Atrial Fibrillation in Cancer Patients: Who is at Risk?

Cancer is the second leading cause of mortality in the world, second only to cardiovascular diseases. Simultaneously cancer mortality has been steadily decreasing due to the development of new chemotherapy and targeted drugs and the improvement of existing treatment protocols. Improving the prognosis of treatment of cancer patients leads to an unexpected result - more patients are faced with side effects of cancer treatment. Cardiotoxicity, including arrhythmia, has become a significant factor to reduce the effectiveness of cancer patient’s treatment. Atrial fibrillation is frequent and persistent a rhythm disorder, affecting all categories of patients, especially the elderly. An association between these two conditions can be expected, considering the fact that in old age the prevalence of malignant neoplasms and comorbid pathology predisposing to the onset of AF is high. Therefore, AF may be an additional factor negatively influencing the prognosis and treatment tactics in patients with malignant neoplasms. A comprehensive search was conducted using the keywords “cancer”, “atrial fibrillation” and “cardiotoxicity” using the PubMed, Scopus and Cohrane databases. We reviewed publications having the relationship between AF and cancer. The literature review considered 61 publications on the prevalence of AF in cancer patients, classification, mechanisms of development, the effect of anticancer drugs and other treatment methods on this group of patients. Analyzed articles include clinical guidelines, consensus expert opinions, systematic reviews, meta-analyzes, and previously published reviews of the literature. The problem of cardiotoxic complications diagnostics is evaluated separately, incl. arrhythmias, and their monitoring in cancer patients. Therefore, the direction of medicine named "Cardio-oncology" comes to the fore. Interdisciplinary interaction will allow identify cardiotoxic manifestations at the subclinical stage and optimize anticancer treatment.

A Bayesian Hierarchical Spatio-Temporal Model for Extreme Temperatures in Extremadura (Spain) Simulated by a Regional Climate Model

A statistical study was made of the temporal trend in extreme temperatures in the region of Extremadura (Spain) during the period 1981-2015 using a Regional Climate Model. For this purpose, a dataset of extreme temperature was obtained from the Weather Research and Forecating (WRF) Regional Climate Model. This dataset was then subjected to a statistical study using a Bayesian hierarchical spatio-temporal model with a Generalized Extreme Value (GEV) parametrization of the extreme data. The Bayesian model was implemented in a Markov chain Monte Carlo framework that allows the posterior distribution of the parameters that intervene in the model to be estimated. The role of the altitude dependence of the temperature was considered in the proposed model. The results for the spatial-trend parameter lend confidence to the model since they are consistent with the dry adiabatic gradient. Furthermore, the statistical model showed a slight negative trend for the location parameter. This unexpected result may be due to the internal and modeling uncertainties in the WRF model. The shape parameter was negative, meaning that there is an upper bound for extreme temperatures in the model.

Racial Disparities in Mortality During the 1918 Influenza Pandemic in United States Cities

The 1918 influenza pandemic stands out because of the unusual age pattern of high mortality. In the United States, another feature merits scientific scrutiny: against a historical backdrop of extreme racial health inequality, the pandemic produced strikingly small ratios of nonwhite to white influenza and pneumonia mortality. We provide the most complete account to date of these racial disparities in 1918, showing that, across U.S. cities, they were almost uniformly small. We examine four potential explanations for this unexpected result, including [1] socio-demographic factors like segregation, [2] city-level implementation of non-pharmaceutical interventions (NPIs), [3] exposure to the milder spring 1918 “herald wave,” and [4] early-life exposures to other influenza strains resulting in differential immunological vulnerability to the 1918 flu. While we find little evidence for 1-3, we offer suggestive evidence that racial variation in early-life exposure to the 1889-1892 influenza pandemic shrunk racial disparities during the 1918 pandemic. We also raise the possibility that differential behavioral responses to the herald wave may have protected nonwhite urban populations. By providing a comprehensive description and careful examination of the potential drivers of racial inequality in mortality during the 1918 pandemic, our study provides a framework to consider interactions between the natural history of particular microbial agents and the social histories of the populations they infect.

The Role of Internationalization Orientation in Mediating the Relationship between Capabilities and Intention to Export: An Empirical Analysis on SMEs

Small and Medium Enterprises (SMEs) have a strategic role in the Indonesia's economy; however, they have a low contribution on the national export. Studying on SMEs internationalization becomes important to understand factors that influence them to go international. Using resource-based view perspective, the objective of study is to investigate how the organizational capabilities influence the intention of SMEs to export through internationalization orientation. A model was developed that explained the impact of personnel management, product development, and production capabilities on internationalization orientation, and eventually affect the export intention. Primary data were collected through a field survey by distributing structured questionnaires to SMEs over three months, resulting 86 eligible responses. These empirical data were analyzed to validate proposed model using partial least square - structural equation modeling technique (PLS-SEM). The results indicated that internationalization orientation mediated partially the effect of personnel management and product development capabilities on SMEs intention to export. The other finding displayed the unexpected result that there was insignificant influence of production capabilities on internationalization orientation and export intention. This study suggests that to increase the intention of SEMs to export, the firms must have capabilities in managing their personnel and developing unique and innovative product consistently.

CFD Analysis of the Influence of the Front Wing Setup on a Time Attack Sports Car’s Aerodynamics

In time attack races, aerodynamics plays a vital role in achieving short track times. These races are characterized by frequent braking and acceleration supported by aerodynamic downforce. Usually, typical cars are modified for these races by amateurs. Adjusting the aerodynamic solutions to work with bodies developed for other flow conditions is difficult. This paper presents the results of a numerical analysis of the effects of installing a straight wing in front of or above the body on the modified vehicle system’s aerodynamic characteristics, particularly on the front wheels’ aerodynamic downforce values. The paper presents the methodology and results of calculations of the aerodynamic characteristics of a car with an additional wing placed in various positions in relation to the body. The numerical results are presented (Cd, Cl, Cm, Clf, Clr), as well as exemplary pressure distributions, pathlines, and visualizations of vortex structures. Strong interactions between the wing operation and body streamline structure are shown. An interesting and unexpected result of the analysis is that the possibility of obtaining aerodynamic downforce of the front wheels is identified, without an increase in aerodynamic drag, by means of a wing placed in a proper position in front of the body. A successful attempt to balance the additional downforce coming from the front wing on the front axle is made using a larger spoiler. However, for large angles of attack, periodically unsteady flow is captured with frequency oscillations of ca. 6–12 Hz at a car speed of 40 m/s, which may interfere with the sports car’s natural suspension frequency.

Summertime productivity and carbon export potential in the Weddell Sea, with a focus on the waters adjacent to Larsen C Ice Shelf

The Weddell Sea represents a point of origin in the Southern Ocean where globally important water masses form. Biological activities in Weddell Sea surface waters thus affect large-scale ocean biogeochemistry. During January–February 2019, we measured net primary production (NPP), nitrogen (nitrate, ammonium, urea) uptake, and nitrification in the western Weddell Sea at the Antarctic Peninsula (AP) and Larsen C Ice Shelf (LCIS), in the southwestern Weddell Gyre (WG), and at Fimbul Ice Shelf (FIS) in the south-eastern Weddell Sea. The highest average rates of NPP and greatest nutrient drawdown occurred at LCIS. Here, the phytoplankton community was dominated by colonial Phaeocystis antarctica, with diatoms increasing in abundance later in the season as sea ice melted. At the other stations, NPP was variable, and diatoms known to enhance carbon export (e.g. Thalassiosira spp.) were dominant. Euphotic zone nitrification was always below detection, such that nitrate uptake could be used as a proxy for carbon export potential, which was highest in absolute terms at LCIS and the AP. Surprisingly, the highest f ratios occurred near FIS rather than LCIS (average of 0.73±0.09 versus 0.47±0.08). We attribute this unexpected result to partial ammonium inhibition of nitrate uptake at LCIS (where ammonium concentrations were 0.6±0.4 µM, versus 0.05±0.1 µM at FIS), with elevated ammonium resulting from increased heterotrophy following the accumulation of nitrate-fuelled phytoplankton biomass in early summer. Across the Weddell Sea, carbon export appears to be controlled by a combination of physical, chemical, and biological factors, with the highest potential export flux occurring at the ice shelves and lowest in the central WG.

The Light Responses of Proteorhodopsin-bearing, Antarctic Sea-ice Bacteria

<p>Although homogenous in appearance, Antarctic sea ice forms a complex habitat that is characterised by steep vertical gradients of temperature, irradiance and salinity. Despite these harsh and variable environmental conditions, numerous microbial organisms prosper within Antarctic sea ice. In 2010, bacteria bearing the proteorhodopsin (PR) gene were found within Antarctic sea ice. PR is a photoactive membrane protein that functions as a light-driven proton pump. The hydrogen ion membrane gradient that PR establishes has the potential to drive ATP synthesis, thus allowing PR-bearing bacteria to obtain energy from solar radiation. Although this gene is present in up to 80% of marine bacteria, the active contribution of PR in vivo is debatable. Light induced growth or enhanced survival is generally observed only when PR-bearing bacteria are grown under sub-optimum conditions, such as limited nutrients or carbon, or variations in salinity. This has lead to the general hypothesis that PR has multiple functions, becoming most influential under conditions of stress. In this way, Antarctic sea-ice bacteria may utilise PR to promote survival and enhance energy inputs, when exposed to the harsh conditions of this environment. To explore this hypothesis, potential PR-bearing isolates were cultured from samples of Antarctic sea-ice bacteria. Using 16S rRNA gene sequencing as well as a comparison of phenotypic and environmental characteristics, the isolates were identified as; Psychrobacter nivimaris, Polaribacter dokdonensis, Paracoccus marcusii and Micrococcus sp. These species, along with Psychroflexus torquis (an Antarctic sea-ice bacterium known to possess PR) were examined for the presence of the PR gene. This gene was identified in P. torquis, Ps. nivimaris and Po. dokdonensis. To my knowledge, this is the first time PR has been found in Ps. nivimaris. To assess the influence of irradiance on these species, a series of culture based experiments were undertaken. In 2012, a preliminary field experiment was conducted in which a mixed culture of PR-bearing and non PR-bearing bacteria; Ps. nivimaris, Po. dokdonensis, Pa. marcusii and Micrococcus sp., was incubated in situ in the annual sea ice surrounding Ross Island, Antarctica. The method developed for these experiments is unique, in that cultures of sea-ice bacteria have not before been incubated within their natural environment. No major differences in growth patterns were observed when bacteria were incubated under different wavelengths and light intensities, however, valuable insight into methodological improvement was obtained. Using these refinements, a second in situ incubation experiment was conducted at the same field site, in 2013. Over this 2 week incubation, monocultures of P. torquis grown in full strength media grew most readily under 50%- and blue-light treatments, with red- and green-light yielding lower biomasses, and no growth occurring in the dark. Ambient sea-ice irradiance resulted in highly variable growth, attributed to high irradiance growth-inhibition. These results indicate that P. torquis utilises low levels of light in order to increase its growth in Antarctic sea ice. The influence of light on the growth of P. torquis, Ps. nivimaris and Po. dokdonensis was examined in a laboratory-based experiment, in which media strength and temperature were varied. When cultured at 12°C, Ps. nivimaris grown under constant irradiance reached a higher biomass than in darkness. This trend was most pronounced when this species was cultured in a 10% media concentration. A trend of decreased exponential-growth was observed in light-incubated cultures of Ps. nivimaris, grown at 4°C or -1°C. Elevated maximum growth of Po. dokdonensis was observed under irradiated conditions in the 10% media treatment. This species however, only grew at 12°C; an unexpected result for an Antarctic microbe. P. torquis was not affected by irradiance under any culture conditions and did not grow at -1°C. This last result contrasts the results of the in situ incubations and may have been affected by factors such as culture age. This research demonstrates multiple examples of light-enhanced growth occurring in PR-bearing Antarctic sea-ice bacteria, with the most prominent trends occurring in reduced concentration media. Therefore, this work agrees with the overarching hypothesis that PR is most influential under conditions of stress. The varying effect of temperature on the influence of PR suggests that some species are able to use this protein at low temperatures, whilst others cannot. Therefore, PR likely provides a selective advantage to some species, depending on a variety of physicochemical factors, including nutrient and carbon availability, salinity and temperature.</p>

The Light Responses of Proteorhodopsin-bearing, Antarctic Sea-ice Bacteria

<p>Although homogenous in appearance, Antarctic sea ice forms a complex habitat that is characterised by steep vertical gradients of temperature, irradiance and salinity. Despite these harsh and variable environmental conditions, numerous microbial organisms prosper within Antarctic sea ice. In 2010, bacteria bearing the proteorhodopsin (PR) gene were found within Antarctic sea ice. PR is a photoactive membrane protein that functions as a light-driven proton pump. The hydrogen ion membrane gradient that PR establishes has the potential to drive ATP synthesis, thus allowing PR-bearing bacteria to obtain energy from solar radiation. Although this gene is present in up to 80% of marine bacteria, the active contribution of PR in vivo is debatable. Light induced growth or enhanced survival is generally observed only when PR-bearing bacteria are grown under sub-optimum conditions, such as limited nutrients or carbon, or variations in salinity. This has lead to the general hypothesis that PR has multiple functions, becoming most influential under conditions of stress. In this way, Antarctic sea-ice bacteria may utilise PR to promote survival and enhance energy inputs, when exposed to the harsh conditions of this environment. To explore this hypothesis, potential PR-bearing isolates were cultured from samples of Antarctic sea-ice bacteria. Using 16S rRNA gene sequencing as well as a comparison of phenotypic and environmental characteristics, the isolates were identified as; Psychrobacter nivimaris, Polaribacter dokdonensis, Paracoccus marcusii and Micrococcus sp. These species, along with Psychroflexus torquis (an Antarctic sea-ice bacterium known to possess PR) were examined for the presence of the PR gene. This gene was identified in P. torquis, Ps. nivimaris and Po. dokdonensis. To my knowledge, this is the first time PR has been found in Ps. nivimaris. To assess the influence of irradiance on these species, a series of culture based experiments were undertaken. In 2012, a preliminary field experiment was conducted in which a mixed culture of PR-bearing and non PR-bearing bacteria; Ps. nivimaris, Po. dokdonensis, Pa. marcusii and Micrococcus sp., was incubated in situ in the annual sea ice surrounding Ross Island, Antarctica. The method developed for these experiments is unique, in that cultures of sea-ice bacteria have not before been incubated within their natural environment. No major differences in growth patterns were observed when bacteria were incubated under different wavelengths and light intensities, however, valuable insight into methodological improvement was obtained. Using these refinements, a second in situ incubation experiment was conducted at the same field site, in 2013. Over this 2 week incubation, monocultures of P. torquis grown in full strength media grew most readily under 50%- and blue-light treatments, with red- and green-light yielding lower biomasses, and no growth occurring in the dark. Ambient sea-ice irradiance resulted in highly variable growth, attributed to high irradiance growth-inhibition. These results indicate that P. torquis utilises low levels of light in order to increase its growth in Antarctic sea ice. The influence of light on the growth of P. torquis, Ps. nivimaris and Po. dokdonensis was examined in a laboratory-based experiment, in which media strength and temperature were varied. When cultured at 12°C, Ps. nivimaris grown under constant irradiance reached a higher biomass than in darkness. This trend was most pronounced when this species was cultured in a 10% media concentration. A trend of decreased exponential-growth was observed in light-incubated cultures of Ps. nivimaris, grown at 4°C or -1°C. Elevated maximum growth of Po. dokdonensis was observed under irradiated conditions in the 10% media treatment. This species however, only grew at 12°C; an unexpected result for an Antarctic microbe. P. torquis was not affected by irradiance under any culture conditions and did not grow at -1°C. This last result contrasts the results of the in situ incubations and may have been affected by factors such as culture age. This research demonstrates multiple examples of light-enhanced growth occurring in PR-bearing Antarctic sea-ice bacteria, with the most prominent trends occurring in reduced concentration media. Therefore, this work agrees with the overarching hypothesis that PR is most influential under conditions of stress. The varying effect of temperature on the influence of PR suggests that some species are able to use this protein at low temperatures, whilst others cannot. Therefore, PR likely provides a selective advantage to some species, depending on a variety of physicochemical factors, including nutrient and carbon availability, salinity and temperature.</p>

Controls on Spatial and Temporal Variation in Snow Accumulation on Glaciers in the Southern Alps, New Zealand

<p>Mountain glaciers are already responding to climatic warming, and are expected to make a substantial contribution to sea-level rise in the coming decades. The aim of this investigation in the New Zealand Southern Alps was to improve our understanding of snow accumulation variability on mid-latitude maritime glaciers, in order to allow for better estimation of future glacier mass balance. The specific aim was to investigate snow accumulation processes at a range of spatial and temporal scales, focussing on synoptic-scale atmospheric circulation influences, moisture sources for snow accumulation and local-scale dependencies of snow accumulation in relation to topography. A range of methods were utilised including direct measurement, snow and ice core analysis, statistical analysis and modelling. Snow accumulation in the Southern Alps was found to be derived predominantly from the Tasman Sea, and deposited during low pressure troughs and fronts. Although precipitation increased with elevation, wind processes redistributed this mass. On a ~monthly timescale this redistribution caused an unexpected result, namely that wind deflation of snow on Franz Josef Glacier countered the effects of greater accumulation, and total accumulation was similar at both Franz Josef and Tasman Glaciers over this period. These processes make it challenging to simulate snow accumulation patterns by simply extrapolating snowfall over an orographic barrier from lowland climate station data. On an inter-annual basis, temperature, especially during the ablation season, had most influence on net accumulation, and warm summers served to homogenise winter variability. Consequently, atmospheric circulation patterns that affect summer temperature, for example the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) also influence inter-annual variability in net accumulation. Together, these results highlight the dependence of maritime glaciers in the New Zealand Southern Alps on the prevailing westerly circulation. Although some uncertainty surrounds how global warming will affect atmospheric circulation and synoptic weather patterns, the results of this research indicate that New Zealand glaciers can be expected to lose significant mass in the coming decades if the current positive trend in the SAM continues, and if La Niña events (positive ENSO) become more frequent.</p>

Controls on Spatial and Temporal Variation in Snow Accumulation on Glaciers in the Southern Alps, New Zealand

<p>Mountain glaciers are already responding to climatic warming, and are expected to make a substantial contribution to sea-level rise in the coming decades. The aim of this investigation in the New Zealand Southern Alps was to improve our understanding of snow accumulation variability on mid-latitude maritime glaciers, in order to allow for better estimation of future glacier mass balance. The specific aim was to investigate snow accumulation processes at a range of spatial and temporal scales, focussing on synoptic-scale atmospheric circulation influences, moisture sources for snow accumulation and local-scale dependencies of snow accumulation in relation to topography. A range of methods were utilised including direct measurement, snow and ice core analysis, statistical analysis and modelling. Snow accumulation in the Southern Alps was found to be derived predominantly from the Tasman Sea, and deposited during low pressure troughs and fronts. Although precipitation increased with elevation, wind processes redistributed this mass. On a ~monthly timescale this redistribution caused an unexpected result, namely that wind deflation of snow on Franz Josef Glacier countered the effects of greater accumulation, and total accumulation was similar at both Franz Josef and Tasman Glaciers over this period. These processes make it challenging to simulate snow accumulation patterns by simply extrapolating snowfall over an orographic barrier from lowland climate station data. On an inter-annual basis, temperature, especially during the ablation season, had most influence on net accumulation, and warm summers served to homogenise winter variability. Consequently, atmospheric circulation patterns that affect summer temperature, for example the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) also influence inter-annual variability in net accumulation. Together, these results highlight the dependence of maritime glaciers in the New Zealand Southern Alps on the prevailing westerly circulation. Although some uncertainty surrounds how global warming will affect atmospheric circulation and synoptic weather patterns, the results of this research indicate that New Zealand glaciers can be expected to lose significant mass in the coming decades if the current positive trend in the SAM continues, and if La Niña events (positive ENSO) become more frequent.</p>