Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives

Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown. Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables. Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies. We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes. Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species

Case Report Large Retroperitoneal Liposarcoma Diagnosed upon Radiological Evaluation of Mild Right-Sided Inguinal Hernia

While inguinal hernia is common in the primary care office, the differential diagnosis is extensive and includes infectious, inflammatory and neoplastic processes. Varicocele is another frequent, generally benign condition which occasionally reflects serious disease entities. Left-sided or bilateral varicoceles account for the overwhelming majority of varicoceles because the left gonadal vein drains into the left renal vein in contrast to the right gonadal vein, which drains directly into the inferior vena cava, thus making left-sided or bilateral venous congestion more likely. Presence of an uncommon unilateral right-sided varicocele thus warrants further radiological workup, in particular CT abdomen and pelvis, to evaluate for retroperitoneal pathology. We describe a case in which appropriate use of a variety of imaging modalities including testicular ultrasound and CT led to an important diagnosis of a large, well-differentiated liposarcoma in the right retroperitoneum of a patient with a right-sided groin mass

How do MNC R&D laboratory roles affect employee international assignments?

Research and development (R&D) employees are important human resources for multinational corporations (MNCs) as they are the driving force behind the advancement of innovative ideas and products. International assignments of these employees can be a unique way to upgrade their expertise; allowing them to effectively recombine their unique human resources to progress existing knowledge and advance new ones. This study aims to investigate the effect of the roles of R&D laboratories in which these employees work on the international assignments they undertake. We categorise R&D laboratory roles into those of the support laboratory, the locally integrated laboratory and the internationally interdependent laboratory. Based on the theory of resource recombinations, we hypothesise that R&D employees in support laboratories are not likely to assume international assignments, whereas those in locally integrated and internationally interdependent laboratories are likely to assume international assignments. The empirical evidence, which draws from research conducted on 559 professionals in 66 MNC subsidiaries based in Greece, provides support to our hypotheses. The resource recombinations theory that extends the resource based view can effectively illuminate the international assignment field. Also, research may provide more emphasis on the close work context of R&D scientists rather than analyse their demographic characteristics, the latter being the focus of scholarly practice hitherto

Ocena właściwości tribologicznych polietylenu UHMW w warunkach pracy na sucho i ze smarowaniem

The aim of the study was to evaluate tribological properties of ultra-high-molecular-weight polyethylene (UHMWPE). This study concerns the areas of both mechanical and biomechanical application fields, including chain guides and knee or hip joint liner replacement. The presented paper describes conducted research on tribological properties of UHMWPE with tribological testing station UMT-2 Bruker. This testing station is capable of conducting tribological tests of ferrous, non-ferrous metals, plastics, ceramics, composites, and various types of coatings, under both "dry" and liquid and solid lubricating agents. Tests were performed under various conditions, differing in relative speed and the load of interacting frictional pair. Moreover, test duration and the performed number of cycles were considered.Celem pracy jest ocena właściwości tribologicznych polietylenu wielocząstkowego w odniesieniu do aplikacji mechanicznych oraz biomedycznych, m.in. prowadnic w przekładniach łańcuchowych oraz elementów pośrednich (przekładek) endoprotez stawowych. W pracy przedstawiono badania mające na celu kompleksową ocenę właściwości tribologicznych UHMWPE za pomocą wielopróbkowego stanowiska badawczego UMT-2 Bruker. Urządzenie pozwala na badania tribologiczne materiałów żelaznych, nieżelaznych, tworzyw sztucznych, ceramiki, kompozytów, jak i różnego rodzaju powłok w warunkach „na sucho” oraz smarowania środkami ciekłymi i stałymi. Badania tribologiczne prowadzono w różnych warunkach, tj. przy zadanej prędkości względnej współpracującej pary ciernej, siły obciążająca parę trącą, temperatury, określonej częstotliwości, ilość przeprowadzanych cykli pracy oraz przerwy między nimi z zastosowaniem różnych środków smarujących