Space cowboys odyssey: beyond the Gould Belt

We present our new advanced model for population synthesis of close-by cooling NSs. Detailed treatment of the initial spatial distribution of NS progenitors and a detailed ISM structure up to 3 kpc give us an opportunity to discuss the strategy to look for new isolated cooling NSs. Our main results in this respect are the following: new candidates are expected to be identified behind the Gould Belt, in directions to rich OB associations, in particular in the Cygnus-Cepheus region; new candidates, on average, are expected to be hotter than the known population of cooling NS. Besides the usual approach (looking for soft X-ray sources), the search in 'empty' $\gamma$-ray error boxes or among run-away OB stars may yield new X-ray thermally emitting NS candidates.Comment: 3 pages, 2 figures, proceedings of the conference "40 Years of Pulsars ", 12-17 August 2007, Montreal, Canad

Neutron Stars: Formed, Spun and Kicked

One of the primary goals when studying stellar systems with neutron stars has been to reveal the physical properties of progenitors and understand how neutron star spins and birth kicks are determined. Over the years a consensus understanding had been developed, but recently some of the basic elements of this understanding are being challenged by current observations of some binary systems and their theoretical interpretation. In what follows we review such recent developments and highlight how they are interconnected; we particularly emphasize some of the assumptions and caveats of theoretical interpretations and examine their validity (e.g., in connection to the unknown radial velocities of pulsars or the nuances of multi-dimensional statistical analysis). The emerging picture does not erase our earlier understanding; instead it broadens it as it reveals additional pathways for neutron star formation and evolution: neutron stars probably form at the end of both core collapse of Fe cores of massive stars and electron-capture supernovae of ONeMg cores of lower-mass stars; birth kicks are required to be high (well in excess of 100 km/s) for some neutron stars and low (< 100 km/s) for others depending on the formation process; and spin up may occur not just through Roche-lobe overflow but also through wind accretion or phases of hypercritical accretion during common envelope evolution.Comment: 9 pages,4 figures, proceedings paper for 40 Years of Pulsars Conferenc

Conditional Allocation of Control Rights in Venture Capital Finance

When a young entrepreneurial firm matures, it is often necessary to replace the founding entrepreneur by a professional manager. This replacement decision can be affected by the private benefits of control enjoyed by the entrepreneur which gives rise to a conflict of interest between the entrepreneur and the venture capitalist. We show that a combination of convertible securities and contingent control rights can be used to resolve this conflict efficiently. This contractual arrangement is frequently observed in venture capital finance

Mitigation of Moral Hazard and Adverse Selection in Venture Capital Financing: The Influence of the Country’s Institutional Setting

A venture capitalist (VC) needs to trade off benefits and costs when attempting to mitigate agency problems in their investor-investee relationship. We argue that signals of ventures complement the VC’s capacity to screen and conduct a due diligence during the pre-investment phase, but its attractiveness may diminish in institutional settings supporting greater transparency. Similarly, whereas a VC may opt for contractual covenants to curb potential opportunism by ventures in the post-investment phase, this may only be effective in settings supportive of shareholder rights enforcement. Using an international sample of VC contracts, our study finds broad support for these conjectures. It delineates theoretical and practical implications for how investors can best deploy their capital in different institutional settings whilst nurturing their relationships with entrepreneurs

Evaluating Calculated Free Testosterone as a Predictor of Morbidity and Mortality Independent of Testosterone for Cross-sectional and 5-Year Longitudinal Health Outcomes in Older Men: The Concord Health and Ageing in Men Project

To determine whether calculated free testosterone (cFT) provides prognostic information independent of serum T for predicting morbidity and mortality in older men in cross-sectional and 5-year longitudinal analyses. We studied men aged ≥70 years at baseline (n = 1,705), 2-year and 5-year measuring serum T (liquid chromatography-mass spectrometry), SHBG (immunoassay), cFT (an assumption-free empirical formula) together with 24 morbidity and 4 mortality outcomes. For cross-sectional and longitudinal analyses we employed a joint prediction model using generalized estimating equation models adjusted for age, smoking, comorbidities, and body mass index (BMI) with men having both normal T and normal cFT as referent group. Most morbidity and mortality outcomes were predicted by a combination of low T and cFT (LL). By contrast, only a single morbidity outcome in cross-sectional and none in longitudinal analysis was predicted by low T/normal cFT (LN) or normal T/low cFT (NL) without significant LL associations (isolated discordance). While for the few outcomes that predicted morbidity in men with discordances (LN or NL), these predictions only occurred when LL was also significant. Hence, for morbidity or mortality prediction in older men, discordance between cFT and T is unusual and isolated discordance is rare, so that cFT provides minimal independent prognostic information over serum T.NHMRC, Sydney Medical School Foundation, and Ageing and Alzheimer’s Institute

Zeeman tomography of magnetic white dwarfs. II, The quadrupole-dominated magnetic field of HE 1045-0908

We report time-resolved optical flux and circular polarization spectroscopy of the magnetic DA white dwarf HE 1045−0908 obtained with FORS1 at the ESO VLT. Considering published results, we estimate a likely rotational period of P rot 2.7 h, but cannot exclude values as high as about 9 h. Our detailed Zeeman tomographic analysis reveals a field structure which is dominated by a quadrupole and contains additional dipole and octupole contributions, and which does not depend strongly on the assumed value of the period. A good fit to the Zeeman flux and polarization spectra is obtained if all field components are centred and inclinations of their magnetic axes with respect to each other are allowed for. The fit can be slightly improved if an offset from the centre of the star is included. The prevailing surface field strength is 16 MG, but values between 10 and ∼ 75 MG do occur. We derive an effective photospheric temperature of HE 1045−0908 of T eff = 10 000 ± 1000 K. The tomographic code makes use of an extensive database of pre-computed Zeeman spectra (Paper I)

Machine Learning Models that Remember Too Much

Machine learning (ML) is becoming a commodity. Numerous ML frameworks and services are available to data holders who are not ML experts but want to train predictive models on their data. It is important that ML models trained on sensitive inputs (e.g., personal images or documents) not leak too much information about the training data. We consider a malicious ML provider who supplies model-training code to the data holder, does not observe the training, but then obtains white- or black-box access to the resulting model. In this setting, we design and implement practical algorithms, some of them very similar to standard ML techniques such as regularization and data augmentation, that "memorize" information about the training dataset in the model yet the model is as accurate and predictive as a conventionally trained model. We then explain how the adversary can extract memorized information from the model. We evaluate our techniques on standard ML tasks for image classification (CIFAR10), face recognition (LFW and FaceScrub), and text analysis (20 Newsgroups and IMDB). In all cases, we show how our algorithms create models that have high predictive power yet allow accurate extraction of subsets of their training data

Nanotechnology in multimodal theranostic capsule endoscopy

Video capsule endoscopy (VCE) has become a clinically accepted diagnostic modality in the last 20 years and has established a technological roadmap for other capsule endoscopy (CE) devices, incorporating microscale technology, a local power supply and wireless communication. However, VCE does not provide a therapeutic function and research in therapeutic capsule endoscopy (TCE) has been limited. This paper proposes a new route towards viable TCE based on multiple CE devices including essential nanoscale components. A first device is used for multimodal diagnosis, with quantitative microultrasound as a complement to video imaging. Ultrasound-enhanced fluorescent marking of sites of pathology allows follow-up with a second device for therapy. This is based on fluorescence imaging and ultrasound-mediated targeted drug delivery. Subsequent treatment verification and monitoring with a third device exploits the minimally invasive nature of CE. Clinical implementation of a complete patient pathway remains the subject of research but several key components have been prepared in early prototype form. These are described, along with gaps that remain to be filled

Community-dwelling men with dementia are at high risk of hip but not any other fracture: The Concord Health and Ageing in Men Project

Aim The aim of the present longitudinal study of community‐dwelling older men was to examine the association between cognitive status at baseline, and falls, fractures and bone loss over time. Methods In the Concord Health and Aging in Men Project, 1705 community‐dwelling men aged 70–97 years had detailed baseline clinical assessment of cognitive status (dementia, mild cognitive impairment [MCI] and normal cognition), as well as depression, physical activity, neuromuscular function, health status, sociodemographics, comorbidities, medication use and serum 25 hydroxyvitamin D, 1,25 dihydroxyvitamin D and parathyroid hormone levels. During a mean follow‐up period of 6 years, participants were contacted 4‐monthly to ascertain incident falls and fractures, the latter being confirmed by radiographic reports. Bone mineral density was measured by dual X‐ray absorptiometry at multiple time‐points. Results At baseline, 120 men were assessed to have MCI and 93 men to have dementia. Over time, there were 162 first incident fractures, including 43 hip and 32 vertebral fractures. In univariate models, baseline dementia, but not MCI, predicted an increased incidence of hip fracture (HR 6.95, 95% CI 3.47–13.96), but not vertebral (HR 2.26, 95% CI 0.79–6.46) or non‐hip non‐vertebral fracture (HR 0.73, 95% CI 0.27–1.99). The strong risk of hip fractures associated with dementia remained after accounting for potential confounders (HR 4.44, 95% CI 1.97–9.98). In multivariate analyses, dementia (incidence rate ratio 2.26, 95% CI 1.70–2.99), but not MCI, was associated with an increased risk of falls compared with normal cognition. There was no association between baseline dementia and change in bone mineral density. Conclusions Older men with dementia, but not MCI, have a greater tendency to fall and sustain hip fractures, but not any other types of fractures.NHMRC, Ageing and Alzheimer's Institute, Sydney Medical School Foundatio