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¿Hay opciones personalizadas para macetas plásticas por mayor?

Sí, muchos proveedores y fabricantes ofrecen opciones personalizadas para macetas plásticas al por mayor. Estas opciones permiten adaptar las macetas a las necesidades específicas de los clientes, ya sea con respecto al tamaño, diseño, color, logotipo u otros detalles. Aquí hay algunas formas en que puedes personalizar macetas plásticas al por mayor:

  1. Impresión de Logotipo o Etiqueta: Puedes solicitar la impresión del logotipo de tu empresa o una etiqueta personalizada en las macetas. Esto es ideal para eventos promocionales, regalos corporativos o para impulsar la marca.
  2. Colores Personalizados: Algunos proveedores permiten la personalización del color de las macetas. Puedes elegir colores que se alineen con la identidad de tu marca o que se adapten al tema de tu proyecto.
  3. Tamaños y Formas Específicas: Si necesitas tamaños o formas específicas que no están disponibles en el inventario estándar, muchos proveedores pueden personalizar las macetas según tus especificaciones.
  4. Materiales Específicos: Puedes solicitar macetas plásticas fabricadas con materiales específicos que se adapten a tus necesidades, como plásticos reciclados, biodegradables u otros materiales ecológicos.
  5. Diseños Especiales: Si tienes un diseño específico en mente, algunos fabricantes pueden trabajar contigo para crear macetas con diseños únicos,macetas 7 litros patrones o características especiales.
  6. Agregado de Funcionalidades Especiales: Algunos proveedores ofrecen opciones personalizadas, como macetas con sistemas de riego automático, compartimentos adicionales, o características específicas para facilitar el cuidado de las plantas.
  7. Embalaje Personalizado: Además de personalizar las macetas en sí, puedes solicitar un embalaje personalizado que refleje tu marca o incluya información específica.

Antes de solicitar opciones personalizadas, es importante comunicarte directamente con los proveedores, discutir tus requisitos y confirmar los detalles del proceso de personalización. Además, ten en cuenta que las opciones y los costos pueden variar según el proveedor y la cantidad solicitada.

Reliance on biotechnology can increase the risk of forward biological contamination

Trace elements and small-usage compounds can be transported from Earth, or in some cases extracted from the Martian regolith. In the case where power is provided from photocollection or photovoltaics, light energy will vary with location and season, and may be critical to power our bioreactors. Although photosynthetic organisms are attractive for FPS, a higher demand for carbon-rich feedstocks and other chemicals necessitates a more rapid and efficient CO2 fixation strategy. Physicochemical conversion is inefficient due to high temperature and pressure requirements. Microbial electrosynthesis , whereby reducing power is passed from abiotic electrodes to microbes to power CO2 reduction, can offer rapid and efficient CO2 fixation at ambient temperature and pressure . MES can produce a variety of chemicals including acetate , isobutanol , PHB , and sucrose , and therefore represents a filexible and highly promising ISRU platform technology . Biological N2-fixation offers power- and resource-efficient ammonium production. Although photoautotrophic N2 fixation with, for example, purple non-sulfur bacteria, is possible, slow growth rates due to the high energetic demand of nitrogenase limit throughput . Therefore, heterotrophic production with similar bacteria using acetate or sucrose as a feed stock sourced from electromicrobial CO2-fixation represents the most promising production scheme, and additionally benefits from a high degree of process redundancy with heterotrophic bioplastic production. Regolith provides a significant inventory for trace elements and, when mixed with the substantial cellulosic biomass waste from FPS processes, can facilitate recycling organic matter into fertilizer to support crop growth. However, regolith use is hampered by widespread perchlorate , indicating that decontamination is necessary prior to enrichment or use. Dechlorination can be achieved via biological perchlorate reduction using one of many dissimilatory perchlorate reducing organisms . Efforts to reduce perchlorate biologically have been explored independently and in combination with a more wholistic biological platform . Such efforts to integrate synthetic biology into human exploration missions suggest that a number of approaches should be considered within a surface bio-manufactory.

A biomanufactory must be able to produce and utilize feed stocks along three axes as depicted in Figure 5: CO2-fixation to supply a carbon and energy source for downstream heterotrophic organisms or to generate commodity chemicals directly, N2-fixation to provide ammonium and nitrate for plants and non-diazotrophic microbes,macetas para viveros and regolith decontamination and enrichment for soil-based agriculture and trace nutrient provision. ISRU inputs are sub-module and organism dependent, with all sub-modules requiring water and power. For the carbon fixation sub-module , CO2 is supplied as the carbon source, and electrons are supplied as H2 or directly via a cathode. Our proposed bio-catalysts are the lithoautotrophic Cupriavidus necator for longer-chain carbon production [e.g., sucrose ] and the acetogen Sporomusa ovata for acetate production. C. necator is a promising chassis for metabolic engineering and scale-up , with S. ovata having one of the highest current consumptions for acetogens characterized to date . The fixed-carbon outputs of this sub-module are then used as inputs for the other ISRU sub-modules in addition to the ISM module . The inputs to the nitrogen fixation sub-module include fixed carbon feed stocks, N2, and light. The diazotrophic purple-non sulfur bacterium Rhodopseudomonas palustris is the proposed bio-catalyst, as this bacterium is capable of anaerobic, light-driven N2 fixation utilizing acetate as the carbon source, and has a robust genetic system allowing for rapid manipulation . The output product is fixed nitrogen inthe form of ammonium, which is used as a feed stock for the carbon-fixation sub-module of ISRU along with the FPS and ISM modules. The inputs for the regolith enrichment sub-module include regolith, fixed carbon feedstocks, and N2. Azospira suillum is a possible bio-catalyst of choice due to its dual use in perchlorate reduction and nitrogen fixation . Regolith enrichment outputs include soil for the FPS module , H2 that can be fed back into the carbon fixation sub-module and the ISM module, chlorine gas from perchlorate reduction, and waste products. Replicate ISRU bioreactors operating continuously in parallel with back-up operations lines can ensure a constant supply of the chemical feed stocks, commodity chemicals, and biomass for downstream processing in ISM and FPS operations. Integration of ISRU technologies with other biomanufactory elements, especially anaerobic digestion reactors, may enable complete recyclability of raw materials, minimizing resource consumption and impact on the Martian environment .

Waste stream processing to recycle essential elements will reduce material requirements in the biomanufactory. Typical feed stocks include inedible crop mass, human excreta, and other mission wastes. Space mission waste management traditionally focuses on water recovery and efficient waste storage through warm air drying and lyophilization . Mission trash can be incinerated to produce CO2, CO, and H2O . Pyrolysis, another abiotic technique, yields CO and H2 alongside CH4 . The Sabatier process converts CO2 and CO to CH4 by reacting with H2. An alternate thermal degradation reactor , operating under varying conditions that promote pyrolysis, gasification, or incineration, yields various liquid and gaseous products. The fact remains however, that abiotic carbon recycling is inefficient with respect to desired product CH4, and is highly energy-intensive. Microbes that recover resources from mission wastes are a viable option to facilitate loop closure. Aerobic composting produces CO2 and a nutrient-rich extract for plant and microbial growth . However, this process requires O2, which will likely be a limited resource. Hence, anaerobic digestion, a multi-step microbial process that can produce a suite of endproducts at lower temperature than abiotic techniques , is the most promising approach for a Mars biomanufactory to recycle streams for the ISM and FPS processes. Digestion products CH4 and volatile fatty acids can be substrates for polymer-producing microbes . Digestate, with nutrients of N, P, and K, can be ideal for plant and microbial growth , as shown in Figure 6. Additionally, a CH4 and CO2 mixture serves as a biogas energy source, and byproduct H2 is also an energy source . Because additional infrastructure and utilities are necessary for waste processing, the extent of loop closure that is obtainable from a treatment route must be analyzed to balance yield with its infrastructure and logistic costs. Anaerobic digestion performance is a function of the composition and pretreatment of input waste streams , as well as reaction strategies like batch or continuous, number of stages, and operation conditions such as organic loading rate, solids retention time, operating temperature, pH, toxic levels of inhibitors and trace metal requirements . Many of these process parameters exhibit trade-offs between product yield and necessary resources. For example, a higher waste loading reduces water demand, albeit at the cost of process efficiency. There is also a potential for multiple co-benefits of anaerobic digestion within the biomanufactory. Anaerobic biodegradation of nitrogen-rich protein feed stocks, for example, releases free NH3 by ammonification. While NH3 is toxic to anaerobic digestion and must thus be managed , it reacts with carbonic acid to produce bicarbonate buffer and ammonium, decreasing CO2 levels in the biogas and buffering against low pH.

The resulting digestate ammonium can serve as a fertilizer for crops and nutrient for microbial cultures.FPS and ISM waste as well as human waste are inputs for an anaerobic digester, with output recycled products supplementing the ISRU unit. Depending on the configuration of the waste streams from the biomanufactory and other mission elements, the operating conditions of the process can be varied to alter the efficiency and output profile. Open problems include the design and optimization of waste processing configurations and operations, and the identification of optimal end-product distributions based on a loop closure metric against mission production profiles, mission horizon, biomanufacturing feedstock needs, and the possible use of leftover products by other mission elements beyond the bio-manufactory. A comparison with abiotic waste treatment strategies is also needed, checking power demand, risk, autonomy, and modularity benefits.Biomanufactory development must be done in concert with planned NASA missions that can provide critical opportunities to test subsystems and models necessary to evaluate efficacy and technology readiness levels . Figure 7 is our attempt to place critical elements of a biomanufactory road map into this context. We label critical mission stages using Reference Mission Architecture -S and RMA-L,macetas por mayor which refer to Mars surface missions with short and long durations, respectively.Beyond contamination, there are ethical issues that concern both the act of colonizing a new land and justifying the cost and benefits of a mission given needs of the many here on earth. Our road map begins with the call for an extensive and ongoing discussion of ethics . Planetary protection policies can provide answers or frameworks to address extant ethical questions surrounding deep-space exploration, especially on Mars . Critically, scientists and engineers developing these technologies cannot be separate or immune to such policy development.We have outlined the design and future deployment of a biomanufactory to support human surface operations during a 500 days manned Mars mission. We extended previous stand-alone biological elements with space use potential into an integrated biomanufacturing system by bringing together the important systems of ISRU, synthesis, and recycling, to yield food, pharmaceuticals, and bio-materials. We also provided an envelope of future design, testing, and biomanufactory element deployment in a road map that spans Earth-based system development, testing on the ISS, integration with lunar missions, and initial construction during shorter-term initial human forays on Mars. The innovations necessary to meet the challenges of low-cost, energy and mass efficient, closed-loop, and regenerable bio-manufacturing for space will undoubtedly yield important contributions to forwarding sustainable bio-manufacturing on Earth. We anticipate that the path towards instantiating a biomanufactory will be replete with science, engineering, and ethical challenges. But that is the excitement—part-and-parcel—of the journey to Mars.Rose production is currently the largest component of California’s $300 million cut-flower industry. In 2001, California growers produced 66% of the U.S. rose crop, with a wholesale value of $45 million . The key pests of cut roses are two spotted spider mites , western flower thrips and rose powdery mildew . The two spotted spider mite is a foliage feeder that extracts the cell contents from leaves. This feeding causes foliar stippling and can disrupt the plant’s photosynthetic and water balance mechanisms . The western flower thrips is both a foliage and flower feeder, although it feeds primarily on flowers in the cut-rose system . Powdery mildew is probably the most widespread and best-known disease of roses. The fungus produces a white, powdery-appearing growth of mycelium and conidia on leaves, which can cause distortion, discoloration and premature senescence. Although it causes some disruption of photosynthesis and transpiration control, the key impact of powdery mildew is reduced aesthetic value caused by the white, powdery spots and leaf distortion. Fresh cut roses are often harvested twice daily, so revised reentry intervals imposed by the U.S. Environmental Protection Agency after pesticide application limit the number of pesticides that are useful in this production system . In addition, the typical number of pesticide sprays applied to roses grown for cut flowers has impeded the implementation of integrated pest management procedures, particularly the use of biological controls. The IPM approach to pest management incorporates all cost-effective control tactics appropriate for the crop, including biological, cultural and chemical controls. Pesticides that target hard-to-kill floriculture pests frequently kill natural enemies as well, which favors continued reliance on conventional pesticides while discouraging the adoption of biological control. Heavy pesticide use against key pests in the greenhouse has resulted in the widespread development of pesticide resistance in western flower thrips , mites , white flies , aphids and leaf miners . The heavy use of pesticides in cut roses is also a worker safety concern in global and local production. California rose growers reached a crisis point about 8 years ago, when pesticide resistance, costs and limited pesticide availability threatened the growers’ ability to effectively manage two spotted spider mites. At the same time, a new cut-rose production system that favors the success of IPM was gaining widespread acceptance. Roses were traditionally grown in soil with a hedgerow training system, where flowers are cut in a manner that gradually creates a 7-foot or taller hedge. The hedges are pruned back annually to about a 3-foot height and the process is begun again.

A record of agricultural burn events was provided by the Air Pollution Control District

Our study found that the incidence of drift-related pesticide poisoning was higher among female and younger agricultural workers and in western states. These groups were previously found to have a higher incidence of pesticide poisoning . It is not known why the incidence is higher among female and younger agricultural workers, but hypotheses include that these groups are at greater risk of exposure, that they are more susceptible to pesticide toxicity, or that they are more likely to report exposure and illness or seek medical attention. However, we did not observe consistent patterns among workers in other occupations. This finding requires further research to identify the explanation. The higher incidence in the western states may suggest that workers in this region are at higher risk of drift exposure; however, it may also have resulted from better case identification in California and Washington states through their higher staffed surveillance programs, extensive use of workers’ compensation reports in these states, and use of active surveillance for some large drift events in California. Nonoccupational exposure. This study found that more than half of drift-related pesticide poisoning cases resulted from nonoccupational exposures and that 61% of these nonoccupational cases were exposed to fumigants. California data suggest that residents in agriculture-intensive regions have a 69 times higher risk of pesticide poisoning from drift exposure compared with other regions. This may reflect California’s use of active surveillance for some large drift events. Children had the greatest risk among nonoccupational cases. The reasons for this are not known but may be because children have higher pesticide exposures,macetas por mayor greater susceptibility to pesticide toxicity, or because concerned parents are more likely to seek medical attention. Recently several organizations submitted a petition to the U.S. EPA asking the agency to evaluate children’s exposure to pesticide drift and adopt interim prohibitions on the use of drift-prone pesticides near homes, schools, and parks . Contributing factors. Soil fumigation was a major cause of large drift events, accounting for the largest proportion of cases.

Because of the high volatility of fumigants, specific measures are required to prevent emissions after completion of the application. Given the unique drift risks posed by fumigants, U.S. EPA regulates the drift of fumigants separately from non-fumigant pesticides. The U.S. EPA recently adopted new safety requirements for soil fumigants, which took effect in early 2011 and include comprehensive measures designed to reduce the potential for direct fumigant exposures; reduce fumigant emissions; improve planning, training, and communications; and promote early detection and appropriate responses to possible future incidents . Requirements for buffer zones are also strengthened. For example, fumigants that generally require a > 300 foot buffer zone are prohibited within 0.25 miles of “difficult to-evacuate” sites . We found that, of the 738 fumigant-related cases with information on distance, 606 occurred > 0.25 miles from the application site, which suggests that the new buffer zone requirements, independent of other measures to increase safety, may not be sufficient to prevent drift exposure. This study also shows the need to reinforce compliance with weather-related requirements and drift monitoring activities. Moreover, applicators should be alert and careful, especially when close to non-target areas such as adjacent fields, houses, and roads. Applicator carelessness contributed to 79 events , of which 56 events involved aerial applicators. Aerial application was the most frequent application method found in drift events, accounting for 249 events . Drift hazards from aerial applications have been well documented . Applicators should use all available drift management measures and equipment to reduce drift exposure, including new validated drift reduction technologies as they become available. Limitations. This study requires cautious interpretation especially for variables with missing data on many cases . This study also has several limitations. First, our findings likely underestimate the actual magnitude of drift events and cases because case identification principally relies on passive surveillance systems. Such under reporting might have allowed the totals to be appreciably influenced by a handful of California episodes in which active case finding located relatively large numbers of affected people. Pesticide-related illnesses are under reported because of individuals not seeking medical attention , misdiagnosis, and health care provider failure to report cases to public health authorities . Data from the National Agricultural Workers Survey suggests that the pesticide poisoning rates for agricultural workers may be an order of magnitude higher than those identified by the SENSOR-Pesticides and PISP programs . Second, the incidence of drift cases from agricultural applications may have been underestimated by using crude denominators of total population and employment estimates, which may also include those who are not at risk. On the other hand, the incidence for agricultural workers may have been overestimated if the denominator data under counted undocumented workers. Third, the data may include false-positive cases because clinical findings of pesticide poisoning are nonspecific and diagnostic tests are not available or rarely performed. Fourth, when we combined data from SENSOR-Pesticides and PISP, some duplication of cases and mis-classification of variables may have occurred, although we took steps to identify and resolve discrepancies.

Also, SENSOR-Pesticides and PISP may differ in case detection sensitivity because the two programs use slightly different case definitions. Lastly, contributing factor information was not available for 48% of cases, either because an in-depth investigation did not occur or insufficient details were entered into the database. We often based the retrospective coding of contributing factors on limited data, which may have produced some misclassification.Burning fields to remove crop stubble, weeds and pests occurs worldwide, and California’s estimated emissions from the burning of crop residue ranks fifth nationally . These emissions potentially contribute to particulate matter levels in the San Joaquin Valley, which often exceed standards for ambient air each season of the year . Studies have documented thousands of chemicals in smoke; they can exist in gas, liquid and solid form. During burning, plant matter breaks apart and gases condense on particles or form particles. Most particulate matter in smoke is smaller than 2.5 micrometers in diameter and can be transported over long distances . The California Air Resources Board estimates annual tons of particulate matter and gases emitted from field, orchard and weed burning for California counties ; their estimates are derived from burns of crop residue in a laboratory . Studies have documented emissions of 14 semivolatile polycyclic aromatic hydrocarbons , the most abundant of which is naphthalene . A respiratory carcinogen , naphthalene is predominantly found in the gas phase of air sampling, with the remainder measured in the particulate phase . Few ambient air monitoring studies have been conducted in the United States during agricultural burns, either adjacent to burns or in towns and communities . Educational efforts for the general public have mostly focused on smoke from wildfires and have included public health recommendations for those exposed to elevated particulate matter and visibility guidelines for those air levels . CARB has also distributed a lengthy educational pamphlet for farmers . However, it was unknown whether health educational outreach efforts specifically targeting agricultural burning were needed. Particulate matter emissions from field burning in Imperial County — a rural desert county in California’s southeast corner — rank among the highest for any county in the state . The agricultural area of Imperial County is anirrigated desert valley, where a variety of crops including vegetables, hay and grain are grown . Fields of bermudagrass, which is grown both for hay and seed, are burned primarily in the winter, while wheat stubble is burned during the summer. Less than 3% of homes in Imperial County use wood as a house heating fuel . During the winter when night temperatures drop, inversions commonly occur; cooler ground level air, including pollutants, are trapped near the Earth’s surface by an upper layer of warmer air. For fields to be burned,macetas por mayor plastico the Air Pollution Control District requires that the estimated inversion layer must be at 3,000 feet or higher, and the burn must be initiated between 10 a.m. and 3 p.m. Farmers who have applied for burn permits are usually notified by the district the day before the targeted burn date that their fields may be burned. Thus, our air monitoring studies required methods that could be rapidly deployed. Our methods and results are described in greater detail in a report to the funding agency .We selected three schools and one church based on their proximity to burns in previous years and installed portable Environmental Beta Attenuation Monitors . We measured hourly average concentrations of PM2.5 and meteorological variables for 69 days starting on Jan. 14, 2009. E-BAM PM2.5 measurements are not recognized as a Federal Equivalent Method or a Federal Reference Method , one of which is required to determine if levels legally exceed air standards. However, E-BAM measurements have proven comparable to FRM measurements in field tests .

During the E-BAM monitoring period, 15,686 acres were burned on 35 allowable burn days; the acreage burned daily ranged from 0 to 1,400 acres. Average 24-hour PM2.5 concentrations were highest — 12 micrograms per cubic meter — at the northern station and lowest at the western station . The lower levels in Seeley may have been because the predominant wind direction was from the west, and sources of pollution, including burned fields, were predominantly to the east of the Seeley station. All daily PM2.5 levels were below the federal standard for unhealthy air, 35 µg per cubic meter. However, at the Calipatria station the 95th percentile of 24-hour concentrations was above 16 µg per cubic meter, which corresponds to moderate air quality where “aggravation of heart or lung disease in people with cardiopulmonary disease and older adults” is possible . We also compared 8-hour average PM2.5 concentrations at the four locations. There was little difference during the day , with levels slightly lower on field-burn days compared to no field-burn days . In contrast, from the early evening to the morning of the next day , average PM2.5 concentrations on field-burn days were 23% higher than on no-field-burn days. Additionally, on days when there was an agricultural burn within 2 miles of the Calipatria station , during the evening-to-morning period the average 8-hour concentrations were 19.5 to 20.7 µg per cubic meter, 170% higher than on days when there were no burns within 2 miles . Following the burns near the Calipatria station, on the subsequent 2 days when there were no additional burns , the evening-to-morning levels remained slightly above levels on days with no burns . Higher particulate matter levels from evening-to-morning hours associated with agricultural burning in Imperial County are consistent with air pollution dynamics. Air pollutants may rise during the day as the Earth’s surfaces are heated and then be brought down to ground level by the descent of an evening inversion layer. The night and next-day accumulation of smoke is described in a CARB pamphlet for farmers .We monitored five specific burns of 65 to 150 acres of bermudagrass stubble during the E-BAM monitoring period. For four burns, ground-level winds were low at 2 to 3 miles per hour , and the plume from the burn rose up to the apparent height of the inversion layer where it was observed to spread out, sometimes in the opposite direction of the ground wind direction. The ground-level plumes dispersed within about an hour, but the upper plumes remained visible, apparently limited by the inversion layer, until sunset. At one of the five burns, the Dunham burn, the wind speed was higher , and the ground-level smoke plume engulfed a house on the same property as the burned field and drifted onto an adjacent field. We deployed portable particulate matter monitors — active-flow and passive personal DataRAM nephelometers — which continuously measured PM2.5 and PM10 , respectively. This monitoring was done at three locations surrounding each of the five burns for 24 to 72 hours. Two locations were near the burns and were places of public access, homes or telephone poles; the other was at the nearest E-BAM, which was farther away . At the 15 locations, field difficulties including power outages, supply delivery problems and apparent equipment or software malfunctions limited monitoring to 11 and 13 locations for the PM2.5 and PM10 nephelometers, respectively.

Suppose that the polygyny threshold in equation were satisfied by an equality

In order to produce analytically tractable results, we simplify by assuming throughout that there are only two types of males, rich and poor, with rich males being a fraction u of the population. All rich are identical, as are all poor. The rich males are indexed by r and the poor by p. We now demonstrate two theoretical results with the potential to resolve the polygyny paradox. First, diminishing returns to additional wives arising from causes other than necessity to share a husband’s rival material wealth will reduce the number of wives acquired by each rich male. Second, because of this fact, a highly unequal wealth distribution with few extraordinarily rich men may produce little polygyny, while a less unequal wealth distribution with a larger fraction of rich men may produce a greater extent of polygyny. Two rich men, for example, can be expected to have more wives in total than one very rich man whose wealth equals their combined wealth. For this same reason, the Gini coefficient—see table 2 for a definition—is not a sufficient statistic for the analysis of the relationship between polygyny and wealth inequality. We take up each of these results, in turn, before assessing if our empirical estimates are consistent with this explanation.If we assume that male demand is limiting, then equation determines the number of wives each rich man will have. It is clear from inspection of equation that a greater extent of diminishing fitness returns to additional wives produces a lower male demand for additional wives. This is demonstrated mathematically in the electronic supplementary material. Determining the effect of greater diminishing returns to additional wives when female supply is limiting is more challenging. As noted above, if female supply is limiting,1 litre square plant pots the value of n* implied by the polygyny threshold inequality in equation has no closed form solution.

To address this challenge, we proceed as follows.Then a reduction in d, holding all other terms constant, would reduce the right-hand side of the equation—the fitness of each of the n wives of a rich man—while having no effect on the left-hand side—the fitness of a singleton wife. Thus, holding all else equal, an offsetting decrease in n would be required to restore the equality. This is demonstrated in the electronic supplementary material by differentiating equation with respect to d. This means that a man who was just barely rich enough so that an unpaired woman would choose to marry him as wife number under the initial d, would, under the lower d, be unable to secure the unpaired woman’s partnership. As such, an increase in the extent of diminishing returns to additional wives will reduce both male demand for, and female supply to, polygynous marriage. Our results imply that if d , 1, a larger quantity of moderately rich men can be expected to have more wives in total than a smaller quantity of even richer men, holding constant the total wealth held by the rich across these cases. This first finding will interact with our second finding, discussed below, concerning the effects of the population density of the rich class of men on the frequency of polygyny and the level of wealth inequality. In the electronic supplementary material, we present an alternative approach to account for diminishing marginal returns to increasing number of wives and find that our insights do not depend on the specific way in which diminishing fitness returns to increasing number of wives are modelled.To address prediction P1, we present empirical estimates of m and d . These values are estimated using a multi-level regression model fit to our individual level data; methodological details are provided in the electronic supplementary material. In all but four of the populations in our sample, the estimated d coefficient is reliably less than 1. This result provides cross-cultural empirical support for the first of the two conditions needed to generate a transition to a greater degree of monogamy with increasing wealth inequality.

Note two further results also shown in figure 5. First, our estimates for m are quite low, particularly across the agricultural economies. Second, our estimates of d 2 m are positive in almost all populations, including those that are concurrently polygynous and those that are serially monogamous. The consistently small values of m across all of our samples, even the monogamous ones, was unexpected. However, these low values reflect changes in male fitness per wife. Because of biological limits to the rate of reproduction in human females, significant increases to wealth are constrained to have less than proportional effects on fitness per wife. The effects observed here are more likely to reflect the ability of males with more than a threshold level of resources per wife to minimize offspring mortality, rather than to significantly enhance their own fertility. Though not discussed in detail here, our data suggest that male wealth impacts male fitness primarily by increasing the rate of wife acquisition rather than by increasing reproductive success per wife . Our second point addresses the possible concern that our estimates of d may be low, in part, because we use times married as our measure of polygyny. While it is true that men can accumulate a greater maximal number of marriage years through concurrent polygyny than serial monogamy, figure 5a demonstrates that the use of times married is an appropriate measure of polygyny for our purposes. Across almost all populations, the elasticity of fitness with respect to times married, d 2 m, is positive and reliably non-zero. Because these estimates measure the population-specific effects of cumulative number of wives on reproductive success, they demonstrate that an increased number of marriages leads to increased reproductive success in both types of marriage systems—concurrently polygynous and serially monogamous.We have established that there exists a strong cross-cultural pattern of decreasing—but reliably non-zero—fitness returns to increasing number of wives for reasons beyond rival wealth sharing.

We now turn our attention to testing if the transition to agriculture is associated with a decreasing fraction of wealthy males. In our theoretical model, we assume a discrete two-class wealth distribution, but empirical wealth data typically have continuous distributions. To deal with this issue, we consider two proxy measures for per cent rich in our empirical data: the minimum percentage of men that account for a fraction f of the total wealth and the frequency of men with more than c wealth, where c is the empirical midpoint in each population between the average wealth of males with one wife and the average wealth of males with two wives. More details about these metrics are included in the electronic supplementary material. Table 3 provides population-level posterior estimates of the completed wealth and completed polygyny measures, with the mean estimates by subsistence type shown in the bottom panel. To address prediction P2, we calculate empirical estimates of the fraction of rich men by production system . We find that agricultural populations have a significantly reduced frequency of wealthy individuals relative to horticultural populations. All four panels show reliable differences in mean per cent rich between the horticultural and agricultural subsistence modes. This lesser fraction of wealthy individuals suggests a decreased number of men both able and willing to take second wives. This in turn leads to reduced levels of per cent female polygyny in contexts where large wealth differentials are not able to underwrite large differentials in wives due to the existence of diminishing fitness returns to such additional wives. A limitation of this last result is that it is based on data from only four agricultural populations, three of them concentrated in a restricted region and time period . Moreover, a more informative dataset would come not from agricultural populations in the time period between the 1700s and 2000s, but rather from the agricultural populations in which monogamy actually began to emerge denovo. In our main analysis, we use estimates derived from the individual-level records available in the populations shown in table 1; in the electronic supplementary material,macetas por mayor we present comparable analyses that include 14 additional wealth distributions from historical agricultural populations. The results of this supplementary analysis are consistent with our arguments here—and in fact show stronger and more reliable effects in the direction predicted by P2. These supplementary data, however, are based on sometimes contested reconstructions of the historical wealth distributions pieced together by archaeologists and economic historians;they must be appreciated within the constraints associated with such forms of data.Using individual-level data from 29 populations, we show evidence of a general cross-cultural pattern of decreasing marginal fitness returns to increasing number of marriages. Further, using these same 29 datasets , we demonstrate the existence of an increasingly skewed distribution of material wealth in class-based agricultural societies . Both of these empirical findings are consistent with our model-based explanation for the decline of polygyny in societies engaged in agricultural production.We use cross-cultural data and a new mutual mate choice model to propose a resolution to the polygyny paradox. Following Oh et al., we extend the standard polygyny threshold model to a mutual mate choice model that accounts for both female supply to, and male demand for, polygynous matchings, in the light of the importance of, and inequality in, rival and non-rival forms of wealth.

The empirical results presented in figures 5 and 6 demonstrate two phenomena that are jointly sufficient to generate a transition to more frequent monogamy among populations with a co-occurring transition to a more unequal, highly stratified, class-based social structure. In such populations, fewer men can cross the wealth threshold required to obtain a second wife, and those who do may be fabulously wealthy, but—because of diminishing marginal fitness returns to increasing number of marriages—do not acquire wives in full proportion to their capacity to support them with rival wealth. Together, these effects reduce the population-level fraction of wives in polygynous marriages. Our model demonstrates that a low population-level frequency of polygyny will be an equilibrium outcome among fitness maximizing males and females in a society characterized by a large class of wealth-poor peasants and a small class of exceptionally wealthy elite. Our mutual mate choice model thus provides an empirically plausible resolution to the polygyny paradox and the transition to monogamy which co-occurred with the rise of highly unequal agricultural populations. We, however, cannot yet explain the causes of the unexpectedly substantial decreasing marginal fitness returns to increasing number of marriages. A purely statistical explanation of our results could be that we have missed some important rival form of wealth, which if accounted for would result in a larger estimate for m and hence a reduced estimate of the degree of diminishing returns to additional wives for reasons other than the sharing of rival wealth. Another possibility, already mentioned, is that in some of our datasets the very wealthy could be deliberately limiting their reproductive success , which would also drive m downwards. In addition to these possible statistical effects, there are a number of other plausible causes of the diminishing returns to additional wives observed in our populations. One possibility is that a male’s time and attention are rival inputs to his own fitness. This situation is likely to arise when paternal investment is essential to offspring survival and well-being. A male’s time can also be rival in other fitness relevant ways. For example, it may be difficult for a single wealthy man to effectively mate guard a large number of wives. With a wealth ratio of mr ¼ 2 and a per cent rich of u ¼ 0.5, a single rich man will have to monopolize his two wives in the face of challenges from a single unmarried man on average; however, with a wealth ratio of mr ¼ 10 and a per cent rich of u ¼ 0.1, a single rich man will have to defend his 10 wives from nine unmarried men on average. As the wealth ratio grows even more skewed, this situation could become increasingly difficult to manage . A related possibility is that a growing number of unmarried men could socially censure wealthy polygynous males, imposing costs on them that reduce male demand for and/or female supply to polygynous marriage. A third possibility is that sexually transmitted infection burden could diminish returns to polygyny, if polygyny enhances infection rates.