Mutualism, Parasitism, and Evolutionary Adaptation

Our investigations concern the role of symbiosis as an enabling mechanism in evolutionary adaptation. Previous work has illustrated how the formation of mutualist groups can guide genetic variation so as to enable the evolution of ultimately independent organisms that would otherwise be unobtainable. The new experiments reported here show that this effect applies not just in genetically related organisms but may also occur from symbiosis between distinct species. In addition, a new detail is revealed: when the symbiotic group members are drawn from two separate species only one of these species achieves eventual independence and the other remains parasitic. It is nonetheless the case that this second species, formerly mutualistic, was critical in enabling the independence of the first. We offer a biological example that is suggestive of the effect and discuss the implications for evolving complex organisms, natural and artificial

Benthic response to sedimentation events during autumn to spring at a shallow water station in the Western Kiel Bight, II. Analysis of benthic bacterial populations

Seasonal variations in bacterial populations (total number, biomass, biomass-spectrum, number of dividing cells) as well as in concentrations and decomposition rates of particulate organic material were followed in a sandy mud sediment of the Western Kiel Bight (Baltic Sea; FRG). The strong seasonal variations observed could be traced back to the effect of certain ecological situations and events in the sediment from which the input of the phytoplankton blooms in autumn and spring, respectively, the accumulation of organic material during winter, and the spring development of the benthic fauna turned out to be the most important. Bacterial carbon net production following the breakdown of the phytoplankton blooms ranged between 9 μg (autumn) and 16 μg (spring) per g of dry weight sediment per day. The consequences of shifts in the size composition of the bacterial populations as well as the importance of the measurement of enzymatic decomposition rates of particulate organic material in sediments are demonstrated and discussed in relation to the events mentioned abov

Saving incentives, old-age provision and displacement effects: evidence from the recent German pension reform

In response to population aging, pay-as-you-go pensions are being reduced in almost all developed countries. In many countries, governments aim to fill the resulting gap with subsidized private pensions. This paper exploits the recent German pension reform to shed new light on the uptake of voluntary, but heavily subsidized private pension schemes. Specifically, we investigate how the uptake of the recently introduced "Riester pensions” depends on state-provided saving incentives, and how well the targeting to families and low-income households works in practice. We show that, after a slow start, private pension plans took off very quickly. While saving incentives were effective in reaching parents, they were less successful in attracting low-income earners, although Riester pensions exhibit a more equal pattern by income than occupational pensions and unsubsidized private pension plans. We also provide circumstantial evidence on displacement effects between saving for old-age provision and other purposes. Households who plan to purchase housing are less likely to have a Riester pension. The same holds for households who attach high importance to a bequest motive. Occupational pensions and other forms of private pensions, however, act as complements rather than as substitute

Relationship between bank vole abundance, seroprevalence and human hantavirus infections

Reil, D., Imholt, C., Schmidt, S., Rosenfeld, U.M., Ulrich, R.G., Eccard, J.A., Jacob, J

ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak National Observatory will deliver light to 5,000 individually targeted fiber-fed robotic positioners. The fibers in turn feed ten broadband multi-object spectrographs. We describe the ProtoDESI experiment, that was installed and commissioned on the 4-m Mayall telescope from August 14 to September 30, 2016. ProtoDESI was an on-sky technology demonstration with the goal to reduce technical risks associated with aligning optical fibers with targets using robotic fiber positioners and maintaining the stability required to operate DESI. The ProtoDESI prime focus instrument, consisting of three fiber positioners, illuminated fiducials, and a guide camera, was installed behind the existing Mosaic corrector on the Mayall telescope. A Fiber View Camera was mounted in the Cassegrain cage of the telescope and provided feedback metrology for positioning the fibers. ProtoDESI also provided a platform for early integration of hardware with the DESI Instrument Control System that controls the subsystems, provides communication with the Telescope Control System, and collects instrument telemetry data. Lacking a spectrograph, ProtoDESI monitored the output of the fibers using a Fiber Photometry Camera mounted on the prime focus instrument. ProtoDESI was successful in acquiring targets with the robotically positioned fibers and demonstrated that the DESI guiding requirements can be met.Comment: Accepted versio

Perceptions and experiences on language anxiety on EEGAFI senior high school students’ English speaking classes: SY 2022-2023

English language is one of the most challenging languages to learn, and students often struggle with it, especially in English-speaking Classes. Additionally, English is widely used throughout the world, which has put second language learners on a difficult path to acquiring excellent communication skills (Lababidi, 2015). In fact, not all students can easily achieve their goals of learning English and follow the language learning process well. In this study, researchers aim to investigate and determine the perceptions and experiences on Language Anxiety of EEGAFI Senior High School Students in English speaking classes. The design selected for this study was quantitative research in natures using interviews. Furthermore, the data has been collected from (n=115) respondents of EEGAFI Senior High School Students. Researchers used simple random sampling method in collecting participants. In this study, it was found out that these five factors (i.e., lack of confidence, poor quality teaching, fear of making mistakes, fear of evaluation, and communication apprehension) are causes of Language Anxiety. In addition, the researchers found that students would feel less anxious when they have lack of confidence and positive thinking, since students selected these as their preferred easing techniques in reducing Language anxiety (see bar graph 1.0). However, students also send some tips on how to reduce language anxiety (see table 1.0)

Observations of the Askaryan Effect in Ice

We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations

Observations of Microwave Continuum Emission from Air Shower Plasmas

We investigate a possible new technique for microwave measurements of ultra-high energy cosmic ray (UHECR) extensive air showers which relies on detection of expected continuum radiation in the microwave range, caused by free-electron collisions with neutrals in the tenuous plasma left after the passage of the shower. We performed an initial experiment at the AWA (Argonne Wakefield Accelerator) laboratory in 2003 and measured broadband microwave emission from air ionized via high energy electrons and photons. A follow-up experiment at SLAC (Stanford Linear Accelerator Center) in summer of 2004 confirmed the major features of the previous AWA observations with better precision and made additional measurements relevant to the calorimetric capabilities of the method. Prompted by these results we built a prototype detector using satellite television technology, and have made measurements indicating possible detection of cosmic ray extensive air showers. The method, if confirmed by experiments now in progress, could provide a high-duty cycle complement to current nitrogen fluorescence observations of UHECR, which are limited to dark, clear nights. By contrast, decimeter microwave observations can be made both night and day, in clear or cloudy weather, or even in the presence of moderate precipitation.Comment: 15 pages, 13 figure

Observations of the Askaryan Effect in Ice

We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations.Comment: 4 pages, 5 figures, minor correction