We present a fast N log N time algorithm for computing quadratic-phase integrals. This three-parameter class of integrals models propagation in free space in the Fresnel approximation, passage through thin lenses, and propagation in quadratic graded-index media as well as any combination of any number of these and is therefore of importance in optics. By carefully managing the sampling rate, one need not choose N much larger than the space-bandwidth product of the signals, despite the highly oscillatory integral kernel. The only deviation from exactness arises from the approximation of a continuous Fourier transform with the discrete Fourier transform. Thus the algorithm computes quadratic-phase integrals with a performance similar to that of the fast-Fourier-transform algorithm in computing the Fourier transform, in terms of both speed and accuracy. A quadratic-phase system is a unitary system whose output g͑u͒ is related to its input f͑u͒ through a quadratic-phase integral:where ␣, , and ␥ are real parameters. This relationship is also known by other names, including "linear canonical transforms." [1][2][3][4] This input-output relation can model a broad class of optical systems, including thin lenses, sections of free space in the Fresnel approximation, sections of quadratic graded-index media, and arbitrary concatenations of any number of these. 2,3Computation of the Fresnel diffraction integral, which is a special case of Eq. (1) with ␣ =  = ␥, has received the greatest attention because it describes the propagation of light in free space (see Refs. 5 and 6 and the references therein). As the input-output relationship represented by the Fresnel integral is space invariant and takes the form of a convolution, one can compute it by taking the Fourier transform (FT) of the input, multiplying by the transfer function of free space, and inverse transforming, with overall time ϳN log N. Here we present an algorithm with which to compute Eq. (1) in ϳN log N time, despite the fact that the relationship represented by the more general Eq. (1) is not space invariant and is not a convolution. It is important to underline that here N is chosen close to the space-bandwidth product of the set of input signals, which is usually the smallest possible value of N that can be chosen in terms of information-theoretic considerations. Therefore the algorithm is highly efficient and, although we do not present a formal proof of this, is quite possibly nearly the most efficient that is possible. Indeed, the distinguishing feature of the present approach is the care with which sampling and space-bandwidth product issues are handled. Straightforward use of conventional numerical methods can result in inefficiencies either because their complexity is larger than ϳN log N or because the highly oscillatory quadraticphase kernel in Eq. (1) forces N to be chosen much larger than the space-bandwidth product of the signals.In the method presented here, the samples of the output are computed in terms of the samples of the input, in the sa...
ÖzetBruselloz özellikle ülkemizin doğu ve güneydoğu kesimlerinde endemik olarak görülen önemli bir enfeksiyon hastalığıdır. Bu makalede çocuklarda brusellozun klinik ve laboratuvar bulgularının ve tedavi sonuçlarının etkinliğini değerlendirmek amaçlandı.Eylül 2010 ile Şubat 2011 tarihleri arasında yaklaşık 6 aylık dönemde çocuk polikliniğine bruselloz düşündüren şikayetlerle başvuran çocuklar tetkik edildi. Tetkik edilen hastaların 43'üne bruselloz tanısı konuldu ve başvuru şikayetleri, fizik muayene bulguları ve laboratuvar sonuçları değerlendirildi. Olguların 22'si erkek (%51) olup ortalama yaşları 9.3 yaş (4 yaş-13 yaş) arasında idi. En sık başvuru yakınmaları; halsizlik olguların tamamı (%100), kas ağrısı olguların tamamı (%100) ve kilo kaybı (%86) idi. Olguların fizik muayenelerinde; artrit (%48), lenfadenopati (%6) ve splenomegali (%13) saptandı. Laboratuvar bulgularında olguların %51'inde sedimantasyon yüksekliği, %65'inde ALT/AST yüksekliği ve %72'sinde ise CRP pozitifliği vardı. Brusella aglütinasyon testleri olguların tamamında pozitifti. Kan kültüründe üreme olguların %6'sında tespit edildi. Olguların tamamına en az ikili antibiyotik tedavisi verildi. Rölaps %11 (n=5) oranında görüldü, mortalite gözlenmedi. Bruselloz özellikle hastalığın yaygın olduğu bölgelerde sağlık ekiplerinin üzerinde durması gereken ve koruyucu tedbirlerin alınması ve etkin tedavinin uygulanması gereken toplum sağlığı problemidir. Anahtar kelimeler: Bruselloz; çocuk; laboratuvar bulguları; tedavi. AbstractBrucellosis is an important infectious disease especially endemic in Eastern and Southeastern Turkey. In this study, we aimed to evaluate the clinical, laboratory and treatment results of Brucellosis in children. Children with nonspecific findings suggestive of Brucellosis were included from September 2010 to February 2011 from the outpatient clinic. The symptoms, physical findings and laboratory values are analyzed in 43 children who were diagnosed as Brucellosis.The mean age of children was 9.3 years (range: 4-13 years), 51%n:22) were male. Most common complaint was fatigue (100%), myalgia (100%) and weight loss (86%). Arthritis (48%), lymphadenopathy (6%), and splenomegaly (13%) has been identified. Laboratory values revealed high sedimentation rates (51%), high AST/ALT (65%), high CRP levels (72%). Brucella agglutination test was positive in all of the patients. Brucella was identified in 6% of blood cultures. All of the patients were treated with antibiotics of least two-drug combination. The relapse rate was 11% (n=5) and no mortality was observed. Brucellosis is an important health issue, especially in endemic regions, necessitating preventive measures and effective treatment.
Cefoperazone/sulbactam can be used in the treatment of nosocomial infections caused by multidrug-resistant pathogens in neonates.
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