Feasibility analysis of correlation based prefetching using digital signal processing

As the gap between processor performance and memory performance continues to broaden with time, techniques to hide memory latency such as correlation based prefetching become exceedingly important. When a memory reference issued by the processor misses the level one cache, the request propagates down the memory hierarchy until it finally finds the requested datum. With each layer traversed, the latency grows exponentially. Prefetching is a technique used to hide this latency by attempting to predict which memory references will be requested in the near future, and then load them into cache before they are needed. This work investigates the use of digital signal processing techniques in designing an effective prefetch algorithm. The algorithm proposed in this work uses the Kalman Filter as the basic digital signal processing block. The sequence of memory address references with respect to time is interpreted as a digital signal. By applying Kalman filtering techniques, a robust prediction algorithm is presented to predict future miss references based on the pattern of previous miss references. The algorithm was simulated using 40 benchmark programs from the Olden, MediaBench, and SPEC benchmark suites for the Alpha 21264 and the PISA (a MIPS-like ISA) instruction set architectures. A main difference between these two ISAs is that the Alpha 21264 ISA contains software prefetch instructions, and the PISA instruction set architecture does not. The simulations place a prefetcher unit between the level one data cache and the level two unified cache. SimpleScalar simulation results for a broad set of benchmark programs using 32 Kalman filter blocks show an average of 6.5% speedup for the Alpha 21264 ISA, and an average of 5.6% speedup for the PISA instruction set architecture for those benchmark programs which have a potential speedup from prefetching greater than 10%

Two-photon ionization spectroscopy and all-electron ab initio study of LiCa

Journal ArticleResonant two-photon ionization spectra of LiCa have been obtained from a laser vaporization, supersonic expansion source. The ground state of the molecule is confirmed to be X 2?+. Three band systems have been observed near 15 282, 19 310, and 22 250 cm-1 and the upper states have been assigned as 2?+, 2IIr , and, tentatively, 2II. Bond lengths and vibrational frequencies are reported for 7Li40Ca for the various states as X 2?+: r0=3.3796(11) ?, D?1/2=195.2 cm21; 2?+: r0=3.4275(47) ?, D?1/2=283.5 cm-1; 2IIr : re=3.5451(36) ?, ve5144.5 cm-1; and 2II: ve 5178.53(5) cm21. The ionization energy was also measured to be 4.471(1) eV by observing the onset of one-photon ionization. Results of ab initio all-electron calculations on twelve low-lying states [2?+(1), 2?+(2), 2?+(3), 2?+(4), 4?-(1), 4?-(1), 2II(1), 2II(2), 2II(3), 2II(4), 4II(1), and 4II(2)] are also reported, along with results on the X 1?+ ground electronic state of LiCa1. The dissociation energies of LiCa(X 2?+) into Li(2S)1Ca(1S) and of LiCa1 (X 1?+) into Li1(1S)1Ca(1S) are calculated to be 0.24 and 1.20 eV respectively, and the vertical and adiabatic ionization energies of LiCa have been determined to be almost the same, 4.43 eV, at the quadratic configuration interaction, including singles and doubles with approximate triples and all correlated electrons [QCISD(T,FULL)] level of theory

Public Health Disaster Research: Surveying the Field, Defining its Future

Disaster medicine and public health preparedness are commonly perceived as subfields of the larger fields of medicine and public health rather than being recognized as an emerging academic field embracing all of the disciplines that contribute to effective disaster response. As such, they serve as appropriate subjects for multidisciplinary work in the social sciences, whether it is a sociological analysis of mass behavior during a disaster, psychological studies of the willingness to work of various workforces, or organizational theory or network analyses applied to ad hoc disaster coalitions. Laboratory sciences and bioinformatics contribute as well to the development of new treatment modalities, medical products, and surveillance technologies. As is true in the broader medical and public health fields, much of the work is empirical and evaluative. In this article, the authors survey the literature in the field and suggest that broader, more ecologically based research is needed

Angioedema Presenting As Chronic Gastrointestinal Symptoms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72177/1/j.1572-0241.1993.tb07563.x.pd

Pilot istraživanje Clostridium difficile infekcija u bolesnika s proljevom u zdravstvenim ustanovama u Tbilisiju, Gruzija

Background: Clostridium difficile infection (CDI) is the most frequent cause of healthcare-associated diarrhoea and is increasingly recognized in the community. The epidemiology of CDI in Georgia is unknown. Methods: Pilot surveillance for CDI among patients with diarrhoea was conducted in four hospital ICUs, and three outpatient clinics in Tbilisi, Georgia. Demographic, clinical and treatment data of patients with CDI were collected from medical records. A CDI diagnosis was made if the stool sample was positive for C. difficile toxin A and/or B by nucleic acid amplification test or enzyme immunoassay, or by culture of a toxin-producing C. difficile. Results: A total of 131 patients with new onset diarrhoeal illness were recruited. Of these, laboratory confirmed CDI was found in 24% (31/131): 32% (17/53) of adult and 20% (11/55) of paediatric ICU patients, 22% (2/9) adult and 7% (1/14) of paediatric outpatients. Presenting symptoms were fever (>380C) and diarrhoea with a median duration 7 days. Most CDI cases received antibiotics before diagnosis; 94% of adults and 91% of children diagnosed in the ICU (median: 12 days); the majority receiving simultaneously two or more antibiotics. In the outpatient settings, 100% of CDI case-patients received an antibiotic for a median duration of 7 days. Conclusions: This pilot surveillance demonstrated that C. difficile is a common cause of diarrhoea in hospitalized and community patients in Georgia. It highlights the need to improve the knowledge of medical providers regarding the burden of CDI and to establish diagnostic testing at hospital laboratories.Uvod: Infekcije uzrokovane Clostridium difficile (CDI) najčešći su uzrok proljeva povezanog sa zdravstvenom skrbi i sve se više prepoznaju u zajednici. Epidemiologija C.difficile infekcija u Gruziji nije poznata. Metode: Pilot istraživanje C.difficile infekcija kod bolesnika s proljevom provedeno je u četiri bolničke jedinice za intenzivno liječenje (JIL) i tri ambulantne klinike u Tbilisiju u Gruziji. Podaci o demografskim i kliničkim karakteristikama te liječenju bolesnika s CDI prikupljeni su iz povijesti bolesti. Dijagnoza C.difficile infekcije postavljena je ukoliko je uzorak stolice bio pozitivan na C. difficile toksin A i/ili B testom amplifikacije nukleinskih kiselina ili metodom enzimskog imunoeseja ili nalazom C. difficile koji proizvode toksine u kulturi. Rezultati: U istraživanje je bio uključen 131 bolesnik s novonastalom dijarealnom bolesti. Od toga je laboratorijski dokazana CDI utvrđena kod 24% (31/131) bolesnika: u 32% (17/53) odraslih i 20% (11/55) djece liječene u JIL-u, 22% (2/9) odraslih i 7% (1/14) pedijatrijskih ambulantnih bolesnika. Simptomi su bili povišena tjelesna temperatura (> 38 ° C) i proljev s prosječnim trajanjem od 7 dana. Većina bolesnika s CDI primila je antibiotik prije postavljanja dijagnoze; 94% odraslih i 91% djece liječene u JIL-u (medijan: 12 dana); većina je istodobno primala dva ili više antibiotika. U ambulantnom okruženju, 100% bolesnika s CDI primilo je antibiotik u prosječnom trajanju od 7 dana. Zaključak: Ovo pilot istraživanje pokazalo je da je C. difficile čest uzrok proljeva u hospitaliziranih i izvanbolničkih pacijenata u Gruziji. Ono naglašava potrebu za poboljšanjem znanja pružatelja zdravstvenih usluga vezano uz probleme koje nose infekcije uzrokovane C. difficile te uspostavom dijagnostičkih testova u bolničkim laboratorijima

A current-voltage model for Schottky-barrier graphene based transistors

A low complexity computational model of the current-voltage characteristics for graphene nano-ribbon (GNR) field effect transistors (FET), able to simulate a hundred of points in few seconds using a PC, is presented. For quantum capacitance controlled devices, self-consistent calculations of the electrostatic potential can be skipped. Instead, analytical closed-form electrostatic potential from Laplace's equation yields accurate results compared with that obtained by self-consistent Non-Equilibrium Green's Functions (NEGF) method. The model includes both tunnelling current through the Schottky barrier (SB) at the contact interfaces and thermionic current above the barrier, properly capturing the effect of arbitrary physical and electrical parameters.Comment: 8 pages, 4 figure

Structure and properties of DOTA-chelated radiopharmaceuticals within the 225Ac decay pathway

The successful delivery of toxic cargo directly to tumor cells is of primary importance in targeted (α) particle therapy. Complexes of radioactive atoms with the 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelating agent are considered as effective materials for such delivery processes. The DOTA chelator displays high affinity to radioactive metal isotopes and retains this capability after conjugation to tumor targeting moieties. Although the α-decay chains are well defined for many isotopes, the stability of chelations during the decay process and the impact of released energy on their structures remain unknown. The radioactive isotope 225Ac is an α-particle emitter that can be easily chelated by DOTA. However, 225Ac has a complex decay chain with four α-particle emissions during decay of each radionuclide. To advance our fundamental understanding of the consequences of α-decay on the stability of tumor-targeted 225Ac–DOTA conjugate radiopharmaceuticals, we performed first principles calculations of the structure, stability, and electronic properties of the DOTA chelator to the 225Ac radioactive isotope, and the initial daughters in the decay chain, 225Ac, 221Fr, 217At and 213Bi. Our calculations show that the atomic positions, binding energies, and electron localization functions are affected by the interplay between spin–orbit coupling, weak dispersive interactions, and environmental factors. Future empirical measurements may be guided and interpreted in light of these results