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Background: The primary aim of this study was to determine the epidemiology of lateral-end clavicle fractures in adolescents. The secondary aim was to assess the outcome following non-operative management. Methods: A retrospective review of all adolescent clavicle fractures over a 10-year period was undertaken. Fracture classification, demographics, management, and complications were analysed. Functional outcomes were undertaken with the Quick Disabilities of Arm, Shoulder and Hand and EuroQol five-dimension at mean 8.8 years post-injury. Results: In total, 677 clavicle fractures were analysed, 8.7% were lateral-end fractures (n = 59/677). The median age was 14.6 (range: 13-17) and 92% were male (n = 54/59). The incidence was 0.17 per 100,000 per year. All displaced physeal fractures (Neer IV n = 14) were managed non-operatively and of the six followed-up, all united with good outcomes. The adult type displaced fracture (Neer II) occurred in fifteen fractures, five underwent operative fixation and ten were managed non-operatively with one subsequent nonunion (n = 1/10). Those patients that underwent non-operative management (response n = 5/10, 50%) reported a median Quick Disabilities of Arm, Shoulder and Hand of 2.3 but approximately 40% reported cosmetic and outcome dissatisfaction at long-term follow-up. Conclusion: Displaced Neer II lateral-end clavicle fractures are rare in the adolescent population. Although nonunion is rare, some dissatisfaction with cosmesis persists at long-term follow-up despite good functional outcomes with non-operative management.
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Background Emergency "Anesthesia Stat!" (AS!) calls remain a common practice in medical centers even when advanced communication infrastructures are available. We hypothesize that the analysis of post-procedure "AS!" calls will lead to actionable insights which may enhance patient safety. Methods After institutional review board approval, we prospectively collected data from April 2015 through May 2018 on "AS!" calls throughout the pediatric operating rooms (OR), off-site locations, and post-anesthesia care unit (PACU) at a tertiary university medical center. Data recorded included demographic information, location, time of the event, event duration, vital signs, medications, anesthesia staff, attending anesthesiologist, and staff responding to the call. A narrative account of the event was also documented. Results A total of 82 "AS!" calls occurred, with ages ranging from 11 days old to 17 years old. Forty-nine of the 82 calls (60%) occurred at emergence. Seventy-one of the 82 calls (87%) were solely respiratory-related. Thirty-five of 49 emergence calls (71%) occurred in the PACU. Further, 34 of 35 PACU calls (97%) were respiratory-related, with 30 of 35 PACU calls (86%) associated with desaturation requiring intervention by anesthesia staff. Finally, 31 of 35 PACU calls (89%) occurred within 30 minutes of patient arrival to PACU. Conclusion Analysis of "AS!" events from our PACU continues to support the need for the prompt and continuous availability of at least one staff member with advanced airway management skills. Further, pediatric patients undergoing general anesthesia and surgery should likely be monitored for a minimum of 30 minutes following arrival in the PACU.
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Information on the potential ecological value of offshore oil and gas infrastructure is required as it reaches the end of its operational life and decisions must be made regarding the best practice option for decommissioning. This study uses baited remote underwater stereo-video systems to assess fish assemblages along an offshore subsea pipeline and in adjacent natural seabed habitats at â¼140â¯m depth on the North West Shelf of Western Australia. A total of 955 fish from 40 species and 25 families were recorded. Species richness was, on average 25% higher on the pipeline (6.48⯱â¯0.37 SE) than off (4.81⯱â¯0.28 SE) while relative abundance of fish was nearly double on the pipeline (20.38⯱â¯2.81 SE) than in adjacent natural habitats (10.97⯱â¯1.02 SE). The pipeline was characterised by large, commercially important species known to associate with complex epibenthic habitat and, as such, possessed a biomass of commercial fish ca 7.5 × higher and catch value ca. 8.6 × ($65.11⯱â¯$11.14 SE) than in adjacent natural habitats ($7.57⯱â¯$2.41 SE). This study has added to the knowledge of fish assemblage associations with subsea infrastructure and provides a greater understanding of the ecological and fisheries implications of decommissioning, helping to better inform decision-making on the fate of infrastructure.
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Explotaciones Pesqueras , Peces , Yacimiento de Petróleo y Gas , Animales , Ecosistema , Biología Marina , Australia OccidentalRESUMEN
The evidence base for the performance and effectiveness of non-structural measures to manage stormwater pollution in industrial areas is relatively underdeveloped, despite their increased use in practice. This study aims to advance stormwater management practice and research by presenting a detailed case study of the development, implementation and evaluation of a targeted behaviour change trial that engaged small to medium industrial businesses in stormwater pollution prevention. Utilising a combination of different behaviour change strategies - including capacity building, social norms and commitment - a number of preventative stormwater pollution behaviours were changed in participating businesses. Our study provides a practice model for tackling stormwater pollution from a behavioural perspective that can be further developed by both practitioners and researchers to create effective and long-lasting change.
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Contaminación Ambiental/prevención & control , Monitoreo del Ambiente , Industrias/normas , LluviaRESUMEN
Analysis of the periodic points of a conservative periodic dynamical system uncovers the basic kinematic structure of the transport dynamics and identifies regions of local stability or chaos. While elliptic and hyperbolic points typically govern such behaviour in 3D systems, degenerate (parabolic) points also play an important role. These points represent a bifurcation in local stability and Lagrangian topology. In this study, we consider the ramifications of the two types of degenerate periodic points that occur in a model 3D fluid flow. (1) Period-tripling bifurcations occur when the local rotation angle associated with elliptic points is reversed, creating a reversal in the orientation of associated Lagrangian structures. Even though a single unstable point is created, the bifurcation in local stability has a large influence on local transport and the global arrangement of manifolds as the unstable degenerate point has three stable and three unstable directions, similar to hyperbolic points, and occurs at the intersection of three hyperbolic periodic lines. The presence of period-tripling bifurcation points indicates regions of both chaos and confinement, with the extent of each depending on the nature of the associated manifold intersections. (2) The second type of bifurcation occurs when periodic lines become tangent to local or global invariant surfaces. This bifurcation creates both saddle-centre bifurcations which can create both chaotic and stable regions, and period-doubling bifurcations which are a common route to chaos in 2D systems. We provide conditions for the occurrence of these tangent bifurcations in 3D conservative systems, as well as constraints on the possible types of tangent bifurcation that can occur based on topological considerations.
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Mixing of materials is fundamental to many natural phenomena and engineering applications. The presence of discontinuous deformations-such as shear banding or wall slip-creates new mechanisms for mixing and transport beyond those predicted by classical dynamical systems theory. Here, we show how a novel mixing mechanism combining stretching with cutting and shuffling yields exponential mixing rates, quantified by a positive Lyapunov exponent, an impossibility for systems with cutting and shuffling alone or bounded systems with stretching alone, and demonstrate it in a fluid flow. While dynamical systems theory provides a framework for understanding mixing in smoothly deforming media, a theory of discontinuous mixing is yet to be fully developed. New methods are needed to systematize, explain, and extrapolate measurements on systems with discontinuous deformations. Here, we investigate "webs" of Lagrangian discontinuities and show that they provide a template for the overall transport dynamics. Considering slip deformations as the asymptotic limit of increasingly localised smooth shear, we also demonstrate exactly how some of the new structures introduced by discontinuous deformations are analogous to structures in smoothly deforming systems.
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Modelos Teóricos , Reología , Dinámicas no LinealesRESUMEN
As corticosteroid-sparing protocols are increasingly utilized in kidney transplant recipients, it is crucial to understand potential drug interactions between tacrolimus (TAC) and the effect of corticosteroid withdrawal as well as to characterize dose adjustments of mycophenolate mofetil (MMF) in this setting. This prospective, multicenter, randomized, double-blind study included 397 patients who were randomized on posttransplant day 8 to receive either placebo (CSWD) or corticosteroid continuance (CCS). TAC trough levels at week two posttransplant were significantly greater in the CSWD group whereas TAC doses were comparable to the CCS group. This interaction was not observed in the African American subgroup. Higher serum creatinine and potassium levels were also observed in the CSWD group. MMF dose was significantly reduced in the CSWD group by the investigators because of decreased WBC counts, mostly outside of study protocol criteria, despite similar incidence of neutropenia and reported cytomegalovirus infection. Understanding TAC and MMF exposure in the context of corticosteroid-sparing protocols should allow for improved dosing of immunosuppressants and better management of posttransplant patients.
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Corticoesteroides/uso terapéutico , Trasplante de Riñón/métodos , Ácido Micofenólico/análogos & derivados , Insuficiencia Renal/terapia , Tacrolimus/administración & dosificación , Adulto , Negro o Afroamericano , Índice de Masa Corporal , Método Doble Ciego , Femenino , Humanos , Hiperpotasemia/metabolismo , Masculino , Persona de Mediana Edad , Ácido Micofenólico/administración & dosificación , Estudios Prospectivos , Insuficiencia Renal/etnologíaRESUMEN
Young children are at increased risk for valproic acid (VPA) hepatotoxicity. Urinary organic acid profiles, as a surrogate of mitochondrial function, were obtained in children 1.9 to 17.3 years of age (n = 52) who were undergoing treatment with VPA for seizure disorders. Age-matched patients receiving treatment with carbamazepine (CBZ; n = 50) and healthy children not undergoing treatment (n = 22) served as controls. Age-related changes in organic acid profiles were observed in all three groups. Although the untreated and CBZ control groups were indistinguishable from each other with respect to the principal-component analysis (PCA) score plots of the subjects, a distinct boundary was apparent between the VPA and each of the control groups. Interindividual variability was observed in the VPA-induced alterations in endogenous pathways corresponding to branched-chain amino acid metabolism and oxidative stress. The data suggest that more detailed metabolomic analysis may provide novel insights into biological mechanisms and predictive biomarkers for children at highest risk for serious toxicity.
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Ácidos Carboxílicos/orina , Metaboloma/efectos de los fármacos , Metaboloma/fisiología , Ácido Valproico/metabolismo , Ácido Valproico/farmacología , Adolescente , Factores de Edad , Niño , Preescolar , Femenino , Humanos , Lactante , Ácido Láctico/orina , Masculino , Análisis de Componente Principal , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Knowing a young woman with newly diagnosed breast cancer has a germline BRCA1 mutation informs her clinical management and that of her relatives. We sought an optimal strategy for identifying carriers using family history, breast cancer morphology and hormone receptor status data. METHODS: We studied a population-based sample of 452 Australian women with invasive breast cancer diagnosed before age 40 years for whom we conducted extensive germline mutation testing (29 carried a BRCA1 mutation) and a systematic pathology review, and collected three-generational family history and tumour ER and PR status. Predictors of mutation status were identified using multiple logistic regression. Areas under receiver operator characteristic (ROC) curves were estimated using five-fold stratified cross-validation. RESULTS: The probability of being a BRCA1 mutation carrier increased with number of selected histology features even after adjusting for family history and ER and PR status (P<0.0001). From the most parsimonious multivariate model, the odds ratio for being a carrier were: 9.7 (95% confidence interval: 2.6-47.0) for trabecular growth pattern (P=0.001); 7.8 (2.7-25.7) for mitotic index over 50 mitoses per 10 high-powered field (P=0.0003); and 2.7 (1.3-5.9) for each first-degree relative with breast cancer diagnosed before age 60 years (P=0.01).The area under the ROC curve was 0.87 (0.83-0.90). CONCLUSION: Pathology review, with attention to a few specific morphological features of invasive breast cancers, can identify almost all BRCA1 germline mutation carriers among women with early-onset breast cancer without taking into account family history.
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Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Carcinoma/genética , Carcinoma/patología , Genes BRCA1 , Mutación de Línea Germinal , Adulto , Factores de Edad , Neoplasias de la Mama/diagnóstico , Carcinoma/diagnóstico , Análisis Mutacional de ADN , Salud de la Familia , Femenino , Estudio de Asociación del Genoma Completo , Heterocigoto , Humanos , Pronóstico , Sistema de Registros , Estudios Retrospectivos , Carga Tumoral , MujeresRESUMEN
OBJECTIVE: Chromosomal loss within the region of 18q and loss of SMAD4 expression have been reported to be frequent somatic events during colorectal cancer tumour progression; however, their associations with age at onset have not been widely studied. METHOD: We analysed 109 tumours from a population-based case-family study based on colorectal cancers diagnosed before the age of 45 years. These patients with early-onset colorectal cancer had been previously screened for germ-line mismatch repair gene mutations, microsatellite instability (that included the mononucleotide repeat in TGFbetaRII) and somatic k-ras mutations. We measured SMAD4 protein expression using immunohistochemistry and SMAD4 copy number using quantitative real-time PCR. RESULTS: Loss of SMAD4 protein expression was observed in 27/109 (25%) of cancers tested and was more commonly observed in rectal tumours (15/41, 36%) when compared with tumours arising in the colon (11/66, 17%) (P = 0.04). There was no association between SMAD4 protein expression and TGFbetaR11 mutation status, SMAD4 copy number, family history, MSI status, tumour stage or grade. CONCLUSION: Loss of SMAD4 expression is a common feature of early-onset colorectal tumours as it is in colorectal cancers diagnosed in other age-groups. Taken together, the molecular pathways (genetic and epigenetic) now known to be involved in early-onset colorectal cancer only explain a small proportion of the disease and require further exploration.
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Adenocarcinoma/metabolismo , Neoplasias Colorrectales/metabolismo , Proteína Smad4/metabolismo , Adenocarcinoma/genética , Adolescente , Adulto , Neoplasias Colorrectales/genética , Variaciones en el Número de Copia de ADN , Femenino , Humanos , Masculino , Proteína Smad4/genética , Adulto JovenRESUMEN
Women diagnosed with breast cancer before the age of 40 years who have a strong family history of breast and/or ovarian cancer were selected from an Australian population-based case-control-family study for large deletion screening within the BRCA1 promoter. Deletions within the BRCA1 promoter region are usually not detected by the methods applied in routine clinical mutation detection strategies. Fifty-one of the 66 women (77%) who met our inclusion criteria were tested for promoter deletions using linkage disequilibrium analysis of two BRCA1 polymorphic sites (C/G1802 and Pro871Leu) and multiplex ligation-dependent probe amplification. Two cases of BRCA1 promoter deletion involving exons 1A-2 and exons 1A-23 were detected. The morphology of the breast cancers arising in these women with BRCA1 promoter deletions was consistent with the morphology associated with other germline BRCA1 mutations. Large genomic deletions that involve the promoter regions of BRCA1 make up 20% (2/10) of all known BRCA1 mutations in this group of young women with a strong family history of breast and ovarian cancer. Our data support the inclusion of testing for large genomic alterations in the BRCA1 promoter region in routine clinical mutation detection within BRCA1.
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Neoplasias de la Mama/genética , Eliminación de Gen , Genes BRCA1 , Regiones Promotoras Genéticas/genética , Adulto , Femenino , Predisposición Genética a la Enfermedad/genética , Genotipo , Humanos , LinajeRESUMEN
Understanding the pattern of connectivity among populations is crucial for the development of realistic and spatially explicit population models in marine systems. Here we analysed variation at eight microsatellite loci to assess the genetic structure and to infer patterns of larval dispersal for a brooding coral, Seriatopora hystrix, at an isolated system of reefs in northern Western Australia. Spatial autocorrelation analyses show that populations are locally subdivided, and that the majority of larvae recruit to within 100 m of their natal colony. Further, a combination of F- and R- statistics showed significant differentiation at larger spatial scales (2-60 km) between sites, and this pattern was clearly not associated with distance. However, Bayesian analysis demonstrated that recruitment has been supplemented by less frequent but recent input of larvae from outside the local area; 2-6% of colonies were excluded from the site at which they were sampled. Individual assignments of these migrants to the most likely populations suggest that the majority of migrants were produced at the only site that was not decimated by a recent and catastrophic coral bleaching event. Furthermore, the only site that recovered to prebleaching levels received most of these immigrants. We conclude that the genetic structure of this brooding coral reflects its highly opportunistic life history, in which prolific, philopatric recruitment is occasionally supplemented by exogenously produced larvae.
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Antozoos/genética , Demografía , Desastres , Variación Genética , Genética de Población , Animales , Teorema de Bayes , Frecuencia de los Genes , Geografía , Océano Índico , Repeticiones de Microsatélite/genética , Modelos Genéticos , Dinámica Poblacional , Australia OccidentalRESUMEN
Clinical and electrophysiologic findings on 136 patients (39 women and 97 men; mean age = 33.2 years) with traumatic peripheral nerve injuries were reviewed. Motor vehicular collisions (MVCs) caused 39.7% and gunshot wounds (GSWs) produced 32.4% of the nerve injuries studied. Other factors such as falls, lacerations, work-related injuries, knife wounds, and blunt traumas produced the remaining 27.9% of the nerve injuries in the study group. Peripheral nerves of the upper limbs (79.6%) were disproportionately damaged in MVCs compared with those of the lower limbs (20.4 %). In MVCs, the brachial plexus was involved in 37.0% and radial nerve in 22.2% of the cases. Patients with GSWs were predominantly men (88.6%) and slightly younger (mean age = 28.7 years). The frequencies of peripheral nerve injuries to the upper extremities (52.3%) and lower extremities (45.5%) were nearly similar in GSWs. The sciatic nerve was involved in 34.1% of GSWs, followed by the ulnar nerve (22.7%).
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Traumatismos de los Nervios Periféricos , Accidentes de Trabajo , Accidentes de Tránsito , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neurofisiología , Heridas no Penetrantes/complicaciones , Heridas Penetrantes/complicacionesRESUMEN
Inshore coral reefs adjacent to the wet tropics in North Queensland, Australia, are regularly exposed to flood plumes from coastal river systems. Changes in the nature of these plumes have been linked to the declining health of coral reefs in the region. The effect of flood plumes on the health of inshore corals was investigated by quantifying aspects of the demography of populations of corymbose and digitate Acropora at three groups of Island reefs along a gradient of exposure and decreasing water quality (High Island >Frankland's >Fitzroy). The size-structures of colonies, the rates of sexual recruitment, and the growth and survival of juveniles, all varied among the Island reefs. Juvenile and adult sized colonies were far more abundant at the Fitzroy Island reefs, than at the High or Frankland Island reefs that were more exposed to flood plumes. Additionally, there were up to eight times as many sexual recruits at the Fitzroy Island reefs, compared with the High Island reefs. However, the rates of growth and survival of the juvenile sized corals at the Fitzroy Island reefs were lower than at the more exposed reefs. The comparatively low abundance of adult corals at the exposed reefs is most likely due to their histories of disturbance from crown-of-thorns and coral bleaching, but the lack of subsequent recovery due to their low levels of larval recruitment. If a stock-recruitment relationship is typical for these groups of reefs, then the low rates of recruitment may be linked to the low density of adult colonies. Alternately, direct or indirect effects of chronic exposure to poor water quality may have resulted in less suitable substrata for larval settlement. We discuss these results and provide examples of how information about population structure and dynamics can be used in simple matrix models to quantify the current and future health of populations of corals under various scenarios.
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Antozoos/crecimiento & desarrollo , Monitoreo del Ambiente/métodos , Razón de Masculinidad , Animales , Ecosistema , Femenino , Larva/crecimiento & desarrollo , Masculino , Dinámica Poblacional , Queensland , Análisis de Supervivencia , Clima TropicalAsunto(s)
Ciclosporina/efectos adversos , Trasplante de Riñón/inmunología , Tacrolimus/uso terapéutico , Adolescente , Niño , Preescolar , Creatinina/sangre , Femenino , Rechazo de Injerto/epidemiología , Humanos , Inmunosupresores/efectos adversos , Inmunosupresores/uso terapéutico , Trasplante de Riñón/fisiología , Masculino , Registros Médicos , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/uso terapéutico , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Right sided endocarditis usually involves the tricuspid valve, predominantly in intravenous drug users. It is also occasionally acquired in hospital as a result of contaminated intravascular devices. Isolated infection of the pulmonary valve is rarely seen. A case of community acquired Staphylococcus aureus pulmonary valve endocarditis that caused diagnostic confusion is reported. This infection occurred in a patient with no history of intravenous drug abuse and a previously structurally normal heart.
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Endocarditis Bacteriana/tratamiento farmacológico , Válvula Pulmonar , Infecciones Estafilocócicas/complicaciones , Adulto , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/microbiología , Farmacorresistencia Bacteriana Múltiple , Endocarditis Bacteriana/microbiología , Humanos , Masculino , Staphylococcus aureusRESUMEN
BACKGROUND: Traditional resuscitation regimens have been recently challenged. This study evaluates hypotensive resuscitation with a hemoglobin-based oxygen-carrying (HBOC) solution after severe hemorrhage in a porcine model. We hypothesized that HBOC-201 restores tissue perfusion at a lower mean arterial pressure than standard resuscitation fluids. METHODS: Yorkshire swine (55-65 kg, n = 30), were rapidly hemorrhaged to a mean arterial pressure (MAP) of 30 mm Hg, maintained hypotensive for 45 minutes, and randomized into groups. Group I was resuscitated with an HBOC solution to a MAP of 60 mm Hg. Groups II and III were resuscitated to a MAP of 80 mm Hg with lactated Ringer's solution (LR) alone or LR (40 mL/kg) followed by shed blood, respectively. Group IV was resuscitated with shed blood alone to a MAP of 60 mm Hg. Group V received an HBOC solution to a MAP of 50 mm Hg. Hemodynamic variables, Swan-Ganz parameters, blood gas samples, and lactate levels were followed for 5 hours. Data were analyzed by analysis of variance/Duncan multiple range test. RESULTS: There were no significant differences in mortality between any groups. Groups I, IV, and V had lower (p < 0.05) cardiac output, pulmonary artery wedge pressure, and MAP than either group II or group III. Svo2 was significantly lower in the HBOC groups. There were no significant differences in arterial pH or lactate between groups I, III, and IV. Lactate levels, base excess, and arterial pH were significantly worse in the LR-alone and HBOC-50 groups. CONCLUSION: Hypotensive resuscitation with HBOC-201 at a MAP of 60 mm Hg after a controlled hemorrhage in swine provides sufficient tissue perfusion and oxygen delivery to reverse anaerobic metabolism on the basis of global physiologic markers despite continued hypotension, hypovolemia, and low cardiac output.
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Sustitutos Sanguíneos/farmacología , Hemorragia/terapia , Hipotensión/terapia , Resucitación/métodos , Análisis de Varianza , Animales , Análisis de los Gases de la Sangre , Hemoglobinas , Hemorragia/fisiopatología , Concentración de Iones de Hidrógeno , Hipotensión/fisiopatología , Ácido Láctico/sangre , Presión Esfenoidal Pulmonar , Volumen Sistólico , PorcinosRESUMEN
Since the early 19th century, graphs have been recognised as an effective method of analysing and representing scientific data. However, levels of graph use have varied widely since then, partly due to increasing reliance on inferential statistics in some fields. Recent studies indicate that graph use is closely related to the 'hardness' of scientific disciplines, and that this finding holds for journal articles and textbooks across the subfields of psychology. In the area of animal behaviour, journals devote about one-sixth of their page space to graphs, a level of graph use approximating that of biology and physics. Implications for the training of scientists in the use of visual displays are considered.
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Although the fledgling psychology of 100 years ago was assertively empirical, there were no inferential statistics to guide psychologists' data analyses. However, 19th-century developments had left psychology with a rich array of techniques for analyzing and presenting data, some of which remain underutilized today. These include comparisons across replications, within-subject designs, reanalysis of data, analyses of factorial designs, and especially the use of tables and graphs. As the merits of hypothesis-testing statistics are debated at the turn of the 21st century, the history of data-handling practices can remind psychologists that there are many ways to overcome the current uniformity of statistical practice.
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Interpretación Estadística de Datos , Psicología/historia , Historia del Siglo XIX , Historia del Siglo XX , Humanos , Edición/historia , Estadística como Asunto/historia , Estados UnidosRESUMEN
The expression of defensive morphologies in prey often is correlated with predator abundance or diversity over a range of temporal and spatial scales. These patterns are assumed to reflect natural selection via differential predation on genetically determined, fixed phenotypes. Phenotypic variation, however, also can reflect within-generation developmental responses to environmental cues (phenotypic plasticity). For example, water-borne effluents from predators can induce the production of defensive morphologies in many prey taxa. This phenomenon, however, has been examined only on narrow scales. Here, we demonstrate adaptive phenotypic plasticity in prey from geographically separated populations that were reared in the presence of an introduced predator. Marine snails exposed to predatory crab effluent in the field increased shell thickness rapidly compared with controls. Induced changes were comparable to (i) historical transitions in thickness previously attributed to selection by the invading predator and (ii) present-day clinal variation predicted from water temperature differences. Thus, predator-induced phenotypic plasticity may explain broad-scale geographic and temporal phenotypic variation. If inducible defenses are heritable, then selection on the reaction norm may influence coevolution between predator and prey. Trade-offs may explain why inducible rather than constitutive defenses have evolved in several gastropod species.