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1.
Deirdre Oakley 《Ethnic and racial studies》2013,36(9):1576-1598
One-third of public school students are racial and/or ethnic minorities. Yet only 14 per cent of teachers represent these groups. Frequently lost in broader debates concerning this disparity is the paradoxical contribution of the 1954 Brown v. Board of Education decision. Schools were mandated under Brown to desegregate the student body. But the law did not necessarily protect the jobs of black teachers and administrators. Using a unique database of court orders, we examine the impact of mandated desegregation on black teachers. Findings indicate regional differences. Mandated desegregation created conditions that resulted in decreases in the black teaching force in the South. The opposite occurred in the non-south, with mandated desegregation positively associated with increases (although small) in the black teaching force. Our findings suggest that the legacy of mandated desegregation may have created broader institutional conditions in which black and other minority teachers remain underrepresented in the teaching force. 相似文献
2.
The social impacts of the heat–health watch/warning system in Phoenix,Arizona: assessing the perceived risk and response of the public 总被引:2,自引:0,他引:2
Heat is the leading weather-related killer in the United States. Although previous research suggests that social influences
affect human responses to natural disaster warnings, no studies have examined the social impacts of heat or heat warnings
on a population. Here, 201 surveys were distributed in Metropolitan Phoenix to determine the social impacts of the heat warning
system, or more specifically, to gauge risk perception and warning response. Consistent with previous research, increased
risk perception of heat results in increased response to a warning. Different social factors such as sex, race, age, and income
all play an important role in determining whether or not people will respond to a warning. In particular, there is a strong
sense of perceived risk to the heat among Hispanics which translates to increased response when heat warnings are issued.
Based on these findings, suggestions are presented to help improve the Phoenix Heat Warning System. 相似文献
3.
Díaz J García-Herrera R Trigo RM Linares C Valente MA De Miguel JM Hernández E 《International journal of biometeorology》2006,50(3):159-166
We present a new approach to improve the reliability of quantifying the impact of a heat wave on mortality rates. We show,
for the recent European summer 2003 heat wave, that the use of absolute maximum temperature values, or number of days above
a given threshold, can be misleading. Here, we have assessed the impact of the heat wave on Iberian mortality by applying
a four step procedure: (1) calculating, for each observatory, the local maximum temperature (T
max) distributions, (2) calculating the corresponding 95th percentile values (T
threshold), (3) locally defining extremely hot days (EHD) as those days on which the local threshold of the 95th percentile of the
series is exceeded, and (4) calculating the total degrees-days (DD) of exceedance, by calculating the difference T
max−T
threshold and summing these values for all days above T
threshold. We show that the relationship between summer mortality rates and the DD index is non-linear and can be described by a logarithmic
function, with a correlation coefficient of 0.78, which explains 60.6% of the mortality variance (F value of 24.64, significant at P<0.0001). Using maximum temperatures, no significant relationship is found with mortality, whereas the EHD frequency shows
a significant association with mortality, albeit weaker than that obtained with DD. 相似文献
4.
José Luís Ochoa Arturo Sánchez-Paz Ariel Cruz-Villacorta Erick Nunez-Vázquez Arturo Sierra-Beltrán 《Hydrobiologia》1997,352(1-3):195-200
Previously considered as toxin-free, the Baja California Peninsula has witnessed several toxic algal blooms during the past
three years. Apparently these ‘red-tide’ phenomena's outbreaks are not linked to any human related activity. This may just
reflect better detection and training. Such events may be periodical and natural rather than induced. The most common types
of marine toxins have been detected along the coast of the Peninsula and neighboring waters by mouse bioassay and chromatographic
techniques. These are: Tetrodotoxin (TTX), Amnesic Shellfish Poison (ASP), Paralytic Shellfish Poisons (PSP), Diarrhetic Shellfish
Poisons (DSP) and even Ciguatera (CFP), which are related to the presence of organisms of Prorocentrum sp. and Alexandrium
sp. groups, and the diatom Pseudonitzschia sp. among others. There are also some indications about different kinds of TTX
in the puffer fish of the region, and reasons to believe that we are facing a quite different pattern in toxic components,
since PSP toxic potency (defined as the number of mouse units per gram(MU/g)of shellfish meat) is very high in spite of low
dinoflagellates cell density registered. The ecological and social impact of the above has been considerable, with mass deaths
of shellfish, seagulls, dolphins and turtles, and even some human casualties. The locally registered toxicity records: PSP
found in one single fanshell reaches to 23 000 MU/100 g of tissue as determined by the mouse bioassay and, on a different
event, two persons killed after ingesting puffer fish fillet. The largest reservoir of commercial marine organisms in Mexico
is precisely the Northwest coast of the country and important plans for building large harbors and develop aquaculture areas
are in progress. Therefore, a monitoring program is essential for an adequate management of such resources. Considering the
large extension of the Peninsula (about1600 km)and, at this time, the lack of efficient communication means and scarce population,
the implementation of such monitoring programs presents a big challenge.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
6.
The temperature–mortality relationship follows a well-known J-V shaped pattern with mortality excesses recorded at cold and hot temperatures, and minimum at some optimal value, referred as Minimum Mortality Temperature (MMT). As the MMT, which is used to measure the population heat-tolerance, is higher for people living in warmer places, it has been argued that populations will adapt to temperature changes. We tested this notion by taking advantage of a huge migratory flow that occurred in Italy during the 1950s, when a large number of unemployed people moved from the southern to the industrializing north-western regions. We have analyzed mortality–temperature relationships in Milan residents, split by groups identified by area of birth. In order to obtain estimates of the temperature-related risks, log-linear models have been used to fit daily death count data as a function of different explanatory variables. Results suggest that mortality risks differ by birthplace, regardless of the place of residence, namely heat tolerance in adult life could be modulated by outdoor temperature experienced early in life. This indicates that no complete adaptation might occur with rising external environmental temperatures. 相似文献
7.
Zhiwei Xu Perry E. Sheffield Hong Su Xiaoyu Wang Yan Bi Shilu Tong 《International journal of biometeorology》2014,58(2):239-247
Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children’s health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: “heatwave”, “heat wave”, “child health”, “morbidity”, “hospital admission”, “emergency department visit”, “family practice”, “primary health care”, “death” and “mortality”. Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children’s health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children’s health perspective, identifying the best measure of children’s exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children’s birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children’s disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended. 相似文献
8.
Erin D'Agnese Dyanna Lambourn James Rice Debbie Duffield Jessica Huggins Terry Spraker Stephen Raverty Tetiana Kuzmina Michael E. Grigg Kristin Wilkinson Steven Jeffries Woutrina Smith 《Marine Mammal Science》2020,36(3):828-845
Guadalupe fur seals (GFS), Arctocephalus philippii townsendi, an U.S. Endangered Species Act threatened pinniped, have recently reappeared in their historic range along the western seaboard of the continental United States. Starting 2005 through 2016, 169 GFSs stranded in Washington and Oregon, involving two designated unusual mortality events. The circumstances surrounding GFS strandings, mortality, and their increased presence in Oregon and Washington were analyzed during this study. Detailed necropsies, histopathology (n = 93), and epidemiological analysis found three main causes of death (COD): emaciation (44%), trauma (29%), and infectious disease (19%) and the factors associated with overall strandings and emaciation. Trauma included many cases found associated with fisheries interactions and clustered near the mouth of the Columbia River, where high levels of commercial fishing occur. The most common pathogens found associated with disease were Toxoplasma gondii, Sarcocystis neurona, and gastrointestinal helminths. Seasonality and upwelling were associated with higher stranding numbers regardless of COD. Seasonal migration into the region, coinciding with postweaning, suggests young GFSs are in search of prey and habitat resources. Reemergence of GFSs is likely due to conservation efforts, which have been critical for species recovery in the region. Continued monitoring is needed as this vulnerable species continues to rebound. 相似文献
9.
Kevin A. Raskoff 《Hydrobiologia》2001,451(1-3):121-129
For over 10 years, the midwater ecology group at MBARI has compiled video and accompanying physical data with the ROV Ventana operating in mesopelagic depths of Monterey Bay, CA in order to elucidate patterns in midwater ecology. Two El Niño events have occurred during this time period, in 1991–92 and in 1997–98. The oceanographic metric of spiciness combines temperature and salinity data into one sensitive measurement. Although temperature and salinity measurements alone revealed no clear patterns, clear signals of spiciness were observed that corresponded to water mass intrusions into the deep waters of the bay during the two El Niño events. During these events, some seldom-seen species were observed in high numbers in the midwater, while historically common species became rare. During non-El Niño years, the leptomedusa Mitrocoma cellularia(A. Agassiz, 1865) was common in the surface waters (0–50 m) of Monterey Bay, but it was not abundant at depth, while the trachymedusa Colobonema sericeum Vanhöffen, 1902 was found in relatively high numbers at mesopelagic depths. During the last two El Niño events, M. cellulariawas observed in higher numbers at mesopelagic depths, whereas C. sericeum was scarce. M. cellularia was found in a wider range of temperatures, salinities, and dissolved oxygen values than was C. sericeum. Transport and tolerance hypotheses are proposed to explain differences in the presence and numerical density of the medusae. 相似文献
10.
Ann E. Wiringa Kathleen A. Shutt Jane W. Marsh Amanda C. Cohn Nancy E. Messonnier Shelley M. Zansky Susan Petit Monica M. Farley Ken Gershman Ruth Lynfield Arthur Reingold William Schaffner Jamie Thompson Shawn T. Brown Bruce Y. Lee Lee H. Harrison 《PloS one》2013,8(12)
Background
The detection of meningococcal outbreaks relies on serogrouping and epidemiologic definitions. Advances in molecular epidemiology have improved the ability to distinguish unique Neisseria meningitidis strains, enabling the classification of isolates into clones. Around 98% of meningococcal cases in the United States are believed to be sporadic.Methods
Meningococcal isolates from 9 Active Bacterial Core surveillance sites throughout the United States from 2000 through 2005 were classified according to serogroup, multilocus sequence typing, and outer membrane protein (porA, porB, and fetA) genotyping. Clones were defined as isolates that were indistinguishable according to this characterization. Case data were aggregated to the census tract level and all non-singleton clones were assessed for non-random spatial and temporal clustering using retrospective space-time analyses with a discrete Poisson probability model.Results
Among 1,062 geocoded cases with available isolates, 438 unique clones were identified, 78 of which had ≥2 isolates. 702 cases were attributable to non-singleton clones, accounting for 66.0% of all geocoded cases. 32 statistically significant clusters comprised of 107 cases (10.1% of all geocoded cases) were identified. Clusters had the following attributes: included 2 to 11 cases; 1 day to 33 months duration; radius of 0 to 61.7 km; and attack rate of 0.7 to 57.8 cases per 100,000 population. Serogroups represented among the clusters were: B (n = 12 clusters, 45 cases), C (n = 11 clusters, 27 cases), and Y (n = 9 clusters, 35 cases); 20 clusters (62.5%) were caused by serogroups represented in meningococcal vaccines that are commercially available in the United States.Conclusions
Around 10% of meningococcal disease cases in the U.S. could be assigned to a geotemporal cluster. Molecular characterization of isolates, combined with geotemporal analysis, is a useful tool for understanding the spread of virulent meningococcal clones and patterns of transmission in populations. 相似文献11.
Sandström ME Siegler JC Lovell RJ Madden LA McNaughton L 《Cell stress & chaperones》2008,13(2):169-175
The purpose of this study was to investigate the alterations in serum heat shock protein (Hsp) 70 levels during a 15-consecutive-day
intermittent heat–exercise protocol in a 29-year-old male ultra marathon runner. Heat acclimation, for the purpose of physical
activities in elevated ambient temperatures, has numerous physiological benefits including mechanisms such as improved cardiac
output, increased plasma volume and a decreased core temperature (T
c). In addition to the central adaptations, the role of Hsp during heat acclimation has received an increasing amount of attention.
The acclimation protocol applied was designed to correspond with the athlete’s tapering period for the 2007 Marathon Des Sables.
The subject (VO2max = 50.7 ml·kg−1·min−1, peak power output [PPO] = 376 W) cycled daily for 90 min at a workload corresponding to 50% of VO2max in a temperature-controlled room (average WBGT = 31.9 ± 0.9°C). Venous blood was sampled before and after each session
for measurement of serum osmolality and serum Hsp70. In addition, T
c, heart rate (HR) and power output (PO) was measured throughout the 90 min to ensure that heat acclimation was achieved during
the 15-day period. The results show that the subject was successfully heat acclimated as seen by the lowered HR at rest and
during exercise, decreased resting and exercising T
c and an increased PO. The heat exercise resulted in an initial increase in Hsp70 concentrations, known as thermotolerance,
and the increase in Hsp70 after exercise was inversely correlated to the resting values of Hsp70 (Spearman’s rank correlation = −0.81,
p < 0.01). Furthermore, the 15-day heat–exercise protocol also increased the basal levels of Hsp70, a response different from
that of thermotolerance. This is, as far as we are aware, the first report showing Hsp70 levels during consecutive days of
intermittent heat exposure giving rise to heat acclimation. In conclusion, a relatively longer heat acclimation protocol is
suggested to obtain maximum benefit of heat acclimation inclusive of both cellular and systemic adaptations. 相似文献
12.
《Journal of biological education》2012,46(4):350-364
AbstractTeachers need to be aware of biology misconceptions in their classrooms and how to address them. In response, researchers and science educators have suggested and examined effective practices to prevent and ameliorate misconceptions. An extensive review of the literature gives researchers and educators insights into trends, practices, and gaps in the misconceptions research and helps decide which issues to address and why. The current study shares how researchers in Turkey conduct a content analysis of published misconception research in Turkey by using a form. The analysis resulted in a meta-synthesis (thematic content analysis) that inventoried and compared the purposes, research methods, data collection instruments, and findings of the selected publications. Biology educators in other regions of the world can inform their practice by using this instrument and research methods to learn about trends and patterns in misconception research. Researchers will gain insights into effective methods that have been used to examine misconceptions and will be able to identify biology misconceptions that have been under-investigated and need further analysis. 相似文献
13.
Helena Popławska Adam Wilczewski Agnieszka Dmitruk Wojciech Hołub 《Economics & Human Biology》2013,11(2):221-226
The aim of this study was to determine secular changes in the sexual maturation of children and adolescents from Eastern regions of Poland between 1980 and 2000, with special attention paid to rural–urban differences. Our sample comprised 34,055 girls and 28,100 boys from 9 to 18 years of age. The age at which each gender reached each stage of sexual maturation was examined, along with menarcheal age in girls. An increase in the rate of sexual maturation was observed over the 20-year period of this study. Menarcheal age in girls decreased by 0.59 years. The length of sexual maturation decreased: from 6.58 years to 3.85 years in girls and from 5.84 years to 3.65 years in boys. A significantly faster rate of sexual maturation was observed between 1990 and 2000. Over the entire 20-year period, adolescents living in rural settings experienced a slower rate of sexual maturation than did their urban peers. 相似文献
14.
In this work, we correlate the daily number of human leptospirosis cases with several climatic factors. We used a negative
binomial model that considers hospital daily admissions due to leptospirosis as the dependent variable, and the climatic variables
of daily precipitation pattern, and maximum and minimum temperature as independent variables. We calculated the monthly leptospirosis
admission probabilities from the precipitation and maximum temperature variables. The month of February showed the highest
probability, although values were also high during the spring months. The month of February also showed the highest number
of hospital admissions. Another interesting result is that, for every 20 mm precipitation, there was an average increase of
31.5% in hospital admissions. Additionally, the relative risk of leptospirosis varied from 1.1 to 2.0 when the precipitation
varied from 20 to 140 mm. 相似文献
15.
Postma E 《PloS one》2007,2(10):e999
Amongst the numerous problems associated with the use of impact factors as a measure of quality are the systematic differences in impact factors that exist among scientific fields. While in theory this can be circumvented by limiting comparisons to journals within the same field, for a diverse and multidisciplinary field like evolutionary biology, in which the majority of papers are published in journals that publish both evolutionary and non-evolutionary papers, this is impossible. However, a journal's overall impact factor may well be a poor predictor for the impact of its evolutionary papers. The extremely high impact factors of some multidisciplinary journals, for example, are by many believed to be driven mostly by publications from other fields. Despite plenty of speculation, however, we know as yet very little about the true impact of evolutionary papers in journals not specifically classified as evolutionary. Here I present, for a wide range of journals, an analysis of the number of evolutionary papers they publish and their average impact. I show that there are large differences in impact among evolutionary and non-evolutionary papers within journals; while the impact of evolutionary papers published in multidisciplinary journals is substantially overestimated by their overall impact factor, the impact of evolutionary papers in many of the more specialized, non-evolutionary journals is significantly underestimated. This suggests that, for evolutionary biologists, publishing in high-impact multidisciplinary journals should not receive as much weight as it does now, while evolutionary papers in more narrowly defined journals are currently undervalued. Importantly, however, their ranking remains largely unaffected. While journal impact factors may thus indeed provide a meaningful qualitative measure of impact, a fair quantitative comparison requires a more sophisticated journal classification system, together with multiple field-specific impact statistics per journal. 相似文献
16.
Markus Lange Wolfgang W. Weisser Martin M. Gossner Esther Kowalski Manfred Türke Fernando Joner Carlos Roberto Fonseca 《Biodiversity and Conservation》2011,20(10):2133-2147
Land use intensification in forests is a main driver of global biodiversity loss. Although historical state of land use differs
between subtropical and temperate zones, gradients of land-use intensities similarly range from unmanaged to very intensively
managed forests. Irrespective of similar land use forces in both climate zones, comparative studies on land use effects are
still rare. Such studies are, however, promising in discovering more general impacts and geographical specifics of land use
intensification. We studied litter-dwelling invertebrates along a gradient of increasing land use intensity in subtropical
forests in Southern Brazil and temperate forests in Central Europe using similar sampling designs. Effects of land use intensity
on the entire community were analyzed on the level of orders and feeding guilds. In both climate zones a similar number of
individuals were caught when standardizes to 100 pitfall trap days, but taxa richness was higher in the subtropics. Moreover,
community composition differed between both climate zones. In both regions, land use intensity did not affect taxa richness,
but invertebrate abundance was affected in opposite ways; while increasing land use intensity resulted in a decrease of invertebrate
abundance in the subtropics, an increase was observed in the temperate zone and this was mostly consistent regarding different
feeding guilds. Management practices should take into account that the effect of land use intensity on biodiversity can differ
drastically among climatic regions. 相似文献
17.
Mostafa A. Yehia Tarek S. El-Ammawi Khairia M. Al-Mazidi Mahmoud A. Abu El-Ela Hejab S. Al-Ajmi 《Mycopathologia》2010,169(4):241-246
Background
Fungal infections constitute a major health problem all over the world. Signs and symptoms induced by various dermatophytic infections are difficult to distinguish clinically from each other. So, characterization by in vitro culture is required for appropriate diagnosis and treatment as well as to study the epidemiological characteristics in a region. 相似文献18.
Olivier Telle Alain Vaguet N. K. Yadav B. Lefebvre Eric Daudé Richard E. Paul A. Cebeillac B. N. Nagpal 《PloS one》2016,11(1)
Background
Dengue is a major international public health concern, one of the most important arthropod-borne diseases. More than 3.5 billion people are at risk of dengue infection and there are an estimated 390 million dengue infections annually. This prolific increase has been connected to societal changes such as population growth and increasing urbanization generating intense agglomeration leading to proliferation of synanthropic mosquito species. Quantifying the spatio-temporal epidemiology of dengue in large cities within the context of a Geographic Information System is a first step in the identification of socio-economic risk factors.Methodology/Principal Findings
This Project has been approved by the ethical committee of Institut Pasteur. Data has been anonymized and de-identified prior to geolocalisation and analysis. A GIS was developed for Delhi, enabling typological characterization of the urban environment. Dengue cases identified in the Delhi surveillance system from 2008 to 2010 were collated, localised and embedded within this GIS. The spatio-temporal distribution of dengue cases and extent of clustering were analyzed. Increasing distance from the forest in Delhi reduced the risk of occurrence of a dengue case. Proximity to a hospital did not increase risk of a notified dengue case. Overall, there was high heterogeneity in incidence rate within areas with the same socio-economical profiles and substantial inter-annual variability. Dengue affected the poorest areas with high density of humans, but rich areas were also found to be infected, potentially because of their central location with respect to the daily mobility network of Delhi. Dengue cases were highly clustered in space and there was a strong relationship between the time of introduction of the virus and subsequent cluster size. At a larger scale, earlier introduction predicted the total number of cases.Conclusions/Significance
DENV epidemiology within Delhi has a forest fire signature. The stochastic nature of this invasion process likely smothers any detectable socio-economic risk factors. However, the significant finding that the size of the dengue case cluster depends on the timing of its emergence emphasizes the need for early case detection and implementation of effective mosquito control. A better understanding of the role of population mobility in contributing to dengue risk could also help focus control on areas at particular risk of dengue virus importation. 相似文献19.
The summer flounder, or fluke (Paralichthys dentatus)supports the most important commercial and recreational flatfishfisheries of the U.S. Atlantic coast. Thestock and fishery range from Massachusetts toNorth Carolina. Spawning takes place during aprotracted season that can extend fromSeptember to March, during an annual offshoreand southern migration to the outer continentalshelf off Virginia and North Carolina. Thefish are con-centrated in bays and estuariesfrom late spring through early autumn, when thenext offshore migration begins. The assessmentand management of the summer flounder fisheryhas been very contentious since theimplementation of the joint Atlantic StatesMarine Fisheries Commission/Mid-AtlanticFishery Management Council Fishery ManagementPlan (FMP) in 1989, when the poor status of thesummer flounder stock was evident toscientists, managers, and fishermen. Amendment2 to the FMP, approved in 1992, implementedseveral major regulatory provisions includingannual commercial quotas and recreationalharvest limits, and annually adjustable minimumlanded fish sizes, minimum mesh sizes,possession limits, and seasonal closures. By1999, fishing mortality on summer flounder haddeclined to its lowest level since the 1960s,and summer flounder total stock biomass was thehighest since the mid-1970s. Monitoring ofstock status is ongoing to reliably determine``how much fish is enough' to provide forlong-term sustainability. Many changes are madeannually to management measures due todiffering interpretations of stock status bymanagers, and fishery and environmentaladvocacy groups. Attainment of the annualfishing mortality targets remains elusive. Themultiple layers of science, management, andpolitics in place since 1992 continue to sparkmuch controversy and litigation that increasingly places the management of the summer flounder fishery in the hands of the courts. 相似文献