Fingerprints of hydrogen bonding in the terahertz dynamics of ethanol and water: An inelastic x-ray scattering study

We used inelastic x-ray scattering methods to measure the terahertz spectrum of density fluctuations of ethanol in both liquid and solid phases. The results of a Bayesian inference-based lineshape analysis with a multiple excitation model and the comparison with a previous similar analysis on water indicate that the different structures induced by hydrogen bonds in ethanol and water have a profound influence on the respective dynamic responses, the latter being characterized by longer living and better resolved high-frequency acoustic excitations. In addition, we compare these findings with those obtained with an alternative approach based on the exponential expansion theory and ensuring sum rules fulfillment, demonstrating that the model's choice directly impacts the number of spectral modes detected.

Ice phonon spectra and Bayes inference: a gateway to a new understanding of terahertz sound propagation in water

Understanding how molecules engage in collective motions in a liquid where a network of bonds exists has both fundamental and applied relevance. On the one hand, it can elucidate the ``ordering" role of long-range correlations in an otherwise strongly dissipative system; on the other hand, it can inspire new avenues to control such order to implement sound manipulation.Water represents an ideal investigation case to unfold these general aspects and, across the decades, it has been the focus of thorough scrutiny. Despite this investigative effort, the spectrum of terahertz density fluctuations of water largely remains a puzzle for Condensed Matter physicists. To unravel it, we compare previous scattering measurements of water spectra with new ones on ice. Thanks to the unique asset of Bayesian inference, we draw a more detailed portrayal of the phonon response of ice. The comparison with the one of liquid water challenges the current understanding of density fluctuations in water, or more in general, of any networked liquid.

Trends and gaps in climate change and health research in North America

The Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (2014) assessed the state of climate change and health knowledge, globally through the Human Health: Impacts, Adaptation, and Co-Benefits Chapter and regionally through chapters, such as the North America Chapter. With IPCC's 6th Assessment Report scheduled to be released in 2021-22, we asked: how has climate change and health research in North America advanced since the IPCC's 5th Assessment Report in 2014? Specifically, we systematically identified and examined trends in the extent, range, and nature of climate-health research conducted in North America. We used a scoping review methodology to systematically identify literature and map publication trends. A search string was used to search five academic databases. Two independent reviewers first screened titles and abstracts, and then the full texts of articles for relevance. Research articles and reviews using systematic methods published since 2013 were eligible for inclusion, and no language restrictions were applied. To be included, articles had to measure and link climatic variables or hazards to health outcomes in North America. Relevant articles were analysed using descriptive statistics to explore publication trends. The number of climate-health articles has significantly increased since the last IPCC Assessment Report. Published research about climate change impacts, heat-related mortality and morbidity, and respiratory illness taking place in urban centres and in the USA continue to dominate the North American climate-health literature, reflected by the high proportion of articles published. Important research gaps on previously neglected climate-sensitive health outcomes, however, are beginning to be filled, including climate change impacts on mental health, nutrition, and foodborne disease. We also observed progress in research that included future projections of climate-health risks; however, projection research is still relatively nascent and under-studied for many climate-sensitive health outcomes in North America, and would benefit from considering social and demographic variables in models. Important research disparities in geographical coverage were noted, including research gaps in Canada and Mexico, and in rural and remote regions. Overall, these publication trends suggest an improved understanding of exposure-response relationships and future projections of climate-health risks for many climate-sensitive health outcomes in North America, which is promising and provides an evidence-base to inform the IPCC 6th Assessment Report. Despite these advancements and considering the urgent policy and practice implications, more research is needed to deepen our understanding of climate-sensitive health outcomes, as well as examine new arising issues that have limited evidence-bases. In particular, transdisciplinary and cross-sector research, that includes the social sciences, examining current and future climate-health adaptation, mitigation, and the adaptation-mitigation nexus should become a top priority for research, given the urgent need for this evidence to inform climate change policies, actions, and interventions.

Adjuvant Chemotherapy with Fluorouracil and ccnu in Colon Cancer. Results of a Multicentric Randomized Study

To establish the effectiveness of adjuvant chemotherapy in patients with colon cancer after radical surgery, from 1980 to December 1983, 263 patients were randomized in a multicentric study to no further treatment (131 patients) or to a combination of fluorouracil (5-FU) (400 mg/m2 i.v., days 1–5) and lomustine (CCNU) (100 mg/m2 per os on day 5) every 6 weeks for 9 cycles (132 patients). The two groups were well balanced for age, sex, histology, tumor and nodal extent. Chemotherapy was not given to 30 of the 132 randomized patients, and of 98 treated patients only 38 completed the entire protocol. Analysis, as intention to treat, at 54 months did not show any significant difference between the two treatment groups in terms of relapse-free survival (surgery alone, 74.5%; surgery+adjuvant chemotherapy, 70.9%; p = 0.91). In contrast, a significant difference was observed in overall survival (surgery alone, 78.8%; surgery+adjuvant chemotherapy, 60.8%; p = 0.04). The sites of relapse were identical in the two treatment arms. In conclusion, from this study it appears that adjuvant chemotherapy with 5-FU and CCNU seems to have no efficacy in the cure rate of colon cancer patients.

Clinical Evaluation of High Weekly Intravenous Doses of Methotrexate in Advanced Oropharyngeal Carcinoma

Methotrexate (MTX) was given by weekly rapid intravenous injections to 27 patients with inoperable oropharyngeal carcinoma. 9 cases were untreated while 18 had received radiotherapy or chemotherapy before administration of MTX. In 20 cases the dose was 40 mg/m2/week (patients over 50 years) and in 7 cases 60 mg/m2/week (table 1). In responsive patients, maintenance treatment was given at the dose of 15 mg/m2 every 4 days either orally or intramuscularly. 23 cases were adequately evaluable, i.e. they received treatment for a minimum of 3 weeks. Response to treatment was evaluated according to Karnofsky's scale. Considering only category 1 regressions, 11/16 (75%) patients adequately treated with 40 mg/m2 showed objective improvement and respectively 4/7 (57%) given 60 mg/m*. 8 out of 15 cases (41%) with category 1 response showed a regression greater than 50%. The mean duration of response for category 1 patients was 3.5 months, while the longest regression lasted 9 months (table 2). 18 patients had one or more side effects: 9 had oral lesions or gastroenteritis, 12 bone marrow depression, 3 hepatic and 1 renal toxicity. One patient died from hepatic and renal toxicity; in the remaining cases the side effects were quickly reversible (table 3). The percent regression rate for category 1 response and its average duration obtained with intravenous MTX seems comparable to intraarterial infusion (table 4). Systemic toxicity seems also comparable (table 5). Furthermore, intravenous administration obviates the typical local complications occurring with intra-arterial treatment and therapy can be given also at outpatients. For this reason, intravenous administration of MTX is preferred to intra-arterial infusion in the control of primary inoperable oropharyngeal carcinomas, provided no severe depression of liver, kidney and bone marrow is present.

Clinical Evaluation of High Intermittent Intravenous Doses of Methotrexate in Advanced Lung Cancer

Methotrexate (MTX) was given by weekly intravenous injections to 43 patients with inoperable or metastatic lung cancer (32 cases were untreated while 11 received radiotherapy or chemotherapy prior to administration of MTX). In 35 cases the dose was 40 mg/m2/week and in 8 cases 60 mg/m2/week. 36 patients were adequately evaluable. In most cases it was possible to continue the administration of MTX for 6–8 weeks (table 1). In responsive cases maintenance treatment was given at the dose of 15 mg/m2 every 4 days either orally or intramuscularly. Response to treatment was evaluated according to Karnofsky's scale. Considering only the category I responses 12/30 patients adequately treated with 40 mg/m2 showed objective improvement and 2/6 of those given 60 mg/m2. Regressions were short-lived and in no case did they last longer than 5 months (table 2). Regressions were seen in practically all histologic types (table 3). Of 43 patients receiving MTX 30 (70%) had one or more side-effects: 27 showed oral or gastrointestinal toxicity, 8 varying degrees of bone marrow depression, 6 hepatic and 4 renal toxicity. Four patients died because of toxicity, renal damage being present in all cases (table 4). The relatively small number of consistent objective regressions (about 40%), their short duration and the high incidence of severe toxicity, as observed in the present series, indicate that weekly high-dose intravenous MTX is of moderate therapeutic usefulness in lung cancer.

Benign Smooth Muscle Cell Metaplasia in Breast

Three different benign breast lesions showing smooth muscle cells in the stroma are reported. Benign smooth muscle cells are rarely found in the breast, and it is likely that they originate from metaplastic changes of the stroma itself.

Investigation of the ^{10}Li shell inversion by neutron continuum transfer reaction

This Letter reports a study of the highly debated ^{10}Li structure through the d(^{9}Li,p)^{10}Li one-neutron transfer reaction at 100 MeV. The ^{10}Li energy spectrum is measured up to 4.6 MeV and angular distributions corresponding to different excitation energy regions are reported for the first time. The comparison between data and theoretical predictions, including pairing correlation effects, shows the existence of a p_{1/2} resonance at 0.45±0.03  MeV excitation energy, while no evidence for a significant s-wave contribution close to the threshold energy is observed. Moreover, two high-lying structures are populated at 1.5 and 2.9 MeV. The corresponding angular distributions suggest a significant s_{1/2} partial-wave contribution for the 1.5 MeV structure and a mixing of configurations at higher energy, with the d_{5/2} partial-wave contributing the most to the cross section.

Multiple-wave diffraction in high energy resolution back-reflecting x-ray optics

We have studied the effects of multiple-wave diffraction in a novel optical scheme recently published by Shvyd'ko et al. utilizing Bragg diffraction of x rays in backscattering geometry from asymmetrically cut crystals for achieving energy resolutions beyond the intrinsic width of the Bragg reflection. By numerical simulations based on dynamic x-ray diffraction and by experimentation involving two-dimensional angular scans of the back-reflecting crystal, multiple-wave diffraction was found to contribute up to several tens percent loss of efficiency but can be avoided without degrading the energy resolution of the original scheme by careful choice of azimuthal orientation of the diffracting crystal surface and by tilting of the crystal perpendicular to the dispersion plane.

The single particle dynamics of iodine in the Sachs-Teller regime: an inelastic x-ray scattering study

The high frequency dynamics of liquid iodine has been investigated by deep inelastic x-ray scattering at exchanged wave-vectors (q) ranging from 2.5 to 15 Å(-1). The experimental data have been analyzed in the frame of the Sachs-Teller theory of the molecular spectrum while accounting for final state corrections to the lineshape. The performed data analysis carries insights on physical quantities as relevant as the mean rototranslational kinetic energy and the mean square Laplacian of the intermolecular potential. In both cases the measured values are consistent with corresponding theoretical expectations.

High frequency dynamics in liquids and supercritical fluids: A comparative inelastic x-ray scattering study

The microscopic dynamics of four prototype systems (water, ammonia, nitrogen, and neon) across the critical temperature has been investigated by means of high-resolution inelastic x-ray scattering. The experimental line shape has been described using a model based on the memory function formalism. Two main relaxations, the thermal and the structural one, were observed in all the investigated systems. We found that the microscopic mechanism driving the structural relaxation clearly changes, being mainly governed by intermolecular bond rearrangements below the critical temperature and by binary collisions above it. Moreover, we observed that the relative weight of the thermal relaxation systematically increases on approaching the critical temperature, thus allowing for the observation of a transition from an adiabatic to an isothermal regime of sound propagation. Finally, we found the presence of an additional instantaneous relaxation, likely related to the coupling between collective vibrational modes and intramolecular degrees of freedom.

On the anomalous behaviour of microscopic diffusion of liquid water

We propose here a new interpretation of recent quasi-elastic neutron scattering (QENS) measurements on water. A line-shape analysis based on a stretched exponential ansatz for the time decay of density fluctuations enabled us to observe an anomalous dependence on the exchanged momentum of relevant relaxation parameters. We discuss this effect and relate it to an a priori uncorrelated anomaly, previously evidenced by diffraction measurements.

High-frequency dynamics of liquid and supercritical water

The dynamic structure factor S(Q,omega) of water has been determined by high-resolution inelastic x-ray scattering (IXS) in a momentum (Q) and energy (E) transfer range extending from 2 to 4 nm{-1} and from +/-40meV . IXS spectra have been recorded along an isobaric path (400bar) in a temperature (T) interval ranging from ambient up to supercritical (T>647K) conditions. The experimental data have been described in the frame of the generalized hydrodynamic theory, utilizing a model based on the memory function approach. This model allows identifying the active relaxation processes which affect the time decay of density fluctuations, as well as a direct determination of the Q , T , and density (rho) dependencies of the involved transport parameters. The experimental spectra are well described by considering three different relaxation processes: the thermal, the structural, and the instantaneous one. On approaching supercritical conditions, we observe that the microscopic mechanism responsible for the structural relaxation is no longer related to the making and breaking of intermolecular bonds, but to binary intermolecular collisions.

Structural and collisional relaxations in liquids and supercritical fluids

The dynamic structure factor S(Q,omega) of both associated (water and ammonia) and simple fluids (nitrogen and neon) has been determined by high-resolution inelastic x-ray scattering in the 2-14 nm(-1) momentum transfer range. A line-shape analysis with a generalized hydrodynamic model was used to study the involved relaxation process and to characterize its strength and time scale. We observe that in the liquid phase such a process is governed by rearrangements of intermolecular bonds, whereas in the supercritical region it assumes a collisional nature.

Quasielastic neutron scattering investigation of the pressure dependence of molecular motions in liquid water

We report on a high-resolution, high-statistics, quasielastic neutron scattering (QENS) experiment on liquid water, aimed at accurately measuring the pressure dependence of the single-particle dynamic response function at low wave vector transfers, namely, from 0.26 to 1.32 A(-1). High-pressure QENS data were collected along the T = 268 K isothermal path over the rather extended pressure range of 80 up to 350 MPa, a thermodynamic region so far unexplored by this microscopic technique. The analysis of the measured line shapes enabled us to draw a consistent picture of the wave vector and pressure dependences of the diffusion mechanisms in liquid water, against which the most recent models for water dynamics can be checked. In close similarity with the case of supercooled water, the relaxing-cage model was found to provide a quantitatively more accurate description of the molecular motions and their pressure evolution in liquid water.

Signatures of quantum behavior in the microscopic dynamics of liquid hydrogen and deuterium

We discuss the microscopic dynamics and structure of liquid hydrogen and deuterium, as probed by inelastic x-ray scattering measurements. Samples are kept in corresponding thermodynamic conditions, at which classical systems are expected to exhibit the same dynamic and static responses. On the contrary, we observe clear differences revealing the onset of quantum deviations, both in the broadening of inelastic excitations and in the position of the first sharp diffraction peak. These features are discussed, compared to path-integral Monte Carlo simulations, and finally associated with the different de Broglie wavelengths of the two isotopes.

High-frequency longitudinal and transverse dynamics in water

High-resolution, inelastic x-ray scattering measurements of the dynamic structure factor S (Q,omega) of liquid water have been performed for wave vectors Q between 4 and 30 nm(-1) in distinctly different thermodynamic conditions ( T=263-420 K ; at, or close to, ambient pressure and at P=2 kbar ). In agreement with previous inelastic x-ray and neutron studies, the presence of two inelastic contributions (one dispersing with Q and the other almost nondispersive) is confirmed. The study of their temperature and Q dependence provides strong support for a dynamics of liquid water controlled by the structural relaxation process. A viscoelastic analysis of the Q -dispersing mode, associated with the longitudinal dynamics, reveals that the sound velocity undergoes a complete transition from the adiabatic sound velocity ( c(0) ) (viscous limit) to the infinite-frequency sound velocity ( c(infinity) ) (elastic limit). On decreasing Q , as the transition regime is approached from the elastic side, we observe a decrease of the intensity of the second, weakly dispersing feature, which completely disappears when the viscous regime is reached. These findings unambiguously identify the second excitation to be a signature of the transverse dynamics with a longitudinal symmetry component, which becomes visible in S (Q,omega) as soon as the purely viscous regime is left.

Pressure evolution of the high-frequency sound velocity in liquid water

The high-frequency sound velocity v( infinity ) of liquid water has been determined to densities of 1.37 g/cm(3) by inelastic x-ray scattering. In comparison to the hydrodynamic sound velocity v(0), the increase of v( infinity ) with density is substantially less pronounced, indicating that, at high density, the hydrogen-bond network is decreasingly relevant to the physical properties of liquid water. Furthermore, we observe an anomaly in v( infinity ) at densities around 1.12 g/cm(3), contrasting the smooth density evolution of v(0).

Deep inelastic atomic scattering of x rays in liquid neon

An inelastic x-ray scattering (IXS) experiment in liquid neon has been performed in the +/-100 meV exchanged energy range and at exchanged wave numbers, q, comprised between 1 and 16 A(-1). At the highest probed q's a deep inelastic scattering regime is reached where the Ne core electrons, after collision with the x rays, recoil almost freely with an effective mass equal to the Ne atomic mass. IXS in this high q regime is here shown to provide quantitative information on the atomic momentum distribution of liquid Ne, thus supplying a complementary technique to neutron scattering. There are several open problems in quantum and classical liquids which can benefit from this complementarity.

Quantum effects in the dynamics of He probed by inelastic x-ray scattering

Quantum effects in the teraherz dynamics of supercritical 4He have been studied as a function of both density rho and temperature T; they have been characterized through their effects on the second and third spectral moments of the dynamic structure factor S(Q, omega), measured by the inelastic x-ray scattering (IXS) technique. The IXS spectra were collected in the low-Q region below and around the position of the first diffraction peak Q(m), i.e., in a range relatively unusual in this kind of investigation. The measured spectral moments clearly show a departure from their high-T classical expected values. We observe, moreover, that the amplitude of quantum deviations increases slightly with increasing density. This experimental method allows us to extract, even in a region where the dynamics still maintains a collective character, such typical single particle properties as the mean atomic kinetic energy.

Deep-inelastic neutron scattering determination of the single-particle kinetic energy in solid and liquid 3He

An experimental determination of the single-particle mean kinetic energies for 3He along the T = 2.00 K isotherm in the dense liquid and in the solid hcp and bcc phases is reported. Deep-inelastic neutron scattering measurements at exchanged wave vectors ranging from 90.0 to 140.0 A(-1) have been performed in order to evaluate, within the framework of the impulse approximation, the molar volume dependence of the kinetic energy. The results are found in excellent agreement with recent diffusion Monte Carlo simulations.

Nature of the short wavelength excitations in vitreous silica: An X-Ray brillouin scattering study

The dynamical structure factor [ S(Q,E)] of vitreous silica has been measured by inelastic x-ray scattering varying the exchanged wave vector ( Q) at fixed exchanged energy ( E)-an experimental procedure that, contrary to the usual one at constant Q, provides spectra with much better identified inelastic features. This allows us to obtain the first direct evidence of Brillouin peaks in the S(Q,E) of SiO2 at energies above the boson peak (BP) energy, a finding that excludes the possibility that the BP marks the transition from propagating to localized dynamics in glasses.

Determination of the short-wavelength propagation threshold in the collective excitations of liquid ammonia

The dynamics structure factor S(Q,E) of liquid ammonia l-NH3 at T = 200 K and at its vapor pressure has been measured by inelastic x-ray scattering (IXS) in the 1-15 nm(-1) momentum transfer ( Q) range. Contrary to previous IXS studies on other associated liquids and glasses, in l-NH3 a large inelastic signal is observed up to Q = 15 nm(-1). This, enabling S(Q,E) measurements as a function of Q at constant E transfer, allows us to demonstrate experimentally the transition from a propagating dynamics regime, where the acoustic excitation energy linearly disperses with Q, to a high-Q regime, where it is no longer possible to observe a dominant excitation in the S(Q,E).

Viscoelastic behavior of water in the terahertz-frequency range: an inelastic x-ray scattering study

High-resolution, inelastic x-ray scattering measurements of the dynamic structure factor S(q,omega) of liquid water in the THz frequency range have been performed as a function of wave vector q (1-7 nm(-1)) and temperature T (273-473 K), using pressure (0-1.5 kbar) to keep the density at rho approximately 1 g/cm(3). We show that, for q<or=2 nm(-1), the S(q,omega) spectra can be consistently explained in terms of a hydrodynamic formalism which includes a viscoelastic, q-independent contribution to the memory function for the density fluctuations. This allows us to extract values for the infinite frequency sound velocity and for the structural relaxation time which are found to compare favorably with those obtained using techniques which probe a lower-frequency range. As a consequence, the atomic dynamics in water is shown to have a homogeneous character down to a length scale of approximately 3 nm. At q>2 nm(-1), we find that the viscoelastic contribution to the memory function becomes q dependent. Thus this work provides a view on the evolution of the collective dynamics of water across the q region where the continuum approximation inherent in the hydrodynamic formulation begins to fail. The physical consequences of such a result are discussed in some detail.

An immunohistochemical study of progesterone receptor in thyroidal Hürthle cells tumors

Estrogen (ER) and progesterone (PgR) receptors are commonly represented on normal and neoplastic thyroid tissues, while a few data are available about their expression in Hürthle cells tumors. Seventeen patients who underwent thyroidectomy for a neoplasia that showed oxyphilic elements were studied by an immunohistochemical method and the presence of PgR in the 30% of them, was demonstrated, while no ER expression could be found. We tried, therefore, to establish a correlation between these proteins and age, sex or indexes of the supposed estro-progestinic concentration of our patients. None of these factors resulted significantly related to the receptors expression. Since PgR are expressed in the oxyphilic cells neoplasms, further studies on both ER, and PgR are needed in order to point out their possible biological importance.

Correlation between plasma or blood transfusion and survival after curative surgery for colorectal cancer

Out of 473 patients operated radically for colon or rectal cancer different survival curves have been calculated according to whether they had received or not blood or plasma transfusions during their hospital stay. The non-transfused patients have a better 5-year survival rate and the difference is statistically significant both including and not including Duke's C stage cases. Anemia on hospital admission, on the contrary, does not seem to influence patients survival. Immune depression after blood or plasma transfusion is a very well known phenomenon in transplant surgery and actually depends on the infusion of leucocytes. Is not yet clearly demonstrated that in cancer surgery immune depression may lead to a poorer survival of transfused patients but several papers, including ours, suggest that this effect is very likely. At present in cancer patients it is preferable to limit transfusions to the minimum. If they are absolutely necessary leucocyte poor or, better still, leucocyte free preparations should be administered.

Urogenital dysfunction after abdominoperineal resection for carcinoma of the rectum

The long-term urogenital dysfunctions in 46 of 104 surviving patients submitted to abdominoperineal resection for rectal carcinoma between 1972 and 1986 were collected and assessed. Urinary retention was present in 41 percent of the men and 35 percent of women, while incontinence was present in 10 percent of men and 29 percent of women. Impotence was reported by 59 percent of the males, all sexually active before surgery. Dyspareunia was present in 50 percent of the women in the study. The possibility of treating prostatic hypertrophy concurrently with abdominoperineal resection in selected cases to avoid urinary retention is discussed. The limited number of responders to the survey may interfere with the global statistical significance.

[Neoplastic occlusion of the right colon]

On the basis of more than 10 years' clinical experience of 122 patients operated on for cancer of the right colon, stress is laid on intestinal occlusion which is one of the most frequent complications of this pathology. The factors that make the event to be avoided and that lead to the poor short and long-term results are analysed.

Rating depression and anxiety after mastectomy: observer versus self-rating scales

Paykel's Clinical Interview for Depression (CID), an observer-rated scale, and Kellner's Symptom Questionnaire (SQ), a self-rating inventory, were administered to twenty-six patients with breast cancer: 1) the day prior to discharge after mastectomy or lumpectomy, 2) after six months, during a follow-up outpatient visit. There were no significant changes in depression and anxiety (except for self-rated anxiety) and, indeed, there were very high test-retest correlations. Observer and self-rated assessments were significantly related, and these correlations improved on outpatient follow-up. DSM-III-R diagnoses of affective illness (mood and anxiety disorders) based on pre-established cut-offs of the CID, showed considerable stability, particularly as to major depressive illness.

Survival and complications after radical surgery for carcinoma of the rectum

The results of 164 abdominoperineal resections and 87 anterior resections carried out between 1972 and 1985 for cancer of the rectum were reviewed, assessed, and compared. The problems with anterior resection included a 1.1% hospital mortality and a 5.4% anastomotic failure rate in the 73 manual sutures and 28.5% in the 14 mechanical sutures; recurrence rate was 15.4% and the global 5-year-survival was 62%. There was no mortality in the Miles series; the recurrence rate was 4.8% and the 5-year-survival rate was 53.5%. Urogenital complications after Miles were found in 86.9%: urinary alone 10.8%, sexual alone 19.5%, both 56.5%.

[Our experience with ischemic colitis]

Personal experience in seven cases of ischaemic colitis that required surgery is reported. The aetiological, pathological and clinical features of the disease are then considered.