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Highly regulated basins have traditionally required management practices to mitigate the negative environmental impacts and ensure human well-being. This paper proposes and assesses environmental and water supply deficit indicators to assist in the management of environmental flows (e-flows). For that, a water allocation model is applied, and hydrological alteration, habitat alteration and water supply indicators are quantified, normalized and integrated into a general basin management indicator. This basin management indicator is analyzed for four management approaches and seven e-flow scenarios in the Júcar River Basin (eastern Spain). Hydrological alteration indicators show a less pronounced alteration in the river sections located upstream of the basin while a higher alteration in the downstream sections. As for the habitat indicators, they experience an improvement compared to the natural regime. Based on the values of the basin management indicator, the best e-flow scenario to adopt in the Júcar River Basin is selected. The indicators proposed in this work are useful for supporting decision-making regarding the planning and management of e-flows in regulated river basins worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

This paper presents a methodology to assess the effects of management strategies of environmental flows on the hydrological alteration of river basins on a daily scale. It comprises the collection and analysis of data, the implementation and calibration of a water allocation model; the computation of the natural flow regime; and the estimation, normalization, and aggregation of hydrological alteration indicators to obtain a global indicator of the hydrological alteration. The methodology was applied to a case study in the Iberian Peninsula: The Orbigo River basin, which belongs to the Duero River basin district. For that, three management scenarios were defined: the current scenario, a scenario without any environmental flow and the scenario with the environmental flows initially projected for the period 2022-2027. These scenarios were modelled with the SIMGES water allocation model, which is calibrated in the study site, and the hydrological alterations in four river stretches with different locations and characteristics were assessed. The implications of each environmental flow scenario on the demand reliabilities were also analysed. The global indicator of hydrological alteration obtained in the projected scenario was greater (better) than those of the other two scenarios, but the reliabilities of the water demands were worse. The methodology proposed in this work can be helpful to design environmental flow regimes considering both the effects on the hydrological alteration and the implication on the water demand reliabilities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

This study focuses on a novel type of methodology which connects Pan-European data to the local scale in the field of water resources management. This methodology is proposed to improve and facilitate the decision making within the planning and management of water resources, taking into account climate change and its expected impacts. Our main point of interest is focused on the assessment of the predictability of extreme events and their possible effects, specifically droughts and water scarcity. Consequently, the Júcar River Basin was selected as the case study, due to the ongoing water scarcity problems and the last drought episodes suffered in the Mediterranean region. In order to study these possible impacts, we developed a modeling chain divided into four steps, they are: i) data collection, ii) analysis of available data, iii) models calibration and iv) climate impact analysis. Over previous steps, we used climate data from 15 different regional climate models (RCMs) belonging to the three different Representative Concentration Pathways (RCPs) coming from a hydrological model across all of Europe called E-HYPE. The data were bias corrected and used to obtain statistical results of the availability of water resources for the future (horizon 2039) and in form of indicators. This was performed through a hydrological (EVALHID), stochastic (MASHWIN) and risk management (SIMRISK) models, all of which were specifically calibrated for this basin. The results show that the availability of water resources is much more enthusiastic than in the current situation, indicating the possibility that climate change, which was predicted to occur in the future has already happened in the Júcar River Basin. It seems that the so called "Effect 80", an important decrease in water resources for the last three decades, is not well contemplated in the initial data., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objectives: We aimed to study the risk of developing post-traumatic stress disorder (PTSD) symptoms in people who resided in an affected area by an extremely severe flood, and sociodemographic risk factors associated with this condition., Study Design: A geographic information system (GIS) was used to distribute the rainfall data. A case-control study was developed to study the relationship between PTSD and sociodemographic risk factors., Methods: To delineate the areas affected by the flood and the intensity of this rainfall in comparison with historical hydrological data, we employed geographical information systems (GIS). Then, we recruited a representative sample of the affected population and another population sample that lived at the time of this disaster in adjacent geographical areas that were not affected. Both groups were randomly selected in primary care practices, from December 1st 2012 to January 31st 2013. All participants, 70 from the affected areas and 91 from the non-affected, filled a sociodemographic questionnaire and the trauma questionnaire (TQ) to identify and rate PTSD symptoms., Results: Our GIS analysis confirmed that the amount of precipitation in 2012 in the areas affected by the flood was exceptionally high compared with historical average rainfall data (461l per square metre vs 265). Individuals who resided in the affected areas at the time of the flood were at much higher risk of developing PTSD symptoms (OR: 8.18; 95% CI: 3.99-17.59) than those living in adjacent, non-affected localities. Among the sociodemographic variables included in this study, only material and financial losses were strongly associated with the onset of PTSD (P < 0.001). Physical risk during this life-threatening catastrophe also indicated a positive correlation with later development of PTSD symptoms; however, it did not reach statistical significance (P = 0.06)., Conclusions: Populations affected by severe floods may suffer an increase of PTSD symptoms in the following months. This finding, along with the importance of material losses as a predictor for such disorder, may help develop effective plans to minimize the negative impact of these natural disasters on public health., (Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Water planning and the Integrated Water Resources Management (IWRM) represent the best way to help decision makers to identify and choose the most adequate alternatives among other possible ones. The System of Environmental-Economic Accounting for Water (SEEA-W) is displayed as a tool for the building of water balances in a river basin, providing a standard approach to achieve comparability of the results between different territories. The target of this paper is to present the building up of a tool that enables the combined use of hydrological models and water resources models to fill in the SEEA-W tables. At every step of the modelling chain, we are capable to build the asset accounts and the physical water supply and use tables according to SEEA-W approach along with an estimation of the water services costs. The case study is the Jucar River Basin District (RBD), located in the eastern part of the Iberian Peninsula in Spain which as in other many Mediterranean basins is currently water-stressed. To guide this work we have used PATRICAL model in combination with AQUATOOL Decision Support System (DSS). The results indicate that for the average year the total use of water in the district amounts to 15,143hm(3)/year, being the Total Water Renewable Water Resources 3909hm(3)/year. On the other hand, the water service costs in Jucar RBD amounts to 1634 million € per year at constant 2012 prices. It is noteworthy that 9% of these costs correspond to non-conventional resources, such as desalinated water, reused water and water transferred from other regions., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The primary effects of droughts on river basins include both depleted quantity and quality of the available water resources, which can render water resources useless for human needs and simultaneously damage the environment. Isolated water quality analyses limit the action measures that can be proposed. Thus, an integrated evaluation of water management and quality is warranted. In this study, a methodology consisting of two coordinated models is used to combine aspects of water resource allocation and water quality assessment. Water management addresses water allocation issues by considering the storage, transport and consumption elements. Moreover, the water quality model generates time series of concentrations for several pollutants according to the water quality of the runoff and the demand discharges. These two modules are part of the AQUATOOL decision support system shell for water resource management. This tool facilitates the analysis of the effects of water management and quality alternatives and scenarios on the relevant variables in a river basin. This paper illustrates the development of an integrated model for the Llobregat River Basin. The analysis examines the drought from 2004 to 2008, which is an example of a period when the water system was quantitative and qualitatively stressed. The performed simulations encompass a wide variety of water management and water quality measures; the results provide data for making informed decisions. Moreover, the results demonstrated the importance of combining these measures depending on the evolution of a drought event and the state of the water resources system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This paper describes two different GIS models - one stationary (GeoImpress) and the other non-stationary (Patrical) - that assess water quantity and quality in the Júcar River Basin District, a large river basin district (43,000km(2)) located in Spain. It aims to analyze the status of surface water (SW) and groundwater (GW) bodies in relation to the European Water Framework Directive (WFD) and to support measures to achieve the WFD objectives. The non-stationary model is used for quantitative analysis of water resources, including long-term water resource assessment; estimation of available GW resources; and evaluation of climate change impact on water resources. The main results obtained are the following: recent water resources have been reduced by approximately 18% compared to the reference period 1961-1990; the GW environmental volume required to accomplish the WFD objectives is approximately 30% of the GW annual resources; and the climate change impact on water resources for the short-term (2010-2040), based on a dynamic downscaling A1B scenario, implies a reduction in water resources by approximately 19% compared to 1990-2000 and a reduction of approximately 40-50% for the long-term (2070-2100), based on dynamic downscaling A2 and B2 scenarios. The model also assesses the impact of various fertilizer application scenarios on the status of future GW quality (nitrate) and if these future statuses will meet the WFD requirements. The stationary model generates data on the actual and future chemical status of SW bodies in the river basin according to the modeled scenarios and reflects the implementation of different types of measures to accomplish the Urban Waste Water Treatment Directive and the WFD. Finally, the selection and prioritization of additional measures to accomplish the WFD are based on cost-effectiveness analysis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome. Knowledge of this condition is scarce and, at present, no consensus exists with regards to the aetiology, prognosis, and treatment. Among patients with SCAD, cases involving the left main (LM) and the left anterior descending (LAD) and circumflex (Cx) arteries bifurcation are even more exceptional. Furthermore, the treatment of asymptomatic patients with involvement of these major vessels poses a major challenge for the cardiologists and cardiac surgeons. We report a case of complicated spontaneous left main coronary artery dissection in which we question what is the best initial treatment in these asymptomatic patients: conservative or early aggressive., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The Manzanares River, located in Madrid (Spain), is the main water supplier of a highly populated region, and it also receives wastewater from the same area. The effluents of eight Waste Water Treatment Plants (WWTPs) downstream of the river, which represent 90% of the flow in the middle and lower parts of the river, are the primary sources of water pollution. Although the situation has improved slightly in the last two years, the water in the river is highly polluted, making it uninhabitable for aquatic life. Water quality modelling is typically used to assess the effect of treatment improvements in water bodies. In this work, the GESCAL module of the Aquatool Decision Support System Shell was used to simulate water quality in the Manzanares River. GESCAL is appropriate for modelling in an integrated way water quality for whole water resources systems, including reservoirs and rivers. A model was built that simulates conductivity, phosphorous, carbonaceous organic matter, dissolved oxygen, organic nitrogen, ammonia, and nitrates. The period from October 2006 to September 2008 was selected for calibration due to the many treatment modifications that occurred during this time. An earlier and longer period, from October 2000 to September 2006, was used for validation. In addition, a daily model was used to analyse the robustness of the GESCAL model. Once the GESCAL model was validated, different scenarios were considered and simulated. First, different combinations of nutrient elimination among the different WWTPs were simulated, leading to the conclusion that investments have to focus on three of the proposed WWTPs. Moreover, these treatments will not be sufficient to maintain fish habitat conditions at all times. Additional measures, such as the increment of the flow in the river or oxygen injection, were simulated. Incrementing the flow of the Manzanares River has been shown to be an efficient means of increasing water quality, but this implies an increment in the risk of water scarcity situations in the Madrid water supply system., (Copyright 2010 Elsevier B.V. All rights reserved.)

Background: An increasing number of patients undergoing percutaneous interventions (PI) have experienced previous coronary artery bypass graft surgery (CABG). However, the impact of PI on outcomes in such patients is currently unclear. We evaluated the immediate and 1-year clinical outcomes of post-CABG patients who underwent PI in a tertiary center., Methods: From January-2005 to September-2006, 91 consecutive post-CABG patients underwent 197 stent implantations (84% drug-eluting stents) for 154 lesions. 58% were treated in the native coronary arteries, 34% in the grafts and 8% in both type of vessels. Major adverse cardiac events (MACE) were recorded in-hospital and at 1-year follow-up., Results: Procedural success rate was 95.6%. In-hospital MACE rate was 3.3%. At 1 year, the incidence of MACE was 18.6%: death occurred in 5.4% of the patients, myocardial infarction in 2.2%, and 10.9% of the patients underwent repeat revascularization (target lesion revascularization was required in 5.4%). Multivariate analysis revealed left ventricular ejection fraction <50% (OR 4.6, 95% CI 1.8 to 7.5, p=0.01) and multivessel intervention (OR 2.7, 95% CI 1.2 to 4.5, p=0.03) to be independent predictors of MACE at 1 year., Conclusions: Immediate results showed the safety and efficacy of percutaneous revascularization in post-CABG patients. The relatively low risk need for target lesion revascularization obtained is encouraging. Independent predictors of MACE at 1 year were left ventricular disfunction and multivessel intervention.

The "Euro-Lupus Cohort" is composed by 1000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium--the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors.

We have reconstructed, from experimental approximately 2 nm resolution X-ray solution scattering profiles, the corresponding shapes and sizes of myoglobin, troponin C, spermadhesin PSP-I/PSP-II, chymotrypsinogen A, superoxide dismutase, ovalbumin, tubulin, nitrite reductase, catalase, the structural change of troponin C upon dissociation of the two high affinity Ca(2+), and the solution model structure of a tandem pair of fibronectin type III cytoplasmic domains of integrin alpha6beta4 before determination of its crystal structure. To this purpose we have designed a new genetic algorithm which gradually explores a discrete search space and evolves convergent models made of several hundred beads (down to 0.3 nm radius) best fitting the scattering profile upon Debye calculation, without geometrical constraints or penalty for loose beads. This is a procedure of effective numerical transformation of the one-dimensional scattering profiles into three-dimensional model structures. The number of beads in models is correlated with the protein molecular mass (with one exception). The shape and approximate dimensions of each protein have been retrieved by a set of ten solution models, essentially superimposable with the available crystal structures., (Copyright 2000 Academic Press.)

We report an acute respiratory insufficiency following the removal of a large intrathoracic fibroma (3.1 kg) in a 6 year-old child, caused by a re-expansion pulmonary oedema (unilateral oedema occurring within one hour after expansion). This oedema improved rapidly and was followed by a well-tolerated pleural effusion. This complication is due to discrepancy between a small lung and a large thoracic cavity, due to the prolonged time course of the tumor growth. These oedemas are caused by rapid lung re-expansion, the volume of the removed tumor and the depth of postoperative pleural suction. The value of positive-end expiratory pressure is discussed.

Hepatitis C virus (HCV) is transmitted by organ transplantation. Consequently, several organ procurement organizations have imposed a moratorium on use of organs from anti-HCV positive donors. Because of the inadequate supply of cadaver kidneys for transplantation, we adopted a policy to transplant kidneys from anti-HCV donors into anti-HCV positive recipients. During the period between March 1990 and December 1992, 24 anti-HCV positive dialysis patients received a kidney from anti-HCV positive donors (group I) and 40 anti-HCV positive patients received a kidney from anti-HCV negative donors (group II). We compared the prevalence of liver disease, anti-HCV, HCV RNA, graft and patient survival between groups. Pre-transplantation 17 of 24 (71%) patients in group I and 31 of 40 (79%) of patients in group II had serum HCV RNA. Post-transplantation follow-up was 26 +/- 8 months and 30 +/- 10 months in groups I and II, respectively. During follow-up, elevated ALT levels were present in 7 of 24 (29%) and 16 of 40 (40%) of patients in groups I and II, respectively (P > 0.05). Post-transplantation, all patients in both groups retained anti-HCV. The prevalence of HCV RNA post-transplantation was 22 of 23 (96%) patients in group I and 30 of 39 (77%) of patients in group II (P > 0.05). Graft and patient survival in group I (96% and 100%, respectively) were not significantly different from those in group II (93% and 98%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

GDP liganded tubulin, which is inactive in microtubule assembly, polymerizes into rings more readily than the active GTP liganded protein. The structure of double rings made of highly purified GDP-tubulin has been characterized to 3 nm resolution with synchrotron X-ray solution scattering. The scattering profile has characteristic maxima due to closely packed double rings of 38 nm mean diameter, with a 5.5 nm mean spacing between the rings, and a 4.2 nm centre-to-centre spacing between non-globular tubulin monomers within both rings. There are probably 24 and 32 monomers in the inner and outer ring, respectively, and the double ring population is more than 75% homogeneous in size. Comparison of this double ring structure to the lattice of tubulin molecules in microtubules indicates that the tubulin rings are equivalent to pairs of protofilament segments curved tangentially to the microtubule surface, with bending angles of 30 degrees and 22.5 degrees per tubulin alpha beta dimer. When the rings are modelled employing the same non-globular tubulin monomer as in microtubules, the best computer fitted scattering profiles correspond to monomer orientations equivalent to two microtubule protofilaments coiled sideways, with same or opposite polarity. Rings constitute the equilibrium assembly state of GDP-tubulin, which is tensioned inside microtubules after GTP hydrolysis, causing their functional instability. In analogy with other nucleotide binding proteins, the inactive/active structural switch of tubulin is induced by the binding of the gamma phosphate and a coordinated Mg ion. It should involve domain rearrangements which cancel the bending of the tubulin dimer in the ring structure.

The structure of microtubules has been characterized to 3 nm resolution employing time-resolved X-ray scattering. This has revealed detailed structural features of microtubules not observed before in solution. The polymerization of highly purified tubulin, induced by the antitumour drug taxol, has been employed as a microtubule model system. This assembly reaction requires Mg2+, is optimal at a 1:1 taxol to tubulin heterodimer molar ratio, proceeds with GTP or GDP and is intrinsically reversible. The X-ray scattering profiles are consistent with identical non-globular alpha and beta-tubulin monomers ordered within the known helical surface lattice of microtubules. Purified tubulin-taxol microtubules have a smaller mean diameter (approx. 22 nm) than those induced by microtubule associated proteins or glycerol (approx. 24 nm), but nearly identical wall substructure to the resolution of the measurements. This is because the majority of the former consist of only 12 protofilaments instead of the typical 13 protofilaments, as confirmed by electron microscopy of thin-sectioned, negatively stained and ice-embedded taxol microtubules. It may be concluded that taxol induces a slight reduction of the lateral contact curvature between tubulin monomers. The main fringe pattern observed in cryo-electron micrographs is consistent with a simple 12 protofilament 3-start skewed lattice model. Cylindrical closure of this lattice can be achieved by tilting the lattice 0.8 degrees with respect to the microtubule axis. The closure implies a discontinuity in the type of lateral contacts between the tubulin monomers (regardless of whether these are of the -alpha-beta- or the -alpha-alpha-/-beta-beta- type), which indicates that lateral contacts and the subunit specificity of taxol binding are, to a large degree, equivalent.

The extent of hepatitis C virus (HCV) infection among kidney recipients was investigated in 67 patients by testing for anti-HCV paired serum samples, collected at time of transplantation and during follow-up (average 32 +/- 20 months). Prevalence of anti-HCV at transplant time was 48%, and was related to the time on dialysis and to the amount of blood transfusions. Following transplantation, nine (28%) seropositive patients lost anti-HCV and five (14%), previously seronegative, seroconverted. Anti-HCV was found to be positive in 92% of the patients with chronic liver disease who were on hemodialysis, but in 56% in kidney recipients with chronic hepatitis. Anti-HCV was positive in 50% of patients with resolving hepatitis before transplantation, but only in 21% of those with acute hepatitis following transplantation. This study confirms the high risk of HCV infection among hemodialysis and kidney recipient populations, and also that HCV is closely related with the length of time the patient is on hemodialysis as well as the number of blood units transfused. HCV is the main cause of acute and chronic liver disease in hemodialysis patients and of chronic liver disease in kidney recipients, but does not clearly influence the survival of the allograft nor that of patients.

The ability to stimulate an Mls-1 mixed lymphocyte reaction (MLR) is predominantly expressed by low density B lymphocytes in the spleen and peritoneal cavity of normal adult mice, and is absent in splenic B cells 1 month after lethal irradiation and reconstitution from autologous bone marrow. Coreconstitution of these mice with normal syngeneic peritoneal cells restores the stimulatory potential of splenic B cells, but sorted CD5+ or CD5- IgM+ lymphocytes from peritoneum are equally good stimulators, suggesting that functional Mls-1 expression may require long life spans and selection. Bone-marrow-reconstituted DBA/2 mice that fail to express Mls-1 antigens in the periphery nevertheless maintain T-cell receptor V beta 6 and 8.1 deletions among the newly formed T cells. These findings led us to directly investigate the Mls stimulatory ability of purified antigen-presenting cell populations inside the thymus. We report here that thymic B lymphocytes seem to represent the only intrathymic cell population able to stimulate Mls-1 MLR.

Antibodies to synthetic peptides from the alpha and beta-tubulin sequences were employed to study zones of this protein active in microtubule assembly. In purified calf brain tubulin, six short sequences, selected according to their hydrophilicity and conservation, were found to be accessible to their affinity-purified immunoglobulin G (IgG) antibodies, in a competition radioimmunoassay performed under non-assembly native conditions. This indicated that the six sequences are exposed on the surface of the tubulin alpha beta heterodimer. IgG antibodies to the alpha(430-443) and beta(412-431) sequences perturbed substoichiometrically the assembly of purified tubulin, inducing microtubule bundling and the formation of opened up structures. These positions, which are close to the C termini, were accessible to the anti-peptide antibodies in taxol-induced microtubules, Zn2(+)-induced tubulin sheets, Mg2(+)-induced tubulin rings and in PtK2 cell microtubules. This, together with the comparison of the sizes and gross shapes of the antibody probes and microtubules, suggested that these sequences might be located at the protruding parts of the protofilaments. Antibodies to positions alpha(155-168) did not react with microtubules, while the equivalent zone beta(153-165) was accessible. The alpha(214-226) and beta(241-256) sequences were antigenically occluded in the taxol microtubules, Zn2(+)-induced sheets and Mg2(+)-induced ring arrays, as well as in native microtubules from PtK2 cells, though they became reactive by fixation. This result strongly suggested that these two zones are close to tubulin-tubulin contact sites. A working model is proposed in which the positions alpha(214-226) and beta(241-256) are close to the axial contacts between heterodimers, which lead to protofilament formation, while the positions alpha(241-256) and beta(214-226) are suggested to be related to the alpha-beta binding interface within the heterodimer.

Following cleavage of alpha- and beta-tubulin C termini, under mild conditions we observed that microtubule-related polymers were formed, and also that ring aggregates were abundant. These ring aggregates were clearly detected by turbidity and electron microscope studies under standard assembly conditions. It was found that removal of the C-terminal fragments of tubulin (phosphocellulose-tubulin or Weisenberg tubulin) markedly favored Mg2(+)-induced ring formation. Binding of GDP to the exchangeable nucleotide site of cleaved tubulin further enhanced ring formation. The cleaved tubulin-GDP ring aggregates could be classified into three types: aggregates without apparent order, bidimensionally ordered ring aggregates, and stacks of rings. Temperature had little effect on the formation of these ring aggregates; however, they were very sensitive to ionic strength.

From 1980 to 1984, computerized data on the sensitivity to the main antibiotics of 1991 strains isolated from clinical specimens were evaluated in relation to beta-lactam use and hospital activity in a unit of orthopedic surgery. No major variations were found in distribution of species throughout the study period, whereas sensitivity to antimicrobial agents changed. From 1980 to 1982, patients had postoperative prophylactic treatment with cephalosporin (cefazolin) for two days; during the same period, 59% of 557 Gram negative organisms were resistant to cefazolin and 31% of Staphylococci were resistant to methicillin (and to other antibiotics). In 1983 and 1984, cefazolin was replaced by intraoperative flash therapy with a penicillin-M (cloxacillin); concomitantly, sensitivity to cefazolin increased among Gram negative organisms (38% of 485 isolates were cefazolin-resistant; p less than 0.001) and Staphylococci (16% of 342 isolates were methicillin-resistant; p less than 0.001). Phage typing of S. aureus failed to disclose any epidemic outbreak. Since hospital activity remained the same throughout the period under study, it seems justified to correlate the increase in bacterial sensitivity observed to the decrease in use of cephalosporin, although other factors (microepidemic, isolation techniques) may be involved.