The Killer Download
Gaia Shaw
\"This is a killer who is preying on the unhoused,\" Bass said. \"We are calling Angelinos to come together. The city and the region is mobilizing to find this individual. ... We will find you, we will catch you and you will be held accountable.\"
We monitor the Plan's progress and ensure it meets the MMPA goal of reducing mortality and serious injury of false killer whales incidental to the fisheries addressed by the Plan. If mortality and serious injury is not reduced to appropriate levels, we will reconvene the Team to develop additional measures.
When trained chefs George & Katie Brown set out to spice up a plain bag of Texas pecans, a killer snack was born. Sweet and spicy with a bold kick, Killer Pecans combines the crunch of fresh Mammoth pecans with chef-crafted flavor for a Texas-sized taste that is truly chef's kiss.
Why females of some species cease ovulation prior to the end of their natural lifespan is a long-standing evolutionary puzzle [1-4]. The fitness benefits of post-reproductive helping could in principle select for menopause [1, 2, 5], but the magnitude of these benefits appears insufficient to explain the timing of menopause [6-8]. Recent theory suggests that the cost of inter-generational reproductive conflict between younger and older females of the same social unit is a critical missing term in classical inclusive fitness calculations (the "reproductive conflict hypothesis" [6, 9]). Using a unique long-term dataset on wild resident killer whales, where females can live decades after their final parturition, we provide the first test of this hypothesis in a non-human animal. First, we confirm previous theoretical predictions that local relatedness increases with female age up to the end of reproduction. Second, we construct a new evolutionary model and show that given these kinship dynamics, selection will favor younger females that invest more in competition, and thus have greater reproductive success, than older females (their mothers) when breeding at the same time. Third, we test this prediction using 43 years of individual-based demographic data in resident killer whales and show that when mothers and daughters co-breed, the mortality hazard of calves from older-generation females is 1.7 times that of calves from younger-generation females. Intergenerational conflict combined with the known benefits conveyed to kin by post-reproductive females can explain why killer whales have evolved the longest post-reproductive lifespan of all non-human animals.
This paper argues incumbent firms may acquire innovative targets solely to discontinue the target's innovation projects and preempt future competition. We call such acquisitions "killer acquisitions." We develop a model illustrating this phenomenon. Using pharmaceutical industry data, we show that acquired drug projects are less likely to be developed when they overlap with the acquirer's existing product portfolio, especially when the acquirer's market power is large due to weak competition or distant patent expiration. Conservative estimates indicate 5.3 percent to 7.4 percent of acquisitions in our sample are killer acquisitions. These acquisitions disproportionately occur just below thresholds for antitrust scrutiny.
Killer whales occupy pelagic and coastal (including inland marine) waters. Southern Resident and transient killer whales spend more time in coastal areas, where their preferred prey is typically found. The Southern Resident population feeds primarily on Chinook salmon, chum salmon to a lesser extent, and occasionally other fish. Transient animals feed on seals and other marine mammals. Offshore animals primarily feed on sharks and other fish.
Offshore killer whales are much less studied, but also form one population extending from southeastern Alaska to California. These whales usually occur more than nine miles off the outer coast. Offshore killer whales are estimated at 300 individuals and have a stable population trend.
Climate change will likely impact all three ecotypes of killer whales (Southern Residents, transients, offshores) in Washington. This will occur mainly through alterations in prey abundance (i.e., availability of Chinook salmon, marine mammals, sharks, and other prey) resulting from (1) changes in marine food webs, (2) alterations in freshwater habitats occupied by salmon (for Southern Residents), and (3) rising sea level, which may submerge or render unsuitable some traditional pinniped rookeries and haulouts (for transients), and some nearshore habitats required by salmon (for Southern Residents). These impacts will likely result from increases in marine and freshwater temperature, increases in ocean acidification, and altered levels of terrestrial precipitation and runoff. Southern Resident whales are specialists on Chinook salmon, which are themselves quite vulnerable to climate change.
All three populations of killer whale occurring in Washington carry heavy loads of environmental contaminants, face a continuing risk of major oil spills in their ranges, are susceptible to a disease outbreak, and will likely experience the impacts of climate change in the future.
Analysing population genomic data from killer whale ecotypes, which we estimate have globally radiated within less than 250,000 years, we show that genetic structuring including the segregation of potentially functional alleles is associated with socially inherited ecological niche. Reconstruction of ancestral demographic history revealed bottlenecks during founder events, likely promoting ecological divergence and genetic drift resulting in a wide range of genome-wide differentiation between pairs of allopatric and sympatric ecotypes. Functional enrichment analyses provided evidence for regional genomic divergence associated with habitat, dietary preferences and post-zygotic reproductive isolation. Our findings are consistent with expansion of small founder groups into novel niches by an initial plastic behavioural response, perpetuated by social learning imposing an altered natural selection regime. The study constitutes an important step towards an understanding of the complex interaction between demographic history, culture, ecological adaptation and evolution at the genomic level.
To better understand and visualize the complexity of the ancestry of killer whale ecotypes, we reconstructed the genetic relationships among ecotypes in the form of a maximum likelihood graph (Fig. 2a), representing the degree of genetic drift and modelling both population splits and gene flow using the unified statistical framework implemented in TreeMix (ref. 24). The inferred migration edges were supported by the three-population (f3) and D-statistic (ABBA-BABA)25 tests, which can provide clear evidence of admixture, even if the gene flow events occurred hundreds of generations ago26. These population genomic methods test for asymmetry in the covariance of allele frequencies that indicate that the relationships among populations are not fully described by a simple bifurcating tree model.
(a) PSMC estimates of changes in effective population size (Ne) over time inferred from the autosomes of a North Atlantic killer whale (red) and from the autosomes of a North Pacific resident killer whale (brown). Thick lines represent the median and thin light lines of the same colour correspond to 100 rounds of bootstrapping. (b) PSMC estimates of changes in Ne over time inferred from the autosomes (NeA, red) and the X-chromosome (NeX, grey) of the high-coverage genome sequence of a North Atlantic female killer whale. Thick lines represent the median and thin light lines of the same colour correspond to 100 rounds of bootstrapping. The dashed black line indicates the ratio of NeX/NeA. (c) Changes in effective population size (Ne) over time in the transients (blue), residents (brown) and type C (orange) inferred using the SFS of each ecotype. Thick lines represent the median and thin light lines the 2.5 and 97.5 percentiles of the SFS analysis.
Overall, the population genetic analyses of the whole-genome sequences above shed light on the ancestry of killer whale ecotypes in unprecedented detail, highlighting a complex tapestry of periods of isolation interspersed with episodic admixture events and strong demographic bottlenecks associated with the founder events that gave rise to the resident, transient and ancestral Antarctic ecotypes.
Demographic bottlenecks during population splits and founding events, followed by subsequent demographic and geographic expansion, can produce rapid shifts in allele frequencies between populations34. The high levels of genome-wide differentiation (FST) between killer whale ecotypes across all genomic regions (Fig. 4a,b) are consistent with strong genetic drift following demographic expansion from small founding groups. Considering the low efficiency of selection in populations as small as the estimates presented here35, in which founder populations have an estimated Ne ranging from a few tens to hundreds, a genome-wide contribution of ecologically mediated divergent selection is neither necessary nor particularly likely to explain the observed shifts in allele frequencies in such a large number of loci. Consistent with this prediction, we find that differentiation is highest along the branches inferred by TreeMix to have experienced the most substantial genetic drift (Fig. 2a), that is, the branch to the ancestor of the Antarctic types and the branch to the resident ecotype (Supplementary Fig. 13). We therefore expect that only those beneficial alleles that have a strong favourable effect (that is, strength of selection (s)>1/2Ne) would have an increased fixation probability because of selection within these founder populations.
Using the population branch statistic (PBS), which has strong power to detect recent natural selection40 and has allowed us to investigate allele changes along specific branches, we identified another candidate example where cold adaptation may play a role. The FAM83H gene showed a signature of selection (top 99.9% PBS values) and was found to contain four fixed non-synonymous substitutions derived in the Antarctic lineages based on the inferred ancestral state, which resulted in physicochemical changes including a hydrophobic side chain being replaced by a positively charged side chain. The keratin-associated protein encoded by the FAM83H gene is thought to be important for skin development and regulation through regulation of the filamentous state of keratin within cytoskeletal networks in epithelial cells, determining processes such as cell migration and polarization41. Skin regeneration is thought to be constrained in killer whales while inhabiting the cold waters around Antarctica because of the high cost of heat loss, and is thought to underlie rapid round-trip movements to warmer subtropical waters by Antarctic ecotypes42. The balance between skin regeneration and thermal regulation in Antarctic waters could be a major selective force requiring both behavioural42 and genomic adaptation (Supplementary Fig. 15).
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