Identifying DOC gains and losses during a 20-year record in the Trout Beck catchment,Moor House,UK

The turnover of organic carbon in rivers could represent a large source of greenhouse gases to the atmosphere and studies have suggested that of the order of 70% of the dissolved organic carbon exported from soils could be lost in rivers before it flows to continental seas. The Environmental Change Network (ECN) monitoring of the dominantly peat-covered Trout Beck catchment within the Moor House site enabled the amount of dissolved organic carbon (DOC) lost within a stream over a 20-year period to be estimated. The study compared DOC concentrations of precipitation, shallow and deep soil waters with those at the catchment outlet. The mass balance between source and outlet was reconstructed by two methods: a single conservative tracer; and based upon a principal component analysis (PCA) using multiple tracers. The study showed the two methods had different outcomes, with the PCA showing a DOC gain and the single tracer showing a DOC loss. The DOC gain was attributed to an unmeasured groundwater contribution that dominates when the river discharge is lower. The DOC loss was related to the in-stream residence time, the soil temperature and month of the year, with longer in-stream residence times, warmer soils and summer months having larger DOC losses. The single tracer study suggested a 10 year average loss of 8.77 g C m⁻² year⁻¹, which is 33.1 g CO_2eq m⁻² year⁻¹, or 29% of the DOC flux from the source over a mean in-stream residence time of 4.33 h.     

Biodiversity and the Heterogeneous Disturbance Regime on Military Training Lands

Disproportionately large numbers of threatened and endangered species and unusually high biodiversity occur on active and former military training areas. Although this may seem paradoxical given the apparently destructive nature of military training, an evaluation of the nature and extent of the disturbances is enlightening. Military training frequently produces heterogeneous landscapes. Large portions of military training areas remain virtually untouched, favoring disturbance‐averse species; other portions are heavily disturbed, favoring disturbance‐dependent species. The rich habitat mosaics include the two extremes as well as the continua of disturbance and succession between them, thus providing suitable habitat for a very large number of species with widely varying habitat requirements. To explain the phenomenon, a heterogeneous disturbance hypothesis is proposed which suggests that biodiversity is maximized where multiple kinds, frequencies, severities, periodicities, sizes, shapes, and/or durations of disturbance occur concomitantly on a landscape in a spatially and temporally distributed fashion. The enhanced biodiversity occurring on active and former military training areas illustrates the need for restoration ecologists to restore or maintain an appropriate heterogeneous disturbance regime when attempting to restore ecosystem function and biodiversity.     

Egyptian tortoise conservation: A community‐based,field research program developed from a study on a captive population

Local community participation and ex situ conservation has the potential to assist the recovery of the endangered Egyptian tortoise, Testudo kleinmanni. We initiated an in situ community‐based conservation and research program from a captive population of T. kleinmanni. We used a captive population of the Egyptian tortoise to train a member of the local community as a research technician and used his indigenous tracking skills and knowledge of the area to collect activity and dietary data on 28 captive tortoises. We overcame problems with illiteracy by creating a data sheet based on symbols and numbers. This data sheet allowed us to use the indigenous knowledge of various people from the community, and employ them in the future. Our local community approach to data collection, in conjunction with a craft program, made the conservation of the Egyptian tortoise more rewarding to the local community by providing a more sustainable form of income than collecting animals for the pet trade. Our multidimensional approach (local community participation as research technicians, craft program, and trust building) for gaining local support eventually led to the rediscovery of wild Egyptian tortoises in North Sinai, which was significant, as this species was presumed extinct in Egypt. We have now shifted our focus to in situ conservation, using the research and local capacity building template developed from this captive population study. Our template can be used by zoos and conservation organizations with small budgets and collections of native species in natural habitats to create similar captive research programs that can be applied to in situ conservation. Zoo Biol 26:397–406, 2007. © 2007 Wiley‐Liss, Inc.     

Temporal and spatial trends in heavy metal concentrations in the marine mussel Mytilus edulis from the Western Scheldt estuary (The Netherlands)

Since the first North Sea Conference (1984, Bremen), all countries bordering the North Sea made commitments to reduce discharge of hazardous substances into the North Sea. From Belgium and The Netherlands, large reductions (upto 90) in heavy metal emissions from land-based sources have been reported between 1985 and 2000. Recently, some studies in the Western Scheldt estuary (WS) have shown that total metal concentration in the water, sediments and suspended particles have decreased compared to levels in the 70s. However, data on aquatic organisms is still very limited and it is therefore difficult to confirm whether the reductions in pollution input and generally improving water quality in the WS have a corresponding impact on the levels of heavy metals in aquatic organisms. The current study measured metal concentrations in the soft tissues of mussels, Mytilus edulis (known to be good indicators of environmental metal pollution) during the period 1996–2002. Spatial (salinity and pollution gradients), temporal and seasonal variations were also studied. Results showed a down-stream decreasing trend for the metals studied (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) during all sampling campaigns. There was also a significant seasonal effect on tissue metal concentrations, with a peak observed around spring in both WS and the nearby less polluted Eastern Scheldt (ES). On temporal trends, a clear drop of metals in mussels was observed in the early 80s coinciding with the start of the efforts to reduce chemical pollution input into the North Sea. Since those early reductions, metal concentrations in mussels generally remained unchanged upto mid 90s. However, in recent times metal concentration in mussels have increased significantly, for example Cd in 2002 was almost 10 times the values in 1983 and similar to levels seen during the peak in the 70s. Other metals also increased in the 90s also reaching levels seen in the 70s. As there is no indication of recent increase in metal input into the estuary, we suggest that increased metal concentrations observed in mussels in recent years especially in the upper estuary are most likely a result of changes in physical and chemical speciation and metal bioavailability. Such changes may be caused by changes in some water quality parameters in the estuary (i.e. increased dissolved oxygen, concentration of organic matter), resulting in conditions that favour releases of sediment-bound metals into the water column. The relationship between metal content and season showed very similar annual profiles in the polluted WS and less polluted ES. Thus, seasonal variations in metal concentrations appear to be largely controlled by biological processes, while total body burdens are dependent on environmental levels and bioavailability.     

Prevalencia y etiopatogenia del dolor oncológico neuropático en el anciano

The prevalence of neuropathic pain is difficult to estimate as most studies evaluating chronic pain do not differentiate neuropathic from nociceptive pain. There are only a few studies of neuropathic pain in the elderly, specifically in the oncology population. This article is a non-systematic review of the relevant evidence on the prevalence and aetiopathogenesis of neuropathic cancer pain in the elderly.     

Nanoparticles as tools to study and control stem cells

The use of nanoparticles in stem cell research is relatively recent, although very significant in the last 5 years with the publication of about 400 papers. The recent advances in the preparation of some nanomaterials, growing awareness of material science and tissue engineering researchers regarding the potential of stem cells for regenerative medicine, and advances in stem cell biology have contributed towards the boost of this research field in the last few years. Most of the research has been focused in the development of new nanoparticles for stem cell imaging; however, these nanoparticles have several potential applications such as intracellular drug carriers to control stem cell differentiation and biosensors to monitor in real time the intracellular levels of relevant biomolecules/enzymes. This review examines recent advances in the use of nanoparticles for stem cell tracking, differentiation and biosensing. We further discuss their utility and the potential concerns regarding their cytotoxicity. J. Cell. Biochem. 108: 746–752, 2009. © 2009 Wiley‐Liss, Inc.