117 research outputs found

    Thick brane solutions and topology change transition on black hole backgrounds

    Full text link
    We consider static, axisymmetric, thick brane solutions on higher dimensional, spherically symmetric black hole backgrounds. It was found recently [1], that in cases when the thick brane has more than 2 spacelike dimensions, perturbative approaches break down around the corresponding thin solutions for Minkowski type topologies. This behavior is a consequence of the fact that thin solutions are not smooth at the axis, and for a general discussion of possible phase transitions in the system, one needs to use a non-perturbative approach. In the present paper we provide an exact, numerical solution of the problem both for black hole- and Minkowski type topologies with arbitrary number of brane and bulk dimensions. We also illustrate a topology change transition in the system for a 5-dimensional brane embedded in a 6-dimensional bulk.Comment: 11 pages, 10 figures, accepted for publication in Phys. Rev.

    Awareness about the Relevance of Cascading Effects in Urban Critical Infrastructure Networks under Climate Change – a Participatory Impact Matrix Approach

    Get PDF
    Addressing climate change adaptation in urban areas is increasingly urgent. To achieve sustainable and climate-adapted fields of action requires fundamental transformations of supply chains and infrastructures such as transport and mobility, electricity and water supply, or telecommunication as well as an improved understanding of their interactions. Practical experiences show, that in general there is an increasing awareness about this, but for example emergency plans or crisis communication often falls short regarding the indirect impacts of climate change on potential infrastructural failures. Hence, there is also a growing need for applied research and systemic approaches to overcome the current prevailing isolated sectoral view of climate change impacts to gain a holistic understanding of the critical infrastructure networks. Against this background, the paper highlights the relevance of climate change impacts on critical infrastructures, infrastructure interdependencies and potential systemic cascading effects. The analysis uses a participatory approach that has been applied within a case-study for the metropolitan area of Hamburg, Germany. It is based on transdisciplinary research methods, connecting the realms of scientific knowledge about regional climate change with real-world experiences. A strong focus lies on the use of a specific impact matrix approach carried out with key stakeholders from different sectors to identify climate-related drivers causing the most severe failures and losses in the system – either directly in the same sector or indirectly due to breakdowns in other sectors. In sum, the case-study enables a first categorization of the role single key variables play in the infrastructure system. Furthermore, it introduces the topic of adaptation to climate change as a starting point for a better understanding and management of systemic risks in order to build and maintain resilient critical infrastructures and to make urban areas safe, resilient and sustainable

    Spectroscopic Study of the Excitonic Structure in Monolayer MoS2 under Multivariate Physical and Chemical Stimuli

    Get PDF
    Photoluminescence (PL) spectroscopy has proven to provide deep insights into the optoelectronic properties of monolayer MoS2. Herein, a corresponding study is conducted on the excitonic properties of mechanically exfoliated monolayer MoS2 under multivariate physical and chemical stimuli. Specifically, midgap exciton states that originate from lattice defects are characterized and they are compared to existing models. Through statistical data analyses of substrate-, temperature-, and laser-power-dependent measurements, a PL enhancement is revealed through physisorption of water molecules of the controversially discussed excited-state A biexciton (Axx). In addition, analyses of monolayer MoS2 on gold substrates show that surface roughness does not account for changes in doping level within the material. Also, a shift in the electron–phonon coupling properties that arises from thin films of water that are physisorbed on top of the samples is reported.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe

    Visoka učestalost neliječene i nedovoljno liječene deficijencije i insuficijencije vitamina D u bolesnika s upalnim bolestima crijeva

    Get PDF
    Inflammatory bowel disease (IBD) patients with vitamin D deficiency show an increased risk of hospital admission, surgery, and loss of response to biologic therapy while high vitamin D levels are identified as a protective factor. Our goal was to investigate the prevalence of untreated and undertreated vitamin D deficiency and factors associated with vitamin D deficiency. In this cross-sectional study, we measured serum vitamin D in a random sample of Caucasian IBD patients. Vitamin D deficiency was defined as <50 nmol/L and insufficiency as 50-75 nmol/L. Supplementation was defined as taking 800-2000 IU vitamin D daily. Untreated patients were defined as not taking supplementation and undertreated group as receiving supplementation but showing vitamin D deficiency or insufficiency despite treatment. Our study included 185 IBD patients, i.e. 126 (68.1%) with Crohn’s disease (CD) and 59 (31.9%) with ulcerative colitis (UC). Overall, 108 (58.4%) patients had vitamin D deficiency and 60 (32.4%) patients vitamin D insufficiency. There were 16 (14.8%) and 11 (18.3%) treated patients in vitamin D deficiency and vitamin D insufficiency group, respectively. The rate of untreated patients was 81.7% (n=49) in vitamin D deficiency group and 85.2% (n=92) in vitamin D insufficiency group. Tumor necrosis factor alpha inhibitors were associated with higher serum vitamin D levels in CD and UC, and ileal involvement, ileal and ileocolonic resection with lower levels. In conclusion, not only is vitamin D deficiency common in IBD patients but the proportion of untreated and undertreated patients is considerably high. We suggest regular monitoring of vitamin D levels in IBD patients regardless of receiving vitamin D supplementation therapy.Bolesnici s upalnim bolestima crijeva (inflammatory bowel disease, IBD) i manjkom vitamina D su pod povećanim rizikom hospitalizacije, operacije i gubitka odgovora na bioloĆĄku terapiju, dok visoke serumske razine vitamina D predstavljaju zaĆĄtitni čimbenik. Cilj ove studije bio je istraĆŸiti učestalost neliječenih i nedovoljno liječenih bolesnika s IBD i manjkom vitamina D te čimbenike rizika. U ovoj presječnoj studiji mjerene su serumske razine vitamina D u slučajnom uzorku bolesnika s IBD bijele rase. Deficijencija je definirana kao razine <50 nmol/L, a insuficijencija kao 50-75 nmol/L. Nadoknada vitamina D je definirana kao uzimanje 800-2000 IJ vitamina D na dan. Neliječeni bolesnici su oni bez nadoknade, a nedovoljno liječeni oni s deficijencijom ili insuficijencijom usprkos nadoknadi. Uključeno je ukupno 185 bolesnika s IBD, tj. 126 (68,1%) s Crohnovom boleơću i 59 (31,9%) s ulceroznim kolitisom. Ukupno je 108 (58,4%) bolesnika imalo deficijenciju, a 60 (32,4%) insuficijenciju. Udio liječenih bolesnika s deficijencijom i insuficijencijom vitamina D iznosio je 14,8% (n=16) i 18,3% (n=11). Udio neliječenih s deficijencijom iznosio je 81,7% (n=49), a s insuficijencijom 85,2% (n=92). Terapija inhibitorima faktora tumorske nekroze alfa bila je povezana s viĆĄim razinama vitamina D. NiĆŸe razine vitamina D su zabiljeĆŸene kod bolesnika s upalom u području ileuma i resekcijom ileuma ili ileokolona. U zaključku, niske serumske razine vitamina D su česta pojava kod bolesnika s IBD, a dodatno je udio neliječenih i nedovoljno liječenih također visok. NaĆĄa preporuka je kontinuirano praćenje razina vitamina D u serumu svih bolesnika s IBD uključujući i one na nadoknadi vitaminom D

    Stanje uhranjenosti i kvaliteta prehrane u bolesnika s nealkoholnom boleơću masne jetre

    Get PDF
    Non-alcoholic fatty liver disease (NAFLD) is becoming a major health burden with increasing prevalence worldwide due to its close association with the epidemic of obesity. Currently there is no standardized pharmacological treatment, and the only proven effective therapeutic strategy is lifestyle modification, therefore it is important to determine the potential dietary targets for the prevention and treatment of NAFLD. We assessed nutritional status in 30 patients diagnosed with NAFLD using anthropometric parameters, hand grip strength, and lifestyle and dietetic parameters (physical activity, NRS2002 form and three-day food diary). The mean body mass index was 29.62±4.61 kg/m2, yielding 86.67% of obese or overweight patients. Physical activity results indicat-ed poorly active subjects. Excessive energy intake was recorded in 27.78% of patients. The mean in-take of macronutrients was as follows: 15.5% of proteins, 42.3% of carbohydrates and 42.2% of fat, with ­deficient micronutrient intake of calcium, magnesium, iron, zinc, and vitamins A, B1 and B2. The ­results showed that the quality of nutrition in study subjects was not accordant to current rec-ommendations and that they consumed a high proportion of fat, especially saturated fatty acids, along with low micronutrient intake. The results obtained might point to the importance of unbalanced diet as a contributing factor in NAFLD development.Nealkoholna bolest masne jetre (NAFLD) postaje velik zdravstveni problem s povećanom učestalosti u svijetu zbog bliske povezanosti s epidemijom pretilosti. Kako zasad ne postoji standardizirano farmakoloĆĄko liječenje i jedina dokazana učinkovita terapijska strategija je promjena načina ĆŸivota, vaĆŸno je odrediti potencijalne prehrambne ciljeve za prevenciju i liječenje NAFLD. Procijenili smo nutritivni status 30 bolesnika s dijagnosticiranim NAFLD primjenom antropometrijskih parametara, mjerenjem snage ruke dinamometrom i dijetetskim parametrima (tjelesna aktivnost, upitnik NRS 2002 i tro­dnevni dnevnik prehrane). Srednja vrijednost indeksa tjelesne mase bila je 29,62±4,61 kg/m2 s 86,67% bolesnika koji su bili prekomjerne tjelesne mase ili pretili. Rezultati tjelesne aktivnosti pokazuju da su ispitanici bili slabo aktivni. Prekomjerni energetski unos u odnosu na dnevne potrebe imalo je 27,78% bolesnika. Prosječan dnevni unos makronutrijenata je iznosio: 15,5% proteina, 42,3% ugljikohidrata i 42,2% masti s nedostatnim unosom sljedećih mikronutrijenata: kalcij, magnezij, Â­ĆŸeljezo, cink, vitamini A, B1 i B2. Rezultati istraĆŸivanja pokazuju da kvaliteta prehrane naĆĄih ispitanika nije bila u skladu s aktualnim preporukama i da su konzumirali velike količine masti, pogotovo zasićenih masnih kiselina s niskim unosom ­mikronutrijenata. Dobiveni rezulatati bi mogli ukazati na ulogu nepravilne prehrane kao vaĆŸnog čimbenika razvoja NAFLD-a

    Nutritivni problemi i nutritivna potpora u bolesnika starije dobi na kućnoj njezi u gradu Zagrebu

    Get PDF
    Population aging is a global demographic trend showing continuous growth and among its consequences is a rise in malnutrition that is characteristic for the elderly. The objective of this study was to evaluate nutritional status of elderly home care patients immediately after hospital discharge and to determine factors that affect nutritional status using questionnaires based on validated tools (NRS-2002, DETERMINE checklist) and basic medical history data. The study involved 76 elderly individuals (51.3% of them older than 70) living in the City of Zagreb. The nutritional status assessment using the NRS-2002 tool showed that 57.6% of the subjects were at nutritional risk. The findings of the assessment by use of the DETERMINE tool were also unfavorable, indicating that 82.1% of persons older than 70 were categorized as being at a high nutritional risk, while 17.9% were at moderate risk. The DETERMINE checklist elements (illness; reduced intake of fruits, vegetables or dairy products; alcohol consumption; oral health problems; and weight loss) were linked to a higher NRS score. The mean number of hospital days in subjects at nutritional risk was 14.27 (the mean number in the Republic of Croatia is 8.56 days). Although the study involved a small number of subjects, the results showed a substantial presence of malnutrition among the elderly. A timely ­intervention by the healthcare system and training of healthcare personnel can be a step towards achieving a better nutritional status.Starenje stanovniĆĄtva je globalni demografski trend u stalnom porastu, a time je u porastu i malnutricija karakteristična za osobe starije ĆŸivotne dobi. Cilj ovoga rada bio je procijeniti nutritivni status osoba starije ĆŸivotne dobi na kućnoj njezi neposredno nakon otpusta iz bolnice te utvrditi čimbenike koji utječu na nutritivni status. KoriĆĄten je upitnik sastavljen na temelju validiranih instrumenata (NRS-2002, upitnik DETERMINE) i osnovnih anamnestičkih podataka. IstraĆŸivanjem je obuhvaćeno 76 osoba starije ĆŸivotne dobi (51,3% stariji od 70 godina) na području grada Zagreba. Procjenom nutritivnog statusa upitnikom NRS-2002 u 57,6% ispitanika utvrđen je nutritivni rizik. Rezultati utvrđeni procjenom pomoću upitnika DETERMINE također su bili nepovoljni: 82,1% osoba starijih od 70 godina imalo je visok nutritivni rizik, dok ih je 17,9% imalo umjeren rizik. Elementi upitnika DETERMINE (prisutnost bolesti, smanjen unos voća, povrća ili mliječnih proizvoda, konzumacija alkoholnih pića, problemi s oralnim zdravljem i gubitak tjelesne mase) povezani su s viĆĄim rezultatom NRS. Prosječan broj dana hospitalizacije u ispitanika s nutritivnim rizikom bio je 14,27 dana (prosjek u Republici Hrvatskoj je 8,56 dana). Iako je istraĆŸivanjem obuhvaćen mali broj ispitanika, već i ovakvi rezultati ukazuju na to da je problem mal-nutricije u velikoj mjeri prisutan među osobama starije ĆŸivotne dobi. Pravodobna intervencija sustava zdravstvene zaĆĄtite i izobrazba zdravstvenog osoblja moĆŸe biti korak prema postizanju boljeg nutritivnog statusa

    First-Year Spectroscopy for the SDSS-II Supernova Survey

    Get PDF
    This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.Comment: Accepted for publication in The Astronomical Journal(47pages, 9 figures

    The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V

    Get PDF
    The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Comment: Accepted to ApJ

    The eighteenth data release of the Sloan Digital Sky Surveys : targeting and first spectra from SDSS-V

    Get PDF
    The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Publisher PDFPeer reviewe

    Sloan Digital Sky Survey IV: mapping the Milky Way, nearby galaxies, and the distant universe

    Get PDF
    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median ). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July
    • 

    corecore