Midline Cysts of Colliculus Seminalis Causing Ejaculatory Problems in Stallions

Cystic structures are often seen during ultrasound examination of the internal genitalia of stallions. They are located between the ampullae of deferent ducts, either within the urogenital fold, or under the isthmus of the prostate (uterus masculinus). Occasionally, cystic dilatations are also found more caudally, behind the prostate, at the colliculus seminalis (urethral cyst, utriculus masculinus). These cysts are detected less frequently during routine examinations, possibly because of the fact that this area is screened less carefully for the pathologies than the more proximal portion of the internal reproductive tract of stallions. We have recently noticed that many stallions with ejaculatory problems have large cysts at the colliculus seminalis. This article describes the typical clinical presentation of these cases, diagnostic procedures, and management. In addition, we discuss the discrepancies in the currently used terminology pertinent to this condition, as well as introducing a new term, which seems to best describe the root cause of this disorder. Finally, this article presents new diagnostic and therapeutic options used in human medicine in similar cases, and proposes to investigate the applications of these methods in veterinary medicine.     

Dissolved organic carbon and nitrogen leaching from Scots pine, Norway spruce and silver birch stands in southern Sweden

The effects of three common tree species - Scots pine, Norway spruce and silver birch - on leaching of dissolved organic carbon and dissolved nitrogen were studied in an experimental forest with podzolised soils in southern Sweden. We analyzed soil water collected with lysimeters and modeled water fluxes to estimate dissolved C and N fluxes. Specific UV absorbance (SUVA) was analyzed to get information about the quality of dissolved organic matter leached from the different stands. Under the O horizon, DOC concentrations and fluxes in the birch stands were lower than in the spruce and pine stands; annual fluxes were 21 g m⁻² y⁻¹ for birch and 38 g m⁻² y⁻¹ and 37 g C m⁻² y⁻¹ for spruce and pine, respectively. Under the B horizon, annual fluxes for all tree species ranged between 3 and 5 g C m⁻² y⁻¹, implying greater loss of DOC in the mineral soil in the coniferous stands than in the birch stands. We did not find any effect of tree species on the quality of the dissolved organic matter, as measured by SUVA, indicating that the chemical composition of the organic matter was similar in leachates from all three tree species. Substantial amounts of nitrogen was leached out of the soil profile at the bottom of the B horizon from the pine and birch stands, whereas the spruce stands seemed to retain most of the nitrogen in the soil. These differences in N leaching have implications for soil N budgets.     

Length and classification of natural and created forest edges in boreal landscapes throughout northern Sweden

Forest edges have numerous implications for structure and function of forest ecosystems. Previous studies on edge quantity have used broad classifications. However, edge influence is driven by the contrast in vegetation structure between adjoining ecosystems, and thus we need detailed site-specific data to assess the role of edges in forests. We studied the variability of sharp edges in 28 boreal landscapes (4 km × 4 km) across an 830 km gradient throughout northern Sweden. Our objectives were: (1) to compare the length of natural and created edges, (2) to classify edges in detail by edge origin, maintenance and forest attributes, and (3) to examine relationships between length of edge and landscape variables. Data were collected using stereo-interpretation of high spatial resolution colour infrared aerial photographs, in combination with line intersect sampling and plots. The length of edge varied from 12 to 102 m ha⁻¹ among landscapes, with an overall mean of 54 m ha⁻¹. Created edges dominated most landscapes (mean 33 m ha⁻¹) and had greater variability than natural edges (mean 21 m ha⁻¹). Maintained edges (e.g. roads, agricultural land) were more abundant than regenerating edges caused by logging. Thirty percent of total edges adjoined narrow linear features. Seventy percent adjoined wider patches and showed high variability (35 classes). Overall, high-contrast edges towards mature forest dominated, i.e. ones that may experience strong edge influence. The amount of edge increased with percent of landscape affected by disturbance, and decreased with latitude and elevation. This study shows that edges are both abundant and highly variable in boreal forests and that forestry is the main driver behind edge creation. Detailed classification of edges based on site-specific forest and patch attributes may help to estimate edge influence at landscape level, and can guide experimental design for examining the impact of edges on structure and function of forest ecosystems.     

Hydrogeochemistry of a stream draining sulfide-bearing postglacial sediments in Finland

The influence of hydrological conditions and overburden type on the stream-water quality in a catchment effected by fine-grained sulfide-bearing sediments was studied. Water samples for measurement of pH and electric conductivity were collected at 16 sites along the main course of the stream during autumn and spring high water flow and during low and intermediate water flow. On one occasion (spring high-water flow) samples for analysis of total organic carbon were collected at these sites. Seventeen water samples for analyses of chemical elements (ICP-MS and ICP-AES) were taken within the catchment basin during autumn high water flow. The pH and conductivity of snow, and the geochemistry of the sulfide sediments were also studied. The occurrence of fine-grained sediments within the catchment was estimated from topographic and geologic maps and by visit to areas were the overburden type could not be determined from the maps. The hydrological conditions had a strong influence on the water quality. During high water flow in spring and autumn the concentrations of ionic components (conductivity) and hydrogen ions in the stream water were high, while the concentrations were much lower during low and intermediate water flow and when the ground was frozen. Extensive leaching of the sulfide-bearing sediments, which had higher contents of S and metals than the fine fraction of till in the study area, resulted in elevated contents of Li, Ni, Zn, Co, B, Al, Mg, U, Sr, Ca, K and Na in the stream water during autumn high water flow. The contents of Cr, Ba, Pb, Si and Fe in stream water were not much influenced by the type of overburden, while V was depleted in drainage waters from the sulfide sediments. Humic substances flocculated in the water in the middle section of the stream, which may have been caused by di- and trivalent metal cations leached in large quantities from the oxidizing sulfide sediments.     

Choosing green sawing dimensions for Norway spruce from stochastic simulations

The high accuracy of log positioning and the stability of saw blades in breakdown machinery in modern sawmills have reduced the need to add margins for sawing variations. Oversize green sawing dimensions are still needed, but mainly to allow for drying shrinkage. This has put a new focus on better adapting green sawing dimensions to the shrinkage behavior of wood. In this study, a method for optimization of green sawing dimensions using stochastic simulation is presented. Normal distributions were generated for planed dry dimensions, kerf width, and target moisture content. The minimum share of boards exceeding the specified dry dimensions was decided, and deformations in boards from all positions in the cross section in a number of logs were simulated. The simulated shrinkage allowance from stochastic simulations was compared to experimental results from an industry test and to finite element results based on material data for Norway spruce. The results showed that the green width of the sawn boards should increase when the number of boards in the center yield increases. The green thickness of boards should be thinner for center boards and outer boards than for inner boards.     

Tree age effect on fine-root and leaf morphology in a silver birch forest chronosequence

The influence of forest ageing on fine-root morphology and relations between fine-root and leaf characteristics is poorly studied. The aim of this study was to analyse age-driven changes in ectomycorrhizal roots (EcM roots) and leaf morphology in a chronosequence of silver birch (Betula pendula Roth.), which would provide a better understanding of adaptation responses and acclimation capacity of tree roots and leaves. The chronosequence included six age classes (3, 6, 14, 32, 45, and 60 years.). All stands had regenerated naturally and grew in a highly productive Oxalis forest site type in Estonia. Most changes in the morphology of EcM roots and leaves of silver birch occur faster at a young age. The functional parameters—mean specific area of EcM root (SRA) and leaf specific area (SLA) as well as leaf N—decreased with age. EcM root SRA and specific root length (SRL) decreased with stand age as a result of increased mean diameter and tissue density. In age classes of 6, 14, and 32 years, the total number of dominating EcM taxa was 34, and the distribution of four different dominating EcM exploration types (contact-, short-, medium-, long-distance) was similar. We conclude that high values of SRA, SLA, and leaf N measured in young silver birch stands indicate high activity of physiological processes necessary for fast-growing young trees. A decrease of SLA and SRA and N in the chronosequence of fertile stands of silver birch is most probably caused by down-regulation of growth, affecting simultaneously leaves and fine roots.     

莺总科鸟类的系统分类进展评述(英文)

本文评述了莺总科鸟类的系统分类,并重点探讨科间、属内系统发育关系以及种级分类地位。基于已发表的 DNA 序列数据,对马岛莺科(Bernieridae)和柳莺科(Phylloscopidae)重新进行了分析。大量的分子水平的研究让我们对鸟类系统发育的认识有了很大提高。但是,由于一些主要进化分支(科)的快速分化,使得这些科之间的相互关系依然不明确。同样,分子标记和(或)鸣声及其他生活史资料在大量研究中的应用,大大提高了种级水平的分类可靠性。我们推测,随着人们运用现代的整合方法对新类群的不断研究,物种数量会不断增加。     

Degenerative joint disease (osteoarthrosis): A review with special reference to the dog

Nomenclature, incidence, etiology, pathogenesis and morphological appearance of primary and secondary osteoarthrosis (osteoarthritis) are discussed. Differences and similarities between osteoarthrosis in man and the dog are mentioned. Primary osteoarthrosis occurs in the dog but secondary osteoarthrosis seems to be more frequent. In the dog hip dysplasia, Legg-Perthes' disease, osteochondritis dissecans of the shoulder and ununited anconeal process are conditions which, among others, give rise to osteoarthrosis. Changes in the knee caused by instability after rupture of the cruciate ligaments are not those of true osteoarthrosis. There is only minimal involvement of the joint cartilage in spite of osteophyte formation, thickening of the synovium and derangement of the menisci. Clinical signs in degenerative joint disease are usually insidious in onset. For a varying period of time they are as a rule not very conspicuous. In more advanced cases the cljnical manifestations are pain, limitation of movement and muscle atrophy. The underlying changes are cartilage destruction, subchondral sclerosis, osteophytes and thickening of the synovium. In very advanced cases in man there is even attrition of bone, which clinically leads to instability and subluxation. In human coxarthrosis cyst formations are frequently seen. Etiology and pathogenesis are obscure, or only partly understood, and in animals diagnosis is sometimes difficult. There is often poor correlation between severity of radiographic changes and clinical signs. Résumé. On examine la nomenclature, l'incidence, l'étiologie, la pathogénie et l'aspect morphologique de l'ostéo-arthrose (ostéo-arthrite) primaire et secondaire. On mentionne les différences et similitudes entre I'ostéo-arthrose rencontrée chez l'homme et chez le chien. L'ostéo-arthrose primaire se rencontre chez le chien, mais les cas d'ostéo-arthrose secondaire sont plus fréquents. Chez le chien, la dysplasie de la hanche, la maladie de Legg-Perthes, l'ostéochondrite disséquante de l'épaule et I'apophyse anconée disloquée sont des états qui, entre autres, engendrent l'ostéo-arthrose. Des transformations du genou, causées par une instabilité après rupture des ligaments croisés, ne sont pas celles de I'ostéo-arthrose proprement dite. Le rôle du cartilage articulaire n'est que minime, malgré l'apparition d'ostéophytes, l'épaississement des membranes synoviales et les troubles des ménisqua. Les signes cliniques des maladies articulaires dégéntratives sont généralement insidieux au départ. Pendant une période de temps variable, ils ne sont d'ordinaire pas très marqués. Pour les cas plus graves, les manifestations cliniques sont la douleur, la restriction des mouvements et l'atrophie musculaire. Les transformations qui sont à base de ces manifestations comprennent: destruction du cartilage, sclérose sous-cartilagineuse, ostéophytes et épaississement des membranes synoviales. Si chez l'homme, l'etat est très grave, on assiste même à l'attrition des os, qui, du point de vue clinique, mène à I'instabilité et la subluxation. En cas de coxarthrose chez l'homme, on observe fréquemment la formation de kystes. On ne connaît pas bien et ne comprend que partiellement l'étiologie et la pathogénie de ces maladies et, chez les animaux, le diagnostic est beaucoup plus difficile à établir. Très souvent on n'obtient pas de bonne corrélation entre I'importance des changements radiographiques et les signes cliniques. Zusammenfassung. Nomenklatur, Häufigkeit, Ätiologie, Pathogenese und morphologisches Aussehen von primärer und sekundärer Osteoarthrosis (Osteoarthritis) werden besprochen. Unterschiede und Ähnlichkeiten zwischen Osteoarthrosis des Menschen und des Hundes werden erwähnt. Primäre Osteoarthrosis tritt beim Hund auf, jedoch scheint die sekundäre Osteoarthrosis häufiger zu sein. Beim Hund sind Hüftendysplasie, Legg-Perthessche Krankheit, Osteochondritis dissecans der Schulter und unvereinigte anconeale Prozesse Zustände, die unter anderem zu Osteoarthrosis führen. Verändemngen am Knie, die durch Instabilität nach Ruptur der Kreuzbänder verursacht werden, sind nicht die echter Osteoarthrosis. Der Gelenkknorpel ist nur minimal betroffen, trotz Osteophytenbildung, Verdickung der Synovia und Meniskusverlagerung. Klinische Zeichen degenerativer Gelenkerkrankungen sind gewöhnlich anfangs mehrdeutig. In der Regel sind sie unterschiedlich lange nicht sehr auffällig. In fortgeschritteneren Fällen sind die klinischen Merkmale Schmerz, Bewegungsbehinderung und Muskelatrophie. Die zugrundeliegenden Veränderungen sind Knorpelzerstörung, subchondrale Sklerose, Osteophyten und eine Verdickung der Synovia. In sehr fortgeschrittenen Fällen beim Menschen tritt selbst Knochenabnutzung auf, die klinisch zu Instabilität und Subluxation führt. Bei Coxarthrosis des Menschen wird häufig Zystenbildung beobachtet. Ätiologie und Pathogenese sind dunkel oder nur teilweise aufgeklärt, und bei Tieren ist die Diagnose viel schwieriger. Oft besteht eine schlechte Korrelation zwischen der Schwere der radiographischen Verändemngen und den klinischen Zeichen.     

Rare earth intensifying screens in veterinary radiology

Radiation dose to personnel and low capacity X–ray equipment are obstacles to the optimal use of veterinary radiology. In order to find means to lower radiation dose and improve the quality of the radiographic image in veterinary radiology the authors have tested the so–called rare earth intensifying screens under experimental and clinical conditions. Of the basis of their findings they recommend the use of predominantly green light–emitting screen with lanthanum oxysulphide crystals activated with terbium, in combination with orthochromatic film. This combination was shown to give the best ratio image–screen noise. Considerable dose reduction was obtained with this system, and the image quality improved due to less blurring by motion.