Gli hedge fund: caratteristiche, impatto sui mercati e ruolo nelle crisi finanziarie

Gli hedge fund (HF) sono sempre pi`u diffusamente considerati responsabili delle crisi finanziarie che si sono susseguite nel corso degli ultimi decenni. La loro natura di segretezza e la fama di particolare propensione al rischio, unite ad un ampio ricorso alla leva finanziaria, fanno si che questi operatori siano spesso indicati come principale causa dellaumento della volatilit`a ed instabilit`a dei mercati o quantomeno in grado di accentuarne fortemente le turbolenze. Per comprenderne correttamente il ruolo nelle situazioni di stress dei mercati, il lavoro ne analizza dapprima la natura e le caratteristiche distintive: principali strategie di investimento adottate, modalit`a di misurazione delle performance, struttura organizzativa tipica. Si esaminano poi i vantaggi che tipicamente la dottrina e la prassi riconoscono alla loro operativit` a: efficienza dei prezzi, liquidit`a dei mercati, innovazione innanzitutto. Si analizzano inoltre gli aspetti critici connessi allattivit degli HF, soprattutto in relazione alle situazioni di turbolenza dei mercati finanziari. Questa analisi `e essenziale per comprenderne il ruolo nellattuale crisi globale. Lo studio si conclude con alcune riflessioni sul dibattito che divide la comunit finanziaria circa lopportunit`a di introdurre misure specifiche di regolamentazione anche per lindustria degli HF

Draft Seagrass Bibliography Data Base

The following report describes in detail the elements of a literature search performed for the Southwest Florida Water Management District (SWFWMD), Department of Surface Water Improvement and Management (SWIM). The work was performed in accordance with the agreement between the District and Mote Marine Laboratory (MML), and comprises Task 3.0 (Literature Search) of the project entitled, Tampa Bay Water Quality Assessment- Determination of Environmental Requirements of Selected Populations

Static and dynamic precipitation phenomena in laser powder bed-fused Ti6Al4V alloy

The present paper investigates static and dynamic precipitation phenomena in the Ti6Al4V alloy produced via laser-powder bed fusion, solubilized at 1050 degrees C and aged in the range of 450-650 degrees C. In relation to the distance from the platform on which the samples are disposed during the solution heat treatment, the microstructure varies from alpha-laths to alpha-colonies arranged in a Widmanstatten structure. The aging heat treatment at 450 degrees C promotes the formation of stacking faults into alpha-laths and the precipitation of alpha(2)-Ti3Al phases. SEM and TEM observations reveal that the density of precipitates increases after aging at 500 degrees C, while coarsening of the alpha-phase occurs only after aging heat treatment at 600 degrees C. Vickers microhardness measurements reveal different peak-aging conditions and show that the alloy is unstable at high temperatures (T > 450 degrees C), both in the case of static and dynamic precipitation phenomena. Only the aging profile at 450 degrees C shows a constant trend of Vickers microhardness after 4 h of treatment

Oxidation behaviour of nanostructured Ti-B-N based coatings

Nanostructured Ti-B-N based coatings are widely employed in many applications for the excellent propertiessuch as high hardness, low friction, good resistance to wear and corrosion. In addition, if some alloyingelements such Al and Si are incorporated an oxidation improved resistance is achieved. In the present work,Ti-B-N, Ti-Si-B-N and Ti-Al-Si-B-N coatings deposited by Ion Implantation Assisted Magnetron Sputtering(IIAMS) have been investigated. All the coatings were deposited on single-crystal Si-[100]. To evaluate theoxidation behavior, the coatings were annealed in air at 700 and 900°C for 4 hours. Ti-B-N coatings oxidizescompletely after annealing at 700°C for 4 hours, while a layered structure with well-definite interface isproduced on Ti-Si-B-N and Ti-Al-Si-B-N based coatings. Upon annealing at 900°C, the Si-doped film showedsignificantly better oxidation resistance compared to that of Ti-B-N and Ti-Al-Si-B-N coatings

Investigation of the temperature-relatedwear performance of hard nanostructured coatings deposited on a s600 high speed steel

Thin hard coatings are widely known as key elements in many industrial fields, from equipment for metal machining to dental implants and orthopedic prosthesis. When it comes to machining and cutting tools, thin hard coatings are crucial for decreasing the coefficient of friction (COF) and for protecting tools against oxidation. The aim of this work was to evaluate the tribological performance of two commercially available thin hard coatings deposited by physical vapor deposition (PVD) on a high speed tool steel (S600) under extreme working conditions. For this purpose, pin-on-disc wear tests were carried out either at room temperature (293 K) or at high temperature (873 K) against alumina (Al2O3) balls. Two thin hard nitrogen-rich coatings were considered: a multilayer AlTiCrN and a superlattice (nanolayered) CrN/NbN. The surface and microstructure characterization were performed by optical profilometry, field-emission gun scanning electron microscopy (FEGSEM), and energy dispersive spectroscopy (EDS).Funding: This research was made possible by an NPRP award NPRP 5-423-2-167 from the Qatar National Research Fund (a member of The Qatar Foundation)

Postnatal and postweaning endocrine setting in dairy calves through hair cortisol, dehydroepiandrosterone and dehydroepiandrosterone sulphate

Importance of the work: The care of calves on dairy farms between birth and weaning can improve their long-term development and growth. In fact, a poor newborn health status and a high allostatic load may adversely affect development in dairy cows. To determine cortisol, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulphate (DHEA-S) individually is useful for an understanding of the individual state, being biomarkers of hypothalamic-pituitary-adrenal (HPA) axis activity. Objectives: As a preliminary study, to investigate the hair concentrations of cortisol, DHEA, DHEA-S and their ratios in dairy calves in two key periods of their growth characterized by considerable environmental changes. Materials & Methods: Hair sampling was conducted on clinically healthy dairy calves during the postnatal period at age 64.8±0.65 d (POP; mean±standard error; n = 73) and during the postweaning period at age 155.3±0.85 d (PWP, n = 62). The hair hormone concentrations were measured using a radioimmunoassay. Results: Hair cortisol concentrations were higher in the POP than in the PWP. Furthermore, the cortisol:DHEA and cortisol:DHEA-S ratios were higher in the first period of evaluation, showing a higher animal allostatic load at birth. Main finding: Identification was achieved non-invasively of calves with a high allostatic load through biomarkers of HPA axis activity. The evaluation of this activity is very important given its influence on many biological processes, such as energy balance, development of the reproductive system and immune response

Mechanical and microstructure characterization of hard nanostructured N-bearing thin coating

Tools for machining are made of hard steels and cemented carbide (WC-Co). For specialized applications, such as aluminium machining, diamond or polycrystalline cubic boron nitride are also used. The main problem with steel, is that it exhibits a relatively low hardness (below 10GPa) which strongly decreases upon annealing above about 600K. Thus, the majority of modern tools are nowadays coated with hard coatings that increase the hardness, decrease the coefficient of friction and protect the tools against oxidation. A similar approach has been recently used to obtain a longer duration of the dies for aluminium die-casting. Multi-component and nanostructured materials represent a promising class of protective hard coatings due to their enhanced mechanical and thermal oxidation properties. Surface properties modification is an effective way to improve the performances of materials subjected to thermo-mechanical stress. Three different thin hard nitrogen-rich coatings were mechanically, microstructurally, and thermally characterized: a 2.5 micron-thick CrN-NbN, a 11.7 micron-thick TiAlN, and a 2.92 micron-thick AlTiCrxNy. The CrN-NbN coating main feature is the fabrication by the alternate deposition of 4nm thick-nanolayer of NewChrome (new type of CrN, with strong adhesion and low coating temperature). All the three coatings can reach hardness and elastic modulus in excess of 20, and 250 GPa, respectively. Their main applications include stainless steel drawing, plastic materials forming and extrusion and aluminum alloys die-casting. The here studied TiAlN (SBN, super booster nitride) is one of the latest evolution of TiAlN coatings for cutting applications, where maximum resistance to wear and oxidation are required. The AlTiCrxNy combines the very high wear resistance characteristic of the Cr-coatings and the high thermal stability and high-temperature hardness typical of Al-containing coatings. All the coatings were deposited on a S600 tool steels. The coatings were subjected to two different thermal cycling tests: one for 100 thermal cycles consisting of 60 s dwelling time, respectively at the high- (573 to 1173 K) and at the room-temperature, a second for 100 thermal cycles consisting of 115s dwelling time, at same temperatures of the first test, followed by 5s dwelling at room-temperature. The investigated coatings showed a sufficient-to-optimal thermal response in terms of stability of hardness, elastic modulus, and oxidation behavior. The temperature induced hardness and elastic modulus coating variations were measured by nanoindentation.NPRP grant # NPRP5–423–2–167, from the Qatar National Research Fund (a member of Qatar Foundation

Microstructure studies on a MG-AL-SI alloy (AS21X)

The microstructure in a crept AS21X was investigated; ?-Mg17Al12 , Mg2Si and ?'-(Mn, Fe)(Al, Si) particles were observed alongside with extensive twinning and dislocation pile-ups against grain boundaries

Plant biodiversity of mountain grasslands as influenced by dairy farm management in the Eastern Alps

It has been widely demonstrated that farm management affects the plant species composition of grassland. The present study aimed to investigate the effect of farm management on plant species richness and composition in forty-nine small-scale farms breeding dairy cattle, located in the Eastern Italian Alps at two levels of precision: plot and farm levels. Data on housing system, quality scheme, farm productivity, income from milk yield and livestock density were collected through interviews with farmers. In each farm, botanical surveys were carried out in different plots representing the botanical composition of the farmland vegetation. Elevation, slope, type of use, number of hay cuts and type of fertilisation were also recorded. The botanical surveys of the plots on each farm were analysed to describe plant composition at the plot level, then merged to describe plant composition at the farm level. At both levels, grassland botanical composition was found to be affected by farm management. At the plot level, meadows cut 2 and 3 times per year did not exhibit any differences in plant richness, but they differed in plant species, botanical family and phytosociological class composition, with a general simplification of botanical composition. We found fewer phytosociological classes but not fewer plant species or botanical families in plots fertilised with slurry than in plots fertilised with manure or not fertilised, and a change in the botanical composition due to changes in the relative abundance of plant species. At the farm level, we observed a decrease in the number of plant species and phytosociological classes, and changes in plant composition, with increasing milk yield and livestock density. Changes in botanical composition were less evident at the farm level than at the plot level. However, protecting farms and their economic viability is a means of maintaining biodiversity at the plot level