Delayed Mortality Rates Research Articles

Patterns, drivers, and implications of postfire delayed tree mortality in temperate conifer forests of the western United States

AbstractConifer forest resilience may be threatened by increasing wildfire activity and compound disturbances in western North America. Fire refugia enhance forest resilience, yet may decline over time due to delayed mortality—a process that remains poorly understood at landscape and regional scales. To address this uncertainty, we used high‐resolution satellite imagery (5‐m pixel) to map and quantify delayed mortality of conifer tree cover between 1 and 5 years postfire, across 30 large wildfires that burned within three montane ecoregions in the western United States. We used statistical models to explore the influence of burn severity, topography, soils, and climate moisture deficit on delayed mortality. We estimate that delayed mortality reduced live conifer tree cover by 5%–25% at the fire perimeter scale and 12%–15% at the ecoregion scale. Remotely sensed burn severity (1‐year postfire) was the strongest predictor of delayed mortality, indicating patch‐level fire effects are a strong proxy for fire injury severity among surviving trees that eventually perish. Delayed mortality rates were further influenced by long‐term average and short‐term postfire climate moisture deficits, illustrating the impact of drought on fire‐injured tree survival. Our work demonstrates that delayed mortality in conifer forests of the western United States can be remotely quantified at a fine grain and landscape scale, is a spatially extensive phenomenon, is driven by fire–climate–environment interactions, and has important ecological implications.

Comparison of in-hospital and long-term mortality and assessment of their predictors in patients with myocardial infarction and unstable angina

Background: The extent of myocardial damage largely determines both in-hospital and long-term mortality in patients with acute coronary syndrome. According to the literature, the in-hospital and long-term mortality rates in patients with unstable angina (UA) are lower than those in the patients with myocardial infarction (MI).
 Aim: To evaluate the in-hospital and long-term mortality rates and their predictors in patients undergoing in-patient treatment for acute coronary syndrome (MI and UA) in the regional cardiovascular center with the service territory of 1 million persons.
 Materials and methods: This retrospective registry study enrolled 1130 patients (715 [63.3%] men, 415 [36.7%] women) who were treated for UA and MI in the regional cardiovascular center in 2019. Based on the discharge diagnosis, the patients were divided into two groups: patients with MI (n = 766) and those with an UA episode (n = 364). The in-hospital and delayed mortality rates, as well as their predictors, were analyzed in both groups. The mean duration of the follow-up was 17.8 3.6 months.
 Results: The in-hospital mortality in patients with confirmed MI was 11.1% (85 patients) versus 0.27% (1 patient) in the UA patients (p 0.001). The independent predictors of in-hospital mortality in MI patients were a decreased left ventricular ejection fraction (LV EF) (odds ratio (OR) 0.9021, 95% confidence interval (CI) 0.82090.9914, p = 0.0324), chronic kidney disease C3a and above (OR 9.3205, 95% CI 2.670632.5283, p = 0.0005), and the extension of coronary involvement at coronary angiography (OR 1.3526, 95% CI 1.06670.0127, p = 0.0127). The long-term mortality in MI patients was 10.4% (72 patients) with no significant difference from that in UA patients (9.9%, 36 patients, p = 0.76). The independent predictors of long-term mortality after MI were older age (OR 1.12, 95% CI 1.011.22, p = 0.0052), chronic kidney disease C3a and above (OR 2.3375, 95% CI 1.13924.7963, p = 0.0206), decreased EF (OR 0.8895, 95% CI 0.730.99, p = 0.0364), atrial fibrillation on admission (OR 3.1462, 95% CI 1.35107.3268, p = 0.0079), and diabetes mellitus (OR 2.3163, 95% CI 1.25524.2744, p = 0.0072). In the UA patients, the predictors of the long-term mortality were a decrease in LV EF (OR 0.9139, 95% CI 0.86830.9619, p = 0.0006) and in blood hemoglobin level (OR 0.9729, 95% CI 0.95440.9917, p = 0.0050).
 Conclusion: The in-hospital mortality in UA patients is lower than that in MI patients, with comparable long-term mortality. This indicates the need of active follow-up of the patients with past UA, irrespective of the endovascular assessment and intervention.

Evaluation of the Efficacy of Fludora® Fusion WP-SB 56.25 (Mixture of Clothianidin and Deltamethrin) against Anopheles coluzzii Laboratory and An. arabiensis Wild Colonies.

For malaria control, the application of long-lasting insecticidal nets and indoor residual spraying has led to a significant reduction in morbidity and mortality. However, the sustainability of these gains is hampered by the increase in insecticide resistance. It is therefore judicious to evaluate new insecticide formulations. In comparison to clothianidin and deltamethrin, the efficacy and residual effect of Fludora® Fusion was evaluated using an Anopheles coluzzii laboratory and An. arabiensis wild colonies in huts from August 2016 to June 2017 on cement and mud walls. Mortality was recorded at 24, 48, 72, and 96 h post exposure. Like deltamethrin and clothianidin, Fludora® Fusion showed delayed mortality rates above the WHO’s 80% threshold over a period of 11 months with the laboratory strain. With the wild strain, while residual efficacy was observed at 2 months for the three insecticides, no residual efficacy was observed at 8 months at 24 h in both substrates. However, the increased efficacy was observed with increased holding periods (72 h and 96 h). These findings suggest that Fludora® Fusion could be an alternative candidate since this duration covers the transmission period in most areas in Senegal.

Immediate and Delayed Mortality of Four Stored-Product Pests on Concrete Surfaces Treated with Chlorantraniliprole.

Simple SummaryWe examined the mortality caused by the anthranilic diamide, chlorantraniliprole, at four different doses applied on concrete (0.01, 0.05, 0.1, and 0.5 mg a.i./cm2) in Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) adults and larvae, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) adults, and Acarus siro L. (Sarcoptiformes: Acaridae) adults and nymphs. Mortality data were recorded after 1, 2, 3, 4, and 5 days to determine the immediate mortality. Furthermore, after the 5-day mortality counts, still living individuals were conveyed for 7 days to untreated concrete surfaces to estimate the delayed mortality. The highest immediate mortality was recorded for the larvae of T. castaneum, reaching 96.7%, followed by the adults of A. siro (92.2%) after 5 days of exposure to 0.5 mg a.i./cm2. Complete (100.0%) delayed mortality was noticed for T. castaneum (adults and larvae), S. oryzae, and A. siro (both as adults) at 0.5 mg a.i./cm2. Rhyzopertha dominica adults and A. siro nymphs exhibited 98.6% and 96.3% delayed mortality at the same dose, respectively. Overall, our results demonstrate that chlorantraniliprole is effective against all the species tested, causing varying immediate and delayed mortality rates at the developmental stages tested.Chlorantraniliprole is an effective pesticide against a plethora of pests, but its efficacy against stored-product pests is very poorly explored. In this study we treated concrete surfaces with four different doses of chlorantraniliprole (0.01, 0.05, 0.1, and 0.5 mg a.i./cm2) against the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) adults and larvae, the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) adults, and the flour mite, Acarus siro L. (Sarcoptiformes: Acaridae) adults and nymphs, to examine the immediate mortalities after 1, 2, 3, 4, and 5 days of exposure. Additionally, the delayed mortality of the individuals that survived the 5-day exposure was also evaluated after a further 7 days on untreated concrete surfaces. We documented high mortality rates for all tested species and their developmental stages. After 5 days of exposure to 0.5 mg a.i./cm2, T. castaneum larvae and A. siro adults exhibited the highest immediate mortality levels, reaching 96.7% and 92.2%, respectively. Delayed mortality was also very high for all tested species and their developmental stages. Nymphs of A. siro displayed a 96.3% delayed mortality followed by the adults of R. dominica (98.6%) after exposure to 0.5 mg a.i./cm2. All other tested species and their developmental stages reached complete (100.0%) delayed mortality, where even 0.01 mg a.i./cm2 caused ≥86.6% delayed mortality in all species and their developmental stages. Taking into consideration the effectiveness of chlorantraniliprole on this wide range of noxious arthropods, coupled with its low toxicity towards beneficial arthropods and mammals, this pesticide could provide an effective management tool for stored-product pests in storage facilities.

The effect of gillnet capture on the metabolic rate of two shark species with contrasting lifestyles

In this study we investigated the metabolic consequences of simulated gillnet capture in species with contrasting life-history characteristics, the gummy shark, Mustelus antarcticus and the Port Jackson shark, Heterdontus portusjacksoni. Pre-stress standard and routine metabolic rates (MR) of individuals of these species were measured and compared to the MR obtained after simulated gillnet capture. Standard MRs of M. antarcticus and H. portusjacksoni were 168.5 ± 61.9 mgO2 kg-0.67 h−1 and 144.1 ± 20.4 mgO2 kg-0.67 h−1, respectively. Routine MRs of M. antarcticus and H. portusjacksoni were 202.6 ± 63.5 mgO2 kg-0.67 h−1 and 166.4 ± 11.2 mgO2 kg-0.67 h−1, respectively. The simulated gillnet-capture treatment decreased the MR of M. antarcticus by 59.3% and increased that of H. portusjacksoni by 21.6%. Our results confirm that M. antarcticus is highly sensitive to gillnet capture, exhibiting significant variability in MR among individuals and also a high delayed mortality rate. We interpret the decrease in MR as a compensatory mechanism for reducing oxygen consumption to cope with the stress imposed by capture. Mortality in this species was associated with higher pre-stress MR, and lower post-stress MR. In contrast, H. portusjacksoni showed mild increases in MR. Their resilience to capture stress most likely relies on effective buccal pumping and lower basal MR. A mixed-effects model approach permitted us to identify the main sources of variation in the MR measured, which were the individual differences, treatment effects, species variations and delayed mortality. The comparative approach employed in this work allowed us to understand and provide reliable estimates of the effects of fishing on the MRs of these two species.

High level of methylmercury exposure causes persisted toxicity in Nauphoeta cinerea.

Methylmercury (MeHg+) is a neurotoxicant abundantly present in the environment. The long-term effects of MeHg+ have been investigated in rodents, yet data on the long-term or persisted toxicity of MeHg+ in invertebrates is scanty. Here, we examined the acute, intermediate, and chronic effects upon dietary administration of MeHg+ in nymphs of Nauphoeta cinerea. Besides, the potential reversibility of the toxic effects of MeHg+ after a detoxification period was evaluated. Nymphs were exposed to diets containing 0 (control), 2.5, 25, and 100μg MeHg+/g of diet for 10, 30, and 90days. Additional groups of nymphs were fed with the same dose of MeHg+ for 30days and then were subjected to a detoxification period for 60days. The nymphs exposed to 100μg MeHg+/g succumbed to a high mortality rate, along with multiple biochemical (increase of reactive oxygen species production and glutathione S-transferase activity, as well as decrease in the acetylcholinesterase activity) and behavioral alterations. We observed delayed mortality rate and behavioral alterations in nymphs exposed to 100μg MeHg+/g for 30days and subsequently subjected to 60days of detoxification. However, the biochemical alterations did not persist throughout the detoxification period. In conclusion, our results established the persistent toxic effect of MeHg+ even after a prolonged detoxification period and evidenced the use of N. cinerea as an alternative model to study the toxicity of MeHg+.

Legacy habitat contamination as a limiting factor for Chinook salmon recovery in the Willamette Basin, Oregon, USA.

In the western United States, the long-term recovery of many Pacific salmon populations is inextricably linked to freshwater habitat quality. Industrial activities from the past century have left a legacy of pollutants that persist, particularly near working waterfronts. The adverse impacts of these contaminants on salmon health have been studied for decades, but the population-scale consequences of chemical exposure for salmonids are still poorly understood. We estimated acute and delayed mortality rates for seaward migrating juvenile Chinook salmon that feed and grow in a Superfund-designated area in the Lower Willamette River in Portland, Oregon. We combined previous, field-collected exposure data for juvenile Chinook salmon together with reduced growth and disease resistance data from earlier field and laboratory studies. Estimates of mortality were then incorporated into a life cycle model to explore chemical habitat-related fish loss. We found that 54% improved juvenile survival—potentially as a result of future remediation activities—could increase adult Chinook salmon population abundance by more than 20%. This study provides a framework for evaluating pollution remediation as a positive driver for species recovery.

Suppression of argonautes compromises viral infection in Penaeus monodon

Argonaute (Ago) proteins, the catalytic component of an RNA-induced silencing complex (RISC) in RNA interference pathway, function in diverse processes, especially in antiviral defense and transposon regulation. So far, cDNAs encoding four members of Argonaute were found in Penaeus monodon (PmAgo1-4). Two PmAgo proteins, PmAgo1 and PmAgo3 shared high percentage of amino acid identity to Ago1 and Ago2, respectively in other Penaeid shrimps. Therefore, the possible roles of PmAgo1 and PmAgo3 upon viral infection in shrimp were characterized in this study. The level of PmAgo1 mRNA expression in shrimp hemolymph was stimulated upon YHV challenge, but not with dsRNA administration. Interestingly, silencing of either PmAgo1 or PmAgo3 using sequence-specific dsRNAs impaired the efficiency of PmRab7-dsRNA to knockdown shrimp endogenous PmRab7 expression. Inhibition of yellow head virus (YHV) replication and delayed mortality rate were also observed in both PmAgo1-and PmAgo3-knockdown shrimp. In addition, silencing of PmAgo3 transcript, but not PmAgo1, revealed partial inhibition of white spot syndrome virus (WSSV) infection and delayed mortality rate. Therefore, our study provides insights into PmAgo1and PmAgo3 functions that are involved in a dsRNA-mediated gene silencing pathway and play roles in YHV and WSSV replication in the shrimp.

Condition and mortality of western painted turtle collected as bycatch in modified fyke nets during fish population assessments

ABSTRACTInformation concerning turtle bycatch and its possible ramifications during biological sampling in freshwater systems is limited. Having such information will enable fisheries researchers and managers to modify fish sampling procedures to potentially minimize any impacts on turtle populations. Therefore, our objective was to utilize reflex response to characterize stress and mortality of western painted turtles (Chrysemys picta bellii) captured as bycatch in modified fyke nets during fish population assessments. Reflex-response-based condition classification (i.e. good, poor, unresponsive) data were collected from May to September during fish population assessments in 38 lakes and seven impoundments in northeast South Dakota from 2012 to 2014. We evaluated the relationship between observed condition and water temperature during two time periods, by turtle gender and size. Turtle bycatch mortality was assessed from June to September during fish population assessments in 14 lakes and three impoundments during 2013 and 2014. Delayed (i.e. overnight) mortality was determined for poor and unresponsive condition classifications and the relationship between observed mortality and water temperature for two time periods, by turtle gender and size was evaluated. Turtle condition decreased as water temperature increased. Condition was poorer during the May and June time period than August and September. Female turtles were in significantly worse condition than males. Condition was not related to turtle size. We observed varying mortality rates across condition classifications and the total estimated delayed mortality rate of known sex turtles was 36.4%. Mortality increased as temperature increased. Delayed mortality rates varied between the two sampling periods with higher mortality rates during the May and June time period. Female turtles had higher mortality rates than males. Delayed mortality did not vary by turtle size. Understanding the negative effects on bycatch during biological sampling is important to provide justification for the development and implementation of measures to protect non-target species.

Post-Capture Survival and Implications for By-Catch in a Multi-Species Coastal Gillnet Fishery.

As fisheries shift towards ecosystem-based management, the need to reduce impacts on by-catch has been increasingly recognised. In this study the catch composition, discard rate, and post-capture survival of species caught by gillnets in Tasmania, Australia, was investigated. Over half the commercial gillnet catch was discarded, with discard rates of ~20% for target and >80% for non-target species. Capture condition, including initial mortality, was assessed using simple criteria for a range of species and related to soak duration. Delayed mortality was also assessed using tank trials and related to capture condition. By combining initial and delayed mortality rates post-capture survival was estimated. Longer soak durations generally resulted in slight, but significant, declines in capture condition and lower initial survival. Nonetheless, when combined with delayed survival, four of the five most commonly caught species (Cheilodactylus spectabilis, Latridopsis forsteri, Aplodactylus arctidens, Cephaloscyllium laticeps) exhibited high post-capture survival (83–100%) for soak durations within the maximum regulated range. Post-capture survival of the one remaining commonly caught species, Notolabrus tetricus, (typically discarded) declined with increased soak duration from 84% to 62%, suggesting that this species would benefit from a further reduction in maximum soak duration. Initial and delayed survival rates for the species retained for tank trials exhibited a significant linear relationship, which was used to estimate delayed survival rates for the rarer species. This method enabled the estimation of potential post-capture survival rates for a diverse range of species and may have application in other data-limited situations where the relationships between fishing practices and by-catch survival are uncertain. Overall, our results suggest that soak duration regulation has been effective in reducing by-catch mortality for many species, noting that some species have low survival rates regardless of soak duration.

Fournier’s Gangrene

Fournier's gangrene is a usually polymicrobial, necrotizing, life-threatening fasciitis of the perineal, genital and perianal region. It is a fulminant disease which can rapidly spread to the abdominal wall and cause a high mortality. It is important to diagnose the disease process as early as possible as when the tyreatment is delayed mortality rate is directly increased.

Linking “Sink or Swim” Indicators to Delayed Mortality in Red Snapper by Using a Condition Index

Abstract The ability of fish to submerge after discarding is often used as a proxy for survival, but this practice underestimates total discard mortality because delayed mortality is overlooked. Fishery managers need a way to link “sink or swim” indicators, or variables observed during capture and release, with delayed mortality rates. We conducted a cage study of red snapper Lutjanus campechanus off the coast of Texas to estimate delayed mortality rates and to find factors that could link immediate and delayed mortality. Immediate mortality (17%) was predicted by the interaction of depth and the difference in temperature between surface and bottom waters. Lactate levels were also significant predictors of immediate mortality in fish whose blood was tested. Delayed mortality (64%) was predicted primarily by a condition index consisting of the presence or absence of injuries, symptoms of barotrauma, and fish behaviors immediately after capture. Specific categories included bleeding, protruding intestines, everted stomach, exopthalmia, the presence or absence of flapping and gilling behaviors, and problems with cage submergence. The majority of fatalities occurred within 24 h after fish were placed in the cages. Our mortality estimates indicate that red snapper discard mortality was significantly underestimated in the 2005 stock assessment for red snapper. The use of indices that relate the condition of an individual fish at capture to its probability of delayed mortality is an excellent method for linking immediate and delayed mortality and will likely be applicable to many species that are subject to catch-and-release fishing.

Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish

Abstract Davis, M. W. 2007. Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish. – ICES Journal of Marine Science, 64: 1535–1542. Development of efficient methods to predict discard and escapee mortality in fishing operations is essential to the conservation of sensitive fish stocks. For a few fisheries, mortality data are available from fishing experiments in the field; these require long-term holding or monitoring of fish in tanks, cages, or tag and recapture experiments to detect delayed mortality. A different approach to predicting discard and escapee mortality is to use reflex action mortality predictors (RAMP) consisting of relationships between mortality and reflex impairment for species of interest. Fish were towed in a net in the laboratory and then either restrained in foam-lined holders and rapidly tested for reflex impairment five minutes after towing, or held for up to 60 days to determine delayed mortality. Delayed mortality occurred up to 20 days after towing. RAMP was related to mortality with biphasic sigmoid functions. As fishing stressors increased in intensity, the first phase showed an increase in RAMP with no concomitant mortality. In the second phase, RAMP continued to increase, while mortality became apparent and increased. The measurement of RAMP in restrained fish on board fishing vessels during experiments to predict discard mortality and in caged free swimming fish to predict escapee mortality is feasible and advisable.

Effects of different Beauveria bassiana isolates on field populations of Lygus lineolaris in pigweed (Amaranthus spp.)

Abstract The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is a pest of various fruit, vegetable, fiber, and seed crops; including cotton. Lygus spp. populations often build on alternate host plants before moving to cotton, and in the midsouthern U.S. wild host plants, such as pigweed (Amaranthus spp.), play a major role in L. lineolaris population development. Three isolates of the entomopathogenic fungus Beauveria bassiana (Balsamo) were evaluated for L. lineolaris control in redroot pigweed (Amaranthus retroflexus L.): one from L. lineolaris in Mississippi (TPB3); one from Lygus hesperus (Knight) in California (WTPB2); and one commercial isolate from Mycotrol® (GHA). Fungal applications resulted in moderate to high mycosis in adults (33 to 80%) and moderate mycosis in nymphs (36 to 53%) that were collected from field plots at 2 days post-treatment and incubated under laboratory conditions. Although TPB3 was previously found to be more pathogenic in laboratory bioassays, there was not a consistent separation of this isolate from the other two isolates in field trials. Where differences in adult mycosis or mortality were observed, TPB3 was the most pathogenic. However, in one field trial 7 day mortality for nymphs treated with GHA was higher than those treated with TPB3 or WTPB2. Infection rates at 2, 7, and 14 days post-treatment from caged and non-caged adults suggested that movement of adults among plots occurred, which could have masked some treatment effects. Fungal treatments did not significantly reduce populations relative to controls. This may have been caused by delayed mortality rates under field conditions and/or difficulties with estimating population change under field conditions characteristic of wild host plant populations (e.g., heterogeneous populations, adult movement, and small plot size). Further work evaluating time–dose–mortality over dynamic temperatures, spring and fall field trials on this and other wild hosts, and improved methods for estimating populations on wild hosts are needed.

Factors Related to Mortality of Black Bass Caught during Small Club Tournaments in Connecticut

Abstract Factors related to the initial and delayed mortality of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu were determined at small club tournaments held at two Connecticut lakes during April–October of 2001–2002. Organizational characteristics of tournaments, environmental conditions, and initial mortality data were collected from 58 tournaments at Mansfield Hollow Reservoir and 41 tournaments at Gardner Lake. Delayed mortality at 72 h was also determined for 29 tournaments at Mansfield Hollow Reservoir and 25 tournaments at Gardner Lake. In total, 3,290 largemouth bass and 1,035 smallmouth bass were observed for initial mortality; 1,784 largemouth bass and 647 smallmouth bass were observed for 72-h delayed mortality. Initial and delayed mortality rates were 2.2% and 1.0% for largemouth bass and 4.8% and 2.8% for smallmouth bass. Logistic regression indicated that initial mortality was significantly greater (P < 0.0001) for smallmouth bass than for largemouth bass, and that initial mortality was positively related to water temperature (P < 0.0001), total handling time (P < 0.0001), and fishing-day length (P = 0.0357). Delayed mortality was positively related to water temperature (P < 0.0001), and there was a significant species × lake interaction (P = 0.0152). Initial mortality began to increase sharply at water temperatures greater than 25°C. Delayed mortality showed differential responses to water temperature depending on the species and lake. Our results suggest that tournament-associated mortality may be reduced by limiting tournament activity during the hottest months and by increasing the efficiency of weigh-in procedures at small club tournaments.

Influence of prestroke dementia on early and delayed mortality in stroke patients.

Causes of early and delayed death after stroke differ. It has been suggested that delayed mortality rate was increased in patients with post-stroke dementia. Prestroke dementia is frequent: its influence on survival in stroke patients has never been evaluated. The aim of this study was to evaluate the influence of prestroke dementia on early and delayed mortality rate after stroke. In a cohort of 202 consecutive stroke patients aged >or= 40 years admitted between November 1995 and May 1996 in a primary care center, the prevalence of prestroke dementia was determined using the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) with a cut-off of 104. Patients were followed-up for 3 years. Statistics were performed using life-table methods. Of 202 patients, 33 had prestroke dementia. Of 142 survivors at month-6, 44 were demented, of them 15 having prestroke and 29 new-onset post-stroke dementia. No patient was lost to follow-up. The risk of death at month-6 was higher in patients with prestroke dementia (RR 2.7; 95 % CI: 1.6-4.8). However, independent predictors of early death were age, severity of the deficit at admission, type and etiology of stroke. The risk of delayed death was higher in patients with prestroke dementia (RR 4.97; 95 % CI: 1.76-13.98) as in patients with new-onset post-stroke dementia (RR 6.24; 95 % CI: 2.67-14.57), compared with non-demented patients. The mortality rate did not differ between patients with prestroke and new-onset post-stroke dementia. Dementia at month-6 was an independent predictor of delayed death (RR 5.7; 95 % CI: 2.4-13.4), with age and stroke recurrence. Causes of death did not differ between demented and non-demented patients. Dementia adversely influences vital outcome in stroke patients, perhaps partly because the therapeutic approach differs between demented and non-demented patients.

Mortality of Largemouth Bass during Catch-and-Release Tournaments in a Puerto Rico Reservoir

In Puerto Rico, unique protocols are used during fishing tournaments for largemouth bass Micropterus salmoides. Live wells are not required, and many anglers retain their catch on metal stringers. During day tournaments, fish are collected and weighed by a roving weigh-in boat; night tournaments use a central weigh-in station. We monitored 15 fishing tournaments over 1 year in Lucchetti Reservoir, Puerto Rico, to quantify mortality rates and to evaluate the impact of tournaments on the adult fish population. Initial mortality was documented at weigh-in, and delayed mortality was determined by holding largemouth bass for 4 d in floating mesh pens with control (electrofished) largemouth bass. Initial and delayed mortality averaged 8% (range, 0–38%) and 43% (10–98%), respectively. The delayed mortality rate was adjusted by the control mortality rate (mean, 7%; range, 0–50%) for each tournament to yield adjusted delayed mortality rate (mean, 36%; range, 10–68%), which we used to calculate total mortality rate (mean, 42%; range, 13–68%). Although surface water temperature ranged only between 23°C and 28°C, total mortality was significantly lower (P ≤ 0.05) during January–February, being positively correlated with temperature. Night tournaments experienced significantly greater total mortality rates than day tournaments, most likely because of the eightfold longer retention of bass before weigh-in during night tournaments. Retention time was positively correlated with initial mortality rates. We estimated that tournament mortality removed 6% of the adult largemouth bass population and accounted for 23% of all fishing mortality. We recommended reducing tournament fishing during hotter, high-mortality periods; modification of night tournaments; and use of well-maintained live wells. Combined with angler education, such modifications of tournament procedures can reduce the impact of tournaments in tropical reservoirs.

Differences in Mortality between Largemouth and Smallmouth Bass Caught in Tournaments

Abstract We monitored nine tournaments on three lakes in Maine between June and October 1989 to determine initial and delayed mortality rates of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu. Initial mortalities were defined as fishes that were dead at the weigh-in, whereas delayed mortalities were fishes that died during a 48-h holding period after the tournament. Total mortalities (initial and delayed) for both species ranged from 0 to 19.5%. Mortalities were lowest in tournaments that minimized both the number of steps and the time elapsed between the removal of a fish from a live well and the subsequent release of the fish into the lake, We estimated that 8.9% of smallmouth bass and 3.2% of largemouth bass died during tournaments; the probability of either species dying in a large tournament was significantly higher than in a small tournament.

Hooking Mortality of Chinook Salmon Released by Commercial Trollers

Immediate and short-term (1–5-d) hooking mortality associated with the incidental catch of chinook salmon Oncorhynchus tshawytscha was assessed during periods when troll fishing for that species (only) was prohibited. Two chartered power trollers fished their normal complements of gear directed at coho salmon O. kisutch in Hawk Inlet, southeastern Alaska. Wound location, fork length, and lure type were the factors principally associated with mortality of incidentally caught chinook salmon. Severity of the hooking wound was also related to mortality. Maximum-likelihood estimates (with 95% confidence intervals in parentheses) of total mortality were 24.5% (20.1–29.0%) for sublegal-sized (<66 cm fork length) chinook salmon and 20.5% (9.0–31.9%) for legal-sized chinook salmon. The delayed-mortality rates were used to recalculate hooking mortality estimates from previous tagging experiments in which it was assumed that no delayed mortality occurred for certain locations and severities of wounds. The recalculated estimate of total hooking mortality for sublegal fish, based on wound location, was 25.7%. The recalculated estimate of total hooking mortality for legal and sublegal fish, based on wound severity, was 23.5%.

Essais de prevention et traitement du mal des rayons chez le poussin

Des poussins de race Rhode Island, âgés de 19 à 21 jours, sont exposés aux rayons-X. S'ils reçoivent une dose totale de 2000 r (débit: 100 r/min), la majorité de décès survient au course des48 premières heures. Il existe deux phases de létalité, l'une précoce, l'autre tardive. Parmi des radioprotecteurs très efficaces chez la souris et le rat (cystéamine, cystamine, cystéine, tryptamine, diéthyldithiocarbamate de sodium, acide éthylènediaminotétraacétique, cyanure de sodium), seuls, le diéthyldithiocarbamate de sodium et la tryptamine sont faiblement actifs chez le poussin; le premier agit sur les deux phases de létalité, le second ne réduit que la mortalité tardivé. Il est peu probable qu'ils agissent par anoxie. Les troubles fonctionnels et métaboliques qui suivent l'irradiation sont graves et précoces chez le gallinacé (collapsus circulatoire, libération d'histamine, hyperkaliémie). La déplétion préalable des stocks d'histamine tissulaire par la peptone et le 48/80 réduit le nombre de décès précoces sans modifier la mortalité tardive. Le Néoantergan est le seul parmi les antihistaminiques étudiés qui ait une action radioprotectrice. Celle-ci est appréciable au cours des deux phases de létalité. Injecté à titre curatif, il devient inefficace. Les traitements visant respectivement à corriger l'hyperkaliémie, à pallier un éventuel déficit cortico-surrénalien ou à lutter contre l'infection, sont restés sans résultats. Rhode Island chicks aged 19 to 21 days are exposed to X-rays. If they receive a total dose of 2000 r (at a rate of 100 r/min), most of the deaths occur within the first 48 hours. There are two phases of lethality, one rapid and the other delayed. Among radio-protective substances which are very effective in the mouse and rat (cysteamine, cystamine, cysteine, tryptamine, sodium diethyldithiocarbamate, ethylenediaminotetracetic acid, sodium cyanide) only sodium diethyldithiocarbamate and tryptamine are feebly active in the chick; the former affects both lethality phases, the latter reduces only the delayed mortality. It is unlikely that they act by anoxia. The functional and metabolic disturbances resulting from irradiation are serious and appear promptly in fowls (circulatory breakdown, liberation of histamine, hyperkaliemia). Preliminary depletion of histamine reserves in the tissues by means of peptone and 48/80 reduces the number of early deaths without altering the delayed mortality rate. Of the anti-histamines studied, Neoantergan alone has a radioprotective action. This is appreciable in both lethality phases. When administered with curative intent, it becomes ineffective. Treatments aiming at correcting hyperkaliemia, palliating a subsequent cortico-surrenal deficiency or fighting infection have been without result. Цыплятa пopoды Poд Aйлeнд в бoзpacтe oт 19 дo 21 дня пoдвepгaлиь дeйcтвию peнтгeнoвcкич лyчeй. Д oзa тoтaлвнoгo oвлyчeнияcocтaвлялa 2000 p пpи мoщнocти дoэы 100/p мин. Cмepть нacтyпaлa чaщe вceгo в тeчeниe пepвыч 48 чacoв. Haблюдaлиcь двa пикa cмepтнocти—oдин paнний, дpyгoй пoэдний. иэ чиcлa вeщecтв, oблaдaющич выpaжeнным эaщитным дeйcтвиeм для мышeй и кpыc (циcтeaмин, циcтaмин, циcтeин, тpиптaмин, диэтилдитиoкapбaмaт нaтpия, этилeндиa- минтeтpayкcycнaя киcлoтa, циaниcтый), тoлькo диэтилдитиoкapбaмaт нaтpия и тpиптaмин нмeют cлaбo выpaжeннoe зaщитнoe дeйcттвиe пo oтмoшeнию к цышлятaм; пepвый влияeт нa pбa пикa cмepтнocти, втopoй нe cнижaeт пикa. Maлo вepoятнo, чтo эффeктивнocть этич вeщecтв oбycлoвлeнa aн oкcиeй. Фyнкциoнaльныe и oбмeнныe нapyшeния, вызвaнныe oблyчeниeм, cильнo выpaжeны и paнo пpoявляютcя y кyp (циpкyлятopныe кoллaпcы, выcвoбoждeниe гиcтaминa, гипepкaлиeмия). П peдвapитeльнoe иcтoщeниe зaпacoв ткaнeвoгo гиcтaминa c пoмoцью пeптoнa и 48/80 cнижaeт кoличecтвo paннич cмepтeй, нe oкaзывaя вoздeйcтвия нa пoздний пик cмepтнocти. Heoaнтepгaн являeтcя eдиcтвeнным иэ иccлeдoвaнныч aнтигиcтaминныч вeщecтв, кoтopoe oкaэывaeт эaщитнoe дeйcтвиe. Oнo пpoявляeтcя в oтнoшeнии oбoич пикoв. Пpи ввeднии пocлe oблyчeния нeoaнтepгaн oк laэывaeтcя нeэффeктивым. Tepaпeвтичecкиe мepы, пpeдпинятыe для cнижeния гипepкaлиeмии, для выpaвнивaния пpeдпoлaгaeмoй к lopтикo-нaдпoчeчникoвoй нeдocтaтoчнocти или для бopьбы c инфeкциeй ocтaютcя бeзpeзyльтaтными. 19 bis 21 Tage alte Rhode Island-Kücken werden röntgenbestrahlt. Bei 2000 r Gesamtdosis (Dosisrate: 100 r/min) tritt der Tod in der Mehrzahl der Fälle bereits innerhalb der ersten 48 Stunden ein. Es treten 2 Lethalitäsphasen auf, eine vorzeitige und eine verzögerte. Von den bei Maus und Ratte äusserst wirksamen Radioschutzmitteln (Cysteamin, Ciystamin, Cstein, Tryptamin, Natrium-Diäthyldithiocarbonat, Äthylendiamin-Tetraessigsäure, Natrium-Cyanid) sind vor allem Natrium-Diäthyldithiocarbaminat und Tryptamin bei jungen Hühnern von einer gewissen schwachen Wirksamkeit. Das erstgenannte wirkt sich auf beide Lethalitäsphasen aus, während das letztere nur die Zhal der verzögert lethalen Fälle herabsetzt. Dass es sich dabei um Anoxie handelt, ist wenig wahrscheinlich. Funktions- und Stoffwechselstörungen (Kollaps, Histaminausschwemmung, Hyperkaliämie) als Folge von Bestrahlung sind bei Hühnern schwerwiegend und treten frühzeitig auf. Eine vorhergehende Entleerung der Vorräte an Gewebshistaminen durch Pepton und “48/80” verringert die Zahl der frühzeitigen Todesfälle, ohne jedoch die verzögerte Mortalität zu beeinflussen. Von den untersuchten Antihistaminen ist Neoantergan das einzige, dem eine Wirkung als Radioschutzmittel zukommt. Siemacht sich während beider Lethalphasen bemerkbar. Diese Wirksamkeit verschwindet jedoch, wenn Neontergan zu Heilzwecken injiziert wird. Behandlungsversuche in der Richtung Korrektion der Hyperkaliämie, der Kompensation einer eventuellen Störung der Nebenniere, oder einer Bekämpfung bleiben ohne Resultat.