968 resultados para tidal asymmetry
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Synchronization in the events of the reproductive cycle in female Neohelice granulata Dana, 1851 were studied from samples taken weekly and biweekly from September to December 2006 in the Laguna Mar Chiquita. The timing and larval hatching and synchronicity were inferred from numbers of ovigerous females and observing the stages of embryonic development. Synchronization in larval hatching also was observed in females in experiments in dark for a period of 48 hours, at three different salinities (10, 23 and 33 ppm). In addition plankton sampling were performed in order to study larval exportation at the field and its link to the tidal and light/dark cycles. We found that ovigerous females of N. granulata have a marked synchronization in embryonic development which results in that most of berried females are close to hatching within a period of maximum tidal range (days). Within this period, there is a synchronization of hatching at a time scale of hours, governed by environmental conditions. The salinity range used in this study (10-32) did not affect hatching synchronicity neither time to hatch. Hatching was synchronized according to endogenous rhythms governed mainly by the tidal cycle and secondarily by the breadth of it. It is also conditioned by the light-dark cycle through an exogenous cycle, so that the hatchings would occur mostly at night high tides.
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The author studied, the horizontal and vertical distribution of most common part of the flora and fauna of the bay of Guanabara at Rio de Janeiro. In this paper the eulittoral, poly, meso and oligohaline regions were localised and studied; and the first chart of its distribution was presented (fig. 2). The salinity of superficial waters was established through determinations based on 30 trips inside the buy for collecting biological materials. Some often 409 determinations which were previous reported together with the present ones served for the eleboration of a salinity map of the bay of Guanabara (fig. 1). This map of fig. 2 shows the geographic locations of the water regions. EULITTORAL WATER REGIME Fig. 3 shows the diagram scheme of fauna and flora of this regime. Sea water salinity 34/1.000, density mean 1.027, transparent greenish waters, sea coast with moderate bursting waves. Limpid sea shore with white sand, gneiss with the big barnacle Tetraclita squamosa var. stalactifera (Lam. Pilsbry. Vertical distributions: barna¬cles layers with a green region in which are present the oyster Ostrea pa-rasitica L., the barnacles Tetraclita, Chthamalus, Balanus tintinnabulum var. tintinnabulum (L.) e var. antillensis Pilsbry in connection with several mollusca and the sea beatle Isopoda Lygia sp. Covered by water and exposed to air by the tidal ritms, there is a stratum of brown animals that is the layer of mussels Mytilus perna L., with others brown and chestnut animals : the Crustacea Pachygrapsus, the little crab Porcellana sp., the stone crab Me-nippe nodifrons Stimpson, the sea stars Echinaster brasiliensis (Mull. & Tr.), Astropecten sp. and the sea anemones Actinia sp. Underneath and never visible there is a subtidal region with green tubular algae of genus Codium and amidst its bunches the sea urchin Lycthchinus variegatus (Agass.) walks and more deeply there are numerous sand-dollars Encope emarginata (Leske). The microplancton of this regime is Ceratiumplancton. POLYHALINE WATER REGIMB Water almost sea water, but directly influenced by continental lands, with rock salts dissolved and in suspension. Salinity: 33 to 32/1.000. This waters endure the actions of the popular nicknamed «water of the hill» (as the waters of mesohaline and oligohaline regimes), becoming suddenly reddish during several hours. That pheno¬menon returns several times in the year and come with great mortality of fishes. In these waters, according to Dr. J. G. FARIA there are species of Protozoa : Peridinea, the Glenoidinium trochoideum St., followed by its satellites which he thinks that they are able to secret toxical substances which can slaughter some species of fishes. In these «waters of the hill» was found a species of Copepoda the Charlesia darwini. In August 1946 the west shore of the Guanabara was plenty of killed fishes occupying a area of 8 feet large by 3 nautical miles of lenght. The enclosure for catching fishes in the rivers mouthes presents in these periods mass dead fishes. The phenomenon of «waters of the hill» appears with the first rains after a period of long dryness. MESOHALINE WATER REGIME Fig. 4 shows the the diagramm scheme. Salt or brackish water from 30 to 17/1.000 salinity, sometimes until 10/1.000. Turbid waters with mud in suspension, chestnut, claveyous waters; shore dirty black mud without waving bursting; the waters are warmer and shorner than those of the polihaline regime. Mangrove shore with the mangrove trees : Rhizophora mangle L., Avicennia sp., Laguncularia sp., and the »cotton tree of sea» Hibiscus sp. Fauna: the great land crab «guaimú» Cardisoma guanhumi Latr., ashore in dry firm land. There is the real land crab Ucides cordatus (L.) in wetting mud and in neigh¬ bourhood of the burrows of the fiddler-crabs of genus Uca. On stones and in the roots of the Rhizophora inhabits the brightly colored mangrove-tree-crab («aratu» Portuguese nickname) Goniopsis cruentata (Latreille) and the sparingly the big oyster Ostrea rhizophorae Guild. Lower is the region of barnacles Balanus amphitrite var. communis Darwin and var. niveus Darwin; Balanus tintinnabulum var. tintinnabulum (L.) doesn't grow in this brackish water; lower is the region of Pelecipoda with prepollency of Venus and Cytherea shell-fishes and the Panopeus mud crab; there are the sea lettuce Ulva and the Gastreropod Cerithium. The Paguridae Clibanarius which lives in the empty shells of Gasteropod molluscs, and the sessile ascidians Tethium plicatum (Lesuer) appears in some seasons. In the bottom there is a black argillous mud where the «one landed shrimps» Alpheus sp. is hidden. OLIGOHALINE WATER REGIME The salinity is lower than 10/1.000. average 8/1.000. There are no barnacles and no sea-beetles Isopods of genus Lygia; on the hay of the shore there are several graminea. This brackish water pervades by mouthes of rivers and penetrates until about 3 kilometers river above. While there is some salt dissolved in water, there are some mud crabs of the genus Uca, Sesarma, Metasesarma and Chasmagnatus. The presence of floating green plants coming from the rivers in the waters of a region indicated the oligohaline waters, with low salt content because when the average of NaCl increases above 8/1.000 these plants die and become rusty colored.
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This paper investigates the role of variable capacity utilization as a source of asymmetries in the relationship between monetary policy and economic activity within a dynamic stochastic general equilibrium framework. The source of the asymmetry is directly linked to the bottlenecks and stock-outs that emerge from the existence of capacity constraints in the real side of the economy. Money has real effects due to the presence of rigidities in households' portfolio decisions in the form of a Luces-Fuerst 'limited participation' constraint. The model features variable capacity utilization rates across firms due to demand uncertainty. A monopolistic competitive structure provides additional effects through optimal mark-up changes. The overall message of this paper for monetary policy is that the same actions may have different effects depending on the capacity utilization rate of the economy.
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We use a threshold seemingly unrelated regressions specification to assess whether the Central and East European countries (CEECs) are synchronized in their business cycles to the Euro-area. This specification is useful in two ways: First, it takes into account the common institutional factors and the similarities across CEECs in their process of economic transition. Second, it captures business cycle asymmetries by allowing for the presence of two distinct regimes for the CEECs. As the CEECs are strongly affected by the Euro-area these regimes may be associated with Euro-area expansions and contractions. We discuss representation, estimation by maximum likelihood and inference. The methodology is illustrated by using monthly industrial production in 8 CEECs. The results show that apart from Lithuania the rest of the CEECs experience “normal” growth when the Euro-area contracts and “high” growth when the Euro-area expands. Given that the CEECs are “catching up” with the Euro-area this result shows that most CEECs seem synchronized to the Euro-area cycle. Keywords: Threshold SURE; asymmetry; business cycles; CEECs. JEL classification: C33; C50; E32.
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Primary ciliary dyskinesia (PCD) is an autosomal recessive disease with an incidence estimated between 1:2,000 and 1:40,000. Ciliated epithelia line the airways, nasal and sinus cavities, Eustachian tube and fallopian tubes. Congenital abnormalities of ciliary structure and function impair mucociliary clearance. As a consequence, patients present with chronic sinopulmonary infections, recurrent glue ear and female subfertility. Similarities in the ultrastructure of respiratory cilia, nodal cilia and sperm result in patients with PCD also presenting with male infertility, abnormalities of left-right asymmetry (most commonly situs inversus totalis) and congenital heart disease. Early diagnosis is essential to ensure specialist management of the respiratory and otological complications of PCD. Diagnostic tests focus on analysis of ciliary function and electron microscopy structure. Analysis is technically difficult and labour intensive. It requires expertise for interpretation, restricting diagnosis to specialist centres. Management is currently based on the consensus of experts, and there is a pressing need for randomised clinical trials to inform treatment.
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The Miocene PX1 gabbro-pyroxenite pluton, Fuerteventura, Canary Islands, is a 3.5 x 5.5 km shallow-level intrusion (0.15-0.2 GPa and 1100-1120 degrees C), interpreted as the feeder-zone to an ocean-island volcano. It displays a vertical magmatic banding expressed in five 50 to 100 metre-wide NNE-SSW trending alkaline gabbro sequences alternating with pyroxenites. This emplacement geometry was controlled by brittle to ductile shear zones, generated by a regional E-W extensional tectonic setting that affected Fuerteventura during the Miocene. At a smaller scale, the PX1 gabbro and pyroxenite bands consist of metre-thick differentiation units, which suggest emplacement by periodic injection of magma pulses as vertical dykes that amalgamated, similarly to a sub-volcanic sheeted dyke complex. Individual dykes underwent internal differentiation following a solidification front parallel to the dyke edges. This solidification front may have been favoured by a significant lateral/horizontal thermal gradient, expressed by the vertical banding in the gabbros, the fractionation asymmetry within individual dykes and the migmatisation of the wall rocks. Pyroxenitic layers result from the fractionation and accumulation of clinopyroxene +/- olivine +/- plagioclase crystals from a mildly alkaline basaltic liquid. They are interpreted as truncated differentiation sequences, from which residual melts were extracted at various stages of their chemical evolution by subsequent dyke intrusions, either next to or within the crystallising unit. Compaction and squeezing of the crystal mush is ascribed to the incoming and inflating magma pulses. The expelled interstitial liquid was likely collected and erupted along with the magma flowing through the newly injected dykes. Clinopyroxene mineral orientation - as evidenced by EBSD and micro X-ray tomography investigations - displays a marked pure-shear component, supporting the interpretation of the role of compaction in the generation of the pyroxenites. Conversely, gabbro sequences underwent minor melt extraction and are believed to represent crystallised coalesced magma batches emplaced at lower rates at the end of eruptive cycles. Clinopyroxene orientations in gabbros record a simple shear component suggesting syn-magmatic deformation parallel to observed NNE-SSW trending shear zones induced by the regional tensional stress field. This emplacement model implies a crystallisation time of 1 to 5 years for individual dykes, consistent with PX1 emplacement over less than 0.5 My. A minimum amount of approximately 150 km(3) of magma is needed to generate the pluton, part of it having been erupted through the Central Volcanic Centre of Fuerteventura. If the regional extensional tectonic regime controls the PX1 feeder-zone initiation and overall geometry, rates and volumes of magma depend on other, source-related factors. High injection rates are likely to induce intrusion growth rates larger than could be accommodated by the regional extension. In this case, dyke intrusion by propagation of a weak tip, combined with the inability of magma to circulate through previously emplaced and crystallised dykes could result in an increase of non-lithostatic pressure on previously emplaced mushy dyke walls; thus generating strong pure-shear compaction within the pluton feeder-zone and interstitial melt expulsion. These compaction-dominated processes are recorded by the cumulitic pyroxenite bands. (C) 2010 Elsevier B.V. All rights reserved.
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OBJECTIVE: To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004. DESIGN: Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding. METHODS: We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations. RESULTS: Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B). CONCLUSIONS: There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.
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Empirical evidence supports the hypothesis that emotional states might contribute to cardiovascular disease and health through multiple pathways. To the extent that the acute cardiovascular response to emotional events plays a role in cardiovascular health and disease, an essential step in order to understand this possible link is to define the hemodynamic response to affective challenges. This was the aim of the present study. We assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output, and total peripheral resistance (TPR) in response to 13 picture series in 18 men and 19 women (mean age 26) in order to investigate their hemodynamic responses associated with activation of the appetitive and defensive motivational systems underlying emotional experience. The hemodynamic parameters were recorded by finger-cuff photoplethysmography with Finometer™ (FMS Finapres Medical Systems, Amsterdam) and electrocardiography with the Lifeshirt system (VivoMetrics Inc., Ventura, California). Participants rated self-perceived pleasantness and arousal for each series. In men, BP and SV, but not TPR, increased with increasing self-rated arousal both for appetitive and defensive activation, whereas in women these relationships were almost absent, especially, for defensive activation. HR decelerated more in response to negative than positive and neutral pictures, and more so in men than women. These findings indicate striking sex differences. In particular, it is suggested that the sympathetic inotropic effect to the heart increases with increasing self-rated arousal strongly in men but only weakly in women. Regardless of sex differences, the modulation of the cardiovascular response to affective pictures along the dimensions of pleasantness and arousal is primarily myocardial, and the pattern of cardiovascular response is consistent with a configuration of cardiac sympathetic-parasympathetic coactivation. One possible implication of the observed sex differences concerns the link between affective states and cardiovascular health and disease. Men have a higher incidence of cardiovascular diseases than premenopausal women, and exaggerated sympathetic reactivity to emotional events is a potential pathophysiological mechanism. These findings extend current knowledge showing that under several acute behavioral challenges men demonstrate stronger cardiovascular reactivity than women.
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Report for the scientific sojourn at the German Aerospace Center (DLR) , Germany, during June and July 2006. The main objective of the two months stay has been to apply the techniques of LEO (Low Earth Orbiters) satellites GPS navigation which DLR currently uses in real time navigation. These techniques comprise the use of a dynamical model which takes into account the precise earth gravity field and models to account for the effects which perturb the LEO’s motion (such as drag forces due to earth’s atmosphere, solar pressure, due to the solar radiation impacting on the spacecraft, luni-solar gravity, due to the perturbation of the gravity field for the sun and moon attraction, and tidal forces, due to the ocean and solid tides). A high parameterized software was produced in the first part of work, which has been used to asses which accuracy could be reached exploring different models and complexities. The objective was to study the accuracy vs complexity, taking into account that LEOs at different heights have different behaviors. In this frame, several LEOs have been selected in a wide range of altitudes, and several approaches with different complexity have been chosen. Complexity is a very important issue, because processors onboard spacecrafts have very limited computing and memory resources, so it is mandatory to keep the algorithms simple enough to let the satellite process it by itself.
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PURPOSE: Investigation of the incidence and distribution of congenital structural cardiac malformations among the offspring of mothers with diabetes type 1 and of the influence of periconceptional glycemic control. METHODS: Multicenter retrospective clinical study, literature review, and meta-analysis. The incidence and pattern of congenital heart disease in the own study population and in the literature on the offspring of type 1 diabetic mothers were compared with the incidence and spectrum of the various cardiovascular defects in the offspring of nondiabetic mothers as registered by EUROCAT Northern Netherlands. Medical records were, in addition, reviewed for HbA(1c) during the 1st trimester. RESULTS: The distribution of congenital heart anomalies in the own diabetic study population was in accordance with the distribution encountered in the literature. This distribution differed considerably from that in the nondiabetic population. Approximately half the cardiovascular defects were conotruncal anomalies. The authors' study demonstrated a remarkable increase in the likelihood of visceral heterotaxia and variants of single ventricle among these patients. As expected, elevated HbA(1c) values during the 1st trimester were associated with offspring fetal cardiovascular defects. CONCLUSION: This study shows an increased likelihood of specific heart anomalies, namely transposition of the great arteries, persistent truncus arteriosus, visceral heterotaxia and single ventricle, among offspring of diabetic mothers. This suggests a profound teratogenic effect at a very early stage in cardiogenesis. The study emphasizes the frequency with which the offspring of diabetes-complicated pregnancies suffer from complex forms of congenital heart disease. Pregnancies with poor 1st-trimester glycemic control are more prone to the presence of fetal heart disease.
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The paper uses a range of primary-source empirical evidence to address the question: ‘why is it to hard to value intangible assets?’ The setting is venture capital investment in high technology companies. While the investors are risk specialists and financial experts, the entrepreneurs are more knowledgeable about product innovation. Thus the context lends itself to analysis within a principal-agent framework, in which information asymmetry may give rise to adverse selection, pre-contract, and moral hazard, post-contract. We examine how the investor might attenuate such problems and attach a value to such high-tech investments in what are often merely intangible assets, through expert due diligence, monitoring and control. Qualitative evidence is used to qualify the more clear cut picture provided by a principal-agent approach to a more mixed picture in which the ‘art and science’ of investment appraisal are utilised by both parties alike
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Standalone levelised cost assessments of electricity supply options miss an important contribution that renewable and non-fossil fuel technologies can make to the electricity portfolio: that of reducing the variability of electricity costs, and their potentially damaging impact upon economic activity. Portfolio theory applications to the electricity generation mix have shown that renewable technologies, their costs being largely uncorrelated with non-renewable technologies, can offer such benefits. We look at the existing Scottish generation mix and examine drivers of changes out to 2020. We assess recent scenarios for the Scottish generation mix in 2020 against mean-variance efficient portfolios of electricity-generating technologies. Each of the scenarios studied implies a portfolio cost of electricity that is between 22% and 38% higher than the portfolio cost of electricity in 2007. These scenarios prove to be “inefficient” in the sense that, for example, lower variance portfolios can be obtained without increasing portfolio costs, typically by expanding the share of renewables. As part of extensive sensitivity analysis, we find that Wave and Tidal technologies can contribute to lower risk electricity portfolios, while not increasing portfolio cost.
Long-term fluctuation of relative afferent pupillary defect in subjects with normal visual function.
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PURPOSE: To determine whether the relative afferent pupillary defect (RAPD) remains constant over time in normal subjects. METHODS: Seventeen normal subjects were tested with infrared pupillography and automated perimetry in four sessions over 3 years. The changes in RAPD and visual field asymmetry between testing sessions were compared. RESULTS: The range of RAPD was 0.0 to 0.3 log unit, and the difference in the mean deviation between the eyes on automated static perimetry was 0 to 3 dB. Eight subjects repeatedly had an RAPD in the same eye. There was no correlation between the RAPD and the visual field asymmetry at the same visit. Changes in the magnitude of the RAPD between any two sessions were typically small (median, 0.08 log unit; 25th percentile, 0.04 log unit; 75th percentile, 0.15 log unit). CONCLUSIONS: Some normal subjects may show a persistent but small RAPD in the absence of detectable pathologic disease. Therefore, an isolated RAPD in the range of 0.3 log unit that is not associated with any other significant historical or clinical finding should probably be considered benign.
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We propose an elementary theory of wars fought by fully rational contenders. Two parties play a Markov game that combines stages of bargaining with stages where one side has the ability to impose surrender on the other. Under uncertainty and incomplete information, in the unique equilibrium of the game, long confrontations occur: war arises when reality disappoints initial (rational) optimism, and it persist longer when both agents are optimists but reality proves both wrong. Bargaining proposals that are rejected initially might eventually be accepted after several periods of confrontation. We provide an explicit computation of the equilibrium, evaluating the probability of war, and its expected losses as a function of i) the costs of confrontation, ii) the asymmetry of the split imposed under surrender, and iii) the strengths of contenders at attack and defense. Changes in these parameters display non-monotonic effects.
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We study the incentive to invest to improve marriage prospects, in a frictionless marriage market with non-transferable utility. Stochastic returns to investment eliminate the multiplicity of equilibria in models with deterministic returns, and a unique equilibrium exists under reasonable conditions. Equilibrium investment is efficient when the sexes are symmetric. However, when there is any asymmetry, including an unbalanced sex ratio, investments are generically excessive. For example, if there is an excess of boys, then there is parental over-investment in boys and under-investment in girls, and total investment will be excessive.