1,720,974 research outputs found
Järvamaa tehisjärvede seisund ja rekreatiivse kasutamise võimalused
No full texthttps://www.ester.ee/record=b5462815*es
The impact of Sillaoru hydroelectric power station on the downstream migration of salmon smolts in the Purtse River
Get PDFBakalaureusetöö
Vee ja maismaa ökosüsteemide rakendusbioloogia õppekavalEesti jõgedel on üle 50 hüdroelektrijaamaga (HEJ) paisu ning kõigi nende juures on oluliseks probleemiks kaladele ohutute allarände tingimuste tagamine. 2015. a Purtse jõel Sillaoru HEJ juures läbi viidud lõhesmoltide laskuva rände uuring oli Eestis esimene sellelaadne. Eesmärgiks oli uurida smoltide laskuva rände ajalist ja ruumilist kulgu ning erinevate rändeteede ohutust töötava HEJ, kalapääsu ja liigveelaskmega paisu juures. Uuringus kasutati RMK Põlula kalakasvatuskeskuses ettekasvatatud lõhesmolte, kes enne asustamist märgistati rasvauime lõikamisega, 40 isendit ka individuaalsete akustiliste märgistega. Kalade laskuva rände kulgu jälgiti mõrrapüükide ja akustilise telemeetria meetodit kasutades. Selgus, et vaatamata suhteliselt väikesele vooluhulgale valis enamik smolte (71–74%) paisu juures laskumiseks kalapääsu. Oluline osa laskujatest (23–26%) valis rändeteeks põhivoolul oleva HEJ derivatsioonikanali ning vaid üksikud isendid (3%) eelistasid allarändeteena paisu liigveelasku, mille vooluhulk oli lähedane kalapääsu vooluhulgale. Rände ajaline analüüs näitas, et asustatud kalad alustasid koheselt allarännet. Esimesel päeval läbis paisu 69%, teisel 20%, kolmandal 6% ja neljandal 3% laskujatest. Laskumise intensiivsus oli kõrgem perioodil õhtul kella 18-st hommikul kella 6-ni, maksimum vahetult enne südaööd. Laskumisel läbi HEJ oli smoltide kohene suremus vähemalt 33% ning järelsuremus 7%. Laskumisel üle liigveelaskme ja läbi kalapääsu suremus puudus. Uuringust järeldub, et senini seadusega nõutud 25 mm võre HEJ turbiinide sissevoolul pole piisava tihedusega tõkestamaks lõhesmoltide sattumist turbiinidesse.There are more than 50 dams with hydroelectric power stations (HPS) on Estonian rivers and providing safe conditions for the downstream migration of fish is an important issue with all of them. The study of the downstream migration of salmon smolts, conducted in 2015 at the Sillaoru HPS on Purtse river, was the first of its kind in Estonia. The goal was to analyze the spatial and temporal progress of the downstream migration of smolts and the safety of passage in the HPS channel, fish pass and water spillway. The salmon smolts used in the study originated from RMK Põlula fish rearing centre. All of them were marked by removing the adipose fin and 40 of the smolts were fitted with individual acoustic trackers. The downstream migration was monitored using trapping and acoustic telemetry. Most smolts (71–74%) preferred the fish pass for downstream migration despite the relatively low water flow. A significant part of the smolts (23–26%) chose the HPS channel and only a few (3%) migrated over the water spillway. The fish started their downstream migration right after being introduced to the river. 69% of the smolts descended through the dam complex on the first day, followed by 20% on the second, 6% on the third and 3% on the fourth day. The descent intensity was highest from 18 PM to 6 AM, reaching the maximum just before midnight. The immediate mortality while descending through the HPS was at least 33%, with an after-mortality of 7%. The mortality while descending through the fish pass or water spillway was 0. The study shows that a grate with 25 mm (legally required minimum) gaps is not sufficient to stop smolts from reaching the HPS channel
Overview of Estonian fish passes
Get PDFTöö eesmärgiks oli teada saada kui palju on viimasel ajal Eestisse rajatud kalapääsusid ning
kui palju on veel plaanis rajada. Töö jaoks vajalikud andmed sain Meelis Tambetsilt, Eesti
Loodushoiu Keskusest ning Tauno Jürgensteinilt, SA Eesti Forellist. Töö tulemus täitis seatud
eesmärgid ning sain teada et alates 2009. aastast alates on 2014. aasta alguseks rajatud meie
vooluveekogudele 40 kalapääsu ning 2015. aastaks plaanitakse rajada veel 29 pääsu.
Lühikokkuvõte inglise keeles (max 1 A4 lk.):
The aim of this research was to find out how many fish passes have recently beel built in
Estonia and also how many fish passes are still planned to built. The data, which was required
for the research has received from Meelis Tambets, Eesti Loodushoiu Keskus and also from
Tauno Jürgestein, SA Eesti Forell. The results of the research fulfilled the goals. I found out,
that since 2009 to the beginning of 2014, there are built 40 fish passes to our watercourses in
Estonia and about 29 fish passes are planned to built to 2015.The main purpose of the current bachelor’s paper was to find out about and to give an overview
of the fish passes built and still under construction in Estonia.
In Estonian flowing water bodies there are about 1000 dams blocking up the fishes migrating
ways. According to the water law the owners of the dams are obliged to build fish passes on the
living and spawning areas of salmon, brown trout, salmon trout and grayling.
By the year 2013, 40 fish passes have been built all over Estonia, 22 of them are natural, as close
to the nature as possible. By the year 2015, 29 more fish passes will be completed, 24 of them
will be natural.
It is very important to fulfill all the criteria so that the fish pass works effectively and orderly. An
orderly and operating fish pass is easily detectable, easily passable, less stress creating and
harmless for the fish.
The most preferable way for building fish passes has been and still is to make them as close to the
nature as possible. A fish pass is the more natural, the less concrete is used and which are not
operated by hi- tech machinery, but by the nature itself.
I was an eyewitness of the fact that a fish pass really works. In 2012 one of the first rapids- type
fish pass in Estonia was opened on the Vastse- Roosa dam. On the first day a lamprey come from
below the dam, crossed the fish pass with no trouble and went on upstream. Then we can say that
the fish passes built in the natural way operate effectively, and people’s work has good results. So
both sides are happy: the people who can see that the fish have no problem overcoming the
obstacles, and the fish themselves that can follow their senses and act under the call of the wild
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
