Colony Population Research Articles

Kajian Fungi Mikoriza Arbuskula dan Populasi Bakteri pada Mikorhizosfer Semai Mahoni (Swietenia macrophylla King.) dalam Pot Organik

The mycorrhizosphere is the zone of soil influenced by roots colonized by mycorrhizal fungi and contains many microorganisms. This study aims to analyze mycorrhizal and bacterial populations in the mycorrhizosphere of ​​mahogany (Swietenia macrophylla King.) seedlings growing in silica sand post-mining media by using organic pot as container growth media. The experimental design used was a Completely Randomized Design (CRD) consisting of two treatments, namely the composition and size of organic pot materials. The results showed that the composition of the organic pot could affect the presence of AMF spores. The organic pots composition of 50% newspaper, 35% compost, and 15% cocopeat showed the best results for the development of AMF spores and bacterial colonies, the development of AMF spores and bacterial colony populations in growing media was better than the development of AMF spores and bacterial colonies in organic pots. There are seven different morphological characters of bacterial colonies which are dominated by round, thready, flat, and white.
 Keywords: arbuscular mycorrhizal fungi (AMF), bacteria, correlation, mahagony, mycorrhizosphere

Citizens, Subjects, Enemies: The First World War and Citizenship Policies in the Italian Colonies

There are few research fields in European history that have received as much scholarly attention over the last few years as citizenship and the First World War. While this is also true for the Italian case, there is still a striking absence of research on citizenship laws in the colonial territories under Italian sovereignty. The present article addresses this gap and challenges the long-established assumption – due to an all too narrow focus on the historical military framework – that the First World War did not really affect the colonies of the Kingdom of Italy. An investigation of how the legal status of the colonial population – especially in Eritrea, on the one hand, and in Tripolitania and Cyrenaica, on the other – was regulated, but also contested, claimed and negotiated, both during the conflict and in its immediate aftermath, reveals that a global event like the First World War actually had a significant impact on the Italian territories in the Horn of Africa and in North Africa. To illustrate this point, the article adopts an approach based on local players in the colonies rather than on legislators or policymakers in the metropole. Contemporary sources collected from several different archives are used to retrace personal stories and administrative processes which reveal important aspects in the story not only of Italian colonialism but of the Italian state in general. Citizenship in the Italian territories in Africa, as much as in other European colonies, was marked by the prejudicial concept of the backwardness of Africans, who were thus excluded from metropolitan citizenship. Beyond that, the article highlights utilitarianism as a concept that can help us to understand how Italy dealt with the inhabitants of its colonies during the First World War.

Defensive Behaviors of the Central Highland Honeybees, Apis mellifera bandasii against Varroa destructor in Ethiopia

The parasitic mite V. destructor has caused long-lasting losses to the survival of European honeybee colonies. In contrast, African honeybees are likely capable of surviving the effects of this parasitic mite with varying defense mechanisms. This study provides insights into two defense behavioral traits, including hygienic and grooming behaviors of local honeybee, Apis mellifera bandasii colonies against V. destructor mite in Ethiopia. Hygienic behavior (HB) was evaluated using the standard pin-killed brood method by calculating the dead brood removal rates (%) at 24 and 48 hrs. While grooming behavior (GB) was assessed by measuring the number of daily fallen mites and the percentage of damaged mites. The results of hygienic behavior showed greater brood removal rates of 83.1±14.3% and 97.6±3.4% at 24 hrs and 48 hrs, respectively. There were strong negative correlations between the HB and Varroa infestation rates, indicating that HB has the potential to reduce the mite population in colonies. Grooming behavior also showed higher mean daily fallen mites per colony (16.3±10.2), of which about 80% of the total fallen mites (n=488) were damaged. Ten body damage categories were identified, with most damages inflicted on mites’ legs, dorsal shield, and gnathosoma because of the GB. Our study suggests that combined hygienic and grooming behaviors could be used as effective defenses against V. destructor infestations in A. m. bandasii colonies. Therefore, future selective breeding programs should integrate these specific host defenses in order to produce sustainable colonies resistant to this parasitic mite.

Effect of dietary supplement on the reproductive traits, products and behavioral characteristics of the European honey bee (Apis mellifera)

We evaluated the effects of dietary supplements on hive populations of the European honey bee (Apis mellifera) through experimental trials. The population, reproduction rate, quality of honey, quantity and quality of venom, and behavioral characteristics of 15 hives were assessed in a randomized experimental design with three groups and five replicates. Each replicate contained one modern Langstroth–Hive. The experimental period was 86 days, and each hive in the control group (control), received 500 mL syrup without dietary supplement per day (sugar and water in equal quantities), Group 1 received 500 mL syrup with 5 g dietary supplement added, and Group 2 received 500 mL syrup with 10 g dietary supplement added. The colony population and reproduction rate increased significantly in both treatment groups (p < 0.01). Honey production increased significantly in Group 2 (p < 0.05). Diastase activity and protein and sucrose content in honey increased significantly in both groups (p < 0.05). The general behavior of the bees improved significantly in both groups (p < 0.01). Aggressive behavior decreased significantly in Group 2 (p < 0.01). Overall, Group 2 showed statistically significant improvements which were better than Group 1.

Investigating temporal bone variation of colonial populations from St-Lawrence Valley, Quebec: A 3D geometric morphometric approach.

In Quebec, genetic and genealogical research are used to document migratory events and family structures since colonial times, because bioarchaeological analysis is limited by poor skeletal preservation. This article aims to fill this gap by exploring past population structure in the St-Lawrence Valley from the French (1683-1760) and British (1760-1867) regimes using morphological variation of well-preserved temporal bones. 3D geometric morphometrics shape data from seven populations (five Catholics of French descent and two Protestants of British descent; n = 214) were collected from temporal bones. Using Procrustes distances and both MANOVA and Discriminant Function Analysis, morphological differences were measured to calculate affinities patterns among populations. Shape variations were explored with between-group analysis, Mahalanobis distances and quantified by means of Fst estimates using Relethford-Blangero analysis. Despite strong affinities between all Catholic cemeteries, all show divergent morphological regional diversity -especially Montreal and the fortified villages dedicated to its defense. Montreal exhibits low increase in morphological variance over three centuries. As our results show no morphological differences between the Catholic and the Protestant cemeteries in Montreal, this fact may highlight the potential presence of Irish or admixed individuals in Montreal cemeteries after the British takeover. Patterns of morphological diversity highlighted that French colonists did not equally contribute to the descendant populations as reflected by significant interregional variation. Although historical records show that French and English-speaking populations did not tend to admix, morphological affinities between Protestants and Catholics in the beginning of the industrial era in Montreal could reflect the genetic contribution of Catholic Irish migrants. All Catholic cemeteries display distinct morphologies, highlighting differential contributions from French colonists and founder effects, which have increased regional differences. Montreal Catholic (French descent) and Protestant (English colonists) cemeteries show significant morphological affinities at the beginning of the industrial era. The Irish migration following the British conquest may explain morphological similarities observed between Catholic and Protestant cemeteries.

Free-living colonies of native honey bees (Apis mellifera mellifera) in 19th and early 20th century Sweden

Little information exists on the history and ecology of free-living colonies of European honey bees (Apis mellifera L.) in Europe, including its dark north-western subspecies (Apis mellifera mellifera). Our aim was to investigate the presence of colonies of free-living, native honey bees (A. m. mellifera) during the last two centuries in Sweden. For this we examined systematic interviews of beekeepers (176 answers from 158 questionnaires) performed in the years 1928–1981, with information dating back to the early 1800s. An overwhelming majority of answers (96%) confirmed the past presence of free-living colonies of honey bees in Sweden. While some stated that free-living colonies were simply absconded swarms from managed hives, the majority of interviewees (69%) believed that free-living colonies were of a truly wild origin. A decreasing trend in first-hand accounts of free-living colonies suggests that free-living populations underwent a dramatic decline at the end of the 19th century. This was also expressed in words by many interviewees, who in 14 cases stated that the loss of old forests and tree-cavity nest sites at the end of the 1800s was the primary cause of the decline. Direct accounts of perennial, free-living colonies, combined with detailed descriptions of the collection of large free-living colonies and/or wild honey, is strong evidence of free-living honey bees being well adapted to winter survival. These accounts contradict the officially supported view that the honey bee is a recently imported, domesticated, non-native species in Sweden. The results give a scientific underpinning and provide inspiration for the restoration of native forests which could facilitate populations of free-living colonies of A. m. mellifera exposed to natural selection. This could potentially lead to its return as a fully wild species. In an uncertain future, allowing for a natural lifestyle could increase resilience and reinstate characteristics that are otherwise lost in honey bees due to the increasing effects of artificial trait selection.Implications for insect conservationOur results present strong evidence for populations of free-living colonies of A. m. mellifera in the recent past, which calls for a revised look at its conservation status and management. Allowing and supporting free-living colonies of this subspecies should be evaluated as a method for conservation.

From “Chinese Colonist” to “Yellow Peril”: Capitalist Racialization in the British Empire

The literature on “racial capitalism” exhibits a tension between the term’s evocative power and its conceptual imprecision. This article navigates this tension by developing the mid-level concept of “capitalist racialization,” which specifies the role of capitalist abstractions in the construction of racial hierarchies. I elaborate this notion around the racialization of Chinese migration in nineteenth-century Southeast Asia. I focalize the figure of the “Chinese colonist” as an index of the capitalist standards by which British observers ordered colonial populations in their reflections on imperial political economy. I argue that the racial stereotype of “the Chinese” as commercial, industrious, and “colonizing” people emerged from the subsumption of colonial land and labor under capital. Their “colonizing” capacity rendered Chinese migrants simultaneously an economic asset to the British Empire and a potential threat to the white world order. “Capitalist racialization” therefore highlights new inroads into the entwined histories of capitalism, racism, and empire.

Clean water supply and urban hygiene control in colonial Semarang, Indonesia

ABSTRACT This article discusses the endeavors of the municipality council of Semarang to establish a water governance system to tackle the crisis of safe water in the early twentieth century. The establishment of a water management system was deemed crucial owing to Semarang's transformation into an urban area with a heightened susceptibility to cholera outbreaks. The situation was further exacerbated by the increasing encroachment of the colonial population into Semarang from the late nineteenth century, coinciding with the surge in industrialization. Subsequently, a decentralized government of Semarang sought to address this issue since 1906, through the implementation of innovative technologies to produce safe water sources for public consumption and improving the water distribution system. Unfortunately, the series of programs proved insufficient in comprehensively addressing the socio-economic hurdles faced by the local community, as demonstrated by the continued exclusion of Semarang's disadvantaged population from adequate clean water access.

Carbohydrate nutrition associated with health of overwintering honey bees.

In temperate climates, honey bees rely on stored carbohydrates to sustain them throughout the winter. In nature, honey serves as the bees' source of carbohydrates, but when managed, beekeepers often harvest honey and replace it with cheaper, artificial feed. The effects of alternative carbohydrate sources on colony survival, strength, and individual bee metabolic health are poorly understood. We assessed the impacts of carbohydrate diets (honey, sucrose syrup, high-fructose corn syrup, and invert syrup) on colony winter survival, population size, and worker bee nutritional state (i.e., fat content and gene expression of overwintered bees and emerging callow bees). We observed a nonsignificant trend for greater survival and larger adult population size among colonies overwintered on honey compared to the artificial feeds, with colonies fed high-fructose corn syrup performing particularly poorly. These trends were mirrored in individual bee physiology, with bees from colonies fed honey having significantly larger fat bodies than those from colonies fed high-fructose corn syrup. For bees fed honey or sucrose, we also observed gene expression profiles consistent with a higher nutritional state, associated with physiologically younger individuals. That is, there was significantly higher expression of vitellogenin and insulin-like peptide 2 and lower expression of insulin-like peptide 1 and juvenile hormone acid methyltransferase in the brains of bees that consumed honey or sucrose syrup relative to those that consumed invert syrup or high-fructose corn syrup. These findings further our understanding of the physiological implications of carbohydrate nutrition in honey bees and have applied implications for colony management.

Effects of Genetic Origin of Honeybees and Climate on Prevalence and Infestation Levels of Varroa.

The objective of this study was to evaluate the effect of honeybee genetic origin, climate type and the interactions between these variables on the prevalence and infestation levels of Varroa in a large population of honeybee colonies (n = 1134). For each colony, the morphotype, haplotype and climate type were determined. No differences between the Africanized, European and Hybrid morphotypes were found for the prevalence and infestation levels of Varroa (p > 0.05). Differences between honeybee haplotypes were found for the prevalence of Varroa (p < 0.05), and the prevalence was higher in the African haplotype than in the European haplotype. No differences between honeybee haplotypes were found for the infestation levels of Varroa (p > 0.05). Differences were found between climate type for the prevalence and infestation levels of Varroa (p < 0.05): the temperate sub-humid climate had a higher prevalence and higher infestation levels than the semi-warm climate and the warm sub-humid climate. Correlations between the infestation levels of Varroa and mean annual temperature, mean annual precipitation, winter precipitation and Lang index were found.

Production and composition of extracellular polymeric substances by a unicellular strain and natural colonies of Microcystis: Impact of salinity and nutrient stress.

The transfer of toxic cyanobacterial Microcystis blooms from freshwater to estuaries constitutes a serious environmental problem worldwide that is expected to expand in scale and intensity with anthropogenic and climate change. The formation and maintenance of Microcystis in colonial form is conditioned to the presence of extracellular polymeric substances (EPS). In this study, we attempted to better understand how the mucilaginous colonial form of Microcystis evolves under environmental stress conditions. In particular, we studied and compared the production and the composition of EPS fractions (attached and free) from natural colonies of a Microcystis bloom and from a unicellular M. aeruginosa strain under salinity and nutrient stress (representing a land-sea continuum). Our results highlighted a greater production of EPS from the natural colonies of Microcystis than the unicellular one under nutrient and combined stress conditions dominated by the attached form. In comparison to the unicellular Microcystis, EPS produced by the colonial form were characterized by high molecular weight polysaccharides which were enriched in uronic acids and hexosamines, notably for the free fraction in response to increased salinities. This complex extracellular matrix gives the cells the ability to aggregate and allows the colonial cyanobacterial population to cope with osmotic shock.

A discrete, stochastic model of colonial phytoplankton population size structure: Development and application to in situ imaging-in-flow cytometer observations of Dinobryon.

The scientific community lacks models for the dynamic changes in population size structure that occur in colonial phytoplankton. This is surprising, as size is a key trait affecting many aspects of phytoplankton ecology, and colonial forms are very common. We aim to fill this gap with a new discrete, stochastic model of dynamic changes in phytoplankton colonies' population size structure. We use the colonial phytoplankton Dinobryon as a proof-of-concept organism. The model includes four stochastic functions-division, stomatocyst production, colony breakage, and colony loss-to determine Dinobryon population size structure and populations counts. Although the functions presented here are tailored to Dinobryon, the model is readily adaptable to represent other colonial taxa. We demonstrate how fitting our model to in situ observations of colony population size structure can provide a powerful approach to explore colony size dynamics. Here, we have (1) collected high-frequency in situ observations of Dinobryon in Lac (Lake) Montjoie (Quebec, Canada) in 2013 with a moored Imaging FlowCytobot (IFCB) and (2) fit the model to those observations with a genetic algorithm solver that extracts parameter estimates for each of the four stochastic functions. As an example of the power of this model-data integration, we also highlight ecological insights into Dinobryon colony size and stomatocyst production. The Dinobryon population was enriched in larger, flagellate-rich colonies near bloom initiation and shifted to smaller and emptier colonies toward bloom decline.

Impacts of fallow cropland winter “weeds” on honey bee pre-swarm colony growth

Lack of adequate floral resources is a key driver of bee population declines and honey bee colony loss, particularly in agricultural landscapes. Most studies evaluating floral resource use and land management consequences in honey bees focus on the period after new colony founding from reproductive swarms (spring-fall). Few studies have investigated nutrition in the late-winter/early-spring (LWES) period, the critical time when colonies break their winter dormancy and increase their colony populations in preparation for swarming. Growth during this timeframe influences beekeepers’ ability to produce new colonies and predicts colony productivity for the remainder of the active season. In agricultural areas growing summer annual crops, many fields are fallow during LWES and anecdotally grow large quantities of early blooming winter annual herbaceous “weeds”. The value of these resources to honey bee colony health is unknown. In this study, conducted in central Kentucky, we characterized blooming winter annual plant abundance across different land cover types. We placed colonies on sites with varying quantities of blooming winter annual plants and assessed colony growth and individual worker immune system function over LWES. We found that blooming winter annual plants are most abundant on croplands and limited on forested sites and sites dominated by grasses (including lawns and pastures). Colonies on sites with the lowest quantities of blooming winter annual plants showed reduced LWES growth and patterns of individual worker gene expression consistent with nutritional stress relative to colonies on sites with greater abundances of blooming winter annuals. We used the National Land Cover Database to show that proximity to crop fields at larger spatial scales also had positive impacts on colony growth during LWES. Taken together, these results suggest blooming winter annual plants, and, more generally, croplands, may provide critical floral resources for honey bees during the critical pre-swarm growth period following winter dormancy.

COVID-19 Booster Dose Coverage and Hesitancy among Older Adults in an Urban Slum and Resettlement Colony in Delhi, India.

The high prevalence of vaccine booster hesitancy, with the concomitant waning of humoral vaccine or hybrid immunity, and the emergence of SARS-CoV-2 variants of concern can accentuate COVID-19 morbidity and mortality. The study objective was to ascertain the COVID-19 vaccination coverage, including the administration of precaution (booster) dose vaccination, among the older population in an urban slum and resettlement colony population in Delhi, India. We conducted a cross-sectional survey in an urban resettlement colony, slum, and village cluster in the Northeast district of Delhi among residents aged ≥50 years. A total of 2217 adults (58.28%) had obtained a COVID-19 booster (precaution) dose vaccine, 1404 (36.91%) had received two doses of a COVID-19 vaccine without booster dose, 121 (3.18%) were unvaccinated, while 62 (1.63%) participants received a single dose. Based on adjusted analysis, older adults (>65 years), higher education, and higher per-capita income were statistically significant predictors of booster dose vaccination. More than four in ten adults in an urban slum and resettlement colony in Delhi lacked COVID-19 booster dose vaccination despite high rates of double-dose vaccination (~95%). Public health programming should provide an enhanced focus on reducing complacency with renewed prioritization for improving ease of access to COVID-19 vaccination services, particularly in underserved areas.

A selected organosilicone spray adjuvant does not enhance lethal effects of a pyrethroid and carbamate insecticide on honey bees.

As part of the agricultural landscape, non-target organisms, such as bees, may be exposed to a cocktail of agrochemicals including insecticides and spray adjuvants like organosilicone surfactants (OSS). While the risks of insecticides are evaluated extensively in their approval process, in most parts of the world however, authorization of adjuvants is performed without prior examination of the effects on bees. Nevertheless, recent laboratory studies evidence that adjuvants can have a toxicity increasing effect when mixed with insecticides. Therefore, this semi-field study aims to test whether an OSS mixed with insecticides can influence the insecticidal activity causing increased effects on bees and bee colonies under more realistic exposure conditions. To answer this question a pyrethroid (Karate Zeon) and a carbamate (Pirimor Granulat) were applied in a highly bee attractive crop (oil seed rape) during bee flight either alone or mixed with the OSS Break-Thru S 301 at field realistic application rates. The following parameters were assessed: mortality, flower visitation, population and brood development of full-sized bee colonies. Our results show that none of the above mentioned parameters was significantly affected by the insecticides alone or their combination with the adjuvant, except for a reduced flower visitation rate in both carbamate treatments (Tukey-HSD, p < 0.05). This indicates that the OSS did not increase mortality to a biologically relevant extent or any of the parameters observed on honey bees and colonies in this trial. Hence, social buffering may have played a crucial role in increasing thresholds for such environmental stressors. We confirm that the results of laboratory studies on individual bees cannot necessarily be extrapolated to the colony level and further trials with additional combinations are required for a well-founded evaluation of these substances.

“A People before Useless”: Ethnic Cleansing in the Wartime Hudson Valley, 1754–1763

abstract: This article investigates the issue of ethnic cleansing against Native peoples in early America and the relationship between ethnic cleansing and genocide. It examines the efforts of colonial officials in New York and New Jersey to remove Native groups in the Hudson Valley region during the Seven Years’ War. In an atmosphere of suspicion and animosity, colonial authorities first sought to exert control over local Natives through surveillance and internment in colonial towns. Then, following an outburst of genocidal violence from ordinary colonials, they began to encourage the Natives to leave their homelands, first for refuge among the Mohawk allies of the British and then for Native settlements in the distant Susquehanna country. Cast as an effort at paternalistic protection of vulnerable Natives, the official effort at ethnic cleansing worked in tandem with indiscriminate violence from ordinary colonial, as officials both exploited and exaggerated the genocidal attitudes of the colonial population to encourage Native removal. Though colonial officials abandoned this ethnic cleansing program after the return of peace to the region in 1758, the evidence presented here shows that largely nonviolent efforts at removal or ethnic cleansing cannot easily be disentangled from the threat of genocide or extermination.

Effect of Fumagilin-B treatment timing on nosema (Vairimorpha spp.; Microspora: Nosematidae) abundance and honey bee (Hymenoptera: Apidae) colonies under winter management in the Canadian Prairies.

Fumagilin-B is used to treat nosema infection in honey bee colonies; however, it is unclear whether treatment consistently reduces Vairimorpha ceranae (Fries et al.) abundance and improves colony strength and survival in the Canadian Prairies. This study assessed spring and fall fumagillin treatments on nosema abundance, colony strength, and mortality in 2 different beekeeping regions within Alberta, using both indoor and outdoor wintering management at each site. We compared 4 fumagillin treatments: Spring-only, Fall-only, Spring-and-Fall, and Control (no treatment). The spring treatment dose was ~68 mg/colony, whereas the fall treatment dose was 120 or 48 mg/colony, depending on the year. We found that the colonies were infected predominately with V. ceranae, with V. apis (Zander) present only in mixed infections in a subset of colonies. Although treatment in either the spring or fall did reduce nosema abundance in the short term, it did not eliminate the infection, making continued monitoring necessary. Colony strength was improved by spring treatment in some locations but not consistently, possibly due to the treatment timing or low dose. The combined spring and fall treatment increased colony survival over winter in one of 2 yr. Wintering method did not interact with treatment to affect nosema abundance in the spring. There does not appear to be a significant residual benefit of fall treatment as it did not reduce spring nosema abundance or increase colony population. Therefore, spring treatment should be applied to reduce spring V. ceranae abundance rather than relying on residual efficacy from previous fall treatments.

Population genetics comparison of Lilioceris cheni (Coleoptera: Chrysomelidae) colonies released onto Dioscorea bulbifera in Southeastern U.S.A.

ABSTRACT Multiple importations of Lilioceris cheni, a defoliating beetle of the invasive air potato plant, were received by the ARS-Invasive Plant Research Laboratory from 2002 to 2012. The last two, in 2011 (China) and 2012 (Nepal), formed the basis of two colonies from which releases were made into six Southeastern U.S. States. Colony populations were examined using the mitochondrial COI sequence. Phylogenetics, evolutionary divergence, a haplotype network, population statistics, and migration models were generated for the two colonies, countries of origin, and the inferred populations (clades). Phylogenetics eliminated the possibility of cryptic speciation and alleviated the need for host-range testing of the 2012 Nepalese samples. Evolutionary divergence showed the Chinese colony was 1.65X as divergent as the Nepalese, but one Nepalese clade was the most distinctly different of all clades. AMOVA showed most (>70%) genetic variation resided within rather than between colonies. In contrast, AMOVAs showed high levels (>61.5%) of genetic variation between underlying clades with proportionally less variation within. The haplotype network showed broad agreement with the phylogeny. Clade C, from China, displayed the largest number of haplotypes and the largest mutation-scaled effective population size in MIGRATE software. The best MIGRATE models indicated that migration and descent followed the order of phylogenetic descent. The results suggest that the genetic diversity being offered to the adventive range by these very divergent colonies (and clades) is large and should support great ecological flexibility.

Composition of different castes in the subterranean termite Odontotermes horni (Wasmann) nest

An investigation was conducted at GKVK in Bengaluru, India, to study the composition of subterranean termite nests built by Odontotermes horni. The study revealed that eggs were found in groups on the primary depository, while nymphs of workers, soldiers, and alates were observed in the fungus combs. The nymphs formed most of the colony population, with workers being more numerous and dimorphic with major and minor forms. Soldiers were found to be associated with the workers as guards during various activities. The royal pair (king and queen) was situated in the royal chamber, with two queens and a king observed in one of the nests. The king and physogastric queen measured 12.6 and 61.5 mm in length, respectively. Adult alates were seen in the alate waiting chamber before emergence.

THE BRITISH IN THE BAY: OCCUPATIONAL STRESS AND BIOLOGICAL DISPARITIES

THE BRITISH IN THE BAY: OCCUPATIONAL STRESS AND BIOLOGICAL DISPARITIES