• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 733
  • 402
  • 161
  • 86
  • 59
  • 43
  • 22
  • 20
  • 18
  • 12
  • 12
  • 11
  • 10
  • 7
  • 7
  • Tagged with
  • 1920
  • 312
  • 256
  • 193
  • 153
  • 152
  • 140
  • 130
  • 123
  • 121
  • 118
  • 118
  • 104
  • 93
  • 91
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

Kriptogamų įvairovė skirtingo miškų ūkinės veiklos intensyvumo senuose plačialapių ir mišriuose su plačialapiais medžiais miškuose / Cryptogam diversity in old broadleaved and mixed with broadleaves forests of different forest management intensity

Preikša, Žydrūnas 18 October 2011 (has links)
Darbo tikslas yra ištirti kriptogamų rūšių įvairovės dėsningumus skirtingo miškų ūkinės veiklos intensyvumo senuose plačialapių ir mišriuose su plačialapiais medžiais miškuose. Tikslui pasiekti buvo iškelti šie darbo uždaviniai: 1. Nustatyti indikatorinių kriptogamų rūšių skaičių ir gausą skirtingo miškų ūkinės veiklos intensyvumo brandžiuose medynuose; 2. Nustatyti pagrindinius veiksnius, turinčius įtaką indikatorinių kriptogamų rūšių skaičiui ir gausai. 3. Įvertinti skirtingo miškų ūkinės veiklos intensyvumo įtaką indikatorinių kriptogamų rūšių skaičiui ir gausai. 4. Įvertinti indikatorinių kriptogamų rūšių grupes pagal jų augimo vietą ir aplinkos sąlygas. / The objective was to investigate regularities of diversity of cryptogam species in old broadleaved and mixed forests of different forest management intensity. The research was based on the following hypothesis: cryptogam species richness and abundance in a pristine forest are at least twice bigger than in a commercial forest; even extensive forest cutting has a long-term negative impact on rare cryptogam species; coarse dead wood is an extremely important substratum which maintains high cryptogam diversity in the forest; coarse dead wood is more important than the fine one for rare species survival; decayed dead wood is vital for some rare species survival; multispecied stand increases diversity of substrata and creates favourable conditions for higher number of species. To achieve the objective, the following tasks were set up: 1. To evaluate number and abundance of indicator species of cryptogams in mature stands with different intensity of forest management; 2. To determine main factors, influencing number and abundance of indicator species of cryptogams; 3. To evaluate impact of different intensity of forest management on the number and abundance of indicator species of cryptogams; 4. To evaluate groups of indicator species of cryptogams according to their growing place and environmental conditions.
492

Žemės dirbimo intensyvumo, šiaudų ir žaliosios trąšos įtaka agroekosistemos komponentams miežių pasėlyje / Effect of soil tillage intensity, straw and green manure on agro-ecosystem components in barley

Balandė, Monika 21 June 2013 (has links)
Magistrantūros studijų baigiamajame darbe pateikiami pasėlio sudygimo, tankumo, piktžolėtumo tyrimo duomenys skirtingo intensyvumo žemės dirbimo, padengimo šiaudais ir žaliąja trąša laukeliuose. Stacionarus dviejų veiksnių eksperimentas vykdomas nuo 1999 metų. Tyrimai buvo vykdomi nuo 2011 - 2012 m. Eksperimentas buvo vykdomas pagal tokią schemą: A veiksnys: Šiaudų įterpimas: šiaudai pašalinti (-Š), šiaudai susmulkinti ir paskleisti (+Š). B veiksnys: Žemės dirbimo sistemos. Atlikus tyrimus nustatyta, kad miežių daigų skaičiui trečią dieną nuo dygimo pradžios esminės įtakos turėjo žemės dirbimo intensyvumas. Fone, kur šiaudai buvo susmulkinti ir paskleisti (+Š) esmingai didesnis daigų skaičius, palyginti su giliu arimu (GA), nustatytas laukeliuose, kurie buvo sekliai purenti kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir laukeliuose su žaliąja trąša (ŽTRK). Fone be šiaudų (-Š), palyginus su giliu arimu (GA), esmingai daugiau miežių daigų sudygo sekliai artuose (SA), sekliai purentuose kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir neįdirbtos ražienos (ND) laukeliuose. Dešimtąją dieną nuo dygimo pradžios, tiek fone su susmulkintais ir paskleistais šiaudais, tiek fone be šiaudų esmingai mažiau miežių daigų rasta laukeliuose, kurie buvo sekliai purenti rotoriniu kultivatoriumi (RK). Fone su šiaudais taip pat esminiai skirtumai nustatyti laukeliuose kur sėta į neįdirbtą ražieną (ND). Produktyvių stiebų skaičiui neturėjo... [toliau žr. visą tekstą] / Master's thesis presents data of a study of crop germination, density, weed and earthworm population in fields varying in intensity of tillage, straw and green fertilizer coverage. Stationary two-factor experiment is being carried out since 1999. Studies were carried out from 2011 – 2012 . The experiment was carried out according to the following scheme: factor A: Straw incorporation: straw removal (-Š), straw shredded and spread out (+ Š). Factor B: tillage systems. The research found that the number of barley sprouts on the third day from the beginning of germination is essentially influenced by tillage intensity. In area, where the straw were chopped and spread (+Š) substantially increased the number of sprouts in comparison with deep plowing (GA), has been determined in the fields that have been consistently levelled using harrow tines and flatcutting disc implements (KL). Area without straw (-Š) in comparison with deep ploughing (GA), substantially more barley seeds germinated in shallow ploughed (SA), shallow tine cultivator tines and flatcutting disc implements (KL) and the uncultivated stubble (ND) fields. Tenth day after the beginning of germination area with chopped or spread straw and area without straw in the background substantially less barley plants found in fields that have been consistently leveled harrow (RK). In the area with straw as well as in the area where sown in no-till stubble (ND) substantial differences were dicovered. Number of productive stems... [to full text]
493

Effects of block periodization training versus traditional periodization training in trained cross country skiers

Bakken, Timo Andre January 2013 (has links)
Aim The overall aim of this study was to develop a broader understanding on how to optimize the organization of aerobic endurance training programs, and especially how to better organize high-intensity training (HIT) and low intensity training (LIT) to give an optimum endurance performance progress. Method This study compared the effects of two different training organization methods in trained cross-country (XC) skiers and biathletes. During a 5 week intervention period, one group of athletes (n = 10, 7 men and 3 women, age 23 ± 9 years) performed block periodization (BP) training with 5-1-3-1-1 HIT sessions in the respective weeks. The other group of athletes(n = 9, 7 men and 2 women, age 22 ± 5) followed a more traditional periodization (TRAD) method performing 2-2-3-2-2 HIT sessions. LIT was interspersed between the HIT sessions so that both groups performed similar total volumes of HIT and LIT during the intervention period. Results The BP group increased relative and absolute VO2max (2.6 ± 3.6% and 2.0 ± 2.5%, P < 0.05) and time to exhaustion (6.1 ± 6.4%, P < 0.01). No changes were seen in the TRAD group on relative or absolute VO2max (0.8 ± 3.5% and -0.1 ± 3.0%) or time to exhaustion (-2.0 ± 7.7%). Mean effects size (ES) of the relative and absolute improvement in VO2max and time to exhaustion revealed small to moderate effects of performing BP training vs. TRAD training (ES range from 0.51 to 1.14). Conclusions This study indicates that organizing endurance training in XC skiers with block periodization training give better adaptations compared to performing traditional periodization training during a 5 week training period when performing similar volumes of high-intensity and low intensity training.
494

Highly Efficient Thermal Ablation of Silicon and Ablation in Other Materials

Yu, Joe X.Z. 06 June 2011 (has links)
Laser micromachining has become increasing prominent in various industries given its speed, lack of tool wear, and ability to create features on the order of micrometres. Inherent stochastic variations from thermal ablation along with detrimental heat effects, however, limit the feasibility of achieving high precision. The high number of control parameters that make laser micromachining versatile also hinders optimization due to high exploration time. The introduction of high intensity nonlinear ablation leads to more precise cuts but at a much higher, often restrictive, cost. The work here shows that by combining an imaging technique frequently used in ophthalmology called optical coherence tomography (OCT) with a machining platform, in situ observation of ablation can be made. This combination, known as in-line coherent imaging (ICI), allows information to be gathered about the dynamics of the ablation process. Experimental results show that quality cutting of silicon can be achieved with thermal ablation and at a wavelength of 1070 nm. This result is surprising as silicon absorbs this wavelength very weakly at room temperature. It is shown here that a nonlinear thermal dependence in absorption allows a cascaded absorption effect to enable machining. With the aid of ICI, the model shown here is able to accurately predict the thermal ablation rate and help understand the ablation process. The high quality cutting achieved allows for a more cost efficient alternative to current techniques using ultraviolet diode-pumped solid state (UV DPSS) systems. Where thermal effects such as heat-affected zones (HAZ) cannot be overcome, high intensity nonlinear ablation allows the processing of lead zirconate titanate (PZT) for high frequency arrays (used in ultrasound applications) at speeds two orders of magnitude greater than found in the literature, and potential feature sizes (< 100 µm) in polymethyl methacrylate (PMMA) unachievable by thermal ablation. The ablation mechanism here is Coulombic explosion (CE), which is a non-thermal process. Coupled with demonstrated manual and automatic feedback abilities of ICI, the processes shown here may open up new avenues for fabrication. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2011-05-31 15:02:55.547
495

Opportunities For Enhancing Vigorous Physical Activity Within The New Brunswick Physical Education Curriculum

Parsons, Kari Ann January 2010 (has links)
PURPOSE: To determine if participation in a short-term, high intensity physical education (PE) intervention that respected the multiple goals of the PE curriculum would result in any health- and/or fitness-related improvements for grade four and five students. METHODS: Seventy-six students were divided into a control and intervention group (CG & IG). During 15 successive classes, the IG participated in six minutes of high intensity activities while no changes were made to the structure of the CG’s PE class. Accelerometers and direct observation were used to quantify the percentage of moderate-to-vigorous physical activity (%MVPA). Health- and performance-related measures were assessed pre- and post-intervention. RESULTS: Students spent an average of 27% of their PE class engaged in MVPA. Within this category, the intervention was successful at increasing students’ VPA levels by 7.7%. Observations regarding pedagogical practices are also reported. CONCLUSIONS: Participating in a PE intervention can increase students’ PA levels without compromising the goals of the PE curriculum.
496

Expansion and Osteogenic Differentiation of Human Umbilical Cord Perivascular Stem Cells by Low Intensity Pulsed Ultrasound for Dentofacial Tissue Engineering

Aldosary, Tagreed Unknown Date
No description available.
497

Effect of growth hormone and therapeutic ultrasound on mandible and mandibular condyle

Khan, Imran Unknown Date
No description available.
498

Modeling cavitation in a high intensity agitation cell

Jose, July Unknown Date
No description available.
499

Recognition and Importance of Ethical Factors in Accountants' Decision Making

Fiolleau, Krista J. Unknown Date
No description available.
500

Prediction of Rainfall Runoff for Soil Cover Modelling

Jubinville, Sarah K. Unknown Date
No description available.

Page generated in 0.0436 seconds