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La crisi dei mutui subprime: analisi degli effetti sui rendimenti e sul rischio sistematico nel mercato immobiliare
Full text linkNel paper si analizza lâ effetto che ha avuto la crisi dei subprime sui titoli del comparto
immobiliare nel mercato USA, epicentro dellâ attuale crisi economica mondiale.
Tramite il modello a tre fattori di Fama e French si studia la relazione tra lâ extra
rendimento dellâ indice REIT, considerato una proxy dellâ andamento dei titoli
immobiliari americani, e lâ extra rendimento dellâ indice S&P500, considerato una
proxy del rendimento del portafoglio di mercato. Si riscontra un aumento del
coefficiente di regressione (il beta) nellâ anno 2007 seguito da un ritorno ai valori
iniziali nellâ anno 2009 e la possibile presenza di break strutturali.
I risultati tendono a confermare la presenza di un â Asymmetric REIT Beta Puzzleâ
precedentemente analizzato in letteratura.This paper analyzes the effects of the subprime crisis on U.S. Real Estate Stocks,
which plays a significant role in the current crisis. By analyzying, by means of the
Fama & French three factor model, the return on the REIT index, which is considered
a proxy for the U.S. Real Estate securities trend, and the return on the S&P500 yield,
which may be interpreted as a proxy for U.S. market portfolio. I found evidence of an
increase in the beta coefficient in 2007 followed by a reversion to the initial value in
2009. Moreover, I found evidence of the presence of structural breaks. The results
tend to confirm the presence of the â Asimmetric REIT Beta Puzzleâ , previously
analyzed in literature
Accuracy in the Gupta method of optical constant determination
No full textThe Gupta method leads to the determination of the optical constants of an absorbing material through Iwo measurements of reflecljvity. In this paper, the effect of experimental errors on both the accuracy of the determination and the conditions for the achievement of unambiguous results is studied
Conformational analysis of DNA-basic polypeptide complexes: possible models of nucleoprotamines and nucleohistones
No full text
Epidemiologic study on clavicular fractures
No full textIntroduction: Fracture of clavicle is common, accounting for 5% to 12% of all fractures and up to 44% of injuries to the shoulder. Surprisingly,only one study was performed on a large and significative number of patients, however,it was carried out on
subjects of a little harbour city (200,000 inhabitants) whose life customs are different with respect to those of metropolitan people. Other data that emerge from investigations performed on a low number of patients are in contrast among them.We
have carried out an epidemiological study regarding prevalence and causes of the clavicular fractures occurred in patients of a wide district of our town.
Methods: Clinical records of patients who sustained, between 1981-1984 and
1990-1999 clavicular fractures, treated at our Institute,have been analyzed. Information on patient's age and causes responsible of the fracture was obtained. X-ray films,
documenting the fracture, were separately examined by two of the authors. Fractures
were classified according to Allman’s method(1967); those associated with AC or sternoclavicular dislocation were excluded. Statistical analysis was performed with the use
of Chi-squared test.
Results: Of the 20,094 patients treated at our emergency repart for a fracture during the studied period,526(2.6%) sustained a clavicular fracture (bilaterally in two cases)
(44.1% of injuries to the shoulder)p=0.001. Of the 526 patients,354 (67.3%) were
males (p:0.001). 431 fractures(81 .6%) belonged to Type I fracture (middle shaft); of
them,143 (33%) and 206 (47.8%) had, respectively, no (la) and displacement (lb) of
bone fragments; while 81 (18.8%) were comminuted fractures(Ic) (p=0.001). Of the
remaining fractures,87(16.4%) belonged to Type ll fractures (distal clavicular fracture)
(47.7% and 52.3% were not displaced and displaced fractures respectively;p=0.8).
Only 10 patients (1 .6%) had fractures of the proximal third (Type lll): undisplaced in
3 cases (llla) and displaced in 7 (lllb).l\/lean age of patients with Type l,Il and Ill fractures was, respectively 26,37 and 51 yrs; while that of patients with undislaced and
displaced fractures was 24 and 31 yrs.Prevalence of Type l fracture decreased with
age; while Type ll and lll fractures always increased in patients older than 60 years
old. A half(47.3%) of clavicular fractures occurred as a consequence of traffic accidents especially injuries resulting from falls from mopeds. No significant difference
was observed regarding seasonal prevalence of clavicular fractures.
Conclusion: In our series, prevalence of clavicular fracture is about one half compared
to Nordqvist and Petersson’s study. This discrepancy is probably due to different char-
acteristics of examined cohorts, mean age,sportive lifestyle, greater use of bycicle as
mean of trasportation. Furthermore, two thirds of our patients had a displaced frac-
ture. This frequency is higher than that revealed by Nordqvist and Petersson(42.7%),
probably because our prevalence of Type l fracture, that usually undergoes displace-
ment, was higher. Previous studies referred that 50%-82% of all fractures belongs
to Type I, 10%-18% to Type ll and 2%-10% to Type lll. these proportions are in accordance with ours. our data suggest a significant correlation between age, localization of the fracture and entity of displacement. In fact, 94% of the fractures sustained by children (<10yrs) belonged to Type I fracture and two thirds were undisplaced. type I fractures were the more frequent also in adolescents and young adults, however 71% had a displacement of bone fragments. Finally , in the elderly a low prevalence of clavicular was revealed; probably because the trauma exhaust itself in common osteoporotic areas (humeral head, wrist
Latissimus dorsi transfer for primary treatment of irreparable rotator cuff tears
No full textAbstract Tratisfer of the musculotendinous unit of the latissimus dorsi
was performed in seven patients (5
men and 2 women, with a mean age
of 57 years) with irreparable rotator
cuff tear who had had no previous
surgery for cuff repair.
Preoperatively, the mean active
shoulder motion was 86° in flexion,
74° in abduction and 22° in external
rotation. One patient had a positive
lift-off test. The average preoperative
Constant and Murley score was
44%. Diagnosis of irreparability of
the cuff lesion was made preoperatively only in one case. In the
remaining patients, the preoperative
data only led to suspect that the tear
was irreparable. At surgery, all
patients had an irreparable tear of the
superoinferior portion of the cuff and
one patient also had a tear of the
subscapularis tendon. In all cases the
latissimus dorsi tendon was inserted
to the greater tuberosity and, in four
cases, to the subscapularis tendon; in
three patients it was sutured to the
bicipital tendon. Postoperatively all
patients had relief of shoulder pain.
The mean improvement in active
flexion, abduction and external rotation was, respectively, 39°, 29® and
10°. At the latest follow-up, the average Constant and Murley score was
64%. The results of surgery were
rated as excellent in three cases,
good in two, fair in one and poor in
one. All patients but one returned to
preoperative work. Transfer of the
latissimus dorsi muscle is an effective procedure for patients in middle
or early elderly age who have an
irreparable tear of the supraspinatus
and infraspinatus tendons
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