Heterogeneity of meningeal B cells reveals a lymphopoietic niche at the CNS borders

The meninges contain adaptive immune cells that provide immunosurveillance of the CNS. These cells are thought to derive from the systemic circulation. Through single-cell analyses, confocal imaging, bone marrow chimeras, and parabiosis experiments, we show that meningeal B cells derive locally from the calvaria, which harbors a bone marrow niche for hematopoiesis. B cells reach the meninges from the calvaria through specialized vascular connections. This calvarial–meningeal path of B cell development may provide the CNS with a constant supply of B cells educated by CNS antigens. Conversely, we show that a subset of antigen-experienced B cells that populate the meninges in aging mice are blood-borne. These results identify a private source for meningeal B cells. which may help maintain immune privilege within the CNS.

Practical No-Signalling proof Randomness Amplification using Hardy paradoxes and its experimental implementation

Device-Independent (DI) security is the gold standard of quantum cryptography, providing information-theoretic security based on the very laws of nature. In its highest form, security is guaranteed against adversaries limited only by the no-superluminal signalling rule of relativity. The task of randomness amplification, to generate secure fully uniform bits starting from weakly random seeds, is of both cryptographic and foundational interest, being important for the generation of cryptographically secure random numbers as well as bringing deep connections to the existence of free-will. DI no-signalling proof protocols for this fundamental task have thus far relied on esoteric proofs of non-locality termed pseudo-telepathy games, complicated multi-party setups or high-dimensional quantum systems, and have remained out of reach of experimental implementation. In this paper, we construct the first practically relevant no-signalling proof DI protocols for randomness amplification based on the simplest proofs of Bell non-locality and illustrate them with an experimental implementation in a quantum optical setup using polarised photons. Technically, we relate the problem to the vast field of Hardy paradoxes, without which it would be impossible to achieve amplification of arbitrarily weak sources in the simplest Bell non-locality scenario consisting of two parties choosing between two binary inputs. Furthermore, we identify a deep connection between proofs of the celebrated Kochen-Specker theorem and Hardy paradoxes that enables us to construct Hardy paradoxes with the non-zero probability taking any value in (0,1]. Our methods enable us, under the fair-sampling assumption of the experiment, to realize up to 25 bits of randomness in 20 hours of experimental data collection from an initial private source of randomness 0.1 away from uniform.

Socio-demographic characteristics of persons with psychiatric disorders who committed suicide

Introduction. Psychiatric disorders represent an important risk factor for death by suicide. The aim of this study was to assess the incidence of psychiatric disorders among the persons who committed suicide in the territory of the City of Nis in the period 2001 - 2010. Additionally, this study aimed to compare the socio-demographic characteristics between persons with and without psychiatric disorders. Material and methods. This retrospective study included 524 persons who committed suicide (330 with and 194 without psychiatric disorders) in the period 2001 - 2010. Data on socio-demographic characteristics, previous suicide attempts, and methods of suicide were obtained from medical and police records (Police Directorate for the City of Nis, and Statistical Office of the Republic of Serbia). Results. We studied the incidence of suicides among the persons with psychiatric disorders compared to persons without any medical condition in the studied period. Depression (104, 31.5%) and personality disorders (103, 31.2%) were the most common psychiatric disorders among the persons who committed suicide, whereas only 21 persons (6.36%) had schizophrenia. Persons with psychiatric disorders had a higher level of education, more of them were divorced, had a private source of income and more frequently attempted suicide compared to persons without any diseases (p<0.001). The most common methods of suicide were hanging and poisoning in both investigated groups. Conclusion. Depression was the most common disorder registered among the persons with psychiatric disorders who committed suicide. It is necessary to develop a national strategy for suicide prevention for groups at high risk of suicide.

TRENDS

THE origins and initial operations of Playtex Park Research Institute in support of pediatric research were reported in this column a year and a half ago. When the Institute was founded by the International Latex Corporation it was described as "an experiment in industrial giving." The accomplishments of the Institute to date justify the faith that the sponsor and the governing board had in the concept that industry and medicine can work as a team for the common good with great effectiveness. The medical world is well aware of the ever present necessity for the private augmentation of the pitifully small existing funds for pediatric research. It is indeed fortunate that Playtex Park Research Institute is the beneficiary of its sponsor's realistic and farsighted approach to this need. In the short period of less than three years, the Institute has received almost $700,000.00 in commitments from the International Latex Corporation which is indeed a generous contribution to the advancement of pediatric knowledge. This has made the Institute's sponsor the largest private source of funds for pediatric research in the country, and possibly the world. The sponsor insists on taking no part in deciding how this money is spent. Reflecting these wishes, such jurisdiction is placed solely in the hands of the 25 physicians comprising the Institute's Board of Governors.