Impact of prey field variability on early cod larval survival: a sensitivity study of a Baltic cod Individual-based Model

Existing coupled biophysical models for Baltic larval cod drift, growth and survival use idealised constructed mean prey fields of nauplius distributions. These simulations revealed the best feeding conditions for Baltic cod larvae longer than 6 mm. For shorter, first feeding larvae (between 4.5 and 6 mm) pronounced differences in growth and survival were observed, which depend on food availability and to a lesser degree on ambient temperature. We performed runs with an Individual-based Model (IBM) for Baltic cod larvae in order to demonstrate how natural variability in prey abundance influences the survival success of first feeding larvae. In the Baltic, this larval stage lives mainly between 20 and 40 m depth and feeds exclusively on the nauplii of different calanoid copepods (Acartia spp., Pseudocalanus acuspes, Temora longicornis and Centropages hamatus). Prey data obtained from vertically stratified samples in the Bornholm Basin (Baltic Sea) in 2001 and 2002 indicate a strong variability at spatial and temporal scales. We calculated larval survival and growth in relation to natural variation of prey fields, i.e. species-specific nauplius abundance. The results of the model runs yielded larval survival rates from 60 to 100% if the mean size of nauplii species was taken and lower survival if prey consisted of early nauplius stages only

Ferroelectric control of the spin texture in germanium telluride

The electrical manipulation of spins in semiconductors, without magnetic fields or auxiliary ferromagnetic materials, represents the holy grail for spintronics. The use of Rashba effect is very attractive because the k-dependent spin-splitting is originated by an electric field. So far only tiny effects in two-dimensional electron gases (2DEG) have been exploited. Recently, GeTe has been predicted to have bulk bands with giant Rashba-like splitting, originated by the inversion symmetry breaking due to ferroelectric polarization. In this work, we show that GeTe(111) surfaces with inwards or outwards ferroelectric polarizations display opposite sense of circulation of spin in bulk Rashba bands, as seen by spin and angular resolved photoemission experiments. Our results represent the first experimental demonstration of ferroelectric control of the spin texture in a semiconductor, a fundamental milestone towards the exploitation of the non-volatile electrically switchable spin texture of GeTe in spintronic devices.Comment: 18 pages, 4 figure

Brief Note Daphnia Swarms in the Harbor at Put-In-Bay

Author Institution: Franz Theodore Stone Laboratory, The Ohio State Universit

Limnological deterioration forces community and phenotypic changes in Cladocera : Tracking eutrophication of Mallusjärvi, a lake in southern Finland

Peer reviewe

Zooplankton richness, abundance and biomass of two hypertrophic shallow lakes with different salinity

The zooplankton of lakes is controlled by biological and physico-chemical parameters. Among the former, predation by fish can determine the replacement of large-sized species by small-sized ones and among the latter, salinity exerts negative effects on richness and abundance. Since it has been suggested that saline lakes without fishes have higher zooplankton biomass than low salinity ones, the aim of this study was to determine the richness, abundance and biomass of zooplankton in two lakes with different salinity and test the hypothesis that in the presence of zooplanktivorous fishes and at equal concentrations of nutrients and chlorophyll a, saline lakes have higher biomass than those with low salinity. The study was conducted in two shallow lakes of the Province of La Pampa (central Argentina): a subsaline lake and a hyposaline lake, which shared high concentrations of chlorophyll a and total phosphorus, reduced transparency and presence of planktivorous fish. Zooplankton richness was different and higher in the subsaline lake, whereas abundance and total biomass were similar, even when the taxonomic groups were considered separately. It is suggested that the presence of a halotolerant planktivorous fish controlled the size of zooplankton due to the predation on larger species and prevented the development of higher biomass in the saline lake, which is an important difference from previously recorded situations. This study shows that, regardless of the differences in salinity, the top-down effect in the food chain may have been a factor that equalized the zooplankton biomass by allowing only the development of small species and highlights the possible importance of fish predation in determining chlorophyll a concentrations and water transparency.Fil: Echaniz, Santiago Andrés. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Vignatti, Alicia María. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cabrera, Gabriela Cecilia. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Jose, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Telluride thin films: growth, strain, structure and thermoelectric properties

Utilizing a superlattice structure is an advantage in enhancing the thermoelectric performance. For instance, the Bi2Te3/Sb2Te3 superlattice is famous for its exceptionally high figure of merit. 3D/3D films systems have been studied most intensely and have been successfully applied in industry. However, introduction of 2D materials makes the strain behaviour in hetero-structures elusive. It is well known that the electronic properties of materials can be extremely sensitive to the strain, and doping can easily affect the Seebeck coefficient of materials. However, the strain state and the thermal stability of these multilayers are still not studied in-depth, which may be the possible reasons why different researchers generated such a wide spread in (thermoelectric) data. In this thesis, we use telluride films i.e., Bi2Te3, Sb2Te3, Ge1+xTe, and GeTe, as examples to address the strain evolution in these materials and how the nanostructure and intermixing affect the thermoelectric properties

Impact of Hatha Yoga Sadhana and Natya Yoga Training on Forced Expiratory Volume Among Men and Women

The purpose of the study was to find out the Impact of Hatha Yoga Sadhana and Natya Yoga Training on Forced Expiratory Volume (FEV1) among Men and Women. The findings of the study were exploring the status of Hatha Yoga Sadhana and Natya Yoga Training among Men and Women. The findings of the study will be helpful for further research studies, also helpful for Men and Women. For the study, 60 members of Men and Women selected form Chennai, at Vethathiri Maharishi College of Yoga, between the age group of 20 to 28 years, and they were randomized 15 members in each group. FEV1 was measured by Digital spirometer, pre and post were conducted before and after training. Subjects were divided into three group as such in Group-I acted as Control Group, Group-II acted as Hatha Yoga Sadhana, and Group-III were undergone into Natya Yoga Training. Data were collected and scored and analysed in to’ t’test and ANACOVA. The results revealed that there was significant difference in men and women, as well as there was significant difference when compared in to control group. And also there was significant difference when comparing Hatha Yoga Sadhana and Natya Yoga Training groups

Length-weight regressions for zooplankton biomass calculations – A review and a suggestion for standard equations

Zooplankton biomass can be estimated through the use of equations that convert length of individuals to dry weight. The logarithmic transformation of these power equations follow the form Ln(W) =Ln(α) + β Ln(L) where L is length in mm, W is dry weight in ug, and α and β are species-specific values. Several sets of L-W equations have been developed for use in the Great Lakes region by agencies such as the Environmental Protection Agency (EPA) and Canada’s Department of Fisheries and Oceans (DFO). Since we collaborate with both agencies and require comparability with previously collected data, we reviewed these two sets of equations and the publications that were used to develop them. We offer a third Cornell Standard (CBFS STD) set that resolves many of the discrepancies seen in the other sets.Funded by the Great Lakes Restoration Initiative through the Environmental Protection Agency and the International Joint Commission

A trophic bottleneck?: The ecological role of trout‐perch P ercopsis omiscomaycus in S aginaw B ay, L ake H uron

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97230/1/jai12023.pd