Showing papers by "University of New Hampshire published in 1996"

The Revised Conflict Tactics Scales (CTS2): Development and Preliminary Psychometric Data

Abstract: This article describes a revised Conflict Tactics Scales (the CTS2) to measure psychological and physical attacks on a partner in a marital, cohabiting, or dating relationship; and also use of negotiation. The CTS2 has (a) additional items to enhance content validity and reliability; (b) revised wording to increase clarity and specificity; (c) better differentiation between minor and severe levels of each scale; (d) new scales to measure sexual coercion and physical injury; and (e) a new format to simplify administration and reduce response sets. Reliability ranges from .79 to .95. There is preliminary evidence of construct validity.

Natural and human-induced disturbance of seagrasses

Abstract: Many natural and human-induced events create disturbances in seagrasses throughout the world, but quantifying losses of habitat is only beginning. Over the last decade, 90000 ha of seagrass loss have been documented although the actual area lost is certainly greater. Seagrasses, an assemblage of marine flowering plant species, are valuable structural and functional components of coastal ecosystems and are currently experiencing worldwide decline. This group of plants is known to support a complex trophic food web and a detritus-based food chain, as well as to provide sediment and nutrient filtration, sediment stabilization, and breeding and nursery areas for finfish and shellfish.We define disturbance, natural or human-induced, as any event that measurably alters resources available to seagrasses so that a plant response is induced that results in degradation or loss. Applying this definition, we find a common thread in many seemingly unrelated seagrass investigations. We review reports of seagrass loss from both published and ‘grey’ literature and evaluate the types of disturbances that have caused seagrass decline and disappearance. Almost certainly more seagrass has been lost globally than has been documented or even observed, but the lack of comprehensive monitoring and seagrass. mapping makes an assessment of true loss of this resource impossible to determine.Natural disturbances that are most commonly responsible for seagrass loss include hurricanes, earthquakes, disease, and grazing by herbivores. Human activities most affecting seagrasses are those which alter water quality or clarity: nutrient and sediment loading from runoff and sewage disposal, dredging and filling, pollution, upland development, and certain fishing practices. Seagrasses depend on an adequate degree of water clarity to sustain productivity in their submerged environment. Although natural events have been responsible for both large-scale and local losses of seagrass habitat, our evaluation suggests that human population expansion is now the most serious cause of seagrass habitat loss, and specifically that increasing anthropogenic inputs to the coastal oceans are primarily responsible for the world-wide decline in seagrasses.

Risk factors for youth victimization: Beyond a lifestyles/routine activities theory approach.

Abstract: Past efforts to understand the risks for youth victimization have primarily utilized concepts from lifestyle or routine activity theory, such as the increased exposure and reduced guardianship that are entailed when youth engage in risky or delinquent behavior. In this article, we argue that other personal characteristics put youth at risk, not through any lifestyle or routine activity mechanism, but by making certain youth more "congruent" with the needs, motives, or reactivities of potential offenders. Three specific types of such characteristics are those that increase the potential victim's target vulnerability (e.g., physical weakness or psychological distress), target gratifiability (e.g., female gender for the crime of sexual assault), or target antagonism (e.g., behaviors or ethnic or group identities that may spark hostility or resentment). Using data from a national youth survey, we test variables measuring such aspects of target congruence and show that they make a significant contribution over and above lifestyle variables alone in predicting nonfamily, sexual, and parental assault.

Vertical transport of dissolved organic C and N under long-term N amendments in pine and hardwood forests

Abstract: At the Harvard Forest, Massachusetts, a long-term effort is under way to study responses in ecosystem biogeochemistry to chronic inputs of N in atmospheric deposition in the region. Since 1988, experimental additions of NH4NO3 (0, 5 and 15 g N m-2 yr-) have been made in two forest stands: Pinus resinosa (red pine) and mixed hardwood. In the seventh year of the study, we measured solute concentrations and estimated solute fluxes in throughfall and at two soil depths, beneath the forest floors (Oa) and beneath the B horizons. Beneath the Oa, concentrations and fluxes of dissolved organic C and N (DOC and DON) were higher in the coniferous stand than in the hardwood stand. The mineral soil exerted a strong homogenizing effect on concentrations beneath the B horizons. In reference plots (no N additions), DON composed 56% (pine) and 67% (hardwood) of the total dissolved nitrogen (TDN) transported downward from the forest floor to the mineral soil, and 98% of the TDN exported from the solums. Under N amendments, fluxes of DON from the forest floor correlated positively with rates of N addition, but fluxes of inorganic N from the Oa exceeded those of DON. Export of DON from the solums appeared unaffected by 7 years of N amendments, but as in the Oa, DON composed smaller fractions of TDN exports under N amendments. DOC fluxes were not strongly related to N amendment rates, but ratios of DOC:DON often decreased. The hardwood forest floor exhibited a much stronger sink for inorganic N than did the pine forest floor, making the inputs of dissolved N to mineral soil much greater in the pine stand. Under the high-N treatment, exports of inorganic N from the solum of the pine stand were increased >500-fold over reference (5.2 vs. 0.01 g N m-2 yr-V), consistent with other manifestations of nitrogen saturation. Exports of N from the solum in the pine forest decreased in the order NO3-N > NH4-N > DON, with exports of inorganic N 14-fold higher than exports of DON. In the hardwood forest, in contrast, increased sinks for inorganic N under N amendments resulted in exports of inorganic N that remained lower than DON exports in N-amended plots as well as the reference plot.

Quantifying Eelgrass Habitat Loss in Relation to Housing Development and Nitrogen Loading in Waquoit Bay, Massachusetts

Abstract: Change analysis of eelgrass distribution in Waquoit Bay demonstrated a rapid decline of eelgrass habitat between 1987 and 1992. Aerial photography and ground-truth assessments of eelgrass distribution in the Waquoit Bay National Estuarine Research Reserve documented progressive loss in eelgrass acreage and fragmentation of eelgrass beds that we relate to the degree of housing development and associated nitrogen loading, largely via groundwater, within various sub-basins of the estuary. The sub-basins with greater housing density and higher nitrogen loading rates showed more rapid rates of eelgrass decline. In eelgrass mesocosm studies at the Jackson Estuarine Laboratory, excessive nitro- gen loading stimulated proliferation of algal competitors (epiphytes, macroalgae, and phytoplankton) that shade and thereby stress eelgrass. We saw domination by each of these three algal competitors in our field observations of eelgrass decline in Waquoit Bay. Our study is the first to relate housing development and nitrogen loading rates to eelgrass habitat loss. These results for the Waquoit Bay watershed provide supporting evidence for management to limit development that results in groundwater nitrogen loading and to initiate remedial action in order to reverse trends in eelgrass habitat loss.

Patriarchal ideology and wife-assault: A meta-analytic review

Abstract: Using the framework of patriarchal theory, the present meta-analytic review examined the predicted relation between wife assault and the maintenance of a patriarchal ideology. This relationship was evaluated using three measures of patriarchal ideology: (1) attitudes toward violence, (2) gender attitudes, and (3) gender schemas. Overall, assaultive husbands reported more positive attitudes toward marital violence and lower scores on masculine and feminine gender schema scales than nonassaultive husbands. Methodological factors accounted for the significant heterogeneity among the gender attitude effect estimates for men. A nonsignificant average effect in the males' gender attitude emerged in studies which used husbands' self-report data and case-control comparison groups. In contrast to men, assaulted wives held more feminine gender schema and tended to exhibit more liberal gender attitudes than nonassaulted wives across studies. These meta-analytic findings offer limited support for the ideological component of the patriarchal theory of wife assault and are discussed with respect to their theoretical and methodological implications.

Extrapolating leaf CO2 exchange to the canopy: a generalized model of forest photosynthesis compared with measurements by eddy correlation.

Abstract: Over the last 4 years, two data sets have emerged which allow increased accuracy and resolution in the definition and validation of a photosynthesis model for whole forest canopies. The first is a greatly expanded set of data on the nitrogen-photosynthesis relationship for temperate and tropical woody species. The second is a unique set of long-term (4 year) daily carbon balance measurements at the Harvard Forest, Petersham, Massachusetts, collected by the eddy-correlation technique. A model (PhET-Day) is presented which is derived directly from, and validated against, these data sets. The PnET-Day model uses foliar nitrogen concentration to calculate maximum instantaneous rates of gross and net photosynthesis which are then reduced for suboptimal temperature, photosynthetically active radiation (PAR), and vapor pressure deficit (VPD). Predicted daily gross photosynthesis is closely related to gross carbon exchange at the Harvard Forest as determined by eddy-correlation measurements. Predictions made by the full canopy model were significantly better than those produced by a multiple linear regression model. Sensitivity analyses for this model for a deciduous broad-leaved forest showed results to be much more sensitive to parameters related to maximum leaf-level photosynthetic rate (A max) than to those related to light, temperature, VPD or total foliar mass. Aggregation analyses suggest that using monthly mean climatic data to drive the canopy model will give results similar to those achieved by averaging daily eddy correlation measurements of gross carbon exchange (GCE).

Eustatic Curve for the Middle Jurassic--Cretaceous Based on Russian Platform and Siberian Stratigraphy: Zonal Resolution

Abstract: We have used the stratigraphy of the central part of the Russian platform and surrounding regions to construct a calibrated eustatic curve for the Bajocian through the Santonian. The study area is centrally located in the large Eurasian continental craton, and was covered by shallow seas during much of the Jurassic and Cretaceous. The geographic setting was a very low-gradient ramp that was repeatedly flooded and exposed. Analysis of stratal geometry of the region suggests tectonic stability throughout most of Mesozoic marine deposition. The paleogeography of the region led to extremely low rates of sediment influx. As a result, accommodation potential was limited and is interpreted to have been determined primarily by eustatic variations. The central part of the Russian latform thus provides a useful frame of reference for the quantification of eustatic variations throughout the Jurassic and Cretaceous. The biostratigraphy of the Russian platform provides the basis for reliably determining age and eustatic events. The Mesozoic section of the central part of the Russian platform is characterized by numerous hiatuses. In this study, we filled the sediment gaps left by unconformities in the central part of the Russian platform with data from stratigraphic information from the more continuous stratigraphy of the neighboring subsiding regions, such as northern Siberia. Although these sections reflect subsidence, the time scale of variations in subsidence rate is probably long relative to the duration of the stratigraphic gaps to be filled, so the subsidence rate can be calculated and filtered from the stratigraphic data. We thus have compiled a more complete eustatic curve than would be p ssible on the basis of Russian platform stratigraphy alone. Relative sea level curves were generated by backstripping stratigraphic data from well and outcrop sections distributed throughout the central part of the Russian platform. For determining paleowater depth, we developed a model specifically designed for this region based on paleoecology, sedimentology, geochemistry, and paleogeography. The curve describes a series of high-frequency eustatic events superimposed on longer term trends. Many of the events identified from our study can be correlated to those found by Haq et al. (1988) and other sea level studies from other parts of the world, but there are significant differences in the relative magnitudes of events. Because the eustatic curve resulting from this study is based on a stable reference frame, the curve can be used in sedimentary basin modeling and as a tool for quantifying subsidence history from the stratigraphy of passive margins, basins, and other active regions.

An empirical analysis of the product-process matrix

Abstract: Process choice, a major part of operations strategy, is a key decision that links operations to business strategy. Hayes and Wheelwright, among others, argue that the emphasis given to product customization and other competitive priorities should agree with process choice. Our empirical study investigates whether firms actually link their process choice to product customization and other competitive priorities as hypothesized, and whether compatible decision patterns lead to better performance. Analysis of data collected from managers at 144 U.S. manufacturing plants shows a strong correlation between process choice, product customization, and competitive priorities. Process choice is highly related with the degree of product customization, and also with the emphasis placed on the quality and cost competitive priorities. Job shops and batch shops tend to have more product customization, higher costs, and higher quality. Some continuous flow shops use part commonality and flexible automation to achieve more customization than would otherwise be expected. Without these initiatives, customization in continuous flow shops results in weak performance.

Phenotypic plasticity in an intertidal snail: the role of a common crab predator.

Abstract: Prey species may reduce their risk of predation in many ways (for reviews, see Edmunds 1974; Vermeij 1978, 1987). Although avoidance behaviors and chemical defenses can act as deterrents to predation in marine environments, morphological changes have received the greatest emphasis. For example, spines in a marine bryozoan (Harvell 1984), barnacle shape (Lively 1986a), and numerous gastropod shell traits (Vermeij 1978) are known to deter predation. In intertidal environments, predation by invertebrate predators often parallels gradients in wave exposure and is often most important on shores protected from direct wave energy (Menge 1978). Likewise, variation in the shell thickness of intertidal gastropods also tends to parallel gradients in wave exposure and predation intensity. Thick-shelled morphs are typically found on protected shores where crab predators are more abundant, whereas thin-shelled morphs are found on wave-exposed shores (Kitching et al. 1966; Kitching and Lockwood 1974; Reimchen 1982; Palmer 1985a, 1990). Extreme turbulence probably inhibits crab foraging on waveexposed shores (Kitching et al. 1966; Crothers 1968; Menge 1978). Shell thickness of intertidal gastropods varies among intertidal shores, in part because of differential predation by crabs (Kitching et al. 1966; Kitching and Lockwood 1974; Vermeij 1978, 1987; Seeley 1986). Although natural selection by crabs has been suggested to promote the evolution of thicker-shelled snails (Seeley 1986), predator-induced phenotypic plasticity may also influence shell thickness (Appleton and Palmer 1988; Palmer 1990). Predator-induced morphological defenses are a unique example of phenotypic plasticity in which the predator or a cue associated with the predator (often chemical in nature) induces the formation of structures in the prey that deter predation. This phenomenon is common in aquatic rotifer and zooplankton assemblages (for a review, see Dodson 1989). Most examples of predator-induced defenses involve plants (Baldwin and Schultz 1983; Haukioja and Neuvonen 1985; Rhoades 1985) or clonal (e.g., the cladoceran zooplankton examples cited in Dodson 1989) and colonial organisms (Harvell 1984, 1986). Cases of predator-induced defenses in solitary organisms appear to be rare. Curiously, cases involving solitary organisms, with the exception of Bronmark and Miner (1992), have been found in intertidal environments (Lively

Effects of ultraviolet radiation on corals and other coral reef organisms

Abstract: The discovery of the importance of solar ultraviolet radiation (UVR) as a factor affecting the biology of coral reefs dates only to about 1980. Interest has heightened during the past five years owing to the demonstration of loss of stratospheric ozone through human activities. We have only begun to document gross, qualitative effects of UVR on coral reef organisms, usually in experiments comparing the biological response to the presence or absence of UVR through the use of UV-cutoff filters, or to varying levels of UVR in transplantation studies. Most such studies have not distinguished between the effects of UVA (320–400 nm) and those of UVB (290–320 nm), although in the context of global change involving stratospheric ozone loss, it is the latter wavelengths that are relevant. To date we have been addressing physiological and ecological questions, not yet attempting to evaluate quantitatively the impact of forecast increases in solar UVB penetration. Interacting and synergistic effects of UVR with increased temperature, pollutants, sedimentation, visible light, etc. have scarcely been studied but will be essential to understanding and predicting the fate of coral reefs under conditions of global change. Here we comprehensively review the effects of UVR on corals and other reef macroorganisms, mindful that although much is known of proximal effects, little of this knowledge is directly useful in making long-term predictions regarding the health of coral reefs. We conclude that even small anthropogenic increases in UVB levels will have sublethal physiological manifestations in corals and other reef organisms, but that this will have relatively small impact on the distribution of reef corals and coral reefs, perhaps affecting their minimum depths of occurrence.

Risk of physical abuse to children of spouse abusing parents

Abstract: Cette etude avait pour but de calculer les probabilites, basees sur le sexe, que le(la) conjoint(e) qui est violent(e) envers l'autre, agressera aussi leur enfant. L'etude se basait sur un echantillon represetatif comprenant 3.363 parents americains qui avaient fait partie du sondage national de 1985 sur la violence familiale. L'etude demontre que la violence entre conjoints est un element important pour predire s'il y aura violence faite aux enfants. Plus il y a de violence entre conjoint et conjointe, plus grandes sont les chances que l'un ou l'autre agressera l'enfant. La correlation est plus forte pour les hommes que pour les femmes. La probabilite que le conjoint agressera son enfant passe de 5 p.c. a 100 p.c. selon qu'il a agresse sa femme une fois ou 50 fois ou plus. Pour la conjointe, les probabilites passent de 5 p.c. a 30 p.c. L'etude discute des consequences en rapport au divorce.

Calcium inputs and transport in a base-poor forest ecosystem as interpreted by Sr isotopes

Abstract: Depletion of Ca in forests and its effects on forest health are poorly quantified. Depletion has been difficult to document due to limitations in determining rates at which Ca becomes available for ecosystem processes through weathering, and difficulty in determining changes in ecosystem storage. We coupled a detailed analysis of Sr isotopic composition with a mass balance at Cone Pond Watershed, New Hampshire, in order to further constrain estimates of these processes. Strontium acted as an analog for Ca in most processes except translocation of nutrients within forest vegetation. Variability in mineralogic and Sr isotopic composition of bedrock and soils complicated assessment of the 87Sr/86Sr ratio released to solution by weathering reactions. By conducting a mass balance on atmospherically derived Ca, it is possible to distinguish Ca weathering losses from Ca leached from ecosystem pools. The calcium weathering rate estimated by this method was less than half of that determined by mass balance assuming steady state conditions.

Strategy and control in supplier–distributor relationships: an agency perspective

Abstract: This paper examines the influence of competitive strategy on the relationship between suppliers and their distribution networks. Drawing on agency theory, hypotheses are developed specifying the appropriate match between manufacturer strategies and systems of control within distribution channels. Cluster analysis is used to show distinct differences in channel management and structure for the three generic strategies of cost leadership, differentiation and focus. Results suggest that variation in control relationships may be explained by the demands posed by manufacturers' competitive strategies. This study therefore extends the applicability of Porter's typology to the specific structure of distribution channels and shows that agency theory can provide insights into the economic basis of interorganizational relationships.

A review of deep hydrodesulfurization catalysis

Abstract: Introduction The increasing importance of hydrodesulfurization (HDS) in petroleum processing in order to produce clean-burning fuels has led to a surge of research on the chemistry and engineering of HDS. Most of the earlier works are focused on catalyst characterization by physical methods; on low-pressure reaction studies of compounds like thiophene having relatively high reactivities; on process development; or on CoMo, NiMo, or NiW catalysts supported on alumina, often doped by fluorine or phosphorus. Almost all the reviews have concentrated on alumina-supported CoMo, NiMo, and NiW sulfide catalysts for hydrotreating. Even reviews that are not limited to the above catalytic systems essentially deal with studies of simple compounds like thiophene.

Unmasking a modulated chaotic communications scheme

Abstract: This paper will address the problem of unmasking a new chaotic communication scheme using synchronizing circuits, where the Lorenz system is modulated by the message and the x-coordinate of the modulated system is added to the message and transmitted to the receiver. The receiver is driven into perfect synchrony with the transmitter even in the presence of the message, and since the message becomes part of the dynamics it provides very little distortion to the phase space of the dynamical system. However, this paper will demonstrate that it is still possible to extract a sinusoidal message from the transmitted signal. It will also be shown that it is possible to extract the sinusoidal signal solely from the x-coordinate, without secondarily adding back the message sinusoid before transmission. The message extraction is also shown to work for simple frequency-modulated and phase-modulated message signals. The modulated communication scheme does effectively nullify a multi-step unmasking technique which had been somewhat successful when applied to chaotic communication schemes which employed additive message signals.

Configuration as Composite Constraint Satisfaction

Abstract: Selecting and arranging parts is the core of a configuration task. The validity of a configuration is defined in terms of constraints. Highly declarative, domain independent and simple to use, the constraint 6atisfaetion problem (CSP) paradigm offers an adequate framework for this task. However, the basic paradigm is not powedul enough to capture or to take advantage of essential aspects of configuration, such as the unknown a priori number of constituent parts of a system or the inherent internal structure of these parts. Although notable effort has been spent on extending the basic paradigm to accommodate these issues, we still lack a comprehensive formalism for configuration. This paper presents the main ideas behind a general constraint-based model of configuration tasks represented as a new class of nonstandard constraint satisfaction problems, called composite CSP. Composite CSP unifies several CSP extensions, providing a more comprehensive and efficient basis for formulating and solving configuration problems.

Potential atmospheric impact of the Toba Mega‐Eruption ∼71,000 years ago

Abstract: An {approx}6 year-long period of volcanic sulfate recorded in the GISP2 ice core about 71,000 {+-} 5000 years ago may provide detailed information on the atmospheric and climate impact in the Toba mega-eruption. Deposition of these aerosols occur beginning of an {approx}1000-year long stadial event, but not immediately before the longer glacial period beginning {approx}67,500 years ago. Total stratospheric loading estimates over this {approx}6 year period range from 2200 to 4400 Mt of H{sub 2}SO{sub 4} aerosols. The range in values is given to compensate for uncertainties in aerosol transport. Magnitude and longevity of the atmospheric loading may have led directly to enhanced cooling during the initial two centuries of this {approx}1000-year cooling event. 25 refs., 2 fig., 1 tab.

Seasonal and interannual patterns of sediment- water nutrient and oxygen fluxes in Mobile Bay, Alabama (USA): regulating factors and ecological significance

Abstract: Sedlment oxygen and nutrlent fluxes were measured monthly for 2 yr in Moblle Bay, Alabama, USA. Rates of sedment oxygen consumphon (0 1 to 125 go2 m-2 d-I), ammonium flux (-22 to 181 pmol m-2 h-I), mtrate flux (-14 to 67 pmol m-2 h-I), phosphate flux (-2 to 20 4 pmol m h-l), and dissolved sficate flux (-15 to 342 pmol m-2 h-l) were moderate to high compared to values for other estuanes A step-wlse regression analysls revealed that dissolved oxygen concentration and tempera- ture in bottom-waters explained much of the variance in fluxes This 1s presumably because of their influence on rates of microbial and physico-chemcal processes Organic matter avdabihty was not found to be an important factor m regulatmg temporal (month to month) variabihty of fluxes, possibly because frequent resuspension of the sediments in thls shallow system rendered indices of sedment organic matter nearly constant with tme However, warm season-averaged sedment nutrlent releases were correlated with sedment chlorophyll a. This relationship m Moblle Bay 1s m strong agreement urlth slrmlar relabonshps found in other estuanne systems, and suggests that the avallabihty of lablle orgamc matter ultmately regulates the maxmum rate of nutnent release by the sedunents Annually averaged sedlment fluxes supphed 36 % of the nitrogen (N) and 25 % of the phosphorus (P) reqmred by phytoplankton m Mobile Bay. Whlle ths is not parhcularly hgh compared to other estuaries, monthly estimates show that the sedments can supply from 0 to 94 % of the N, and 0 to 83 % of the P reqwed by phytoplankton In addition, flux ratios show that N and P are released from sediments at N P ratios that rapidly sultch from above (maximum 98) to below (mmmum 1 2) that reqmred for phytoplankton growth. Ths pattern 1s different from cooler temperate systems, where such switching is seasonally based.

Observations of the lunar plasma wake from the WIND spacecraft on December 27, 1994

Abstract: On December 27, 1994, the WIND spacecraft crossed the lunar wake at a distance of 6.5 lunar radii ( RL ) behind the moon. The observations made were the first employing modem instruments and a high data rate. The SWE plasma instrument on WIND observed new aspects of the interaction between the solar wind and unmagnetized dielectric bodies. The plasma density decreased exponentially from the periphery of the wake towards its center as predicted by simple theory. Behind the moon two distinct cold ion beams were observed refilling the lunar cavity. The ions were accelerated along the direction of the magnetic field by an electric field of the order 2 × 10−4 volts/m. The region of plasma depletion was observed to extend beyond the light shadow, consistent with a rarefaction wave moving out from the wake into the undisturbed solar wind.