Regeneration Αnalysis of the Juniperus excelsa Mixed Stands in Prespa National Park of Greece as a Base for the Assessment of the Appropriate Silvicultural Treatment for the Conservation of the Species

Analysis of the regeneration of mixed stands of Juniperus excelsa (Greek juniper) in Prespa National Park revealed two distinct structural types: a) stands with small gaps, and b) stands without gaps. Fifteen 500-square-meter sample plots were established in each structural type. All plant species were counted in each plot, and Greek juniper plants were classified into two groups based on their regeneration status. Plants that have been established and grow under the facilitation of other plants fall into the first group, while those that have been established and grow in light, in canopy gaps, belong to the second. Regarding the regeneration of Greek juniper in the Greek juniper mixed stands with small gaps, facilitation is not the primary mechanism at work. There are less Greek juniper regeneration plants in the gap-free structural type, compared with the small-gap type. Greek juniper regeneration plant density will decrease if gaps close. Finally, in both structural types, the other species\u27 regeneration plants exhibit higher density than those of Greek juniper. Creating gaps around Greek juniper trees by extensive intervention is one of the most successful ways for the forest practice to protect the Greek juniper mixed stands

NUMERICAL SIMULATION OF SINGLE POINT INCREMENTAL FORMING FOR ASYMMETRIC PARTS

Single point incremental forming (SPIF) that will produce non-symmetric sheet metal parts has been rarely dealt with so far. SPIF of a Francis hydro-turbine vane made of aluminum alloy is studied as a typical example in this work. At first, a concave geometry, encompassing the desired vane shape is designed, from which the formed part will be ultimately cut out. The necessary SPIF toolpaths are created by using the CAM software normally used for milling processes. Based on these toolpaths, a finite element simulation is setup using shell elements with a particular emphasis on substantial time scaling and due care on tool-sheet contact parameters. For validation purposes the part was manufactured and digitized by a white light scanner. It exhibited tolerable deviation from the targeted nominal geometry. Simulation predicted a significant part of this deviation, proving its indispensability in checking out toolpaths and process parameters for non-symmetric parts, yet at non-negligible computational time

Dormancy-Breaking Requirements and Germination for Seeds of Ostrya carpinifolia Scop.

The present research aims at investigating the combined effects of warm stratification (WS)+cold stratification (CS), and gibberellic acid (GA3)+cold stratification (CS) on breaking dormancy and germination in seeds of Ostrya carpinifolia. The seeds were subjected to WS (20-25 °C) for 0, 1 and 2 months and were subsequently cold stratified at 3-5 °C for 0, 1, 2, 3 and 4 months (1st experiment). A further amount of seeds was treated with 500, 1000 or 2000 ppm GA3 for 30 hours and then cold stratified at 3-5 °C for 0, 1, 2, 3 and 4 months (2nd experiment). No germination was observed in the seeds subjected to only WS (1 and 2 months) or CS for 1 month indicating that the seeds of O. carpinifolia are dormant. A 4-month stratification (1 month WS+3 month CS or 4 months CS) fully released dormancy and led to a high germination percentage (94.17 and 98.34% respectively) in a short time (7.12 and 7.00 days respectively). Warm stratification treatment prior to CS, was not required in order to break the seed dormancy of O. carpinifolia and also did not reduce the length of the (total) stratification period required for breaking seed dormancy. Gibberellic acid (GA3) application entirely replaced the CS period required for breaking seed dormancy. The germination of the seeds treated only with 2000 ppm GA3 (0 months of CS) was (94.17%) as high as the germination of the seeds subjected to 4 months of CS (98.34%). It is obvious that the seedcoat of O. carpinifolia seeds was permeable to GA3 and did not mechanically restrict embryo growth, thus, the seeds did not exhibit physical dormancy. Based on dormancy breaking requirements, the O. carpinifolia seeds displayed intermediate physiological dormancy

The Influence of Position and Site on the Height Growth of Young Populus tremula L. Ramets in Low Elevation Formations in Northeastern Greece

This study was carried out in the central part of Nestos Valley in northeastern Greece. The main objective was to examine the effect of different position (dominant, suppressed, side-shaded) and site productivities on the height growth of young Populus tremula L. clonal ramets in low elevation formations of the species. Fifty-four ramets growing in different positions and sites were cut and studied. Stem analysis was conducted and the height of each ramet at the age of 10 years was calculated. The main results of this research indicate that the dominant ramets on good productivity sites have greater height at the age of 10 years, when compared with the corresponding ramets on medium productivity sites. On the contrary, in suppressed and side-shaded ramets, there is no statistically significant difference in height at the age of 10 years between the two site types. This pattern indicates that competition is the procedure that characterizes the relationships between ramets in the investigated formations. The heights of dominant P. tremula ramets presented in this study are very satisfactory for the species, compared with the height of P. tremula trees from other regions of the species expansion reported in other studies

Site quality assessment for Pinus sylvestris L. in mixed forests of the central part of "Rhodope Mountains" in northeastern Greece

In this work, site index curves are developed for Pinus sylvestris in Greece, because of the ecological, social and economic importance of the species. Data from the forest of the Central Rhodope Mountains of north-eastern Greece are used. Thirty one dominant trees, which had the mean height of the 100 tallest trees per hectare were randomly selected and cut, in the 1990s. For each sampled tree a stem analysis was conducted. The selected height-age model for Pinus sylvestris was . The mean annual increment from stem analyses was equal to 0.212 m, corresponding to a base age of 68 years. The height estimation, calculated by the selected model, for a 68 year-old tree, is 23 m (SI23). Using the quadratic model as the guide curve for the development of anamorphic site index curves, we produced two more curves, SI20 and SI27. The main findings of this research are that Pinus sylvestris seems to grow faster in height in the productive site of the present study compared with that of Sweden, its growth is similar to that of the two most productive sites in forests in northwestern Spain, and it seems comparable to the fairly productive sites of northwestern Turkey

Individual Resonant Frequencies at Low-Gamma Range and Cognitive Processing Speed

Brain electrophysiological activity within the low gamma frequencies (30–80 Hz) has been proposed to reflect information encoding and transfer processes. The 40-Hz auditory steadystate response (40-Hz ASSR) is frequently discussed in relation to changed cognitive processing in neuropsychiatric disorders. However, the relationship between ASSRs and cognitive functioning still remains unclear. Most of the studies assessed the single frequency ASSR, while the individual resonance frequency in the gamma range (30–60 Hz), also called individual gamma frequency (IGF), has received limited attention thus far. Nevertheless, IGF potentially might better reflect individual network characteristics than standardly utilized 40-Hz ASSRs. Here, we focused on the processing speed across different types of cognitive tasks and explored its relationship with responses at 40 Hz and at IGFs in an attempt to uncover how IGFs relate to certain aspects of cognitive functioning. We show that gamma activity is related to the performance speed on complex cognitive task tapping planning and problem solving, both when responses at 40 Hz and at IGFs were evaluated. With the individualized approach, the observed associations were found to be somewhat stronger, and the association seemed to primarily reflect individual differences in higherorder cognitive processing. These findings have important implications for the interpretation of gamma activity in neuropsychiatric disorders

Benefit Sanctions: Detailed Methodology

This paper, which accompanies the National Audit Office report on benefit sanctions in the UK, provides an evaluation of the labour market impact of benefit sanctions for Work Programme claimants, a large welfare-to-work programme targeting the long-term unemployed in the UK. We use rich administrative data from the Department for Work & Pensions which include information on the benefit and employment history of claimants. We exploit the random assignment of claimants to different Work Programme providers and the variation in sanction referrals, across providers, to estimate an instrumental variables model. The model allows us to identify the impact of sanctions on benefit receipt, likelihood of employment and earnings. We find that sanctions make jobs more likely for Jobseeker’s Allowance claimants but less likely for sick and disabled claimants of Employment and Support Allowance. In addition, our results on earnings suggest that Jobseeker’s Allowance claimants are often moving to jobs with shorter hours and/or lower wages. Our analysis provides the first UK evidence, using individual level data, on the impact of benefit sanctions on the labour market outcomes of sanctioned claimants and contributes to the very limited research on the impact of benefit sanctions on the labour market outcomes of claimants with disabilities

EFFECTS OF COLD STRATIFICATION AND GA3 ON GERMINATION OF ARBUTUS UNEDO SEEDS OF THREE PROVENANCES

Background: Arbutus unedo is a valuable Mediterranean shrub as an ornamental plant as well as fruit tree. Fresh fruits of A. unedo are a good source of antioxidants, of vitamins C, E and carotenoids and also are characterized by the high content of mineral elements. Materials and Methods: The effects of gibberellic acid (GA3) and cold stratification (CS) on seed germination performance were investigated in A. unedo seeds collected from three provenances in the Northern part of Greece. Seeds of each provenance were soaked in solutions of GA3 (500, 1000 or 2000 ppm) for 24 h and subsequently were subjected to CS at 3 – 5ºC for 0, 1, 2, and 3 months. Results: Non-stratified seeds of the three A. unedo provenances which were not treated with GA3 solutions exhibited very low germination. However, seed germination was significantly improved after a one-month period of CS. Similarly, the non-stratified seeds of all three provenances became non-dormant after the treatment with 2000 ppm GA3 and they germinated at high percentages. However, in untreated seeds with GA3, after a one-month CS period the seeds of the Pieria provenance exhibited higher germination percentage than that of Rodopi provenance seeds. Furthermore, in non-stratified seeds, the Pieria provenance seeds treated with GA3 germinated at higher percentages and more rapidly than those of the other two provenances. Conclusion: The results indicated that untreated seeds exhibited very low germination at 20/25ºC. However, in all three provenances seed germinability was significantly improved by a one-month period of CS or treatment of seeds with 2000 pp

Benefit Sanctions: Detailed Methodology

This paper, which accompanies the National Audit Office report on benefit sanctions in the UK, provides an evaluation of the labour market impact of benefit sanctions for Work Programme claimants, a large welfare-to-work programme targeting the long-term unemployed in the UK. We use rich administrative data from the Department for Work & Pensions which include information on the benefit and employment history of claimants. We exploit the random assignment of claimants to different Work Programme providers and the variation in sanction referrals, across providers, to estimate an instrumental variables model. The model allows us to identify the impact of sanctions on benefit receipt, likelihood of employment and earnings. We find that sanctions make jobs more likely for Jobseeker’s Allowance claimants but less likely for sick and disabled claimants of Employment and Support Allowance. In addition, our results on earnings suggest that Jobseeker’s Allowance claimants are often moving to jobs with shorter hours and/or lower wages. Our analysis provides the first UK evidence, using individual level data, on the impact of benefit sanctions on the labour market outcomes of sanctioned claimants and contributes to the very limited research on the impact of benefit sanctions on the labour market outcomes of claimants with disabilities

Association Between Resting-State Microstates and Ratings on the Amsterdam Resting-State Questionnaire

There is a gap in understanding on how physiologically observed activity is related to the subjective, internally oriented experience during resting state. Microstate analysis is a frequent approach to evaluate resting-state EEG. But the relationship of commonly observed resting-state microstates to psychological domains of resting is not clear. The Amsterdam Resting-State Questionnaire (ARSQ) was recently introduced, offering an effective way to quantify subjective states after a period of resting and associate these quantifiers to psychological and physiological variables. In a sample of 94 healthy volunteers who participated in closed-eyes 5 min resting session with concurrent EEG recording and subsequent filling of the ARSQ we evaluated parameters of microstate Classes A, B, C, D. We showed a moderate negative association between contribution (r = -0.40) of Class C and experienced somatic awareness (SA). The negative correlation between Class C and SA seems reasonable as Class C becomes more dominant when connections to contextual information (and bodily sensations as assessed with SA) are loosened (in reduced attention states, during sleep, hypnosis, or psychosis). We suggest that the use of questionnaires such as the ARSQ is helpful in exploring the variation of resting-state EEG parameters and its relationship to variation in sensory and non-sensory experiences