Contributions to the flora and vegetation of Kagbeni (Mustan District, Central Nepal)

Kagbeni and its irrigated oasis are surrounded by subdesert dwarf scrubland. In the present study, a list of 78 species of vascular plants is presented for Kagbeni and its immediate surroundings, supplemented with data on the distribution of the species within the entire Mustan District. The data are arrived from own investigations and the geobotanical literature. A phytogeographical analysis shows the prevalence of western over eastern elements. Species with a wide distribution in Eurasia, which constitute one third of the total flora of Kagbeni, are of great importance as weeds on arable fields and in ruderal places within the irrigated oasis. Their occurrence is closely related to human activity. Presumably, most of these weeds have reached the area under study in connection with agriculture a long time ago. Weeds from the New World, although recorded in other villages of Mustan District, have not been found in Kagbeni. The weed vegetation of Kagbeni is documented by nine vegetation releves, and is compared to releves from Jomsom and Mzrpha. A floristic gradient from south to north that has been detected by earlier investigations throughout the whole district can be reproduced at the local scale. With regard to the weed flora, the effects of different crops are minimal, compared to effects of altitude and other factors related to altitude

Farm level environmental indicators; are they useful? An overview of Green Accounting Systems for European farms

Green accounts or Input-Output Accounting systems (IOA) have been developed in countries with intensive agricultural production to facilitate voluntary improvements in farm environmental performance. There is a need for an overview of indicators used and a review of results and experiences reported. Ten IOA systems covering the topics of the farm's use of nutrients, pesticides and energy were selected from a survey of 55 systems and compared in this paper. The approaches and indicators used vary from systems based on Good Agricultural Practices (GAP) to accounts based systems that use physical input-output units. Many IOA systems use farm gate nutrient balances, pesticide use per ha and energy use per kg product. These indicators are easy to calculate but the resulting value needs separate interpretation for the farmer. Other systems include modelled emissions and rate the yearly farm results using closed scales, which allows for easy interpretation but builds on implicit normative assumptions of best practices. Participating farmers were most often reported to be motivated for the use of IOA but empirical evidence of improved environmental farm performance was scarce. IOA systems should be linked with production planning tools used by the advisory services. Farmers and advisors needs better reference values to evaluate the indicator levels (environmental performance) on the individual farm possibly based on analysis of a larger number of farms. The statistical properties of IOA indicators need to be researched regarding: (1) The relation between changed management practice and changes in indicator values on a given farm over a period of time. (2) The relative importance of systematic vs. coincidental differences in environmental performance of a set of farms. It is concluded that IOA systems could become effective tools for agri-environmental improvement of European farms given further development and standardisation

Coupling a single electron on superfluid helium to a superconducting resonator.

Electrons on helium form a unique two-dimensional system on the interface of liquid helium and vacuum. A small number of trapped electrons on helium exhibits strong interactions in the absence of disorder, and can be used as a qubit. Trapped electrons typically have orbital frequencies in the microwave regime and can therefore be integrated with circuit quantum electrodynamics (cQED), which studies light-matter interactions using microwave photons. Here, we experimentally realize a cQED platform with the orbitals of single electrons on helium. We deterministically trap one to four electrons in a dot integrated with a microwave resonator, allowing us to study the electrons' response to microwaves. Furthermore, we find a single-electron-photon coupling strength of [Formula: see text] MHz, greatly exceeding the resonator linewidth [Formula: see text] MHz. These results pave the way towards microwave studies of Wigner molecules and coherent control of the orbital and spin state of a single electron on helium

A convergent Born series for solving the inhomogeneous Helmholtz equation in arbitrarily large media

We present a fast method for numerically solving the inhomogeneous Helmholtz equation. Our iterative method is based on the Born series, which we modified to achieve convergence for scattering media of arbitrary size and scattering strength. Compared to pseudospectral time-domain simulations, our modified Born approach is two orders of magnitude faster and nine orders of magnitude more accurate in benchmark tests in 1-dimensional and 2-dimensional systems

Rapid Communication with a “P300” Matrix Speller Using Electrocorticographic Signals (ECoG)

A brain–computer interface (BCI) can provide a non-muscular communication channel to severely disabled people. One particular realization of a BCI is the P300 matrix speller that was originally described by Farwell and Donchin (1988). This speller uses event-related potentials (ERPs) that include the P300 ERP. All previous online studies of the P300 matrix speller used scalp-recorded electroencephalography (EEG) and were limited in their communication performance to only a few characters per minute. In our study, we investigated the feasibility of using electrocorticographic (ECoG) signals for online operation of the matrix speller, and determined associated spelling rates. We used the matrix speller that is implemented in the BCI2000 system. This speller used ECoG signals that were recorded from frontal, parietal, and occipital areas in one subject. This subject spelled a total of 444 characters in online experiments. The results showed that the subject sustained a rate of 17 characters/min (i.e., 69 bits/min), and achieved a peak rate of 22 characters/min (i.e., 113 bits/min). Detailed analysis of the results suggests that ERPs over visual areas (i.e., visual evoked potentials) contribute significantly to the performance of the matrix speller BCI system. Our results also point to potential reasons for the apparent advantages in spelling performance of ECoG compared to EEG. Thus, with additional verification in more subjects, these results may further extend the communication options for people with serious neuromuscular disabilities

Biological bibliography online : BioLIS

Die Datenbank BioLIS wird durch die Universitätsbibliothek Johann Christian Senckenberg (Frankfurt/M.) kostenfrei online zur Verfügung gestellt. Sie weist deutsche biologische Zeitschriftenliteratur aus dem Zeit¬raum 1970 bis 1996 nach – damit ist BioLIS eine wesentliche Ergänzung zu der Datenbank „Biological Abstracts“. Die bibliografischen Angaben zu den nachgewiesenen Aufsätzen werden durch umfassende Schlagwörter und Namen behandelter Organismen ergänzt, so dass Spezialrecherchen insbesondere nach Literatur über bestimmte Organismen möglich sind.The database BioLIS is provided online by the University Library Johann Christian Senckenberg (Frankfurt/Main, Germany). Originally conceived as a supplement to „Biological Abstracts“, BioLIS comprises metadata on german biological journal papers from the period 1970 to 1996

The transmission of H5 and H7 low pathogenic avian influenza viruses

Avian influenza viruses (AIVs) are a diverse group of viruses that are a major global threat to the poultry industry. To date, 16 HA and 9 NA subtypes of avian influenza have been observed in birds. Most of these subtypes cause no or only mild disease in poultry and are therefore classified as low pathogenic avian influenza viruses (LPAIVs). However, as a result of mutations, LPAIVs belonging to the H5 or H7 subtypes (LPNAIVs) may evolve into a highly pathogenic avian influenza virus (HPAIV) when they are circulating in poultry. Since these HPAIVs cause severe sickness and mortality in poultry and are able to spread rapidly, such an outbreak can wreak havoc among poultry holdings in a large region. In order to prevent the emergence of a HPAIV, it is important that LPNAI outbreaks in poultry are detected as soon as possible and that control measures can be applied before the virus has the opportunity to become widespread. In order to achieve this, active surveillance programs directed towards an early detection of LPNAIV in poultry holdings are established. It is believed that focusing the current active surveillance programs on those sectors of the poultry industry that are more susceptible to a LPNAIV infection, would lead to an earlier detection of LPNAIV. To this end, it is necessary that those factors that determine whether a poultry holding is at increased risk for infection with LPNAIV are identified. In this thesis, transmission experiments were designed to identify and study some putative risk factors for LPNAIV infection in poultry holdings. In a first series of transmission experiments (Chapter 3), the transmission of three LPNAIVs between SPF chickens was studied. A H5N2 LPAIV, which had been isolated from chickens and a H7N1 LPAIV which had also been isolated from chickens, were found to be highly infectious and transmissible to SPF chickens. In contrary, a H5N3 LPAIV that had been isolated from wild ducks proved to be low infectious to SPF chickens and was not transmitted between them. It was additionally examined whether keeping chickens in cage or barn housing could influence the transmission of LPNAIV. To achieve this, differences in virus transmission were studied between SPF chickens housed on a grid (to simulate housing in enriched cages) and SPF chickens housed on a floor covered with wood shavings (to simulate floor-based housing). The obtained results suggest that the transmission of LPNAIVs may be slightly enhanced by the accumulation of fecal matter as it occurs in floor-based housing systems. However, no large impact was observed. In order to decide whether this factor should be regarded as a risk factor and be included in the active LPNAI surveillance programs, further investigation should be conducted. This could be realized by conducting additional transmission experiments or by conducting an epidemiological study looking for a relationship between LPNAI outbreaks and the type of housing system. A second set of transmission experiments (Chapter 4) was dedicated to the investigation of the transmission of LPNAIVs between ducks and chickens. In these experiments, the transmission of the duck originated H5N3 LPAIV that was also used in chapter 3 was investigated between pekin ducks and SPF chickens. Despite this virus was previously found to be low infectious to SPF chickens, it was found to be efficiently transmitted from pekin ducks to SPF chickens, suggesting that this virus can be efficiently introduced in chicken farms if contact with wild waterfowl is possible. Additionally, from experiments with a special setting, it was suggested that drinking water that is fecally contaminated by visiting waterfowl may be one of the most important fomites by which LPNAIVs are introduced to poultry holdings. From these results, it can be suggested that the risk of a wild bird originated LPNAIV becoming established in poultry is only realistic if the virus itself has a high infectious potential to poultry. Indeed, our results suggest that, despite the fact that they can be relatively easily introduced, a LPNAIV with a low infectious potential to chickens has a significant risk of dying out spontaneously when it is introduced in an all-chicken population. On the other hand, in mixed poultry farms where contact between domestic waterfowl and gallinaceous poultry is possible, these low infectious LPNAIVs may be of a bigger problem; It is possible that such a LPNAIV can circulate among the holding’s waterfowl and can then be repeatedly passed on to the chickens. This would theoretically enable the virus to adapt to chickens, which means that these mixed poultry holdings can act as a bridge for the virus to cross the species barrier from its natural host to gallinaceous poultry. In a third study (Chapter 5); it was evaluated if transmission of the H5N2 and H7N1 LPAIVs used in chapter 3 still occurs when a more natural infection pressure is used. Indeed, it is often assumed that the inoculation of animals, as carried out in standard transmission experiments, may lead to a higher infectivity and thus to an artificially enhanced transmission. Extended transmission experiments in which susceptible SPF chickens were exposed to naturally infected SPF chickens were carried out. For the H5N2 LPAIV, it was observed that the reproduction ratio was similar to the one obtained in chapter 3. This suggests a similar infectivity for naturally infected SPF chickens as for inoculated SPF chickens, at least for this virus. Unfortunately, for the H7N1 LPAIV, no conclusions could be drawn; naturally infected SPF chickens could not be obtained, most likely due to problems in the design of the experiment. In a final study (Chapter 6), the multispecies NP-ELISA kit that was used throughout the thesis for the determination of infection was compared with other commercially available multispecies NP-ELISA kits. A selection of chicken and duck sera from the transmission experiments (chapter 3 and 4) were analyzed and results were compared. As these kits are also widely used in the active surveillance of LPNAIV in wild waterfowl, some additional field sera from wild geese, swans and ducks were included. The results suggest that the currently available commercial multispecies NP-ELISA kits perform equivalent for the analysis of chicken sera, and that they are most probably more sensitive than the current standard, the HI test. For wild bird sera however, a high degree of inconsistency between the different kits was observed. This indicates that, whilst the currently available commercial multispecies NP-ELISA kits are reliable for the active LPNAI surveillance in chickens, they can give unreliable results for wild bird sera. Hence, either these kits need to be better calibrated for the use in these species, or more reliable alternatives need to be investigated

Bibliographic records of botanical literature on Hesse : present state and prospects

Die Möglichkeiten zum Recherchieren von botanischer Literatur über Hessen in sieben Online-Datenbanken werden vergleichend betrachtet. Unter anderem werden Testrecherchen zu Beiträgen in den Zeitschriften Hessische Floristische Briefe und Botanik und Naturschutz in Hessen ausgewertet. Es stellt sich heraus, dass im Feld der getesteten Datenbanken die Hessische Bibliographie sowie Biological Abstracts jeweils eine besondere Stellung einnehmen; mehrere weitere, überwiegend lizenzfrei nutzbare Datenbanken liefern ebenfalls substanzielle Beiträge. Die von der Universitätsbibliothek Johann Christian Senckenberg in Frankfurt am Main aufgebaute Virtuelle Fachbibliothek Biologie (vifabio) erleichtert den Zugang zu einigen wesentlichen Ressourcen; unter anderem können Hessische Bibliographie und Biological Abstracts sowie weitere Datenbanken in vifabio mit einer einzigen Suchanfrage parallel durchsucht werden.The possibilities for researching botanical literature on Hesse were compared in seven online databases. Results of test searches for papers in the journals Hessische Floristische Briefe und Botanik und Naturschutz in Hessen, amongst others, were evaluated. It turns out that, amongst the field of tested databases, the Hessian Bibliography and Biological Abstracts place well. Several other, predominantly license-free usable databases offer similar substantial contributions. The Virtual Library of Biology (vifabio), developed by the University Library Johann Christian Senckenberg in Frankfurt am Main, enables access to several fundamental resources; in vifabio, the Hessian Bibliography and Biological Abstracts (for German academic institutions), as well as other databases, can be searched simultaneously with a single query