Conservation of orbital angular momentum throughout amplification of high order harmonics in Ni-like krypton and silver plasmas.

In this article we present modelling results of the amplification of High Order Harmonics (HOH) carrying orbital angular momentum (OAM) in plasma amplifiers created from krypton gas and silver solid targets. The resulting amplified beam is characterized in terms of intensity, phase and decomposition in helical and Laguerre-Gauss modes. Results show that the amplification process conserves OAM, although some degradation is apparent. Several structures appear in the intensity and phase profiles. These structures have been characterized with our model and related to refraction and interference with the plasma self-emission. Thus, these results not only demonstrate the capability of plasma amplifiers to deliver HOH amplified beams carrying OAM but also pave the way towards using HOH carrying OAM as a probe beam to diagnose the dynamics of hot, dense plasmas.

Note on a stepwise procedure for rejecting at least k out of m hypotheses: A simple Holm-type formulation and proof.

Mielke et al. (2021) proposed a stepwise multiple testing procedure (MTP) based on marginal p-values for rejecting at least k out of m null hypotheses. Briefly, the MTP cannot reject less than k hypotheses, but this property improves the power to reject k or more hypotheses relative to the stepdown MTP of Holm (1979). Mielke et al. discussed why such an MTP is of interest in the context of biosimilarity developments. This article describes how a slight modification of Holm's simple direct arguments can be used as an alternative to the closed-testing arguments of Mielke et al. to show the strong control of the family-wise error rate. This modification is based on a Holm-type formulation of the rejection algorithm where each step involves a single ordered p-value. With k equal to one, the stepwise MTP reduces to Holm's stepdown MTP. The MTP is valid quite generally. A version of the MTP with weights for hypotheses is also described and discussed. As in the case without weights: (a) a modification of Holm's arguments can be used; (b) with k equal to one, the MTP reduces to Holm's MTP with weights; and (c) the MTP is valid quite generally.

Decreased Immune Response in Alexithymic Women: A One-Year Longitudinal Study.

Although previous cross-sectional studies suggested significantly dysregulated immune response in alexithymia, there is a lack of longitudinal studies. We sought to determine the reliability of the reported relationship between alexithymia and decreased immune response in a longitudinal study. Thirty-eight healthy women who had participated in a cross-sectional study were recontacted 1-year later. Of this sample, 26 were finally included: 13 females who had been found to be alexithymic, and 13 females who were classified as non-alexithymic under the 20-item Toronto Alexithymia Scale during the first phase of the study. A year later, they were still healthy women without any psychiatric disorders, their ages now ranging from 19 to 28 years old. Lymphocyte subset counts (CD4, CD8), in vitro production of interleukin 1ß (IL-1ß), IL-2, IL-4, and IL-10 by phytohemagglutinin stimulated peripheral blood lymphocytes, as well as serum cortisol levels, were compared between women with and without alexithymia. One-year later, alexithymic women still had significantly lowered in vitro production of IL-2 and IL-4, with lowered IL-2/IL-10 ratio and a reduced percentage of CD4. This is the first ever published study assessing cytokine production during a follow-up of alexithymics. Although our results should be interpreted with caution due the small sample size, they suggest a sustained reduction in both major type 1 and type 2 cytokines while the former seems to be more affected. The potential long-term health impact, if any, is still to be determined.

Shack-Hartmann Wavefront Sensing of Ultrashort Optical Vortices.

Light beams carrying Orbital Angular Momentum (OAM), also known as optical vortices (OV), have led to fascinating new developments in fields ranging from quantum communication to novel light-matter interaction aspects. Even though several techniques have emerged to synthesize these structured-beams, their detection, in particular, single-shot amplitude, wavefront, and modal content characterization, remains a challenging task. Here, we report the single-shot amplitude, wavefront, and modal content characterization of ultrashort OV using a Shack-Hartmann wavefront sensor. These vortex beams are obtained using spiral phase plates (SPPs) that are frequently used for high-intensity applications. The reconstructed wavefronts display a helical structure compatible with the topological charge induced by the SPPs. We affirm the accuracy of the optical field reconstruction by the wavefront sensor through an excellent agreement between the numerically backpropagated and experimentally obtained intensity distribution at the waist. Consequently, through Laguerre-Gauss (LG) decomposition of the reconstructed fields, we reveal the radial and azimuthal mode composition of vortex beams under different conditions. The potential of our method is further illustrated by characterizing asymmetric Gaussian vortices carrying fractional average OAM, and a realtime topological charge measurement at a 10Hz repetition rate. These results can promote Shack-Hartmann wavefront sensing as a single-shot OV characterization tool.

Towards subpicosecond pulses from solid target plasma based seeded soft X-ray laser.

We investigate the coherence of plasma-based soft X-ray laser (XRL) for different conditions that can alter the electron density in the gain region. We first measure the source temporal coherence in amplified spontaneous emission (ASE) mode. We develop a data analysis procedure to extract both its spectral width and pulse duration. These findings are in agreement with the spectral line shape simulations and seeded operation experimental results. Utilizing the deduced spectral width and pulse duration in a one-dimensional Bloch-Maxwell code, we reproduce the experimental temporal coherence properties of the seeded-XRL. Finally, we demonstrate efficient lasing in ASE and seeded mode at an electron density two times higher than the routine conditions. In this regime, using Bloch-Maxwell modeling, we predict the pulse duration of the seeded XRL to be ∼500fs.

Evidence of partial temporal coherence effects in the linear autocorrelation of extreme ultraviolet laser pulses.

We study how the degree of temporal coherence of plasma-based extreme ultraviolet lasers operated in the amplification of the spontaneous emission mode is encoded in the shape of the linear autocorrelation function, which is obtained from the variation of the fringe visibility while varying the delay in a variable path-difference interferometer. We discuss the implications of this effect when the technique is used to infer the spectral properties of the source. Our numerical simulations, based on a partial coherence model developed by other authors for x-ray free electron lasers, are in good agreement with previously reported sets of measurements, illustrating similar statistical properties for both sources.

One long and two short pumping pulses control for plasma x-ray amplifier optimization.

Development of efficient soft x-ray laser plasma amplifiers adapted to seeded operation, requires a better control over amplifier transverse spatial extent, brilliance control and gain lifetime. Here it is shown that pumping the plasma amplifier with one long and two short pump pulses (1L2S) provides advantages in terms of control for the specified parameters in the case of Ni-like Ag x-ray laser. Also, significant tunability of the gain lifetime in the 1L2S pumping scheme for Ne-like Ti x-ray laser is observed. Direct harmonics seeding and chirped harmonics seeding amplification approaches may benefit from the control of the gain lifetime, in terms of better use of the pump energy and as a way to reduce the amplified spontaneous emission in x-ray lasers.

Q-switched laser-assisted grazing incidence pumping (QAGRIP) for efficient soft x-ray laser generation.

We have investigated a new scheme for laser plasma transient collisional soft x-ray lasers based on the use of an additional laser to produce the preplasma. Soft x-ray emission measurements made for different solid targets are presented and discussed. A significant enhancement of the SXRL emission as compared to double-pulse single-beam grazing incidence (DGRIP) using the same pump laser is reported for 13.9- and 32.6-nm SXRL wavelengths.

Enhanced high harmonic generation driven by high-intensity laser in argon gas-filled hollow core waveguide.

We show that a significant enhancement of the photon flux produced by high harmonic generation can be obtained through guided configuration at high laser intensity largely above the saturation intensity. We identify two regimes. At low pressure, we observe an intense second plateau in the high harmonic spectrum in argon. At relatively high pressure, complex interplay between strongly time-dependent ionization processes and propagation effects leads to important spectral broadening without loss of spectral brightness. We show that the relevant parameter for this physical process is the product of laser peak power by gas pressure. We compare source performances with high harmonic generation using a gas jet in loose focusing geometry and conclude that the source developed is a good candidate for injection devices such as seeded soft x-ray lasers or free electron lasers in the soft x-ray range.

Thin film beam splitter multiple short pulse generation for enhanced Ni-like Ag x-ray laser emission.

An alternative, novel multiple pulse generation scheme was implemented directly after the optical compressor output of an x-ray pump laser. The new method uses a polarization sensitive thin film beam splitter and a half-wavelength wave plate for tuning the energy ratio in the multiple short pulses. Based on this method, an extensive study was made of the running parameters for a grazing incidence pumped silver x-ray laser (XRL) pumped with a long pulse of 145 mJ in 6 ns at 532 nm and up to 1.45 J in few picoseconds at 810 nm. Fivefold enhancement in the emission of the silver XRL was demonstrated using the new pump method.

Simultaneous confidence regions for closed tests, including Holm-, Hochberg-, and Hommel-related procedures.

The derivation of simultaneous confidence regions for some multiple-testing procedures (MTPs) of practical interest has remained an unsolved problem. This is the case, for example, for Hochberg's step-up MTP and Hommel's more powerful MTP that is neither a step-up nor a step-down procedure. It is shown in this article how the direct approach used previously by the author to construct confidence regions for certain closed-testing procedures (CTPs) can be extended to a rather general setup. The general results are then applied to a situation with one-sided inferences and CTPs belonging to a class studied by Wei Liu. This class consists of CTPs based on ordered marginal p-values. It includes Holm's, Hochberg's, and Hommel's MTPs. A property of the confidence regions derived for these three MTPs is that no confidence assertions sharper than rejection assertions can be made unless all null hypotheses are rejected. Briefly, this is related to the fact that these MTPs are quite powerful. The class of CTPs considered includes, however, also MTPs related to Holm's, Hochberg's, and Hommel's MTPs that are less powerful but are such that confidence assertions sharper than rejection assertions are possible even if not all null hypotheses are rejected. One may thus choose and prespecify such an MTP, though this is at the cost of less rejection power.

Note on simultaneous inferences about non-inferiority and superiority for a primary and a secondary endpoint.

In their review of challenges to multiple testing in clinical trials, Hung and Wang (2010) considered the situation where a treatment is to be compared with an active comparator and the aim is to show non-inferiority and (if possible) superiority with respect to a primary and a secondary endpoint. This note extends their discussion of this particular situation, taking the sequentially rejective procedure they used for illustration as a starting point. Some alternative multiple testing procedures (MTPs) are considered, and corresponding simultaneous confidence regions are discussed that provide additional information "for free". The choice may then be based on the properties of these MTPs and corresponding confidence regions.

Confidence regions for Bonferroni-based closed tests extended to more general closed tests.

Simultaneous confidence regions were recently derived for a large class of Bonferroni-based closed testing procedures (CTPs). This class and a very useful subclass of graphical procedures are described, and it is then shown how the direct approach of Guilbaud (2008) for such CTPs can be extended to cover also CTPs that are not Bonferroni based and that may utilize dependencies not utilized by Bonferroni-based procedures. The simultaneous confidence regions that can be derived through this extension include the known confidence bounds for the step-down version of one-sided Dunnett-type multiple comparisons versus a control in the balanced case. As a simple illustration of how the general results can be applied, similar bounds are derived for the unbalanced case. As a further, more elaborated, illustration, confidence bounds are derived for the Dunnett gatekeeping procedure of Xu et al. (2009) based on a primary and a secondary variable. In this procedure, primary rejections are made through an ordinary one-sided Dunnett procedure, and secondary rejections are restricted to treatment comparisons with primary rejections. It turns out that ordinary Dunnett-type confidence assertions can be made for all primary comparisons without rejections. Interestingly, informative confidence assertions can be made also for secondary comparisons without rejections, but only in case of matching primary rejections. The gatekeeping is thus naturally extended to confidence assertions.

Are treatment options related to alexithymia in eating disorders? Results from a three-year naturalistic longitudinal study.

OBJECTIVE: Longitudinal studies have shown that alexithymic features can interfere with treatment response in eating disorders. However, an alternative hypothesis could be that clinicians faced with alexithymic patients chose different treatment options according to their perceptions of these patients. The aim of this investigation was to explore the relationships between alexithymic features and treatment options provided by professionals in a naturalistic prospective study of eating disorders. METHODS: We conducted a 3-year longitudinal study exploring a sample of 102 DSM-IV Eating Disorder patients with the Toronto Alexithymia Scale (TAS-20). All treatments received during follow-up were recorded and recoded dichotomously, and crossed with the variation of alexithymic categories (cut-off≥56) between inclusion and follow-up. RESULTS: Patients received different treatments according to their alexithymic profile, in terms both of number and type of treatment received. Patients with high, stable levels of alexithymia received overall more treatments, and significantly more antidepressants, than non-alexithymic patients. Patients who became alexithymics during follow-up were more often rehospitalized and received fewer regular psychotherapies than the non-alexithymic patients. CONCLUSIONS: Professionals should carefully monitor these personality features and be aware of the potential impact of alexithymic features on treatment compliance and on treatment choice for eating disordered patients.

Optimization of a tabletop high-repetition-rate soft x-ray laser pumped in double-pulse single-beam grazing incidence.

This Letter reports on the optimization of a tabletop nickel-like molybdenum transient collisionally excited soft x-ray laser (SXRL) at 18.9 nm performed by a double-pulse single-beam grazing incidence pumping (DGRIP). This scheme allows for the first time, to our knowledge, the full control of the pump laser parameters including the pre-pulse duration optimally generating the SXRL amplifier under a grazing incidence. The single-beam geometry of the collinear double-pulse propagation guarantees the ideal overlap of the pre-pulse and main pulse from shot to shot resulting in a more efficient and highly stable SXRL output. SXRL energies up to 2.2 microJ are obtained with a total pump energy less than 1 J for several hours at a 10 Hz repetition rate without realignment under once optimized double pumping pulse parameters including energy ratio, time delay, pre-pulse and main pulse durations, and line focus width.

Alternative confidence regions for bonferroni-based closed-testing procedures that are not alpha-exhaustive.

This article complements the results in Guilbaud (Biometrical Journal 2008; 50:678-692). Simultaneous confidence regions were derived in that article that correspond to any given multiple testing procedure (MTP) in a fairly large class of consonant closed-testing procedures based on marginal p-values and weighted Bonferroni tests for intersection hypotheses. This class includes Holm's MTP, the fixed-sequence MTP, gatekeeping MTPs, fallback MTPs, multi-stage fallback MTPs, and recently proposed MTPs specified through a graphical representation and associated rejection algorithm. More general confidence regions are proposed in this article. These regions are such that for certain underlying MTPs which are not alpha-exhaustive, they lead to confidence assertions that may be sharper than rejection assertions for some rejected null hypotheses H when not all Hs are rejected, which is not the case with the previously proposed regions. In fact, various alternative confidence regions may be available for such an underlying MTP. These results are shown through an extension of the previous direct arguments (without invoking the partitioning principle), and under the same general setup; so for instance, estimated quantities and marginal confidence regions are not restricted to be of any particular kinds/dimensions. The relation with corresponding confidence regions of Strassburger and Bretz (Statistics in Medicine 2008; 27:4914-4927) is described. The results are illustrated with fallback and parallel-gatekeeping MTPs.

Decreased immune response in alexithymic women: a cross-sectional study.

It has been reported in a few studies that alexithymia is associated with impaired immune response but results are still contradictory. The present study investigates whether alexithymia is associated with lower cell-mediated (Th-1) immune response. Fifty-one healthy 18-27-year-old women were selected from healthy subjects on the basis of high or low cut-off scores on the 20-item Toronto Alexithymia Scale (TAS-20). They were evaluated using standardized psychiatric rating scales notably the Hospital Anxiety Depressive Scale (HAD) and the Mini Neuropsychiatric Interview (MINI). None of the subjects were suffering from psychiatric disorders. Twenty-seven were classified as alexithymics and 24 as non-alexithymics according to the TAS-20. Blood was drawn for lymphocyte subset counts (CD4, CD8), in vitro production of interleukin 1 (IL-1beta), IL-2, IL-4, and IL-10 by phytohaemagglutinin stimulated peripheral lymphocytes, and cortisol. Women with alexithymia exhibited decreased interleukin 1beta, IL-2 and IL-4 production with reduced ratios of Th1/Th2 (IL-2/IL-10) and of CD4/CD8, as well as reduced CD4 percentages. IL-2 and IL-4 production remained significantly diminished in the alexithymic group, even after adjusting for between-group differences in anxiety and depression levels on the HAD. This study further demonstrates that alexithymic women have altered immune function, with a predominance of depressed cell-mediated immunity and a skewed Th1/Th2 ratio towards Th2 response.

Simultaneous confidence regions corresponding to Holm's step-down procedure and other closed-testing procedures.

Holm's (1979) step-down multiple-testing procedure (MTP) is appealing for its flexibility, transparency, and general validity, but the derivation of corresponding simultaneous confidence regions has remained an unsolved problem. This article provides such confidence regions. In fact, simultanenous confidence regions are provided for any MTP in the class of short-cut consonant closed-testing procedures based on marginal p -values and weighted Bonferroni tests for intersection hypotheses considered by Hommel, Bretz and Maurer (2007). In addition to Holm's MTP, this class includes the fixed-sequence MTP, recently proposed gatekeeping MTPs, and the fallback MTP. The simultaneous confidence regions are generally valid if underlying marginal p -values and corresponding marginal confidence regions (assumed to be available) are valid. The marginal confidence regions and estimated quantities are not assumed to be of any particular kinds/dimensions. Compared to the rejections made by the MTP for the family of null hypotheses H under consideration, the proposed confidence regions provide extra free information. In particular, with Holm's MTP, such extra information is provided: for all nonrejected H s, in case not all H s are rejected; or for certain (possibly all) H s, in case all H s are rejected. In case not all H s are rejected, no extra information is provided for rejected H s. This drawback seems however difficult to overcome. Illustrations concerning clinical studies are given.