385 research outputs found
What discount rates should the Public Sector adopt in a Public-Private Partnership?
Mestrado em CiĂȘncias EmpresariaisO conceito de parcerias pĂșblico - privadas tem chamado a atenção dos economistas e Governos nas Ășltimas dĂ©cadas, onde sucessos e fracassos coexistem em todo o Mundo na esperança de atingir o Value for Money. A definição, conceitos e os objectivos das parcerias pĂșblico -privadas serĂŁo abordadas na generalidade da tese. A taxa de desconto que o sector pĂșblico deverĂĄ adoptar numa parceria deste tipo Ă© uma discussĂŁo global e a questĂŁo principal abordada nesta tese. NĂŁo serĂĄ concluĂdo se a parceria pĂșblico - privada deveria ser ou nĂŁo realizada. HĂĄ muitas perspectivas diferentes relativas Ă s vĂĄrias taxas de desconto a utilizar, mas, neste caso, apenas serĂŁo abordadas trĂȘs taxas distintas e serĂĄ construĂda e analisada uma estimativa relativa ao valor actual dos pagamentos futuros efectuados pelo Governo Ă s empresas privadas que tĂȘm contractos no formato de parceria pĂșblico - privada.The concept of Public Private Partnerships has brought attention to the economists and Public Parties on the last few decades, where success and failure have occurred all over the world, where Governments search for the objective of Value for Money. We will define what a Public Private Partnership is and what are their main goals and conceptions. What discount rate should the Public Sector adopt in a Public Private Partnership is a global discussion nowadays and the main issue on this paper. We will not consider if a Public Private Partnership should or should not be realized, on the other hand we will try to create some scenario basis for the Portuguese experience. There are many different approaches and in this paper we will take a look to three different approaches and develop an estimate through the future payments in the next 50 years of Portuguese governments' payments to the private sector
Automist - A Tool for Automated Instruction Set Characterization of Embedded Processors
The steadily increasing performance of mobile devices also implies a rise in power consumption. To counteract this trend it is mandatory to accomplish software power optimizations based on accurate power consumption models characterized for the processor. This paper presents an environment for automated instruction set characterization based on physical power measurements. Based on a detailed instruction set description a testbench generator creates all needed test programs for a complete characterization. Afterwards those programs are executed by the processor and the energy consumption is measured. For an accurate energy measurement a high performance sampling technique has been established, which can be either clock or energy driven
Probiotic Microorganisms in Dry Fermented Meat Products
In the modern lifestyle, food is supposed not only to feed the hunger but also to provide an appropriate amount and quality of nutrients necessary for proper functioning of the body. The interest of consumers in functional food, including fermented products with probiotic properties, has been growing for several years. Meat and meat products represent one of the most important components of contemporary human diet. Meat fermentation is one of the oldest methods of preserving food. This is a lowâenergy, biological acidulation which results in unique flavour and palatability, colour, microbiological safety and tenderness. Changes of muscle form into fermented meat product are caused by homoâ or heterofermentative starter cultures or âwildâ microorganisms which lower the pH. Fermented meat products are one of the most cherished and valuable food products. Fermentation and ageing process would deliver most aromatic and rich in flavour products, which is incomparable with other processes. A new solution is dryâaged meats with the use of new probiotic starter cultures with a high degree of health safety and long shelf life due to the inhibition of growth of the pathogenic microorganisms and therefore reduction of the formation of harmful compounds from protein transformation or lipid oxidation
Methodologies for Designing Power-Aware Smart Card Systems
Smart cards are some of the smallest
computing platforms in use today. They have
limited resources, but a huge number of
functional requirements. The requirement for
multi-application cards increases the demand
for high performance and security even more,
whereas the limits given by size and energy
consumption remain constant.
We describe new
methodologies for designing and implementing
entire systems with regard to power awareness
and required performance. To make use of this
power-saving potential, also the higher layers
of the system - the operating system layer and
the application domain layer - are required to
be designed together with the rest of the
system.
HW/SW co-design methodologies enable the gain of
system-level optimization. The first part presents the
abstraction of smart cards to optimize system architecture
and memory system. Both functional and transactional-level
models are presented and discussed. The proposed design
flow and preliminary results of the evaluation are depicted.
Another central part of this methodology is a cycle-accurate instruction-set
simulator for secure software development.
The underlaying energy model is designed
to decouple instruction and data dependent energy dissipation,
which leads to an independent characterization process and allows
stepwise model refinement to increase estimation accuracy. The
model has been evaluated for a high-performance smart card CPU and
an use-case for secure software is given
Amides as Non-polymerizable Catalytic Adjuncts Enable the Ring-Opening Polymerization of Lactide With Ferrous Acetate Under Mild Conditions
Sn-based catalysts are effective in the ring-opening polymerization (ROP) but are toxic. Fe(OAc)2 used as an alternative catalyst is suitable for the ROP of lactide only at higher temperatures (>170°C), associated with racemization. In the ROP of ester and amide group containing morpholinediones with Fe(OAc)2 to polydepsipeptides at 135°C, ester bonds were selectively opened. Here, it was hypothesized that ROP of lactones is possible with Fe(OAc)2 when amides are present in the reactions mixture as Fe-ligands could increase the solubility and activity of the metal catalytic center. The ROP of lactide in the melt with Fe(OAc)2 is possible at temperatures as low as 105°C, in the presence of N-ethylacetamide or N-methylbenzamide as non-polymerizable catalytic adjuncts (NPCA), with high conversion (up to 99 mol%) and yield (up to 88 mol%). Polydispersities of polylactide decreased with decreasing reaction temperature to †1.1. NMR as well as polarimetric studies showed that no racemization occurred at reaction temperatures â€145°C. A kinetic study demonstrated a living chain-growth mechanism. MALDI analysis revealed that no side reactions (e.g., cyclization) occurred, though transesterification took place
Compiler-based Software Power Peak Elimination on Smart Card Systems
RF-powered smart cards are widely used in different application areas today. For smart cards not only performance is an important attribute, but also the power consumed by a given application. The power consumed is heavily depending on the software executed on the system. The power profile, especially the power peaks, of an executed application influence the system stability and security. Flattening the power profile can thus increase the stability and security of a system.
In this paper we present an optimization system that allows a reduction of power peaks based on a compiler optimization. The optimizations are done on different levels of the compiler. In the backend of the compiler we present new instruction scheduling algorithms. On the intermediate language level we propose the use of iterative compiling for reducing critical peaks
Perfluorophenyl azide functionalization of electrospun poly(paraâdioxanone)
Strategies to surfaceâfunctionalize scaffolds by covalent binding of biologically active compounds are of fundamental interest to control the interactions between scaffolds and biomolecules or cells. Poly(paraâdioxanone) (PPDO) is a clinically established polymer that has shown potential as temporary implant, eg, for the reconstruction of the inferior vena cava, as a nonwoven fiber mesh. However, PPDO lacks suitable chemical groups for covalent functionalization. Furthermore, PPDO is highly sensitive to hydrolysis, reflected by short in vivo halfâlife times and degradation during storage. Establishing a method for covalent functionalization without degradation of this hydrolyzable polymer is therefore important to enable the surface tailoring for tissue engineering applications. It was hypothesized that treatment of PPDO with an Nâhydroxysuccinimide ester group bearing perfluorophenyl azide (PFPA) under UV irradiation would allow efficient surface functionalization of the scaffold. Xâray photoelectron spectroscopy and attenuated total reflectance Fourierâtransformed infrared spectroscopy investigation revealed the successful binding, while a gel permeation chromatography study showed that degradation did not occur under these conditions. Coupling of a rhodamine dye to the Nâhydroxysuccinimide esters on the surface of a PFPAâfunctionalized scaffold via its amine linker showed a homogenous staining of the PPDO in laser confocal microscopy. The PFPA method is therefore applicable even to the surface functionalization of hydrolytically labile polymers, and it was demonstrated that PFPA chemistry may serve as a versatile tool for the (bioâ)functionalization of PPDO scaffolds
Functionalizable coaxial PLLA/PDLA nanofibers with stereocomplexes at the internal interface
Multifunctionality of electrospun polylactic acid (PLA) nonwovens was generated by the morphological design of nanofibers. Coaxial fibers with a lower number average molar mass Mn PLLA core and a higher Mn PDLA shell form PDLAâPLLA stereocrystals at the interface, induced by annealing. In tensile tests under physiological conditions, the coreâshell fibers with higher crystallinity (22% compared to 11â14%) had lower Youngâs moduli E (9â±â1 MPa) and lower elongation at break Δb (26â±â3%) than PDLA alone (Eâ=â31â±â9 MPa, Δbâ=â80â±â5%), which can be attributed to simultaneous crystallization and relaxation effects. Gelatin incorporated in the PDLA phase was presented on the outer surface providing a biointerface putatively favorable for cell adherence. Gelatin incorporation did not influence the crystallization behavior but slightly lowered Tg (60 â 54 °C). Employing exclusively polymers established in the clinic, multifunctionality was generated by design
RGD constructs with physical anchor groups as polymer co-electrospinnable cell adhesives
The tissue integration of synthetic polymers can be promoted by displaying RGD peptides at the biointerface with the objective of enhancing colonization of the material by endogenous cells. A firm but flexible attachment of the peptide to the polymer matrix, still allowing interaction with receptors, is therefore of interest. Here, the covalent coupling of flexible physical anchor groups, allowing for temporary immobilization on polymeric surfaces via hydrophobic or dipoleâdipole interactions, to a RGD peptide was investigated. For this purpose, a stearate or an oligo(ethylene glycol) (OEG) was attached to GRGDS in 51â69% yield. The obtained RGD linker constructs were characterized by NMR, IR and MALDI-ToF mass spectrometry, revealing that the commercially available OEG and stearate linkers are in fact mixtures of similar compounds. The RGD linker constructs were co-electrospun with poly(p-dioxanone) (PPDO). After electrospinning, nitrogen could be detected on the surface of the PPDO fibers by X-ray photoelectron spectroscopy. The nitrogen content exceeded the calculated value for the homogeneous material mixture suggesting a pronounced presentation of the peptide on the fiber surface. Increasing amounts of RGD linker constructs in the electrospinning solution did not lead to a detection of an increased amount of peptide on the scaffold surface, suggesting inhomogeneous distribution of the peptide on the PPDO fiber surface. Human adipose-derived stem cells cultured on the patches showed similar viability as when cultured on PPDO containing pristine RGD. The fully characterized RGD linker constructs could serve as valuable tools for the further development of tissue-integrating polymeric scaffolds
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