Enteric Diseases in Alaska

Contains an historical account of past outbreaks of enteric diseases in arctic and subarctic Alaska. Only those caused by the Gram-negative bacteria of the genera Salmonella and Shigella are considered. Contaminated water supplies and inadequate sewage disposal have been the major causes of epidemics. 206 cases of typhoid fever are recorded for the period 1807-1952, and 230 cases of bacillary dysentery for the period 1937-51, with rates of fatalities, and type of infective agent, when known. This is revision of paper presented at Third Alaskan Science Conference, 1952. Author is Asst. Director, Public Health, Laboratories, Alaska Dept. of Health, Anchorage

Frederick A. Milan (1924-1995)

Frederick A. Milan died on 28 January 1995 after a series of strokes and related illness of several years. ... His activities around the polar regions of the world are well known and fondly remembered. Fred was Professor Emeritus of Human Ecology and Anthropology at the University of Alaska, Fairbanks. ... His work as an assistant on the Harvard Peabody Museum Anthropological Expedition to the Aleutian Islands in 1949 heightened his interest in the Arctic. It also impressed upon him the utility of studying Russian for understanding the history of the region. Fred worked in the summers of 1950 and 1952 as an archaeological assistant at Deering and Kodiak, Alaska. He was a weather observer on the Juneau Icefield Research Project in the summer of 1951. His major scholastic interests were in anthropology and linguistics, and he graduated in 1952. In 1953 Fred began several years of association with the former United States Air Force Arctic Aeromedical Laboratory near Fairbanks. ... [In 1954] he and other Arctic Aeromedical Laboratory personnel participated in the Mount Wrangell Research Project, a high-latitude cosmic ray study. His role was as a collaborator in a study of high altitude acclimatization of the team members. ... Fred undertook graduate study at several institutions: the Universities of Oregon, Wisconsin and Copenhagen, and the London School of Economics. His linguistic skills became well developed, and he was especially interested in the Inuit language and culture. He spent one winter in northern Sweden traveling and living with a nomadic Sami family. Back in Alaska in 1956, he began his close association with the Inupiat Eskimo village of Wainwright, Alaska. His ability to speak the language enabled him to gain the villagers' confidence and elicit genealogical information, and endeared him to the people. These activities led eventually to successful completion of his M.S. and Ph.D. degrees at the University of Wisconsin. ... In the 1960s Fred played an important role in establishing a worldwide study of northern people as part of the Human Adaptability section of the International Biological Program. ... He was a longtime advocate for multidisciplinary study of the needs for health care delivery and for the international exchange of information about circumpolar health problems and research efforts. In 1967 Fred, Dr. C. Earl Albrecht and colleagues in Alaska and other parts of the United States, Canada, Sweden, Norway, Denmark, Iceland, Greenland and the Union of Soviet Socialist Republics organized, with the support of the Arctic Institute of North America, the First International Symposium on Circumpolar Health. The symposium was held at Fairbanks in July 1967, and these meetings have continued at three-year intervals at various circumpolar locations. Fred was the president of the Sixth International Congress on Circumpolar Health held at Anchorage in 1984. ... During the 1970s and 1980s Fred was a faculty member at the University of Alaska, Fairbanks. He was a much-respected teacher, and he was noted for conveying his enthusiasm for scholarly work and his respect for the people of anthropological study to students and colleagues. The Fred Milan we knew was a genuine free spirit--he looked at the world through eyes wide with perceptive curiosity and interpreted it with kindness and good humor. We have been made richer and wiser by sharing in some of his generous and stimulating life

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation

Beam test performance of a prototype module with Short Strip ASICs for the CMS HL-LHC tracker upgrade

The Short Strip ASIC (SSA) is one of the four front-end chips designed for the upgrade of the CMS Outer Tracker for the High Luminosity LHC. Together with the Macro-Pixel ASIC (MPA) it will instrument modules containing a strip and a macro-pixel sensor stacked on top of each other. The SSA provides both full readout of the strip hit information when triggered, and, together with the MPA, correlated clusters called stubs from the two sensors for use by the CMS Level-1 (L1) trigger system. Results from the first prototype module consisting of a sensor and two SSA chips are presented. The prototype module has been characterized at the Fermilab Test Beam Facility using a 120 GeV proton beam

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.Peer reviewe

Selection of the silicon sensor thickness for the Phase-2 upgrade of the CMS Outer Tracker

During the operation of the CMS experiment at the High-Luminosity LHC the silicon sensors of the Phase-2 Outer Tracker will be exposed to radiation levels that could potentially deteriorate their performance. Previous studies had determined that planar float zone silicon with n-doped strips on a p-doped substrate was preferred over p-doped strips on an n-doped substrate. The last step in evaluating the optimal design for the mass production of about 200 m$^{2}$ of silicon sensors was to compare sensors of baseline thickness (about 300 μm) to thinned sensors (about 240 μm), which promised several benefits at high radiation levels because of the higher electric fields at the same bias voltage. This study provides a direct comparison of these two thicknesses in terms of sensor characteristics as well as charge collection and hit efficiency for fluences up to 1.5 × 10$^{15}$ n$_{eq}$/cm$^{2}$. The measurement results demonstrate that sensors with about 300 μm thickness will ensure excellent tracking performance even at the highest considered fluence levels expected for the Phase-2 Outer Tracker

Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation

The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×10$^{34}$ cm$^{-2}$s$^{-1}$. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment

Comparative evaluation of analogue front-end designs for the CMS Inner Tracker at the High Luminosity LHC

The CMS Inner Tracker, made of silicon pixel modules, will be entirely replaced prior to the start of the High Luminosity LHC period. One of the crucial components of the new Inner Tracker system is the readout chip, being developed by the RD53 Collaboration, and in particular its analogue front-end, which receives the signal from the sensor and digitizes it. Three different analogue front-ends (Synchronous, Linear, and Differential) were designed and implemented in the RD53A demonstrator chip. A dedicated evaluation program was carried out to select the most suitable design to build a radiation tolerant pixel detector able to sustain high particle rates with high efficiency and a small fraction of spurious pixel hits. The test results showed that all three analogue front-ends presented strong points, but also limitations. The Differential front-end demonstrated very low noise, but the threshold tuning became problematic after irradiation. Moreover, a saturation in the preamplifier feedback loop affected the return of the signal to baseline and thus increased the dead time. The Synchronous front-end showed very good timing performance, but also higher noise. For the Linear front-end all of the parameters were within specification, although this design had the largest time walk. This limitation was addressed and mitigated in an improved design. The analysis of the advantages and disadvantages of the three front-ends in the context of the CMS Inner Tracker operation requirements led to the selection of the improved design Linear front-end for integration in the final CMS readout chip

The CMS Phase-1 pixel detector upgrade

The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013–2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.Peer reviewe

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.