Calving Giant Icebergs: Old Principles, New Applications

Earth-orbiting satellites can now monitor calving of large icebergs from ice shelves bordering the marine West Antarctic Ice Sheet, and recent calving events have stimulated interest in calving mechanisms. To advance this interest pioneering work in brittle and ductile fracture mechanics is reviewed, leading to a new application to calving of giant icebergs from Antarctic ice shelves. The aim is to view iceberg calving as more than terminal events for Antarctic ice when glaciologists lose interest. Instead calving launches Antarctic ice into the larger dynamic system of Earth\u27s climate machine. This encourages a holistic approach to glaciology

Basal Melting Along the Floating Part of Byrd Glacier

A mass balance calculation was made for the floating part of Byrd Glacier, using 1978-79 ice elevation and velocity data, over the 45 km of Byrd Glacier from its grounding line to where it leaves its fjord and merges with the Ross Ice Shelf. Smoothed basal melting rates were relatively uniform over this distance and averaged 12 +/- 2 m yr(-1)

Fracture and Back Stress Along the Byrd Glacier Flowband on the Ross Ice Shelf

East Antarctic ice discharged by Byrd Glacier continues as a flowband to the calving front of the Ross Ice Shelf. Flow across the grounding line changes from compressive to extensive as it leaves the fjord through the Transantarctic Mountains occupied by Byrd Glacier. Magnitudes of the longitudinal compressive stress that suppress opening of transverse tensile cracks are calculated for the flowband. As compressive back stresses diminish, initial depths and subsequent growth of these cracks, and their spacing, are calculated using theories of elastic and ductile fracture mechanics. Cracks are initially about one millimeter wide, with approximately 30 in depths and 20 in spacings for a back stress of 83 kPa at a distance of 50 kin beyond the fjord, where floating ice is 600 in thick. When these crevasses penetrate the whole ice thickness, they release tabular icebergs 20 kin to 100 kin wide, spaced parallel to the calving front of the Ross Ice Shel

Relating Crevassing to Non-Linear Strain in the Floating Part of Jakobshavn Isbrae, West Greenland

Jakobshavn Isbrae is a major ice stream that drains the west-central Greenland ice sheet and becomes afloat in Jakobshavn Isfiord (69degreesN, 49degreesW), where it has maintained the world\u27s fastest-known sustained velocity and calving rate (7 km a(-1)) for at least four decades. The floating portion is approximately 12 km long and 6 km wide. Surface elevations and motion vectors were determined photogrammetrically for about 500 crevasses on the floating ice, and adjacent grounded ice, using aerial photographs obtained 2 weeks apart in July 1985. Surface strain rates were computed from a mesh of 399 quadrilateral elements having velocity measurements at each corner. It is shown that heavy crevassing of floating ice invalidates the assumptions of linear strain theory that (i) surface strain in the floating ice is homogeneous in both space and time, (ii) the squares and products of strain components are nil, and (iii) first- and second-order rotation components are small compared to strain components. Therefore, strain rates and rotation rates were also computed using non-linear strain theory. The percentage difference between computed linear and non-linear second invariants of strain rate per element were greatest (mostly in the range 40-70%) where crevassing is greatest. Isopleths of strain rate parallel and transverse to flow and elevation isopleths relate crevassing to known and inferred pinning points

2007 Inventory of Radiochemistry Detector Elements and Compounds

Since the last report, there have been no material changes in the detector element inventories in buildings 151 and 332 at LLNL. Stable element inventories in building 151 have remained stable since the inventory in September 2005. For the first time in many years, Stockpile Radiochemistry personnel viewed radioactive tracer materials that reside in building 332. A list of LLNL tracers and locations are available under separate cover. Despite the recent NNSA agreement to retain 2.8 kg of {sup 233}U for programmatic purposes, we have yet to identify a location that is appropriate and will accept the material. A recent visit to the Oak Ridge National Laboratory (ORNL) in September 2006 revealed nearly 190 kg of material with very high {sup 233}U content scheduled for down-blending in various chemical and isotopic forms. The chemical form, isotopic and chemical purities of this material were such that roughly 150 kg of the material was of comparable composition to the desired tracer package material and would be acceptable for use in an underground test, should the US even conduct such a test. Efforts continue to remove 2.8 kg of material from the down-blend cue and reserve it for the Test Readiness mission

The effect of exogenous glucose infusion on early embryonic development in lactating dairy cows

peer-reviewedThe objective of this study was to examine the effect of intravenous infusion of glucose on early embryonic development in lactating dairy cows. Nonpregnant, lactating dairy cows (n = 12) were enrolled in the study (276 ± 17 d in milk). On d 7 after a synchronized estrus, cows were randomly assigned to receive an intravenous infusion of either 750 g/d of exogenous glucose (GLUC; 78 mL/h of 40% glucose wt/vol) or saline (CTRL; 78 mL/h of 0.9% saline solution). The infusion period lasted 7 d and cows were confined to metabolism stalls for the duration of the study. Coincident with the commencement of the infusion on d 7 after estrus, 15 in vitro-produced grade 1 blastocysts were transferred into the uterine horn ipsilateral to the corpus luteum. All animals were slaughtered on d 14 to recover conceptuses, uterine fluid, and endometrial tissue. Glucose infusion increased circulating glucose concentrations (4.70 ± 0.12 vs. 4.15 ± 0.12 mmol/L) but did not affect milk production or dry matter intake. Circulating β-hydroxybutyrate concentrations were decreased (0.51 ± 0.01 vs. 0.70 ± 0.01 mmol/L for GLUC vs. CTRL, respectively) but plasma fatty acids, progesterone, and insulin concentrations were unaffected by treatment. Treatment did not affect either uterine lumen fluid glucose concentration or the mRNA abundance of specific glucose transporters in the endometrium. Mean conceptus length, width, and area on d 14 were reduced in the GLUC treatment compared with the CTRL treatment. A greater proportion of embryos in the CTRL group had elongated to all length cut-off measurements between 11 and 20 mm (measured in 1-mm increments) compared with the GLUC treatment. In conclusion, infusion of glucose into lactating dairy cows from d 7 to d 14 post-estrus during the critical period of conceptus elongation had an adverse impact on early embryonic development

Purdue College of Pharmacy Experience with Blood Pressure Screenings at the Indiana State Fair

The objective of this community outreach initiative is to develop and implement a student-led blood pressure screening at the Indiana State Fair in conjunction with the Purdue College of Pharmacy and the Hook’s Drug Store Museum. Under the mentorship of two pharmacy faculty members, third- and fourth-year professional PharmD students and pharmacy fellows hold a nine-hour blood pressure screening at the Indiana State Fair each year. The screening is held at the Hook’s Drug Store Museum and the students and fellows sign-up in teams of 3-4 to host the event. Fair-goers visiting the screening have their blood pressure taken using automated blood pressure devices and the readings are recorded into one of three categories: ≤140 mmHg/≤90 mmHg, \u3e140 mmHg/\u3e90 mmHg, or \u3e150 mmHg/\u3e100 mmHg. All patients receive a card with their blood pressure reading, are counseled on hypertension management and possible health complications, and receive a sticker that reads “I had my blood pressure checked at the Indiana State Fair/Purdue College of Pharmacy.” Students complete a reflection following their involvement. Data from the last five years was analyzed. Over the five years, a total of 838 fairgoers have utilized the opportunity to have their blood pressure checked. In addition, 50 pharmacy students, two fellows, and two faculty members have participated in hosting the screening. There has been growing involvement over the years, with 213 individuals visiting the booth in 2019. There has been a steady increase in the percentage of patients with a blood pressure reading in the lowest category. Participation in the Indiana State Fair has become a tradition for the College of Pharmacy as students enjoy and are grateful for such learning opportunities. This initiative allows students to develop and apply their clinical knowledge and communication skills while improving health and awareness of community members

The determinants of vulnerability to currency crises: country-specific factors versus regional factors

We investigate the determinants of exchange market pressures (EMP) for some new EU member states at both the national and regional levels, where macroeconomic and financial variables are considered as potential sources. The regional common factors are extracted from these variables by using dynamic factor analysis. The linear empirical analysis, in general, highlights the importance of country-specific factors to defend themselves against vulnerability in their external sectors. Yet, given a significant impact of the common component in credit on EMP, a contagion effect is apparent through the conduit of credit market integration across these countries under investigation

Associations between postpartum phenotypes, cow factors, genetic traits, and reproductive performance in seasonal-calving, pasture-based lactating dairy cows

peer-reviewedThe objective of this study was to evaluate associations between corpus luteum (CL) status, uterine health, body condition score (BCS), metabolic status, parity, genetic merit for fertility traits, and reproductive performance in pasture-based dairy cows managed for seasonal reproduction. First- and second-lactation (n = 2,600) spring-calving dairy cows from 35 dairy farms located in Ireland were enrolled in the study. Farms were visited every 2 wk, and animals that were at wk 3 (range: 14–27 d in milk) and wk 7 (range: 42–55 d in milk) postpartum were examined. Body condition score was measured using a 1-to-5 scale in 0.25-point increments. Transrectal ultrasound examination was performed at wk 3 and 7 postpartum to determine presence or absence of CL and ultrasound reproductive tract score (scale of G1–G4). Blood samples were collected at each visit, and the concentrations of glucose, β-hydroxybutyrate (BHB), and fatty acids (FA) were analyzed using enzymatic colorimetry. Animals were grouped into 3 BCS categories [low (≤2.5), target (2.75–3.25), and high (≥3.5)], 2 CL categories (present or absent), 2 uterine health status categories (normal or abnormal), and 3 metabolic status categories [good (high glucose, low FA and BHB), poor (low glucose, high FA and BHB), and moderate (all other combinations)]. Fisher's exact test was used to test for associations between variables and was supplemented by logistic regression. More cows with a CL at wk 7 were served during the first 21 d of the breeding period compared with cows without a CL. Cows classified as having a uterine score of G3 or G4 at wk 3 and 7 had lower odds of pregnancy establishment during the breeding period compared with animals with a uterine score of G1 or G2. Animals with low BCS at wk 7 had lower odds of pregnancy establishment than cows with a target BCS. Cows classified as having good metabolic status at both wk 3 and wk 7 had greater odds of pregnancy establishment during the first 21 d of the breeding season than those classified as having poor metabolic status. Overall, primiparous cows had greater reproductive performance than second-parity cows. Animals in the quartiles with the best predicted transmitting ability for survival and calving interval had better reproductive performance compared with animals in the other quartiles. Cows that had better genetic merit for fertility traits and good metabolic status, achieved target BCS, and had a favorable ultrasound reproductive tract score and a CL present at wk 7 postpartum had superior reproductive performance

The relationship between anogenital distance and fertility, and genome-wide associations for anogenital distance in Irish Holstein-Friesian cows

peer-reviewedThe evaluation of anogenital distance (AGD), the distance from the center of the anus to base of the clitoris, as a potential fertility trait for genetic selection in dairy cows has generated recent interest. The objectives of this cross-sectional observational study were to (1) characterize the distribution and variability of AGD, (2) determine factors associated with AGD, (3) estimate heritability for AGD, (4) identify single nucleotide polymorphisms (SNP) associated with phenotypic variation of AGD, and (5) validate the relationship between categories of AGD and fertility in Irish Holstein-Friesian cows. Anogenital distance was measured using digital calipers in 1,180 Holstein cows (mean ± standard deviation: 225 ± 79 d in milk) from 10 dairy herds located in Munster, Ireland. In addition, age (yr), weight (kg), height at hip (cm), and body condition score (BCS) at the time of AGD measurement were determined in a subset of 281 cows. Genotype information available from 908 cows was subsequently imputed to the Illumina Bovine High Density BeadChip (Illumina Inc., San Diego, CA) for genome-wide association analysis of phenotypic variation in AGD. Overall, AGD had a normal distribution and high variability (mean ± standard deviation; 119.2 ± 11.6 mm). Anogenital distance was weakly but positively associated with cow age, hip height, and body weight, and negatively associated with BCS; the phenotypic variation in AGD that was explainable by these variables was small (coefficient of determination; R2 = 0.09, 0.06, 0.10, and 0.02, respectively). The estimated heritability for AGD was 0.37 (standard error of mean ± 0.08). Six SNP of suggestive significance were identified on Bos taurus autosomes 6, 15, 20, and 26; however, none of these SNP was related to previously identified candidate genes for fertility. Cows were categorized into quartiles (Q1; 86 to 111 mm; n = 311, Q2; 112 to 120 mm; n = 330; Q3; 121 to 127 mm; n = 265, and Q4; 128 to 160 mm; n = 274) based on AGD and the association with reproductive outcomes examined (21-d submission rate, pregnancy to first AI, pregnancy rate within 21, 42 and 84-d after the farm mating start date, and number of times bred). None of the reproductive variables differed significantly between AGD categories. In summary, despite identification of high variability and moderate heritability for AGD in Irish Holstein-Friesian cows, reproductive outcomes did not differ between categories of AGD. This latter result differs from our previous finding of an inverse relationship between AGD and pregnancy outcomes in first- and second-parity Canadian Holstein cows, emphasizing the need to test and validate this new phenotype in diverse cow populations