Process-based simulation library SALMO-OO for lake ecosystems. Part 2: Multi-objective parameter optimization by evolutionary algorithms

SALMO-OO represents an object-oriented simulation library for lake ecosystems that allows to determine generic model structures for certain lake categories. It is based on complex ordinary differential equations that can be assembled by alternative process equations for algal growth and grazing as well as zooplankton growth and mortality. It requires 128 constant parameters that are causally related to the metabolic, chemical and transport processes in lakes either estimated from laboratory and field experiments or adopted from the literature.An evolutionary algorithm (EA) was integrated into SALMO-OO in order to facilitate multi-objective optimization for selected parameters and to substitute them by optimum temperature and phosphate functions. The parameters were related to photosynthesis, respiration and grazing of the three algal groups diatoms, green algae and blue-green algae. The EA determined specific temperature and phosphate functions for same parameters for 3 lake categories that were validated by ecological data of six lakes from Germany and South Africa.The results of this study have demonstrated that: (1) the hybridization of ordinary differential equations by EA provide a sophisticated approach to fine-tune crucial parameters of complex ecological models, and (2) the multi-objective parameter optimization of SALMO-OO by EA has significantly improved the accuracy of simulation results for three different lake categories.     

Pione lampa,a bioeroding sponge in a worm reef

A bioeroding sponge was found in a sabellariid worm reef in Florida, USA. The sponge was investigated with standard techniques for species identification (tissue digestion, microscopy techniques, examination of spicules) and was identified as the clionid Pione lampa (De Laubenfels, 1950). This species is extremely similar to Pione vastifica (Hancock, 1849). Morphological and ecological similarities and possible dissimilarities are discussed. Arguments for conspecifity were found to be weaker than evidence of P. lampa and P. vastifica being separate species. The sampled sponge contained asexual reproductive elements: superficial buds and internal gemmules. Buds were very delicate, consisting mainly of a radially-oriented mesh of collageneous threads. They further comprised abundant granular material and acanthose microrhabds. Numerous choanosomal gemmules were found in the sponge body attached to erosion chamber walls. They were subspherical to lenticular and had an aspicular, unstructured, smooth and rigid coat. It enclosed dense cell material and various spicule types. Whereas buds are interpreted to function as dispersal elements, gemmules will primarily ensure survival under adverse conditions such as smothering, exposure to air and high temperatures. Gemmules from this site might occasionally be freed and scattered, since the Florida reef can suffer heavy damage during periods of increased wave activity such as that created during hurricane season. Bioerosion activity of the sponge increases the chance to free gemmules, as the sponge not only etches into calcareous particles cemented into the matrix produced by the worms, but also into the matrix itself. This ability enables the sponge to utilise the reef as substrate. Within the Clionidae, Cliona annulifera and three species of the genus Pione are the only species known to produce typical gemmules. Possible reasons are: (1) reproduction of bioeroding sponges is understudied and asexual bodies may have been overlooked in other species, and (2) clionid gemmules are an adaptation to survive life in risky environments. Sponges of the genus Pioneare comparatively successful in environments in which they are close to their physical limits or in potentially unstable or mobile substrates.     

Reference values of selenium in plasma in population from Barcelona. Comparison with several pathologies

Plasma selenium reference values from healthy donors in the metropolitan area of Barcelona are determined. A random sample from 156 healthy adults (control group) is analysed by using electrothermal atomic absorption spectrometry with Zeeman effect background correction.

The relationship between several pathologies and Se content is also evaluated. Se content from 64 samples from subjects with chronic renal failure and 54 from subjects suffering from several malignancies are determined and the results are compared to the reference values. Moreover, Se contents are determined and compared in two groups of children, healthy (19 samples) and children of mothers infected with HIV-1 (16 samples).

In the control group, Se plasma concentration ranges between 50 and 145 μg · L⁻¹ (82.2 ± 17.5 μg · L⁻¹). Significantly lower values are found in the two pathologies studied (malignancy and chronic renal failure), compared to the control group. However, no significant differences in Se content are found between the two groups studied regarding malignancy and chronic renal failure.

In children of mothers infected with HIV-1, Se status is significantly lower than that of healthy children.     

The spread of agriculture in northern Iberia: new archaeobotanical data from El Mirón cave (Cantabria) and the open-air site of Los Cascajos (Navarra)

This paper presents archaeobotanical results from the Neolithic levels (5,300–4,000 b.c.) of two recently excavated sites in northern Iberia: El Mirón cave (Cantabria) and the open-air site of Los Cascajos (Navarra). A cereal grain from El Mirón is currently the earliest domesticated plant remain from this region. Despite the large number of samples examined, plant remains are few. They include basically cereals (Triticum monococcum, T. dicoccum, T. aestivum/durum/turgidum and Hordeum vulgare) and some nuts and fruits (Corylus avellana, Quercus sp., Vitis sp., etc.). The presence of free-threshing wheats at El Mirón opens up an interesting subject for debate, as until now naked wheats have been absent from the early Neolithic archaeobotanical record of the coastal Cantabrian region. Hulled wheat chaff is the main plant component from Los Cascajos, south of the Cantabrian Cordillera in Navarra, indicating waste from processing activities. The association of barley almost exclusively with both a burial and a ritual vase in Los Cascajos could be related specific rituals or ceremonies.     

Characterization of histone inheritance patterns in the Drosophila female germline

Stem cells have the unique ability to undergo asymmetric division which produces two daughter cells that are genetically identical, but commit to different cell fates. The loss of this balanced asymmetric outcome can lead to many diseases, including cancer and tissue dystrophy. Understanding this tightly regulated process is crucial in developing methods to treat these abnormalities. Here, we report that during a Drosophila female germline stem cell asymmetric division, the two daughter cells differentially inherit histones at key genes related to either maintaining the stem cell state or promoting differentiation, but not at constitutively active or silenced genes. We combine histone labeling with DNA Oligopaints to distinguish old versus new histones and visualize their inheritance patterns at a single‐gene resolution in asymmetrically dividing cells in vivo. This strategy can be applied to other biological systems involving cell fate change during development or tissue homeostasis in multicellular organisms.     

Population-based resequencing reveals that the flowering time adaptation of cultivated barley originated east of the Fertile Crescent

Gene resequencing and association analysis present new opportunities to study the evolution of adaptive traits in crop plants. Here we apply these tools to an extensive set of barley accessions to identify a component of the molecular basis of the flowering time adaptation, a trait critical to plant survival. Using an association-based study to relate variation in flowering time to sequence-based polymorphisms in the Ppd-H1 gene, we identify a causative polymorphism (SNP48) that accounts for the observed variation in barley flowering time. This polymorphism also shows latitude-dependent geographical distribution, consistent with the expected clinal variation in phenotype with the nonresponsive form predominating in the north. Networks, genealogies, and phylogenetic trees drawn for the Ppd-H1 haplotypes reveal population structure both in wild barley and in domesticated barley landraces. The spatial distribution of these population groups indicates that phylogeographical analysis of European landraces can provide information relevant to the Neolithic spread of barley cultivation and also has implications for the origins of domesticated barley, including those with the nonresponsive ppd-H1 phenotype. Haplotypes containing the nonresponsive version of SNP48 are present in wild barley accessions, indicating that the nonresponsive phenotype of European landraces originated in wild barley. The wild accessions whose nonresponsive haplotypes are most closely similar to those of landraces are found in Iran, within a region suggested as an area for domestication of barley east of the Fertile Crescent but which has previously been thought to have contributed relatively little to the diversity of European cultivars.     

Effect of a brief video intervention on incident infection among patients attending sexually transmitted disease clinics

Background

Sexually transmitted disease (STD) prevention remains a public health priority. Simple, practical interventions to reduce STD incidence that can be easily and inexpensively administered in high-volume clinical settings are needed. We evaluated whether a brief video, which contained STD prevention messages targeted to all patients in the waiting room, reduced acquisition of new infections after that clinic visit.

Methods and Findings

In a controlled trial among patients attending three publicly funded STD clinics (one in each of three US cities) from December 2003 to August 2005, all patients (n = 38,635) were systematically assigned to either a theory-based 23-min video depicting couples overcoming barriers to safer sexual behaviors, or the standard waiting room environment. Condition assignment alternated every 4 wk and was determined by which condition (intervention or control) was in place in the clinic waiting room during the patient''s first visit within the study period. An intent-to-treat analysis was used to compare STD incidence between intervention and control patients. The primary endpoint was time to diagnosis of incident laboratory-confirmed infections (gonorrhea, chlamydia, trichomoniasis, syphilis, and HIV), as identified through review of medical records and county STD surveillance registries. During 14.8 mo (average) of follow-up, 2,042 patients (5.3%) were diagnosed with incident STD (4.9%, intervention condition; 5.7%, control condition). In survival analysis, patients assigned to the intervention condition had significantly fewer STDs compared with the control condition (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.84 to 0.99).

Conclusions

Showing a brief video in STD clinic waiting rooms reduced new infections nearly 10% overall in three clinics. This simple, low-intensity intervention may be appropriate for adoption by clinics that serve similar patient populations.Trial registration: http://www.ClinicalTrials.gov (#{"type":"clinical-trial","attrs":{"text":"NCT00137670","term_id":"NCT00137670"}}NCT00137670).