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Other Explanations (other + explanation)
Selected AbstractsTWO SNOW SPECIES OF THE QUADRIFLAGELLATE GREEN ALGA CHLAINOMONAS (CHLOROPHYTA, VOLVOCALES): ULTRASTRUCTURE AND PHYLOGENETIC POSITION WITHIN THE CHLOROMONAS CLADE,JOURNAL OF PHYCOLOGY, Issue 4 2008Philip M. Novis The quadriflagellate snow alga Chlainomonas Christen, distributed in New Zealand and North America, has several unusual structural attributes. A process assumed to be cytokinesis involves extrusion of protoplasm from the parent through a narrow canal, C. kolii (J. T. Hardy et Curl) Hoham produces a net-like outer envelope rather than a cell wall, and the flagellar basal apparatus of Chlainomonas consists of two semi-independent pairs of basal bodies. Structural connections between basal body pairs appear minimal, but a connecting system different from that observed in other genera exists within each pair. Phylogenetic analysis using rbcL sequences places Chlainomonas in the Chloromonas clade, other known members of which are all biflagellate. Chlainomonas is split into two robust lineages, with New Zealand collections sharing an origin with northern North American collections. Although the quadriflagellate condition is regarded as ancestral in the Chlorophyceae, we speculate,based on ultrastructural and molecular data presented here,that Chlainomonas represents a derived form that has arisen from fusion of two ancestral biflagellate cells. Other explanations (for example, that Chlainomonas represents a diploid form of a biflagellate species) are remotely possible but are presently at odds with extensive observations of field material. Improvements in techniques for experimental manipulation of these sensitive cryophiles will be required to fully characterize their structure and progress our understanding of their biology. [source] Increasing incidence of differentiated thyroid cancer in the United States, 1988,2005CANCER, Issue 16 2009Amy Y. Chen MD Abstract BACKGROUND: Studies have reported an increasing incidence of thyroid cancer since 1980. One possible explanation for this trend is increased detection through more widespread and aggressive use of ultrasound and image-guided biopsy. Increases resulting from increased detection are most likely to involve small primary tumors rather than larger tumors, which often present as palpable thyroid masses. The objective of the current study was to investigate the trends in increasing incidence of differentiated (papillary and follicular) thyroid cancer by size, age, race, and sex. METHODS: Cases of differentiated thyroid cancer (1988-2005) were analyzed using the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) dataset. Trends in incidence rates of papillary and follicular cancer, race, age, sex, primary tumor size (<1.0 cm, 1.0-2.9 cm, 3.0-3.9 cm, and >4 cm), and SEER stage (localized, regional, distant) were analyzed using joinpoint regression and reported as the annual percentage change (APC). RESULTS: Incidence rates increased for all sizes of tumors. Among men and women of all ages, the highest rate of increase was for primary tumors <1.0 cm among men (1997-2005: APC, 9.9) and women (1988-2005: APC, 8.6). Trends were similar between whites and blacks. Significant increases also were observed for tumors ,4 cm among men (1988-2005: APC, 3.7) and women (1988-2005: APC, 5.70) and for distant SEER stage disease among men (APC, 3.7) and women (APC, 2.3). CONCLUSIONS: The incidence rates of differentiated thyroid cancers of all sizes increased between 1988 and 2005 in both men and women. The increased incidence across all tumor sizes suggested that increased diagnostic scrutiny is not the sole explanation. Other explanations, including environmental influences and molecular pathways, should be investigated. Cancer 2009. © 2009 American Cancer Society. [source] Lymphoid bronchiolitis presenting at birth in an immunocompetent child: Chronic interstitial lung disease of unknown aetiologyPEDIATRIC PULMONOLOGY, Issue 6 2009Malcolm Brodlie MB ChB Abstract A female infant presented at birth with respiratory distress, which was subsequently shown to be secondary to lymphoid bronchiolitis, an exceptionally rare condition in childhood. Over the following 13 years there has been a slow progressive deterioration in her respiratory status with forced expiratory volume in 1 sec currently 40% predicted. Tests for connective tissue disease, infection, or immunodeficiency have all been negative and in the absence of any other explanation we postulate that this severe problem may have occurred as a consequence of an unrecognized intrauterine infection. Pediatr Pulmonol. 2009; 44:622,624. © 2009 Wiley-Liss, Inc. [source] Prison staff and women prisoner's views on self-harm; their implications for service delivery and development: A qualitative studyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 4 2010Cassandra Kenning Background,Rates of self-harm are high among women in prison in the UK. This is the first study to compare the views and attitudes of prison staff and women prisoners and to look at the effects of these attitudes on prisoner/staff relationships. Aims,To explore understanding of self-harm among women prisoners, prison officers and health-care staff and how their perceptions might influence service provision and development. Method,Semi-structured interviews were conducted with women prisoners who self-harm and with staff at a women's prison. Data were analysed thematically. Results,Prison officers often attributed motives to self-harm such as ,manipulation' and ,attention-seeking', whereas descriptions by women prisoners, prison governors and health-care staff suggested explanations in affect regulation or self-punishment. Conclusions,Differences between prison officers and other staff working in the prison in their understanding of self-harm by women prisoners may lie in training differences, but there may be other explanations such as self-protection/coping strategies. More training and support for officers may result in improved staff,prisoner relationships and thus, safer service provision. Copyright © 2010 John Wiley & Sons, Ltd. [source] Patterns of commonness and rarity in central European birds: reliability of the core-satellite hypothesis within a large scaleECOGRAPHY, Issue 4 2002David Storch The frequency distribution of species' area of occupancy is often bimodal, most species being either very rare or very common in terms of number of occupied sites. This pattern has been attributed to the nonlinearity associated with metapopulation dynamics of the species, but there are also other explanations comprising sampling artifact and frequency distribution of suitable habitats. We tested whether the bimodal frequency distribution of occupied squares in central European birds could be derived solely from the frequency distribution of species population sizes (i.e. the sampling artifact hypothesis) or from the spatial distribution of their preferred habitats. Both models predict high proportion of very common species, i.e. the right side of frequency distribution. Bimodality itself is well predicted by models based on random placement of individuals according to their abundances but neither model predicts the observed prevalence of rare species. Even the combined models that assume random placement of individuals within the squares with suitable habitat do not predict such a high proportion of rare species. The observed distribution is more aggregated, rare species occupying a smaller portion of suitable habitat than predicted on the basis of their abundance. The pattern is consistent with metapopulation processes involving local population extinctions. The involvement of these processes is supported by two further observations. First, species rarity is associated with significant population trend and/or location on the edge of their ranges within central Europe, both situations presumably associated with metapopulation processes. Second, suitable habitats seem to be either saturated or almost unoccupied, which is consistent with the predictions of the metapopulation model based on nonlinear dynamics of extinction and colonization. Although the habitat suitability is an important determinant of species distribution, the rarity of many species of birds within this scale of observation seems to be affected by other factors, including local population extinctions associated with fragmentation of species' habitats. [source] Evaluating theories of alcohol-related aggression using observations of young adults in barsADDICTION, Issue 6 2000Kathryn Graham Aims. The objective of the present study is to evaluate 36 explanations of alcohol-related aggression that have been proposed in the research literature in terms of their relevance to naturally-occurring incidents of aggression involving alcohol. Design. The study involved content analysis of descriptions of 105 incidents of aggression. Setting and participants. Bars frequented by young adults. Measurements. Step-by-step descriptions of incidents of aggression reported by researcher-observers based on 93 nights of observation in bars between midnight and 3 a.m. Findings. Some explanations relating to the effects of alcohol (e.g. focused on the present, reduced anxiety about sanctions or danger, heightened emotionality) and the environment (e.g. generally permissive environment, expectation by patrons that aggression will be tolerated) were found to be relevant to most incidents, while other explanations (e.g. crowding, release of pent-up anger) were directly relevant to only a few or no incidents. Incidents involving male-to-male aggression were more likely than incidents involving both males and females to be attributable to expectations, acceptance of aggression, power concerns, male honor and "macho" values. Principal components analysis identified five groupings of explanations: risk-taking effects of alcohol, cognitive impairment from alcohol, hyperemotional effects of alcohol, "macho" subculture, and permissive environment. Conclusions. The findings are consistent with a model of alcohol-related aggression that involves multiple contributing factors including alcohol effects and situational contexts. The greater relevance of certain explanations and the natural groupings of explanations point to directions for future research. [source] Seismic evidence for a sharp lithospheric base persisting to the lowermost mantle beneath the CaribbeanGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2008Tadashi Kito SUMMARY Broad-band data from South American earthquakes recorded by Californian seismic networks are analysed using a newly developed seismic wave migration method,the slowness backazimuth weighted migration (SBWM). Using the SBWM, out-of-plane seismic P -wave reflections have been observed. The reflection locations extend throughout the Earth's lower mantle, down to the core,mantle boundary (CMB) and coincide with the edges of tomographically mapped high seismic velocities. Modelling using synthetic seismograms suggests that a narrow (10,15 km) low- or high-velocity lamella with about 2 per cent velocity contrast can reproduce the observed reflected waveforms, but other explanations may exist. Considering the reflection locations and synthetic modelling, the observed out-of-plane energy is well explained by underside reflections off a sharp reflector at the base of the subducted lithosphere. We also detect weaker reflections corresponding to the tomographically mapped top of the slab, which may arise from the boundary between the Nazca plate and the overlying former basaltic oceanic crust. The joint interpretation of the waveform modelling and geodynamic considerations indicate mass flux of the former oceanic lithosphere and basaltic crust across the 660 km discontinuity, linking processes and structure at the top and bottom of the Earth's mantle, supporting the idea of whole mantle convection. [source] Case Report: Atheroembolic renal disease in a 72-year-old patient through coronary intervention after myocardial infarctionHEMODIALYSIS INTERNATIONAL, Issue 4 2008Anna Laura HERZOG Abstract Cholesterol embolization or atheroembolic renal disease (AERD) is an often underdiagnosed issue in patients featuring a prevalent risk profile. It is a multisystemic disease with progressive renal insufficiency due to foreign body reaction of cholesterol crystals flushed into a small vessel system of the kidneys from the arteriosclerotic plaques. The most common setting in which it occurs is iatrogenic after vascular catheterization and less frequent spontaneously. Typical clinical symptoms are delayed impairment of renal function, cutaneous manifestations such as livedo reticularis or purple toes with persistingly palpable arterial pulse, myalgia, systemic symptoms such as weight loss and fever, and abdominal and neurological symptoms. Diagnosis is generally made by clinical appearance, risk profile, and interval of time from intervention; a definitive diagnosis can only be made by renal biopsy. Even though the exact incidence is not known because most patients do not undergo biopsy due to older age, comorbidity, and other explanations for loss of renal function, it is estimated to be 4% after vascular intervention. Patient and renal outcome is dependent on comorbidity, risk profile, and preexisting chronic kidney disease (CKD). About 30% of patients are estimated to require maintenance dialysis and these patients have a high risk of death within 24 months after the first renal replacement therapy. Prognosis is also influenced by severity. The case reported is a 72-year-old male patient with preexisting CKD stage 3 undergoing percutaneous coronary intervention after myocardial infarction and consecutive AERD with typical clinical appearance 6 weeks after the event. [source] Teaching & Learning Guide for: The Origins of the Civil WarHISTORY COMPASS (ELECTRONIC), Issue 4 2007Nicole Etcheson Author's Introduction The author argues that slavery is the root cause of the Civil War even though historians have often posited other explanations. Some other interpretations have been ideological (i.e., about the morality of slavery), others have been economic, political, or cultural. Focus Questions 1If you were to make an argument for the causes of the Civil War, what evidence or types of evidence would you want to examine? 2In what ways can the different types of arguments (ideological, economic, political, and cultural), be combined to explain the causes of the Civil War? Do such arguments exclude or reinforce each other? In what ways? Author Recommends * E. L. Ayres, In the Presence of Mine Enemies: War in the Heart of America, 1859,1863 (New York, NY: Norton, 2003). A study of two counties, one north and one south, during the end of the sectional crisis and the early Civil War. While Potter, Walther, and Wilentz offer sweeping, often political, histories, Ayres offers a microhistory approach to the sectional conflict. Although Ayres writes within the tradition of seeing cultural differences between North and South, he concludes that slavery was the issue that drove the two sections apart. * M. A. Morrison, Slavery and the American West: The Eclipse of Manifest Destiny and the Coming of the Civil War (Chapel Hill, NC: University of North Carolina Press, 1997). Views the development of the sectional crisis through the lens of Manifest Destiny. Territorial expansion drove hostility between the sections. Morrison concentrates on the political developments of the period connected to the acquisition and organization of the territories to show how the issue of slavery in the territories polarized the sections. * D. M. Potter, The Impending Crisis, 1848,1861 (New York, NY: Harper & Row, 1976). The most comprehensive survey of the decade before the war. Potter traces the development of slavery as a political issue that North and South could not resolve. While it is a masterly and nuanced treatment of the political history, it does not incorporate social history and is more detailed than is useful for most undergraduates. E. H. Walther, The Shattering of the Union: America in the 1850s (Wilmington, Scholarly Resources, 2004) has recently supplanted Potter as a survey of the decade. It is an easier read for undergraduates and incorporates the new literature than has emerged since Potter wrote. * S. Wilentz, The Rise of American Democracy: Jefferson to Lincoln (New York, NY: Norton, 2005). A sweeping history of the United States from the constitutional era to the outbreak of the Civil War. Wilentz attempts to update Arthur M. Schlesinger Jr.'s synthesis The Age of Jackson by returning to a focus on the evolution of democracy while at the same time incorporating the social history that emerged after Schlesinger wrote. Only the last third of this very long book covers the 1850s, but Wilentz argues that democracy had taken differing sectional forms by that period: a free-labor version in the North and a plantation version in the South. Online Materials 1. The Valley of the Shadow: Two Communities in the American Civil War (http://valley.vcdh.virginia.edu/) A prize-winning website that profiles Augusta County, Virginia and Franklin County, Pennsylvania. Material from this website formed the basis of Ayres, In the Presence of Mine Enemies. Although the website primarily concentrates on the Civil War itself, it provides access to newspapers and letters and diaries from the 1850s that show the development of, and reaction to, the sectional crisis in those counties. It also shows students the types of materials (census, tax, and church records as well as newspapers and letters and diaries) with which historians work to build an argument. 2. American Memory from the Library of Congress (http://memory.loc.gov/ammem/index.html) Although not specifically devoted to the origins of the Civil War, the American Memory site provides access to the collections of the Library of Congress which contain massive amounts of primary materials for students and scholars. From the website, one can gain access to congressional documents, periodicals from the 1850s, nineteenth-century books, music, legal documents, memoirs by white and black southerners as well as slave narratives. Sample Syllabus Nicole Etcheson's ,Origins of the Civil War,' History Compass, 3/1 (2005), doi:10.1111/j.1478-0542.2005.00166.x can be used as a reading in any Civil War course. [source] Male and female Silene latifolia plants differ in per-contact risk of infection by a sexually transmitted diseaseJOURNAL OF ECOLOGY, Issue 1 2001Oliver Kaltz Summary 1,Behavioural, physiological or immunological constraints often render one sex more susceptible to parasites, thereby potentially generating sex-specific trade-offs between traits associated with infection risk and other life-history characters. 2,The fungal pathogen Microbotryum violaceum systemically infects the dioecious plant Silene latifolia when pollinators deposit fungal spores on the flowers of healthy plants. Male plants produce many short-lived flowers, whereas females produce few flowers that remain connected with the plant after fertilization. We investigated how variation in flower production and flower longevity affects the infection risk for males and females. 3,In glasshouse experiments, we varied the number of flowers inoculated (4 vs. 16 per plant) with spores and the time until these flowers were removed (1 or 2 days for both sexes, 14 days for females only). We also measured the longevity of male flowers receiving simulated visits, with or without spores, to test for an abscission response to visitation and/or contamination. In a field survey, we measured male and female disease prevalence in 17 natural populations. 4,Varying the number of inoculated flowers did not affect infection probability, but females retaining inoculated flowers for 14 days became diseased more often (20.0%) than did plants with flowers removed within 2 days (7.3%). 5,Males that had dropped more inoculated flowers prematurely were more likely to remain uninfected. Spore-bearing visits shortened male flower longevity (38.4 ± 2.8 h) relative to non-spore visits (47.9 ± 5.2 h). 6,Female field disease prevalence (19.7 ± 3.5%) was higher than that of males (14.3 ± 2.6%), especially in populations with a high disease incidence. 7,Continuing physical connection during fruit ripening appears to increase invasion time and thus the per-contact infection risk in females. This is consistent with higher female field prevalences, although other explanations, unrelated to disease transmission, are possible. These results illustrate how interactions between plant reproductive behaviour and pollinator activity may affect disease spread. Female mating behaviour may evolve towards lower attractiveness to pollinators to minimize infectious contacts, while males can afford to be more promiscuous with an attractive, but disposable, floral display. [source] Low risk of contrast-medium-induced nephropathy with modern angiographic techniqueJOURNAL OF INTERNAL MEDICINE, Issue 5 2001G. Sterner Abstract.,Sterner G, Nyman U, Valdes T (Malmö University Hospital, Malmö, Sweden). Low risk of contrast-medium-induced nephropathy with modern angiographic technique. J Intern Med 2001; 250: 429,434. Objective and design.,A retrospective study of the incidence of contrast-medium-induced nephropathy (CMN) in patients with renal insufficiency. Subjects.,All angiographies with and without endovascular therapeutic procedures (n=2400) performed at the hospital during 1 year were evaluated. A total of 139 patients were found to have a preangiographic serum-creatinine (s-Cr) of 150 ,mol L,1 or above. Postprocedural serial s-Cr values were present in 118 patients and these were included in the study. Results.,Amongst patients receiving only iodinated contrast media (CM) 8% demonstrated a 25% rise in s-Cr. The corresponding figure was 11 and 12.5% amongst patients who were given either iodinated CM together with carbon dioxide (CO2) or CO2 as sole contrast medium. After exclusion of other explanations of impaired renal function all together only seven of 114 patients (6%) were considered to have developed CMN. Four of the seven patients restituted renal function completely, whilst it remained decreased in three. No patient required dialysis. The percentage of diabetic patients were not found to be different in patients with and without signs of CMN. Conclusions.,The present retrospective study indicate that the risk of CMN in connection with angiography is low when modern low-osmolality CM and contrast saving angiographic technique including CO2 is used combined with proper hydration. Patients with diabetes mellitus were not found more frequently in the groups with CMN. [source] Why Have Child Maltreatment and Child Victimization Declined?JOURNAL OF SOCIAL ISSUES, Issue 4 2006David Finkelhor Various forms of child maltreatment and child victimization declined as much as 40,70% from 1993 until 2004, including sexual abuse, physical abuse, sexual assault, homicide, aggravated assault, robbery, and larceny. Other child welfare indicators also improved during the same period, including teen pregnancy, teen suicide, and children living in poverty. This article reviews a wide variety of possible explanations for these changes: demography, fertility and abortion legalization, economic prosperity, increased incarceration of offenders, increased agents of social intervention, changing social norms and practices, the dissipation of the social changes from the 1960s, and psychiatric pharmacology. Multiple factors probably contributed. In particular, economic prosperity, increasing agents of social intervention, and psychiatric pharmacology have advantages over some of the other explanations in accounting for the breadth and timing of the improvements. [source] The correlation of metallicity gradient with galaxy massMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2005Duncan A. Forbes ABSTRACT A number of previous studies have searched for a correlation between radial metallicity gradients and early-type galaxy mass , no convincing trends have been found. Here we re-examine this issue with several key enhancements: using total metallicity from studies that have broken the age,metallicity degeneracy, excluding galaxies with young stellar ages (i.e. those that have experienced a recent central starburst) and using the K band to derive galaxy luminosities. We find that Coma cluster galaxies have metallicity gradients that correlate with galaxy mass. Furthermore, gradients have values similar to those of monolithic collapse models. The combination of dissipative formation and energy injection from supernovae provides a mechanism for the trends with galaxy mass; however, other explanations are possible. Additional high-quality observational data are needed to constrain further the gas physics involved in galaxy formation. [source] Host specificity and geographic range in haematophagous ectoparasitesOIKOS, Issue 3 2005Boris R. Krasnov A negative interspecific correlation between the degree of habitat specialization and the size of a species' geographic range has been documented for several free living groups of organisms, providing support for the niche breadth hypothesis. In contrast, practically nothing is known about the geographic range sizes of parasitic organisms and their determinants. In the context of the niche breadth hypothesis, parasites represent ideal study systems, because of the well documented variation in host specificity among parasite species. Here, we investigated the relationship between host specificity (a measure of niche breadth) and geographic range size among flea species parasitic on small mammals, using data from seven distinct geographical regions. Two measures of host specificity were used: the number of host species used by a flea species, and a measure of the average taxonomic distance between the host species used by a flea; the latter index provides an evolutionary perspective on host specificity. After correcting for phylogenetic influences, and using either of our two measures of host specificity, the degree of host specificity of fleas was negatively correlated with the size of their geographic range in all seven regions studied here, with only one minor exception. Overall, these results provide strong support for the niche breadth hypothesis, although other explanations cannot be ruled out. [source] Polyploidy in vertebrate ancestry: Ohno and beyondBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2004REBECCA F. FURLONG Over 30 years ago, Susumu Ohno proposed that two rounds of polyploidy occurred early in vertebrate evolution. We re-examine this proposal using three recent lines of evidence. First, total gene number estimates from completely sequenced genomes suggest an increase in total gene number somewhere along the vertebrate or prevertebrate lineage, compatible with Ohno's model. Second, analyses of homeobox and other genes from amphioxus reveal very extensive gene duplication specifically on the vertebrate lineage. This refines the timing of putative polyploidy to after the divergence of amphioxus and vertebrates. Third, the existence of four-fold paralogy regions in the human genome is suggestive of two rounds of polyploidy, although other explanations are possible. We propose an experimental test, based on chromosomal localization of genes in amphioxus, that should resolve whether paralogy regions are indeed remnants of duplication in vertebrate ancestry. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82, 425,430. [source] | ||||||||||||||||