Server Placement with Shared Backups for Disaster-Resilient Clouds

A key strategy to build disaster-resilient clouds is to employ backups of virtual machines in a geo-distributed infrastructure. Today, the continuous and acknowledged replication of virtual machines in different servers is a service provided by different hypervisors. This strategy guarantees that the virtual machines will have no loss of disk and memory content if a disaster occurs, at a cost of strict bandwidth and latency requirements. Considering this kind of service, in this work, we propose an optimization problem to place servers in a wide area network. The goal is to guarantee that backup machines do not fail at the same time as their primary counterparts. In addition, by using virtualization, we also aim to reduce the amount of backup servers required. The optimal results, achieved in real topologies, reduce the number of backup servers by at least 40%. Moreover, this work highlights several characteristics of the backup service according to the employed network, such as the fulfillment of latency requirements.Comment: Computer Networks 201

The infrared imaging spectrograph (IRIS) for TMT: design of image slicer

The InfraRed Imaging Spectrograph (IRIS) is one of three first light science instruments for the Thirty Meter Telescope (TMT). It will provide dedicated function of imaging and integral field spectroscopic observations in parallel with the assistance of a Narrow Field InfraRed Adaptive Optics System (NFIRAOS). The IRIS imager delivers celestial light to a dual-channel Integral Field Spectrograph (IFS) through a pair of pick-off mirrors in the central field. The IFS creates multi-functional ability to explore the universe in IR (0.84 – 2.4um) with moderate spectral resolution of R=4,000/8,000 and four spaxel scales of 4, 9, 25, 50 milli-arc-seconds (mas). An image slicer serves one of the two spectral channels as its Integral Field Unit (IFU) in two coarse spaxel scales of 25 and 50mas over the continuous science fields of 2.2x1.125 arc-seconds (arcsec) and 4.4x2.25 arcsec respectively. It splits the field to 88 unit systems, and then re-images at two parallel slits in order to take full advantage of the detector (4Kx4K @ 15um). This paper describes a novel all-reflective design of image slicer, which uses a new ‘brick stage’ layout to stagger the adjacent mirrors and deliver image quality close to diffraction limit. The quasi-telecentric optical design gives more friendly interfaces with pre-optics and spectrograph than the conceptual design. Here, more technical issues are discussed to guide the further study on optical performance and fabrication feasibility

Modular synthesis of simple cycloruthenated complexes with state-of-the-art performance in p-type DSCs

A modular approach based on Suzuki-Miyaura cross coupling and Miyaura borylation has been used to prepare two cyclometallated [Ru(N^N) 2 (C^N)] + complexes which possess either a carboxylic or phosphonic acid group attached via a phenylene spacer to the 4-position of the pyridine ring in the C^N ligand. The key intermediate in the synthetic pathway is [Ru(bpy) 2 ( 1 )] + where bpy = 2,2'-bipyridine and H 1 is 4-chloro-2-phenylpyridine. The crystal structure of [Ru(bpy) 2 ( 1 )][PF 6 ] is presented. Reaction of [Ru(bpy) 2 ( 1 )][PF 6 ] with 4-carboxyphenylboronic acid leads to [Ru(bpy) 2 (H 6 )][PF 6 ], while the phosphonic acid analogue is isolated as the zwitterion [Ru(bpy) 2 (H 5 )]. The cyclometallated complexes have been characterized by mass spectrometry, multinuclear NMR spectroscopy, absorption spectroscopy and electrochemistry. [Ru(bpy) 2 ( 5 )] adsorbs onto NiO FTO/NiO electrodes (confirmed by solid-state absorption spectroscopy) and its performance in p-type dye-sensitized solar cells (DSCs) has been compared to that of the standard dye P1; two-screen printed layers of NiO give better DSC performances than one layer. Duplicate DSCs containing [Ru(bpy) 2 (H 5 )] achieve short-circuit current densities ( J SC ) of 3.38 and 3.34 mA cm –2 and photoconversion efficiencies ( η ) of 0.116 and 0.109%, respectively, compared to values of J SC = 1.84 and 1.96 mA cm –2 and η = 0.057 and 0.051% for P1. Despite its simple dye structure, the performance of [Ru(bpy) 2 (H 5 )] parallels the best-performing cyclometallated ruthenium(II) dye in p-type DSCs reported previously (He et al , J. Phys. Chem. C , 2014, 118 , 16518) and confirms the effectiveness of a phosphonic acid anchor in the dye and the attachment of the anchoring unit to the pyridine (rather than phenyl) ring of the cyclometallating ligan

Równość czy efektywność. Wpływ polityki spójności na procesy wzrostu gospodarczego w województwach

In recent years, the issue of investment projects has been addressed in the context of discussions on the principles of regional policy and economic convergence, which remain important objectives of cohesion policy implemented and co-financed within the framework of the European Union. This study on the effects of investment projects carried out in provinces as part of cohesion policy uses economic growth models as methodological tools. As a result of the study, the longterm effects of cohesion policy implemented in Poland under the EU’s 2014–2020 Financial Perspective were determined. The obtained results did not confirm the achievement of the goal of equalising GDP levels per working person between the provinces in the long term. The article demonstrates how mathematical models of economic growth can be used in the process of allocating investment projects between provinces. According to the indications of the models, this process will contribute to the achievement of the goal, considering both the polarisation-diffusion paradigm and the compensatory paradigm of regional policy. The study successfully incorporates the mathematical theory of economic growth into the ongoing discussion on the methods and effects of pursuing regional policy

Jarosław Marek Rymkiewicz a przemijanie – interpretacja wiersza Ćma

Artykuł zawiera interpretację utworu pt. Ćma współczesnego polskiego poety – Jarosława Marka Rymkiewicza. W wierszu realizowane są dwa motywy, które ludzkość zna od początku refleksji nad światem – śmierć i przemijanie. Ponadto praca wykazuje wielość możliwych inspiracji autora liryku – od antyku (mity grecko-rzymskie), przez średniowiecze (danse macabre), po barok (fragment opery Rinaldo Georga Friedricha Händla w motcie analizowanego tekstu, twórczość Daniela Naborowskiego). Rymkiewicz odwołuje się takżedo symboliki poszczególnych elementów wykreowanego świata (realistycznie opisane zachowanie oraz wygląd ćmy czy skąpane w deszczu oleandry. Co więcej, wieloaspektowość i tematyka wiersza (śmierć czeka każdego człowieka) pozostają w sprzeczności z wizerunkiem poety jako twórcy tekstów wyłącznie o wyraźnie stronniczym, politycznym charakterze

LED-wpływ na jakość widzenia i zagrożenia z nimi związane.

W dzisiejszych czasach oświetlenie w naszych domach, ulicach, biurach oraz galeriach handlowych stopniowo przekształcało się z konwencjonalnych żarówek do żarówek energooszczędnych, świetlówek, a obecnie rynek oświetleniowy zdominowały lampy LED. Wiąże się z tym dużo korzyści, takich jak lepsza skuteczność świetlna oraz oszczędność energii, która obecnie odgrywa ważną rolę w życiu każdego człowieka. Jednak należy zastanowić się, czy źródła LED, są źródłami idealnymi. W artykule omówione zostaną problemy związane z promieniowaniem jakie wydzielają LED-y oraz problemy z interpretacją współczynnika oddawania barw. Przeprowadzona zostanie analiza korzyści, wad i zagrożeń współczesnego oświetlenia

Risk Factors in a Process of Gas Supply Pipeline Construcion

The paper applies to the risk management in the specialized construction by the example of construction of a high-pressure gas supply pipeline. The specific character of the construction project has an impact on the scope and types of risks which may occur and adversely affect the outcome of the project. The paper aims to indicate the groups of technological tasks which need to be carried out when constructing a gas supply pipeline, the associated factor risks and the quality control method as a tool of mitigating the level of risk

Cukrzyca u chorego po przeszczepieniu nerki — spojrzenie nefrodiabetologiczne

A transplant physician often has under his care a kid­ney recipient with end-stage kidney disease due to diabetes mellitus (DM) or DM developed after trans­plantation (posttransplantation diabetes mellitus — PTDM). The presence of DM is associated with a de­terioration in quality of life and worse prognosis both for the transplanted kidney and the patient survival. Such patients should be provided with combined and coordinated nephrology/diabetes care. The diagnostic procedures for PTDM do not differ from those gen­erally accepted, the basic one being an oral glucose load test. An important role in the control of treatment is played by glycated haemoglobin, sometimes used as a diagnostic support tool. Until now, no unambigu­ous standards of therapeutic treatment in PTDM have been established and both in the diagnosis and the therapeutic regimens apply the guidelines established for diabetic patients without a transplanted organ. The basis of treatment should be a diet combined with ap­propriate physical exercise. There are many hypogly­cemic medications available, including new ones with wide spectrum pharmacokinetic and pharmacody­namic properties that vary in efficacy and safety pro­file. Graft function and also possible interactions with other medications, especially immunosuppressants, should be taken into account before implementing hy­poglycemic treatment in transplanted patients

What makes medical students choose their residencies? Association between mental health of medical students and their choices of future medical specialties

Background: Excessive cognitive demands and chronic stress contribute to the occurrence of mental health problems among medical students. It may be hypothesized that the presence of such disturbances have an influence on their choices of post-graduate training programs. Objective: The aim of the study was to evaluate the state of mental health of medical students and to assess if there is any association between the prevalence of mental health problems and their residency choices. Materials and methods: 114 medical students were surveyed in terms of their residencies' choices and their mental health with the usage of validated psychological questionnaires. Results: 74 (64,91%) of medical students needed psychiatric or psychological treatment at some stage in their lives. Intensity of risky alcohol consumption was positively correlated with the choice of surgery (p=.0000) and negatively correlated with the choice of psychiatry (p=.0000). The severity of depressive symptoms was positively correlated with emergency medicine choice (p=.0479). Anxiety symptoms, eating disorders and autism spectrum severity symptoms were not significantly correlated with the choice of any medical specialty. Conclusions: Medical students were found seriously affected by mental health problems, what to some extent seemed to impact their future career choices

Zbyt intensywne leczenie chorych na cukrzycę typu 2 w podeszłym wieku

  Wstęp. U starszych pacjentów z cukrzycą typu 2 (T2DM) oraz poważnymi chorobami współistniejącymi ryzyko wynikające ze ścisłej kontroli glikemii przewyższa jej korzyści. Cele niniejszej pracy obejmowały ocenę od­setka hemoglobiny glikowanej A1c (HbA1c) u chorych na T2DM ≥ 80. roku życia oraz porównanie odsetka HbA1c u chorych hospitalizowanych z powodu ciężkiej hipoglikemii (SH) i innych przyczyn internistycznych. Materiał i metody. Do badania włączono 166 chorych na T2DM powyżej 80. roku życia, hospitalizowanych w latach 2009–2013 z różnych przyczyn internistycznych. Wyniki. Średni wiek pacjentów wynosił 83,72 ± 3,19 roku, średni czas trwania cukrzycy 9,14 ± 5,88 roku, średni wskaźnik masy ciała (BMI) 27,87 ± 4,51 kg/m2 i średni współczynnik filtracji kłębuszkowej (GFR) 58,94 ± 25,87 ml/min/1,73 m². Średnia wartość HbA1c dla całej grupy wynosiła 7,61 ± 1,87% (59,77 ± 20,48 mmol/mol). Ścisłą kontrolę glikemii z HbA1c < 7,0% (53 mmol/mol) odnotowano u 77 chorych (46%). Ciężką hipoglikemię rozpoznano u 19 (11%) pacjentów. Chorzy z SH cechowali się istotnie niż­szym średnim odsetkiem HbA1c niż pacjenci hospi­talizowani z innych przyczyn (6,38 ± 1,22 vs. 7,77 ± 1,88% (46,31 ± 13,36 vs. 61,51 ± 20,63 mmol/mol); p = 0,002). Częstość występowania zawału serca i/lub udaru mózgu była prawie dwukrotnie wyższa u chorych na cukrzycę hospitalizowanych z powodu SH niż u pacjentów bez hipoglikemii (47 vs. 28%; c² = 3,03; p = 0,082). Ciężką hipoglikemię stwierdzono tylko u pacjentów otrzymujących insulinę (n = 10) lub pochodną sulfonylomocznika (SU) (n = 9). Wnioski. Mimo że u chorych na T2DM w starszym wieku ryzyko wynikające z intensywnego leczenia hi­poglikemizującego przewyższa jego korzyści, połowa badanych cechowała się ścisłą kontrolą glikemii. Co dziesiąty pacjent był hospitalizowany z powodu SH. U osób z SH odnotowano istotnie niższy średni odsetek HbA1c niż u osób hospitalizowanych z innych przyczyn. Ob­serwacje autorów sugerują, że znaczna część pacjentów z T2DM w wieku ≥ 80 lat może być leczona zbyt intensywnie