Effects of density dependence on diel vertical migration of populations of northern krill: a genetic algorithm model

first_imgNet and acoustic studies of diel vertical migration (DVM) in krill often show a degree of dispersion around the mean population depth, which becomes greater during night-time. Trade-off models can predict optimum depths over diet cycles but rarely explain why there is vertical scatter and why aggregations disperse at certain times. We examined density-dependent factors as a potential explanation for these phenomena. A Genetic Algorithm model was developed that predicted DVM,in a krill population based on internal state (i.e. levels of energy reserves), risk of predation and location of conspecifics. The modelling approach was designed to be dynamic in that optimal policies could respond to changing circumstances through time. Parameterisation of the model was achieved through measurements made in the Clyde Sea Area on northern krill Meganyctiphanes norvegica and its environment. Light intensity at depth was used to assess the level of risk of visual predation. Food provision was a mixture of vertically stratified phytoplankton and vertically migrating copepods. A negative exponential function was used to simulate density dependence in the food returns at each depth. Sensitivity analyses involved alterations to the level of density dependence and the metabolic rate. DVM was predicted in all sensitivity analyses and each correlated positively with net catch and acoustic observations. Increased density dependence in feeding success did not affect the mean depths chosen at night but did increase the spread of the population. The closest fit to observations was achieved when the metabolic rate was lowered and risk of mortality rate was assessed over a yearly rather than daily period. The model predicted that the population should spread more under low food conditions. We recommend that density-dependent factors be included in future state-dependent models predicting krill behaviour and life-cycle patterns.last_img read more

Haws’ late 3 helps BYU hold off Santa Clara 80-74

first_img Associated Press January 12, 2019 /Sports News – Local Haws’ late 3 helps BYU hold off Santa Clara 80-74 BYU never trailed and had its largest lead of the second half at 51-39. The Broncos (10-8, 2-2) steadily edged closer and got the deficit down to three before Haws’ dagger 3-pointer. Written by Trey Wertz had 20 points to lead Santa Clara. Keshawn Justice scored all of his career-high 17 points in the second half, Josip Vrankic had 16 points and 10 rebounds, and Tahj Eaddy added 10. Haws’ catch-and-shoot 3 from the right wing made it 77-71 with 1:33 left in the game. The Cougars (11-8, 3-1 West Coast Conference) made 3 of 4 free throws to secure the win. Haws handed out a career-high-tying eight assists and Luke Worthington added a season-high 13 points for the Cougars. Childs tied a career best with three 3-pointers. FacebookTwitterLinkedInEmailPROVO, Utah (AP) — Yoeli Childs had 27 points, TJ Haws added 16 points with a key 3-pointer late, and BYU beat Santa Clara 80-74 on Saturday night. Tags: BYU Cougars Basketball/TJ Haws/WCClast_img read more

Mrs. Joy (Napier) Hazeldean

first_imgMrs. Joy (Napier) Hazeldean, age 88, of Vevay, Indiana, entered this life on October 6, 1929, in Rising Sun, Indiana, the loving daughter of the late, Walter and Ethel (Kilburn) Napier. At the young age of nine, Joy’s mother passed away. Joy moved in with her uncle and aunt, Bill and Abby Detmer in Rising Sun, Indiana. She was raised in Rising Sun, Indiana where she attended high school. Joy was united in marriage on February 12, 1947, at the First Reform Church in Rising Sun, Indiana, to Eldric Edward Hazeldean and to this union arrived three sons, Eddie, Howard and Jerry and a daughter, Mary Lou to bless their home. Joy and Eldric shared 68 loving years of marriage together until Eldric passed away on August 5, 2015. Joy was a member of the Markland Baptist Church in Markland, Indiana. After moving to Madison, Indiana in August 2011, Joy and Eldric attended the North Madison Baptist Church. After the passing of her husband, Joy moved back to the Switzerland County community to be closer to her children where she resided until her passing. Joy was a wonderful homemaker and enjoyed cooking and caring for her children. Joy passed away at 3:10 pm, Sunday, January 14, 2018, at the King’s Daughters’ Hospital in Madison, Indiana.Joy will be missed by her sons, William “Eddie” Hazeldean of Midlothian, TX and Eldric Howard Hazeldean and his wife: Julia of Vevay, IN; her daughter, Mary Lou Griffin and her husband: Ronnie of Pleasant, IN; her daughter-in-law, Janice Hazeldean of Vevay, IN; her grandchildren, Kelli Brockman and her husband: Donald of Vevay, IN, Kevin Scudder and his wife: Jill of Convoy, OH, Abbye Hazeldean of Dallas, TX, Joshua Hazeldean and his wife: Megan of Kaneohe, HI and Jillian Hazeldean of San Diego, CA; her great-grandchildren, Bryant, Briann, Carter and Sophie; her step-great-grandchildren, Liliana and Abbigail Dietrich; her sister-in-law, Mildred Schuster of Battle Creek, MI and her several nieces and nephews.She was preceded in death by her parents, Walter and Ethel (Kilburn) Napier; her uncle and aunt that raised her since the age of 9, Bill and Abby Detmer; her son, Jerome Lee “Jerry” Hazeldean, died July 20, 2011; her daughter-in-law, Elaine Hazeldean, died November 10, 2017; her granddaughter, Kimberly Ann Hazeldean, died July 11, 1982; her sister, Blanche Bennett, died July 18, 2015 and her sister-in-law, Evelyn Felker, died September 6, 2014.Funeral services will be conducted Saturday, January 20, 2018, at 11:00 am, by Pastor Bobby Brundige Jr. at the Haskell & Morrison Funeral Home, 208 Ferry Street Vevay, Indiana 47043. Interment will follow in the Vevay Cemetery, Vevay, Indiana.Friends may call 5:00 pm – 8:00 pm, Friday, January 19, 2018, at the Haskell & Morrison Funeral Home, 208 Ferry Street Vevay, Indiana 47043. Memorial contributions may be made to Markland Baptist Church. Cards are available at the funeral home.last_img read more