Fiscal Spending Multiplier Calculations based on Input-Output Tables – with an Application to EU Members

Fiscal spending multiplier calculations have been revived in the aftermath of the global financial crisis. Much of the current literature is based on VAR estimation methods and DSGE models. The aim of this paper is not a further deepening of this literature but rather to implement a calculation method of multipliers which is suitable for open economies like EU member states. To this end, Input-Output tables are used as by this means the import intake of domestic demand components can be isolated in order to get an appropriate base for the calculation of the relevant import quotas. The difference of this method is substantial – on average the calculated multipliers are 15% higher than the conventional GDP fiscal spending multiplier for EU members. Multipliers for specific spending categories are comparably high, ranging between 1.4 and 1.8 for many members of the EU. GDP drops due to budget consolidation might therefore be substantial if monetary policy is not able to react in an expansionary manner.fiscal spending multiplier calculation, Input-Output calculus, income-expenditure model, European Union, stimulus, consolidation

Classifiying advanced concepts to assess device requirements for high efficiency solar cells

The efficiency of terrestrial solar energy conversion is fundamentally limited by the Landsberg limit of 93%. Single junction solar cells can, however, reach only about a third of this efficiency, a limitation first formulated by Shockley and Queisser [1]. Many concepts have been proposed to overcome this Shockley-Queisser (SQ) limit for single junction solar cells. In this contribution, we are going to explore the classification of these concepts according to the processes that occur in them and explain how this affects model-building for these devices and the requirements they have to fulfil

T-loop phosphorylation of Arabidopsis CDKA;1 is required for its function and can be partially substituted by an aspartate residue

As in other eukaryotes, progression through the cell cycle in plants is governed by cyclin-dependent kinases. Phosphorylation of a canonical Thr residue in the T-loop of the kinases is required for high enzyme activity in animals and yeast. We show that the Arabidopsis thaliana Cdc21/Cdc28 homolog CDKA; 1 is also phosphorylated in the T-loop and that phosphorylation at the conserved Thr-161 residue is essential for its function. A phospho-mimicry T161D substitution restored the primary defect of cdka; 1 mutants, and although the T161D substitution displayed a dramatically reduced kinase activity with a compromised ability to bind substrates, homozygous mutant plants were recovered. The rescue by the T161D substitution, however, was not complete, and the resulting plants displayed various developmental abnormalities. For instance, even though flowers were formed, these plants were completely sterile as a result of a failure of the meiotic program, indicating that different requirements for CDKA; 1 function are needed during plant development

Analytical expressions for the efficiency limits of radiatively coupled tandem solar cells

The limiting efficiency for series-connected multijunction solar cells is usually calculated from the assumption that the individual junctions are optically isolated. Here, we develop an analytical formalism to predict efficiencies attainable in the presence of luminescent coupling, i.e. if the individual junctions in a series-connected multi-junction stack are coupled optically, so that luminescence from one junction can be absorbed by the lower bandgap junction below. The formalism deals with non-radiative recombination through the definition of the luminescence extraction efficiency. Using our general formalism we find that the limiting efficiency of a tandem cell becomes much less dependent on exact bandgap combination when luminescent coupling is considered and proceed to consider two technologically important examples of current-mismatched tandem solar cells. We find that a series-connected GaAs on silicon tandem cell can be more efficient than the underlying silicon cell alone, if the luminescence extraction efficiency of the GaAs junction is sufficient. An analysis of luminescent coupling in a perovskite on silicon tandem cell shows that the efficiency penalty for a perovskite bandgap below the optimum value can be mitigated if the luminescence extraction efficiency is high. We suggest that material quality and stability might be more important considerations for perovskite on silicon tandems than engineering the bandgap to achieve precise current matching

Overcoming losses with gain in a negative refractive index metamaterial

On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we investigate the possibility of using gain to overcome losses in a negative refractive index fishnet metamaterial. We show that appropriate placing of optically pumped laser dyes (gain) into the metamaterial structure results in a frequency band where the nonbianisotropic metamaterial becomes amplifying. In that region both the real and the imaginary part of the effective refractive index become simultaneously negative and the figure of merit diverges at two distinct frequency points.Comment: 4 pages, 4 figure

School-Based Mental Health Services and Programs: A Review of the Literature

In Chapter 1, a rationale, a statement regarding the focus of my paper, and historical backgrounds of both community-based mental health services and the history surrounding school-based mental health (SBMH) services were provided. In Chapter 2, I review 15 studies dated between 2003 and 2017 addressing the results of school-based mental health programs involving either an in-school parental component or services delivered by clinicians in school settings and the implications SBMH presents for the educational system and its personnel. Studies reviewed are summarized in chronological order and include both quantitative data pertaining to changes in behavioral and academic qualities in children and adolescents deemed “at risk” or diagnosed with mental health disorders, as well as qualitative input related to factors contributing to the success of school-based interventions. In the final chapter, I summarize my findings and provide my conclusions and recommendations for future research

Photoluminescence upconversion at GaAs/InGaP2 interfaces driven by a sequential two-photon absorption mechanism

This paper reports on the results of an investigation into the nature of photoluminescence upconversion at GaAs/InGaP2 interfaces. Using a dual-beam excitation experiment, we demonstrate that the upconversion in our sample proceeds via a sequential two-photon optical absorption mechanism. Measurements of photoluminescence and upconversion photoluminescence revealed evidence of the spatial localization of carriers in the InGaP2 material, arising from partial ordering of the InGaP2. We also observed the excitation of a two-dimensional electron gas at the GaAs/InGaP2 heterojunction that manifests as a high-energy shoulder in the GaAs photoluminescence spectrum. Furthermore, the results of upconversion photoluminescence excitation spectroscopy demonstrate that the photon energy onset of upconversion luminescence coincides with the energy of the two-dimensional electron gas at the GaAs/InGaP2 interface, suggesting that charge accumulation at the interface can play a crucial role in the upconversion process

Coulomb effects on the photoexcited quantum dynamics of electrons in a plasmonic nanosphere

With recent experiments investigating the optical properties of progressively smaller plasmonic particles, quantum effects become increasingly more relevant, requiring a microscopic description. Using the density matrix formalism we analyze the photoexcited few-electron dynamics of a small plasmonic nanosphere. Following the standard derivation of the bulk plasmon we particularly aim at elucidating the role of the Coulomb interaction. Calculating the dielectric susceptibility spectrum in the linear optical response we find discrete resonances resulting from a collective response mediated by the Coulomb interaction between the electrons. In the nonlinear regime, the occupations of the system exhibit oscillations between the interacting eigenstates. Our approach provides an ideal platform to study and explain nonlinear and quantum plasmonics, revealing that the photoexcited dynamics of plasmonic nanospheres has similarities with and combines characteristics of both the well-known two-level Rabi dynamics and the collective many-electron behavior typical of plasmons

Control and Dynamic Competition of Bright and Dark Lasing States in Active Nanoplasmonic Metamaterials

Active nanoplasmonic metamaterials support bright and dark modes that compete for gain. Using a Maxwell-Bloch approach incorporating Langevin noise we study the lasing dynamics in an active nano-fishnet structure. We report that lasing of the bright negative-index mode is possible if the higher-Q dark mode is discriminated by gain, spatially or spectrally. The nonlinear competition during the transient phase is followed by steady-state emission where bright and dark modes can coexist. We analyze the influence of pump intensity and polarization and explore methods for mode control.Comment: 5 pages, 4 figure

Microscopic reversibility demands lower open circuit voltage in multiple exciton generation solar cells

Multiple exciton generation (MEG) increases the short circuit current of solar cells and is, therefore, often cited as a candidate scheme for surpassing the efficiency limit of single junction solar cells. Conventionally, limiting efficiencies for MEG solar cells have been calculated using quasi-equilibrium models that implicitly assume an effective separation of timescales between different processes. We show here that this separation of timescales is not possible for MEG solar cells, with Auger recombination, the inverse process to multi-exciton generation, needing to be considered explicitly in the efficiency limits of an MEG solar cell. We assess the impact of Auger recombination using a non-equilibrium model of a quantum dot solar cell that satisfies microscopic reversibility and can approximate experimental external quantum efficiency (EQE) curves of MEG solar cells. Recombination - both Auger and radiative - is treated in a quasi-equilibrium approach, which can be justified with a clear model for the separation of timescales. A key insight of this model is that the achievable voltage of the device, and hence the solar energy conversion efficiency, depends on the absolute values of the impact ionization rate and the rate at which electrons lose energy through phonon scattering. By contrast, the EQE profile at short circuit depends only on the ratio of these two rates. This shows that the potential of certain MEG solar cell approaches cannot be assessed from EQE improvements alone, which highlights the importance of considering non-equilibrium processes in models of solar energy conversion devices