Entropically stabilized local dipole formation in lead chalcogenides     

Božin ES  Malliakas CD  Souvatzis P  Proffen T  Spaldin NA  Kanatzidis MG  Billinge SJ 《Science (New York, N.Y.)》2010,330(6011):1660-1663

We report the observation of local structural dipoles that emerge from an undistorted ground state on warming, in contrast to conventional structural phase transitions in which distortions emerge on cooling. Using experimental and theoretical probes of the local structure, we demonstrate this behavior in binary lead chalcogenides, which were believed to adopt the ideal, undistorted rock-salt structure at all temperatures. The behavior is consistent with a simple thermodynamic model in which the emerging dipoles are stabilized in the disordered state at high temperature due to the extra configurational entropy despite the fact that the undistorted structure has lower internal energy. Our findings shed light on the anomalous electronic and thermoelectric properties of the lead chalcogenides. Similar searches may show that the phenomenon is more widespread.  相似文献   

The effects of environmental enrichment and transport stress on the weights of lymphoid organs,cell‐mediated immune response,heterophil functions and antibody production in laying hens          下载免费PDF全文

Erdal Matur  İbrahim Akyazi  Evren Eraslan  Elif Ergul Ekiz  Hüseyin Eseceli  Mehmet Keten  Kemal Metiner  Deniz Aktaran Bala 《Animal Science Journal》2016,87(2):284-292

The effects of environmental enrichment and transport stress on the immune system were investigated in laying hens. A total of 48 1‐day‐old chickens were used, half of the chickens were reared in conventional cages (RCC) and the rest in enriched cages (REC). Transport stress was applied in the 17th week. Liver weight decreased, spleen and bursa of Fabricius weights, white blood cell count, CD4+ and CD8+ cell proportions increased due to the transport. Environmental enrichment significantly increased antibody production and tended to increase monocyte percentage and CD8+ cell proportion. The effect of transport on, heterophil (H) and lymphocyte (L) percentages was not significant in RCC chickens. While heterophil percentage and H:L ratio increased, lymphocyte percentage decreased in REC chickens subjected to transport. Transport stress increased heterophil functions both in REC and RCC chickens, but the increase was higher in REC hens than in RCC hens. In conclusion, although environmental enrichment did not neutralize the effect of transport on lymphoid organs, it activated the non‐specific immune system, cellular and the humoral branches of the specific immune system by increasing heterophil functions, CD8+ cells and antibody production, respectively. Therefore, environmental enrichment suggested for improving animal welfare may also be beneficial to improve the immune system of birds exposed to stress.  相似文献   

Clinicopathological findings of an episode of mycotoxicosis in horses     

R. K. Dedar  N. Virmani  P. A. Bala  J. Singh  R. K. Vaid  R. A. Legha  B. N. Tripathi 《Equine Veterinary Education》2019,31(5):236-241

This report of mycotoxicosis in horses describes the clinical signs, post-mortem findings, histopathological findings and prognosis following the accidental feeding of mycotoxin contaminated fodder to the horses at a farm over a 3-year period. Variable clinical signs viz. weight loss, height retardation in foals, episodes of sudden weakness and staggering gait, ulceration in the oral cavity and at mucocutaneous junctions, yawning, decreased appetite to complete anorexia, rectal prolapse, and failure of blood clotting were observed in many horses at an organised equine farm over a period of 2–3 years. Post-mortem examination of these cases revealed liver cirrhosis and pathological changes in other organs too. On examination of the fodder, it was observed that pearl millet fodder fed to the animals had ergot infestation. On laboratory investigation of the fodder, aflatoxins levels ranged from 24 ppb to 70 ppb in pearl millet fodder. The analysis eventually led to discontinuation of the pearl millet fodder. On follow-up for 2 years, no new cases of hepatic cirrhosis were seen. Most of the horses at the farm including those that had shown high levels of serum gamma glutamyl transferase (GGT) and weight loss, recovered completely. The present episode demonstrates that there is a need for regular monitoring of cereal fodders of horses in subtropical and tropical areas to avoid mycotoxicosis. In the present episode, monitoring serum/plasma GGT levels was found to be a sensitive biochemical indicator to identify liver damage caused by mycotoxins.  相似文献   

Phytoplasma infection may affect morphology,regeneration and pyrethrin content in pyrethrum shoot culture     

J. Ambrožič-Dolinšek  M. Camloh  J. Žel  Maja Kovač  Maja Ravnikar  L. Carraro  N. Petrovič 《Scientia Horticulturae》2008

The aim of the work was to infect pyrethrum (Tanacetum cinerariifolium (Trevir.) Schultz-Bip.), an important secondary metabolite pyrethrin producing plant, with MA phytoplasma (16S rRNA group III, subgroup B) to initiate tissue culture of phytoplasma-infected plants, and to examine possible effects of infection on pyrethrin content, morphology, and regenerative capacity in shoot culture.  相似文献   

Selection of fecund and chemically valuable clones of thyme (Thymus) species growing wild in Lithuania     

Kristina Ložienė 《Industrial Crops and Products》2009,29(2-3):502-508

The high infraspecific chemical and morphological polymorphism is characteristic for species of genus thyme (Thymus L.). This characteristic can be subservient to the selection of valuable clones from natural habitats. The objective of the present study was to select valuable Thyme clones from native flora of Lithuania according to the productivity of biomass and chemical composition of essential oils for the cultivation. Two Thymus species, namely large thyme (T. pulegioides L.) and wild thyme (T. serpyllum L.), grow wild in Lithuania and other Baltic States (Latvia and Estonia). Was established that T. pulegioides is more suitable for the cultivation than T. serpyllum, because can grow more dried total biomass (up to 3 times), are higher (2.8 times) and synthesize higher amount of essential oils with significant amounts of such biologically active compounds as the thymol, carvacrol, geraniol or linalool. Four most fecund clones of T. pulegioides (the total biomass of dried plant 29–45 g, the amount of essential oil in whole plant 0.5–0.7%) were selected which accumulate the highest amounts of thymol (up to 26.1%), carvacrol (up to 31.0%), geraniol (up to 45.0%) and linalool (up to 80.3%). The cultivation of these clones enables to get the high yield of biomass and chemically homogeneous herbal raw material of desirable chemical composition for the phytomedicines and phytocosmetics.  相似文献   

Distribution and abundance of small rodents in Croatian forests     

J. Margaletić  M. Božić  M. Grubešić  M. Glavaš  W. Bäumler 《Journal of pest science》2005,78(2):99-103

The relative abundance and the population development of small rodents were investigated on 17 sites in Croatian forests from September 1999 through June 2003. Common snap traps were set for two or three nights along transect lines in different forest types. In 27,598 trap–nights, 2,151 specimens were trapped. Small rodents were present in up to 45% of the traps in pedunculate oak forests dominated by Quercus robur L. In common beech forests with a predominance of Fagus sylvatica L., the percentage of occupied traps reached 59%. At most sites the following species were dominant:Clethrionomys glareolus Schr., Apodemus agrarius Pall. and A. flavicollis Melch. Additionally, in a forest community of Carpino betuli-Quercetum roboris typicum R., the absolute number of small rodents was calculated by means of the standard minimum method. The minimum rodent density was observed in April 2003 with 11.63 n/ha (number of specimens per hectare). The maximum was reached in March 2001 with 82.03 n/ha. Near the same site, the absolute number of the small rodent population was estimated using the Y method in spring 2001 as approximately 101.34 n/ha. In general, the abundance of small rodents was dependent on the forest seed crop.  相似文献   

Larssoniella duplicati n.sp. (Microsporidia, Unikaryonidae), a newly described pathogen infecting the double-spined spruce bark beetle, Ips duplicatus (Coleoptera, Scolytidae) in the Czech Republic     

J. Weiser  J. Holuša  Z. Žižka 《Journal of pest science》2006,79(3):127-135

Larssoniella duplicati n.sp. infects the midgut muscularis, the Malpighian tubules, and the ovaries of adult Ips duplicatus (Sahlb.) in the Czech Republic. The microsporidian attacks up to 50% of the population. Oval spores of two sizes, 3–3.5×1.5–2 and 2–2.5×1.5 μm have the polar filament coiled in 6/7 coils, representing primary and environmental spores, respectively. In early sporogony the young spores produce long electron dense threads and tubules of secretions, which remain fixed around the spore and avoid their free release during dissection of infected hosts. The microsporidian was not found in associated bark beetles such as Ips typographus (L.), or I. amitinus (Eichh.) and others.  相似文献   

Intra-increment circumferential variation in tracheid length as a basis for sampling genetically superior trees of deodar (Cedrus deodara (Roxb.) Loud.)     

M. K. Seth  M. Bala  C. Lal 《Wood Science and Technology》1987,21(4):293-301

Summary Intra-increment circumferential variation in tracheid length at breast-height in deodar (Cedrus deodara (Roxb.) Loud. vern. diar) has been studied with the main objective of evolving an efficient sampling procedure for the purpose of comparing tracheid length amongst individual trees of forest stands. It has been studied in five sampling strata namely: whole-annual ring, whole-earlywood, whole-latewood, first-firmed earlywood and last-formed latewood. Tracheid length shows significant circumferential variation in whole-annual ring, whole-earlywood, whole-latewood and last-formed latewood. However, when the mean tracheid length of two opposite directions is compared with the mean tracheid length of eight cardinal directions in these sampling strata, then no significant difference is observed. First-formed stratum of an annual ring exhibits statistically consistent values around the circumference and thus sampling from any random radial direction can serve the purpose for the comparison of inherent values of tracheid length amongst the deodar trees.The financial assistance given by Himachal Pradesh University as H.P.U. Junior Research Fellowship to second author is highly acknowledged  相似文献   

Combinations of several insecticides used for integrated control of Colorado potato beetle (Leptinotarsa decemlineata, Say., Coleoptera: Chrysomelidae)     

J. Igrc Barčić  R. Bažok  S. Bezjak  T. Gotlin Čuljak  J. Barčić 《Journal of pest science》2006,79(4):223-232

The Colorado potato beetle (Leptinotarsa decemlineata Say.) (CPB) is the main potato pest in Croatia. The main problems in CPB control are related to a number of treatments and resistance development. In order to investigate the efficacy of combinations a reduced dose of spinosad (33% of the full doses) with the reduced doses (33% of full doses) of B.t.t., neem and pyrethrin against CPB larvae, 3-year field trials and one laboratory trial were conducted. Joint actions of the insecticides in combinations were analyzed. The CPB attack on experimental fields in all 3 years of investigation was high to moderate. In 2001 the maximum number of larvae on untreated plots was 11.7 larvae per plant, while in 2002 and 2003 it was lower, 5.5 and 6.1 larvae/plant, respectively. The efficacy obtained with a full dose of B.t.t. reached 75% in the field, and 78% in the laboratory trial. The residual efficacy of a full dose of B.t.t. lasted 7–10 days. The application of both, full and reduced doses of B.t.t., did not result in a significant yield increase. The results indicate that only one treatment with B.t.t. insecticide alone is not enough for efficient protection of potato against the attack of CPB larvae. The application of neem resulted in an efficacy of between 54 and 87.9%. The residual activity of neem was too short to ensure significant yield increase in 2 out of 3 years of the investigation. The application of a full dose of pyrethrin ensured an efficacy of between 86 and 89% with residual activity of 7–10 days. Only in the trial in 2003 significant yield increase (40% higher than untreated control) after the application of a full dose of pyrethin was recorded. The application of both, full and reduced doses of spinosad resulted in very high efficacy (over 90%), with residual activity between 10 and 20 days. The application of spinosad resulted in a significant yield increase in 2003, both in full and reduced doses, and in 2001 in the full dose (the reduced dose was not tested alone in 2001). High efficacy of the reduced dose of spinosad indicated its high biological activity and possibility for the reduction of the recommended dose. However, applications of combinations of insecticides in reduced doses (spinosad with B.t.t., neem and pyrethrin) resulted in efficacies of over 97% with residual activity of up to 21 days. Significant yield increase was noted after the application of the combinations of spinosad with B.t.t. and pyrethrin. The results of the laboratory trial confirmed the results of field trials. The joint action of insecticides was mainly described as independent synergism. It can be concluded that applied combinations are suitable in IPM in potato.  相似文献   

Groundwater and Light Conditions as Factors in the Survival of Pedunculate Oak (Quercus Robur L.) Seedlings     

Matjaž Čater  Franc Batič 《European Journal of Forest Research》2006,125(4):419-426

A noticeable decline and physiological weakening of pedunculate oak (Quercus robur L.) has been recorded in the past decade in lowland parts of Slovenia. The triggers were dry climate, unfavourable precipitation patterns and human influence that brought about changes in watercourses and water tables. Regeneration and future management of this tree species is therefore questionable. To define a critical groundwater table which would permit successful regeneration, planted and naturally grown seedlings were compared in two forests differing in the degree of decline and physiological weakness of adult pedunculate oak trees. Comparison of stomatal conductance and pre-dawn water potential (PWP) showed differences of seedlings between and within forest complexes. Stomatal conductance dropped below 100 mmol m⁻² s⁻¹ at PWP values below −1.0 MPa, while closure of stomata was caused by a PWP between −1.6 and −1.9 MPa. Increased water stress equalized photosynthetic yield in both natural and planted oaks below −1.4 MPa.  相似文献