Letters from Chas. Eldered Shelton, John L. Tilton, George Clammer, and Wallace R. Lane

Letters concerning A. G. Reid, an applicant for position in athletic department at Utah Agricultural College

The Effect of Basal Diet on Lactate-Producing Bacteria and the Susceptibility of Sheep to Lactic Acidosis

The influence of a diet of either pasture or hay on the development of lactic acidosis in sheep was investigated using a grain challenge approach. Twenty-four Merino wethers with a mean live weight of 36.7 (s.e. 3.6) kg were used; 12 were adapted to grass pasture and 12 to hay (lucerne and oaten hay, 60 : 40) for 4 weeks before being given 1 kg of crushed barley via stomach tube. Six sheep in each group were also given virginiamycin (VM; 50 mg/kg barley) with the grain to test the efficacy of this antibiotic in controlling the bacteria responsible for the development of acidosis. Changes in volatile fatty acid (VFA), pH, lactate and bacterial count in the rumen and faecal pH and dry matter (DM) were measured for a 24-h period following administration of the barley. Daily intakes of hay were measured for a 10-day period following grain engorgement. Total ruminal VFA increased (P < 0.01) over time and tended (P = 0.08) to be higher in sheep adapted to hay than in those adapted to pasture (67.5 v. 59.8 mmol/l). The molar proportions of VFA changed (P< 0.01) over time in favour of propionate in both groups. Ruminal pH was higher (P< 0.001) in pasture-adapted sheep, but declined (P< 0.001) in both groups over time following the introduction of barley. This decline in pH was associated with increases in ruminal concentration of VFA in pasture-adapted sheep and VFA and lactate in hay-adapted sheep. The addition of VM resulted in a higher (P < 0.001) proportion of propionate and a trend towards higher (P = 0.24) faecal pH and DM content. Faecal pH and DM content declined (P < 0.001) over time and was lower for the pasture-adapted sheep. The introduction of either barley alone or barley with VM from both hay and pasture diets increased (P < 0.05) the viable counts of total bacteria, Streptococcus bovis and lactic acid bacteria. Bacterial isolates were purified and identified by complete sequencing of the 16S rRNA gene to determine the predominant bacteria during the overfeeding of grain. Isolates from medium selective for S. bovis were all identified as this species when VM was not given. VM had no effect on counts of viable bacteria, but inhibited the growth of S. bovis

FU Orionis resolved by infrared long baseline interferometry at a 2-AU scale

We present the first infrared interferometric observations of a young stellar object with a spatial projected resolution better than 2 AU. The observations were obtained with the Palomar Testbed Interferometer. FU Ori exhibits a visibility of V^2 =0.72 +/- 0.07 for a 103 +/- 5 m projected baseline at lambda = 2.2 microns. The data are consistent on the spatial scale probed by PTI both with a binary system scenario (maximum magnitude difference of 2.7 +/- 0.5 mag and smallest separation of 0.35 +/- 0.05 AU) and a standard luminous accretion disk model (approx. accretion rate of 6e-5 Mo/yr) where the thermal emission dominates the stellar scattering, and inconsistent with a single stellar photosphere.Comment: 13 pages, 4 figures, accepted for publication in ApJ

Historically unprecedented Northern Gulf of Mexico hurricane activity from 650 to 1250 CE

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rodysill, J. R., Donnelly, J. P., Sullivan, R., Lane, P. D., Toomey, M., Woodruff, J. D., Hawkes, A. D., MacDonald, D., d'Entremont, N., McKeon, K., Wallace, E., & van Hengstum, P. J. Historically unprecedented Northern Gulf of Mexico hurricane activity from 650 to 1250 CE. Scientific Reports, 10(1), (2020): 19092. doi:10.1038/s41598-020-75874-0.Hurricane Michael (2018) was the first Category 5 storm on record to make landfall on the Florida panhandle since at least 1851 CE (Common Era), and it resulted in the loss of 59 lives and $25 billion in damages across the southeastern U.S. This event placed a spotlight on recent intense (exceeding Category 4 or 5 on the Saffir-Simpson Hurricane Wind Scale) hurricane landfalls, prompting questions about the natural range in variability of hurricane activity that the instrumental record is too short to address. Of particular interest is determining whether the frequency of recent intense hurricane landfalls in the northern Gulf of Mexico (GOM) is within or outside the natural range of intense hurricane activity prior to 1851 CE. In this study, we identify intense hurricane landfalls in northwest Florida during the past 2000 years based on coarse anomaly event detection from two coastal lacustrine sediment archives. We identified a historically unprecedented period of heightened storm activity common to four Florida panhandle localities from 650 to 1250 CE and a shift to a relatively quiescent storm climate in the GOM spanning the past six centuries. Our study provides long-term context for events like Hurricane Michael and suggests that the observational period 1851 CE to present may underrepresent the natural range in landfalling hurricane activity.Funding for this project was provided by the Strategic Environmental Research and Development Program (SERDP) grant and NSF awards 0903020, 1902463, and 1854980 awarded to Jeffrey Donnelly, and the USGS Land Change Science Program

The Palomar Testbed Interferometer

The Palomar Testbed Interferometer (PTI) is a long-baseline infrared interferometer located at Palomar Observatory, California. It was built as a testbed for interferometric techniques applicable to the Keck Interferometer. First fringes were obtained in July 1995. PTI implements a dual-star architecture, tracking two stars simultaneously for phase referencing and narrow-angle astrometry. The three fixed 40-cm apertures can be combined pair-wise to provide baselines to 110 m. The interferometer actively tracks the white-light fringe using an array detector at 2.2 um and active delay lines with a range of +/- 38 m. Laser metrology of the delay lines allows for servo control, and laser metrology of the complete optical path enables narrow-angle astrometric measurements. The instrument is highly automated, using a multiprocessing computer system for instrument control and sequencing.Comment: ApJ in Press (Jan 99) Fig 1 available from http://huey.jpl.nasa.gov/~bode/ptiPicture.html, revised duging copy edi

Accelerated in vivo proliferation of memory phenotype CD4+ T-cells in human HIV-1 infection irrespective of viral chemokine co-receptor tropism.

CD4(+) T-cell loss is the hallmark of HIV-1 infection. CD4 counts fall more rapidly in advanced disease when CCR5-tropic viral strains tend to be replaced by X4-tropic viruses. We hypothesized: (i) that the early dominance of CCR5-tropic viruses results from faster turnover rates of CCR5(+) cells, and (ii) that X4-tropic strains exert greater pathogenicity by preferentially increasing turnover rates within the CXCR4(+) compartment. To test these hypotheses we measured in vivo turnover rates of CD4(+) T-cell subpopulations sorted by chemokine receptor expression, using in vivo deuterium-glucose labeling. Deuterium enrichment was modeled to derive in vivo proliferation (p) and disappearance (d*) rates which were related to viral tropism data. 13 healthy controls and 13 treatment-naive HIV-1-infected subjects (CD4 143-569 cells/ul) participated. CCR5-expression defined a CD4(+) subpopulation of predominantly CD45R0(+) memory cells with accelerated in vivo proliferation (p = 2.50 vs 1.60%/d, CCR5(+) vs CCR5(-); healthy controls; P<0.01). Conversely, CXCR4 expression defined CD4(+) T-cells (predominantly CD45RA(+) naive cells) with low turnover rates. The dominant effect of HIV infection was accelerated turnover of CCR5(+)CD45R0(+)CD4(+) memory T-cells (p = 5.16 vs 2.50%/d, HIV vs controls; P<0.05), naïve cells being relatively unaffected. Similar patterns were observed whether the dominant circulating HIV-1 strain was R5-tropic (n = 9) or X4-tropic (n = 4). Although numbers were small, X4-tropic viruses did not appear to specifically drive turnover of CXCR4-expressing cells (p = 0.54 vs 0.72 vs 0.44%/d in control, R5-tropic, and X4-tropic groups respectively). Our data are most consistent with models in which CD4(+) T-cell loss is primarily driven by non-specific immune activation

The Visual Orbit of 64 Piscum

We report on the determination of the visual orbit of the double-lined spectroscopic binary system 64 Piscum with data obtained by the Palomar Testbed Interferometer in 1997 and 1998. 64 Psc is a nearly equal-mass double-lined binary system whose spectroscopic orbit is well known. We have estimated the visual orbit of 64 Psc from our interferometric visibility data. Our 64 Psc orbit is in good agreement with the spectroscopic results, and the physical parameters implied by a combined fit to our interferometric visibility data and radial velocity data of Duquennoy and Mayor result in precise component masses that agree well with their spectral type identifications. In particular, the orbital parallax of the system is determined to be 43.29 \pm 0.46 mas, and masses of the two components are determined to be 1.223 \pm 0.021 M_{\sun} and 1.170 \pm 0.018 M_{\sun}, respectively. Nadal et al. put forward arguments of temporal variability in some of the orbital elements of 64 Psc, presumably explained by an undetected component in the system. While our visibility data does not favor the Nadal temporal variability inference, neither is it definitive in excluding it. Consequently we have performed both high dynamic-range near-infrared imaging and spectroscopy of potential additional companions to the 64 Psc system. Our imaging and spectroscopic data do not support the conjecture of an additional component to 64 Psc, but we did identify a faint object with unusual red colors and spectra.Comment: ApJ In Pres

A participant-led programme for field veterinary training to identify bacteriological quality of milk from the farmer to the retail outlet

The training of field veterinarians in veterinary public health needs an in-depth understanding of the in-situ problems, social and economic barriers that prevent problem solving and a relevant pedagogical approach to suit the mature learner. A participatory approach is necessary to develop such training. A course designed on the principles of adult learning theory and utilizing the experience of the field veterinarian's local knowledge combined with the expertise of the training provider can be very effective. Forty-eight field veterinarians were trained using a collaborative, participatory approach to understand the issues in clean milk production in Sri Lanka. The veterinarians developed a Hazard Analysis Critical Control Point-based decision framework to identify and evaluate the evidence of bacterial contamination points in the milk chain from the farm to the processing plant. Samples and swabs were collected for bacterial culture and results showed high bacterial counts that showed contamination of milk starting from the farm, through milk collection and chilling centers ending with 2 × 106–3 × 107 bacteria per ml of milk. Chemical and physical hazards were also identified. Lack of appropriate hygienic procedures, chilling at the farm and at the collection center, together with the delays at the chilling center was identified as main contributing factors for high bacterial counts. This problem-based training approach facilitated collaborative inquiry, experiential learning and critical analytical skills. The training enabled the veterinarians to understand the scale of the problem and how they can intervene directly and indirectly to ensure clean milk production in Sri Lanka