  
Almost All ◽  
The Universe ◽  
The Way

Cosmology can mean many different things to different people. Sandage (1970) once described it as “the search for two numbers” (Ho and qo). At the other end of the spectrum, it may comprise almost all the interesting bits of astronomy and physics that bear on how the universe got to be the way it is. Supernovae can probe many of these bits because they are bright, have been going on for a long time, and contribute directly to the chemical and, perhaps, dynamical evolution of structure in the universe.

Sign in / Sign up

Export Citation Format

Share Document