Constraints on the origin of the ultra-high energy cosmic-rays using cosmic diffuse neutrino flux limits: An analytical approach

Astrophysical neutrinos are expected to be produced in the interactions of ultra-high energy cosmic-rays with surrounding photons. The fluxes of the astrophysical neutrinos are highly dependent on the characteristics of the cosmic-ray sources, such as their cosmological distributions. We study possible constraints on the properties of cosmic-ray sources in a model-independent way using experimentally obtained diffuse neutrino flux above 100 PeV. The semi-analytic formula is derived to estimate the cosmogenic neutrino fluxes as functions of source evolution parameter and source extension in redshift. The obtained formula converts the upper-limits on the neutrino fluxes into the constraints on the cosmic-ray sources. It is found that the recently obtained upper-limit on the cosmogenic neutrinos by IceCube constrains the scenarios with strongly evolving ultra-high energy cosmic-ray sources, and the future limits from an 1 km^3 scale detector are able to further constrain the ultra-high energy cosmic-rays sources with evolutions comparable to the cosmic star formation rate.Comment: 9 pages, 3 figures and 1 table. Accepted by Phys. Rev.

Identifying High Energy Neutrino Transients by Neutrino Multiplet-Triggered Followups

Transient sources such as supernovae (SNe) and tidal disruption events are candidates of high energy neutrino sources. However, SNe commonly occur in the universe and a chance coincidence of their detection with a neutrino signal cannot be avoided, which may lead to a challenge of claiming their association with neutrino emission. In order to overcome this difficulty, we propose a search for $\sim10-100$ TeV neutrino multiple events within a timescale of $\sim 30$ days coming from the same direction, called neutrino multiplets. We show that demanding multiplet detection by a $\sim 1$ km$^3$ neutrino telescope limits distances of detectable neutrino sources, which enables us to identify source counterparts by multiwavelength observations owing to the substantially reduced rate of the chance coincidence detection of transients. We apply our results by constructing a feasible strategy for optical followup observations and demonstrate that wide-field optical telescopes with a $\gtrsim4$ m dish should be capable of identifying a transient associated with a neutrino multiplet. We also present the resultant sensitivity of multiplet neutrino detection as a function of the released energy of neutrinos and burst rate density. A model of neutrino transient sources with an emission energy greater than ${\rm a~few}\times 10^{51}$erg and a burst rate rarer than ${\rm a~few}\times 10^{-8}\ {\rm Mpc}^{-3}\ {\rm yr}^{-1}$ is constrained by the null detection of multiplets by a $\sim 1$km$^3$ scale neutrino telescope. This already disfavors the canonical high-luminosity gamma ray bursts and jetted tidal disruption events as major sources in the TeV-energy neutrino sky.Comment: The version accepted for publication in Ap

The EHE Neutrino Search Capability of the IceCube Observatory

An initial study of the extremely high energy (EHE) physics capabilityof the IceCube neutrino observatory is demonstrated by considering a GZK mechanism neutrino production model, which is a guaranteed source for EHE neutrinos. We study EHE event properties in the energy range $10^{5}$ $<$ E $<$ $10^{11}$ GeV observed by IceCube using detailed Monte Carlo simulation. Results of a simulation study show that about 0.7 EHE neutrino events per year is expected with the full IceCube configuration over a 0.03 atmospheric muon background which passed an EHE event criteria. It is also shown that with the present partial IceCube detector with the same criteria is capable of studying EHE physics and the sensitivity improves with the number of deployed strings in the ice.Comment: Proceedings of the Cosmic Ray International Seminar (CRIS 2006) on UHECR: Status and Perspective

Ward Chief Nurses' Perceptions and the Current Situation of Nurses' Career Development

目的：近畿，中国・四国地方の地域密着型病院の病棟看護師長のキャリアアップに対する認識と現状を明らかにする．方法：研究協力が得られた病棟看護師長187名に自記式質問紙調査を実施した．結果：101名（回収率54．0％）から回答が得られた．54名がスタッフに進学希望者がおり，それに対する思い・考えは【看護師個人の知識・スキルアップ・キャリアアップにつながる】【病棟・病院の看護の質向上が図れる】【病棟管理者としてスタッフの成長・キャリアアップを支援したい】の３つに分類された．支援はスタッフのキャリアプランの目標管理と学習への指導・助言，勤務調整・研修費などの体制支援を行っているが，スタッフのキャリアへの志向性が低い，人員不足・勤務業務調整が難しいなどの課題が明らかとなった．結論：病棟看護師長は，スタッフの成長と看護の質向上を期待し，キャリアアップへの課題に対する支援を模索していることが伺えた．Objective : To clarify the perceptions of ward chief nurses at community-based hospitals in the Kinki, Chugoku, and Shikoku regions, as well as the current situation regarding career development. Methods : We conducted a self-administered questionnaire survey of 187 ward chief nurses. Results : Responses were obtained from 101 chief nurses （response rate : 54.0%）. Of the respondents, 54 replied that their ward had staff members who desired more advanced education. Their thoughts/opinions about advanced education were classified as follows :［ it helps those nurses to advance their knowledge/skills/career］, ［it is helpful in improving the quality of nursing care in wards/hospitals］, and ［（they）, as ward managers, want to support staff members’ growth/career development］. Support provided to staff members included guidance/advice on goal management, learning for career development, and organizational support such as work shift adjustment and training fees. On the other hand, issues included staff members’ low career orientation, manpower shortages, and difficulties in work shift and duty adjustment. Conclusion : The ward chief nurses wanted to encourage staff members’ growth and qualitative improvements in nursing care and to explore support for career development issues

Ixodes persulcatus Ticks as Vectors for the Babesia microti U.S. Lineage in Japan

The U.S. lineage, one of the major clades in the Babesia microti group, is known as a causal agent of human babesiosis mostly in the northeastern and upper midwestern United States. This lineage, however, also is distributed throughout the temperate zone of Eurasia with several reported human cases, although convincing evidence of the identity of the specific vector(s) in this area is lacking. Here, the goal was to demonstrate the presence of infectious parasites directly in salivary glands of Ixodes persulcatus, from which U.S. lineage genetic sequences have been detected in Asia, and to molecularly characterize the isolates. Five PCR-positive specimens were individually inoculated into hamsters, resulting in infections in four; consequently, four strains were newly established. Molecular characterization, including 18S rRNA, β-tubulin, and CCT7 gene sequences, as well as Western blot analysis and indirect fluorescent antibody assay, revealed that all four strains were identical to each other and to the U.S. lineage strains isolated from rodents captured in Japan. The 18S rRNA gene sequence from the isolates was identical to those from I. persulcatus in Russia and China, but the genetic and antigenic profiles of the Japanese parasites differ from those in the United States and Europe. Together with previous epidemiological and transmission studies, we conclude that I. persulcatus is likely the principal vector for the B. microti U.S. lineage in Japan and presumably in northeastern Eurasia. IMPORTANCE The major cause of human babesiosis, the tick-borne blood parasite Babesia microti, U.S. lineage, is widely distributed in the temperate Northern Hemisphere. However, the specific tick vector(s) remains unidentified in Eurasia, where there are people with antibodies to the B. microti U.S. lineage and cases of human babesiosis. In this study, the first isolation of B. microti U.S. lineage from Ixodes persulcatus ticks, a principal vector for many tick-borne diseases, is described in Japan. Limited antigenic cross-reaction was found between the Japan and United States isolates. Thus, current serological tests based on U.S. isolates may underestimate B. microti occurrence outside the United States. This study and previous studies indicate that I. persulcatus is part of the B. microti U.S. lineage life cycle in Japan and, presumably, northeastern Eurasia. This report will be important for public health, especially since infection may occur through transfusion, and also to researchers in the field of parasitology