Miracle-dz/UniFAR-FTUs huggingface dataset:
Central Cross-Sections Make Surfaces of Revolution Quadric

The left side of this equation measures distance (squared) from the z-axis the axis of revolution while the right sets the vertical "profile" of the surface. Archimedes knew that any plane tilted sufficiently far from the axis of such a surface cuts it in an ellipse, and Fermât apparently realized the converse: elliptical crosssections make a surface of revolution quadric [2]. One can verify Fermat's observation using high-school algebra, but here we prove a far stronger statement: Cross-sections which are merely central (in the sense we shortly explain) make a surface of revolution quadric. This fact has generalizations and consequences, some of which we sketch in our concluding remarks, but we leave the full treatment of such extensions to a forthcoming article. Here we focus on the claim italicized above, and proceed now to define some terms we need to state and prove it. A C1 loop in R3 is the image of aperiodic C1 mapping R -+ R3 whose derivative never vanishes. We call a loop in R3 central if it has symmetry with respect to reflection through some point. We call that point its center and say that the loop is centered there. The center of a loop clearly coincides with the center of mass, so it is unique. Circles, ellipses, and many other loops have central symmetry, though of course most loops do not. For instance, no loop sufficiently close to a triangle is central. By a C1 surface of revolution, we mean a surface S definable, after a rigid motion, via
Imbalance of plasma membrane ion leak and pump relationship as a new aetiological basis of certain disease states

The basis for life is the ability of the cell to maintain ion gradients across biological membranes. Such gradients are created by specific membrane‐bound ion pumps [adenosine triphosphatases (ATPases)]. According to physicochemical rules passive forces equilibrate (dissipate) ion gradients. The cholesterol/phospholipid ratio of the membrane and the degree of saturation of phospholipid fatty acids are important factors for membrane molecular order and herewith a determinant of the degree of non‐specific membrane leakiness. Other operative principles, i.e. specific ion channels can be opened and closed according to mechanisms that are specific to the cell. Certain compounds called ionophores can be integrated in the plasma membrane and permit specific inorganic ions to pass. Irrespective of which mechanism ions leak across the plasma membrane the homeostasis may be kept by increasing ion pumping (ATPase activity) in an attempt to restore the physiological ion gradient. The energy source for this work seems to be glycolytically derived ATP formation. Thus an increase in ion pumping is reflected by increased ATP hydrolysis and rate of glycolysis. This can be measured as an accumulation of breakdown products of ATP and end‐products of anaerobic glycolysis (lactate). In certain disease entities, the balance between ATP formation and ion pumping may be disordered resulting in a decrease in inter alia (i.a.) cellular energy charge, and an increase in lactate formation and catabolites of adenylates. Cardiac syndrome X is proposed to be due to an excessive leakage of potassium ions, leading to electrocardiographic (ECG) changes, abnormal Tl‐scintigraphy of the heart and anginal pain (induced by adenosine). Cocksackie B3 infections, a common agent in myocarditis might also induce an ionophore‐like effect. Moreover, Alzheimer's disease is characterized by the formation of extracellular amyloid deposits in the brain of patients. Perturbation of cellular membranes by the amyloid peptide during the development of Alzheimer's disease is one of several mechanisms proposed to account for the toxicity of this peptide on neuronal membranes. We have studied the effects of the peptide and fragments thereof on 45Ca2+‐uptake in human erythrocytes and the energetic consequences. Treatment of erythrocytes with the β1−40 peptide, results in qualitatively similar nucleotide pattern and decrease of energy charge as the treatment with Ca2+‐ionophore A23187. Finally, in recent studies we have revealed and published in this journal that a rare condition, Tarui's disease or glycogenosis type VII, primarily associated with a defect M‐subunit of phosphofructokinase, demonstrates as a cophenomenon an increased leak of Ca2+ into erythrocytes.
A Stochastic Causality-Based Process Algebra

This paper discusses stochastic extensions of a simple process algebra in a causality-based setting. Atomic actions are supposed to happen after a delay that is determined by a stochastic variable with a certain distribution. A simple stochastic type of event structures is discussed, restricting the distribution functions to be exponential. A corresponding operational semantics of this model is given and compared to existing (interleaved) approaches. Secondly, a stochastic variant of event structures is discussed where distributions are of a much more general nature, viz. of phase-type. This includes exponential, Erlang, Coxian and mixtures of exponential distributions.
The importance of behavioural studies in conservation biology

The exciting research developments in animal behaviour over the last two decades have had a negligible impact on conservation. I list 20 subjects in which the study of animal behaviour can make a significant contribution to conservation. Behaviour may in itself be worth conserving. I also suggest how behavioural ecologists could become more involved in conservation. Copyright 1998 The Association for the Study of Animal Behaviour.
DeNASA: Destination-Naive AS-Awareness in Anonymous Communications

Abstract Prior approaches to AS-aware path selection in Tor do not consider node bandwidth or the other characteristics that Tor uses to ensure load balancing and quality of service. Further, since the AS path from the client’s exit to her destination can only be inferred once the destination is known, the prior approaches may have problems constructing circuits in advance, which is important for Tor performance. In this paper, we propose and evaluate DeNASA, a new approach to AS-aware path selection that is destination-naive, in that it does not need to know the client’s destination to pick paths, and that takes advantage of Tor’s circuit selection algorithm. To this end, we first identify the most probable ASes to be traversed by Tor streams. We call this set of ASes the Suspect AS list and find that it consists of eight highest ranking Tier 1 ASes. Then, we test the accuracy of Qiu and Gao AS-level path inference on identifying the presence of these ASes in the path, and we show that inference accuracy is 90%. We develop an AS-aware algorithm called DeNASA that uses Qiu and Gao inference to avoid Suspect ASes. DeNASA reduces Tor stream vulnerability by 74%. We also show that DeNASA has performance similar to Tor. Due to the destination-naive property, time to first byte (TTFB) is close to Tor’s, and due to leveraging Tor’s bandwidth-weighted relay selection, time to last byte (TTLB) is also similar to Tor’s.
Unemployment and underemployment in Kenya: a gender gap analysis

This paper analyses the gender gaps in open unemployment and underemployment in Kenya, using data from the Kenya Integrated Household Budget Survey 2005/06. Unemployment and underemployment probability functions were estimated separately for men and women, using binary probit specification and the gender gap in each outcome was decomposed to determine what factors explain it. The probit estimates indicate that even after controlling for differences in personal and household characteristics, the women were still more likely than men to be unemployed or underemployed. Observable individual human capital characteristics, marital status, region of residence, non-labour income and individual’s age were significant determinants of unemployment and underemployment. Decomposition results show that most (88.8percent) of the total female-male unemployment probability gap is explained by female-male differences in individual and household characteristics and only 11.2percent is unexplained. In contrast, only 5.4percent of the female-male underemployment probability gap is explained by female-male differences in individual and household characteristics while 94.6percent is unexplained. The key characteristics generating female-male gaps in unemployment and underemployment probabilities in Kenya are region of residence, age, education level, marital status and adverse shocks. This implies that policy interventions that aim to lower gender gaps in unemployment and underemployment should target the most affected age cohorts and locations. Policy should also give priority to interventions that narrow disparities in access to education and those that reduce adverse shocks.
The mechanism of T cell mediated cytotoxicity II. morphological studies of cell death by time-lapse microcinematography

The morphological changes in mastocytoma cell death by complement, T cell mediated cytotoxicity and in natural cell death as seen by time-lapse microcinematography are recorded. In complement lysis, progressive changes leading to a final swelling of the cell occur in the absence of cell membrane activity. This is in marked contrast to the T-cell lysis in which violent zeiosis (boiling) of the cytoplasm is a constant feature. Similar changes are seen in natural cell death and the possibility that a similar mechanism is involved in both cases is discussed. Analysis of the data showed that there was no fixed time relation between T cell contact and zeiosis. Target cells were sometimes killed rapidly after contact, but in some cases periods of up to 200 min were observed between contact and killing. After contact and up to the onset of zeiosis target cells retain normal morphology and movement, suggesting that contact itself does not damage the target cell. This is consistent with the data showing that the release of both small and large cytoplasmic markers have similar kinetics. An analysis of the relation between cell volume and time between T cell contact and zeiosis suggested that mastocytoma cells may be more susceptible to c. m. c. during G 1 phase. Studies with peritoneal exudate cells as target cells have allowed the morphological changes to be seen in a variety of other cell types. Macrophages rapidly retract to a spherical form immediately before zeiosis, indicating a change preceding zeiosis. The phase of zeiosis varies with different cell types.
Prenatal Cocaine Exposure and Prolonged Focus Attention

In experimental models, prenatal cocaine exposure has been found to perturb monoaminergic development of systems implicated in modulating attention. To determine whether prenatal cocaine exposure affects infant attention, we assessed visual recognition memory and focused attention during free play. We enrolled at birth 380 infants, 113 cocaine exposed, using multiple biomarkers to assess drug exposure. Behavior was videotaped and coded off-line for sustained looking time (i.e. focused attention), banging and intrusion. Prenatal cocaine exposure was not associated with visual recognition memory, but was significantly associated with longer sustained looking times (average focused attention) at ages 6 months (p = 0.02) and 12 months (p = 0.04) in analyses that adjusted for variables, including maternal intelligence, education, depressive scores and other exposures (alcohol, tobacco and marijuana). Cocaine-exposed infants at age 12 months also spent significantly less time in banging activity (p = 0.02) after adjusting for confounding variables. This finding was not explained through cocaine effects on motor development, neurological findings or time spent in focused attention. Prenatal cocaine exposure was significantly associated with longer periods of sustained looking or focused attention in infancy, a finding that could interpreted as a measure of poor processing efficiency, or alternatively as precocious maturation of attentional systems. Either interpretation has implications for later cognitive development. Lower banging activity among cocaine exposed was not explained through cocaine effects on motor development or neurological findings, suggesting that activity level itself is diminished in these infants. Whether focused attention findings impact long term development awaits further study.
Human Equilibrative Nucleoside Transporter-3 (hENT3) Spectrum Disorder Mutations Impair Nucleoside Transport, Protein Localization, and Stability*

Accumulating evidence reveals that sole mutations in hENT3 cause a spectrum of human genetic disorders. Among these include H syndrome, characterized by scleroderma, hyperpigmentation, hypertrichosis, hepatomegaly, cardiac abnormalities and musculoskeletal deformities, pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndrome, characterized by autoantibody-negative diabetes mellitus and skin deformities, familial Rosai-Dorfman disease, characterized by short stature, familial histiocytosis and sinus histiocytosis with massive lymphadenopathy (SHML), characterized by severe tissue infiltration of immune cells and swollen lymph nodes. hENT3 spectrum disorders share a common mutation and share overlapping clinical manifestations that display many intriguing resemblances to mitochondrial and lysosomal disorders. Although earlier studies identify hENT3 as a mitochondrial and a lysosomal nucleoside transporter, the precise connections between hENT3 and the pathophysiology of these disorders remain unresolved. In this study, we performed functional and biochemical characterization of these mutations in hENT3. We report severe reductions/losses of hENT3 nucleoside transport functions of hENT3 syndrome mutants. In addition to transport alterations, we provide evidence for possible loss of hENT3 functions in all H and pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndromes due to either mistrafficking or altered stability of mutant hENT3 proteins.
Comparison of the mouse foot pad test with a Buddemeyer type radiorespirometric assay in detecting viable Mycobacterium leprae in human lesional biopsies.

AIM This study assesses the utility of a Buddemeyer type radiorespirometric (RR) assay in detecting viable Mycobacterium leprae in clinical samples taking the mouse foot pad (MFP) test as gold standard. METHODS A total of 131 skin biopsy specimens comprising of 56 untreated, smear-positive, borderline lepromatous and lepromatous leprosy (BL-LL) and 75 untreated, smear-negative, borderline tuberculoid and mid-borderline (BT-BB) specimens were processed by both the methods. The cut-off value (in counts per minute, cpm) for test samples in the RR assay was determined using nonleprous (normal) skin biopsy specimens. RESULTS In the untreated BL-LL and BT-BB groups, 86 and 56% of the cases tested positive in the RR assay respectively, which was comparable to the results of the MFP test (80 and 45% respectively). The overall concordance between the two tests was 74.79%, whereas the sensitivity and specificity were 75 and 74.3% respectively. A Kappa value of 0.459 indicated a fairly good agreement between the two methods. There was no linear relationship observed between the bacteriological index (BI) and the morphological index (MI) with the counts per minute (cpm) output. CONCLUSION The results indicate the ability of this RR assay to detect viability; however a comparison with another sensitive method would further validate the assay system.
Network Structure and Observational Learning: Evidence from a Location-Based Social Network

In recent years, there has been stellar growth of location-based/enabled social networks in which people can "check in" to physical venues they are visiting and share with friends. In this paper, we hypothesize that the "check-ins" made by friends help users learn the potential payoff of visiting a venue. We argue that this learning-in-a-network process differs from the classic observational learning model in a subtle yet important way: Rather than from anonymous others, the agents learn from their network friends, about whose tastes in experience goods the agents are better informed. The empirical analyses are conducted on a unique data set in which we observe both the explicit interpersonal relationships and their ensuing check-ins. The key result is that the proportion of checked-in friends is not positively associated with the likelihood of a new visit, rejecting the prediction of the conventional observational learning model. Drawing on the literature in sociology and computer science, we show that weighting the friends' check-ins by a parsimonious proximity measure can yield a more intuitive result than the plain proportion does. Repeated check-ins by friends are found to have a pronounced effect. Our empirical result calls for the revisiting of observational learning in a social network setting. It also suggests that practitioners should incorporate network proximity when designing social recommendation products and conducting promotional campaigns in a social network.
Incorporation of Three Endocytosed Varicella-Zoster Virus Glycoproteins, gE, gH, and gB, into the Virion Envelope

ABSTRACT The cytoplasmic tails of all three major varicella-zoster virus (VZV) glycoproteins, gE, gH, and gB, harbor functional tyrosine-based endocytosis motifs that mediate internalization. The aim of the present study was to examine whether endocytosis from the plasma membrane is a cellular route by which VZV glycoproteins are delivered to the final envelopment compartment. In this study, we demonstrated that internalization of the glycoproteins occurred in the first 24 h postinfection but was reduced later in infection. Using surface biotinylation of VZV-infected cells followed by a glutathione cleavage assay, we showed that endocytosis was independent of antibody binding to gE, gH, and gB. Subsequently, with this assay, we demonstrated that biotinylated gE, gH, and gB retrieved from the cell surface were incorporated into nascent virus particles isolated after density gradient sedimentation. To confirm and extend this finding, we repeated the above sedimentation step and specifically detected envelopes decorated with Streptavidin-conjugated gold beads on a majority of complete virions through examination by transmission electron microscopy. In addition, a gE-gI complex and a gE-gH complex were found on the virions. Therefore, the above studies established that VZV subsumed a postendocytosis trafficking pathway as one mechanism by which to deliver viral glycoproteins to the site of virion assembly in the cytoplasm. Furthermore, since a recombinant VZV genome lacking only endocytosis-competent gE cannot replicate, these results supported the conclusion that the endocytosis-envelopment pathway is an essential component of the VZV life cycle.
FDG PET/CT Can Assess the Response of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiotherapy: Evidence From Meta-analysis and Systematic Review

Introduction Neoadjuvant chemoradiotherapy (CRT) is indicated in locally advanced rectal adenocarcinoma where there is a high risk of local recurrence based on preoperative imaging. Optimal radiological assessment of CRT response is unknown, and metabolic assessment of the tumor has been suggested to gauge response before surgical resection. Patients and Methods A systematic search of the MEDLINE database was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement to identify papers comparing pre- and post-CRT PET/CT in patients with locally advanced rectal adenocarcinoma with histopathological assessment of tumor regression. Papers were assessed with the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Meta-analysis was performed for response index (RI) and SUVmax post-CRT. Results Ten of 69 studies met inclusion criteria containing a total of 538 patients. Methodological quality was high with low heterogeneity. In all studies, post-CRT PET/CT showed a reduction in SUVmax and the RI irrespective of histological findings. Tumors confirmed to have regressed after CRT had a mean difference of 12.21% higher RI (95% confidence interval, 6.51–17.91; P < 0.00001) compared with nonresponders. Mean difference between pre- and post-CRT SUVmax groups was −2.48 (95% confidence interval, −3.06 to −1.89; P < 0.00001) with histopathological responders having a lower post-CRT SUVmax. Conclusions The available evidence suggests that PET/CT may be a useful addition to the current imaging modalities in the assessment of treatment response.
Peripheral synapses and giant neurons in whip spiders

Among invertebrates the synapses between neurons are generally restricted to ganglia, i.e., to the central nervous system (CNS). As an exception, synapses occur in the sensory nerves of arachnid legs, indicating that some nervous integration is already taking place far out in the periphery. In the antenniform legs of whip spiders (Amblypygi), a very special synaptic circuit is present. These highly modified legs contain several large interneurons (giant neurons) that receive mechanosensory input from 700–1,500 tarsal bristles. Some of the sensory cell axons contact a giant neuron at its short, branched dendrite, a few at the soma, but most synapse onto the long giant axon. The fine structure of these synapses resembles that of typical chemical synapses in other arthropods. Although thousands of sensory fibers converge on a single giant neuron, there is no reduction in the actual number of sensory fibers, because these afferent fibers continue their course to the CNS after having made several en passant synapses onto the giant neuron. Touching a single tarsal bristle is sufficient to elicit action potentials in a giant neuron. Owing to the large diameter of the giant axon (10–20 μm), the action potentials reach the CNS within 55 ms, at conduction velocities of up to 7 m/s. However, mechanical stimulation of the tarsal bristles does not elicit a fast escape response, in contrast to giant fiber systems in earthworms, certain insects, and crayfishes. A quick escape is observed in whip spiders, but only after stimulation of the filiform hairs (trichobothria) on the regular walking legs. Although the giant fiber system in the antenniform legs undoubtedly provides a fast sensory pathway, its biological significance is not clearly understood at the moment. Microsc. Res. Tech. 58:272–282, 2002. © 2002 Wiley‐Liss, Inc.
DNA helicase activity of SV40 large tumor antigen.

Large tumor antigen (T antigen) was extracted from SV40‐infected African Green Monkey cells and purified to homogeneity by immunoaffinity chromatography. The purified T antigen preparations unwind DNA duplices of greater than 120 bp in a reaction which is dependent on magnesium ions and ATP hydrolysis. Based on these and other properties of the reaction we classify this newly discovered enzymatic activity as a eukaryotic DNA helicase. The helicase and the known ATPase function of T antigen cosediment with the mono‐ or dimeric 4‐6 S form of T antigen, but not with higher T antigen aggregates. The helicase activity seems to be an intrinsic function of SV40 T antigen. First, several different T antigen‐specific monoclonal antibodies interfere with the DNA unwinding activity; monoclonals which are known to reduce the T antigen‐specific ATPase most strongly inhibited the helicase reaction. Second, mutant T antigens with impaired ATPase function also showed a reduced DNA unwinding activity.