First fossil evidence of an “interglacial refugium” in the Pyrenean region

A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.     

ASSESSING RELATIVE RISKS TO AQUATIC ECOSYSTEMS: A MID-APPALACHIAN CASE STUDY1

ABSTRACT: Aquatic monitoring aims to assess the condition of aquatic habitats and biota. To make statements about condition, the range of human activities and the risks they pose to aquatic ecosystems must be identified. Assessing relative risk and placing sample sites on a human disturbance gradient is necessary for interpreting biological response and distinguishing human disturbance from natural controls in aquatic systems. We describe a process that uses readily available sources, such as topographic maps, aerial photographs, and field information, to identify and prioritize stream reach and watershed stressors for 102 streams in the mid-Appalachian region of the United States. All perceptible human alterations to riparian and upland areas along with their number, type, intensity, and extent of impact were recorded and ranked; a relative risk index was developed to assign scores to the watersheds. The resulting risk index scores were consistent with measures of stream condition based on water chemistry and benthic macroinvertebrates. The risk index gives a cost-effective, regional picture of the relative risk of impairment to aquatic ecosystems in the mid-Appalachian region of the USA and could be modified for other regions or ecosystem types.     

A rare case of isolated right atrial enlargement and TBX5 mutation associated with Holt–Oram syndrome

Holt–Oram syndrome or atriodigital dysplasia is commonly associated with cardiac malformations, most often with defects of the muscular septum. We describe the case of a fetus referred for fetal cardiology evaluation in the setting of right atrial enlargement without tricuspid valve abnormalities with small muscular VSDs, and without other significant cardiac lesions. On serial fetal echocardiograms, isolated right atrial enlargement was persistent as was relative fetal bradycardia without apparent AV block or other signs of abnormal conduction. Limb or other anatomic abnormalities were also not visualized on prenatal scans. A postnatal diagnosis of Holt–Oram Syndrome was made. In the setting of isolated right atrial enlargement, we suggest a comprehensive sonographic search for upper limb abnormalities as well as genetic evaluation.     

Biomass and Nutrient Dynamics of Restored Neotropical Forests

Restoring species-rich tropical forests is an important activity because it helps mitigate land deforestation and degradation. However, scientific understanding of the ecological processes responsible for forest restoration is poor. We review the literature to synthesize the current state of understanding of tropical forest restoration from a biogeochemical point of view. Aboveground biomass and soil carbon accumulation of restored tropical forests are a function of age, climate, and past land use. Restored forests in wet life zones accumulate more biomass than those in moist or dry life zones. Forests restored on degraded sites accumulate less aboveground biomass than forests restored on pastures or agricultural land. Rates of aboveground biomass accumulation in restored forests are lower than during natural succession, particularly during the first decades of forest establishment. Rates of litterfall, biomass production, soil carbon accumulation, and nutrient accumulation peak during the first few decades of restored forest establishment and decline in mature stages. Changes in species composition and canopy closure influence the rate of primary productivity of older restored stands. Species composition also influences the rate and concentration of nutrient return to the forest floor. The ratio of primary productivity to biomass is high in young restored forests and low in mature stands irrespective of climate. The ratio is low when past land use has little effect on biomass accumulation, and high when past land uses depresses biomass accumulation. This effect is due to a high rate of litterfall in restored forests, which helps restore soil by circulating more nutrients and biomass per unit biomass accumulated in the stand. The degree of site degradation and propagule availability dictates the establishment and growth of tree species. Reestablishment of forest conditions and the enrichment of sites by plant and animal species invasions lead to faster rates of succession, aboveground primary productivity, and biomass accumulation in restored forests. Our review demonstrates that nutrient cycling pathways and nutrient use efficiency are critical for interpreting the suitability of tree species to different conditions in forest stands undergoing restoration.     

Ionizing radiation for maternal medical indications

Ionizing radiation should be considered an avoidable exposure although all pregnant women receive some radiation from their environment. The potential effect of ionizing radiation on the fetus is determined by the dose and the timing of the exposure with growing interest in the potential risks of transgenerational effects of radiation as an epigenetic phenomenon. High dosage exposure is very unlikely in routine situations such as occupational, diagnostic, or therapeutic exposures. Individual diagnostic radiation procedures (fetal dosage <50 mGy), are not associated with any increase in lethality (miscarriage or stillbirth), genetic damage, teratogenicity, growth impairment, mental retardation, or sterility. More recent modeling has suggested that a 10 mGy fetal dose is associated with an excess risk of childhood cancer risk as low as 1 in 4545, well below historical estimates.When the mother's condition necessitates diagnostic radiation it is necessary to balance the risks of the procedure with the benefits to be gained. As almost all diagnostic imaging involves doses below the 50 mGy threshold, clinically indicated investigations should not be withheld because of concerns regarding fetal radiation exposure. Even radiotherapy directed away from the abdomen or pelvis may be considered during pregnancy, if the benefits outweigh the risks and no suitable alternative is available.     

Comparison of several packings for CO2 chemical absorption in a packed column

CO₂ capture and storage has gained widespread attention as an option for reducing greenhouse gas emissions. Chemical absorption and stripping of CO₂ with hot potassium carbonate (K₂CO₃) solutions has been used in the past, however potassium carbonate solutions have a low CO₂ absorption efficiency. Various techniques can be used to improve the absorption efficiency of this system with one option being the addition of promoters to the solvent and another option being an improvement in the mass transfer efficiency of the equipment. This study has focused on improving the efficiency of the packed column by replacing traditional packings with newer types of packing which have been shown to have enhanced mass transfer performance. Three different packings (Super Mini Rings (SMRs), Pall Rings and Mellapak) have been studied under atmospheric conditions in a laboratory scale column for CO₂ absorption using a 30 wt% K₂CO₃ solution. It was found that SMR packing resulted in a mass transfer coefficient approximately 20% and 30% higher than that of Mellapak and Pall Rings, respectively. Therefore, the height of packed column with SMR packing would be substantially lower than with Pall Rings or Mellapak. Meanwhile, the pressure drop using SMR was comparable to other packings while the gas flooding velocity was higher when the liquid load was above 25 kg m⁻² s⁻¹. Correlations for predicting flooding gas velocities and pressure drop were fitted to the experimental data, allowing the relevant parameters to be estimated for use in later design.     

Veterinary antimicrobials in feedlot manure: dissipation during composting and effects on composting processes

Composting of manure may lead to the degradation of veterinary antimicrobials, but it is largely unknown if the presence of antimicrobials affects the composting process. Open-air windrow composting of manure from beef cattle (Bos taurus) administered chlortetracycline, sulfamethazine, and tylosin was investigated in a 2-yr study. At windrow construction, chlortetracycline had extensively isomerized to iso-chlortetracycline. Sulfamethazine, tylosin, and iso-chlortetracycline dissipated by first-order kinetics, whereas the dissipation of enol/keto-chlortetracycline was better described by exponential equations. At the end of the composting period, proportions of antimicrobials remaining were as follows: iso-chlortetracycline (< 1%), chlortetracycline (1 to 4.5%), tylosin (6.3%), and sulfamethazine (6.8% [2005], 41% [2006]). Times for 50% dissipation (DT50) decreased in the order: tylosin (20.3 to 43.5 d) > iso-chlortetracycline (13.5 to 26.5 d) > enol/keto-chlortetracycline (5.5 to 9.8 d). The DT50 values for sulfamethazine varied from 26.8 d in 2005 to 237 d in 2006. Treatments with chlortetracycline showed significantly reduced temperature rises (10.1 to 11.0 degrees C) between Days 21 to 28 in 2006 compared with rises of 26.6 to 31.0 degrees C for control and tylosin treatments, suggesting an inhibition of microbial activity. During composting in 2005, manure from cattle administered chlortetracycline at 44 mg kg(-1) of feed lost significantly less dry matter, carbon, and nitrogen than manure from cattle fed 11 mg chlortetracycline kg(-1) of feed, implying that the higher level of chlortetracycline inhibited microbial decomposition of organic matter. The study shows that while composting leads to dissipation of antimicrobials, the microbially driven composting process may be inhibited by their presence.     

Phosphorus adsorption and desorption potential of stream sediments and field soils in agricultural watersheds

Phosphorus release from stream sediments into water could increase P loads leaving agricultural watersheds and contribute to lag-time between implementation of best management practices and improvement in water quality. Improved understanding of P release from stream sediments can assist in setting water quality goals and designing stream monitoring programs. The objective of this study was to estimate the relative potential of sediments and soils to release P to stream water in two agricultural watersheds. Stream sediments were collected from banks, pools, riffles, and depositional features. Soils were sampled from wheat, row crop, pasture, and manure-amended fields. Sediments and soils were analyzed for equilibrium P concentration at zero net P sorption (EPC0), maximum P adsorption capacity (P(max)), anion exchange extractable P (P(lab)), and degree of P saturation. Dissolved reactive P (DRP) of stream water was monitored. Stream sediment EPC0 was similar to or less than EPC0 from field soils; however, P(lab) of stream sediments was three times less than field soils. Sediments were sandy and had low P(max) due to low oxalate-extractable Fe and Al, which could be explained by stream geomorphology. Manure-amended fields had the highest EPC0 and P(lab) due to continued inputs of manure-based P; however, conventionally fertilized fields also represented an important P source due to their vast extent. Stream water DRP was similar to EPC0 of sediments during base flow and similar to EPC0 of field soils during storm flow. These results indicate that sediments in these streams are a relatively minor P source.     

Uptake,transformation, and elimination kinetics of paralytic shellfish toxins in white seabream (<Emphasis Type="Italic">Diplodus sargus</Emphasis>)

Marine toxins generated by harmful algal blooms can be transferred through the marine food web and ultimately cause massive deaths of piscivorous predators. However, very few studies have explored the processes of accumulation and biotransformation of paralytic shellfish toxins (PSTs) within fishes. White seabream (Diplodus sargus) were orally challenged with contaminated cockles (Cerastoderma edule) containing N-sulfocarbamoyl and decarbamoyl toxins and non-contaminated cockles afterwards. Specific PSTs that occurred in low abundance in cockles (B1 7.6% and dcSTX 1.6% molar fraction) were the only toxins detected in fish viscera possibly resulting from selective elimination and transformation of the various PSTs. Concentration of toxins progressively increased in fish viscera throughout the uptake period. Toxins were then rapidly depurated (B1 0.905 day⁻¹, dcSTX 0.467 day⁻¹) when diet was changed to non-toxic cockles. Results indicate conversion of a precursor toxin into B1 which in turn might be converted into dcSTX at a lower extent. Low accumulation efficiency of 1.7 and 5.0% was calculated to B1 and dcSTX, respectively. This study contributes to a better understanding of dynamics of PSTs in fish and the fate of these compounds in the marine food web.