Search

BackgroundThis is the second of a two-part series exploring father's inclusion in the perinatal years. The first paper was published in volume 29, issue 4 of the British Journal of Midwifery. This paper explores the results of the study and discussion in relation to previous literature and to professional practice. Positive father involvement during the perinatal period has important implications for families. However, previous research suggests that fathers experience marginalisation, while staff report a lack of training and time for engaging fathers.AimsThis study explored fathers' and perinatal professionals' experiences of fathers' involvement during the perinatal period, and ideas for paternal support.MethodA Delphi method was employed. Thematic analysis from focus groups informed an online survey which was completed by 24 fathers and 22 professionals. A third-round survey finalised group consensus.ResultsBoth groups agreed on the importance of fathers. Participants suggested improvement ideas, such as supporting fathers with psychological change. Groups disagreed on some ideas, such as fathers receiving a session alone to discuss concerns.DiscussionThe findings support the inclusion of fathers in perinatal services and a focus on the whole family system. Limitations of this study include low participant diversity and possible selection bias. Implications for further research are discussed.

BackgroundThis is the first of a two-part series exploring father's inclusion in the perinatal years. Part 2 will explore the results of the study and discuss in relation to previous literature and to professional practice. Positive father involvement during the perinatal period has important implications for families. However, previous research suggests that fathers experience marginalisation, while staff report a lack of training and time for engaging fathers.AimsThis study explored fathers' and perinatal professionals' experiences of fathers' involvement during the perinatal period, and ideas for paternal support.MethodA Delphi method was employed. Thematic analysis from focus groups informed an online survey which was completed by 24 fathers and 22 professionals. A third-round survey finalised group consensus.ResultsBoth groups agreed on the importance of fathers. Participants suggested improvement ideas, such as supporting fathers with psychological change. Groups disagreed on some ideas, such as fathers receiving a session alone to discuss concerns.DiscussionThe findings support the inclusion of fathers in perinatal services, and a focus on the whole family system. Limitations of this study include low participant diversity and possible selection bias. Implications for further research are discussed.

Dissociative seizures are paroxysmal events resembling epilepsy or syncope with characteristic features that allow them to be distinguished from other medical conditions. We aimed to compare the effectiveness of cognitive behavioural therapy (CBT) plus standardised medical care with standardised medical care alone for the reduction of dissociative seizure frequency.

Four additives (a sodium polyphosphate, microsilica, titania and zirconia) were tested in a magnesia alumina castable to investigate their influence on the spinel formation at high temperatures. The impact of the additives is studied with respect to both the amount of spinel formed in the burned castable and the microstructure established by the spinalization.

Alpha-1 antitrypsin deficiency (AATD) is a genetic condition with chronic obstructive pulmonary disease (COPD)-like symptoms that typically present later in life. We compared clinical characteristics between individuals diagnosed with COPD and AATD and those with COPD alone.

The purpose of this paper is to review skin cancer screening guidelines from major public health/medical organizations. No consensus exists on whether or not screening to prevent skin cancer is warranted. The best evidence of screening efficacy should come from population-based randomized trials, but is unlikely to exist due to feasibility constraints. Consequently, consensus should be built from observational/non-randomized designs, such as the SCREEN study in Germany. Current guidelines often focus on melanoma alone, while potential benefits of screening for non-melanoma skin cancers (NMSC) are largely overlooked. There may be less room for doubt regarding the value of screening, if both diseases were considered. Further, targeted approaches, i.e., screening only in high-risk populations, remain poorly defined and untested. Continuing to state that there is insufficient evidence to recommend screening leads to confusion about whether or not to screen and is unlikely to result in substantial changes to the morbidity of NMSC and significant mortality from melanoma.

Non-melanoma skin cancer outnumbers all other cancers combined by three to four-fold while melanoma is the fifth most common cancer overall, and the deadliest form of skin cancer. Despite treatment advancements in the past several decades, incidence continues to rise. Phytochemicals and other naturally occurring substances may provide sustainable chemopreventive solutions. The purpose of this study is to review the key findings from the literature and report on the level of evidence based on study design. A comprehensive PubMed search was completed from 1984 to present using keywords “skin cancer chemoprevention” alone and with “phytochemicals,” “alternative,” “essential oils,” and “vitamins.” This search demonstrated that the literature strongly endorses the role of naturally occurring substances in the context of skin cancer chemoprevention, however the literature is predominantly comprised of data based on in vitro and animal based models. Prior to acceptance into mainstream practice, high quality prospective studies to evaluate the role of naturally occurring compounds in the context of skin cancer chemoprevention are indicated.

We review the existing scientific literature regarding skin cancer in Hispanics to aid in formulating a research agenda for prevention targeted to this at-risk population. Hispanics are a diverse population with a rising incidence of both melanoma and non-melanoma skin cancer. Compared with non-Hispanic whites, Hispanics have poorer disease outcomes and higher rates of acral lentiginous melanoma, an aggressive subtype. Hispanics practice suboptimal sun protection and skin surveillance behaviors and experience rates of sunburn comparable with non-Hispanic whites. Despite these risk behaviors, little skin cancer education and prevention has been targeted to this population. Further research is warranted to understand the interplay of biological, psychosocial, cultural, and health care factors influencing skin cancer prevention behaviors and outcomes in Hispanics. We recommend future investigation into the histological, sociocultural, and health care differences and disparities among Hispanics and within subpopulations to develop tailored, culturally informed prevention strategies.

Great technological advances have been made in Precision Agriculture (PA) in the past decade, yet adoption of PA in intensive grassland areas in North West Europe is low. This is despite the fact that in these areas the market structures are suitable and there are highly developed agricultural and food industries offering great potential for the application of new technology. Specific inefficiencies in plant nutrient management in soil exist, which are not only limiting grass yields but are also causing environmental deterioration. Soil nutrient management efficiency could be greatly improved using PA techniques, but the complexity of grassland systems, coupled with a lack of calibration of sensors specific to grassland, together with local barriers, appear to be the reasons why PA adoption is poor in these areas. This paper reviews new and existing technology including soil and crop sensors, navigation devices, remote sensing and unmanned aerial vehicles. The suitability and readiness of these technologies for adoption in grassland areas is discussed, along with data interpretation issues, future perspectives and research opportunities.

ObjectiveTo determine the prevalence of newly diagnosed hepatitis C virus (HCV) and associated risk behaviours among men who have sex with men (MSM) in Manchester.MethodA survey among MSM attending four genitourinary medicine clinics in Manchester was carried out over 9 months in 2013. Participants were asked about recent sexual behaviour, recreational drug use and HIV status. All men were offered an HCV test.ResultsOverall, 2030 MSM completed a questionnaire and accepted an HCV test. Of whom, 0.9% (18) were newly diagnosed with HCV, including 1.8% (13/735) of HIV-positive MSM, 0.7% (3/440) of MSM of unknown HIV status and 0.2% (2/855) of HIV-negative MSM. HCV positivity was significantly associated with HIV status (p<0.001). When compared with HIV-negative MSM, HIV-positive MSM had higher rates of sharing snorting drug equipment, injecting drugs/‘slamming’ and using recreational drugs (all p<0.05) but lower rates of five or more sexual partners and insertive unprotected anal intercourse (p<0.05). MSM newly diagnosed with HCV had significantly higher prevalence of unprotected sex, sex with someone HCV positive, fisting, group sex, ever injecting drugs/‘slamming’ and recreational drug use (p<0.002).ConclusionsIn this survey, HIV-positive MSM had significantly different drug use behaviour which may explain the higher HCV burden. However, HCV was also associated with HIV-negative MSM engaging in high-risk sexual practices. All MSM attending sexual health clinics must have a risk assessment and HCV screening should be offered based on the risk. Further studies are warranted to explore the interplay between HCV and HIV risk associated with drug use versus sexual practices.

The phosphorus index (PI) is a field-scale assessment tool developed to identify fields most vulnerable to phosphorus (P) loss. The USDA Natural Resource Conservation Service (NRCS) recently revised its 590 Nutrient Management Standard and Title 190 National Instruction requiring that all NRCS-approved PI tools meet certain criteria. A recent study evaluating the Kentucky PI showed that it did not meet several of the criteria established by NRCS. This paper describes the development and evaluation of a revised PI for Kentucky in response to the revised 590 Standard. Important revisions to the Kentucky PI include (1) use of a component formulation, (2) incorporation of erosion and P application rates, (3) use of continuous variables, and (4) use of empirically based weighting factors. The revised Kentucky PI was evaluated against measured P loss data reported in the literature. Output from the revised PI was well correlated (Spearman's ρ = 0.86; p< 0.001) with the measured P loss data. Results also indicated that the revised Kentucky PI correctly assigned the appropriate risk category to the majority of fields with P loss values below or above our predefined cutoff values for low and high risk fields. On the other hand, the revised PI only correctly categorized 43% of the fields deemed to be at moderate risk. To assess whether the revised PI provided improved estimates of P loss risk, output from both the original and revised Kentucky PIs was compared against a P loss data set collected in the southern United States. Both the original (after modifications to soil test P [STP] and runoff ratings) and revised Kentucky PIs were significantly correlated with the measured P loss data, though the revised PI (Spearman's ρ = 0.92; p< 0.001) was more strongly correlated than the original Kentucky PI (Spearman's ρ = 0.42; p= 0.03). The original and revised Kentucky PIs were also compared by calculating P loss risk for 46 fields in Kentucky using data recently collected for developing comprehensive nutrient management plans. The approach adopted in this study to revise the Kentucky PI should offer guidance to other states currently in the process of revising their PI.

AbstractConservation tillage is an agricultural strategy to mitigate atmospheric greenhouse gas (GHG) emissions. In eastern Washington, we evaluated the long-term effects of conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) on soil organic carbon (SOC) storage and nitrous oxide (N2O) emissions at three dryland and one irrigated location using the cropping systems simulation model CropSyst. Conversion of CT to NT produced the largest relative increase in SOC storage (ΔSOC, average yearly change relative to CT) in the top 30 cm (11.8 in) of soil where ΔSOC ranged from 0.29 to 0.53 Mg CO2e ha−1y−1(CO2e is carbon dioxide [CO2] equivalent of SOC; 0.13 to 0.24 tn CO2e ac−1yr−1). The ΔSOC were less with lower annual precipitation, greater fallow frequency, and when changing from CT to RT. Overall, ΔSOC decreased from the first to the third decade after conversion from CT to NT or RT. Simulations of ΔSOC for the conversion of CT to NT based on a 0 to 15 cm (0 to 5.9 in) soil depth were greater than the ΔSOC based on a 0 to 30 cm depth, primarily due to differences among tillage regimes in the depth-distribution of carbon (C) inputs and the resultant SOC distribution with depth. Soil erosion rates under CT in the study region are high, posing deleterious effects on soil quality, productivity, and aquatic systems. However, an analysis that includes deposition, burial, and sedimentation on terrestrial and aquatic systems of eroded SOC indicates that the substantial erosion reduction obtained with RT and NT may result only in minor additional SOC oxidation as compared to CT. Simulated N2O emissions, expressed as CO2equivalent, were not very different under CT, RT, and NT. However, N2O emissions were sufficiently high to offset gains in SOC from the conversion of CT to RT or NT. Thus, reducing tillage intensity can result in net C storage, but mitigation of GHG is limited unless it is coupled with nitrogen (N) fertilizer management to also reduce N2O emission.

Background: There is evidence that the impact of environmental factors on insulin sensitivity is modified by the presence of family history of diabetes. Aim: To compare the association between the erythrocyte phospholipid fatty acid composition (a biomarker of dietary fatty acids) and insulin sensitivity in daughters of Type 2 diabetic patients with the corresponding association in women without family history of diabetes. Material/subjects and methods: Eighteen offspring of Type 2 diabetic patients [age 30±6.5 yr; body mass index (BMI) 22.2±2.5 kg/m2; body fat 31.8±5.1%] and 18 matched women (age 30.1±6.8 yr; BMI 22.2±1.8 kg/m2; body fat 32.2±6.0%) participated in the study. Results: Insulin Sensitivity Index (ISI)-Matsuda tended to be lower (p=0.06) in the Offspring than the control group. Weight proportions of erythrocyte phospholipid saturated (SFA), polyunsaturated (PUFA), and monounsaturated fatty acids (MUFA) were similar between the two groups. In the offspring, erythrocyte total SFA were negatively correlated with ISI-Matsuda [r=−0.47, p<0.05), ISI(gly)-Belfiore (r=−0.52, p<0.05) and ISI(ffa)-Belfiore (r=−0.53, p<0.05)], whereas total PUFA were positively correlated with insulin sensitivity [ISI-Matsuda, r=0.46, p<0.05; ISI(gly)-Belfiore, r=0.53, p<0.05; ISI(ffa)-Belfiore, r=0.54, p<0.05]. No significant correlations were observed in the control group. Conclusions: The associations between erythrocyte fatty acid composition and insulin sensitivity are distinct between daughters of Type 2 diabetic patients and women without family history of diabetes.

Greenhouse gas (CO2, CH4, and N2O) emissions were measured in a field experiment evaluating preplant swine effluent application methods for no‐till corn (Zea maysL.) grain production. The treatments included a control, an inorganic fertilizer treatment receiving 179 kg N ha−1as urea–NH4NO3(UAN), and three effluent application methods that received a target rate of 200 kg N ha−1The effluent treatments included surface application, direct injection, and application in combination with soil aeration. Gas emission measurements were initiated after application and collected throughout the 2007 and 2008 growing seasons using a vented chamber technique. There were no significant differences in CO2losses, which averaged 738 and 718 g CO2m−2in 2007 and 2008, respectively. Placement of effluent below the soil surface by injection or aeration resulted in elevated CH4emissions compared with the control. Injection emitted significantly more CH4than surface applications, with emissions of 0.26 and 0.80 g CH4m−2from the injection treatments in 2007 and 2008, respectively. In 2007, N2O emissions were similar for the UAN, surface effluent, and aeration effluent treatments, emitting an average of 0.72 g N2O m−2In contrast, the injection treatment emitted 0.47 g N2O m−2In 2008, this trend was reversed, with the injection treatment emitting 0.82 g N2O m−2and the remaining N source treatments emitting an average of 0.36 g N2O m−2These differences between years probably resulted from differences in rainfall distribution. These results demonstrate that climatic conditions and application method need consideration when evaluating the impact of liquid manure management on greenhouse gas emissions.

Abstract: This preliminary study aims to investigate a M w 6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber, style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures.

Intensive agriculture and increased N fertilizer use have contributed to elevated emissions of the greenhouse gases carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). In this study, the exchange of CO2, N2O, and CH4between a Quincy fine sand (mixed, mesic Xeric Torripsamments) soil and atmosphere was measured in a sweet corn (Zea maysL.)–sweet corn–potato (Solanum tuberosumL.) rotation during the 2005 and 2006 growing seasons under irrigation in eastern Washington. Gas samples were collected using static chambers installed in the second‐year sweet corn and potato plots under conventional tillage or reduced tillage. Total emissions of CO2–C from sweet corn integrated over the season were 2071 and 1684 kg CO2–C ha−1for the 2005 and 2006 growing seasons, respectively. For the same period, CO2emissions from potato plots were 1571 and 1256 kg of CO2–C ha−1Cumulative CO2fluxes from sweet corn and potato fields were 17 and 13 times higher, respectively, than adjacent non‐irrigated, native shrub steppe vegetation (NV). Nitrous oxide losses accounted for 0.5% (0.55 kg N ha−1) of the applied fertilizer (112 kg N ha−1) in corn and 0.3% (0.59 kg N ha−1) of the 224 kg N ha−1applied fertilizer. Sweet corn and potato plots, on average, absorbed 1.7 g CH4–C ha−1d−1and 2.3 g CH4–C ha−1d−1, respectively. The global warming potential contributions from NV, corn, and potato fields were 459, 7843, and 6028 kg CO2–equivalents ha−1, respectively, for the 2005 growing season and were 14% lower in 2006.

We have prepared and screened a library of novel functionalized polymers for development of nanoparticle drug delivery systems. The polymer backbone consisting of two ester-linked, nontoxic, biological monomers, glycerol and adipic acid, was prepared using a hydrolytic enzyme. The specificity of the chosen enzyme yields a linear polymer with one free pendant hydroxyl group per repeat unit, which can be further functionalized. This protocol gives control over the backbone polymer molecular weight, together with the ability to incorporate various amounts of different fatty acyl substituents. These functionalized polymers are able to self-assemble into well-defined small particles of high homogeneity with a very low toxicity. They are able to incorporate a water soluble drug, dexamethasone phosphate, with a high efficiency and drug loading which varies with the polymer specification. The above characteristics strongly suggest that these polymers could be developed into useful nanoparticulate drug delivery systems.

Trauma is the leading non-obstetric cause of maternal death. Optimal management of the pregnant trauma patient requires a multidisciplinary approach. The anaesthetist and critical care physician play a pivotal role in the entire continuum of fetomaternal care, from initial assessment, resuscitation and intraoperative management, to postoperative care that often involves critical care support and patient transfer. Primary goals are aggressive resuscitation of the mother and maintenance of uteroplacental perfusion and fetal oxygenation by the avoidance of hypoxia, hypotension, hypocapnia, acidosis and hypothermia. Recognizing and understanding the mechanisms of injury, the factors that may predict fetal outcome, and the pathophysiological changes that can result from trauma, will allow early identification and treatment of fetomaternal injury. This in turn should improve morbidity and mortality. A framework for the acute care of the pregnant trauma patient is presented.

The adsorption behavior of viologen α,ω-dithiols (viologen dithiols) on gold has been investigated. At short exposures, a low-coverage phase consisting of flat-lying molecules has been determined by STM and IR spectroscopy. In contrast, multilayer films are formed after long adsorption times. Single molecular wires could be formed between a gold STM tip and a surface with a low coverage of the adsorbed dithiols, and their electrical behavior was investigated. Molecular conductivity was determined either by the repeated measurement of I(s) curves or by recording I−V curves for different tip−sample separations. These methods concurred in producing a value of (0.5 ± 0.1) nS for the single-molecule conductivity of the α,ω-viologen dithiol molecule HS−6V6−SH. The high conductivity of HS−6V6−SH, as compared to that of HS−C12−SH, may be related to the low-lying LUMO, which provides a barrier indentation for electron transport in a two-step electron-transfer mechanism.

Dissolution of the (104) surface of magnesite (MgCO3) was studied as a function of bulk solution pH over the range 2.0 &lt; pH &lt; 5.0 at 60 °C using atomic force microscopy (AFM) with well-defined hydrodynamics. The experimental data and corresponding solution of the convective-diffusion equation for the system revealed that magnesite dissolution is kinetically inhibited by a factor of 10²−10⁴ relative to the proton mass transport limit. The dissolution flux was found to vary nonlinearly with the surface concentration of H⁺, [H⁺]y=0, and that inclusion of the homogeneous chemical kinetics of H⁺ consumption in the system to form carbonic acid was unnecessary. The nonlinear behavior was best represented by a Langmuir isotherm for proton adsorption in which the adsorbed entity consists of a surface complex containing more than one proton. The apparent surface kinetic detachment coefficient, k%@mt;sys@%%@/xs;55;%lnwidth@%‘%@/xs;63;(%lnwidth-x55)@%%@mh;-x63@%%@mx@% n, for this surface complex was determined to be 5 × 10^-12 mol cm^-2 s^-1, but the determination of a particular coordination number, n, of this detachment complex was not possible based on the experimental data. The velocity of dissolving + steps was found to be constant, within error, over the entire experimental pH range, whereas the dissolution flux varied by over an order of magnitude in this same range. The AFM images revealed a dramatic increase in step density associated with a large increase in dissolution flux that was attributed to the protonation of terrace-adsorbed carbonate sites (i.e., adions). We propose that the intrinsic protonation constant, Kint, differs for adions, kink, step, and terrace sites based on the AFM observations of surface and step morphology as a function of pH.

Current methods of measurement of proprioceptive function depend on the ability to detect passive movement (kinaesthesia) or the awareness of joint position (joint position sense, JPS). However, reports of proprioceptive function in healthy and pathological joints are quite variable, which may be due to the different methods used. We have compared the validity of several frequently used methods to quantify proprioception.Thirty healthy subjects aged between 24 and 72 years underwent five established tests of proprioception. Two tests were used for the measurement of kinaesthesia (KT1 and KT2). Three tests were used for the measurement of JPS, a passive reproduction test (JPS1), a relative reproduction test (JPS2) and a visual estimation test (JPS3).There was no correlation between the tests for kinaesthesia and JPS or between the different JPS tests. There was, however, a significant correlation between the tests for kinaesthesia (r = 0.86). We conclude therefore that a subject with a given result in one test will not automatically obtain a similar result in another test for proprioception. Since they describe different functional proprioceptive attributes, proprioceptive ability cannot be inferred from independent tests of either kinaesthesia or JPS.

A study was designed to evaluate the effect of supplementation with a low dose (0.9 g/d) of n-3 polyunsaturated fatty acids (n-3 PUFA) in fish oil on the oxidative modification of low-density lipoprotein (LDL) in a group of healthy volunteers. Eight volunteers were randomly selected from a larger fish oil supplementation study, and were required to take either 0.9g n-3 PUFA as fish oil (FO group) or 0.9g olive oil [control oil (CO group)] for 16 weeks. Oxidative modification of LDL was assessed by measuring concentrations of free cholesterol (FC), cholesteryl esters (CE) and cholesteryl linoleate hydroperoxide (Ch18:2-OOH) in LDL following copper-induced lipid peroxidation for 0, 2, 3 and 4 h. The composition of LDL fatty acids over 4 h of copper-induced oxidation was also investigated. LDL eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) compositions were significantly (P < 0.05) higher in the FO compared with the CO group, following supplementation. Linoleic acid (C18:2n-6), arachidonic acid (C20:4n-6), C20:5n-3 and C22:6n-3 were significantly (P < 0.05) oxidised in LDL following 4 h copper-oxidation. The proportions of palmitic acid (C16:0) (P < 0.05), palmitoleic acid (C16:1) (P < 0.05), stearic acid (C18:0), and oleic acid (C18:1) increased in the FO and CO groups, after 4 h of copper-oxidation. Concentrations of cholesteryl oleate (Ch18:1), cholesteryl linoleate (Ch18:2n-6), cholesteryl arachidonate (Ch20:4n-6) and cholesteryl docosahexanoate (Ch22:6n-3) were significantly (P < 0.05) reduced following copper-stimulated oxidation, in both groups. Ch18:2-OOH concentrations were significantly increased (P < 0.05) following 3 h oxidation in both groups compared with 0 h copper-oxidation, but decreased after 4 h. There was no significant difference in concentrations of Ch18:2-OOH between the groups over the time-course of copper-mediated oxidation. The results of this study suggest that moderate dietary intakes of n-3 PUFA do not significantly influence the susceptibility of LDL to copper-induced oxidation in vitro.

We have measured step growth kinetics on barium sulfate (001) as a function of step length, supersaturation, and temperature. Using a one-dimensional nucleation model, we report kink detachment coefficients for 〈120〉 monolayer steps of w- = 114 (±14), 187 (±17), and 357 (±43) s^-1, at 90, 108, and 125 °C, respectively, giving an activation energy, Ea = 0.39 (± 0.05) eV. The kink formation energy, ε, was found to be 0.16 (±0.02) eV. The uncertainty in this energy is sufficient to envelop the experimentally determined kink densities, but the lack of increase in experimental kink density with increase in temperature points to kinetic limitations in the experiments. Due to the kinetic limitations of growth at kinks whether they are from diffusion or attachment, our results demonstrate that knowledge of the kink kinetics as a function of temperature is important in testing the applicability of the classical thermodynamic model to kinetic data.

The present study assessed the acute effects of p.o. administered ethanol (0, 22, 45, and 67 g) and diazepam (0, 10, 20 and 40 mg) in normal adult humans responding under a multiple schedule of acquisition and performance of 10-response sequences. In each component of the multiple schedule subjects were required to complete a different sequence of 10 responses in a predetermined order using three keys of a numeric keypad. In the acquisition component a new response sequence had to be acquired each session. In the performance component the response sequence remained the same from session to session. The higher doses of ethanol (67 g) and diazepam (20 and 40 mg) increased overall percent errors above placebo levels; the lower doses of these compounds had no significant effect. The increases in percent errors were selective across the two schedule components. Ethanol increased percent errors significantly only in the acquisition component. Diazepam increased percent errors significantly in the acquisition component at a lower dose (20 mg) than was necessary to increase errors in the performance component (40 mg). Ethanol (67 g) and diazepam (40 mg) decreased overall response rates as an orderly function of dose. In contrast to the percent errors measure, the effects on response rates were not significantly different across the performance and acquisition components. Peak effects on percent errors and response rates varied between 30 and 70 min and 45 and 80 min postdrug for ethanol and diazepam, respectively, and the duration of effects of the higher doses was greater than 3 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-dependent cocaine users participated in a two-phase experiment conducted under controlled laboratory conditions. During phase 1, subjects sampled intranasal cocaine (100 mg) and placebo (96 mg lactose +4 mg cocaine) in separate sessions and under double-blind conditions. Sampling sessions were followed by a single choice session in which subjects made a maximum of ten choices between 10 mg unit doses of cocaine or placebo. Only subjects who reliably (≥70%) chose cocaine over placebo in phase 1 participated in phase 2. During phase 2, subjects participated in a series of nine experimental sessions conducted on different days in which they were pretreated with varying doses of alcohol (placebo, 0.5, and 1.0 g/kg) and made a maximum of ten choices between 10 mg unit doses of cocaine and an alternative reinforcer (i.e., varying amounts of money). Visual-analog ratings of drug effects and cardiac function were monitored across all experimental sessions. Cocaine was reliably chosen over placebo by the majority (9 of 11) of subjects during phase 1, demonstrating that the drug functioned as a reinforcer. During phase 2, alcohol pretreatment significantly increased choice of cocaine over the alternative reinforcer, while increasing monetary value decreased cocaine choice. Ratings on some visual-analog scales (e.g., good effects) paralleled cocaine choice, with alcohol pretreatment increasing ratings and greater monetary value decreasing them. Cardiac output increased above baseline levels across all alcohol and monetary conditions, but maximal effects were observed during sessions involving pretreatment with the active alcohol doses. Overall, these results demonstrate (a) that alcohol can increase preference for cocaine over alternative reinforcers and thereby may thwart efforts to reduce or abstain from cocaine use, (b) that availability of an alternative, non-drug reinforcer can effectively decrease preference for cocaine, and (c) that combined use of alcohol and cocaine increases cardiac risk compared to use of cocaine alone.

The maintenance of a characteristic level of nicotine in a smoker's body is referred to as nicotine regulation. Considerable research has examined this question of whether smokers regulate nicotine intake. This is because nicotine regulation raises the question of whether smokers who, to decrease their intake of tar, switch to low tar/low nicotine cigarettes will increase the number and/or intensity of cigarettes smoked. Although the results of studies examining nicotine regulation are reported as generally consistent, considerable variability exists across these analyses such that the health hazards of smoking low tar/nicotine cigarettes remains uncertain. In the present analysis, these studies were analyzed to ascertain whether a behavioral-economic interpretation could better quantify the effects of changing nicotine yield on individuals' nicotine and smoke consumption. Specifically, 17 nicotine-regulation studies were reanalyzed using a unit-price analysis (i.e., cost-benefit analysis). The reanalysis showed less variability across regulation studies than previously reported; a positively-decelerating demand curve was found across most studies, consistent with previous unitprice analyses of food- and drug-maintained behavior. The benefits of this reanalysis versus the traditional regulation interpretation are that the behavioral economics approach: 1) brings unity to a variable set of data, 2) shows a nonlinear relationship, previously considered to be linear, between nicotine consumption and nicotine yield, 3) shows that nicotine yields higher, and not lower, than the smoker's usual brand decrease smoke consumption and thus decreases consumption of the harmful agents in tobacco, 4) better quantifies the data and provides a more parsimonious interpretation that generalizes to other drugs and food-maintained behavior in humans and nonhumans and, 5) integrates behavioral and pharmacological factors that control the consumption of reinforcers. These results suggest the value of behavioral economics in the study of consumptive behaviors and clinically suggest, in agreement with the studies contained herein, that decreasing the smoker's usual nicotine yield can have potential healthrisks for smokers who are unable to stop smoking.