Density Driven Turbulent Mixing at Batch Interfaces

Models are developed for the turbulent mixing and growth at a batch interface. These models depend crucially on the choice of diffusion coefficient $D$. The model where $D$ is the harmonic average of the mixing coefficients of the two pure fluids is analysed in detail, since this is likely to be a good approximation when the density difference between the two fluids is small. When the density difference is large, the laminar flow regime fingering will occur and there will be a relatively sharp interface between the fluids. However, in the turbulent case, as gravity drives the denser fluid into the less dense one the invading fluid is immediately mixed by turbulent diffusion. This means that sharp interfaces do not exist. Instead there will be a finite mixing region where the volume fraction of each fluid changes from $0$ to $1$. In this case $D$ will depend upon the relative concentration of the fluids. This approach leads to a degenerate diffusion problem

Nanomatemàtiques: modelització matemàtica a la nanoescala

En aquest article exposem tres problemes estudiats recentment al grup de Matemàtica Industrial del Centre de Recerca Matemàtica, en els quals l'aproximació del continu resulta vàlida per a descriure fenòmens a la nanoescala: 1. Transferència de calor en nanofluids: els resultats experimentals que confirmen l'increment de la capacitat de transferir calor dels nanofluids respecte dels fluids estàndard són sovint contradictoris. Mitjançant una anàlisi de capa límit mostrarem com el model matemàtic utilitzat en nombroses ocasions per justificar l'increment en la transferència de calor dels nanofluids preveu, de fet, una disminució d'aquesta propietat. 2. Fusió de nanopartícules: les nanopartícules mostren un increment abrupte de la velocitat de transició de fase a mesura que el seu radi decreix. Presentarem un model matemàtic que descriu aquest fenomen. El model preveu temps totals de transició sòlid-líquid que concorden amb les observacions experimentals. 3. Increment del flux d'un fluid en nanotubs de carboni (CNT): mostrarem que els resultats experimentals sobre l'increment de flux en nanotubs de carboni es poden explicar mitjançant les equacions estàndard de la dinàmica de fluids amb la incorporació d'una capa d'extinció (depletion layer) a la interfície entre el fluid i el sòlid.In this paper we discuss three problems recently studied within the Industrial Maths Research Group at the Centre de Recerca Matemàtica, where continuum theory may be applied to describe nanoscale phenomena: 1. Heat transfer with nanofluids: Experimental results concerning the remarkable heat transfer characteristics of nanofluids are at times contradictory. We apply a boundary layer analysis to show that a standard model which has been used by many authors to predict an improvement in heat transfer with increasing nanoparticle concentration in fact shows a decrease. 2. Nanoparticle melting: Nanoparticles often exhibit a sharp increase in melting rate as the size decreases. A mathematical model will be presented which predicts this phenomena and explains the experimentally observed abrupt melting of the smallest nanoparticles. 3. Enhanced flow in carbon nanotubes (CNTs): This model shows that the experimentally observed enhancement can be explained using standard flow equations but with a depletion layer between the liquid and solid interfaces. The results also provide one physical explanation for the Navierslip condition

Sentinels in Salmon Aquaculture: Heart Rates Across Seasons and During Crowding Events

Advances in tag technology now make it possible to monitor the behavior of small groups of individual fish as bioindicators of population wellbeing in commercial aquaculture settings. For example, tags may detect unusual patterns in fish heart rate, which could serve as an early indicator of whether fish health or welfare is becoming compromised. Here, we investigated the use of commercially available heart rate biologgers implanted into 24 Atlantic salmon weighing 3.6 ± 0.8 kg (mean ± SD) to monitor fish over 5 months in a standard 12 m × 12 m square sea cage containing ∼6,000 conspecifics. Post tagging, fish established a diurnal heart rate rhythm within 24 h, which stabilized after 4 days. Whilst the registered tagged fish mortality over the trial period was 0%, only 75% of tagged fish were recaptured at harvest, resulting in an unexplained tag loss rate of 25%. After 5 months, tagged fish were approximately 20% lighter and 8% shorter, but of the similar condition when compared to untagged fish. Distinct diurnal heart rate patterns were observed and changed with seasonal day length of natural illumination. Fish exhibited lower heart rates at night [winter 39 ± 0.2 beats per min (bpm), spring 37 ± 0.2 bpm, summer 43 ± 0.3 bpm, mean ± SE] than during the day (winter 50 ± 0.3 bpm, spring 48 ± 0.2 bpm, summer 49 ± 0.2 bpm) with the difference between night and day heart rates near half during the summer (6 bpm) compared to winter and spring (both 11 bpm). When fish experienced moderate and severe crowding events in early summer, the highest hourly heart rates reached 60 ± 2.5 bpm and 72 ± 2.4 bpm, respectively, on the day of crowding. Here, if the negative sublethal effects on fish that carry tags (e.g., growth rate) can be substantially reduced, the ability to monitor diurnal heart rate patterns across seasons and detect changes during crowding events, and using heart rate biologgers could be a useful warning mechanism for detecting sudden changes in fish behavior in sea cages.publishedVersio

Cardiovascular Service Line Chaplain at an Academic Medical Center: Creation, Implementation, and Establishment

Problem Statement: As health care providers and organizations have become complex and specialized, efforts to address the spiritual needs of patients and care team members are often absent. Background: Medical advances, life-saving treatments, and increased efficiency of patient care have all come at a cost to patients and health care providers. We appropriately measure our care team’s performance with disease- and procedure-specific data on morbidity and mortality. However, these measurements come at the risk of rewriting Hippocrates’ endeavor from “cure sometimes, relieve often, comfort always” to “cure always.” The suggestion that failure is not an option is an unattainable expectation with a high price, namely the spiritual distress of care team members, patients, and their families. In 2018, The Joint Commission addressed the issue of unmet spiritual needs, stating that these needs can be associated with greater emotional distress, pain, and anxiety; higher medical care costs; and poorer quality of life. Application: In 2015, the cardiovascular service line at an academic medical center implemented a spiritual care provider position to address the unmet spiritual needs of patients and care team staff. In this article, we describe (1) the evolution of the spiritual care provider’s role and (2) the impact of this resource on the healing of patients and as a support for the personal and professional well-being of health care providers

Cover crops in Missouri : putting them to work on your farm (2016)

New 8/15; Link updates 4/16/Web

Detecting and tracing farmed salmon with natural geo-element otolith ‘fingerprint’ tags: developing and validating tag delivery techniques

Farmed fish escape and enter the environment with possible effects on wild populations. Attempts to reduce the incidence of escape could be assisted if individuals can be traced back to the point of escape, so that escape causes can be identified and technical standards improved. We tested if permanent marks could be created on the otoliths of salmon that could be detected throughout the lives of the fish. Marks were created by altering the natural ratios of the natural elements barium (Ba) and strontium (Sr) in the otolith. By combining several natural geo-elements, unique fingerprints can be created, which can act as codes that enable tracing of fish back to the point of escape. The marks are detected by laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). We delivered marks to salmon in 4 different ways: 1) injecting female broodstock with geo-element markers prior to spawning so that the marks can be passed from the mother to all eggs in a clutch, with all larvae receiving a mark in the core of their otolith; 2) incorporating small amounts of geo-element markers into the vaccination serum for co-delivery of the marks into the fish along with the vaccine; 3) bathing eggs of salmon in geo-element solution immediately after fertilisation; and 4) bathing late stage yolk-sac larvae in an geo-element solution. All methods were successful in creating unique, permanent marks on the otoliths of salmon that could be detected throughout the lifetime of the fish. For all four delivery techniques, marking was 100% successful with Ba at concentrations as low as 0.001 μg. g-1 fish and for Sr at 1 μg. g-1 fish. Detection limits with the laser were set at 99.94%, so the techniques delivered a very high degree of accuracy. In all methods, we developed procedures that minimized marking and analysis costs, so that methods could be implemented at full-scale commercial application. After marking, fish were ongrown under standard commercial conditions to harvest size (approx. 4 kg). Marking methods had no effect on all standard production parameters, such as survival, growth, and the incidence of larval deformities compared to unmarked control fish. Further, the amounts of natural 2 strontium and barium used to create the marks are so small that they pose no problem for food safety, as they represent less than 0.1–1% of the amounts that naturally occur in salmon tissues. Our results indicate single marking with one of the techniques can create up to 63 unique fingerprint marks at low cost using Ba (0.0002–0.02 $US per mark) and Sr (0.46–0.82$US per mark). Double marking in different parts of the otolith using two of the different code delivery methods was also successful (e.g. maternal transfer and vaccination combined). This means 63 x 15 unique codes, or 1023 codes are possible, which is sufficient to provide a unique code for every site in the sea in Norway. We conclude that fingerprinting with natural geo-elements is feasible for commercial application. 94% of the salmon in Norway could be marked for as little as 0.02 $US per fish with a single marking method with traceability back to the top 63 producing companies. Double marking would enable more detailed tracing of every fish back to its site in the sea.Oppdrettslaks rømmer og kan påvirke de ville populasjonene. Antallet rømminger kunne vært redusert hvis den rømte fisken kunne vært sporet tilbake til rømningsstedet slik at årsaken til rømning kunne blitt identifisert. Vi testet om det er mulig å lage kjemiske merker på laksens ørestein som kan identifiseres gjennom hele livssyklusen. Disse merkene ble laget ved å endre forholdet mellom naturlige geoelementer (stabile isotoper av barium (Ba) og strontium (Sr)) i øresteinen. Ved å kombinere flere av disse naturlige geoelementene kan en lage unike ’fingeravtrykk/strekkoder’ som kan brukes for å spore en fisk tilbake til rømningsstedet. Merkene leses ved en teknikk hvor en brenner hull i øresteinen med laser og måler sammensetningen ved hjelp av massespektrometri. Merkene i øresteinen ble etablert ved hjelp av fire metoder: 1) ved å injisere morfisken med geoelementer i forkant av gytingen slik at disse kan overføres til alle eggene og at merket blir avsatt i øresteinens kjerne; 2) ved å tilsette små mengder av geoelementene i fiskens vaksine slik at fisken merkes ved vaksineringen; 3) ved å tilsette geoelementer i svellevannet som tilsettes rett etter befruktningen av eggene; 4) ved å bade plommesekkyngelen i en løsning med geoelementer. Ved alle metodene klarte vi å lage unike, permanente merker i øresteinen som kunne finnes og kjennes igjen gjennom hele fiskens livssyklus. Alle metodene ga 100 Etter merking ble fisken oppdrettet under standard oppdrettsbetingelser til slaktestørrelse (ca. 4 kg). Merkemetodene påvirket ingen produksjonsparametre som overlevelse, vekst eller innslag av deformiteter. Mengden naturlig strontium og barium som ble brukt er mindre enn 1 Våre resultater viser at en ved enkel merking med en av teknikkene kan lage opptil 63 unike ‘fingeravtrykk’ til en lav kostnad ved bruk av Ba (0,0002–0,02$US per merke) og Sr (0,46–0,82 $US per 3 merke). Dobbelmerking; dvs. å merke i ulike deler av øresteinen ved hjelp av to av metodene, var også mulig (for eksempel injeksjon av morfisk og vaksinering på parrstadiet). Dette betyr at en kan lage 63 x 15 = 1023 unike koder, nok til å gi hver lokalitet i Norge en unik kode. Vi konkluderer med at merking med naturlige geoelementer er en mulig løsning for å merke oppdrettsfisk. 94$US per fisk og med mulighet til å spore den tilbake til de 63 største produsentene. Dobbelmerking gir mulighet for sporing tilbake til lokalitet

Increasing Ball Velocity in the Overhead Athlete: A Meta-Analysis of Randomized Controlled Trials

Overhead athletes routinely search for ways to improve sport performance, and one component of performance is ball velocity. The purpose of this meta-analysis was to investigate the effect of different strengthening interventions on ball and serve velocity. A comprehensive literature search with pre-set inclusion and exclusion criteria from 1970 to 2014 was conducted. Eligible studies were randomized control trials including the mean and SDs of both pretest and posttest ball velocities in both the experimental and the control groups. The outcome of interest was ball/serve velocity in baseball, tennis, or softball athletes. Level 2 evidence or higher was investigated to determine the effect different training interventions had on velocity. Pretest and posttest data were extracted to calculate Hedges\u27s g effect sizes with 95% confidence intervals (CIs). Methodological qualities of the final 13 articles within the analysis were assessed using the Physiotherapy Evidence Database scale. The majority of the articles included in this analysis had an effect on velocity with the strongest effect sizes found in periodized training (Hedges\u27s g = 3.445; 95% CI = 1.976-4.914). Six studies had CI that crossed zero, indicating that those specific interventions should be interpreted with caution. Consistent and high-quality evidence exists that specific resistance training interventions have an effect on velocity. These findings suggest that interventions consisting of isokinetic training, multimodal training, and periodization training are clinically beneficial at increasing velocity in the overhead athlete over different windows of time

Submerged cage aquaculture of marine fish: a review of the biological challenges and opportunities

Surface-based cages are the dominant production technology for the marine finfish aquaculture industry. However, issues such as extreme weather events, poor environmental conditions, interactions with parasites, and conflicts with other coastal users are problematic for surface-based aquaculture. Submerged cages may reduce many of these problems and commercial interest in their use has increased. However, a broad synthesis of research into the effects of submerged culture on fish is lacking. Here, we review the current status of submerged fish farming worldwide, outline the biological challenges that fish with fundamentally different buoyancy control physiologies face in submerged culture, and discuss production benefits and problems that might arise from submerged fish farming. Our findings suggest that fish with closed swim bladders, and fish without swim bladders, may be well-suited to submerged culture. However, for fish with open swim bladders, such as salmonids, submergence is more complex as they require access to surface air to refill their swim bladders and maintain buoyancy. Growth and welfare of open swim bladder fish can be compromised by submergence for long periods due to complications with buoyancy regulation, but the recent addition of underwater air domes to submerged cages can alleviate this issue. Despite this advance, a greater understanding of how to couple advantageous environmental conditions with submerged culture to improve fish growth and welfare over the commercial production cycle is required if submerged cages are to become a viable alternative to surface-based cage aquaculture.publishedVersio