Weight filtration on the cohomology of complex analytic spaces

We extend Deligne's weight filtration to the integer cohomology of complex analytic spaces (endowed with an equivalence class of compactifications). In general, the weight filtration that we obtain is not part of a mixed Hodge structure. Our purely geometric proof is based on cubical descent for resolution of singularities and Poincar\'e-Verdier duality. Using similar techniques, we introduce the singularity filtration on the cohomology of compactificable analytic spaces. This is a new and natural analytic invariant which does not depend on the equivalence class of compactifications and is related to the weight filtration.Comment: examples added + minor correction

Trust economics feasibility study

We believe that enterprises and other organisations currently lack sophisticated methods and tools to determine if and how IT changes should be introduced in an organisation, such that objective, measurable goals are met. This is especially true when dealing with security-related IT decisions. We report on a feasibility study, Trust Economics, conducted to demonstrate that such methodology can be developed. Assuming a deep understanding of the IT involved, the main components of our trust economics approach are: (i) assess the economic or financial impact of IT security solutions; (ii) determine how humans interact with or respond to IT security solutions; (iii) based on above, use probabilistic and stochastic modelling tools to analyse the consequences of IT security decisions. In the feasibility study we apply the trust economics methodology to address how enterprises should protect themselves against accidental or malicious misuse of USB memory sticks, an acute problem in many industries

The Mass-to-Light Ratio of Binary Galaxies

We report on the mass-to-light ratio determination based on a newly selected binary galaxy sample, which includes a large number of pairs whose separations exceed a few hundred kpc. The probability distributions of the projected separation and the velocity difference have been calculated considering the contamination of optical pairs, and the mass-to-light ratio has been determined based on the maximum likelihood method. The best estimate of $M/L$ in the B band for 57 pairs is found to be 28 $\sim$ 36 depending on the orbital parameters and the distribution of optical pairs (solar unit, $H_0=50$ km s$^{-1}$ Mpc$^{-1}$). The best estimate of $M/L$ for 30 pure spiral pairs is found to be 12 $\sim$ 16. These results are relatively smaller than those obtained in previous studies, but consistent with each other within the errors. Although the number of pairs with large separation is significantly increased compared to previous samples, $M/L$ does not show any tendency of increase, but found to be almost independent of the separation of pairs beyond 100 kpc. The constancy of $M/L$ beyond 100 kpc may indicate that the typical halo size of spiral galaxies is less than $\sim 100$ kpc.Comment: 18 pages + 8 figures, to appear in ApJ Vol. 516 (May 10

On-the-fly Uniformization of Time-Inhomogeneous Infinite Markov Population Models

This paper presents an on-the-fly uniformization technique for the analysis of time-inhomogeneous Markov population models. This technique is applicable to models with infinite state spaces and unbounded rates, which are, for instance, encountered in the realm of biochemical reaction networks. To deal with the infinite state space, we dynamically maintain a finite subset of the states where most of the probability mass is located. This approach yields an underapproximation of the original, infinite system. We present experimental results to show the applicability of our technique

CO(1-0) survey of high-z radio galaxies: alignment of molecular halo gas with distant radio sources

We present a CO(1–0) survey for cold molecular gas in a representative sample of 13 highz radio galaxies (HzRGs) at 1.4 <z< 2.8, using the Australia Telescope Compact Array. We detect CO(1–0) emission associated with five sources: MRC 0114-211, MRC 0152-209, MRC 0156-252, MRC 1138-262 and MRC 2048-272. The CO(1–0) luminosities are in the range L CO ∼ (5–9) × 1010 K km s−1 pc2. For MRC 0152-209 and MRC 1138-262, part of the CO(1–0) emission coincides with the radio galaxy, while part is spread on scales of tens of kpc and likely associated with galaxy mergers. The molecular gas mass derived for these two systems is MH2 ∼ 6 × 1010 M� (MH2/L CO = 0.8). For the remaining three CO-detected sources, the CO(1–0) emission is located in the halo (∼50-kpc) environment. These three HzRGs are among the fainter far-IR emitters in our sample, suggesting that similar reservoirs of cold molecular halo gas may have been missed in earlier studies due to pre-selection of IR-bright sources. In all three cases, the CO(1–0) is aligned along the radio axis and found beyond the brightest radio hotspot, in a region devoid of 4.5 µm emission in Spitzerimaging. The CO(1–0) profiles are broad, with velocity widths of ∼1000–3600 km s−1. We discuss several possible scenarios to explain these halo reservoirs of CO(1–0). Following these results, we complement our CO(1–0) study with detections of extended CO from the literature and find at marginal statistical significance (95 per cent level) that CO in HzRGs is preferentially aligned towards the radio jet axis. For the eight sources in which we do not detect CO(1–0), we set realistic upper limits of L CO ∼ 3–4 × 1010 K km s−1 pc2. Our survey reveals a CO(1–0) detection rate of 38 per cent, allowing us to compare the CO(1–0) content of HzRGs with that of other types of high-z galaxies

The Discovery of Radio Stars within 10 arcseconds of Sgr A* at 7mm

Very Large Array observations of the Galactic Center at 7 mm have produced an image of the 30 arcseconds surrounding Sgr A* with a resolution of 82x42 milliarcseconds (mas). A comparison with IR images taken simultaneously with the Very Large Telescope (VLT) identifies 41 radio sources with L-band (3.8 microns) stellar counterparts. The well-known young, massive stars in the central Sgr A* cluster (e.g., IRS 16C, IRS 16NE, IRS 16SE2, IRS 16NW, IRS 16SW, AF, AFNW, IRS 34W and IRS 33E) are detected with peak flux densities between 0.2 and 1.3 mJy. The origin of the stellar radio emission in the central cluster is discussed in terms of ionized stellar winds with mass-loss rates in the range 0.8-5x10^{-5} solar mass per year. Radio emission from eight massive stars is used as a tool for registration between the radio and infrared frames with mas precision within a few arcseconds of Sgr A*. This is similar to the established technique of aligning SiO masers and evolved stars except that radio stars lie within a few arcseconds of Sgr A*. Our data show a scatter of ~6.5 mas in the positions of the eight radio sources that appear in both the L-band and 7 mm images. Lastly, we use the radio and IR data to argue that members of IRS 13N are Young Stellar Objects rather than dust clumps, supporting the hypothesis that recent star formation has occurred near Sgr A*.Comment: 15 pages, 3 figures, ApJL (in press

Simple Nudges for Better Password Creation

Recent security breaches have highlighted the consequences of reusing passwords across online accounts. Recent guidance on password policies by the UK government recommend an emphasis on password length over an extended character set for generating secure but memorable passwords without cognitive overload. This paper explores the role of three nudges in creating website-specific passwords: financial incentive (present vs absent), length instruction (long password vs no instruction) and stimulus (picture present vs not present). Mechanical Turk workers were asked to create a password in one of these conditions and the resulting passwords were evaluated based on character length, resistance to automated guessing attacks, and time taken to create the password. We found that users created longer passwords when asked to do so or when given a financial incentive and these longer passwords were harder to guess than passwords created with no instruction. Using a picture nudge to support password creation did not lead to passwords that were either longer or more resistant to attacks but did lead to account-specific passwords

Monocyte derived macrophages from lung transplantation patients have an increased M2 profile

Introduction: Lung transplantation (LTx) is a last treatment option for patients with an end-stage pulmonary disease. Although the monocyte-macrophage lineage is accepted to be clinically important only little is known about the effect of immunosuppressive drugs in combination with chronic rejection. It is likely that local inflammatory conditions and immunosuppressive medication alter the activation state of macrophages. The goal of this study was to determine how monocyte derived macrophage subsets were affected in LTx patients. Methods: PBMC's were obtained by ficoll density gradient centrifugation and cultured in RPMI with 10% FCS for 7 days. For identification and quantification of cultured monocyte derived macrophages fluorescence-activated cell sorting analysis was performed. Markers including; CD16, CD64, CD200r, CD163 and CD14 were used to determine M1, M2a and M2b macrophages. Results: Transplantation patients showed an increased and frequency (p = 0.0245) for M2a macrophages compared to healthy controls. Also, median fluorescence intensity of CD163, CD64, HLA-DR and CD200r increased with transplantation. Discussion: An increase in M2 phenotype macrophages in transplantation patients is in line with the latest findings in solid organ transplantation. M2 macrophages are associated with tissue-regeneration and diminished capacity of host defence, possibly leading to fibrosis development [1]. What this exactly means for the disease process and current clinical assessment requires further investigation

Functional diversity can facilitate the collapse of an undesirable ecosystem state

Biodiversity may increase ecosystem resilience. However, we have limited understanding if this holds true for ecosystems that respond to gradual environmental change with abrupt shifts to an alternative state. We used a mathematical model of anoxic–oxic regime shifts and explored how trait diversity in three groups of bacteria influences resilience. We found that trait diversity did not always increase resilience: greater diversity in two of the groups increased but in one group decreased resilience of their preferred ecosystem state. We also found that simultaneous trait diversity in multiple groups often led to reduced or erased diversity effects. Overall, our results suggest that higher diversity can increase resilience but can also promote collapse when diversity occurs in a functional group that negatively influences the state it occurs in. We propose this mechanism as a potential management approach to facilitate the recovery of a desired ecosystem state

The influence of bright and dim light on substrate metabolism, energy expenditure and thermoregulation in insulin-resistant individuals depends on time of day

AIMS/HYPOTHESIS: In our modern society, artificial light is available around the clock and most people expose themselves to electrical light and light-emissive screens during the dark period of the natural light/dark cycle. Such suboptimal lighting conditions have been associated with adverse metabolic effects, and redesigning indoor lighting conditions to mimic the natural light/dark cycle more closely holds promise to improve metabolic health. Our objective was to compare metabolic responses to lighting conditions that resemble the natural light/dark cycle in contrast to suboptimal lighting in individuals at risk of developing metabolic diseases. METHODS: Therefore, we here performed a non-blinded, randomised, controlled, crossover trial in which overweight insulin-resistant volunteers (n = 14) were exposed to two 40 h laboratory sessions with different 24 h lighting protocols while staying in a metabolic chamber under real-life conditions. In the Bright day–Dim evening condition, volunteers were exposed to electric bright light (~1250 lx) during the daytime (08:00–18:00 h) and to dim light (~5 lx) during the evening (18:00–23:00 h). Vice versa, in the Dim day–Bright evening condition, volunteers were exposed to dim light during the daytime and bright light during the evening. Randomisation and allocation to light conditions were carried out by sequential numbering. During both lighting protocols, we performed 24 h indirect calorimetry, and continuous core body and skin temperature measurements, and took frequent blood samples. The primary outcome was plasma glucose focusing on the pre- and postprandial periods of the intervention. RESULTS: Spending the day in bright light resulted in a greater increase in postprandial triacylglycerol levels following breakfast, but lower glucose levels preceding the dinner meal at 18:00 h, compared with dim light (5.0 ± 0.2 vs 5.2 ± 0.2 mmol/l, n = 13, p=0.02). Dim day–Bright evening reduced the increase in postprandial glucose after dinner compared with Bright day–Dim evening (incremental AUC: 307 ± 55 vs 394 ± 66 mmol/l × min, n = 13, p=0.009). After the Bright day–Dim evening condition the sleeping metabolic rate was identical compared with the baseline night, whereas it dropped after Dim day–Bright evening. Melatonin secretion in the evening was strongly suppressed for Dim day–Bright evening but not for Bright day–Dim evening. Distal skin temperature for Bright day–Dim evening was lower at 18:00 h (28.8 ± 0.3°C vs 29.9 ± 0.4°C, n = 13, p=0.039) and higher at 23:00 h compared with Dim day–Bright evening (30.1 ± 0.3°C vs 28.8 ± 0.3°C, n = 13, p=0.006). Fasting and postprandial plasma insulin levels and the respiratory exchange ratio were not different between the two lighting protocols at any time. CONCLUSIONS/INTERPRETATION: Together, these findings suggest that the indoor light environment modulates postprandial substrate handling, energy expenditure and thermoregulation of insulin-resistant volunteers in a time-of-day-dependent manner. TRIAL REGISTRATION: ClinicalTrials.gov NCT03829982. FUNDING: We acknowledge the financial support from the Netherlands Cardiovascular Research Initiative: an initiative with support from the Dutch Heart Foundation (CVON2014–02 ENERGISE). GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains peer-reviewed but unedited supplementary material available at 10.1007/s00125-021-05643-9