4,499 research outputs found
A comparative study of the public relations programs and policies in schools and businesses
Thesis (Ed.M.)--Boston Universit
A potential model of fusion with transmission coefficients calculated by the matrix method
A barrier penetration model of heavy-ions fusion is presented. To calculate the transmission
coefficients through any one-dimensional barrier of nucleus-nucleus real potential
a matrix method is used. The parameters of the model are the critical radius and the parameters
of nuclear interaction. The model is tested on several cases oi fusion, i.e. a + 40,44Ca,
12C + 12C, 160 + 160 and 12C + 24Mg and it is found to reproduce the data quite well
Faddeev study of heavy baryon spectroscopy
We investigate the structure of heavy baryons containing a charm or a bottom
quark. We employ a constituent quark model successful in the description of the
baryon-baryon interaction which is consistent with the light baryon spectra. We
solve exactly the three-quark problem by means of the Faddeev method in
momentum space. Heavy baryon spectrum shows a manifest compromise between
perturbative and nonperturbative contributions. The flavor dependence of the
one-gluon exchange is analyzed. We assign quantum numbers to some already
observed resonances and we predict the first radial and orbital excitations of
all states with or 3/2. We combine our results with heavy quark
symmetry and lowest-order SU(3) symmetry breaking to predict the masses and
quantum numbers of six still non-measured ground-state beauty baryons.Comment: 22 pages, 4 figures, 8 tables. Accepted for publication in J. Phys.
"Spice", "Kryptonite", "Black Mamba": An overview of brand names and marketing stragtegies of Novel Psychoactive Substances on the Web
Novel Psychoactive Substances (NPSs) are often sold online as “legal” and “safer” alternatives to International Controlled Drugs (ICDs) with captivating marketing strategies. Our aim was to review and summarize such strategies in terms of the appearance of the products, the brand names, and the latest trends in the illicit online marketplaces. Methods: Scientific data were searched in PsychInfo and Pubmed databases; results were integrated with an extensive monitoring of Internet (websites, online shops, chat rooms, fora, social networks) and media sources in nine languages (English, French, Farsi, Portuguese, Arabic, Russian, Spanish, and Chinese simplified/traditional) available from secure databases of the Global Public Health Intelligence Network. Results: Evolving strategies for the online diffusion and the retail of NPSs have been identified, including discounts and periodic offers on chosen products. Advertisements and new brand names have been designed to attract customers, especially young people. An increased number of retailers have been recorded as well as new Web platforms and privacy systems. Discussion: NPSs represent an unprecedented challenge in the field of public health with social, cultural, legal, and political implications.Web monitoring activities are essential for mapping the diffusion of NPSs and for supporting innovative Web-based prevention programmes.Peer reviewedSubmitted Versio
Upper limits for a narrow resonance in the reaction p + p -> K^+ + (Lambda p)
The reaction pp -> K^+ + (Lambda p) has been measured at T_p = 1.953 GeV and
\Theta = 0 deg with a high missing mass resolution in order to study the Lambda
p final state interaction. Narrow S = -1 resonances predicted by bag model
calculations are not visible in the missing mass spectrum. Small structures
observed in a previous experiment are not confirmed. Upper limits for the
production cross section of a narrow resonance are deduced for missing masses
between 2058 and 2105 MeV/c^2.Comment: 8 pages, 5 figure
26 Weryfikacja obliczeń dawek wykonywanych za pomocą systemu CadPlan
Radioterapia jest procesem złożonym obejmującym szereg krokó proceduralnych. Dokładność każdego z nich wpływa bezpośrednio na wynik leczenia. Niedokładności lub błędy podczas komputerowego planowania leczenia mogą zmniejszyć odsetek wyleczeń lub nawet spowodować poważne komplikacje u napromienianych pacjentów. Zalecenie niezależnego obliczania dawki przynajmniej w jednym punkcie planu, np. w izocentrum lub w punkcie położonym blisko środka guza, nabiera szczególnego znaczenia zwłaszcza w okresie wdrażania do praktyki klinicznej nowego komputerowego systemu do planowania leczenia.CelOpracowanie procedury kontroli jakości obliczeń dawek wykonywanych za pomocą systemuCadPlan.Materiał i metodyJednym z elementów linii terapeutycznej firmy Varian zainstalowanej w Centrum Onkologii w Krakowie jest komputerowy system planowania leczenia CadPlan współpracujący z tomografem komputerowym GE Sytec 3000i i połączony po poprzez system zarządzania i weryfikacji VARiS z akceleratorem liniowym CLlNAC 600C. Pomiary dozymetryczne akceleratora CLlNAC 600C wytwarzającego wiązkę fotonową o energii 6 MV wykonano w zakresie pokrywającym wymagania zarówno systemu CadPlan jak i opracowanych wcześniej w naszym Zakładzie Fizyki Medycznej i uruchomionych na minikomputerze typu IBM PC programów APARAT i PLAN. Program APARAT dla zadanych parametrów wiązek promieniowania fotonowego podaje aktualne wydajności aparatu terapeutycznego i procentowe dawki głębokościowe, a po wprowadzeniu frakcyjnej dawki wlotowej określa czas ekspozycji albo liczbę jednostek monitorowych odpowiednio dla napromieniania na aparacie kobaltowym lub akceleratorze. Program PLAN umożliwia realizację planowania leczenia 2D wiązkami fotonowymi z uwzględnieniem niejednorodności obszaru napromienianego.Wyniki obliczeń systemu CadPlan, zamieszczone na wydrukach, są weryfikowane za pomocą programu APARAT. W przypadku występowania niejednokrotności (np. płuca) poprawność obliczonych dawek sprawdzana jest przy użyciu programu PLAN, do którego dane topometryczne wprowadzone są wprost z wydrukowanego przez CadPlan przekroju poprzecznego pacjenta w płaszczyźnie centralnej wiązki.Wyniki i wnioskiOpracowany sposób kontroli poprawności obliczeń dawek wykonywanych za pomocą systemu CadPlan oparty jest na wieloletnim doświadczeniu w użytkowaniu programów komputerowych APARAT i PLAN. Zastosowana metoda pozwala na stosunkowo szybkie sprawdzenie obliczonych za pomocą systemu CadPlan wartości dawek w wybranych punktach na osiach wiązek. Procedura jest łatwa w użyciu i przejrzysta, a jej rutynowe stosowanie przyczynia się do zapewnienia bezpieczeństwa napromienianych pacjentów
Detailed comparison of the pp -> \pi^+pn and pp -> \pi^+d reactions at 951 MeV
The positively charged pions produced in proton-proton collisions at a beam
momentum of 1640 MeV/c were measured in the forward direction with a high
resolution magnetic spectrograph. The missing mass distribution shows the bound
state (deuteron) clearly separated from the continuum. Despite the very
good resolution, there is no evidence for any significant production of the
system in the spin-singlet state. However, the cross section ratio is about twice as large as
that predicted from -wave final-state-interaction theory and it is suggested
that this is due to -state effects in the system.Comment: 8 pages, 3 figure
Optimal duration and combination of antiplatelet therapies following percutaneous coronary intervention: a meta-analysis.
Abstract Introduction The ideal duration of dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) is still unknown. In this meta-analysis, we aimed to compare very short-term (1–3 months), short-term (6 months), standard-term (12 months) and long-term (>12 months) DAPT durations for efficacy and safety. Methods Overall DAPT comparisons were classified as "any shorter-term"/"any longer-term" DAPT. The primary outcome was a composite of major adverse cardiovascular events (MACE: non-fatal myocardial infarction, non-fatal stroke and cardiovascular death). The primary safety outcome was major bleeding. Results Twenty-six studies comprising 103.394 patients were included. Compared with standard-term DAPT duration, very short-term DAPT duration with subsequent drop of aspirin (RR 1.06, 95% CI, 0.95–1.18, p = 0.26) or drop of the P2Y12 inhibitor (RR 0.92, 95% CI, 0.72-1.16, p = 0.47) was not associated with a higher risk of MACE. Any longer-term compared with any shorter-term DAPT durations led to a significantly lower risk of MACE (RR 0.88, 95% CI, 0.81–0.96, p = 0.002), but a significantly higher risk of BARC 3-5 major bleeding events (RR 1.63, 95% CI, 1.22–2.17, p = 0.001). In the ACS subgroup receiving prasugrel or ticagrelor but not clopidogrel, any longer-term DAPT duration was associated with a significantly lower risk of MACE compared to any shorter-term DAPT duration (RR 0.84, 95% CI, 0.77–0.92, p = 0.0001). Conclusion DAPT may be shortened to 1-3 months in patients with low ischemic but high bleeding risk followed by aspirin or P2Y12 monotherapy. Prasugrel or ticagrelor based DAPT may be extended to >12 months in case of high ischemic and low bleeding risk. PROSPERO registration no CRD42020163719
- …