A law of the iterated logarithm for Grenander's estimator

In this note we prove the following law of the iterated logarithm for the Grenander estimator of a monotone decreasing density: If $f(t_0) > 0$, $f'(t_0) < 0$, and $f'$ is continuous in a neighborhood of $t_0$, then \begin{eqnarray*} \limsup_{n\rightarrow \infty} \left ( \frac{n}{2\log \log n} \right )^{1/3} ( \widehat{f}_n (t_0 ) - f(t_0) ) = \left| f(t_0) f'(t_0)/2 \right|^{1/3} 2M \end{eqnarray*} almost surely where $M \equiv \sup_{g \in {\cal G}} T_g = (3/4)^{1/3}$ and T_g \equiv \mbox{argmax}_u \{ g(u) - u^2 \} ; here ${\cal G}$ is the two-sided Strassen limit set on $R$. The proof relies on laws of the iterated logarithm for local empirical processes, Groeneboom's switching relation, and properties of Strassen's limit set analogous to distributional properties of Brownian motion.Comment: 11 pages, 3 figure

Induction of specific tolerance by intrathymic injection of recipient muscle cells transfected with donor class I major histocompatibility complex.

Induction of tolerance to allogeneic MHC antigens has been a goal in the field of transplantation because it would reduce or eliminate the need for generalized immunosuppression. Although encouraging results have been obtained in experimental models by exposing recipient thymus to donor cells before transplantation, donor cells are not typically available at that time, and the donor antigens responsible for the effect are poorly defined. In the present study, thymic tolerance was demonstrated without using donor cells. Recipient thymus was injected before transplantation with autologous myoblasts and myotubes that were genetically modified to express allogeneic donor-type MHC class I antigen. Donor-specific unresponsiveness was induced to a completely MHC-disparate liver transplant and to a subsequent donor-type cardiac allograft, but not a third-party allograft. In vitro, recipient CTL demonstrated a 10-fold reduction in killing of donor cells, but not of third-party cells. Our results demonstrate: (1) that recipient muscle cells can be genetically engineered to induce donor-specific unresponsiveness when given intrathymically, and (2) transfected recipient cells expressing only donor MHC class I antigen can induce tolerance to a fully allogeneic donor

(S)-(+)-Ketamine hydro­chloride

The crystal structure of the title compound {systematic name: (S)-(+)-N-[1-(2-chloro­phen­yl)-2-oxocyclo­hexyl]meth­anam­in­ium chloride}, C13H17ClNO+·Cl−, was determined at 90 (2) K. The (S)-(+)-ketamine hydro­chloride salt is a well known anesthetic compound and is dramatically more potent than its R isomer. In the title compound, the cyclo­hexa­none ring adopts a chair conformation with the oxo group in the equatorial orientation. The methyl­amino and 2-chloro­phenyl groups at the 2-position have an equatorial and an axial orientation, respectively. The packing of ions is stabilized by an infinite one-dimensional ⋯Cl⋯H—N—H⋯Cl⋯ hydrogen-bonding network, involving NH2 + groups as donors and chloride anions as acceptors

Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm2/cm3 surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm3 scaffold with about 16,000 interconnected channels (about 1 m2 surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structuredchannels. The fabricated scaffoldswere applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6× 4mm) were tested for cell culturing and could support homogeneous cell growth throughoutthe scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive

Making Urban Slum Population Visible: Citizens and Satellites to Reinforce Slum Censuses

In response to the “Leave No One Behind” principle (the central promise of the 2030 Agenda for Sustainable Development), reliable estimate of the total number of citizens living in slums is urgently needed but not available for some of the most vulnerable communities. Not having a reliable estimate of the number of poor urban dwellers limits evidence-based decision-making for proper resource allocation in the fight against urban inequalities. From a geographical perspective, urban population distribution maps in many low- and middle-income cities are most often derived from outdated or unreliable census data disaggregated by coarse administrative units. Moreover, slum populations are presented as aggregated within bigger administrative areas, leading to a large diffuse in the estimates. Existing global and open population databases provide homogeneously disaggregated information (i.e. in a spatial grid), but they mostly rely on census data to generate their estimates, so they do not provide additional information on the slum population. While a few studies have focused on bottom-up geospatial models for slum population mapping using survey data, geospatial covariates, and earth observation imagery, there is still a significant gap in methodological approaches for producing precise estimates within slums. To address this issue, we designed a pilot experiment to explore new avenues. We conducted this study in the slums of Nairobi, where we collected in situ data together with slum dwellers using a novel data collection protocol. Our results show that the combination of satellite imagery with in situ data collected by citizen science paves the way for generalisable, gridded estimates of slum populations. Furthermore, we find that the urban physiognomy of slums and population distribution patterns are related, which allows for highlighting the diversity of such patterns using earth observation within and between slums of the same city

Persistent influence of obliquity on ice age terminations since the Middle Pleistocene transition.

Radiometric dating of glacial terminations over the past 640,000 years suggests pacing by Earth's climatic precession, with each glacial-interglacial period spanning four or five cycles of ~20,000 years. However, the lack of firm age estimates for older Pleistocene terminations confounds attempts to test the persistence of precession forcing. We combine an Italian speleothem record anchored by a uranium-lead chronology with North Atlantic ocean data to show that the first two deglaciations of the so-called 100,000-year world are separated by two obliquity cycles, with each termination starting at the same high phase of obliquity, but at opposing phases of precession. An assessment of 11 radiometrically dated terminations spanning the past million years suggests that obliquity exerted a persistent influence on not only their initiation but also their duration