1,721,044 research outputs found
Modeling Productivity and Costs of Mechanized Tree Length Skidding Operations
No full textSkidding operation constitute the entire process of moving felled trees from the stump site to the roadside landing. This operation normally bears substantial amount of the mill delivery costs. Thus, detailed information on productivity and cost is important for planning of cost-effective skidding operation. This study was conducted at Sao hill Forest plantation to quantify productivity and costs of tree length skidding operations. Continuous time study technique using snap-back method was used for time recording. Costs data were obtained from Mufindi Paper Mill logging department. Productivity and costs modeling, were performed using Microsoft excel. The analysis, showed that; the average productivity of the grapple skidder using tree length (TL) ranges between 398.423 m3/hr at a distance of 10 m and 49.862 m3/hr at a distance of 80 m. On the costs analysis, the unit skidding costs tends to increase with an increase of skidding distance (m) from 512.197 TZS/m3 at a distance of 10 m to 4,092.675 TZS/m3 at a distance of 80 m. Based on these findings it is recommended that variables distance and volume are the core factors to consider during planning to enhance efficient and costs effective skidding operation
Impact of logging practices on second-generation stand growth of Pinus patula at Sao hill forest plantation in Tanzania
No full textJournal ArticleLogging is a fundamental component of
forest management, facilitating the
establishment of new stands through the
removal of mature trees. However, logging
operations often induce substantial soil
disturbances, which may adversely affect
the growth of second-generation stands.
This study aimed to assess the impact of
logging on the growth of second-generation
Pinus patula stands at Sao Hill Plantation,
Tanzania (SHFP), specifically focusing on
the impacts of logging on stand growth and
forest soil. Six compartments, three from
each generation, representing stand ages of
1, 3, and 6 years, totaling 180 systematically
sampled plots, each measuring 20 x 20
meters. First- and second-generation stands
were treated as experimental groups. An
independent t-test was used to analyze the
impact of logging on stand growth across
generations. Stand growth parameters
including the number of stems, tree height,
and diameter at breast height (DBH)
decreased by 6.5% to 12.3% in secondgeneration
stands compared to firstgeneration
stands. Soil bulk density in
second-generation stand increased by 25.7%
and 26.2% in the top 10 cm and 20 cm of
soil, respectively, compared to the firstgeneration
stand. The findings emphasize
the critical role of adopting reduced-impact
logging techniques to minimize soil
compaction, thereby supporting the longterm
productivity
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Impact of logging practices on second-generation stand growth of Pinus patula at Sao hill forest plantation in Tanzania
No full textJournal ArticleLogging is a fundamental component of
forest management, facilitating the
establishment of new stands through the
removal of mature trees. However, logging
operations often induce substantial soil
disturbances, which may adversely affect
the growth of second-generation stands.
This study aimed to assess the impact of
logging on the growth of second-generation
Pinus patula stands at Sao Hill Plantation,
Tanzania (SHFP), specifically focusing on
the impacts of logging on stand growth and
forest soil. Six compartments, three from
each generation, representing stand ages of
1, 3, and 6 years, totaling 180 systematically
sampled plots, each measuring 20 x 20
meters. First- and second-generation stands
were treated as experimental groups. An
independent t-test was used to analyze the
impact of logging on stand growth across
generations. Stand growth parameters
including the number of stems, tree height,
and diameter at breast height (DBH)
decreased by 6.5% to 12.3% in secondgeneration
stands compared to firstgeneration
stands. Soil bulk density in
second-generation stand increased by 25.7%
and 26.2% in the top 10 cm and 20 cm of
soil, respectively, compared to the firstgeneration
stand. The findings emphasize
the critical role of adopting reduced-impact
logging techniques to minimize soil
compaction, thereby supporting the longterm
productivity
Modeling productivity and costs of mechanized tree length skidding operations
No full textJournal ArticleSkidding operation constitute the entire
process of moving felled trees from the
stump site to the roadside landing. This
operation normally bears substantial amount
of the mill delivery costs. Thus, detailed
information on productivity and cost is
important for planning of cost-effective
skidding operation. This study was
conducted at Sao hill Forest plantation to
quantify productivity and costs of tree length
skidding operations. Continuous time study
technique using snap-back method was used
for time recording. Costs data were obtained
from Mufindi Paper Mill logging
department.
Productivity
and
costs
modeling, were performed using Microsoft
excel. The analysis, showed that; the average
productivity of the grapple skidder using tree
length (TL) ranges between 398.423 m 3 /hr at
a distance of 10 m and 49.862 m 3 /hr at a
distance of 80 m. On the costs analysis, the
unit skidding costs tends to increase with an
increase of skidding distance (m) from
512.197 TZS/m 3 at a distance of 10 m to
4,092.675 TZS/m 3 at a distance of 80 m.
Based on these findings it is recommended
that variables distance and volume are the
core factors to consider during planning to
enhance efficient and costs effective
skidding operation
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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