bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration of a surgical microscope with automated zoom lenses using an active optical tracker
Authors: García Jaime , Thoranaghatte Ramesh , Marti Gaetan , Zheng Guoyan , Caversaccio Marco , González Ballester Miguel A.
Published: February 2008

Background

In this paper, we present a new method for the calibration of a microscope and its registration using an active optical tracker.

Methods

Practically, both operations are done simultaneously by moving an active optical marker within the field of view of the two devices. The IR LEDs composing the marker are first segmented from the microscope images. By knowing their corresponding three‐dimensional (3D) position in the optical tracker reference system, it is possible to find the transformation matrix between the referential of the two devices. Registration and calibration parameters can be extracted directly from that transformation. In addition, since the zoom and focus can be modified by the surgeon during the operation, we propose a spline based method to update the camera model to the new setup.

Results

The proposed technique is currently being used in an augmented reality system for image‐guided surgery in the fields of ear, nose and throat (ENT) and craniomaxillofacial surgeries.

Conclusions

The results have proved to be accurate and the technique is a fast, dynamic and reliable way to calibrate and register the two devices in an OR environment. Copyright © 2008 John Wiley & Sons, Ltd.
Achieving sustainability in US fisheries: community engagement in co‐management
Authors: May Candace K.
Published: February 2008

The United States government is moving toward a co‐management model to fishery governance based on stakeholder engagement. As essential stakeholders, the participation of local fishermen and their communities is fundamental for the efficiency and effectiveness of regulations and the sustainability of the nation's fisheries. However, the emphasis on stakeholder engagement is a substantial barrier to local participation. The author situates this barrier in the overriding assumption of US fishery governance, which considers individuals the key local actors in resource management. Nonetheless, existing fishery governance frameworks have produced intriguing alternative policy instruments. One such alternative, Community Development Quotas, may serve as a platform for the empowerment of local communities and, as a result, the encouragement of sustainable fishing and development in coastal areas. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Generating input data structures for automated program testing
Authors: Chung Insang , Bieman James M.
Published: February 2008

Automatic test data generation usually concerns identifying input values that cause a selected path to execute. If a given path involves pointers, then input values may be represented in terms of two‐dimensional dynamic data structures such as lists or trees. Thus, it is very important to identify the shape of the input data structure describing how many nodes are required and how nodes are connected each other. The approach presented in this paper makes use of the points‐to information for each statement in the selected path for the shape generation. It also converts each statement into a static single assignment (SSA) form without pointer dereferences. The SSA form serves as a system of constraints to be solved to yield input values for non‐pointer types. An empirical evaluation shows that shape generation can be achieved in linear time in terms of the number of pointer dereference operations. Copyright © 2008 John Wiley & Sons, Ltd.
Faecal incontinence in adults: NICE guideline
Authors: Ismail Sharif I.M.F.
Published: February 2008

The NICE guideline on the management of faecal incontinence calls for healthcare professionals to ask people in high‐risk groups, such as the frail and elderly, and women who have recently given birth, about whether they have any symptoms of the condition. In this article, Dr Ismail highlights the main features of this guideline, exploring how it could be implemented in primary care, and provides a simplified care algorithm of patient assessment and management. Copyright © 2008 Wiley Interface Ltd.
Managing the newly diagnosed HIV‐infected individual
Authors: Ferrand R.A. , Abbas A. , Kell P.D.
Published: February 2008

Recent advances in the treatment of HIV infection have led to prolonged survival and an emphasis on the long‐term clinical management of HIV disease. In this article, the authors discuss the assessment of a patient who is newly diagnosed with HIV infection. The initial assessment provides the opportunity to begin a partnership between the doctor and the patient that may continue for many years. Copyright © 2008 Wiley Interface Ltd.
Inter‐annual variations of leaf‐fall phenology and leaf‐litter nitrogen concentration in a hinoki cypress (Chamaecyparis obtusa Endlicher) stand
Authors: Inagaki Yoshiyuki , Sakai Atsushi , Kuramoto Shigeo , Kodani Eiji , Yamada Tsuyoshi , Kawasaki Tatsuro
Published: February 2008

Inter‐annual variations in leaf‐fall phenology and leaf‐litter nitrogen concentration were investigated for 13 years in a coniferous plantation of hinoki cypress trees (Chamaecyparis obtusa Endlicher) in Kochi, southern Japan. Mean annual nitrogen concentration in the leaf litter ranged from 5.97 to 7.12 g kg−1. The removal of 30 percent of the trees’ basal area in the 3rd year had little effect on leaf‐litter nitrogen concentration. The nitrogen concentration in the leaf litter was not correlated with the mean temperature from March to October. The leaf‐fall duration, i.e., time between 10 and 90% of the annual leaf fall, was shorter and the leaf‐litter nitrogen concentration was lower when the solar radiation from March to October was higher. The results suggest that the hinoki trees shed their leaves abruptly and have lower leaf‐litter nitrogen concentration when the solar radiation is higher and that effects of temperature on leaf‐fall properties may not be strong in warm climate areas.
Vision-centrality and the reflexive-identity of external object
Authors: Zhenming ZHAI
Published: February 2008

The correspondence of a sensory object to the category of a descriptive statement requires a reflexive-identity of the object, and such a reflexive-identity is primarily based on the cognition of spatiality. Spatiality is, however, constituted through visual perception. There are only two occasions on which definitive reflexive-identity is exemplified: the infinitesimal point and the infinite “One,” and others are just human stipulations that meet pragmatic needs of rough identification of things at hand. However, if a spatial point is not different from any so-called “other” spatial point, to validate the reflexive identity of any spatial point implies a validation of the reflexive identity of all spatial points. Thus, as “one” and “many” here become absolutely unitary, the infinitely small and the infinitely immense are identical.
Skeletal features of primary hyperoxaluria type 1, revisited
Authors: El Hage Samer , Ghanem Ismat , Baradhi André , Mourani Chebel , Mallat Samir , Dagher Fernand , Kharrat Khalil
Published: February 2008

Purpose

The purpose of this study was to describe the skeletal manifestations of primary hyperoxaluria type 1 (PH1), the most common of the primary hyperoxalurias.

Methods

We clinically and radiographically reviewed 12 consecutive patients diagnosed with PH1, aged between 2 and 17 years. All patients had evidence of some type of renal involvement, 4 of whom were at end-stage renal disease (ESRD) and were under dialysis.

Results

The main symptom was skeletal pain and was present only in the 4 severely involved patients and appeared during the second year of dialysis. The 2 most severely involved patients had evidence of pathological fractures. Radiological signs were present in patients with or without symptoms. These radiological signs were of two distinct types: those almost specific of oxalosis, such as dense and radiolucent metaphyseal bands and vertebral osteocondensations, which are found mainly in the severely involved individuals, and those less specific, such as signs of renal osteodystrophy, which are also found in less severely involved patients. Interestingly, our study revealed the presence of spondylolysis in 25% of cases. This latter finding is unique and has not previously been reported in the literature.

Conclusions

The skeletal manifestations of PH1 include specific and less specific radiological signs, with some patients being asymptomatic, and others presenting with bone pain and pathological fractures, as well as spondylolysis.
Heart failure with preserved ejection fraction: Clinical characteristics of 4133 patients enrolled in the I‐PRESERVE trial
Authors: McMurray John J.V. , Carson Peter E. , Komajda Michel , McKelvie Robert , Zile Michael R. , Ptaszynska Agata , Staiger Christoph , Donovan J. Mark , Massie Barry M.
Published: February 2008

Background:

We describe the baseline characteristics of subjects randomised in the largest placebo‐controlled, morbidity‐mortality trial to date in patients with heart failure and preserved ejection fraction — the irbesartan in heart failure with preserved systolic function trial (I‐PRESERVE).

Methods and results:

4133 patients with a mean age of 72 years (a third were 75 years or older) were randomised and 60% were women. The mean (SD) LVEF was 59 (9)% and almost 80% of patients were in NYHA Class III or IV. Approximately 80% of patients were also overweight or obese. Heart failure was reported by investigators to have a hypertensive aetiology in 64% of patients. Prior myocardial infarction was relatively uncommon (24%), as was coronary revascularisation (13%). Atrial fibrillation and diabetes each occurred in between a quarter and a third of patients. The following treatments were used at baseline: diuretic 83%, beta‐blocker 59%, calcium channel blocker 40%, ACE inhibitor 25%, spironolactone 15% and digoxin 14%.

Conclusions:

Patients in I‐PRESERVE are broadly representative of those seen in epidemiological studies and, because of this, the results of this trial should be generally applicable to “real world” patients with heart failure and preserved ejection fraction.
Quantitative analysis of apoptotic markers in human end‐stage heart failure
Authors: Bott‐Flügel Lorenz , Weig Hans‐Jörg , Ühlein Heiko , Nabauer Michael , Laugwitz Karl‐Ludwig , Seyfarth Melchior
Published: February 2008

Apoptosis – programmed cell death – has been implicated in a variety of cardiac diseases, including myocardial infarction and chronic heart failure. This study was conducted to quantify the amount of apoptotic markers in human end‐stage heart failure and to correlate the results to clinical parameters of heart failure.

Myocardial samples from 44 patients with end‐stage heart failure and 5 controls were collected at the time of heart transplantation. Lysates of tissue samples were analysed for cleavage of alpha actin, alpha actinin, troponin T, tropomyosin, essential myosin light chain‐1 (MLC‐1v), and gelsolin. We observed cleavage of alpha actin, and alpha actinin. Troponin I, tropomyosin, and MLC‐1v were not detectably cleaved. The amount of active caspase‐3 was low in all samples (1.10±0.1 ng/ml). The same applied for DNA histone fragments (0.61±0.04). In patients with acutely decompensated heart failure we observed a striking increase in caspase‐3 activity, but not DNA fragmentation. When calculated for the entire group there was no correlation between caspase‐3 activity, DNA fragmentation and haemodynamic or echocardiographic variables. Relevant increases in apoptosis were only observed in patients with acute decompensated heart failure.
Overview of emerging pharmacologic agents for acute heart failure syndromes
Authors: De Luca Leonardo , Mebazaa Alexandre , Filippatos Gerasimos , Parissis John T. , Böhm Michael , Voors Adriaan A. , Nieminen Markku , Zannad Faiez , Rhodes Andrew , El‐Banayosy Ali , Dickstein Kenneth , Gheorghiade Mihai
Published: February 2008

Background:

Several therapies commonly used for the treatment of acute heart failure syndromes (AHFS) present some well‐known limitations and have been associated with an early increase in the risk of death. There is, therefore, an unmet need for new pharmacologic agents for the early management of AHFS that may improve both short‐ and long‐term outcomes.

Aim:

To review the recent evidence on emerging pharmacologic therapies in AHFS.

Methods:

A systematic search of peer‐reviewed publications was performed on MEDLINE, EMBASE and Clinical Trials.gov from January 1990 to August 2007. The results of unpublished or ongoing trials were obtained from presentations at national and international meetings and pharmaceutical industry releases. Bibliographies from these references were also reviewed, as were additional articles identified by content experts.

Results:

Cumulative data from large studies and randomised trials suggest that therapies with innovative mechanisms of action may safely and effectively reduce pulmonary congestion or improve cardiac performance in AHFS patients.

Conclusion:

Some investigational agents for the management of AHFS are able to improve haemodynamics and/or clinical status. In spite of these promising findings, no new agent has demonstrated a clear benefit in terms of long‐term clinical outcomes compared to placebo or conventional therapies.
Hyponatraemia in acute heart failure is a marker of increased mortality but not when associated with hyperglycaemia
Authors: Milo‐Cotter Olga , Cotter Gad , Weatherley Beth D. , Adams Kirkwood F. , Kaluski Edo , Uriel Nir , O'Connor Christopher M. , Felker G. Michael
Published: February 2008

Previous studies suggest that hyponatraemia is a marker of neurohormonal activation and increased mortality in patients with acute heart failure (AHF). Although diabetes is a common co‐morbidity in heart failure, no prior study has considered the impact of serum glucose on this relationship.

Methods:

Over four consecutive months we prospectively registered all patients admitted due to AHF. Sodium and glucose levels were determined immediately upon admission. Patients were followed through admission and for the next 6 months. Of 342 patients enrolled, complete data were available for 331 patients.

Results:

Hyponatraemia (sodium <135 mmol/L) was detected in 22% of patients. However, 47% of patients with hyponatraemia had concomitant hyperglycaemia (glucose level <11 mmol/L). Hyponatraemia was associated with increased 6‐month mortality (21 vs. 8%, p=0.002). This association was restricted to patients who had hyponatraemia without concomitant hyperglycaemia. The 6‐month mortality of patients with and without hyponatraemia was 11% versus 10% (p=0.87) when hyperglycaemia was present versus 29% and 7% (p=0.001) when hyperglycaemia was absent.

Conclusions:

In this preliminary study, hyperglycaemia‐associated hyponatraemia was present in a significant proportion of patients admitted with AHF. In patients with hyperglycaemia, hyponatraemia had no prognostic significance, whereas in patients without hyperglycaemia, hyponatraemia remained a powerful predictor of mortality. These results need confirmation in a larger study.
Apolipoprotein M associates to lipoproteins through its retained signal peptide
Authors: Axler Olof , Ahnström Josefin , Dahlbäck Björn
Published: February 2008

Apolipoprotein M (apoM) is predominantly associated with HDL. In this study, it was investigated whether apoM's uncleaved signal peptide is necessary for the protein's ability to associate with lipoproteins. ApoM with a cleavable signal peptide, Q22A, was expressed, together with wild‐type apoM, in HEK293 cells. On size‐exclusion chromatography, the elution profile of wild‐type apoM was similar to that of human HDL‐associated plasma apoM. In contrast, the size of the Q22A mutant corresponded to free, unassociated apoM. This strongly indicates that the signal peptide is indeed necessary for apoM's ability to associate with lipid.
Increasing the noninvasive management of rhesus isoimmunization
Authors: Papantoniou Nikolaos , Daskalakis George , Anastasakis Eleftherios , Marinopoulos Spyros , Mesogitis Spyros , Antsaklis Aris
Published: February 2008

Objective

To determine the clinical outcome of isoimmunized pregnancies managed by middle cerebral artery peak systolic velocity (MCA‐PSV) in an intention‐to‐treat study.

Method

Rhesus isoimmunized pregnancies were managed with serial ultrasound and Doppler studies at 7‐day intervals up to 34 weeks of gestation, between 2001 and 2005. Invasive diagnostic and therapeutic procedures were carried out when MCA‐PSV was indicative of moderate or severe anemia.

Results

The overall sensitivity in detecting moderate to severe fetal anemia at less than 34 weeks was 100% (95% confidence interval, 54.1–100.0 L). Twenty‐two cases were managed with MCA‐PSV. Twelve cases needed fetal blood sampling and 6 cases needed intrauterine transfusion. Cordocentesis revealed a hematocrit of more than 26% in 6 fetuses.

Conclusion

Management by MCA‐PSV Doppler at weekly intervals is a highly sensitive method for detecting fetal anemia. It reduces the number of fetal blood samples needed and significantly lowers interventional procedures.
Cis-9,trans-11-conjugated linoleic acid but not its precursortrans-vaccenic acid attenuate inflammatory markers in the human colonic epithelial cell line Caco-2
Authors: Reynolds Clare M. , Loscher Christine E. , Moloney Aidan P. , Roche Helen M.
Published: February 2008

Trans-vaccenic acid (TVA) is a naturaltransfatty acid found in ruminant food produce. It is converted to thecis-9,trans-11 isomer of conjugated linoleic acid (c9, t11-CLA) by the action of stearoyl-CoA desaturase (SCD) in tissue. c9, t11-CLA has been associated with anti-inflammatory effects and also affects lipid metabolism. The aim of the present study was to determine if TVA is bioconverted to c9, t11-CLA in intestinal epithelial cells and to ascertain whether TVA has effects similar to c9, t11-CLA on markers of inflammation relevant to inflammatory bowel disease. The present study demonstrated that TVA treatment led to significant bioconversion into c9, t11-CLA in Caco-2 cells. Treatment with both TVA and c9, t11-CLA resulted in alteration of cellular fatty acid profile and SCD activity in the Caco-2 cell line. However, CLA, but not TVA, significantly modulated transcription of TNF-α, IL-12, IL-6 and production of IL-12 by these cells. Thus the present study established that TVA treatment can alter SCD desaturation indices and induce compositional changes in the fatty acid profile of the Caco-2 cell model of the human intestinal epithelium but this is not associated with functional effects on markers of the inflammatory response.
Children's Eating Behaviour Questionnaire: associations with BMI in Portuguese children
Authors: Viana V. , Sinde S. , Saxton J. C.
Published: February 2008

The objective of this study was to examine the association between the scores of the Children's Eating Behaviour Questionnaire (CEBQ) and BMI in a sample of Portuguese children. Using a cross-sectional design, a sample of 240 children (123 females and 117 males) aged 3–13 years were recruited from clinic and community-based settings. Parents completed the CEBQ to indicate their child's eating style for three ‘food approach’ and four ‘food avoidant’ sub-scales. Factor analyses revealed an underlying structure similar to the original CEBQ. Children's height and weight were measured to calculate BMI and Centre for Disease Control BMI z-scores. Hierarchical regression analyses controlling for gender, age and socioeconomic status indicated that all CEBQ sub-scales were significantly associated with BMI z-scores (P = 0·03 to < 0·001). Food approach scales were positively related to BMI z-scores (β = 0·33–0·51) and food avoidance negatively related (β = − 0·17 to − 0·46). Our results support the use of the CEBQ to further understand eating style as a behavioural pathway to obesity.
Association between consumption of black tea and iron status in adult Africans in the North West Province: the THUSA study
Authors: Hogenkamp P. S. , Jerling J. C. , Hoekstra T. , Melse-Boonstra A. , MacIntyre U. E.
Published: February 2008

The association between black tea consumption and iron status was investigated in a sample of African adults participating in the cross-sectional THUSA (Transition and Health during Urbanization of South Africans) study in the North West Province, South Africa. Data were analysed from 1605 apparently healthy adults aged 15–65 years by demographic and FFQ, anthropometric measurements and biochemical analyses. The main outcome measures were Hb and serum ferritin concentrations. No associations were seen between black tea consumption and concentrations of serum ferritin (menP = 0·059; womenP = 0·49) or Hb (menP = 0·33; womenP = 0·49). Logistic regression showed that tea consumption did not significantly increase risk for iron deficiency (men: OR 1·36; 95 % CI 0·99, 1·87; women: OR 0·98; 95 % CI 0·84, 1·13) nor for iron deficiency anaemia (men: OR 1·28; 95 % CI 0·84, 1·96; women: OR 0·93; 95 % CI 0·78, 1·11). Prevalence of iron deficiency and iron deficiency anaemia was especially high in women: 21·6 and 14·6 %, respectively. However, the likelihood of iron deficiency and iron deficiency anaemia was not significantly explained by tea consumption in sub-populations which were assumed to be at risk for iron deficiency. Regression of serum ferritin levels on tea consumption in women ≤ 40 years, adults with a daily iron intake ≤ 5·80 mg and adults with ferritin levels ≤ 26·60 μg/l, respectively, showedPvalues in the range of 0·28–0·88. Our findings demonstrate that iron deficiency and iron deficiency anaemia is not significantly explained by black tea consumption in a black adult population in South Africa. Tea intake was also not shown to be related to iron status in several sub-populations at risk for iron deficiency.
Prospective study on food fortification with vitamin D among adolescent females in Finland: minor effects
Authors: Lehtonen-Veromaa Marjo , Möttönen Timo , Leino Aila , Heinonen Olli J. , Rautava Essi , Viikari Jorma
Published: February 2008

Vitamin D insufficiency is common particularly during wintertime. After the recommendation by the Ministry of Social Affairs and Health, Finnish fluid milks and margarines have been fortified with vitamin D since February 2003. The aims of the present study were to examine the impact of vitamin D fortification of food supplies on serum 25-hydroxyvitamin D (S-25(OH)D) concentrations and on daily dietary vitamin D intake among adolescent females. One hundred and forty-two girls of Caucasian ethnicity aged 12–18 years completed semi-quantitative FFQ from which the dietary vitamin D and Ca intakes were calculated. S-25(OH)D was measured by radioimmunoassay. The study was performed from February–March 2000 to February–March 2004, one year after the initiation of fortification. The mean dietary intake of vitamin D was < 7·5 μg in 91·5 % of the adolescent girls in 2000 and 83·8 % in 2004. The midwinter mean S-25(OH)D concentration did not change significantly during the follow-up period (48·3 v. 48·1 nmol/l, NS). The proportion of participants who had S-25(OH)D concentration < 50 nmol/l was 60·6 % in 2000 and 65·5 % in 2004. Only 7·0 % of the participants had an adequate S-25(OH)D ( ≥ 75 nmol/l) level in 2000 or 4 years later. The vitamin D fortification of fluid milks and margarines was inadequate to prevent vitamin D insufficiency. There are numerous adolescent girls and women who are not reached by the current fortification policy. Therefore new innovative and feasible ways of improving vitamin D nutrition are urged.
Influence of shell size ofLymnaea columellaon infectivity and development ofFasciola hepatica
Authors: Coelho L.H.L. , Guimarães M.P. , Lima W.S.
Published: February 2008

Experimental infections ofLymnaea columellawithFasciola hepaticawere carried out to determine the influence of shell size on the infection rate and on the outcome of rediae and cercariae. Snails were divided into seven groups according to shell size: 2–4 mm, 5–6 mm, 7–8 mm, 9–10 mm, 11–12 mm, 13–14 mm and 15 mm or more. One hundred snails in each group were infected by using four miracidia for each snail. Snails with larger shell size showed a lower infection rate, the groups presenting the highest (79%) and lowest (2%) proportions of positives being those of 5–6 mm and 15 mm or more, respectively. Cercariae were present in 21% of them at 31 days post-infection, and cercarial shedding was observed 61 days post-infection. It was concluded that there is a non-linear negative association between shell size and infection rate.
The role of fear and anxiety in the familial risk for major depression: a three-generation study
Authors: Warner V. , Wickramaratne P. , Weissman M. M.
Published: February 2008

Background

The overlap between anxiety and major depressive disorder (MDD), the increased risk for depression and anxiety in offspring of depressed parents, the sequence of onset with anxiety preceding MDD, and anxiety as a predictor of depression are well established. The specificity of anxiety disorders in these relationships is unclear. This study, using a longitudinal high-risk design, examined whether anxiety disorders associated with the emotions fear and anxiety mediate the association between parental and offspring depression.

Method

Two hundred and twenty-four second-generation and 155 third-generation descendants at high and low risk for depression because of MDD in the first generation were interviewed over 20 years. Probit and Cox proportional hazard models were fitted with generation 2 (G2) or G3 depression as the outcome and parental MDD as the predictor. In G2 and G3, fear- (phobia or panic) and anxiety-related [overanxious or generalized anxiety disorder (GAD)] disorders were examined as potential mediators of increased risk for offspring depression, due to parental MDD.

Results

In G2, fear-related disorders met criteria for mediating the association between parental MDD and offspring MDD whereas anxiety-related disorders did not. These results were consistent, regardless of the analytic methods used. Further investigation of the mediating effect of fear-related disorders by age of onset of offspring MDD suggests that the mediating effect occurs primarily in adolescent onset MDD. The results for G3 appear to follow similar patterns.

Conclusions

These findings support the separation of anxiety disorders into at least two distinct forms, particularly when examining their role in the etiology of depression.
Scenarios of diffusion and control of an influenza pandemic in Italy
Authors: RIZZO C. , LUNELLI A. , PUGLIESE A. , BELLA A. , MANFREDI P. , TOMBA G. SCALIA , IANNELLI M. , DEGLI ATTI M. L. CIOFI
Published: February 2008

To predict the spread of a pandemic strain of influenza virus in Italy and the impact of control measures, we developed a susceptible–exposed, but not yet infectious–infectious–recovered, and no longer susceptible (SEIR) deterministic model with a stochastic simulation component. We modelled the impact of control measures such as vaccination, antiviral prophylaxis and social distancing measures. In the absence of control measures, the epidemic peak would be reached about 4 months after the importation of the first cases in Italy, and the epidemic would last about 7 months. When combined, the control measures would reduce the cumulative attack rate to about 4·2%, at best, although this would require an extremely high number of treated individuals. In accordance with international findings, our results highlight the need to respond to a pandemic with a combination of control measures.
Red Halos of Galaxies – Reservoirs of Baryonic Dark Matter?
Authors: Zackrisson E. , Bergvall N. , Flynn C. , Östlin G. , Micheva G. , Caldwell B.
Published: February 2008

Deep optical/near-IR surface photometry of galaxies outside the Local Group have revealed faint and very red halos around objects as diverse as disk galaxies and starbursting dwarf galaxies. The colours of these structures are too extreme to be reconciled with stellar populations similar to those seen in the stellar halos of the Milky Way or M31, and alternative explanations like dust reddening, high metallicities or nebular emission are also disfavoured. A stellar population obeying an extremely bottom-heavy initial mass function (IMF), is on the other hand consistent with all available data. Because of its high mass-to-light ratio, such a population would effectively behave as baryonic dark matter and could account for some of the baryons still missing in the low-redshift Universe. Here, we give an overview of current red halo detections, alternative explanations for the origin of the red colours and ongoing searches for red halos around types of galaxies for which this phenomenon has not yet been reported. A number of potential tests of the bottom-heavy IMF hypothesis are also discussed.
Lost Baryons at Low Redshift
Authors: Mathur Smita , Nicastro Fabrizio , Willimas Rik
Published: February 2008

We review our attempts to discover lost baryons at low redshift with the “X-ray forest” of absorption lines from the warm-hot intergalactic medium. We discuss the best evidence to date along the Mrk 421 sightline. We then discuss the missing baryons in the Local Group and the significance of the z = 0 absorption systems in X-ray spectra. We argue that the debate over the Galactic vs. extragalactic origin of the z = 0 systems is premature as these systems likely contain both components. Observations with next generation X-ray missions such as Constellation-X and XEUS will be crucial to map out the warm-hot intergalactic medium.
Observed Properties of Dark Matter on Small Spatial Scales
Authors: Wyse Rosemary F.G. , Gilmore Gerard
Published: February 2008

The nature of dark matter is one of the outstanding questions of astrophysics. The internal motions of member stars reveal that the lowest luminosity galaxies in the Local Group are the most dark-matter dominated. New large datasets allow one to go further, and determine systematic properties of their dark matter haloes. We summarise recent results, emphasising the critical role of the dwarf spheroidal galaxies in understanding both dark matter and baryonic processes that shape galaxy evolution.
Connecting Lost Baryons and Dark Galaxies via QSO Absorption Lines
Authors: Tripp Todd M.
Published: February 2008

QSO absorption lines are sensitive to very low density gas, and consequently, QSO spectroscopy provides a powerful tool for measuring the distribution, physical conditions, and metal enrichment of baryons in the intergalactic medium and in “dark galaxies”. However, ultraviolet spectroscopy is required to study QSO absorbers in the nearby universe where the connections between the absorbing gas and galaxies/environment can be probed. This talk reviewed several recent studies of low-zQSO absorbers in order to demonstrate the value of combining high-resolution ultraviolet spectroscopy with complementary information on the absorber environment, e.g., mapping of 21 cm emission in the vicinity of the absorbers; some notes on these examples are presented in this paper. The absorbers probed range from high-N(H I) damped Lyman α absorbers down to very low-column Lyα forest clouds with logN(H I) < 13.5. The high-N(H I) systems are candidate “dark galaxies” – these systems are more metal enriched than the high-zIGM, possibly due to in-situ star formation, and some of the absorbers are highly metal enriched. However, we have obtained follow-up 21cm emission mapping with the VLA and deep optical imaging, and while we do find H I clouds associated with the absorbers in 21cm emission, we often do not find any evidence of in-situ stars. At this juncture, it seems more likely that these low-zabsorbers were enriched with metals within galaxies and were subsequently transported out into the IGM, e.g., by tidal stripping or galactic winds. This contribution also summarizes some recent results on the search for lost baryons in the “warm-hot” (shock-heated) low-redshift IGM.
ALFALFA: HI Cosmology in the Local Universe
Authors: Giovanelli Riccardo
Published: February 2008

For the last 25 years, the 21 cm line has been used productively to investigate the large–scale structure of the Universe, its peculiar velocity field and the measurement of cosmic parameters. In February 2005 a blind HI survey that will cover 7074 square degrees of the high latitude sky was started at Arecibo, using the 7-beam feed L-band feed array (ALFA). Known as the Arecibo Legacy Fast ALFA (ALFALFA) Survey, the program is producing a census of HI-bearing objects over a cosmologically significant volume of the local Universe. With respect to previous blind HI surveys, ALFALFA offers an improvement of about one order of magnitude in sensitivity, 4 times the angular resolution, 3 times the spectral resolution, and 1.6 times the total bandwidth of HIPASS. ALFALFA can detect 7×104D2M⊙of HI, whereDis the source distance in Mpc. As of mid 2007, 44% of the survey observations and 15% of the source extraction are completed. We discuss the status of the survey and present a few preliminary results, in particular with reference to the proposed “dark galaxy” VirgoHI21.
Cosmic Variance in the HI Mass Function
Authors: Schneider Stephen E.
Published: February 2008

I review the history of blind HI surveys and the evidence for cosmic variance in the HI mass function. Even the most sensitive current surveys are challenged by noise levels that make determining the shape of the mass function difficult, and this can lead to discrepant results. However, some differences in the mass function appear to be real environmental effects, and this suggest that there are locales where dark (or dim) HI-rich galaxies are more likely to be found. The requirements for significantly deeper surveys beyond the local supercluster to sample cosmic variance in a wider variety of environoments are modeled and discussed.
The Arecibo Galaxy Environment Survey – Potential for finding Dark Galaxies and Results so far
Authors: Minchin R. F. , Auld R. , Cortese L. , Davies J. I. , Momjian E. , Taylor R. , Catinella B. , Henning P. , Linder S. , Muller E. , O'Neil K. , Rosenberg J. , Sabatini S. , Schneider S. E. , Stage M. , van Driel W. ,   the AGES team
Published: February 2008

The Arecibo Galaxy Environment Survey is a blind neutral hydrogen survey using the ALFA multibeam receiver at Arecibo Observatory to reach unprecedented sensitivities in a number of selected fields in the local Universe. When completed the survey will cover 200 square degrees out to a distance of at least 270 Mpc. If a population of gas-rich dark galaxies exists, then this survey is in a prime position to uncover that population.

So far 20 square degrees have been covered in the regions of Abell 1367, the Virgo Cluster, the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156. Over 200 sources have been found, including a number that have no obvious optical counterparts. We discuss here the potential of AGES for uncovering more such objects and the characteristics of the dark sources identified to date.
Free–Floating HI Clouds in the M 81 Group
Authors: Brinks Elias , Walter Fabian , Skillman Evan D.
Published: February 2008

Recent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~ 105 M⊙) HI clouds with no obvious optical counterparts. We have searched 10 fields in the M 81 group totalling 2.2 square degree, both targeting known dwarf spheroidal galaxies and blank fields around the central triplet. Our observations show that the new population of low–mass HI clouds appears to be confined to a region toward the south–east of the central triplet (at distances of ~ 100 kpc from M 81). Possible explanations for these free–floating HI clouds are that they are related to the dSphs found to the South–East of M 81, that they belong to the galaxies of the M 81 triplet (equivalent to HVCs), that they are of primordial nature and provide fresh, unenriched material falling into the M 81 group, or that they are tidal debris from the 3–body interaction involving M 81–M 82–NGC 3077. Based on circumstantial evidence, we currently favour the latter explanation.
The Halo by Halo Missing Baryon Problem
Authors: McGaugh Stacy S.
Published: February 2008

The global missing baryon problem – that the sum of observed baryons falls short of the number expected form BBN – is well known. In addition to this, there is also a local missing baryon problem that applies to individual dark matter halos. This halo by halo missing baryon problem is such that the observed mass fraction of baryons in individual galaxies falls short of the cosmic baryon fraction. This deficit is a strong function of circular velocity. I give an empirical estimate of this function, and note the presence of a critical scale of ~ 900 km s−1 therein. I also briefly review Ωb from BBN, highlighting the persistent tension between lithium and the CMB, and discuss some pros and cons of individual galaxies and clusters of galaxies as potential reservoirs of dark baryons.
The Local Void is Really Empty
Authors: Tully R. Brent
Published: February 2008

Are voids in the distribution of galaxies only places with reduced matter density and low star formation efficiency or are they empty of matter? There is now compelling evidence of expansion away from the Local Void at very high velocities. The motion is most reasonably interpreted as an evacuation of the void, which requires that the void be very large and very empty.
Dim Baryons in the Cosmic Web
Authors: Impey Chris D.
Published: February 2008

The distribution of baryons beyond galaxies is descibed. The majority of the baryons, which represent 4% of the cosmic mass and energy budget, lie far from individual galaxies in the diffuse intergalactic medium (IGM). Many of these baryons are in a warm phase that can be probed by quasar absorption in the Lyman-α line of hydrogen. The mature field of quasar spectroscopy can diagnose the location, physical state, metallicity, and general geometry of this gas, which is called the “cosmic web.” The remainder of the gas is kept very hot by infall and shocks and is mostly in higher density regions such as filaments, groups and clusters. The hot gas is only detectable via X-rays and the absorption of highly ionized species of heavy elements. The baryons in low density regions of space are excellent tracers of underlying dark matter. The evolution of the cosmic web indicates where to look for the baryons in collapsed objects but the overall inefficiency of galaxy formation has conspired to keep most baryons dark.
A Census of Baryons in Galaxy Clusters and Groups
Authors: Gonzalez Anthony H. , Zaritsky Dennis , Zabludoff Ann I.
Published: February 2008

While the baryon fraction in galaxy groups and clusters may be expected to reflect the universal value, observations of cluster baryon fractions have generally fallen short of this expectation and indicated a possible correlation with cluster mass. We present a new determination of the total baryon budget in nearby galaxy groups and clusters that includes the contributions from stars in galaxies, intracluster stars, and the intracluster medium. We find that the baryon mass fraction within r500 is independent of system mass and lower than the WMAP value. We conclude however that the present shortfall provides no compelling evidence for additional missing baryons, since it may arise due to a theoretically predicted deficit of baryons within r500 and systematic uncertainties associated with the mass determinations. With the addition of the ICL to the stellar mass in galaxies, the increase in X-ray gas mass fraction with increasing total mass is entirely accounted for by a decrease in the total stellar mass fraction, supporting the argument that the behavior of both the stellar and X-ray gas components is dominated by a decrease in star formation efficiency in more massive environments. Within just the stellar component, the fraction of the total stellar luminosity in the central, giant brightest cluster galaxy (BCG) and ICL (hereafter the BCG+ICL component) decreases as velocity dispersion (σ) increases, suggesting that ICL may grow less efficiently in higher mass environments. The identification of low mass groups with large BCG+ICL components also demonstrates that the massive cluster environment is not required to form intracluster stars. These proceedings are a condensed version of the work presented in Gonzalez, Zaritsky & Zabludoff (2007), and we refer the reader to that paper for a more complete discussion.
Statistical Properties of the IntraCluster Light from SDSS Image Stacking
Authors: Zibetti Stefano
Published: February 2008

The presence of a diffuse stellar component in galaxy clusters has been established by a number of observational works in recent years. In this contribution I summarize our results (Zibettiet al. 2005) obtained by stacking SDSS images of 683 clusters, selected with the maxBCG algorithm at 0.2 <z< 0.3. Thanks to our large sample (≳30 times larger than any other sample of individually observed clusters so far) and the advantages of image stacking applied to SDSS images, we are able to measure thesystematicproperties of the intracluster light (ICL) with very high accuracy.

We find that the average surface brightness of the ICL ranges between 26 and 32 mag arcsec−2, and constantly declines from 70 kpc cluster-centric distance (i.e. distance from the BCG) to 700 kpc. Interestingly, thefractionof diffuse light over the total light (including galaxies), monotonically declines from ~ 50 to ≲ 5% over the same range of distances, thus showing that the ICL is more easily produced close to the bottom of a cluster's potential well. On the other hand, clusters lacking a bright BCG, hardly build up a large amount of intracluster stellar component. The link between the growth of the BCG and the ICL is also suggested by the strong degree of alignment between these two components which is observed in clusters where the BCG displays a significant elongation. With the additional fact that the colors of the ICL are consistent with those of galaxies, all this appears to be evidence for intracluster stars being stripped from galaxies that suffer very strong tidal interactions in the center of clusters and eventually merge into the BCG.

Our measurements also show that intracluster stars are a minor component of a cluster's baryonic budget, representing only ~ 10% of the total optical emission within 500 kpc.

Finally, we discuss some open issues that emerge from a comparison of the present results with other observations and recent theoretical modeling.
Star Formation Thresholds
Authors: Schaye Joop
Published: February 2008

To make predictions for the existence of “dark galaxies”, it is necessary to understand what determines whether a gas cloud will form stars. Star formation thresholds are generally explained in terms of the Toomre criterion for gravitational instability. I contrast this theory with the thermo-gravitational instability hypothesis of Schaye (2004), in which star formation is triggered by the formation of a cold gas phase and which predicts a nearly constant surface density threshold. I argue that although the Toomre analysis is useful for the global stability of disc galaxies, it relies on assumptions that break down in the outer regions, where star formation thresholds are observed. The thermo-gravitational instability hypothesis can account for a number of observed phenomena, some of which were thought to be unrelated to star formation thresholds.
Too Small to Form a Galaxy: How the UV Background Determines the Baryon Fraction
Authors: Hoeft M. , Yepes G. , Gottlöber S.
Published: February 2008

The cosmic ultraviolet background (UVB) heats the intergalactic medium (IGM), as a result the gas in dark matter halos below a certain mass is too hot to cool within a Hubble time. The UVB effectively suppresses the formation of dwarf galaxies. Using high resolution cosmological hydrodynamical simulations we show that photo heating leads to small baryon fractions in halos below ~ 6× 109h−1M⊙, independent of the cosmic environment. The simulations are carried out assuming a homogeneous UVB with flux densities as given by Haardt, &, Madau (1996). A halo may stop to condense gas significantly after the universe is reionised, namely when its mass falls below the characteristic mass scale set by the photo heating. Assuming a spherical halo model we derive this characteristic mass analytically and identify the main mechanisms that prevent the gas from cooling in small halos. The theoretically derived characteristic mass is smaller than the one obtained from observations. Increasing the energy per ionising photon by a factor between four and eight would be sufficient to reconcile both. This is equivalent to an average temperature of the IGM of ~ 104K. In this sense the faint end of the luminosity function may serve as a calorimeter for the IGM.
Hunting for Ghosts: Low Surface Brightness Galaxies from Pixels
Authors: Scaramella Roberto , Sabatini Sabina
Published: February 2008

We outline an approach devoted to the detection of low surface brightness galaxies on astronomical images. We use a multi-scale approach, take into account sources of incompleteness and check selection functions both analytically and with simulations.
Baryonic Properties of the Darkest Galaxies
Authors: Grebel Eva K.
Published: February 2008

The faintest and darkest galaxies that we know of today are the dwarf spheroidal (dSph) galaxies. They appear to be plausible counterparts of cosmologically predicted small subhalos though their numbers do not (yet?) suffice to resolve the substructure crisis. Their mass-to-light ratios may go up to 1000 for the faintest objects, and their total masses are of the order of a few 106to 107M⊙. Though most dSphs are dominated by old populations, they all show extended and presumably slow star formation histories with considerable enrichment. While environment has certainly affected their evolution, as evidenced by the morphology-gas-distance relations, intrinsic properties such as their (initial) baryon content may also have played a major role. The complexity and diversity of their star formation histories is surprising, and there are no obvious evolutionary connections to dwarf irregulars.
The Dwarf Low Surface Brightness Population in Different Environments of the Local Universe
Authors: Sabatini S. , Davies J. I. , Roberts S. , Scaramella R.
Published: February 2008

The nature of the dwarf galaxy population as a function of location in the cluster and within different environments is investigated. We have previously described the results of a search for low surface brightness objects in data drawn from an East-West strip of the Virgo cluster (Sabatiniet al(2004)) and have compared this to a large area strip outside of the cluster (Robertset al(2004)). In this talk I compare the East-West data (sampling sub-cluster A and outward) to new data along a North-South cluster strip that samples a different region (part of sub-cluster A, and the N, M clouds) and with data obtained for the Ursa Major cluster and fields around the spiral galaxy M101. The sample of dwarf galaxies in different environments is obtained from uniform datasets that reach central surface brightness values of 26 B mag/arcsec2and an apparent B magnitude of 21 (MB=−10 for a Virgo Cluster distance of 16 Mpc). We discuss and interpret our results on the properties and distribution of dwarf low surface brightness galaxies in the context of variuos physical processes that are thought to act on galaxies as they form and evolve.