Establishing climate–growth relationships for yelloweye rockfish (Sebastes ruberrimus) in the northeast Pacific using a dendrochronological approach     

BRYAN A. BLACK  GEORGE W. BOEHLERT  MARY M. YOKLAVICH 《Fisheries Oceanography》2008,17(5):368-379

We applied dendrochronology (tree‐ring) methods to develop multidecadal growth chronologies from the increment widths of yelloweye rockfish (Sebastes ruberrimus) otoliths. Chronologies were developed for the central California coast, a site just north of Vancouver Island, British Columbia, and at Bowie Seamount west of the Queen Charlotte Islands, British Columbia. At each site, synchronous growth patterns were matched among otoliths via the process of cross‐dating, ensuring that the correct calendar year was assigned to all increments. Each time series of growth‐increment measurements was divided by the values predicted by a best‐fit negative exponential function, thereby removing age‐related trends. These detrended time series were averaged into a master chronology for each site, and chronologies were correlated with monthly averages of sea surface temperatures, upwelling, the Northern Oscillation Index, and the Pacific Decadal Oscillation. The two northern growth chronologies positively correlated with indices of warm ocean conditions, especially from the prior summer through the spring of the current year. During the same period, the California chronology positively correlated with indices of cool ocean conditions, indicating an opposing productivity regime for yelloweye rockfish between the California Current and the Gulf of Alaska. Overall, this study demonstrates how tree‐ring techniques can be applied to quickly develop annually resolved chronologies and establish climate–growth relationships across various temporal and spatial scales.  相似文献   

Oceanographic investigation of the American Samoa albacore (Thunnus alalunga) habitat and longline fishing grounds   总被引：1，自引：0，他引：1  

RÉKA DOMOKOS  MICHAEL P. SEKI  JEFFREY J. POLOVINA  DONALD R. HAWN 《Fisheries Oceanography》2007,16(6):555-572

The American Samoa fishing ground is a dynamic region with strong mesoscale eddy activity and temporal variability on scales of <1 week. Seasonal and interannual variability in eddy activity, induced by baroclinic instability that is fueled by horizontal shear between the eastward‐flowing South Equatorial Counter Current (SECC) and the westward‐flowing South Equatorial Current (SEC), seems to play an important role in the performance of the longline fishery for albacore. Mesoscale eddy variability in the American Samoa Exclusive Economic Zone (EEZ) peaks from March to April, when the kinetic energy of the SECC is at its strongest. Longline albacore catch tends to be highest at the eddy edges, while albacore catch per effort (CPUE) shows intra‐annual variability with high CPUE that lags the periods of peak eddy activity by about 2 months. When CPUE is highest, the values are distributed toward the northern half of the EEZ, the region affected most by the SECC. Further indication of the possible importance of the SECC for longline performance is the significant drop in eddy variability in 2004 when compared with that observed in 2003 – resulting from a weak SECC – which was accompanied by a substantial drop in albacore CPUE rates and a lack of northward intensification of CPUE. From an ecosystem perspective, evidence to support higher micronekton biomass in the upper 200 m at eddy boundaries is inconclusive. Albacore's vertical distribution seems to be governed by the presence of prey. Albacore spend most of their time between 150 and 250 m, away from the deep daytime and shallow nighttime sonic scattering layers, at depths coinciding with those of small local maxima in micronekton biomass whose backscattering properties are consistent with those of albacore's preferred prey. Settling depths of longline sets during periods of decreased eddy activity correspond to those most occupied by albacore, possibly contributing to the lower CPUE by reducing catchability through rendering bait less attractive to albacore in the presence of prey.  相似文献   

Association of double-stranded RNA with whitefly-mediated silvering in squash     

N. BHARATHAN  W. R. GRAVES  K. R. NARAYANAN  D. J. SCHUSTER†  H. H. BRYAN  R. T. McMILLAN JR 《Plant pathology》1990,39(3):530-538

A disorder of unknown aetiology appearing as silvering on squash (Cucurbita pepo) leaves has become prevalent in south Florida. Typical symptoms, observed after 2 weeks of exposure to adults of Bemisia tabaci , the sweet potato whitefly (SPWF) include vein clearing followed by silvering of whole leaves. Fruits from affected plants are blanched or streaked longitudinally. The silverleaf syndrome was not mechanically transmissible when crude extracts of symptomatic leaves were used as inoculum. Two sizes of double-stranded RNA (dsRNA) of c. 4.6 and 4.2 kilobase pairs (kbp) were consistently observed in leaf extracts of caged, whitefly-infested, symptomatic plants. In contrast, caged plants not exposed to whiteflies showed no symptoms and contained no detectable dsRN A. In addition, squash plants exposed to SPWF colonies from California neither developed silverleaf symptoms nor contained any dsRNA. Double-stranded RNA could also be readily detected in whitefly-infested yellow summer squash and zucchini from the field. However, asymptomatic eggplant and watermelon infested with SPWF from nearby fields did not contain detectable dsRNA. Dot-spot hybridization assays using an RNA-specific probe detected homologous sequences in both adults and nymphs of SPWF that induced silverleaf symptoms but not in adults and nymphs of SPWF that could not induce silverleaf symptoms. These results, along with the non-endogenous nature of the detected dsRNA suggest that the dsRNA is or is associated with the causal agent of whitefly-mediated leaf silvering in squash.  相似文献   

Physical and biological consequences of a climate event in the central North Pacific   总被引：4，自引：0，他引：4  

JEFFREY J. POLOVINA  GARY T. MITCHUM  NICK E. GRAHAM  MITCHELL P. CRAIG  EDWARD E. DEMARTINI  ELIZABETH N. FLINT 《Fisheries Oceanography》1994,3(1):15-21

Climatic changes over the North Pacific which began in the mid 1970s, peaked in the early 1980s, and ended by the late 1980s, appear to have altered productivity at various trophic levels in the marine ecosystem in the central North Pacific. The climatic change resulted in increased mixed layer depth and the frequency of deep mixing events, particularly during January-March. A number of biological time series for species ranging from primary to apex levels in the North-western Hawaiian Islands, show corresponding declines in productivity of 30–50% from the early 1980s to the present. We hypothesize that during the early 1980s, increased mixing due to the climate event resulted in greater nutrient input into the euphotic zone and ultimately increased ecosystem productivity. Productivity over a range of trophic levels declined when the climate event ended.  相似文献   

Decadal variation in the trans-Pacific migration of northern bluefin tuna (Thunnus thynnus) coherent with climate-induced change in prey abundance     

JEFFREY J. POLOVINA 《Fisheries Oceanography》1996,5(2):114-119

Northern bluefin tuna, Thunnus thynnus, apparently spawn only in the western Pacific and a portion of the juveniles migrate to the eastern Pacific. During the past decade, catches of northern bluefin in the eastern Pacific have declined. One possible cause for this decline, proposed by bluefin stock assessment studies, is a decline in the proportion of bluefin that migrate out of the western Pacific. This hypothesis is examined with several indices of the relative abundance of bluefin tuna in the western and eastern Pacific. These indices suggest a decline in the proportion of bluefin migrating to the eastern Pacific since 1977. This period of reduced bluefin migration coincides with a period when a prey of bluefin, Japanese sardine, Sardinops melanosticta, were abundant off Japan. It is hypothesized that in years when sardines are abundant off Japan, a higher proportion of bluefin stay in the western Pacific compared with years when sardines are scarce. Currently, the adun-dance of sardines off Japan is declining. If this decline continues, this hypothesis predicts an increase in bluefin migrating north of Hawaii and into the eastern Pacific.  相似文献   

Surgical Repair of Tibial Tuberosity Avulsion Fractures in Four Horses     

BARBARA L. SMITH DVM  MS    JOERG A. AUER DrMedVet  MS  DiplomateACVS  JEFFREY P. WATKINS DVM  MS  DiplomateACVs 《Veterinary surgery : VS》1990,19(2):117-121

Four horses, 2 to 17 years old, were treated for unilateral avulsion fractures of the tibial tuberosity. Two horses were treated successfully with tension band wiring or plating in combination with lag screw fixation. One horse was euthanatized because of implant failure during recovery and one was euthanatized on day 11 because a longitudinal fracture of the tibial tuberosity occurred through the plane of the screws used for stabilization.  相似文献   

CORRELATION OF ULTRASOUND FINDINGS,LIVER AND SPLEEN CYTOLOGY,AND PROGNOSIS IN THE CLINICAL STAGING OF HIGH METASTATIC RISK CANINE MAST CELL TUMORS     

ALISON P. BOOK  JANEAN FIDEL  TAMARA WILLS  JEFFREY BRYAN  RANCE SELLON  JOHN MATTOON 《Veterinary radiology & ultrasound》2011,52(5):548-554

Cytologic sampling of the ultrasonographically normal spleen and liver is not implemented routinely in the clinical staging of canine cutaneous mast cell tumors and normal ultrasound findings are often accepted as sufficient evidence for ruling out splenic or liver metastasis. Our objective was to define the specificity and sensitivity of ultrasound findings for diagnosis of mast cell infiltration when verified with cytologic evaluation, and to define the prognostic role of cytologic evaluation of liver and splenic aspirates. Dogs with a diagnosis of clinically aggressive grade II, or grade III mast cell tumor treated with a combination vinblastine/CCNU chemotherapy protocol, were selected retrospectively based on availability of cytologic evaluation of spleen plus or minus liver for staging. Out of 19 dogs, 10 dogs had a grade II tumor and nine a grade III tumor. Seven dogs had mast cell infiltration of the spleen, liver, or both. The sensitivity of ultrasound for detecting mast cell infiltration was 43% for the spleen and 0% for the liver. Dogs with positive cytologic evidence of mast cell infiltration to spleen, liver, or both had significantly shorter survival (100 vs. 291 days) than dogs without evidence of mast cell infiltration (P<0.0001). Routine splenic aspiration should be performed regardless of ultrasonographic appearance in dogs with a clinically aggressive mast cell tumor.  相似文献   

THE EFFICIENCY OF AGGREGATION INDICES IN THE COMPARISON OF SOME ENGLISH AND CANADIAN SOILS     

RORKE B. BRYAN 《European Journal of Soil Science》1971,22(2):166-178

The efficiency of indices of aggregation was tested by assessing the accuracy with which they reflected observed differences between selected samples from a variety of Albertan and Derbyshire soils. The most efficient indices were shown to be the percentage-weight of water-stable aggregates > 3 mm, > 2 mm, > 1 mm, > 0.5 mm, the coefficient of aggregation, and the mean-weight diameter. Indices also showed highly significant variations in aggregation between fourteen soil groups, ranging from humus-iron podzol to brown solodized-solonetz. The Derbyshire soils showed significantly higher aggregate stability than those from Alberta. These differences may be the result of variations in clay mineral type, sodium content and climatic factors.  相似文献   

Septic Arthritis of the Distal Interphalangeal Joint in 12 Horses     

CLIFFORD M. HONNAS DVM  Dipiomate ACVS    ROBERT D. WELCH DVM  PhD  Dipiomate ACVS    TROY S. FORD DVM  Dipiomate ACVS    JOHN R. VACEK DVM  JEFFREY P. WATKINS DVM  MS  Dipiomate ACVS 《Veterinary surgery : VS》1992,21(4):261-268

The medical records of 12 horses with septic arthritis of a distal interphalangeal joint were reviewed to determine clinical features and response to treatment. Sepsis was caused by trauma or an injection that resulted in an open or contaminated distal interphalangeal joint. All horses were severely lame. Treatment included broad-spectrum parenterally administered antimicrobial drugs (ten horses), percutaneous through-and-through joint lavage (eight horses), indwelling drains (three horses), immobilization of the limb in a cast (three horses), intraarticular injection of sodium hyaluronate (one horse), intraarticular injection of antimicrobial drugs (five horses), curettage of the distal phalanx (one horse), and cancellous bone grafting to promote fusion (one horse). Five horses were euthanatized. Ankylosis of the affected joint developed in five horses, four of which are pasture sound. Two horses treated medically are sound although one underwent subsequent palmar digital neurectomy for treatment of navicular syndrome.  相似文献   

Effect of Tibial Plateau Leveling Osteotomy on Femorotibial Contact Mechanics and Stifle Kinematics     

STANLEY E. KIM  BVSc    ANTONIO POZZI  DMV  MS  Diplomate ACVS    SCOTT A. BANKS  PhD    BRYAN P. CONRAD  MEng    DANIEL D. LEWIS  DVM  Diplomate ACVS 《Veterinary surgery : VS》2009,38(1):23-32

Objective— To evaluate the effects of tibial plateau leveling osteotomy (TPLO) on femorotibial contact mechanics and 3-dimensional (3D) kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs.
Study Design— In vitro biomechanical study.
Animals— Unpaired pelvic limbs from 8 dogs, weighing 28–35 kg.
Methods— Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135°. Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TPLO-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test ( P <.05) was used for statistical comparison.
Results— Significant disturbances to all measured contact mechanical variables were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and increased internal tibial rotation in the CrCL-deficient stifle. No significant differences in 3D femorotibial alignment were observed between normal and TPLO-treated stifles; however, femorotibial contact area remained significantly smaller and peak contact pressures in both medial and lateral stifle compartments were positioned more caudally on the tibial plateau, when compared with normal.
Conclusion— Whereas TPLO eliminates craniocaudal stifle instability during simulated weight bearing, the procedure fails to concurrently restore femorotibial contact mechanics to normal.
Clinical Relevance— Progression of stifle osteoarthritis in dogs treated with TPLO may be partly the result of abnormal stifle contact mechanics induced by altering the orientation of the proximal tibial articulating surface.  相似文献